1
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Yang R, Zhang Y, Kang J, Zhang C, Ning B. Chondroitin Sulfate Proteoglycans Revisited: Its Mechanism of Generation and Action for Spinal Cord Injury. Aging Dis 2024; 15:153-168. [PMID: 37307832 PMCID: PMC10796098 DOI: 10.14336/ad.2023.0512] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 05/12/2023] [Indexed: 06/14/2023] Open
Abstract
Reactive astrocytes (RAs) produce chondroitin sulfate proteoglycans (CSPGs) in large quantities after spinal cord injury (SCI) and inhibit axon regeneration through the Rho-associated protein kinase (ROCK) pathway. However, the mechanism of producing CSPGs by RAs and their roles in other aspects are often overlooked. In recent years, novel generation mechanisms and functions of CSPGs have gradually emerged. Extracellular traps (ETs), a new recently discovered phenomenon in SCI, can promote secondary injury. ETs are released by neutrophils and microglia, which activate astrocytes to produce CSPGs after SCI. CSPGs inhibit axon regeneration and play an important role in regulating inflammation as well as cell migration and differentiation; some of these regulations are beneficial. The current review summarized the process of ET-activated RAs to generate CSPGs at the cellular signaling pathway level. Moreover, the roles of CSPGs in inhibiting axon regeneration, regulating inflammation, and regulating cell migration and differentiation were discussed. Finally, based on the above process, novel potential therapeutic targets were proposed to eliminate the adverse effects of CSPGs.
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Affiliation(s)
- Rui Yang
- Jinan Central Hospital, Shandong University, Jinan, Shandong, China.
| | - Ying Zhang
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Jianning Kang
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Ce Zhang
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Bin Ning
- Jinan Central Hospital, Shandong University, Jinan, Shandong, China.
- Central Hospital Affiliated to Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
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2
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The GCN5: its biological functions and therapeutic potentials. Clin Sci (Lond) 2021; 135:231-257. [PMID: 33443284 DOI: 10.1042/cs20200986] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022]
Abstract
General control non-depressible 5 (GCN5) or lysine acetyltransferase 2A (KAT2A) is one of the most highly studied histone acetyltransferases. It acts as both histone acetyltransferase (HAT) and lysine acetyltransferase (KAT). As an HAT it plays a pivotal role in the epigenetic landscape and chromatin modification. Besides, GCN5 regulates a wide range of biological events such as gene regulation, cellular proliferation, metabolism and inflammation. Imbalance in the GCN5 activity has been reported in many disorders such as cancer, metabolic disorders, autoimmune disorders and neurological disorders. Therefore, unravelling the role of GCN5 in different diseases progression is a prerequisite for both understanding and developing novel therapeutic agents of these diseases. In this review, we have discussed the structural features, the biological function of GCN5 and the mechanical link with the diseases associated with its imbalance. Moreover, the present GCN5 modulators and their limitations will be presented in a medicinal chemistry perspective.
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3
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Wilson C, Cáceres A. New insights on epigenetic mechanisms supporting axonal development: histone marks and miRNAs. FEBS J 2020; 288:6353-6364. [PMID: 33332753 DOI: 10.1111/febs.15673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/21/2020] [Accepted: 12/15/2020] [Indexed: 11/27/2022]
Abstract
Mechanisms supporting axon growth and the establishment of neuronal polarity have remained largely disconnected from their genetic and epigenetic fundamentals. Recently, post-transcriptional modifications of histones involved in chromatin folding and transcription, and microRNAs controlling translation have emerged as regulators of axonal specification, growth, and guidance. In this article, we review novel evidence supporting the concept that epigenetic mechanisms work at both transcriptional and post-transcriptional levels to shape axons. We also discuss the role of splicing on axonal growth, as one of the most (if not the most) powerful post-transcriptional mechanism to diversify genetic information. Overall, we think exploring the gap between epigenetics and axonal growth raises new questions and perspectives to the development of axons in physiological and pathological contexts.
