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Hosen S, Ikeda-Yorifuji I, Yamashita T. Asporin and CD109, expressed in the injured neonatal spinal cord, attenuate axonal re-growth in vitro. Neurosci Lett 2024; 833:137832. [PMID: 38796094 DOI: 10.1016/j.neulet.2024.137832] [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: 01/26/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
Axonal regeneration is restricted in adults and causes irreversible motor dysfunction following spinal cord injury (SCI). In contrast, neonates have prominent regenerative potential and can restore their neural function. Although the distinct cellular responses in neonates have been studied, how they contribute to neural recovery remains unclear. To assess whether the secreted molecules in neonatal SCI can enhance neural regeneration, we re-analyzed the previously performed single-nucleus RNA-seq (snRNA-seq) and focused on Asporin and Cd109, the highly expressed genes in the injured neonatal spinal cord. In the present study, we showed that both these molecules were expressed in the injured spinal cords of adults and neonates. We treated the cortical neurons with recombinant Asporin or CD109 to observe their direct effects on neurons in vitro. We demonstrated that these molecules enhance neurite outgrowth in neurons. However, these molecules did not enhance re-growth of severed axons. Our results suggest that Asporin and CD109 influence neurites at the lesion site, rather than promoting axon regeneration, to restore neural function in neonates after SCI.
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Affiliation(s)
- Sakura Hosen
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Iyo Ikeda-Yorifuji
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan; WPI Immunology Frontier Research Center, Osaka University, Suita, Japan; Department of Molecular Neuroscience, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan; Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Japan.
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Guo Y, Sun Y, Ma M, Huang Y, Zhang S, Tian Q. Djsnon, a downstream gene of Djfoxk1, is required for the regeneration of the planarian central nervous system. Biochem Biophys Res Commun 2023; 643:8-15. [PMID: 36584589 DOI: 10.1016/j.bbrc.2022.12.074] [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] [Accepted: 12/23/2022] [Indexed: 12/25/2022]
Abstract
Regulators of adult neurogenesis are crucial targets for neuronal repair. Freshwater planarians are ideal model systems for studying neuronal regeneration as they can regenerate their entire central nervous system (CNS) using pluripotent adult stem cells. Here, we identified Djfoxk1 in planarian Dugesia japonica to be required for planarian CNS regeneration. Knockdown of Djfoxk1 inhibits the regeneration of the cephalic ganglia, resulting in the failure of eye regeneration. By RNAi screening of Djfoxk1 downstream genes, we identified Djsnon as another regulator of planarian neuronal regeneration. Inhibition of Djsnon with RNA interference (RNAi) results in similar phenotypes caused by Djfoxk1 RNAi without affecting cell proliferation and wound healing. Our findings show that Djsnon as a downstream gene of Djfoxk1 regulates the regeneration of the planarian CNS.
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Affiliation(s)
- Yajun Guo
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Yujia Sun
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Mengwen Ma
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Yongding Huang
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Shoutao Zhang
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China; Longhu Laboratory of Advanced Immunology, Zhengzhou, Henan, China.
| | - Qingnan Tian
- School of LifeSciences, Zhengzhou University, Zhengzhou, Henan, China.
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TGFβ1 Induces Axonal Outgrowth via ALK5/PKA/SMURF1-Mediated Degradation of RhoA and Stabilization of PAR6. eNeuro 2020; 7:ENEURO.0104-20.2020. [PMID: 32887692 PMCID: PMC7540929 DOI: 10.1523/eneuro.0104-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/21/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022] Open
Abstract
Transforming growth factor (TGF)β1 has repeatedly been associated with axonal regeneration and recovery after injury to the CNS. We found TGFβ1 upregulated in the stroke-denervated mouse spinal cord after ischemic injury to the motor cortex as early as 4 d postinjury (dpi) and persisting up to 28 dpi. Given the potential role of TGFβ1 in structural plasticity and functional recovery after stroke highlighted in several published studies, we investigated its downstream signaling in an in vitro model of neurite outgrowth. We found that in this model, TGFβ1 rescues neurite outgrowth under growth inhibitory conditions via the canonical TGFβR2/ALK5 signaling axis. Thereby, protein kinase A (PKA)-mediated phosphorylation of the E3 ubiquitin ligase SMURF1 induces a switch of its substrate preference from PAR6 to the Ras homolog A (RhoA), in this way enhancing outgrowth on the level of the cytoskeleton. This proposed mechanism of TGFβ1 signaling could underly the observed increase in structural plasticity after stroke in vivo as suggested by the temporal and spatial expression of TGFβ1. In accordance with previous publications, this study corroborates the potential of TGFβ1 and associated signaling cascades as a target for future therapeutic interventions to enhance structural plasticity and functional recovery for stroke patients.
