1
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Castellón JO, Ofori S, Burton NR, Julio AR, Turmon AC, Armenta E, Sandoval C, Boatner LM, Takayoshi EE, Faragalla M, Taylor C, Zhou AL, Tran K, Shek J, Yan T, Desai HS, Fregoso OI, Damoiseaux R, Backus KM. Chemoproteomics Identifies State-Dependent and Proteoform-Selective Caspase-2 Inhibitors. J Am Chem Soc 2024; 146:14972-14988. [PMID: 38787738 DOI: 10.1021/jacs.3c12240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
Caspases are a highly conserved family of cysteine-aspartyl proteases known for their essential roles in regulating apoptosis, inflammation, cell differentiation, and proliferation. Complementary to genetic approaches, small-molecule probes have emerged as useful tools for modulating caspase activity. However, due to the high sequence and structure homology of all 12 human caspases, achieving selectivity remains a central challenge for caspase-directed small-molecule inhibitor development efforts. Here, using mass spectrometry-based chemoproteomics, we first identify a highly reactive noncatalytic cysteine that is unique to caspase-2. By combining both gel-based activity-based protein profiling (ABPP) and a tobacco etch virus (TEV) protease activation assay, we then identify covalent lead compounds that react preferentially with this cysteine and afford a complete blockade of caspase-2 activity. Inhibitory activity is restricted to the zymogen or precursor form of monomeric caspase-2. Focused analogue synthesis combined with chemoproteomic target engagement analysis in cellular lysates and in cells yielded both pan-caspase-reactive molecules and caspase-2 selective lead compounds together with a structurally matched inactive control. Application of this focused set of tool compounds to stratify the functions of the zymogen and partially processed (p32) forms of caspase-2 provide evidence to support that caspase-2-mediated response to DNA damage is largely driven by the partially processed p32 form of the enzyme. More broadly, our study highlights future opportunities for the development of proteoform-selective caspase inhibitors that target nonconserved and noncatalytic cysteine residues.
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Affiliation(s)
- José O Castellón
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
| | - Samuel Ofori
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
| | - Nikolas R Burton
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Ashley R Julio
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Alexandra C Turmon
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Ernest Armenta
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Carina Sandoval
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095, United States
| | - Lisa M Boatner
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Evan E Takayoshi
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Marina Faragalla
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Cameron Taylor
- California NanoSystems Institute (CNSI), UCLA, Los Angeles, California 90095, United States
| | - Ann L Zhou
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Ky Tran
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Jeremy Shek
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Tianyang Yan
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Heta S Desai
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
| | - Oliver I Fregoso
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095, United States
| | - Robert Damoiseaux
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, California 90095, United States
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, UCLA, Los Angeles, California 90095, United States
- California NanoSystems Institute (CNSI), UCLA, Los Angeles, California 90095, United States
- Department of Molecular and Medical Pharmacology, UCLA, Los Angeles, California 90095, United States
- Department of Bioengineering, Samueli School of Engineering, UCLA, Los Angeles, California 90095, United States
| | - Keriann M Backus
- Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
- DOE Institute for Genomics and Proteomics, UCLA, Los Angeles, California 90095, United States
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, California 90095, United States
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, UCLA, Los Angeles, California 90095, United States
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2
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Svandova E, Vesela B, Janeckova E, Chai Y, Matalova E. Exploring caspase functions in mouse models. Apoptosis 2024:10.1007/s10495-024-01976-z. [PMID: 38824481 DOI: 10.1007/s10495-024-01976-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2024] [Indexed: 06/03/2024]
Abstract
Caspases are enzymes with protease activity. Despite being known for more than three decades, caspase investigation still yields surprising and fascinating information. Initially associated with cell death and inflammation, their functions have gradually been revealed to extend beyond, targeting pathways such as cell proliferation, migration, and differentiation. These processes are also associated with disease mechanisms, positioning caspases as potential targets for numerous pathologies including inflammatory, neurological, metabolic, or oncological conditions. While in vitro studies play a crucial role in elucidating molecular pathways, they lack the context of the body's complexity. Therefore, laboratory animals are an indispensable part of successfully understanding and applying caspase networks. This paper aims to summarize and discuss recent knowledge, understanding, and challenges in caspase knock-out mice.
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Affiliation(s)
- Eva Svandova
- Laboratory of Odontogenesis and Osteogenesis, Institute of Animal Physiology and Genetic, Brno, Czech Republic.
| | - Barbora Vesela
- Laboratory of Odontogenesis and Osteogenesis, Institute of Animal Physiology and Genetic, Brno, Czech Republic
| | - Eva Janeckova
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, USA
| | - Yang Chai
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, USA
| | - Eva Matalova
- Laboratory of Odontogenesis and Osteogenesis, Institute of Animal Physiology and Genetic, Brno, Czech Republic
- Department of Physiology, University of Veterinary Sciences, Brno, Czech Republic
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3
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Cuellar ME, Yang M, Karavadhi S, Zhang YQ, Zhu H, Sun H, Shen M, Hall MD, Patnaik S, Ashe KH, Walters MA, Pockes S. An electrophilic fragment screening for the development of small molecules targeting caspase-2. Eur J Med Chem 2023; 259:115632. [PMID: 37453329 PMCID: PMC10529632 DOI: 10.1016/j.ejmech.2023.115632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/04/2023] [Accepted: 07/09/2023] [Indexed: 07/18/2023]
Abstract
Recent Alzheimer's research has shown increasing interest in the caspase-2 (Casp2) enzyme. However, the available Casp2 inhibitors, which have been pentapeptides or peptidomimetics, face challenges for use as CNS drugs. In this study, we successfully screened a 1920-compound chloroacetamide-based, electrophilic fragment library from Enamine. Our two-point dose screen identified 64 Casp2 hits, which were further evaluated in a ten-point dose-response study to assess selectivity over Casp3. We discovered compounds with inhibition values in the single-digit micromolar and sub-micromolar range, as well as up to 32-fold selectivity for Casp2 over Casp3. Target engagement analysis confirmed the covalent-irreversible binding of the selected fragments to Cys320 at the active site of Casp2. Overall, our findings lay a strong foundation for the future development of small-molecule Casp2 inhibitors.
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Affiliation(s)
- Matthew E Cuellar
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN, 55414, USA
| | - Mu Yang
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN, 55414, USA
| | - Surendra Karavadhi
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Ya-Qin Zhang
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Hu Zhu
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Hongmao Sun
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Min Shen
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Matthew D Hall
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Samarjit Patnaik
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Karen H Ashe
- Department of Neurology, University of Minnesota, 2101 6th Street SE, Minneapolis, MN, 55455, USA
| | - Michael A Walters
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN, 55414, USA.
| | - Steffen Pockes
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN, 55414, USA; Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
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4
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Castellón JO, Ofori S, Armenta E, Burton N, Boatner LM, Takayoshi EE, Faragalla M, Zhou A, Tran K, Shek J, Yan T, Desai HS, Backus KM. Chemoproteomics identifies proteoform-selective caspase-2 inhibitors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.25.563785. [PMID: 37961563 PMCID: PMC10634807 DOI: 10.1101/2023.10.25.563785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Caspases are a highly conserved family of cysteine-aspartyl proteases known for their essential roles in regulating apoptosis, inflammation, cell differentiation, and proliferation. Complementary to genetic approaches, small-molecule probes have emerged as useful tools for modulating caspase activity. However, due to the high sequence and structure homology of all twelve human caspases, achieving selectivity remains a central challenge for caspase-directed small-molecule inhibitor development efforts. Here, using mass spectrometry-based chemoproteomics, we first identify a highly reactive non-catalytic cysteine that is unique to caspase-2. By combining both gel-based activity-based protein profiling (ABPP) and a tobacco etch virus (TEV) protease activation assay, we then identify covalent lead compounds that react preferentially with this cysteine and afford a complete blockade of caspase-2 activity. Inhibitory activity is restricted to the zymogen or precursor form of monomeric caspase-2. Focused analogue synthesis combined with chemoproteomic target engagement analysis in cellular lysates and in cells yielded both pan-caspase reactive molecules and caspase-2 selective lead compounds together with a structurally matched inactive control. Application of this focused set of tool compounds to stratify caspase contributions to initiation of intrinsic apoptosis, supports compensatory caspase-9 activity in the context of caspase-2 inactivation. More broadly, our study highlights future opportunities for the development of proteoform-selective caspase inhibitors that target non-conserved and non-catalytic cysteine residues.
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5
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Zamani N, Osgoei LT, Aliaghaei A, Zamani N, Hassanian-Moghaddam H. Chronic exposure to methadone induces activated microglia and astrocyte and cell death in the cerebellum of adult male rats. Metab Brain Dis 2023; 38:323-338. [PMID: 36287354 DOI: 10.1007/s11011-022-01108-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 10/13/2022] [Indexed: 02/03/2023]
Abstract
Methadone is a centrally-acting synthetic opioid analgesic widely used in the methadone maintenance therapy (MMT) programs throughout the world. Considering its neurotoxic effects particularly on the cerebellum, this study aims to address the behavioral and histological alterations in the cerebellar cortex associated with methadone administration. Twenty-four adult male albino rats were randomized into two groups of control and methadone treatment. Methadone was subcutaneously administered (2.5-10 mg/kg) once a day for two consecutive weeks. The functional and structural changes in the cerebellum were compared to the control group. Our data revealed that treating rats with methadone not only induced cerebellar atrophy, but also prompted the actuation of microgliosis, astrogliosis, and apoptotic biomarkers. We further demonstrated that treating rats with methadone increased complexity of astrocyte processes and decreased complexity of microglia processes. Our result showed that methadone impaired motor coordination and locomotor performance and neuromuscular activity. Additionally, relative gene expression of TNF-α, caspase-3 and RIPK3 increased significantly due to methadone. Our findings suggest that methadone administration has a neurodegenerative effect on the cerebellar cortex via dysregulation of microgliosis, astrogliosis, apoptosis, and neuro-inflammation.
