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Langley A, Abeling-Wang S, Wagner E, Salogiannis J. Movement of the endoplasmic reticulum is driven by multiple classes of vesicles marked by Rab-GTPases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.14.592021. [PMID: 38798686 PMCID: PMC11118391 DOI: 10.1101/2024.05.14.592021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Peripheral endoplasmic reticulum (ER) tubules move along microtubules to interact with various organelles through membrane contact sites (MCS). Traditionally, ER moves by either sliding along stable microtubules via molecular motors or attaching to the plus ends of dynamic microtubules through tip attachment complexes (TAC). A recently discovered third process, hitchhiking, involves motile vesicles pulling ER tubules along microtubules. Previous research showed that ER hitchhikes on Rab5- and Rab7-marked endosomes, but it is uncertain if other Rab-vesicles can do the same. In U2OS cells, we screened Rabs for their ability to cotransport with ER tubules and found that ER hitchhikes on post-Golgi vesicles marked by Rab6 (isoforms a and b). Rab6-ER hitchhiking occurs independently of ER-endolysosome contacts and TAC-mediated ER movement. Disrupting either Rab6 or the motility of Rab6-vesicles reduces overall ER movement. Conversely, relocating these vesicles to the cell periphery causes peripheral ER accumulation, indicating that Rab6-vesicle motility is crucial for a subset of ER movements. Proximal post-Golgi vesicles marked by TGN46 are involved in Rab6-ER hitchhiking, while other post-Golgi vesicles (Rabs 8/10/11/13/14) are not essential for ER movement. Our further analysis finds that ER to Golgi vesicles marked by Rab1 are also capable of driving a subset of ER movements. Taken together, our findings suggest that ER hitchhiking on Rab-vesicles is a significant mode of ER movement. SIGNIFICANCE STATEMENT Peripheral endoplasmic reticulum tubules move on microtubules by either attaching to motors (cargo adaptor-mediated), dynamic microtubule-plus ends (tip attachment complexes) or motile vesicles (hitchhiking) but the prevalence of each mode is not clearPost-Golgi vesicles marked by Rab6/TGN46 and ER to Golgi vesicles marked by Rab1 drive ER movementsER hitchhiking on multiple classes of vesicles (endolysosomal, post-Golgi and ER to Golgi) marked by Rabs plays a prominent role in ER movement.
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Zhao WJ, Fan CL, Hu XM, Ban XX, Wan H, He Y, Zhang Q, Xiong K. Regulated Cell Death of Retinal Ganglion Cells in Glaucoma: Molecular Insights and Therapeutic Potentials. Cell Mol Neurobiol 2023; 43:3161-3178. [PMID: 37338781 DOI: 10.1007/s10571-023-01373-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 06/05/2023] [Indexed: 06/21/2023]
Abstract
Glaucoma is a group of diseases characterized by the degeneration of retinal ganglion cells (RGCs) and progressive, irreversible vision loss. High intraocular pressure (IOP) heightens the likelihood of glaucoma and correlates with RGC loss. While the current glaucoma therapy prioritizes lower the IOP; however, RGC, and visual loss may persist even when the IOP is well-controlled. As such, discovering and creating IOP-independent neuroprotective strategies for safeguard RGCs is crucial for glaucoma management. Investigating and clarifying the mechanism behind RGC death to counteract its effects is a promising direction for glaucoma control. Empirical studies of glaucoma reveal the role of multiple regulated cell death (RCD) pathways in RGC death. This review delineates the RCD of RGCs following IOP elevation and optic nerve damage and discusses the substantial benefits of mitigating RCD in RGCs in preserving visual function.
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Affiliation(s)
- Wen-Juan Zhao
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Hunan Province, No. 172, Tongzipo Road, Yuelu District, Changsha City, 410013, China
| | - Chun-Ling Fan
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Hunan Province, No. 172, Tongzipo Road, Yuelu District, Changsha City, 410013, China
| | - Xi-Min Hu
- Department of Dermatology, Xiangya Hospital, Central South University, Hunan Province, No. 172, Tongzipo Road, Yuelu District, Changsha City, 410013, China
| | - Xiao-Xia Ban
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Hunan Province, No. 172, Tongzipo Road, Yuelu District, Changsha City, 410013, China
| | - Hao Wan
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Hunan Province, No. 172, Tongzipo Road, Yuelu District, Changsha City, 410013, China
| | - Ye He
- Changsha Aier Eye Hospital, Hunan Province, No. 188, Furong Road, Furong District, Changsha City, 410015, China
| | - Qi Zhang
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Hunan Province, No. 172, Tongzipo Road, Yuelu District, Changsha City, 410013, China.
- Key Laboratory of Emergency and Trauma of Ministry of Education, Hainan Medical University, Haikou, 571199, China.
| | - Kun Xiong
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Hunan Province, No. 172, Tongzipo Road, Yuelu District, Changsha City, 410013, China.
- Key Laboratory of Emergency and Trauma of Ministry of Education, Hainan Medical University, Haikou, 571199, China.
- Hunan Key Laboratory of Ophthalmology, Changsha, 410013, China.
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Zhiguo F, Ji W, Shenyuan C, Guoyou Z, Chen K, Hui Q, Wenrong X, Zhai X. A swift expanding trend of extracellular vesicles in spinal cord injury research: a bibliometric analysis. J Nanobiotechnology 2023; 21:289. [PMID: 37612689 PMCID: PMC10463993 DOI: 10.1186/s12951-023-02051-6] [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: 06/19/2023] [Accepted: 08/04/2023] [Indexed: 08/25/2023] Open
Abstract
Extracellular vesicles (EVs) in the field of spinal cord injury (SCI) have garnered significant attention for their potential applications in diagnosis and therapy. However, no bibliometric assessment has been conducted to evaluate the scientific progress in this area. A search of articles in Web of Science (WoS) from January 1, 1991, to May 1, 2023, yielded 359 papers that were analyzed using various online analysis tools. These articles have been cited 10,842 times with 30.2 times per paper. The number of publications experienced explosive growth starting in 2015. China and the United States led this research initiative. Keywords were divided into 3 clusters, including "Pathophysiology of SCI", "Bioactive components of EVs", and "Therapeutic effects of EVs in SCI". By integrating the average appearing year (AAY) of keywords in VoSviewer with the time zone map of the Citation Explosion in CiteSpace, the focal point of research has undergone a transformative shift. The emphasis has moved away from pathophysiological factors such as "axon", "vesicle", and "glial cell" to more mechanistic and applied domains such as "activation", "pathways", "hydrogels" and "therapy". In conclusions, institutions are expected to allocate more resources towards EVs-loaded hydrogel therapy and the utilization of innovative materials for injury mitigation.
