title: Characterization of a mouse second leukotriene B4 receptor, mBLT2: BLT2-dependent ERK activation and cell migration of primary mouse keratinocytes.
abstract: Leukotriene B4 (LTB4) is a potent chemoattractant and activator for granulocytes and macrophages and is considered to be an inflammatory mediator. Two G-protein-coupled receptors for LTB4, BLT1 and BLT2, have been cloned from human and shown to be high and low affinity LTB4 receptors, respectively. To reveal the biological roles of BLT2 using mouse disease models, we cloned and characterized mouse BLT2. Chinese hamster ovary cells stably expressing mouse BLT2 exhibited specific binding to LTB4, LTB4-induced calcium mobilization, inhibition of adenylyl cyclase, and phosphorylation of extracellular signal-regulated kinase. We found that Compound A (4'-{[pentanoyl (phenyl) amino] methyl}-1, 1'-biphenyl-2-carboxylic acid) was a BLT2-selective agonist and induced Ca(2+) mobilization and phosphorylation of extracellular signal-regulated kinase through BLT2, whereas it had no effect on BLT1. 12-epi LTB4 exhibited a partial agonistic activity against mBLT1 and mBLT2, whereas 6-trans-12-epi LTB4 did not. Northern blot analysis showed that mouse BLT2 is expressed highly in small intestine and skin in contrast to the ubiquitous expression of human BLT2. By in situ hybridization and the reverse transcriptase polymerase chain reaction, we demonstrated that mouse BLT2 is expressed in follicular and interfollicular keratinocytes. Compound A, LTB4, and 12-epi LTB4 all induced phosphorylation of extracellular signal-regulated kinase in primary mouse keratinocytes. Furthermore, Compound A and LTB4 induced chemotaxis in primary mouse keratinocytes. These data suggest the presence of functional BLT2 in primary keratinocytes.
authors.affiliation: Departments of Biochemistry and Molecular Biology and Dermatology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Iizuka
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yokomizo
authors.forename: Kan
authors.initials: K
authors.lastname: Terawaki
authors.forename: Mayumi
authors.initials: M
authors.lastname: Komine
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tamaki
authors.forename: Takao
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002465:Cell Movement; D002633:Chemotaxis; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007249:Inflammation; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D008024:Ligands; D051379:Mice; D008956:Models, Chemical; D010766:Phosphorylation; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D018102:Receptors, Leukotriene B4 / Q000737:chemistry / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D008024:Ligands; C412867:Ltb4r2 protein, mouse; D012333:RNA, Messenger; D018102:Receptors, Leukotriene B4; D048049:Extracellular Signal-Regulated MAP Kinases; D000262:Adenylyl Cyclases; D002118:Calcium