The PCR primers of constructed vectors.

Peroxisome proliferator-activated receptor α (PPARα) is a crucial transcription factor in regulating brown adipose tissue (BAT) physiological function. However, the mechanisms of enhancer-promoter chromatin interactions that control transcription regulation of Pparα in BAT remain unclear. In this study, we used circularized chromosome conformation capture coupled with next-generation sequencing (4C-seq) to reveal distinct differences in Pparα-associated chromatin interactions between intrascapular BAT (iBAT) and epididymal white adipose tissue (eWAT). In addition, we identified an iBAT-specific active enhancer (Pparα-En4) that was activated by cold stimulation. Functional assays demonstrated that targeted repression of Pparα-En4 region significantly decreased Pparα expression and impaired brown adipocyte differentiation and thermogenesis. Moreover, the transcription factor CREB regulated Pparα-En4 activity and increased Pparα expression in cooperation with the acetyltransferase CBP. Repression of Pparα-En4 using a lentiviral system in iBAT resulted in reduced thermogenic capacity and mitochondrial damage during cold acclimation conditions in vivo. These findings reveal that Pparα-En4 is a critical regulatory element in thermogenesis and mitochondrial function, and provide important insights into enhancer-mediated transcriptional regulation of Pparα expression in BAT.