A secreted collagen- and fibronectin-binding streptococcal protein modulates cell-mediated collagen gel contraction and interstitial fluid pressure.
Fibroblast-mediated collagen gel contraction depends on collagen-binding beta1 integrins. Perturbation of these integrins reveals an alternative contraction process that is integrin alphaVbeta3-dependent and platelet-derived growth factor (PDGF) BB-stimulated. Connective tissue cells actively control interstitial fluid pressure (IFP), and inflammation-induced lowering of IFP provides a driving force for edema formation. PDGF-BB normalizes a lowered IFP by an alphaVbeta3-dependent process. A potential modulation of IFP by extracellular matrix-binding bacterial proteins has previously not been addressed. The fibronectin (FN)-binding protein FNE is specifically secreted by the highly virulent Streptococcus equi subspecies equi. FNE bound FN and native collagen type I with K(d) values of approximately 20 and approximately 50 nm determined by solid-phase binding assays. Rotary shadowing revealed a single FNE binding site located at on average 122 nm from the C terminus of procollagen type I. FNE induced alphaVbeta3-mediated contraction by C2C12 cells in a concentration-dependent manner having a maximal effect at approximately 100 nm. This activity of FNE required cellular FN, and FNE acted synergistically to added plasma FN or PDGF-BB. FNE enhanced binding of soluble FN to immobilized collagen, and conversely the binding of collagen to immobilized FN. Marked bell-shaped concentration dependences for these interactions suggest that FNE forms a bridge between FN and collagen. Finally, FNE normalized dermal IFP lowered by anaphylaxis. Our data suggest that secreted FNE normalized lowering of IFP by stimulating connective tissue cell contraction.
Lidén
Åsa
Å
Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden; Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway.
van Wieringen
Tijs
T
Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden.
Lannergård
Jonas
J
Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden.
Kassner
Anja
A
Department of Experimental Medical Sciences, BMC, B-12, University of Lund, SE-221 84 Lund, Sweden.
Heinegård
Dick
D
Department of Experimental Medical Sciences, BMC, B-12, University of Lund, SE-221 84 Lund, Sweden.
Reed
Rolf K
RK
Department of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway.
Guss
Bengt
B
Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden.
Rubin
Kristofer
K
Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-751 23 Uppsala, Sweden. Electronic address: Kristofer.Rubin@imbim.uu.se.
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D000707:Anaphylaxis; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D002460:Cell Line; D003094:Collagen / Q000378:metabolism*; D024042:Collagen Type I / Q000378:metabolism; D020405:Dermis / Q000166:cytology; D045604:Extracellular Fluid / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D005782:Gels; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D032446:Myoblasts / Q000166:cytology*; D011312:Pressure; D011485:Protein Binding; D012995:Solubility; D013291:Streptococcus / Q000378:metabolism*
D018829:Adhesins, Bacterial; D024042:Collagen Type I; D005353:Fibronectins; D005782:Gels; D039302:Integrin alphaVbeta3; C078635:fibronectin-binding proteins, bacterial; D003094:Collagen