CircGLI3 Inhibits Oxidative Stress by Regulating the miR-339-5p/VEGFA Axis in IPEC-J2 Cells.

Zhi-Xin Li,Wei Chen,Yu Zhang,Yong-Qing Zeng,Li-Xue Wang,Sijie Tan

doi:10.1155/2021/1086206

Zhi-Xin Li, Wei Chen + Show 4 more

Open Access

https://doi.org/10.1155/2021/1086206

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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.

Highlights

Oxidative stress (OS) is usually defined as a state of imbalance between the production of free radicals or reactive oxygen species (ROS) in the body and the body’s antioxidant protection mechanisms [1]
It reported that intestinal paracellular permeability and ROS production would increase under the condition of oxidative stress in the small intestine [5, 6]
The results show that circGLI3 can act as a sponge of miR339-5p to affect the expression of VEGFA and eventually modulate IPEC-J2 cell proliferation and ROS content

Summary

Introduction

Oxidative stress (OS) is usually defined as a state of imbalance between the production of free radicals or reactive oxygen species (ROS) in the body and the body’s antioxidant protection mechanisms [1]. This imbalance leads to damage to important biomolecules and cells, with a potential impact on the whole organism [2]. Numerous studies have shown that OS may be the main factor leading to the occurrence and development of many diseases in piglets [4] It reported that intestinal paracellular permeability and ROS production would increase under the condition of oxidative stress in the small intestine [5, 6]. These evidences showed that small intestine cells might be sensitive to OS

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