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Tecalco-Cruz AC, Ríos-López DG, Vázquez-Victorio G, Rosales-Alvarez RE, Macías-Silva M. Transcriptional cofactors Ski and SnoN are major regulators of the TGF-β/Smad signaling pathway in health and disease. Signal Transduct Target Ther 2018; 3:15. [PMID: 29892481 PMCID: PMC5992185 DOI: 10.1038/s41392-018-0015-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 02/16/2018] [Accepted: 03/15/2018] [Indexed: 12/19/2022] Open
Abstract
The transforming growth factor-β (TGF-β) family plays major pleiotropic roles by regulating many physiological processes in development and tissue homeostasis. The TGF-β signaling pathway outcome relies on the control of the spatial and temporal expression of >500 genes, which depend on the functions of the Smad protein along with those of diverse modulators of this signaling pathway, such as transcriptional factors and cofactors. Ski (Sloan-Kettering Institute) and SnoN (Ski novel) are Smad-interacting proteins that negatively regulate the TGF-β signaling pathway by disrupting the formation of R-Smad/Smad4 complexes, as well as by inhibiting Smad association with the p300/CBP coactivators. The Ski and SnoN transcriptional cofactors recruit diverse corepressors and histone deacetylases to repress gene transcription. The TGF-β/Smad pathway and coregulators Ski and SnoN clearly regulate each other through several positive and negative feedback mechanisms. Thus, these cross-regulatory processes finely modify the TGF-β signaling outcome as they control the magnitude and duration of the TGF-β signals. As a result, any alteration in these regulatory mechanisms may lead to disease development. Therefore, the design of targeted therapies to exert tight control of the levels of negative modulators of the TGF-β pathway, such as Ski and SnoN, is critical to restore cell homeostasis under the specific pathological conditions in which these cofactors are deregulated, such as fibrosis and cancer. Proteins that repress molecular signaling through the transforming growth factor-beta (TGF-β) pathway offer promising targets for treating cancer and fibrosis. Marina Macías-Silva and colleagues from the National Autonomous University of Mexico in Mexico City review the ways in which a pair of proteins, called Ski and SnoN, interact with downstream mediators of TGF-β to inhibit the effects of this master growth factor. Aberrant levels of Ski and SnoN have been linked to diverse range of diseases involving cell proliferation run amok, and therapies that regulate the expression of these proteins could help normalize TGF-β signaling to healthier physiological levels. For decades, drug companies have tried to target the TGF-β pathway, with limited success. Altering the activity of these repressors instead could provide a roundabout way of remedying pathogenic TGF-β activity in fibrosis and oncology.
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Affiliation(s)
- Angeles C Tecalco-Cruz
- 1Instituto de Investigaciones Biomédicas at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | - Diana G Ríos-López
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | | | - Reyna E Rosales-Alvarez
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | - Marina Macías-Silva
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
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Abstract
In this review, Huang and Bonni discuss the functions and mechanisms of the anaphase-promoting complex in neurogenesis; glial differentiation and migration; neuronal survival, metabolism, and morphogenesis; synapse formation and plasticity; and learning and memory. Control of protein abundance by the ubiquitin–proteasome system is essential for normal brain development and function. Just over a decade ago, the first post-mitotic function of the anaphase-promoting complex, a major cell cycle-regulated E3 ubiquitin ligase, was discovered in the control of axon growth and patterning in the mammalian brain. Since then, a large number of studies have identified additional novel roles for the anaphase-promoting complex in diverse aspects of neuronal connectivity and plasticity in the developing and mature nervous system. In this review, we discuss the functions and mechanisms of the anaphase-promoting complex in neurogenesis, glial differentiation and migration, neuronal survival and metabolism, neuronal morphogenesis, synapse formation and plasticity, and learning and memory. We also provide a perspective on future investigations of the anaphase-promoting complex in neurobiology.