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Affiliation(s)
- Naghmeh Zamani
- Department of Biology, Faculty of Biological Science, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Laya Takbiri Osgoei
- Department of Microbiology, Faculty of Biological Science, North Tehran Branch, Islamic Azad University, Tehran, Iran.
| | - Abbas Aliaghaei
- Hearing Disorders Research Center, Loghman-Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
- Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Nasim Zamani
- Department of Clinical Toxicology, Loghman-Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hossein Hassanian-Moghaddam
- Department of Clinical Toxicology, Loghman-Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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6
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Hlynialuk C, Kemper L, Leinonen-Wright K, Petersen RC, Ashe K, Smith B. Caspase-2 mRNA levels are not elevated in mild cognitive impairment, Alzheimer's disease, Huntington's disease, or Lewy Body dementia. PLoS One 2022; 17:e0274784. [PMID: 36129947 PMCID: PMC9491574 DOI: 10.1371/journal.pone.0274784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/05/2022] [Indexed: 11/28/2022] Open
Abstract
Caspase-2 is a member of the caspase family that exhibits both apoptotic and non-apoptotic properties, and has been shown to mediate synaptic deficits in models of several neurological conditions, including Alzheimer's disease (AD), Huntington's disease (HD), and Lewy Body dementia (LBD). Our lab previously reported that caspase-2 protein levels are elevated in these diseases, leading us to hypothesize that elevated caspase-2 protein levels are due to increased transcription of caspase-2 mRNA. There are two major isoforms of caspase-2 mRNA, caspase-2L and caspase-2S. We tested our hypothesis by measuring the levels of these mRNA isoforms normalized to levels of RPL13 mRNA, a reference gene that showed no disease-associated changes. Here, we report no increases in caspase-2L mRNA levels in any of the three diseases studied, AD (with mild cognitive impairment (MCI)), HD and LBD, disproving our hypothesis. Caspase-2S mRNA showed a non-significant downward trend in AD. We also analyzed expression levels of SNAP25 and βIII-tubulin mRNA. SNAP25 mRNA was significantly lower in AD and there were downward trends in MCI, LBD, and HD. βIII-tubulin mRNA expression remained unchanged between disease groups and controls. These findings indicate that factors besides transcriptional regulation cause increases in caspase-2 protein levels. The reduction of SNAP25 mRNA expression suggests that presynaptic dysfunction contributes to cognitive deficits in neurodegeneration.
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Affiliation(s)
- Chris Hlynialuk
- N. Bud Grossman Center for Memory Research and Care, University of Minnesota, Minneapolis, MN, United States of America
- Department of Neurology, University of Minnesota, Minneapolis, MN, United States of America
| | - Lisa Kemper
- N. Bud Grossman Center for Memory Research and Care, University of Minnesota, Minneapolis, MN, United States of America
- Department of Neurology, University of Minnesota, Minneapolis, MN, United States of America
| | - Kailee Leinonen-Wright
- N. Bud Grossman Center for Memory Research and Care, University of Minnesota, Minneapolis, MN, United States of America
- Department of Neurology, University of Minnesota, Minneapolis, MN, United States of America
| | - Ronald C. Petersen
- Department of Neurology, Mayo Clinic, Rochester, MN, United States of America
| | - Karen Ashe
- N. Bud Grossman Center for Memory Research and Care, University of Minnesota, Minneapolis, MN, United States of America
- Department of Neurology, University of Minnesota, Minneapolis, MN, United States of America
- Minneapolis VA Medical Center, Minneapolis, MN, United States of America
| | - Benjamin Smith
- N. Bud Grossman Center for Memory Research and Care, University of Minnesota, Minneapolis, MN, United States of America
- Department of Neurology, University of Minnesota, Minneapolis, MN, United States of America
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7
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Heib M, Weiß J, Saggau C, Hoyer J, Fuchslocher Chico J, Voigt S, Adam D. Ars moriendi: Proteases as sculptors of cellular suicide. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119191. [PMID: 34973300 DOI: 10.1016/j.bbamcr.2021.119191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
The Ars moriendi, which translates to "The Art of Dying," encompasses two Latin texts that gave advice on how to die well and without fear according to the Christian precepts of the late Middle Ages. Given that ten to hundred billion cells die in our bodies every day, it is obvious that the concept of a well and orderly ("regulated") death is also paramount at the cellular level. In apoptosis, as the most well-studied form of regulated cell death, proteases of the caspase family are the central mediators. However, caspases are not the only proteases that act as sculptors of cellular suicide, and therefore, we here provide an overview of the impact of proteases in apoptosis and other forms of regulated cell death.
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Affiliation(s)
- Michelle Heib
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Jonas Weiß
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Carina Saggau
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Justus Hoyer
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | | | - Susann Voigt
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Dieter Adam
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany.
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Therapeutic potential of Nlrp1 inflammasome, Caspase-1, or Caspase-6 against Alzheimer disease cognitive impairment. Cell Death Differ 2022; 29:657-669. [PMID: 34625662 PMCID: PMC8901623 DOI: 10.1038/s41418-021-00881-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/08/2022] Open
Abstract
The sequential activation of Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing protein 1 (Nlrp1) inflammasome, Caspase-1 (Casp1), and Caspase-6 (Casp6) is implicated in primary human neuron cultures and Alzheimer Disease (AD) neurodegeneration. To validate the Nlrp1-Casp1-Casp6 pathway in vivo, the APPSwedish/Indiana J20 AD transgenic mouse model was generated on either a Nlrp1, Casp1 or Casp6 null genetic background and mice were studied at 4-5 months of age. Episodic memory deficits assessed with novel object recognition were normalized by genetic ablation of Nlrp1, Casp1, or Casp6 in J20 mice. Spatial learning deficits, assessed with the Barnes Maze, were normalized in genetically ablated J20, whereas memory recall was normalized in J20/Casp1-/- and J20/Casp6-/-, and improved in J20/Nlrp1-/- mice. Hippocampal CA1 dendritic spine density of the mushroom subtype was reduced in J20, and normalized in genetically ablated J20 mice. Reduced J20 hippocampal dentate gyrus and CA3 synaptophysin levels were normalized in genetically ablated J20. Increased Iba1+-microglia in the hippocampus and cortex of J20 brains were normalized by Casp1 and Casp6 ablation and reduced by Nlrp1 ablation. Increased pro-inflammatory cytokines, TNF-α and CXCL1, in the J20 hippocampus were normalized by Nlrp1 or Casp1 genetic ablation. CXCL1 was also normalized by Casp6 genetic ablation. IFN-γ was increased and total amyloid β peptide was decreased in genetically ablated Nlrp1, Casp1 or Casp6 J20 hippocampi. We conclude that Nlrp1, Casp1, or Casp6 are implicated in AD-related cognitive impairment, inflammation, and amyloidogenesis. These results indicate that Nlrp1, Casp1, and Casp6 represent rational therapeutic targets against cognitive impairment and inflammation in AD.
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Over Fifty Years of Life, Death, and Cannibalism: A Historical Recollection of Apoptosis and Autophagy. Int J Mol Sci 2021; 22:ijms222212466. [PMID: 34830349 PMCID: PMC8618802 DOI: 10.3390/ijms222212466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 01/18/2023] Open
Abstract
Research in biomedical sciences has changed dramatically over the past fifty years. There is no doubt that the discovery of apoptosis and autophagy as two highly synchronized and regulated mechanisms in cellular homeostasis are among the most important discoveries in these decades. Along with the advancement in molecular biology, identifying the genetic players in apoptosis and autophagy has shed light on our understanding of their function in physiological and pathological conditions. In this review, we first describe the history of key discoveries in apoptosis with a molecular insight and continue with apoptosis pathways and their regulation. We touch upon the role of apoptosis in human health and its malfunction in several diseases. We discuss the path to the morphological and molecular discovery of autophagy. Moreover, we dive deep into the precise regulation of autophagy and recent findings from basic research to clinical applications of autophagy modulation in human health and illnesses and the available therapies for many diseases caused by impaired autophagy. We conclude with the exciting crosstalk between apoptosis and autophagy, from the early discoveries to recent findings.
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10
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SRSF9 Regulates Cassette Exon Splicing of Caspase-2 by Interacting with Its Downstream Exon. Cells 2021; 10:cells10030679. [PMID: 33808656 PMCID: PMC8003524 DOI: 10.3390/cells10030679] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/01/2021] [Accepted: 03/16/2021] [Indexed: 11/16/2022] Open
Abstract
Alternative splicing (AS) is an important posttranscriptional regulatory process. Damaged or unnecessary cells need to be removed though apoptosis to maintain physiological processes. Caspase-2 pre-mRNA produces pro-apoptotic long mRNA and anti-apoptotic short mRNA isoforms through AS. How AS of Caspase-2 is regulated remains unclear. In the present study, we identified a novel regulatory protein SRSF9 for AS of Caspase-2 cassette exon 9. Knock-down (KD) of SRSF9 increased inclusion of cassette exon and on the other hand, overexpression of SRSF9 decreased inclusion of this exon. Deletion mutagenesis demonstrated that exon 9, parts of intron 9, exon 8 and exon 10 were not required for the role of SRSF9 in Caspase-2 AS. However, deletion and substitution mutation analysis revealed that AGGAG sequence located at exon 10 provided functional target for SRSF9. In addition, RNA-pulldown mediated immunoblotting analysis showed that SRSF9 interacted with this sequence. Gene ontology analysis of RNA-seq from SRSF9 KD cells demonstrates that SRSF9 could regulate AS of a subset of apoptosis related genes. Collectively, our results reveal a basis for regulation of Caspase-2 AS.
