Hydroxycarboxylic Acid Receptor 2 (HCAR2) Antibody

Background

HCAR2, also known as GPR109A, is a G protein-coupled receptor activated by nicotinic acid (niacin) and endogenous metabolites such as β-hydroxybutyrate (BHB). It is highly expressed in adipose tissue, immune cells, and the gut, where it plays a pivotal role in lipid metabolism, inflammation, and energy homeostasis. In adipocytes, HCAR2 activation inhibits cAMP production via Gi/o proteins, leading to the suppression of lipolysis and reduced free fatty acid release, which lowers circulating triglyceride levels. HCAR2 also mediates anti-inflammatory effects in immune cells, particularly in macrophages, by inhibiting pro-inflammatory cytokine production and promoting anti-inflammatory pathways, making it a key target in atherosclerosis and inflammatory diseases. HCAR2 is activated during fasting or ketogenic states through β-hydroxybutyrate, linking it to metabolic adaptations and energy conservation. Dysregulation of HCAR2 is implicated in metabolic disorders, cardiovascular disease, and neuroinflammation. Niacin-based therapies targeting HCAR2 are used to improve lipid profiles and manage dyslipidemia, highlighting its clinical relevance.