AUTHOR=Tian Cheng , Chai Jihua , Liu Weidong , Zhang Xinye , Li Yashu , Zuo Huanyan , Yuan Guohua , Zhang Haojian , Liu Huan , Chen Zhi 

TITLE=Role of the Demethylase AlkB Homolog H5 in the Promotion of Dentinogenesis

JOURNAL=Frontiers in Physiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2022.923185

DOI=10.3389/fphys.2022.923185

ISSN=1664-042X

ABSTRACT=<p>Dentinogenesis is a key process in tooth formation and is regulated by a series of pre- and post-transcriptional regulations. N6-methyl-adenosine (m<sup>6</sup>A), which is the most prevalent internal chemical modification that can be removed by the RNA demethylase AlkB homolog H5 (ALKBH5), has recently been reported to be involved in several biological processes. However, the exact function of ALKBH5-mediated m<sup>6</sup>A modification in tooth development remains unclear. Here, we showed that Alkbh5 was expressed in pre-odontoblasts, polarizing odontoblasts, and secretory odontoblasts. <italic>Alkbh5</italic> overexpression in the mouse dental papilla cell line mDPC6T promoted odontoblastic differentiation. Conditional knockout of <italic>Alkbh5</italic> in <italic>Dmp1</italic>-expressing odontoblasts led to a decrease in number of odontoblasts and increased pre-dentin formation. Mechanistically, RNA sequencing and m<sup>6</sup>A sequencing of <italic>Alkbh5</italic>-overexpressing mDPC6T cells revealed that <italic>Alkbh5</italic> promoted odontoblast differentiation by prolonging the half-life of <italic>Runx2</italic> transcripts in an m<sup>6</sup>A-dependent manner and by activating the phosphatidylinositol 3-kinase/protein kinase B pathway. Notably, the loss of Alkbh5 expression in odontoblasts impaired tertiary dentin formation <italic>in vivo</italic>. These results suggested that the RNA demethylase ALKBH5 plays a role in dentinogenesis.</p>