TG-interacting factor 1 regulates mitotic clonal expansion during adipocyte differentiation

• Published in: Biochimica et biophysica acta. Molecular and cell biology of lipids 2024-06, Vol.1869 (5), p.159492, Article 159492
• Main Authors: Chang, Yu-Hao, Tseng, Yu-Hua, Wang, Ju-Ming, Tsai, Yau-Sheng, Huang, Huei-Sheng
• Format: Article
• Language: English
• Subjects: Adipogenesis; C/EBPβ; p27kip1; PPARγ; TGIF1
• ISSN: 1388-1981; 1879-2618; 1879-2618
• DOI: 10.1016/j.bbalip.2024.159492

Obesity is one of the significant health challenges in the world and is highly associated with abnormal adipogenesis. TG-interacting factor 1 (TGIF1) is essential for differentiating murine adipocytes and human adipose tissue-derived stem cells. However, the mode of action needs to be better elucidated. To investigate the roles of TGIF1 in differentiation in-depth, CRISPR/Cas9 knockout technology was performed to generate TGIF1-silenced preadipocytes. The absence of TGIF1 in 3 T3-F442A preadipocytes abolished lipid accumulation throughout the differentiation using Oil Red O staining. Conversely, we established 3 T3-F442A preadipocytes stably expressing TGIF1 and doxycycline-inducible TGIF1 in TGIF1-silenced 3 T3-F442A preadipocytes. Remarkably, the induction of TGIF1 by doxycycline during the initial differentiation phase successfully promoted lipid accumulation in TGIF1-silenced 3 T3-F442A cells. We further explored the mechanisms of TGIF1 in early differentiation. We demonstrated that TGIF1 promoted the mitotic clonal expansion via upregulation of CCAAT/enhancer-binding proteins β expression, interruption with peroxisome proliferators activated receptor γ downstream regulation, and inhibition of p27kip1 expression. In conclusion, we strengthen the pivotal roles of TGIF1 in early differentiation, which might contribute to resolving obesity-associated metabolic syndromes. •We demonstrated that TGIF1 was essential for early differentiation by using several advanced techniques in preadipocytes, including enforced overexpression, CRISPR/Cas9 knockout, and Tet-inducible gene expression.•TGIF1 contributes to the early differentiation through novel mechanisms, including upregulation of C/EBPβ expression, interference in PPARγ downstream regulation, and inhibition of p27kip1 expression, thereby promoting mitotic clonal expansion in the early differentiation.•We conclude that p27kip1, a PPARγ-regulated gene, is suppressed by TGIF1 in early differentiation until the endogenous PPARγ ligands production which is tightly linked to mitotic clonal expansion to strengthen the binding ability of PPARγ to the promoter of p27kip1 and stop the cell cycle to proceed to differentiation.