Oligodendrocyte development and CNS myelination are unaffected in a mouse model of severe spinal muscular atrophy

Abstract

The childhood neurodegenerative disease spinal muscular atrophy (SMA) is caused by loss-of-function mutations or deletions in the Survival Motor Neuron 1 (SMN1) gene resulting in insufficient levels of survival motor neuron (SMN) protein. Classically considered a motor neuron disease, increasing evidence now supports SMA as a multi-system disorder with phenotypes discovered in cortical neuron, astrocyte, and Schwann cell function within the nervous system. In this study, we sought to determine whether Smn was critical for oligodendrocyte (OL) development and central nervous system myelination. A mouse model of severe SMA was used to assess OL growth, migration, differentiation and myelination. All aspects of OL development and function studied were unaffected by Smn depletion. The tremendous impact of Smn depletion on a wide variety of other cell types renders the OL response unique. Further investigation of the OLs derived from SMA models may reveal disease modifiers or a compensatory mechanism allowing these cells to flourish despite the reduced levels of this multifunctional protein.