Differential Expression of Adipocyte Transcripts in SAT and VAT between Normal Weight and Obese/Overweight Individuals

Lipogenesis is a metabolic process regulated by insulin and glucose, which governed by specific transcription factors. This study aims to explore the expression of adipocyte-specific genes in human subcutaneous (SAT) and visceral (VAT) adipose tissues among diverse populations. Anthropometric characteristics and relevant biochemical indicators were assessed in a cohort of 50 subjects from the Han population residing in Yunnan, China. The expression levels of key transcription factors (VDR, C/EBPα, PPARγ, and SREBP-1c) were quantified using real-time polymerase chain reaction (qRT-PCR) in SAT and VAT samples obtained from 20 obese/overweight patients and 30 individuals of normal weight. The results showed that among normal-weight patients, VDR mRNA levels were significantly higher in SAT compared to VAT. Conversely, in obese/overweight patients, PPARγ and SREBP-1c mRNA expressions were elevated in VAT relative to SAT. Notably, C/EBPα exhibited high expression levels in both SAT and VAT, irrespective of weight status. Spearman’s rank correlation coefficients revealed positive associations between VDR and PPARγ, as well as between PPARγ and SREBP-1c in SAT. Conversely, in VAT, VDR correlated positively with SREBP-1c, which in turn exhibited a positive correlation with PPARγ. Additionally, PPARγ demonstrated a positive correlation with C/EBPα in both SAT and VAT. In conclusion, obese/overweight individuals exhibited lower gene expression levels of VDR, PPARγ, and SREBP-1c in SAT compared to VAT. While high expression of C/EBPα may have minimal implications for obesity, it is essential for maintaining the terminal differentiation phenotype of adipocytes. Furthermore, the interaction patterns among these transcription factors varied between fat depots.