Nuclear receptor subfamily 4 group a member 1 eases angiotensin II-arose oxidative stress in vascular smooth muscle cell by boosting nucleotide-binding oligomerization domain-like receptor family caspase recruitment domain containing 3 transcription.

Objective: Hypertension significantly contributes to morbidity and mortality. Nuclear receptor subfamily 4 group a member 1 (Nur77) participates in regulating oxidative stress, but the mechanism in hypertension remains unclear. This study aimed to explore the function of Nur77 in oxidative stress induced by Angiotensin II (Ang II) in vascular smooth muscle cells (VSMCs) in hypertension.

Material and methods: First, models of VSMC with Nur77, nucleotide-binding oligomerization domain-like receptor family caspase recruitment domain containing 3 (NLRC3) and tumor necrosis factor receptor-associated factor 6 (TRAF6) knockdown or overexpression were constructed using Short Hairpin RNA (Nur77) or pcDNA3.1 vector, respectively. Next, the putative-binding motifs between Nur77 and NLRC3 promoters were detected by dual luciferase assay. We conducted reverse transcription quantitative polymerase chain reaction (qPCR) and Western blot (WB) analysis to detect Nur77, NLRC3, and TRAF6 levels in VSMCs. Then, cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, wound-healing assay, enzyme-linked immunosorbent assay, and 2',7'-dichlorofluorescin diacetate were employed to examine the impact of the knockdown or overexpression of Nur77, NLRC3, and TRAF6 on VSMCs treated with Ang II. The assays measured cell viability and proliferation, cell migration, malondialdehyde levels, and reactive oxygen species levels.

Results: The overexpression of Nur77 repressed cell growth (P < 0.001), migration (P < 0.01), and oxidative stress (P < 0.01) induced by Ang II in VSMCs. Nur77 transcriptionally promoted the expression of NLRC3 (P < 0.001), and the upregulation of NLRC3 suppressed cell proliferation (P < 0.05) and oxidative stress (P < 0.001) mediated by Ang II. Furthermore, NLRC3 negatively regulated the TRAF6/nuclear factor-kappa B (NF-κB) axis activated by Ang II, which resulted in the repression of hyperproliferation of VSMCs (P < 0.01) and oxidative stress (P < 0.001).

Conclusion: Nur77 suppressed growth and oxidative stress induced by Ang II in VSMCs by promoting NLRC3 transcription, which, further, repressed the TRAF6/NF-κB axis. This understanding provides novel insights into the pathogenesis of hypertension.