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Affiliation(s)
- Fan Zhiguo
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai, 200433, China
| | - Wu Ji
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai, 200433, China
| | - Chen Shenyuan
- Key Laboratory of Laboratory Medicine of Jiangsu Province, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Zhang Guoyou
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai, 200433, China
| | - Kai Chen
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai, 200433, China.
| | - Qian Hui
- Key Laboratory of Laboratory Medicine of Jiangsu Province, School of Medicine, Jiangsu University, Zhenjiang, China.
| | - Xu Wenrong
- Key Laboratory of Laboratory Medicine of Jiangsu Province, School of Medicine, Jiangsu University, Zhenjiang, China.
| | - Xiao Zhai
- Department of Orthopedics, Shanghai Changhai Hospital, Shanghai, 200433, China.
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Smith G, Sweeney ST, O’Kane CJ, Prokop A. How neurons maintain their axons long-term: an integrated view of axon biology and pathology. Front Neurosci 2023; 17:1236815. [PMID: 37564364 PMCID: PMC10410161 DOI: 10.3389/fnins.2023.1236815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
Axons are processes of neurons, up to a metre long, that form the essential biological cables wiring nervous systems. They must survive, often far away from their cell bodies and up to a century in humans. This requires self-sufficient cell biology including structural proteins, organelles, and membrane trafficking, metabolic, signalling, translational, chaperone, and degradation machinery-all maintaining the homeostasis of energy, lipids, proteins, and signalling networks including reactive oxygen species and calcium. Axon maintenance also involves specialised cytoskeleton including the cortical actin-spectrin corset, and bundles of microtubules that provide the highways for motor-driven transport of components and organelles for virtually all the above-mentioned processes. Here, we aim to provide a conceptual overview of key aspects of axon biology and physiology, and the homeostatic networks they form. This homeostasis can be derailed, causing axonopathies through processes of ageing, trauma, poisoning, inflammation or genetic mutations. To illustrate which malfunctions of organelles or cell biological processes can lead to axonopathies, we focus on axonopathy-linked subcellular defects caused by genetic mutations. Based on these descriptions and backed up by our comprehensive data mining of genes linked to neural disorders, we describe the 'dependency cycle of local axon homeostasis' as an integrative model to explain why very different causes can trigger very similar axonopathies, providing new ideas that can drive the quest for strategies able to battle these devastating diseases.
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Affiliation(s)
- Gaynor Smith
- Cardiff University, School of Medicine, College of Biomedical and Life Sciences, Cardiff, United Kingdom
| | - Sean T. Sweeney
- Department of Biology, University of York and York Biomedical Research Institute, York, United Kingdom
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, The University of Manchester, Manchester, United Kingdom
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Elfmark LA, Wenzel EM, Wang L, Pedersen NM, Stenmark H, Raiborg C. Protrudin-mediated ER-endosome contact sites promote phagocytosis. Cell Mol Life Sci 2023; 80:216. [PMID: 37468729 PMCID: PMC10356898 DOI: 10.1007/s00018-023-04862-0] [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: 03/23/2023] [Revised: 07/06/2023] [Accepted: 07/08/2023] [Indexed: 07/21/2023]
Abstract
During phagocytosis, endosomes both contribute with membrane to forming phagosomes and promote phagosome maturation. However, how these vesicles are delivered to the phagocytic cup and the phagosome has been unknown. Here, we show that Protrudin-mediated endoplasmic reticulum (ER)-endosome contact sites facilitate anterograde translocation of FYCO1 and VAMP7-positive late endosomes and lysosomes (LELys) to forming phagocytic cups in a retinal pigment epithelial-derived cell line (RPE1). Protrudin-dependent phagocytic cup formation required SYT7, which promotes fusion of LELys with the plasma membrane. RPE1 cells perform phagocytosis of dead cells (efferocytosis) that expose phosphatidylserine (PS) on their surface. Exogenous addition of apoptotic bodies increased the formation of phagocytic cups, which further increased when Protrudin was overexpressed. Overexpression of Protrudin also led to elevated uptake of silica beads coated with PS. Conversely, Protrudin depletion or abrogation of ER-endosome contact sites inhibited phagocytic cup formation resulting in reduced uptake of PS-coated beads. Thus, the Protrudin pathway delivers endosomes to facilitate formation of the phagocytic cup important for PS-dependent phagocytosis.
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Affiliation(s)
- Liv Anker Elfmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Eva Maria Wenzel
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Ling Wang
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Nina Marie Pedersen
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Camilla Raiborg
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway.
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
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6
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Cheah M, Cheng Y, Petrova V, Cimpean A, Jendelova P, Swarup V, Woolf CJ, Geschwind DH, Fawcett JW. Integrin-Driven Axon Regeneration in the Spinal Cord Activates a Distinctive CNS Regeneration Program. J Neurosci 2023; 43:4775-4794. [PMID: 37277179 PMCID: PMC10312060 DOI: 10.1523/jneurosci.2076-22.2023] [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: 11/06/2022] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 06/07/2023] Open
Abstract
The peripheral branch of sensory dorsal root ganglion (DRG) neurons regenerates readily after injury unlike their central branch in the spinal cord. However, extensive regeneration and reconnection of sensory axons in the spinal cord can be driven by the expression of α9 integrin and its activator kindlin-1 (α9k1), which enable axons to interact with tenascin-C. To elucidate the mechanisms and downstream pathways affected by activated integrin expression and central regeneration, we conducted transcriptomic analyses of adult male rat DRG sensory neurons transduced with α9k1, and controls, with and without axotomy of the central branch. Expression of α9k1 without the central axotomy led to upregulation of a known PNS regeneration program, including many genes associated with peripheral nerve regeneration. Coupling α9k1 treatment with dorsal root axotomy led to extensive central axonal regeneration. In addition to the program upregulated by α9k1 expression, regeneration in the spinal cord led to expression of a distinctive CNS regeneration program, including genes associated with ubiquitination, autophagy, endoplasmic reticulum (ER), trafficking, and signaling. Pharmacological inhibition of these processes blocked the regeneration of axons from DRGs and human iPSC-derived sensory neurons, validating their causal contributions to sensory regeneration. This CNS regeneration-associated program showed little correlation with either embryonic development or PNS regeneration programs. Potential transcriptional drivers of this CNS program coupled to regeneration include Mef2a, Runx3, E2f4, and Yy1. Signaling from integrins primes sensory neurons for regeneration, but their axon growth in the CNS is associated with an additional distinctive program that differs from that involved in PNS regeneration.SIGNIFICANCE STATEMENT Restoration of neurologic function after spinal cord injury has yet to be achieved in human patients. To accomplish this, severed nerve fibers must be made to regenerate. Reconstruction of nerve pathways has not been possible, but recently, a method for stimulating long-distance axon regeneration of sensory fibers in rodents has been developed. This research uses profiling of messenger RNAs in the regenerating sensory neurons to discover which mechanisms are activated. This study shows that the regenerating neurons initiate a novel CNS regeneration program which includes molecular transport, autophagy, ubiquitination, and modulation of the endoplasmic reticulum (ER). The study identifies mechanisms that neurons need to activate to regenerate their nerve fibers.
