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.

Mitochondria, oxidative stress and nonalcoholic fatty liver disease: A complex relationship

“…Another example can be the 66 kDa isoform of Shc (p66shc), an adaptor and redox protein that has been already linked to the lipid metabolism regulation by numerous reports 192 . It has been demonstrated that p66Shc participates in various mechanisms of liver injury 193,194 . In livers of NAFLD patients, expression levels of apoptosis regulating proteins p53, p21 and p66Shc were significantly increased 195 .…”

Cancer-Associated Exosomal CBFB Facilitates the Aggressive Phenotype, Evasion of Oxidative Stress, and Preferential Predisposition to Bone Prometastatic Factor of Breast Cancer Progression

“…Previous studies have found that it works by triggering perturbations in mitochondrial dynamics. circ-CBFB acts as a ceRNA to play a regulatory role during cell injury, which may provide a potential therapeutic target [ 39 ].…”

Circular RNA as An Epigenetic Regulator in Chronic Liver Diseases

“…For acetaminophen (APAP)-induced liver injury, p66Shc, a master regulator of mtROS, is upregulated in liver tissues in response to APAP. circ-CBFB acts as the sponge of miR-185-5p, triggering mitochondrial dynamics perturbation via p66Shc [95]. For the hydrogen peroxide (H 2 O 2 )induced injury, circRNA-4099 augments H 2 O 2 -induced damage by inhibiting miR-706 and triggering Keap1/Nrf2 and p38MAPK in the L02 cells [96].…”