Nunzio Crimi

Idiopathic pulmonary fibrosis: a disease with similarities and links to cancer biology

Several clinical trials have recently targeted specific pathways implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). However, IPF remains plagued by a median survival of 3 yrs and emphasises the need for further research with new insights and perspectives. The prevailing pathogenic hypotheses assume that either an inflammatory process or an independent epithelial/fibroblastic disorder may propagate the disease process. Based on knowledge developed with considerable scientific evidence, we provide our perspectives with an alternative point of view that IPF be considered as a neoproliferative disorder of the lung. Genetic alterations, response to growth and inhibitory signals, resistance to apoptosis, myofibroblast origin and behaviour, altered cellular communications, and intracellular signalling pathways are all fundamental pathogenic hallmarks of both IPF and cancer. The concept of IPF as a lethal malignant disorder of the lung might extend beyond the pathogenic link between these two diseases and disclose new pathogenic mechanisms leading to novel therapeutic options, adopted from cancer biology. Moreover, this vision might dawn the awareness of the public, political and scientific community of this devastating disease from an angle different from the current perception and provoke new ideas and studies to get a better understanding to control the otherwise relentless progressive disease.

TGF-β1 targets the GSK-3β/β-catenin pathway via ERK activation in the transition of human lung fibroblasts into myofibroblasts

Transforming growth factor-beta1 (TGF-beta1) is known to induce the transition of human lung fibroblasts to myofibroblasts, a primary event in the pathogenesis of idiopathic pulmonary fibrosis. The molecular pathways involved in myofibroblast transformation are only partially identified. We found that a 24-h treatment with TGF-beta1 (10 ng/ml) induced alpha-smooth actin (SMA) expression and collagen production in human lung fibroblasts. These effects were abrogated by PD98059, a specific inhibitor of the mitogen-activated protein kinase (MAPK) pathway. TGF-beta1 treatment activated the MAPK pathway, as shown by an increased phosphorylation of extracellular-regulated kinases (ERK)1/2 after 30 min of exposure. TGF-beta1 also increased the expression of the Ser-9-phosphorylated inactive form of glycogen synthase kinase-3beta (GSK-3beta), an effect that was largely attenuated by PD98059. A nuclear translocation of beta-catenin in human lung fibroblasts was observed 2h after TGF-beta1 addition both by confocal microscopy and nuclear protein analysis. At this time, TGF-beta1 also increased the total levels of beta-catenin, an effect that was prevented by PD98059. Similarly to TGF-beta1, the GSK-3beta inhibitor lithium chloride (10mM), increased the total levels of beta-catenin and promoted alpha-SMA expression and collagen production. This study demonstrates that TGF-beta1 induces alpha-SMA expression and collagen production in human lung fibroblasts via ERK1/2 activation, GSK-3beta inhibition and nuclear beta-catenin translocation. The evidence that the silencing of beta-catenin by siRNAs was able to prevent the induction of alpha-SMA expression in TGF-beta1-treated fibroblasts further supports the hypothesis of a contribution of the GSK-3beta/beta-catenin pathway in the pathogenesis of idiopathic pulmonary fibrosis.

Effect of rosiglitazone and 15-deoxy-Δ12,14-prostaglandin J2 on bleomycin-induced lung injury

Thiazolidinedione rosiglitazone and 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), are two peroxisome proliferator-activated receptor (PPAR)-γ ligands. The aim of this study was to investigate the effect of rosiglitazone and 15d-PGJ2 on the lung injury caused by bleomycin administration. Mice subjected to intratracheal administration of bleomycin developed significant lung injury. An increase in immunoreactivity to nitrotyrosine, poly(ADP ribose) polymerase (PARP) and inducible nitric oxide synthase as well as a significant loss of body weight and mortality was observed in the lung of bleomycin-treated mice. Administration of the two PPAR-γ agonists rosiglitazone (10 mg·kg−1 i.p.) and 15d-PGJ2 (30 µg·kg−1 i.p.) significantly reduced the: 1) loss of body weight, 2) mortality rate, 3) infiltration of the lung with polymorphonuclear neutrophils (myeloperoxidase activity), 4) oedema formation, and 5) histological evidence of lung injury. Administration of rosiglitazone and 15d-PGJ2 also markedly reduced the nitrotyrosine, PARP and inducible nitric oxide synthase formation. In addition, treatment with the PPAR-γ antagonist bisphenol A diglycidyl ether (1 mg·kg−1 i.p. 30 min before the rosiglitazone or 15d-PGJ2) significantly antagonised the effect of the two PPAR-γ agonists. These results demonstrate that the two peroxisome proliferator-activated receptor-γ agonists, rosiglitazone and 15-deoxy-Δ12,14-prostaglandin J2, significantly reduce lung injury induced by bleomycin in mice.

