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Palmisano I, Liu T, Gao W, Zhou L, Merkenschlager M, Müller F, Chadwick J, Rivolta RT, Kong G, King JW, Al-Jibury E, Yan Y, Carlino A, Collison B, De Vitis E, Gongala S, De Virgiliis F, Wang Z, Giovanni SD. Three-dimensional chromatin mapping of sensory neurons reveals that cohesin-dependent genomic domains are required for axonal regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.09.597974. [PMID: 38895406 PMCID: PMC11185766 DOI: 10.1101/2024.06.09.597974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The in vivo three-dimensional genomic architecture of adult mature neurons at homeostasis and after medically relevant perturbations such as axonal injury remains elusive. Here we address this knowledge gap by mapping the three-dimensional chromatin architecture and gene expression programme at homeostasis and after sciatic nerve injury in wild-type and cohesin-deficient mouse sensory dorsal root ganglia neurons via combinatorial Hi-C and RNA-seq. We find that cohesin is required for the full induction of the regenerative transcriptional program, by organising 3D genomic domains required for the activation of regenerative genes. Importantly, loss of cohesin results in disruption of chromatin architecture at regenerative genes and severely impaired nerve regeneration. Together, these data provide an original three-dimensional chromatin map of adult sensory neurons in vivo and demonstrate a role for cohesin-dependent chromatin interactions in neuronal regeneration.
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Zhou X, He Y, Quan H, Yang J, Li S, Jiang Y, Li J, Yuan X. Exposure to nicotine regulates prostaglandin E2 secretion and autophagy of granulosa cells to retard follicular maturation in mammals. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 277:116358. [PMID: 38653025 DOI: 10.1016/j.ecoenv.2024.116358] [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: 01/25/2024] [Revised: 04/09/2024] [Accepted: 04/19/2024] [Indexed: 04/25/2024]
Abstract
Exposure to nicotine by cigarette smoking have shown strongly defectives on the physiological function of ovaries, which in turn leads to disorders of fertility in women. However, the potential molecular mechanisms remain to be elucidated. In this study, we notably found that nicotine was likely to specifically raise the expression of histone deacetylase 3 (HDAC3) to promote the apoptosis and autophagy of granulosa cells (GCs) and block follicular maturation. Moreover, prostaglandin E2 (PGE2) inhibited the apoptosis of GCs and facilitated follicular maturation, and nicotine appeared to inhibit PGE2 secretion by freezing the expression of cyclooxygenase 1 (COX1), which was the rate-limiting and essential enzyme for PGE2 synthesis. Epigenetically, the nicotine was observed to diminish the histone H3 lysine 9 acetylation (H3K9ac) level and compact the chromatin accessibility in -1776/-1499 bp region of COX1 by evoking the expression of HDAC3, with the deactivated Cas9-HDAC3/sgRNA system. Mechanistically, the COX1 protein was found to pick up and degrade the autophagy related protein beclin 1 (BECN1) to control the autophagy of GCs. These results provided a potential new molecular therapy to recover the damage of female fertility induced by nicotine from cigarette smoking.
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Affiliation(s)
- Xiaofeng Zhou
- Guangdong Laboratory of Lingnan Modern Agriculture, National Engineering Research Center for Breeding Swine Industry, State Key Laboratory of Swine and Poultry Breeding Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yingting He
- Guangdong Laboratory of Lingnan Modern Agriculture, National Engineering Research Center for Breeding Swine Industry, State Key Laboratory of Swine and Poultry Breeding Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hongyan Quan
- Guangdong Laboratory of Lingnan Modern Agriculture, National Engineering Research Center for Breeding Swine Industry, State Key Laboratory of Swine and Poultry Breeding Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jinghao Yang
- Guangdong Laboratory of Lingnan Modern Agriculture, National Engineering Research Center for Breeding Swine Industry, State Key Laboratory of Swine and Poultry Breeding Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Shuo Li
- Guangdong Laboratory of Lingnan Modern Agriculture, National Engineering Research Center for Breeding Swine Industry, State Key Laboratory of Swine and Poultry Breeding Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yao Jiang
- School of Medical, Molecular and Forensic Sciences, Murdoch University, Murdoch, WA 6149, Australia; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
| | - Jiaqi Li
- Guangdong Laboratory of Lingnan Modern Agriculture, National Engineering Research Center for Breeding Swine Industry, State Key Laboratory of Swine and Poultry Breeding Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
| | - Xiaolong Yuan
- Guangdong Laboratory of Lingnan Modern Agriculture, National Engineering Research Center for Breeding Swine Industry, State Key Laboratory of Swine and Poultry Breeding Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
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Smies CW, Bellfy L, Wright DS, Bennetts SS, Urban MW, Brunswick CA, Shu G, Kwapis JL. Pharmacological HDAC3 inhibition alters memory updating in young and old mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593015. [PMID: 38766057 PMCID: PMC11100699 DOI: 10.1101/2024.05.08.593015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Long-term memories are not stored in a stable state but must be flexible and dynamic to maintain relevance in response to new information. Existing memories are thought to be updated through the process of reconsolidation, in which memory retrieval initiates destabilization and updating to incorporate new information. Memory updating is impaired in old age, yet little is known about the mechanisms that go awry. One potential mechanism is the repressive histone deacetylase 3 (HDAC3), which is a powerful negative regulator of memory formation that contributes to age-related impairments in memory formation. Here, we tested whether HDAC3 also contributes to age-related impairments in memory updating using the Objects in Updated Locations (OUL) paradigm. We show that blocking HDAC3 immediately after updating with the pharmacological inhibitor RGFP966 ameliorated age-related impairments in memory updating in 18-m.o. mice. Surprisingly, we found that post-update HDAC3 inhibition in young (3-m.o.) mice had no effect on memory updating but instead impaired memory for the original information, suggesting that the original and updated information may compete for expression at test and HDAC3 helps regulate which information is expressed. To test this idea, we next assessed whether HDAC3 inhibition would improve memory updating in young mice given a weak, subthreshold update. Consistent with our hypothesis, we found that HDAC3 blockade strengthened the subthreshold update without impairing memory for the original information, enabling balanced expression of the original and updated information. Together, this research suggests that HDAC3 may contribute to age-related impairments in memory updating and may regulate the strength of a memory update in young mice, shifting the balance between the original and updated information at test.
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Zhao Q, Jiang C, Zhao L, Dai X, Yi S. Unleashing Axonal Regeneration Capacities: Neuronal and Non-neuronal Changes After Injuries to Dorsal Root Ganglion Neuron Central and Peripheral Axonal Branches. Mol Neurobiol 2024; 61:423-433. [PMID: 37620687 DOI: 10.1007/s12035-023-03590-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023]
Abstract
Peripheral nerves obtain remarkable regenerative capacity while central nerves can hardly regenerate following nerve injury. Sensory neurons in the dorsal root ganglion (DRG) are widely used to decipher the dissimilarity between central and peripheral axonal regeneration as axons of DRG neurons bifurcate into the regeneration-incompetent central projections and the regeneration-competent peripheral projections. A conditioning peripheral branch injury facilitates central axonal regeneration and enables the growth and elongation of central axons. Peripheral axonal injury stimulates neuronal calcium influx, alters the start-point chromatin states, increases chromatin accessibility, upregulates the expressions of regeneration-promoting genes and the synthesis of proteins, and supports axonal regeneration. Following central axonal injury, the responses of DRG neurons are modest, resulting in poor intrinsic growth ability. Some non-neuronal cells in DRGs, for instance satellite glial cells, also exhibit diminished injury responses to central axon injury as compared with peripheral axon injury. Moreover, DRG central and peripheral axonal branches are respectively surrounded by inhibitory glial scars generated by central glial cells and a permissive microenvironment generated by Schwann cells and macrophages. The aim of this review is to look at changes of DRG neurons and non-neuronal cells after peripheral and central axon injuries and summarize the contributing roles of both neuronal intrinsic regenerative capacities and surrounding microenvironments in axonal regeneration.
