Modulation of expression of IL-8 gene in bronchial epithelial cells by 5-methoxypsoralen. Int Immunopharmacol. 2009;9:1411-1422. [PMID: 19720161 DOI: 10.1016/j.intimp.2009.08.013]

Decoding the metabolomic responses of Caragana tibetica to livestock grazing in fragile ecosystems

The population of Caragana tibetica, situated on the edge of the typical grassland-to-desert transition in the Mu Us Sandy Land, plays a vital ecological role in maintaining stability within the regional fragile ecosystem. Despite the consistent growth of C. tibetica following animal grazing, the biological mechanisms underlying its compensatory growth in response to livestock consumption remain unclear. Analyzing 48 metabolomic profiles from C. tibetica, our study reveals that the grazing process induces significant changes in the metabolic pathways of C. tibetica branches. Differential metabolites show correlations with soluble protein content, catalase, peroxidase, superoxide dismutase, malondialdehyde, and proline levels. Moreover, machine learning models built on these differential metabolites accurately predict the intensity of C. tibetica grazing (with an accuracy of 83.3%). The content of various metabolites, indicative of plant stress responses, including Enterolactone, Narceine, and Folcepri, exhibits significant variations in response to varying grazing intensities (P<0.05). Our investigation reveals that elevated grazing intensity intensifies the stress response in C. tibetica, triggering heightened antioxidative defenses and stress-induced biochemical activities. Distinctive metabolites play a pivotal role in responding to stress, facilitating the plant's adaptation to environmental challenges and fostering regeneration.

Traumatic Brain Injury-Mediated Neuroinflammation and Neurological Deficits are Improved by 8-Methoxypsoralen Through Modulating PPARγ/NF-κB Pathway

8-Methoxypsoralen (8-MOP) has anti-inflammatory, antioxidant and tissue-repairing abilities. Here, we probed the function and mechanism of 8-MOP in traumatic brain injury (TBI). The in-vivo TBI model was constructed in Sprague-Dawley (SD) rats using controlled cortical impact (CCI) surgery. In parallel, BV2 microglia and HT22 neurons were activated by lipopolysaccharide (LPS) to establish an in-vitro model. The modified neurological score (mNSS) and the Morris water maze experiment were employed to evaluate the rats' neurological functions. The rats' brain edema was assessed by the dry and wet method, and neuronal apoptosis in damaged brain tissues was monitored by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) and Nissl's staining. Immunohistochemistry (IHC) was applied to verify Iba1-microglial activation in brain lesions of rats. The expression of inflammatory cytokines in BV2 microglia and HT22 neurons in the injured lesion of TBI rats was examined by the enzyme-linked immunosorbent assay (ELISA). The levels of iNOS, COX2, TLR4, PPARγ, STAT3, and NF-κB in brain lesions, BV2 microglia and HT22 neurons were compared by Western blot. As a result, 8-MOP administration reduced inflammation and LPS-induced neuronal damage in BV2 microglia. In vivo, 8-MOP treatment relieved neurological deficits in TBI rats, improved cognitive, learning and motor functions and mitigated brain edema and neuroinflammation induced by TBI. Furthermore, LPS or TBI activated the NF-κB and STAT3 pathways and repressed the PPARγ expression. However, 8-MOP treatment attenuated NF-κB and STAT3 phosphorylation and elevated PPARγ levels. Hence, 8-MOP exerts neuroprotective and anti-inflammatory effects in TBI rats by modulating the PPARγ/NF-κB pathway.

8-Methoxypsoralen has Anti-inflammatory and Antioxidant Roles in Osteoarthritis Through SIRT1/NF-κB Pathway

