Temporal regulation of TAK1 to counteract muscular dystrophy
Muscular dystrophy is a group of genetic neuromuscular disorders that involves severe muscle wasting. Transforming growth factor {beta}-activated kinase 1 (TAK1) is an important signaling protein that regulates cell survival, growth, and inflammation. TAK1 has been recently found to promote myofiber growth in skeletal muscle of adult mice. However, the role of TAK1 in muscle disorders remains poorly understood. In the present study, we have investigated how TAK1 affects progression of dystrophic phenotype in the mdx mouse model of Duchnne muscular dystrophy (DMD). TAK1 is highly activated during peak necrotic phase in mdx mice. Targeted inducible inactivation of TAK1 inhibits muscle injury, necroptosis, and accumulation of macrophages in dystrophic muscle of mdx mice. Additionally, targeted inactivation of TAK1 leads to the activation of autophagy and Notch and Wnt signaling in the dystrophic muscle. However, inactivation of TAK1 significantly reduces myofiber size and muscle contractile function in both young and adult mdx mice. Forced activation of TAK1 in skeletal muscle after peak necrotic phase induces myofiber growth and improves muscle histopathology in mdx mice. Our results suggest that targeted activation of TAK1 can ameliorate disease progression and improve muscle growth in DMD. One Sentence SummaryOur results demonstrate that duly regulation of TAK1 activity ameliorates dystrophic phenotype in a mouse model of Duchnne Muscular Dystrophy.