Localization of cysteine protease, cathepsin S, to the surface of vascular smooth muscle cells by association with integrin alphanubeta3.
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.
Cheng
Xian Wu
XW
Department of Geriatrics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
Kuzuya
Masafumi
M
Nakamura
Kae
K
Di
Qun
Q
Liu
Zexuan
Z
Sasaki
Takeshi
T
Kanda
Shigeru
S
Jin
Hai
H
Shi
Guo-Ping
GP
Murohara
Toyoaki
T
Yokota
Mitsuhiro
M
Iguchi
Akihisa
A
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
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