Osteoarthritis (OA) is mainly manifested by joint pain, stiffness and mobility disorder, which is the main cause of pain and disability in middle-aged and elderly people. In this study, we aimed to explore the role and mechanism of 8-Methoxypsoralen (8-MOP) in the OA model both in vitro and in vivo. The rat chondrocytes were treated with IL-1β, and the proliferation, apoptosis, inflammatory reactions and oxidative stress responses were determined after treatment with different concentrations of 8-MOP. Real-time quantitative polymerase chain reaction (qRT-PCR) and/or Western blot were implemented to check the AMPK/SIRT1/NF-κB expression in chondrocytes. The NF-κB activity was determined by dual luciferase experiment. The pain threshold of OA rat model dealt with 8-MOP and/or the SIRT1 inhibitor EX527 was measured. Our results revealed that 8-MOP evidently reduced IL-1β-mediated apoptosis and inhibition of proliferation, and mitigated the expression of inflammatory cytokines and oxidative stress factors in chondrocytes. Additionally, 8-MOP promoted phosphorylated level of AMPKα, enhanced SIRT1 expression and inhibited the phosphorylation of NF-κB. After treatment with EX527, 8-MOP-mediated protective effects on chondrocytes were mostly reversed. In vivo, 8-MOP obviously improved the pain threshold in the OA rat model and reduced the injury and apoptosis of chondrocytes in the joints. In addition, 8-MOP relieved inflammatory and oxidative stress responses in the articular cartilage via enhancing SIRT1 and repressing NF-κB activation. After the treatment with EX527, the 8-MOP-mediated protective effects were distinctly weakened. In summary, our study testified that 8-MOP alleviates pain, inflammatory and oxidative stress responses in OA rats through the SIRT1/NF-κB pathway, which is expected to become a new reagent for clinical treatment of OA.

Comparative retrospective open-label study of ayurvedic medicines and their combination with allopathic drugs on asymptomatic and mildly-symptomatic COVID-19 patients

Introduction

Treatment for COVID-19 was ambiguous in the beginning of the pandemic. At that time, the conventional medical system was grappling to cope with the rapidly spreading pandemic. The potential of Ayurveda, one of the branches of traditional Indian medicine (TIM), with a 5000 year old history, employing medicines derived from plants and other natural sources, against COVID-19 has been explored through a comparative retrospective open-label study.

Methods

Reported here are the remedial effects of Ayurvedic medicines alone or in combination with Allopathic treatment on 59 asymptomatic or mildly symptomatic COVID-19 patients, across multiple COVID-19 care centers in Ahmedabad, India. The patients were confirmed for COVID-19 infection through RT-qPCR of nasopharyngeal swabs. With informed consents from the patients, the sourced data was divided into ‘Allopathic and Ayurvedic’ [AlloAyur] (n = 41) and ‘Ayurvedic only’[Ayur] (n = 18) groups, based on the type of treatment the patients decided to receive, that is Ayurvedic medicines with Allopathic treatment or Ayurvedic medicines alone, respectively. Ayurvedic medicines included oral doses and nasal drops; the dosage and regime were decided based on the recommendations from Ayurvedic texts. The Allopathic medicines included Azithromycin, Vitamin-C and anti-histamines. Acetaminophen was also administered when necessary, by the attending physician. The patients were observed for symptomatic improvement.

Results

Primary outcome of this study was the symptomatic relief from COVID-19. Data collected over a period of two months, showed that more patients exhibited symptomatic relief in Ayur goup (83.33 %) than in the AlloAyur group (48.78 %) within the first 13 days of treatment. No visible adverse effects were observed. This indicated faster and safe symptomatic resolution among those treated with Ayurvedic medicines alone.

Conclusion

Patients receiving only Ayurvedic medicines on average were symptomatically relieved faster than those receiving Allopathic and Ayurvedic medicines together.

Role of Cystic Fibrosis Bronchial Epithelium in Neutrophil Chemotaxis

A hallmark of cystic fibrosis (CF) chronic respiratory disease is an extensive neutrophil infiltrate in the mucosa filling the bronchial lumen, starting early in life for CF infants. The genetic defect of the CF Transmembrane conductance Regulator (CFTR) ion channel promotes dehydration of the airway surface liquid, alters mucus properties, and decreases mucociliary clearance, favoring the onset of recurrent and, ultimately, chronic bacterial infection. Neutrophil infiltrates are unable to clear bacterial infection and, as an adverse effect, contribute to mucosal tissue damage by releasing proteases and reactive oxygen species. Moreover, the rapid cellular turnover of lumenal neutrophils releases nucleic acids that further alter the mucus viscosity. A prominent role in the recruitment of neutrophil in bronchial mucosa is played by CF bronchial epithelial cells carrying the defective CFTR protein and are exposed to whole bacteria and bacterial products, making pharmacological approaches to regulate the exaggerated neutrophil chemotaxis in CF a relevant therapeutic target. Here we revise: (a) the major receptors, kinases, and transcription factors leading to the expression, and release of neutrophil chemokines in bronchial epithelial cells; (b) the role of intracellular calcium homeostasis and, in particular, the calcium crosstalk between endoplasmic reticulum and mitochondria; (c) the epigenetic regulation of the key chemokines; (d) the role of mutant CFTR protein as a co-regulator of chemokines together with the host-pathogen interactions; and (e) different pharmacological strategies to regulate the expression of chemokines in CF bronchial epithelial cells through novel drug discovery and drug repurposing.

