Gut microbiota promotes macrophage M1 polarization in hepatic sinusoidal obstruction syndrome via regulating intestinal barrier function mediated by butyrate.

BACKGROUND: The intestinal-liver axis is associated with various liver diseases. Here, we verified the role of the gut microbiota and macrophage activation in the progression of pyrrolizidine alkaloids-induced hepatic sinusoidal obstruction syndrome (PA-HSOS), and explored the possible mechanisms and new treatment options. METHODS: The HSOS murine model was induced by gavage of monocrotaline (MCT). An analysis of 16S ribosomal DNA (16S rDNA) of the feces was conducted to determine the composition of the fecal microbiota. Macrophage clearance, fecal microbiota transplantation (FMT), and butyrate supplementation experiments were used to assess the role of intestinal flora, gut barrier, and macrophage activation and to explore the relationships among these three variables. RESULTS: Activated macrophages and low microflora diversity were observed in HSOS patients and murine models. Depletion of macrophages attenuated inflammatory reactions and apoptosis in the mouse liver. Moreover, compared with control-FMT mice, the exacerbation of severe liver injury was detected in HSOS-FMT mice. Specifically, butyrate fecal concentrations were significantly reduced in HSOS mice, and administration of butyrate could partially alleviated liver damage and improved the intestinal barrier in vitro and in vivo. Furthermore, elevated lipopolysaccharides in the portal vein and high proportions of M1 macrophages in the liver were also detected in HSOS-FMT mice and mice without butyrate treatment, which resulted in severe inflammatory responses and further accelerated HSOS progression. CONCLUSIONS: These results suggested that the gut microbiota exacerbated HSOS progression by regulating macrophage M1 polarization via altered intestinal barrier function mediated by butyrate. Our study has identified new strategies for the clinical treatment of HSOS.

Comparison of metastasis and prognosis between early-onset and late-onset hepatocellular carcinoma: A population-based study.

Background: While hepatocellular carcinoma (HCC) represents a highly heterogeneous disease with variable oncogenesis mechanisms and biological features, little is understood about differences in distant metastasis (DM) and prognosis between early-onset and late-onset HCC. This study defined early-onset disease as cancer diagnosed at age younger than 50 years and aimed to present a comprehensive analysis to characterize these disparities based on age. Methods: Information of HCC patients was retrospectively collected from the SEER database and our hospital. Patient demographics, tumor characteristics, and survival were compared between the two groups. A 1:1 propensity score matching (PSM) was adopted to adjust confounding factors. Logistic and cox analysis were utilized to explore risk factors of DM and prognosis, respectively. Besides, the survival differences were assessed by the Kaplan-Meier curve and log-rank test. Results: In total, 19187 HCC patients obtained from the SEER database and 129 HCC patients obtained from our own center were enrolled. Among 19187 patients with HCC, 3376 were identified in the matched cohort, including 1688 early-onset patients and 1688 late-onset patients. Compared with late-onset HCC, early-onset HCC was more likely to occur in female (25.2% vs. 22.9%, P = 0.030), have large tumors (>10.0 cm, 24.1% vs. 14.6%, P = 0.000), harbor poorly differentiated/undifferentiated cancers (17.0% vs. 14.0%, P = 0.003), present advanced clinical stage (T3+T4, 33.7% vs. 28.5%; N1, 9.2% vs. 6.7%; P = 0.000), and develop DM (13.0% vs. 9.5%, P = 0.000). After adjustment for confounders by PSM, we discovered that early-onset HCC remained an independent risk factor for DM. However, combined with Kaplan-Meier curve and cox analysis, early-onset HCC was an independent favorable predictor of survival. We validated these data on an independent cohort from our hospital. Conclusion: In this population-based study, despite developing DM more frequently, early-onset HCC exhibited a superior prognosis than late-onset HCC. Nevertheless, further research is warranted to understand the underlying aetiologic basis for the disparities.

O-GlcNAcylation promotes the progression of nonalcoholic fatty liver disease by upregulating the expression and function of CD36.

