Duchenne muscular dystrophy (DMD), is a genetic disorder, affecting 1 in 3500 males. DMD is caused by defects in the protein dystrophin, which leads to a fragile muscle membrane that tears easily. Normal muscle processes become aberrant and gradual degeneration of muscle throughout the body occurs. They become wheelchair bound by the age of 10 and suffer cardio-respiratory failure which leads to their death by the age of 30.
An understanding of why normal muscle repair processes are defective in DMD may pave the way for future therapies. One signalling pathway that is dysfunctional in DMD is the Wingless (Wnt) pathway1. In kidney repair, the cilium, a hair like organelle on cells is involved in regulating this pathway2.
Interestingly in the mouse model of DMD (mdx mouse), the diaphragm is indicative of the normal muscle degeneration that occurs in the human patients but the gastrocnemius repairs.
The current study aims to assess whether the primary cilium is involved in regulating the Wnt signaling pathway and hence facilitating normal repair in the gastrocnemius of mdx mice.
Immunofluorescence was used to visualize the structure of the cilium (alpha-acetylated tubulin) on muscle cells in mdx mouse compared to uninjured control mice. Histology was used to provide a framework to correlate changes in cilium structure with injury and subsequent repair. Increases in cilium length were found in the gastrocnemius of mdx mice compared to control mice. Previous studies in kidney repair have correlated increases in cilium length with increased cilium function and subsequent repair processes.
Augmenting cilia length and hence function in DMD patients could promote muscle repair. Future studies will aim to assess the potential role of cilium lengthening in Wnt signalling of muscle repair.