METTL14-dependent m(6)A modification controls iNKT cell development and function

N(6)-methyladenosine (m(6)A), the most common form of RNA modification, controls CD4(+) T cell homeostasis by targeting the IL-7/STAT5/SOCS signaling pathways. The role of m(6)A modification in unconventional T cell development remains unknown. Using mice with T cell-specific deletion of RNA methyltransferase METTL14 (T-Mettl14(−/−)), we demonstrate that m(6)A modification is indispensable for iNKT cell homeostasis. Loss of METTL14-dependent m(6)A modification leads to the upregulation of apoptosis in double-positive thymocytes, which in turn decreases Vα14-Jα18 gene rearrangements, resulting in drastic reduction of iNKT numbers in the thymus and periphery. Residual T-Mettl14(−/−) iNKT cells exhibit increased apoptosis, impaired maturation, and decreased responsiveness to IL-2/IL-15 and TCR stimulation. Furthermore, METTL14 knockdown in mature iNKT cells diminishes their cytokine production, correlating with increased Cish expression and decreased TCR signaling. Collectively, our study highlights a critical role for METTL14-dependent-m(6)A modification in iNKT cell development and function.