circGLI3 Inhibits Oxidative Stress by Regulating the miR-339-5p/VEGFA Axis in IPEC-J2 Cells

Abstract

As a new type of noncoding RNA, circular RNA (circRNA) is stable in cells and not easily degraded. This type of RNA can also competitively bind miRNAs to regulate the expression of their target genes. The role of circRNA in the mechanism of intestinal oxidative stress (OS) in weaned piglets is still unclear. In our research, diquat (DQ) was used to induce OS in small intestinal epithelial cells (IPEC-J2) to construct an OS cell model. Mechanistically, dual luciferase reporter assays, fluorescence in situ hybridization (FISH), and western blotting were performed to confirm that circGLI3 directly sponged miR-339-5p and regulated the expression of VEGFA. Overexpression of circGLI3 promoted IPEC-J2 cell proliferation, increased the proportion of S-phase cells ( P < 0.01 ), and reduced reactive oxygen species (ROS) generation when IPEC-J2 cells were subjected to OS. circGLI3 can increase the activity of glutathione peroxidase (GSH-Px) and the total antioxidant capacity (T-AOC) in IPEC-J2 cells and reduce the malondialdehyde (MDA) content and levels of inflammatory factors. Therefore, overexpression of circGLI3 reduced oxidative damage, whereas miR-339-5p mimic counteracted these effects. We identified a regulatory network composed of circGLI3, miR-339-5p, and VEGFA and verified that circGLI3 regulates VEGFA by directly binding miR-339-5p. The expression of VEGFA affects IPEC-J2 cell proliferation, cell cycle progression, and ROS content and changes the levels of antioxidant enzymes and inflammatory factors. This study reveals the molecular mechanism by which circGLI3 inhibits OS in the intestine of piglets and provides a theoretical basis for further research on the effect of OS on intestinal function.

Simultaneous Extraction and Analysis of Seven Major Saikosaponins from Bupleuri Radix and the Exploration of Antioxidant Activity and Its Mechanism

“…The more significant the chance of there being an antioxidant effect through the target, the greater the chance of there being an antioxidant effect. As shown in Figure 7, saikosaponins interact with 28 proteins with the highest degree of CASP3, VEGFA, and STAT3 among the core targets of antioxidant action, where the expression of the target VEGFA affects IPEC-J2 cell proliferation, cell cycle progression, and ROS content and alters the levels of antioxidant enzymes and inflammatory factors [39]. CASP3 is involved in the apoptosis process, where hypoxia and nutrient deficiency can significantly increase apoptosis [40].…”

“…cell cycle progression, and ROS content and alters the levels of antioxidant enzymes and inflammatory factors [39]. CASP3 is involved in the apoptosis process, where hypoxia and nutrient deficiency can significantly increase apoptosis [40].…”