1
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Walker RV, Yao Q, Xu H, Maranto A, Swaney KF, Ramachandran S, Li R, Cassina L, Polster BM, Outeda P, Boletta A, Watnick T, Qian F. Fibrocystin/Polyductin releases a C-terminal fragment that translocates into mitochondria and suppresses cystogenesis. Nat Commun 2023; 14:6513. [PMID: 37845212 PMCID: PMC10579373 DOI: 10.1038/s41467-023-42196-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/03/2023] [Indexed: 10/18/2023] Open
Abstract
Fibrocystin/Polyductin (FPC), encoded by PKHD1, is associated with autosomal recessive polycystic kidney disease (ARPKD), yet its precise role in cystogenesis remains unclear. Here we show that FPC undergoes complex proteolytic processing in developing kidneys, generating three soluble C-terminal fragments (ICDs). Notably, ICD15, contains a novel mitochondrial targeting sequence at its N-terminus, facilitating its translocation into mitochondria. This enhances mitochondrial respiration in renal epithelial cells, partially restoring impaired mitochondrial function caused by FPC loss. FPC inactivation leads to abnormal ultrastructural morphology of mitochondria in kidney tubules without cyst formation. Moreover, FPC inactivation significantly exacerbates renal cystogenesis and triggers severe pancreatic cystogenesis in a Pkd1 mouse mutant Pkd1V/V in which cleavage of Pkd1-encoded Polycystin-1 at the GPCR Proteolysis Site is blocked. Deleting ICD15 enhances renal cystogenesis without inducing pancreatic cysts in Pkd1V/V mice. These findings reveal a direct link between FPC and a mitochondrial pathway through ICD15 cleavage, crucial for cystogenesis mechanisms.
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Affiliation(s)
- Rebecca V Walker
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Qin Yao
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Hangxue Xu
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Anthony Maranto
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristen F Swaney
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sreekumar Ramachandran
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Mechanobiology Institute and Department of Biological Sciences, National University of Singapore, Singapore, 117411, Singapore
| | - Laura Cassina
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Patricia Outeda
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alessandra Boletta
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Terry Watnick
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
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2
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Wang Z, Zhang S, Du J, Lachance BB, Chen S, Polster BM, Jia X. Neuroprotection of NSC Therapy is Superior to Glibenclamide in Cardiac Arrest-Induced Brain Injury via Neuroinflammation Regulation. Transl Stroke Res 2023; 14:723-739. [PMID: 35921049 PMCID: PMC9895128 DOI: 10.1007/s12975-022-01047-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/05/2022] [Indexed: 02/05/2023]
Abstract
Cardiac arrest (CA) is common and devastating, and neuroprotective therapies for brain injury after CA remain limited. Neuroinflammation has been a target for two promising but underdeveloped post-CA therapies: neural stem cell (NSC) engrafting and glibenclamide (GBC). It is critical to understand whether one therapy has superior efficacy over the other and to further understand their immunomodulatory mechanisms. In this study, we aimed to evaluate and compare the therapeutic effects of NSC and GBC therapies post-CA. In in vitro studies, BV2 cells underwent oxygen-glucose deprivation (OGD) for three hours and were then treated with GBC or co-cultured with human NSCs (hNSCs). Microglial polarization phenotype and TLR4/NLRP3 inflammatory pathway proteins were detected by immunofluorescence staining. Twenty-four Wistar rats were randomly assigned to three groups (control, GBC, and hNSCs, N = 8/group). After 8 min of asphyxial CA, GBC was injected intraperitoneally or hNSCs were administered intranasally in the treatment groups. Neurological-deficit scores (NDSs) were assessed at 24, 48, and 72 h after return of spontaneous circulation (ROSC). Immunofluorescence was used to track hNSCs and quantitatively evaluate microglial activation subtype and polarization. The expression of TLR4/NLRP3 pathway-related proteins was quantified via Western blot. The in vitro studies showed the highest proportion of activated BV2 cells with an increased expression of TLR4/NLRP3 signaling proteins were found in the OGD group compared to OGD + GBC and OGD + hNSCs groups. NDS showed significant improvement after CA in hNSC and GBC groups compared to controls, and hNSC treatment was superior to GBC treatment. The hNSC group had more inactive morphology and anti-inflammatory phenotype of microglia. The quantified expression of TLR4/NLRP3 pathway-related proteins was significantly suppressed by both treatments, and the suppression was more significant in the hNSC group compared to the GBC group. hNSC and GBC therapy regulate microglial activation and the neuroinflammatory response in the brain after CA through TLR4/NLRP3 signaling and exert multiple neuroprotective effects, including improved neurological function and shortened time of severe neurological deficit. In addition, hNSCs displayed superior inflammatory regulation over GBC.
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Affiliation(s)
- Zhuoran Wang
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Shuai Zhang
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jian Du
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Brittany Bolduc Lachance
- Program in Trauma, Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Songyu Chen
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Brian M Polster
- Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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3
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Strogulski NR, Portela LV, Polster BM, Loane DJ. Fundamental Neurochemistry Review: Microglial immunometabolism in traumatic brain injury. J Neurochem 2023; 167:129-153. [PMID: 37759406 PMCID: PMC10655864 DOI: 10.1111/jnc.15959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023]
Abstract
Traumatic brain injury (TBI) is a devastating neurological disorder caused by a physical impact to the brain that promotes diffuse damage and chronic neurodegeneration. Key mechanisms believed to support secondary brain injury include mitochondrial dysfunction and chronic neuroinflammation. Microglia and brain-infiltrating macrophages are responsible for neuroinflammatory cytokine and reactive oxygen species (ROS) production after TBI. Their production is associated with loss of homeostatic microglial functions such as immunosurveillance, phagocytosis, and immune resolution. Beyond providing energy support, mitochondrial metabolic pathways reprogram the pro- and anti-inflammatory machinery in immune cells, providing a critical immunometabolic axis capable of regulating immunologic response to noxious stimuli. In the brain, the capacity to adapt to different environmental stimuli derives, in part, from microglia's ability to recognize and respond to changes in extracellular and intracellular metabolite levels. This capacity is met by an equally plastic metabolism, capable of altering immune function. Microglial pro-inflammatory activation is associated with decreased mitochondrial respiration, whereas anti-inflammatory microglial polarization is supported by increased oxidative metabolism. These metabolic adaptations contribute to neuroimmune responses, placing mitochondria as a central regulator of post-traumatic neuroinflammation. Although it is established that profound neurometabolic changes occur following TBI, key questions related to metabolic shifts in microglia remain unresolved. These include (a) the nature of microglial mitochondrial dysfunction after TBI, (b) the hierarchical positions of different metabolic pathways such as glycolysis, pentose phosphate pathway, glutaminolysis, and lipid oxidation during secondary injury and recovery, and (c) how immunometabolism alters microglial phenotypes, culminating in chronic non-resolving neuroinflammation. In this basic neurochemistry review article, we describe the contributions of immunometabolism to TBI, detail primary evidence of mitochondrial dysfunction and metabolic impairments in microglia and macrophages, discuss how major metabolic pathways contribute to post-traumatic neuroinflammation, and set out future directions toward advancing immunometabolic phenotyping in TBI.
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Affiliation(s)
- Nathan R. Strogulski
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Luis V. Portela
- Neurotrauma and Biomarkers Laboratory, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Brian M. Polster
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - David J. Loane
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
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4
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Yan W, Zhong Y, Hu X, Xu T, Zhang Y, Kales S, Qu Y, Talley DC, Baljinnyam B, LeClair CA, Simeonov A, Polster BM, Huang R, Ye Y, Rai G, Henderson MJ, Tao D, Fang S. Auranofin targets UBA1 and enhances UBA1 activity by facilitating ubiquitin trans-thioesterification to E2 ubiquitin-conjugating enzymes. Nat Commun 2023; 14:4798. [PMID: 37558718 PMCID: PMC10412574 DOI: 10.1038/s41467-023-40537-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 07/25/2023] [Indexed: 08/11/2023] Open
Abstract
UBA1 is the primary E1 ubiquitin-activating enzyme responsible for generation of activated ubiquitin required for ubiquitination, a process that regulates stability and function of numerous proteins. Decreased or insufficient ubiquitination can cause or drive aging and many diseases. Therefore, a small-molecule enhancing UBA1 activity could have broad therapeutic potential. Here we report that auranofin, a drug approved for the treatment of rheumatoid arthritis, is a potent UBA1 activity enhancer. Auranofin binds to the UBA1's ubiquitin fold domain and conjugates to Cys1039 residue. The binding enhances UBA1 interactions with at least 20 different E2 ubiquitin-conjugating enzymes, facilitating ubiquitin charging to E2 and increasing the activities of seven representative E3s in vitro. Auranofin promotes ubiquitination and degradation of misfolded ER proteins during ER-associated degradation in cells at low nanomolar concentrations. It also facilitates outer mitochondrial membrane-associated degradation. These findings suggest that auranofin can serve as a much-needed tool for UBA1 research and therapeutic exploration.
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Affiliation(s)
- Wenjing Yan
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Yongwang Zhong
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Xin Hu
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Tuan Xu
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Yinghua Zhang
- Center for Innovative Biomedical Resources, Biosensor Core, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Stephen Kales
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Yanyan Qu
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Daniel C Talley
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Bolormaa Baljinnyam
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Christopher A LeClair
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ruili Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ganesha Rai
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Mark J Henderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Dingyin Tao
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA.
| | - Shengyun Fang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Program in Oncology, UM Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
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5
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Samaddar S, O’Neal AJ, Marnin L, Rolandelli A, Singh N, Wang X, Butler LR, Rangghran P, Laukaitis HJ, Cabrera Paz FE, Fiskum GM, Polster BM, Pedra JHF. Metabolic disruption impacts tick fitness and microbial relationships. bioRxiv 2023:2023.05.26.542501. [PMID: 37292783 PMCID: PMC10245996 DOI: 10.1101/2023.05.26.542501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Arthropod-borne microbes rely on the metabolic state of a host to cycle between evolutionarily distant species. For instance, arthropod tolerance to infection may be due to redistribution of metabolic resources, often leading to microbial transmission to mammals. Conversely, metabolic alterations aids in pathogen elimination in humans, who do not ordinarily harbor arthropod-borne microbes. To ascertain the effect of metabolism on interspecies relationships, we engineered a system to evaluate glycolysis and oxidative phosphorylation in the tick Ixodes scapularis. Using a metabolic flux assay, we determined that the rickettsial bacterium Anaplasma phagocytophilum and the Lyme disease spirochete Borrelia burgdorferi, which are transstadially transmitted in nature, induced glycolysis in ticks. On the other hand, the endosymbiont Rickettsia buchneri, which is transovarially maintained, had a minimal effect on I. scapularis bioenergetics. Importantly, the metabolite β-aminoisobutyric acid (BAIBA) was elevated during A. phagocytophilum infection of tick cells following an unbiased metabolomics approach. Thus, we manipulated the expression of genes associated with the catabolism and anabolism of BAIBA in I. scapularis and detected impaired feeding on mammals, reduced bacterial acquisition, and decreased tick survival. Collectively, we reveal the importance of metabolism for tick-microbe relationships and unveil a valuable metabolite for I. scapularis fitness.
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Affiliation(s)
- Sourabh Samaddar
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Anya J. O’Neal
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Liron Marnin
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Agustin Rolandelli
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Nisha Singh
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Xiaowei Wang
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - L. Rainer Butler
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Parisa Rangghran
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Hanna J. Laukaitis
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Francy E. Cabrera Paz
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
| | - Gary M. Fiskum
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Brian M. Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Joao H. F. Pedra
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA
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6
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Passaniti A, Kim MS, Polster BM, Shapiro P. Targeting mitochondrial metabolism for metastatic cancer therapy. Mol Carcinog 2022; 61:827-838. [PMID: 35723497 PMCID: PMC9378505 DOI: 10.1002/mc.23436] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 05/18/2022] [Accepted: 05/27/2022] [Indexed: 02/06/2023]
Abstract
Primary tumors evolve metabolic mechanisms favoring glycolysis for adenosine triphosphate (ATP) generation and antioxidant defenses. In contrast, metastatic cells frequently depend on mitochondrial respiration and oxidative phosphorylation (OxPhos). This reliance of metastatic cells on OxPhos can be exploited using drugs that target mitochondrial metabolism. Therefore, therapeutic agents that act via diverse mechanisms, including the activation of signaling pathways that promote the production of reactive oxygen species (ROS) and/or a reduction in antioxidant defenses may elevate oxidative stress and inhibit tumor cell survival. In this review, we will provide (1) a mechanistic analysis of function-selective extracellular signal-regulated kinase-1/2 (ERK1/2) inhibitors that inhibit cancer cells through enhanced ROS, (2) a review of the role of mitochondrial ATP synthase in redox regulation and drug resistance, (3) a rationale for inhibiting ERK signaling and mitochondrial OxPhos toward the therapeutic goal of reducing tumor metastasis and treatment resistance. Recent reports from our laboratories using metastatic melanoma and breast cancer models have shown the preclinical efficacy of novel and rationally designed therapeutic agents that target ERK1/2 signaling and mitochondrial ATP synthase, which modulate ROS events that may prevent or treat metastatic cancer. These findings and those of others suggest that targeting a tumor's metabolic requirements and vulnerabilities may inhibit metastatic pathways and tumor growth. Approaches that exploit the ability of therapeutic agents to alter oxidative balance in tumor cells may be selective for cancer cells and may ultimately have an impact on clinical efficacy and safety. Elucidating the translational potential of metabolic targeting could lead to the discovery of new approaches for treatment of metastatic cancer.
