Serum Exosomal Long Noncoding RNA Growth Arrest-Specific 5 Predicts 3-Month Mortality in Acute-on-Chronic Hepatitis B Liver Failure

BACKGROUND: Acute-on-chronic hepatitis B liver failure (ACHBLF) is a clinical syndrome with an extremely high mortality. In this study, we aim to evaluate the potential role of serum exosomal long noncoding RNA (lncRNA) growth arrest-specific 5 (GAS5) in ACHBLF and its predictive value for 3-month mortality. METHODS: From December 2017 to June 2022, we enrolled 110 patients with ACHBLF and 42 healthy controls (HCs). Exosomes were isolated from the serum of the participants. Serum exosomal lncRNA GAS5 was detected using quantitative real-time polymerase chain reaction (qRT-PCR). The functional role of lncRNA GAS5 on hepatocyte phenotypes was investigated through loss-of-function and gain-of-function assays. Exosomal labeling and cell uptake assay were used to determine the exosomes-mediated transmission of lncRNA GAS5 in hepatocytes in vitro. RESULTS: The serum exosomal lncRNA GAS5 was identified to be an independent predictor for 3-month mortality of ACHBLF. It yielded an area under the receiver operating characteristic curve (AUC) of 0.88, which was significantly higher than MELD score (AUC 0.73; P < 0.01). Further study found that lncRNA GAS5 could inhibit hepatocytes proliferation and increase hepatocytes apoptosis. Exosomes-mediated lncRNA GAS5 transfer promoted hepatocytes injury. The knocked down of lncRNA GAS5 weakened H(2)O(2)-induced hepatocytes injury. CONCLUSION: We revealed that serum exosomal lncRNA GAS5 might promote hepatocytes injury and showed high predictive value for 3-month mortality in ACHBLF.