Prostaglandin E(2) inhibits collagen expression and proliferation in patient-derived normal lung fibroblasts via E prostanoid 2 receptor and cAMP signaling.
Uncontrolled fibroblast activation is one of the hallmarks of fibrotic lung disease. Prostaglandin E(2) (PGE(2)) has been shown to inhibit fibroblast migration, proliferation, collagen deposition, and myofibroblast differentiation in the lung. Understanding the mechanisms for these effects may provide insight into the pathogenesis of fibrotic lung disease. Previous work has focused on commercially available fibroblast cell lines derived from tissue whose precise origin and histopathology are often unknown. Here, we sought to define the mechanism of PGE(2) inhibition in patient-derived fibroblasts from peripheral lung verified to be histologically normal. Fibroblasts were grown from explants of resected lung, and proliferation and collagen I expression was determined following treatment with PGE(2) or modulators of its receptors and downstream signaling components. PGE(2) inhibited fibroblast proliferation by 33% and collagen I expression by 62%. PGE(2) resulted in a 15-fold increase in intracellular cAMP; other cAMP-elevating agents inhibited collagen I in a manner similar to PGE(2). These effects were reproduced by butaprost, a PGE(2) analog selective for the cAMP-coupled E prostanoid (EP) 2 receptor, but not by selective EP3 or EP4 agonists. Fibroblasts expressed both major cAMP effectors, protein kinase A (PKA) and exchange protein activated by cAMP-1 (Epac-1), but only a selective PKA agonist was able to appreciably inhibit collagen I expression. Treatment with okadaic acid, a phosphatase inhibitor, potentiated the effects of PGE(2). Our data indicate that PGE(2) inhibits fibroblast activation in primary lung fibroblasts via binding of EP2 receptor and production of cAMP; inhibition of collagen I proceeds via activation of PKA.
Huang
Steven
S
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
Wettlaufer
Scott H
SH
Hogaboam
Cory
C
Aronoff
David M
DM
Peters-Golden
Marc
M
D049109:Cell Proliferation / Q000187:drug effects; D024042:Collagen Type I / Q000096:biosynthesis / Q000378:metabolism*; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000378:metabolism* / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D020662:Guanine Nucleotide Exchange Factors / Q000819:agonists; D006801:Humans; D008168:Lung / Q000166:cytology* / Q000187:drug effects; D019319:Okadaic Acid / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D011458:Prostaglandins E / Q000494:pharmacology*; D021122:Protein Subunits / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018078:Receptors, Prostaglandin E / Q000235:genetics / Q000378:metabolism*; D058307:Receptors, Prostaglandin E, EP2 Subtype; D015398:Signal Transduction / Q000187:drug effects*
C473217:8-(4-chloro-phenylthio)-2'-O-methyladenosine-3'-5'-cyclic monophosphate; D024042:Collagen Type I; D020662:Guanine Nucleotide Exchange Factors; C545644:PTGER2 protein, human; D011458:Prostaglandins E; D021122:Protein Subunits; C116122:RAPGEF3 protein, human; D012333:RNA, Messenger; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; D019319:Okadaic Acid; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases