Talin, Vinculin and Nestin Expression in Orofacial Muscles of Dystrophin Deficient mdx Mice

Abstract

The activity of cytoskeletal proteins like talin, vinculin and nestin increases in muscle that regenerates. Little is known about their role or at least their expression in the process of regeneration in masticatory muscles of mdx mice, a model of Duchenne muscular dystrophy. To determine a potential role of cytoskeletal proteins in the regeneration process of mdx masticatory muscles, we examined the expression of talin 1, talin 2, vinculin and nestin in 100-day-old control and mdx mice using quantitative RT-PCR, Western blot analyses and histochemistry. The protein expression of talin 1, talin 2, nestin and vinculin in mdx muscles remained unchanged as compared with normal mice. However, in mdx masseter it was found a relative increase of nestin compared to controls. The protein expression of talin 1 and vinculin tended to be increased in mdx tongue and talin 2 to diminish in mdx masseter and temporal muscle. In mdx mice, we found significantly lower percentage of transcripts coding for nestin, talin 1, talin 2 and vinculin in masseter (p < 0.05) and temporal muscle (p < 0.001). In contrast, the mRNA expression of nestin was found to be increased in mdx tongue. Activated satellite cells, myoblasts and immature regenerated muscle fibres in mdx masseter and temporal revealed positive staining for nestin. The findings of the presented work suggest dystrophin-lack-associated changes in the expression of cytoskeletal proteins in mdx masticatory muscles could be compensatory for dystrophin absence. The expression of nestin may serve as an indicator for the regeneration in the orofacial muscles.

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“…The cytoskeletal protein, talin, acts as an essential link between integrins and the actin cytoskeleton in several functionally distinct adhesion complexes, including focal adhesions, costameres and intercalated disks [ 27 ]. Vertebrates contain two talin proteins (TLN1 and TLN2), and the activity of these proteins increases during muscle regeneration [ 27 , 28 ]. TLN1 is essential for maintaining the connection between integrins and myofilaments at myotendinous junctions, while TLN2 may compensate for some functions of TLN1 [ 29 ].…”

“…It is induced during striated muscle differentiation and is targeted to stable adhesion complexes in mature muscle [ 27 ]. Tln2 diminished in masseter and temporal muscle of mdx mice, a model of Duchenne muscular dystrophy [ 28 ]. In cells lacking talin 2, there is no activation of β1 integrin, and loss of the extracellular matrix-integrin-cytoskeleton linkage and sustained cell spreading and adhesion [ 30 ].…”