CD1d-restricted pathways in hepatocytes control local natural killer T cell homeostasis and hepatic inflammation
Proceedings of the National Academy of Sciences of the United States of America
National Academy of Sciences
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Zeissig, S., Peuker, K., Iyer, S., Gensollen, T., Dougan, S., Olszak, T., Kaser, A., & et al. (2017). CD1d-restricted pathways in hepatocytes control local natural killer T cell homeostasis and hepatic inflammation. Proceedings of the National Academy of Sciences of the United States of America, 114 (39), 10449-10454. https://doi.org/10.1073/pnas.1701428114
Invariant natural killer T (iNKT) cells recognize lipid antigens presented by CD1d and play a central role in regulating immunity and inflammation in peripheral tissues. However, the mechanisms which govern iNKT cell homeostasis after thymic emigration are incompletely understood. Here we demonstrate that microsomal triglyceride transfer protein (MTP), a protein involved in the transfer of lipids onto CD1d, regulates liver iNKT cell homeostasis in a manner dependent on hepatocyte CD1d. Mice with hepatocyte-specific loss of MTP exhibit defects in the function of CD1d and show increased hepatic iNKT cell numbers as a consequence of altered iNKT cell apoptosis. Similar findings were made in mice with hepatocyte-specific loss of CD1d confirming a critical role of CD1d in this process. Moreover, increased hepatic iNKT cell abundance in the absence of MTP is associated with susceptibility to severe iNKT cell-mediated hepatitis thus demonstrating the importance of CD1d-dependent control of liver iNKT cells in maintaining immunological homeostasis in the liver. Together, these data demonstrate an unanticipated role of parenchymal cells, as shown here for hepatocytes, in tissue-specific regulation of CD1d-restricted immunity and further suggest that alterations in lipid metabolism may affect iNKT cell homeostasis through effects on CD1d-associated lipid antigens.
CD1d, NKT cells, hepatocyte
Work was supported by: The Deutsche Forschungsgemeinschaft (DFG) (ZE814/5-1), the European Research Council (ERC Starting Grant agreement n°336528), the Crohn’s and Colitis Foundation of America (Postdoctoral Fellowship Award), the European Commission (Marie Curie International Reintegration Grant n°256363), and the DFG Excellence Clusters “Inflammation at Interfaces” and “Center for Regenerative Therapies ” (S.Z.) and NIH grants DK044319, DK051362, DK053056, DK088199 and the Harvard Digestive Diseases Center (HDDC) (DK0034854) (R.S.B.).
External DOI: https://doi.org/10.1073/pnas.1701428114
This record's URL: https://www.repository.cam.ac.uk/handle/1810/270138