Direct molecular target of fibrate lipid-lowering drugs (fenofibrate, pemafibrate, gemfibrozil) & pan-PPAR MASH agonist lanifibranor
Gene Structure & Expression
Genomic Organization & Cytogenetic Locus: 8-exon gene spanning ~93 kb on chromosome 22q13.31, encoding a 468-amino-acid nuclear receptor comprising an N-terminal ligand-independent AF-1 domain, a two-zinc-finger DNA-binding domain, a hinge region, and a spacious C-terminal Y-shaped hydrophobic ligand-binding pocket (AF-2).
Cellular & Tissue Expression Profile: Highly expressed in tissues with high rates of mitochondrial and peroxisomal fatty acid catabolism: hepatic hepatocytes, renal proximal tubule epithelium, cardiac myocytes, oxidative skeletal muscle fibers, and brown adipocytes.
Molecular Function & Pathways
Biochemical & Physiological Mechanism: Obligate heterodimer with Retinoid X Receptor Alpha (RXRA) bound to 5-prime-AGGTCANAGGTCA-3-prime direct-repeat-1 (DR1) peroxisome proliferator response elements (PPREs); when activated during fasting by adipose-derived free fatty acids or hepatocyte FASN-synthesized 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (16:0/18:1-GPC) alongside coactivator PGC-1alpha (PPARGC1A), PPAR-alpha transcriptionally induces CPT1A, ACADM, ACOX1, HMGCS2 (ketogenesis), FGF21, APOA1, APOA5, and LPL while repressing APOC3 and NF-kappaB inflammation.
Clinical & Therapeutic Significance
Human Genetic Variants & Disease Phenotypes: Loss of PPARA function impairs the adaptive transition to fasting—causing hypoketotic hypoglycemia, severe hepatic steatosis, and hypothermia upon caloric deprivation—while the human coding variant p.Leu162Val (rs1800206) modulates plasma triglyceride and ApoC-III responses to dietary polyunsaturated fatty acids and fibrate therapy.
Therapeutic & Clinical Pharmacology: Direct molecular target of fibric acid derivatives (fenofibrate, gemfibrozil, bezafibrate) and the selective PPAR-alpha modulator (SPPARM-alpha) pemafibrate, which lower plasma triglycerides by 30–50% and raise HDL-cholesterol, as well as dual/pan-PPAR agonists (elafibranor, saroglitazar, lanifibranor) used in primary biliary cholangitis and MASH.