Dr. Jun Li's Team: ETS2 as a Potential New Target for the Diagnosis and Treatment of HBV-ACLF, Alleviating Liver Failure Progression by Suppressing Macrophage Immune Inflammatory Response

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a complex syndrome characterized by acute liver failure on the basis of chronic hepatitis B, triggered by various factors, with a short-term mortality rate as high as 80%. To overcome the high mortality of HBV-ACLF on an international level, the key lies in breakthroughs in precise diagnosis and theoretical innovations in disease mechanisms, thereby improving early diagnosis, warning, and effective treatment capabilities.  

At the 58th Annual Meeting of the European Association for the Study of the Liver (EASL 2023) and the EASL Congress 2023, Dr. Jun Li from Zhejiang University presented the team's latest findings in an oral presentation: ETS2 can alleviate the progression of acute-on-chronic liver failure by inhibiting the immune inflammatory response of macrophages. It can serve as a molecular marker for the prognosis of liver failure, providing a scientific basis for the development of new diagnostic and therapeutic targets and offering new insights for clinical research on liver failure (Abstract OS-013). Dr. Jun Li's team had several research studies selected for presentation during their participation in EASL.

Research Introduction

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a complex clinical syndrome characterized by acute decompensation of liver function on the basis of chronic hepatitis B, often accompanied by multiple organ failure. Studies have shown that excessive immune inflammatory responses are key factors driving the progression of ACLF. ETS2 is involved in the development of a series of immune-inflammatory-related diseases. However, the role and mechanism of ETS2 in ACLF are not yet clear. This study aims to explore the role and mechanism of the transcription factor ETS2 in the excessive immune inflammatory response in ACLF.

This study, based on the China HBV-ACLF Study Group (COSSH) research cohort, involved stratified random sampling of 50 peripheral blood samples from ACLF patients, 9 samples from liver cirrhosis (LC) patients, 10 samples from chronic hepatitis B (CHB) patients, and 14 samples from healthy individuals as a control group. PBMCs from patients were isolated for mRNA sequencing, and core molecules involved in the progression of HBV-ACLF were selected through inter-group differential comparison. The efficacy of the target gene ETS2 in predicting ACLF patient outcomes was evaluated using the area under the receiver operating characteristic curve (AUROC). Biological functions in which ETS2 is involved during the progression of ACLF were predicted through weighted gene co-expression network analysis and gene enrichment analysis and were subsequently validated in in vivo and in vitro experiments.

Compared to the control group, the expression of ETS2 in PBMCs of ACLF patients and macrophages in liver tissues was significantly increased (P-values <0.01). The expression level of ETS2 was significantly correlated with clinical indicators such as the international normalized ratio (INR) and total bilirubin (TB), and it had good predictive efficacy in distinguishing ACLF patient outcomes at 28/90 days (AUROC: 0.908/0.773). In the co-expression gene module with ETS2, immune response-related functional items were significantly enriched. In the carbon tetrachloride (CCl4) + lipopolysaccharide (LPS) and D-galactosamine (D-Gal) + LPS-induced liver failure models, ETS2-deficient mice exhibited significantly increased liver function indicators (ALT/AST), increased liver cell necrosis, elevated plasma high mobility group box 1 (HMGB1) levels, increased infiltration of inflammatory cells in liver tissues, and increased expression of cytokines IL-1β and IL-6. However, there were no significant changes in extrahepatic organ damage in ETS2-deficient mice in the above models. ETS2 deficiency increased the expression levels of inflammatory factors in macrophages in co-culture systems and enhanced the expression of HMGB1/LPS-induced inflammatory factors in macrophages. ETS2 deficiency promoted the expression of macrophage NF-κB p65 and nuclear translocation of NF-κB p65 induced by LPS. Pre-treatment with the NF-κB inhibitor BAY 11-7082 abolished the promoting effect of ETS2 deficiency on LPS-induced macrophage IL-6 expression.

In conclusion,This study, based on PBMCs transcriptomics, found that ETS2 can accurately predict the 28/90-day mortality of patients and may be involved in regulating the immune response of ACLF patients. At the same time, this study demonstrated that ETS2 can alleviate excessive inflammation and liver tissue damage in CCl4 + LPS and D-Gal + LPS-induced liver failure mice. It can suppress HMGB1/LPS-driven NF-κB-dependent inflammatory factor expression in macrophages, providing a scientific basis for the development of new diagnostic and therapeutic targets for ACLF.

Researcher’s Remarks

Hepatitis B-related acute-on-chronic liver failure (HBV-ACLF) is a complex syndrome characterized by acute organ failure outside the liver on the basis of chronic hepatitis B, with a short-term mortality rate as high as 80%. To tackle the international challenge of high mortality in HBV-ACLF, the key lies in breakthroughs in precise diagnosis and theoretical innovations in disease mechanisms, thereby improving early diagnosis, warning, and effective treatment capabilities. Our research team has previously conducted a nationwide multicenter prospective study on HBV-ACLF, created the Chinese standard COSSH-ACLF for diagnosing HBV-ACLF, and developed a prognostic scoring system. This has increased the accuracy of early diagnosis in critically ill patients by 19% and reduced the mortality rate by 12%. Through multi-omics analysis, we have revealed that the activation of the hepatitis B virus triggers an imbalance in immune metabolism, a core mechanism of HBV-ACLF, and discovered a group of molecular markers with predictive value, including ETS2. This study, through in vivo and in vitro experiments, confirms that ETS2 can serve as a molecular marker for the prognosis of liver failure. It suppresses the inflammatory immune response in macrophages driven by HMGB1/LPS and provides new directions for clinical research on liver failure. However, this study has limitations, as the current mouse model of liver failure cannot fully simulate the pathological and physiological characteristics of HBV-ACLF patients. Currently, our team is working on establishing an improved mouse model for HBV-ACLF to further explore the mechanism of action of ETS2. Additionally, the clinical translational value of drugs targeting ETS2 will need further validation in subsequent studies.