Streptococcus mutans antigen I/II binds to α5β1 integrins via its A-domain and increases β1 integrins expression on periodontal ligament fibroblast cells.
The cell wall anchored protein I/II of Streptococcus mutans plays a significant role in colonizing the dental structures and induces the synthesis of proinflammatory cytokines after binding to α5β1 integrins of host cells. Whilst the signalling pathways triggered by bound protein I/II and leading to the release of proinflammatory cytokines has been extensively studied, the molecular mechanisms of binding of protein I/II to this host cell factor remain more elusive. Using a panel of purified recombinant polypeptides corresponding to defined domains of the streptococcal protein I/II, we aimed to better characterize protein I/II-α5β1 integrins interaction. Our results show that the A region plays a major role in binding of protein I/II to α5β1 integrin. Using specific inhibitors, we demonstrated that this interaction requires β subunits of the integrin and that the glycosylated residues of the integrin interact with the V-region of the protein I/IIf. Periodontal fibroblasts (PDL-Fb) express β1-integrins on their cell membrane. Stimulation with protein I/II increases the expression of β1-integrins. These data suggest a modulatory effect of the streptococcal protein I/II on expression of integrins by PDL-Fb. This might have important implication for understanding the role of PDL-Fb cells in periradicular inflammation.
Engels-Deutsch
Marc
M
Inserm, U392, Université Louis Pasteur de Strasbourg, F-67400 Illkirch, France. marc.engels@sfr.fr
Rizk
Samer
S
Haïkel
Youssef
Y
D018829:Adhesins, Bacterial / Q000378:metabolism*; D000942:Antigens, Bacterial / Q000378:metabolism; D001422:Bacterial Adhesion / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism / Q000382:microbiology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D039081:Integrin alpha5beta1 / Q000378:metabolism*; D019012:Integrin beta1 / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D010513:Periodontal Ligament / Q000166:cytology / Q000382:microbiology*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins; D013295:Streptococcus mutans / Q000276:immunology*
D018829:Adhesins, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018836:Inflammation Mediators; D039081:Integrin alpha5beta1; D019012:Integrin beta1; D008565:Membrane Proteins; D011994:Recombinant Proteins; C508943:protein I-II, Streptococcus mutans