Stretch-dependent smooth muscledifferentiation in theportal vein - role of actin polymerization, calcium signaling and microRNAs.

The mechanical forces acting onsmooth muscle cells in the vascular wall are known to regulate processes such as vascular remodeling and contractile differentiation. However, investigations to elucidate the underlying mechanisms of mechanotransduction in smooth muscle have been hampered by technical limitations associated with mechanical studies on pressurized small arteries, due primarily to the small amount of available tissue. The murine portal vein is a relatively large vessel showing myogenic tone that in many respects recapitulates the properties of small resistance vessels. Studies on stretched portal veins to elucidate mechanisms of mechanotransduction in the vascular wall have shown that stretch-sensitive regulation of contractile differentiation is mediated via Rho-activation and actin polymerization, while stretch-induced growth is regulated by the MAP-kinase pathway. In this review, we have summarized findings on mechanotransduction in the portal vein with focus on stretch-induced contractile differentiation and the role of calcium, actin polymerization and microRNAs in this response. This article is protected by copyright. All rights reserved.