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Affiliation(s)
- Qian Zhao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu, China
| | - Chunyi Jiang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu, China
- Department of Pathology, Nantong University Affiliated Hospital, Nantong, Jiangsu, China
| | - Li Zhao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu, China
| | - Xiu Dai
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu, China.
| | - Sheng Yi
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu, China.
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Graves LY, Keane KF, Taylor JY, Wang TF, Saligan L, Bogie KM. Subacute and Chronic Spinal Cord Injury: A Scoping Review of Epigenetics and Secondary Health Conditions. Epigenet Insights 2023; 16:25168657231205679. [PMID: 37900668 PMCID: PMC10612389 DOI: 10.1177/25168657231205679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 09/11/2023] [Indexed: 10/31/2023] Open
Abstract
Background Epigenetics studies the impact of environmental and behavioral factors on stable phenotypic changes; however, the state of the science examining epigenomic mechanisms of regulation related to secondary health conditions (SHCs) and neuroepigenetics in chronic spinal cord injury (SCI) remain markedly underdeveloped. Objective This scoping review seeks to understand the state of the science in epigenetics and secondary complications following SCI. Methods A literature search was conducted, yielding 277 articles. The inclusion criteria were articles (1) investigating SCI and (2) examining epigenetic regulation as part of the study methodology. A total of 23 articles were selected for final inclusion. Results Of the 23 articles 52% focused on histone modification, while 26% focused on DNA methylation. One study had a human sample, while the majority sampled rats and mice. Primarily, studies examined regeneration, with only one study looking at clinically relevant SHC, such as neuropathic pain. Discussion The findings of this scoping review offer exciting insights into epigenetic and neuroepigenetic application in SCI research. Several key genes, proteins, and pathways emerged across studies, suggesting the critical role of epigenetic regulation in biological processes. This review reinforced the dearth of studies that leverage epigenetic methods to identify prognostic biomarkers in SHCs. Preclinical models of SCI were genotypically and phenotypically similar, which is not reflective of the heterogeneity found in the clinical population of persons with SCI. There is a need to develop better preclinical models and more studies that examine the role of genomics and epigenomics in understanding the diverse health outcomes associated with traumatic SCI.
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Affiliation(s)
- Letitia Y Graves
- School of Nursing, University of Texas Medical Branch, Galveston, TX, USA
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA
| | - Kayla F Keane
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Jacquelyn Y Taylor
- Columbia School of Nursing and Center for Research on People of Color, New York, NY, USA
| | - Tzu-fang Wang
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leorey Saligan
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Kath M Bogie
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA
- Case Western Reserve University, Cleveland, OH, USA
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Wang C, Shen D, Hu Y, Chen J, Liu J, Huang Y, Yu X, Chu H, Zhang C, Yin L, Liu Y, Ma H. Selective Targeting of Class I HDAC Reduces Microglial Inflammation in the Entorhinal Cortex of Young APP/PS1 Mice. Int J Mol Sci 2023; 24:4805. [PMID: 36902234 PMCID: PMC10003411 DOI: 10.3390/ijms24054805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
BG45 is a class Ⅰ histone deacetylase inhibitor (HDACI) with selectivity for HDAC3. Our previous study demonstrated that BG45 can upregulate the expression of synaptic proteins and reduce the loss of neurons in the hippocampus of APPswe/PS1dE9 (APP/PS1) transgenic mice (Tg). The entorhinal cortex is a pivotal region that, along with the hippocampus, plays a critical role in memory in the Alzheimer's disease (AD) pathology process. In this study, we focused on the inflammatory changes in the entorhinal cortex of APP/PS1 mice and further explored the therapeutic effects of BG45 on the pathologies. The APP/PS1 mice were randomly divided into the transgenic group without BG45 (Tg group) and the BG45-treated groups. The BG45-treated groups were treated with BG45 at 2 months (2 m group), at 6 months (6 m group), or twice at 2 and 6 months (2 and 6 m group). The wild-type mice group (Wt group) served as the control. All mice were killed within 24 h after the last injection at 6 months. The results showed that amyloid-β (Aβ) deposition and IBA1-positive microglia and GFAP-positive astrocytes in the entorhinal cortex of the APP/PS1 mice progressively increased over time from 3 to 8 months of age. When the APP/PS1 mice were treated with BG45, the level of H3K9K14/H3 acetylation was improved and the expression of histonedeacetylase1, histonedeacetylase2, and histonedeacetylase3 was inhibited, especially in the 2 and 6 m group. BG45 alleviated Aβ deposition and reduced the phosphorylation level of tau protein. The number of IBA1-positive microglia and GFAP-positive astrocytes decreased with BG45 treatment, and the effect was more significant in the 2 and 6 m group. Meanwhile, the expression of synaptic proteins synaptophysin, postsynaptic density protein 95, and spinophilin was upregulated and the degeneration of neurons was alleviated. Moreover, BG45 reduced the gene expression of inflammatory cytokines interleukin-1β and tumor necrosis factor-α. Closely related to the CREB/BDNF/NF-kB pathway, the expression of p-CREB/CREB, BDNF, and TrkB was increased in all BG45 administered groups compared with the Tg group. However, the levels of p-NF-kB/NF-kB in the BG45 treatment groups were reduced. Therefore, we deduced that BG45 is a potential drug for AD by alleviating inflammation and regulating the CREB/BDNF/NF-kB pathway, and the early, repeated administration of BG45 can play a more effective role.
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Affiliation(s)
- Chunyang Wang
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Di Shen
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Yingqiu Hu
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Jie Chen
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Jingyun Liu
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Yufei Huang
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Xuebin Yu
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Haiying Chu
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Chenghong Zhang
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Liangwei Yin
- Department of Oncology, Dalian Municipal Central Hospital, Dalian 116089, China
| | - Yi Liu
- Department of Neurology, Dalian Municipal Central Hospital, Dalian 116089, China
| | - Haiying Ma
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
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Zheng B, Tuszynski MH. Regulation of axonal regeneration after mammalian spinal cord injury. Nat Rev Mol Cell Biol 2023; 24:396-413. [PMID: 36604586 DOI: 10.1038/s41580-022-00562-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2022] [Indexed: 01/06/2023]
Abstract
One hundred years ago, Ramón y Cajal, considered by many as the founder of modern neuroscience, stated that neurons of the adult central nervous system (CNS) are incapable of regenerating. Yet, recent years have seen a tremendous expansion of knowledge in the molecular control of axon regeneration after CNS injury. We now understand that regeneration in the adult CNS is limited by (1) a failure to form cellular or molecular substrates for axon attachment and elongation through the lesion site; (2) environmental factors, including inhibitors of axon growth associated with myelin and the extracellular matrix; (3) astrocyte responses, which can both limit and support axon growth; and (4) intraneuronal mechanisms controlling the establishment of an active cellular growth programme. We discuss these topics together with newly emerging hypotheses, including the surprising finding from transcriptomic analyses of the corticospinal system in mice that neurons revert to an embryonic state after spinal cord injury, which can be sustained to promote regeneration with neural stem cell transplantation. These gains in knowledge are steadily advancing efforts to develop effective treatment strategies for spinal cord injury in humans.
