Table 3 Interactions between extracellular matrix (ECM) proteins and fibroblast-like synoviocytes (FLS)

Laminin (Ln)

Ln is synthesized in rat and human FLS, and is involved in FLS adhesion

FLS adhesion to Ln shows enhanced proliferative ability in response to PDGF

RA-FLS bind to Ln more strongly than normal FLS, with monoclonal antibodies to integrin α 3, α 6,

β 1 subunits partly blocking this adhesion

Fibronectin (Fn)

FLS plated on the substrate containing Fn show extensive focus formation, and enhanced adhesion

and proliferation

CS-1 Fn correlates with FLS proliferation

ED-A Fn is associated with activation of FLS

FLS adhering to Fn show higher proliferative ability in response to PDGF

Adhesion to Fn through integrin α 5β 1 downregulates the collagenase expression in human FLS

RA-FLS bind more strongly to Fn than normal FLS; anti-α 5, or β 1 monoclonal antibodies block the

adhesion

Rabbit FLS cultured on the substrate containing Fn fragment show upregulated expression of

procollagenase and prostromelysin

Vitronectin (Vn)

FLS adhering to Vn shows higher proliferative ability in response to PDGF. Adhesion to Vn through

integrin α v downregulates collagenase expression in human FLS

Tenascin (Tn)

FLS synthesize Tn

RA-FLS bind more strongly to Tn than normal FLS; monoclonal antibodies to integrin β 1 block adhesion

Rabbit FLS cultured on Tn/Fn mixed substrate show increased expression of collagenase, stromelysin,

the 92 kDa gelatinase, and c-fos

Hyaluronan (HA)

Synthesized by FLS, degraded by macrophage-like lining cells

HA inhibits proliferation of FLS

Decorin

Modulates MMP-1 gene expression of rabbit FLS when present on the substrate with Vn or Fn fragment

Perlecan

Involved in adhesion and growth of FLS

Collagen type I

FLS adhering to collagen type I show higher proliferative ability in response to PDGF. Adhesion to

collagen type I through integrin β 1 downregulates the collagenase expression in human FLS

Collagen type IV

Synthesized by FLS

RA-FLS bind more strongly to collagen type IV than normal FLS

monoclonal antibodies to integrin β 1 block adhesion

Degraded by MMP-2, MT-MMP

Degraded by matrilysin