Ten-eleven Translocation 2-mediated Induction of DEAD Box Helicase 5 Is Required for Early Adipogenesis (P21-077-19)

Abstract

Abstract Objectives A recent study revealed that Ten-eleven translocation methyl-cytosine dioxygenase 2 (TET2), an epigenetic regulator, is necessary for initiation of adipogenesis. This study was designed to investigate a molecular mechanism underlying TET2 function upon adipogenic induction. Methods In order to identify a direct target of TET2 in early adipogenesis, genome-wide expression profiles were examined at 4 hours after TET2 knockdown, using a 3T3-L1 differentiating model. Expression of a putative target was validated by quantitative RT-PCR. Hydroxymethyl cytosine (5hmC) was measured at the target locus with and without manipulation of TET2. Furthermore, its function in early adipogenesis was proved by siRNA knockdown and overexpression, followed by ORO staining. Results Differentially expressed genes at the early stage between the control and TET2 knockdown cells were mainly involved in cell cycle, DNA replication, and ribosome biology. It revealed that the Ddx5 gene, encoding a RNA helicase, is an early target of TET2 by showing its significantly decreased expression upon knockdown TET2. DDX5 expression was upregulated upon induction of adipogenesis and this coincided with distribution changes of 5hmC at the enhancer of the Ddx5 locus. Moreover, the 5hmC occupancy was significantly decreased upon TET2 downregulation. Functionally, DDX5 knockdown mimicked the phenotype of TET2 knockdown and DDX5 overexpression rescued it. Conclusions The findings support that DDX5 is required for early adipogenesis and its induction is mediated by TET2-exerting 5hmC. Funding Sources NRF of Korea grant (2018R1D1A1B07051274); BK21 Plus Project (22A20130012143).