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Affiliation(s)
- Binhai Zheng
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,VA San Diego Research Service, San Diego, CA, USA.
| | - Mark H Tuszynski
- Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,VA San Diego Research Service, San Diego, CA, USA.
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Müller F, Chadwick JS, Di Giovanni S, Palmisano I. Epigenomic Profiling of Dorsal Root Ganglia upon Regenerative and Non-regenerative Axonal Injury. Methods Mol Biol 2023; 2636:101-144. [PMID: 36881298 DOI: 10.1007/978-1-0716-3012-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
RNA sequencing (RNA-seq), chromatin immunoprecipitation sequencing (ChIP-seq), and assay for transposase-accessible chromatin sequencing (ATAC-seq) are genome-wide techniques that provide information relative to gene expression, chromatin binding sites, and chromatin accessibility, respectively. Here we describe RNA-seq, H3K9ac, H3K27ac and H3K27me3 ChIP-seq, and ATAC-seq in dorsal root ganglia (DRG) after sciatic nerve or dorsal column axotomy, to characterize the transcriptional and epigenetic signatures of DRG upon regenerative vs non-regenerative axonal lesion.
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Affiliation(s)
- Franziska Müller
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Jessica S Chadwick
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Simone Di Giovanni
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Ilaria Palmisano
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK.
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Zhang J, Chen SR, Zhou MH, Jin D, Chen H, Wang L, DePinho RA, Pan HL. HDAC2 in Primary Sensory Neurons Constitutively Restrains Chronic Pain by Repressing α2δ-1 Expression and Associated NMDA Receptor Activity. J Neurosci 2022; 42:8918-8935. [PMID: 36257688 PMCID: PMC9732832 DOI: 10.1523/jneurosci.0735-22.2022] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 01/05/2023] Open
Abstract
α2δ-1 (encoded by the Cacna2d1 gene) is a newly discovered NMDA receptor-interacting protein and is the therapeutic target of gabapentinoids (e.g., gabapentin and pregabalin) frequently used for treating patients with neuropathic pain. Nerve injury causes sustained α2δ-1 upregulation in the dorsal root ganglion (DRG), which promotes NMDA receptor synaptic trafficking and activation in the spinal dorsal horn, a hallmark of chronic neuropathic pain. However, little is known about how nerve injury initiates and maintains the high expression level of α2δ-1 to sustain chronic pain. Here, we show that nerve injury caused histone hyperacetylation and diminished enrichment of histone deacetylase-2 (HDAC2), but not HDAC3, at the Cacna2d1 promoter in the DRG. Strikingly, Hdac2 knockdown or conditional knockout in DRG neurons in male and female mice consistently induced long-lasting mechanical pain hypersensitivity, which was readily reversed by blocking NMDA receptors, inhibiting α2δ-1 with gabapentin or disrupting the α2δ-1-NMDA receptor interaction at the spinal cord level. Hdac2 deletion in DRG neurons increased histone acetylation levels at the Cacna2d1 promoter, upregulated α2δ-1 in the DRG, and potentiated α2δ-1-dependent NMDA receptor activity at primary afferent central terminals in the spinal dorsal horn. Correspondingly, Hdac2 knockdown-induced pain hypersensitivity was blunted in Cacna2d1 knockout mice. Thus, our findings reveal that HDAC2 functions as a pivotal transcriptional repressor of neuropathic pain via constitutively suppressing α2δ-1 expression and ensuing presynaptic NMDA receptor activity in the spinal cord. HDAC2 enrichment levels at the Cacna2d1 promoter in DRG neurons constitute a unique epigenetic mechanism that governs acute-to-chronic pain transition.SIGNIFICANCE STATEMENT Excess α2δ-1 proteins produced after nerve injury directly interact with glutamate NMDA receptors to potentiate synaptic NMDA receptor activity in the spinal cord, a prominent mechanism of nerve pain. Because α2δ-1 upregulation after nerve injury is long lasting, gabapentinoids relieve pain symptoms only temporarily. Our study demonstrates for the first time the unexpected role of intrinsic HDAC2 activity at the α2δ-1 gene promoter in limiting α2δ-1 gene transcription, NMDA receptor-dependent synaptic plasticity, and chronic pain development after nerve injury. These findings challenge the prevailing view about the role of general HDAC activity in promoting chronic pain. Restoring the repressive HDAC2 function and/or reducing histone acetylation at the α2δ-1 gene promoter in primary sensory neurons could lead to long-lasting relief of nerve pain.
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Affiliation(s)
- Jixiang Zhang
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Shao-Rui Chen
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Meng-Hua Zhou
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Daozhong Jin
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Hong Chen
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Li Wang
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Ronald A DePinho
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Hui-Lin Pan
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
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10
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Müller F, De Virgiliis F, Kong G, Zhou L, Serger E, Chadwick J, Sanchez-Vassopoulos A, Singh AK, Eswaramoorthy M, Kundu TK, Di Giovanni S. CBP/p300 activation promotes axon growth, sprouting, and synaptic plasticity in chronic experimental spinal cord injury with severe disability. PLoS Biol 2022; 20:e3001310. [PMID: 36126035 PMCID: PMC9488786 DOI: 10.1371/journal.pbio.3001310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/12/2022] [Indexed: 11/18/2022] Open
Abstract
The interruption of spinal circuitry following spinal cord injury (SCI) disrupts neural activity and is followed by a failure to mount an effective regenerative response resulting in permanent neurological disability. Functional recovery requires the enhancement of axonal and synaptic plasticity of spared as well as injured fibres, which need to sprout and/or regenerate to form new connections. Here, we have investigated whether the epigenetic stimulation of the regenerative gene expression program can overcome the current inability to promote neurological recovery in chronic SCI with severe disability. We delivered the CBP/p300 activator CSP-TTK21 or vehicle CSP weekly between week 12 and 22 following a transection model of SCI in mice housed in an enriched environment. Data analysis showed that CSP-TTK21 enhanced classical regenerative signalling in dorsal root ganglia sensory but not cortical motor neurons, stimulated motor and sensory axon growth, sprouting, and synaptic plasticity, but failed to promote neurological sensorimotor recovery. This work provides direct evidence that clinically suitable pharmacological CBP/p300 activation can promote the expression of regeneration-associated genes and axonal growth in a chronic SCI with severe neurological disability.
