J Cyst Fibros. 2021 Dec 20:S1569-1993(21)02156-1. doi: 10.1016/j.jcf.2021.11.015. Online ahead of print.

ABSTRACT

BACKGROUND: Improved survival of children with CF has increased our need to understand the relevance of cystic fibrosis-associated liver disease (CFLD). We assessed the impact of liver disease and disease severity on the survival of children with cystic fibrosis.

METHODS: A real life, single center cohort study with 27 years follow up was conducted. Mild CFLD was diagnosed as children with abnormal serum liver function tests and abnormal ultrasound. Advanced CFLD was established by detection of cirrhosis or portal hypertension. A directed acyclic graph, Kaplan-Meier (KM) and Cox regression analysis were used to model survival.

RESULTS: 290 patients were enrolled, 48 (16.5%) had mild CFLD and 55 (19%) had advanced CFLD. Ten children with advanced CFLD and 1 with mild CFLD died. Based on the KM analysis, the mean (SE) overall survival age of all CF children was 29.1 years (0.50). The mean (SE) survival among females with advanced CFLD was 24.7 years (1.58) compared to 30.4 years (0.66) for females without advanced CFLD (p = 0.0027). Advanced CFLD was a predictor of decreased survival when adjusted for sex and diabetes (HR 2.54, 95%CI 1.05-6.15, p = 0.039). Mild CFLD was not associated with decreased survival. The effect of advanced CFLD on survival was mainly borne by females (HR = 6.37, 95%CI 1.62-25.06 vs. males, HR = 1.00, 95%CI 0.25-4.01).

CONCLUSION: Advanced but not mild CFLD was associated with an increased risk of death when adjusted for sex and diabetes, and resulted in premature death in females with cystic fibrosis by approximately 6 years.

PMID:34949555 | DOI:10.1016/j.jcf.2021.11.015

Int J Mol Sci. 2021 Dec 11;22(24):13331. doi: 10.3390/ijms222413331.

ABSTRACT

Shwachman-Diamond syndrome (SDS) is a rare autosomal recessive disorder characterized by bone marrow failure, exocrine pancreatic insufficiency, and skeletal abnormalities, caused by loss-of-function mutations in the SBDS gene, a factor involved in ribosome biogenesis. By analyzing osteoblasts from SDS patients (SDS-OBs), we show that SDS-OBs displayed reduced SBDS gene expression and reduced/undetectable SBDS protein compared to osteoblasts from healthy subjects (H-OBs). SDS-OBs cultured in an osteogenic medium displayed a lower mineralization capacity compared to H-OBs. Whole transcriptome analysis showed significant differences in the gene expression of SDS-OBs vs. H-OBs, particularly in the ossification pathway. SDS-OBs expressed lower levels of the main genes responsible for osteoblastogenesis. Of all downregulated genes, Western blot analyses confirmed lower levels of alkaline phosphatase and collagen type I in SDS-OBs than in H-OBs. Interestingly, SDS-OBs showed higher protein levels of p53, an inhibitor of osteogenesis, compared to H-OBs. Silencing of Tp53 was associated with higher collagen type I and alkaline phosphatase protein levels and an increase in SDS-OB mineralization capacity. In conclusion, our results show that the reduced capacity of SDS-OBs to mineralize is mediated, at least in part, by the high levels of p53 and highlight an important role of SBDS in osteoblast functions.

PMID:34948128 | DOI:10.3390/ijms222413331

Int J Mol Sci. 2021 Dec 10;22(24):13312. doi: 10.3390/ijms222413312.

