Mechanisms of bile acid–induced (BA-induced) liver injury in cholestasis are controversial, limiting development of new therapies. We examined how BAs initiate liver injury using isolated liver cells from humans and mice and in-vivo mouse models. At pathophysiologic concentrations, BAs induced proinflammatory cytokine expression in mouse and human hepatocytes, but not in nonparenchymal cells or cholangiocytes. These hepatocyte-specific cytokines stimulated neutrophil chemotaxis. Inflammatory injury was mitigated in Ccl2 ^–/– mice treated with BA or after bile duct ligation, where less hepatic infiltration of neutrophils was detected. Neutrophils in periportal areas of livers from cholestatic patients also correlated with elevations in their serum aminotransferases. This liver-specific inflammatory response required BA entry into hepatocytes via basolateral transporter Ntcp. Pathophysiologic levels of BAs induced markers of ER stress and mitochondrial damage in mouse hepatocytes. Chemokine induction by BAs was reduced in hepatocytes from Tlr9 ^–/– mice, while liver injury was diminished both in conventional and hepatocyte-specific Tlr9 ^–/– mice, confirming a role for Tlr9 in BA-induced liver injury. These findings reveal potentially novel mechanisms whereby BAs elicit a hepatocyte-specific cytokine-induced inflammatory liver injury that involves innate immunity and point to likely novel pathways for treating cholestatic liver disease.

Background. Our study aimed to observe the effect of sodium glucose cotransporter-2 (SGLT2) inhibitor dapagliflozin on diabetic atherosclerosis and investigate the subsequent mechanism.Methods. Aortic atherosclerosis was induced in streptozotocin induced diabetic ApoE^−/−mice by feeding with high-fat diet, and dapagliflozin was administrated intragastrically for 12 weeks as treatment. Effects of dapagliflozin on indices of glucose and fat metabolism, IL-1β, IL-18, NLRP3 protein levels, and the reactive oxygen species (ROS) were measured. The atherosclerosis was evaluated by oil red O and hematoxylin-eosin staining. The effects of dapagliflozin on the IL-1βproduction in culturing primary macrophages of wild type and NLRP3^−/−knockout mice were investigated for mechanism analyses.Results. Dapagliflozin treatment showed favorable effects on glucose and fat metabolism, partially reversed the formation of atherosclerosis, inhibited macrophage infiltration, and enhanced the stability of lesion. Also, reduced production of IL-1β, IL-18, NLRP3 protein, and mitochondrial ROS in the aortic tissues was detected with dapagliflozin treatment. In vitro, NLRP3 inflammasome was activated by hyperglucose and hyperlipid through ROS pathway.Conclusions. Dapagliflozin may be of therapeutic potential for diabetic atherosclerosis induced by high-fat diet, and these benefits may depend on the inhibitory effect on the secretion of IL-1βby macrophages via the ROS-NLRP3-caspase-1 pathway.

N⁶-methyladenosine (m⁶A) RNA modification is a fundamental determinant of mRNA metabolism, but its role in innate immunity-driven non-alcoholic fatty liver disease (NAFLD) and obesity is not known. Here, we show that myeloid lineage-restricted deletion of the m⁶A “writer” protein Methyltransferase Like 3 (METTL3) prevents age-related and diet-induced development of NAFLD and obesity in mice with improved inflammatory and metabolic phenotypes. Mechanistically, loss of METTL3 results in the differential expression of multiple mRNA transcripts marked with m⁶A, with a notable increase of DNA Damage Inducible Transcript 4 (DDIT4) mRNA level. In METTL3-deficient macrophages, there is a significant downregulation of mammalian target of rapamycin (mTOR) and nuclear factor κB (NF-κB) pathway activity in response to cellular stress and cytokine stimulation, which can be restored by knockdown of DDIT4. Taken together, our findings identify the contribution of METTL3-mediated m⁶A modification of Ddit4 mRNA to macrophage metabolic reprogramming in NAFLD and obesity.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading cause of chronic liver disease worldwide. We generated single-cell and spatial transcriptomic and metabolomic maps from 61 human livers, including controls (n = 10), metabolic dysfunction-associated steatotic liver (MASL) (n = 17) and metabolic dysfunction-associated steatohepatitis (MASH) (n = 34). We identified microphthalmia-associated transcription factor (MITF) as a key regulator of the lipid-handling capacity of lipid-associated macrophages (LAMs), and further revealed a hepato-protective role of LAMs mediated through hepatocyte growth factor secretion. Unbiased deconvolution of spatial transcriptomics delineated a fibrosis-associated gene program enriched in advanced MASH, suggesting profibrotic crosstalk between central vein endothelial and hepatic stellate cells within fibrotic regions. Mass spectrometry imaging-based spatial metabolomics demonstrated MASLD-specific accumulation of phospholipids, potentially linked to lipoprotein-associated phospholipase A₂-mediated phospholipid metabolism in LAMs. This spatially resolved multi-omics atlas of human MASLD, which can be queried at the Human Masld Spatial Multiomics Atlas, provides a valuable resource for mechanistic and therapeutic studies.

Nonalcoholic fatty liver disease (NAFLD) has become a common health care burden worldwide. The high heterogeneity of NAFLD remains elusive and impairs outcomes of clinical diagnosis and pharmacotherapy. Several NAFLD classifications have been proposed on the basis of clinical, genetic, alcoholic, or serum metabolic analyses. Yet, accurately predicting the progression of NAFLD to cirrhosis or hepatocellular carcinoma (HCC) in patients remains a challenge. Here, on the basis of a Chinese cohort of patients, we classified NAFLD into three distinct molecular subtypes (NAFLD-mSI, NAFLD-mSII, and NAFLD-mSIII) using integrative multiomics including whole-genome sequencing (WGS), proteomics, phosphoproteomics, lipidomics, and metabolomics across a broad range of liver, blood, and urine specimens. We found that NAFLD-mSI had higher expression of CYP1A2 and CYP3A4, which alleviate hepatic steatosis through mediating free fatty acid/bile acid–mTOR–FXR/PPARα signaling. NAFLD-mSII displayed an elevated risk of liver cirrhosis along with increased hepatic infiltration of M1 and M2 macrophages because of lipid-triggered hepatic CCL2 and CRP production. NAFLD-mSIII exhibited a potential risk for HCC development by increased transcription of CEBPB- and ERCC3-regulated oncogenes because of activation of the EGF-EGFR/CHKA/PI3K-PDK1-AKT cascade. Next, we validated the existence of these three NAFLD molecular subtypes in an external cohort comprising 92 patients with NAFLD across three different Chinese hospitals. These findings may aid in understanding the molecular features underlying NAFLD heterogeneity, thereby facilitating clinical diagnosis and treatment strategies with the aim of preventing the development of liver cirrhosis and HCC.