Parallel expression level of dystrophin and contractile performances of rat aortic smooth muscle.

We have recently shown that the expression of dystrophin was in line with the conservation of contractility in primary and subcultured vascular smooth muscle cells (VSMC). In this report, we provide experimental evidence that shows the existence of a gradient in dystrophin expression from the aortic arch to the region just above the diaphragm, in line with a parallel gradient of contractility. On the contrary, there were no differences in caldesmon and smooth muscle myosin expression, as previously shown for vimentin and alpha-smooth muscle actin [Osborn, M., Caselitz, J., and Weber, K. (1981) Differentiation 20, 196-202]. Overall, this is the first demonstration, in a normal adult smooth muscle, of a differential expression of dystrophin, in line with its contractile performances. In addition, these results suggest that the experimental modulation of dystrophin expression in cultured VSMC in line with their contractility was the manifestation in vitro of an actual physiological property of those cells in vivo.