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11
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Vigneswara V, Ahmed Z. The Role of Caspase-2 in Regulating Cell Fate. Cells 2020; 9:cells9051259. [PMID: 32438737 PMCID: PMC7290664 DOI: 10.3390/cells9051259] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022] Open
Abstract
Caspase-2 is the most evolutionarily conserved member of the mammalian caspase family and has been implicated in both apoptotic and non-apoptotic signaling pathways, including tumor suppression, cell cycle regulation, and DNA repair. A myriad of signaling molecules is associated with the tight regulation of caspase-2 to mediate multiple cellular processes far beyond apoptotic cell death. This review provides a comprehensive overview of the literature pertaining to possible sophisticated molecular mechanisms underlying the multifaceted process of caspase-2 activation and to highlight its interplay between factors that promote or suppress apoptosis in a complicated regulatory network that determines the fate of a cell from its birth and throughout its life.
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12
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Abstract
Alternative splicing of precursor mRNA is a key mediator of gene expression regulation leading to greater diversity of the proteome in complex organisms. Systematic sequencing of the human genome and transcriptome has led to our understanding of how alternative splicing of critical genes leads to multiple pathological conditions such as cancer. For many years, proteases were known only for their roles as proteolytic enzymes, acting to regulate/process proteins associated with diverse cellular functions. However, the differential expression and altered function of various protease isoforms, such as (i) anti-apoptotic activities, (ii) mediating intercellular adhesion, and (iii) modifying the extracellular matrix, are evidence of their specific contribution towards shaping the tumor microenvironment. Revealing the alternative splicing of protease genes and characterization of their protein products/isoforms with distinct and opposing functions creates a platform to understand how protease isoforms contribute to specific cancer hallmarks. Here, in this review, we address cancer-specific isoforms produced by the alternative splicing of proteases and their distinctive roles in the tumor microenvironment.
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Affiliation(s)
- Chamikara Liyanage
- School of Biomedical Sciences, Faculty of Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
- Australian Prostate Cancer Research Centre-Queensland (APCRC-Q), Translational Research Institute, Queensland University of Technology, Brisbane, Australia
| | - Achala Fernando
- School of Biomedical Sciences, Faculty of Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
- Australian Prostate Cancer Research Centre-Queensland (APCRC-Q), Translational Research Institute, Queensland University of Technology, Brisbane, Australia
| | - Jyotsna Batra
- School of Biomedical Sciences, Faculty of Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
- Australian Prostate Cancer Research Centre-Queensland (APCRC-Q), Translational Research Institute, Queensland University of Technology, Brisbane, Australia.
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13
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Xu ZX, Tan JW, Xu H, Hill CJ, Ostrovskaya O, Martemyanov KA, Xu B. Caspase-2 promotes AMPA receptor internalization and cognitive flexibility via mTORC2-AKT-GSK3β signaling. Nat Commun 2019; 10:3622. [PMID: 31399584 PMCID: PMC6689033 DOI: 10.1038/s41467-019-11575-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 07/23/2019] [Indexed: 01/22/2023] Open
Abstract
Caspase-2 is the most evolutionarily conserved member in the caspase family of proteases and is constitutively expressed in most cell types including neurons; however, its physiological function remains largely unknown. Here we report that caspase-2 plays a critical role in synaptic plasticity and cognitive flexibility. We found that caspase-2 deficiency led to deficits in dendritic spine pruning, internalization of AMPA receptors and long-term depression. Our results indicate that caspase-2 degrades Rictor, a key mTOR complex 2 (mTORC2) component, to inhibit Akt activation, which leads to enhancement of the GSK3β activity and thereby long-term depression. Furthermore, we found that mice lacking caspase-2 displayed elevated levels of anxiety, impairment in reversal water maze learning, and little memory loss over time. These results not only uncover a caspase-2-mTORC2-Akt-GSK3β signaling pathway, but also suggest that caspase-2 is important for memory erasing and normal behaviors by regulating synaptic number and transmission.
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Affiliation(s)
- Zhi-Xiang Xu
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Ji-Wei Tan
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Haifei Xu
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Cassandra J Hill
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Olga Ostrovskaya
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Baoji Xu
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, 33458, USA.
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14
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Inhibition of Caspase-2 Translation by the mRNA Binding Protein HuR: A Novel Path of Therapy Resistance in Colon Carcinoma Cells? Cells 2019; 8:cells8080797. [PMID: 31366165 PMCID: PMC6721497 DOI: 10.3390/cells8080797] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 12/28/2022] Open
Abstract
An increased expression and cytoplasmic abundance of the ubiquitous RNA binding protein human antigen R (HuR) is critically implicated in the dysregulated control of post- transcriptional gene expression during colorectal cancer development and is frequently associated with a high grade of malignancy and therapy resistance. Regardless of the fact that HuR elicits a broad cell survival program by increasing the stability of mRNAs coding for prominent anti-apoptotic factors, recent data suggest that HuR is critically involved in the regulation of translation, particularly, in the internal ribosome entry site (IRES) controlled translation of cell death regulatory proteins. Accordingly, data from human colon carcinoma cells revealed that HuR maintains constitutively reduced protein and activity levels of caspase-2 through negative interference with IRES-mediated translation. This review covers recent advances in the understanding of mechanisms underlying HuR's modulatory activity on IRES-triggered translation. With respect to the unique regulatory features of caspase-2 and its multiple roles (e.g., in DNA-damage-induced apoptosis, cell cycle regulation and maintenance of genomic stability), the pathophysiological consequences of negative caspase-2 regulation by HuR and its impact on therapy resistance of colorectal cancers will be discussed in detail. The negative HuR-caspase-2 axis may offer a novel target for tumor sensitizing therapies.
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15
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Profile of Junying Yuan. Proc Natl Acad Sci U S A 2019; 116:11564-11566. [DOI: 10.1073/pnas.1906915116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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16
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Potent and selective caspase-2 inhibitor prevents MDM-2 cleavage in reversine-treated colon cancer cells. Cell Death Differ 2019; 26:2695-2709. [PMID: 30976094 DOI: 10.1038/s41418-019-0329-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/17/2019] [Accepted: 03/25/2019] [Indexed: 01/02/2023] Open
Abstract
Most caspases can be positioned unambiguously within the regulated cell death networks of apoptosis and pyroptosis, but the role of caspase-2, a highly conserved protease within the family, remains enigmatic. This is mainly due to lack of selective chemical and biochemical tools for the investigation of this protease. In this study, we used our hybrid combinatorial substrate library (HyCoSuL) approach to broadly profile caspase-2 substrate specificity using peptide scanning libraries. This screen uncovered previously unknown caspase-2 peptidyl substrate preferences, which were further used to develop caspase-2 selective fluorogenic substrates and covalent, irreversible AOMK inhibitors. Finally, we used the champion inhibitor (NH-23-C2) in reversine-treated HCT-116 colon cancer cells to selectively block caspase-2 activity and caspase-2-mediated MDM-2 cleavage. In addition, we showed that NH-23-C2 does not block caspase-3 or caspase-8, which makes it a powerful chemical tool to dissect the true role of caspase-2 in various biological setups.
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17
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Regulating Apoptosis by Degradation: The N-End Rule-Mediated Regulation of Apoptotic Proteolytic Fragments in Mammalian Cells. Int J Mol Sci 2018; 19:ijms19113414. [PMID: 30384441 PMCID: PMC6274719 DOI: 10.3390/ijms19113414] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 10/24/2018] [Accepted: 10/27/2018] [Indexed: 12/13/2022] Open
Abstract
A pivotal hallmark of some cancer cells is the evasion of apoptotic cell death. Importantly, the initiation of apoptosis often results in the activation of caspases, which, in turn, culminates in the generation of proteolytically-activated protein fragments with potentially new or altered roles. Recent investigations have revealed that the activity of a significant number of the protease-generated, activated, pro-apoptotic protein fragments can be curbed via their selective degradation by the N-end rule degradation pathways. Of note, previous work revealed that several proteolytically-generated, pro-apoptotic fragments are unstable in cells, as their destabilizing N-termini target them for proteasomal degradation via the N-end rule degradation pathways. Remarkably, previous studies also showed that the proteolytically-generated anti-apoptotic Lyn kinase protein fragment is targeted for degradation by the UBR1/UBR2 E3 ubiquitin ligases of the N-end rule pathway in chronic myeloid leukemia cells. Crucially, the degradation of cleaved fragment of Lyn by the N-end rule counters imatinib resistance in these cells, implicating a possible linkage between the N-end rule degradation pathway and imatinib resistance. Herein, we highlight recent studies on the role of the N-end rule proteolytic pathways in regulating apoptosis in mammalian cells, and also discuss some possible future directions with respect to apoptotic proteolysis signaling.
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18
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Egorshina AY, Zamaraev AV, Lavrik IN, Zhivotovsky BD, Kopeina GS. Caspase-2 as an Oncosupressor and Metabolism Regulator: What Life Will Bring over the Long Run? Mol Biol 2018. [DOI: 10.1134/s0026893318050060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Robeson AC, Lindblom KR, Wojton J, Kornbluth S, Matsuura K. Dimer-specific immunoprecipitation of active caspase-2 identifies TRAF proteins as novel activators. EMBO J 2018; 37:e97072. [PMID: 29875129 PMCID: PMC6043850 DOI: 10.15252/embj.201797072] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 04/30/2018] [Accepted: 05/07/2018] [Indexed: 12/13/2022] Open
Abstract
Caspase-2 has been shown to initiate apoptotic cell death in response to specific intracellular stressors such as DNA damage. However, the molecular mechanisms immediately upstream of its activation are still poorly understood. We combined a caspase-2 bimolecular fluorescence complementation (BiFC) system with fluorophore-specific immunoprecipitation to isolate and study the active caspase-2 dimer and its interactome. Using this technique, we found that tumor necrosis factor receptor-associated factor 2 (TRAF2), as well as TRAF1 and 3, directly binds to the active caspase-2 dimer. TRAF2 in particular is necessary for caspase-2 activation in response to apoptotic cell death stimuli. Furthermore, we found that dimerized caspase-2 is ubiquitylated in a TRAF2-dependent manner at K15, K152, and K153, which in turn stabilizes the active caspase-2 dimer complex, promotes its association with an insoluble cellular fraction, and enhances its activity to fully commit the cell to apoptosis. Together, these data indicate that TRAF2 positively regulates caspase-2 activation and consequent cell death by driving its activation through dimer-stabilizing ubiquitylation.