Protective effect of bergapten in acetic acid-induced colitis in rats

Bergapten (5-methoxysporalen) is a furanocoumarin extracted from several species of citrus and bergamot oil. Bergamot essential oil is used traditionally in the management of inflammatory conditions. Previous studies on bergapten have explored mainly its in vitro anti-inflammatory activities which include suppression of the expression and release of pro-inflammatory cytokines such as TNF-α and interleukins as well as prostaglandins. Bergapten enhances the clearance of neutrophils and macrophages from the site of inflammation and reduces oxidative stress by inhibition of reactive oxygen species (ROS). Bergapten was assessed for its anti-inflammatory properties in acetic acid-induced colitis. Animals were obtained and randomly placed in six (6) groups (n = 5) after acclimatization. Colitis was induced by rectal administration using 4% v/v acetic acid in Sprague Dawley rats after pre-treatment for 5 days. Bergapten was administered at doses of 3, 10, and 30 mg kg-1 p.o. while the control group received saline 5 mL kg-1 p.o. and the standard drug employed was sulphasalazine at a dose of 500 mg kg-1. Assessments made for colon-weight-to-length ratio, colonic injury, and mucosal mast cell degranulation. There were reduced colon-weight-to-length ratios in animals treated with bergapten which was significant (p < 0.5) for doses 10 and 30 mg kg-1 compared to the disease control group Both macroscopic and microscopic damage were reduced as well, with a lesser percentage of degranulated mast cells. Macroscopic damage was reduced for bergapten at doses 10 and 30 mg kg-1 significantly at p < 0.5 and p < 0.001, respectively. Similarly, microscopic damage was reduced at p < 0.01 and p < 0.001 respectively for bergapten 10 and 30 mg kg-1. The reduction of degranulation by bergapten was significant at p < 0.001. There was generally reduced damage at inflammatory sites as well as decreased infiltration of inflammatory cells. Overall, bergapten reduces inflammation in acetic acid-induced colitis.

Furocoumarins as multi-target agents in the treatment of cystic fibrosis

Multi-target molecular entities, offer a path to progress both in understanding causes of disease and in defining effective small molecule treatments. Coumarin and its derivatives belong to an important group of natural compounds with diverse biological properties. They are found in vegetables and plants for which literature reports thousands of publications for the great variety of biological applications among which the photoprotective effects, thus being considered multi-targeting agents. Their furan condensed analogues constitute the family of furocoumarins, less represented in the literature, endowed with photosensitizing properties and often used for the treatment of skin diseases such as vitiligo and psoriasis. Despite the study of biological properties of linear and angular furocumarins dates back to ancient times, mainly as photosensitizers, these small molecules still represent an attractive scaffold for further development and applications in several therapeutic fields. The aim of the present review is to summarize the most promising chemical entities belonging to the class of furocumarins and coumarins, emerged in the last decades, and the methods used for their synthesis with a particular focus on main targets involved in the cystic fibrosis treatment.

