A pathogenic role for cystic fibrosis transmembrane conductance regulator in celiac disease.

Intestinal handling of dietary proteins usually prevents local inflammatory and immune responses and promotes oral tolerance. However, in ~ 1% of the world population, gluten proteins from wheat and related cereals trigger an HLA DQ2/8-restricted TH1 immune and antibody response leading to celiac disease. Prior epithelial stress and innate immune activation are essential for breaking oral tolerance to the gluten component gliadin. How gliadin subverts host intestinal mucosal defenses remains elusive. Here, we show that the α-gliadin-derived LGQQQPFPPQQPY peptide (P31-43) inhibits the function of cystic fibrosis transmembrane conductance regulator (CFTR), an anion channel pivotal for epithelial adaptation to cell-autonomous or environmental stress. P31-43 binds to, and reduces ATPase activity of, the nucleotide-binding domain-1 (NBD1) of CFTR, thus impairing CFTR function. This generates epithelial stress, tissue transglutaminase and inflammasome activation, NF-κB nuclear translocation and IL-15 production, that all can be prevented by potentiators of CFTR channel gating. The CFTR potentiator VX-770 attenuates gliadin-induced inflammation and promotes a tolerogenic response in gluten-sensitive mice and cells from celiac patients. Our results unveil a primordial role for CFTR as a central hub orchestrating gliadin activities and identify a novel therapeutic option for celiac disease.

Clinical course and risk factors for severe COVID-19 among Italian patients with cystic fibrosis: a study within the Italian Cystic Fibrosis Society.

PURPOSE: To describe the clinical course of COVID-19 in patients with cystic fibrosis (CF) and to identify risk factors for severe COVID-19. METHODS: We conducted a prospective study within the Italian CF Society. CF centers collected baseline and follow-up data of patients with virologically confirmed SARS-CoV-2 infection between March 2020 and June 2021. Odds ratios (ORs) for severe SARS-CoV-2 (as defined by hospital admission) were estimated by logistic regression models. RESULTS: The study included 236 patients with positive molecular test for SARS-CoV-2. Six patients died, 43 patients were admitted to hospital, 4 admitted to intensive care unit. Pancreatic insufficiency was associated with increased risk of severe COVID-19 (OR 4.04, 95% CI 1.52; 10.8). After adjusting for age and pancreatic insufficiency, forced expiratory volume in one second (FEVp) < 40% (OR 4.54, 95% CI 1.56; 13.2), oxygen therapy (OR 12.3, 95% CI 2.91-51.7), underweight (OR 2.92, 95% CI 1.12; 7.57), organ transplantation (OR 7.31, 95% CI 2.59; 20.7), diabetes (OR 2.67, 95% CI 1.23; 5.80) and liver disease (OR 3.67, 95% CI 1.77; 7.59) were associated with increased risk of severe COVID-19, while use of dornase alfa was associated with a reduced risk (OR 0.34, 95% CI 0.13-0.88). No significant changes were observed in FEVp from baseline to a median follow-up of 2 months (median difference: 0, interquartile range: - 4; 5, P = 0.62). CONCLUSION: Clinical features indicative of severe form of CF are associated with increased risk of COVID-19 hospitalization. SARS-CoV-2 infected patients do not experience a deterioration of respiratory function.

TG2 regulates the heat-shock response by the post-translational modification of HSF1.

Heat-shock factor 1 (HSF1) is the master transcription factor that regulates the response to proteotoxic stress by controlling the transcription of many stress-responsive genes including the heat-shock proteins. Here, we show a novel molecular mechanism controlling the activation of HSF1. We demonstrate that transglutaminase type 2 (TG2), dependent on its protein disulphide isomerase activity, triggers the trimerization and activation of HSF1 regulating adaptation to stress and proteostasis impairment. In particular, we find that TG2 loss of function correlates with a defect in the nuclear translocation of HSF1 and in its DNA-binding ability to the HSP70 promoter. We show that the inhibition of TG2 restores the unbalance in HSF1-HSP70 pathway in cystic fibrosis (CF), a human disorder characterized by deregulation of proteostasis. The absence of TG2 leads to an increase of about 40% in CFTR function in a new experimental CF mouse model lacking TG2. Altogether, these results indicate that TG2 plays a key role in the regulation of cellular proteostasis under stressful cellular conditions through the modulation of the heat-shock response.

