A low molecular weight alginate oligosaccharide disrupts pseudomonal microcolony formation and enhances antibiotic effectiveness.

Antimicrob Agents Chemother. 2017 Jun 19;:

Authors: Pritchard MF, Powell LC, Jack AA, Powell K, Beck K, Florance H, Forton J, Rye PD, Dessen A, Hill KE, Thomas DW

Abstract
In chronic respiratory disease the formation of dense, 3-dimensional 'micro colonies' by Pseudomonas aeruginosa within the airway plays an important role in contributing to resistance to treatment. An in vitro biofilm model of pseudomonal microcolony formation using artificial sputum (AS) medium was established to study the effects of low molecular weight alginate oligomers (OligoG CF-5/20) on pseudomonal growth, microcolony formation and the efficacy of colistin. The studies employed clinical cystic fibrosis (CF) isolates (n=3) and reference non-mucoid and mucoid multi-drug resistant (MDR) CF isolates (n=7). Bacterial growth, biofilm development and disruption were studied using cell-viability assays and image analysis using scanning electron- and confocal laser scanning microscopy. Pseudomonal growth in AS medium was associated with increased ATP production (p<0.05) and the formation (at 48 h) of discrete (>10 μm) microcolonies. In conventional growth medium, colistin retained an ability to inhibit growth of planktonic bacteria, although the MIC was increased (0.1 to 0.4 μg/ml) in AS medium versus. In contrast, in an established biofilm model in the AS medium, the efficacy of colistin was decreased. OligoG CF-5/20 (≥2%) treatment however, induced dose-dependent biofilm disruption (p<0.05), and led to colistin retaining its antimicrobial activity (p<0.05). Whilst circular dichroism indicated that OligoG CF-5/20 did not change the orientation of the alginate carboxyl groups, mass-spectrometry demonstrated that the oligomers induced dose-dependent (>0.2%; p<0.05) reductions in pseudomonal quorum sensing signaling. These findings reinforce the potential clinical significance of microcolony formation in the CF lung, and highlight a novel approach to treat MDR pseudomonal infections.

PMID: 28630204 [PubMed - as supplied by publisher]

Pseudomonas Quinolone Signal (PQS) Induces Oxidative Stress and inhibits Heme Oxygenase-1 Expression in Lung Epithelial Cells.

Infect Immun. 2017 Jun 19;:

Authors: Abdalla MY, Hoke T, Seravalli J, Switzer BL, Bavitz M, Fliege JD, Murphy PJ, Britigan BE

Abstract
Pseudomonas aeruginosa (PA) causes lung infection in patients with cystic fibrosis (CF). Pseudomonas Quinolone Signal (PQS) is a secreted PA virulence factor that contributes to the pathogenicity of PA. We were able to detect PQS in sputum samples from CF patients infected with PA, but not in samples from uninfected patients. We then tested the hypothesis that PQS induces oxidative stress in host cells by determining the ability of PQS to induce production of reactive oxygen species (ROS) in lung epithelial cells (A549 and primary normal human bronchial epithelial (NHBE)) and macrophages (J774A.1 and THP-1). ROS production induced by PQS was detected using fluorescent probes (dichloro-dihydro-fluorescein diacetate (DCF-DA), dihydroethidium (DHE), and MitoSOX Red) in conjunction with confocal microscopy and flow cytometry. PQS induced ROS production in lung epithelial cells (A549 and NHBE) and macrophages (J774A.1 and THP-1). NHBE cells were sensitive to as low as 500 ng/ml PQS. PQS significantly induced early apoptosis (p< 0.05, n =6) in lung epithelial cells, as measured by annexin/PI detection using flow cytometry. However, no change in apoptosis upon PQS treatment was seen with J774A.1 cells. Heme-oxygenase-1 protein (HO-1) is an anti-oxidant enzyme usually induced by oxidative stress. Interestingly, incubation with PQS significantly reduced HO-1 and NrF2 expression in A549 cells and NHBE cells, but increased HO-1 expression in J774A.1 cells (p<0.05, n=3), as determined by immunoblot and densitometry. These PQS effects on host cells could play an important role in the pathogenicity of PA infections.

PMID: 28630072 [PubMed - as supplied by publisher]

Chemistry and Biology of the Pyrrole-Imidazole Alkaloids.

