Transforming growth factor-beta receptor type 1 (TGFbetaRI) kinase activity but not p38 activation is required for TGFbetaRI-induced myofibroblast differentiation and profibrotic gene expression.
Transforming growth factor-beta (TGFbeta) is a major mediator of normal wound healing and of pathological conditions involving fibrosis, such as idiopathic pulmonary fibrosis. TGFbeta also stimulates the differentiation of myofibroblasts, a hallmark of fibrotic diseases. In this study, we examined the underlying processes of TGFbetaRI kinase activity in myofibroblast conversion of human lung fibroblasts using specific inhibitors of TGFbetaRI (SD-208) and p38 mitogen-activated kinase (SD-282). We demonstrated that SD-208, but not SD-282, inhibited TGFbeta-induced SMAD signaling, myofibroblast transformation, and collagen gel contraction. Furthermore, we extended our findings to a rat bleomycin-induced lung fibrosis model, demonstrating a significant decrease in the number of myofibroblasts at fibroblastic foci in animals treated with SD-208 but not those treated with SD-282. SD-208 also reduced collagen deposition in this in vivo model. Microarray analysis of human lung fibroblasts identified molecular fingerprints of these processes and showed that SD-208 had global effects on reversing TGFbeta-induced genes involved in fibrosis, inflammation, cell proliferation, cytoskeletal organization, and apoptosis. These studies also revealed that although the p38 pathway may not be needed for appearance or disappearance of the myofibroblast, it can mediate a subset of inflammatory and fibrogenic events of the myofibroblast during the process of tissue repair and fibrosis. Our findings suggest that inhibitors such as SD-208 may be therapeutically useful in human interstitial lung diseases and pulmonary fibrosis.
Kapoun
Ann M
AM
Scios Inc., Fremont, CA 94555, USA. ann_kapoun@yahoo.com
Gaspar
Nicholas J
NJ
Wang
Ying
Y
Damm
Debby
D
Liu
Yu-Wang
YW
O'young
Gilbert
G
Quon
Diana
D
Lam
Andrew
A
Munson
Kimberly
K
Tran
Thomas-Toan
TT
Ma
Jing Ying
JY
Murphy
Alison
A
Dugar
Sundeep
S
Chakravarty
Sarvajit
S
Protter
Andrew A
AA
Wen
Fu-Qiang
FQ
Liu
Xiangde
X
Rennard
Stephen I
SI
Higgins
Linda Slanec
LS
D030201:Activin Receptors, Type I / Q000037:antagonists & inhibitors / Q000502:physiology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D055513:Connective Tissue Growth Factor; D003599:Cytoskeleton / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D005786:Gene Expression Regulation; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics; D007249:Inflammation / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D020935:MAP Kinase Signaling System; D020411:Oligonucleotide Array Sequence Analysis; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011621:Pteridines / Q000494:pharmacology; D011658:Pulmonary Fibrosis / Q000188:drug therapy / Q000209:etiology*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D051785:Smad Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014945:Wound Healing; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
C526317:CCN2 protein, human; C526316:CCN2 protein, rat; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011621:Pteridines; D018125:Receptors, Transforming Growth Factor beta; C511004:SD-208; D051785:Smad Proteins; D016212:Transforming Growth Factor beta; D055513:Connective Tissue Growth Factor; D003094:Collagen; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625843:Tgfbr1 protein, rat