Abstract
Background and PurposeRegulation of the homeostasis of vascular endothelium is critical for the processes of vascular remodeling and angiogenesis under physiological and pathological conditions. Urotensin II (U-II), a potent vasoactive peptide, participates in vascular and myocardial remodeling after injury. We investigated the protective effect of U-II on doxorubicin (DOX)-induced apoptosis in cultured human umbilical vein endothelial cells (HUVECs) and the potential mechanisms involved in this process.Experimental ApproachCultured HUVECs were treated with vehicle, DOX (1 µM), U-II, or U-II plus DOX. Apoptosis was evaluated by DNA strand break level with TdT-mediated dUTP nick-end labeling (TUNEL) staining. Western blot analysis was employed to determine the related protein expression and flow cytometry assay was used to determine the TUNEL positive cells.Key ResultsU-II reduced the quantity of cleaved caspase-3 and cytosol cytochrome c and increased Bcl-2 expression, which results in protecting HUVECs from DOX-induced apoptosis. U-II induced Activating transcription factor 3 (ATF3) at both mRNA and protein levels in U-II-treated cells. Knockdown of ATF3 with ATF3 siRNA significantly reduced ATF3 protein levels and U-II protective effect under DOX-treated condition. U-II downregulated p53 expression in DOX-induced HUVECs apoptosis, and it rapidly activated extracellular signal-regulated protein kinase (ERK) and Akt. The DOX induced change of p53 was not affected by U-II antagonist (urantide) under ATF-3 knockdown. The inhibitory effect of U-II on DOX-increased apoptosis was attenuated by inhibitors of ERK (U0126) and PI3K/Akt (LY294002).Conclusion and ImplicationsOur observations provide evidence that U-II protects HUVECs from DOX-induced apoptosis. ERK-Akt phosphorylation, ATF3 activation, and p53 downregulation may play a signal-transduction role in this process.
Highlights
Vascular endothelial cell injury is the critical event in the pathogenesis of cardiovascular diseases [1]
Effects of Urotensin II (U-II) on DOX-induced human umbilical vein endothelial cells (HUVECs) cytotoxicity It has found that low concentrations of DOX, such as 1 mM, induced cell apoptosis in HUVECs [17]
Many vacuoles were formed in the HUVECs by DOX treatment despite the existing U-II (Fig. 1C, left)
Summary
Vascular endothelial cell injury is the critical event in the pathogenesis of cardiovascular diseases [1]. Anti-apoptotic agents may be potential candidates that affect vascular remodeling, which is known to be a key mechanism in the progression of atherosclerosis and other cardiovascular diseases. U-II and GPR14 are highly expressed in endothelial and smooth muscle cells involved in vascular remodeling [5]. They have been associated with several cardiovascular pathologies including pulmonary vascular and atherosclerosis remodeling [5,6]. We investigated the protective effect of U-II on doxorubicin (DOX)-induced apoptosis in cultured human umbilical vein endothelial cells (HUVECs) and the potential mechanisms involved in this process. Western blot analysis was employed to determine the related protein expression and flow cytometry assay was used to determine the TUNEL positive cells
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