Alkaloids Chem Biol. 2017;77:117-219

Authors: Lindel T

Abstract
More than a decade after our last review on the chemistry of the pyrrole-imidazole alkaloids, it was time to analyze once more the developments in that field. The comprehensive article focusses on the total syntheses of pyrrole-imidazole alkaloids that have appeared since 2005. The classic monomeric pyrrole-imidazole alkaloids have all been synthesized, sometimes primarily to demonstrate the usefulness of a new method, as in the case of the related molecules agelastatin A and cyclooroidin with more than 15 syntheses altogether. The phakellin skeleton has been made more than 10 times, too, with a focus on the target structure itself. Thus, some of the pyrrole-imidazole alkaloids are now available in gram amounts, and the supply problem has been solved. The total synthesis of the dimeric pyrrole-imidazole alkaloids is still mostly in its pioneering phase with two routes to palau'amine and massadine discovered and three routes to the axinellamines and ageliferin. In addition, the review summarizes recent discoveries regarding the biological activity of the pyrrole-imidazole alkaloids. Regarding the biosynthesis of sceptrin, a pathway is proposed that starts from nagelamide I and proceeds via two electrocyclizations and reduction.

PMID: 28212701 [PubMed - indexed for MEDLINE]

Prospective Endoscopic Ultrasound-Based Approach to the Evaluation of Idiopathic Pancreatitis: Causes, Response to Therapy, and Long-term Outcome.

Am J Gastroenterol. 2016 Sep;111(9):1339-48

Authors: Wilcox CM, Seay T, Kim H, Varadarajulu S

Abstract
OBJECTIVES: Although idiopathic pancreatitis is common, the natural history is not well studied, and the best diagnostic approach to both single and multiple attacks remains undefined.
METHODS: We prospectively evaluated patients with idiopathic pancreatitis over a 10-year period, and clinical information for each episode was reviewed. Endoscopic ultrasound (EUS) was performed in all patients. Patients with microlithiasis or bile duct stones were referred for cholecystectomy and endoscopic retrograde cholangiopancreatography (ERCP), respectively. For those with a single attack, if EUS was normal or chronic pancreatitis or pancreas divisum was diagnosed, the patient was followed up for recurrence. For those with multiple attacks and a negative EUS, ERCP and sphincter of Oddi manometry with endoscopic therapy as appropriate were recommended. All patients were followed up in the long term to evaluate for recurrent pancreatitis, the primary study end point.
RESULTS: Over the study period, 201 patients were identified (80 single attack, 121 multiple attacks; mean age 53 years, range 17-95 years, s.d. 16.3 years; and 53% female). After EUS, 54% of patients with a single attack were categorized as idiopathic, and for multiple attacks sphincter of Oddi dysfunction (SOD) was the most common diagnosis (41%). Long-term follow-up (median 37 months; interquartile range 19-70 months) documented recurrence of pancreatitis in 15 (24%; 95% confidence interval (CI), 15-38%) patients with a single attack and in 48 (49%; 95% CI, 38-62%) patients with multiple attacks. Despite endoscopic therapy, patients with pancreas divisum and SOD had relapse rates of 50% (95% CI, 35 to 68%) and 55% (95% CI, 31 to 82%), respectively.
CONCLUSIONS: Following a single idiopathic attack of pancreatitis and a negative EUS examination, relapse was infrequent. Despite endoscopic therapy, patients with multiple attacks, especially those attributed to pancreas divisum and SOD, had high rates of recurrence. EUS may be a useful, minimally invasive tool for the diagnostic evaluation of idiopathic pancreatitis. The study was listed in Clinicaltrials.gov NCT00609726.

PMID: 27325219 [PubMed - indexed for MEDLINE]

Gene correction in patient-specific iPSCs for therapy development and disease modeling.

Hum Genet. 2016 Sep;135(9):1041-58

Authors: Jang YY, Ye Z

Abstract
The discovery that mature cells can be reprogrammed to become pluripotent and the development of engineered endonucleases for enhancing genome editing are two of the most exciting and impactful technology advances in modern medicine and science. Human pluripotent stem cells have the potential to establish new model systems for studying human developmental biology and disease mechanisms. Gene correction in patient-specific iPSCs can also provide a novel source for autologous cell therapy. Although historically challenging, precise genome editing in human iPSCs is becoming more feasible with the development of new genome-editing tools, including ZFNs, TALENs, and CRISPR. iPSCs derived from patients of a variety of diseases have been edited to correct disease-associated mutations and to generate isogenic cell lines. After directed differentiation, many of the corrected iPSCs showed restored functionality and demonstrated their potential in cell replacement therapy. Genome-wide analyses of gene-corrected iPSCs have collectively demonstrated a high fidelity of the engineered endonucleases. Remaining challenges in clinical translation of these technologies include maintaining genome integrity of the iPSC clones and the differentiated cells. Given the rapid advances in genome-editing technologies, gene correction is no longer the bottleneck in developing iPSC-based gene and cell therapies; generating functional and transplantable cell types from iPSCs remains the biggest challenge needing to be addressed by the research field.