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Affiliation(s)
- Franziska Müller
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, London, United Kingdom
| | - Francesco De Virgiliis
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, London, United Kingdom
| | - Guiping Kong
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, London, United Kingdom
| | - Luming Zhou
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, London, United Kingdom
| | - Elisabeth Serger
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, London, United Kingdom
| | - Jessica Chadwick
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, London, United Kingdom
| | | | - Akash Kumar Singh
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, JNCASR, Bangalore, India
| | | | - Tapas K. Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, JNCASR, Bangalore, India
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Simone Di Giovanni
- Department of Brain Sciences, Division of Neuroscience, Imperial College London, London, United Kingdom
- * E-mail:
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11
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Avraham O, Le J, Leahy K, Li T, Zhao G, Cavalli V. Analysis of neuronal injury transcriptional response identifies CTCF and YY1 as co-operating factors regulating axon regeneration. Front Mol Neurosci 2022; 15:967472. [PMID: 36081575 PMCID: PMC9446241 DOI: 10.3389/fnmol.2022.967472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
Injured sensory neurons activate a transcriptional program necessary for robust axon regeneration and eventual target reinnervation. Understanding the transcriptional regulators that govern this axon regenerative response may guide therapeutic strategies to promote axon regeneration in the injured nervous system. Here, we used cultured dorsal root ganglia neurons to identify pro-regenerative transcription factors. Using RNA sequencing, we first characterized this neuronal culture and determined that embryonic day 13.5 DRG (eDRG) neurons cultured for 7 days are similar to e15.5 DRG neurons in vivo and that all neuronal subtypes are represented. This eDRG neuronal culture does not contain other non-neuronal cell types. Next, we performed RNA sequencing at different time points after in vitro axotomy. Analysis of differentially expressed genes revealed upregulation of known regeneration associated transcription factors, including Jun, Atf3 and Rest, paralleling the axon injury response in vivo. Analysis of transcription factor binding sites in differentially expressed genes revealed other known transcription factors promoting axon regeneration, such as Myc, Hif1α, Pparγ, Ascl1a, Srf, and Ctcf, as well as other transcription factors not yet characterized in axon regeneration. We next tested if overexpression of novel candidate transcription factors alone or in combination promotes axon regeneration in vitro. Our results demonstrate that expression of Ctcf with Yy1 or E2f2 enhances in vitro axon regeneration. Our analysis highlights that transcription factor interaction and chromatin architecture play important roles as a regulator of axon regeneration.
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Affiliation(s)
- Oshri Avraham
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Jimmy Le
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Kathleen Leahy
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Tiandao Li
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
- Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Guoyan Zhao
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
- Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, United States
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, United States
- *Correspondence: Valeria Cavalli,
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12
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Gomez-Sanchez JA, Patel N, Martirena F, Fazal SV, Mutschler C, Cabedo H. Emerging Role of HDACs in Regeneration and Ageing in the Peripheral Nervous System: Repair Schwann Cells as Pivotal Targets. Int J Mol Sci 2022; 23:ijms23062996. [PMID: 35328416 PMCID: PMC8951080 DOI: 10.3390/ijms23062996] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 02/07/2023] Open
Abstract
The peripheral nervous system (PNS) has a remarkable regenerative capacity in comparison to the central nervous system (CNS), a phenomenon that is impaired during ageing. The ability of PNS axons to regenerate after injury is due to Schwann cells (SC) being reprogrammed into a repair phenotype called Repair Schwann cells. These repair SCs are crucial for supporting axonal growth after injury, myelin degradation in a process known as myelinophagy, neurotropic factor secretion, and axonal growth guidance through the formation of Büngner bands. After regeneration, repair SCs can remyelinate newly regenerated axons and support nonmyelinated axons. Increasing evidence points to an epigenetic component in the regulation of repair SC gene expression changes, which is necessary for SC reprogramming and regeneration. One of these epigenetic regulations is histone acetylation by histone acetyl transferases (HATs) or histone deacetylation by histone deacetylases (HDACs). In this review, we have focused particularly on three HDAC classes (I, II, and IV) that are Zn2+-dependent deacetylases. These HDACs are important in repair SC biology and remyelination after PNS injury. Another key aspect explored in this review is HDAC genetic compensation in SCs and novel HDAC inhibitors that are being studied to improve nerve regeneration.
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Affiliation(s)
- Jose A. Gomez-Sanchez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (N.P.); (H.C.)
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), 03010 Alicante, Spain
- Correspondence: ; Tel.: +34-965-919-594
| | - Nikiben Patel
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (N.P.); (H.C.)
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), 03010 Alicante, Spain
| | - Fernanda Martirena
- Department of Hematology, General University Hospital of Elda, 03600 Elda, Spain;
| | - Shaline V. Fazal
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK; (S.V.F.); (C.M.)
- Wellcome—MRC Cambridge Stem Cell Institute, Puddicombe Way, Cambridge CB2 0AW, UK
| | - Clara Mutschler
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK; (S.V.F.); (C.M.)
| | - Hugo Cabedo
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (N.P.); (H.C.)
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), 03010 Alicante, Spain
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13
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Kong G, Zhou L, Freiwald A, Shkura K, Di Giovanni S. Purification of mouse axoplasmic proteins from dorsal root ganglia nerves for proteomics analysis. STAR Protoc 2022; 3:101166. [PMID: 35535163 PMCID: PMC9076968 DOI: 10.1016/j.xpro.2022.101166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The study of neuronal signaling ex vivo requires the identification of the proteins that are represented within the neuronal axoplasm. Here, we describe a detailed protocol to isolate the axoplasm of peripheral and central axonal branches of sciatic dorsal root ganglia neurons in mice. The axoplasm is separated by 2D gel and digestion followed by proteomics analysis with MS/MS-LC. This protocol can be applied to dissect the axoplasmic protein expression signatures before and after a sciatic nerve or a spinal cord injury. For complete details on the use and execution of this protocol, please refer to Kong et al. (2020). Detection of axoplasmic protein expression in the mouse after nerve injury Axoplasm protein extraction and concentration from the sciatic nerve and dorsal roots Mass spectrometry analysis of axoplasmic protein expression
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14
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Lowell JA, O’Neill N, Danzi MC, Al-Ali H, Bixby JL, Lemmon VP. Phenotypic Screening Following Transcriptomic Deconvolution to Identify Transcription Factors Mediating Axon Growth Induced by a Kinase Inhibitor. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2021; 26:1337-1354. [PMID: 34218704 PMCID: PMC10509783 DOI: 10.1177/24725552211026270] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
After injury to the central nervous system (CNS), both neuron-intrinsic limitations on regenerative responses and inhibitory factors in the injured CNS environment restrict regenerative axon growth. Instances of successful axon regrowth offer opportunities to identify features that differentiate these situations from that of the normal adult CNS. One such opportunity is provided by the kinase inhibitor RO48, which dramatically enhances neurite outgrowth of neurons in vitro and substantially increased contralateral sprouting of corticospinal tract neurons when infused intraventricularly following unilateral pyramidotomy. The authors present here a transcriptomic deconvolution of RO48-associated axon growth, with the goal of identifying transcriptional regulators associated with axon growth in the CNS. Through the use of RNA sequencing (RNA-seq) and transcription factor binding site enrichment analysis, the authors identified a list of transcription factors putatively driving differential gene expression during RO48-induced neurite outgrowth of rat hippocampal neurons in vitro. The 82 transcription factor motifs identified in this way included some with known association to axon growth regulation, such as Jun, Klf4, Myc, Atf4, Stat3, and Nfatc2, and many with no known association to axon growth. A phenotypic loss-of-function screen was carried out to evaluate these transcription factors for their roles in neurite outgrowth; this screen identified several potential outgrowth regulators. Subsequent validation suggests that the Forkhead box (Fox) family transcription factor Foxp2 restricts neurite outgrowth, while FoxO subfamily members Foxo1 and Foxo3a promote neurite outgrowth. The authors' combined transcriptomic-phenotypic screening strategy therefore allowed identification of novel transcriptional regulators of neurite outgrowth downstream of a multitarget kinase inhibitor.
