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Au NPB, Wu T, Chen X, Gao F, Li YTY, Tam WY, Yu KN, Geschwind DH, Coppola G, Wang X, Ma CHE. Genome-wide study reveals novel roles for formin-2 in axon regeneration as a microtubule dynamics regulator and therapeutic target for nerve repair. Neuron 2023; 111:3970-3987.e8. [PMID: 38086376 DOI: 10.1016/j.neuron.2023.11.011] [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: 10/26/2022] [Revised: 09/02/2023] [Accepted: 11/10/2023] [Indexed: 12/23/2023]
Abstract
Peripheral nerves regenerate successfully; however, clinical outcome after injury is poor. We demonstrated that low-dose ionizing radiation (LDIR) promoted axon regeneration and function recovery after peripheral nerve injury (PNI). Genome-wide CpG methylation profiling identified LDIR-induced hypermethylation of the Fmn2 promoter, exhibiting injury-induced Fmn2 downregulation in dorsal root ganglia (DRGs). Constitutive knockout or neuronal Fmn2 knockdown accelerated nerve repair and function recovery. Mechanistically, increased microtubule dynamics at growth cones was observed in time-lapse imaging of Fmn2-deficient DRG neurons. Increased HDAC5 phosphorylation and rapid tubulin deacetylation were found in regenerating axons of neuronal Fmn2-knockdown mice after injury. Growth-promoting effect of neuronal Fmn2 knockdown was eliminated by pharmaceutical blockade of HDAC5 or neuronal Hdac5 knockdown, suggesting that Fmn2deletion promotes axon regeneration via microtubule post-translational modification. In silico screening of FDA-approved drugs identified metaxalone, administered either immediately or 24-h post-injury, accelerating function recovery. This work uncovers a novel axon regeneration function of Fmn2 and a small-molecule strategy for PNI.
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Affiliation(s)
| | - Tan Wu
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China; Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Xinyu Chen
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Feng Gao
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China; Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | | | - Wing Yip Tam
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Kwan Ngok Yu
- Department of Physics, City University of Hong Kong, Hong Kong, China
| | - Daniel H Geschwind
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Giovanni Coppola
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xin Wang
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China; Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Chi Him Eddie Ma
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China.
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Moreira J, Martins H, Saraiva M, Saraiva MJ. TLR2 and 4 signaling pathways are altered in macrophages from V30M TTR mice with down-regulated expression of chemokines. Clin Sci (Lond) 2023; 137:355-366. [PMID: 36852978 DOI: 10.1042/cs20220656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 02/15/2023] [Accepted: 02/28/2023] [Indexed: 03/01/2023]
Abstract
Hereditary amyloid transthyretin (ATTRv) amyloidosis is a fatal neurodegenerative disorder, first identified in Portugal. The most common transthyretin (TTR) mutation in ATTRv results from an exchange of a methionine for a valine at position 30 (V30M). ATTRv is characterized by the extracellular deposition of aggregates and fibrils of mutant forms of TTR, particularly in the nerves and ganglia of the peripheral nervous system (PNS). This phenotype is often accompanied by the lack of inflammatory infiltrates, despite the importance of macrophages in removal of TTR deposits in ATTRv patients. The mechanisms underlying this impairment of inflammatory responses in ATTRv patients are poorly understood. Here, we show a significant down-regulation in the expression of several chemokines by bone marrow-derived macrophages (BMDM) generated from V30M TTR mice upon stimulation with toll-like receptor 4 (TLR4) and TLR2 agonists. The phosphorylation of the MAP kinase p38, important for TLR4 and TLR2 signaling pathways, was also down-regulated in V30M macrophages, as compared with wild-type (WT) ones. The present study contributes with new insights to unravel the molecular mechanisms underlying the lack of inflammatory immune responses observed in ATTRv patients and may help in the development of new immune therapeutic strategies for the disease.
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Affiliation(s)
- João Moreira
- Molecular Neurobiology Group, i3S - Instituto de Investigação e Inovação em Saúde, Department of Neurobiology and Neurologic Disorders, IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
- ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Department of Molecular Biology, Universidade do Porto, 4050-313 Porto, Portugal
| | - Helena Martins
- Molecular Neurobiology Group, i3S - Instituto de Investigação e Inovação em Saúde, Department of Neurobiology and Neurologic Disorders, IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Margarida Saraiva
- Immune Regulation Group, i3S - Instituto de Investigação e Inovação em Saúde, Department of Infection, Immunity,and Regeneration, IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Maria João Saraiva
- Molecular Neurobiology Group, i3S - Instituto de Investigação e Inovação em Saúde, Department of Neurobiology and Neurologic Disorders, IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
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Murakami T, Ito Y, Sango K, Watabe K, Sunada Y. Human transthyretin gene expression is markedly increased in repair Schwann cells in an in vitro model of hereditary transthyretin amyloidosis. Neurochem Int 2023; 164:105507. [PMID: 36796540 DOI: 10.1016/j.neuint.2023.105507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/09/2023] [Accepted: 02/12/2023] [Indexed: 02/16/2023]
Abstract
Hereditary transthyretin (TTR) amyloidosis (ATTRv) is characterized by TTR amyloid deposition in the peripheral nervous system. It remains unknown why variant TTR preferentially deposits in the peripheral nerves and dorsal root ganglia. We previously detected low levels of TTR expression in Schwann cells and established an immortalized Schwann cell line, TgS1, derived from a mouse model of ATTRv amyloidosis expressing the variant TTR gene. In the present study, the expression of TTR and Schwann cell marker genes was investigated in TgS1 cells by quantitative RT-PCR. TTR gene expression was markedly upregulated in TgS1 cells incubated in non-growth medium-Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum. The expression levels of c-Jun, Gdnf and Sox2 were increased, while Mpz was downregulated, suggesting that TgS1 cells exhibit a repair Schwann cell-like phenotype in the non-growth medium. Western blot analysis revealed that TTR protein was produced and secreted by the TgS1 cells. Furthermore, downregulation of Hsf1 with siRNA induced TTR aggregates in the TgS1 cells. These findings indicate that TTR expression is markedly increased in repair Schwann cells, likely to promote axonal regeneration. Therefore, aged dysfunctional repair Schwann cells may cause the deposition of variant TTR aggregates in the nerves of patients with ATTRv.
