The mTORC1/4E-BP1 axis represents a critical signaling node during fibrogenesis

Nat Commun. 2019 Jan 2;10(1):6. doi: 10.1038/s41467-018-07858-8.

Abstract

Myofibroblasts are the key effector cells responsible for excessive extracellular matrix deposition in multiple fibrotic conditions, including idiopathic pulmonary fibrosis (IPF). The PI3K/Akt/mTOR axis has been implicated in fibrosis, with pan-PI3K/mTOR inhibition currently under clinical evaluation in IPF. Here we demonstrate that rapamycin-insensitive mTORC1 signaling via 4E-BP1 is a critical pathway for TGF-β1 stimulated collagen synthesis in human lung fibroblasts, whereas canonical PI3K/Akt signaling is not required. The importance of mTORC1 signaling was confirmed by CRISPR-Cas9 gene editing in normal and IPF fibroblasts, as well as in lung cancer-associated fibroblasts, dermal fibroblasts and hepatic stellate cells. The inhibitory effect of ATP-competitive mTOR inhibition extended to other matrisome proteins implicated in the development of fibrosis and human disease relevance was demonstrated in live precision-cut IPF lung slices. Our data demonstrate that the mTORC1/4E-BP1 axis represents a critical signaling node during fibrogenesis with potential implications for the development of novel anti-fibrotic strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Cell Cycle Proteins
  • Cell Line
  • Collagen / biosynthesis*
  • Fibroblasts / metabolism*
  • Humans
  • Idiopathic Pulmonary Fibrosis / etiology
  • Mechanistic Target of Rapamycin Complex 1 / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoproteins / metabolism*
  • Signal Transduction
  • Sirolimus
  • TOR Serine-Threonine Kinases / metabolism
  • Transforming Growth Factor beta1 / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Cell Cycle Proteins
  • EIF4EBP1 protein, human
  • Phosphoproteins
  • TGFB1 protein, human
  • Transforming Growth Factor beta1
  • Collagen
  • MTOR protein, human
  • Mechanistic Target of Rapamycin Complex 1
  • TOR Serine-Threonine Kinases
  • Sirolimus