circ-PRKCB acts as a ceRNA to regulate p66Shc-mediated oxidative stress in intestinal ischemia/reperfusion

Abstract

Background: Oxidative stress has emerged as an essential factor in the pathogenesis of intestinal ischemia/reperfusion (I/R) injury. The adaptor protein p66Shc is a key regulator of reactive oxygen species (ROS) generation and a mediator of I/R damage in the intestine, but the upstream mechanisms that directly regulate p66Shc expression during intestinal I/R remain largely unknown. Recent studies have suggested that noncoding RNAs, such as circular RNAs (circRNAs), are important players in physiological and pathological processes based on their versatile regulatory roles in gene expression. The aim of this study was to elucidate the contribution of p66Shc to oxidative damage in intestinal I/R and to investigate the regulation of p66Shc by circRNA sponges. Methods: Intestinal I/R was induced in mice via superior mesenteric artery (SMA) occlusion. A miR-339-5p agomir or circ-protein kinase C beta (PRKCB) siRNA was injected intravenously before I/R challenge. In addition, Caco-2 cells were subjected to hypoxia/reoxygenation (H/R) in vitro to simulate an in vivo I/R model. Results: In vitro , p66Shc deficiency significantly reduced H/R-induced ROS overproduction by attenuating mitochondrial superoxide anion (O 2 - ) levels, suppressing NADPH oxidase activity and enhancing antioxidant enzyme expression. Moreover, miR-339-5p was identified to directly regulate p66Shc expression in the intestine. Furthermore, we found that a circRNA transcribed from the PRKCB gene, named circ-PRKCB, acted as an endogenous miR-339-5p sponge to regulate p66Shc expression. circ-PRKCB silencing or miR-339-5p overexpression significantly downregulated p66Shc expression and attenuated oxidative stress levels and I/R injury in vivo and in vitro . Notably, the increased circ-PRKCB levels and decreased miR-339-5p levels associated with murine intestinal I/R were consistent with those in patients with intestinal infarction. Conclusions: Our findings reveal a crucial role for the circ-PRKCB/miR-339-5p/p66Shc signaling pathway in regulating oxidative stress in the I/R intestine. This pathway may be a potential therapeutic target for intestinal I/R injury.

The gut microbiota metabolite capsiate promotes Gpx4 expression by activating TRPV1 to inhibit intestinal ischemia reperfusion-induced ferroptosis

“…Establish a mouse small intestinal organoids H/R model to observe ferroptosis of organoids, and then Fer were used to explore the role of ferroptosis played in organoids H/R injury. Total GSH ( Figure 2a ) and the total GSH/GSSG ratio ( Figure 2b ) were lower, while MDA ( Figure 2c ) and Fe 2+ ( Figure 2d ) levels were higher in the H/R group than in the NC group, and there was no significant difference in total GSH, total GSH/GSSG ratio, MDA and Fe 2 + levels between NC group and NC + Fer group. Meanwhile, the mRNA and protein levels of Gpx4 and Fth1 were downregulated, while the mRNA and protein levels of Cox-2 were upregulated by organoid H/R ( Figure 2(e-h) , Fig.…”

“… 1 However, several fatal diseases, such as traumatic shock, severe infection, and severe burns, can cause intestinal ischemia/reperfusion (I/R) injury. 2 Compared with the local injury that occurs during intestinal ischemia, the intestinal flora displacement and massive release of endotoxins and inflammatory factors that occur during blood reperfusion often leading to intestinal and intestinal distal organ (lung, liver, kidney, heart, brain, etc.) failure and even death.…”

Emerging Clues of Regulatory Roles of Circular RNAs through Modulating Oxidative Stress: Focus on Neurological and Vascular Diseases

“…CircPRKCB can regulate p66Shc expression and hypoxia/reoxygenation- (H/R-) induced oxidative stress acting as an endogenous miR-339-5p sponge. The silencing of circPRKCB significantly inhibited the increased expression of intracellular ROS levels, mitochondrial O 2 levels, and NOX2 and the decreased expression of H/R-induced manganese SOD and catalase [ 105 ].…”

Circular RNAs in the Regulation of Oxidative Stress

“…The key role of the circPRKCB/miR-339-5p/p66Shc signaling pathway in regulating I/R intestinal oxidative stress has been demonstrated. This pathway may serve as a potential therapeutic target for intestinal I/R injury ( Feng et al, 2020 ).…”