H3K36me3 Modification by SETD2 is Essential for Col11a2 and Sema3e Transcription to Maintain Dentinogenesis in Mice

Dentin is a major mineralized component of teeth generated by odontoblasts. Several types of histone methylation have been reported to play important roles in odontoblast differentiation and dentinogenesis. However, the role of methylation on histone 3 at lysine 36 (H3K36) remains enigmatic. Here we find a high expression of SETD2, a methyltransferase catalyzing the trimethylation of H3K36 (H3K36me3), in the odontoblast layer. In vitro knockdown experiments and in vivo observations of two conditional knockout mouse models reveal SETD2 is essential for odontoblast differentiation and dentinogenesis. Integrated analyses of RNA sequencing and Spike-in Cleavage Under Targets and Tagmentation sequencing data show SETD2 is crucial for both H3K36me3 occupancy on the loci of Col11a2 and Sema3e and their transcription. Further experiments verify COL11A2 and SEMA3E act upstream of AKT1 signaling, promoting odontoblastic differentiation. In vitro and in vivo activation of AKT1 using SC79 (an AKT activator) partially rescues the impaired odontoblast differentiation caused by Setd2 knockdown or deficiency. Therefore, our findings indicate that H3K36me3 mediated by SETD2 is essential for dentinogenesis through regulating the expression of Col11a2 and Sema3e and AKT1 signaling.