title: Localization of cysteine protease, cathepsin S, to the surface of vascular smooth muscle cells by association with integrin alphanubeta3.
abstract: Smooth muscle cell (SMC) migration from the tunica media to the intima, a key event in neointimal formation, requires proteolytic degradation of elastin-rich extracellular matrix barriers. Although cathepsin S (Cat S) is overexpressed in atherosclerotic and neointimal lesions, its exact role in SMC behavior remains primarily unresolved. We examined the involvement of Cat S on SMC migration through an extracellular matrix barrier and its localization in SMCs. A selective Cat S inhibitor and the endogenous inhibitor cystatin C significantly attenuated SMC invasion across elastin gel. Western blotting and cell surface biotinylation analysis demonstrated localization of the 28-kd active form of Cat S on the SMC surface, consistent with its role in the proteolysis of subcellular matrices. Treatment with interferon-gamma or interleukin-beta1 significantly augmented the ability of SMC membranes to degrade elastin along with a significant increase in the level of active Cat S compared with controls. Immunofluorescence and confocal microscopy showed a punctuated pattern of Cat S clusters at the periphery of SMCs; further studies demonstrated partial co-localization of Cat S and integrin alphanubeta3 at the cell surfaces. These findings demonstrate that active Cat S co-localizes with integrin alphanubeta3 as a receptor on the SMC surface, playing an important role in the invasive behavior of SMCs.
authors.affiliation: Department of Geriatrics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
authors.forename: Xian Wu
authors.initials: XW
authors.lastname: Cheng
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kuzuya
authors.forename: Kae
authors.initials: K
authors.lastname: Nakamura
authors.forename: Qun
authors.initials: Q
authors.lastname: Di
authors.forename: Zexuan
authors.initials: Z
authors.lastname: Liu
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kanda
authors.forename: Hai
authors.initials: H
authors.lastname: Jin
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Shi
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Murohara
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yokota
authors.forename: Akihisa
authors.initials: A
authors.lastname: Iguchi
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D019921:Biotinylation; D015153:Blotting, Western; D002403:Cathepsins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D002478:Cells, Cultured; D055316:Cystatin C; D015891:Cystatins / Q000494:pharmacology; D004549:Elastin / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D047468:Immunoprecipitation; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D018613:Microscopy, Confocal; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013347:Subcellular Fractions; D017539:Tunica Intima / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C525030:CST3 protein, human; C525032:Cst3 protein, rat; D055316:Cystatin C; D015891:Cystatins; D039302:Integrin alphaVbeta3; D007375:Interleukin-1; D012333:RNA, Messenger; D007371:Interferon-gamma; D004549:Elastin; D002403:Cathepsins; C028217:cathepsin S