This group of G protein-coupled receptors share lipid mediators as ligands. Lipid mediators are bioactive lipids, such as lysophospholipids (and their derivatives) and arachidonic acid-derived eicosanoids. Class 1 lipid mediators include lysophosphatidic acid (LPA), sphingosine-1-phosphate (SIP), and endocannabinoids. Receptors for LPA are involved in brain development, embryo implantation, and hair growth. Importantly, they have also been linked to neuropathic pain and pulmonary fibrosis. SIP receptors are regulators of developmental vascular integrity, anaphylaxis and leukocyte egress from lymphoid organs. Additionally, SIP receptors have been shown to be associated with cancer.
Class 2 lipid mediators are eicosanoids, such as prostaglandins and leukotrienes, that are produced from arachidonic acid via cyclooxygenase (COX) and lipoxygenase (LOX) pathways. Prostaglandins are associated with diverse physiological and pathological pathways. For example, PGD2 regulates sleep, allergy, and adiposity, while PGE2 is a regulator of inflammation, fever, pain, and tumorigenesis. Leukotrienes, such as leukotriene B4, are critical mediators of asthma. Further studies into lipid mediators and their receptors will be crucial, as they have been linked to inflammation, infertility, atherosclerosis, ischemia, metabolic syndrome, and cancer. R&D Systems offers antibodies for the receptors listed below, as well as agonists for the cannabinoid receptors.