PMID: 27256364 [PubMed - indexed for MEDLINE]

Combination antimicrobial susceptibility testing for acute exacerbations in chronic infection of Pseudomonas aeruginosa in cystic fibrosis.

Cochrane Database Syst Rev. 2017 Jun 19;6:CD006961

Authors: Waters V, Ratjen F

Abstract
BACKGROUND: Antibiotic therapy for acute pulmonary exacerbations in people with cystic fibrosis is usually chosen based on the results of antimicrobial susceptibility testing of individual drugs. Combination antimicrobial susceptibility testing assesses the efficacy of drug combinations including two or three antibiotics in vitro and can often demonstrate antimicrobial efficacy against bacterial isolates even when individual antibiotics have little or no effect. Therefore, choosing antibiotics based on combination antimicrobial susceptibility testing could potentially improve response to treatment in people with cystic fibrosis with acute exacerbations. This is an updated version of a previously published review.
OBJECTIVES: To compare antibiotic therapy based on conventional antimicrobial susceptibility testing to antibiotic therapy based on combination antimicrobial susceptibility testing in the treatment of acute pulmonary exacerbations in people with cystic fibrosis and chronic infection with Pseudomonas aeruginosa.
SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Cystic Fibrosis Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Date of latest search: 19 December 2016.We also searched ongoing trials registries. Date of latest search: 08 March 2017.
SELECTION CRITERIA: Randomised and quasi-randomised controlled studies of antibiotic therapy based on conventional antimicrobial susceptibility testing compared to antibiotic therapy based on combination antimicrobial susceptibility testing in the treatment of acute pulmonary exacerbations in cystic fibrosis due to chronic infection with Pseudomonas aeruginosa.
DATA COLLECTION AND ANALYSIS: Both authors independently selected studies, assessed their quality and extracted data from eligible studies. Additionally, the authors contacted the study investigators to obtain further information.
MAIN RESULTS: The search identified one multicentre study eligible for inclusion in the review. This study prospectively assessed whether the use of multiple combination bactericidal antibiotic testing improved clinical outcomes in participants with acute pulmonary exacerbations of cystic fibrosis who were infected with multiresistant bacteria. A total of 132 participants were randomised in the study. The study investigators provided data specific to the 82 participants who were only infected with Pseudomonas aeruginosa for their primary outcome of time until next pulmonary exacerbation. For participants specifically infected with only Pseudomonas aeruginosa, the hazard ratio of a subsequent exacerbation was 0.82, favouring the control group (95% confidence interval 0.44 to 1.51) (P = 0.52). No further data for any of this review's outcomes specific to participants infected with Pseudomonas aeruginosa were available. The risk of bias for the included study was deemed to be low. The quality of the evidence was moderate for the only outcome providing data solely for individuals with infection due to Pseudomonas aeruginosa. For other outcomes, we were unable to judge the quality of the evidence as no data were available for the relevant subset of participants.
AUTHORS' CONCLUSIONS: The current evidence, limited to one study, shows that there is insufficient evidence to determine effect of choosing antibiotics based on combination antimicrobial susceptibility testing compared to choosing antibiotics based on conventional antimicrobial susceptibility testing in the treatment of acute pulmonary exacerbations in people with cystic fibrosis with chronic Pseudomonas aeruginosa infection. A large international and multicentre study is needed to further investigate this issue.The only study included in the review was published in 2005, and we have not identified any further relevant studies up to March 2017. We therefore do not plan to update this review until new studies are published.

PMID: 28628280 [PubMed - as supplied by publisher]

[Excess weight in patients with cystic fibrosis: is it always beneficial?]