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Affiliation(s)
- Ju Huang
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Azad Bonni
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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van Niekerk EA, Tuszynski MH, Lu P, Dulin JN. Molecular and Cellular Mechanisms of Axonal Regeneration After Spinal Cord Injury. Mol Cell Proteomics 2015; 15:394-408. [PMID: 26695766 DOI: 10.1074/mcp.r115.053751] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 12/28/2022] Open
Abstract
Following axotomy, a complex temporal and spatial coordination of molecular events enables regeneration of the peripheral nerve. In contrast, multiple intrinsic and extrinsic factors contribute to the general failure of axonal regeneration in the central nervous system. In this review, we examine the current understanding of differences in protein expression and post-translational modifications, activation of signaling networks, and environmental cues that may underlie the divergent regenerative capacity of central and peripheral axons. We also highlight key experimental strategies to enhance axonal regeneration via modulation of intraneuronal signaling networks and the extracellular milieu. Finally, we explore potential applications of proteomics to fill gaps in the current understanding of molecular mechanisms underlying regeneration, and to provide insight into the development of more effective approaches to promote axonal regeneration following injury to the nervous system.
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Affiliation(s)
- Erna A van Niekerk
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093;
| | - Mark H Tuszynski
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093; §Veterans Administration Medical Center, San Diego, CA 92161
| | - Paul Lu
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093; §Veterans Administration Medical Center, San Diego, CA 92161
| | - Jennifer N Dulin
- From the ‡Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093
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Ma TC, Willis DE. What makes a RAG regeneration associated? Front Mol Neurosci 2015; 8:43. [PMID: 26300725 PMCID: PMC4528284 DOI: 10.3389/fnmol.2015.00043] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/24/2015] [Indexed: 12/31/2022] Open
Abstract
Regenerative failure remains a significant barrier for functional recovery after central nervous system (CNS) injury. As such, understanding the physiological processes that regulate axon regeneration is a central focus of regenerative medicine. Studying the gene transcription responses to axon injury of regeneration competent neurons, such as those of the peripheral nervous system (PNS), has provided insight into the genes associated with regeneration. Though several individual “regeneration-associated genes” (RAGs) have been identified from these studies, the response to injury likely regulates the expression of functionally coordinated and complementary gene groups. For instance, successful regeneration would require the induction of genes that drive the intrinsic growth capacity of neurons, while simultaneously downregulating the genes that convey environmental inhibitory cues. Thus, this view emphasizes the transcriptional regulation of gene “programs” that contribute to the overall goal of axonal regeneration. Here, we review the known RAGs, focusing on how their transcriptional regulation can reveal the underlying gene programs that drive a regenerative phenotype. Finally, we will discuss paradigms under which we can determine whether these genes are injury-associated, or indeed necessary for regeneration.
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Affiliation(s)
- Thong C Ma
- Department of Neurology, Columbia University New York, NY, USA
| | - Dianna E Willis
- Brain Mind Research Institute, Weill Cornell Medical College New York, NY, USA ; Burke-Cornell Medical Research Institute White Plains, NY, USA
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Abstract
Although neurons execute a cell intrinsic program of axonal growth during development, following the establishment of connections, the developmental growth capacity declines. Besides environmental challenges, this switch largely accounts for the failure of adult central nervous system (CNS) axons to regenerate. Here, we discuss the cell intrinsic control of axon regeneration, including not only the regulation of transcriptional and epigenetic mechanisms, but also the modulation of local protein translation, retrograde and anterograde axonal transport, and microtubule dynamics. We further explore the causes underlying the failure of CNS neurons to mount a vigorous regenerative response, and the paradigms demonstrating the activation of cell intrinsic axon growth programs. Finally, we present potential mechanisms to support axon regeneration, as these may represent future therapeutic approaches to promote recovery following CNS injury and disease.
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Affiliation(s)
- Fernando M Mar
- Nerve Regeneration Group Instituto de Biologia Molecular e Celular - IBMC University of Porto, Porto, Portugal
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The brake within: Mechanisms of intrinsic regulation of axon growth featuring the Cdh1-APC pathway. Transl Neurosci 2013. [DOI: 10.2478/s13380-013-0125-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractNeurons of the central nervous system (CNS) form a magnificent network destined to control bodily functions and human behavior for a lifetime. During development of the CNS, neurons extend axons that establish connections to other neurons. Axon growth is guided by extrinsic cues and guidance molecules. In addition to environmental signals, intrinsic programs including transcription and the ubiquitin proteasome system (UPS) have been implicated in axon growth regulation. Over the past few years it has become evident that the E3 ubiquitin ligase Cdh1-APC together with its associated pathway plays a central role in axon growth suppression. By elucidating the intricate interplay of extrinsic and intrinsic mechanisms, we can enhance our understanding of why axonal regeneration in the CNS fails and obtain further insight into how to stimulate successful regeneration after injury.
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