Pirfenidone inhibits TGF-β1-induced over-expression of collagen type I and heat shock protein 47 in A549 cells.
BACKGROUND
Pirfenidone is a novel anti-fibrotic and anti-inflammatory agent that inhibits the progression of fibrosis in animal models and in patients with idiopathic pulmonary fibrosis (IPF). We previously showed that pirfenidone inhibits the over-expression of collagen type I and of heat shock protein (HSP) 47, a collagen-specific molecular chaperone, in human lung fibroblasts stimulated with transforming growth factor (TGF)-β1 in vitro. The increased numbers of HSP47-positive type II pneumocytes as well as fibroblasts were also diminished by pirfenidone in an animal model of pulmonary fibrosis induced by bleomycin. The present study evaluates the effects of pirfenidone on collagen type I and HSP47 expression in the human alveolar epithelial cell line, A549 cells in vitro.


METHODS
The expression of collagen type I, HSP47 and E-cadherin mRNAs in A549 cells stimulated with TGF-β1 was evaluated by Northern blotting or real-time PCR. The expression of collagen type I, HSP47 and fibronectin proteins was assessed by immunocytochemical staining.


RESULTS
TGF-β1 stimulated collagen type I and HSP47 mRNA and protein expression in A549 cells, and pirfenidone significantly inhibited this process. Pirfenidone also inhibited over-expression of the fibroblast phenotypic marker fibronectin in A549 cells induced by TGF-β1.


CONCLUSIONS
We concluded that the anti-fibrotic effects of pirfenidone might be mediated not only through the direct inhibition of collagen type I expression but also through the inhibition of HSP47 expression in alveolar epithelial cells, which results in reduced collagen synthesis in lung fibrosis. Furthermore, pirfenidone might partially inhibit the epithelial-mesenchymal transition.
Second Department of Internal Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
Keiko
K
Hisatomi
Hiroshi
H
Mukae
Noriho
N
Sakamoto
Yuji
Y
Ishimatsu
Tomoyuki
T
Kakugawa
Shintaro
S
Hara
Hanako
H
Fujita
Seiko
S
Nakamichi
Hisashi
H
Oku
Yoshishige
Y
Urata
Hiroshi
H
Kubota
Kazuhiro
K
Nagata
Shigeru
S
Kohno
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D024042:Collagen Type I / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005353:Fibronectins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D050958:HSP47 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000473:pathology; D011658:Pulmonary Fibrosis / Q000378:metabolism / Q000473:pathology; D011728:Pyridones / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D015820:Cadherins; D024042:Collagen Type I; D005353:Fibronectins; D050958:HSP47 Heat-Shock Proteins; D011728:Pyridones; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; C093844:pirfenidone