The Mislocalization of TDP-43 to Mitochondria Impairs Myotube Maturation.

Aggregation of TDP-43 in neuronal cells is a defining neuropathological hallmark of amyotrophic lateral sclerosis (ALS). Emerging evidence suggests that TDP-43 pathology also occurs in skeletal muscle fibers, but its functional significance in myocytes remains poorly understood. In this study, we utilized the C2C12 myoblast cell to investigate the subcellular localization of TDP-43 during myogenic differentiation. Our findings demonstrate that TDP-43 progressively translocates to mitochondria in parallel with myotube maturation. Notably, increased mitochondrial localization of TDP-43 was also observed in skeletal muscle tissues from patients with ALS, corroborating the clinical relevance of this phenomenon. Functional assays revealed that inhibition of TDP-43 mitochondrial translocation significantly enhances myotube maturation. Collectively, these results support a pathophysiological role for aberrant mitochondrial mislocalization of TDP-43 in regulating myogenic differentiation and contributing to muscle degeneration in TDP-43 proteinopathies.