Biotechnol Adv. 2021 Oct 27:107862. doi: 10.1016/j.biotechadv.2021.107862. Online ahead of print.

ABSTRACT

One of the hallmarks of the environmental bacterium Pseudomonas aeruginosa is its excellent ecological flexibility, which can thrive in diverse ecological niches. In different ecosystems, P. aeruginosa may use different strategies to survive, such as forming biofilms in crude oil environment, converting to mucoid phenotype in the cystic fibrosis (CF) lung, or becoming persisters when treated with antibiotics. Rugose small colony variants (RSCVs) are the adaptive mutants of P. aeruginosa, which can be frequently isolated from chronic infections. During the past years, there has been a renewed interest in using P. aeruginosa as a model organism to investigate the RSCVs formation, persistence and pathogenesis, as RSCVs represent a hyper-biofilm formation, high adaptability, high-tolerance sub-population in biofilms. This review will briefly summarize recent advances regarding the phenotypic, genetic and host interaction associated with RSCVs, with an emphasis on P. aeruginosa. Meanwhile, some non-pathogenic bacteria such as Pseudomonas fluorescence, Pseudomonas putida and Bacillus subtilis will be also included. Remarkable emphasis is given on intrinsic functions of such hyper-biofilm formation characteristic as well as its potential applications in several biocatalytic transformations including wastewater treatment, microbial fermentation, and plastic degradation. Hopefully, this review will attract the interest of researchers in various fields and shape future research focused not only on evolutionary biology but also on biotechnological applications related to RSCVs.

PMID:34718136 | DOI:10.1016/j.biotechadv.2021.107862

J Transl Med. 2021 Oct 30;19(1):452. doi: 10.1186/s12967-021-03099-4.

ABSTRACT

The discovery of the Cystic fibrosis (CF) gene in 1989 has paved the way for incredible progress in treating the disease such that the mean survival age of individuals living with CF is now ~58 years in Canada. Recent developments in gene targeting tools and new cell and animal models have re-ignited the search for a permanent genetic cure for all CF. In this review, we highlight some of the more recent gene therapy approaches as well as new models that will provide insight into personalized therapies for CF.

PMID:34717671 | DOI:10.1186/s12967-021-03099-4

BMC Med Genomics. 2021 Oct 30;14(1):258. doi: 10.1186/s12920-021-01106-7.

ABSTRACT

BACKGROUND: We previously reported that expression of a miR-138 mimic or knockdown of SIN3A in primary cultures of cystic fibrosis (CF) airway epithelia increased ΔF508-CFTR mRNA and protein levels, and partially restored CFTR-dependent chloride transport. Global mRNA transcript profiling in ΔF508-CFBE cells treated with miR-138 mimic or SIN3A siRNA identified two genes, SYVN1 and NEDD8, whose inhibition significantly increased ΔF508-CFTR trafficking, maturation, and function. Little is known regarding the dynamic changes in the CFTR gene network during such rescue events. We hypothesized that analysis of condition-specific gene networks from transcriptomic data characterizing ΔF508-CFTR rescue could help identify dynamic gene modules associated with CFTR biogenesis.

METHODS: We applied a computational method, termed M-module, to analyze multiple gene networks, each of which exhibited differential activity compared to a baseline condition. In doing so, we identified both unique and shared gene pathways across multiple differential networks. To construct differential networks, gene expression data from CFBE cells were divided into three groups: (1) siRNA inhibition of NEDD8 and SYVN1; (2) miR-138 mimic and SIN3A siRNA; and (3) temperature (27 °C for 24 h, 40 °C for 24 h, and 27 °C for 24 h followed by 40 °C for 24 h).

RESULTS: Interrogation of individual networks (e.g., NEDD8/SYVN1 network), combinations of two networks (e.g., NEDD8/SYVN1 + temperature networks), and all three networks yielded sets of 1-modules, 2-modules, and 3-modules, respectively. Gene ontology analysis revealed significant enrichment of dynamic modules in pathways including translation, protein metabolic/catabolic processes, protein complex assembly, and endocytosis. Candidate CFTR effectors identified in the analysis included CHURC1, GZF1, and RPL15, and siRNA-mediated knockdown of these genes partially restored CFTR-dependent transepithelial chloride current to ΔF508-CFBE cells.

