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Brüll M, Geese N, Celardo I, Laumann M, Leist M. Preparation of Viable Human Neurites for Neurobiological and Neurodegeneration Studies. Cells 2024; 13:242. [PMID: 38334634 PMCID: PMC10854604 DOI: 10.3390/cells13030242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024] Open
Abstract
Few models allow the study of neurite damage in the human central nervous system. We used here dopaminergic LUHMES neurons to establish a culture system that allows for (i) the observation of highly enriched neurites, (ii) the preparation of the neurite fraction for biochemical studies, and (iii) the measurement of neurite markers and metabolites after axotomy. LUHMES-based spheroids, plated in culture dishes, extended neurites of several thousand µm length, while all somata remained aggregated. These cultures allowed an easy microscopic observation of live or fixed neurites. Neurite-only cultures (NOC) were produced by cutting out the still-aggregated somata. The potential application of such cultures was exemplified by determinations of their protein and RNA contents. For instance, the mitochondrial TOM20 protein was highly abundant, while nuclear histone H3 was absent. Similarly, mitochondrial-encoded RNAs were found at relatively high levels, while the mRNA for a histone or the neuronal nuclear marker NeuN (RBFOX3) were relatively depleted in NOC. Another potential use of NOC is the study of neurite degeneration. For this purpose, an algorithm to quantify neurite integrity was developed. Using this tool, we found that the addition of nicotinamide drastically reduced neurite degeneration. Also, the chelation of Ca2+ in NOC delayed the degeneration, while inhibitors of calpains had no effect. Thus, NOC proved to be suitable for biochemical analysis and for studying degeneration processes after a defined cut injury.
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Affiliation(s)
- Markus Brüll
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457 Konstanz, Germany; (M.B.); (N.G.); (I.C.)
| | - Nils Geese
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457 Konstanz, Germany; (M.B.); (N.G.); (I.C.)
| | - Ivana Celardo
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457 Konstanz, Germany; (M.B.); (N.G.); (I.C.)
| | - Michael Laumann
- Electron Microscopy Centre, University of Konstanz, 78457 Konstanz, Germany;
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, 78457 Konstanz, Germany; (M.B.); (N.G.); (I.C.)
- Center for Alternatives to Animal Testing in Europe (CAAT-Europe), University of Konstanz, 78457 Konstanz, Germany
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Jeon Y, Shin YK, Kim H, Choi YY, Kang M, Kwon Y, Cho Y, Chi SW, Shin JE. βPix Guanine Nucleotide Exchange Factor Regulates Regeneration of Injured Peripheral Axons. Int J Mol Sci 2023; 24:14357. [PMID: 37762659 PMCID: PMC10532151 DOI: 10.3390/ijms241814357] [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: 07/29/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
Axon regeneration is essential for successful recovery after peripheral nerve injury. Although growth cone reformation and axonal extension are crucial steps in axonal regeneration, the regulatory mechanisms underlying these dynamic processes are poorly understood. Here, we identify βPix (Arhgef7), the guanine nucleotide exchange factor for Rac1 GTPase, as a regulator of axonal regeneration. After sciatic nerve injury in mice, the expression levels of βPix increase significantly in nerve segments containing regenerating axons. In regrowing axons, βPix is localized in the peripheral domain of the growth cone. Using βPix neuronal isoform knockout (NIKO) mice in which the neuronal isoforms of βPix are specifically removed, we demonstrate that βPix promotes neurite outgrowth in cultured dorsal root ganglion neurons and in vivo axon regeneration after sciatic nerve crush injury. Activation of cJun and STAT3 in the cell bodies is not affected in βPix NIKO mice, supporting the local action of βPix in regenerating axons. Finally, inhibiting Src, a kinase previously identified as an activator of the βPix neuronal isoform, causes axon outgrowth defects in vitro, like those found in the βPix NIKO neurons. Altogether, these data indicate that βPix plays an important role in axonal regrowth during peripheral nerve regeneration.
