1
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Zhou C, Tang F, Dong T, Liu HB, Deng L, Margolis RL, Li PP. Role of Bβ1 overexpression in the pathogenesis of SCA12. Mov Disord 2024. [PMID: 38798069 DOI: 10.1002/mds.29839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 04/14/2024] [Accepted: 05/07/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Spinocerebellar ataxia type 12 (SCA12) is a neurodegenerative disease caused by a CAG/CTG repeat expansion at the PPP2R2B locus. OBJECTIVE We investigated how the CAG repeat expansion within the PPP2R2B 7B7D transcript influences the expression of Bβ1 and a potential protein containing a long polyserine tract. METHODS Transcript and protein expression were measured using quantitative PCR (qPCR) Role of Bβ1 overexpression in the pathogenesis of SCA12 and Western blot, respectively, in an SK-N-MC cell model that overexpresses the full-length PPP2R2B 7B7D transcript. The apoptotic effect of a protein containing a long polyserine tract on SK-N-MC cells was evaluated using caspase 3/7 activity. RESULTS The CAG repeat expansion increases the expression of the PPP2R2B 7B7D transcript, as well as Bβ1 protein, in an SK-N-MC cell model in which the full-length PPP2R2B 7B7D transcript is overexpressed. The CAG repeat expansion within the 7B7D transcript is translated into a long polyserine tract that triggers apoptosis in SK-N-MC cells. CONCLUSIONS The SCA12 mutation leads to overexpression of PPP2R2B Bβ1 and to expression of a protein containing a long polyserine tract; both these effects potentially contribute to SCA12 pathogenesis. © 2024 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Chengqian Zhou
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Fan Tang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Tao Dong
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hans B Liu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Leon Deng
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Russell L Margolis
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Pan P Li
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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2
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Chen C, Merrill RA, Jong CJ, Strack S. Driving Mitochondrial Fission Improves Cognitive, but not Motor Deficits in a Mouse Model of Ataxia of Charlevoix-Saguenay. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01701-1. [PMID: 38735882 DOI: 10.1007/s12311-024-01701-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/01/2024] [Indexed: 05/14/2024]
Abstract
Autosomal-recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by loss-of-function mutation in the SACS gene, which encodes sacsin, a putative HSP70-HSP90 co-chaperone. Previous studies with Sacs knock-out (KO) mice and patient-derived fibroblasts suggested that SACSIN mutations inhibit the function of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1). This in turn resulted in mitochondrial hyperfusion and dysfunction. We experimentally tested this hypothesis by genetically manipulating the mitochondrial fission/fusion equilibrium, creating double KO (DKO) mice that also lack positive (PP2A/Bβ2) and negative (PKA/AKAP1) regulators of Drp1. Neither promoting mitochondrial fusion (Bβ2 KO) nor fission (Akap1 KO) influenced progression of motor symptoms in Sacs KO mice. However, our studies identified profound learning and memory deficits in aged Sacs KO mice. Moreover, this cognitive impairment was rescued in a gene dose-dependent manner by deletion of the Drp1 inhibitor PKA/Akap1. Our results are inconsistent with mitochondrial dysfunction as a primary pathogenic mechanism in ARSACS. Instead, they imply that promoting mitochondrial fission may be beneficial at later stages of the disease when pathology extends to brain regions subserving learning and memory.
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Affiliation(s)
- Chunling Chen
- Department of Neuroscience and Pharmacology, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA
| | - Ronald A Merrill
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, University of Iowa, Carver College of Medicine, Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA.
- Iowa Neuroscience Institute, Intellectual and Developmental Disabilities Research Center, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA.
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3
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Chen C, Merrill RA, Jong CJ, Strack S. Driving mitochondrial fission improves cognitive, but not motor deficits in a mouse model of Ataxia of Charlevoix-Saguenay. RESEARCH SQUARE 2024:rs.3.rs-4178088. [PMID: 38659734 PMCID: PMC11042405 DOI: 10.21203/rs.3.rs-4178088/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Autosomal-recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by loss-of-function mutation in the SACS gene, which encodes sacsin, a putative HSP70-HSP90 co-chaperone. Previous studies with Sacs knock-out (KO) mice and patient-derived fibroblasts suggested that SACSIN mutations inhibit the function of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1). This in turn resulted in mitochondrial hyperfusion and dysfunction. We experimentally tested this hypothesis by genetically manipulating the mitochondrial fission/fusion equilibrium, creating double KO (DKO) mice that also lack positive (PP2A/Bβ2) and negative (PKA/AKAP1) regulators of Drp1. Neither promoting mitochondrial fusion (Bβ2 KO) nor fission (Akap1 KO) influenced progression of motor symptoms in Sacs KO mice. However, our studies identified profound learning and memory deficits in aged Sacs KO mice. Moreover, this cognitive impairment was rescued in a gene dose-dependent manner by deletion of the Drp1 inhibitor PKA/Akap1. Our results are inconsistent with mitochondrial dysfunction as a primary pathogenic mechanism in ARSACS. Instead, they imply that promoting mitochondrial fission may be beneficial at later stages of the disease when pathology extends to brain regions subserving learning and memory.
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4
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Huan Y, Hao G, Shi Z, Liang Y, Dong Y, Quan H. The role of dynamin-related protein 1 in cerebral ischemia/hypoxia injury. Biomed Pharmacother 2023; 165:115247. [PMID: 37516018 DOI: 10.1016/j.biopha.2023.115247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/18/2023] [Accepted: 07/25/2023] [Indexed: 07/31/2023] Open
Abstract
Mitochondrial dysfunction, especially in terms of mitochondrial dynamics, has been reported to be closely associated with neuronal outcomes and neurological impairment in cerebral ischemia/hypoxia injury. Dynamin-related protein 1 (Drp1) is a cytoplasmic GTPase that mediates mitochondrial fission and participates in neuronal cell death, calcium signaling, and oxidative stress. The neuroprotective role of Drp1 inhibition has been confirmed in several central nervous system disease models, demonstrating that targeting Drp1 may shed light on novel approaches for the treatment of cerebral ischemia/hypoxia injury. In this review, we aimed to highlight the roles of Drp1 in programmed cell death, oxidative stress, mitophagy, and mitochondrial function to provide a better understanding of mitochondrial disturbances in cerebral ischemia/hypoxia injury, and we also summarize the advances in novel chemical compounds targeting Drp1 to provide new insights into potential therapies for cerebral ischemia/hypoxia injury.
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Affiliation(s)
- Yu Huan
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, China
| | - Guangzhi Hao
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, China
| | - Zuolin Shi
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, China
| | - Yong Liang
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, China
| | - Yushu Dong
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, China.
| | - Huilin Quan
- Department of Plastic Surgery, The First Hospital of China Medical University, Shenyang, China.
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5
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Bhatti JS, Kaur S, Mishra J, Dibbanti H, Singh A, Reddy AP, Bhatti GK, Reddy PH. Targeting dynamin-related protein-1 as a potential therapeutic approach for mitochondrial dysfunction in Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166798. [PMID: 37392948 DOI: 10.1016/j.bbadis.2023.166798] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/03/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that manifests its pathology through synaptic damage, mitochondrial abnormalities, microRNA deregulation, hormonal imbalance, increased astrocytes & microglia, accumulation of amyloid β (Aβ) and phosphorylated Tau in the brains of AD patients. Despite extensive research, the effective treatment of AD is still unknown. Tau hyperphosphorylation and mitochondrial abnormalities are involved in the loss of synapses, defective axonal transport and cognitive decline in patients with AD. Mitochondrial dysfunction is evidenced by enhanced mitochondrial fragmentation, impaired mitochondrial dynamics, mitochondrial biogenesis and defective mitophagy in AD. Hence, targeting mitochondrial proteins might be a promising therapeutic strategy in treating AD. Recently, dynamin-related protein 1 (Drp1), a mitochondrial fission protein, has gained attention due to its interactions with Aβ and hyperphosphorylated Tau, altering mitochondrial morphology, dynamics, and bioenergetics. These interactions affect ATP production in mitochondria. A reduction in Drp1 GTPase activity protects against neurodegeneration in AD models. This article provides a comprehensive overview of Drp1's involvement in oxidative damage, apoptosis, mitophagy, and axonal transport of mitochondria. We also highlighted the interaction of Drp1 with Aβ and Tau, which may contribute to AD progression. In conclusion, targeting Drp1 could be a potential therapeutic approach for preventing AD pathology.
