Abstract 441: Rgs5 Controls Myogenic Responses of Vascular Smooth Muscle Cells

Contraction of vascular smooth muscle cells (VSMCs) in response to an increase in blood pressure is pivotal for maintaining blood flow and constitutes both consequence and cause of chronic hypertension. While a plethora of contraction-mediating mechanisms has been delineated, not much is known about molecular determinants regulating the responses of VSMCs to an increase in wall stress or biomechanical stretch. In this context, we reported that conditional ablation of Junb - a subunit of the transcription factor AP-1 (activator protein 1) - interferes with the expression of myosin light chain 9 and consequently impaired myogenic responses of arteries. We hypothesized that the arterial circumferential wall stress is increased under these conditions which may influence the VSMC phenotype and vessel wall architecture. In fact, Junb-deficient arteries showed structural remodeling as evidenced by a ~2-3-fold decrease in collagen type I and IV content (n=5, p<0.05). cDNA microarray analyses revealed that express...