Crystal Structure of Isoform CBd of the Basic Phospholipase A2 Subunit of Crotoxin: Description of the Structural Framework of CB for Interaction with Protein Targets.

Molecules. 2020 Nov 13;25(22):

Authors: Nemecz D, Ostrowski M, Ravatin M, Saul F, Faure G

Abstract
Crotoxin, from the venom of the South American rattlesnake Crotalus durissus terrificus, is a potent heterodimeric presynaptic β-neurotoxin that exists in individual snake venom as a mixture of isoforms of a basic phospholipase A2 (PLA2) subunit (CBa2, CBb, CBc, and CBd) and acidic subunit (CA1-4). Specific natural mutations in CB isoforms are implicated in functional differences between crotoxin isoforms. The three-dimensional structure of two individual CB isoforms (CBa2, CBc), and one isoform in a crotoxin (CA2CBb) complex, have been previously reported. This study concerns CBd, which by interaction with various protein targets exhibits many physiological or pharmacological functions. It binds with high affinity to presynaptic receptors showing neurotoxicity, but also interacts with human coagulation factor Xa (hFXa), exhibiting anticoagulant effect, and acts as a positive allosteric modulator and corrector of mutated chloride channel, cystic fibrosis transmembrane conductance regulator (CFTR), implicated in cystic fibrosis. Thus, CBd represents a novel family of agents that have potential in identifying new drug leads related to anticoagulant and anti-cystic fibrosis function. We determined here the X-ray structure of CBd and compare it with the three other natural isoforms of CB. The structural role of specific amino acid variations between CB isoforms are analyzed and the structural framework of CB for interaction with protein targets is described.

PMID: 33202772 [PubMed - in process]

NMR Profiling of Exhaled Breath Condensate Defines Different Metabolic Phenotypes of Non-Cystic Fibrosis Bronchiectasis.

Int J Mol Sci. 2020 Nov 14;21(22):

Authors: Paris D, Palomba L, Mirra V, Borrelli M, Corcione A, Santamaria F, Maniscalco M, Motta A

Abstract
Nuclear-magnetic-resonance (NMR) profiling of exhaled breath condensate (EBC) provides insights into the pathophysiology of bronchiectasis by identifying specific biomarkers. We evaluated whether NMR-based metabolomics discriminates the EBC-derived metabolic phenotypes ("metabotypes") of 41 patients with non-cystic fibrosis (nCF) bronchiectasis of various etiology [24 subjects with Primary Ciliary Dyskinesia (PCD); 17 patients with bronchiectasis not associated with PCD (nCF/nPCD)], who were compared to 17 healthy subjects (HS). NMR was used for EBC profiling, and Orthogonal Projections to Latent Structures with partial least-squares discriminant analysis (OPLS-DA) was used as a classifier. The results were validated by using the EBC from 17 PCD patients not included in the primary analysis. Different statistical models were built, which compared nCF/nPCD and HS, PCD and HS, all classes (nCF/nPCD-PCD-HS), and, finally, PCD and nCF/nPCD. In the PCD-nCF/nPCD model, four statistically significant metabolites were able to discriminate between the two groups, with only a minor reduction of the quality parameters. In particular, for nCF/nPCD, acetone/acetoin and methanol increased by 21% and 18%, respectively. In PCD patients, ethanol and lactate increased by 25% and 28%, respectively. They are all related to lung inflammation as methanol is found in the exhaled breath of lung cancer patients, acetone/acetoin produce toxic ROS that damage lung tissue in CF, and lactate is observed in acute inflammation. Interestingly, a high concentration of ethanol hampers cilia beating and can be associated with the genetic defect of PCD. Model validation with 17 PCD samples not included in the primary analysis correctly predicted all samples. Our results indicate that NMR of EBC discriminates nCF/nPCD and PCD bronchiectasis patients from HS, and patients with nCF/nPCD from those with PCD. The metabolites responsible for between-group separation identified specific metabotypes, which characterize bronchiectasis of a different etiology.

PMID: 33202684 [PubMed - in process]

Estimation of Proinflammatory Factors in the Saliva of Adult Patients with Cystic Fibrosis and Dental Caries.