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Affiliation(s)
- Jasvinder Singh Bhatti
- Laboratory of Translational Medicine and Nanotherapeutics, Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, India.
| | - Satinder Kaur
- Laboratory of Translational Medicine and Nanotherapeutics, Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, India
| | - Jayapriya Mishra
- Laboratory of Translational Medicine and Nanotherapeutics, Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, India
| | | | - Arti Singh
- Department of Pharmaceutics, ISF College of Pharmacy, Moga, Punjab, India
| | - Arubala P Reddy
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA.
| | - Gurjit Kaur Bhatti
- Department of Medical Lab Technology, University Institute of Applied Health Sciences, Chandigarh University, Mohali, India.
| | - P Hemachandra Reddy
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, 1301 Akron Ave, Lubbock, TX 79409, USA; Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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6
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Mitochondrial dynamics in macrophages: divide to conquer or unite to survive? Biochem Soc Trans 2023; 51:41-56. [PMID: 36815717 PMCID: PMC9988003 DOI: 10.1042/bst20220014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/29/2023] [Accepted: 02/02/2023] [Indexed: 02/24/2023]
Abstract
Mitochondria have long been appreciated as the metabolic hub of cells. Emerging evidence also posits these organelles as hubs for innate immune signalling and activation, particularly in macrophages. Macrophages are front-line cellular defenders against endogenous and exogenous threats in mammals. These cells use an array of receptors and downstream signalling molecules to respond to a diverse range of stimuli, with mitochondrial biology implicated in many of these responses. Mitochondria have the capacity to both divide through mitochondrial fission and coalesce through mitochondrial fusion. Mitochondrial dynamics, the balance between fission and fusion, regulate many cellular functions, including innate immune pathways in macrophages. In these cells, mitochondrial fission has primarily been associated with pro-inflammatory responses and metabolic adaptation, so can be considered as a combative strategy utilised by immune cells. In contrast, mitochondrial fusion has a more protective role in limiting cell death under conditions of nutrient starvation. Hence, fusion can be viewed as a cellular survival strategy. Here we broadly review the role of mitochondria in macrophage functions, with a focus on how regulated mitochondrial dynamics control different functional responses in these cells.
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7
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Shi W, Tan C, Liu C, Chen D. Mitochondrial fission mediated by Drp1-Fis1 pathway and neurodegenerative diseases. Rev Neurosci 2022; 34:275-294. [PMID: 36059131 DOI: 10.1515/revneuro-2022-0056] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/08/2022] [Indexed: 11/15/2022]
Abstract
In recent years, the role of mitochondrial dynamics in neurodegenerative diseases has becoming increasingly important. More and more evidences have shown that in pathological conditions, abnormal mitochondrial divisions, especially Drp1-Fis1-mediated divisions, play an important role in the occurrence and development of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, glaucoma, and other neurodegenerative diseases. This review highlights several new mechanisms of physiological fission of mitochondria and the difference/connection of physiological/pathological mitochondrial fission. In addition, we described the relationship between abnormal mitochondrial dynamics and neurodegenerative diseases in detail and emphatically summarized its detection indicators in basic experiments, trying to provide references for further mechanism exploration and therapeutic targets.
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Affiliation(s)
- Wenjia Shi
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, Hunan Province, China
| | - Cheng Tan
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, Hunan Province, China
| | - Can Liu
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, Hunan Province, China
| | - Dan Chen
- Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha 410013, Hunan Province, China
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8
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PP2A-B55: substrates and regulators in the control of cellular functions. Oncogene 2022; 41:1-14. [PMID: 34686773 DOI: 10.1038/s41388-021-02068-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/29/2021] [Accepted: 10/06/2021] [Indexed: 12/17/2022]
Abstract
PP2A is a major serine/threonine phosphatase class involved in the regulation of cell signaling through the removal of protein phosphorylation. This class of phosphatases is comprised of different heterotrimeric complexes displaying distinct substrate specificities. The present review will focus on one specific heterocomplex, the phosphatase PP2A-B55. Herein, we will report the direct substrates of this phosphatase identified to date, and its impact on different cell signaling cascades. We will additionally describe its negative regulation by its inhibitors Arpp19 and ENSA and their upstream kinase Greatwall. Finally, we will describe the essential molecular features defining PP2A-B55 substrate specificity that confer the correct temporal pattern of substrate dephosphorylation. The main objective of this review is to provide the reader with a unique source compiling all the knowledge of this particular holoenzyme that has evolved as a key enzyme for cell homeostasis and cancer development.
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9
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Sandal P, Jong CJ, Merrill RA, Song J, Strack S. Protein phosphatase 2A - structure, function and role in neurodevelopmental disorders. J Cell Sci 2021; 134:270819. [PMID: 34228795 DOI: 10.1242/jcs.248187] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neurodevelopmental disorders (NDDs), including intellectual disability (ID), autism and schizophrenia, have high socioeconomic impact, yet poorly understood etiologies. A recent surge of large-scale genome or exome sequencing studies has identified a multitude of mostly de novo mutations in subunits of the protein phosphatase 2A (PP2A) holoenzyme that are strongly associated with NDDs. PP2A is responsible for at least 50% of total Ser/Thr dephosphorylation in most cell types and is predominantly found as trimeric holoenzymes composed of catalytic (C), scaffolding (A) and variable regulatory (B) subunits. PP2A can exist in nearly 100 different subunit combinations in mammalian cells, dictating distinct localizations, substrates and regulatory mechanisms. PP2A is well established as a regulator of cell division, growth, and differentiation, and the roles of PP2A in cancer and various neurodegenerative disorders, such as Alzheimer's disease, have been reviewed in detail. This Review summarizes and discusses recent reports on NDDs associated with mutations of PP2A subunits and PP2A-associated proteins. We also discuss the potential impact of these mutations on the structure and function of the PP2A holoenzymes and the etiology of NDDs.
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Affiliation(s)
- Priyanka Sandal
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jianing Song
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
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10
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Gao F, Reynolds MB, Passalacqua KD, Sexton JZ, Abuaita BH, O'Riordan MXD. The Mitochondrial Fission Regulator DRP1 Controls Post-Transcriptional Regulation of TNF-α. Front Cell Infect Microbiol 2021; 10:593805. [PMID: 33520735 PMCID: PMC7840702 DOI: 10.3389/fcimb.2020.593805] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/30/2020] [Indexed: 12/12/2022] Open
Abstract
The mitochondrial network plays a critical role in the regulation of innate immune signaling and subsequent production of proinflammatory cytokines such as IFN-β and IL-1β. Dynamin-related protein 1 (DRP1) promotes mitochondrial fission and quality control to maintain cellular homeostasis during infection. However, mechanisms by which DRP1 and mitochondrial dynamics control innate immune signaling and the proinflammatory response are incompletely understood. Here we show that macrophage DRP1 is a positive regulator of TNF-α production during sterile inflammation or bacterial infection. Silencing macrophage DRP1 decreased mitochondrial fragmentation and TNF-α production upon stimulation with lipopolysaccharide (LPS) or methicillin-resistant Staphylococcus aureus (MRSA) infection. The defect in TNF-α induction could not be attributed to changes in gene expression. Instead, DRP1 was required for post-transcriptional control of TNF-α. In contrast, silencing DRP1 enhanced IL-6 and IL-1β production, indicating a distinct mechanism for DRP1-dependent TNF-α regulation. Our results highlight DRP1 as a key player in the macrophage pro-inflammatory response and point to its involvement in post-transcriptional control of TNF-α production.
