Metabolically and epigenetically reprogrammed splenic TRNP1hiCD8+ T cells exacerbate liver fibrosis

MASLD, especially its severe form MASH, progresses to liver fibrosis, leading to cirrhosis and liver cancer. The crosstalk between spleen and liver in MASLD/MASH progression remains poorly understood. Here, we find the enlarged spleens in MASLD patients, and the induced TRNP1hiCD8+ T cells in the spleens of MASLD/MASH mouse models and confirmed in MASLD patients, with pro-fibrotic property by secreting INSR-α. Mechanistically, demethylated DNA and H3K27me3, increased H3K27ac, together with bolstered enhancer-promoter contact, synergistically reorganized chromatin topologically associating domains spatially to initiate the expression of transcription factor TRNP1 in splenic CD8+ T cells. TRNP1 then transcriptionally activates the expression of FURIN and CTSD, promoting the maturation and ectodomain shedding of INSR-α thereby facilitating its secretion to activate hepatic stellate cells. In vivo blockade of INSR-α using neutralizing antibodies alleviates MASLD/MASH-induced liver fibrosis. Therefore, this study reveals splenic TRNP1hiCD8+ T cells with pro-fibrotic property and suggests a potential anti-fibrotic strategy.