Abstract 11683: Class IIb Histone Deacetylase 6 Regulates Endothelial Cell Migration and Angiogenesis by Deacetylation of Cortactin
Histone deacetylases (HDACs) deacetylate histones and non-histone proteins, thereby affecting protein activity and gene expression. Previous studies identified HDAC5 and HDAC7 as regulators of angiogenesis. The cytoplasmic class IIb HDAC6 is the only HDAC that possesses two functional deacetylase domains, and is known to interact with the cytoskeleton, to be involved in cell migration and in cancer development. The regulation and function of the cytoplasmic class IIb HDAC6 in endothelial cells is largely unexplored. Silencing of HDAC6 in endothelial cells decreases sprouting (36±6%, p<0.05) and migration (30±2%, p<0.05) in vitro. To confirm the role of HDAC6 in mammalian vessel formation, we performed a spheroid-based matrigel plug assay in mice. Knockdown of HDAC6 in the injected cells does not affect vessel density, but decreases the size (63±3%, p<0.01) and perfusion of vessels (p<0.01). Furthermore, HDAC6 regulates embryonic vessel formation in zebrafish and HDAC6-deficient mice showed a reduced formation of perfused vessels in matrigel plugs (48±10%, p<0.05) and a reduced capillary density in the thigh leg (62±10%) and lower leg (79±1%, p<0.05) after hind limb ischemia. Consistently, overexpression of wild-type HDAC6 increases sprouting from spheroids (160±6%, p<0.05). HDAC6 function requires catalytic activity but is independent of ubiquitin binding and deacetylation of α-tubulin. Instead, we found that HDAC6 co-localizes and interacts with the actin remodeling protein cortactin in endothelial cells. Previously, it was shown that HDAC6 deacetylates cortactin, which facilitates its binding to actin, thereby promoting cell motility. Indeed, silencing of HDAC6 increases cortactin acetylation whereas overexpression of HDAC6 decreases acetylation in endothelial cells. Cortactin is essential for zebrafish embryonic vessel formation and regulates in vitro endothelial cell migration and sprouting depending on its acetylation state. Importantly, HDAC6-dependent endothelial cell migration and sprouting is mediated by direct deacetylation of cortactin. In summary, we show that HDAC6 is necessary for angiogenesis involving the interaction and deacetylation of cortactin that regulates endothelial cell migration and sprouting.
- © 2011 by American Heart Association, Inc.