title: Neutrophil Elastase Activates Protease-activated Receptor-2 (PAR2) and Transient Receptor Potential Vanilloid 4 (TRPV4) to Cause Inflammation and Pain.
abstract: Proteases that cleave protease-activated receptor-2 (PAR(2)) at Arg(36)↓Ser(37) reveal a tethered ligand that binds to the cleaved receptor. PAR(2) activates transient receptor potential (TRP) channels of nociceptive neurons to induce neurogenic inflammation and pain. Although proteases that cleave PAR(2) at non-canonical sites can trigger distinct signaling cascades, the functional importance of the PAR(2)-biased agonism is uncertain. We investigated whether neutrophil elastase, a biased agonist of PAR(2), causes inflammation and pain by activating PAR2 and TRP vanilloid 4 (TRPV4). Elastase cleaved human PAR(2) at Ala(66)↓Ser(67) and Ser(67)↓Val(68). Elastase stimulated PAR(2)-dependent cAMP accumulation and ERK1/2 activation, but not Ca(2+) mobilization, in KNRK cells. Elastase induced PAR(2) coupling to Gαs but not Gαq in HEK293 cells. Although elastase did not promote recruitment of G protein-coupled receptor kinase-2 (GRK(2)) or β-arrestin to PAR(2), consistent with its inability to promote receptor endocytosis, elastase did stimulate GRK6 recruitment. Elastase caused PAR(2)-dependent sensitization of TRPV4 currents in Xenopus laevis oocytes by adenylyl cyclase- and protein kinase A (PKA)-dependent mechanisms. Elastase stimulated PAR(2)-dependent cAMP formation and ERK1/2 phosphorylation, and a PAR(2)- and TRPV4-mediated influx of extracellular Ca(2+) in mouse nociceptors. Adenylyl cyclase and PKA-mediated elastase-induced activation of TRPV4 and hyperexcitability of nociceptors. Intraplantar injection of elastase to mice caused edema and mechanical hyperalgesia by PAR(2)- and TRPV4-mediated mechanisms. Thus, the elastase-biased agonism of PAR(2) causes Gαs-dependent activation of adenylyl cyclase and PKA, which activates TRPV4 and sensitizes nociceptors to cause inflammation and pain. Our results identify a novel mechanism of elastase-induced activation of TRPV4 and expand the role of PAR(2) as a mediator of protease-driven inflammation and pain.
authors: From the Monash Institute of Pharmaceutical Sciences and.
authors: Peishen
authors: P
authors: Zhao
authors: From the Monash Institute of Pharmaceutical Sciences and.
authors: TinaMarie
authors: T
authors: Lieu
authors: From the Monash Institute of Pharmaceutical Sciences and.
authors: Nicholas
authors: N
authors: Barlow
authors: the Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany.
authors: Silvia
authors: S
authors: Sostegni
authors: the Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany.
authors: Silke
authors: S
authors: Haerteis
authors: the Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany.
authors: Christoph
authors: C
authors: Korbmacher
authors: the Department of Neurology, School of Medicine, Duke University, Durham, North Carolina 27710.
authors: Wolfgang
authors: W
authors: Liedtke
authors: the Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, Ontario N7L 3N6, Canada, and.
authors: Nestor N
authors: NN
authors: Jimenez-Vargas
authors: the Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, Ontario N7L 3N6, Canada, and.
authors: Stephen J
authors: SJ
authors: Vanner
authors: From the Monash Institute of Pharmaceutical Sciences and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville 3052, Australia, the Department of Pharmacology, University of Melbourne, Melbourne 3010, Australia Nigel.Bunnett@Monash.edu.
authors: Nigel W
authors: NW
authors: Bunnett
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004487:Edema / Q000378:metabolism / Q000473:pathology; D019204:GTP-Binding Proteins / Q000378:metabolism; D005727:Ganglia, Spinal / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007249:Inflammation / Q000378:metabolism*; D019272:Leukocyte Elastase / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism; D059225:Nociception; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D010146:Pain / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010447:Peptide Hydrolases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D044464:Receptor, PAR-2 / Q000378:metabolism*; D015398:Signal Transduction; D050916:TRPV Cation Channels / Q000378:metabolism*; D014982:Xenopus laevis / Q000378:metabolism
chemical_list: D044464:Receptor, PAR-2; D050916:TRPV Cation Channels; C416986:TRPV4 protein, human; C486576:Trpv4 protein, mouse; D000242:Cyclic AMP; D010447:Peptide Hydrolases; D019272:Leukocyte Elastase; D019204:GTP-Binding Proteins; D002118:Calcium
keywords: G protein-coupled receptor (GPCR); biased agonism; cell signaling; inflammation; nociception; protease; protease-activated receptor; transient receptor potential channels (TRP channels)