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Affiliation(s)
- Alexander C Robeson
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Kelly R Lindblom
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Jeffrey Wojton
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Sally Kornbluth
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Kenkyo Matsuura
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
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20
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Urbanski L, Leclair N, Anczuków O. Alternative-splicing defects in cancer: Splicing regulators and their downstream targets, guiding the way to novel cancer therapeutics. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9:e1476. [PMID: 29693319 PMCID: PMC6002934 DOI: 10.1002/wrna.1476] [Citation(s) in RCA: 205] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/14/2022]
Abstract
Defects in alternative splicing are frequently found in human tumors and result either from mutations in splicing-regulatory elements of specific cancer genes or from changes in the regulatory splicing machinery. RNA splicing regulators have emerged as a new class of oncoproteins and tumor suppressors, and contribute to disease progression by modulating RNA isoforms involved in the hallmark cancer pathways. Thus, dysregulation of alternative RNA splicing is fundamental to cancer and provides a potentially rich source of novel therapeutic targets. Here, we review the alterations in splicing regulatory factors detected in human tumors, as well as the resulting alternatively spliced isoforms that impact cancer hallmarks, and discuss how they contribute to disease pathogenesis. RNA splicing is a highly regulated process and, as such, the regulators are themselves tightly regulated. Differential transcriptional and posttranscriptional regulation of splicing factors modulates their levels and activities in tumor cells. Furthermore, the composition of the tumor microenvironment can also influence which isoforms are expressed in a given cell type and impact drug responses. Finally, we summarize current efforts in targeting alternative splicing, including global splicing inhibition using small molecules blocking the spliceosome or splicing-factor-modifying enzymes, as well as splice-switching RNA-based therapeutics to modulate cancer-specific splicing isoforms. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing.
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21
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Holcomb JD, Graham S, Calof AL. Neuronal Homeostasis in Mammalian Olfactory Epithelium: A Review. ACTA ACUST UNITED AC 2018. [DOI: 10.2500/105065896781794879] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The neuronal lineage of the olfactory epithelium (OE) is a cell lineage that includes the neuronal stem cell and its progeny (ultimately the mature olfactory receptor neuron [ORN]). Recent studies, including further characterization of the neuronal lineage of the OE, and of factors that influence proliferation, survival, and death of cells of this lineage, have contributed significantly to understanding of neuronal homeostasis, i.e., normal maintenance of neuronal number, in mammalian OE. Our recent studies indicate that in adult mice, all cell types of the neuronal lineage of the OE—neuronal precursors, immature ORNs and mature ORNs—undergo constitutive death, i.e., a normal, basal level of cell death, that is characteristic of programmed cell death or apoptosis. To some extent, constitutive cell death in this lineage may reflect random environmental insults; however, this may also be the result of an ongoing developmental program that acts to control both numbers and phenotypic organization of olfactory neurons. Although a variety of extrinsic and intrinsic factors are likely to contribute to cell death in the neuronal lineage of the OE, most have not been thoroughly studied. Detailed analysis of one of these factors, effects of target deprivation, suggests that survival of individual cell types of the neuronal lineage of the OE may be differentially regulated with mature ORNs, but not immature ORNs or neuronal precursors, dependent upon the olfactory bulb for their survival. Factors normally provided to cells of the ORN lineage, as in other neuronal systems, are likely to promote survival by inhibiting an endogenous genetic program of cell death. Whether candidate polypeptide growth factors, e.g., the neurotrophins, or other pharmacological inhibitors of apoptosis will eventually play a role in the treatment of specific anosmias remains to be determined.
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Affiliation(s)
- J. David Holcomb
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Scott Graham
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Anne L. Calof
- Department of Anatomy and Neurobiology and the Developmental Biology Center, University of California at Irvine, Irvine, California
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22
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Zhdanov DD, Gladilina YA, Grishin DV, Pokrovsky VS, Pokrovskaya MV, Aleksandrova SS, Sokolov NN. Apoptotic Endonuclease EndoG Induces Alternative Splicing of Telomerase TERT Catalytic Subunit, Caspase-2, DNase I, and BCL-x in Human, Murine, and Rat CD4+ T Lymphocytes. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2018. [DOI: 10.1134/s1068162018010181] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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23
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Splicing dysfunction and disease: The case of granulopoiesis. Semin Cell Dev Biol 2018; 75:23-39. [DOI: 10.1016/j.semcdb.2017.08.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/28/2017] [Accepted: 08/28/2017] [Indexed: 12/20/2022]
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24
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Richards AL, Watza D, Findley A, Alazizi A, Wen X, Pai AA, Pique-Regi R, Luca F. Environmental perturbations lead to extensive directional shifts in RNA processing. PLoS Genet 2017; 13:e1006995. [PMID: 29023442 PMCID: PMC5667937 DOI: 10.1371/journal.pgen.1006995] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 11/02/2017] [Accepted: 08/21/2017] [Indexed: 02/06/2023] Open
Abstract
Environmental perturbations have large effects on both organismal and cellular traits, including gene expression, but the extent to which the environment affects RNA processing remains largely uncharacterized. Recent studies have identified a large number of genetic variants associated with variation in RNA processing that also have an important role in complex traits; yet we do not know in which contexts the different underlying isoforms are used. Here, we comprehensively characterized changes in RNA processing events across 89 environments in five human cell types and identified 15,300 event shifts (FDR = 15%) comprised of eight event types in over 4,000 genes. Many of these changes occur consistently in the same direction across conditions, indicative of global regulation by trans factors. Accordingly, we demonstrate that environmental modulation of splicing factor binding predicts shifts in intron retention, and that binding of transcription factors predicts shifts in alternative first exon (AFE) usage in response to specific treatments. We validated the mechanism hypothesized for AFE in two independent datasets. Using ATAC-seq, we found altered binding of 64 factors in response to selenium at sites of AFE shift, including ELF2 and other factors in the ETS family. We also performed AFE QTL mapping in 373 individuals and found an enrichment for SNPs predicted to disrupt binding of the ELF2 factor. Together, these results demonstrate that RNA processing is dramatically changed in response to environmental perturbations through specific mechanisms regulated by trans factors.
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Affiliation(s)
- Allison L. Richards
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- * E-mail: (ALR); (AAP); (RPR); (FL)
| | - Donovan Watza
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
| | - Anthony Findley
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
| | - Adnan Alazizi
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
| | - Xiaoquan Wen
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Athma A. Pai
- RNA Therapeutics Institute, University of Massachusetts, Worcester, Massachusetts, United States of America
- * E-mail: (ALR); (AAP); (RPR); (FL)
| | - Roger Pique-Regi
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan, United States of America
- * E-mail: (ALR); (AAP); (RPR); (FL)
| | - Francesca Luca
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan, United States of America
- * E-mail: (ALR); (AAP); (RPR); (FL)
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25
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Shamsi A, Bano B. Journey of cystatins from being mere thiol protease inhibitors to at heart of many pathological conditions. Int J Biol Macromol 2017; 102:674-693. [PMID: 28445699 PMCID: PMC7112400 DOI: 10.1016/j.ijbiomac.2017.04.071] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 02/04/2023]
Abstract
Cystatins are thiol proteinase inhibitors (TPI), present ubiquitously in animals, plants and micro-organisms. These are not merely inhibitors rather they are at heart of many pathological conditions ranging from diabetes to renal failure. These are essential for maintenance of protein balance of the cell; once this balance gets disturbed, it may lead to cell death. Thus, cystatins cannot be merely regarded as TPI's as these have been found to play a pivotal role in tumorigenesis and neurodegenerative diseases. Many studies have reported the variation in cystatin level in incidences of different types of cancer; highlighting an important role played by these inhibitors in cancer development and progression. Cystatin C is increasingly replacing creatinine as a biomarker of glomerular filtration rate (GFR) thereby highlighting the importance of this important inhibitor. Some recent studies have also reported the interaction pattern of various anti-cancer drugs with cystatins in a bid to find how these drugs affect this important inhibitors and whether these drugs have any side effect on cystatins. Thus, in this growing disease era it can be said that cystatins are no more just inhibitors blocking the activity of thiol proteases rather they play a pivotal role in variety of pathological conditions.
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Affiliation(s)
- Anas Shamsi
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, India
| | - Bilqees Bano
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, India.