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Affiliation(s)
- Fushan Gao
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Mack B Reynolds
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Karla D Passalacqua
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Jonathan Z Sexton
- Department of Internal Medicine, Gastroenterology, University of Michigan Medical School, Ann Arbor, MI, United States.,U-M Center for Drug Repurposing, University of Michigan, Ann Arbor, MI, United States.,Michigan Institute for Clinical and Health Research, University of Michigan, Ann Arbor, MI, United States.,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States
| | - Basel H Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Mary X D O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
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11
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Chen Y, Gong K, Xu Q, Meng J, Long T, Chang C, Wang Z, Liu W. Phosphoglycerate Mutase 5 Knockdown Alleviates Neuronal Injury After Traumatic Brain Injury Through Drp1-Mediated Mitochondrial Dysfunction. Antioxid Redox Signal 2021; 34:154-170. [PMID: 32253918 DOI: 10.1089/ars.2019.7982] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aims: Traumatic brain injury (TBI) is a major cause of disability and death, and a better understanding of the underlying mechanisms of mitochondrial dysfunction will provide important targets for preventing damage from neuronal insults. Phosphoglycerate mutase 5 (PGAM5) is localized to the mitochondrial outer-inner membrane contact sites, and the PGAM5-Drp1 pathway is involved in mitochondrial dysfunction and cell death. The purpose of this project was to evaluate the effects of PGAM5 on neuronal injury and mitochondrial dysfunction. Results: PGAM5 was overexpressed in mice subjected to TBI and in primary cortical neurons injured by mechanical equiaxial stretching. PGAM5 deficiency alleviated neuroinflammation, blocked Parkin, PINK1, and Drp1 translocation to mitochondria and abnormal phosphorylation of Drp1, mitochondrial ultrastructural changes, and nerve malfunction in TBI mouse model. PGAM5-shRNA (short hairpin RNA) reduced Drp1 translocation and activation, including dephosphorylation of p-Drp1 on Ser622 (human Drp1 Ser616) and phosphorylation of Drp1 on Ser643 (human Drp1 Ser637). The levels of inflammatory cytokines, the degree of mitochondrial impairment (mitochondrial membrane potential, ADP/ATP, AMP/ADP, antioxidant capacity), and neuronal injury in stretch-induced primary cortical neurons were reduced by blocking expression of PGAM5. The inhibition of PGAM5 is neuroprotective via attenuation of Drp1 activation, similar to that achieved by mitochondrial division inhibitor-1 (Mdivi1)-mediated Drp1 inhibition. Innovation and Conclusion: Our findings demonstrate the critical role of PGAM5 in progression of neuronal injury from TBI via Drp1 activation (dephosphorylation of p-Drp1 on Ser622 and phosphorylation of Drp1 on Ser643)-mediated mitochondrial dysfunction. The data may open a window for developing new drugs to prevent the neuropathology of TBI.
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Affiliation(s)
- Yuhua Chen
- Department of Central Laboratory, Xi'an Peihua University, Xi'an, China
| | - Kai Gong
- Department of Neurosurgery, First Affiliated Hospital of Xia'men University, Xia'men, China
| | - Quanhua Xu
- Department of Neurosurgery, Bijie First People's Hospital, Bijie, China
| | - Jiao Meng
- Department of Central Laboratory, Xi'an Peihua University, Xi'an, China
| | - Tianlin Long
- Department of Neurosurgery, Bijie First People's Hospital, Bijie, China
| | - Cuicui Chang
- Department of Central Laboratory, Xi'an Peihua University, Xi'an, China
| | - Zhanxiang Wang
- Department of Neurosurgery, First Affiliated Hospital of Xia'men University, Xia'men, China
| | - Wei Liu
- Department of Neurosurgery, Bijie First People's Hospital, Bijie, China
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12
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Chen Y, Guo S, Tang Y, Mou C, Hu X, Shao F, Yan W, Wu Q. Mitochondrial Fusion and Fission in Neuronal Death Induced by Cerebral Ischemia-Reperfusion and Its Clinical Application: A Mini-Review. Med Sci Monit 2020; 26:e928651. [PMID: 33156817 PMCID: PMC7654336 DOI: 10.12659/msm.928651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mitochondria are highly dynamic organelles which are joined by mitochondrial fusion and divided by mitochondrial fission. The balance of mitochondrial fusion and fission plays a critical role in maintaining the normal function of neurons, of which the processes are both mediated by several proteins activated by external stimulation. Cerebral ischemia-reperfusion (I/R) injury can disrupt the balance of mitochondrial fusion and fission through regulating the expression and post-translation modification of fusion- and fission-related proteins, thereby destroying homeostasis of the intracellular environment and causing neuronal death. Furthermore, human intervention in fusion- and fission-related proteins can influence the function of neurons and change the outcomes of cerebral I/R injury. In recent years, researchers have found that mitochondrial dysfunction was one of the main factors involved in I/R, and mitochondria is an attractive target in I/R neuroprotection. Therefore, mitochondrial-targeted therapy of the nervous system for I/R gradually started from basic study to clinical application. In the present review, we highlight recent progress in mitochondria fusion and fission in neuronal death induced by cerebral I/R to help understanding the regulatory factors and signaling networks of aberrant mitochondrial fusion and fission contributing to neuronal death during I/R, as well as the potential neuroprotective therapeutics targeting mitochondrial dynamics, which may help clinical treatment and development of relevant dugs.
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Affiliation(s)
- Yike Chen
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China (mainland)
| | - Songxue Guo
- Department of Plastic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China (mainland)
| | - Yajuan Tang
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China (mainland)
| | - Chaohui Mou
- Department of Neurosurgery, Taizhou First People's Hospital, Taizhou, Zhejiang, China (mainland)
| | - Xinben Hu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China (mainland)
| | - Fangjie Shao
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China (mainland)
| | - Wei Yan
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China (mainland)
| | - Qun Wu
- Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China (mainland)
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13
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Deletion of a Neuronal Drp1 Activator Protects against Cerebral Ischemia. J Neurosci 2020; 40:3119-3129. [PMID: 32144179 DOI: 10.1523/jneurosci.1926-19.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 11/21/2022] Open
Abstract
Mitochondrial fission catalyzed by dynamin-related protein 1 (Drp1) is necessary for mitochondrial biogenesis and maintenance of healthy mitochondria. However, excessive fission has been associated with multiple neurodegenerative disorders, and we recently reported that mice with smaller mitochondria are sensitized to ischemic stroke injury. Although pharmacological Drp1 inhibition has been put forward as neuroprotective, the specificity and mechanism of the inhibitor used is controversial. Here, we provide genetic evidence that Drp1 inhibition is neuroprotective. Drp1 is activated by dephosphorylation of an inhibitory phosphorylation site, Ser637. We identify Bβ2, a mitochondria-localized protein phosphatase 2A (PP2A) regulatory subunit, as a neuron-specific Drp1 activator in vivo Bβ2 KO mice of both sexes display elongated mitochondria in neurons and are protected from cerebral ischemic injury. Functionally, deletion of Bβ2 and maintained Drp1 Ser637 phosphorylation improved mitochondrial respiratory capacity, Ca2+ homeostasis, and attenuated superoxide production in response to ischemia and excitotoxicity in vitro and ex vivo Last, deletion of Bβ2 rescued excessive stroke damage associated with dephosphorylation of Drp1 S637 and mitochondrial fission. These results indicate that the state of mitochondrial connectivity and PP2A/Bβ2-mediated dephosphorylation of Drp1 play a critical role in determining the severity of cerebral ischemic injury. Therefore, Bβ2 may represent a target for prophylactic neuroprotective therapy in populations at high risk of stroke.SIGNIFICANCE STATEMENT With recent advances in clinical practice including mechanical thrombectomy up to 24 h after the ischemic event, there is resurgent interest in neuroprotective stroke therapies. In this study, we demonstrate reduced stroke damage in the brain of mice lacking the Bβ2 regulatory subunit of protein phosphatase 2A, which we have shown previously acts as a positive regulator of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1). Importantly, we provide evidence that deletion of Bβ2 can rescue excessive ischemic damage in mice lacking the mitochondrial PKA scaffold AKAP1, apparently via opposing effects on Drp1 S637 phosphorylation. These results highlight reversible phosphorylation in bidirectional regulation of Drp1 activity and identify Bβ2 as a potential pharmacological target to protect the brain from stroke injury.
