A study of myoblast integrin, adhesion and differentiation /

Treatment of chick myoblasts with the glucosidase inhibitors bromoconduritol (BCD) or N-methyl-1-deoxynojirimycin (MDJN), but not the mannosidase I inhibitor 1-deoxymannojirimycin (ManDJN), decreased the rate of cell-adhesion to fibronectin and laminin and increased the rate of adhesion to collagen. The adhesion of chick myoblasts is predominantly mediated by integrin(s), as judged by inhibition of adhesion by an anti-integrin antibody (JG22). The effects of BCD, MDJN and ManDJN on myoblast integrin detectable at the myoblast cell surface with JG22 antibody correlated well with their effects on adhesion to fibronectin and laminin, and paralleled the previously reported effects of these agents on myogenesis. Interaction of integrin with the extracellular matrix appears critical for terminal differentiation. Mn$sp{2+}$ ions increased myoblast adhesion to ECM proteins, and antagonized the effect of BCD and MDJN on myoblast differentiation.Finally BCD and MDJN were found to act at an early stage in myoblast differentiation, down regulating the expression of both myogenin and muscle $alpha$-actin mRNA in L$sb6$ myoblasts