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Affiliation(s)
- Menghon Cheah
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, United Kingdom
| | - Yuyan Cheng
- Program in Neurogenetics, Department of Neurology, and Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095
| | - Veselina Petrova
- Department of Neurobiology, Harvard Medical School; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts 02115
| | - Anda Cimpean
- Centre for Reconstructive Neuroscience, Institute of Experimental Medicine Czech Academy of Science, Prague, Czech Republic
| | - Pavla Jendelova
- Centre for Reconstructive Neuroscience, Institute of Experimental Medicine Czech Academy of Science, Prague, Czech Republic
| | - Vivek Swarup
- Program in Neurogenetics, Department of Neurology, and Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095
- Department of Neurobiology and Behavior, University of California, Irvine, California 92697
| | - Clifford J Woolf
- Department of Neurobiology, Harvard Medical School; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts 02115
| | - Daniel H Geschwind
- Program in Neurogenetics, Department of Neurology, and Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095
| | - James W Fawcett
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, United Kingdom
- Centre for Reconstructive Neuroscience, Institute of Experimental Medicine Czech Academy of Science, Prague, Czech Republic
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Liu X, Zhao Y, Zou W. Molecular mechanisms of neurite regeneration and repair: insights from C. elegans and Drosophila. CELL REGENERATION (LONDON, ENGLAND) 2023; 12:12. [PMID: 37005942 PMCID: PMC10067779 DOI: 10.1186/s13619-022-00155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/01/2022] [Indexed: 04/04/2023]
Abstract
The difficulties of injured and degenerated neurons to regenerate neurites and regain functions are more significant than in other body tissues, making neurodegenerative and related diseases hard to cure. Uncovering the secrets of neural regeneration and how this process may be inhibited after injury will provide insights into novel management and potential treatments for these diseases. Caenorhabditis elegans and Drosophila melanogaster are two of the most widely used and well-established model organisms endowed with advantages in genetic manipulation and live imaging to explore this fundamental question about neural regeneration. Here, we review the classical models and techniques, and the involvement and cooperation of subcellular structures during neurite regeneration using these two organisms. Finally, we list several important open questions that we look forward to inspiring future research.
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Affiliation(s)
- Xiaofan Liu
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Yuqing Zhao
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
- Institute of Zhejiang University and University of Edinburgh, Jiaxing, China
| | - Wei Zou
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China.
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China.
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8
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Hakim A, Guido B, Narsineni L, Chen DW, Foldvari M. Gene therapy strategies for glaucoma from IOP reduction to retinal neuroprotection: progress towards non-viral systems. Adv Drug Deliv Rev 2023; 196:114781. [PMID: 36940751 DOI: 10.1016/j.addr.2023.114781] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/25/2023] [Accepted: 03/15/2023] [Indexed: 03/23/2023]
Abstract
Glaucoma is the result of the gradual death of retinal ganglion cells (RGCs) whose axons form the optic nerve. Elevated intraocular pressure (IOP) is a major risk factors thatcontributes to RGC apoptosis and axonal loss at the lamina cribrosa, resulting in progressive reduction and eventual anterograde-retrograde transport blockade of neurotrophic factors. Current glaucoma management mainly focuses on pharmacological or surgical lowering of IOP, to manage the only modifiable risk factor. Although IOP reduction delays disease progression, it does not address previous and ongoing optic nerve degeneration. Gene therapy is a promising direction to control or modify genes involved in the pathophysiology of glaucoma. Both viral and non-viral gene therapy delivery systems are emerging as promising alternatives or add-on therapies to traditional treatments for improving IOP control and provide neuroprotection. The specific spotlight on non-viral gene delivery systems shows further progress towards improving the safety of gene therapy and implementing neuroprotection by targeting specific tissues and cells in the eye and specifically in the retina.
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Affiliation(s)
- Antoine Hakim
- School of Pharmacy, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1
| | - Benjamin Guido
- School of Pharmacy, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1
| | - Lokesh Narsineni
- School of Pharmacy, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1
| | - Ding-Wen Chen
- School of Pharmacy, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1
| | - Marianna Foldvari
- School of Pharmacy, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1; Waterloo Institute of Nanotechnology and Center for Bioengineering and Biotechnology University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1.
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9
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Kim HN, McCrea MR, Li S. Advances in molecular therapies for targeting pathophysiology in spinal cord injury. Expert Opin Ther Targets 2023; 27:171-187. [PMID: 37017093 PMCID: PMC10148912 DOI: 10.1080/14728222.2023.2194532] [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: 01/23/2023] [Revised: 03/20/2023] [Accepted: 03/20/2023] [Indexed: 04/06/2023]
Abstract
INTRODUCTION Spinal cord injury (SCI) affects 25,000-50,000 people around the world each year and there is no cure for SCI patients currently. The primary injury damages spinal cord tissues and secondary injury mechanisms, including ischemia, apoptosis, inflammation, and astrogliosis, further exacerbate the lesions to the spinal cord. Recently, researchers have designed various therapeutic approaches for SCI by targeting its major cellular or molecular pathophysiology. AREAS COVERED Some strategies have shown promise in repairing injured spinal cord for functional recoveries, such as administering neuroprotective reagents, targeting specific genes to promote robust axon regeneration of disconnected spinal fiber tracts, targeting epigenetic factors to enhance cell survival and neural repair, and facilitating neuronal relay pathways and neuroplasticity for restoration of function after SCI. This review focuses on the major advances in preclinical molecular therapies for SCI reported in recent years. EXPERT OPINION Recent progress in developing novel and effective repairing strategies for SCI is encouraging, but many challenges remain for future design of effective treatments, including developing highly effective neuroprotectants for early interventions, stimulating robust neuronal regeneration with functional synaptic reconnections among disconnected neurons, maximizing the recovery of lost neural functions with combination strategies, and translating the most promising therapies into human use.
