Single-cell transcriptomes identifies characteristic features of mouse macrophages in liver Mallory-Denk bodies formation

Mallory-Denk bodies (MDBs) consist of intracellular aggregates of misfolded proteins in ballooned hepatocytes and serve as important markers of progression in certain liver diseases. Resident hepatic macrophage-mediated inflammation influences the development of chronic liver diseases and cancer. Here, the first systematic study of macrophages heterogeneity in mice was conducted to illustrate the pathogenesis of MDB formation using single-nucleus RNA sequencing (snRNA-seq). Furthermore, we provided transcriptional profiles of macrophages obtained from the fractionation of mouse liver tissues following chronic injury. We equally identified seven discrete macrophage subpopulations, each involved in specific cellular activated pathways such as basal metabolism, immune regulation, angiogenesis, and cell cycle regulation. Among these, a specific macrophage cluster (Cluster4), a subpopulation specifically expressing genes that regulate cell division and the cell cycle, was identified. Interestingly, we found that CCR2 was significantly induced in Cluster2, thereby inducing monocytes to migrate to macrophages to promote MDB pathogenesis. Thus, our study is the first to demonstrate the heterogeneity of macrophages associated with liver MDB formation in mice through single-cell resolution. This serves as the basis for further insights into the pathogenesis of liver MDB formation and molecular mechanisms of chronic liver disease progression.