PLZF acetylation levels regulate NKT cell diffrentiation

The transcription factor PLZF (promyelocytic leukemia zinc finger) is encoded by the BTB domain-containing 16 (Zbtb16) gene. Its repressor function regulates specific transcriptional programs. During the development of invariant natural killer T (NKT) cells, PLZF is expressed and directs their effector program but the detailed mechanisms underlying PLZF regulation of multi-stage NKT cell developmental program are not well understood. This study investigated the role of acetylation-induced PLZF activation on NKT cell development by analyzing mice expressing a mutant form of PLZF mimicking constitutive acetylation (PLZFON mice). NKT populations in PLZFON mice were reduced in proportion and numbers of cells, and the cells present were blocked at the transition from developmental stage 1 to stage 2. NKT cell subset differentiation was also altered, with T-bet+ NKT1 and RORt+ NKT17 subsets dramatically reduced, and the emergence of a T-bet-RORt- NKT cell subset with features of cells in early developmental stages rather than mature NKT2 cells. Preliminary analysis of DNA methylation patterns suggested that activated PLZF acts on the DNA methylation signature to regulate NKT cells’ entry into the early stages of development, while repressing maturation. In wild-type NKT cells, deacetylation of PLZF is possible, allowing subsequent NKT cell differentiation. Interestingly, development of other innate lymphoid and myeloid cells, that are dependent on PLZF for their generation, is not altered in PLZFON mice highlighting lineage specific regulation. Overall, we propose that specific epigenetic control of PLZF through acetylation levels is required to regulate normal NKT cell differentiation. Key points: Constitutive acetylation of PLZF (PLZFON) blocks NKT cell development. PLZFON might act on the DNA methylation signature to control gene expression. PLZF acetylation levels regulate normal NKT cell differentiation. We investigate the transcriptional difference of iNKT cells between mice expressing a constitutive acetylated form of PLZF (PLZFon mice) vs control (WT mice) Samples WT_control_rep_1, PLZF_ON_rep_1, WT_control_rep_2 and PLZF_ON_rep_2 where used in the analyses.