title: Trimethylangelicin reduces IL-8 transcription and potentiates CFTR function.
abstract: 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 IC(50) 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.
authors.affiliation: Laboratory of Molecular Pathology, Univ. Hospital of Verona, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Tamanini
authors.forename: Monica
authors.initials: M
authors.lastname: Borgatti
authors.forename: Alessia
authors.initials: A
authors.lastname: Finotti
authors.forename: Laura
authors.initials: L
authors.lastname: Piccagli
authors.forename: Valentino
authors.initials: V
authors.lastname: Bezzerri
authors.forename: Maria
authors.initials: M
authors.lastname: Favia
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Guerra
authors.forename: Ilaria
authors.initials: I
authors.lastname: Lampronti
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Bianchi
authors.forename: Francesco
authors.initials: F
authors.lastname: Dall'Acqua
authors.forename: Daniela
authors.initials: D
authors.lastname: Vedaldi
authors.forename: Alessia
authors.initials: A
authors.lastname: Salvador
authors.forename: Enrica
authors.initials: E
authors.lastname: Fabbri
authors.forename: Irene
authors.initials: I
authors.lastname: Mancini
authors.forename: Elena
authors.initials: E
authors.lastname: Nicolis
authors.forename: Valeria
authors.initials: V
authors.lastname: Casavola
authors.forename: Giulio
authors.initials: G
authors.lastname: Cabrini
authors.forename: Roberto
authors.initials: R
authors.lastname: Gambari
mesh_terms: D001980:Bronchi / Q000166:cytology; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D011564:Furocoumarins / Q000737:chemistry / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics* / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects*; D014307:Trioxsalen / Q000737:chemistry / Q000494:pharmacology
chemical_list: D002712:Chlorides; D011564:Furocoumarins; D016209:Interleukin-8; D016328:NF-kappa B; D010750:Phosphoproteins; D012333:RNA, Messenger; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C041621:4,4',6-trimethylangelicin; D014307:Trioxsalen