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Affiliation(s)
- Tatsufumi Murakami
- Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan; Faculty of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Okayama, 701-0193, Japan.
| | - Yuri Ito
- Faculty of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Okayama, 701-0193, Japan
| | - Kazunori Sango
- Diabetic Neuropathy Project, Department of Diseases and Infection, Tokyo Metropolitan Institute of Medical Science, Tokyo, 156-8506, Japan
| | - Kazuhiko Watabe
- Department of Medical Technology, Faculty of Health Sciences, Kyorin University, Tokyo, 181-8612, Japan
| | - Yoshihide Sunada
- Department of Neurology, Kawasaki Medical School, Kurashiki, Okayama, 701-0192, Japan
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Pero ME, Chowdhury F, Bartolini F. Role of tubulin post-translational modifications in peripheral neuropathy. Exp Neurol 2023; 360:114274. [PMID: 36379274 DOI: 10.1016/j.expneurol.2022.114274] [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: 09/09/2022] [Revised: 11/06/2022] [Accepted: 11/08/2022] [Indexed: 11/14/2022]
Abstract
Peripheral neuropathy is a common disorder that results from nerve damage in the periphery. The degeneration of sensory axon terminals leads to changes or loss of sensory functions, often manifesting as debilitating pain, weakness, numbness, tingling, and disability. The pathogenesis of most peripheral neuropathies remains to be fully elucidated. Cumulative evidence from both early and recent studies indicates that tubulin damage may provide a common underlying mechanism of axonal injury in various peripheral neuropathies. In particular, tubulin post-translational modifications have been recently implicated in both toxic and inherited forms of peripheral neuropathy through regulation of axonal transport and mitochondria dynamics. This knowledge forms a new area of investigation with the potential for developing therapeutic strategies to prevent or delay peripheral neuropathy by restoring tubulin homeostasis.
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Affiliation(s)
- Maria Elena Pero
- Department of Pathology and Cell Biology, Columbia University, New York, USA; Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Italy
| | - Farihah Chowdhury
- Department of Pathology and Cell Biology, Columbia University, New York, USA
| | - Francesca Bartolini
- Department of Pathology and Cell Biology, Columbia University, New York, USA.
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Yang C, Zhao X, An X, Zhang Y, Sun W, Zhang Y, Duan Y, Kang X, Sun Y, Jiang L, Lian F. Axonal transport deficits in the pathogenesis of diabetic peripheral neuropathy. Front Endocrinol (Lausanne) 2023; 14:1136796. [PMID: 37056668 PMCID: PMC10086245 DOI: 10.3389/fendo.2023.1136796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a chronic and prevalent metabolic disease that gravely endangers human health and seriously affects the quality of life of hyperglycemic patients. More seriously, it can lead to amputation and neuropathic pain, imposing a severe financial burden on patients and the healthcare system. Even with strict glycemic control or pancreas transplantation, peripheral nerve damage is difficult to reverse. Most current treatment options for DPN can only treat the symptoms but not the underlying mechanism. Patients with long-term diabetes mellitus (DM) develop axonal transport dysfunction, which could be an important factor in causing or exacerbating DPN. This review explores the underlying mechanisms that may be related to axonal transport impairment and cytoskeletal changes caused by DM, and the relevance of the latter with the occurrence and progression of DPN, including nerve fiber loss, diminished nerve conduction velocity, and impaired nerve regeneration, and also predicts possible therapeutic strategies. Understanding the mechanisms of diabetic neuronal injury is essential to prevent the deterioration of DPN and to develop new therapeutic strategies. Timely and effective improvement of axonal transport impairment is particularly critical for the treatment of peripheral neuropathies.
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Satapathy S, Wilson M. Roles of constitutively secreted extracellular chaperones in neuronal cell repair and regeneration. Neural Regen Res 2023; 18:769-772. [PMID: 36204835 PMCID: PMC9700095 DOI: 10.4103/1673-5374.353483] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Protein quality control involves many processes that jointly act to regulate the expression, localization, turnover, and degradation of proteins, and has been highlighted in recent studies as critical to the differentiation of stem cells during regeneration. The roles of constitutively secreted extracellular chaperones in neuronal injury and disease are poorly understood. Extracellular chaperones are multifunctional proteins expressed by many cell types, including those of the nervous system, known to facilitate protein quality control processes. These molecules exert pleiotropic effects and have been implicated as playing important protective roles in a variety of stress conditions, including tissue damage, infections, and local tissue inflammation. This article aims to provide a critical review of what is currently known about the functions of extracellular chaperones in neuronal repair and regeneration and highlight future directions for this important research area. We review what is known of four constitutively secreted extracellular chaperones directly implicated in processes of neuronal damage and repair, including transthyretin, clusterin, α2-macroglobulin, and neuroserpin, and propose that investigation into the effects of these and other extracellular chaperones on neuronal repair and regeneration has the potential to yield valuable new therapies.
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