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Affiliation(s)
- Jeffrey A. Lowell
- Miami Project to Cure Paralysis and University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nicholas O’Neill
- Miami Project to Cure Paralysis and University of Miami Miller School of Medicine, Miami, FL, USA
| | - Matt C. Danzi
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Hassan Al-Ali
- Miami Project to Cure Paralysis and University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Medicine and Peggy & Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL, USA
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - John L. Bixby
- Miami Project to Cure Paralysis and University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Vance P. Lemmon
- Miami Project to Cure Paralysis and University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
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15
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Pita-Thomas W, Gonçalves TM, Kumar A, Zhao G, Cavalli V. Genome-wide chromatin accessibility analyses provide a map for enhancing optic nerve regeneration. Sci Rep 2021; 11:14924. [PMID: 34290335 PMCID: PMC8295311 DOI: 10.1038/s41598-021-94341-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/05/2021] [Indexed: 11/21/2022] Open
Abstract
Retinal Ganglion Cells (RGCs) lose their ability to grow axons during development. Adult RGCs thus fail to regenerate their axons after injury, leading to vision loss. To uncover mechanisms that promote regeneration of RGC axons, we identified transcription factors (TF) and open chromatin regions that are enriched in rat embryonic RGCs (high axon growth capacity) compared to postnatal RGCs (low axon growth capacity). We found that developmental stage-specific gene expression changes correlated with changes in promoter chromatin accessibility. Binding motifs for TFs such as CREB, CTCF, JUN and YY1 were enriched in the regions of the chromatin that were more accessible in embryonic RGCs. Proteomic analysis of purified rat RGC nuclei confirmed the expression of TFs with potential role in axon growth such as CREB, CTCF, YY1, and JUND. The CREB/ATF binding motif was widespread at the open chromatin region of known pro-regenerative TFs, supporting a role of CREB in regulating axon regeneration. Consistently, overexpression of CREB fused to the VP64 transactivation domain in mouse RGCs promoted axon regeneration after optic nerve injury. Our study provides a map of the chromatin accessibility during RGC development and highlights that TF associated with developmental axon growth can stimulate axon regeneration in mature RGC.
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Affiliation(s)
- Wolfgang Pita-Thomas
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, 63110, USA
| | | | - Ajeet Kumar
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Guoyan Zhao
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, 63110, USA. .,Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA.
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, 63110, USA. .,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA. .,Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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16
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Mazzocchi M, Goulding SR, Wyatt SL, Collins LM, Sullivan AM, O'Keeffe GW. LMK235, a small molecule inhibitor of HDAC4/5, protects dopaminergic neurons against neurotoxin- and α-synuclein-induced degeneration in cellular models of Parkinson's disease. Mol Cell Neurosci 2021; 115:103642. [PMID: 34119632 DOI: 10.1016/j.mcn.2021.103642] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 01/24/2023] Open
Abstract
Epigenetic modifications in neurodegenerative disease are under investigation for their roles in disease progression. Alterations in acetylation rates of certain Parkinson's disease (PD)-linked genes have been associated with the pathological progression of this disorder. In light of this, and given the lack of disease-modifying therapies for PD, HDAC inhibitors (HDIs) are under consideration as potential pharmacological agents. The neuroprotective effects of pan-HDACs and some class-specific inhibitors have been tested in in vivo and in vitro models of PD, with varying outcomes. Here we used gene co-expression analysis to identify HDACs that are associated with human dopaminergic (DA) neuron development. We identified HDAC3, HDAC5, HDAC6 and HDAC9 as being highly correlated with the DA markers, SLC6A3 and NR4A2. RT-qPCR revealed that mRNA expression of these HDACs exhibited similar temporal profiles during embryonic mouse midbrain DA (mDA) neuron development. We tested the neuroprotective potential of a number of class-specific small molecule HDIs on human SH-SY5Y cells, using neurite growth as a phenotypic readout of neurotrophic action. Neither the class I-specific HDIs, RGFP109 and RGFP966, nor the HDAC6 inhibitor ACY1215, had significant effects on neurite outgrowth. However, the class IIa HDI, LMK235 (a HDAC4/5 inhibitor), significantly increased histone acetylation and neurite outgrowth. We found that LMK235 increased BMP-Smad-dependent transcription in SH-SY5Y cells and that this was required for its neurite growth-promoting effects on SH-SY5Y cells and on DA neurons in primary cultures of embryonic day (E) 14 rat ventral mesencephalon (VM). These effects were also seen in SH-SY5Y cells transfected with HDAC5 siRNA. Furthermore, LMK235 treatment exerted neuroprotective effects against degeneration induced by the DA neurotoxin 1-methyl-4-phenylpyridinium (MPP+), in both SH-SY5Y cells and cultured DA neurons. Treatment with LMK235 was also neuroprotective against axonal degeneration induced by overexpression of wild-type (WT) or A53T mutant α-synuclein in both SH-SY5Y cells and primary cultures of DA neurons. In summary, these data show the neuroprotective potential of the class IIa HDI, LMK235, in cell models of relevance to PD.
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Affiliation(s)
- Martina Mazzocchi
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland
| | - Susan R Goulding
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland
| | - Sean L Wyatt
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Louise M Collins
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland; Department of Physiology, UCC, Cork, Ireland
| | - Aideen M Sullivan
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland; APC Microbiome Ireland, UCC, Cork, Ireland.
| | - Gerard W O'Keeffe
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland; APC Microbiome Ireland, UCC, Cork, Ireland.
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17
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The Life of a Trailing Spouse. J Neurosci 2021; 41:3-10. [PMID: 33408132 DOI: 10.1523/jneurosci.2874-20.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 11/21/2022] Open
Abstract
In 1981, I published a paper in the first issue of the Journal of Neuroscience with my postdoctoral mentor, Alan Pearlman. It reported a quantitative analysis of the receptive field properties of neurons in reeler mouse visual cortex and the surprising conclusion that although the neuronal somas were strikingly malpositioned, their receptive fields were unchanged. This suggested that in mouse cortex at least, neuronal circuits have very robust systems in place to ensure the proper formation of connections. This had the unintended consequence of transforming me from an electrophysiologist into a cellular and molecular neuroscientist who studied cell adhesion molecules and the molecular mechanisms they use to regulate axon growth. It took me a surprisingly long time to appreciate that your science is driven by the people around you and by the technologies that are locally available. As a professional puzzler, I like all different kinds of puzzles, but the most fun puzzles involve playing with other puzzlers. This is my story of learning how to find like-minded puzzlers to solve riddles about axon growth and regeneration.
