Transforming growth factor beta2-induced myofibroblastic differentiation of human retinal pigment epithelial cells: regulation by extracellular matrix proteins and hepatocyte growth factor.
Retinal pigment epithelial (RPE) cells possess the potential to transdifferentiate into myofibroblasts after stimulation with transforming growth factor beta (TGFbeta) and are implicated in the pathogenesis of proliferative vitreoretinopathy. In this study we evaluated how TGFbeta2 and various extracellular matrix (ECM) proteins modulate the transdifferentiation of human fetal retinal pigment epithelial cells (RPE) cells into myofibroblast-like cells. Furthermore, we investigated whether hepatocyte growth factor (HGF) can suppress this transdifferentiation. RPE cells were cultured on ECM coated or uncoated surfaces in the presence or absence of TGFbeta2. HGF was added to certain cultures only once or on a daily basis during the treatment. Transdifferentiation of RPE cells into myofibroblasts was assessed by the quantitation of alpha-smooth muscle actin (alpha-SMA) using immunocytochemistry, flow cytometry, real-time PCR and Western blotting. TGFbeta2 induced a significant increase of alpha-SMA expression in a dose-dependent manner. Compared with growth on uncoated surfaces, RPE cultured on fibronectin (FN)-coated surfaces and stimulated with TGFbeta2 showed a significantly higher alpha-SMA expression than untreated cells. This upregulation of alpha-SMA could be markedly reduced by daily treatment with HGF; however, a single HGF administration did not significantly reduce alpha-SMA. These findings are important for further understanding the interaction of cytokines, RPE cells and their environment in mesenchymal transformation as well as its possible modulation. Continuous or long-term treatment with HGF should be further investigated for its potential to prevent mesenchymal transdifferentiation of RPE cells, and ultimately, PVR in vivo.
Doheny Eye Institute, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Los Angeles, CA 90033, USA. gamulescu@eye-regensburg.de
Maria-Andreea
MA
Gamulescu
Youxin
Y
Chen
Shikun
S
He
Christine
C
Spee
Manlin
M
Jin
Stephen J
SJ
Ryan
David R
DR
Hinton
D000199:Actins / Q000032:analysis; D000906:Antibodies / Q000276:immunology; D015153:Blotting, Western / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D003470:Culture Media; D004305:Dose-Response Relationship, Drug; D016326:Extracellular Matrix Proteins / Q000494:pharmacology*; D005347:Fibroblasts / Q000502:physiology*; D005353:Fibronectins / Q000494:pharmacology / Q000502:physiology; D005434:Flow Cytometry / Q000379:methods; D017228:Hepatocyte Growth Factor / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007166:Immunosuppressive Agents / Q000276:immunology / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000166:cytology* / Q000187:drug effects / Q000196:embryology; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000276:immunology / Q000494:pharmacology / Q000502:physiology*; D053781:Transforming Growth Factor beta2; D015854:Up-Regulation / Q000502:physiology
D000199:Actins; D000906:Antibodies; D003470:Culture Media; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D007166:Immunosuppressive Agents; D011994:Recombinant Proteins; C509041:TGFB2 protein, human; D016212:Transforming Growth Factor beta; D053781:Transforming Growth Factor beta2; D017228:Hepatocyte Growth Factor