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Cystic fibrosis (CF) is a genetic disease characterized by chronic bacterial lung infection, most commonly sustained by Pseudomonas aeruginosa. Upon infection, elevated concentrations of pro-inflammatory cytokines (i.e. IL-6 and IL1beta) and chemokines (i.e. IL-8 and GROgamma) are found in the bronchoalveolar fluid of CF patients. We report in this paper that: (a) IL-8, IL-6, IL-1beta, ICAM-1, and GRO-gamma genes are upregulated following infection of CF bronchial epithelial IB3-1 cells with P. aeruginosa; (b) Sp1 transcription factor activity is induced following infection of the cystic fibrosis IB3-1 and CuFi-1 cell lines; (c) inhibition of Sp1 activity using transcription factor decoy molecules leads to inhibition of the expression of IL-6 gene. From the theoretical point of view, our results demonstrate that Sp1 transcription factor activity is induced following infection of CF cells with P. aeruginosa, and that this effect is important in the activation of IL-6 gene transcription. From the practical point of view, our data sustain the potential use of decoy molecules targeting the transcription factor Sp1 to control a relevant molecule involved in the inflammatory process associated with the cystic fibrosis airway pathology.

One of the clinical feature of cystic fibrosis (CF) is a deep inflammatory process, which is characterized by production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against CF to reduce the excessive inflammatory response in the airways of CF patients. Since transcription factor NFkappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. In order to demonstrate that TFD against NFkappaB interferes with the NFkappaB pathway we proved, by chromatin immunoprecipitation (ChIP) that treatment with TFD oligodeoxyribonucleotides of cystic fibrosis IB3-1 cells infected with Pseudomonas aeruginosa leads to a decrease occupancy of the Il-8 gene promoter by NFkappaB factors. In order to develop more stable therapeutic molecules, peptide nucleic acids (PNAs) based agents were considered. In this respect PNA-DNA-PNA (PDP) chimeras are molecules of great interest from several points of view: (1) they can be complexed with liposomes and microspheres; (2) they are resistant to DNases, serum and cytoplasmic extracts; (3) they are potent decoy molecules. By using electrophoretic mobility shift assay and RT-PCR analysis we have demonstrated that (1) the effects of PDP/PDP NFkappaB decoy chimera on accumulation of pro-inflammatory mRNAs in P. aeruginosa infected IB3-1 cells reproduce that of decoy oligonucleotides; in particular (2) the PDP/PDP chimera is a strong inhibitor of IL-8 gene expression; (3) the effect of PDP/PDP chimeras, unlike those of ODN-based decoys, are observed even in the absence of protection with lipofectamine. These informations are of great impact, in our opinion, for the development of stable molecules to be used in non-viral gene therapy of cystic fibrosis. [ABSTRACT FROM AUTHOR]

Chronic inflammatory response in the airway tract of patients affected by cystic fibrosis is characterized by an excessive recruitment of neutrophils to the bronchial lumina, driven by the chemokine interleukin (IL)-8. We previously found that 5-methoxypsoralen reduces Pseudomonas aeruginosa-dependent IL-8 transcription in bronchial epithelial cell lines, with an IC50 of 10 μM (Nicolis E, Lampronti I, Dechecchi MC, Borgatti M, Tamanini A, Bezzerri V, Bianchi N, Mazzon M, Mancini I, Giri MG, Rizzotti P, Gambari R, Cabrini G. Int Immunopharmacol 9: 1411-1422, 2009). Here, we extended the investigation to analogs of 5-methoxypsoralen, and we found that the most potent effect is obtained with 4,6,4′-trimethylangelicin (TMA), which inhibits P. aeruginosa-dependent IL-8 transcription at nanomolar concentration in IB3-1, CuFi-1, CFBE41o-, and Calu-3 bronchial epithelial cell lines. Analysis of phosphoproteins involved in proinflammatory transmembrane signaling evidenced that TMA reduces the phosphorylation of ribosomal S6 kinase-1 and AKT2/3, which we found indeed involved in P. aeruginosa-dependent activation of IL-8 gene transcription by testing the effect of pharmacological inhibitors. In addition, we found a docking site of TMA into NF-κB by in silico analysis, whereas inhibition of the NF-κB/DNA interactions in vitro by EMSA was observed at high concentrations (10 mM TMA). To further understand whether NF-κB pathway should be considered a target of TMA, chromatin immunoprecipitation was performed, and we observed that TMA (100 nM) preincubated in whole living cells reduced the interaction of NF-κB with the promoter of IL-8 gene. These results suggest that TMA could inhibit IL-8 gene transcription mainly by intervening on driving the recruitment of activated transcription factors on IL-8 gene promoter, as demonstrated here for NF-κB. Although the complete understanding of the mechanism of action of TMA deserves further investigation, an activity of TMA on phosphorylating pathways was already demonstrated by our study. Finally, since psoralens have been shown to potentiate cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride transport, TMA was tested and found to potentiate CFTR-dependent chloride efflux. In conclusion, TMA is a dual-acting compound reducing excessive IL-8 expression and potentiating CFTR function. [ABSTRACT FROM AUTHOR]