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Abstract
Owing to their ability to efficiently generate ATP required to sustain normal cell function, mitochondria are often considered the 'powerhouses of the cell'. However, our understanding of the role of mitochondria in cell biology recently expanded when we recognized that they are key platforms for a plethora of cell signalling cascades. This functional versatility is tightly coupled to constant reshaping of the cellular mitochondrial network in a series of processes, collectively referred to as mitochondrial membrane dynamics and involving organelle fusion and fission (division) as well as ultrastructural remodelling of the membrane. Accordingly, mitochondrial dynamics influence and often orchestrate not only metabolism but also complex cell signalling events, such as those involved in regulating cell pluripotency, division, differentiation, senescence and death. Reciprocally, mitochondrial membrane dynamics are extensively regulated by post-translational modifications of its machinery and by the formation of membrane contact sites between mitochondria and other organelles, both of which have the capacity to integrate inputs from various pathways. Here, we discuss mitochondrial membrane dynamics and their regulation and describe how bioenergetics and cellular signalling are linked to these dynamic changes of mitochondrial morphology.
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Abstract
Significance: In addition to their classical role in cellular ATP production, mitochondria are of key relevance in various (patho)physiological mechanisms including second messenger signaling, neuro-transduction, immune responses and death induction. Recent Advances: Within cells, mitochondria are motile and display temporal changes in internal and external structure ("mitochondrial dynamics"). During the last decade, substantial empirical and in silico evidence was presented demonstrating that mitochondrial dynamics impacts on mitochondrial function and vice versa. Critical Issues: However, a comprehensive and quantitative understanding of the bidirectional links between mitochondrial external shape, internal structure and function ("morphofunction") is still lacking. The latter particularly hampers our understanding of the functional properties and behavior of individual mitochondrial within single living cells. Future Directions: In this review we discuss the concept of mitochondrial morphofunction in mammalian cells, primarily using experimental evidence obtained within the last decade. The topic is introduced by briefly presenting the central role of mitochondria in cell physiology and the importance of the mitochondrial electron transport chain (ETC) therein. Next, we summarize in detail how mitochondrial (ultra)structure is controlled and discuss empirical evidence regarding the equivalence of mitochondrial (ultra)structure and function. Finally, we provide a brief summary of how mitochondrial morphofunction can be quantified at the level of single cells and mitochondria, how mitochondrial ultrastructure/volume impacts on mitochondrial bioreactions and intramitochondrial protein diffusion, and how mitochondrial morphofunction can be targeted by small molecules.
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Affiliation(s)
- Elianne P. Bulthuis
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Merel J.W. Adjobo-Hermans
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Peter H.G.M. Willems
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Werner J.H. Koopman
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
- Address correspondence to: Dr. Werner J.H. Koopman, Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, P.O. Box 9101, Nijmegen NL-6500 HB, The Netherlands
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16
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Adaniya SM, O-Uchi J, Cypress MW, Kusakari Y, Jhun BS. Posttranslational modifications of mitochondrial fission and fusion proteins in cardiac physiology and pathophysiology. Am J Physiol Cell Physiol 2019; 316:C583-C604. [PMID: 30758993 DOI: 10.1152/ajpcell.00523.2018] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial fragmentation frequently occurs in chronic pathological conditions as seen in various human diseases. In fact, abnormal mitochondrial morphology and mitochondrial dysfunction are hallmarks of heart failure (HF) in both human patients and HF animal models. A link between mitochondrial fragmentation and cardiac pathologies has been widely proposed, but the physiological relevance of mitochondrial fission and fusion in the heart is still unclear. Recent studies have increasingly shown that posttranslational modifications (PTMs) of fission and fusion proteins are capable of directly modulating the stability, localization, and/or activity of these proteins. These PTMs include phosphorylation, acetylation, ubiquitination, conjugation of small ubiquitin-like modifier proteins, O-linked-N-acetyl-glucosamine glycosylation, and proteolysis. Thus, understanding the PTMs of fission and fusion proteins may allow us to understand the complexities that determine the balance of mitochondrial fission and fusion as well as mitochondrial function in various cell types and organs including cardiomyocytes and the heart. In this review, we summarize present knowledge regarding the function and regulation of mitochondrial fission and fusion in cardiomyocytes, specifically focusing on the PTMs of each mitochondrial fission/fusion protein. We also discuss the molecular mechanisms underlying abnormal mitochondrial morphology in HF and their contributions to the development of cardiac diseases, highlighting the crucial roles of PTMs of mitochondrial fission and fusion proteins. Finally, we discuss the future potential of manipulating PTMs of fission and fusion proteins as a therapeutic strategy for preventing and/or treating HF.
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Affiliation(s)
- Stephanie M Adaniya
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota.,Cardiovascular Research Center, Department of Medicine, Rhode Island Hospital and the Alpert Medical School of Brown University , Providence, Rhode Island
| | - Jin O-Uchi
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota
| | - Michael W Cypress
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota
| | - Yoichiro Kusakari
- Department of Cell Physiology, The Jikei University School of Medicine , Tokyo , Japan
| | - Bong Sook Jhun
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota
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17
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Jhun BS, O-Uchi J, Adaniya SM, Cypress MW, Yoon Y. Adrenergic Regulation of Drp1-Driven Mitochondrial Fission in Cardiac Physio-Pathology. Antioxidants (Basel) 2018; 7:antiox7120195. [PMID: 30567380 PMCID: PMC6316402 DOI: 10.3390/antiox7120195] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 12/28/2022] Open
Abstract
Abnormal mitochondrial morphology, especially fragmented mitochondria, and mitochondrial dysfunction are hallmarks of a variety of human diseases including heart failure (HF). Although emerging evidence suggests a link between mitochondrial fragmentation and cardiac dysfunction, it is still not well described which cardiac signaling pathway regulates mitochondrial morphology and function under pathophysiological conditions such as HF. Mitochondria change their shape and location via the activity of mitochondrial fission and fusion proteins. This mechanism is suggested as an important modulator for mitochondrial and cellular functions including bioenergetics, reactive oxygen species (ROS) generation, spatiotemporal dynamics of Ca2+ signaling, cell growth, and death in the mammalian cell- and tissue-specific manners. Recent reports show that a mitochondrial fission protein, dynamin-like/related protein 1 (DLP1/Drp1), is post-translationally modified via cell signaling pathways, which control its subcellular localization, stability, and activity in cardiomyocytes/heart. In this review, we summarize the possible molecular mechanisms for causing post-translational modifications (PTMs) of DLP1/Drp1 in cardiomyocytes, and further discuss how these PTMs of DLP1/Drp1 mediate abnormal mitochondrial morphology and mitochondrial dysfunction under adrenergic signaling activation that contributes to the development and progression of HF.
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Affiliation(s)
- Bong Sook Jhun
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Jin O-Uchi
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Stephanie M Adaniya
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
- Cardiovascular Research Center, Rhode Island Hospital, Providence, RI 02903, USA.
- Department of Medicine, Division of Cardiology, the Alpert Medical School of Brown University, Providence, RI 02903, USA.
| | - Michael W Cypress
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Yisang Yoon
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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Qi Z, Huang Z, Xie F, Chen L. Dynamin-related protein 1: A critical protein in the pathogenesis of neural system dysfunctions and neurodegenerative diseases. J Cell Physiol 2018; 234:10032-10046. [PMID: 30515821 DOI: 10.1002/jcp.27866] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/14/2018] [Indexed: 02/06/2023]
Abstract
Mitochondria play a key role in the maintenance of neuronal function by continuously providing energy. Here, we will give a detailed review about the recent developments in regards to dynamin-related protein 1 (Drp1) induced unbalanced mitochondrial dynamics, excessive mitochondrial division, and neuronal injury in neural system dysfunctions and neurodegenerative diseases, including the Drp1 knockout induced mice embryonic death, the dysfunction of the Drp1-dependent mitochondrial division induced neuronal cell apoptosis and impaired neuronal axonal transportation, the abnormal interaction between Drp1 and amyloid β (Aβ) in Alzheimer's disease (AD), the mutant Huntingtin (Htt) in Huntington's disease (HD), and the Drp1-associated pathogenesis of other neurodegenerative diseases such as Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Drp1 is required for mitochondrial division determining the size, shape, distribution, and remodeling as well as maintaining of mitochondrial integrity in mammalian cells. In addition, increasing reports indicate that the Drp1 is involved in some cellular events of neuronal cells causing some neural system dysfunctions and neurodegenerative diseases, including impaired mitochondrial dynamics, apoptosis, and several posttranslational modification induced increased mitochondrial divisions. Recent studies also revealed that the Drp1 can interact with Aβ, phosphorylated τ, and mutant Htt affecting the mitochondrial shape, size, distribution, axonal transportation, and energy production in the AD and HD neuronal cells. These changes can affect the health of mitochondria and the function of synapses causing neuronal injury and eventually leading to the dysfunction of memory, cognitive impairment, resting tremor, posture instability, involuntary movements, and progressive muscle atrophy and paralysis in patients.
