PPARδ

PPARδ (peroxisome proliferator-activated receptor delta, PPARD) is a ligand-activated nuclear receptor that functions as a transcription factor and regulates gene networks involved in lipid metabolism, glucose homeostasis, cellular differentiation, proliferation, and survival through heterodimerization with retinoid X receptor (RXR)^[1][2]. Mechanistically, PPARδ integrates lipid-derived signaling with transcriptional control and modulates the expression of target genes in a ligand-dependent or ligand-independent manner, thereby influencing energy metabolism and cellular responses across multiple tissues^[3][4]. PPARδ is particularly associated with fatty acid utilization, mitochondrial function, and metabolic adaptation, and its activity has been linked to the regulation of cardiac lipid metabolism and fuel switching in metabolically active tissues^[5][6]. In disease models, PPARδ has been investigated in metabolic syndrome, cardiovascular disease, neuroinflammation, neurodegeneration, dyslipidemia, diabetes, and cancer, reflecting its broad physiological and pathological relevance^[1][7]. Compared with related isoforms, PPARα primarily coordinates fatty-acid β-oxidation in liver and other oxidative tissues, whereas PPARγ is a master regulator of adipogenesis and insulin sensitivity; in contrast, PPARδ exhibits broader tissue distribution and distinct functions in energy metabolism, cell fate determination, and tissue-specific transcriptional regulation^[1][3][6]. For experimental applications, selective PPARδ agonists are widely used to investigate metabolic regulation because receptor activation enhances fatty acid metabolism and promotes metabolic adaptations associated with improved energy utilization^[7][8]. The availability of synthetic agonists and highly selective ligands has therefore made PPARδ a valuable target for mechanistic studies of metabolic and inflammatory pathways^[1][8].