Pentoxifylline and its active metabolite lisofylline attenuate transforming growth factor β1-induced asthmatic bronchial fibroblast-to-myofibroblast transition

Abstract

Bronchial asthma is characterized by persistent airway inflammation and airway wall remodeling. Among many different cells and growth factors triggering changes in bronchi structure, transforming growth factor β1-induced fibroblast to myofibroblast transition is believed to be very important. The aim of this study was to evaluate whether theophylline (used in asthma therapy) and two other methylxanthines (pentoxifylline and its active metabolite lisofylline), may affect transforming growth factor β1-induced fibroblast to myofibroblast transition in bronchial fibroblasts derived from asthmatic patients. We show here for the first time that selected methylxanthines effectively reduce transforming growth factor β1-induced myofibroblast formation in asthmatic bronchial fibroblast populations. PTX was found to be the most effective methylxanthine. The number of differentiated myofibroblasts after PTX, LSF and THEO administration was reduced at least twofold. Studies on the use of methylxanthines opens a new perspective in the development of novel strategies in asthma therapy through their two-pronged, anti-inflammatory and anti-fibrotic action. In the future they can be considered as promising anti-fibrotic drugs.

Fenofibrate Reduces the Asthma-Related Fibroblast-To-Myofibroblast Transition by TGF-Β/Smad2/3 Signaling Attenuation and Connexin 43-Dependent Phenotype Destabilization

“…The majority of drugs currently available for bronchial asthma therapy do not significantly inhibit the fibrotic changes in the bronchial wall [ 29 ]. Only a few anti-inflammatory drugs used in the treatment of asthma (e.g., β 2 -adrenergic receptor agonists, glucocorticosteroids [ 29 ], methylxanthines [ 30 ], and statins [ 17 ]) were suggested to indirectly affect bronchial subepithelial fibrosis. However, numerous studies demonstrated anti-fibrotic effects of fenofibrate in models of hepatic [ 26 , 31 ], cardiac [ 32 , 33 , 34 ], renal [ 35 ], and lung [ 22 ] fibrosis, whereas the impact of fenofibrate on subepithelial fibrosis during asthma progression remains unaddressed.…”

“…Fenofibrate was already shown to inhibit the TGF-β 1 /Smad signaling axis in fibrotic processes in a model of diabetic nephropathy [ 43 ]. Previously, we showed the impact of statins [ 17 ] and methylxanthines [ 30 ] on the attenuation of the TGF-β 1 /Smad2 signaling axis in HBFs derived from asthma patients. Therefore, a fenofibrate-induced impairment of this signaling pathway may be associated with fenofibrate interference with cholesterol metabolism [ 31 , 44 , 45 , 46 ].…”

“…5% of cells. HBFs were cultured in a complete medium (Dulbecco’s modified Eagle medium; Sigma-Aldrich, St. Louis, MO, USA), supplemented with 10% fetal bovine serum (FBS; Gibco TM , Thermo Fisher Scientific, Waltham, MA, USA), and a penicillin/streptomycin cocktail (P4333; Sigma-Aldrich, St. Louis, MO, USA) as described previously [ 23 , 30 ]. For each experiment (unless otherwise noted), the cells were seeded at a density of 5000 cells/cm 2 and cultured in complete medium for 24 h, followed by 24 h in serum-free medium containing 0.1% bovine serum albumin (BSA; Sigma-Aldrich, St. Louis, MO, USA).…”

“…For the proliferation tests, the cells were cultured in complete medium for 24 h and then in a serum-free medium with or without fenofibrate (0–50 µM) for varied times, from one to seven days. Then, the cells were fixed with 3.7% formaldehyde/PBS, and the crystal violet assay was performed [ 30 ]. The results are shown as absorbance values (540 nm).…”

“…HBF cultures were lysed as described previously [ 23 , 30 ], and the protein content in the supernatant was determined using the Bradford method. Protein samples (30 µg/lane) were electrophoresed on 10% SDS-polyacrylamide gels and transferred to polyvinylidene difluoride (PVDF) membranes (Bio Rad, Hercules, CA, USA) as described previously [ 23 , 57 ].…”