ABSTRACT

Environment-sensitive fluorophores are very valuable tools in the study of molecular and cellular processes. When used to label proteins and peptides, they allow for the monitoring of even small variations in the local microenvironment, thus acting as reporters of conformational variations and binding events. Luciferin and aminoluciferin, well known substrates of firefly luciferase, are environment-sensitive fluorophores with unusual and still-unexploited properties. Both fluorophores show strong solvatochromism. Moreover, luciferin fluorescence is influenced by pH and water abundance. These features allow to detect local variations of pH, solvent polarity and local water concentration, even when they occur simultaneously, by analyzing excitation and emission spectra. Here, we describe the characterization of (amino)luciferin-labeled derivatives of four bioactive peptides: the antimicrobial peptides GKY20 and ApoBL, the antitumor peptide p53pAnt and the integrin-binding peptide RGD. The two probes allowed for the study of the interaction of the peptides with model membranes, SDS micelles, lipopolysaccharide micelles and Escherichia coli cells. Kd values and binding stoichiometries for lipopolysaccharide were also determined. Aminoluciferin also proved to be very well-suited to confocal laser scanning microscopy. Overall, the characterization of the labeled peptides demonstrates that luciferin and aminoluciferin are previously neglected environment-sensitive labels with widespread potential applications in the study of proteins and peptides.

PMID:34948103 | DOI:10.3390/ijms222413312

Int J Mol Sci. 2021 Dec 7;22(24):13196. doi: 10.3390/ijms222413196.

ABSTRACT

Remarkable progress in CFTR research has led to the therapeutic development of modulators that rescue the basic defect in cystic fibrosis. There is continuous interest in studying CFTR molecular disease mechanisms as not all cystic fibrosis patients have a therapeutic option available. Addressing the basis of the problem by comprehensively understanding the critical molecular associations of CFTR interactions remains key. With the availability of CFTR modulators, there is interest in comprehending which interactions are critical to rescue CFTR and which are altered by modulators or CFTR mutations. Here, the current knowledge on interactions that govern CFTR folding, processing, and stability is summarized. Furthermore, we describe protein complexes and signal pathways that modulate the CFTR function. Primary epithelial cells display a spatial control of the CFTR interactions and have become a common system for preclinical and personalized medicine studies. Strikingly, the novel roles of CFTR in development and differentiation have been recently uncovered and it has been revealed that specific CFTR gene interactions also play an important role in transcriptional regulation. For a comprehensive understanding of the molecular environment of CFTR, it is important to consider CFTR mutation-dependent interactions as well as factors affecting the CFTR interactome on the cell type, tissue-specific, and transcriptional levels.

PMID:34947992 | DOI:10.3390/ijms222413196

Microorganisms. 2021 Dec 16;9(12):2604. doi: 10.3390/microorganisms9122604.

ABSTRACT

Burkholderia cepacia complex (BCC) is a significant pathogen causing respiratory disease in individuals with cystic fibrosis (CF). Diagnosis is typically achieved by isolation of BCC on selective culture media following culture of sputum or other respiratory samples. The aim of this study was to compare the efficacy of three commercially available selective media for the isolation of BCC. The three media comprised Burkholderia cepacia selective agar (BCSA; bioMérieux), BD Cepacia medium (BD: Becton-Dickinson) and MAST Cepacia medium (MAST laboratories). Each medium was challenged with 270 respiratory samples from individuals with CF as well as an international collection of BCC (n = 26) and 14 other isolates of Burkholderia species at a range of inocula. The international collection was also used to artificially "spike" 26 respiratory samples. From a total of 34 respiratory samples containing BCC, 97% were recovered on BD and 94% were detected on MAST and BCSA. All three media were effective for isolation of BCC. BCSA was much more selective than the other two media (p < 0.0001) meaning that fewer isolates required processing to exclude the presence of BCC.

PMID:34946206 | DOI:10.3390/microorganisms9122604

Microorganisms. 2021 Nov 30;9(12):2473. doi: 10.3390/microorganisms9122473.

ABSTRACT

Bacteria belonging to the genus Achromobacter are increasingly isolated from respiratory samples of people with cystic fibrosis (PWCF). The management of this multidrug-resistant genus is challenging and characterised by a lack of international recommendations, therapeutic guidelines and data concerning antibiotic susceptibility, especially concerning the newer antibiotics. The objective of this study was to describe the antibiotic susceptibility of Achromobacter isolates from PWCF, including susceptibility to new antibiotics. The minimum inhibitory concentrations (MICs) of 22 antibiotics were determined for a panel of 23 Achromobacter isolates from 19 respiratory samples of PWCF. Two microdilution MIC plates were used: EUMDROXF® plate (Sensititre) and Micronaut-S Pseudomonas MIC® plate (Merlin) and completed by a third method if necessary (E-test® or UMIC®). Among usual antimicrobial agents, the most active was imipenem (70% susceptibility). Trimethoprim-sulfamethoxazole, piperacillin and tigecycline (65%, 56% and 52% susceptibility, respectively) were still useful for the treatment of Achromobacter infections. Among new therapeutic options, β-lactams combined with a β-lactamase-inhibitor did not bring benefits compared to β-lactam alone. On the other hand, cefiderocol appeared as a promising therapeutic alternative for managing Achromobacter infections in PWCF. This study provides the first results on the susceptibility of clinical Achromobacter isolates concerning new antibiotics. More microbiological and clinical data are required to establish the optimal treatment of Achromobacter infections.

PMID:34946075 | DOI:10.3390/microorganisms9122473

J Pers Med. 2021 Dec 16;11(12):1376. doi: 10.3390/jpm11121376.

ABSTRACT

The clinical response to cystic fibrosis transmembrane conductance regulator (CFTR) modulators is variable within people with cystic fibrosis (pwCF) homozygous for the F508del mutation. The prediction of clinical effect in individual patients would be useful to target therapy to those who would benefit from it. A multicenter observational cohort study was conducted including 97 pwCF (F508del/F508del), who started lumacaftor/ivacaftor (LUM/IVA) treatment before June 2018. In order to assess the associations of individual in vivo and in vitro biomarkers with clinical outcomes, we collected clinical data regarding sex, age, and sweat chloride concentration (SwCl) at baseline and after six months of LUM/IVA; the percent predicted forced expiratory volume in 1 s (ppFEV1) and the number of pulmonary exacerbations (PEx) during the three years before up to three years after modulator initiation; and the forskolin-induced swelling (FIS) responses to LUM/IVA, quantified in intestinal organoids. On a group level, the results showed an acute change in ppFEV1 after LUM/IVA initiation (2.34%, 95% CI 0.85-3.82, p = 0.003), but no significant change in annual ppFEV1 decline in the three years after LUM/IVA compared to the three years before (change: 0.11% per year, 95%CI: -1.94-2.19, p = 0.913). Neither of these two outcomes was associated with any of the candidate predictors on an individual level. The median number of pulmonary exacerbations (PEx) per patient year did not significantly change in the three years after LUM/IVA compared to the years before (median: 0.33/patient year, IQR: 0-0.67 before vs. median: 0/patient year, IQR: 0-0.67 after p = 0. 268). The PEx rate after modulator initiation was associated with the PEx rate before (IRR: 2.26, 95%CI: 1.67-3.08, p < 0.001), with sex (males vs. females IRR: 0.36, 95%CI: 0.21-0.63, p = 0.001) and with sweat chloride concentration (SwCl) at baseline (IRR: 0.96, 95%CI: 0.94-0.98, p = 0.001). The change in SwCl was also significant (-22.9 mmol/L (95%CI: -27.1--18.8, p < 0.001) and was associated with SwCl at baseline (-0.64, 95%CI: -0.90--0.37, p < 0.001) and with sex (males vs. females 8.32, 95%CI: 1.82-14.82, p = 0.013). In conclusion, ppFEV1 decline after CFTR modulator initiation remains difficult to predict in individual patients in a real-world setting, with limited effectiveness for double CFTR modulator therapies. The PEx rate prior to CFTR modulator treatment initiation, sex and SwCl at baseline could be potential predictors of long-term PEx rate and of changes in SwCl after modulator initiation.