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Affiliation(s)
- Zhihao Qi
- Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, University of South China, Hengyang, China
| | - Zhen Huang
- Department of Pharmacy, The First Affiliated Hospital, University of South China, Hengyang, China
| | - Feng Xie
- Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, University of South China, Hengyang, China
| | - Linxi Chen
- Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, University of South China, Hengyang, China
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19
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Sugo M, Kimura H, Arasaki K, Amemiya T, Hirota N, Dohmae N, Imai Y, Inoshita T, Shiba-Fukushima K, Hattori N, Cheng J, Fujimoto T, Wakana Y, Inoue H, Tagaya M. Syntaxin 17 regulates the localization and function of PGAM5 in mitochondrial division and mitophagy. EMBO J 2018; 37:embj.201798899. [PMID: 30237312 DOI: 10.15252/embj.201798899] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 08/03/2018] [Accepted: 08/13/2018] [Indexed: 12/26/2022] Open
Abstract
PGAM5, a mitochondrial protein phosphatase that is genetically and biochemically linked to PINK1, facilitates mitochondrial division by dephosphorylating the mitochondrial fission factor Drp1. At the onset of mitophagy, PGAM5 is cleaved by PARL, a rhomboid protease that degrades PINK1 in healthy cells, and the cleaved form facilitates the engulfment of damaged mitochondria by autophagosomes by dephosphorylating the mitophagy receptor FUNDC1. Here, we show that the function and localization of PGAM5 are regulated by syntaxin 17 (Stx17), a mitochondria-associated membrane/mitochondria protein implicated in mitochondrial dynamics in fed cells and autophagy in starved cells. In healthy cells, loss of Stx17 causes PGAM5 aggregation within mitochondria and thereby failure of the dephosphorylation of Drp1, leading to mitochondrial elongation. In Parkin-mediated mitophagy, Stx17 is prerequisite for PGAM5 to interact with FUNDC1. Our results reveal that the Stx17-PGAM5 axis plays pivotal roles in mitochondrial division and PINK1/Parkin-mediated mitophagy.
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Affiliation(s)
- Masashi Sugo
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hana Kimura
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Toshiki Amemiya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Naohiko Hirota
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Yuzuru Imai
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tsuyoshi Inoshita
- Department of Treatment and Research in Multiple Sclerosis and Neuro-intractable Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kahori Shiba-Fukushima
- Department of Treatment and Research in Multiple Sclerosis and Neuro-intractable Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Nobutaka Hattori
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Treatment and Research in Multiple Sclerosis and Neuro-intractable Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Jinglei Cheng
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuichi Wakana
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hiroki Inoue
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Mitsuo Tagaya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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20
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Zhang L, Ma P, Guan Q, Meng L, Su L, Wang L, Zhao J, Ji S. Protein phosphatase 2A regulates the p38 signaling pathway to affect the migration of astrocytes. Mol Med Rep 2018; 18:4328-4334. [PMID: 30152844 PMCID: PMC6172367 DOI: 10.3892/mmr.2018.9425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 03/08/2018] [Indexed: 11/30/2022] Open
Abstract
The aim of the present study was to investigate the effect and mechanism of protein phosphatase 2A (PP2A) on the migration of astrocytes. The primary astrocytes of neonatal mice were isolated and cultured in vitro, and treated with the PP2A activator D-erythro-sphingosine (DES) (activated group) or inhibitor okadaic acid (inhibitory group). The control group was treated with equal amounts of dimethyl sulfoxide. The activity of PP2A in the cells was detected using a commercial kit and the migration of cells was investigated using a Transwell migration assay. The protein expression of p38, phosphorylated (p)-p38, matrix metalloproteinase (MMP)-2 and MMP-9 was detected by western blotting. Cell migration and the protein expression of p38, p-p38, MMP-2 and MMP-9 was also determined following treatment of astrocytes with the p38 signaling pathway inhibitor SB202190 with or without the PP2A activator DES. The results demonstrated that the activity of PP2A in the PP2A inhibitory group was significantly decreased compared with the control group, while that of the PP2A-activated cells was significantly increased compared with the control. The protein levels of MMP-2 and MMP-9 in the PP2A inhibitory group astrocytes were significantly decreased compared with the control group, while PP2A-activated astrocytes exhibited significantly increased levels of these proteins. By contrast, the p-p38 level in PP2A inhibitory group astrocytes was significantly increased compared with the control group, while astrocytes in the activated group exhibited significantly lower levels compared with the control group. Furthermore, the cell migration ability, and MMP-2 and MMP-9 protein levels, of astrocytes that received combined treatment with SB202190 and the PP2A activator DES were significantly increased compared with the levels in astrocytes treated with SB202190 alone. The results of the current study indicate that PP2A may negatively regulate the p38 signaling pathway to promote astrocyte migration.
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Affiliation(s)
- Lijun Zhang
- Department of Neurology, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Pengju Ma
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Qingkai Guan
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Lei Meng
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Linlin Su
- Department of Neurology, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Lina Wang
- Department of Neurology, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Jianhua Zhao
- Department of Neurology, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Sibei Ji
- Department of Neurology, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
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AKAP1 Protects from Cerebral Ischemic Stroke by Inhibiting Drp1-Dependent Mitochondrial Fission. J Neurosci 2018; 38:8233-8242. [PMID: 30093535 PMCID: PMC6146498 DOI: 10.1523/jneurosci.0649-18.2018] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/29/2018] [Accepted: 08/01/2018] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial fission and fusion impact numerous cellular functions and neurons are particularly sensitive to perturbations in mitochondrial dynamics. Here we describe that male mice lacking the mitochondrial A-kinase anchoring protein 1 (AKAP1) exhibit increased sensitivity in the transient middle cerebral artery occlusion model of focal ischemia. At the ultrastructural level, AKAP1-/- mice have smaller mitochondria and increased contacts between mitochondria and the endoplasmic reticulum in the brain. Mechanistically, deletion of AKAP1 dysregulates complex II of the electron transport chain, increases superoxide production, and impairs Ca2+ homeostasis in neurons subjected to excitotoxic glutamate. Ca2+ deregulation in neurons lacking AKAP1 can be attributed to loss of inhibitory phosphorylation of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1) at the protein kinase A (PKA) site Ser637. Our results indicate that inhibition of Drp1-dependent mitochondrial fission by the outer mitochondrial AKAP1/PKA complex protects neurons from ischemic stroke by maintaining respiratory chain activity, inhibiting superoxide production, and delaying Ca2+ deregulation. They also provide the first genetic evidence that Drp1 inhibition may be of therapeutic relevance for the treatment of stroke and neurodegeneration.SIGNIFICANCE STATEMENT Previous work suggests that activation of dynamin-related protein 1 (Drp1) and mitochondrial fission contribute to ischemic injury in the brain. However, the specificity and efficacy of the pharmacological Drp1 inhibitor mdivi-1 that was used has now been discredited by several high-profile studies. Our report is timely and highly impactful because it provides the first evidence that genetic disinhibition of Drp1 via knock-out of the mitochondrial protein kinase A (PKA) scaffold AKAP1 exacerbates stroke injury in mice. Mechanistically, we show that electron transport deficiency, increased superoxide production, and Ca2+ overload result from genetic disinhibition of Drp1. In summary, our work settles current controversies regarding the role of mitochondrial fission in neuronal injury, provides mechanisms, and suggests that fission inhibitors hold promise as future therapeutic agents.
