RhoA distribution in renal caveolar fractions in experimental type 1 diabetes

Caveolae act as signalling platforms serving as concentrating points for numerous signalling molecules, as well as regulating flux through many distinct signalling cascades. RhoA proteins have been identified as potential actors in the pathophysiology of the cardiovascular system. We used sucrose gradient fractionation and immunoblotting to determine caveolin-1 and RhoA presence in the kidney cortex of streptozotocin-induced T1 diabetes rats (4-week duration), and of diabetic rats treated with angiotensin receptor blocker losartan (4 weeks, 20 mg/kg/day) to retard renal hypertension. Positive RhoA/caveolin-1 co-immunoprecipitation result was detected in the caveolar fraction that corresponded to the light-scattering band obtained from diabetic rats, compared to negative co-immunoprecipitation result in the caveolar fraction obtained from control rats. The detection of RhoA protein in the caveolar fractions and the prospective RhoA/caveolin-1 association can be used to examine the role of these signalling reactions in the pathophysiology of microvascular complications in type 1 diabetes.