Medicina (Kaunas). 2020 Nov 14;56(11):

Authors: Hildebrandt T, Zawilska A, Trzcionka A, Tanasiewicz M, Mazurek H, Świętochowska E

Abstract
Introduction: The available literature lacks data regarding the levels of resistin, lysozyme, lactoferrin, α-amylase activity, pH, and saliva buffer capacity, as well as oral health and hygiene in the group of adult patients with cystic fibrosis (CF). The aim of the research was to assess the selected saliva parameters in patients diagnosed with cystic fibrosis. Materials and methods: Examined group was composed of 40 patients diagnosed with CF, while the control group of 40 healthy individuals. Both groups underwent the same scheme of the assessment (DMT index, salivary pH, buffer capacity, analysis of total sialic acid, total protein estimation, lysozyme levels estimation, lactofferin levels measurement, α-amylase activity, estimation of the levels of resistin and TNF-α). Results: In the examined group, there were higher values of decayed teeth as well as values of sialic acid, total protein, lactoferrin, α-amylase, and TNF-α. However, mean lysozyme, and resistin levels, as well as pH and buffer capacity of the saliva, were lower. Conclusions: New diagnostic methods, including the evaluation of selected salivary biochemical parameters, may indicate the existence of factors predisposing to severe tooth decay in the study group. Appropriate preventive treatment to combat dental caries in adult patients with CF will significantly improve their comfort and life expectancy.

PMID: 33202617 [PubMed - in process]

Current Treatment Options for Cystic Fibrosis-Related Liver Disease.

Int J Mol Sci. 2020 Nov 14;21(22):

Authors: Staufer K

Abstract
Cystic Fibrosis-related liver disease (CFLD) has become a leading cause of morbidity and mortality in patients with Cystic Fibrosis (CF), and affects children and adults. The understanding of the pathogenesis of CFLD is key in order to develop efficacious treatments. However, it remains complex, and has not been clarified to the last. The search for a drug might be additionally complicated due to the diverse clinical picture and lack of a unified definition of CFLD. Although ursodeoxycholic acid has been used for decades, its efficacy in CFLD is controversial, and the potential of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators and targeted gene therapy in CFLD needs to be defined in the near future. This review focuses on the current knowledge on treatment strategies for CFLD based on pathomechanistic viewpoints.

PMID: 33202578 [PubMed - in process]

Gastroesophageal Reflux Disease and Need for Antireflux Surgery in Children with Cystic Fibrosis: A Systematic Review on Incidence, Surgical Complications, and Postoperative Outcomes.

Eur J Pediatr Surg. 2020 Nov 17;:

Authors: Ng J, Friedmacher F, Pao C, Charlesworth P

Abstract
INTRODUCTION:  Gastroesophageal reflux disease (GERD) is associated with accelerated decline in lung health in children with cystic fibrosis (CF). Thus, antireflux surgery (ARS) is offered to a selected CF cohort with refractory GERD, but outcomes remain poorly investigated. This study aimed to determine the incidence of GERD in children with CF and to evaluate complications and outcomes of ARS.
MATERIALS AND METHODS:  A systematic literature-based search was conducted using various online databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The number of GERD cases in pediatric CF cohorts who underwent diagnostic investigation(s) was recorded. Data on postoperative complications and outcomes (including symptoms, lung function, and nutritional status) following ARS were analyzed.
RESULTS:  Ten articles (n = 289 patients) met the defined inclusion criteria (51% male; age range, 0.5 month-36 years). The overall incidence of GERD was 46% (range, 19-81%), derived from seven studies (n = 212 patients). Four publications (n = 82 patients) reported on ARS due to uncontrolled GERD. All ARSs were Nissen fundoplication (majority with gastrostomy placement). Major postoperative complications occurred in 15 (18%) patients, two required redo-ARS. Median follow-up time was 2 years (range, 3 months-6 years); 59% showed symptom improvement, and pulmonary exacerbations and decline in lung function were reduced. Nutritional status mainly improved in milder CF cases. There were no deaths related to ARS.
CONCLUSION:  Approximately half of pediatric CF patients have GERD. Published data for children with CF are limited and heterogeneous in terms of GERD diagnosis and outcomes following ARS. However, ARS has shown to slow the deterioration of lung function in CF.