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Affiliation(s)
- Antonino Passaniti
- Research Health Scientist, The Veteran's Health Administration Research & Development Service (VAMHCS), VA Maryland Health Care System (VAMHCS), Baltimore VA Medical Center, Baltimore, Maryland, USA
- Department of Pathology and Department of Biochemistry & Molecular Biology, the Program in Molecular Medicine and the Marlene & Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland USA
| | - Myoung Sook Kim
- Department of Pathology and Department of Biochemistry & Molecular Biology, the Program in Molecular Medicine and the Marlene & Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland USA
| | - Brian M. Polster
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Paul Shapiro
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore Maryland, USA
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7
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Polster BM, Mark KA, Arze R, Hudson D. Calpain-Independent Intracellular Protease Activity Is Elevated in Excitotoxic Cortical Neurons Prior to Delayed Calcium Deregulation and Mitochondrial Dysfunction. Biomolecules 2022; 12:biom12071004. [PMID: 35883560 PMCID: PMC9313431 DOI: 10.3390/biom12071004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/11/2022] [Accepted: 07/18/2022] [Indexed: 02/01/2023] Open
Abstract
Glutamate excitotoxicity contributes to many neurodegenerative diseases. Excessive glutamate receptor-mediated calcium entry causes delayed calcium deregulation (DCD) that coincides with abrupt mitochondrial depolarization. We developed cA-TAT, a live-cell protease activity reporter based on a vimentin calpain cleavage site, to test whether glutamate increases protease activity in neuronal cell bodies prior to DCD. Treatment of rat cortical neurons with excitotoxic (100 µM) glutamate increased the low baseline rate of intracellular cA-TAT proteolysis by approximately three-fold prior to DCD and by approximately seven-fold upon calcium deregulation. The glutamate-induced rate enhancement prior to DCD was suppressed by glutamate receptor antagonists, but not by calpain or proteasome inhibitors, whereas DCD-stimulated proteolysis was partly attenuated by the proteasome inhibitor MG132. Further suggesting that cA-TAT cleavage is calpain-independent, cA-TAT fluorescence was observed in immortalized Capn4 knockout fibroblasts lacking the regulatory calpain subunit. About half of the neurons lost calcium homeostasis within two hours of a transient, 20 min glutamate receptor stimulation. These neurons had a significantly (49%) higher mean baseline cA-TAT proteolysis rate than those maintaining calcium homeostasis, suggesting that the unknown protease(s) cleaving cA-TAT may influence DCD susceptibility. Overall, the results indicate that excitotoxic glutamate triggers the activation of calpain-independent neuronal protease activity prior to the simultaneous loss of calcium homeostasis and mitochondrial bioenergetic function.
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Affiliation(s)
- Brian M. Polster
- Buck Institute for Age Research, Novato, CA 94945, USA;
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Correspondence: ; Tel.: +1-410-706-3418
| | - Karla A. Mark
- Buck Institute for Age Research, Novato, CA 94945, USA;
| | - Rafael Arze
- Biosearch Technologies, Inc., Novato, CA 94949, USA; (R.A.); (D.H.)
| | - Derek Hudson
- Biosearch Technologies, Inc., Novato, CA 94949, USA; (R.A.); (D.H.)
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Abbotts R, Stojanovic L, Topper MJ, Polster BM, Baylin SB, Rassool FV. Abstract 5593: DNMT inhibitor induces NSCLC inflammasome signaling and mitochondrial dysfunction, producing to DSB repair defects and PARP inhibitor sensitivity. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-5593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
DNA methyltransferase inhibitors (DNMTis) modulate genome-wide methylation patterns, previously linked by our group to downregulation of DNA double strand break repair (DSBR) that sensitizes non-small cell lung cancer (NSCLC) to poly(ADP-ribose) polymerase inhibitors (PARPis). DNMTi hypomethylation of endogenous retroviral (ERV) elements produces cytosolic aggregation of double-stranded RNA (dsRNA) that activates antiviral interferon (IFN) and inflammasome signaling. Accordingly, DNMTi treatment of NSCLC cell lines (A549, H460) increases expression of 1) multiple ERV transcripts; 2) dsRNA sensors RIG-I and MDA5; 3) downstream mitochondrial antiviral signaling protein (MAVS); 4) MAVS-activated antiviral kinases (TBK1, IKKα/β) and transcriptional regulators (IRF3/7, NFκB); and 5) IFNβ and IFN-stimulated genes (ISGs).
A second mechanism of cellular antiviral signaling is STING (stimulator of interferon genes) activation triggered by cytosolic dsDNA. Following DNMTi treatment, we observe mitochondrial dysfunction including impairment of oxidative phosphorylation, reactive oxygen species generation, and reduced mitochondrial membrane potential. This dysfunction is associated with increased mitochondrial DNA (mtDNA) damage and accumulation of cytosolic mtDNA, leading to increased STING expression and IFN activation that can be abrogated by siSTING or IKK inhibition. Treatment with PARPi, which activates STING via cytosolic accumulation of damaged nuclear DNA, further enhances DNMTi-induced IFN signaling.
We previously linked IFN activation to DSBR downregulation in breast and ovarian cancer, and now present TCGA analysis in NSCLC indicating a similar negative correlation, corroborated by reduced DSBR in NSCLC cell lines after IFNβ treatment. Computational interrogation indicates multiple DSBR promoters contain IFN-stimulated response elements (ISREs), including potential negative regulators, that may account for these findings. Notably, we find that precise patterns of immune activation may be TP53 dependent: NSCLC cell lines with missense mutations (H23, H441, H1115), as observed in ~30% patients, exhibit increased NFκB inflammasome signaling and decreased IFN activation compared to wildtype (A549, H460). TP53 mutation is associated with significantly reduced baseline STING expression, potentially affording a more robust DNMTi treatment response; accordingly, TP53-mutant NSCLC cells exhibit significantly greater sensitivity to DNMTi/PARPi.
Our new data expands on our published work to further understanding of novel mechanisms of 1) inflammasome induction and 2) mitochondrial dysfunction through which DNMTis activate cellular antiviral signaling and downregulate DSBR to induce PARPi sensitivity in NSCLC. We also identify TP53 as a possible biomarker for future personalization of DNMTi therapy.
Citation Format: Rachel Abbotts, Lora Stojanovic, Michael J. Topper, Brian M. Polster, Stephen B. Baylin, Feyruz V. Rassool. DNMT inhibitor induces NSCLC inflammasome signaling and mitochondrial dysfunction, producing to DSB repair defects and PARP inhibitor sensitivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5593.
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Macklin BL, Lin YY, Emmerich K, Wisniewski E, Polster BM, Konstantopoulos K, Mumm JS, Gerecht S. Intrinsic epigenetic control of angiogenesis in induced pluripotent stem cell-derived endothelium regulates vascular regeneration. NPJ Regen Med 2022; 7:28. [PMID: 35551465 PMCID: PMC9098630 DOI: 10.1038/s41536-022-00223-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 04/14/2022] [Indexed: 11/17/2022] Open
Abstract
Human-induced pluripotent stem cell-derived endothelial cells (iECs) provide opportunities to study vascular development and regeneration, develop cardiovascular therapeutics, and engineer model systems for drug screening. The differentiation and characterization of iECs are well established; however, the mechanisms governing their angiogenic phenotype remain unknown. Here, we aimed to determine the angiogenic phenotype of iECs and the regulatory mechanism controlling their regenerative capacity. In a comparative study with HUVECs, we show that iECs increased expression of vascular endothelial growth factor receptor 2 (VEGFR2) mediates their highly angiogenic phenotype via regulation of glycolysis enzymes, filopodia formation, VEGF mediated migration, and robust sprouting. We find that the elevated expression of VEGFR2 is epigenetically regulated via intrinsic acetylation of histone 3 at lysine 27 by histone acetyltransferase P300. Utilizing a zebrafish xenograft model, we demonstrate that the ability of iECs to promote the regeneration of the amputated fin can be modulated by P300 activity. These findings demonstrate how the innate epigenetic status of iECs regulates their phenotype with implications for their therapeutic potential.
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Affiliation(s)
- Bria L Macklin
- Department of Chemical and Biomolecular Engineering, The Institute for NanoBioTechnology, Physical Sciences-Oncology Center, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Ying-Yu Lin
- Department of Chemical and Biomolecular Engineering, The Institute for NanoBioTechnology, Physical Sciences-Oncology Center, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Kevin Emmerich
- Department of Ophthalmology, Wilmer Eye Institute and McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Emily Wisniewski
- Department of Chemical and Biomolecular Engineering, The Institute for NanoBioTechnology, Physical Sciences-Oncology Center, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Konstantinos Konstantopoulos
- Department of Chemical and Biomolecular Engineering, The Institute for NanoBioTechnology, Physical Sciences-Oncology Center, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Jeff S Mumm
- Department of Ophthalmology, Wilmer Eye Institute and McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Sharon Gerecht
- Department of Chemical and Biomolecular Engineering, The Institute for NanoBioTechnology, Physical Sciences-Oncology Center, Johns Hopkins University, Baltimore, MD, 21218, USA. .,Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
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10
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Shimada BK, Boyman L, Huang W, Zhu J, Yang Y, Chen F, Kane MA, Yadava N, Zou L, Lederer WJ, Polster BM, Chao W. Pyruvate-Driven Oxidative Phosphorylation is Downregulated in Sepsis-Induced Cardiomyopathy: A Study of Mitochondrial Proteome. Shock 2022; 57:553-564. [PMID: 34506367 PMCID: PMC8904652 DOI: 10.1097/shk.0000000000001858] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 07/28/2021] [Accepted: 09/02/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Sepsis-induced cardiomyopathy (SIC) is a major contributing factor for morbidity and mortality in sepsis. Accumulative evidence has suggested that cardiac mitochondrial oxidative phosphorylation is attenuated in sepsis, but the underlying molecular mechanisms remain incompletely understood. METHODS Adult male mice of 9 to 12 weeks old were subjected to sham or cecal ligation and puncture procedure. Echocardiography in vivo and Langendorff-perfused hearts were used to assess cardiac function 24 h after the procedures. Unbiased proteomics analysis was performed to profile mitochondrial proteins in the hearts of both sham and SIC mice. Seahorse respirator technology was used to evaluate oxygen consumption in purified mitochondria. RESULTS Of the 665 mitochondrial proteins identified in the proteomics assay, 35 were altered in septic mice. The mitochondrial remodeling involved various energy metabolism pathways including subunits of the electron transport chain, fatty acid catabolism, and carbohydrate oxidative metabolism. We also identified a significant increase of pyruvate dehydrogenase (PDH) kinase 4 (PDK4) and inhibition of PDH activity in septic hearts. Furthermore, compared to sham mice, mitochondrial oxygen consumption of septic mice was significantly reduced when pyruvate was provided as a substrate. However, it was unchanged when PDH was bypassed by directly supplying the Complex I substrate NADH, or by using the Complex II substrate succinate, or using Complex IV substrate, or by providing the beta-oxidation substrate palmitoylcarnitine, neither of which require PDH for mitochondrial oxygen consumption. CONCLUSIONS These data demonstrate a broad mitochondrial protein remodeling, PDH inactivation and impaired pyruvate-fueled oxidative phosphorylation during SIC, and provide a molecular framework for further exploration.
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Affiliation(s)
- Briana K. Shimada
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
| | - Liron Boyman
- The Department of Physiology and Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland
| | - Jing Zhu
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
| | - Yang Yang
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
| | - Fengqian Chen
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland
| | - Nagendra Yadava
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
| | - Lin Zou
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
| | - W. Jonathan Lederer
- The Department of Physiology and Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Brian M. Polster
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
| | - Wei Chao
- Translational Research Program, Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, Baltimore, Maryland
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11
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Bordt EA, Zhang N, Waddell J, Polster BM. The Non-Specific Drp1 Inhibitor Mdivi-1 Has Modest Biochemical Antioxidant Activity. Antioxidants (Basel) 2022; 11:antiox11030450. [PMID: 35326100 PMCID: PMC8944504 DOI: 10.3390/antiox11030450] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 02/16/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial division inhibitor-1 (mdivi-1), a non-specific inhibitor of Drp1-dependent mitochondrial fission, is neuroprotective in numerous preclinical disease models. These include rodent models of Alzheimer’s disease and ischemic or traumatic brain injury. Among its Drp1-independent actions, the compound was found to suppress mitochondrial Complex I-dependent respiration but with less resultant mitochondrial reactive oxygen species (ROS) emission compared with the classical Complex I inhibitor rotenone. We employed two different methods of quantifying Trolox-equivalent antioxidant capacity (TEAC) to test the prediction that mdivi-1 can directly scavenge free radicals. Mdivi-1 exhibited moderate antioxidant activity in the 2,2′-azinobis (3-ethylbenzothiazoline 6-sulfonate) (ABTS) assay. Half-maximal ABTS radical depletion was observed at ~25 μM mdivi-1, equivalent to that achieved by ~12.5 μM Trolox. Mdivi-1 also showed antioxidant activity in the α, α-diphenyl-β-picrylhydrazyl (DPPH) assay. However, mdivi-1 exhibited a reduced capacity to deplete the DPPH radical, which has a more sterically hindered radical site compared with ABTS, with 25 μM mdivi-1 displaying only 0.8 μM Trolox equivalency. Both assays indicate that mdivi-1 possesses biochemical antioxidant activity but with modest potency relative to the vitamin E analog Trolox. Future studies are needed to evaluate whether the ability of mdivi-1 to directly scavenge free radicals contributes to its mechanisms of neuroprotection.
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Affiliation(s)
- Evan A. Bordt
- Center for Shock, Trauma and Anesthesiology Research, Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
- Lurie Center for Autism, Department of Pediatrics, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA 02129, USA
- Correspondence: (E.A.B.); (B.M.P.); Tel.: +01-617-643-4351 (E.A.B.); +01-410-706-3418 (B.M.P.)
| | - Naibo Zhang
- Center for Shock, Trauma and Anesthesiology Research, Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jaylyn Waddell
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Brian M. Polster
- Center for Shock, Trauma and Anesthesiology Research, Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Correspondence: (E.A.B.); (B.M.P.); Tel.: +01-617-643-4351 (E.A.B.); +01-410-706-3418 (B.M.P.)
