14-3-3ζ regulates adipogenesis by modulating chromatin accessibility during the early stages of adipocyte differentiation

Abstract

We previously established the scaffold protein 14-3-3{zeta} as a critical regulator of adipogenesis and adiposity, but the temporal specificity of its action during adipocyte differentiation remains unclear. To decipher if 14-3-3{zeta} exerts its regulatory functions on mature adipocytes or on adipose precursor cells (APCs), we generated Adipoq14-3-3{zeta}KO and Pdgfra14-3-3{zeta}KO mouse models. Our findings revealed a pivotal role for 14-3-3{zeta} in APC differentiation in a sex-dependent manner, whereby male and female Pdgfra14-3-3{zeta}KO mice display impaired or potentiated weight gain, respectively, as well as fat mass. To better understand how 14-3-3{zeta} regulates the adipogenic transcriptional program in APCs, CRISPR-Cas9 was used to generate TAP-tagged 14-3-3{zeta}-expressing 3T3-L1 preadipocytes. Using these cells, we examined if the 14-3-3{zeta} nuclear interactome is enriched with adipogenic regulators during differentiation. Regulators of chromatin remodeling, such as DNMT1 and HDAC1, were enriched in the nuclear interactome of 14-3-3{zeta}, and their activities were impacted upon 14-3-3{zeta} depletion. The interactions between 14-3-3{zeta} and chromatin-modifying enzymes suggested that 14-3-3{zeta} may control chromatin remodeling during adipogenesis, and this was confirmed by ATAC-seq, which revealed that 14-3-3{zeta} depletion impacted the accessibility of up to 1,244 chromatin regions corresponding in part to adipogenic genes, promoters, and enhancers during the initial stages of adipogenesis. Moreover, 14-3-3{zeta}-dependent chromatin accessibility was found to directly correlate with the expression of key adipogenic genes. Altogether, our study establishes 14-3-3{zeta} as a crucial epigenetic regulator of adipogenesis and highlights the usefulness of deciphering the nuclear 14-3-3{zeta} interactome to identify novel pro-adipogenic factors and pathways.