Gut‐derived lymphocyte recruitment to liver and induce liver injury in non‐alcoholic fatty liver disease mouse model

Background and Aim Most studies focus on gut-derived factors like microbiota and its products and how they contribute to non-alcoholic fatty liver disease (NAFLD) progression. This study investigated whether the gut-derived lymphocytes could migrate to the liver and induce liver injury in NAFLD. Methods A high-fat diet induced an NAFLD mouse model, and lymphocytes were labeled with 1,1-dioctadecyl-3,3,3,3 tetramethylindotricarbocyanine iodide and carboxy-fluorescein succinimidyl ester, respectively, and intravenously injected to mice to monitor lymphocyte migration. Results Adoptive transfer model results indicated that compared with lymphocytes from the spleen, bone marrow and thymus of NAFLD donor mice, mesenteric lymph nodes (MLN) cells from NAFLD donor mice predominately accumulated in the livers of NAFLD recipient mice. The frequencies of central memory CD4+T and CD8+T cells in livers of NAFLD mice were significantly increased; however, the activated T cells were not significantly altered. After adoptively transferred MLN cells, the frequencies of the activated CD4+T and CD8+T cells increased in livers of NAFLD recipient mice. By contrast, the frequencies of central memory and naive CD4+T and CD8+T cells decreased. MLN cells also induced liver injury in NAFLD recipient mice, as reflected by elevated serum alanine aminotransferase and glutamic oxaloacetic transaminase serums. Moreover, the chemotaxis assay showed that CCL5 mediated the MLN cell migration to the liver. Also, blocking the CCL5 inhibited MLN cell migration to the liver in vitro. Conclusions Gut-derived lymphocytes from NAFLD mice could migrate to the liver and induce liver injury and hepatic CD4+T and CD8+T cells activation. The migration was associated with the upregulation of CCL5 in the liver.