A phosphodiesterase 4 inhibitor, roflumilast N-oxide, inhibits human lung fibroblast functions in vitro.
The PDE4 inhibitor roflumilast mitigates bleomycin-induced lung fibrotic remodeling in rodents. In the current study it was explored whether roflumilast N-oxide, the active metabolite of roflumilast influences functions of cultured lung fibroblasts. Cells of the human foetal lung fibroblast strain GM06114 were stimulated with TNF-alpha (5 ng ml(-1)) and cell surface ICAM-1 and eotaxin release were assessed. [methyl-(3)H] thymidine incorporation was measured following stimulation with bFGF (10 ng ml(-1)). alpha-Smooth muscle actin (protein), CTGF (mRNA) and fibronectin (mRNA) were determined secondary to TGFbeta1 (1 ng ml(-1)). In the presence of PGE(2) (1 nM), roflumilast N-oxide reduced TNF-alpha-induced ICAM-1 and eotaxin by about 70% and >90% with half-maximum inhibition at 0.9 nM and 0.5 nM, respectively. Roflumilast N-oxide also attenuated [methyl-(3)H] thymidine incorporation secondary to bFGF by about 75% with half-maximum inhibition at 0.7 nM when cells were co-incubated with IL-1beta (10 pg ml(-1)). In the presence of this cytokine roflumilast N-oxide (1 microM) diminished TGFbeta1-induced expression of alpha-smooth muscle actin and transcripts of CTGF and fibronectin. In addition, IL-1beta up-regulated PDE4 activity in the lung fibroblasts. Taken together, these findings indicate that roflumilast N-oxide directly targets human lung fibroblasts, which may at least partially explain the efficacy of roflumilast to mitigate a pulmonary fibrotic response in vivo.
Pulmonary Disease Unit, G Gaslini Institute, Largo G Gaslini 5, 16147 Genoa, Italy. federicasabatini@ospedale-gaslini.ge.it
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Sabatini
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Petecchia
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Boero
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Silvestri
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Klar
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Tenor
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R
Beume
A
A
Hatzelmann
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GA
Rossi
D000199:Actins / Q000378:metabolism; D000631:Aminopyridines / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology*; D002478:Cells, Cultured; D055513:Connective Tissue Growth Factor / Q000378:metabolism; D003521:Cyclopropanes / Q000494:pharmacology; D016503:Drug Delivery Systems; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D005353:Fibronectins / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009130:Muscle, Smooth / Q000378:metabolism; D058988:Phosphodiesterase 4 Inhibitors; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000378:metabolism
D000199:Actins; D000631:Aminopyridines; D001549:Benzamides; C526317:CCN2 protein, human; D003521:Cyclopropanes; D005353:Fibronectins; D058988:Phosphodiesterase 4 Inhibitors; D010726:Phosphodiesterase Inhibitors; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D055513:Connective Tissue Growth Factor; C517734:roflumilast N-oxide