title: The orphan adhesion G protein-coupled receptor GPR97 regulates migration of lymphatic endothelial cells via the small GTPases RhoA and Cdc42.
abstract: The important role of the lymphatic vascular system in pathological conditions such as inflammation and cancer has been increasingly recognized, but its potential as a pharmacological target is poorly exploited. Our study aimed at the identification and molecular characterization of lymphatic-specific G protein-coupled receptors (GPCRs) to assess new targets for pharmacological manipulation of the lymphatic vascular system. We used a TaqMan quantitative RT-PCR-based low density array to determine the GPCR expression profiles of ex vivo isolated intestinal mouse lymphatic (LECs) and blood vascular endothelial cells (BECs). GPR97, an orphan adhesion GPCR of unknown function, was the most highly and specifically expressed GPCR in mouse lymphatic endothelium. Using siRNA silencing, we found that GPR97-deficient primary human LECs displayed increased adhesion and collective cell migration, whereas single cell migration was decreased as compared with nontargeting siRNA-transfected control LECs. Loss of GPR97 shifted the ratio of active Cdc42 and RhoA and initiated cytoskeletal rearrangements, including F-actin redistribution, paxillin and PAK4 phosphorylation, and β1-integrin activation. Our data suggest a possible role of GPR97 in lymphatic remodeling and furthermore provide the first insights into the biological functions of GPR97.
authors.affiliation: From the Institute of Pharmaceutical Sciences, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland.
authors.forename: Nadejda
authors.initials: N
authors.lastname: Valtcheva
authors.forename: Adriana
authors.initials: A
authors.lastname: Primorac
authors.forename: Giorgia
authors.initials: G
authors.lastname: Jurisic
authors.forename: Maija
authors.initials: M
authors.lastname: Hollmén
authors.forename: Michael
authors.initials: M
authors.lastname: Detmar
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002465:Cell Movement; D042783:Endothelial Cells / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D020868:Gene Silencing; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism; D007422:Intestines / Q000166:cytology; D051379:Mice; D051419:Paxillin / Q000378:metabolism; D010766:Phosphorylation; D043562:Receptors, G-Protein-Coupled / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*; D054462:p21-Activated Kinases / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: C410229:Adgrg3 protein, mouse; D019012:Integrin beta1; D051419:Paxillin; D043562:Receptors, G-Protein-Coupled; C116367:PAK4 protein, human; D054462:p21-Activated Kinases; D020764:cdc42 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein
keywords: 7-Helix Receptor; Adhesion; Cytoskeleton; Endothelial Cell; Integrin; Lymphangiogenesis; Pb99; Wound Healing Assay