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Affiliation(s)
- Ha Neui Kim
- Shriners Hospitals Pediatric Research Center, Department of Neural Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Madeline R. McCrea
- Shriners Hospitals Pediatric Research Center, Department of Neural Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Department of Neural Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
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Rizk E, Madrid A, Koueik J, Sun D, Stewart K, Chen D, Luo S, Hong F, Papale LA, Hariharan N, Alisch RS, Iskandar BJ. Purified regenerating retinal neurons reveal regulatory role of DNA methylation-mediated Na+/K+-ATPase in murine axon regeneration. Commun Biol 2023; 6:120. [PMID: 36717618 PMCID: PMC9886953 DOI: 10.1038/s42003-023-04463-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/11/2023] [Indexed: 01/31/2023] Open
Abstract
While embryonic mammalian central nervous system (CNS) axons readily grow and differentiate, only a minority of fully differentiated mature CNS neurons are able to regenerate injured axons, leading to stunted functional recovery after injury and disease. To delineate DNA methylation changes specifically associated with axon regeneration, we used a Fluorescent-Activated Cell Sorting (FACS)-based methodology in a rat optic nerve transection model to segregate the injured retinal ganglion cells (RGCs) into regenerating and non-regenerating cell populations. Whole-genome DNA methylation profiling of these purified neurons revealed genes and pathways linked to mammalian RGC regeneration. Moreover, whole-methylome sequencing of purified uninjured adult and embryonic RGCs identified embryonic molecular profiles reactivated after injury in mature neurons, and others that correlate specifically with embryonic or adult axon growth, but not both. The results highlight the contribution to both embryonic growth and adult axon regeneration of subunits encoding the Na+/K+-ATPase. In turn, both biochemical and genetic inhibition of the Na+/K+-ATPase pump significantly reduced RGC axon regeneration. These data provide critical molecular insights into mammalian CNS axon regeneration, pinpoint the Na+/K+-ATPase as a key regulator of regeneration of injured mature CNS axons, and suggest that successful regeneration requires, in part, reactivation of embryonic signals.
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Affiliation(s)
- Elias Rizk
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA ,grid.240473.60000 0004 0543 9901Department of Neurological Surgery, Penn State Milton S. Hershey Medical Center, Hershey, PA 17033 USA
| | - Andy Madrid
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Joyce Koueik
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Dandan Sun
- grid.21925.3d0000 0004 1936 9000Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213 USA
| | - Krista Stewart
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - David Chen
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Susan Luo
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Felissa Hong
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Ligia A. Papale
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Nithya Hariharan
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Reid S. Alisch
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
| | - Bermans J. Iskandar
- grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53792 USA
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11
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Molecular machinery regulating organelle dynamics during axon growth and guidance. Semin Cell Dev Biol 2023; 133:3-9. [PMID: 35227625 DOI: 10.1016/j.semcdb.2022.02.019] [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: 10/26/2021] [Revised: 01/24/2022] [Accepted: 02/21/2022] [Indexed: 11/23/2022]
Abstract
Axon growth and guidance in the developing nervous system rely on intracellular membrane dynamics that involve endosome maturation and transport, as well as its regulated tethering to the endoplasmic reticulum (ER). Recent studies have identified several key molecules, such as protrudin, which plays a dynamic role at membrane contact sites between the ER and endosomes/lysosomes, and myosin Va, which acts as a sensor for ER-derived Ca2+ that triggers peri-ER membrane export. These molecules form different types of multiprotein complexes at the interface of organelles and, in response to their surrounding microenvironments, such as Ca2+ concentrations and lipid contents, regulate the directional movement of endosomal vesicles in extending axons. Here, we review the molecular mechanisms underlying membrane dynamics and inter-organelle interactions during neuronal morphogenesis.
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12
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Nieuwenhuis B, Laperrousaz E, Tribble JR, Verhaagen J, Fawcett JW, Martin KR, Williams PA, Osborne A. Improving adeno-associated viral (AAV) vector-mediated transgene expression in retinal ganglion cells: comparison of five promoters. Gene Ther 2023:10.1038/s41434-022-00380-z. [PMID: 36635457 DOI: 10.1038/s41434-022-00380-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 12/02/2022] [Accepted: 12/21/2022] [Indexed: 01/14/2023]
Abstract
Recombinant adeno-associated viral vectors (AAVs) are an effective system for gene transfer. AAV serotype 2 (AAV2) is commonly used to deliver transgenes to retinal ganglion cells (RGCs) via intravitreal injection. The AAV serotype however is not the only factor contributing to the effectiveness of gene therapies. Promoters influence the strength and cell-selectivity of transgene expression. This study compares five promoters designed to maximise AAV2 cargo space for gene delivery: chicken β-actin (CBA), cytomegalovirus (CMV), short CMV early enhancer/chicken β-actin/short β-globulin intron (sCAG), mouse phosphoglycerate kinase (PGK), and human synapsin (SYN). The promoters driving enhanced green fluorescent protein (eGFP) were examined in adult C57BL/6J mice eyes and tissues of the visual system. eGFP expression was strongest in the retina, optic nerves and brain when driven by the sCAG and SYN promoters. CBA, CMV, and PGK had moderate expression by comparison. The SYN promoter had almost exclusive transgene expression in RGCs. The PGK promoter had predominant expression in both RGCs and AII amacrine cells. The ubiquitous CBA, CMV, and sCAG promoters expressed eGFP in a variety of cell types across multiple retinal layers including Müller glia and astrocytes. We also found that these promoters could transduce human retina ex vivo, although expression was predominantly in glial cells due to low RGC viability. Taken together, this promoter comparison study contributes to optimising AAV-mediated transduction in the retina, and could be valuable for research in ocular disorders, particularly those with large or complex genetic cargos.
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Affiliation(s)
- Bart Nieuwenhuis
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK. .,Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| | - Elise Laperrousaz
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Joost Verhaagen
- Laboratory for Regeneration of Sensorimotor Systems, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands.,Centre for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - James W Fawcett
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Centre of Reconstructive Neuroscience, Institute of Experimental Medicine, Prague, Czech Republic
| | - Keith R Martin
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Andrew Osborne
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK. .,Ikarovec Ltd, The Norwich Research Park Innovation Centre, Norwich, UK.
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13
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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: 48] [Impact Index Per Article: 48.0] [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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14
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Ahmed Z. Optic Nerve Crush Injury in Rodents to Study Retinal Ganglion Cell Neuroprotection and Regeneration. Methods Mol Biol 2023; 2708:99-106. [PMID: 37558963 DOI: 10.1007/978-1-0716-3409-7_10] [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] [Indexed: 08/11/2023]
Abstract
Optic nerve crush injury is a useful model for studying the response of central nervous system neurons (CNS) to injury. A particular focus of this model has been to elucidate therapeutic factors in promoting neuroprotection and axon regeneration after injury. Here we describe a step-by-step protocol in accessing the optic nerve and creating a crush injury. This can be used to create a reproducible model to study the response of retinal ganglion cells (RGC), the main projection neurons of the eye, to injury.
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Affiliation(s)
- Zubair Ahmed
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.
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15
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Subra M, Grimanelli Z, Gautier R, Mesmin B. Stranger Twins: A Tale of Resemblance and Contrast Between VAP Proteins. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231183897. [PMID: 37455812 PMCID: PMC10345920 DOI: 10.1177/25152564231183897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 06/06/2023] [Indexed: 07/18/2023]
Abstract
When considering the vesicle-associated membrane protein-associated protein (VAP) family, major receptors at the surface of the endoplasmic reticulum (ER), it appears that VAP-A and VAP-B paralogs largely overlap in structure and function, and that specific features to distinguish these two proteins hardly exist or are poorly documented. Here, we question the degree of redundancy between VAP-A and VAP-B: is one simply a backup plan, in case of loss of function of one of the two genes, or are there molecular and functional divergences that would explain their maintenance during evolution?
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Affiliation(s)
- Mélody Subra
- Institut de Pharmacologie Moléculaire et Cellulaire, Inserm, CNRS, Université Côte d’Azur, Valbonne, France
| | - Zoé Grimanelli
- Institut de Pharmacologie Moléculaire et Cellulaire, Inserm, CNRS, Université Côte d’Azur, Valbonne, France
| | - Romain Gautier
- Institut de Pharmacologie Moléculaire et Cellulaire, Inserm, CNRS, Université Côte d’Azur, Valbonne, France
| | - Bruno Mesmin
- Institut de Pharmacologie Moléculaire et Cellulaire, Inserm, CNRS, Université Côte d’Azur, Valbonne, France
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16
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Swope RD, Hertzler JI, Stone MC, Kothe GO, Rolls MM. The exocyst complex is required for developmental and regenerative neurite growth in vivo. Dev Biol 2022; 492:1-13. [PMID: 36162553 PMCID: PMC10228574 DOI: 10.1016/j.ydbio.2022.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/13/2022] [Accepted: 09/19/2022] [Indexed: 11/30/2022]
Abstract
The exocyst complex is an important regulator of intracellular trafficking and tethers secretory vesicles to the plasma membrane. Understanding of its role in neuron outgrowth remains incomplete, and previous studies have come to different conclusions about its importance for axon and dendrite growth, particularly in vivo. To investigate exocyst function in vivo we used Drosophila sensory neurons as a model system. To bypass early developmental requirements in other cell types, we used neuron-specific RNAi to target seven exocyst subunits. Initial neuronal development proceeded normally in these backgrounds, however, we considered this could be due to residual exocyst function. To probe neuronal growth capacity at later times after RNAi initiation, we used laser microsurgery to remove axons or dendrites and prompt regrowth. Exocyst subunit RNAi reduced axon regeneration, although new axons could be specified. In control neurons, a vesicle trafficking marker often concentrated in the new axon, but this pattern was disrupted in Sec6 RNAi neurons. Dendrite regeneration was also severely reduced by exocyst RNAi, even though the trafficking marker did not accumulate in a strongly polarized manner during normal dendrite regeneration. The requirement for the exocyst was not limited to injury contexts as exocyst subunit RNAi eliminated dendrite regrowth after developmental pruning. We conclude that the exocyst is required for injury-induced and developmental neurite outgrowth, but that residual protein function can easily mask this requirement.
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Affiliation(s)
- Rachel D Swope
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - J Ian Hertzler
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Michelle C Stone
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Gregory O Kothe
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Melissa M Rolls
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA.
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17
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Wenzel EM, Elfmark LA, Stenmark H, Raiborg C. ER as master regulator of membrane trafficking and organelle function. J Cell Biol 2022; 221:213468. [PMID: 36108241 PMCID: PMC9481738 DOI: 10.1083/jcb.202205135] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/16/2022] [Accepted: 08/22/2022] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER), which occupies a large portion of the cytoplasm, is the cell’s main site for the biosynthesis of lipids and carbohydrate conjugates, and it is essential for folding, assembly, and biosynthetic transport of secreted proteins and integral membrane proteins. The discovery of abundant membrane contact sites (MCSs) between the ER and other membrane compartments has revealed that, in addition to its biosynthetic and secretory functions, the ER plays key roles in the regulation of organelle dynamics and functions. In this review, we will discuss how the ER regulates endosomes, lysosomes, autophagosomes, mitochondria, peroxisomes, and the Golgi apparatus via MCSs. Such regulation occurs via lipid and Ca2+ transfer and also via control of in trans dephosphorylation reactions and organelle motility, positioning, fusion, and fission. The diverse controls of other organelles via MCSs manifest the ER as master regulator of organelle biology.
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Affiliation(s)
- Eva Maria Wenzel
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
| | - Liv Anker Elfmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
| | - Camilla Raiborg
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
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18
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Costa AC, Sousa MM. The Role of Spastin in Axon Biology. Front Cell Dev Biol 2022; 10:934522. [PMID: 35865632 PMCID: PMC9294387 DOI: 10.3389/fcell.2022.934522] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/07/2022] [Indexed: 12/05/2022] Open
Abstract
Neurons are highly polarized cells with elaborate shapes that allow them to perform their function. In neurons, microtubule organization—length, density, and dynamics—are essential for the establishment of polarity, growth, and transport. A mounting body of evidence shows that modulation of the microtubule cytoskeleton by microtubule-associated proteins fine tunes key aspects of neuronal cell biology. In this respect, microtubule severing enzymes—spastin, katanin and fidgetin—a group of microtubule-associated proteins that bind to and generate internal breaks in the microtubule lattice, are emerging as key modulators of the microtubule cytoskeleton in different model systems. In this review, we provide an integrative view on the latest research demonstrating the key role of spastin in neurons, specifically in the context of axonal cell biology. We focus on the function of spastin in the regulation of microtubule organization, and axonal transport, that underlie its importance in the intricate control of axon growth, branching and regeneration.
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Affiliation(s)
- Ana Catarina Costa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
| | - Monica Mendes Sousa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
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19
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Sharif NA. Degeneration of retina-brain components and connections in glaucoma: Disease causation and treatment options for eyesight preservation. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100037. [PMID: 36685768 PMCID: PMC9846481 DOI: 10.1016/j.crneur.2022.100037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 03/30/2022] [Accepted: 04/01/2022] [Indexed: 01/25/2023] Open
Abstract
Eyesight is the most important of our sensory systems for optimal daily activities and overall survival. Patients who experience visual impairment due to elevated intraocular pressure (IOP) are often those afflicted with primary open-angle glaucoma (POAG) which slowly robs them of their vision unless treatment is administered soon after diagnosis. The hallmark features of POAG and other forms of glaucoma are damaged optic nerve, retinal ganglion cell (RGC) loss and atrophied RGC axons connecting to various brain regions associated with receipt of visual input from the eyes and eventual decoding and perception of images in the visual cortex. Even though increased IOP is the major risk factor for POAG, the disease is caused by many injurious chemicals and events that progress slowly within all components of the eye-brain visual axis. Lowering of IOP mitigates the damage to some extent with existing drugs, surgical and device implantation therapeutic interventions. However, since multifactorial degenerative processes occur during aging and with glaucomatous optic neuropathy, different forms of neuroprotective, nutraceutical and electroceutical regenerative and revitalizing agents and processes are being considered to combat these eye-brain disorders. These aspects form the basis of this short review article.
