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. Author manuscript; available in PMC: 2010 Feb 1.
Published in final edited form as: Arthritis Rheum. 2009 Feb;60(2):584–591. doi: 10.1002/art.24221

Figure 2. Imatinib reduces PDGFRβ and Abl activation in SSc skin and function in SSc fibroblasts.

Figure 2

(A–D) Immunohistochemical staining of serial skin biopsy samples obtained pretreatment (A,C) and one month following the initiation of imatinib treatment (B,D) with anti-phospho-PDGFRβ (A,B) and anti-phospho-Abl (C,D) antibodies. Boxed areas of upper panels (200× magnification), are presented at higher magnification in their corresponding lower panels (600×). Results are representative of those obtained from multiple sections from two independent patients. Phospho-PDGFRβ was observed in interstitial fibroblasts as well as perivascular spindle-like cells and some cells resembling mast cells. Phospho-Abl was observed in endothelial cells in small vessels and in scattered dermal fibroblasts. (E) Stimulation of a SSc fibroblast line with PDGF (10 ng/ml), TGF-β (0.5 ng/ml), PDGF + TGF-β, or PDGF + TGF-β+ imatinib (1 µM). Proliferation was quantitated after 48 hours by 3H-thymidine incorporation (Y axis). Results are representative of experiments performed on two independent SSc fibroblast lines, and similar results were obtained with normal fibroblast lines.