CONCLUSIONS: The ability of the M-module to identify dynamic modules involved in ΔF508 rescue provides a novel approach for studying CFTR biogenesis and identifying candidate suppressors of ΔF508.

PMID:34717611 | DOI:10.1186/s12920-021-01106-7

Physiol Res. 2021 Oct 30;70(6). Online ahead of print.

ABSTRACT

There are concerns about altered vascular functions that could play an important role in the pathogenesis and influence the severity of chronic disease, however, increased cardiovascular risk in paediatric cystic fibrosis (CF) has not been yet fully understood. Aim was to analyse vascular disease risk and investigate changes over times in CF and controls. We prospectively enrolled 22 CF subjects (a median age of 16.07 years), and 22 healthy demographically matched controls (a median age of 17.28 years) and determined endothelial function. We utilised a combined diagnostic approach by measuring the plethysmographic Reactive Hyperemia Index (RHI) as the post-to preocclusive endothelium-dependent changes of vascular tone, and biomarkers that are known to be related to endothelial dysfunction (ED): asymmetric dimethyl arginine (ADMA), high-sensitive CRP (hsCRP), VCAM-1 and E-selectin. RHI values were significantly lower in CF young adults (p<0.005). HsCRP (p<0.005), E-selectin (p<0.001) and VCAM-1 (p<0.001) were significantly increased in CF patients since childhood. The findings have provided a detailed account of the ongoing process of microvascular dysfunction with gradual progression with the age of CF patients, making them further at risk of advanced vascular disease. Elevations of biomarkers in CF children with not yet demonstrated RHI changes but with significantly reduced RHI in adulthood and lipid profile changes indicate the possible occurrence of ED with CF-related specific risk factors over time and will enable us to provide the best possible support.

PMID:34717066

Aliment Pharmacol Ther. 2021 Oct 30. doi: 10.1111/apt.16673. Online ahead of print.

ABSTRACT

BACKGROUND: New developments in MRI have allowed the non-invasive, accurate measurement of the small bowel water content (SBWC).

AIMS: To collate studies measuring SBWC following ingestion of a range of foods in both health and disease to provide data for adequately powering future studies in this area.

METHODS: This collation brings together 29 studies including 954 participants (530 healthy, 54 diverticulosis, 255 IBS, 53 functional constipation, 12 cystic fibrosis, 15 Crohn's disease, 20 coeliac disease, 15 scleroderma) which have been carried out in a single centre using comparable study designs.

RESULTS: Fasting SBWC (mean 82 [SD 65] mL) shows high variability with a small decline with advancing age (healthy volunteers only; individual patient data). Fasting values are increased in untreated coeliac disease (202 [290] mL, P = 0.004). Post-prandial SBWC shows less intra-individual variability than fasting values in healthy volunteers. SBWC is increased by eating, most markedly by high fat meals but also by fibre, both viscous and particulate. Indigestible residue accumulates in late post-prandial period but empties soon after ingestion of a high calorie meal which produces a significant drop (by 50 [52] mL) in healthy volunteers. The associated fall in SBWC is abnormal in people with cystic fibrosis (SBWC reduced by 10 [121] mL, P = 0.002) and in people with irritable bowel syndrome with diarrhoea (SBWC reduced by 17 [43] mL, P = 0.007).

CONCLUSIONS: SBWC as assessed by MRI is a valuable biomarker indicating the balance of secretion and absorption in health and disease and the impact of treatments.

PMID:34716925 | DOI:10.1111/apt.16673

Cell Mol Life Sci. 2021 Oct 29. doi: 10.1007/s00018-021-03994-5. Online ahead of print.