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18
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HDAC3 Activity within the Nucleus Accumbens Regulates Cocaine-Induced Plasticity and Behavior in a Cell-Type-Specific Manner. J Neurosci 2021; 41:2814-2827. [PMID: 33602824 PMCID: PMC8018887 DOI: 10.1523/jneurosci.2829-20.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/04/2021] [Accepted: 02/03/2021] [Indexed: 01/19/2023] Open
Abstract
Epigenetic mechanisms regulate processes of neuroplasticity critical to cocaine-induced behaviors. This includes the Class I histone deacetylase (HDAC) HDAC3, known to act as a negative regulator of cocaine-associated memory formation within the nucleus accumbens (NAc). Despite this, it remains unknown how cocaine alters HDAC3-dependent mechanisms. Here, we profiled HDAC3 expression and activity in total NAc mouse tissue following cocaine exposure. Although chronic cocaine did not affect expression of Hdac3 within the NAc, chronic cocaine did affect promoter-specific changes in HDAC3 and H4K8Ac occupancy. These changes in promoter occupancy correlated with cocaine-induced changes in expression of plasticity-related genes. To causally determine whether cocaine-induced plasticity is mediated by HDAC3's deacetylase activity, we overexpressed a deacetylase-dead HDAC3 point mutant (HDAC3-Y298H-v5) within the NAc of adult male mice. We found that disrupting HDAC3's enzymatic activity altered selective changes in gene expression and synaptic plasticity following cocaine exposure, despite having no effects on cocaine-induced behaviors. In further assessing HDAC3's role within the NAc, we observed that chronic cocaine increases Hdac3 expression in Drd1 but not Drd2-cells of the NAc. Moreover, we discovered that HDAC3 acts selectively within D1R cell-types to regulate cocaine-associated memory formation and cocaine-seeking. Overall, these results suggest that cocaine induces cell-type-specific changes in epigenetic mechanisms to promote plasticity important for driving cocaine-related behaviors. SIGNIFICANCE STATEMENT Drugs of abuse alter molecular mechanisms throughout the reward circuitry that can lead to persistent drug-associated behaviors. Epigenetic regulators are critical drivers of drug-induced changes in gene expression. Here, we demonstrate that the activity of an epigenetic enzyme promotes neuroplasticity within the nucleus accumbens (NAc) critical to cocaine action. In addition, we demonstrate that these changes in epigenetic activity drive cocaine-seeking behaviors in a cell-type-specific manner. These findings are key in understanding and targeting cocaine's impact of neural circuitry and behavior.
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19
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The Mechanisms of Peripheral Nerve Preconditioning Injury on Promoting Axonal Regeneration. Neural Plast 2021; 2021:6648004. [PMID: 33505458 PMCID: PMC7806370 DOI: 10.1155/2021/6648004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/21/2022] Open
Abstract
Two major factors contribute to the failure of axonal regrowth in the central nervous system (CNS), namely, the neuronal intrinsic regenerative capacity and the extrinsic local inhibitory microenvironments. However, a preconditioning peripheral nerve lesion could substantially enhance the regeneration of central axons following a subsequent spinal cord injury. In the present review, we summarize the molecular mechanisms of the preconditioning injury effect on promoting axonal regeneration. The injury signal transduction resulting from preconditioning peripheral nerve injury regulates the RAG expression to enhance axonal regeneration. Importantly, preconditioning peripheral nerve injury triggers interactions between neurons and nonneuronal cells to amplify and maintain their effects. Additionally, the preconditioning injury impacts mitochondria, protein, and lipid synthesis. All these coordinated changes endow axonal regeneration.
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20
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Park J, Lee DH. Functional roles of protein phosphatase 4 in multiple aspects of cellular physiology: a friend and a foe. BMB Rep 2021. [PMID: 32192570 PMCID: PMC7196183 DOI: 10.5483/bmbrep.2020.53.4.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein phosphatase 4 (PP4), one of serine/threonine phosphatases, is involved in many critical cellular pathways, including DNA damage response (DNA repair, cell cycle regulation, and apoptosis), tumorigenesis, cell migration, immune response, stem cell development, glucose metabolism, and diabetes. PP4 has been steadily studied over the past decade about wide spectrum of physiological activities in cells. Given the many vital functions in cells, PP4 has great potential to develop into the finding of key working mechanisms and effective treatments for related diseases such as cancer and diabetes. In this review, we provide an overview of the cellular and molecular mechanisms by which PP4 impacts and also discuss the functional significance of it in cell health.
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Affiliation(s)
- Jaehong Park
- School of Biological Sciences and Biotechnology Graduate School, Chonnam National University, Gwangju 61186, Korea
| | - Dong-Hyun Lee
- Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju 61186; Research Center of Ecomimetics, Chonnam National University, Gwangju 61186, Korea
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21
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Enriched conditioning expands the regenerative ability of sensory neurons after spinal cord injury via neuronal intrinsic redox signaling. Nat Commun 2020; 11:6425. [PMID: 33349630 PMCID: PMC7752916 DOI: 10.1038/s41467-020-20179-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022] Open
Abstract
Overcoming the restricted axonal regenerative ability that limits functional repair following a central nervous system injury remains a challenge. Here we report a regenerative paradigm that we call enriched conditioning, which combines environmental enrichment (EE) followed by a conditioning sciatic nerve axotomy that precedes a spinal cord injury (SCI). Enriched conditioning significantly increases the regenerative ability of dorsal root ganglia (DRG) sensory neurons compared to EE or a conditioning injury alone, propelling axon growth well beyond the spinal injury site. Mechanistically, we established that enriched conditioning relies on the unique neuronal intrinsic signaling axis PKC-STAT3-NADPH oxidase 2 (NOX2), enhancing redox signaling as shown by redox proteomics in DRG. Finally, NOX2 conditional deletion or overexpression respectively blocked or phenocopied enriched conditioning-dependent axon regeneration after SCI leading to improved functional recovery. These studies provide a paradigm that drives the regenerative ability of sensory neurons offering a potential redox-dependent regenerative model for mechanistic and therapeutic discoveries. Pre conditioning injury or environmental enrichment have been shown to promote axon regeneration. Here the authors show that environmental enrichment, combined with preconditioning injury promotes regeneration via a redox signalling dependent mechanism.
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22
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Rivard RS, Morris JM, Youngman MJ. The PP2A/4/6 subfamily of phosphoprotein phosphatases regulates DAF-16 and confers resistance to environmental stress in postreproductive adult C. elegans. PLoS One 2020; 15:e0229812. [PMID: 33315870 PMCID: PMC7735605 DOI: 10.1371/journal.pone.0229812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 11/13/2020] [Indexed: 11/28/2022] Open
Abstract
Insulin and insulin-like growth factors are longevity determinants that negatively regulate Forkhead box class O (FoxO) transcription factors. In C. elegans mutations that constitutively activate DAF-16, the ortholog of mammalian FoxO3a, extend lifespan by two-fold. While environmental insults induce DAF-16 activity in younger animals, it also becomes activated in an age-dependent manner in the absence of stress, modulating gene expression well into late adulthood. The mechanism by which DAF-16 activity is regulated during aging has not been defined. Since phosphorylation of DAF-16 generally leads to its inhibition, we asked whether phosphatases might be necessary for its increased transcriptional activity in adult C. elegans. We focused on the PP2A/4/6 subfamily of phosphoprotein phosphatases, members of which had been implicated to regulate DAF-16 under low insulin signaling conditions but had not been investigated during aging in wildtype animals. Using reverse genetics, we functionally characterized all C. elegans orthologs of human catalytic, regulatory, and scaffolding subunits of PP2A/4/6 holoenzymes in postreproductive adults. We found that PP2A complex constituents PAA-1 and PPTR-1 regulate DAF-16 transcriptional activity during aging and that they cooperate with the catalytic subunit LET-92 to protect adult animals from ultraviolet radiation. PP4 complex members PPH-4.1/4.2, and SMK-1 also appear to regulate DAF-16 in an age-dependent manner, and together with PPFR-2 they contribute to innate immunity. Interestingly, SUR-6 but no other subunit of the PP2A complex was necessary for the survival of pathogen-infected animals. Finally, we found that PP6 complex constituents PPH-6 and SAPS-1 contribute to host defense during aging, apparently without affecting DAF-16 transcriptional activity. Our studies indicate that a set of PP2A/4/6 complexes protect adult C. elegans from environmental stress, thus preserving healthspan. Therefore, along with their functions in cell division and development, the PP2A/4/6 phosphatases also appear to play critical roles later in life.
