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Vascular endothelial growth factor (VEGF) induces phosphorylation of VEGF receptor-2 (VEGFR-2) and activates the downstream signaling pathway resulting in endothelial cell migration, proliferation, and survival. Cigarette smoking is associated with abnormal vascular and endothelial function, leading to airspace enlargement. Herein, we investigated the mechanism of cigarette smoke (CS) -induced endothelial dysfunction by studying the VEGF-VEGFR-2 signaling in mouse lung and human endothelial cells. CS exposure caused oxidative stress, as shown by increased levels of 4-hydroxy-2-n0nenal-adducts in mouse lung and reactive oxygen species generation in human lung microvascular endothelial cells (HMVEC-Ls). Inhibition of VEGFR-2 by a specific kinase inhibitor (NVP-AAD777) enhanced the CS-induced oxidative stress, causing augmented inflammatory cell influx and proinflammatory mediators release in mouse lung. The levels of endothelial nitric oxide synthase (eNOS) and phosphorylated (p) -eNOS in the lungs of mice exposed to CS and/or treated with VEGFR-2 inhibitor were decreased. CS down-regulated VEGFR-2 expression, eNOS levels, and VEGF-induced VEGFR-2 phosphorylation in HMVEC-Ls, resulting in impaired VEGF-induced endothelial cell migration and angiogenesis. Overall, these data show that inhibition of VEGFR-2 augmented CS-induced oxidative stress and inflarmnatory responses leading to endothelial dysfunction. This explains the mechanism of endothelial dysfunction in smokers and has implications in understanding the pathogenesis of pulmonary and cardiovascular diseases.--Edirisinghe, I., Yang, S.-E., Yao, H., Rajendrasozhan, S., Caito, S., Adenuga, D., Wong, C., Rahman, A., Phipps, R. P., Jin, Z.-G., Rahman, I. VEGFR-2 inhibition augments cigarette smoke-induced oxidative stress and inflammatory responses leading to endothelial dysfunction. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factor (VEGF) is essential for many angiogenic processes. Histone deacetylases (HDACs) have emerged as key transcriptional regulators. Here we showed that VEGF induced Protein kinase D (PKD)-dependent HDAC5 phosphorylation and nuclear export in endothelial cells. VEGF rapidly, stimulated HDAC5 phosphorylation (p-HDAC5) at Ser259/498 residues in a time- and dose-dependent manner in bovine aortic endothelial cells and human umbilical vein endothelial cells. VEGF-induced p-HDAC5 was mediated via VEGF receptor 2, phospholipase Cγ (PLCγ), protein kinase C (PKC) and PKD pathway. Specifically, PLCγ and PKCs inhibitors diminished p-HDAC5. Inhibiting PKD by siRNA and adenovirus encoding kinase-negative mutant blocked p-HDACS. Furthermore, VEGF stimulated nuclear export of HDAC5 in a phosphorylation-dependent manner, which leads to myocyte enhance factors-2 (MEF2) transcriptional activation. Active PKD stimulated HDAC5 nuclear export and MEF2 activation. In contrast, inhibiting PKD prevented VEGF-mediated HDAC5 nuclear export and MEF2 activation. Moreover, adenovirus encoding HDAC5 S258/498A mutant abolished VEGF-mediated HDAC5 nuclear export and MEF2 activation. Our findings reveal a novel role of PKD and HDAC5 in VEGF regulation of gene transcription and suggest that PKD and HDAC5 may emerge as potential therapeutic targets for pathological angiogenesis. [ABSTRACT FROM AUTHOR]