Targeting BRD4 mitigates hepatocellular lipotoxicity by suppressing the NLRP3 inflammasome activation and GSDMD-mediated hepatocyte pyroptosis.

Nod-like receptor family pyrin-containing protein 3 (NLRP3) inflammasome plays a pathologic role in metabolic dysfunction-associated steatohepatitis (MASH), but the molecular mechanism regulating the NLRP3 inflammasome activation in hepatocellular lipotoxicity remains largely unknown. Bromodomain-containing protein 4 (BRD4) has emerged as a key epigenetic reader of acetylated lysine residues in enhancer regions that control the transcription of key genes. The aim of this study is to investigate if and how BRD4 regulated the NLRP3 inflammasome activation and pyroptosis in MASH. Using the AML12 and primary mouse hepatocytes stimulated by palmitic acid (PA) as an in vitro model of hepatocellular lipotoxicity, we found that targeting BRD4 by genetic knockdown or a selective BRD4 inhibitor MS417 protected against hepatosteatosis; and this protective effect was attributed to inhibiting the activation of NLRP3 inflammasome and reducing the expression of Caspase-1, gasdermin D (GSDMD), interleukin (IL)-1ß and IL-6. Moreover, BRD4 inhibition limited the voltage-dependent anion channel-1 (VDAC1) expression and oligomerization in PA-treated AML12 hepatocytes, thereby suppressing the NLRP3 inflammasome activation. Additionally, the expression of BRD4 enhanced in MASH livers of humans. Mechanistically, BRD4 was upregulated during hepatocellular lipotoxicity that in turn modulated the active epigenetic mark H3K27ac at the promoter regions of the Vdac and Gsdmd genes, thereby enhancing the expression of VDAC and GSDMD. Altogether, our data provide novel insights into epigenetic mechanisms underlying BRD4 activating the NLRP3 inflammasome and promoting GSDMD-mediated pyroptosis in hepatocellular lipotoxicity. Thus, BRD4 might serve as a novel therapeutic target for the treatment of MASH.

Clinical characteristics in patients with SARS-CoV-2/HBV co-infection.

COVID-19 has become a global pandemic and garnered international attention. Although the clinical features of COVID-19-related liver injury have been investigated, there have been no reports and studies on the clinical characteristics of COVID-19 patients co-infected with hepatitis B virus (HBV). This study aimed to evaluate whether SARS-CoV-2/HBV co-infection could influence liver function and the disease outcome. All 326 confirmed COVID-19 cases in Shanghai Public Health Clinical Center (The COVID-19 designated hospital in Shanghai, China) from 20 January 2020 to 24 February 2020 were enrolled and followed up until February 29 in this study. The clinical, laboratory data and the length of stay were collected and analysed retrospectively. 20 patients with HBV co-infection (6.1%) and 306 patients (93.9%) without HBV infection showed no differences in the level of liver function parameters. However, compared with HBsAg- patients [145.4 mg/L (103.9-179.2)], HBsAg + patients had a lower level of prealbumin [(102.3 mg/L (76.22-160.2), P = .0367]. There were also no significant differences for the discharge rate and the length of stay between two groups. Taken together, we found no evidence that SARS-CoV-2/HBV co-infection could aggravate liver injury or extend duration of hospitalization.

Entecavir add-on Peg-interferon therapy plays a positive role in reversing hepatic fibrosis in treatment-naïve chronic hepatitis B patients: a prospective and randomized controlled trial.

BACKGROUND: The efficacy of entecavir (ETV) add-on peg-interferon therapy compared with ETV monotherapy in treatment-naïve hepatitis B virus (HBV) patients remains controversial. We investigated whether adding peg-interferon to ongoing ETV treatment leads to a better curative effect or not. METHODS: All patients have been recruited between August 2013 and January 2015 from the Shanghai Public Health Clinical Center and Zhongshan Hospital (China). Eligible HBV patients (n = 144) were randomly divided (1:1) to receive either ETV monotherapy (n = 70) or peg-interferon add-on therapy from week 26 to 52 (n = 74). Patients were followed-up for at least 2 years. Indexes including hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) seroconversion rate, sustained virologic response, transient elastography value, and histological scores were evaluated every 3 months until the end of the study. The rate of patients with HBsAg loss was defined as the primary endpoint criteria. RESULTS: At week 26, no patient achieved HBsAg seroconversion in either group. At week 52, one patient in the monotherapy group was HBsAg-negative but there was none in the combination therapy group. The monotherapy group showed significantly better liver function recovery results than the combination therapy group. At week 78, one patient in the combination group had HBsAg seroconverted. At week 104, only three patients in the combination therapy group were HBsAg-negative compared with one patient in monotherapy. The mean alanine aminotransferase and aspartate aminotransferase levels and transient elastography values decreased significantly compared with baseline. Both groups showed a favorable decrease in alpha-fetoprotein (monotherapy: 4.5 [2.8, 7.1] vs. 2.2 [1.8, 3.1] ng/mL, P < 0.001; combination therapy: 5.7 [3.0, 18.8] vs. 3.2 [2.0, 4.3] ng/mL, P < 0.001) and an improved result of liver biopsy examination scores. The combination group showed a better improvement in histology compared with the monotherapy group (mean transient elastography value 6.6 [4.9, 9.8] vs. 7.8 [5.4, 11.1] kPa, P = 0.028). But there was no significant difference in HBsAg conversion rate (1.8% [1/56] vs. 4.1% [3/73], P = 0.809) and HBeAg conversion rate (12.5% [7/56] vs. 11.0% [8/73], P = 0.787), as well as HBV-DNA, sustained virologic response (93.2% vs. 98.5%, P = 0.150) between the two groups. CONCLUSIONS: Both therapies supported liver function recovery and histology improvement. Combination therapy did not show better anti-viral efficacy in HBsAg or HBeAg seroconversion compared with monotherapy. However, combination therapy played a more positive role in reversing hepatic fibrosis compared with monotherapy. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02849132; https://clinicaltrials.gov/ct2/show/NCT02849132.