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Affiliation(s)
- Najam A. Sharif
- Duke-National University of Singapore Medical School, Singapore,Singapore Eye Research Institute (SERI), Singapore,Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, Texas, USA,Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX, USA,Department of Surgery & Cancer, Imperial College of Science and Technology, St. Mary's Campus, London, UK,Department of Pharmacy Sciences, School of School of Pharmacy and Health Professions, Creighton University, Omaha, NE, USA,Ophthalmology Innovation Center, Santen Incorporated, 6401 Hollis Street (Suite #125), Emeryville, CA, 94608, USA,Ophthalmology Innovation Center, Santen Incorporated, 6401 Hollis Street (Suite #125), Emeryville, CA, 94608, USA.
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20
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RSK1 promotes mammalian axon regeneration by inducing the synthesis of regeneration-related proteins. PLoS Biol 2022; 20:e3001653. [PMID: 35648763 PMCID: PMC9159620 DOI: 10.1371/journal.pbio.3001653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 04/28/2022] [Indexed: 12/04/2022] Open
Abstract
In contrast to the adult mammalian central nervous system (CNS), the neurons in the peripheral nervous system (PNS) can regenerate their axons. However, the underlying mechanism dictating the regeneration program after PNS injuries remains poorly understood. Combining chemical inhibitor screening with gain- and loss-of-function analyses, we identified p90 ribosomal S6 kinase 1 (RSK1) as a crucial regulator of axon regeneration in dorsal root ganglion (DRG) neurons after sciatic nerve injury (SNI). Mechanistically, RSK1 was found to preferentially regulate the synthesis of regeneration-related proteins using ribosomal profiling. Interestingly, RSK1 expression was up-regulated in injured DRG neurons, but not retinal ganglion cells (RGCs). Additionally, RSK1 overexpression enhanced phosphatase and tensin homolog (PTEN) deletion-induced axon regeneration in RGCs in the adult CNS. Our findings reveal a critical mechanism in inducing protein synthesis that promotes axon regeneration and further suggest RSK1 as a possible therapeutic target for neuronal injury repair. This study shows that p90 ribosomal S6 kinase 1 (RSK1) responds differentially to nerve injury in the peripheral and central nervous systems, and identifies it as a crucial regulator of axonal regeneration; mechanistically, RSK1 preferentially induces the synthesis of regeneration-related proteins via the RSK1-eEF2K-eEF2 axis.
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21
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Protrudin regulates FAK activation, endothelial cell migration and angiogenesis. Cell Mol Life Sci 2022; 79:220. [PMID: 35368213 PMCID: PMC8977271 DOI: 10.1007/s00018-022-04251-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/23/2022] [Accepted: 03/15/2022] [Indexed: 12/13/2022]
Abstract
During angiogenesis, endothelial cells form protrusive sprouts and migrate towards the angiogenic stimulus. In this study, we investigate the role of the endoplasmic reticulum (ER)-anchored protein, Protrudin, in endothelial cell protrusion, migration and angiogenesis. Our results demonstrate that Protrudin regulates angiogenic tube formation in primary endothelial cells, Human umbilical vein endothelial cells (HUVECs). Analysis of RNA sequencing data and its experimental validation revealed cell migration as a prominent cellular function affected in HUVECs subjected to Protrudin knockdown. Further, our results demonstrate that knockdown of Protrudin inhibits focal adhesion kinase (FAK) activation in HUVECs and human aortic endothelial cells (HAECs). This is associated with a loss of polarized phospho-FAK distribution upon Protrudin knockdown as compared to Protrudin expressing HUVECs. Reduction of Protrudin also results in a perinuclear accumulation of mTOR and a decrease in VEGF-mediated S6K activation. However, further experiments suggest that the observed inhibition of angiogenesis in Protrudin knockdown cells is not affected by mTOR disturbance. Therefore, our findings suggest that defects in FAK activation and its abnormal subcellular distribution upon Protrudin knockdown are associated with a detrimental effect on endothelial cell migration and angiogenesis. Furthermore, mice with global Protrudin deletion demonstrate reduced retinal vascular progression. To conclude, our results provide evidence for a novel key role of Protrudin in endothelial cell migration and angiogenesis.
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22
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Vargova I, Kriska J, Kwok JCF, Fawcett JW, Jendelova P. Long-Term Cultures of Spinal Cord Interneurons. Front Cell Neurosci 2022; 16:827628. [PMID: 35197829 PMCID: PMC8859857 DOI: 10.3389/fncel.2022.827628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/12/2022] [Indexed: 11/25/2022] Open
Abstract
Spinal cord interneurons (SpINs) are highly diverse population of neurons that play a significant role in circuit reorganization and spontaneous recovery after spinal cord injury. Regeneration of SpIN axons across rodent spinal injuries has been demonstrated after modification of the environment and neurotrophin treatment, but development of methods to enhance the intrinsic regenerative ability of SpINs is needed. There is a lack of described in vitro models of spinal cord neurons in which to develop new regeneration treatments. For this reason, we developed a new model of mouse primary spinal cord neuronal culture in which to analyze maturation, morphology, physiology, connectivity and regeneration of identified interneurons. Isolated from E14 mice, the neurons mature over 15 days in vitro, demonstrated by expression of maturity markers, electrophysiological patch-clamp recordings, and formation of synapses. The neurons express markers of SpINs, including Tlx3, Lmx1b, Lbx1, Chx10, and Pax2. The neurons demonstrate distinct morphologies and some form perineuronal nets in long-term cultivation. Live neurons in various maturation stages were axotomized, using a 900 nm multiphoton laser and their fate was observed overnight. The percentage of axons that regenerated declined with neuronal maturity. This model of SpINs will be a valuable tool in future regenerative, developmental, and functional studies alongside existing models using cortical or hippocampal neurons.