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Affiliation(s)
- Carlos Wilson
- Centro de Investigación en Medicina Traslacional "Severo R Amuchástegui" (CIMETSA), Instituto Universitario Ciencias Biomédicas Córdoba (IUCBC), Córdoba, Argentina.,Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET-UNC), Córdoba, Argentina.,Universidad Nacional de Córdoba (UNC), Argentina
| | - Alfredo Cáceres
- Centro de Investigación en Medicina Traslacional "Severo R Amuchástegui" (CIMETSA), Instituto Universitario Ciencias Biomédicas Córdoba (IUCBC), Córdoba, Argentina
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4
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Vargas EJM, Matamoros AJ, Qiu J, Jan CH, Wang Q, Gorczyca D, Han TW, Weissman JS, Jan YN, Banerjee S, Song Y. The microtubule regulator ringer functions downstream from the RNA repair/splicing pathway to promote axon regeneration. Genes Dev 2020; 34:194-208. [PMID: 31919191 PMCID: PMC7000917 DOI: 10.1101/gad.331330.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/10/2019] [Indexed: 12/17/2022]
Abstract
In this study, Vargas et al. set out to elucidate the downstream effectors of the Rtca-mediated RNA repair/splicing pathway. Using genome-wide transcriptome analysis, the authors demonstrate that the microtubule-associated protein (MAP) tubulin polymerization-promoting protein (TPPP) ringer functions downstream from and is suppressed by Rtca via Xbp1-dependent transcription. Ringer cell-autonomously promotes axon regeneration in the peripheral and central nervous system. Promoting axon regeneration in the central and peripheral nervous system is of clinical importance in neural injury and neurodegenerative diseases. Both pro- and antiregeneration factors are being identified. We previously reported that the Rtca mediated RNA repair/splicing pathway restricts axon regeneration by inhibiting the nonconventional splicing of Xbp1 mRNA under cellular stress. However, the downstream effectors remain unknown. Here, through transcriptome profiling, we show that the tubulin polymerization-promoting protein (TPPP) ringmaker/ringer is dramatically increased in Rtca-deficient Drosophila sensory neurons, which is dependent on Xbp1. Ringer is expressed in sensory neurons before and after injury, and is cell-autonomously required for axon regeneration. While loss of ringer abolishes the regeneration enhancement in Rtca mutants, its overexpression is sufficient to promote regeneration both in the peripheral and central nervous system. Ringer maintains microtubule stability/dynamics with the microtubule-associated protein futsch/MAP1B, which is also required for axon regeneration. Furthermore, ringer lies downstream from and is negatively regulated by the microtubule-associated deacetylase HDAC6, which functions as a regeneration inhibitor. Taken together, our findings suggest that ringer acts as a hub for microtubule regulators that relays cellular status information, such as cellular stress, to the integrity of microtubules in order to instruct neuroregeneration.
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Affiliation(s)
- Ernest J Monahan Vargas
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Andrew J Matamoros
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jingyun Qiu
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Calvin H Jan
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Qin Wang
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - David Gorczyca
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
| | - Tina W Han
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA.,Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
| | - Swati Banerjee
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Yuanquan Song
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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5
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Kalinski AL, Kar AN, Craver J, Tosolini AP, Sleigh JN, Lee SJ, Hawthorne A, Brito-Vargas P, Miller-Randolph S, Passino R, Shi L, Wong VSC, Picci C, Smith DS, Willis DE, Havton LA, Schiavo G, Giger RJ, Langley B, Twiss JL. Deacetylation of Miro1 by HDAC6 blocks mitochondrial transport and mediates axon growth inhibition. J Cell Biol 2019; 218:1871-1890. [PMID: 31068376 PMCID: PMC6548128 DOI: 10.1083/jcb.201702187] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 02/15/2018] [Accepted: 04/15/2019] [Indexed: 02/08/2023] Open
Abstract
Inhibition of histone deacetylase 6 (HDAC6) was shown to support axon growth on the nonpermissive substrates myelin-associated glycoprotein (MAG) and chondroitin sulfate proteoglycans (CSPGs). Though HDAC6 deacetylates α-tubulin, we find that another HDAC6 substrate contributes to this axon growth failure. HDAC6 is known to impact transport of mitochondria, and we show that mitochondria accumulate in distal axons after HDAC6 inhibition. Miro and Milton proteins link mitochondria to motor proteins for axon transport. Exposing neurons to MAG and CSPGs decreases acetylation of Miro1 on Lysine 105 (K105) and decreases axonal mitochondrial transport. HDAC6 inhibition increases acetylated Miro1 in axons, and acetyl-mimetic Miro1 K105Q prevents CSPG-dependent decreases in mitochondrial transport and axon growth. MAG- and CSPG-dependent deacetylation of Miro1 requires RhoA/ROCK activation and downstream intracellular Ca2+ increase, and Miro1 K105Q prevents the decrease in axonal mitochondria seen with activated RhoA and elevated Ca2+ These data point to HDAC6-dependent deacetylation of Miro1 as a mediator of axon growth inhibition through decreased mitochondrial transport.