Nutr Hosp. 2017 Jun 05;34(3):578-583

Authors: González Jiménez D, Muñoz-Codoceo R, Garriga-García M, Molina-Arias M, Álvarez-Beltrán M, García-Romero R, Martínez-Costa C, Meavilla-Olivas SM, Peña-Quintana LR, Gallego Gutiérrez S, Marugán de Miguelsanz JM, Suárez Cortina L, Castejón Ponce EN, Leis Trabazo R, Martín Cruz F, Díaz Martín JJ, Bousoño García C

Abstract
INTRODUCTION: The primary objective of this study was to find out the prevalence of overweight and obese status, as well as their association to pulmonary function, total cholesterol and vitamin D in patients with cystic fibrosis (CF).
MATERIALS AND METHODS: This is a multicenter descriptive and cross-sectional study. Twelve Spanish hospitals participated. 451 patients with CF were included. Adults were classified according to body mass index (BMI) and children were classified according to BMI percentiles (WHO tables). Pearson's correlation, Anova, Student's t-test and multiple linear regression were conducted.
RESULTS: Mean age was 12.3 (range 4-57) years old, 51% were male and 18% had pancreatic sufficiency. Participants were classified in five nutritional status categories: 12% were malnourished; 57%, at nutritional risk; 24%, normally nourished; 6%, overweight; and 1%, obese. Pulmonary function in overweight or obese patients (91 ± 19%) was better than in malnourished patients (77 ± 24%) (p = 0.017). However, no difference was observed between those at nutritional risk (86 ± 19%) or normally nourished (90 ± 22%) groups. Overweight and obese patients had higher levels of total cholesterol (p = 0.0049), a greater proportion of hypercholesterolemia (p = 0.001), as well as lower levels of 25 OH vitamin D (p = 0.058).
CONCLUSIONS: Prevalence of overweight and obese was 6 and 1%. Excess weight status does not offer any benefit in pulmonary function in comparison to normally nourished patients.

PMID: 28627192 [PubMed - in process]

Continuous glucose monitoring in a cystic fibrosis patient to predict pulmonary exacerbation?

J Cyst Fibros. 2017 Jun 15;:

Authors: Inman TB, Proudfoot JA, Lim M, Demeterco-Berggren C

Abstract
Patients with cystic fibrosis (CF) experience a significant decline in pulmonary status before the diagnosis of cystic fibrosis related diabetes (CFRD). We hypothesized that hyperglycemia may be a factor in the decline of pulmonary function and increased frequency of pulmonary exacerbations. Long term continuous glucose monitoring (CGM) has not been reported in patients with CF and impaired glucose tolerance. We performed CGM for three months in a 17year old male with F508del and F553X CF mutations, baseline forced expiratory volume in 1s (FEV1) of 92% predicted, and impaired glucose tolerance to evaluate changes in glucose levels prior to the diagnosis of a pulmonary exacerbation. Results revealed elevated overnight, fasting and post-prandial glucose levels up to one week prior to diagnosis of a pulmonary exacerbation compared to baseline. In addition, mean glucose was elevated and the patient spent a greater percentage of time with interstitial glucose>140mg/dL up to one week prior to diagnosis of a pulmonary exacerbation. This emphasizes the hypothesis that hyperglycaemia may be a factor in pulmonary exacerbations in this population. This case study strengthens the evidence base to support larger longitudinal studies to understand the impact of glycaemic control and pulmonary function in patients with CF and glucose intolerance.

PMID: 28625799 [PubMed - as supplied by publisher]

Small Bowel Ultrasound beyond Inflammatory Bowel Disease: An Updated Review of the Recent Literature.

Ultrasound Med Biol. 2017 Jun 15;:

Authors: Cavalcoli F, Zilli A, Fraquelli M, Conte D, Massironi S

Abstract
The use of bowel ultrasonography (US) for the evaluation of gut diseases has increased in recent years and has been proven to provide a widely available, non-invasive and inexpensive method for the initial work-up and follow-up of different intestinal diseases, limited mostly by technical challenges posed by the patient's anatomy. The present review aims to provide an extensive overview of the main pathologic features at US examination of intestinal diseases other than inflammatory bowel disease, both acute (e.g., acute appendicitis, colonic diverticulitis, infectious diseases and ischemic conditions) and chronic (e.g., celiac disease, cystic fibrosis and other enterocolites). The identification of typical US features may help in the diagnostic process and guide the treatment approach. Therefore, the application of knowledge of the US appearance of gastrointestinal diseases is of relevance in enabling greater diagnostic performance and better patient management.

PMID: 28625560 [PubMed - as supplied by publisher]

Question 12: What do you consider when discussing treatment adherence in patients with Cystic Fibrosis?