GH-IGF-1 Axis in Children with Cystic Fibrosis.

OBJECTIVE: To verify whether growth hormone receptor (GHR) gene expression plays a role in growth of children with cystic fibrosis (CF), as a consequence of the chronic inflammatory condition and malnutrition. DESIGN: We enrolled 49 prepubertal patients (24 males and 25 females) affected by CF in a stable clinical condition, 19 of whom had been diagnosed through newborn screening and 30 following presentation of symptoms. Patients had no significant comorbidity affecting growth or cystic fibrosis transmembrane conductance regulator (CFTR)-related diabetes requiring insulin therapy. Blood was collected during two follow-up visits to measure insulin-like growth factor (IGF-I), growth hormone-binding protein (GHBP), and GHR gene expression. Recruited as a control group were 52 healthy children, sex- and age-matched, were recruited as a control group. METHODS: We compared body mass index (BMI), height, weight, IGF-I, GHBP, and GHR gene expression values (evaluated by Chemiluminescent Immunometric assay; ELISA and real-time PCR, respectively) in CF patients diagnosed through newborn screening (NBS) or by symptoms (late diagnosis [LD]) and in healthy controls. RESULTS: BMI increased significantly in patients between the time of diagnosis and check-up (P<0.001), particularly in the LD group; median value was lower at diagnosis and significantly higher (P<0.001) at follow-up visits compared to controls. At initial evaluation, higher levels of IGF-I (not statistically significant) were found in both the NBS group and the LD group compared to the control group. At the second evaluation, significantly higher levels of IGF-I (P=0.003) were found in both the NBS and LD groups compared to controls; GHR mRNA expression had significantly increased (P=0.013) in LD patients compared with the first evaluation and was significantly higher in the NBS and LD groups than in controls. GHBP values had significantly increased (P=0.047) in the NBS group after one year of therapy compared to first visit levels and were significantly higher (P<0,0001) in the NBS and LD groups compared to controls. CONCLUSION: In our LD patients during childhood, we observed good auxological values and a GH/IGF-I axis function within normal range for the factor evaluated. However, earlier diagnosis through NBS might further minimize and prevent growth retardation, by reducing the duration of symptoms before treatment.

Mutation-specific therapies and drug repositioning in cystic fibrosis.

Cystic fibrosis (CF) is an inherited, prematurely lethal rare disease affecting more than 85,000 people worldwide. CF is caused by more than 2000 loss-of-function mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). This review summarizes recent advances in the etiological therapies of CF that aim at repairing the functional defect of CFTR by means of CFTR modulators. We will discuss the state of art of the mutation-specific treatments that are designed to target different steps of the CFTR biogenesis perturbed by mutations in CFTR gene. Moreover, we will discuss how drug repositioning, namely the use of drugs already approved for the treatment of other human diseases, may be repurposed in CF patients to circumvent CFTR dysfunction. Finally, we highlight how the combined use of two or more compounds acting on different disease mechanisms is required to achieve clinical benefit in CF population.

Inhaled medications in cystic fibrosis beyond antibiotics.

Structural lung disease begins very early in children with cystic fibrosis (CF), often in the first three months of life. Inhaled medications represent an attractive therapeutic approach in CF that are routinely used as early intervention strategies. Two aerosolized solutions, hypertonic saline and dornase alfa, have significant potential benefits by improving mucociliary clearance, with minimal associated side-effects. In particular, they favor rehydration of airway surface liquid and cleavage of extracellular DNA in the airways, respectively, consequently reducing rate of pulmonary disease exacerbations. Indirect anti-inflammatory effects have been documented for both drugs, addressing each of the three interrelated elements in the vicious cycle of lung disease in CF: airway obstruction, inflammation and infection. This short review aimed to summarize the main papers that support potential clinical impact of inhaled solutions on pulmonary disease in CF.