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Affiliation(s)
- Yewon Jeon
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea;
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience, College of Medicine, Dong-A University, Busan 49201, Republic of Korea; (Y.K.S.); (H.K.); (Y.Y.C.); (M.K.)
| | - Yoon Kyung Shin
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience, College of Medicine, Dong-A University, Busan 49201, Republic of Korea; (Y.K.S.); (H.K.); (Y.Y.C.); (M.K.)
| | - Hwigyeong Kim
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience, College of Medicine, Dong-A University, Busan 49201, Republic of Korea; (Y.K.S.); (H.K.); (Y.Y.C.); (M.K.)
- Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan 49201, Republic of Korea
| | - Yun Young Choi
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience, College of Medicine, Dong-A University, Busan 49201, Republic of Korea; (Y.K.S.); (H.K.); (Y.Y.C.); (M.K.)
| | - Minjae Kang
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience, College of Medicine, Dong-A University, Busan 49201, Republic of Korea; (Y.K.S.); (H.K.); (Y.Y.C.); (M.K.)
- Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan 49201, Republic of Korea
| | - Younghee Kwon
- Department School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Yongcheol Cho
- Department of Brain Sciences, DGIST, Daegu 42899, Republic of Korea;
| | - Sung Wook Chi
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea;
| | - Jung Eun Shin
- Peripheral Neuropathy Research Center (PNRC), Department of Molecular Neuroscience, College of Medicine, Dong-A University, Busan 49201, Republic of Korea; (Y.K.S.); (H.K.); (Y.Y.C.); (M.K.)
- Department of Translational Biomedical Sciences, Graduate School of Dong-A University, Busan 49201, Republic of Korea
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Moon C. New Insights into and Emerging Roles of Animal Models for Neurological Disorders. Int J Mol Sci 2022; 23:ijms23094957. [PMID: 35563352 PMCID: PMC9105220 DOI: 10.3390/ijms23094957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 04/28/2022] [Indexed: 12/01/2022] Open
Affiliation(s)
- Changjong Moon
- Department of Veterinary Anatomy and Animal Behavior, College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju 61186, Korea
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Varier P, Raju G, Madhusudanan P, Jerard C, Shankarappa SA. A Brief Review of In Vitro Models for Injury and Regeneration in the Peripheral Nervous System. Int J Mol Sci 2022; 23:816. [PMID: 35055003 PMCID: PMC8775373 DOI: 10.3390/ijms23020816] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/03/2021] [Accepted: 12/05/2021] [Indexed: 02/06/2023] Open
Abstract
Nerve axonal injury and associated cellular mechanisms leading to peripheral nerve damage are important topics of research necessary for reducing disability and enhancing quality of life. Model systems that mimic the biological changes that occur during human nerve injury are crucial for the identification of cellular responses, screening of novel therapeutic molecules, and design of neural regeneration strategies. In addition to in vivo and mathematical models, in vitro axonal injury models provide a simple, robust, and reductionist platform to partially understand nerve injury pathogenesis and regeneration. In recent years, there have been several advances related to in vitro techniques that focus on the utilization of custom-fabricated cell culture chambers, microfluidic chamber systems, and injury techniques such as laser ablation and axonal stretching. These developments seem to reflect a gradual and natural progression towards understanding molecular and signaling events at an individual axon and neuronal-soma level. In this review, we attempt to categorize and discuss various in vitro models of injury relevant to the peripheral nervous system and highlight their strengths, weaknesses, and opportunities. Such models will help to recreate the post-injury microenvironment and aid in the development of therapeutic strategies that can accelerate nerve repair.
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Affiliation(s)
| | | | | | | | - Sahadev A. Shankarappa
- Centre for Nanosciences & Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham, Kochi 682041, India; (P.V.); (G.R.); (P.M.); (C.J.)
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