title: Characterization of Substance P processing in mouse spinal cord S9 fractions using high-resolution Quadrupole-Orbitrap mass spectrometry.
abstract: Tachykinins are a family of pronociceptive neuropeptides with a specific role in pain and inflammation. Several mechanisms regulate endogenous tachykinins and Substance P (SP) levels, including the differential expression of protachykinin mRNA and the controlled secretion of tachykinins from neurons. Proteolysis is suspected to regulate extracellular SP concentrations but few studies were conducted on the metabolism of proneuropeptides and neuropeptides. Here, we provide evidence that proteolysis controls SP levels in the spinal cord leading to the formation of active C-terminal fragments. Using high-resolution mass spectrometry, specific tachykinins fragments were characterized and quantified. The metabolic stability of β-Tachykinin58-71and SP were very short resulting in half-life of 5.7 and 3.5min respectively. Several C-terminal fragments were identified, including SP3-11, SP5-11and SP8-11, which conserve affinity for the Neurokinin 1 receptor. Interestingly, the metabolic stability of C-terminal fragments was significantly superior. Two specific Prolyl endopeptidase inhibitors were used and showed a significant reduction in the rate of formation of SP3-11and SP5-11providing strong evidence that Prolyl endopeptidase is involved into N-terminal processing of SP in the spinal cord.
authors.affiliation: Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
authors.forename: Mouna
authors.initials: M
authors.lastname: Saidi
authors.affiliation: Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
authors.forename: Soufiane
authors.initials: S
authors.lastname: Kamali
authors.affiliation: Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada. Electronic address: francis.beaudry@umontreal.ca.
authors.forename: Francis
authors.initials: F
authors.lastname: Beaudry
mesh_terms: D000818:Animals; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D010446:Peptide Fragments / Q000494:pharmacology*; D011498:Protein Precursors / Q000493:pharmacokinetics*; D059748:Proteolysis / Q000187:drug effects; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D013373:Substance P / Q000494:pharmacology*; D015320:Tachykinins / Q000493:pharmacokinetics*
chemical_list: D010446:Peptide Fragments; D011498:Protein Precursors; D015320:Tachykinins; C054618:protachykinin; D013373:Substance P
keywords: Mass spectrometry; Pain; Prolyl endopeptidase (PREP); Proteolysis; S9 fractions; SP(3–11); SP(5–11); Spinal cords; Substance P; Tachykinin; β-Tachykinin(58–71)