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Affiliation(s)
- Rebecca S. Rivard
- Department of Biology, Villanova University, Villanova, PA, United States of America
| | - Julia M. Morris
- Department of Biology, Villanova University, Villanova, PA, United States of America
| | - Matthew J. Youngman
- Department of Biology, Villanova University, Villanova, PA, United States of America
- * E-mail:
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23
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Nuclear receptor corepressors in intellectual disability and autism. Mol Psychiatry 2020; 25:2220-2236. [PMID: 32034290 PMCID: PMC7842082 DOI: 10.1038/s41380-020-0667-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 12/24/2019] [Accepted: 01/28/2020] [Indexed: 02/06/2023]
Abstract
Autism spectrum disorder (ASD) is characterized by neurocognitive dysfunctions, such as impaired social interaction and language learning. Gene-environment interactions have a pivotal role in ASD pathogenesis. Nuclear receptor corepressors (NCORs) are transcription co-regulators physically associated with histone deacetylases (HDACs) and many known players in ASD etiology such as transducin β-like 1 X-linked receptor 1 and methyl-CpG binding protein 2. The epigenome-modifying NCOR complex is sensitive to many ASD risk factors, including HDAC inhibitor valproic acid and a variety of endocrine factors, xenobiotic chemicals, or metabolites that can directly bind to multiple nuclear receptors. Here, we review recent studies of NCORs in neurocognition using animal models and human genetics approaches. We discuss functional interplays between NCORs and other known players in ASD etiology. It is conceivable that the NCOR complex may bridge the in utero environmental risk factors of ASD with epigenetic remodeling and can serve as a converging point for many gene-environment interactions in the pathogenesis of ASD and intellectual disability.
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Kong G, Zhou L, Serger E, Palmisano I, De Virgiliis F, Hutson TH, Mclachlan E, Freiwald A, La Montanara P, Shkura K, Puttagunta R, Di Giovanni S. AMPK controls the axonal regenerative ability of dorsal root ganglia sensory neurons after spinal cord injury. Nat Metab 2020; 2:918-933. [PMID: 32778834 DOI: 10.1038/s42255-020-0252-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/26/2020] [Indexed: 12/25/2022]
Abstract
Regeneration after injury occurs in axons that lie in the peripheral nervous system but fails in the central nervous system, thereby limiting functional recovery. Differences in axonal signalling in response to injury that might underpin this differential regenerative ability are poorly characterized. Combining axoplasmic proteomics from peripheral sciatic or central projecting dorsal root ganglion (DRG) axons with cell body RNA-seq, we uncover injury-dependent signalling pathways that are uniquely represented in peripheral versus central projecting sciatic DRG axons. We identify AMPK as a crucial regulator of axonal regenerative signalling that is specifically downregulated in injured peripheral, but not central, axons. We find that AMPK in DRG interacts with the 26S proteasome and its CaMKIIα-dependent regulatory subunit PSMC5 to promote AMPKα proteasomal degradation following sciatic axotomy. Conditional deletion of AMPKα1 promotes multiple regenerative signalling pathways after central axonal injury and stimulates robust axonal growth across the spinal cord injury site, suggesting inhibition of AMPK as a therapeutic strategy to enhance regeneration following spinal cord injury.
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Affiliation(s)
- Guiping Kong
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Luming Zhou
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Elisabeth Serger
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Ilaria Palmisano
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Francesco De Virgiliis
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Thomas H Hutson
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Eilidh Mclachlan
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Anja Freiwald
- Proteomics Core Facility, Institute of Molecular Biology, Mainz, Germany
| | - Paolo La Montanara
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Kirill Shkura
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK
| | - Radhika Puttagunta
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- University of Heidelberg, Heidelberg, Germany
| | - Simone Di Giovanni
- Division of Neuroscience, Department of Brain Sciences, Imperial College London, London, UK.
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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25
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Jara JS, Agger S, Hollis ER. Functional Electrical Stimulation and the Modulation of the Axon Regeneration Program. Front Cell Dev Biol 2020; 8:736. [PMID: 33015031 PMCID: PMC7462022 DOI: 10.3389/fcell.2020.00736] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/15/2020] [Indexed: 01/07/2023] Open
Abstract
Neural injury in mammals often leads to persistent functional deficits as spontaneous repair in the peripheral nervous system (PNS) is often incomplete, while endogenous repair mechanisms in the central nervous system (CNS) are negligible. Peripheral axotomy elicits growth-associated gene programs in sensory and motor neurons that can support reinnervation of peripheral targets given sufficient levels of debris clearance and proximity to nerve targets. In contrast, while damaged CNS circuitry can undergo a limited amount of sprouting and reorganization, this innate plasticity does not re-establish the original connectivity. The utility of novel CNS circuitry will depend on effective connectivity and appropriate training to strengthen these circuits. One method of enhancing novel circuit connectivity is through the use of electrical stimulation, which supports axon growth in both central and peripheral neurons. This review will focus on the effects of CNS and PNS electrical stimulation in activating axon growth-associated gene programs and supporting the recovery of motor and sensory circuits. Electrical stimulation-mediated neuroplasticity represents a therapeutically viable approach to support neural repair and recovery. Development of appropriate clinical strategies employing electrical stimulation will depend upon determining the underlying mechanisms of activity-dependent axon regeneration and the heterogeneity of neuronal subtype responses to stimulation.
