Laminin α5_CD239_Spectrin is a candidate association that compensates the linkage between the basement membrane and cytoskeleton in skeletal muscle fibers

The linkage between the basement membrane (BM) and cytoskeleton is crucial for muscle fiber stability and signal transduction. Mutations in the linkage molecules can cause various types of muscular dystrophies. The different severities and times of onset suggest that compensatory linkages occur at the sarcolemma. Cluster of differentiation 239 (CD239) binds to the α5 subunit of laminin-511 extracellularly and is connected to spectrin intracellularly, resulting in a linkage between the BM and cytoskeleton. In this study, we explored the linkage of laminin α5_CD239_spectrin in skeletal muscles. Although laminin α5, CD239, and spectrin were present in embryonic skeletal muscles, they disappeared in adult skeletal muscle tissues, except for the soleus and diaphragm. Laminin α5_CD239_spectrin was localized in the skeletal muscle tissues of Duchenne muscular dystrophy and congenital muscular dystrophy mouse models. The experimental regeneration of skeletal muscle increased the CD239-mediated linkage, indicating that it responds to regeneration, but not to genetic influence. Furthermore, in silico analysis showed that laminin α5_CD239_spectrin was upregulated by steroid therapy for muscular dystrophy. Therefore, CD239-mediated linkage may serve as a therapeutic target to prevent the progression of muscular dystrophy.