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease (NAFLD) and its progressive variant, nonalcoholic steatohepatitis (NASH), constitute a burgeoning worldwide epidemic with no FDA-approved pharmacotherapies. The multifunctional immunometabolic receptor, fatty acid translocase CD36 (CD36), plays an important role in the progression of hepatic steatosis. O-GlcNAcylation is a crucial posttranslational modification that mediates the distribution and function of CD36, but its involvement in NAFLD remains poorly understood. METHODS: O-GlcNAcylation and CD36 expression were evaluated in human liver tissues obtained from NASH patients and normal control. Mice with hepatocyte-specific CD36 knockout were administered adeno-associated viral vectors expressing wild-type CD36 (WT-CD36) or CD36 O-GlcNAcylation site mutants (S468A&T470A-CD36) and were provided with a high-fat/high-cholesterol (HFHC) diet for 3 months. RT-qPCR analysis, immunoblotting, dual-luciferase reporter assays, chromatin immunoprecipitation, and coimmunoprecipitation were performed to explore the mechanisms by which O-GlcNAcylation regulates CD36 expression. Membrane protein extraction, immunofluorescence analysis, site-directed mutagenesis, and fatty acid uptake assays were conducted to elucidate the impact of O-GlcNAcylation on CD36 function. RESULTS: O-GlcNAcylation and CD36 expression were significantly increased in patients with NASH, mouse models of NASH, and palmitic acid-stimulated hepatocytes. Mechanistically, the increase in O-GlcNAcylation facilitated the transcription of CD36 via the NF-κB signalling pathway and stabilized the CD36 protein by inhibiting its ubiquitination, thereby promoting CD36 expression. On the other hand, O-GlcNAcylation facilitated the membrane localization of CD36, fatty acid uptake, and lipid accumulation. However, site-directed mutagenesis of residues S468 and T470 of CD36 reversed these effects. Furthermore, compared with their WT-CD36 counterparts, HFHC-fed S468A&T470A-CD36 mice exhibited decreases in systemic insulin resistance, steatosis severity, inflammation and fibrosis. Pharmacological inhibition of O-GlcNAcylation and CD36 also mitigated the progression of NASH. CONCLUSIONS: O-GlcNAcylation promotes the progression of NAFLD by upregulating CD36 expression and function. Inhibition of CD36 O-GlcNAcylation protects against NASH, highlighting a potentially effective therapeutic approach for individuals with NASH.

DDX3X interacts with SIRT7 to promote PD-L1 expression to facilitate PDAC progression.

Pancreatic ductal adenocarcinoma (PDAC) is recognized as the most aggressive and fatal malignancy. A previous study reported that PDAC patients who exhibit elevated levels of DDX3X have a poor prognosis and low overall survival rate. However, the underlying molecular mechanism remains unclear. This study aimed to investigate the specific roles of DDX3X in PDAC. Multiple bioinformatics analyses were used to evaluate DDX3X expression and its potential role in PDAC. In vitro and in vivo studies were performed to assess the effects of DDX3X on PDAC cell growth. Furthermore, Western blotting, quantitative PCR, immunohistochemistry, immunofluorescence, mass spectrometry, coimmunoprecipitation and multiplexed immunohistochemical staining were conducted to identify the specific regulatory mechanism in PDAC. The results verified that DDX3X expression is notably upregulated in the tumor tissue vs. normal tissue of PDAC patients. DDX3X knockdown markedly suppressed the proliferation, invasion and migration of PDAC cells in vitro and inhibited tumor growth in vivo. Conversely, overexpression of DDX3X induced the opposite effect. Further studies supported that the DDX3X protein can associate with sirtuin 7 (SIRT7) to stimulate PDAC carcinogenesis and progression. Furthermore, SIRT7 inhibition significantly impeded DDX3X-mediated tumor growth both ex vivo and in vivo. The results also revealed that programmed death ligand 1 (PD-L1) expression is positively correlated with DDX3X expression. These results reveal significant involvement of the DDX3X-SIRT7 axis in the initiation and advancement of PDAC and offer previously undiscovered therapeutic options for PDAC management.