Personalization of therapies in rare diseases: a translational approach for the treatment of cystic fibrosis.

High variability in the response rates to treatments can make the interpretation of data from clinical trials very difficult, particularly in rare genetic diseases in which the enrolment of thousands of patients is problematic. Personalized medicine largely depends on the establishment of appropriate early detectors of drug efficacy that may guide the administration (or discontinuation) of specific treatments. Such biomarkers should be capable of predicting the therapeutic response of individual patients and of monitoring early benefits of candidate drugs before late clinical benefits become evident. The identification of these biomarkers implies a rigorous stepwise process of translation from preclinical evaluation in cultured cells, suitable animal models or patient-derived freshly isolated cells to clinical application. In this review, we will discuss how a process of research translation can lead to the implementation of functional and mechanistic disease-relevant biomarkers. Moreover, we will address how preclinical data can be translated into the clinic in a personalized medical approach that can provide the right drug to the right patient within the right timeframe.

Trans-heterozygosity for mutations enhances the risk of recurrent/chronic pancreatitis in patients with Cystic Fibrosis.

BACKGROUND: Recurrent (RP) and chronic pancreatitis (CP) may complicate Cystic Fibrosis (CF). It is still unknown if mutations in genes involved in the intrapancreatic activation of trypsin (IPAT) or in the pancreatic secretion pathway (PSP) may enhance the risk for RP/CP in patients with CF. METHODS: We enrolled: 48 patients affected by CF complicated by RP/CP and, as controls 35 patients with CF without pancreatitis and 80 unrelated healthy subjects. We tested a panel of 8 genes involved in the IPAT, i.e. PRSS1, PRSS2, SPINK1, CTRC, CASR, CFTR, CTSB and KRT8 and 23 additional genes implicated in the PSP. RESULTS: We found 14/48 patients (29.2%) with mutations in genes involved in IPAT in the group of CF patients with RP/CP, while mutations in such genes were found in 2/35 (5.7%) patients with CF without pancreatitis and in 3/80 (3.8%) healthy subjects (p < 0.001). Thus, we found mutations in 12 genes of the PSP in 11/48 (22.9%) patients with CF and RP/CP. Overall, 19/48 (39.6%) patients with CF and RP/CP showed one or more mutations in the genes involved in the IPAT and in the PSP while such figure was 4/35 (11.4%) for patients with CF without pancreatitis and 11/80 (13.7%) for healthy controls (p < 0.001). CONCLUSIONS: The trans-heterozygous association between CFTR mutations in genes involved in the pathways of pancreatic enzyme activation and the pancreatic secretion may be risk factors for the development of recurrent or chronic pancreatitis in patients with CF.

Genotype-phenotype correlation and functional studies in patients with cystic fibrosis bearing CFTR complex alleles.