PMID: 33202431 [PubMed - as supplied by publisher]

Vitamin D Deficiency Is Associated with Increased Nontuberculous Mycobacteria Risk in Cystic Fibrosis.

Ann Am Thorac Soc. 2020 Nov 17;:

Authors: Richter WJ, Sun Y, Psoter KJ, Santos MN, Nguyen JA, Sidhaye A, Lechtzin N, Jennings MT, Cohen KA

PMID: 33202142 [PubMed - as supplied by publisher]

[Evidence-based treatment of cystic fibrosis].

Internist (Berl). 2020 Nov 17;:

Authors: Ringshausen FC, Hellmuth T, Dittrich AM

Abstract
Mucoviscidosis (cystic fibrosis [CF]) is the most common autosomal recessive inherited multisystem disease with fatal outcome. It is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which lead to a dysfunctional chloride channel and a defective CFTR protein. As a consequence, retention of insufficiently hydrated mucus affects multiple essential organs, mainly the lungs and airways, pancreas, liver, biliary tract and intestines. This leads to inflammation and infection, fibrosis and progressive tissue destruction. Respiratory failure is the major cause of mortality; however, in the no more than 30 years since the molecular characterization of the basic CFTR defect causing CF, tremendous success has been made with respect to the long-term prognosis of people with CF. This improvement in the prognosis was achieved by the cooperative spirit and networking of the very active and international CF research community and by establishing a multidisciplinary clinical CF team that implements the existing evidence in various aspects of standardized care together with the CF patient. This narrative review article presents the evidence in selected aspects of CF treatment, with special consideration of the most recent development of highly effective CFTR modulator treatment. This treatment will soon become available for more than 90% of the global CF patients and transform the pathophysiology as well as the course of disease towards a treatable chronic condition in internal medicine.

PMID: 33201261 [PubMed - as supplied by publisher]

ADIPS 2020 guideline for pre-existing diabetes and pregnancy.

Aust N Z J Obstet Gynaecol. 2020 Nov 16;:

Authors: Rudland VL, Price SAL, Hughes R, Barrett HL, Lagstrom J, Porter C, Britten FL, Glastras S, Fulcher I, Wein P, Simmons D, McIntyre HD, Callaway L

Abstract
This is the full version of the Australasian Diabetes in Pregnancy Society (ADIPS) 2020 guideline for pre-existing diabetes and pregnancy. The guideline encompasses the management of women with pre-existing type 1 diabetes and type 2 diabetes in relation to pregnancy, including preconception, antepartum, intrapartum and postpartum care. The management of women with monogenic diabetes or cystic fibrosis-related diabetes in relation to pregnancy is also discussed.

PMID: 33200400 [PubMed - as supplied by publisher]

Ultra-low-dose chest CT in adult patients with cystic fibrosis using a third-generation dual-source CT scanner.

Radiol Med. 2020 Nov 16;:

Authors: Tagliati C, Lanza C, Pieroni G, Amici L, Carotti M, Giuseppetti GM, Giovagnoni A