PMID:34945848 | DOI:10.3390/jpm11121376

J Pers Med. 2021 Dec 12;11(12):1353. doi: 10.3390/jpm11121353.

ABSTRACT

Cystic fibrosis (CF) is a devastating genetic infant-onset disease [...].

PMID:34945826 | DOI:10.3390/jpm11121353

J Clin Med. 2021 Dec 18;10(24):5955. doi: 10.3390/jcm10245955.

ABSTRACT

A number of studies have highlighted important alterations of the lipid profile in COVID-19 patients. Besides the well-known atheroprotective function, HDL displays anti-inflammatory, anti-oxidative, and anti-infectious properties. The aim of this retrospective study was to assess the HDL anti-inflammatory and antioxidant features, by evaluation of HDL-associated Serum amyloid A (SAA) enrichment and HDL-paraoxonase 1 (PON-1) activity, in a cohort of COVID-19 patients hospitalized at the Cardiorespiratory COVID-19 Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico of Milan. COVID-19 patients reached very low levels of HDL-c (mean ± SD: 27.1 ± 9.7 mg/dL) with a marked rise in TG (mean ± SD: 165.9 ± 62.5 mg/dL). Compared to matched-controls, SAA levels were significantly raised in COVID-19 patients at admission. There were no significant differences in the SAA amount between 83 alive and 22 dead patients for all-cause in-hospital mortality. Similar findings were reached in the case of PON-1 activity, with no differences between alive and dead patients for all-cause in-hospital mortality. In conclusion, although not related to the prediction of in-hospital mortality, reduction in HDL-c and the enrichment of SAA in HDL are a mirror of SARS-CoV-2 positivity even at the very early stages of the infection.

PMID:34945250 | DOI:10.3390/jcm10245955

J Clin Med. 2021 Dec 13;10(24):5821. doi: 10.3390/jcm10245821.

ABSTRACT

Cystic fibrosis (CF) is a monogenic autosomal recessive disease caused by cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. CF is characterized by a high phenotypic variability present even in patients with the same genotype. This is due to the intervention of modifier genes that interact with both the CFTR gene and environmental factors. The purpose of this review is to highlight the role of non-CFTR genetic factors (modifier genes) that contribute to phenotypic variability in CF. We analyzed literature data starting with candidate gene studies and continuing with extensive studies, such as genome-wide association studies (GWAS) and whole exome sequencing (WES). The results of both types of studies revealed that the number of modifier genes in CF patients is impressive. Their identification offers a new perspective on the pathophysiological mechanisms of the disease, paving the way for the understanding of other genetic disorders. In conclusion, in the future, genetic analysis, such as GWAS and WES, should be performed routinely. A challenge for future research is to integrate their results in the process of developing new classes of drugs, with a goal to improve the prognosis, increase life expectancy, and enhance quality of life among CF patients.

PMID:34945117 | DOI:10.3390/jcm10245821

J Clin Med. 2021 Dec 10;10(24):5779. doi: 10.3390/jcm10245779.

ABSTRACT

Exocrine pancreatic insufficiency (EPI), an important cause of maldigestion and malnutrition, results from primary pancreatic disease or is secondary to impaired exocrine pancreatic function. Although chronic pancreatitis is the most common cause of EPI, several additional causes exist. These include pancreatic tumors, pancreatic resection procedures, and cystic fibrosis. Other diseases and conditions, such as diabetes mellitus, celiac disease, inflammatory bowel disease, and advanced patient age, have also been shown to be associated with EPI, but the exact etiology of EPI has not been clearly elucidated in these cases. The causes of EPI can be divided into loss of pancreatic parenchyma, inhibition or inactivation of pancreatic secretion, and postcibal pancreatic asynchrony. Pancreatic enzyme replacement therapy (PERT) is indicated for the conditions described above presenting with clinically clear steatorrhea, weight loss, or symptoms related to maldigestion and malabsorption. This review summarizes the current literature concerning those etiologies of EPI less common than chronic pancreatitis, the pathophysiology of the mechanisms of EPI associated with each diagnosis, and treatment recommendations.

