Transient transgene expression of decorin in the lung reduces the fibrotic response to bleomycin.
ABSTRACT Pulmonary fibrosis is a chronic progressive disease with no effective therapy. Transforming growth factor beta (TGF-beta) is thought to be a key profibrotic mediator and blocking its activity is therefore one of the targets of new treatment strategies for fibrosis. Decorin is an endogenous proteoglycan and one of the known inhibitors of TGF-beta. The short half-life of peptide-based therapeutics makes gene transfer a promising approach to achieve prolonged protein levels in the lung. Replication-deficient adenovirus was used to deliver decorin transgene (AdDec) to the airways by a single intranasal injection in a murine bleomycin model of lung fibrosis. The ability of vector-derived decorin to inhibit TGF-beta was examined in a bioassay and its effect on bleomycin-induced pulmonary fibrosis was determined by histomorphology and lung hydroxyproline. In vitro, supernatant from cells infected with AdDec abrogated the bioactivity of TGF-beta in a dose-dependent manner whereas control virus (AdDL70) had no effect. In vivo, treatment of bleomycin-injected mice with AdDec substantially reduced the fibrogenic response compared with control virus (hydroxyproline: bleomycin/AdDec, 1.96 microg/mg; bleomycin/AdDL70, 3.05 microg/mg; p = 0.0005). These results suggest that a single administration of AdDec was able to generate a local pulmonary environment that effectively blocked the fibrogenic response to bleomycin by inhibition of TGF-beta.
- SourceAvailable from: Javier Dotor[Show abstract] [Hide abstract]
ABSTRACT: Pulmonary fibrosis encompasses several respiratory diseases characterized by epithelial cell injury, inflammation and fibrosis. Transforming growth factor (TGF)-β1 is one of the main profibrogenic cytokines involved in the pathogenesis of lung fibrosis. It induces fibroblast differentiation into myofibroblasts, which produce high levels of collagen and concomitantly loss of lung elasticity and reduction of the respiratory function. In the present study, we have investigated the effects of P17 (a TGF-β inhibitor peptide) on IMR-90 lung fibroblast differentiation in vitro, as well as on the inhibition of the development of bleomycin-induced pulmonary fibrosis in mice. It was found that in IMR-90 cells, P17 inhibited TGF-β1-induced expression of connective tissue growth factor and α-smooth muscle actin. In vivo, treatment of mice with P17 2days after bleomycin administration decreased lung fibrosis, areas of myofibroblast-like cells and lymphocyte infiltrate. P17 also reduced mRNA expression of collagen type I, fibronectin and the fibronectin splice isoform EDA in the lung, and increased the expression of IFN-γ mRNA. Finally, therapeutic treatment with P17 in mice with already established fibrosis was able to significantly attenuate the progression of lung fibrosis. These results suggest that P17 may be useful in the treatment of pulmonary fibrosis.Cytokine 03/2011; 53(3):327-33. DOI:10.1016/j.cyto.2010.11.019 · 2.87 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Scar tissue at sites of traumatic injury in the adult central nervous system presents a combined physical and molecular impediment to axon regeneration. Of multiple known central nervous system scar associated axon growth inhibitors, semaphorin 3A has been shown to be strongly expressed by invading leptomeningeal fibroblasts. We have previously demonstrated that infusion of the small leucine-rich proteoglycan decorin results in major suppression of several growth inhibitory chondroitin sulphate proteoglycans and growth of adult sensory axons across acute spinal cord injuries. Furthermore, decorin treatment of leptomeningeal fibroblasts significantly increases their ability to support neurite growth of co-cultured adult dorsal root ganglion neurons. In the present study we show that decorin has the ability to suppress semaphorin 3A expression within adult rat cerebral cortex scar tissue and in primary leptomeningeal fibroblasts in vitro. Infusion of decorin core protein for eight days resulted in a significant reduction of semaphorin 3A messenger RNA expression within injury sites compared with saline-treated control animals. Both in situ hybridization and immunostaining confirmed that semaphorin 3A messenger RNA expression and protein levels are significantly reduced in decorin-treated animals. Similarly, decorin treatment decreased the expression of semaphorin 3A messenger RNA in cultured rat leptomeningeal fibroblasts compared with untreated cells. Mechanistic studies revealed that decorin-mediated suppression of semaphorin 3A critically depends on erythroblastic leukaemia viral oncogene homologue B4 and signal transducer and activator of transcription 3 function. Collectively, our studies show that in addition to suppressing the levels of inhibitory chondroitin sulphate proteoglycans, decorin has the ability to suppress semaphorin 3A in the injured central nervous system. Our findings provide further evidence for the use of decorin as a potential therapy for promoting axonal growth and repair in the injured adult mammalian brain and spinal cord.Brain 11/2010; 134(Pt 4):1140-55. DOI:10.1093/brain/awq304 · 10.23 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Different animal models of pulmonary fibrosis have been developed to investigate potential therapies for idiopathic pulmonary fibrosis (IPF). The most common is the bleomycin model in rodents (mouse, rat and hamster). Over the years, numerous agents have been shown to inhibit fibrosis in this model. However, to date none of these compounds are used in the clinical management of IPF and none has shown a comparable antifibrotic effect in humans. We performed a systematic review of publications on drug efficacy studies in the bleomycin model to evaluate the value of this model regarding transferability to clinical use. Between 1980 and 2006 we identified 240 experimental studies describing beneficial antifibrotic compounds in the bleomycin model. 222 of those used a preventive regimen (drug given < or =7 days after last bleomycin application), only 13 were therapeutic trials (>7 days after last bleomycin application). In 5 studies we did not find enough details about the timing of drug application to allow inter-study comparison. It is critical to distinguish between drugs interfering with the inflammatory and early fibrogenic response from those preventing progression of fibrosis, the latter likely much more meaningful for clinical application. All potential antifibrotic compounds should be evaluated in the phase of established fibrosis rather than in the early period of bleomycin-induced inflammation for assessment of its antifibrotic properties. Further care should be taken in extrapolation of drugs successfully tested in the bleomycin model due to partial reversibility of bleomycin-induced fibrosis over time. The use of alternative and more robust animal models, which better reflect human IPF, is warranted.The International Journal of Biochemistry & Cell Biology 12/2008; 40(3):362-82. DOI:10.1016/j.biocel.2007.08.011 · 4.24 Impact Factor