Background: ENO3 expression is upregulated in Non-alcoholic fatty liver disease (NAFLD) patient tissues, demonstrated that ENO3 might play crucial roles in NAFLD. However, the mechanism of ENO3 in NAFLD remains unclear. Therefore, this study aimed to investigate the regulatory mechanism of ENO3 in the progression of non-alcoholic steatohepatitis (NASH) in vivo and vitro NASH model. Methods: In vivo and vitro NASH model were established by methionine-choline deficient (MCD)-diet feeding and high free fatty acid (HFFA) induction in L02 cells. Loss and gain function of ENO3 and GPX4 was performed to study the mechanism in NASH. Western blot was used to detect the expression of ENO3 and GPX4. Hematoxylin and eosin (H&E), picrosirius Red and Oil Red O staining was used to evaluate histopathology of liver in NASH model. Ferroptosis indicators were measured by assay kits according to the manufacturer’s instructions. Results: NASH mouse model was successfully established induced by MCD diet with steatosis, inflammatory infiltration, ballooning and fibrosis observed in the liver tissue. The expression of ENO3 and GPX4 was significantly elevated while ferroptosis was inhibited in NASH mice and cell model. Upregulation of both ENO3 and GPX4 could promote the lipid accumulation in L02 cells. In addition, overexpressed ENO3 attenuated the status of ferroptosis. Conclusions: In the present study, we demonstrate that ENO3 promoted the progression of NASH by negatively regulating ferroptosis via elevating GPX4 expression and lipid accumulation. These findings provided solid foundation for the mechanism of ferroptosis on the progression of NASH regulated by ENO3, suggesting that ENO3 may be a potential therapeutic target for NASH.

Background: Circular RNA (circRNA) is emerging as an important player in human diseases, especially cancer. In our previous study, we identified a series of deregulated circRNAs in hepatocellular carcinoma (HCC) by performing circRNA microarray expression profile. Here, we aimed to explore the role of circ-LRIG3 (hsa_circ_0027345) in HCC.Methods: qRT-PCR and western blot were used to asses gene and protein expression, respectively. CCK-8, EdU and Transwell assays were used to detect cell proliferation, migration and invasion. GSEA software was applied to analyze the pathway related to circ-LRIG3. Co-IP, RIP and ChIP assays were used to identify the positive feedback axis of circ-LRIG3/EZH2/STAT3. Animal study was carried to test the role of circ-LRIG3 in vivo.Results: Circ-LRIG3 was notably upregulated in HCC and promoted HCC cell proliferation, migration, invasion and reduced apoptosis. Circ-LRIG3 formed a ternary complex with EZH2 and STAT3, facilitating EZH2-induced STAT3 methylation and subsequent phosphorylation, resulting in the activation of STAT3 signaling. In turn, activated STAT3 could directly bind to circ-LRIG3 promoter to increase circ-LRIG3 transcription activity, thus forming a positive feedback loop. The animal models showed that exogenous expression of circ-LRIG3 enhanced tumorigenicity and metastasis in vivo, whereas these effects were blocked after treatment with C188–9, a specific STAT3 small-molecule inhibitor. Clinically, high circ-LRIG3 was closely linked with aggressive clinicopathological features and was identified as an independent risk prognostic factor of overall survival. Importantly, plasma circ-LRIG3 was found to be a highly sensitive and specific non-invasive diagnostic indicator for HCC.Conclusions: Our study reveals the carcinogenic role of circ-LRIG3 in HCC, which may provide a new therapeutic target for HCC patients.

Objective: Premature senescence is related to progerin and involves in endothelial dysfunction and liver diseases. Activating sirtuin 1 (SIRT1) ameliorates liver fibrosis. However, the mechanisms of premature senescence in defenestration of hepatic sinusoidal endothelial cells (HSECs) and how SIRT1 affects HSECs fenestrae remain elusive.Methods: We employed the CCl₄‐induced liver fibrogenesis rat models and cultured primary HSECs in vitro, administered with the SIRT1‐adenovirus vector, the activator of SIRT1 and knockdown NOX2. We measured the activity of senescence‐associated β‐galactosidase (SA‐β‐gal) in HSECs. Meanwhile, the protein expression of SIRT1, NOX2, progerin, Lamin A/C, Ac p53 K381 and total p53 was detected by Western blot, co‐immunoprecipitation and immunofluorescence.Results: In vivo, premature senescence was triggered by oxidative stress during CCl₄‐induced HSECs defenestration and liver fibrogenesis, whereas overexpressing SIRT1 with adenovirus vector lessened premature senescence to relieve CCl₄‐induced HSECs defenestration and liver fibrosis. In vitro, HSECs fenestrae disappeared, with emerging progerin‐associated premature senescence; these effects were aggravated by H₂O₂. Nevertheless, knockdown of NOX2, activation of SIRT1 with resveratrol and SIRT1‐adenovirus vector inhibited progerin‐associated premature senescence to maintain fenestrae through deacetylating p53. Furthermore, more Ac p53 K381 and progerin co‐localized with the abnormal accumulation of actin filament (F‐actin) in the nuclear envelope of H₂O₂‐treated HSECs; in contrast, these effects were rescued by overexpressing SIRT1.Conclusion: SIRT1‐mediated deacetylation maintains HSECs fenestrae and attenuates liver fibrogenesis through inhibiting oxidative stress‐induced premature senescence.