PMID:34945075 | DOI:10.3390/jcm10245779

Biomedicines. 2021 Nov 29;9(12):1788. doi: 10.3390/biomedicines9121788.

ABSTRACT

Respiratory infections by bacteria of the Burkholderia cepacia complex (Bcc) remain a life threat to cystic fibrosis (CF) patients, due to the faster lung function decline and the absence of effective eradication strategies. Immunotherapies are regarded as an attractive alternative to control and reduce the damages caused by these infections. In this work, we report the cloning and functional characterization of the OmpA-like BCAL2645 protein, previously identified and found to be immunoreactive against sera from CF patients with a record of Bcc infections. The BCAL2645 protein is shown to play a role in biofilm formation, adherence to mucins and invasion of human lung epithelial cells. The expression of the BCAL2645 protein was found to be increased in culture medium, mimicking the lungs of CF patients and microaerophilic conditions characteristic of the CF lung. Moreover, a polyclonal antibody raised against BCAL2645 was found to inhibit, by about 75 and 85%, the ability of B. cenocepacia K56-2 to bind and invade in vitro CFBE41o- human bronchial epithelial cells. These results highlight the potential of anti-BCAL2645 antibodies for the development of passive immunization therapies to protect CF patients against Bcc infections.

PMID:34944603 | DOI:10.3390/biomedicines9121788

Cells. 2021 Dec 20;10(12):3603. doi: 10.3390/cells10123603.

ABSTRACT

The respiratory epithelium represents the first chemical, immune, and physical barrier against inhaled noxious materials, particularly pathogens in cystic fibrosis. Local mucus thickening, altered mucociliary clearance, and reduced pH due to CFTR protein dysfunction favor bacterial overgrowth and excessive inflammation. We aimed in this review to summarize respiratory mucosal alterations within the epithelium and current knowledge on local immunity linked to immunoglobulin A in patients with cystic fibrosis.

PMID:34944110 | DOI:10.3390/cells10123603

Cells. 2021 Dec 4;10(12):3419. doi: 10.3390/cells10123419.

ABSTRACT

Induced Pluripotent Stem Cells (iPSCs) can be differentiated into epithelial organoids that recapitulate the relevant context for CFTR and enable testing of therapies targeting Cystic Fibrosis (CF)-causing mutant proteins. However, to date, CF-iPSC-derived organoids have only been used to study pharmacological modulation of mutant CFTR channel activity and not the activity of other disease-relevant membrane protein constituents. In the current work, we describe a high-throughput, fluorescence-based assay of CFTR channel activity in iPSC-derived intestinal organoids and describe how this method can be adapted to study other apical membrane proteins. Specifically, we show how this assay can be employed to study CFTR and ENaC channels and an electrogenic acid transporter in the same iPSC-derived intestinal tissue. This phenotypic platform promises to expand CF therapy discovery to include strategies that target multiple determinants of epithelial fluid transport.

PMID:34943927 | DOI:10.3390/cells10123419

Cells. 2021 Dec 1;10(12):3380. doi: 10.3390/cells10123380.

ABSTRACT

Cystic fibrosis in characterized by pulmonary bacterial colonization and hyperinflammation. Lymphocytes, monocytes/macrophages, neutrophils, and dendritic cells of patients with CF express functional CFTR and are directly affected by altered CFTR expression/function, impairing their ability to resolve infections and inflammation. However, the mechanism behind and the contribution of leukocytes in the pathogenesis of CF are still poorly characterized. The recent clinical introduction of specific CFTR modulators added an important tool not only for the clinical management of the disease but also to the investigation of the pathophysiological mechanisms related to CFTR dysfunction and dysregulated immunity. These drugs treat the basic defect in cystic fibrosis (CF) by increasing CFTR function with improvement of lung function and quality of life, and may improve clinical outcomes also by correcting the dysregulated immune function that characterizes CF. Measure of CFTR function, protein expression profiling and several omics methods were used to identify molecular changes in freshly isolated leukocytes of CF patients, highlighting two roles of leukocytes in CF: one more generally related to the mechanism(s) causing immune dysregulation in CF and unresolved inflammation, and another more applicative role, which identifies in myeloid cells, an important tool predictive of the therapeutic response of CF patients. In this review we will summarize available data on CFTR expression and function in leukocyte populations and will discuss potential clinical applications based on available data.