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Lu Y, Chen W, Lin C, Wang J, Zhu M, Chen J, Miao C. The protective effects of propofol against CoCl 2-induced HT22 cell hypoxia injury via PP2A/CAMKIIα/nNOS pathway. BMC Anesthesiol 2017; 17:32. [PMID: 28241801 PMCID: PMC5329915 DOI: 10.1186/s12871-017-0327-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 02/20/2017] [Indexed: 02/07/2023] Open
Abstract
Background Perioperative cerebral ischemia/hypoxia could induce hippocampal injury and has been reported to induce cognitive impairment. In this study, we used cobalt chloride (CoCl2) to build a hypoxia model in mouse hippocampal cell lines. Propofol, a widely used intravenous anesthetic agent, has been demonstrated to have neuroprotective effect. Here, we explored whether and how propofol attenuated CoCl2-induced mouse hippocampal HT22 cell injury. Methods Mouse hippocampal HT22 cells were pretreated with propofol, and then stimulated with CoCl2. Cell viability was measured by cell counting kit 8 (CCK8). The effect of propofol on CoCl2-modulated expressions of B-cell lymphoma 2 (Bcl-2), BAX, cleaved caspase 3, phosphatase A2 (PP2A), and the phosphorylation of Ca2+/Calmodulin (CaM)-dependent protein kinase II (pCAMKIIα), neuron nitric oxide synthase at Ser1412 (pnNOS-Ser1412), neuron nitric oxide synthase at Ser847 (pnNOS-Ser847) were detected by Western blot analysis. Results Compared with control, CoCl2 treatment could significantly decrease cell viability, which could be reversed by propofol. Further, we found CoCl2 treatment could up-regulate the expression of PP2A, BAX, cleaved caspase three and cause the phosphorylation of nNOS-Ser1412, but it down-regulated the expression of Bcl-2 and the phosphorylation of CAMKIIα and nNOS-Ser847. More importantly, these CoCl2-mediated effects were attentuated by propofol. In addition, we demonstrated that propofol could exert similar effect to that of the PP2A inhibitor (okadaic acid). Further, the PP2A activator (FTY720) and the CAMKIIα inhibitor (KN93) could reverse the neuroprotective effect of propofol. Conclusion Our data indicated that propofol could attenuate CoCl2-induced HT22 cells hypoxia injury via PP2A/CAMKIIα/nNOS pathway.
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Affiliation(s)
- Yan Lu
- Department of Anesthesiology, Fudan University Shanghai Cancer Centre, No. 270 DongAn Road, Shanghai, 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Wei Chen
- Department of Anesthesiology, Fudan University Shanghai Cancer Centre, No. 270 DongAn Road, Shanghai, 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Chen Lin
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China.,Department of Medical Oncology, Fudan University Shanghai Cancer Centre, No. 270 DongAn Road, Shanghai, 200032, People's Republic of China
| | - Jiaqiang Wang
- Department of Anesthesiology, Fudan University Shanghai Cancer Centre, No. 270 DongAn Road, Shanghai, 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Minmin Zhu
- Department of Anesthesiology, Fudan University Shanghai Cancer Centre, No. 270 DongAn Road, Shanghai, 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Jiawei Chen
- Department of Anesthesiology, Fudan University Shanghai Cancer Centre, No. 270 DongAn Road, Shanghai, 200032, People's Republic of China. .,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China.
| | - Changhong Miao
- Department of Anesthesiology, Fudan University Shanghai Cancer Centre, No. 270 DongAn Road, Shanghai, 200032, People's Republic of China. .,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China.
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23
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Flippo KH, Strack S. Mitochondrial dynamics in neuronal injury, development and plasticity. J Cell Sci 2017; 130:671-681. [PMID: 28154157 DOI: 10.1242/jcs.171017] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondria fulfill numerous cellular functions including ATP production, Ca2+ buffering, neurotransmitter synthesis and degradation, ROS production and sequestration, apoptosis and intermediate metabolism. Mitochondrial dynamics, a collective term for the processes of mitochondrial fission, fusion and transport, governs mitochondrial function and localization within the cell. Correct balance of mitochondrial dynamics is especially important in neurons as mutations in fission and fusion enzymes cause peripheral neuropathies and impaired development of the nervous system in humans. Regulation of mitochondrial dynamics is partly accomplished through post-translational modification of mitochondrial fission and fusion enzymes, in turn influencing mitochondrial bioenergetics and transport. The importance of post-translational regulation is highlighted by numerous neurodegenerative disorders associated with post-translational modification of the mitochondrial fission enzyme Drp1. Not surprisingly, mitochondrial dynamics also play an important physiological role in the development of the nervous system and synaptic plasticity. Here, we highlight recent findings underlying the mechanisms and regulation of mitochondrial dynamics in relation to neurological disease, as well as the development and plasticity of the nervous system.
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Affiliation(s)
- Kyle H Flippo
- Department of Pharmacology, University of Iowa, Iowa City, USA
| | - Stefan Strack
- Department of Pharmacology, University of Iowa, Iowa City, USA
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24
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Drp1-Dependent Mitochondrial Fission Plays Critical Roles in Physiological and Pathological Progresses in Mammals. Int J Mol Sci 2017; 18:ijms18010144. [PMID: 28098754 PMCID: PMC5297777 DOI: 10.3390/ijms18010144] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/28/2016] [Accepted: 01/09/2017] [Indexed: 12/22/2022] Open
Abstract
Current research has demonstrated that mitochondrial morphology, distribution, and function are maintained by the balanced regulation of mitochondrial fission and fusion, and perturbation of the homeostasis between these processes has been related to cell or organ dysfunction and abnormal mitochondrial redistribution. Abnormal mitochondrial fusion induces the fragmentation of mitochondria from a tubular morphology into pieces; in contrast, perturbed mitochondrial fission results in the fusion of adjacent mitochondria. A member of the dynamin family of large GTPases, dynamin-related protein 1 (Drp1), effectively influences cell survival and apoptosis by mediating the mitochondrial fission process in mammals. Drp1-dependent mitochondrial fission is an intricate process regulating both cellular and organ dynamics, including development, apoptosis, acute organ injury, and various diseases. Only after clarification of the regulative mechanisms of this critical protein in vivo and in vitro will it set a milestone for preventing mitochondrial fission related pathological processes and refractory diseases.
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Regulation of Mitochondrial Dynamics and Autophagy by the Mitochondria-Associated Membrane. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:33-47. [DOI: 10.1007/978-981-10-4567-7_3] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ren H, Yang B, Ruiz JA, Efe O, Ilori TO, Sands JM, Klein JD. Phosphatase inhibition increases AQP2 accumulation in the rat IMCD apical plasma membrane. Am J Physiol Renal Physiol 2016; 311:F1189-F1197. [PMID: 27488997 PMCID: PMC5210195 DOI: 10.1152/ajprenal.00150.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/01/2016] [Indexed: 01/11/2023] Open
Abstract
Vasopressin triggers the phosphorylation and apical plasma membrane accumulation of aquaporin 2 (AQP2), and it plays an essential role in urine concentration. Vasopressin, acting through protein kinase A, phosphorylates AQP2. However, the phosphorylation state of AQP2 could also be affected by the action of protein phosphatases (PPs). Rat inner medullas (IM) were incubated with calyculin (PP1 and PP2A inhibitor, 50 nM) or tacrolimus (PP2B inhibitor, 100 nM). Calyculin did not affect total AQP2 protein abundance (by Western blot) but did significantly increase the abundances of pS256-AQP2 and pS264-AQP2. It did not change pS261-AQP2 or pS269-AQP2. Calyculin significantly enhanced the membrane accumulation (by biotinylation) of total AQP2, pS256-AQP2, and pS264-AQP2. Likewise, immunohistochemistry showed an increase in the apical plasma membrane association of pS256-AQP2 and pS264-AQP2 in calyculin-treated rat IM. Tacrolimus also did not change total AQP2 abundance but significantly increased the abundances of pS261-AQP2 and pS264-AQP2. In contrast to calyculin, tacrolimus did not change the amount of total AQP2 in the plasma membrane (by biotinylation and immunohistochemistry). Tacrolimus did increase the expression of pS264-AQP2 in the apical plasma membrane (by immunohistochemistry). In conclusion, PP1/PP2A regulates the phosphorylation and apical plasma membrane accumulation of AQP2 differently than PP2B. Serine-264 of AQP2 is a phosphorylation site that is regulated by both PP1/PP2A and PP2B. This dual regulatory pathway may suggest a previously unappreciated role for multiple phosphatases in the regulation of urine concentration.
