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Mayer J, Krug C, Saller M, Feuchtinger A, Giunta R, Volkmer E, Holzbach T. Hypoxic pre-conditioned adipose-derived stem/progenitor cells embedded in fibrin conduits promote peripheral nerve regeneration in a sciatic nerve graft model. Neural Regen Res 2023; 18:652-656. [DOI: 10.4103/1673-5374.346464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Modelling and Refining Neuronal Circuits with Guidance Cues: Involvement of Semaphorins. Int J Mol Sci 2021; 22:ijms22116111. [PMID: 34204060 PMCID: PMC8201269 DOI: 10.3390/ijms22116111] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/17/2022] Open
Abstract
The establishment of neuronal circuits requires neurons to develop and maintain appropriate connections with cellular partners in and out the central nervous system. These phenomena include elaboration of dendritic arborization and formation of synaptic contacts, initially made in excess. Subsequently, refinement occurs, and pruning takes places both at axonal and synaptic level, defining a homeostatic balance maintained throughout the lifespan. All these events require genetic regulations which happens cell-autonomously and are strongly influenced by environmental factors. This review aims to discuss the involvement of guidance cues from the Semaphorin family.
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Shadrach JL, Pierchala BA. Semaphorin3A Signaling Is Dispensable for Motor Axon Reinnervation of the Adult Neuromuscular Junction. eNeuro 2018; 5:ENEURO.0155-17.2018. [PMID: 29774231 PMCID: PMC5955010 DOI: 10.1523/eneuro.0155-17.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 04/23/2018] [Accepted: 04/27/2018] [Indexed: 01/13/2023] Open
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that is formed by motor axon innervation of skeletal muscle fibers. The maintenance of motor-muscle connectivity is critical for the preservation of muscle tone and generation of movement. Injury can induce a robust regenerative response in motor axons, but severe trauma or chronic denervation resulting from neurodegenerative disease typically leads to inefficient repair and poor functional recovery. The axon guidance molecule Semaphorin3A (Sema3A) has been implicated as a negative regulator of motor innervation. Upon binding to a plexinA-neuropilin1 (Npn1) receptor complex, Sema3A initiates a downstream signaling cascade that results in axonal repulsion. Here, we established a reproducible nerve crush model to quantify motor nerve regeneration. We then used that model to investigate the role of Sema3A signaling at the adult NMJ. In contrast to previous findings, we found that Sema3A and Npn1 mRNA decrease in response to denervation, suggesting that Sema3A-Npn1 signaling may regulate NMJ reinnervation. To directly test that hypothesis, we used inducible knockout models to ubiquitously delete Sema3A or Npn1 from adult mice. Despite demonstrating that we could achieve highly efficient gene deletion, disruption of Sema3A-Npn1 signaling did not affect the normal maintenance of the NMJ or disrupt motor axon reinnervation after a denervating injury.
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Affiliation(s)
- Jennifer L. Shadrach
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109
- Program in Cellular and Molecular Biology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109
| | - Brian A. Pierchala
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109
- Program in Cellular and Molecular Biology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109
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Saller MM, Huettl RE, Mayer JM, Feuchtinger A, Krug C, Holzbach T, Volkmer E. Validation of a novel animal model for sciatic nerve repair with an adipose-derived stem cell loaded fibrin conduit. Neural Regen Res 2018; 13:854-861. [PMID: 29863016 PMCID: PMC5998632 DOI: 10.4103/1673-5374.232481] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Despite the regenerative capabilities of peripheral nerves, severe injuries or neuronal trauma of critical size impose immense hurdles for proper restoration of neuro-muscular circuitry. Autologous nerve grafts improve re-establishment of connectivity, but also comprise substantial donor site morbidity. We developed a rat model which allows the testing of different cell applications, i.e., mesenchymal stem cells, to improve nerve regeneration in vivo. To mimic inaccurate alignment of autologous nerve grafts with the injured nerve, a 20 mm portion of the sciatic nerve was excised, and sutured back in place in reversed direction. To validate the feasibility of our novel model, a fibrin gel conduit containing autologous undifferentiated adipose-derived stem cells was applied around the coaptation sites and compared to autologous nerve grafts. After evaluating sciatic nerve function for 16 weeks postoperatively, animals were sacrificed, and gastrocnemius muscle weight was determined along with morphological parameters (g-ratio, axon density & diameter) of regenerating axons. Interestingly, the addition of undifferentiated adipose-derived stem cells resulted in a significantly improved re-myelination, axon ingrowth and functional outcome, when compared to animals without a cell seeded conduit. The presented model thus displays several intriguing features: it imitates a certain mismatch in size, distribution and orientation of axons within the nerve coaptation site. The fibrin conduit itself allows for an easy application of cells and, as a true critical-size defect model, any observed improvement relates directly to the performed intervention. Since fibrin and adipose-derived stem cells have been approved for human applications, the technique can theoretically be performed on humans. Thus, we suggest that the model is a powerful tool to investigate cell mediated assistance of peripheral nerve regeneration.