Inhibition of PI3K Prevents the Proliferation and Differentiation of Human Lung Fibroblasts into Myofibroblasts: The Role of Class I P110 Isoforms

Idiopathic pulmonary fibrosis (IPF) is a progressive fibroproliferative disease characterized by an accumulation of fibroblasts and myofibroblasts in the alveolar wall. Even though the pathogenesis of this fatal disorder remains unclear, transforming growth factor-β (TGF-β)-induced differentiation and proliferation of myofibroblasts is recognized as a primary event. The molecular pathways involved in TGF-β signalling are generally Smad-dependent yet Smad-independent pathways, including phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), have been recently proposed. In this research we established ex-vivo cultures of human lung fibroblasts and we investigated the role of the PI3K/Akt pathway in two critical stages of the fibrotic process induced by TGF-β: fibroblast proliferation and differentiation into myofibroblasts. Here we show that the pan-inhibitor of PI3Ks LY294002 is able to abrogate the TGF-β-induced increase in cell proliferation, in α- smooth muscle actin expression and in collagen production besides inhibiting Akt phosphorylation, thus demonstrating the centrality of the PI3K/Akt pathway in lung fibroblast proliferation and differentiation. Moreover, for the first time we show that PI3K p110δ and p110γ are functionally expressed in human lung fibroblasts, in addition to the ubiquitously expressed p110α and β. Finally, results obtained with both selective inhibitors and gene knocking-down experiments demonstrate a major role of p110γ and p110α in both TGF-β-induced fibroblast proliferation and differentiation. This finding suggests that specific PI3K isoforms can be pharmacological targets in IPF.

Effect of immunotherapy on asthma progression, BHR and sputum eosinophils in allergic rhinitis

Background:  Bronchial hyperresponsiveness (BHR) and airway inflammation are frequently associated with allergic rhinitis, and may be important risk factors for the development of asthma. Specific immunotherapy (SIT) reduces symptom in subjects with allergic rhinitis, but the mechanisms are not clear.

Economic evaluation of sublingual immunotherapy vs symptomatic treatment in adults with pollen-induced respiratory allergy: the Sublingual Immunotherapy Pollen Allergy Italy (SPAI) study

BACKGROUND Few data are available on the pharmacoeconomic aspects of immunotherapy. OBJECTIVE To evaluate, from the health care system and societal perspectives, the costs and consequences of sublingual immunotherapy (SLIT) added to pharmacotherapy compared with drugs alone for respiratory allergy. METHODS This study compared costs, clinical outcomes, and cost-effectiveness ratios of 2 strategies in the management of allergic rhinitis and asthma, namely, SLIT associated with pharmacotherapy and pharmacotherapy alone (no SLIT). A decision tree was developed and populated with epidemiologic and resource utilization data concerning approximately 2,200 patients. Direct costs included visits, tests, pharmacotherapy, immunotherapy, and hospitalizations. Indirect costs and out-of-pocket drugs were also included. Outcome was calculated as the number of improved patients and asthma cases avoided at 6 years. Sensitivity analysis was performed by varying costs and epidemiologic data. RESULTS SLIT improved the symptoms of 399 of 1,000 patients and prevented asthma in 229 of 1,000 patients compared with drugs alone. For SLIT added to pharmacotherapy and pharmacotherapy alone, the direct cost per patient at more than 6 years was Euro2,400 and Euro3,026, whereas the indirect cost was Euro1,913 and Euro3,400. CONCLUSION From both perspectives and for both effectiveness end points, SLIT is less expensive and more effective than pharmacotherapy alone.

Inhibition or knock out of Inducible nitric oxide synthase result in resistance to bleomycin-induced lung injury

BackgroundIn the present study, by comparing the responses in wild-type mice (WT) and mice lacking (KO) the inducible (or type 2) nitric oxide synthase (iNOS), we investigated the role played by iNOS in the development of on the lung injury caused by bleomycin administration. When compared to bleomycin-treated iNOSWT mice, iNOSKO mice, which had received bleomycin, exhibited a reduced degree of the (i) lost of body weight, (ii) mortality rate, (iii) infiltration of the lung with polymorphonuclear neutrophils (MPO activity), (iv) edema formation, (v) histological evidence of lung injury, (vi) lung collagen deposition and (vii) lung Transforming Growth Factor beta1 (TGF-β1) expression.MethodsMice subjected to intratracheal administration of bleomycin developed a significant lung injury. Immunohistochemical analysis for nitrotyrosine revealed a positive staining in lungs from bleomycin-treated iNOSWT mice.ResultsThe intensity and degree of nitrotyrosine staining was markedly reduced in tissue section from bleomycin-iNOSKO mice. Treatment of iNOSWT mice with of GW274150, a novel, potent and selective inhibitor of iNOS activity (5 mg/kg i.p.) also significantly attenuated all of the above indicators of lung damage and inflammation.ConclusionTaken together, our results clearly demonstrate that iNOS plays an important role in the lung injury induced by bleomycin in the mice.

