Jonathan Qi

Biomarkers to predict risk of liver fibrosis in subjects with nonalcoholic fatty liver disease, a common risk factor for hepatocellular carcinoma, would allow for early preventive interventions. We sought to characterize bile acid profiles associated with liver fibrosis in subjects from the community‐based Cameron County Hispanic Cohort, a population in South Texas with high rates of nonalcoholic fatty liver disease, liver fibrosis and hepatocellular carcinoma. Plasma bile acid levels were measured in 390 subjects. These subjects were screened with liver elastography, detecting significant liver fibrosis in 58 subjects and steatosis in 186 subjects. Unsupervised clustering of the bile acid profiles revealed five clusters that differed by liver fibrosis, liver steatosis, liver injury, age and gender, identifying these parameters as major determinants of circulating bile acid changes. Total bile acid levels were significantly higher in subjects with fibrosis, with chenodeoxycholic acid displaying the greatest increase among individual bile acids. The primary conjugated bile acids, glycocholic and glycochenodeoxycholic acids, displayed the strongest association with fibrosis by logistic regression. High lithocholic acid levels were strongly associated with advanced fibrosis. In contrast, deoxycholic acid and total unconjugated secondary bile acids were positively associated with steatosis, whereas relative glycoursodeoxycholic acid abundance was negatively associated. Milk and yogurt intake notably contributed to fibrosis‐associated bile acid changes. In addition, multiple families within the Firmicutes phylum, Prevotellaceae, and Bacteroides species in stool significantly correlated with fibrosis‐associated and steatosis‐associated bile acid parameters, suggesting that the gut microbiome contributes to bile acid changes in the context of liver disease. Conclusion: Circulating bile acid levels were markedly but differently changed in liver fibrosis and steatosis in a high‐risk Mexican‐American population.

Abstract Liver cancer ranks amongst the deadliest cancers. Nerves have emerged as an understudied regulator of tumor progression. The parasympathetic vagus nerve influences systemic immunity via acetylcholine (ACh). Whether cholinergic neuroimmune interactions influence hepatocellular carcinoma (HCC) remains uncertain. Liver denervation via hepatic vagotomy (HV) significantly reduced liver tumor burden, while pharmacological enhancement of parasympathetic tone promoted tumor growth. Cholinergic disruption in Rag1KO mice revealed that cholinergic regulation requires adaptive immunity. Further scRNA-seq and in vitro studies indicated that vagal ACh dampens CD8+ T cell activity via muscarinic ACh receptor (AChR) CHRM3. Depletion of CD8+ T cells abrogated HV outcomes and selective deletion of Chrm3 on CD8 + T cells inhibited liver tumor growth. Beyond tumor-specific outcomes, vagotomy improved cancer-associated fatigue and anxiety-like behavior. As microbiota transplantation from HCC donors was sufficient to impair behavior, we investigated putative microbiota-neuroimmune crosstalk. Tumor, rather than vagotomy, robustly altered fecal bacterial composition, increasing Desulfovibrionales and Clostridial taxa. Strikingly, in tumor-free mice, vagotomy permitted HCC-associated microbiota to activate hepatic CD8+ T cells. These findings reveal that gut bacteria influence behavior and liver anti-tumor immunity via a dynamic and pharmaceutically targetable, vagus-liver axis.

Objective Liver metastases are often resistant to immune checkpoint inhibitor therapy (ICI) and portend a worse prognosis compared with metastases to other locations. Regulatory T cells (Tregs) are one of several immunosuppressive cells implicated in ICI resistance of liver tumours, but the role played by Tregs residing within the liver surrounding a tumour is unknown. Design Flow cytometry and single-cell RNA sequencing were used to characterise hepatic Tregs before and after ICI therapy. Results We found that the murine liver houses a Treg population that, unlike those found in other organs, is both highly proliferative and apoptotic at baseline. On administration of αPD-1, αPD-L1 or αCTLA4, the liver Treg population doubled regardless of the presence of an intrahepatic tumour. Remarkably, this change was not due to the preferential expansion of the subpopulation of Tregs that express PD-1. Instead, a subpopulation of CD29 + ( Itgb1 , integrin β1) Tregs, that were highly proliferative at baseline, doubled its size in response to αPD-1. Partial and full depletion of Tregs identified CD29 + Tregs as the prominent niche-filling subpopulation in the liver, and CD29 + Tregs demonstrated enhanced suppression in vitro when derived from the liver but not the spleen. We identified IL2 as a critical modulator of both CD29 + and CD29 − hepatic Tregs, but expansion of the liver Treg population with αPD-1 driven by CD29 + Tregs was in part IL2-independent. Conclusion We propose that CD29 + Tregs constitute a unique subpopulation of hepatic Tregs that are primed to respond to ICI agents and mediate resistance.

<h3>Background & Aims</h3> Inbred mouse strains are critical tools for studying immune regulation of metabolic dysfunction-associated steatohepatitis (MASH) and hepatocellular carcinoma (HCC). Here, we profiled mouse strain-associated hepatic immune differences, and performed mice–human cross-species immune comparisons. <h3>Methods</h3> Immune landscapes of C57BL/6, BALB/c, and FVB/N mice were compared under healthy, MASH, or HCC state using high-dimensional spectral flow cytometry (n = 4 per condition). MASH was induced by feeding methionine- and choline-deficient or Western diet + carbon tetrachloride. HCC was caused by hydrodynamic plasmid injection of MYC/sg-p53. Public mouse and human scRNA-seq datasets were used for validation and cross-species comparisons. <h3>Results</h3> In healthy mice, liver CD4⁺ T (24% <i>vs.</i> 14% <i>vs.</i> 34%, <i>p</i> <0.05) and B cells (36.5% <i>vs.</i> 35% <i>vs.</i>18%, <i>p</i> <0.05) varied the most among three strains. C57BL/6 mice showed T_H1 dominance, whereas BALB/c and FVB/N mice had T_H2 dominance (log[T_H1:T_H2] = 0.17, -0.31, -0.17). In MASH mice, expansion of liver myeloid cells and innate lymphocytes were commonly found, but changes of B cells (log(fold-change) = -0.38, -0.28, -0.58, <i>p</i> <0.05) and T subsets (<i>e.g.</i> CD4⁺ T log(fold-change) = -0.21, -0.07, -0.15, <i>p</i> <0.05) varied greatly among strains. MYC/sg-p53 HCC induced a consistent expansion of liver Tregs and CD8⁺ T cells (<i>p</i> <0.05), but differential shifts of liver immune landscape were seen among strains. The flow cytometry data was supported by public scRNA-seq datasets matching C57BL/6 background. Further cross-species comparison in MASH condition confirmed shared changes of adaptive lymphocytes between mice and humans. In two MASH models, BALB/c or C57BL/6 mice were more consistent to recapture loss of CD4⁺ T or B cells, respectively (<i>p</i> <0.05). <h3>Conclusions</h3> Substantial liver immune differences exist among common mouse strains. Mice can recapitulate certain human liver immune changes with strain variations. <h3>Impact and implications</h3> Our immune cell profiling study revealed that the liver immune environment can be quite different among common mouse strains both under healthy and pathologic states, such as steatohepatitis or neoplastic processes. Our results serve as a data resource for studies investigating liver immunology and provide valuable insights for the design of studies on various immune cells in the livers of mice.