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Affiliation(s)
- Maximilian M Saller
- Experimental Surgery and Regenerative Medicine (ExperiMed), Department of General, Trauma and Reconstructive Surgery, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Rosa-Eva Huettl
- Max-Planck-Institute of Psychiatry, Department of Stress Neurobiology and Neurogenetics, Munich, Germany
| | - Julius M Mayer
- Experimental Surgery and Regenerative Medicine (ExperiMed), Department of General, Trauma and Reconstructive Surgery, Ludwig-Maximilians-University (LMU); Department of Hand-, Plastic- and Aesthetic Surgery, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Annette Feuchtinger
- Research Unit Analytical Pathology, Munich, Helmholtz Zentrum Muenchen-German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Christian Krug
- Department of Hand-, Plastic- and Aesthetic Surgery, Ludwig-Maximilians-University (LMU), Munich, Germany; Department of Hand and Plastic Surgery, Spital Thurgau AG, Frauenfeld, Switzerland
| | - Thomas Holzbach
- Department of Hand-, Plastic- and Aesthetic Surgery, Ludwig-Maximilians-University (LMU), Munich, Germany; Department of Hand and Plastic Surgery, Spital Thurgau AG, Frauenfeld, Switzerland
| | - Elias Volkmer
- Experimental Surgery and Regenerative Medicine (ExperiMed), Department of General, Trauma and Reconstructive Surgery, Ludwig-Maximilians-University (LMU); Department of Hand-, Plastic- and Aesthetic Surgery, Ludwig-Maximilians-University (LMU), Munich, Germany
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Neuropilin 1 sequestration by neuropathogenic mutant glycyl-tRNA synthetase is permissive to vascular homeostasis. Sci Rep 2017; 7:9216. [PMID: 28835631 PMCID: PMC5569042 DOI: 10.1038/s41598-017-10005-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/27/2017] [Indexed: 12/11/2022] Open
Abstract
The mechanism by which dominantly inherited mutations in the housekeeping gene GARS, which encodes glycyl-tRNA synthetase (GlyRS), mediate selective peripheral nerve toxicity resulting in Charcot-Marie-Tooth disease type 2D (CMT2D) is still largely unresolved. The transmembrane receptor protein neuropilin 1 (Nrp1) was recently identified as an aberrant extracellular binding partner of mutant GlyRS. Formation of the Nrp1/mutant GlyRS complex antagonises Nrp1 interaction with one of its main natural ligands, vascular endothelial growth factor-A (VEGF-A), contributing to neurodegeneration. However, reduced extracellular binding of VEGF-A to Nrp1 is known to disrupt post-natal blood vessel development and growth. We therefore analysed the vascular system at early and late symptomatic time points in CMT2D mouse muscles, retina, and sciatic nerve, as well as in embryonic hindbrain. Mutant tissues show no difference in blood vessel diameter, density/growth, and branching from embryonic development to three months, spanning the duration over which numerous sensory and neuromuscular phenotypes manifest. Our findings indicate that mutant GlyRS-mediated disruption of Nrp1/VEGF-A signalling is permissive to maturation and maintenance of the vasculature in CMT2D mice.
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Himmels P, Paredes I, Adler H, Karakatsani A, Luck R, Marti HH, Ermakova O, Rempel E, Stoeckli ET, Ruiz de Almodóvar C. Motor neurons control blood vessel patterning in the developing spinal cord. Nat Commun 2017; 8:14583. [PMID: 28262664 PMCID: PMC5343469 DOI: 10.1038/ncomms14583] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 01/13/2017] [Indexed: 12/16/2022] Open
Abstract
Formation of a precise vascular network within the central nervous system is of critical importance to assure delivery of oxygen and nutrients and for accurate functionality of neuronal networks. Vascularization of the spinal cord is a highly stereotypical process. However, the guidance cues controlling blood vessel patterning in this organ remain largely unknown. Here we describe a new neuro-vascular communication mechanism that controls vessel guidance in the developing spinal cord. We show that motor neuron columns remain avascular during a developmental time window, despite expressing high levels of the pro-angiogenic vascular endothelial growth factor (VEGF). We describe that motor neurons express the VEGF trapping receptor sFlt1 via a Neuropilin-1-dependent mechanism. Using a VEGF gain-of-function approach in mice and a motor neuron-specific sFlt1 loss-of-function approach in chicken, we show that motor neurons control blood vessel patterning by an autocrine mechanism that titrates motor neuron-derived VEGF via their own expression of sFlt1. The guidance cues regulating blood vessel patterning in the central nervous system remain unclear. Here, the authors show in mice and chicken developing spinal cord that motor neurons control blood vessel patterning by an autocrine mechanism titrating VEGF via the expression of its trapping receptor sFlt1.
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Affiliation(s)
- Patricia Himmels
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Isidora Paredes
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Heike Adler
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Andromachi Karakatsani
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Robert Luck
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Hugo H Marti
- Institute of Physiology and Pathophysiology, Heidelberg University, 69120 Heidelberg, Germany
| | - Olga Ermakova
- Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Eugen Rempel
- Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Esther T Stoeckli
- Institute of Molecular Life Sciences, University of Zurich, 8057 Zurich, Switzerland
| | - Carmen Ruiz de Almodóvar
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
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