PMID:34943888 | DOI:10.3390/cells10123380

Antibiotics (Basel). 2021 Dec 14;10(12):1530. doi: 10.3390/antibiotics10121530.

ABSTRACT

Despite advances in antimicrobial therapy and even the advent of some effective vaccines, Pseudomonas aeruginosa (P. aeruginosa) remains a significant cause of infectious disease, primarily due to antibiotic resistance. Although P. aeruginosa is commonly treatable with readily available therapeutics, these therapies are not always efficacious, particularly for certain classes of patients (e.g., cystic fibrosis (CF)) and for drug-resistant strains. Multi-drug resistant P. aeruginosa infections are listed on both the CDC's and WHO's list of serious worldwide threats. This increasing emergence of drug resistance and prevalence of P. aeruginosa highlights the need to identify new therapeutic strategies. Combinations of monoclonal antibodies against different targets and epitopes have demonstrated synergistic efficacy with each other as well as in combination with antimicrobial agents typically used to treat these infections. Such a strategy has reduced the ability of infectious agents to develop resistance. This manuscript details the development of potential therapeutic targets for polyclonal antibody therapies to combat the emergence of multidrug-resistant P. aeruginosa infections. In particular, potential drug targets for combinational immunotherapy against P. aeruginosa are identified to combat current and future drug resistance.

PMID:34943742 | DOI:10.3390/antibiotics10121530

Antibiotics (Basel). 2021 Nov 24;10(12):1443. doi: 10.3390/antibiotics10121443.

ABSTRACT

Bacteria of the genus Burkholderia include pathogenic Burkholderia mallei, Burkholderia pseudomallei and the Burkholderia cepacia complex (Bcc). These Gram-negative pathogens have intrinsic drug resistance, which makes treatment of infections difficult. Bcc affects individuals with cystic fibrosis (CF) and the species B. cenocepacia is associated with one of the worst clinical outcomes. Following the repurposing of auranofin as an antibacterial against Gram-positive bacteria, we previously synthetized auranofin analogs with activity against Gram-negatives. In this work, we show that two auranofin analogs, MS-40S and MS-40, have antibiotic activity against Burkholderia clinical isolates. The compounds are bactericidal against B. cenocepacia and kill stationary-phase cells and persisters without selecting for multistep resistance. Caenorhabditis elegans and Galleria mellonella tolerated high concentrations of MS-40S and MS-40, demonstrating that these compounds have low toxicity in these model organisms. In summary, we show that MS-40 and MS-40S have antimicrobial properties that warrant further investigations to determine their therapeutic potential against Burkholderia infections.

PMID:34943654 | DOI:10.3390/antibiotics10121443

Children (Basel). 2021 Dec 14;8(12):1180. doi: 10.3390/children8121180.

