Selective HDAC6 inhibition prevents TNF-α-induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema

Selective HDAC6 inhibition prevents TNF-alpha-induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema. Am J Physiol Lung Cell Mol Physiol 311:L39-L47, 2016. First published May 17, 2016; doi:10.1152/ajplung.00051.2016.-Lung endothelial damage contributes to the pathogenesis of acute lung injury. New strategies against lung endothelial barrier dysfunction may provide therapeutic benefits against lung vascular injury. Cell-cell junctions and microtubule cytoskeleton are basic components in maintaining endothelial barrier integrity. HDAC6, a deacetylase primarily localized in the cytoplasm, has been reported to modulate nonnuclear protein function through deacetylation. Both alpha-tubulin and beta-catenin are substrates for HDAC6. Here, we examined the effects of tubastatin A, a highly selective HDAC6 inhibitor, on TNF-alpha induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema. Selective HDAC6 inhibition by tubastatin A blocked TNF-alpha-induced lung endothelial cell hyperpermeability, which was associated with increased alpha-tubulin acetylation and microtubule stability. Tubastatin A pretreatment inhibited TNF-alpha-induced endothelial cell contraction and actin stress fiber formation with reduced myosin light chain phosphorylation. Selective HDAC6 inhibition by tubastatin A also induced beta-catenin acetylation in human lung endothelial cells, which was associated with increased membrane localization of beta-catenin and stabilization of adherens junctions. HDAC6 knockdown by small interfering RNA also prevented TNF-alpha-induced barrier dysfunction and increased alpha-tubulin and beta-catenin acetylation in endothelial cells. Furthermore, in a mouse model of endotoxemia, tubastatin A was able to prevent endotoxin-induced deacetylation of alpha-tubulin and beta-catenin in lung tissues, which was associated with reduced pulmonary edema. Collectively, our data indicate that selective HDAC6 inhibition by tubastatin A is a potent approach against lung endothelial barrier dysfunction.