Abstract
INTRODUCTION: Chest computed tomography (CT) examinations are performed routinely in some cystic fibrosis (CF) centers in order to evaluate lung disease progression in CF patients. Continuous CT technological advancement in theory could allows a lower radiation exposure of CF patients during chest CT examinations without an image quality reduction, and this could become increasingly important over time in order to reduce the cumulative radiation dose effects given the continuous increase of CF patients predicted median survival.
OBJECTIVE: The aim of this study was to compare objective and subjective image quality and radiation dose between low-dose chest CT examinations performed in adult CF patients using a third-generation DSCT scanner and a 64-slices single-source CT (SSCT) scanner.
MATERIALS AND METHODS: Between January 2016 and August 2019, 81 CF patients underwent low-dose chest CT examinations using both a 64-slices SSCT scanner (2016-2017) and a third-generation DSCT scanner (2018-2019). Objective image noise standard deviation (INSD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), overall subjective image quality (OSIQ), subjective image noise (SIN), subjective evaluation of streaking artifacts (SA), movement artifacts (MA) and edge resolution (ER), dose-length product (DLP), volume computed tomography dose index (CTDIvol) and effective radiation dose (ERD) were compared between DSCT and SSCT examinations. DSCT examinations consisted in spiral inspiratory end expiratory acquisitions. SSCT examinations consisted in spiral inspiratory acquisitions and five axial expiratory ones.
RESULTS: DSCT protocol showed statistically significant lower spiral inspiratory phase mean DLP, CTDIvol and ERD than SSCT protocol, with a 25% DLP, CTDIvol and ERD reduction. DSCT protocol showed statistically significant higher overall (inspiratory and expiratory phases) mean DLP, CTDIvol and ERD than SSCT protocol, with a 40% DLP, CTDIvol and ERD increase. Objective image quality (INSD, SNR and CNR) and SIN differences were not statistically significant, but subjective evaluation of DSCT images showed statistically significant better OSIQ and ER, as well as statistically significant lower SA and MA with respect to SSCT images.
CONCLUSIONS: To our knowledge, this is the first study evaluating chest CT image quality and radiation dose in adult CF patients using a third-generation DSCT scanner, and it showed that technological advancements could be used in order to reduce radiation exposure of volumetric examinations. The spiral inspiratory dose reduction can be obtained with concomitant improvements in subjective image quality with comparable objective quality. This will probably allow a wider use of this imaging modality in order to assess bronchiectasis and will probably foster spiral expiratory acquisition for small airways disease evaluation.

PMID: 33200307 [PubMed - as supplied by publisher]

Rapidly progressive metastatic cholangiocarcinoma in a postpartum patient with cystic fibrosis: a case report.

BMC Pulm Med. 2020 Nov 16;20(1):298

Authors: Carson SW, Craven KE, Nauen D, Montemayor K, Yarchoan M, Burns WR, Merlo CA, West NE

Abstract
BACKGROUND: Cholangiocarcinoma is a rare gastrointestinal malignancy that arises within the intrahepatic, perihilar, and/or extrahepatic bile ducts. Individuals with cystic fibrosis are at increased risk for gastrointestinal malignancies. The most common gastrointestinal malignancy in cystic fibrosis is colon cancer, but other gastrointestinal malignancies also occur at greater rates than the general population.
CASE PRESENTATION: We present a case of a rapidly progressive metastatic intrahepatic cholangiocarcinoma in an individual with cystic fibrosis who was 5 months postpartum, incidentally found while undergoing a lung transplantation evaluation.
CONCLUSION: A heightened clinical awareness of gastrointestinal malignancies, beyond colon cancer, in individuals with cystic fibrosis is warranted. It remains unclear if pregnancy is an additional risk factor for gastrointestinal malignancies in cystic fibrosis.

PMID: 33198722 [PubMed - in process]

Non-Linear Pharmacokinetics of Oral Roscovitine (Seliciclib) in Cystic Fibrosis Patients Chronically Infected with Pseudomonas aeruginosa: A Study on Population Pharmacokinetics with Monte Carlo Simulations.

Pharmaceutics. 2020 Nov 12;12(11):

