Mengyi Shen,1,* Leyu Zhou,1,* Xiaoli Fan,1 Ruiqi Wu,1 Shuyun Liu,2 Qiaoyu Deng,1 Yanyi Zheng,1 Jingping Liu,2 Li Yang1 

1Department of Gastroenterology and Hepatology and Laboratory of Gastrointestinal Cancer and Liver Disease, West China Hospital, Sichuan University, Chengdu, People’s Republic of China; 2NHC Key Laboratory of Transplant Engineering and Immunology, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Li Yang; Jingping Liu, Email yangli_hx@scu.edu.cn; liujingping@scu.edu.cn

Background: Autoimmune hepatitis (AIH) is a serious liver disease characterized by immune disorders, particularly effector T-cell overactivation. This study aimed to explore the therapeutic effect and underlying mechanism of mesenchymal stem cell-derived extracellular vesicle (MSC-EV) treatment on CD4+ T-cell overactivation and liver injury in AIH.
Methods: The metabolic changes of CD4+ T cells were assayed in human AIH and mouse hepatitis models. The liver protective effect of MSC-EVs was evaluated by transaminase levels, liver histopathology and inflammation. The effect of MSC-EVs on the metabolic state of CD4+ T cells was also explored.
Results: Enhanced glycolysis (eg, ~1.5-fold increase in hexokinase 2 levels) was detected in the CD4+ T cells of AIH patient samples and mouse hepatitis models, whereas the inhibition of glycolysis decreased CD4+ T-cell activation (~1.8-fold decrease in CD69 levels) and AIH liver injury (~6-fold decrease in aminotransferase levels). MSC-EV treatment reduced CD4+ T-cell activation (~1.5-fold decrease in CD69 levels) and cytokine release (~5-fold decrease in IFN-γ levels) by reducing glycolysis (~3-fold decrease) while enhancing mitochondrial oxidative phosphorylation (~2-fold increase in maximal respiration) in such cells. The degree of liver damage in AIH mice was ameliorated after MSC-EV treatment (~5-fold decrease in aminotransferase levels). MSC-EVs carried abundant mitochondrial proteins and might transfer them to metabolically reprogram CD4+ T cells, whereas disrupting mitochondrial transfer impaired the therapeutic potency of MSC-EVs in activated CD4+ T cells.
Conclusion: Disordered glucose metabolism promotes CD4+ T-cell activation and associated inflammatory liver injury in AIH models, which can be reversed by MSC-EV therapy, and this effect is at least partially dependent on EV-mediated mitochondrial protein transfer between cells. This study highlights that MSC-EV therapy may represent a new avenue for treating autoimmune diseases such as AIH.

Keywords: autoimmune hepatitis, extracellular vesicles, metabolic reprogramming, mitochondria, inflammation