BACKGROUND: The effect of complex alleles in cystic fibrosis (CF) is poorly defined for the lack of functional studies. OBJECTIVES: To describe the genotype-phenotype correlation and the results of either in vitro and ex vivo studies performed on nasal epithelial cells (NEC) in a cohort of patients with CF carrying cystic fibrosis transmembrane conductance regulator (CFTR) complex alleles. METHODS: We studied 70 homozygous, compound heterozygous or heterozygous for CFTR mutations: p.[Arg74Trp;Val201Met;Asp1270Asn], n=8; p.[Ile148Thr;Ile1023_Val1024del], n=5; p.[Arg117Leu;Leu997Phe], n=6; c.[1210-34TG[12];1210-12T[5];2930C>T], n=3; p.[Arg74Trp;Asp1270Asn], n=4; p.Asp1270Asn, n=2; p.Ile148Thr, n=6; p.Leu997Phe, n=36. In 39 patients, we analysed the CFTR gating activity on NEC in comparison with patients with CF (n=8) and carriers (n=4). Finally, we analysed in vitro the p.[Arg74Trp;Val201Met;Asp1270Asn] complex allele. RESULTS: The p.[Ile148Thr;Ile1023_Val1024del] caused severe CF in five compound heterozygous with a class I-II mutation. Their CFTR activity on NEC was comparable with patients with two class I-II mutations (mean 7.3% vs 6.9%). The p.[Arg74Trp;Asp1270Asn] and the p.Asp1270Asn have scarce functional effects, while p.[Arg74Trp;Val201Met;Asp1270Asn] caused mild CF in four of five subjects carrying a class I-II mutation in trans, or CFTR-related disorders (CFTR-RD) in three having in trans a class IV-V mutation. The p.[Arg74Trp;Val201Met;Asp1270Asn] causes significantly (p<0.001) higher CFTR activity compared with compound heterozygous for class I-II mutations. Furthermore, five of six compounds heterozygous with the p.[Arg117Leu;Leu997Phe] had mild CF, whereas the p.Leu997Phe, in trans with a class I-II CFTR mutation, caused CFTR-RD or a healthy status (CFTR activity: 21.3-36.9%). Finally, compounds heterozygous for the c.[1210-34TG[12];1210-12T[5];2930C>T] and a class I-II mutation had mild CF or CFTR-RD (gating activity: 18.5-19.0%). CONCLUSIONS: The effect of complex alleles partially depends on the mutation in trans. Although larger studies are necessary, the CFTR activity on NEC is a rapid contributory tool to classify patients with CFTR dysfunction.

Clinical expression of cystic fibrosis in a large cohort of Italian siblings.

BACKGROUND: A clinical heterogeneity was reported in patients with Cystic Fibrosis (CF) with the same CFTR genotype and between siblings with CF. METHODS: We investigated all clinical aspects in a cohort of 101 pairs of siblings with CF (including 6 triplets) followed since diagnosis. RESULTS: Severe lung disease had a 22.2% concordance in sib-pairs, occurred early and the FEV1% at 12 years was predictive of the severity of lung disease in the adulthood. Similarly, CF liver disease occurred early (median: 15 years) and showed a concordance of 27.8% in sib-pairs suggesting a scarce contribution of genetic factors; in fact, only 2/15 patients with liver disease in discordant sib-pairs had a deficiency of alpha-1-antitrypsin (a known modifier gene of CF liver phenotype). CF related diabetes was found in 22 pairs (in 6 in both the siblings). It occurred later (median: 32.5 years) and is strongly associated with liver disease. Colonization by P. aeruginosa and nasal polyposis that required surgery had a concordance > 50% in sib-pairs and were poorly correlated to other clinical parameters. The pancreatic status was highly concordant in pairs of siblings (i.e., 95.1%) but a different pancreatic status was observed in patients with the same CFTR mutations. This suggests a close relationship of the pancreatic status with the "whole" CFTR genotype, including mutations in regulatory regions that may modulate the levels of CFTR expression. Finally, a severe course of CF was evident in a number of patients with pancreatic sufficiency. CONCLUSIONS: Physicians involved in care of patients with CF and in genetic counseling must be aware of the clinical heterogeneity of CF even in sib-pairs that, at the state of the art, is difficult to explain.

Reduced absorption and enhanced synthesis of cholesterol in patients with cystic fibrosis: a preliminary study of plasma sterols.

BACKGROUND: Low cholesterol is typically observed in the plasma of patients with cystic fibrosis (CF) contrasting with the subcellular accumulation of cholesterol demonstrated in CF cells and in mice models. However, the homeostasis of cholesterol has not been well investigated in patients with CF. METHODS: We studied the plasma of 26 patients with CF and 33 unaffected controls campesterol and ß-sitosterol as markers of intestinal absorption and lathosterol as a marker of de novo cholesterol biosynthesis by gas chromatography (GC-FID and GC-MS). RESULTS: Plasma campesterol and ß-sitosterol results were significantly (p=0.01) lower while plasma lathosterol was significantly higher (p=0.001) in patients with CF as compared to control subjects. Plasma cholesterol results were significantly lower (p=0.01) in CF patients. CONCLUSIONS: Our data suggest that the impaired intestinal absorption of exogenous sterols in patients with CF stimulates the endogenous synthesis of cholesterol, but the levels of total cholesterol in plasma remain lower. This may be due to the CFTR dysfunction that reduces cholesterol blood excretion causing the accumulation of cholesterol in liver cells and in other tissues contributing to trigger CF chronic inflammation.