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Affiliation(s)
- Huiwen Ren
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
- Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China; and
| | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China; and
| | - Joseph A Ruiz
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
| | - Orhan Efe
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
| | - Titilayo O Ilori
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
| | - Jeff M Sands
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Janet D Klein
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia;
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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Kim DI, Lee KH, Oh JY, Kim JS, Han HJ. Relationship Between β-Amyloid and Mitochondrial Dynamics. Cell Mol Neurobiol 2016; 37:955-968. [PMID: 27766447 DOI: 10.1007/s10571-016-0434-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/13/2016] [Indexed: 01/29/2023]
Abstract
Mitochondria as dynamic organelles undergo morphological changes through the processes of fission and fusion which are major factors regulating their functions. A disruption in the balance of mitochondrial dynamics induces functional disorders in mitochondria such as failed energy production and the generation of reactive oxygen species, which are closely related to pathophysiological changes associated with Alzheimer's disease (AD). Recent studies have demonstrated a relationship between abnormalities in mitochondrial dynamics and impaired mitochondrial function, clarifying the effects of morphofunctional aberrations which promote neuronal cell death in AD. Several possible signaling pathways have been suggested for a better understanding of the mechanism behind the key molecules regulating mitochondrial morphologies. However, the exact machinery involved in mitochondrial dynamics still has yet to be elucidated. This paper reviews the current knowledge on signaling mechanisms involved in mitochondrial dynamics and the significance of mitochondrial dynamics in controlling associated functions in neurodegenerative diseases, particularly in AD.
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Affiliation(s)
- Dah Ihm Kim
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - Ki Hoon Lee
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - Ji Young Oh
- Department of Agricultural Biotechnology, Animal Biotechnology Major, and Research Institute of Agriculture and Life Science, Seoul National University, Seoul, 08826, South Korea
| | - Jun Sung Kim
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - Ho Jae Han
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea. .,BK21 PLUS Creative Veterinary Research Center, Seoul National University, Seoul, 08826, South Korea.
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Abstract
Protein phosphatase 2A (PP2A) plays a critical multi-faceted role in the regulation of the cell cycle. It is known to dephosphorylate over 300 substrates involved in the cell cycle, regulating almost all major pathways and cell cycle checkpoints. PP2A is involved in such diverse processes by the formation of structurally distinct families of holoenzymes, which are regulated spatially and temporally by specific regulators. Here, we review the involvement of PP2A in the regulation of three cell signaling pathways: wnt, mTOR and MAP kinase, as well as the G1→S transition, DNA synthesis and mitotic initiation. These processes are all crucial for proper cell survival and proliferation and are often deregulated in cancer and other diseases.
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Affiliation(s)
- Nathan Wlodarchak
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
| | - Yongna Xing
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
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Plácido AI, Pereira CMF, Correira SC, Carvalho C, Oliveira CR, Moreira PI. Phosphatase 2A Inhibition Affects Endoplasmic Reticulum and Mitochondria Homeostasis Via Cytoskeletal Alterations in Brain Endothelial Cells. Mol Neurobiol 2016; 54:154-168. [DOI: 10.1007/s12035-015-9640-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/15/2015] [Indexed: 12/30/2022]
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Dagda RK, Das Banerjee T. Role of protein kinase A in regulating mitochondrial function and neuronal development: implications to neurodegenerative diseases. Rev Neurosci 2015; 26:359-70. [PMID: 25741943 DOI: 10.1515/revneuro-2014-0085] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 01/08/2015] [Indexed: 11/15/2022]
Abstract
In neurons, enhanced protein kinase A (PKA) signaling elevates synaptic plasticity, promotes neuronal development, and increases dopamine synthesis. By contrast, a decline in PKA signaling contributes to the etiology of several brain degenerative diseases, including Alzheimer's disease and Parkinson's disease, suggesting that PKA predominantly plays a neuroprotective role. A-kinase anchoring proteins (AKAPs) are large multidomain scaffold proteins that target PKA and other signaling molecules to distinct subcellular sites to strategically localize PKA signaling at dendrites, dendritic spines, cytosol, and axons. PKA can be recruited to the outer mitochondrial membrane by associating with three different AKAPs to regulate mitochondrial dynamics, structure, mitochondrial respiration, trafficking, dendrite morphology, and neuronal survival. In this review, we survey the myriad of essential neuronal functions modulated by PKA but place a special emphasis on mitochondrially localized PKA. Finally, we offer an updated overview of how loss of PKA signaling contributes to the etiology of several brain degenerative diseases.
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Gupte RP, Kadunganattil S, Shepherd AJ, Merrill R, Planer W, Bruchas MR, Strack S, Mohapatra DP. Convergent phosphomodulation of the major neuronal dendritic potassium channel Kv4.2 by pituitary adenylate cyclase-activating polypeptide. Neuropharmacology 2015; 101:291-308. [PMID: 26456351 DOI: 10.1016/j.neuropharm.2015.10.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 09/29/2015] [Accepted: 10/03/2015] [Indexed: 12/30/2022]
Abstract
The endogenous neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) is secreted by both neuronal and non-neuronal cells in the brain and spinal cord, in response to pathological conditions such as stroke, seizures, chronic inflammatory and neuropathic pain. PACAP has been shown to exert various neuromodulatory and neuroprotective effects. However, direct influence of PACAP on the function of intrinsically excitable ion channels that are critical to both hyperexcitation as well as cell death, remain largely unexplored. The major dendritic K(+) channel Kv4.2 is a critical regulator of neuronal excitability, back-propagating action potentials in the dendrites, and modulation of synaptic inputs. We identified, cloned and characterized the downstream signaling originating from the activation of three PACAP receptor (PAC1) isoforms that are expressed in rodent hippocampal neurons that also exhibit abundant expression of Kv4.2 protein. Activation of PAC1 by PACAP leads to phosphorylation of Kv4.2 and downregulation of channel currents, which can be attenuated by inhibition of either PKA or ERK1/2 activity. Mechanistically, this dynamic downregulation of Kv4.2 function is a consequence of reduction in the density of surface channels, without any influence on the voltage-dependence of channel activation. Interestingly, PKA-induced effects on Kv4.2 were mediated by ERK1/2 phosphorylation of the channel at two critical residues, but not by direct channel phosphorylation by PKA, suggesting a convergent phosphomodulatory signaling cascade. Altogether, our findings suggest a novel GPCR-channel signaling crosstalk between PACAP/PAC1 and Kv4.2 channel in a manner that could lead to neuronal hyperexcitability.
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Affiliation(s)
- Raeesa P Gupte
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Suraj Kadunganattil
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Andrew J Shepherd
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Ronald Merrill
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - William Planer
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael R Bruchas
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Stefan Strack
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Durga P Mohapatra
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, IA 52242, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Castillo AF, Orlando U, Helfenberger KE, Poderoso C, Podesta EJ. The role of mitochondrial fusion and StAR phosphorylation in the regulation of StAR activity and steroidogenesis. Mol Cell Endocrinol 2015; 408:73-9. [PMID: 25540920 DOI: 10.1016/j.mce.2014.12.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 12/16/2022]
Abstract
The steroidogenic acute regulatory (StAR) protein regulates the rate-limiting step in steroidogenesis, i.e. the delivery of cholesterol from the outer (OMM) to the inner (IMM) mitochondrial membrane. StAR is a 37-kDa protein with an N-terminal mitochondrial targeting sequence that is cleaved off during mitochondrial import to yield 30-kDa intramitochondrial StAR. StAR acts exclusively on the OMM and its activity is proportional to how long it remains on the OMM. However, the precise fashion and the molecular mechanism in which StAR remains on the OMM have not been elucidated yet. In this work we will discuss the role of mitochondrial fusion and StAR phosphorylation by the extracellular signal-regulated kinases 1/2 (ERK1/2) as part of the mechanism that regulates StAR retention on the OMM and activity.