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12
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Song H, Polster BM, Thompson LP. Chronic hypoxia alters cardiac mitochondrial complex protein expression and activity in fetal guinea pigs in a sex-selective manner. Am J Physiol Regul Integr Comp Physiol 2021; 321:R912-R924. [PMID: 34730023 PMCID: PMC8714812 DOI: 10.1152/ajpregu.00004.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 10/22/2021] [Accepted: 10/22/2021] [Indexed: 11/22/2022]
Abstract
We hypothesize that intrauterine hypoxia (HPX) alters the mitochondrial phenotype in fetal hearts contributing to developmental programming. Pregnant guinea pigs were exposed to normoxia (NMX) or hypoxia (HPX, 10.5% O2), starting at early [25 days (25d), 39d duration] or late gestation (50d, 14d duration). Near-term (64d) male and female fetuses were delivered by hysterotomy from anesthetized sows, and body/organ weights were measured. Left ventricles of fetal hearts were excised and frozen for measurement of expression of complex (I-V) subunits, fusion (Mfn2/OPA1) and fission (DRP1/Fis1) proteins, and enzymatic rates of I and IV from isolated mitochondrial proteins. Chronic HPX decreased fetal body weight and increased relative placenta weight regardless of timing. Early-onset HPX increased I, III, and V subunit levels, increased complex I but decreased IV activities in males but not females (all P < 0.05). Late-onset HPX decreased (P < 0.05) I, III, and V levels in both sexes but increased I and decreased IV activities in males only. Both HPX conditions decreased cardiac mitochondrial DNA content in males only. Neither early- nor late-onset HPX had any effect on Mfn2 levels but increased OPA1 in both sexes. Both HPX treatments increased DRP1/Fis1 levels in males. In females, early-onset HPX increased DRP1 with no effect on Fis1, whereas late-onset HPX increased Fis1 with no effect on DRP1. We conclude that both early- and late-onset HPX disrupts the expression/activities of select complexes that could reduce respiratory efficiency and shifts dynamics toward fission in fetal hearts. Thus, intrauterine HPX disrupts the mitochondrial phenotype predominantly in male fetal hearts, potentially altering cardiac metabolism and predisposing the offspring to heart dysfunction.
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Affiliation(s)
- Hong Song
- Department of Obstetrics, Gynecology and Reproductive Sciences, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Loren P Thompson
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, School of Medicine, University of Maryland, Baltimore, Maryland
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13
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Lin BC, Phung TH, Higgins NR, Greenslade JE, Prado MA, Finley D, Karbowski M, Polster BM, Monteiro MJ. ALS/FTD mutations in UBQLN2 are linked to mitochondrial dysfunction through loss-of-function in mitochondrial protein import. Hum Mol Genet 2021; 30:1230-1246. [PMID: 33891006 PMCID: PMC8212775 DOI: 10.1093/hmg/ddab116] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 01/12/2023] Open
Abstract
UBQLN2 mutations cause amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD), but the pathogenic mechanisms by which they cause disease remain unclear. Proteomic profiling identified 'mitochondrial proteins' as comprising the largest category of protein changes in the spinal cord (SC) of the P497S UBQLN2 mouse model of ALS/FTD. Immunoblots confirmed P497S animals have global changes in proteins predictive of a severe decline in mitochondrial health, including oxidative phosphorylation (OXPHOS), mitochondrial protein import and network dynamics. Functional studies confirmed mitochondria purified from the SC of P497S animals have age-dependent decline in nearly all steps of OXPHOS. Mitochondria cristae deformities were evident in spinal motor neurons of aged P497S animals. Knockout (KO) of UBQLN2 in HeLa cells resulted in changes in mitochondrial proteins and OXPHOS activity similar to those seen in the SC. KO of UBQLN2 also compromised targeting and processing of the mitochondrial import factor, TIMM44, resulting in accumulation in abnormal foci. The functional OXPHOS deficits and TIMM44-targeting defects were rescued by reexpression of WT UBQLN2 but not by ALS/FTD mutant UBQLN2 proteins. In vitro binding assays revealed ALS/FTD mutant UBQLN2 proteins bind weaker with TIMM44 than WT UBQLN2 protein, suggesting that the loss of UBQLN2 binding may underlie the import and/or delivery defect of TIMM44 to mitochondria. Our studies indicate a potential key pathogenic disturbance in mitochondrial health caused by UBQLN2 mutations.
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Affiliation(s)
- Brian C Lin
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Trong H Phung
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nicole R Higgins
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jessie E Greenslade
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Mariusz Karbowski
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian M Polster
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mervyn J Monteiro
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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14
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Lee H, Jiang X, Perwaiz I, Yu P, Wang J, Wang Y, Hüttemann M, Felder RA, Sibley DR, Polster BM, Rozyyev S, Armando I, Yang Z, Qu P, Jose PA. Dopamine D 5 receptor-mediated decreases in mitochondrial reactive oxygen species production are cAMP and autophagy dependent. Hypertens Res 2021; 44:628-641. [PMID: 33820956 PMCID: PMC8369611 DOI: 10.1038/s41440-021-00646-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 11/10/2019] [Accepted: 12/03/2019] [Indexed: 01/31/2023]
Abstract
Overproduction of reactive oxygen species (ROS) plays an important role in the pathogenesis of hypertension. The dopamine D5 receptor (D5R) is known to decrease ROS production, but the mechanism is not completely understood. In HEK293 cells overexpressing D5R, fenoldopam, an agonist of the two D1-like receptors, D1R and D5R, decreased the production of mitochondria-derived ROS (mito-ROS). The fenoldopam-mediated decrease in mito-ROS production was mimicked by Sp-cAMPS but blocked by Rp-cAMPS. In human renal proximal tubule cells with DRD1 gene silencing to eliminate the confounding effect of D1R, fenoldopam still decreased mito-ROS production. By contrast, Sch23390, a D1R and D5R antagonist, increased mito-ROS production in the absence of D1R, D5R is constitutively active. The fenoldopam-mediated inhibition of mito-ROS production may have been related to autophagy because fenoldopam increased the expression of the autophagy hallmark proteins, autophagy protein 5 (ATG5), and the microtubule-associated protein 1 light chain (LC)3-II. In the presence of chloroquine or spautin-1, inhibitors of autophagy, fenoldopam further increased ATG5 and LC3-II expression, indicating an important role of D5R in the positive regulation of autophagy. However, when autophagy was inhibited, fenoldopam was unable to inhibit ROS production. Indeed, the levels of these autophagy hallmark proteins were decreased in the kidney cortices of Drd5-/- mice. Moreover, ROS production was increased in mitochondria isolated from the kidney cortices of Drd5-/- mice, relative to Drd5+/+ littermates. In conclusion, D5R-mediated activation of autophagy plays a role in the D5R-mediated inhibition of mito-ROS production in the kidneys.
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Affiliation(s)
- Hewang Lee
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA,Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China,Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA,Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Xiaoliang Jiang
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Imran Perwaiz
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Peiying Yu
- Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - Jin Wang
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Ying Wang
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics and Cardiovascular Research Institute, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Robin A. Felder
- Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, VA, USA
| | - David R. Sibley
- Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Brian M. Polster
- Department of Anesthesiology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Selim Rozyyev
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA
| | - Ines Armando
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA,Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - Zhiwei Yang
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Peng Qu
- Institute of Heart and Vessel Diseases, Affiliated Second Hospital, Dalian Medical University, Dalian, China
| | - Pedro A. Jose
- Department of Medicine, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA,Division of Nephrology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, MD, USA,Center for Molecular Physiology Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC, USA,Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA,Department of Pharmacology and Physiology, School of Medicine & Health Sciences, George Washington University, Washington, DC, USA
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15
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Oshima Y, Cartier E, Boyman L, Verhoeven N, Polster BM, Huang W, Kane M, Lederer WJ, Karbowski M. Parkin-independent mitophagy via Drp1-mediated outer membrane severing and inner membrane ubiquitination. J Cell Biol 2021; 220:211984. [PMID: 33851959 PMCID: PMC8050842 DOI: 10.1083/jcb.202006043] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 02/02/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
Here, we report that acute reduction in mitochondrial translation fidelity (MTF) causes ubiquitination of the inner mitochondrial membrane (IMM) proteins, including TRAP1 and CPOX, which occurs selectively in mitochondria with a severed outer mitochondrial membrane (OMM). Ubiquitinated IMM recruits the autophagy machinery. Inhibiting autophagy leads to increased accumulation of mitochondria with severed OMM and ubiquitinated IMM. This process occurs downstream of the accumulation of cytochrome c/CPOX in a subset of mitochondria heterogeneously distributed throughout the cell (“mosaic distribution”). Formation of mosaic mitochondria, OMM severing, and IMM ubiquitination require active mitochondrial translation and mitochondrial fission, but not the proapoptotic proteins Bax and Bak. In contrast, in Parkin-overexpressing cells, MTF reduction does not lead to the severing of the OMM or IMM ubiquitination, but it does induce Drp1-independent ubiquitination of the OMM. Furthermore, high–cytochrome c/CPOX mitochondria are preferentially targeted by Parkin, indicating that in the context of reduced MTF, they are mitophagy intermediates regardless of Parkin expression. In sum, Parkin-deficient cells adapt to mitochondrial proteotoxicity through a Drp1-mediated mechanism that involves the severing of the OMM and autophagy targeting ubiquitinated IMM proteins.
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Affiliation(s)
- Yumiko Oshima
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
| | - Etienne Cartier
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD
| | - Nicolas Verhoeven
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD
| | - Maureen Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD
| | - Mariusz Karbowski
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
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16
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Kim MS, Gernapudi R, Cedeño YC, Polster BM, Martinez R, Shapiro P, Kesari S, Nurmemmedov E, Passaniti A. Targeting breast cancer metabolism with a novel inhibitor of mitochondrial ATP synthesis. Oncotarget 2020; 11:3863-3885. [PMID: 33196708 PMCID: PMC7597410 DOI: 10.18632/oncotarget.27743] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 08/24/2020] [Indexed: 01/17/2023] Open
Abstract
Inhibitors of mitochondrial respiration and ATP synthesis may promote the selective killing of respiration-competent cancer cells that are critical for tumor progression. We previously reported that CADD522, a small molecule inhibitor of the RUNX2 transcription factor, has potential for breast cancer treatment. In the current study, we show that CADD522 inhibits mitochondrial oxidative phosphorylation by decreasing the mitochondrial oxygen consumption rate (OCR) and ATP production in human breast cancer cells in a RUNX2-independent manner. The enzyme activity of mitochondrial ATP synthase was inhibited by CADD522 treatment. Importantly, results from cellular thermal shift assays that detect drug-induced protein stabilization revealed that CADD522 interacts with both α and β subunits of the F1-ATP synthase complex. Differential scanning fluorimetry also demonstrated interaction of α subunits of the F1-ATP synthase to CADD522. These results suggest that CADD522 might target the enzymatic F1 subunits in the ATP synthase complex. CADD522 increased the levels of intracellular reactive oxygen species (ROS), which was prevented by MitoQ, a mitochondria-targeted antioxidant, suggesting that cancer cells exposed to CADD522 may elevate ROS from mitochondria. CADD522-increased mitochondrial ROS levels were enhanced by exogenously added pro-oxidants such as hydrogen peroxide or tert-butyl hydroperoxide. Conversely, CADD522-mediated cell growth inhibition was blocked by N-acetyl-l-cysteine, a general ROS scavenger. Therefore, CADD522 may exert its antitumor activity by increasing mitochondrial driven cellular ROS levels. Collectively, our data suggest in vitro proof-of-concept that supports inhibition of mitochondrial ATP synthase and ROS generation as contributors to the effectiveness of CADD522 in suppression of tumor growth.
