Islr regulates satellite cells asymmetric division through Sparc/p-ERK1/2 signaling pathway

Satellite cells are adult muscle stem cells responsible for muscle regeneration after acute or chronic injuries. The balance between stem cell self-renewal and differentiation impacts the kinetics and efficiency of skeletal muscle regeneration. This study elucidated the function of Islr in satellite cell asymmetric division. Satellite cell specific deletion of Islr compromises muscle regeneration in adult mice by impairing the satellite cell pool. Islr is pivotal for satellite cell proliferation and its deletion promotes asymmetric cell fate segregation of satellite cells. A mechanistic search revealed that Islr interacts and stabilizes the Sparc protein, which activates p-ERK1/2 signaling required for asymmetric division. In combination, the findings have identified Islr as a key regulator of satellite cell asymmetric division through the Sparc/p-ERK1/2 signaling pathway, which provides a new insight into satellite cell biology and open avenues for the treatment of myopathy. Satellite cells were isolated by Fluorescence-activated cell sorting (FACS) according to the presence or absence of Islr and analyzed using RNAseq.