TGFbeta1 induces epithelial-mesenchymal transition, but not myofibroblast transdifferentiation of human kidney tubular epithelial cells in primary culture.
The origin and fate of renal interstitial myofibroblasts (MFs), the effector cells of renal fibrosis, are still debated. Experimental evidence suggests that renal MFs derive from tubular epithelial cells throughout the epithelial-mesenchymal transition (EMT) process. Primary human tubular epithelial cells (HUTECs) were cultured for 4 and 6 days on plastic or type I collagen-coated plates with 1, 5, 10 and 50 ng/ml of transforming growth factor beta1 (TGFbeta1). The EMT process was monitored by morphology and immunophenotyping for alphaSMA, cytokeratin 8-18, E-cadherin, vimentin and collagen III. Quantitative comparative RT/PCR and real-time PCR were used to evaluate the expression of collagen III and IV, fibronectin, tenascin, MMP-2, CTGF, E-cadherin and cadherin 11 genes, as well as those of the Smad signalling pathway. TGFbeta1 was found capable of reactivating the mesenchymal programme switched off during tubulogenesis, but it induced no de novo expression of alphaSMA gene or myofibroblast phenotype. We demonstrate that the EMT process is conditioned by the extracellular matrix and characterized by TGFbeta1-driven Smad3 downregulation. Our study results suggest that TGFbeta1 could function as a classic embryonal inducer, initiating a cascade of de-differentiating events that might be further controlled by other factors in the cellular environment.
Forino
Monica
M
Laboratory of Histomorphology and Molecular Biology of the Kidney, Division of Nephrology, Department of Medical and Surgical Sciences, University of Padua, Padova, Italy.
Torregrossa
Rossella
R
Ceol
Monica
M
Murer
Luisa
L
Della Vella
Manuela
M
Del Prete
Dorella
D
D'Angelo
Angela
A
Anglani
Franca
F
D000199:Actins / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis; D015820:Cadherins / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D024061:Collagen Type III / Q000378:metabolism; D024141:Collagen Type IV / Q000378:metabolism; D055513:Connective Tissue Growth Factor; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004627:Embryonic Induction; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D007633:Keratins / Q000378:metabolism; D007684:Kidney Tubules / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D008648:Mesoderm / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051900:Smad3 Protein / Q000378:metabolism; D019063:Tenascin / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
D000199:Actins; D015415:Biomarkers; C526317:CCN2 protein, human; D015820:Cadherins; D024061:Collagen Type III; D024141:Collagen Type IV; D005353:Fibronectins; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D051900:Smad3 Protein; C508960:TGFB1 protein, human; D019063:Tenascin; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D055513:Connective Tissue Growth Factor; D007633:Keratins; D020778:Matrix Metalloproteinase 2