Paediatr Respir Rev. 2017 Apr 27;:

Authors: Ohn M, Fitzgerald DA

PMID: 28625493 [PubMed - as supplied by publisher]

Oliver Smithies (1925-2017).

Nature. 2017 02 08;542(7640):166

Authors: Kucherlapati R

PMID: 28179651 [PubMed - indexed for MEDLINE]

Evaluation of a biomimetic 3D substrate based on the Human Elastin-like Polypeptides (HELPs) model system for elastolytic activity detection.

J Biotechnol. 2017 Jun 14;:

Authors: Corich L, Busetti M, Petix V, Passamonti S, Bandiera A

Abstract
Elastin is a fibrous protein that confers elasticity to tissues such as skin, arteries and lung. It is extensively cross-linked, highly hydrophobic and insoluble. Nevertheless, elastin can be hydrolysed by bacterial proteases in infectious diseases, resulting in more or less severe tissue damage. Thus, development of substrates able to reliably and specifically detect pathogen-secreted elastolytic activity is needed to improve the in vitro evaluation of the injury that bacterial proteases may provoke. In this work, two human biomimetic elastin polypeptides, HELP and HELP1, as well as the matrices derived from HELP, have been probed as substrates for elastolytic activity detection. Thirty strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients were analyzed in parallel with standard substrates, to detect proteolytic and elastolytic activity. Results point to the HELP-based 3D matrix as an interesting biomimetic model of elastin to assess bacterial elastolytic activity in vitro. Moreover, this model substrate enables to further elucidate the mechanism underlying elastin degradation at molecular level, as well as to develop biomimetic material-based devices responsive to external stimuli.

PMID: 28624377 [PubMed - as supplied by publisher]

CRISPR/Cas9-Mediated Three Nucleotide Insertion Corrects a Deletion Mutation in MRP1/ABCC1 and Restores Its Proper Folding and Function.

Mol Ther Nucleic Acids. 2017 Jun 16;7:429-438

Authors: Xu Q, Hou YX, Chang XB

Abstract
A three-nucleotide deletion in cystic fibrosis transmembrane conductance regulator/ATP-binding cassette transporter C7 (CFTR/ABCC7) resulting in the absence of phenylalanine at 508 leads to mis-fold of the mutated protein and causes cystic fibrosis. We have used a comparable three-nucleotide deletion mutant in another ABCC family member, multidrug resistance-associated protein (MRP1)/ABCC1, to determine whether CRISPR-Cas9-mediated recombination can safely and efficiently knock in three-nucleotide to correct the mutation. We have found that the rate of homology-directed recombination mediated by guideRNA (gRNA) complementary to the deletion mutant is significantly higher than the one mediated by gRNA complementary to the wild-type (WT) donor. In addition, the rate of homology-directed recombination mediated by gRNA complementary to the WT donor is significantly higher than that of gRNAs complementary to the 5' or 3' side of the deletion mutant. Interestingly, the frequency of mutations introduced by gRNA complementary to the deletion mutant is significantly higher than with gRNA complementary to WT donor. However, combination of gRNAs complementary to both WT donor and deletion mutant decreased the rate of homology-directed recombination, but did not significantly decrease the mutation rate introduced by this system. Thus, the data presented here provide guidance for designing of gRNA and donor DNA to do genome editing, especially to correct the mutations with three mismatched nucleotides, such as three-nucleotide deletion or insertion.

PMID: 28624219 [PubMed - in process]

Clinically Promising Biomarkers in Cystic Fibrosis Pulmonary Exacerbations.

Lung. 2017 Jun 16;:

Authors: Scott LK, Toner R

Abstract
Cystic fibrosis is a complex genetic disease hallmarked by repetitive infectious exacerbations that leads to destruction of airway architecture, acute on chronic inflammatory changes, and deterioration in lung function. Predicting an exacerbation may help preempt some of these changes by the initiation of swift antibiotic and anti-inflammatory therapy. A search for biomarkers that could predict exacerbations or help guide duration of antibiotic therapy is being aggressively sought. In this review, we discuss the most recent and promising biomarkers that hopefully will assist in the future management of the CF patient.

PMID: 28623538 [PubMed - as supplied by publisher]

Improved Growth Patterns in Cystic Fibrosis Mice after Loss of Histone Deacetylase 6.

