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

摘要

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 a-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 a-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 a-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.