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26
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Dlamini Z, Mokoena F, Hull R. Abnormalities in alternative splicing in diabetes: therapeutic targets. J Mol Endocrinol 2017; 59:R93-R107. [PMID: 28716821 DOI: 10.1530/jme-17-0049] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 05/30/2017] [Indexed: 12/19/2022]
Abstract
Diabetes mellitus (DM) is a non-communicable, metabolic disorder that affects 416 million individuals worldwide. Type 2 diabetes contributes to a vast 85-90% of the diabetes incidences while 10-15% of patients suffer from type 1 diabetes. These two predominant forms of DM cause a significant loss of functional pancreatic β-cell mass causing different degrees of insulin deficiency, most likely, due to increased β-cell apoptosis. Treatment options involve the use of insulin sensitisers, α-glucosidase inhibitors, and β-cell secretagogues which are often expensive, limited in efficacy and carry detrimental adverse effects. Cost-effective options for treatment exists in the form of herbal drugs, however, scientific validations of these widely used medicinal plants are still underway. Alternative splicing (AS) is a co-ordinated post-transcriptional process in which a single gene generates multiple mRNA transcripts which results in increased amounts of functionally different protein isoforms and in some cases aberrant splicing leads to metabolic disease. In this review, we explore the association of AS with metabolic alterations in DM and the biological significance of the abnormal splicing of some pathogenic diabetes-related genes. An understanding of the molecular mechanism behind abnormally spliced transcripts will aid in the development of new diagnostic, prognostic and therapeutic tools.
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Affiliation(s)
- Zodwa Dlamini
- ResearchInnovation & Engagements Portfolio, Mangosuthu University of Technology, Durban, South Africa
| | - Fortunate Mokoena
- ResearchInnovation & Engagements Portfolio, Mangosuthu University of Technology, Durban, South Africa
| | - Rodney Hull
- ResearchInnovation & Engagements Portfolio, Mangosuthu University of Technology, Durban, South Africa
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27
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Connolly PF, Fearnhead HO. Viral hijacking of host caspases: an emerging category of pathogen-host interactions. Cell Death Differ 2017; 24:1401-1410. [PMID: 28524855 PMCID: PMC5520459 DOI: 10.1038/cdd.2017.59] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/14/2017] [Accepted: 03/27/2017] [Indexed: 02/07/2023] Open
Abstract
Viruses co-evolve with their hosts, and many viruses have developed mechanisms to suppress or modify the host cell apoptotic response for their own benefit. Recently, evidence has emerged for the opposite strategy. Some viruses have developed the ability to co-opt apoptotic caspase activity to facilitate their own proliferation. In these strategies, viral proteins are cleaved by host caspases to create cleavage products with novel activities which facilitate viral replication. This represents a novel and interesting class of viral-host interactions, and also represents a new group of non-apoptotic roles for caspases. Here we review the evidence for such strategies, and discuss their origins and their implications for our understanding of the relationship between viral pathogenesis and programmed cell death.
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Affiliation(s)
- Patrick F Connolly
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, Galway, Ireland
| | - Howard O Fearnhead
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, Galway, Ireland
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28
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Mutations in CRADD Result in Reduced Caspase-2-Mediated Neuronal Apoptosis and Cause Megalencephaly with a Rare Lissencephaly Variant. Am J Hum Genet 2016; 99:1117-1129. [PMID: 27773430 PMCID: PMC5097945 DOI: 10.1016/j.ajhg.2016.09.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/19/2016] [Indexed: 12/02/2022] Open
Abstract
Lissencephaly is a malformation of cortical development typically caused by deficient neuronal migration resulting in cortical thickening and reduced gyration. Here we describe a “thin” lissencephaly (TLIS) variant characterized by megalencephaly, frontal predominant pachygyria, intellectual disability, and seizures. Trio-based whole-exome sequencing and targeted re-sequencing identified recessive mutations of CRADD in six individuals with TLIS from four unrelated families of diverse ethnic backgrounds. CRADD (also known as RAIDD) is a death-domain-containing adaptor protein that oligomerizes with PIDD and caspase-2 to initiate apoptosis. TLIS variants cluster in the CRADD death domain, a platform for interaction with other death-domain-containing proteins including PIDD. Although caspase-2 is expressed in the developing mammalian brain, little is known about its role in cortical development. CRADD/caspase-2 signaling is implicated in neurotrophic factor withdrawal- and amyloid-β-induced dendritic spine collapse and neuronal apoptosis, suggesting a role in cortical sculpting and plasticity. TLIS-associated CRADD variants do not disrupt interactions with caspase-2 or PIDD in co-immunoprecipitation assays, but still abolish CRADD’s ability to activate caspase-2, resulting in reduced neuronal apoptosis in vitro. Homozygous Cradd knockout mice display megalencephaly and seizures without obvious defects in cortical lamination, supporting a role for CRADD/caspase-2 signaling in mammalian brain development. Megalencephaly and lissencephaly associated with defective programmed cell death from loss of CRADD function in humans implicate reduced apoptosis as an important pathophysiological mechanism of cortical malformation. Our data suggest that CRADD/caspase-2 signaling is critical for normal gyration of the developing human neocortex and for normal cognitive ability.
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29
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Alternative splicing and cell survival: from tissue homeostasis to disease. Cell Death Differ 2016; 23:1919-1929. [PMID: 27689872 DOI: 10.1038/cdd.2016.91] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/26/2016] [Accepted: 07/15/2016] [Indexed: 12/17/2022] Open
Abstract
Most human genes encode multiple mRNA variants and protein products through alternative splicing of exons and introns during pre-mRNA processing. In this way, alternative splicing amplifies enormously the coding potential of the human genome and represents a powerful evolutionary resource. Nonetheless, the plasticity of its regulation is prone to errors and defective splicing underlies a large number of inherited and sporadic diseases, including cancer. One key cellular process affected by alternative splicing is the programmed cell death or apoptosis. Many apoptotic genes encode for splice variants having opposite roles in cell survival. This regulation modulates cell and tissue homeostasis and is implicated in both developmental and pathological processes. Furthermore, recent evidence has also unveiled splicing-mediated regulation of genes involved in autophagy, another essential process for tissue homeostasis. In this review, we highlight some of the best-known examples of alternative splicing events involved in cell survival. Emphasis is given to the role of this regulation in human cancer and in the response to chemotherapy, providing examples of how alternative splicing of apoptotic genes can be exploited therapeutically.
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30
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Crocetin exploits p53-induced death domain (PIDD) and FAS-associated death domain (FADD) proteins to induce apoptosis in colorectal cancer. Sci Rep 2016; 6:32979. [PMID: 27622714 PMCID: PMC5020693 DOI: 10.1038/srep32979] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 07/12/2016] [Indexed: 12/22/2022] Open
Abstract
Tumor suppressor p53 preserves the genomic integrity by restricting anomaly at the gene level. The hotspots for mutation in half of all colon cancers reside in p53. Hence, in a p53-mutated cellular milieu targeting cancer cells may be achievable by targeting the paralogue(s) of p53. Here we have shown the effectiveness of crocetin, a dietary component, in inducing apoptosis of colon cancer cells with varying p53 status. In wild-type p53-expressing cancer cells, p53 in one hand transactivates BAX and in parallel up-regulates p53-induced death domain protein (PIDD) that in turn cleaves and activates BID through caspase-2. Both BAX and t-BID converge at mitochondria to alter the transmembrane potential thereby leading to caspase-9 and caspase-3-mediated apoptosis. In contrast, in functional p53-impaired cells, this phytochemical exploits p53-paralogue p73, which up-regulates FAS to cleave BID through FAS-FADD-caspase-8-pathway. These findings not only underline the phenomenon of functional switch-over from p53 to p73 in p53-impaired condition, but also validate p73 as a promising and potential target for cancer therapy in absence of functional p53.
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31
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Trump BF. Mechanisms of Toxicity and Carcinogenesis. Toxicol Pathol 2016. [DOI: 10.1177/019262339502300616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
Apoptosis is a form of cellular suicide in which the cell activates an intrinsic program to bring about its own demise. Recognized for years as the mechanism by which developing cells are lost naturally, it has become apparent recently that this same process may play an important role in many acute and chronic diseases in which neural cell death occurs, such as stroke and Alzheimer's disease. This growing recognition suggests that a knowledge of the gene products controlling this process may lead to improved treatments for some disease states, as well as to improved understanding of neuronal development, physiology, and pathophysiology. Some controls with important roles in neural apoptosis have been identified, and these controls, as well as their putative mechanisms of action, are described in this article. NEUROSCIENTIST 2:181-190, 1996
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Affiliation(s)
- Dale E. Bredesen
- Program on Aging La Jolla Cancer Research Foundation
La Jolla, California
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33
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Juan-Mateu J, Villate O, Eizirik DL. MECHANISMS IN ENDOCRINOLOGY: Alternative splicing: the new frontier in diabetes research. Eur J Endocrinol 2016; 174:R225-38. [PMID: 26628584 PMCID: PMC5331159 DOI: 10.1530/eje-15-0916] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/01/2015] [Indexed: 12/30/2022]
Abstract
Type 1 diabetes (T1D) is a chronic autoimmune disease in which pancreatic β cells are killed by infiltrating immune cells and by cytokines released by these cells. This takes place in the context of a dysregulated dialogue between invading immune cells and target β cells, but the intracellular signals that decide β cell fate remain to be clarified. Alternative splicing (AS) is a complex post-transcriptional regulatory mechanism affecting gene expression. It regulates the inclusion/exclusion of exons into mature mRNAs, allowing individual genes to produce multiple protein isoforms that expand the proteome diversity. Functionally related transcript populations are co-ordinately spliced by master splicing factors, defining regulatory networks that allow cells to rapidly adapt their transcriptome in response to intra and extracellular cues. There is a growing interest in the role of AS in autoimmune diseases, but little is known regarding its role in T1D. In this review, we discuss recent findings suggesting that splicing events occurring in both immune and pancreatic β cells contribute to the pathogenesis of T1D. Splicing switches in T cells and in lymph node stromal cells are involved in the modulation of the immune response against β cells, while β cells exposed to pro-inflammatory cytokines activate complex splicing networks that modulate β cell viability, expression of neoantigens and susceptibility to immune-induced stress. Unveiling the role of AS in β cell functional loss and death will increase our understanding of T1D pathogenesis and may open new avenues for disease prevention and therapy.
