Rapamycin inhibits transforming growth factor β1-induced fibrogenesis in primary human lung fibroblasts.
OBJECTIVE
The present study was designed to determine whether rapamycin could inhibit transforming growth factor β1 (TGF-β1)-induced fibrogenesis in primary lung fibroblasts, and whether the effect of inhibition would occur through the mammalian target of rapamycin (mTOR) and its downstream p70S6K pathway.


METHODS
Primary normal human lung fibroblasts were obtained from histological normal lung tissue of 3 patients with primary spontaneous pneumothorax. Growth arrested, synchronized fibroblasts were treated with TGF-β1 (10 ng/mL) and different concentrations of rapamycin (0.01, 0.1, 1, 10 ng/mL) for 24 h. We assessed m-TOR, p-mTOR, S6K1, p-S6K1 by Western blot analysis, detected type III collagen and fibronectin secreting by ELISA assay, and determined type III collagen and fibronectin mRNA levels by real-time PCR assay.


RESULTS
Rapamycin significantly reduced TGF-β1-induced type III collagen and fibronectin levels, as well as type III collagen and fibronectin mRNA levels. Furthermore, we also found that TGF-β1-induced mTOR and p70S6K phosphorylation were significantly down-regulated by rapamycin. The mTOR/p70S6K pathway was activated through the TGF-β1-mediated fibrogenic response in primary human lung fibroblasts.


CONCLUSIONS
These results indicate that rapamycin effectively suppresses TGF-β1-induced type III collagen and fibronectin levels in primary human lung fibroblasts partly through the mTOR/p70S6K pathway. Rapamycin has a potential value in the treatment of pulmonary fibrosis.
Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, 8 Gongren Tiyuchang South Road, Beijing 100020, China.
Yu
Y
Gao
Xuefeng
X
Xu
Ke
K
Ding
Yan
Y
Liang
Dianhua
D
Jiang
Huaping
H
Dai
D002478:Cells, Cultured; D024061:Collagen Type III / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000166:cytology / Q000187:drug effects; D011658:Pulmonary Fibrosis / Q000188:drug therapy; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology; D053773:Transforming Growth Factor beta1 / Q000037:antagonists & inhibitors* / Q000502:physiology
D024061:Collagen Type III; D005353:Fibronectins; D053773:Transforming Growth Factor beta1; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus