Versican-thrombospondin-1 binding in vitro and colocalization in microfibrils induced by inflammation on vascular smooth muscle cells.
We identified a specific interaction between two secreted proteins, thrombospondin-1 and versican, that is induced during a toll-like receptor-3-dependent inflammatory response in vascular smooth muscle cells. Thrombospondin-1 binding to versican is modulated by divalent cations. This interaction is mediated by interaction of the G1 domain of versican with the N-module of thrombospondin-1 but only weakly with the corresponding N-terminal region of thrombospondin-2. The G1 domain of versican contains two Link modules, which are known to mediate TNFalpha-stimulated gene-6 protein binding to thrombospondin-1, and the related G1 domain of aggrecan is also recognized by thrombospondin-1. Therefore, thrombospondin-1 interacts with three members of the Link-containing hyaladherin family. On the surface of poly-I:C-stimulated vascular smooth muscle cells, versican organizes into fibrillar structures that contain elastin but are largely distinct from those formed by hyaluronan. Endogenous and exogenously added thrombospondin-1 incorporates into these structures. Binding of exogenous thrombospondin-1 to these structures, to purified versican and to its G1 domain is potently inhibited by heparin. At higher concentrations, exogenous thrombospondin-1 delays the poly-I:C induced formation of structures containing versican and elastin, suggesting that thrombospondin-1 negatively modulates this component of a vascular smooth muscle inflammatory response.
Kuznetsova
Svetlana A
SA
Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Issa
Philip
P
Perruccio
Elizabeth M
EM
Zeng
Bixi
B
Sipes
John M
JM
Ward
Yvona
Y
Seyfried
Nicholas T
NT
Fielder
Helen L
HL
Day
Anthony J
AJ
Wight
Thomas N
TN
Roberts
David D
DD
D053674:Aggrecans / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D001792:Blood Platelets / Q000378:metabolism; D004549:Elastin / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007118:Immunoassay; D066298:In Vitro Techniques; D007249:Inflammation; D051379:Mice; D020894:Microfibrils / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D011070:Poly I-C / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019700:Thrombospondin 1 / Q000235:genetics / Q000378:metabolism*; D019699:Thrombospondins / Q000378:metabolism; D051196:Toll-Like Receptor 3 / Q000378:metabolism; D053675:Versicans / Q000235:genetics / Q000378:metabolism*; D000099262:Thrombospondin 2
D053674:Aggrecans; D004549:Elastin; D011070:Poly I-C; D012333:RNA, Messenger; D019700:Thrombospondin 1; D019699:Thrombospondins; D051196:Toll-Like Receptor 3; D053675:Versicans; D000099262:Thrombospondin 2; C495344:TLR3 protein, human