Myoblast transplantations lead to the expression of the laminin α2 chain in normal and dystrophic (dy/dy) mouse muscles

Laminin-2 is part of the basement membrane of the skeletal muscle fibers. The laminin α2 chain is absent or drastically reduced in a subgroup of congenital muscular dystrophy patients, and in the severely affected dystrophic dy/dy mouse. We previously reported that heterogenous primary mouse muscle cell cultures conferred laminin α2 chain expression in dy/dy mice muscles upon cell transplantation. In the present study we investigated whether pure myoblast cell lines were able to confer laminin α2 chain expression in vivo. We observed that: (1) xenotransplantation of non-immortalized human myoblast in SCID mouse muscles allows human laminin α2 chain expression; (2) allotransplantation of the permanent G8 mouse myoblast cell line in dy/dy muscles allows the expression of the murine laminin α2 chain; and (3) allotransplantation of the D7 dystrophic dy/dy cell line allows the formation of new and hybrid muscle fibers in dy/dy muscle in the absence of laminin α2 chain expression. We conclude that normal myoblasts are able to restore the expression of an extracellular skeletal muscle protein and that the absence of laminin-2 does not prevent transplanted muscle cells from participating in the formation of myofibers. Myoblasts are, therefore, attractive tools for further exploration of gene complementation strategies in the animal models of congenital muscular dystrophy.