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Affiliation(s)
- Ashley L Kalinski
- Department of Biology, Drexel University, Philadelphia, PA.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | - John Craver
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | - Andrew P Tosolini
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | - Paul Brito-Vargas
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | - Ryan Passino
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Liang Shi
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | | | - Deanna S Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | - Leif A Havton
- Departments of Neurology and Neurobiology, University of California, Los Angeles, Los Angeles, CA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK.,Discoveries Centre for Regenerative and Precision Medicine, University College London Campus, London, UK
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | | | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC
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6
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Knockdown of Fidgetin Improves Regeneration of Injured Axons by a Microtubule-Based Mechanism. J Neurosci 2019; 39:2011-2024. [PMID: 30647150 DOI: 10.1523/jneurosci.1888-18.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/21/2018] [Accepted: 12/24/2018] [Indexed: 12/16/2022] Open
Abstract
Fidgetin is a microtubule-severing protein that pares back the labile domains of microtubules in the axon. Experimental depletion of fidgetin results in elongation of the labile domains of microtubules and faster axonal growth. To test whether fidgetin knockdown assists axonal regeneration, we plated dissociated adult rat DRGs transduced using AAV5-shRNA-fidgetin on a laminin substrate with spots of aggrecan, a growth-inhibitory chondroitin sulfate proteoglycan. This cell culture assay mimics the glial scar formed after CNS injury. Aggrecan is more concentrated at the edge of the spot, such that axons growing from within the spot toward the edge encounter a concentration gradient that causes growth cones to become dystrophic and axons to retract or curve back on themselves. Fidgetin knockdown resulted in faster-growing axons on both laminin and aggrecan and enhanced crossing of axons from laminin onto aggrecan. Strikingly, axons from within the spot grew more avidly against the inhibitory aggrecan concentration gradient to cross onto laminin, without retracting or curving back. We also tested whether depleting fidgetin improves axonal regeneration in vivo after a dorsal root crush in adult female rats. Whereas control DRG neurons failed to extend axons across the dorsal root entry zone after injury, DRG neurons in which fidgetin was knocked down displayed enhanced regeneration of axons across the dorsal root entry zone into the spinal cord. Collectively, these results establish fidgetin as a novel therapeutic target to augment nerve regeneration and provide a workflow template by which microtubule-related targets can be compared in the future.SIGNIFICANCE STATEMENT Here we establish a workflow template from cell culture to animals in which microtubule-based treatments can be tested and compared with one another for their effectiveness in augmenting regeneration of injured axons relevant to spinal cord injury. The present work uses a viral transduction approach to knock down fidgetin from rat neurons, which coaxes nerve regeneration by elevating microtubule mass in their axons. Unlike previous strategies using microtubule-stabilizing drugs, fidgetin knockdown adds microtubule mass that is labile (rather than stable), thereby better recapitulating the growth status of a developing axon.
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7
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Cocco E, Leo M, Canzonetta C, Di Vito S, Mai A, Rotili D, Di Napoli A, Vecchione A, De Nunzio C, Filetici P, Stoppacciaro A. KAT3B-p300 and H3AcK18/H3AcK14 levels are prognostic markers for kidney ccRCC tumor aggressiveness and target of KAT inhibitor CPTH2. Clin Epigenetics 2018; 10:44. [PMID: 29632619 PMCID: PMC5885315 DOI: 10.1186/s13148-018-0473-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/14/2018] [Indexed: 12/26/2022] Open
Abstract