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Affiliation(s)
- Ingrid Vargova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Jessica C. F. Kwok
- The Center for Reconstructive Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - James W. Fawcett
- The Center for Reconstructive Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Pavla Jendelova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
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23
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Nakamura T, Koinuma S. TC10 as an essential molecule in axon regeneration through membrane supply and microtubule stabilization. Neural Regen Res 2022; 17:87-88. [PMID: 34100433 PMCID: PMC8451582 DOI: 10.4103/1673-5374.314297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Takeshi Nakamura
- Division of Cell Signaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Japan
| | - Shingo Koinuma
- Division of Cell Signaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Japan
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24
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Kors S, Costello JL, Schrader M. VAP Proteins - From Organelle Tethers to Pathogenic Host Interactors and Their Role in Neuronal Disease. Front Cell Dev Biol 2022; 10:895856. [PMID: 35756994 PMCID: PMC9213790 DOI: 10.3389/fcell.2022.895856] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/25/2022] [Indexed: 12/26/2022] Open
Abstract
Vesicle-associated membrane protein (VAMP)-associated proteins (VAPs) are ubiquitous ER-resident tail-anchored membrane proteins in eukaryotic cells. Their N-terminal major sperm protein (MSP) domain faces the cytosol and allows them to interact with a wide variety of cellular proteins. Therefore, VAP proteins are vital to many cellular processes, including organelle membrane tethering, lipid transfer, autophagy, ion homeostasis and viral defence. Here, we provide a timely overview of the increasing number of VAPA/B binding partners and discuss the role of VAPA/B in maintaining organelle-ER interactions and cooperation. Furthermore, we address how viruses and intracellular bacteria hijack VAPs and their binding partners to induce interactions between the host ER and pathogen-containing compartments and support pathogen replication. Finally, we focus on the role of VAP in human disease and discuss how mutated VAPB leads to the disruption of cellular homeostasis and causes amyotrophic lateral sclerosis.
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Affiliation(s)
- Suzan Kors
- *Correspondence: Suzan Kors, ; Michael Schrader,
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25
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Ching J, Osborne A, Eva R, Prudent J, Yu-Wai-Man P. Quantifying inter-organelle membrane contact sites using proximity ligation assay in fixed optic nerve sections. Exp Eye Res 2021; 213:108793. [PMID: 34656549 PMCID: PMC8683748 DOI: 10.1016/j.exer.2021.108793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 10/02/2021] [Accepted: 10/12/2021] [Indexed: 10/25/2022]
Abstract
Membrane contact sites (MCS) play crucial roles in cell physiology with dysfunction in several MCS proteins being linked with neurological and optic nerve diseases. Although there have been significant advances in imaging these interactions over the past two decades with advanced electron microscopy techniques, super-resolution imaging and proximity-dependent fluorescent reporters, a technique to observe and quantify MCS in mammalian optic nerve tissues has not yet been reported. We demonstrate for the first time that proximity ligation assay (PLA), a technique already used in mammalian cell lines, can be used as an efficient method of quantifying inter-organelle contact sites, namely mitochondria-endoplasmic reticulum (ER) and mitochondria-late-endosomes, in mammalian optic nerve tissues treated with adeno-associated virus (AAV) gene therapy with wild-type or phosphomimetic (active) protrudin. PLA utilises complementary single-stranded DNA oligomers bound to secondary antibodies that hybridise and complete a circular piece of DNA when the primary antibodies of interest interact. These interactions can be detected by amplifying the circular DNA and adding fluorescent probes. We show that PLA is a useful method that can be used to quantify MCS in optic nerve tissues. We have found that upregulation of protrudin with gene therapy significantly increases the number of mitochondria-ER and mitochondria-Rab7-late endosomes contact sites in optic nerves.
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Affiliation(s)
- Jared Ching
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK; Department of Ophthalmology, Addenbrooke's Hospital, Cambridge, UK.
| | - Andrew Osborne
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Ikarovec Ltd, Norwich Innovation Centre, Norwich, UK
| | - Richard Eva
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Patrick Yu-Wai-Man
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK; Department of Ophthalmology, Addenbrooke's Hospital, Cambridge, UK; Moorfields Eye Hospital, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
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Nieuwenhuis B, Eva R. Promoting axon regeneration in the central nervous system by increasing PI3-kinase signaling. Neural Regen Res 2021; 17:1172-1182. [PMID: 34782551 PMCID: PMC8643051 DOI: 10.4103/1673-5374.327324] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous system. Axons in the central nervous system fail to regenerate, meaning that injuries or diseases that cause loss of axonal connectivity have life-changing consequences. In 2008, genetic deletion of PTEN was identified as a means of stimulating robust regeneration in the optic nerve. PTEN is a phosphatase that opposes the actions of PI3-kinase, a family of enzymes that function to generate the membrane phospholipid PIP3 from PIP2 (phosphatidylinositol (3,4,5)-trisphosphate from phosphatidylinositol (4,5)-bisphosphate). Deletion of PTEN therefore allows elevated signaling downstream of PI3-kinase, and was initially demonstrated to promote axon regeneration by signaling through mTOR. More recently, additional mechanisms have been identified that contribute to the neuron-intrinsic control of regenerative ability. This review describes neuronal signaling pathways downstream of PI3-kinase and PIP3, and considers them in relation to both developmental and regenerative axon growth. We briefly discuss the key neuron-intrinsic mechanisms that govern regenerative ability, and describe how these are affected by signaling through PI3-kinase. We highlight the recent finding of a developmental decline in the generation of PIP3 as a key reason for regenerative failure, and summarize the studies that target an increase in signaling downstream of PI3-kinase to facilitate regeneration in the adult central nervous system. Finally, we discuss obstacles that remain to be overcome in order to generate a robust strategy for repairing the injured central nervous system through manipulation of PI3-kinase signaling.
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Affiliation(s)
- Bart Nieuwenhuis
- John van Geest Center for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Richard Eva
- John van Geest Center for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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Bodakuntla S, Nedozralova H, Basnet N, Mizuno N. Cytoskeleton and Membrane Organization at Axon Branches. Front Cell Dev Biol 2021; 9:707486. [PMID: 34540830 PMCID: PMC8440873 DOI: 10.3389/fcell.2021.707486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/06/2021] [Indexed: 11/13/2022] Open
Abstract
Axon branching is a critical process ensuring a high degree of interconnectivity for neural network formation. As branching occurs at sites distant from the soma, it is necessary that axons have a local system to dynamically control and regulate axonal growth. This machinery depends on the orchestration of cellular functions such as cytoskeleton, subcellular transport, energy production, protein- and membrane synthesis that are adapted for branch formation. Compared to the axon shaft, branching sites show a distinct and dynamic arrangement of cytoskeleton components, endoplasmic reticulum and mitochondria. This review discusses the regulation of axon branching in the context of cytoskeleton and membrane remodeling.
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Affiliation(s)
- Satish Bodakuntla
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Hana Nedozralova
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Nirakar Basnet
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Naoko Mizuno
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States.,National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, United States
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28
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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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29
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Venditti R, Wilson C, De Matteis MA. Regulation and physiology of membrane contact sites. Curr Opin Cell Biol 2021; 71:148-157. [PMID: 33932623 DOI: 10.1016/j.ceb.2021.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/18/2021] [Accepted: 03/22/2021] [Indexed: 12/14/2022]
Abstract
Membrane contact sites (MCSs) in addition to impacting the functions of membrane-limited organelles also have a role in the spatial and functional organization of cells, tissues and whole organisms. MCSs have been identified between all organelles and the identification of their molecular composition has progressed significantly in recent years. Equally important is how MCSs respond dynamically to physiological stimuli, how this is regulated, and the physiological roles of MCSs in tissues and at the organismal level, an area that still remains relatively unexplored. In the present review, we focus on the regulation of MCSs, considerations of their function at the organismal level, and how mutations of MCS components linked to genetic diseases might inform us about their physiological relevance.