ABSTRACT

Protein misfolding is involved in a large number of diseases, among which cystic fibrosis. Complex intra- and inter-domain folding defects associated with mutations in the cystic fibrosis transmembrane regulator (CFTR) gene, among which p.Phe508del (F508del), have recently become a therapeutical target. Clinically approved correctors such as VX-809, VX-661, and VX-445, rescue mutant protein. However, their binding sites and mechanisms of action are still incompletely understood. Blind docking onto the 3D structures of both the first membrane-spanning domain (MSD1) and the first nucleotide-binding domain (NBD1), followed by molecular dynamics simulations, revealed the presence of two potential VX-809 corrector binding sites which, when mutated, abrogated rescue. Network of amino acids in the lasso helix 2 and the intracellular loops ICL1 and ICL4 allosterically coupled MSD1 and NBD1. Corrector VX-445 also occupied two potential binding sites on MSD1 and NBD1, the latter being shared with VX-809. Binding of both correctors on MSD1 enhanced the allostery between MSD1 and NBD1, hence the increased efficacy of the corrector combination. These correctors improve both intra-domain folding by stabilizing fragile protein-lipid interfaces and inter-domain assembly via distant allosteric couplings. These results provide novel mechanistic insights into the rescue of misfolded proteins by small molecules.

PMID:34714360 | DOI:10.1007/s00018-021-03994-5

BMJ Case Rep. 2021 Oct 28;14(10):e243979. doi: 10.1136/bcr-2021-243979.

ABSTRACT

Mycobacterium abscessus is an emerging multidrug-resistant non-tuberculous mycobacterium (NTM) with high prevalence in patients with cystic fibrosis. However, studies on antimicrobial susceptibilities and effective treatments against M. abscessus are still limited. Nitric oxide (NO) is important in innate immune response to various infections, including mycobacterial infections. In this case study, we describe a compassionate treatment of inhaled NO (iNO) at 150-250 ppm for 4 weeks. The dosing strategy proposed for this treatment was selected to minimise the potential of adverse events, while maximising the antibacterial effectiveness of NO, and was found to be safe, well tolerated and resulted in positive clinical findings including improvement in patient well-being, CT scan values, quality of life and bacterial load. Taken together, these observations may indicate that iNO could play a crucial role and potentially serve as a reliable option in the treatment of patients with chronic refractory NTM lung infection.

PMID:34711619 | DOI:10.1136/bcr-2021-243979

Curr Opin Microbiol. 2021 Oct 25;64:125-132. doi: 10.1016/j.mib.2021.09.010. Online ahead of print.

ABSTRACT

Pseudomonas aeruginosa, a bacterium characterized for its low antibiotics' susceptibility, is one of the most relevant opportunistic pathogens, causing infections at hospitals and in cystic fibrosis patients. Besides its relevance for human health, P. aeruginosa colonizes environmental ecosystems; therefore the elements driving its infectivity and antibiotic resistance must be analyzed from a One-Health perspective. Although some epidemic clones have been described, there are not specific lineages linked to infections, suggesting that P. aeruginosa virulence and antibiotic resistance determinants evolved in nature to play functions other than infecting the human host and avoiding antimicrobial treatment. Herein, we review current information on the population structure of P. aeruginosa and on the functional role that its resistance and virulence determinants have in non-clinical ecosystems.

PMID:34710741 | DOI:10.1016/j.mib.2021.09.010

Int Forum Allergy Rhinol. 2021 Oct 28. doi: 10.1002/alr.22891. Online ahead of print.

NO ABSTRACT

PMID:34709729 | DOI:10.1002/alr.22891

Acta Physiol (Oxf). 2021 Oct 28:e13737. doi: 10.1111/apha.13737. Online ahead of print.

ABSTRACT

Cystic fibrosis (CF) is caused by mutation in the chloride channel CFTR and cause dysfunctional trans-epithelial fluid transport in e.g., airways, intestine and pancreatic ducts. The most common co-morbidity of people with CF is cystic fibrosis-related diabetes (CFRD), with a prevalence of ~50 % in adults1 . Why people with CF develop CFRD is still an open question. In this issue of Acta Physiologica, Li at colleagues2 describe the chloride transporter Slc26a9 to be important in regulation of pancreatic exocrine fluid secretion and pancreatic endocrine function (Fig. 1). Thereby they add one more piece to our understanding of chloride fluxes in the pancreas.

PMID:34709722 | DOI:10.1111/apha.13737

Front Cell Dev Biol. 2021 Oct 11;9:742891. doi: 10.3389/fcell.2021.742891. eCollection 2021.