Authors: Leven C, Schutz S, Audrezet MP, Nowak E, Meijer L, Montier T

Abstract
Roscovitine (Seliciclib), a new protein kinase inhibitor, was administered orally to adult patients with cystic fibrosis for the first time in the ROSCO-CF trial, a dose-escalation, phase IIa, randomized, controlled trial. Extensive pharmacokinetic sampling was performed up to 12 h after the first oral dose. Roscovitine and its main metabolite M3 were quantified by liquid chromatography coupled with tandem mass spectrometry. The pharmacokinetics analyses were performed by non-linear mixed effects modelling. Monte Carlo simulations were performed to assess the impact of dose on the pharmacokinetics of oral roscovitine. Twenty-three patients received oral doses ranging from 200 to 800 mg of roscovitine and 138 data points were available for both roscovitine and M3 concentrations. The pharmacokinetics was best described by a two-compartment parent-metabolite model, with a complex saturable absorption process modelled as the sum of Gaussian inverse density functions. The Monte Carlo simulations showed a dose-dependent and saturable first-pass effect leading to pre-systemic formation of M3. The treatment with proton-pump inhibitors reduced the rate of absorption of oral roscovitine. The pharmacokinetics of oral roscovitine in adult patients with cystic fibrosis was non-linear and showed significant inter-individual variability. A repeat-dose study will be required to assess the inter-occasional variability of its pharmacokinetics.

PMID: 33198319 [PubMed]

Nebuliser performance and electrical voltage: implications for patients with chronic respiratory conditions travelling to low voltage (110 V) countries.

J Travel Med. 2020 Nov 16;:

Authors: Moore JE, Bell J, Millar BC

Abstract
Employment of incorrect mains voltage with jet nebulisers will result in marked reduction in output. Patients with chronic respiratory conditions who use nebulisers as important components of their care, should ensure that they are using the correct/compatible voltage with their nebuliser compressor to achieve optimal dosing of their aerosolised medications.

PMID: 33196084 [PubMed - as supplied by publisher]

Cystic Fibrosis Diagnosed Using Indigenously Wrapped Sweating Technique: First Large-Scale Study Reporting Socio-Demographic, Clinical, and Laboratory Features among the Children in Bangladesh A Lower Middle Income Country.

Glob Pediatr Health. 2020;7:2333794X20967585

Authors: Kabir AL, Roy S, Habib RB, Anwar KS, Mollah MAH, Amin R, Mridha AA, Majumder JU, Hossain MD, Haque N, Ahmed S, Chisti MJ

Abstract
Due to lack of robust data on childhood cystic fibrosis (CF) in Bangladesh we sought to evaluate their clinico-epidemiology. A cross-sectional observation was conducted adopting CF-foundation consensus-panel-diagnostic criteria in 3 tertiary-care-hospitals in Bangladesh from 2000 to 2017. Clinically suspected 95 CF-cases were subjected to sweat-chloride testing using locally-developed a fast, cheap and effective indigenously body-wrapped sweating technique measured by US-Easy Lyte-automated microprocessor-controlled analyzer marking ≥60 mmol/L as positive. Mean-age of CF-cases at disease-onset was 16.9 ± 26.6 months that significantly differed with age-at-diagnosis (P < .02). Pulmonary syndromes included chronic wet cough in 100%, respiratory distress in 90.5%, digital-clubbing in 78%, mucopurulent-sputum in 74%-cases, and crepitation in 82%. Radio-imaging revealed bronchiectasis in 60%, hyperinflation/peribronchial-thickening in 22% and, pan-sinusitis in 89%-cases. While 37% had history-of malabsorption, high-fecal-fat revealed in 53%-cases. Malnutrition prevailed as severe-underweight in 87%-cases and all CF-cases (100%) had high sweat-chloride (mean = 118 ± 53.34 mmol/L). Thus, children with pulmonary features coupled with severe malnutrition and associated radio-imaging bronchiectasis should be screened for CF with a fast, cheap and effective sweat test in resource poor settings.

PMID: 33195743 [PubMed]

Dehydrated patient without clinically evident cause: A case report.

World J Clin Cases. 2020 Oct 26;8(20):4838-4843

Authors: Palladino F, Fedele MC, Casertano M, Liguori L, Esposito T, Guarino S, Miraglia Del Giudice E, Marzuillo P

