Non-alcoholic steatohepatitis causes selective CD4+ T cell loss and promotes hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the second most common cause of cancer related death. NAFLD affects a large proportion of the US population. Its incidence and prevalence are increasing to epidemic proportions around the world and is known to increase the risk of HCC. We studied how intrahepatic lipids affect adaptive immunity and HCC development in different murine models of NASH and HCC. Linoleic acid, a fatty acid found in NAFLD caused a selective loss of hepatic CD4+ but not CD8+ T cells leading to accelerated hepatocarcinogenesis. CD4+ T cells were more dependent on oxidative phosphorylation for energy source than CD8+ T cells, and disruption of oxidative phosphorylation by linoleic acid caused more severe damage in CD4+ T cells leading to selective loss of these cells. In vivo blockade of ROS using n-acetylcysteine reversed the NASH-induced hepatic CD4+ T cell decrease and delayed NASH-promoted HCC. Our results provide a new link between lipid metabolism and impaired anti-tumor surveillance.

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Ma C, Kesarwala AH, Eggert T, Medina-Echeverz J, Kleiner DE, Jin P, Stroncek DF, Terabe M, Kapoor V, ElGindi M, Han M, Thornton AM, Zhang H, Egger M, Luo J, Felsher DW, McVicar DW, Weber A, Heikenwalder M, Greten TF