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Affiliation(s)
- Rossella Venditti
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Molecular Medicine and Medical Biotechnology, University of Napoli Federico II-Medical School, Naples, Italy
| | - Cathal Wilson
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Maria Antonietta De Matteis
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Molecular Medicine and Medical Biotechnology, University of Napoli Federico II-Medical School, Naples, Italy.
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Abstract
Our cells are comprised of billions of proteins, lipids, and other small molecules packed into their respective subcellular organelles, with the daunting task of maintaining cellular homeostasis over a lifetime. However, it is becoming increasingly evident that organelles do not act as autonomous discrete units but rather as interconnected hubs that engage in extensive communication through membrane contacts. In the last few years, our understanding of how these contacts coordinate organelle function has redefined our view of the cell. This review aims to present novel findings on the cellular interorganelle communication network and how its dysfunction may contribute to aging and neurodegeneration. The consequences of disturbed interorganellar communication are intimately linked with age-related pathologies. Given that both aging and neurodegenerative diseases are characterized by the concomitant failure of multiple cellular pathways, coordination of organelle communication and function could represent an emerging regulatory mechanism critical for long-term cellular homeostasis. We anticipate that defining the relationships between interorganelle communication, aging, and neurodegeneration will open new avenues for therapeutics.
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Affiliation(s)
- Maja Petkovic
- Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA
| | - Caitlin E O'Brien
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Yuh Nung Jan
- Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
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Axonal Organelles as Molecular Platforms for Axon Growth and Regeneration after Injury. Int J Mol Sci 2021; 22:ijms22041798. [PMID: 33670312 PMCID: PMC7918155 DOI: 10.3390/ijms22041798] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Investigating the molecular mechanisms governing developmental axon growth has been a useful approach for identifying new strategies for boosting axon regeneration after injury, with the goal of treating debilitating conditions such as spinal cord injury and vision loss. The picture emerging is that various axonal organelles are important centers for organizing the molecular mechanisms and machinery required for growth cone development and axon extension, and these have recently been targeted to stimulate robust regeneration in the injured adult central nervous system (CNS). This review summarizes recent literature highlighting a central role for organelles such as recycling endosomes, the endoplasmic reticulum, mitochondria, lysosomes, autophagosomes and the proteasome in developmental axon growth, and describes how these organelles can be targeted to promote axon regeneration after injury to the adult CNS. This review also examines the connections between these organelles in developing and regenerating axons, and finally discusses the molecular mechanisms within the axon that are required for successful axon growth.
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Ewan EE, Avraham O, Carlin D, Gonçalves TM, Zhao G, Cavalli V. Ascending dorsal column sensory neurons respond to spinal cord injury and downregulate genes related to lipid metabolism. Sci Rep 2021; 11:374. [PMID: 33431991 PMCID: PMC7801468 DOI: 10.1038/s41598-020-79624-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 12/07/2020] [Indexed: 02/08/2023] Open
Abstract
Regeneration failure after spinal cord injury (SCI) results in part from the lack of a pro-regenerative response in injured neurons, but the response to SCI has not been examined specifically in injured sensory neurons. Using RNA sequencing of dorsal root ganglion, we determined that thoracic SCI elicits a transcriptional response distinct from sciatic nerve injury (SNI). Both SNI and SCI induced upregulation of ATF3 and Jun, yet this response failed to promote growth in sensory neurons after SCI. RNA sequencing of purified sensory neurons one and three days after injury revealed that unlike SNI, the SCI response is not sustained. Both SCI and SNI elicited the expression of ATF3 target genes, with very little overlap between conditions. Pathway analysis of differentially expressed ATF3 target genes revealed that fatty acid biosynthesis and terpenoid backbone synthesis were downregulated after SCI but not SNI. Pharmacologic inhibition of fatty acid synthase, the enzyme generating palmitic acid, decreased axon growth and regeneration in vitro. These results support the notion that decreased expression of lipid metabolism-related genes after SCI, including fatty acid synthase, may restrict axon regenerative capacity after SCI.
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Affiliation(s)
- Eric E Ewan
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Oshri Avraham
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Dan Carlin
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Tassia Mangetti Gonçalves
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Guoyan Zhao
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, USA
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8108, St. Louis, MO, 63110-1093, 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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Rahić O, Tucak A, Omerović N, Sirbubalo M, Hindija L, Hadžiabdić J, Vranić E. Novel Drug Delivery Systems Fighting Glaucoma: Formulation Obstacles and Solutions. Pharmaceutics 2020; 13:E28. [PMID: 33375224 PMCID: PMC7824381 DOI: 10.3390/pharmaceutics13010028] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/19/2020] [Accepted: 12/22/2020] [Indexed: 02/06/2023] Open
Abstract
Glaucoma is considered to be one of the biggest health problems in the world. It is the main cause of preventable blindness due to its asymptomatic nature in the early stages on the one hand and patients' non-adherence on the other. There are several approaches in glaucoma treatment, whereby this has to be individually designed for each patient. The first-line treatment is medication therapy. However, taking into account numerous disadvantages of conventional ophthalmic dosage forms, intensive work has been carried out on the development of novel drug delivery systems for glaucoma. This review aims to provide an overview of formulation solutions and strategies in the development of in situ gel systems, nanosystems, ocular inserts, contact lenses, collagen corneal shields, ocular implants, microneedles, and iontophoretic devices. The results of studies confirming the effectiveness of the aforementioned drug delivery systems were also briefly presented.
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Affiliation(s)
- Ognjenka Rahić
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina; (A.T.); (M.S.); (L.H.); (J.H.)
| | - Amina Tucak
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina; (A.T.); (M.S.); (L.H.); (J.H.)
| | - Naida Omerović
- Department of Clinical Pharmacy, Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina;
| | - Merima Sirbubalo
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina; (A.T.); (M.S.); (L.H.); (J.H.)
| | - Lamija Hindija
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina; (A.T.); (M.S.); (L.H.); (J.H.)
| | - Jasmina Hadžiabdić
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina; (A.T.); (M.S.); (L.H.); (J.H.)
| | - Edina Vranić
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Sarajevo, Zmaja od Bosne 8, 71000 Sarajevo, Bosnia and Herzegovina; (A.T.); (M.S.); (L.H.); (J.H.)
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