title: Pivotal role of mouse mast cell protease 4 in the conversion and pressor properties of Big-endothelin-1.
abstract: The serine protease chymase has been reported to generate intracardiac angiotensin-II (Ang-II) from Ang-I as well as an intermediate precursor of endothelin-1 (ET-1), ET-1 (1-31) from Big-ET-1. Although humans possess only one chymase, several murine isoforms are documented, each with its own specific catalytic activity. Among these, mouse mast cell protease 4 (mMCP-4) is the isoform most similar to the human chymase for its activity. The aim of this study was to characterize the capacity of mMCP-4 to convert Big-ET-1 into its bioactive metabolite, ET-1, in vitro and in vivo in the mouse model. Basal mean arterial pressure did not differ between wild-type (WT) and mMCP-4(-/-) mice. Systemic administration of Big-ET-1 triggered pressor responses and increased blood levels of immunoreactive (IR) ET-1 (1-31) and ET-1 that were reduced by more than 50% in mMCP-4 knockout (-/-) mice compared with WT controls. Residual responses to Big-ET-1 in mMCP-4(-/-) mice were insensitive to the enkephalinase/neutral endopeptidase inhibitor thiorphan and the specific chymase inhibitor TY-51469 {2-[4-(5-fluoro-3-methylbenzo[b]thiophen-2-yl)sulfonamido-3-methanesulfonylphenyl]thiazole-4-carboxylic acid}. Soluble fractions from the lungs, left cardiac ventricle, aorta, and kidneys of WT but not mMCP-4(-/-) mice generated ET-1 (1-31) from exogenous Big-ET-1 in a TY-51469-sensitive fashion as detected by high-performance liquid chromatography/ matrix-assisted laser desorption/ionization-mass spectrometry. Finally, pulmonary endogenous levels of IR-ET-1 were reduced by more than 40% in tissues derived from mMCP-4(-/-) mice compared with WT mice. Our results show that mMCP-4 plays a pivotal role in the dynamic conversion of systemic Big-ET-1 to ET-1 in the mouse model.
authors.affiliation: Department of Pharmacology, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Houde
authors.forename: Marc-David
authors.initials: MD
authors.lastname: Jamain
authors.forename: Julie
authors.initials: J
authors.lastname: Labonté
authors.forename: Louisane
authors.initials: L
authors.lastname: Desbiens
authors.forename: Gunnar
authors.initials: G
authors.lastname: Pejler
authors.forename: Michael
authors.initials: M
authors.lastname: Gurish
authors.forename: Shinji
authors.initials: S
authors.lastname: Takai
authors.forename: Pedro
authors.initials: P
authors.lastname: D'Orléans-Juste
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D043422:Carboxypeptidases A / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D004351:Drug Resistance; D019332:Endothelin-1 / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D006352:Heart Ventricles / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D006439:Hemodynamics / Q000187:drug effects; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009928:Organ Specificity; D010446:Peptide Fragments / Q000097:blood / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D059748:Proteolysis / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D013876:Thiophenes / Q000494:pharmacology; D015244:Thiorphan / Q000494:pharmacology
chemical_list: D019332:Endothelin-1; D007527:Isoenzymes; D010446:Peptide Fragments; D012333:RNA, Messenger; D015842:Serine Proteinase Inhibitors; D013449:Sulfonamides; C524344:TY 51469; D013876:Thiophenes; C114932:endothelin-1 (1-31); D015244:Thiorphan; D043422:Carboxypeptidases A; D012697:Serine Endopeptidases; C066932:mast cell protease 4