Selective Expression of the Proprotein Convertases Furin, PC5, and PC7 in Proliferating Vascular Smooth Muscle Cells of the Rat Aorta In Vitro

• Published in: The journal of histochemistry and cytochemistry Vol. 49; no. 3; pp. 323 - 331
• Main Authors: Stawowy, Philipp, Marcinkiewicz, Jadwiga, Graf, Kristof, Seidah, Nabil G, Chretien, Michel, Fleck, Eckart, Marcinkiewicz, Mieczyslaw
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA Histochemical Soc 01-03-2001; SAGE Publications
• Subjects: Animals; Aorta - cytology; Aorta - enzymology; Blotting, Northern; Blotting, Western; Cell Count; Cell Division; Furin; Gene Expression Regulation, Enzymologic; Immunohistochemistry; Male; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - enzymology; Nerve Growth Factor - biosynthesis; Organ Culture Techniques; Proliferating Cell Nuclear Antigen - metabolism; Proprotein Convertase 5; Rats; Rats, Sprague-Dawley; RNA, Messenger - metabolism; Serine Endopeptidases - genetics; Serine Endopeptidases - metabolism; Subtilisins - genetics; Subtilisins - metabolism; Up-Regulation; aorta organ culture; α-smooth muscle cell actin; nerve growth factor; protein processing; proliferating cell nuclear; immunocytochemistry; antigen; co-localization
• ISSN: 0022-1554; 1551-5044
• DOI: 10.1177/002215540104900306

The aim of this study was to investigate whether transformation of quiescent vascular smooth muscle cells (VSMCs) into proliferating secretory cells is accompanied by an expression of processing enzymes that activate de novo-synthesized growth factors. Three enzymes belonging to the family of the kexin/subtilisin-like mammalian proprotein convertases (PCs), furin, PC5, and PC7, were found to be upregulated after balloon denudation in vivo. To determine their importance in these cell processes, we investigated their gene regulation using a short-term organ culture system. After incubation of rat aorta for 4 and 24 hr in serum-free medium, we demonstrated a significant induction of VSMC proliferation. The affected subset of VSMCs, positive for α-smooth muscle actin, also expressed proliferating cell nuclear antigen (PCNA). Our results revealed a parallel upregulation of furin, PC5, and PC7 in PCNA-immunolabeled cells. As a substrate model for comparison with PCs we used nerve growth factor (NGF). NGF is known to be activated by PCs. As shown by Northern blotting analysis, NGF mRNA concentration was significantly increased in cultured explants. NGF was released into the culture medium. In conclusion, both PCs and NGF are coordinately modulated on induction of VSMC proliferation.