Signaling pathway by which TGF-beta1 increases expression of latent TGF-beta binding protein-2 at the transcriptional level

Connect Tissue Res. 1998;37(3-4):263-76. doi: 10.3109/03008209809002444.

Abstract

The cytokine transforming growth factor-beta has multiple effects on a wide variety of cell types. These effects include modulation of growth and regulation of gene transcription. In the present work, we demonstrate that TGF-beta1 increases transcription of the latent transforming growth factor-beta binding protein-2 ( LTBP-2) gene in cultured human fetal lung fibroblasts leading to a significant increase in LTBP-2 mRNA steady state level. The stability of LTBP-2 mRNA was not appreciably altered. A corresponding increase in production of LTBP-2 protein accompanied the increase in mRNA. Through the use of specific inhibitors, we demonstrate that a member of the Ras super family and a protein kinase C, probably of the atypical (non-diacylglycerol, non-Ca++ dependent) class are likely to be components in the signaling pathway. However, phospholipases, G proteins and extracellular-signal regulated kinases do not appear to be involved. These results combined with previous findings on elastin regulation by TGF-beta1 (Kucich et al. (1997). Am. J. Respir. Cell Mol. Biol., 17: 10-16) demonstrate that TGF-beta1 can coordinately increase the steady state levels of mRNAs encoding components of the elastic fiber, but through diverse mechanisms. In contrast to LTBP-2, increased elastin expression is achieved by message stabilization. Furthermore, the TGF-beta1 signaling pathways differ and while the pathway leading to increased LTBP-2 transcription shares components with those modulating transcription of other genes, it is unlikely to be precisely congruent with any other previously described one.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing*
  • Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors
  • Carrier Proteins / genetics*
  • Cells, Cultured
  • Enzyme Inhibitors / pharmacology
  • Flavonoids / pharmacology
  • Gene Expression Regulation / drug effects*
  • Humans
  • Latent TGF-beta Binding Proteins
  • Naphthalenes / pharmacology
  • Protein Kinase C / antagonists & inhibitors
  • RNA, Messenger
  • Signal Transduction*
  • Transcription, Genetic / drug effects
  • Transforming Growth Factor beta / metabolism*
  • Transforming Growth Factor beta / pharmacology

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Enzyme Inhibitors
  • Flavonoids
  • LTBP2 protein, human
  • Latent TGF-beta Binding Proteins
  • Naphthalenes
  • RNA, Messenger
  • Transforming Growth Factor beta
  • calphostin complex
  • Protein Kinase C
  • Calcium-Calmodulin-Dependent Protein Kinases
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one