Method: HGF were stimulated with recombinant Gal-8. The production of Connective tissue growth factor (CTGF) and type I collagen (col-I) and activation of the Smad signaling pathway were evaluated by Western-blot. Fibronectin levels were evaluated through ELISA. Immunofluorescence was used to determine Smad activation.
Result: Recombinant Gal-8 was able to bind to TGF-beta receptor (TBR-II) in a cell lysate of HGF. Stimulation of HGF with Gal-8 increased the protein levels of col-I, CTGF and fibronectin. Gal-8 stimulated Smad 2/3 phosphorylation in the absence of exogenous TGF-beta. Gal-8-stimulated fibronectin levels were reduced in the presence of Smad-3 and Focal Adhesion Kinase (FAK) inhibitors.
Conclusion: Gal-8 stimulates the protein levels of several ECM molecules including CTGF, col-I and fibronectin . These effects are probably due to the interaction of Gal-8 with integrins and TBR-II. The present is the first study that describes a fibrotic role for Gal-8 in gingival tissues.