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Affiliation(s)
- Ana F Castillo
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ulises Orlando
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Katia E Helfenberger
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Cecilia Poderoso
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ernesto J Podesta
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina.
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Affiliation(s)
- Katherine Labbé
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616; , ,
| | - Andrew Murley
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616; , ,
| | - Jodi Nunnari
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616; , ,
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Lee I, Hüttemann M. Energy crisis: the role of oxidative phosphorylation in acute inflammation and sepsis. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:1579-86. [PMID: 24905734 PMCID: PMC4147665 DOI: 10.1016/j.bbadis.2014.05.031] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 04/17/2014] [Accepted: 05/27/2014] [Indexed: 12/13/2022]
Abstract
Mitochondrial dysfunction is increasingly recognized as an accomplice in most of the common human diseases including cancer, neurodegeneration, diabetes, ischemia/reperfusion injury as seen in myocardial infarction and stroke, and sepsis. Inflammatory conditions, both acute and chronic, have recently been shown to affect mitochondrial function. We here discuss the role of oxidative phosphorylation (OxPhos), focusing on acute inflammatory conditions, in particular sepsis and experimental sepsis models. We discuss mitochondrial alterations, specifically the suppression of oxidative metabolism and the role of mitochondrial reactive oxygen species in disease pathology. Several signaling pathways including metabolic, proliferative, and cytokine signaling affect mitochondrial function and appear to be important in inflammatory disease conditions. Cytochrome c oxidase (COX) and cytochrome c, the latter of which plays a central role in apoptosis in addition to mitochondrial respiration, serve as examples for the entire OxPhos system since they have been studied in more detail with respect to cell signaling. We propose a model in which inflammatory signaling leads to changes in the phosphorylation state of mitochondrial proteins, including Tyr304 phosphorylation of COX catalytic subunit I. This results in an inhibition of OxPhos, a reduction of the mitochondrial membrane potential, and consequently a lack of energy, which can cause organ failure and death as seen in septic patients.
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Affiliation(s)
- Icksoo Lee
- College of Medicine, Dankook University, Cheonan-si, Chungcheongnam-do 330-714, Republic of Korea
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201, USA; Cardiovascular Research Institute, Wayne State University, Detroit, MI 48201, USA; Department of Biochemistry and Molecular Biology, Wayne State University, Detroit, MI 48201, USA; Karmanos Cancer Institute, Detroit, MI 48201, USA.
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Martin M, Geudens I, Bruyr J, Potente M, Bleuart A, Lebrun M, Simonis N, Deroanne C, Twizere JC, Soubeyran P, Peixoto P, Mottet D, Janssens V, Hofmann WK, Claes F, Carmeliet P, Kettmann R, Gerhardt H, Dequiedt F. PP2A regulatory subunit Bα controls endothelial contractility and vessel lumen integrity via regulation of HDAC7. EMBO J 2013; 32:2491-503. [PMID: 23955003 DOI: 10.1038/emboj.2013.187] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 07/19/2013] [Indexed: 01/04/2023] Open
Abstract
To supply tissues with nutrients and oxygen, the cardiovascular system forms a seamless, hierarchically branched, network of lumenized tubes. Here, we show that maintenance of patent vessel lumens requires the Bα regulatory subunit of protein phosphatase 2A (PP2A). Deficiency of Bα in zebrafish precludes vascular lumen stabilization resulting in perfusion defects. Similarly, inactivation of PP2A-Bα in cultured ECs induces tubulogenesis failure due to alteration of cytoskeleton dynamics, actomyosin contractility and maturation of cell-extracellular matrix (ECM) contacts. Mechanistically, we show that PP2A-Bα controls the activity of HDAC7, an essential transcriptional regulator of vascular stability. In the absence of PP2A-Bα, transcriptional repression by HDAC7 is abrogated leading to enhanced expression of the cytoskeleton adaptor protein ArgBP2. ArgBP2 hyperactivates RhoA causing inadequate rearrangements of the EC actomyosin cytoskeleton. This study unravels the first specific role for a PP2A holoenzyme in development: the PP2A-Bα/HDAC7/ArgBP2 axis maintains vascular lumens by balancing endothelial cytoskeletal dynamics and cell-matrix adhesion.
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Affiliation(s)
- Maud Martin
- Laboratory of Protein Signaling and Interactions, Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, Sart-Tilman, Belgium
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Slupe AM, Merrill RA, Flippo KH, Lobas MA, Houtman JCD, Strack S. A calcineurin docking motif (LXVP) in dynamin-related protein 1 contributes to mitochondrial fragmentation and ischemic neuronal injury. J Biol Chem 2013; 288:12353-65. [PMID: 23486469 PMCID: PMC3636919 DOI: 10.1074/jbc.m113.459677] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fission and fusion events dynamically control the shape and function of mitochondria. The activity of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1) is finely tuned by several post-translational modifications. Phosphorylation of Ser-656 by cAMP-dependent protein kinase (PKA) inhibits Drp1, whereas dephosphorylation by a mitochondrial protein phosphatase 2A isoform and the calcium-calmodulin-dependent phosphatase calcineurin (CaN) activates Drp1. Here, we identify a conserved CaN docking site on Drp1, an LXVP motif, which mediates the interaction between the phosphatase and mechanoenzyme. We mutated the LXVP motif in Drp1 to either increase or decrease similarity to the prototypical LXVP motif in the transcription factor NFAT, and assessed stability of the mutant Drp1-CaN complexes by affinity precipitation and isothermal titration calorimetry. Furthermore, we quantified effects of LXVP mutations on Drp1 dephosphorylation kinetics in vitro and in intact cells. With tools for bidirectional control of the CaN-Drp1 signaling axis in hand, we demonstrate that the Drp1 LXVP motif shapes mitochondria in neuronal and non-neuronal cells, and that CaN-mediated Drp1 dephosphorylation promotes neuronal death following oxygen-glucose deprivation. These results point to the CaN-Drp1 complex as a potential target for neuroprotective therapy of ischemic stroke.
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Affiliation(s)
- Andrew M Slupe
- Department of Pharmacology, University of Iowa, Iowa City, Iowa 52242, USA
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Galloway CA, Lee H, Yoon Y. Mitochondrial morphology-emerging role in bioenergetics. Free Radic Biol Med 2012; 53:2218-28. [PMID: 23032099 PMCID: PMC3594133 DOI: 10.1016/j.freeradbiomed.2012.09.035] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/20/2012] [Accepted: 09/22/2012] [Indexed: 11/25/2022]
Abstract
Dynamic change in mitochondrial shape is a cellular process mediated mainly by fission and fusion of mitochondria. Studies have shown that mitochondrial fission and fusion are directly and indirectly associated with mitochondrial maintenance, bioenergetic demand, and cell death. Changes in mitochondrial morphology are frequently observed in response to changes in the surrounding cellular milieu, such as metabolic flux, that influence cellular bioenergetics. Connections between morphological regulation and the bioenergetic status of mitochondria are emerging as reciprocally responsive processes, though the nature of the signaling remains to be defined. Given the pivotal role mitochondria play in cellular fate, tight regulation of fission and fusion is therefore critical to preserving normal cellular physiology. Here we describe recent advancements in the understanding of the mechanisms governing mitochondrial morphology and their emerging role in mitochondrial bioenergetics.
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Affiliation(s)
- Chad A Galloway
- Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Hakjoo Lee
- Department of Physiology, Georgia Health Sciences University, Augusta, GA 30912, USA
| | - Yisang Yoon
- Department of Physiology, Georgia Health Sciences University, Augusta, GA 30912, USA.
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