Abstract
BACKGROUND: Patients affected by cystic fibrosis can present with metabolic alkalosis such as Bartter's syndrome. In this case report we want to underline this differential diagnosis and we aimed focusing on the suspect of cystic fibrosis, also in case of a negative newborn screening.
CASE SUMMARY: In a hot August -with a mean environmental temperature of 36 °C- an 8-mo-old female patient presented with severe dehydration complicated by hypokalemic metabolic alkalosis, in absence of fever, diarrhea and vomiting. Differential diagnosis between cystic fibrosis and tubulopathies causing metabolic alkalosis (Bartter's Syndrome) was considered. We started intravenous rehydration with subsequent improvement of clinical conditions and serum electrolytes normalization. We diagnosed a mild form of cystic fibrosis (heterozygous mutations: G126D and F508del in the cystic fibrosis transmembrane conductance regulator gene). The trigger factor of this condition had been heat exposure.
CONCLUSION: When facing a patient with hypokalemic metabolic alkalosis, cystic fibrosis presenting with Pseudo-Bartter's syndrome should be considered in the differential diagnosis, even if the newborn screening was negative.

PMID: 33195651 [PubMed]

The Open Challenge of in vitro Modeling Complex and Multi-Microbial Communities in Three-Dimensional Niches.

Front Bioeng Biotechnol. 2020;8:539319

Authors: Oriano M, Zorzetto L, Guagliano G, Bertoglio F, van Uden S, Visai L, Petrini P

Abstract
The comprehension of the underlying mechanisms of the interactions within microbial communities represents a major challenge to be faced to control their outcome. Joint efforts of in vitro, in vivo and ecological models are crucial to controlling human health, including chronic infections. In a broader perspective, considering that polymicrobial communities are ubiquitous in nature, the understanding of these mechanisms is the groundwork to control and modulate bacterial response to any environmental condition. The reduction of the complex nature of communities of microorganisms to a single bacterial strain could not suffice to recapitulate the in vivo situation observed in mammals. Furthermore, some bacteria can adapt to various physiological or arduous environments embedding themselves in three-dimensional matrices, secluding from the external environment. Considering the increasing awareness that dynamic complex and dynamic population of microorganisms (microbiota), inhabiting different apparatuses, regulate different health states and protect against pathogen infections in a fragile and dynamic equilibrium, we underline the need to produce models to mimic the three-dimensional niches in which bacteria, and microorganisms in general, self-organize within a microbial consortium, strive and compete. This review mainly focuses, as a case study, to lung pathology-related dysbiosis and life-threatening diseases such as cystic fibrosis and bronchiectasis, where the co-presence of different bacteria and the altered 3D-environment, can be considered as worst-cases for chronic polymicrobial infections. We illustrate the state-of-art strategies used to study biofilms and bacterial niches in chronic infections, and multispecies ecological competition. Although far from the rendering of the 3D-environments and the polymicrobial nature of the infections, they represent the starting point to face their complexity. The increase of knowledge respect to the above aspects could positively affect the actual healthcare scenario. Indeed, infections are becoming a serious threat, due to the increasing bacterial resistance and the slow release of novel antibiotics on the market.

PMID: 33195112 [PubMed]

Current Approach in the Diagnosis and Management of Allergic Bronchopulmonary Aspergillosis in Children With Cystic Fibrosis.

Front Pediatr. 2020;8:582964

Authors: Sunman B, Ademhan Tural D, Ozsezen B, Emiralioglu N, Yalcin E, Özçelik U

Abstract
Allergic bronchopulmonary aspergillosis (ABPA) is a complex pulmonary disorder characterized by a hypersensitivity reaction to Aspergillus fumigatus, and almost always seen in patients with cystic fibrosis (CF) and asthma. Fungal hyphae leads to an ongoing inflammation in the airways that may result in bronchiectasis, fibrosis, and eventually loss of lung function. Despite the fact that ABPA is thought to be more prevalent in CF than in asthma, the literature on ABPA in CF is more limited. The diagnosis is challenging and may be delayed because it is made based on a combination of clinical features, and radiologic and immunologic findings. With clinical deterioration of a patient with CF, ABPA is important to be kept in mind because clinical manifestations mimic pulmonary exacerbations of CF. Early diagnosis and appropriate treatment are important in preventing complications related to ABPA. Treatment modalities involve the use of anti-inflammatory agents to suppress the immune hyperreactivity and the use of antifungal agents to reduce fungal burden. Recently, in an effort to treat refractory patients or to reduce adverse effects of steroids, other treatment options such as monoclonal antibodies have started to be used. Intensive research of these new agents in the treatment of children is being conducted to address insufficient data.