Shwachman–Diamond syndrome (SDS) is a rare inherited bone marrow failure syndrome, resulting in neutropenia and a risk of myeloid neoplasia. A mutation in a ribosome maturation factor accounts for almost all of the cases. Lymphoid involvement in SDS has not been well characterized. We recently reported that lymphocyte subpopulations are reduced in SDS patients. We have also shown that the mTOR-STAT3 pathway is hyper-activated in SDS myeloid cell populations. Here we show that mTOR-STAT3 signaling is markedly upregulated in the lymphoid compartment of SDS patients. Furthermore, our data reveal elevated IL-6 levels in cellular supernatants obtained from lymphoblasts, bone marrow mononuclear and mesenchymal stromal cells, and plasma samples obtained from a cohort of 10 patients. Of note, everolimus-mediated inhibition of mTOR signaling is associated with basal state of phosphorylated STAT3. Finally, inhibition of mTOR-STAT3 pathway activation leads to normalization of IL-6 expression in SDS cells. Altogether, our data strengthen the hypothesis that SDS affects both lymphoid and myeloid blood compartment and suggest everolimus as a potential therapeutic agent to reduce excessive mTOR-STAT3 activation in SDS. [ABSTRACT FROM AUTHOR]

Abstract: Cystic fibrosis (CF) is characterized by a deep inflammatory process, with production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against IL-8, with the aim of reducing the excessive inflammatory response in the airways of CF patients. Since transcription factor NF-kappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. TFD is based on biomolecules mimicking the target sites of transcription factors (TFs) and able to interfere with TF activity when delivered to target cells. Here, we review the inhibitory effects of decoy oligodeoxyribonucleotides (ODNs) on expression of IL-8 gene and secretion of IL-8 by cystic fibrosis cells infected by Pseudomonas aeruginosa. In addition, the effects of decoy molecules based on peptide nucleic acids (PNAs) are discussed. In this respect PNA–DNA–PNA (PDP) chimeras are interesting: (a) unlike PNAs, they can be complexed with liposomes and microspheres; (b) unlike oligodeoxyribonucleotides (ODNs), they are resistant to DNAses, serum and cytoplasmic extracts; (c) unlike PNA/PNA and PNA/DNA hybrids, they are potent decoy molecules. Interestingly, PDP/PDP NF-kappaB decoy chimeras inhibit accumulation of pro-inflammatory mRNAs (including IL-8 mRNA) in P. aeruginosa infected IB3-1, cells reproducing the effects of decoy oligonucleotides. The effects of PDP/PDP chimeras, unlike ODN-based decoys, are observed even in absence of protection with lipofectamine. Since IL-8 is pivotal in pro-inflammatory processes affecting cystic fibrosis, inhibition of its functions might have a clinical relevance. [ABSTRACT FROM AUTHOR]