Dataset Information

UBA1/GARS-dependent pathways drive sensory-motor connectivity defects in spinal muscular atrophy.

ABSTRACT: Deafferentation of motor neurons as a result of defective sensory-motor connectivity is a critical early event in the pathogenesis of spinal muscular atrophy, but the underlying molecular pathways remain unknown. We show that restoration of ubiquitin-like modifier-activating enzyme 1 (UBA1) was sufficient to correct sensory-motor connectivity in the spinal cord of mice with spinal muscular atrophy. Aminoacyl-tRNA synthetases, including GARS, were identified as downstream targets of UBA1. Regulation of GARS by UBA1 occurred via a non-canonical pathway independent of ubiquitylation. Dysregulation of UBA1/GARS pathways in spinal muscular atrophy mice disrupted sensory neuron fate, phenocopying GARS-dependent defects associated with Charcot-Marie-Tooth disease. Sensory neuron fate was corrected following restoration of UBA1 expression and UBA1/GARS pathways in spinal muscular atrophy mice. We conclude that defective sensory motor connectivity in spinal muscular atrophy results from perturbations in a UBA1/GARS pathway that modulates sensory neuron fate, thereby highlighting significant molecular and phenotypic overlap between spinal muscular atrophy and Charcot-Marie-Tooth disease.

SUBMITTER: Shorrock HK

PROVIDER: S-EPMC6158753 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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UBA1/GARS-dependent pathways drive sensory-motor connectivity defects in spinal muscular atrophy.

Shorrock Hannah K HK van der Hoorn Dinja D Boyd Penelope J PJ Llavero Hurtado Maica M Lamont Douglas J DJ Wirth Brunhilde B Sleigh James N JN Schiavo Giampietro G Wishart Thomas M TM Groen Ewout J N EJN Gillingwater Thomas H TH

Brain : a journal of neurology 20181001 10

Deafferentation of motor neurons as a result of defective sensory-motor connectivity is a critical early event in the pathogenesis of spinal muscular atrophy, but the underlying molecular pathways remain unknown. We show that restoration of ubiquitin-like modifier-activating enzyme 1 (UBA1) was sufficient to correct sensory-motor connectivity in the spinal cord of mice with spinal muscular atrophy. Aminoacyl-tRNA synthetases, including GARS, were identified as downstream targets of UBA1. Regulat ...[more]

PMID: 30239612

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Project description:BackgroundMouse models of mild spinal muscular atrophy (SMA) have been extremely challenging to generate. This paucity of model systems has limited our understanding of pathophysiological events in milder forms of the disease and of the effect of SMN depletion during aging.MethodsA mild mouse model of SMA, termed Smn2B/-;SMN2+/-, was generated by crossing Smn-/-;SMN2 and Smn2B/2B mice. This new model was characterized using behavioral testing, histology, western blot, muscle-nerve electrophysiology as well as ultrasonography to study classical SMA features and extra-neuronal involvement.FindingsSmn2B/-;SMN2+/- mice have normal survival, mild but sustained motor weakness, denervation and neuronal/neuromuscular junction (NMJ) transmission defects, and neurogenic muscle atrophy that are more prominent in male mice. Increased centrally located nuclei, intrinsic contractile and relaxation muscle defects were also identified in both female and male mice, with some male predominance. There was an absence of extra-neuronal pathology.InterpretationThe Smn2B/-;SMN2+/- mouse provides a model of mild SMA, displaying some hallmark features including reduced weight, sustained motor weakness, electrophysiological transmission deficit, NMJ defects, and muscle atrophy. Early and prominent increase central nucleation and intrinsic electrophysiological deficits demonstrate the potential role played by muscle in SMA disease. The use of this model will allow for the understanding of the most susceptible pathogenic molecular changes in motor neurons and muscles, investigation of the effects of SMN depletion in aging, sex differences and most importantly will provide guidance for the currently aging SMA patients treated with the recently approved genetic therapies.FundingThis work was supported by Cure SMA/Families of SMA Canada (grant numbers KOT-1819 and KOT-2021); Muscular Dystrophy Association (USA) (grant number 575466); and Canadian Institutes of Health Research (CIHR) (grant number PJT-156379).

Dataset Information

UBA1/GARS-dependent pathways drive sensory-motor connectivity defects in spinal muscular atrophy.

Publications

UBA1/GARS-dependent pathways drive sensory-motor connectivity defects in spinal muscular atrophy.

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