β-Sitosterol Reduces the Expression of Chemotactic Cytokine Genes in Cystic Fibrosis Bronchial Epithelial Cells

Extracts from Nigella arvensis L. seeds, which are widely used as anti-inflammatory remedies in traditional medicine of Northern Africa, were able to inhibit the expression of the pro-inflammatory neutrophil chemokine Interleukin (IL)-8 in Cystic Fibrosis (CF) bronchial epithelial IB3-1 cells exposed to the Gram-negative bacterium Pseudomonas aeruginosa. The chemical composition of the extracts led to the identification of three major components, β-sitosterol, stigmasterol, and campesterol, which are the most abundant phytosterols, cholesterol-like molecules, usually found in plants. β-sitosterol (BSS) was the only compound that significantly reproduced the inhibition of the P. aeruginosa-dependent expression of IL-8 at nanomolar concentrations. BSS was tested in CF airway epithelial CuFi-1 cells infected with P. aeruginosa. BSS (100 nM), showed a significant and consistent inhibitory activity on expression of the P. aeruginosa-stimulated expression chemokines IL-8, GRO-α GRO-β, which play a pivotal role in the recruitment of neutrophils in CF inflamed lungs. Preliminary mechanistic analysis showed that BSS partially inhibits the P. aeruginosa-dependent activation of Protein Kinase C isoform alpha, which is known to be involved in the transmembrane signaling activating IL-8 gene expression in bronchial epithelial cells. These data indicate BSS as a promising molecule to control excessive lung inflammation in CF patients.

Phloridzin derivatives inhibiting pro-inflammatory cytokine expression in human cystic fibrosis IB3-1 cells

Cystic Fibrosis (CF) is the most diffuse autosomal recessive genetic disease affecting Caucasians. A persistent recruitment of neutrophils in the bronchi of CF patients contributes to exacerbate the airway tissue damage, suggesting that modulation of chemokine expression may be an important target for the patient's well being thus the identification of innovative anti-inflammatory drugs is considered a longterm goal to prevent progressive tissue deterioration. Phloridzin, isolated from Malus domestica by a selective molecular imprinting extraction, and its structural analogues, Phloridzin heptapropionate (F1) and Phloridzin tetrapropionate (F2), were initially investigated because of their ability to reduce IL-6 and IL-8 expression in human CF bronchial epithelial cells (IB3-1) stimulated with TNF-α. Release of these cytokines by CF cells was shown to be controlled by the Transcription Factor (TF) NF-kB. The results of the present investigation show that of all the derivatives tested, Phloridzin tetrapropionate (F2) is the most interesting and has greatest potential as it demonstrates inhibitory effects on the expression and production of different cytokines involved in CF inflammation processes, including RANTES, VEGF, GM-CSF, IL-12, G-CSF, MIP-1b, IL-17, IL-10 and IP-10, without any correlated anti-proliferative and pro-apoptotic effects.

Antibacterial and anti-inflammatory activity of a temporin B peptide analogue on an in vitro model of cystic fibrosis

Natural peptides with antimicrobial properties are deeply investigated as tools to fight bacteria resistant to common antibiotics. Small peptides, as those belonging to the temporin family, are very attractive because their activity can easily be tuned after small modification to their primary sequence. Structure-activity studies previously reported by us allowed the identification of one peptide, analogue of temporin B, TB_KKG6A, showing, unlike temporin B, antimicrobial activity against both Gram-positive and Gram-negative bacteria. In this paper, we investigated the antimicrobial and anti-inflammatory activity of the peptide TB_KKG6A against Pseudomonas aeruginosa. Interestingly, we found that the peptide exhibits antimicrobial activity at low concentrations, being able to downregulate the pro-inflammatory chemokines and cytokines interleukin (IL)-8, IL-1β, IL-6 and tumor necrosis factor-α produced downstream infected human bronchial epithelial cells. Experiments were carried out also with temporin B, which was found to show pro-inflammatory activity. Details on the interaction between TB_KKG6A and the P. aeruginosa LPS were obtained by circular dichroism and fluorescence studies.