ABSTRACT

The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein is a cAMP-activated anion channel that is critical for regulating fluid and ion transport across the epithelium. This process is disrupted in CF epithelia, and patients harbouring CF-causing mutations experience reduced lung function as a result, associated with the increased rate of mortality. Much progress has been made in CF research leading to treatments that improve CFTR function, including small molecule modulators. However, clinical outcomes are not necessarily mutation-specific as individuals harboring the same genetic mutation may present with varying disease manifestations and responses to therapy. This suggests that the CFTR protein may have alternative functions that remain under-appreciated and yet can impact disease. In this mini review, we highlight some notable research implicating an important role of CFTR protein during early lung development and how mutant CFTR proteins may impact CF airway disease pathogenesis. We also discuss recent novel cell and animal models that can now be used to identify a developmental cause of CF lung disease.

PMID:34708042 | PMC:PMC8542926 | DOI:10.3389/fcell.2021.742891

Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2021 Sept 28;46(9):949-957. doi: 10.11817/j.issn.1672-7347.2021.210210.

ABSTRACT

OBJECTIVES: Many studies have shown that respiratory syncytial virus persistent infection may be the main cause of chronic respiratory pathology.However, the mechanism is unclear. Cystic fibrosis transmembrane conduction regulator (CFTR) is an apical membrane chloride channel, which is very important for the regulation of epithelial fluid, chloride ion, and bicarbonate transport. CFTR dysfunction will lead to changes in bronchial secretions and impair mucus clearance, which is related to airway inflammation. In our previous study, we observed the down-regulation of CFTR in airway epithelial cells in respiratory syncytial virus (RSV) infected mouse model. In this study, we further investigated the expression and function of CFTR by constructing an airway epithelial cell model of RSV persistent infection.

METHODS: 16HBE14o- cells were infected with RSV at 0.01 multiplicity of infection (MOI). The expression of CFTR was detected by real-time RT-PCR, immunofluorescence, and Western blotting. The intracellular chloride concentration was measured by N-(ethoxycarbonylmethyl)-6-methoxyquinolium bromide (MQAE) and the chloride current was measured by whole-cell patch clamp recording.

RESULTS: 16HBE14o- cells infected with RSV were survived to successive passages of the third generation (G3), while the expression and function of CFTR was progressively decreased upon RSV infection from the first generation (G1) to G3. Exposure of 16HBE14o- cells to RSV led to the gradual increase of TGF-β1 as well as phosphorylation of Smad2 following progressive RSV infection. Disruption of TGF-β1 signaling by SB431542 prevented Smad2 phosphorylation and rescued the expression of CFTR.

CONCLUSIONS: RSV infection can lead to defective CFTR function in airway epithelial cells, which may be mediated via activation of TGF-β1 signaling pathway.

PMID:34707004 | DOI:10.11817/j.issn.1672-7347.2021.210210

Thorax. 2021 Oct 27:thoraxjnl-2021-217782. doi: 10.1136/thoraxjnl-2021-217782. Online ahead of print.

ABSTRACT

RATIONALE: Inhaled tobramycin and oral azithromycin are common chronic therapies in people with cystic fibrosis and Pseudomonas aeruginosa airway infection. Some studies have shown that azithromycin can reduce the ability of tobramycin to kill P. aeruginosa. This trial was done to test the effects of combining azithromycin with inhaled tobramycin on clinical and microbiological outcomes in people already using inhaled tobramycin. We theorised that those randomised to placebo (no azithromycin) would have greater improvement in forced expiratory volume in one second (FEV1) and greater reduction in P. aeruginosa sputum in response to tobramycin.

METHODS: A 6-week prospective, randomised, placebo-controlled, double-blind trial testing oral azithromycin versus placebo combined with clinically prescribed inhaled tobramycin in individuals with cystic fibrosis and P. aeruginosa airway infection.

RESULTS: Over a 6-week period, including 4 weeks of inhaled tobramycin, the relative change in FEV1 did not statistically significantly differ between groups (azithromycin (n=56) minus placebo (n=52) difference: 3.44%; 95% CI: -0.48 to 7.35; p=0.085). Differences in secondary clinical outcomes, including patient-reported symptom scores, weight and need for additional antibiotics, did not significantly differ. Among the 29 azithromycin and 35 placebo participants providing paired sputum samples, the 6-week change in P. aeruginosa density differed in favour of the placebo group (difference: 0.75 log10 CFU/mL; 95% CI: 0.03 to 1.47; p=0.043).