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Affiliation(s)
- Myoung Sook Kim
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
- The Marlene & Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Ramkishore Gernapudi
- Department of Biochemistry & Molecular Biology and Program in Molecular Medicine, Baltimore, MD, USA
- The Marlene & Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | | | - Brian M. Polster
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Research Health Scientist, The Veteran's Health Administration Research & Development Service (VAMHCS), Baltimore, MD, USA
| | - Ramon Martinez
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, USA
| | - Paul Shapiro
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, USA
| | - Santosh Kesari
- John Wayne Cancer Institute and Pacific Neuroscience Institute at Providence Saint John’s Health Center, Santa Monica, CA, USA
| | - Elmar Nurmemmedov
- John Wayne Cancer Institute and Pacific Neuroscience Institute at Providence Saint John’s Health Center, Santa Monica, CA, USA
| | - Antonino Passaniti
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Biochemistry & Molecular Biology and Program in Molecular Medicine, Baltimore, MD, USA
- The Marlene & Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Research Health Scientist, The Veteran's Health Administration Research & Development Service (VAMHCS), Baltimore, MD, USA
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17
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Makarevich O, Sabirzhanov B, Aubrecht TG, Glaser EP, Polster BM, Henry RJ, Faden AI, Stoica BA. Mithramycin selectively attenuates DNA-damage-induced neuronal cell death. Cell Death Dis 2020; 11:587. [PMID: 32719328 PMCID: PMC7385624 DOI: 10.1038/s41419-020-02774-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/06/2020] [Accepted: 07/10/2020] [Indexed: 12/15/2022]
Abstract
DNA damage triggers cell death mechanisms contributing to neuronal loss and cognitive decline in neurological disorders, including traumatic brain injury (TBI), and as a side effect of chemotherapy. Mithramycin, which competitively targets chromatin-binding sites of specificity protein 1 (Sp1), was used to examine previously unexplored neuronal cell death regulatory mechanisms via rat primary neurons in vitro and after TBI in mice (males). In primary neurons exposed to DNA-damage-inducing chemotherapy drugs in vitro we showed that DNA breaks sequentially initiate DNA-damage responses, including phosphorylation of ATM, H2AX and tumor protein 53 (p53), transcriptional activation of pro-apoptotic BH3-only proteins, and mitochondrial outer membrane permeabilization (MOMP), activating caspase-dependent and caspase-independent intrinsic apoptosis. Mithramycin was highly neuroprotective in DNA-damage-dependent neuronal cell death, inhibiting chemotherapeutic-induced cell death cascades downstream of ATM and p53 phosphorylation/activation but upstream of p53-induced expression of pro-apoptotic molecules. Mithramycin reduced neuronal upregulation of BH3-only proteins and mitochondrial dysfunction, attenuated caspase-3/7 activation and caspase substrates' cleavage, and limited c-Jun activation. Chromatin immunoprecipitation indicated that mithramycin attenuates Sp1 binding to pro-apoptotic gene promoters without altering p53 binding suggesting it acts by removing cofactors required for p53 transactivation. In contrast, the DNA-damage-independent neuronal death models displayed caspase initiation in the absence of p53/BH3 activation and were not protected even when mithramycin reduced caspase activation. Interestingly, experimental TBI triggers a multiplicity of neuronal death mechanisms. Although markers of DNA-damage/p53-dependent intrinsic apoptosis are detected acutely in the injured cortex and are attenuated by mithramycin, these processes may play a reduced role in early neuronal death after TBI, as caspase-dependent mechanisms are repressed in mature neurons while other, mithramycin-resistant mechanisms are active. Our data suggest that Sp1 is required for p53-mediated transactivation of neuronal pro-apoptotic molecules and that mithramycin may attenuate neuronal cell death in conditions predominantly involving DNA-damage-induced p53-dependent intrinsic apoptosis.
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Affiliation(s)
- Oleg Makarevich
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Boris Sabirzhanov
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Taryn G Aubrecht
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ethan P Glaser
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Brian M Polster
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Rebecca J Henry
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Alan I Faden
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Bogdan A Stoica
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
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18
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Jaber SM, Yadava N, Polster BM. Mapping mitochondrial respiratory chain deficiencies by respirometry: Beyond the Mito Stress Test. Exp Neurol 2020; 328:113282. [PMID: 32165258 DOI: 10.1016/j.expneurol.2020.113282] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/01/2020] [Accepted: 03/08/2020] [Indexed: 02/06/2023]
Abstract
Cell-based respirometers, such as the Seahorse Extracellular Flux Analyzer, are valuable tools to assess the functionality of mitochondria within adherent neurons, as well as other cell types. The Mito Stress Test is the most frequently employed protocol of drug additions to evaluate mitochondrial bioenergetic function. Sequential exposure of cells to an ATP synthase inhibitor such as oligomycin and an uncoupler such as FCCP cause changes in oxygen consumption rate that allow estimation of the cellular efficiency and capacity for mitochondrial ATP synthesis. While a useful first step in assessing whether an experimental treatment or genetic manipulation affects mitochondrial energetics, the Mito Stress Test does not identify specific sites of altered respiratory chain function. This article discusses limitations of the Mito Stress Test, proposes a refined protocol for comparing cell populations that requires independent drug titrations at multiple cell densities, and describes a stepwise series of respirometry-based assays that "map" locations of electron transport deficiency. These include strategies to test for cytochrome c release, to probe the functionality of specific electron transport chain complexes within intact or permeabilized cells, and to measure NADH oxidation by the linked activity of Complexes I, III, and IV. To illustrate utility, we show that although UK5099 and ABT-737 each decrease the spare respiratory capacity of cortical neurons, the stepwise assays reveal different underlying mechanisms consistent with their established drug targets: deficient Complex I substrate supply induced by the mitochondrial pyruvate carrier inhibitor UK5099 and cytochrome c release induced by the anti-apoptotic BCL-2 family protein inhibitor ABT-737.
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Affiliation(s)
- Sausan M Jaber
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nagendra Yadava
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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19
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Kim MS, Gernapudi R, Cedeno YC, Polster BM, Girnun GD, Passaniti A. Abstract 794: Inhibition of mitochondrial metabolism by a novel agent targeting RUNX2-DNA binding in breast cancer. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The RUNX2 transcription factor promotes breast cancer growth and metastasis through interactions with a variety of cofactors that activate or repress target genes. RUNX2 knockdown decreases expression levels of glycolytic genes such as LDHA, HK2 and GLUT-1, but upregulates PDHA1 mRNA level and enzymatic activity, which is consistent with lower glycolytic potential. Using a direct computer-assisted drug discovery (CADD) approach, we identified CADD522 as a small molecule that inhibits the RUNX2-DNA binding, transcriptional activity of RUNX2, and expression of RUNX2 target genes. We also observed that CADD522 inhibits breast cancer growth and metastasis using in vitro and in vivo tumor models. RUNX2-activated glucose utilization and GLUT-1 levels were also reduced by CADD522. New data also define CADD522 as a potential antitumor agent that downregulates the levels of metabolites in the TCA cycle and inhibits mitochondrial oxygen consumption rates. Our results support the observations that CADD522 could regulate cellular metabolism through modulation of both glycolytic metabolism and mitochondrial oxidative phosphorylation. To address the mechanisms by which CADD522 exerts its inhibitory effects on mitochondrial metabolism, we performed RNA-Sequencing analysis in breast cancer cells and identified several specific molecular signatures that determine cellular response to RUNX2 and CADD522. Further pathway changes in mitochondrial function as well as validation of differentially expressed genes that play critical roles in mitochondrial metabolism are under investigation.
Citation Format: Myoung Sook Kim, Ramkishore Gernapudi, Yessenia C. Cedeno, Brian M. Polster, Geoffrey D. Girnun, Antonino Passaniti. Inhibition of mitochondrial metabolism by a novel agent targeting RUNX2-DNA binding in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 794.
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20
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Thompson LP, Song H, Polster BM. Fetal Programming and Sexual Dimorphism of Mitochondrial Protein Expression and Activity of Hearts of Prenatally Hypoxic Guinea Pig Offspring. Oxid Med Cell Longev 2019; 2019:7210249. [PMID: 31249648 PMCID: PMC6589217 DOI: 10.1155/2019/7210249] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/12/2019] [Accepted: 05/20/2019] [Indexed: 12/15/2022]
Abstract
Chronic intrauterine hypoxia is a programming stimulus of cardiovascular dysfunction. While the fetal heart adapts to the reduced oxygenation, the offspring heart becomes vulnerable to subsequent metabolic challenges as an adult. Cardiac mitochondria are key organelles responsible for an efficient energy supply but are subject to damage under hypoxic conditions. We propose that intrauterine hypoxia alters mitochondrial function as an underlying programming mechanism of contractile dysfunction in the offspring. Indices of mitochondrial function such as mitochondrial DNA content, Complex (C) I-V expression, and CI/CIV enzyme activity were measured in hearts of male and female offspring at 90 days old exposed to prenatal hypoxia (10.5% O2) for 14 d prior to term (65 d). Both left ventricular tissue and cardiomyocytes exhibited decreased mitochondrial DNA content, expression of CIV, and CI/CIV activity in male hearts. In female cardiomyocytes, hypoxia had no effect on protein expression of CI-CV nor on CI/CIV activity. This study suggests that chronic intrauterine hypoxia alters the intrinsic properties of select respiratory complexes as a programming mechanism of cardiac dysfunction in the offspring. Sex differences in mitochondrial function may underlie the increased vulnerability of age-matched males compared to females in cardiovascular disease and heart failure.
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Affiliation(s)
- Loren P. Thompson
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland, Baltimore, School of Medicine, 655 W. Baltimore St., Baltimore, MD 21201, USA
| | - Hong Song
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland, Baltimore, School of Medicine, 655 W. Baltimore St., Baltimore, MD 21201, USA
| | - Brian M. Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, University of Maryland, Baltimore, School of Medicine, 655 W. Baltimore St., Baltimore, MD 21201, USA
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21
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Thompson LP, Chen L, Polster BM, Pinkas G, Song H. Prenatal hypoxia impairs cardiac mitochondrial and ventricular function in guinea pig offspring in a sex-related manner. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1232-R1241. [PMID: 30365351 DOI: 10.1152/ajpregu.00224.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Adverse intrauterine conditions cause fetal growth restriction and increase the risk of adult cardiovascular disease. We hypothesize that intrauterine hypoxia impairs fetal heart function, is sustained after birth, and manifests as both cardiac and mitochondrial dysfunction in offspring guinea pigs (GPs). Pregnant GPs were exposed to 10.5% O2 (HPX) at 50 days of gestation (full term = 65 days) or normoxia (NMX) for the duration of the pregnancy. Pups were allowed to deliver vaginally and raised in a NMX environment. At 90 days of age, mean arterial pressure (MAP) was measured in anesthetized GPs. NMX and prenatally HPX offspring underwent echocardiographic imaging for in vivo measurement of left ventricular cardiac morphology and function, and O2 consumption rates and complex IV enzyme activity were measured from isolated cardiomyocytes and mitochondria, respectively. Prenatal HPX increased ( P < 0.01) MAP (52.3 ± 1.3 and 58.4 ± 1.1 mmHg in NMX and HPX, respectively) and decreased ( P < 0.05) stroke volume (439.8 ± 54.5 and 289.4 ± 15.8 μl in NMX and HPX, respectively), cardiac output (94.4 ± 11.2 and 67.3 ± 3.8 ml/min in NMX and HPX, respectively), ejection fraction, and fractional shortening in male, but not female, GPs. HPX had no effect on left ventricular wall thickness or end-diastolic volume in either sex. HPX reduced mitochondrial maximal respiration and respiratory reserve capacity and complex IV activity rates in hearts of male, but not female, GPs. Prenatal HPX is a programming stimulus that increases MAP and decreases cardiac and mitochondrial function in male offspring. Sex-related differences in the contractile and mitochondrial responses suggest that female GPs are protected from cardiovascular programming of prenatal HPX.
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Affiliation(s)
- Loren P Thompson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine , Baltimore, Maryland
| | - Ling Chen
- Department of Physiology and Medicine, University of Maryland School of Medicine , Baltimore, Maryland
| | - Brian M Polster
- Department of Anesthesiology, University of Maryland School of Medicine , Baltimore, Maryland
| | - Gerard Pinkas
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine , Baltimore, Maryland
| | - Hong Song
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine , Baltimore, Maryland
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22
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Jaber SM, Bordt EA, Bhatt NM, Lewis DM, Gerecht S, Fiskum G, Polster BM. Sex differences in the mitochondrial bioenergetics of astrocytes but not microglia at a physiologically relevant brain oxygen tension. Neurochem Int 2018; 117:82-90. [PMID: 28888963 PMCID: PMC5839942 DOI: 10.1016/j.neuint.2017.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/14/2017] [Accepted: 09/05/2017] [Indexed: 11/22/2022]
Abstract
Biological sex is thought to influence mitochondrial bioenergetic function. Previous respiration measurements examining brain mitochondrial sex differences were made at atmospheric oxygen using isolated brain mitochondria. Oxygen is 160 mm Hg (21%) in the atmosphere, while the oxygen tension in the brain generally ranges from ∼5 to 45 mm Hg (∼1-6% O2). This study tested the hypothesis that sex and/or brain physiological oxygen tension influence the mitochondrial bioenergetic properties of primary rat cortical astrocytes and microglia. Oxygen consumption was measured with a Seahorse XF24 cell respirometer in an oxygen-controlled environmental chamber. Strikingly, male astrocytes had a higher maximal respiration than female astrocytes when cultured and assayed at 3% O2. Three percent O2 yielded a low physiological dissolved O2 level of ∼1.2% (9.1 mm Hg) at the cell monolayer during culture and 1.2-3.0% O2 during assays. No differences in bioenergetic parameters were observed between male and female astrocytes at 21% O2 (dissolved O2 of ∼19.7%, 150 mm Hg during culture) or between either of these cell populations and female astrocytes at 3% O2. In contrast to astrocytes, microglia showed no sex differences in mitochondrial bioenergetic parameters at either oxygen level, regardless of whether they were non-stimulated or activated to a proinflammatory state. There were also no O2- or sex-dependent differences in proinflammatory TNF-α or IL-1β cytokine secretion measured at 18 h activation. Overall, results reveal an intriguing sex variance in astrocytic maximal respiration that requires additional investigation. Findings also demonstrate that sex differences can be masked by conducting experiments at non-physiological O2.
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Affiliation(s)
- Sausan M Jaber
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Evan A Bordt
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Niraj M Bhatt
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Daniel M Lewis
- Department of Chemical and Biomolecular Engineering, Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Shaffer Hall 200C, Baltimore, MD 21218, USA
| | - Sharon Gerecht
- Department of Chemical and Biomolecular Engineering, Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Shaffer Hall 200C, Baltimore, MD 21218, USA; Department of Materials Science and Engineering, Johns Hopkins University, 3400 North Charles Street, Shaffer Hall 200C, Baltimore, MD 21218, USA
| | - Gary Fiskum
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Brian M Polster
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA.
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23
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Abstract
In Part II of this Special Issue on "Mitochondria in the Nervous System: From Health to Disease", the editors bring together more reviews and original articles from researchers in the field of mitochondrial metabolism in the healthy and diseased nervous system. Subjects span from basic mitochondrial physiology to papers on mitochondrial dynamics and to those altered states of the nervous system that can be considered "mitopathologies". Finally, a few papers approach aspects of mitochondrial biology linked to the feasibility and validity of a mitochondrial therapy.