Rescuing ΔF508 CFTR with trimethylangelicin, a dual-acting corrector and potentiator

Since the discovery of the cystic fibrosis (CF) gene that encodes the CF transmembrane conductance regulator (CFTR) in 1989, there has been considerable progress in understanding the molecular defects associated with different mutations in the CFTR protein. Small molecule "potentiators" have led the way as a drug therapeutic approach for correcting channel gating mutations such as the G551D mutation. Therapies for correcting the most common folding mutation in CFTR, ΔF508, however, have proven to be much more challenging. The protein-folding problem appears to be associated with both nucleotide binding domain (NBD) instability and domain interface interactions that are caused by the loss of the phenylalanine residue in NBD 1. Given the inherent complexity in the sequential folding pathway for this very large multidomain protein, it has been suggested that correcting the proper folding, anion channel function, and cell surface stability of the ΔF508 CFTR protein will require a multidrug approach to fix each of these compounding problems. Here we discuss a recent publication (Favia M, Mancini MT, Bezzerri V, Guerra L, Laselva O, Abbattiscianni AC, Debellis L, Reshkin SJ, Gambari R, Cabrini G, Casavola V. Am J Physiol Lung Cell Mol Physiol 307: L48-L61, 2014), however, that offers hope that single drug therapies are still possible.

Modulation of the expression of the proinflammatory IL-8 gene in cystic fibrosis cells by extracts deriving from olive mill waste water

A persistent recruitment of neutrophils in the bronchi of cystic fibrosis (CF) patients contributes to aggravate the airway tissue damage, suggesting the importance of modulating the expression of chemokines, including IL-8 during the management of the CF patients. Polyphenols rich extracts derived from waste water from olive mill, obtained by a molecular imprinting approach, have been investigated in order to discover compounds able to reduce IL-8 expression in human bronchial epithelial cells (IB3-1 cells), derived from a CF patient with a ΔF508/W1282X mutant genotype and stimulated with TNF-alpha. Initially, electrophoretic mobility shift assays (EMSAs) were performed to determine whether the different active principles were able to inhibit the binding between transcription factor (TF) NF-kappaB and DNA consensus sequences. Among different representative active principles present in the extract, three compounds were selected, apigenin, oleuropein, and cyanidin chloride, which displayed remarkable activity in inhibiting NF-kappaB/DNA complexes. Utilizing TNF-alpha-treated IB3-1 cells as experimental model system, we demonstrated that apigenin and cyanidin chloride are able to modulate the expression of the NF-kappaB-regulated IL-8 gene, while oleuropein showed no effect in regulating the expression of the gene IL-8.

Psoralen derivatives as inhibitors of NF-κB/DNA interaction: synthesis, molecular modeling, 3D-QSAR, and biological evaluation

Some new psoralen derivatives were synthesized and evaluated as inhibitors of NF-κB/DNA interaction, with the aim to investigate the structural determinants required to inhibit this interaction. Starting from molecular docking studies, several possible protein binding sites were proposed and several three-dimensional quantitative structure-activity relationship (3D-QSAR) models were built using the docked poses of 29 (the most active psoralen in the series) as templates for alignment of the inhibitors. The selected best model was validated through the prediction of the activity of 17 novel compounds. All the experimental data agreed with the computational experiments, supporting the reliability of the computational approach. The hypothesis about the interaction with NF-κB was also supported by surface plasmon resonance based assays using compound 29. All the collected data allowed the identification of compound 29 as a potential candidate for the development of pharmaceutical strategies against the inflammatory phenotype of cystic fibrosis.

MicroRNA Expression in Cystic Fibrosis Airway Epithelium

MicroRNAs (miRs) have emerged as major regulators of the protein content of a cell. In the most part, miRs negatively regulate target mRNA expression, with sets of miRs predicted to regulate certain signaling pathways. The miR expression profile of endobronchial brushings is altered in people with cystic fibrosis (CF) compared to those without CF. How this impacts on CF has important implications for our growing understanding of the pathophysiology of CF lung disease and the development of new therapeutics to treat its pulmonary manifestations. Herein we discuss the potential consequences of altered miR expression in CF airway epithelium particularly with respect to cystic fibrosis transmembrane conductance regulator (CFTR) expression, innate immunity and toll-like receptor signalling and explore how best to exploit these changes for therapeutic benefit.

Protective effects of 5-methoxypsoralen against acetaminophen-induced hepatotoxicity in mice

AIM: To investigate the hepatic protective effects of 5-methoxypsoralen (5-MOP) and to learn if 5-MOP causes hepatotoxicity at protective doses.

