Vsig4 + Resident Single-Kupffer Cells Improve Hepatic Inflammation and Fibrosis in NASH

The role of macrophages in the pathogenesis of nonalcoholic steatohepatitis (NASH) is complex and unclear. Here, single-cell RNA sequencing was performed on nonparenchymal cells isolated from NASH and control mice. Two main single macrophage subsets were identified that exhibited a significant change in cell percentage when NASH occurred: resident Kupffer cells (KCs; Cluster 2) and lipid-associated macrophages (LAMs; Cluster 13). Nearly 93% of single-LAMs in Cluster 13 specifically expressed Cx3cr1, and an increase in Cx3crl + single-LAMs was speculated to play a proinflammatory role in NASH. Nearly 82% of resident single KCs in Cluster 2 specifically expressed Cd163, and an inhibited subgroup of Cd163 + resident single-KCs was suggested to have a protective effect in NASH. Similar to Cd163, Vsig4 was both enriched in and specific to Cluster 2. The percentage of Vsig4 + -KCs was significantly decreased in NASH in vivo and in vitro . Hepatocytes and hepatic stellate cells produced less lipid droplet accumulation, proinflammatory protein (TNF-α) and profibrotic protein (α-SMA) in response to coculture with Vsig4 + -KCs than in those cocultured with lipotoxic KCs. Therefore, a subgroup of Vsig4 + resident single-KCs was shown to improve hepatic inflammation and fibrosis in NASH.