Cell-specific regulation of α1(III) and α2(V) collagen by TGF-β1 in tubulointerstitial cell models

Roberta Bertelli, Federico Valenti, Roberta Oleggini, Gianluca Caridi, Paola Altieri, Domenico A. Coviello, Gerardo Botti, Roberto Ravazzolo, Gian Marco Ghiggeri

Research output: Contribution to journalArticle

Abstract

Background. TGF-β1 modulates the cellular expression of extracellular matrix (ECM) in several renal cell systems in vitro and is considered a determinant of ECM accumulation in tubulointerstitial fibrosis. Methods. We evaluated the effects of TGF-β1 on collagen transcription, expression, and removal of the relevant collagens by rat tubuloepithelial cells (NRK 52E) and both rat and monkey interstitial fibroblasts (NRK 49F, CV1) in vitro. Results. TGF-β1 upregulated the expression of α1(III) collagen by fibroblasts (+ 300%) without affecting its removal. In parallel, a threefold increment of COL3A1 mRNA was found. Experiments of cell transfection employing CV1 fibroblasts as the unique suitable model, and chimaeric constructs of COL3A1 and COL5A2 promoters fused to the luciferase reporter gene, demonstrated a twofold stimulation of a large 1436 COL3A1 promoter construct and negligible effects on shorter fragments, suggesting the presence of a positive responsive element in a region of COL3A1 promoter between -1375 and -579. TGF-β1 did not influence COL5A2 mRNA and the relative promoter activity in renal fibroblasts. With NRK 52E cell line, TGF-β1 induced comparable increment of both α1(III) collagen expression (+ 300%) and COL3A1 mRNA (+ 300%) without affecting the COL3A1 promoter activity of any constructs. TGF-β1 also upregulated the expression of α2(V) collagen chain (+ 500%) and COL5A2 mRNA (+ 500%) with a stimulatory effect (+ 100%) on a 1177 bp fragment of COL5A2 promoter. In this case a relevant inhibitory effect of TGF-β1 on removal of α2(V) by supernatants of NRK 52E was also observed, indicating a double regulatory role of the cytokine on both transcription and removal of this component of ECM. Conclusion. Taken together these data indicate that TGF-β1 is a potent stimulator of α1(III) collagen expression by renal fibroblast cell lines in vitro, the basic mechanism being stimulation of COL3A1 transcription. With renal epithelial cell lines, TGF-β1 mainly upregulated the expression of type V collagen with the most relevant effect on stimulation of collagen transcription and inhibition of its removal. Tubular epithelial cells and renal fibroblasts should play distinct roles in renal fibrosis induced by TGF-β1 in vivo.

Original languageEnglish
Pages (from-to)573-579
Number of pages7
JournalNephrology Dialysis Transplantation
Volume13
Issue number3
DOIs
Publication statusPublished - Mar 1998

    Fingerprint

Keywords

  • Collagen
  • Extracellular matrix
  • Interstitial fibrosis
  • TGF-β

ASJC Scopus subject areas

  • Nephrology
  • Transplantation

Cite this