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Affiliation(s)
| | - Sydney Agger
- Burke Neurological Institute, White Plains, NY, United States
| | - Edmund R Hollis
- Burke Neurological Institute, White Plains, NY, United States.,Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, United States
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26
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Nieuwenhuis B, Barber AC, Evans RS, Pearson CS, Fuchs J, MacQueen AR, van Erp S, Haenzi B, Hulshof LA, Osborne A, Conceicao R, Khatib TZ, Deshpande SS, Cave J, Ffrench‐Constant C, Smith PD, Okkenhaug K, Eickholt BJ, Martin KR, Fawcett JW, Eva R. PI 3-kinase delta enhances axonal PIP 3 to support axon regeneration in the adult CNS. EMBO Mol Med 2020; 12:e11674. [PMID: 32558386 PMCID: PMC7411663 DOI: 10.15252/emmm.201911674] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 12/27/2022] Open
Abstract
Peripheral nervous system (PNS) neurons support axon regeneration into adulthood, whereas central nervous system (CNS) neurons lose regenerative ability after development. To better understand this decline whilst aiming to improve regeneration, we focused on phosphoinositide 3-kinase (PI3K) and its product phosphatidylinositol (3,4,5)-trisphosphate (PIP3 ). We demonstrate that adult PNS neurons utilise two catalytic subunits of PI3K for axon regeneration: p110α and p110δ. However, in the CNS, axonal PIP3 decreases with development at the time when axon transport declines and regenerative competence is lost. Overexpressing p110α in CNS neurons had no effect; however, expression of p110δ restored axonal PIP3 and increased regenerative axon transport. p110δ expression enhanced CNS regeneration in both rat and human neurons and in transgenic mice, functioning in the same way as the hyperactivating H1047R mutation of p110α. Furthermore, viral delivery of p110δ promoted robust regeneration after optic nerve injury. These findings establish a deficit of axonal PIP3 as a key reason for intrinsic regeneration failure and demonstrate that native p110δ facilitates axon regeneration by functioning in a hyperactive fashion.
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Affiliation(s)
- Bart Nieuwenhuis
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
- Laboratory for Regeneration of Sensorimotor SystemsNetherlands Institute for NeuroscienceRoyal Netherlands Academy of Arts and Sciences (KNAW)AmsterdamThe Netherlands
| | - Amanda C Barber
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Rachel S Evans
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Craig S Pearson
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Joachim Fuchs
- Institute of BiochemistryCharité – Universitätsmedizin BerlinBerlinGermany
| | - Amy R MacQueen
- Laboratory of Lymphocyte Signalling and DevelopmentBabraham InstituteCambridgeUK
| | - Susan van Erp
- MRC Centre for Regenerative MedicineUniversity of EdinburghEdinburghUK
| | - Barbara Haenzi
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Lianne A Hulshof
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Andrew Osborne
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Raquel Conceicao
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Tasneem Z Khatib
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Sarita S Deshpande
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Joshua Cave
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | | | | | | | - Britta J Eickholt
- Institute of BiochemistryCharité – Universitätsmedizin BerlinBerlinGermany
| | - Keith R Martin
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
- Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneVic.Australia
- OphthalmologyDepartment of SurgeryUniversity of MelbourneMelbourneVic.Australia
| | - James W Fawcett
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
- Centre of Reconstructive NeuroscienceInstitute of Experimental MedicineCzech Academy of SciencesPragueCzech Republic
| | - Richard Eva
- John Van Geest Centre for Brain RepairDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
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27
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Rigoni M, Negro S. Signals Orchestrating Peripheral Nerve Repair. Cells 2020; 9:E1768. [PMID: 32722089 PMCID: PMC7464993 DOI: 10.3390/cells9081768] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/19/2020] [Accepted: 07/20/2020] [Indexed: 12/22/2022] Open
Abstract
The peripheral nervous system has retained through evolution the capacity to repair and regenerate after assault from a variety of physical, chemical, or biological pathogens. Regeneration relies on the intrinsic abilities of peripheral neurons and on a permissive environment, and it is driven by an intense interplay among neurons, the glia, muscles, the basal lamina, and the immune system. Indeed, extrinsic signals from the milieu of the injury site superimpose on genetic and epigenetic mechanisms to modulate cell intrinsic programs. Here, we will review the main intrinsic and extrinsic mechanisms allowing severed peripheral axons to re-grow, and discuss some alarm mediators and pro-regenerative molecules and pathways involved in the process, highlighting the role of Schwann cells as central hubs coordinating multiple signals. A particular focus will be provided on regeneration at the neuromuscular junction, an ideal model system whose manipulation can contribute to the identification of crucial mediators of nerve re-growth. A brief overview on regeneration at sensory terminals is also included.
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Affiliation(s)
- Michela Rigoni
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy;
- Myology Center (Cir-Myo), University of Padua, 35129 Padua, Italy
| | - Samuele Negro
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy;
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28
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Abstract
IMPACT STATEMENT Brain development and degeneration are highly complex processes that are regulated by a large number of molecules and signaling pathways the identities of which are being unraveled. Accumulating evidence points to histone deacetylases and epigenetic mechanisms as being important regulators of these processes. In this review, we describe that histone deacetylase-3 (HDAC3) is a particularly crucial regulator of both neurodevelopment and neurodegeneration. In addition, HDAC3 regulates memory formation, synaptic plasticity, and the cognitive impairment associated with normal aging. Understanding how HDAC3 functions contributes to the normal development and functioning of the brain while also promoting neurodegeneration could lead to the development of therapeutic approaches for neurodevelopmental, neuropsychiatric, and neurodegenerative disorders.
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29
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Smith TP, Sahoo PK, Kar AN, Twiss JL. Intra-axonal mechanisms driving axon regeneration. Brain Res 2020; 1740:146864. [PMID: 32360100 DOI: 10.1016/j.brainres.2020.146864] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/27/2022]
Abstract
Traumatic injury to the peripheral and central nervous systems very often causes axotomy, where an axon loses connections with its target resulting in loss of function. The axon segments distal to the injury site lose connection with the cell body and degenerate. Axotomized neurons in the periphery can spontaneously mount a regenerative response and reconnect to their denervated target tissues, though this is rarely complete in humans. In contrast, spontaneous regeneration rarely occurs after axotomy in the spinal cord and brain. Here, we concentrate on the mechanisms underlying this spontaneous regeneration in the peripheral nervous system, focusing on events initiated from the axon that support regenerative growth. We contrast this with what is known for axonal injury responses in the central nervous system. Considering the neuropathy focus of this special issue, we further draw parallels and distinctions between the injury-response mechanisms that initiate regenerative gene expression programs and those that are known to trigger axon degeneration.
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Affiliation(s)
- Terika P Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
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30
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Epigenomic signatures underpin the axonal regenerative ability of dorsal root ganglia sensory neurons. Nat Neurosci 2019; 22:1913-1924. [PMID: 31591560 DOI: 10.1038/s41593-019-0490-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 08/07/2019] [Indexed: 12/16/2022]
Abstract
Axonal injury results in regenerative success or failure, depending on whether the axon lies in the peripheral or the CNS, respectively. The present study addresses whether epigenetic signatures in dorsal root ganglia discriminate between regenerative and non-regenerative axonal injury. Chromatin immunoprecipitation for the histone 3 (H3) post-translational modifications H3K9ac, H3K27ac and H3K27me3; an assay for transposase-accessible chromatin; and RNA sequencing were performed in dorsal root ganglia after sciatic nerve or dorsal column axotomy. Distinct histone acetylation and chromatin accessibility signatures correlated with gene expression after peripheral, but not central, axonal injury. DNA-footprinting analyses revealed new transcriptional regulators associated with regenerative ability. Machine-learning algorithms inferred the direction of most of the gene expression changes. Neuronal conditional deletion of the chromatin remodeler CCCTC-binding factor impaired nerve regeneration, implicating chromatin organization in the regenerative competence. Altogether, the present study offers the first epigenomic map providing insight into the transcriptional response to injury and the differential regenerative ability of sensory neurons.
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