In-silico structural analysis of E509K mutation in LARGE and T192M mutation in Alpha Dystroglycan in the inhibition of glycosylation of Alpha Dystroglycan by LARGE

Gene-editing, immunological and iPSCs based therapeutics for muscular dystrophy

Muscular dystrophy is a well-known genetically heterogeneous group of rare muscle disorders. This progressive disease causes the breakdown of skeletal muscles over time and leads to grave weakness. This breakdown is caused by a diverse pattern of mutations in dystrophin and dystrophin associated protein complex. These mutations lead to the production of altered proteins in response to which, the body stimulates production of various cytokines and immune cells, particularly reactive oxygen species and NFκB. Immune cells display/exhibit a dual role by inducing muscle damage and muscle repair. Various anti-oxidants, anti-inflammatory and glucocorticoid drugs serve as potent therapeutics for muscular dystrophy. Along with the above mentioned therapeutics, induced pluripotent stem cells also serve as a novel approach paving a way for personalized treatment. These pluripotent stem cells allow regeneration of large numbers of regenerative myogenic progenitors that can be administered in muscular dystrophy patients which assist in the recovery of lost muscle fibers. In this review, we have summarized gene-editing, immunological and induced pluripotent stem cell based therapeutics for muscular dystrophy treatment.

Identification and Modeling of a GT-A Fold in the α-Dystroglycan Glycosylating Enzyme LARGE1

The acetylglucosaminyltransferase-like protein LARGE1 is an enzyme that is responsible for the final steps of the post-translational modifications of dystroglycan (DG), a membrane receptor that links the cytoskeleton with the extracellular matrix in the skeletal muscle and in a variety of other tissues. LARGE1 acts by adding the repeating disaccharide unit [-3Xyl-α1,3GlcAβ1-] to the extracellular portion of the DG complex (α-DG); defects in the LARGE1 gene result in an aberrant glycosylation of α-DG and consequent impairment of its binding to laminin, eventually affecting the connection between the cell and the extracellular environment. In the skeletal muscle, this leads to degeneration of the muscular tissue and muscular dystrophy. So far, a few missense mutations have been identified within the LARGE1 protein and linked to congenital muscular dystrophy, and because no structural information is available on this enzyme, our understanding of the molecular mechanisms underlying these pathologies is still very limited. Here, we generated a 3D model structure of the two catalytic domains of LARGE1, combining different molecular modeling approaches. Furthermore, by using molecular dynamics simulations, we analyzed the effect on the structure and stability of the first catalytic domain of the pathological missense mutation S331F that gives rise to a severe form of muscle–eye–brain disease.