Single-cell transcriptome reveals a novel mechanism of C-Kit+-liver sinusoidal endothelial cells in NASH

Aim: To understand how liver sinusoidal endothelial cells (LSECs) respond to nonalcoholic steatohepatitis (NASH). Methods: We profiled single-LSEC from livers of control and MCD-fed mice. The functions of C-Kit(+)-LSECs were determined using coculture and bone marrow transplantation (BMT) methods. Results: Three special clusters of single-LSEC were differentiated. C-Kit(+)-LSECs of cluster 0, Msr1(+)-LSECs of cluster 1 and Bmp4(+)Selp(+)-VECs of cluster 2 were revealed, and these cells with diverse ectopic expressions of genes participated in regulation of endothelial, fibrosis and lipid metabolism in NASH. The number of C-Kit(+)-primary LSECs isolated from MCD mice was lower than control mice. Immunofluorescence co-staining of CD31 and C-KIT showed C-Kit(+)-LSECs located in hepatic sinusoid were also reduced in NASH patients and MCD mice, compared to AIH patients and control mice respectively. Interestingly, lipotoxic hepatocytes/HSCs cocultured with C-Kit(+)-LSECs or the livers of MCD mice receipting of C-Kit(+)-BMCs (bone marrow cells) showed less steatosis, inflammation and fibrosis, higher expression of prolipolytic FXR and PPAR-alpha, lower expression of TNF-alpha and alpha-SMA. Furthermore, coculturing or BMT of C-Kit(+)-endothelial derived cells could increase the levels of hepatic mitochondrial LC3B, decrease the degree of mitochondrial damage and ROS production through activating Pink1-mediated mitophagy pathway in NASH. Conclusions: Hence, a novel transcriptomic view of LSECs was revealed to have heterogeneity and complexity in NASH. Importantly, a cluster of C-Kit(+)-LSECs was confirmed to recovery Pink1-related mitophagy and NASH progression.