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Affiliation(s)
- Maria Teresa Carrì
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133, Rome, Italy; Fondazione Santa Lucia IRCCS, Via Ardeatina 306, Rome, Italy.
| | - Brian M Polster
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Philip M Beart
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, 3010, Australia
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24
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Abstract
In Part I of this Special Issue on "Mitochondria in the Nervous System: From Health to Disease", the editors bring together contributions from experts in brain mitochondrial research to provide an up-to-date overview of mitochondrial functioning in physiology and pathology. The issue provides cutting edge reviews on classical areas of mitochondrial biology that include energy substrate utilization, calcium handling, mitochondria-endoplasmic reticulum communication, and cell death regulation. Additional reviews and original research articles touch upon key mitochondrial defects seen across multiple neurodegenerative conditions, including fragmentation, loss of respiratory capacity, calcium overload, elevated reactive oxygen species generation, perturbed NAD+ metabolism, altered protein acetylation, and compromised mitophagy. Emerging links between the genetics of neurodegenerative disorders and disruption in mitochondrial function are discussed, and a new mouse model of Complex I deficiency is described. Finally, novel ways to rescue mitochondrial structure and function in acute and chronic brain injury are explored.
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Affiliation(s)
- Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, United States.
| | - Maria Teresa Carrì
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy; Fondazione Santa Lucia IRCCS, Via Ardeatina 306, Rome, Italy
| | - Philip M Beart
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3010, Australia
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25
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Bordt EA, Clerc P, Roelofs BA, Saladino AJ, Tretter L, Adam-Vizi V, Cherok E, Khalil A, Yadava N, Ge SX, Francis TC, Kennedy NW, Picton LK, Kumar T, Uppuluri S, Miller AM, Itoh K, Karbowski M, Sesaki H, Hill RB, Polster BM. The Putative Drp1 Inhibitor mdivi-1 Is a Reversible Mitochondrial Complex I Inhibitor that Modulates Reactive Oxygen Species. Dev Cell 2017; 40:583-594.e6. [PMID: 28350990 DOI: 10.1016/j.devcel.2017.02.020] [Citation(s) in RCA: 355] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 01/19/2017] [Accepted: 02/24/2017] [Indexed: 11/15/2022]
Abstract
Mitochondrial fission mediated by the GTPase dynamin-related protein 1 (Drp1) is an attractive drug target in numerous maladies that range from heart disease to neurodegenerative disorders. The compound mdivi-1 is widely reported to inhibit Drp1-dependent fission, elongate mitochondria, and mitigate brain injury. Here, we show that mdivi-1 reversibly inhibits mitochondrial complex I-dependent O2 consumption and reverse electron transfer-mediated reactive oxygen species (ROS) production at concentrations (e.g., 50 μM) used to target mitochondrial fission. Respiratory inhibition is rescued by bypassing complex I using yeast NADH dehydrogenase Ndi1. Unexpectedly, respiratory impairment by mdivi-1 occurs without mitochondrial elongation, is not mimicked by Drp1 deletion, and is observed in Drp1-deficient fibroblasts. In addition, mdivi-1 poorly inhibits recombinant Drp1 GTPase activity (Ki > 1.2 mM). Overall, these results suggest that mdivi-1 is not a specific Drp1 inhibitor. The ability of mdivi-1 to reversibly inhibit complex I and modify mitochondrial ROS production may contribute to effects observed in disease models.
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Affiliation(s)
- Evan A Bordt
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Pascaline Clerc
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian A Roelofs
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Andrew J Saladino
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Pathology and Laboratory Medicine Service, Department of Veterans Affairs Medical Center, Baltimore, MD 21201, USA
| | - László Tretter
- MTA-SE Laboratory for Neurobiochemistry, Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
| | - Vera Adam-Vizi
- MTA-SE Laboratory for Neurobiochemistry, Department of Medical Biochemistry, Semmelweis University, Budapest 1094, Hungary
| | - Edward Cherok
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ahmed Khalil
- Pioneer Valley Life Sciences Institute, Springfield, MA 01109, USA; Baystate Medical Center, Springfield, MA 01109, USA
| | - Nagendra Yadava
- Pioneer Valley Life Sciences Institute, Springfield, MA 01109, USA; Baystate Medical Center, Springfield, MA 01109, USA; Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Shealinna X Ge
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - T Chase Francis
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nolan W Kennedy
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Lora K Picton
- Department of Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Tanya Kumar
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Sruti Uppuluri
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Alexandrea M Miller
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kie Itoh
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Mariusz Karbowski
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - R Blake Hill
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian M Polster
- Department of Anesthesiology, The Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Jaber SM, Polster BM. An in vitro model yields 'importin' new insights into chronic traumatic encephalopathy: damaged astrocytes stop 'thrombospondin' to the injury: An Editorial Highlight for 'Defective synthesis and release of astrocytic thrombospondin-1 mediates the neuronal TDP-43 proteinopathy, resulting in defects in neuronal integrity associated with chronic traumatic encephalopathy: in vitro studies'. J Neurochem 2017; 140:531-535. [PMID: 28074610 DOI: 10.1111/jnc.13906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 11/11/2016] [Indexed: 01/08/2023]
Abstract
Read the highlighted article 'Defective synthesis and release of astrocytic thrombospondin-1 mediates the neuronal TDP-43 proteinopathy, resulting in defects in neuronal integrity associated with chronic traumatic encephalopathy: in vitro studies' on page 645.
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Affiliation(s)
- Sausan M Jaber
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Brian M Polster
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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27
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Choe M, Brusgard JL, Chumsri S, Bhandary L, Zhao XF, Lu S, Goloubeva OG, Polster BM, Fiskum GM, Girnun GD, Kim MS, Passaniti A. The RUNX2 Transcription Factor Negatively Regulates SIRT6 Expression to Alter Glucose Metabolism in Breast Cancer Cells. J Cell Biochem 2016; 116:2210-26. [PMID: 25808624 DOI: 10.1002/jcb.25171] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 03/20/2015] [Indexed: 12/21/2022]
Abstract
Activation of genes promoting aerobic glycolysis and suppression of mitochondrial oxidative phosphorylation is one of the hallmarks of cancer. The RUNX2 transcription factor mediates breast cancer (BC) metastasis to bone and is regulated by glucose availability. But, the mechanisms by which it regulates glucose metabolism and promotes an oncogenic phenotype are not known. RUNX2 expression in luminal BC cells correlated with lower estrogen receptor-α (ERα) levels, anchorage-independent growth, expression of glycolytic genes, increased glucose uptake, and sensitivity to glucose starvation, but not to inhibitors of oxidative phosphorylation. Conversely, RUNX2 knockdown in triple-negative BC cells inhibited mammosphere formation and glucose dependence. RUNX2 knockdown resulted in lower LDHA, HK2, and GLUT1 glycolytic gene expression, but upregulation of pyruvate dehydrogenase-A1 (PDHA1) mRNA and enzymatic activity, which was consistent with lower glycolytic potential. The NAD-dependent histone deacetylase, SIRT6, a known tumor suppressor, was a critical regulator of these RUNX2-mediated metabolic changes. RUNX2 expression resulted in elevated pAkt, HK2, and PDHK1 glycolytic protein levels that were reduced by ectopic expression of SIRT6. RUNX2 also repressed mitochondrial oxygen consumption rates (OCR), a measure of oxidative phosphorylation (respiration). Overexpression of SIRT6 increased respiration in RUNX2-positive cells, but knockdown of SIRT6 in cells expressing low RUNX2 decreased respiration. RUNX2 repressed SIRT6 expression at both the transcriptional and post-translational levels and endogenous SIRT6 expression was lower in malignant BC tissues or cell lines that expressed high levels of RUNX2. These results support a hypothesis whereby RUNX2-mediated repression of the SIRT6 tumor suppressor regulates metabolic pathways that promote BC progression.
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Affiliation(s)
- Moran Choe
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland.,Laboratory of Genitourinary Cancer Pathogenesis, NCI, Building 36/Room 1130, 37 Convent Drive, Bethesda, Maryland, 20814
| | - Jessica L Brusgard
- Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Saranya Chumsri
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Lekhana Bhandary
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Xianfeng Frank Zhao
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland.,Department of Pathology and the VA San Diego Healthcare System, University of California, San Diego, California, 92161
| | - Song Lu
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Olga G Goloubeva
- Department of Epidemiology & Public Health, The Marlene & Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Brian M Polster
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gary M Fiskum
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Geoffrey D Girnun
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland.,Department of Pathology, Stony Brook University Medical Center, Stony Brook, New York, 11794
| | - Myoung Sook Kim
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Antonino Passaniti
- Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland.,Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, Maryland.,Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland.,The Veteran's Health Administration Research & Development Service, Marlene & Stewart Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland
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Kim MS, Choe M, Cho H, Polster BM, Girnun GD, Passaniti A. Abstract P5-05-02: Regulation of glucose metabolism by the RUNX2 transcription factor has a negative impact on mitochondrial function in breast cancer cells. Cancer Res 2016. [DOI: 10.1158/1538-7445.sabcs15-p5-05-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The RUNX2 transcription factor regulates breast cancer (BC) metastasis to bone and is itself a target of IGF-1 signaling pathways. We have shown that glucose can activate RUNX2 phopshorylation through IGF-1 receptor signaling and that RUNX2 was associated with inhibition of pyruvate dehydrogenase (PDHA1) activity and repression of mitochondrial respiration in BC cells. However, the mechanisms by which RUNX2 alters mitochondrial function and supports an oncogenic phenotype are not completely known. RUNX2 expression in a luminal BC cell line increased expression of glycolytic genes, and sensitivity to glucose starvation. However, RUNX2 knockdown in a triple-negative BC cell line inhibited expression of glycolytic genes. RUNX2 also repressed mitochondrial oxygen consumption rates (OCR), a measure of oxidative phosphorylation while overexpression of SIRT6, a NAD-dependent histone deacetylase, increased respiration in RUNX2-positive cells. RUNX2 repressed SIRT6 expression directly at the transcriptional and post-translational levels. High SIRT6 expression was observed in normal mammary tissue and cells that did not express RUNX2 but endogenous SIRT6 expression was low in malignant BC tissues or cell lines, which expressed high levels of RUNX2. These results suggest that SIRT6, a known tumor suppressor, was a critical mediator of these RUNX2-regulated metabolic changes. These results support a hypothesis whereby RUNX2 upregulation during BC progression leads to inactivation of the SIRT6 tumor suppressor to promote tumorigenesis. It will be important to investigate further changes in mitochondrial function to understand the precise mechanisms by which RUNX2 regulates BC metabolism.
Citation Format: Kim MS, Choe M, Cho H, Polster BM, Girnun GD, Passaniti A. Regulation of glucose metabolism by the RUNX2 transcription factor has a negative impact on mitochondrial function in breast cancer cells. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-05-02.
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Affiliation(s)
- MS Kim
- University of Maryland, Baltimore, Baltimore, MD; Stony Brook University, Stony Brook, NY
| | - M Choe
- University of Maryland, Baltimore, Baltimore, MD; Stony Brook University, Stony Brook, NY
| | - H Cho
- University of Maryland, Baltimore, Baltimore, MD; Stony Brook University, Stony Brook, NY
| | - BM Polster
- University of Maryland, Baltimore, Baltimore, MD; Stony Brook University, Stony Brook, NY
| | - GD Girnun
- University of Maryland, Baltimore, Baltimore, MD; Stony Brook University, Stony Brook, NY
| | - A Passaniti
- University of Maryland, Baltimore, Baltimore, MD; Stony Brook University, Stony Brook, NY
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29
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Xu S, Cherok E, Das S, Li S, Roelofs BA, Ge SX, Polster BM, Boyman L, Lederer WJ, Wang C, Karbowski M. Mitochondrial E3 ubiquitin ligase MARCH5 controls mitochondrial fission and cell sensitivity to stress-induced apoptosis through regulation of MiD49 protein. Mol Biol Cell 2015; 27:349-59. [PMID: 26564796 PMCID: PMC4713136 DOI: 10.1091/mbc.e15-09-0678] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/04/2015] [Indexed: 12/27/2022] Open
Abstract
The data presented support a critical role for MARCH5 in the regulation of mitochondrial fission and cell viability. Through ubiquitin- and proteasome-dependent degradation of MiD49, MARCH5 acts as a negative regulator of mitochondrial fission and thereby initiates a mechanism that affords the cell protection from stress-induced apoptosis. Ubiquitin- and proteasome-dependent outer mitochondrial membrane (OMM)-associated degradation (OMMAD) is critical for mitochondrial and cellular homeostasis. However, the scope and molecular mechanisms of the OMMAD pathways are still not well understood. We report that the OMM-associated E3 ubiquitin ligase MARCH5 controls dynamin-related protein 1 (Drp1)-dependent mitochondrial fission and cell sensitivity to stress-induced apoptosis. MARCH5 knockout selectively inhibited ubiquitination and proteasomal degradation of MiD49, a mitochondrial receptor of Drp1, and consequently led to mitochondrial fragmentation. Mitochondrial fragmentation in MARCH5−/− cells was not associated with inhibition of mitochondrial fusion or bioenergetic defects, supporting the possibility that MARCH5 is a negative regulator of mitochondrial fission. Both MARCH5 re-expression and MiD49 knockout in MARCH5−/− cells reversed mitochondrial fragmentation and reduced sensitivity to stress-induced apoptosis. These findings and data showing MARCH5-dependent degradation of MiD49 upon stress support the possibility that MARCH5 regulation of MiD49 is a novel mechanism controlling mitochondrial fission and, consequently, the cellular response to stress.
