Potential effects of different cell death inhibitors in protecting against ischemia-reperfusion injury in steatotic liver.

Liver ischemia-reperfusion injury (IRI) remains a common issue and with the increasing incidence of Nonalcoholic fatty liver disease (NAFLD), which are more sensitive to IRI, it is crucial to explore the possible strategy to alleviate the steatotic liver IRI. Several modes of cell death are involved in hepatocytes and immune cells during hepatic IRI, and the effects of different cell death inhibitors including apoptosis, necroptosis, pyroptosis, and ferroptosis in steatotic liver IRI have not been investigated. We established 70% IRI model on steatotic liver in mice. Apoptosis, necroptosis, pyroptosis and ferroptosis inhibitors were used to evaluate their effects on liver injury, inflammatory response, and immune cell infiltration. Immunofluorescence and immunohistochemical results demonstrated that there were apoptosis, necroptosis, pyroptosis, and ferroptosis in the progression of IRI in steatotic liver. All four types of cell death inhibitors showed protective effects, but ferroptosis inhibitor Fer-1 and pyroptosis inhibitor VX765 exerted better protective effects compared the apoptosis inhibitor Z-VAD and necroptosis inhibitor Nec-1. Further, we found that pyroptosis occurred mainly in macrophages and ferroptosis occured primarily in hepatocytes during steatotic liver IRI. Ferroptosis in heaptocytes and pyroptosis in macrophages are two major cell death types involved in steatotic liver IRI and inhibiting these cell death exerted good protective effects.

Quantitative proteomics of HFD-induced fatty liver uncovers novel transcription factors of lipid metabolism.

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease, which progression is tightly regulated by transcription factors (TFs), nuclear receptors, and cellular enzymes. In this study, a label-free quantitative proteomic approach was used to determine the effect of the high-fat diet on the proteomics profile of liver tissue and to identify novel NAFLD related TFs. Mice were fed with HFD for 16 weeks to establish a NAFLD mouse model. Mice fed with normal chow diet were taken as controls. Liver samples were collected from each group for proteomics analysis. A total of 2298 proteins were quantified, among which 106 proteins were downregulated, while 256 proteins were upregulated in HFD-fed mice compared with the controls with fold change more than 1.5 and p value less than 0.05. Bioinformatic analysis revealed that metabolic-related functions and pathways were most significantly enriched. A subgroup of 11 TFs were observed to share interactions with metabolic-related enzymes and kinases by protein-protein interaction analysis. Among them, 7 TFs were selected for verification, and 3 TFs were finally validated, including Rbbp4, Tcea1, and ILF2. Downregulating each of the 3 TFs could significantly promote lipid accumulation in AML12 hepatocytes, by regulating the expression of fatty acid synthesis- or ß-oxidation-related genes. In contrast, overexpression of Tcea1, Rbbp4, and ILF2, respectively, could ameliorate hepatocyte steatosis. These findings propose novel lipid metabolism related TFs, which might have potential roles in preventing NAFLD.