Resolvin D1-mediated cellular crosstalk protects against MASH.

BACKGROUND & AIMS: Recent studies have highlighted the beneficial effect of resolvin D1 (RvD1), a docosahexaenoic acid-derived specialized pro-resolving mediator, on chronic liver diseases, but the underlying mechanisms are not well understood. Our study aimed to determine the role and mechanism of RvD1-mediated cellular crosstalk in metabolic dysfunction-associated steatohepatitis (MASH). METHODS: RvD1 was administered to mice with experimental MASH, followed by bulk and single cell RNA sequencing (scRNA-seq) analysis. Primary liver cells, including primary hepatocytes, Kupffer cells (KCs), T cells, and hepatic stellate cells (HSCs), were isolated for co-culture experiments to elucidate the effect of RvD1 on cell death, inflammation, and fibrosis. RESULTS: Hepatic tissue levels of RvD1 were decreased in murine (n = 5-6, p <0.01) and human MASH (n = 9-10, p <0.05). Administering RvD1 reduced hepatocellular death, inflammation, and liver fibrosis in MASH (n = 4-5, p <0.05). Mechanistically, RvD1 reduced hepatocyte death by suppressing endoplasmic reticulum (ER) stress. Co-culture experiments with primary liver cells showed that conditioned media from palmitic acid-treated hepatocytes activated KCs, T cells, and HSCs; however, those effects were abolished from RvD1-pretreated hepatocytes. Moreover, RvD1 directly suppressed T cell activation and IFNγ production, leading to reduced Stat1-Cxcl10 signaling in KCs. CONCLUSIONS: RvD1 reduced hepatocyte death and DAMP production by alleviating ER stress-mediated apoptosis, leading to decreased activation of KCs, T cells, and HSCs. This study highlights the novel role of RvD1-mediated cellular crosstalk among different liver cells in MASH. IMPACT AND IMPLICATIONS: MASH is a growing healthcare burden worldwide. However, current treatments for MASH and its sequelae remain limited. Recent studies highlighted the therapeutic benefit of specialized pro-resolving mediators (SPMs), including RvD1, in liver diseases. However, the mechanisms underlying these beneficial effects are not well understood. Based on a series of co-culture primary cell experiments and unbiased transcriptomic analyses, we show that RvD1-mediated cellular crosstalk among hepatocytes and nonparenchymal cells protects against MASH progression. Our study provides a new mechanistic insight into the role of RvD1 in MASH and highlights its therapeutic potential to treat this condition.