Endothelin-1 Induces Proliferation of Human Lung Fibroblasts and IL-11 Secretion Through an ET A Receptor-Dependent Activation of Map Kinases

Endothelin‐1 (ET‐1) is implicated in the fibrotic responses characterizing interstitial lung diseases, as well as in the airway remodeling process occurring in asthma. Within such a context, the aim of our study was to investigate, in primary cultures of normal human lung fibroblasts (NHLFs), the ET‐1 receptor subtypes, and the intracellular signal transduction pathways involved in the proliferative effects of this peptide. Therefore, cells were exposed to ET‐1 in the presence or absence of an overnight pre‐treatment with either ETA or ETB selective receptor antagonists. After cell lysis, immunoblotting was performed using monoclonal antibodies against the phosphorylated, active forms of mitogen‐activated protein kinases (MAPK). ET‐1 induced a significant increase in MAPK phosphorylation pattern, and also stimulated fibroblast proliferation and IL‐6/IL‐11 release into cell culture supernatants. All these effects were inhibited by the selective ETA antagonist BQ‐123, but not by the specific ETB antagonist BQ‐788. The stimulatory influence of ET‐1 on IL‐11, but not on IL‐6 secretion, was prevented by MAPK inhibitors. Therefore, such results suggest that in human lung fibroblasts ET‐1 exerts a profibrogenic action via an ETA receptor‐dependent, MAPK‐mediated induction of IL‐11 release and cell proliferation.

Effect of indomethacin on adenosine-induced bronchoconstriction

The exact mechanism of adenosine-induced bronchoconstriction in patients with asthma is unknown. Adenosine contraction of guinea pig trachea was antagonized by inhibitors of cyclooxygenase. The aim of this study was to investigate the effect of indomethacin (100 mg/day) on adenosine-induced bronchoconstriction in 14 asymptomatic patients with asthma. Airway response was evaluated as FEV1, and adenosine was administered as an aerosol diluted in 0.9% saline to produce a concentration range of 0.125 to 4 mg/ml. The dose of adenosine producing a 20% change in FEV1 (PD20) was calculated from the individual semilogarithmic dose-response curve; the results of PD20 were converted to log values for statistical analysis (Students paired t test). The study was performed on 3 separate days. On the first day, the adenosine challenge was performed, and on subsequent days patients were pretreated with either placebo or indomethacin in a randomized, double-blind manner. Inhaled adenosine caused bronchoconstriction with a geometric mean PD20 of 0.71 mg (95% confidence limits, 0.44 to 1.16). After placebo, a geometric mean PD20 of 0.91 mg (95% confidence limits, 0.53 to 1.58) was obtained. Indomethacin pretreatment decreased adenosine hyperresponsiveness and shifted the dose-response curves of adenosine challenge to the right with a geometric mean PD20 of 1.28 mg (95% confidence limits, 0.64 to 2.56). The effect of indomethacin on adenosine bronchoconstriction (p less than 0.01 versus baseline; p less than 0.05 versus placebo) suggests an indirect mechanism of adenosine on inducing release of arachidonic acid derivatives. Inflammatory mediators inhibited by indomethacin may be involved in adenosine bronchoconstriction, even if this mechanism is not relevant.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacological inhibition of leukotrienes in an animal model of bleomycin-induced acute lung injury

Leukotrienes are increased locally in idiopathic pulmonary fibrosis. Furthermore, a role for these arachidonic acid metabolites has been thoroughly characterized in the animal bleomycin model of lung fibrosis by using different gene knock-out settings.We investigated the efficacy of pharmacological inhibition of leukotrienes activity in the development of bleomycin-induced lung injury by comparing the responses in wild-type mice with mice treated with zileuton, a 5-lipoxygenase inhibitor and MK-571, a cys-leukotrienes receptor antagonist.Mice were subjected to intra-tracheal administration of bleomycin or saline and were assigned to receive either MK-571 at 1 mg/Kg or zileuton at 50 mg/Kg daily. One week after bleomycin administration, BAL cell counts, lung histology with van Gieson for collagen staining and immunohistochemical analysis for myeloperoxidase, IL-1 and TNF-α were performed.Following bleomycin administration both MK-571 and zileuton treated mice exhibited a reduced degree of lung damage and inflammation when compared to WT mice as shown by the reduction of:(i) loss of body weight, (ii) mortality rate, (iii) lung infiltration by neutrophils (myeloperoxidase activity, BAL total and differential cell counts), (iv) lung edema, (v) histological evidence of lung injury and collagen deposition, (vi) lung myeloperoxidase, IL-1 and TNF-α staining.This is the first study showing that the pharmacological inhibition of leukotrienes activity attenuates bleomycin-induced lung injury in mice. Given our results as well as those coming from genetic studies, it might be considered meaningful to trial this drug class in the treatment of pulmonary fibrosis, a disease that still represents a major challenge to medical treatment.