Hu antigen R is required for NOX-1 but not NOX-4 regulation by inflammatory stimuli in vascular smooth muscle cells

Abstract

Objective NOX-1 and NOX-4 are key enzymes responsible for reactive oxygen species (ROS) generation in vascular smooth muscle cells (VSMC). The RNA-binding protein HuR is implicated in post-transcriptional regulation of gene expression; however, its role regulating NOX is unknown. We investigated transcriptional and post-transcriptional mechanisms underlying angiotensinII (AngII) and interleukin-1β (IL-1β) regulation of NOX-1 and NOX-4 in VSMC and their implications in cell migration. Methods Rat and human VSMC were stimulated with AngII (0.1 μM) and/or IL-1β (10 ng/mL). NOX-1 and NOX-4 mRNA and protein levels, NOX-1 and NOX-4 promoter and 3′UTR activities, NADPH oxidase activity, ROS production and cell migration were studied. Results IL-1β increased NOX-1 expression, NADPH oxidase activity and ROS production and decreased NOX-4 expression and H2O2 production in VSMC. AngII potentiated the IL-1β-mediated induction of NOX-1 expression, NADPH oxidase activity, ROS production and cell migration. However, AngII did not influence IL-1β-induced NOX-4 down-regulation. AngII+IL-1β interfered with the decay of NOX-1 mRNA and promoted HuR binding to NOX-1 mRNA. Moreover, HuR blockade reduced NOX-1 mRNA stability and AngII+IL-1β-induced NOX-1 mRNA levels. IL-1β decreased NOX-4 expression through a transcriptional mechanism that involved response elements situated in the proximal promoter. AngII and/or IL-1β-induced cell migration were prevented by NOX-1 and HuR blockade and were augmented by NOX-4 overexpression. Conclusion In VSMC HuR-mediated mRNA stabilization is partially responsible for AngII+IL-1β-dependent NOX-1 expression whereas transcriptional mechanisms are involved in decreased NOX-4 expression induced by IL-1β. NOX4 and HuR regulation of NOX-1 contributes to VSMC migration, important in vascular inflammation and remodeling.

Modulation of the mRNA-binding protein HuR as a novel reversal mechanism of epirubicin-triggered multidrug resistance in colorectal cancer cells

“…It has also been reported that ROS generation triggered cytoplasmic translocation of HuR, leading to enhancement in activity of TGFβ pathway (ROS-HuR-TGFβ pathway) [ 28 ]. Moreover, HuR was implicated in posttranscriptional regulation of NADPH oxidase-1 (NOX-1), one crucial enzyme for ROS production [ 29 ]. We therefore suspected that modulating HuR might affect the generation of ROS induced by Epi.…”

Klf5 down-regulation induces vascular senescence through eIF5a depletion and mitochondrial fission

“…It has been known that NAPDH oxidase (NOX)1 and NOX4 are key enzymes responsible for ROS generation in VSMCs [36]. To understand the source of ROS and to determine the association of Ang II signaling, Klf5, and eIF5α with NOX expression, mouse VSMCs were transfected with expression vectors for Klf5 and eIF5α or small interfering RNA (siRNA) against Klf5 and eIF5α, respectively, and then treated with Ang II for 0, 1, 3, and 5 days, and the expression of NOX1 and NOX4 was detected by RT-qPCR.…”

A Potential Link Between Oxidative Stress and Endothelial-to-Mesenchymal Transition in Systemic Sclerosis

“…For instance, in rat aortic smooth muscle cells, production of ROS by IL-1β is mediated by NOX4 ( 43 ). Although IL1-β induces its expression ( 44 ), NOX1 does not appear to be involved in IL1-β-induced ROS production ( 43 ). In addition, TGF-β has been shown to induce NOX4 expression as well as ROS production in human arterial smooth muscle cells ( 45 ).…”