Reduced caveolin-1 promotes hyperinflammation due to abnormal heme oxygenase-1 localization in lipopolysaccharide-challenged macrophages with dysfunctional cystic fibrosis transmembrane conductance regulator.

We have previously reported that TLR4 signaling is increased in LPS-stimulated cystic fibrosis (CF) macrophages (MΦs), contributing to the robust production of proinflammatory cytokines. The heme oxygenase-1 (HO-1)/CO pathway modulates cellular redox status, inflammatory responses, and cell survival. The HO-1 enzyme, together with the scaffold protein caveolin 1 (CAV-1), also acts as a negative regulator of TLR4 signaling in MΦs. In this study, we demonstrate that in LPS-challenged CF MΦs, HO-1 does not compartmentalize normally to the cell surface and instead accumulates intracellularly. The abnormal HO-1 localization in CF MΦs in response to LPS is due to decreased CAV-1 expression, which is controlled by the cellular oxidative state, and is required for HO-1 delivery to the cell surface. Overexpression of HO-1 or stimulating the pathway with CO-releasing molecules enhances CAV-1 expression in CF MΦs, suggesting a positive-feed forward loop between HO-1/CO induction and CAV-1 expression. These manipulations re-established HO-1 and CAV-1 cell surface localization in CF MΦs. Consistent with restoration of HO-1/CAV-1-negative regulation of TLR4 signaling, genetic or pharmacological (CO-releasing molecule 2) induced enhancement of this pathway decreased the inflammatory response of CF MΦs and CF mice treated with LPS. In conclusion, our results demonstrate that the counterregulatory HO-1/CO pathway, which is critical in balancing and limiting the inflammatory response, is defective in CF MΦs through a CAV-1-dependent mechanism, exacerbating the CF MΦ response to LPS. This pathway could be a potential target for therapeutic intervention for CF lung disease.

Identification of Inquilinus limosus in cystic fibrosis: a first report in Italy.

Cystic fibrosis is a genetic disorder associated with a polymicrobial lung infection where classical pathogens and newly identified bacteria may interact. Inquilinus limosus is an a-proteobacterium recently isolated in the airways of cystic fibrosis patient. We report the first case in Italy of I.limosus isolation from the sputum sample of a cystic fibrosis patient. The patient is a 20-years-old man with cystic fibrosis, regularly attending the Regional Care Center for Cystic Fibrosis at the Federico II University Hospital of Naples. Microbiological culture methods detected a mu- coid gram negative bacillus in the patient's sputum sample. The isolate exhibited a distinct antimicrobial suscep- tibility profile with a high MIC for several drugs. The MALDI-TOF mass spectrometry analysis indicated the bac- terium isolated as I. limosus, confirmed by 16s rDNA sequence analysis. The described clinical case demonstrates how the bacterial biodiversity in the airways of cystic fibrosis patients is still underestimated. Cystic fibrosis lung represents an ecological niche suitable for growth of a wide variety of unusual bacteria not commonly associated with human diseases, such as I. limosus. Therefore further studies are needed to evaluate the epidemiology and clinical implications of I. limosus in the physiopathology of cystic fibrosis lung infection.

The Italian external quality assessment program for Cystic Fibrosis sweat chloride test: CFTR modulators and the impact of a new sweat test report form.

