title: Lysophosphatidic acid reduces the organ injury caused by endotoxemia-a role for G-protein-coupled receptors and peroxisome proliferator-activated receptor-gamma.
abstract: Exogenous lysophosphatidic acid (LPA) has been shown to beneficial in renal ischemia/reperfusion injury, wound healing and colitis. LPA acts via specific G-protein-coupled receptors and also peroxisome proliferator-activated receptor-gamma (PPAR-gamma). However, activation of PPAR-gamma is dependent on the presence of an unsaturated acyl chain. Here we investigate the effects of saturated LPA (18:0) and unsaturated LPA (18:1) on the organ injury associated with endotoxemia and the receptors mediating LPA activity. Male Wistar rats received either lipopolysaccharide (LPS, 6 mg/kg i.v.) or vehicle. The PPAR-gamma antagonist GW9662 (1 mg/kg i.v.), the LPA receptor antagonist Ki16425 (0.5 mg/kg i.v.) or vehicle was administered 30 min after LPS. LPA 18:0 or LPA 18:1 (1 mg/kg i.v.) or vehicle was administered 1 h after injection of LPS. Endotoxemia for 6 h resulted in an increase in serum levels of aspartate aminotransferase, alanine aminotransferase and creatine kinase. Therapeutic administration of LPA 18:0 or 18:1 reduced the organ injury caused by LPS. LPA 18:0 also attenuated the increase in plasma IL-1beta caused by LPS. Ki16425, but not GW9662, attenuated the beneficial effects of LPA 18:0, however, Ki16425 and GW9662 attenuated the beneficial effects of 18:1. In conclusion, LPA reduces the organ injury caused by endotoxemia in the rat. Thus, LPA may be useful in the treatment of shock of various aetiologies. The mechanism of action is related to acyl chain saturation, with LPA 18:0 acting via G-protein-coupled receptors and LPA 18:1 acting via G-protein-coupled receptors and PPAR-gamma.
authors.affiliation: Centre for Experimental Medicine, Nephrology & Critical Care, The William Harvey Research Institute, St. Bartholomew's and The Royal London School of Medicine and Dentistry, Queen Mary, University of London, United Kingdom.
authors.forename: Oliver
authors.initials: O
authors.lastname: Murch
authors.forename: Marika
authors.initials: M
authors.lastname: Collin
authors.forename: Christoph
authors.initials: C
authors.lastname: Thiemermann
mesh_terms: D000818:Animals; D002318:Cardiovascular Diseases / Q000473:pathology*; D019446:Endotoxemia / Q000473:pathology*; D008099:Liver / Q000201:enzymology / Q000473:pathology; D008246:Lysophospholipids / Q000502:physiology*; D008297:Male; D009468:Neuromuscular Diseases / Q000201:enzymology / Q000473:pathology; D047495:PPAR gamma / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000502:physiology*
chemical_list: D008246:Lysophospholipids; D047495:PPAR gamma; D043562:Receptors, G-Protein-Coupled; C032881:lysophosphatidic acid