PMID: 33194914 [PubMed]

Synthesis of the Hydroxamate Siderophore N α-Methylcoprogen B in Scedosporium apiospermum Is Mediated by sidD Ortholog and Is Required for Virulence.

Front Cell Infect Microbiol. 2020;10:587909

Authors: Le Govic Y, Havlíček V, Capilla J, Luptáková D, Dumas D, Papon N, Le Gal S, Bouchara JP, Vandeputte P

Abstract
Scedosporium species rank second among the filamentous fungi capable to colonize chronically the respiratory tract of patients with cystic fibrosis (CF). Nevertheless, there is little information on the mechanisms underpinning their virulence. Iron acquisition is critical for the growth and pathogenesis of many bacterial and fungal genera that chronically inhabit the CF lungs. In a previous study, we showed the presence in the genome of Scedosporium apiospermum of several genes relevant for iron uptake, notably SAPIO_CDS2806, an ortholog of sidD, which drives the synthesis of the extracellular hydroxamate-type siderophore fusarinine C (FsC) and its derivative triacetylfusarinine C (TAFC) in Aspergillus fumigatus. Here, we demonstrate that Scedosporium apiospermum sidD gene is required for production of an excreted siderophore, namely, N α-methylcoprogen B, which also belongs to the hydroxamate family. Blockage of the synthesis of N α-methylcoprogen B by disruption of the sidD gene resulted in the lack of fungal growth under iron limiting conditions. Still, growth of ΔsidD mutants could be restored by supplementation of the culture medium with a culture filtrate from the parent strain, but not from the mutants. Furthermore, the use of xenosiderophores as the sole source of iron revealed that S. apiospermum can acquire the iron using the hydroxamate siderophores ferrichrome or ferrioxamine, i.e., independently of N α-methylcoprogen B production. Conversely, N α-methylcoprogen B is mandatory for iron acquisition from pyoverdine, a mixed catecholate-hydroxamate siderophore. Finally, the deletion of sidD resulted in the loss of virulence in a murine model of scedosporiosis. Our findings demonstrate that S. apiospermum sidD gene drives the synthesis of a unique extracellular, hydroxamate-type iron chelator, which is essential for fungal growth and virulence. This compound scavenges iron from pyoverdine, which might explain why S. apiospermum and Pseudomonas aeruginosa are rarely found simultaneously in the CF lungs.

PMID: 33194829 [PubMed - in process]

Evaluation of quorum-sensing inhibitory effects of extracts of three traditional medicine plants with known antibacterial properties.

New Microbes New Infect. 2020 Nov;38:100769

Authors: Moradi F, Hadi N, Bazargani A

Abstract
Today an alternative approach to control bacterial infections is the use of natural and traditional plant compounds to interfere with their quorum-sensing (QS) systems. In this study, antibacterial and anti-QS sensing activity of Syzygium aromaticum, Dionysia revoluta Boiss. and Eucalyptus camaldulensis Dehnh. were evaluated. These plants are local to the Middle East region and have since ancient times been used for their antibacterial activity. Plant compounds were extracted with n-hexane, methanol and 96% ethanol mixed solvent. Antibacterial activity of this herbal extracts against five Gram-negative and Gram-positive bacteria were assessed. The effective sub-minimum inhibitory concentration (MIC) of this extract on bacterial QS systems were investigated by a violacein quantification assay in the Chromobacterium violaceum CV026 biosensor strain, inhibition of exogenously QS signal molecules in Aeromonas veronii bv. Sobria strain BC88 and Pseudomonas aeruginosa isolated from a patient with cystic fibrosis in vitro. Results found that Syzygium aromaticum 0.39 to 0.048 mg/mL, Dionysia revoluta Boiss. 3.1 to 0.39 mg/mL and E. camaldulensis 0.78 to 0.097 mg/mL showed anti-QS activities by reducing the violacein formation depletion of QS signals produced in A. veronii and P. aeruginosa at sub-MICs. Regarding the anti-QS effects of these herbal extracts, their effective components may be candidates for use in combating bacterial infections at sub-MICs.

