LRRFIP1 Inhibits White Adipocyte Differentiation by Suppressing the E2F6/C/EBPα Axis

To investigate the biological functions of the transcription factor LRR binding FLII interacting protein 1 (LRRFIP1) in white adipocyte differentiation (WAD) and elucidate the underlying molecular regulatory mechanisms involved.

Consensus clustering, differential gene expression screening, and intersection analysis were used to identify transcription factors involved in WAD. Adipogenic differentiation experiments were conducted using C3H10T1/2 cells, and a diet-induced obesity model in C57BL/6J mice was established to investigate the function of LRRFIP1 in WAD in vitro and in vivo. Molecular mechanisms were examined through quantitative real-time polymerase chain reaction, Western blotting, luciferase assays, and chromatin immunoprecipitation.

Bioinformatics analyses identified LRRFIP1 as a transcription factor associated with WAD. LRRFIP1 expression was downregulated in white adipose tissues from obese patients and in mature white adipocytes. Silencing LRRFIP1 significantly inhibited WAD in C3H10T1/2 cells and reduced differentiation biomarker expression; in contrast, overexpressing LRRFIP1 had the opposite effects. Mechanistically, LRRFIP1 bound to the E2F transcription factor 6 (E2F6) promoter to suppress E2F6 transcription, thereby downregulating a key differentiation regulator, CCAAT enhancer binding protein alpha (C/EBPα). Furthermore, in a diet-induced obesity model, LRRFIP1 could regulate the differentiation and maturation of inguinal white adipose tissue.

Our findings reveal that LRRFIP1 plays a crucial inhibitory role in WAD by negatively regulating the E2F6/C/EBPα axis. This discovery not only enriches our understanding of the molecular networks governing WAD but also holds great promise for creating targeted therapies for obesity and associated metabolic conditions.