METHODS: C57BL/6J mice were administrated orally with 5-MOP at doses of 12.5, 25 and 50 mg/kg body weight respectively every morning for 4 d before given acetaminophen (APAP) subcutaneously at a dose of 500 mg/kg. The 5-MOP alone group was treated with 5-MOP orally at a dose of 50 mg/kg body weight for 4 d without APAP. Twenty-four hours after APAP administration, blood samples of mice were analyzed for serum enzyme alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) levels, and malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG) of liver tissues were measured and histopathologic changes of the liver were observed.

RESULTS: Compared with the vehicle control group, the serum levels (IU/L) of ALT, AST and LDH were all increased significantly in APAP group (8355 ± 3940 vs 30 ± 21, P < 0.05; 6482 ± 4018 vs 146 ± 58, P < 0.05; 24627 ± 10975 vs 1504 ± 410, P < 0.05). Compared with APAP group, the serum ALT levels (IU/L) (1674 ± 1810 vs 8355 ± 3940, P < 0.05; 54 ± 39 vs 8355 ± 3940, P < 0.05; 19 ± 9 vs 8355 ± 3940, P < 0.05), AST levels (IU/L) (729 ± 685 vs 6482 ± 4108, P < 0.05; 187 ± 149 vs 6482 ± 4108, P < 0.05; 141 ± 12 vs 6482 ± 4108, P < 0.05) and LDH levels (IU/L) (7220 ± 6317 vs 24 627 ± 10 975, P < 0.05; 1618 ± 719 vs 24 627 ± 10 975, P < 0.05; 1394 ± 469 vs 24 627 ± 10 975, P < 0.05) were all decreased drastically in the three-dosage 5-MOP pretreatment groups. Pretreatment of 5-MOP could attenuate histopathologic changes induced by APAP, including hepatocellular necrosis and infiltration of inflammatory cells, and the effect was dose-dependent. MDA levels (nmol/mg) were decreased by 5-MOP in a dose-dependent manner (0.98 ± 0.45 vs 2.15 ± 1.07, P > 0.05; 0.59 ± 0.07 vs 2.15 ± 1.07, P < 0.05; 0.47 ± 0.06 vs 2.15 ± 1.07, P < 0.05). The pretreatment of 5-MOP could also increase the GSH/GSSG ratio (3.834 ± 0.340 vs 3.306 ± 0.282, P > 0.05; 5.330 ± 0.421 vs 3.306 ± 0.282, P < 0.05; 6.180 ± 0.212 vs 3.306 ± 0.282, P < 0.05). In the group treated with 5-MOP but without APAP, the serum enzyme levels, the liver histopathologic manifestation, and the values of MDA and GSH/GSSG ratio were all normal.

CONCLUSION: 5-MOP can effectively protect C57BL/6J mice from APAP-induced hepatotoxicity and possesses an antioxidative activity, and does not cause liver injury at the protective doses.

Corilagin is a potent inhibitor of NF-kappaB activity and downregulates TNF-alpha induced expression of IL-8 gene in cystic fibrosis IB3-1 cells

Corilagin (beta-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose), a gallotannin identified in several plants, including Phyllanthus urinaria, has been shown to exhibit versatile medicinal activities. As far as possible anti-inflammatory effects of corilagin, only few reports are available, and the potential use of corilagin as possible therapeutic molecule for cystic fibrosis has not been evaluated. In the present paper we report experiments aimed at determining the activity of corilagin on nuclear factor kappaB (NF-kappaB) binding to DNA target and on the expression of the major pro-inflammatory gene involved in cystic fibrosis, interleukin-8 (IL-8). Both IL-8 mRNA content and IL-8 protein secretion were analyzed in cystic fibrosis bronchial IB3-1 cells stimulated by tumor necrosis factor-alpha (TNF-alpha), one of the most potent pro-inflammatory agents. The data obtained demonstrate that corilagin binds to NF-kappaB, inhibits NF-kappaB/DNA interactions and affects IL-8 gene expression in TNF-alpha treated IB3-1 cells. In addition, corilagin inhibits TNF-alpha induced secretion of MCP-1 and RANTES, exhibiting low or no effect on the release of G-CSF, IL-6 and VEGF. Therefore, corilagin might be of interest for experimental anti-inflammatory therapy of cystic fibrosis.

Trimethylangelicin reduces IL-8 transcription and potentiates CFTR function

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.