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Affiliation(s)
- Jonàs Juan-Mateu
- Medical FacultyULB Center for Diabetes Research and Welbio, Université Libre de Bruxelles (ULB), Route de Lennik, 808 - CP618, B-1070 Brussels, Belgium
| | - Olatz Villate
- Medical FacultyULB Center for Diabetes Research and Welbio, Université Libre de Bruxelles (ULB), Route de Lennik, 808 - CP618, B-1070 Brussels, Belgium
| | - Décio L Eizirik
- Medical FacultyULB Center for Diabetes Research and Welbio, Université Libre de Bruxelles (ULB), Route de Lennik, 808 - CP618, B-1070 Brussels, Belgium
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Tang L, Shen H, Li X, Li Z, Liu Z, Xu J, Ma S, Zhao X, Bai X, Li M, Wang Q, Ji J. MiR-125a-5p decreases after long non-coding RNA HOTAIR knockdown to promote cancer cell apoptosis by releasing caspase 2. Cell Death Dis 2016; 7:e2137. [PMID: 26962687 PMCID: PMC4823942 DOI: 10.1038/cddis.2016.41] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/30/2016] [Accepted: 02/02/2016] [Indexed: 01/01/2023]
Abstract
HOTAIR (homeobox transcript antisense RNA), one of the prototypical long non-coding RNAs, has been verified overexpressed in multiple carcinomas and has emerged as a promising novel anticancer target. Its well-established role is acting as a predictor of poor prognosis and promoting cancer cell metastasis. Recently, another important mission of HOTAIR was uncovered that targeting HOTAIR caused cancer cell apoptosis. Nevertheless, so far there is no published data elaborating the mechanism. Here, we report that microRNA miR-125a-5p decreases and releases caspase 2 to promote cancer cell apoptosis after HOTAIR knockdown. We applied siRNAs targeting HOTAIR to various cancer cells, and observed apoptosis in all of these cell lines. RNA sequencing detected that miR-125a-5p was decreased after HOTAIR knockdown and miR-125a-5p mimics could rescue the apoptosis induced by HOTAIR deficiency. Luciferase assays identified caspase 2, an initiator caspase, to be a new target of miR-125a-5p. Elevated expression and subsequent cleavage of caspase 2 was observed after HOTAIR knockdown or inhibition of miR-125a-5p. RNAi of caspase 2 could attenuate the apoptosis induced by HOTAIR knockdown. In 80 clinical colon cancer tissues, HOTAIR and miR-125a-5p levels were higher than adjacent tissues, whereas caspase 2 was lower. MiR-125a-5p expression level was significantly correlated with colon tumor size, lymph node metastasis and clinical stage. These findings indicate that miR-125a-5p decreases after HOTAIR knockdown to promote cancer cell apoptosis by releasing caspase 2. Our work reveals a previously unidentified apoptotic mechanism, which might be exploitable in anticancer drug development.
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Affiliation(s)
- L Tang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - H Shen
- Key Laboratory of Genomics and Precision Medicine, China Gastrointestinal Cancer Research Center, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - X Li
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Z Li
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Z Liu
- Institute of Forensic Science, Ministry of Public Security, Beijing, China
| | - J Xu
- Institute of Forensic Science, Ministry of Public Security, Beijing, China
| | - S Ma
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - X Zhao
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - X Bai
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - M Li
- Department of General Surgery, Beijing ChaoYang Hospital, Capital University of Medical Sciences, Beijing, China
| | - Q Wang
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - J Ji
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
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35
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Caspase-2 resides in the mitochondria and mediates apoptosis directly from the mitochondrial compartment. Cell Death Discov 2016; 2. [PMID: 27019748 PMCID: PMC4806400 DOI: 10.1038/cddiscovery.2016.5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Caspase-2 plays an important role in apoptosis induced by several stimuli, including oxidative stress. However, the subcellular localization of caspase-2, particularly its presence in the mitochondria, is unclear. It is also not known if cytosolic caspase-2 translocates to the mitochondria to trigger the intrinsic pathway of apoptosis or if caspase-2 is constitutively present in the mitochondria that then selectively mediates this apoptotic effect. Here, we demonstrate the presence of caspase-2 in purified mitochondrial fractions from in vitro-cultured cells and in liver hepatocytes using immunoblots and confocal microscopy. We show that mitochondrial caspase-2 is functionally active by performing fluorescence resonance energy transfer analyses using a mitochondrially targeted substrate flanked by donor and acceptor fluorophores. Cell-free apoptotic assays involving recombination of nuclear, cytosolic and mitochondrial fractions from the livers of wild type and Casp2−/− mice clearly point to a direct functional role for mitochondrial caspase-2 in apoptosis. Furthermore, cytochrome c release from Casp2−/− cells is decreased as compared with controls upon treatment with agents inducing mitochondrial dysfunction. Finally, we show that Casp2−/− primary skin fibroblasts are protected from oxidants that target the mitochondrial electron transport chain. Taken together, our results demonstrate that caspase-2 exists in the mitochondria and that it is essential for mitochondrial oxidative stress-induced apoptosis.
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Abstract
The role of caspase proteases in regulated processes such as apoptosis and inflammation has been studied for more than two decades, and the activation cascades are known in detail. Apoptotic caspases also are utilized in critical developmental processes, although it is not known how cells maintain the exquisite control over caspase activity in order to retain subthreshold levels required for a particular adaptive response while preventing entry into apoptosis. In addition to active site-directed inhibitors, caspase activity is modulated by post-translational modifications or metal binding to allosteric sites on the enzyme, which stabilize inactive states in the conformational ensemble. This review provides a comprehensive global view of the complex conformational landscape of caspases and mechanisms used to select states in the ensemble. The caspase structural database provides considerable detail on the active and inactive conformations in the ensemble, which provide the cell multiple opportunities to fine tune caspase activity. In contrast, the current database on caspase modifications is largely incomplete and thus provides only a low-resolution picture of global allosteric communications and their effects on the conformational landscape. In recent years, allosteric control has been utilized in the design of small drug compounds or other allosteric effectors to modulate caspase activity.
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Affiliation(s)
- A Clay Clark
- Department of Biology, University of Texas at Arlington , Arlington, Texas 76019, United States
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37
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Ye S, Gao Y, Wang S, Li Q, Li R, Li H. Characterization and expression analysis of a caspase-2 in an invertebrate echinoderm sea cumber Apostichopus japonicus. FISH & SHELLFISH IMMUNOLOGY 2016; 48:266-272. [PMID: 26687532 DOI: 10.1016/j.fsi.2015.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/26/2015] [Accepted: 12/05/2015] [Indexed: 06/05/2023]
Abstract
Caspase-2 is the most evolutionarily conserved member of the caspase family which mediates the programmed cell death and plays crucial roles in key cellular processes. In this study, a caspase-2 homolog was identified and functionally characterized in sea cucumber Apostichopus japonicus, which we named AjCASP. The full-length cDNA consists of 2100 bp with an ORF encoding a protein of 378 amino acids. The deduced amino acid sequence shows that AjCASP consists of a conserved CARD-CASP2 domain and a CASs domain containing two active residues, two proteolytic cleavage residues, a substrate pocket and a dimer interface as well. In addition, a p20 large subunit with a characteristic five-peptide motif (QACRG) and a p10 small subunit in C-terminal were identified in CASs domain. Above data demonstrated that AjCASP is similar to CED-3 (the caspase-2 homolog of nematode Caenorhabditis elegans), which is further confirmed by phylogenetic tree analysis. AjCASP was ubiquitously expressed in sea cucumber and the obviously higher expression level was observed in coelomocyte, respiratory tree and intestine. Real-time PCR analyses further demonstrated that AjCASP was significantly induced by LPS. Taken together, these results strongly suggest that AjCASP is a caspase-2 homolog and it may be involved in invertebrate immune response, especially in eliminating and degrading invading pathogens.
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Affiliation(s)
| | | | | | | | | | - Hua Li
- Dalian Ocean University, China.
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38
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Thompson R, Shah RB, Liu PH, Gupta YK, Ando K, Aggarwal AK, Sidi S. An Inhibitor of PIDDosome Formation. Mol Cell 2015; 58:767-79. [PMID: 25936804 DOI: 10.1016/j.molcel.2015.03.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 02/25/2015] [Accepted: 03/27/2015] [Indexed: 12/31/2022]
Abstract
The PIDDosome-PIDD-RAIDD-caspase-2 complex-is a proapoptotic caspase-activation platform of elusive significance. DNA damage can initiate complex assembly via ATM phosphorylation of the PIDD death domain (DD), which enables RAIDD recruitment to PIDD. In contrast, the mechanisms limiting PIDDosome formation have remained unclear. We identify the mitotic checkpoint factor BubR1 as a direct PIDDosome inhibitor, acting in a noncanonical role independent of Mad2. Following its phosphorylation by ATM at DNA breaks, "primed" PIDD relocates to kinetochores via a direct interaction with BubR1. BubR1 binds the PIDD DD, competes with RAIDD recruitment, and negates PIDDosome-mediated apoptosis after ionizing radiation. The PIDDosome thus sequentially integrates DNA damage and mitotic checkpoint signals to decide cell fate in response to genotoxic stress. We further show that by sequestering PIDD at the kinetochore, BubR1 acts to delay PIDDosome formation until the next cycle, defining a new mechanism by which cells evade apoptosis during mitosis.
