Collagen VI myopathies: From the animal model to the clinical trial

Collagen VI is an ECM protein which forms a prominent microfibrillar network in the endomysium of skeletal muscle. Mutations in the genes coding for the three chains of collagen VI cause skeletal muscle diseases; the severe wasting Ullrich congenital muscular dystrophy (UCMD) normally present at birth, and the milder Bethlem myopathy (BM). The pathogenesis of both collagen VI myopathies was unknown until 2003. Our group, utilizing Col6a1 deficient mice, discovered a latent mitochondrial dysfunction that caused increased apoptosis in muscle cells. These effects could be reverted by incubating Col6a1 null muscle fibres with cyclosporin A (CsA), an inhibitor of the mitochondrial permeability pore; more interestingly, the treatment of Col6a1 null mice with CoA rescued the muscle phenotype in vivo. These findings demonstrated an unexpected collagen VI/mitochondrial connection as the basis for the UCMD and BM pathogenesis and suggested a strategy for a possible pharmacological treatment of t...