Background: The advent of CFTR modulators highlighted that the sweat test (ST) for CF can be used also as an outcome measure for the basic defect of CFTR. Despite the technological advances, ST still remains operator-dependent and its execution should be strongly paired with guidelines. In 2022, due to the advent of CFTR modulators, the Italian CF Society introduced a specific ST report. The aim of the present paper is to discuss the impact of this new report in the 2022-23 round of the Italian External Quality Assessment program for ST (I-EQA-SCT). Methods: The scheme of the I-EQA-SCT is prospective, enrolment is voluntary, the payment of a fee is required and results are shared through a web-facility. Assessment covers analysis, interpretation, and reporting of results. In the 2022-23 round, 2 out of the 3 mock clinical information referred to patients who started modulators. Results: Fourteen laboratories completed the 2022-23 I-EQA-SCT round. Three of them failed in the interpretation of results from these two mock cases and/or used a wrong report not consistent with the more recent Italian Sweat Test Recommendations. Conclusions: The overall results obtained from the laboratories involved in the I-EQA-SCT program clearly showed that the laboratories' qualitative and quantitative performance improved significantly. Results emerged from this round highlighted an issue in the report form used for monitoring patients on CFTR modulator therapy thus stressing the importance of these programs in improving both the performance of lab services and ameliorating the sweat test recommendations.

A longitudinal study of glucose tolerance in cystic fibrosis: the central role of beta cell functional mass.

CONTEXT: The pathophysiological mechanisms underlying the natural history of glucose intolerance and its fluctuations in subjects with cystic fibrosis (CF) are still unclear. OBJECTIVE: To investigate the relationship between longitudinal changes in glucose tolerance and concomitant changes in the main parameters of insulin secretion/metabolism/action determining glucose regulation in CF subjects. METHODS: Insulin sensitivity and glucose-stimulated insulin secretion (GSIS, a biomarker of beta cell functional mass), as estimated by the Oral Glucose Sensitivity Index (OGIS) and by a sophisticated mathematical model, respectively, and insulin clearance were assessed in 127 CF subjects, aged 10-25 years, who underwent two OGTT tests over at least 1-year follow-up period. Subjects were classified a posteriori as regressors (improved glucose tolerance), stable, or progressors (worsened glucose tolerance). The interplay between beta cell compensatory action and insulin sensitivity over time was analyzed by vector plots of insulin clearance adjusted GSIS (PCadj) versus OGIS. RESULTS: OGIS decreased in progressors and stable. Insulin clearance decreased in both regressors and progressors. GSIS (beta cell functional mass) improved in regressors and worsened in progressors, whereas it did not change in stable. Vector plot analysis confirmed that glucose regulation changed differently in each group. Multinomial logistic regression analysis showed that baseline glucose tolerance and GSIS changes were the only significant predictors of the changes in glucose tolerance (p<0.02, R2Nagelkerke=0.55), whereas age, gender, z-BMI, CF genotypes, and baseline PCadj were not. CONCLUSIONS: In CF subjects, changes in beta cell functional mass are associated with favorable or detrimental changes of glucose tolerance over time.

Pseudo-Bartter syndrome in infant with cystic fibrosis screen positive, inconclusive diagnosis: A case report.

The introduction of newborn screening for cystic fibrosis (CF) increased diagnosis of cystic fibrosis screen positive inconclusive diagnosis (CFSPID). We described the case of a 12-month-old boy with CFSPID who, during summer, presented Pseudo-Bartter syndrome with no diagnostic criteria for CF.

The Role of Bronchoscopy in the Management of Children With Cystic Fibrosis.

BACKGROUND: Currently, no consensus guidelines recommend routine bronchoscopy procedure in cystic fibrosis (CF), as no evidence is available concerning its use as either a diagnostic or therapeutic tool. Its efficacy is controversial, and no randomized controlled prospective trials are available to check its effectiveness. The aims of the present study were to evaluate the effectiveness of bronchoscopy as a diagnostic/therapeutic tool in CF children and adolescents; and to verify the effect of serial bronchoscopy on lung disease progression in subjects with CF not responding to a single procedure. METHODS: Data of patients who received bronchoscopy at 2 Italian CF centers were collected. Bronchoalveolar lavage was performed during the procedure including airway clearance with mucolytics, inhaled antibiotics, and/or surfactant instillation. RESULTS: A total of 16 patients in center 1 and 17 in center 2 underwent, respectively, 28 and 23 bronchoscopic procedure in the study period. Five patients in each center underwent >1 procedure. All procedures were generally well tolerated. No patient required admission to the pediatric intensive therapy unit. In 19.6% of bronchoalveolar lavages, growth of Aspergillus fumigatus was evident, although not detected by sputum analyses. After the procedure, an increase in mean percent predicted forced expiratory volume in the 1 second >10% was observed, and a significant decrease in pulmonary exacerbations yearly was evident. CONCLUSION: Based on the results, we suggest bronchoscopy is not to be considered an obsolete tool, and it remains useful in CF management, although in selected cases. We encourage to support longitudinal observational studies to standardize the procedure, focusing on the choice of drugs to be instilled, modalities and timing of serial bronchoscopy and subsequent follow-up in selected severe clinical conditions.