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Affiliation(s)
- Ruth Thompson
- Department of Medicine, Division of Hematology/Oncology, The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Richa B Shah
- Department of Medicine, Division of Hematology/Oncology, The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Peter H Liu
- Department of Medicine, Division of Hematology/Oncology, The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yogesh K Gupta
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kiyohiro Ando
- Department of Medicine, Division of Hematology/Oncology, The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Aneel K Aggarwal
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Samuel Sidi
- Department of Medicine, Division of Hematology/Oncology, The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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39
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Jackson TC, Du L, Janesko-Feldman K, Vagni VA, Dezfulian C, Poloyac SM, Jackson EK, Clark RSB, Kochanek PM. The nuclear splicing factor RNA binding motif 5 promotes caspase activation in human neuronal cells, and increases after traumatic brain injury in mice. J Cereb Blood Flow Metab 2015; 35:655-66. [PMID: 25586139 PMCID: PMC4420885 DOI: 10.1038/jcbfm.2014.242] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/06/2014] [Accepted: 12/08/2014] [Indexed: 12/31/2022]
Abstract
Splicing factors (SFs) coordinate nuclear intron/exon splicing of RNA. Splicing factor disturbances can cause cell death. RNA binding motif 5 (RBM5) and 10 (RBM10) promote apoptosis in cancer cells by activating detrimental alternative splicing of key death/survival genes. The role(s) of RBM5/10 in neurons has not been established. Here, we report that RBM5 knockdown in human neuronal cells decreases caspase activation by staurosporine. In contrast, RBM10 knockdown augments caspase activation. To determine whether brain injury alters RBM signaling, we measured RBM5/10 protein in mouse cortical/hippocampus homogenates after controlled cortical impact (CCI) traumatic brain injury (TBI) plus hemorrhagic shock (CCI+HS). The RBM5/10 staining was higher 48 to 72 hours after injury and appeared to be increased in neuronal nuclei of the hippocampus. We also measured levels of other nuclear SFs known to be essential for cellular viability and report that splicing factor 1 (SF1) but not splicing factor 3A (SF3A) decreased 4 to 72 hours after injury. Finally, we confirm that RBM5/10 regulate protein expression of several target genes including caspase-2, cellular FLICE-like inhibitory protein (c-FLIP), LETM1 Domain-Containing Protein 1 (LETMD1), and amyloid precursor-like protein 2 (APLP2) in neuronal cells. Knockdown of RBM5 appeared to increase expression of c-FLIP(s), LETMD1, and APLP2 but decrease caspase-2.
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Affiliation(s)
- Travis C Jackson
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Lina Du
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Keri Janesko-Feldman
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Vincent A Vagni
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Cameron Dezfulian
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Samuel M Poloyac
- Pharmaceutical Sciences Department, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania, USA
| | - Edwin K Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Robert S B Clark
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Patrick M Kochanek
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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40
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Chen FC. Alternative RNA structure-coupled gene regulations in tumorigenesis. Int J Mol Sci 2014; 16:452-75. [PMID: 25551597 PMCID: PMC4307256 DOI: 10.3390/ijms16010452] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/16/2014] [Indexed: 12/11/2022] Open
Abstract
Alternative RNA structures (ARSs), or alternative transcript isoforms, are critical for regulating cellular phenotypes in humans. In addition to generating functionally diverse protein isoforms from a single gene, ARS can alter the sequence contents of 5'/3' untranslated regions (UTRs) and intronic regions, thus also affecting the regulatory effects of these regions. ARS may introduce premature stop codon(s) into a transcript, and render the transcript susceptible to nonsense-mediated decay, which in turn can influence the overall gene expression level. Meanwhile, ARS can regulate the presence/absence of upstream open reading frames and microRNA targeting sites in 5'UTRs and 3'UTRs, respectively, thus affecting translational efficiencies and protein expression levels. Furthermore, since ARS may alter exon-intron structures, it can influence the biogenesis of intronic microRNAs and indirectly affect the expression of the target genes of these microRNAs. The connections between ARS and multiple regulatory mechanisms underline the importance of ARS in determining cell fate. Accumulating evidence indicates that ARS-coupled regulations play important roles in tumorigenesis. Here I will review our current knowledge in this field, and discuss potential future directions.
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Affiliation(s)
- Feng-Chi Chen
- Institute of Population Health Sciences, National Health Research Institutes, Miaoli County 350, Taiwan.
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41
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Molecular cloning of two molluscan caspases and gene functional analysis during Crassostrea angulata (Fujian oyster) larval metamorphosis. Mol Biol Rep 2014; 42:963-75. [DOI: 10.1007/s11033-014-3833-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
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42
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Attenuation of the ELAV1-like protein HuR sensitizes adenocarcinoma cells to the intrinsic apoptotic pathway by increasing the translation of caspase-2L. Cell Death Dis 2014; 5:e1321. [PMID: 25010987 PMCID: PMC4123073 DOI: 10.1038/cddis.2014.279] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 05/16/2014] [Accepted: 05/20/2014] [Indexed: 12/22/2022]
Abstract
Caspase-2 represents the most conserved member of the caspase family, which exhibits features of both initiator and effector caspases. Using ribonucleoprotein (RNP)-immunoprecipitation assay, we identified the proapoptotic caspase-2L encoding mRNA as a novel target of the ubiquitous RNA-binding protein HuR in DLD-1 colon carcinoma cells. Unexpectedly, crosslinking-RNP and RNA probe pull-down experiments revealed that HuR binds exclusively to the caspase-2-5' untranslated region (UTR) despite that the 3' UTR of the mRNA bears several adenylate- and uridylate-rich elements representing the prototypical HuR binding sites. By using RNAi-mediated loss-of-function approach, we observed that HuR regulates the mRNA and in turn the protein levels of caspase-2 in a negative manner. Silencing of HuR did not affect the stability of caspase-2 mRNA but resulted in an increased redistribution of caspase-2 transcripts from RNP particles to translational active polysomes implicating that HuR exerts a direct repressive effect on caspase-2 translation. Consistently, in vitro translation of a luciferase reporter gene under the control of an upstream caspase-2-5'UTR was strongly impaired after the addition of recombinant HuR, whereas translation of caspase-2 coding region without the 5'UTR is not affected by HuR confirming the functional role of the caspase-2-5'UTR. Functionally, an elevation in caspase-2 level by HuR knockdown correlated with an increased sensitivity of cells to apoptosis induced by staurosporine- and pore-forming toxins as implicated by their significant accumulation in the sub G1 phase and an increase in caspase-2, -3 and poly ADP-ribose polymerase cleavage, respectively. Importantly, HuR knockdown cells remained insensitive toward STS-induced apoptosis if cells were additionally transfected with caspase-2-specific siRNAs. Collectively, our findings support the hypothesis that HuR by acting as an endogenous inhibitor of caspase-2-driven apoptosis may essentially contribute to the antiapoptotic program of adenocarcinoma cells by HuR.
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43
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Ghiretti AE, Paradis S. Molecular mechanisms of activity-dependent changes in dendritic morphology: role of RGK proteins. Trends Neurosci 2014; 37:399-407. [PMID: 24910262 PMCID: PMC4113564 DOI: 10.1016/j.tins.2014.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 01/10/2023]
Abstract
The nervous system has the amazing capacity to transform sensory experience from the environment into changes in neuronal activity that, in turn, cause long-lasting alterations in neuronal morphology. Recent findings indicate that, surprisingly, sensory experience concurrently activates molecular signaling pathways that both promote and inhibit dendritic complexity. Historically, a number of positive regulators of activity-dependent dendritic complexity have been described, whereas the list of identified negative regulators of this process is much shorter. In recent years, there has been an emerging appreciation of the importance of the Rad/Rem/Rem2/Gem/Kir (RGK) GTPases as mediators of activity-dependent structural plasticity. In the following review, we discuss the traditional view of RGK proteins, as well as our evolving understanding of the role of these proteins in instructing structural plasticity.
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Affiliation(s)
- Amy E Ghiretti
- Department of Biology, National Center for Behavioral Genomics, and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
| | - Suzanne Paradis
- Department of Biology, National Center for Behavioral Genomics, and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA.
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44
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Hua Y, Nair S. Proteases in cardiometabolic diseases: Pathophysiology, molecular mechanisms and clinical applications. Biochim Biophys Acta Mol Basis Dis 2014; 1852:195-208. [PMID: 24815358 DOI: 10.1016/j.bbadis.2014.04.032] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 04/25/2014] [Accepted: 04/30/2014] [Indexed: 12/21/2022]
Abstract
Cardiovascular disease is the leading cause of death in the U.S. and other developed countries. Metabolic syndrome, including obesity, diabetes/insulin resistance, hypertension and dyslipidemia is a major threat for public health in the modern society. It is well established that metabolic syndrome contributes to the development of cardiovascular disease collective called as cardiometabolic disease. Despite documented studies in the research field of cardiometabolic disease, the underlying mechanisms are far from clear. Proteases are enzymes that break down proteins, many of which have been implicated in various diseases including cardiac disease. Matrix metalloproteinase (MMP), calpain, cathepsin and caspase are among the major proteases involved in cardiac remodeling. Recent studies have also implicated proteases in the pathogenesis of cardiometabolic disease. Elevated expression and activities of proteases in atherosclerosis, coronary heart disease, obesity/insulin-associated heart disease as well as hypertensive heart disease have been documented. Furthermore, transgenic animals that are deficient in or over-express proteases allow scientists to understand the causal relationship between proteases and cardiometabolic disease. Mechanistically, MMPs and cathepsins exert their effect on cardiometabolic diseases mainly through modifying the extracellular matrix. However, MMP and cathepsin are also reported to affect intracellular proteins, by which they contribute to the development of cardiometabolic diseases. On the other hand, activation of calpain and caspases has been shown to influence intracellular signaling cascade including the NF-κB and apoptosis pathways. Clinically, proteases are reported to function as biomarkers of cardiometabolic diseases. More importantly, the inhibitors of proteases are credited with beneficial cardiometabolic profile, although the exact molecular mechanisms underlying these salutary effects are still under investigation. A better understanding of the role of MMPs, cathepsins, calpains and caspases in cardiometabolic diseases process may yield novel therapeutic targets for treating or controlling these diseases. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases.