Background Kidney cancer and clear cell renal carcinoma (ccRCC) are the 16th most common cause of death worldwide. ccRCC is often metastasized at diagnosis, and surgery remains the main treatment; therefore, early diagnosis and new therapeutic strategies are highly desirable. KAT inhibitor CPTH2 lowers histone H3 acetylation and induces apoptosis in colon cancer and cultured cerebellar granule neurons. In this study, we have evaluated the effects of CPTH2 on ccRCC 786-O cell line and analyzed drug targets expressed in ccRCC tumor tissues at different grade. Results CPTH2 decreases cell viability, adhesion, and invasiveness in ccRCC cell line 786-O. It shows preferential inhibition for KAT3B-p300 with hypoacetilating effects on histone H3 at specific H3-K18. Immunohistochemical analysis of 70 ccRCC tumor tissues compared with peritumoral normal epithelium showed a statistical significant reduction of p300/H3AcK18 paralleled by an increase of H3AcK14 in G1 grade and an opposed trend during tumor progression to worst grades. In this study, we demonstrate that these marks are CPTH2 targets and significative prognosticators of low-grade ccRCC tumor. Conclusions ccRCC is substantially insensitive to current therapies, and the efficacy of clinical treatment is dependent on the dissemination stage of the tumor. The present study shows that CPTH2 is able to induce apoptosis and decrease the invasiveness of a ccRCC cell line through the inhibition of KAT3B. In a tumor tissue analysis, we identified new prognosticator marks in grade G1 ccRCC tumors. Low KAT3B/H3AcK18 vs. high H3AcK14 were found in G1 while an opposed trend characterized tumor progression to worst grades. Our collected results suggest that CPTH2 reducing KAT3B and H3AcK18 can be considered a promising candidate for counteracting the progression of ccRCC tumors. Electronic supplementary material The online version of this article (10.1186/s13148-018-0473-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elisa Cocco
- 1Surgical Pathology Units, Department of Clinical and Molecular Medicine, Ospedale Sant'Andrea, La Sapienza University, Rome, Italy
| | - Manuela Leo
- 2Department of Biology and Biotechnology "C. Darwin", La Sapienza University of Rome, Rome, Italy
| | - Claudia Canzonetta
- 3Department of Immunology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Serena Di Vito
- 4Institute of Molecular Biology and Pathology-CNR, La Sapienza University of Rome, P.le, A. Moro 5, Rome, Italy
| | - Antonello Mai
- 5Department of Drug Chemistry and Technology, Istituto Pasteur Italia - Fondazione Cenci Bolognetti, La Sapienza University, P.le Aldo Moro, 5, 00185 Rome, Italy
| | - Dante Rotili
- 5Department of Drug Chemistry and Technology, Istituto Pasteur Italia - Fondazione Cenci Bolognetti, La Sapienza University, P.le Aldo Moro, 5, 00185 Rome, Italy
| | - Arianna Di Napoli
- 1Surgical Pathology Units, Department of Clinical and Molecular Medicine, Ospedale Sant'Andrea, La Sapienza University, Rome, Italy
| | - Andrea Vecchione
- 1Surgical Pathology Units, Department of Clinical and Molecular Medicine, Ospedale Sant'Andrea, La Sapienza University, Rome, Italy
| | - Cosimo De Nunzio
- 6Urology Unit, Department of Clinical and Molecular Medicine, Ospedale Sant'Andrea, La Sapienza University, Rome, Italy
| | - Patrizia Filetici
- 4Institute of Molecular Biology and Pathology-CNR, La Sapienza University of Rome, P.le, A. Moro 5, Rome, Italy
| | - Antonella Stoppacciaro
- 1Surgical Pathology Units, Department of Clinical and Molecular Medicine, Ospedale Sant'Andrea, La Sapienza University, Rome, Italy
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8
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Elvir L, Duclot F, Wang Z, Kabbaj M. Epigenetic regulation of motivated behaviors by histone deacetylase inhibitors. Neurosci Biobehav Rev 2017; 105:305-317. [PMID: 29020607 DOI: 10.1016/j.neubiorev.2017.09.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 09/26/2017] [Accepted: 09/27/2017] [Indexed: 12/15/2022]
Abstract
Growing evidence has begun to elucidate the contribution of epigenetic mechanisms in the modulation and maintenance of gene expression and behavior. Histone acetylation is one such epigenetic mechanism, which has been shown to profoundly alter gene expression and behaviors. In this review, we begin with an overview of the major epigenetic mechanisms including histones acetylation. We next focus on recent evidence about the influence of environmental stimuli on various motivated behaviors through histone acetylation and highlight how histone deacetylase inhibitors can correct some of the pathologies linked to motivated behaviors including substance abuse, feeding and social attachments. Particularly, we emphasize that the effects of histone deacetylase inhibitors on motivated behaviors are time and context-dependent.
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Affiliation(s)
- Lindsay Elvir
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Florian Duclot
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Zuoxin Wang
- Department of Psychology, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA
| | - Mohamed Kabbaj
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-1270, USA; Program of Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA.