CONCLUSIONS: Despite having greater reduction in P. aeruginosa density in participants able to provide sputum samples, participants randomised to placebo with inhaled tobramycin did not experience significantly greater improvements in lung function or other clinical outcomes compared with those randomised to azithromycin with tobramycin.

PMID:34706982 | DOI:10.1136/thoraxjnl-2021-217782

Int Forum Allergy Rhinol. 2021 Oct 26. doi: 10.1002/alr.22907. Online ahead of print.

ABSTRACT

BACKGROUND: Abnormal chloride (Cl- ) transport dehydrates airway surface liquid (ASL) in sinonasal epithelium leading to mucus stasis and chronic rhinosinusitis. As an experimental epithelium, rabbit tissue provides an excellent representation of human sinus disease, and the rabbit sinusitis model is both established and well suited for therapeutic interventions in vivo. Our objective in this study was to evaluate whether ivacaftor reverses the consequences of Pseudomonas aeruginosa-induced acquired cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction.

METHODS: Rabbit nasal cavities were assessed for responsiveness to ivacaftor in vivo (by nasal potential difference [NPD] assay). Rabbit nasal epithelial (RNE) cultures were incubated with an ultrafiltrate of P aeruginosa (PAO1 strain) for 4 hours and tested for acquired CFTR dysfunction. Markers of mucociliary function, including airway surface liquid depth (ASL), periciliary liquid depth (PCL), ciliary beat frequency (CBF), and mucociliary transport (MCT), were measured by micro-optical coherence tomography (μOCT) after PAO1 and/or ivacaftor incubation.

RESULTS: Ivacaftor resulted in a significant mean NPD polarization of 21.8 ± 2.1 mV, which was significantly greater than that seen in the low Cl- control (12.9 ± 1.3; p = 0.01). PAO1 exposure induced a state of acquired CFTR dysfunction in rabbit nasal epithelium as measured by forskolin-stimulated short-circuit current (ISC ) (control, 37.0 ± 1.1 μA/cm2 ; PAO1, 24.4 ± 1.1 μA/cm2 ; p < 0.001). RNE cultures exposed to PAO1 had inhibited mucociliary function, whereas coincubation with ivacaftor restored mucociliary clearance, as measured by μOCT.

CONCLUSION: In rabbit nasal epithelium, ivacaftor robustly stimulates CFTR-mediated Cl- secretion and normalizes ASL and CBF in PAO1-induced acquired CFTR dysfunction. Preclinical testing of CFTR potentiators as therapy for P aeruginosa rabbit sinusitis is planned.

PMID:34704673 | DOI:10.1002/alr.22907

Pediatr Pulmonol. 2021 Oct 27. doi: 10.1002/ppul.25745. Online ahead of print.

ABSTRACT

Caring for people with Cystic Fibrosis (CF) has changed considerably since the first description of the disorder and continues to evolve in the era of highly effective modulator therapy. These new treatment advancements are resulting in improved health outcomes in an ever-growing adult population with improved long-term survival. This article explores potential co-morbidities and mental health implications associated with increased longevity and survivorship. It also considers the need for further evolution in patient centered care with an expanded health care team in a more virtually connected world. This article is protected by copyright. All rights reserved.

PMID:34704669 | DOI:10.1002/ppul.25745

Acta Paediatr. 2021 Oct 26. doi: 10.1111/apa.16167. Online ahead of print.

ABSTRACT

AIM: There are two types of intestinal volvulus: midgut (MGV) and segmental (SV). Patients with different types of intestinal volvulus are often included in the same case series, which may affect the perception of how severe "intestinal volvuli" are. We aimed to compare both types of intestinal volvulus.

METHODS: Retrospective observational study including all patients with MGV and SV up to 28 days of life admitted to a tertiary hospital in Spain over a 20-year-period (1999-2019). A comparison between groups and a logistic regression model for mortality were done.