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Affiliation(s)
- Shan Xu
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Edward Cherok
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Shweta Das
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Sunan Li
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Brian A Roelofs
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Shealinna X Ge
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Brian M Polster
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Chunxin Wang
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Mariusz Karbowski
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201 Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201
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Nichols M, Zhang J, Polster BM, Elustondo PA, Thirumaran A, Pavlov EV, Robertson GS. Synergistic neuroprotection by epicatechin and quercetin: Activation of convergent mitochondrial signaling pathways. Neuroscience 2015; 308:75-94. [PMID: 26363153 DOI: 10.1016/j.neuroscience.2015.09.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 08/25/2015] [Accepted: 09/03/2015] [Indexed: 01/08/2023]
Abstract
In view of evidence that increased consumption of epicatechin (E) and quercetin (Q) may reduce the risk of stroke, we have measured the effects of combining E and Q on mitochondrial function and neuronal survival following oxygen-glucose deprivation (OGD). Relative to mouse cortical neuron cultures pretreated (24h) with either E or Q (0.1-10μM), E+Q synergistically attenuated OGD-induced neuronal cell death. E, Q and E+Q (0.3μM) increased spare respiratory capacity but only E+Q (0.3μM) preserved this crucial parameter of neuronal mitochondrial function after OGD. These improvements were accompanied by corresponding increases in cyclic AMP response element binding protein (CREB) phosphorylation and the expression of CREB-target genes that promote neuronal survival (Bcl-2) and mitochondrial biogenesis (PGC-1α). Consistent with these findings, E+Q (0.1 and 1.0μM) elevated mitochondrial gene expression (MT-ND2 and MT-ATP6) to a greater extent than E or Q after OGD. Q (0.3-3.0μM), but not E (3.0μM), elevated cytosolic calcium (Ca(2+)) spikes and the mitochondrial membrane potential. Conversely, E and E+Q (0.1 and 0.3μM), but not Q (0.1 and 0.3μM), activated protein kinase B (Akt). Nitric oxide synthase (NOS) inhibition with L-N(G)-nitroarginine methyl ester (1.0μM) blocked neuroprotection by E (0.3μM) or Q (1.0μM). Oral administration of E+Q (75mg/kg; once daily for 5days) reduced hypoxic-ischemic brain injury. These findings suggest E and Q activate Akt- and Ca(2+)-mediated signaling pathways that converge on NOS and CREB resulting in synergistic improvements in neuronal mitochondrial performance which confer profound protection against ischemic injury.
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Affiliation(s)
- M Nichols
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Brain Repair Centre, Faculty of Medicine, Dalhousie University, Life Sciences Research Institute, 1348 Summer Street, P.O. Box 15000, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - J Zhang
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Brain Repair Centre, Faculty of Medicine, Dalhousie University, Life Sciences Research Institute, 1348 Summer Street, P.O. Box 15000, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - B M Polster
- Department of Anesthesiology, Center for Shock Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - P A Elustondo
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - A Thirumaran
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Brain Repair Centre, Faculty of Medicine, Dalhousie University, Life Sciences Research Institute, 1348 Summer Street, P.O. Box 15000, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - E V Pavlov
- Department of Basic Sciences, College of Dentistry, New York University, 345 East 24th Street, New York, NY 10010, USA.
| | - G S Robertson
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Psychiatry, 5909 Veterans' Memorial Lane, 8th Floor Abbie J. Lane Memorial Building, QEII Health Sciences Centre, Halifax, Nova Scotia B3H 2E2, Canada.
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Roelofs BA, Ge SX, Studlack PE, Polster BM. Low micromolar concentrations of the superoxide probe MitoSOX uncouple neural mitochondria and inhibit complex IV. Free Radic Biol Med 2015; 86:250-8. [PMID: 26057935 PMCID: PMC4554824 DOI: 10.1016/j.freeradbiomed.2015.05.032] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 12/12/2022]
Abstract
MitoSOX Red is a fluorescent probe used for the detection of mitochondrial reactive oxygen species by live cell imaging. The lipophilic, positively charged triphenylphosphonium moiety within MitoSOX concentrates the superoxide-sensitive dihydroethidium conjugate within the mitochondrial matrix. Here we investigated whether common MitoSOX imaging protocols influence mitochondrial bioenergetic function in primary rat cortical neurons and microglial cell lines. MitoSOX dose-dependently uncoupled neuronal respiration, whether present continuously in the assay medium or washed following a ten minute loading protocol. Concentrations of 5-10μM MitoSOX caused severe loss of ATP synthesis-linked respiration. Redistribution of MitoSOX to the cytoplasm and nucleus occurred concomitant to mitochondrial uncoupling. MitoSOX also dose-dependently decreased the maximal respiration rate and this impairment could not be rescued by delivery of a complex IV specific substrate, revealing complex IV inhibition. As in neurons, loading microglial cells with MitoSOX at low micromolar concentrations resulted in uncoupled mitochondria with reduced respiratory capacity whereas submicromolar MitoSOX had no adverse effects. The MitoSOX parent compound dihydroethidium also caused mitochondrial uncoupling and respiratory inhibition at low micromolar concentrations. However, these effects were abrogated by pre-incubating dihydroethidium with cation exchange beads to remove positively charged oxidation products, which would otherwise by sequestered by polarized mitochondria. Collectively, our results suggest that the matrix accumulation of MitoSOX or dihydroethidium oxidation products causes mitochondrial uncoupling and inhibition of complex IV. Because MitoSOX is inherently capable of causing severe mitochondrial dysfunction with the potential to alter superoxide production, its use therefore requires careful optimization in imaging protocols.
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Affiliation(s)
- Brian A Roelofs
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR); Department of Biochemistry and Molecular Biology
| | - Shealinna X Ge
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR)
| | - Paige E Studlack
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, U.S.A
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR); Department of Biochemistry and Molecular Biology; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, U.S.A.
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Bol GM, Vesuna F, Xie M, Zeng J, Aziz K, Gandhi N, Levine A, Irving A, Korz D, Tantravedi S, Heerma van Voss MR, Gabrielson K, Bordt EA, Polster BM, Cope L, van der Groep P, Kondaskar A, Rudek MA, Hosmane RS, van der Wall E, van Diest PJ, Tran PT, Raman V. Targeting DDX3 with a small molecule inhibitor for lung cancer therapy. EMBO Mol Med 2015; 7:648-69. [PMID: 25820276 PMCID: PMC4492822 DOI: 10.15252/emmm.201404368] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 02/09/2015] [Accepted: 02/12/2015] [Indexed: 12/15/2022] Open
Abstract
Lung cancer is the most common malignancy worldwide and is a focus for developing targeted therapies due to its refractory nature to current treatment. We identified a RNA helicase, DDX3, which is overexpressed in many cancer types including lung cancer and is associated with lower survival in lung cancer patients. We designed a first-in-class small molecule inhibitor, RK-33, which binds to DDX3 and abrogates its activity. Inhibition of DDX3 by RK-33 caused G1 cell cycle arrest, induced apoptosis, and promoted radiation sensitization in DDX3-overexpressing cells. Importantly, RK-33 in combination with radiation induced tumor regression in multiple mouse models of lung cancer. Mechanistically, loss of DDX3 function either by shRNA or by RK-33 impaired Wnt signaling through disruption of the DDX3-β-catenin axis and inhibited non-homologous end joining-the major DNA repair pathway in mammalian somatic cells. Overall, inhibition of DDX3 by RK-33 promotes tumor regression, thus providing a compelling argument to develop DDX3 inhibitors for lung cancer therapy.
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Affiliation(s)
- Guus M Bol
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Farhad Vesuna
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Min Xie
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jing Zeng
- Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Khaled Aziz
- Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nishant Gandhi
- Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anne Levine
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ashley Irving
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dorian Korz
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Saritha Tantravedi
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marise R Heerma van Voss
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Kathleen Gabrielson
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Evan A Bordt
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Brian M Polster
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Leslie Cope
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Petra van der Groep
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Atul Kondaskar
- Department of Chemistry & Biochemistry, University of Maryland, Baltimore County, MD, USA
| | - Michelle A Rudek
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ramachandra S Hosmane
- Department of Chemistry & Biochemistry, University of Maryland, Baltimore County, MD, USA
| | - Elsken van der Wall
- Department of Internal Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paul J van Diest
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Phuoc T Tran
- Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Venu Raman
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Clerc P, Ge SX, Hwang H, Waddell J, Roelofs BA, Karbowski M, Sesaki H, Polster BM. Drp1 is dispensable for apoptotic cytochrome c release in primed MCF10A and fibroblast cells but affects Bcl-2 antagonist-induced respiratory changes. Br J Pharmacol 2014; 171:1988-99. [PMID: 24206264 DOI: 10.1111/bph.12515] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 10/25/2013] [Accepted: 10/30/2013] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Dynamin-related protein 1 (Drp1) mediates mitochondrial fission and is thought to promote Bax/Bak-induced cytochrome c release during apoptosis. Conformationally active Bax, Bak and Bax/Bak-activating BH3-only proteins, such as Bim, are restrained by anti-apoptotic Bcl-2 proteins in cells that are 'primed for death'. Inhibition of Bcl-2/Bcl-xL/Bcl-w by the antagonist ABT-737 causes rapid apoptosis of primed cells. Hence, we determined whether Drp1 is required for cytochrome c release, respiratory alterations and apoptosis of cells that are already primed for death. EXPERIMENTAL APPROACH We tested the Drp1 inhibitor mdivi-1 for inhibition of cytochrome c release in MCF10A cells primed by Bcl-2 overexpression. We measured ATP synthesis-dependent, -independent and cytochrome c-limited maximal oxygen consumption rates (OCRs) and cell death of immortalized wild-type (WT) and Drp1 knockout (KO) mouse embryonic fibroblasts (MEFs) treated with ABT-737. KEY RESULTS Mdivi-1 failed to attenuate ABT-737-induced cytochrome c release. ABT-737 decreased maximal OCR measured in the presence of uncoupler in both WT and Drp1 KO MEF, consistent with respiratory impairment due to release of cytochrome c. However, Drp1 KO MEF were slightly less sensitive to this ABT-737-induced respiratory inhibition compared with WT, and were resistant to an initial ABT-737-induced increase in ATP synthesis-independent O2 consumption. Nevertheless, caspase-dependent cell death was not reduced. Pro-apoptotic Bax was unaltered, whereas Bak was up-regulated in Drp1 KO MEF. CONCLUSIONS AND IMPLICATIONS The findings indicate that once fibroblast cells are primed for death, Drp1 is not required for apoptosis. However, Drp1 may contribute to ABT-737-induced respiratory changes and the kinetics of cytochrome c release.
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Affiliation(s)
- P Clerc
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, USA
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Bordt EA, Polster BM. NADPH oxidase- and mitochondria-derived reactive oxygen species in proinflammatory microglial activation: a bipartisan affair? Free Radic Biol Med 2014; 76:34-46. [PMID: 25091898 PMCID: PMC4252610 DOI: 10.1016/j.freeradbiomed.2014.07.033] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/19/2014] [Accepted: 07/24/2014] [Indexed: 12/18/2022]
Abstract
Microglia are the resident immune cells of the brain and play major roles in central nervous system development, maintenance, and disease. Brain insults cause microglia to proliferate, migrate, and transform into one or more activated states. Classical M1 activation triggers the production of proinflammatory factors such as tumor necrosis factor-α, interleukin-1β (IL-1β), nitric oxide, and reactive oxygen species (ROS), which, in excess, can exacerbate brain injury. The mechanisms underlying microglial activation are not fully understood, yet reactive oxygen species are increasingly implicated as mediators of microglial activation. In this review, we highlight studies linking reactive oxygen species, in particular hydrogen peroxide derived from NADPH oxidase-generated superoxide, to the classical activation of microglia. In addition, we critically evaluate controversial evidence suggesting a specific role for mitochondrial reactive oxygen species in the activation of the NLRP3 inflammasome, a multiprotein complex that mediates the production of IL-1β and IL-18. Finally, the limitations of common techniques used to implicate mitochondrial ROS in microglial and inflammasome activation, such as the use of the mitochondrially targeted ROS indicator MitoSOX and the mitochondrially targeted antioxidant MitoTEMPO, are also discussed.
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Affiliation(s)
- Evan A Bordt
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research, and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian M Polster
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research, and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Jaber S, Polster BM. Idebenone and neuroprotection: antioxidant, pro-oxidant, or electron carrier? J Bioenerg Biomembr 2014; 47:111-8. [PMID: 25262284 DOI: 10.1007/s10863-014-9571-y] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/15/2014] [Indexed: 12/30/2022]
Abstract
UNLABELLED Ubiquinone, commonly called coenzyme Q10 (CoQ), is a lipophilic electron carrier and endogenous antioxidant found in all cellular membranes. In the mitochondrial inner membrane it transfers electrons to complex III of the electron transport chain. The short chain CoQ analogue idebenone is in clinical trials for a number of diseases that exhibit a mitochondrial etiology. Nevertheless, evidence that idebenone ameliorates neurological symptoms in human disease is inconsistent. Although championed as an antioxidant, idebenone can also act as a pro-oxidant by forming an unstable semiquinone at complex I. The antioxidant function of idebenone is critically dependent on two-electron reduction to idebenol without the creation of unstable intermediates. Recently, cytoplasmic NAD(P)H quinone oxidoreductase 1 (NQO1) was identified as a major enzyme catalyzing idebenone reduction. While reduction allows idebenone to act as an antioxidant, evidence also suggests that NQO1 enables idebenone to shuttle reducing equivalents from cytoplasmic NAD(P)H to mitochondrial complex III, bypassing any upstream damage to the electron transport chain. In this mini-review we discuss how idebenone can influence mitochondrial function within the context of cytoprotection. Importantly, in the brain NQO1 is expressed primarily by glia rather than neurons. As NQO1 is an inducible enzyme regulated by oxidative stress and the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway, optimizing NQO1 expression in appropriate cell types within a specific disease context may be key to delivering on idebenone's therapeutic potential.