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9
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Lin S, Sterling NA, Junker IP, Helm CT, Smith GM. Effects of αTAT1 and HDAC5 on axonal regeneration in adult neurons. PLoS One 2017; 12:e0177496. [PMID: 28505206 PMCID: PMC5432171 DOI: 10.1371/journal.pone.0177496] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/27/2017] [Indexed: 12/28/2022] Open
Abstract
The role of posttranslational modifications in axonal injury and regeneration has been widely studied but there has been little consensus over the mechanism by which each modification affects adult axonal growth. Acetylation is known to play an important role in a variety of neuronal functions and its homeostasis is controlled by two enzyme families: the Histone Deacetylases (HDACs) and Histone Acetyl Transferases (HATs). Recent studies show that HDAC5 deacetylates microtubules in the axonal cytoplasm as part of an injury-induced regeneration response, but little is known about how acetylation of microtubules plays a role. Alpha-tubulin acetyl transferase (αTAT1) is a microtubule specific acetyl transferase that binds to microtubules and directly affects microtubule stability in cells. We hypothesize that increasing tubulin acetylation may play an important role in increasing the rate of axonal growth. In this study, we infected cultured adult DRG neurons with αTAT1 and αTAT1-D157N, a catalytically inactive mutant, and HDAC5, using lentiviruses. We found that αTAT1 significantly increases tubulin acetylation in 293T cells and DRG neurons but αTAT1-D157N does not. Furthermore, in neurons infected with αTAT1, a significant increase in acetylated tubulin was detected towards the distal portion of the axon but this increase was not detected in neurons infected with αTAT1-D157N. However, we found a significant increase in axon lengths of DRG neurons after αTAT1 and αTAT1-D157N infection, but no effect on axon lengths after infection with HDAC5. Our results suggest that while αTAT1 may play a role in axon growth in vitro, the increase is not directly due to acetylation of axonal microtubules. Our results also show that HDAC5 overexpression in the axonal cytoplasm does not play a crucial role in axonal regeneration of cultured DRG neurons. We expressed these genes in DRG neurons in adult rats and performed a sciatic nerve crush. We found that axons did not regenerate any better when infected with any of the constructs compared with control animals. Thus, while αTAT1 may be important for axonal growth in vitro, neither αTAT1 nor HDAC5 had an effect in vivo on the regeneration of sciatic nerves.
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Affiliation(s)
- Shen Lin
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Noelle A. Sterling
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Ian P. Junker
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Courtney T. Helm
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - George M. Smith
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
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10
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Venkatesh I, Simpson MT, Coley DM, Blackmore MG. Epigenetic profiling reveals a developmental decrease in promoter accessibility during cortical maturation in vivo. NEUROEPIGENETICS 2016; 8:19-26. [PMID: 27990351 PMCID: PMC5159751 DOI: 10.1016/j.nepig.2016.10.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Axon regeneration in adult central nervous system (CNS) is limited in part by a developmental decline in the ability of injured neurons to re-express needed regeneration associated genes (RAGs). Adult CNS neurons may lack appropriate pro-regenerative transcription factors, or may display chromatin structure that restricts transcriptional access to RAGs. Here we performed epigenetic profiling around the promoter regions of key RAGs, and found progressive restriction across a time course of cortical maturation. These data identify a potential intrinsic constraint to axon growth in adult CNS neurons. Neurite outgrowth from cultured postnatal cortical neurons, however, proved insensitive to treatments that improve axon growth in other cell types, including combinatorial overexpression of AP1 factors, overexpression of histone acetyltransferases, and pharmacological inhibitors of histone deacetylases. This insensitivity could be due to intermediate chromatin closure at the time of culture, and highlights important differences in cell culture models used to test potential pro-regenerative interventions.
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Affiliation(s)
| | | | - Denise M. Coley
- Department of Biomedical Sciences, Marquette University, 53201
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11
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Chen J, Shifman MI. The expression of histone deacetylases and the regenerative abilities of spinal-projecting neurons after injury. Neural Regen Res 2016; 11:1577-1578. [PMID: 27904485 PMCID: PMC5116833 DOI: 10.4103/1673-5374.193233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Jie Chen
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
| | - Michael I Shifman
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA; Department of Neuroscience, Temple University School of Medicine, Philadelphia, PA, USA
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12
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Lin S, Smith GM. Acetylation as a mechanism that regulates axonal regeneration. Neural Regen Res 2015; 10:1034-6. [PMID: 26330814 PMCID: PMC4541222 DOI: 10.4103/1673-5374.160066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2015] [Indexed: 12/15/2022] Open
Affiliation(s)
- Shen Lin
- Shriners Hospitals for Pediatric Research Center, Department of Neuroscience, Temple University, Philadelphia, PA, USA
| | - George M Smith
- Shriners Hospitals for Pediatric Research Center, Department of Neuroscience, Temple University, Philadelphia, PA, USA
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