Dataset Information

Circ-CBFB upregulates p66Shc to perturb mitochondrial dynamics in APAP-induced liver injury.

ABSTRACT: p66Shc, a master regulator of mitochondrial reactive oxygen species (mtROS), is a crucial mediator of hepatocyte oxidative stress. However, its functional contribution to acetaminophen (APAP)-induced liver injury and the mechanism by which it is modulated remain unknown. Here, we aimed to assess the effect of p66Shc on APAP-induced liver injury and to evaluate if circular RNA (circRNA) functions as a competitive endogenous RNA (ceRNA) to mediate p66Shc in APAP-induced liver injury. p66Shc-, miR-185-5p-, and circ-CBFB-silenced mice were injected with APAP. AML12 cells were transfected with p66Shc, miR-185-5p, and circ-CBFB silencing or overexpression plasmids or siRNAs prior to APAP stimulation. p66Shc was upregulated in liver tissues in response to APAP, and p66Shc silencing in vivo protected mice from APAP-induced mitochondrial dynamics perturbation and liver injury. p66Shc knockdown in vitro attenuated mitochondrial dynamics and APAP-induced hepatocyte injury. Mechanically, p66Shc perturbs mitochondrial dynamics partially by inhibiting OMA1 ubiquitination. miR-185-5p, which directly suppressed p66Shc translation, was identified by microarray and bioinformatics analyses, and its overexpression attenuated mitochondrial dynamics and hepatocyte injury in vitro. Furthermore, luciferase, pull-down and RNA immunoprecipitation assays demonstrated that circ-CBFB acts as a miRNA sponge of miR-185-5p to mediate p66Shc in APAP-induced liver injury. circ-CBFB knockdown also alleviated APAP-induced mitochondrial dynamics perturbation and hepatocyte injury. More importantly, we found that the protective effects of circ-CBFB knockdown on p66Shc, mitochondrial dynamics and liver injury were abolished by miR-185-5p inhibition both in vivo and in vitro. In conclusion, p66Shc is a key regulator of APAP-induced liver injury that acts by triggering mitochondrial dynamics perturbation. circ-CBFB functions as a ceRNA to regulate p66Shc during APAP-induced liver injury, which may provide a potential therapeutic target.

SUBMITTER: Wang Z

PROVIDER: S-EPMC7648761 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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circ-CBFB upregulates p66Shc to perturb mitochondrial dynamics in APAP-induced liver injury.

Wang Zhecheng Z Zhao Yan Y Sun Ruimin R Sun Yu Y Liu Deshun D Lin Musen M Chen Zhao Z Zhou Junjun J Lv Li L Tian Xiaofeng X Yao Jihong J

Cell death & disease 20201106 11

p66Shc, a master regulator of mitochondrial reactive oxygen species (mtROS), is a crucial mediator of hepatocyte oxidative stress. However, its functional contribution to acetaminophen (APAP)-induced liver injury and the mechanism by which it is modulated remain unknown. Here, we aimed to assess the effect of p66Shc on APAP-induced liver injury and to evaluate if circular RNA (circRNA) functions as a competitive endogenous RNA (ceRNA) to mediate p66Shc in APAP-induced liver injury. p66Shc-, miR- ...[more]

PMID: 33159035

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Project description:As the current clinical treatment of acetaminophen (APAP)‑induced liver injury (AILI) has its limitations, new and effective treatment methods are required. Fingolimod (FTY720) is an immunosuppressive drug developed in recent years that has been shown to have a protective effect against ischemia/reperfusion liver injury. However, the role of FTY720 in AILI remains unclear. The aim of the present study was to determine whether FTY720 has a protective effect on AILI. AILI was induced using intraperitoneal injection of 300 mg/kg APAP in male C57BL/6J mice. Following APAP challenge, the mice were administered 5 mg/kg FTY720 for 30 min. Protein expression levels were measured using western blot analysis. Cell viability was examined using Cell Counting Kit‑8 assays. mRNA levels were measured using reverse transcription‑quantitative PCR. Inflammation levels were evaluated using immunohistochemistry. Cell death and reactive oxygen species levels were examined using immunofluorescence. Furthermore, laser scanning intravital microscopy was used to directly observe immune cell recruitment. APAP treatment increased the serum levels of alanine transaminase and aspartate transaminase at the 6‑ and 12‑h time‑points, suggesting liver tissue damage. However, FTY720 attenuated the liver injury induced by APAP by reducing the recruitment of immune cells and the release of pro‑inflammatory cytokines and chemokines. FTY720 activated JAK2/STAT3 signaling and regulated the expression of BAX, BCL‑2 and p65 to inhibit apoptosis and inflammation. In addition, compared with APAP treatment, the viability of primary hepatocytes treated with APAP and FTY720 was increased. Inhibition of JAK2/STAT3 signaling attenuated the protective, antioxidant effects of FTY720. In conclusion, FTY720 reduced liver injury by regulating the JAK2/STAT3 signaling pathway. This compound was capable of inhibiting oxidative stress to reduce hepatocyte death and the infiltration of neutrophils in the liver.

Project description: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 (O2 -) 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.

Dataset Information

Circ-CBFB upregulates p66Shc to perturb mitochondrial dynamics in APAP-induced liver injury.

Publications

circ-CBFB upregulates p66Shc to perturb mitochondrial dynamics in APAP-induced liver injury.

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