The TGF-β1 Signaling Pathway as an Attractive Target in the Fibrosis Pathogenesis of Sjögren’s Syndrome

Figure 1

(a) Immunohistochemical localization of TGF-β1, pSMAD2/3, and SMAD4 in healthy (A, C, E) and pSS (B, D, F) SG tissues. The analysis revealed TGF-β1 expression in the cytoplasm of most interstitial infiltrating mononuclear cells, fibroblasts, and acinar and ductal cells of all the SG specimens analyzed. A strong positivity for TGF-β1 was detected in acinar and ductal cells of pSS sections (B), and the intensity of labeling was strongly reduced in healthy salivary tissue (A); high levels of pSMAD2/3 were detected in pSS specimens, and expression analysis showed that the number of positive cells for pSMAD2/3 was higher in pSS samples (D) when compared with normal tissue (C). A prominent immunostaining for SMAD4 was observed in acinar and ductal cells of pSS biopsies (F) compared with healthy subjects (E). Brown staining shows positive immunoreaction; blue staining shows nuclei. (A, B, C, D, E, F) original magnification, ×20; . All images were scanned and analyzed with Aperio ImageScope instrument. (b) panels G, H, and I represent immunohistochemistry signal quantification of TGF-β1, pSMAD2/3, and SMAD4 positivity, respectively, performed by the Aperio ImageScope Software on healthy and pSS SG sections. Absorbance measurements performed by Aperio confirmed the microscopy observation and showed that staining for TGF-β1, pSMAD2/3, and SMAD4 were significantly increased in pSS glands than in the control glands ().