RESULTS: We identified 32 patients: 23 MGV and 9 SV. Malrotation was exclusive of MGV. Prenatal diagnosis, cystic fibrosis, and intestinal resection were significantly more frequent in SV. Surgery was performed at a significantly lower age in SV. The mortality observed in acute MGV with intestinal compromise (41.7%) is four times higher than the mortality of SV (11.1%). The overall mortality of all MGV patients (21.7%) is almost twice that of SV. Mortality was best predicted by the presence of hemodynamic instability (OR 27.5 95% CI 2.50-302.17; p = 0.007).

CONCLUSION: SV and MGV have a different clinical presentation. Hemodynamic instability is the major risk factor for death.

PMID:34704280 | DOI:10.1111/apa.16167

Nat Commun. 2021 Oct 26;12(1):6193. doi: 10.1038/s41467-021-26517-z.

ABSTRACT

Staphylococcus aureus bi-component pore-forming leukocidins are secreted toxins that directly target and lyse immune cells. Intriguingly, one of the leukocidins, Leukocidin AB (LukAB), is found associated with the bacterial cell envelope in addition to secreted into the extracellular milieu. Here, we report that retention of LukAB on the bacterial cells provides S. aureus with a pre-synthesized active toxin that kills immune cells. On the bacteria, LukAB is distributed as discrete foci in two distinct compartments: membrane-proximal and surface-exposed. Through genetic screens, we show that a membrane lipid, lysyl-phosphatidylglycerol (LPG), and lipoteichoic acid (LTA) contribute to LukAB deposition and release. Furthermore, by studying non-covalently surface-bound proteins we discovered that the sorting of additional exoproteins, such as IsaB, Hel, ScaH, and Geh, are also controlled by LPG and LTA. Collectively, our study reveals a multistep secretion system that controls exoprotein storage and protein translocation across the S. aureus cell wall.

PMID:34702812 | DOI:10.1038/s41467-021-26517-z

Pulmonology. 2021 Oct 23:S2531-0437(21)00194-X. doi: 10.1016/j.pulmoe.2021.09.004. Online ahead of print.

NO ABSTRACT

PMID:34702678 | DOI:10.1016/j.pulmoe.2021.09.004

J Pediatr. 2021 Nov;238:214. doi: 10.1016/j.jpeds.2021.08.043.

NO ABSTRACT

PMID:34702496 | DOI:10.1016/j.jpeds.2021.08.043

Am J Clin Pathol. 2021 Oct 26:aqab177. doi: 10.1093/ajcp/aqab177. Online ahead of print.

ABSTRACT

OBJECTIVES: The cytomorphologic findings of bronchoalveolar lavage (BAL) in pediatrics were correlated with clinical symptoms.

METHODS: Patient demographics, clinical symptoms/history, cytomorphologic findings, and oil red O (ORO) staining of 100 pediatric patients who underwent BAL between 2014 and 2016 were reviewed at a large academic institution.

RESULTS: Of the 100 patients (males/females, 62:38), the most common conditions for BAL included cough (46/100), reflux (39/100), pneumonia (30/100), dysphagia (22/100), asthma (19/100), and cystic fibrosis (15/100). Sixteen of 100 patients were admitted with pulmonary symptoms from the emergency department. Cytomorphologic findings showed acute inflammation in 37 BALs and chronic inflammation in 9. Abundant thick mucin was present in 3 cytology cases from patients with cystic fibrosis. Fungal elements were detected in 3 cases (Candida, Aspergillus, and Pneumocystis jirovecii) and viral effects (rhinovirus) in one. Thirty-seven of 100 had rare ORO-positive lipid-laden macrophages (LLMs), 7 of 100 had moderate LLMs, 11 of 100 had numerous LLMs, 18 of 100 had positive staining without the degree of staining, 25 of 100 had negative ORO staining, and 2 of 100 had noncontributory ORO staining. An iron stain was done on 15 BALs (2 positive, 9 negative, and 4 noncontributory).

CONCLUSIONS: BAL cytology is a useful tool in pediatrics to discriminate underlying causes of aerodigestive system conditions, while ORO staining may occasionally help.

PMID:34698346 | DOI:10.1093/ajcp/aqab177