Conversely, phosphorylation of myosin regulatory light chain (MLC) not only increases actomyosin ATPase activity, but also destabilizes the endothelial cell−cell junctions leading to increased monolayer cell permeability [26], [16], [27].Our results are encouraging and they warrant future research on demonstrating whether ectopic expression of Myl9 in the aged endothelium causes endothelial dysfunction. This evidence concerns the gene MYL2 and endothelial dysfunction.