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Affiliation(s)
- Sausan Jaber
- Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore St., MSTF 5-34, Baltimore, MD, 21201, USA
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Clerc P, Young CA, Bordt EA, Grigore AM, Fiskum G, Polster BM. Magnesium sulfate protects against the bioenergetic consequences of chronic glutamate receptor stimulation. PLoS One 2013; 8:e79982. [PMID: 24236167 PMCID: PMC3827425 DOI: 10.1371/journal.pone.0079982] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 09/28/2013] [Indexed: 11/26/2022] Open
Abstract
Extracellular glutamate is elevated following brain ischemia or trauma and contributes to neuronal injury. We tested the hypothesis that magnesium sulfate (MgSO4, 3 mM) protects against metabolic failure caused by excitotoxic glutamate exposure. Rat cortical neuron preparations treated in medium already containing a physiological concentration of Mg2+ (1 mM) could be segregated based on their response to glutamate (100 µM). Type I preparations responded with a decrease or small transient increase in oxygen consumption rate (OCR). Type II neurons responded with >50% stimulation in OCR, indicating a robust response to increased energy demand without immediate toxicity. Pre-treatment with MgSO4 improved the initial bioenergetic response to glutamate and ameliorated subsequent loss of spare respiratory capacity, measured following addition of the uncoupler FCCP, in Type I but not Type II neurons. Spare respiratory capacity in Type I neurons was also improved by incubation with MgSO4 or NMDA receptor antagonist MK801 in the absence of glutamate treatment. This finding indicates that the major difference between Type I and Type II preparations is the amount of endogenous glutamate receptor activity. Incubation of Type II neurons with 5 µM glutamate prior to excitotoxic (100 µM) glutamate exposure recapitulated a Type I phenotype. MgSO4 protected against an excitotoxic glutamate-induced drop in neuronal ATP both with and without prior 5 µM glutamate exposure. Results indicate that MgSO4 protects against chronic moderate glutamate receptor stimulation and preserves cellular ATP following treatment with excitotoxic glutamate.
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Affiliation(s)
- Pascaline Clerc
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Christina A. Young
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Evan A. Bordt
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alina M. Grigore
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Gary Fiskum
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Brian M. Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Polster BM. AIF, reactive oxygen species, and neurodegeneration: a "complex" problem. Neurochem Int 2012; 62:695-702. [PMID: 23246553 DOI: 10.1016/j.neuint.2012.12.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/26/2012] [Accepted: 12/05/2012] [Indexed: 12/21/2022]
Abstract
Apoptosis-inducing factor (AIF) is a flavin-binding mitochondrial intermembrane space protein that is implicated in diverse but intertwined processes that include maintenance of electron transport chain function, reactive oxygen species regulation, cell death, and neurodegeneration. In acute brain injury, AIF acquires a pro-death role upon translocation from the mitochondria to the nucleus, where it initiates chromatin condensation and large-scale DNA fragmentation. Although harlequin mice exhibiting an 80-90% global reduction in AIF protein are resistant to numerous forms of acute brain injury, they paradoxically undergo slow, progressive neurodegeneration beginning at three months of age. Brain deterioration, accompanied by markers of oxidative stress, is most pronounced in the cerebellum and retina, although it also occurs in the cortex, striatum, and thalamus. Loss of an AIF pro-survival function linked to assembly or stabilization of electron transport chain complex I underlies chronic neurodegeneration. To date, most studies of neurodegeneration have failed to adequately separate the relative importance of the mitochondrial and nuclear functions of AIF in determining the extent of injury, or whether oxidative stress plays a causative role. This review explores the complicated relationship among AIF, complex I, and the regulation of mitochondrial reactive oxygen species levels. It also discusses the controversial role of complex I deficiency in Parkinson's disease, and what can be learned from the AIF- and complex I-depleted harlequin mouse.
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Affiliation(s)
- Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore St., MSTF 5-34, Baltimore, MD 21201, USA.
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Clerc P, Carey GB, Mehrabian Z, Wei M, Hwang H, Girnun GD, Chen H, Martin SS, Polster BM. Rapid detection of an ABT-737-sensitive primed for death state in cells using microplate-based respirometry. PLoS One 2012; 7:e42487. [PMID: 22880001 PMCID: PMC3411749 DOI: 10.1371/journal.pone.0042487] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 07/09/2012] [Indexed: 12/31/2022] Open
Abstract
Cells that exhibit an absolute dependence on the anti-apoptotic BCL-2 protein for survival are termed “primed for death” and are killed by the BCL-2 antagonist ABT-737. Many cancers exhibit a primed phenotype, including some that are resistant to conventional chemotherapy due to high BCL-2 expression. We show here that 1) stable BCL-2 overexpression alone can induce a primed for death state and 2) that an ABT-737-induced loss of functional cytochrome c from the electron transport chain causes a reduction in maximal respiration that is readily detectable by microplate-based respirometry. Stable BCL-2 overexpression sensitized non-tumorigenic MCF10A mammary epithelial cells to ABT-737-induced caspase-dependent apoptosis. Mitochondria within permeabilized BCL-2 overexpressing cells were selectively vulnerable to ABT-737-induced cytochrome c release compared to those from control-transfected cells, consistent with a primed state. ABT-737 treatment caused a dose-dependent impairment of maximal O2 consumption in MCF10A BCL-2 overexpressing cells but not in control-transfected cells or in immortalized mouse embryonic fibroblasts lacking both BAX and BAK. This impairment was rescued by delivering exogenous cytochrome c to mitochondria via saponin-mediated plasma membrane permeabilization. An ABT-737-induced reduction in maximal O2 consumption was also detectable in SP53, JeKo-1, and WEHI-231 B-cell lymphoma cell lines, with sensitivity correlating with BCL-2:MCL-1 ratio and with susceptibility (SP53 and JeKo-1) or resistance (WEHI-231) to ABT-737-induced apoptosis. Multiplexing respirometry assays to ELISA-based determination of cytochrome c redistribution confirmed that respiratory inhibition was associated with cytochrome c release. In summary, cell-based respiration assays were able to rapidly identify a primed for death state in cells with either artificially overexpressed or high endogenous BCL-2. Rapid detection of a primed for death state in individual cancers by “bioenergetics-based profiling” may eventually help identify the subset of patients with chemoresistant but primed tumors who can benefit from treatment that incorporates a BCL-2 antagonist.
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Affiliation(s)
- Pascaline Clerc
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Gregory B. Carey
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Zara Mehrabian
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Michael Wei
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Hyehyun Hwang
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Geoffrey D. Girnun
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Hegang Chen
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Stuart S. Martin
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Brian M. Polster
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Clerc P, Polster BM. Investigation of mitochondrial dysfunction by sequential microplate-based respiration measurements from intact and permeabilized neurons. PLoS One 2012; 7:e34465. [PMID: 22496810 PMCID: PMC3319583 DOI: 10.1371/journal.pone.0034465] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 03/02/2012] [Indexed: 11/27/2022] Open
Abstract
Mitochondrial dysfunction is a component of many neurodegenerative conditions. Measurement of oxygen consumption from intact neurons enables evaluation of mitochondrial bioenergetics under conditions that are more physiologically realistic compared to isolated mitochondria. However, mechanistic analysis of mitochondrial function in cells is complicated by changing energy demands and lack of substrate control. Here we describe a technique for sequentially measuring respiration from intact and saponin-permeabilized cortical neurons on single microplates. This technique allows control of substrates to individual electron transport chain complexes following permeabilization, as well as side-by-side comparisons to intact cells. To illustrate the utility of the technique, we demonstrate that inhibition of respiration by the drug KB-R7943 in intact neurons is relieved by delivery of the complex II substrate succinate, but not by complex I substrates, via acute saponin permeabilization. In contrast, methyl succinate, a putative cell permeable complex II substrate, failed to rescue respiration in intact neurons and was a poor complex II substrate in permeabilized cells. Sequential measurements of intact and permeabilized cell respiration should be particularly useful for evaluating indirect mitochondrial toxicity due to drugs or cellular signaling events which cannot be readily studied using isolated mitochondria.
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Affiliation(s)
| | - Brian M. Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Khairallah RJ, Kim J, O'Shea KM, O'Connell KA, Brown BH, Galvao T, Daneault C, Rosiers CD, Polster BM, Hoppel CL, Stanley WC. Improved mitochondrial function with diet-induced increase in either docosahexaenoic acid or arachidonic acid in membrane phospholipids. PLoS One 2012; 7:e34402. [PMID: 22479624 PMCID: PMC3316678 DOI: 10.1371/journal.pone.0034402] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/27/2012] [Indexed: 01/11/2023] Open
Abstract
Mitochondria can depolarize and trigger cell death through the opening of the mitochondrial permeability transition pore (MPTP). We recently showed that an increase in the long chain n3 polyunsaturated fatty acids (PUFA) docosahexaenoic acid (DHA; 22:6n3) and depletion of the n6 PUFA arachidonic acid (ARA; 20:4n6) in mitochondrial membranes is associated with a greater Ca2+ load required to induce MPTP opening. Here we manipulated mitochondrial phospholipid composition by supplementing the diet with DHA, ARA or combined DHA+ARA in rats for 10 weeks. There were no effects on cardiac function, or respiration of isolated mitochondria. Analysis of mitochondrial phospholipids showed DHA supplementation increased DHA and displaced ARA in mitochondrial membranes, while supplementation with ARA or DHA+ARA increased ARA and depleted linoleic acid (18:2n6). Phospholipid analysis revealed a similar pattern, particularly in cardiolipin. Tetralinoleoyl cardiolipin was depleted by 80% with ARA or DHA+ARA supplementation, with linoleic acid side chains replaced by ARA. Both the DHA and ARA groups had delayed Ca2+-induced MPTP opening, but the DHA+ARA group was similar to the control diet. In conclusion, alterations in mitochondria membrane phospholipid fatty acid composition caused by dietary DHA or ARA was associated with a greater cumulative Ca2+ load required to induced MPTP opening. Further, high levels of tetralinoleoyl cardiolipin were not essential for normal mitochondrial function if replaced with very-long chain n3 or n6 PUFAs.
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Affiliation(s)
- Ramzi J. Khairallah
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Junhwan Kim
- Department of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Karen M. O'Shea
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Kelly A. O'Connell
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Bethany H. Brown
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Tatiana Galvao
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Caroline Daneault
- Department of Nutrition and Montreal Heart Institute, Université de Montréal, Montreal, Quebecc, Canada
| | - Christine Des Rosiers
- Department of Nutrition and Montreal Heart Institute, Université de Montréal, Montreal, Quebecc, Canada
| | - Brian M. Polster
- Department of Anesthesiology, and Shock, Trauma, and the Anesthesiology Research (STAR) Center, University of Maryland, Baltimore, Maryland, United States of America
| | - Charles L. Hoppel
- Department of Medicine and Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - William C. Stanley
- Division of Cardiology, Department of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- * E-mail:
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McCranor BJ, Bozym RA, Vitolo MI, Fierke CA, Bambrick L, Polster BM, Fiskum G, Thompson RB. Quantitative imaging of mitochondrial and cytosolic free zinc levels in an in vitro model of ischemia/reperfusion. J Bioenerg Biomembr 2012; 44:253-63. [PMID: 22430627 DOI: 10.1007/s10863-012-9427-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 12/17/2011] [Indexed: 01/25/2023]
Abstract
The role of zinc ion in cytotoxicity following ischemic stroke, prolonged status epilepticus, and traumatic brain injury remains controversial, but likely is the result of mitochondrial dysfunction. We describe an excitation ratiometric fluorescence biosensor based on human carbonic anhydrase II variants expressed in the mitochondrial matrix, permitting free zinc levels to be quantitatively imaged therein. We observed an average mitochondrial matrix free zinc concentration of 0.2 pM in the PC12 rat pheochromacytoma cell culture line. Cytoplasmic and mitochondrial free zinc levels were imaged in a cellular oxygen glucose deprivation (OGD) model of ischemia/reperfusion. We observed a significant increase in mitochondrial zinc 1 h following 3 h OGD, at a time point when cytosolic zinc levels were depressed. Following the increase, mitochondrial zinc levels returned to physiological levels, while cytosolic zinc increased gradually over a 24 h time period in viable cells. The increase in intramitochondrial zinc observed during reoxygenation after OGD may contribute to bioenergetic dysfunction and cell death that occurs with both in vitro and in vivo models of reperfusion.
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Affiliation(s)
- Bryan J McCranor
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St., Baltimore, MD 21201, USA
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Wang H, Sreenivasan U, Hu H, Saladino A, Polster BM, Lund LM, Gong DW, Stanley WC, Sztalryd C. Perilipin 5, a lipid droplet-associated protein, provides physical and metabolic linkage to mitochondria. J Lipid Res 2011; 52:2159-2168. [PMID: 21885430 DOI: 10.1194/jlr.m017939] [Citation(s) in RCA: 321] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Maintaining cellular lipid homeostasis is crucial to oxidative tissues, and it becomes compromised in obesity. Lipid droplets (LD) play a central role in lipid homeostasis by mediating fatty acid (FA) storage in the form of triglyceride, thereby lowering intracellular levels of lipids that mediate cellular lipotoxicity. LDs and mitochondria have interconnected functions, and anecdotal evidence suggests they physically interact. However, the mechanisms of interaction have not been identified. Perilipins are LD-scaffolding proteins and potential candidates to play a role in their interaction with mitochondria. We examined the contribution of LD perilipin composition to the physical and metabolic interactions between LD and mitochondria using multiple techniques: confocal imaging, electron microscopy (EM), and lipid storage and utilization measurements. Using neonatal cardiomyocytes, reconstituted cell culture models, and rodent heart tissues, we found that perilipin 5 (Plin5) recruits mitochondria to the LD surface through a C-terminal region. Compared with control cells, Plin5-expressing cells show decreased LD hydrolysis, decreased palmitate β-oxidation, and increased palmitate incorporation into triglycerides in basal conditions, whereas in stimulated conditions, LD hydrolysis inhibition is lifted and FA released for β-oxidation. These results suggest that Plin5 regulates oxidative LD hydrolysis and controls local FA flux to protect mitochondria against excessive exposure to FA during physiological stress.
