title: Inactivation of endothelial proprotein convertase 5/6 decreases collagen deposition in the cardiovascular system: role of fibroblast autophagy.
abstract: Proprotein convertase (PC) 5/6 belongs to a family of secretory proteases involved in proprotein proteolysis. Several studies suggest a role for PC5/6 in cardiovascular disease. Because lethality at birth of mice lacking PC5/6 precluded elucidation of its function in the adult, we generated mice in which the gene of PC5/6 (pcsk5) is specifically inactivated in endothelial cells (ecKO), which are viable and do not exhibit overt abnormalities. In order to uncover the function of PC5/6 in the cardiovascular system, the effect of ecKO was studied in aging mice. In 16 to 18-month-old ecKO mice, the left ventricle (LV) mass, media cross-sectional area of aorta and coronary arteries, and media-to-lumen ratio of mesenteric arteries were decreased. The LV presented decreased diastolic function, and mesenteric arteries showed decreased stiffness. Collagen was decreased in the LV myocardial interstitium and perivascularly in coronary arteries and aorta. Cardiovascular hypotrophy likely develops with aging, since no significant changes were observed in 2-month-old ecKO mice. Fibroblasts, as a source of collagen in myocardium and vasculature, may play a role in the decrease in collagen deposition. Fibroblasts co-cultured with ecKO endothelial cells showed decreased collagen production, decreased insulin-like growth factor (IGF)-1/Akt/mTOR signaling, and enhanced autophagic activation. PC5/6 inactivation in endothelial cells results in cardiovascular hypotrophy associated with decreased collagen deposition, decreased LV diastolic function, and vascular stiffness, suggesting a trophic role of endothelial PC5/6 in the cardiovascular system, likely mediated by IGF-1/Akt/mTOR signaling and control of autophagy.
authors.affiliation: Lady Davis Institute for Medical Research, Montreal, Quebec, Canada.
authors.forename: Chiara
authors.initials: C
authors.lastname: Marchesi
authors.forename: Rachid
authors.initials: R
authors.lastname: Essalmani
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Lemarié
authors.forename: Eyal
authors.initials: E
authors.lastname: Leibovitz
authors.forename: Talin
authors.initials: T
authors.lastname: Ebrahimian
authors.forename: Pierre
authors.initials: P
authors.lastname: Paradis
authors.forename: Nabil G
authors.initials: NG
authors.lastname: Seidah
authors.forename: Ernesto L
authors.initials: EL
authors.lastname: Schiffrin
authors.forename: Annik
authors.initials: A
authors.lastname: Prat
mesh_terms: D000818:Animals; D001343:Autophagy; D003094:Collagen / Q000096:biosynthesis* / Q000235:genetics; D003331:Coronary Vessels / Q000378:metabolism* / Q000473:pathology; D042783:Endothelial Cells / Q000201:enzymology* / Q000473:pathology; D005347:Fibroblasts / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009929:Organ Size / Q000235:genetics; D045702:Proprotein Convertase 5 / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D059289:Vascular Stiffness
chemical_list: D007334:Insulin-Like Growth Factor I; D003094:Collagen; C546843:mTOR protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D045702:Proprotein Convertase 5; C473805:propeptide convertase 5, mouse