PMID: 33194208 [PubMed]

Impact of a Gap Junction Protein Alpha 4 Variant on Clinical Disease Phenotype in F508del Homozygous Patients With Cystic Fibrosis.

Front Genet. 2020;11:570403

Authors: Horn T, Ludwig M, Eickmeier O, Neerinex AH, Maitland-van der Zee AH, Smaczny C, Wagner TOF, Schubert R, Zielen S, Majoor C, Bos LD, Schmitt-Grohé S

Abstract
Background: Lung disease phenotype varies widely even in the F508del (homozygous) genotype. Leukocyte-driven inflammation is important for pulmonary disease pathogenesis in cystic fibrosis (CF). Blood cytokines correlate negatively with pulmonary function in F508del homozygous patients, and gap junction proteins (GJA) might be related to the influx of blood cells into the lung and influence disease course. We aimed to assess the relationship between GJA1/GJA4 genotypes and the clinical disease phenotype.
Methods: One-hundred-and-sixteen homozygous F508del patients (mean age 27 years, m/f 66/50) were recruited from the CF centers of Bonn, Frankfurt, and Amsterdam. Sequence analysis was performed for GJA1 and GJA4. The clinical disease course was assessed over 3 years using pulmonary function tests, body mass index, Pseudomonas aeruginosa colonization, diabetes mellitus, survival to end-stage lung disease, blood and sputum inflammatory markers.
Results: Sequence analysis revealed one clinically relevant single nucleotide polymorphism. In this GJA4 variant (rs41266431), homozygous G variant carriers (n = 84/116; 72.4%) had poorer pulmonary function (FVC% pred: mean 78/86, p < 0.040) and survival to end-stage lung disease was lower (p < 0.029). The frequency of P. aeruginosa colonization was not influenced by the genotype, but in those chronically colonized, those with the G/G genotype had reduced pulmonary function (FVC% pred: mean 67/80, p < 0.049). Serum interleukin-8 (median: 12.4/6.7 pg/ml, p < 0.052) and sputum leukocytes (2305/437.5 pg/ml, p < 0.025) were higher for the G/G genotype.
Conclusions: In carriers of the A allele (27.6%) the GJA4 variant is associated with significantly better protection against end-stage lung disease and superior pulmonary function test results in F508del homozygous patients. This SNP has the potential of a modifier gene for phenotyping severity of CF lung disease, in addition to the CFTR genotype.
Clinical Trial Registration: The study was registered with ClinicalTrials.gov, number NCT04242420, retrospectively on January 24th, 2020.

PMID: 33193670 [PubMed]

A SNARE protein Syntaxin 17 captures CFTR to potentiate autophagosomal clearance under stress.

FASEB J. 2020 Nov 15;:

Authors: Arora K, Liyanage P, Zhong Q, Naren AP

Abstract
Autophagy, a cellular stress response to starvation and bacterial infection, is executed by double-membrane-bound organelles called autophagosomes. Autophagosomes transfer cytosolic material to acidified lysosomes for degradation following soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE)-dependent fusion processes. Many of the autophagy-related disorders stem from defective end-step proteolysis inside lysosomes. The role of epithelial cystic fibrosis (CF) transmembrane conductance regulator (CFTR) chloride channel has been argued to be critical for efficient lysosomal clearance; however, its context to autophagic clearance and the underlying mechanism is poorly defined. Here, we report that syntaxin17 (Stx17), an autophagic SNARE protein interacts with CFTR under nutritional stress and bacterial infection and incorporates it into mature autophagosomes to mediate an efficient lysosomal clearance. Lack of CFTR function and Stx17 and loss of CFTR-Stx17 interaction impairs bacterial clearance. We discover a specialized role of the Stx17-CFTR protein complex that is critical to prevent defective autophagy as has been the reported scenario in CF airway epithelial cells, infectious diseases, and lysosomal clearance disorders.

PMID: 33191543 [PubMed - as supplied by publisher]