ABSTRACT

Although many Clinical Practice Guidelines (CPGs) have been published for the care of patients with Cystic Fibrosis (CF), including a variety of nutrition recommendations, the quality of these CPGs has never been evaluated. The aim of this study was to compare, review, and critically appraise CPGs for the nutritional management of CF, throughout the lifespan. We searched PubMed, Guidelines International Network (GIN), ECRI Institute, and Guidelines Central for CPGs, with information on the nutritional management of CF. Retrieved CPGs were appraised by three independent reviewers, using the Appraisal of Guidelines, Research and Evaluation II (AGREE II) instrument and checklist. A total of 22 CPGs (seven solely nutrition oriented), by 14 different publishers, were retrieved. The Thoracic Society of Australia and New Zealand CPGs scored the highest overall quality (94.4%), while the Paediatric Gastroenterology Society/Dietitians Association of Australia CPGs had the lowest score (27.8%). Great variation in AGREE II domain-specific scores was observed in all CPGs, suggesting the existence of different strengths and weaknesses. Despite the availability of several CPGs, many appear outdated, lacking rigor, transparency, applicability, and efficiency, while incorporating bias. Considering that CPGs adherence is associated with better outcomes and the need for improving life expectancy in patients with CF, the development of CPGs of better quality is deemed necessary.

PMID:34943375 | DOI:10.3390/children8121180

Biology (Basel). 2021 Dec 20;10(12):1355. doi: 10.3390/biology10121355.

ABSTRACT

Treatment with PAN-PDE4 inhibitors has been shown to produce hypothermia in multiple species. Given the growing body of evidence that links nausea and emesis to disturbances in thermoregulation in mammals, we explored PDE4 inhibitor-induced hypothermia as a novel correlate of nausea in mice. Using knockout mice for each of the four PDE4 subtypes, we show that selective inactivation of individual PDE4 subtypes per se does not produce hypothermia, which must instead require the concurrent inactivation of multiple (at least two) PDE4 subtypes. These findings contrast with the role of PDE4s in shortening the duration of α2-adrenoceptor-dependent anesthesia, a behavioral surrogate previously used to assess the emetic potential of PDE4 inhibitors, which is exclusively affected by inactivation of PDE4D. These different outcomes are rooted in the distinct molecular mechanisms that drive these two paradigms; acting as a physiologic α2-adrenoceptor antagonist produces the effect of PDE4/PDE4D inactivation on the duration of α2-adrenoceptor-dependent anesthesia, but does not mediate the effect of PDE4 inhibitors on body temperature in mice. Taken together, our findings suggest that selective inhibition of any individual PDE4 subtype, including inhibition of PDE4D, may be free of nausea and emesis.

PMID:34943270 | DOI:10.3390/biology10121355

Antioxidants (Basel). 2021 Dec 2;10(12):1936. doi: 10.3390/antiox10121936.

ABSTRACT

Recurrent infection-inflammation cycles in cystic fibrosis (CF) patients generate a highly oxidative environment, leading to progressive destruction of the airway epithelia. The identification of novel modifier genes involved in oxidative stress susceptibility in the CF airways might contribute to devise new therapeutic approaches. We performed an unbiased genome-wide RNAi screen using a randomized siRNA library to identify oxidative stress modulators in CF airway epithelial cells. We monitored changes in cell viability after a lethal dose of hydrogen peroxide. Local similarity and protein-protein interaction network analyses uncovered siRNA target genes/pathways involved in oxidative stress. Further mining against public drug databases allowed identifying and validating commercially available drugs conferring oxidative stress resistance. Accordingly, a catalog of 167 siRNAs able to confer oxidative stress resistance in CF submucosal gland cells targeted 444 host genes and multiple circuitries involved in oxidative stress. The most significant processes were related to alternative splicing and cell communication, motility, and remodeling (impacting cilia structure/function, and cell guidance complexes). Other relevant pathways included DNA repair and PI3K/AKT/mTOR signaling. The mTOR inhibitor everolimus, the α1-adrenergic receptor antagonist doxazosin, and the Syk inhibitor fostamatinib significantly increased the viability of CF submucosal gland cells under strong oxidative stress pressure. Thus, novel therapeutic strategies to preserve airway cell integrity from the harsh oxidative milieu of CF airways could stem from a deep understanding of the complex consequences of oxidative stress at the molecular level, followed by a rational repurposing of existing "protective" drugs. This approach could also prove useful to other respiratory pathologies.

PMID:34943039 | DOI:10.3390/antiox10121936