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Affiliation(s)
- Yinan Hua
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, School of Pharmacy, College of Health Sciences, Laramie, WY 82071, USA.
| | - Sreejayan Nair
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, School of Pharmacy, College of Health Sciences, Laramie, WY 82071, USA.
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45
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Sharma R, Callaway D, Vanegas D, Bendele M, Lopez-Cruzan M, Horn D, Guda T, Fajardo R, Abboud-Werner S, Herman B. Caspase-2 maintains bone homeostasis by inducing apoptosis of oxidatively-damaged osteoclasts. PLoS One 2014; 9:e93696. [PMID: 24691516 PMCID: PMC3972236 DOI: 10.1371/journal.pone.0093696] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 03/10/2014] [Indexed: 01/01/2023] Open
Abstract
Osteoporosis is a silent disease, characterized by a porous bone micro-structure that enhances risk for fractures and associated disabilities. Senile, or age-related osteoporosis (SO), affects both men and women, resulting in increased morbidity and mortality. However, cellular and molecular mechanisms underlying senile osteoporosis are not fully known. Recent studies implicate the accumulation of reactive oxygen species (ROS) and increased oxidative stress as key factors in SO. Herein, we show that loss of caspase-2, a cysteine aspartate protease involved in oxidative stress-induced apoptosis, results in total body and femoral bone loss in aged mice (20% decrease in bone mineral density), and an increase in bone fragility (30% decrease in fracture strength). Importantly, we demonstrate that genetic ablation or selective inhibition of caspase-2 using zVDVAD-fmk results in increased numbers of bone-resorbing osteoclasts and enhanced tartrate-resistant acid phosphatase (TRAP) activity. Conversely, transfection of osteoclast precursors with wild type caspase-2 but not an enzymatic mutant, results in a decrease in TRAP activity. We demonstrate that caspase-2 expression is induced in osteoclasts treated with oxidants such as hydrogen peroxide and that loss of caspase-2 enhances resistance to oxidants, as measured by TRAP activity, and decreases oxidative stress-induced apoptosis of osteoclasts. Moreover, oxidative stress, quantified by assessment of the lipid peroxidation marker, 4-HNE, is increased in Casp2-/- bone, perhaps due to a decrease in antioxidant enzymes such as SOD2. Taken together, our data point to a critical and novel role for caspase-2 in maintaining bone homeostasis by modulating ROS levels and osteoclast apoptosis during conditions of enhanced oxidative stress that occur during aging.
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Affiliation(s)
- Ramaswamy Sharma
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Danielle Callaway
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Difernando Vanegas
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Michelle Bendele
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Marisa Lopez-Cruzan
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Diane Horn
- Department of Pathology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Teja Guda
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Roberto Fajardo
- Department of Orthopedics, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Sherry Abboud-Werner
- Department of Pathology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Brian Herman
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- * E-mail:
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46
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Analysis of the minimal specificity of caspase-2 and identification of Ac-VDTTD-AFC as a caspase-2-selective peptide substrate. Biosci Rep 2014; 34:BSR20140025. [PMID: 27919034 PMCID: PMC3966047 DOI: 10.1042/bsr20140025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 02/12/2014] [Accepted: 02/13/2014] [Indexed: 11/17/2022] Open
Abstract
Caspase-2 is an evolutionarily conserved but enigmatic protease whose biological role remains poorly understood. To date, research into the functions of caspase-2 has been hampered by an absence of reagents that can distinguish its activity from that of the downstream apoptotic caspase, caspase-3. Identification of protein substrates of caspase-2 that are efficiently cleaved within cells may also provide clues to the role of this protease. We used a yeast-based transcriptional reporter system to define the minimal substrate specificity of caspase-2. The resulting profile enabled the identification of candidate novel caspase-2 substrates. Caspase-2 cleaved one of these proteins, the cancer-associated transcription factor Runx1, although with relatively low efficiency. A fluorogenic peptide was derived from the sequence most efficiently cleaved in the context of the transcriptional reporter. This peptide, Ac-VDTTD-AFC, was efficiently cleaved by purified caspase-2 and auto-activating caspase-2 in mammalian cells, and exhibited better selectivity for caspase-2 relative to caspase-3 than reagents that are currently available. We suggest that this reagent, used in parallel with the traditional caspase-3 substrate Ac-DEVD-AFC, will enable researchers to monitor caspase-2 activity in cell lysates and may assist in the determination of stimuli that activate caspase-2 in vivo.
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47
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Abstract
A key feature of the CNS is structural plasticity, the ability of neurons to alter their morphology and connectivity in response to sensory experience and other changes in the environment. How this structural plasticity is achieved at the molecular level is not well understood. We provide evidence that changes in sensory experience simultaneously trigger multiple signaling pathways that either promote or restrict growth of the dendritic arbor; structural plasticity is achieved through a balance of these opposing signals. Specifically, we have uncovered a novel, activity-dependent signaling pathway that restricts dendritic arborization. We demonstrate that the GTPase Rem2 is regulated at the transcriptional level by calcium influx through L-VGCCs and inhibits dendritic arborization in cultured rat cortical neurons and in the Xenopus laevis tadpole visual system. Thus, our results demonstrate that changes in neuronal activity initiate competing signaling pathways that positively and negatively regulate the growth of the dendritic arbor. It is the balance of these opposing signals that leads to proper dendritic morphology.
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48
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Inoue A, Yamamoto N, Kimura M, Nishio K, Yamane H, Nakajima K. RBM10 regulates alternative splicing. FEBS Lett 2014; 588:942-7. [PMID: 24530524 DOI: 10.1016/j.febslet.2014.01.052] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 12/02/2013] [Accepted: 01/23/2014] [Indexed: 12/30/2022]
Abstract
RBM10, originally called S1-1, is a nuclear RNA-binding protein with domains characteristic of RNA processing proteins. It has been reported that RBM10 constitutes spliceosome complexes and that RBM5, a close homologue of RBM10, regulates alternative splicing of apoptosis-related genes, Fas and cFLIP. In this study, we examined whether RBM10 has a regulatory function in splicing similar to RBM5, and determined that it indeed regulates alternative splicing of Fas and Bcl-x genes. RBM10 promotes exon skipping of Fas pre-mRNA as well as selection of an internal 5'-splice site in Bcl-x pre-mRNA. We propose a consensus RBM10-binding sequence at 5'-splice sites of target exons and a mechanistic model of RBM10 action in the alternative splicing.
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Affiliation(s)
- Akira Inoue
- Department of Immunology, Osaka City University Graduate School of Medicine, Japan; Department of Otolaryngology, Osaka City University Graduate School of Medicine, Japan.
| | - Naoki Yamamoto
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Japan
| | - Masatsugu Kimura
- Department of Radioisotope Center, Osaka City University Graduate School of Medicine, Japan
| | - Koji Nishio
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Nagoya University, Japan
| | - Hideo Yamane
- Department of Otolaryngology, Osaka City University Graduate School of Medicine, Japan
| | - Koichi Nakajima
- Department of Immunology, Osaka City University Graduate School of Medicine, Japan
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49
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DNA-damage-induced apoptosis. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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50
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Jang HN, Lee M, Loh TJ, Choi SW, Oh HK, Moon H, Cho S, Hong SE, Kim DH, Sheng Z, Green MR, Park D, Zheng X, Shen H. Exon 9 skipping of apoptotic caspase-2 pre-mRNA is promoted by SRSF3 through interaction with exon 8. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1839:25-32. [PMID: 24321384 DOI: 10.1016/j.bbagrm.2013.11.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/14/2013] [Accepted: 11/26/2013] [Indexed: 01/24/2023]
Abstract
Alternative splicing plays an important role in gene expression by producing different proteins from a gene. Caspase-2 pre-mRNA produces anti-apoptotic Casp-2S and pro-apoptotic Casp-2L proteins through exon 9 inclusion or skipping. However, the molecular mechanisms of exon 9 splicing are not well understood. Here we show that knockdown of SRSF3 (also known as SRp20) with siRNA induced significant increase of endogenous exon 9 inclusion. In addition, overexpression of SRSF3 promoted exon 9 skipping. Thus we conclude that SRSF3 promotes exon 9 skipping. In order to understand the functional target of SRSF3 on caspase-2 pre-mRNA, we performed substitution and deletion mutagenesis on the potential SRSF3 binding sites that were predicted from previous reports. We demonstrate that substitution mutagenesis of the potential SRSF3 binding site on exon 8 severely disrupted the effects of SRSF3 on exon 9 skipping. Furthermore, with the approach of RNA pulldown and immunoblotting analysis we show that SRSF3 interacts with the potential SRSF3 binding RNA sequence on exon 8 but not with the mutant RNA sequence. In addition, we show that a deletion of 26nt RNA from 5' end of exon 8, a 33nt RNA from 3' end of exon 10 and a 2225nt RNA from intron 9 did not compromise the function of SRSF3 on exon 9 splicing. Therefore we conclude that SRSF3 promotes exon 9 skipping of caspase-2 pre-mRNA by interacting with exon 8. Our results reveal a novel mechanism of caspase-2 pre-mRNA splicing.
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Affiliation(s)
- Ha Na Jang
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Minho Lee
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Tiing Jen Loh
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Seung-Woo Choi
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Hyun Kyung Oh
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Heegyum Moon
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Sunghee Cho
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Seong-Eui Hong
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Do Han Kim
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Zhi Sheng
- Virginia Tech Carilion Research Institute, Roanoke, VA, 24016, USA; Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Michael R Green
- Howard Hughes Medical Institute and Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Daeho Park
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Xuexiu Zheng
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Haihong Shen
- School of life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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