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Affiliation(s)
- Hong Wang
- The Geriatric Research, Education and Clinical Center, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Urmilla Sreenivasan
- The Geriatric Research, Education and Clinical Center, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201; Baltimore Veterans Affairs Health Care Center, Division of Endocrinology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Hong Hu
- The Geriatric Research, Education and Clinical Center, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Andrew Saladino
- VAMHCS Blood/Tissue Banks and Hematology, Division of Pathology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Brian M Polster
- Department of Anesthesiology and the Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Linda M Lund
- Department of Medicine, Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Da-Wei Gong
- The Geriatric Research, Education and Clinical Center, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201; Baltimore Veterans Affairs Health Care Center, Division of Endocrinology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - William C Stanley
- Department of Medicine, Department of Physiology, School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Carole Sztalryd
- The Geriatric Research, Education and Clinical Center, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201; Baltimore Veterans Affairs Health Care Center, Division of Endocrinology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201.
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Zhang Z, Wakabayashi N, Wakabayashi J, Tamura Y, Song WJ, Sereda S, Clerc P, Polster BM, Aja SM, Pletnikov MV, Kensler TW, Shirihai OS, Iijima M, Hussain MA, Sesaki H. The dynamin-related GTPase Opa1 is required for glucose-stimulated ATP production in pancreatic beta cells. Mol Biol Cell 2011; 22:2235-45. [PMID: 21551073 PMCID: PMC3128526 DOI: 10.1091/mbc.e10-12-0933] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The physiological function of Opa1, a dynamin-related GTPase required for mitochondrial fusion, is described in glucose-stimulated ATP production in pancreatic beta cells. Previous studies using in vitro cell culture systems have shown the role of the dynamin-related GTPase Opa1 in apoptosis prevention and mitochondrial DNA (mtDNA) maintenance. However, it remains to be tested whether these functions of Opa1 are physiologically important in vivo in mammals. Here, using the Cre-loxP system, we deleted mouse Opa1 in pancreatic beta cells, in which glucose-stimulated ATP production in mitochondria plays a key role in insulin secretion. Beta cells lacking Opa1 maintained normal copy numbers of mtDNA; however, the amount and activity of electron transport chain complex IV were significantly decreased, leading to impaired glucose-stimulated ATP production and insulin secretion. In addition, in Opa1-null beta cells, cell proliferation was impaired, whereas apoptosis was not promoted. Consequently, mice lacking Opa1 in beta cells develop hyperglycemia. The data suggest that the function of Opa1 in the maintenance of the electron transport chain is physiologically relevant in beta cells.
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Affiliation(s)
- Zhongyan Zhang
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Schuh RA, Clerc P, Hwang H, Mehrabian Z, Bittman K, Chen H, Polster BM. Adaptation of microplate-based respirometry for hippocampal slices and analysis of respiratory capacity. J Neurosci Res 2011; 89:1979-88. [PMID: 21520220 DOI: 10.1002/jnr.22650] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/01/2011] [Accepted: 03/01/2011] [Indexed: 01/09/2023]
Abstract
Multiple neurodegenerative disorders are associated with altered mitochondrial bioenergetics. Although mitochondrial O(2) consumption is frequently measured in isolated mitochondria, isolated synaptic nerve terminals (synaptosomes), or cultured cells, the absence of mature brain circuitry is a remaining limitation. Here we describe the development of a method that adapts the Seahorse Extracellular Flux Analyzer (XF24) for the microplate-based measurement of hippocampal slice O(2) consumption. As a first evaluation of the technique, we compared whole-slice bioenergetics with previous measurements made with synaptosomes or cultured neurons. We found that mitochondrial respiratory capacity and O(2) consumption coupled to ATP synthesis could be estimated in cultured or acute hippocampal slices with preserved neural architecture. Mouse organotypic hippocampal slices oxidizing glucose displayed mitochondrial O(2) consumption that was well coupled, as determined by the sensitivity to the ATP synthase inhibitor oligomycin. However, stimulation of respiration by uncoupler was modest (<120% of basal respiration) compared with previous measurements in cells or synaptosomes, though enhanced slightly (to ∼150% of basal respiration) by acute addition of the mitochondrial complex I-linked substrate pyruvate. These findings suggest a high basal utilization of respiratory capacity in slices and a limitation of glucose-derived substrate for maximal respiration. The improved throughput of microplate-based hippocampal respirometry over traditional O(2) electrode-based methods is conducive to neuroprotective drug screening. When coupled with cell type-specific pharmacology or genetic manipulations, the ability to measure O(2) consumption efficiently from whole slices should advance our understanding of mitochondrial roles in physiology and neuropathology.
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Affiliation(s)
- Rosemary A Schuh
- Research Service, Maryland VA Healthcare System, Baltimore, Maryland, USA
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45
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Khairallah RJ, O'Shea KM, Galvao T, O'Connell K, Polster BM, Rosiers CD, Stanley WC. Dietary Supplementation with Docosahexanoic Acid or Arachidonic Acid Delay
Ca2+
‐Induced Permeability Transition Pore Opening in Cardiac Mitochondria. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1097.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Karen M O'Shea
- Medicine/CardiologyUniversity of MarylandBaltimoreBaltimoreMD
| | - Tatiana Galvao
- Medicine/CardiologyUniversity of MarylandBaltimoreBaltimoreMD
| | - Kelly O'Connell
- Medicine/CardiologyUniversity of MarylandBaltimoreBaltimoreMD
| | - Brian M Polster
- Medicine/CardiologyUniversity of MarylandBaltimoreBaltimoreMD
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46
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Gerencser AA, Mark KA, Hubbard AE, Divakaruni AS, Mehrabian Z, Nicholls DG, Polster BM. Real-time visualization of cytoplasmic calpain activation and calcium deregulation in acute glutamate excitotoxicity. J Neurochem 2009; 110:990-1004. [PMID: 19493161 DOI: 10.1111/j.1471-4159.2009.06194.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Although calpain (EC 3.4.22) protease activation was suggested to contribute to excitotoxic delayed calcium deregulation (DCD) via proteolysis of Na+/Ca2+ exchanger 3 (NCX3), cytoplasmic calpain activation in relation to DCD has never been visualized in real-time. We employed a calpain fluorescence resonance energy transfer substrate to simultaneously image calpain activation and calcium deregulation in live cortical neurons. A calpain inhibitor-sensitive decline in fluorescence resonance energy transfer was observed at 39 +/- 5 min after the occurrence of DCD in neurons exposed to continuous glutamate (100 microM). Inhibition of calpain by calpeptin did not delay the onset of DCD, recovery from DCD-like reversible calcium elevations, or cell death despite inhibiting alpha-spectrin processing by > 90%. NCXs reversed during glutamate exposure, the NCX antagonist KB-R7943 prolonged the time to DCD, and significant NCX3 cleavage following 90 min of glutamate exposure was not observed. Our findings suggest that robust calpain activation associated with acute glutamate toxicity occurs only after a sustained loss in calcium homeostasis. Processing of NCX3 or other calpain substrates is unlikely to be the primary cause of acute excitotoxicity in cortical neurons. However, a role for calpain as a contributing factor or in response to milder glutamate insults is not excluded.
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Abstract
Apoptosis-inducing factor (AIF)-deficient harlequin (Hq) mice undergo neurodegeneration associated with a 40-50% reduction in complex I level and activity. We tested the hypothesis that AIF and complex I regulate reactive oxygen species (ROS) production by brain mitochondria. Isolated Hq brain mitochondria oxidizing complex I substrates displayed no difference compared to wild type (WT) in basal ROS production, H2O2 removal, or ROS production stimulated by complex I inhibitors rotenone or 1-methyl-4-phenylpyridinium. In contrast, ROS production caused by reverse electron transfer to complex I was attenuated by approximately 50% in Hq mitochondria oxidizing the complex II substrate succinate. Basal and rotenone-stimulated rates of H2O2 release from in situ mitochondria did not differ between Hq and WT synaptosomes metabolizing glucose, nor did the level of in vivo oxidative protein carbonyl modifications detected in synaptosomes, brain mitochondria, or homogenates. Our results suggest that AIF does not directly modulate ROS release from brain mitochondria. In addition, they demonstrate that in contrast to ROS produced by mitochondria oxidizing succinate, ROS release from in situ synaptosomal mitochondria or from isolated brain mitochondria oxidizing complex I substrates is not proportional to the amount of complex I. These findings raise the important possibility that complex I contributes less to physiological ROS production by brain mitochondria than previously suggested.
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48
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Johnson-Cadwell LI, Jekabsons MB, Wang A, Polster BM, Nicholls DG. 'Mild Uncoupling' does not decrease mitochondrial superoxide levels in cultured cerebellar granule neurons but decreases spare respiratory capacity and increases toxicity to glutamate and oxidative stress. J Neurochem 2007; 101:1619-31. [PMID: 17437552 DOI: 10.1111/j.1471-4159.2007.04516.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cultured rat cerebellar granule neurons were incubated with low nanomolar concentrations of the protonophore carbonylcyanide-p-trifluoromethoxyphenyl hydrazone (FCCP) to test the hypothesis that 'mild uncoupling' could be neuroprotective by decreasing oxidative stress. To quantify the uncoupling, respiration and mitochondrial membrane potential (Deltapsi(m)) were determined in parallel as a function of FCCP concentration. Deltapsi(m) dropped by less than 10 mV before respiratory control was lost. Conditions for the valid estimation of matrix superoxide levels were determined from the rate of oxidation of the matrix-targeted fluorescent probe MitoSOX. No significant change in the level of matrix superoxide could be detected on addition of FCCP while respiratory control was retained, although cytoplasmic superoxide levels measured by dihydroethidium oxidation increased. 'Mild uncoupling' by 30 nmol/L FCCP did not alleviate neuronal dysregulation induced by glutathione depletion and significantly enhanced that due to menadione-induced oxidative stress. Low protonophore concentrations enhanced N-methyl-d-aspartate receptor-induced delayed calcium deregulation consistent with a decrease in the spare respiratory capacity available to match the bioenergetic demand of chronic receptor activation. It is concluded that the 'mild uncoupling' hypothesis is not supported by this model.
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Polster BM, Arze R, Lyttle MH, Nicholls DG, Hudson D. Solid Phase Synthesis of Dual Labeled Peptides: Development of Cell Permeable Calpain Specific Substrates. Int J Pept Res Ther 2006; 13:83-91. [PMID: 32214925 PMCID: PMC7088158 DOI: 10.1007/s10989-006-9049-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Accepted: 10/23/2006] [Indexed: 11/08/2022]
Abstract
A step-by-step evaluation of dual-labeled FRET substrates for the protease calpain is reported. The study led to cell permeable selections, with optimized specificity and effectiveness for the target enzyme, and improved stability to non-specific degrading enzymes.
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Affiliation(s)
- Brian M Polster
- 2Buck Institute for Age Research, 8001 Redwood Blvd., Novato, CA 94945 USA
| | - Rafael Arze
- 1Biosearch Technologies Inc, 81 Digital Drive, Novato, CA 94949 USA
| | - Matthew H Lyttle
- 1Biosearch Technologies Inc, 81 Digital Drive, Novato, CA 94949 USA
| | - David G Nicholls
- 2Buck Institute for Age Research, 8001 Redwood Blvd., Novato, CA 94945 USA
| | - Derek Hudson
- 1Biosearch Technologies Inc, 81 Digital Drive, Novato, CA 94949 USA
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Bonanni L, Chachar M, Jover-Mengual T, Li H, Jones A, Yokota H, Ofengeim D, Flannery RJ, Miyawaki T, Cho CH, Polster BM, Pypaert M, Hardwick JM, Sensi SL, Zukin RS, Jonas EA. Zinc-dependent multi-conductance channel activity in mitochondria isolated from ischemic brain. J Neurosci 2006; 26:6851-62. [PMID: 16793892 PMCID: PMC4758341 DOI: 10.1523/jneurosci.5444-05.2006] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Transient global ischemia is a neuronal insult that induces delayed cell death. A hallmark event in the early post-ischemic period is enhanced permeability of mitochondrial membranes. The precise mechanisms by which mitochondrial function is disrupted are, as yet, unclear. Here we show that global ischemia promotes alterations in mitochondrial membrane contact points, a rise in intramitochondrial Zn2+, and activation of large, multi-conductance channels in mitochondrial outer membranes by 1 h after insult. Mitochondrial channel activity was associated with enhanced protease activity and proteolytic cleavage of BCL-xL to generate its pro-death counterpart, deltaN-BCL-xL. The findings implicate deltaN-BCL-xL in large, multi-conductance channel activity. Consistent with this, large channel activity was mimicked by introduction of recombinant deltaN-BCL-xL to control mitochondria and blocked by introduction of a functional BCL-xL antibody to post-ischemic mitochondria via the patch pipette. Channel activity was also inhibited by nicotinamide adenine dinucleotide, indicative of a role for the voltage-dependent anion channel (VDAC) of the outer mitochondrial membrane. In vivo administration of the membrane-impermeant Zn2+ chelator CaEDTA before ischemia or in vitro application of the membrane-permeant Zn2+ chelator tetrakis-(2-pyridylmethyl) ethylenediamine attenuated channel activity, suggesting a requirement for Zn2+. These findings reveal a novel mechanism by which ischemic insults disrupt the functional integrity of the outer mitochondrial membrane and implicate deltaN-BCL-xL and VDAC in the large, Zn2+-dependent mitochondrial channels observed in post-ischemic hippocampal mitochondria.
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