MiR150 over-expression impairs iNKT cell development, maturation, and function

CD1d-restricted invariant natural killer T (iNKT) cells play an important role in the regulation of diverse immune responses. MicroRNAs have been shown to be critically involved in iNKT cell development, maturation, and function, but the roles of specific miRNAs in it remain not completely understood. We had previously shown the dynamic upregulation of miR-150 during thymus iNKT cell maturation and identified the interrupted iNKT final stage maturation and elevated IFNγ production in miR-150KO mice. To determine the requirement of dynamic expressional changes of miR150 during iNKT cell development, we generated thymus-specific miR150 knock in mice (miR-150KI). MiR-150 over expression resulted in reduced overall iNKT cell number in both thymus and periphery, which could be related to increased apoptosis. MiR-150KI thymus iNKT cells showed the blockade of iNKT maturation at multiple maturation transition points. Splenic iNKT with miR-150KI displayed interrupted maturation and reduced cytokine production, including IFNγ, IL-4, and TNFα, upon in vitro stimulation. Furthermore, Bone marrow chimera study confirmed the effect of miR-150KI on iNKT cell development, maturation, and function are cell autonomous. Altogether, our results indicated that the tight control of miR150 expression is required in iNKT cell development and function. Detailed molecular mechanisms of miR-150 mediated iNKT cell regulation in different developmental stages and activation status are currently under investigation. Copyright © 2017 by The American Association of Immunologists, Inc