Abstract
Nuclear receptor subfamily 4 group A member 3 (NR4A3) protects the vascular endothelial cell (VEC) against hypoxia stress, whose expression is primarily reported to be governed at a transcriptional level. However, the regulation of NR4A3 in the protein level is largely unknown. Here, we report that NR4A3 protein abundance is decreased immensely in VEC injury induced by reoxygenation after oxygen-glucose deprivation (OGD-R), which is significantly blocked by the administration of the antioxidative steroid TRIOL. Moreover, the notable improvement of NR4A3 and the alleviation of pulmonary endothelial barrier hyperpermeability induced by acute hypobaric hypoxia in cynomolgus monkeys are also observed after TRIOL administration. The overproduction of reactive oxygen species (ROS) decreases NR4A3 protein abundance in VEC under OGD-R condition, which is reversed by TRIOL and N-acetylcysteine (NAC). TRIOL dose-dependently increases the NR4A3 protein level by inhibiting ubiquitination and ubiquitin proteasome system- (UPS-) mediated degradation rather than promoting its transcription. Using yeast two-hybrid screening, we further identify the interaction between NR4A3 and SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1), and the DNA-binding domain of NR4A3 is required for this interaction. Knockdown of SMARCB1 reduces ubiquitination and degradation of NR4A3, suggesting the proubiquitylation effect of this interaction which is enhanced by ROS in VEC injury induced by OGD-R. In summary, our study here for the first time reveals a posttranslational regulation in SMARCB1-mediated NR4A3 protein degradation which is driven by ROS, providing further understanding of the impaired regulation of NR4A3-mediated prosurvival pathways under pathological condition in VEC.
Highlights
The vascular endothelial cell (VEC) is the core composition of the endothelial barrier, and its injury induced by various pathological stimuli such as ischemia-reperfusion or hypoxia leads to endothelial barrier hyperpermeability [1,2,3]
Given the importance of NR4A3 on regulating cell survival, we firstly explored the NR4A3 protein expression in an injury model of VEC induced by oxygen-glucose deprivation (OGD-R)
These results indicated that the upregulation of NR4A3 by TRIOL contributed to the protection on VEC in vitro, which were further confirmed in vivo using an acute lung injury (ALI) model of nonhuman primate cynomolgus monkeys induced by acute hypobaric hypoxia [33]
Summary
The vascular endothelial cell (VEC) is the core composition of the endothelial barrier, and its injury induced by various pathological stimuli such as ischemia-reperfusion or hypoxia leads to endothelial barrier hyperpermeability [1,2,3]. Oxidative Medicine and Cellular Longevity derived orphan receptor-1 (NOR1), acts as a transcriptional activator and is involved in the regulation of physiological and pathological processes such as metabolism, inflammation, cell proliferation, apoptosis, and differentiation [6]. Previous research has demonstrated that the upregulation of NR4A3 promotes cell survival under different pathological injuries. The enhanced NR4A3 improves VEC survival under hypoxia condition by upregulating cellular inhibitor of apoptosis 2 (cIAP2) against cell apoptosis [8] and protects neurons from oxidative stress and excitotoxicity induced by glutamate [9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