The STING/TBK1/IRF3/IFN type I pathway is defective in cystic fibrosis.

Cystic fibrosis (CF) is a rare autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The most common mutation is F508del-CFTR (ΔF) which leads the encoded ion channel towards misfolding and premature degradation. The disease is characterized by chronic bronchopulmonary obstruction, inflammation and airways colonization by bacteria, which are the major cause of morbidity and mortality. The STING pathway is the main signaling route activated in the presence of both self and pathogen DNA, leading to Type I Interferon (IFN I) production and the innate immune response. In this study, we show for the first time the relationship existing in CF between resistant and recurrent opportunistic infections by Pseudomonas aeruginosa and the innate immunity impairment. We demonstrate through ex vivo and in vivo experiments that the pathway is inadequately activated in ΔF condition and the use of direct STING agonists, as 2',3'-cyclic GMP-AMP (2', 3' cGAMP), is able to restore the immune response against bacterial colonization. Indeed, upon treatment with the STING pathway agonists, we found a reduction of colony forming units (CFUs) consequent to IFN-ß enhanced production in Pseudomonas aeruginosa infected bone marrow derived macrophages and lung tissues from mice affected by Cystic Fibrosis. Importantly, we also verified that the impairment detected in the primary PBMCs obtained from ΔF patients can be corrected by 2', 3' cGAMP. Our work indicates that the cGAS/STING pathway integrity is crucial in the Cystic Fibrosis response against pathogens and that the restoration of the pathway by 2', 3' cGAMP could be exploited as a possible new target for the symptomatic treatment of the disease.

NMR spectroscopy metabolomic profiling of exhaled breath condensate in patients with stable and unstable cystic fibrosis.

BACKGROUND: Metabolomics could provide new insights into the pathophysiology of cystic fibrosis (CF) by identifying profiles of endogenous metabolites. OBJECTIVES: To investigate whether metabolomics of exhaled breath condensate could discriminate between patients with unstable CF, stable CF and healthy subjects, and whether selected metabolites were responsible for between-group differences. METHODS: Twenty-nine patients with stable CF, 24 with unstable CF and 31 healthy subjects (age 9-24 years) participated in a cross-sectional study. Metabolomics was performed with high-resolution nuclear magnetic resonance spectroscopy. Partial least squares-discriminant analysis was used as classifier. The results were validated in a second independent study. RESULTS: Intraclass correlation coefficients for between-day and technical repeatability were 0.93 and 0.96, respectively. Bland-Altman analysis showed good within-day repeatability. Correct classification rate of CF (n=53) vs. healthy subjects (n=31) was 96% (R2=0.84; Q2=0.79). Model validation with a testing sample set obtained from subjects not included in the primary analysis (23 CF and 25 healthy subjects) showed a sensitivity of 91% and a specificity of 96%. The classification rate of stable CF (n=29) vs. unstable CF patients (n=24) was 95% (R2=0.82; Q2=0.78). Model external validation in 14 patients with stable CF and 16 with unstable CF showed a sensitivity of 86% and a specificity of 94%. Ethanol, acetate, 2-propanol and acetone were most discriminant between patients with CF and healthy subjects, whereas acetate, ethanol, 2-propanol and methanol were the most important metabolites for discriminating between patients with stable and unstable CF. CONCLUSIONS: Nuclear magnetic resonance spectroscopy of exhaled breath condensate is reproducible, discriminates patients with CF from healthy subjects and patients with unstable CF from those with stable CF, and identifies the metabolites responsible for between-group differences.