关键词: 泡型棘球蚴病, 单细胞转录组测序, 组织微环境, 转录谱特征

Abstract: Objective　To investigate the cell composition and the transcriptional characteristics in microenvironments of hepatic tissues in mice at late stage of Echinococcus multilocularis infection at a single⁃cell level. Methods　Peri⁃lesion and paired distal hepatic specimens were collected from two BALB/c mice (6 to 8 weeks old) infected with E. multilocularis for single⁃cell RNA sequencing. The Seurat package in the R software was employed for quality control of data, multi⁃sample integration and correction of batch effects, and uniform manifold approximation and projection (UMAP) algorithm was used for cell clustering. Cell types were annotated using classical marker genes. Differentially expressed genes were screened in each cell type through differential gene expression analysis, and the biological roles of cells were predicted using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Results　A total of 43 710 cells from peri⁃lesion and distal hepatic tissues of E. multilocularis⁃infected mice were analyzed, and were classified into 11 cell types, including neutrophils, T cells, macrophages, granulocyte⁃monocyte progenitor cells, B cells, plasma cells, basophils, hepatic stellate cells, endothelial cells, hepatocytes, and platelets. T cells were the largest population of immune cells in the microenvironment of hepatic tissues, including five CD4+ T cell subsets, two CD8+ T cell subsets and phosphoantigen⁃reactive γδT cells. The proportions of CD4+ helper T cells and cytotoxic CD4+ T cells decreased and the proportion of T helper 2 (Th2) cells increased in peri⁃lesion tissues relative to distal hepatic tissues. In addition, the differentially expressed genes in Th2 cells were associated with negative regulation of the immune system, and the highly expressed genes in cytotoxic CD4+ T cells correlated with activation of the immune system. Conclusions　Single⁃cell RNA sequencing deciphers the cell composition and distribution in microenvironments of hepatic tissues from mice infected with E. multilocularis, and the increased proportion of Th2 cells in peri⁃lesion hepatic tissues may be associated with formation of immunosuppressive microenvironments.

Key words: Alveolar echinococcosis, Single?cell RNA sequencing, Tissue microenvironment, Transcriptional profile