Sci Rep. 2017 Jun 16;7(1):3676

Authors: Rymut SM, Corey DA, Valerio DM, Erokwu BO, Flask CA, Kelley TJ, Hodges CA

Abstract
Growth failure in cystic fibrosis (CF) patients has been well-documented and shown to correlate with poorer disease outcomes. This observation is also true in CF animal models, including mouse, pig, rat, and ferret. The etiology underlying growth deficits is unknown, and our previous work demonstrated reduced tubulin acetylation in CF cell models and tissue that is correctable by inhibition of histone deacetylase-6 (HDAC6). Here, we hypothesize that loss of HDAC6 will improve growth phenotype in a CF mouse model. Hdac6 knockout mice were crossed with F508del (CF) mice to generate F508del/Hdac6 (CF/HDA) mice. Growth, fat deposits, survival, and bioelectric measurements were analyzed. CF/HDA mice displayed improvements in length and weight with no correction of CFTR function. Mechanistically, Igf1 levels likely account for increased length and improvements in fertility. Weight gain is attributed to increased fat deposits potentially mediated by increased adipocyte differentiation. CF-related growth deficits can be improved via inhibition of HDAC6, further implicating it as a potential therapeutic target for CF.

PMID: 28623308 [PubMed - in process]

High level of β-(1,3)-d-glucan antigenaemia in cystic fibrosis in the absence of invasive fungal disease.

Diagn Microbiol Infect Dis. 2017 May 18;:

Authors: Rautemaa V, Green HD, Jones AM, Rautemaa-Richardson R

Abstract
β-(1,3)-d-glucan (BDG) is used to rule out invasive fungal disease (IFD) but its usefulness in cystic fibrosis (CF) has not been evaluated. We measured serum BDG in CF patients with no clinical suspicion of IFD. Samples from 46 adult CF patients during a stable period and during pulmonary exacerbation were tested. The association of BDG with clinical variables was analyzed. Three hundred and three non-CF patients with suspected IFD were used as comparators. Both samples were negative in 52% of CF patients, whereas 67% of comparators had only negative results (P=0.08). CF patients with pancreatic insufficiency and CF-related diabetes had fewer negative results (P<0.05 for both). Negative results were more common in older CF patients (P<0.05). Use of antibiotics, presence of fungi in sputum and CF liver disease did not impact BDG levels. In conclusion, patients with CF experience significant BDG antigenaemia in the absence of IFD.

PMID: 28622948 [PubMed - as supplied by publisher]

Effect of acute predation with bacteriophage on intermicrobial aggression by Pseudomonas aeruginosa.

PLoS One. 2017;12(6):e0179659

Authors: Secor PR, Sass G, Nazik H, Stevens DA

Abstract
In persons with structural lung disease, particularly those with cystic fibrosis (CF), chronic airway infections cause progressive loss of lung function. CF airways can be colonized by a variety of microorganisms; the most frequently encountered bacterial and fungal pathogens are Pseudomonas aeruginosa and Aspergillus fumigatus, respectively. Co-infection with P. aeruginosa and A. fumigatus often results in a more rapid loss of lung function, indicating that interactions between these pathogens affect infection pathogenesis. There has been renewed interest in the use of viruses (bacteriophage, mycoviruses) as alternatives to antibiotics to treat these infections. In previous work, we found that filamentous Pf bacteriophage produced by P. aeruginosa directly inhibited the metabolic activity of A. fumigatus by binding to and sequestering iron. In the current study, we further examined how filamentous Pf bacteriophage affected interactions between P. aeruginosa and A. fumigatus. Here, we report that the antifungal properties of supernatants collected from P. aeruginosa cultures infected with Pf bacteriophage were substantially less inhibitory towards A. fumigatus biofilms. In particular, we found that acute infection of P. aeruginosa by Pf bacteriophage inhibited the production of the virulence factor pyoverdine. Our results raise the possibility that the reduced production of antimicrobials by P. aeruginosa infected by Pf bacteriophage may promote conditions in CF airways that allow co-infection with A. fumigatus to occur, exacerbating disease severity. Our results also highlight the importance of considering how the use of bacteriophage as therapeutic agents could affect the behavior and composition of polymicrobial communities colonizing sites of chronic infection.

PMID: 28622385 [PubMed - in process]

Increased immunogenicity and protective efficacy of the P. aeruginosa vaccine in mice using an alum and de-O-acylated lipooligosaccharide adjuvant system.

J Microbiol Biotechnol. 2017 Jun 16;:

Authors: Ryu JI, Wui SR, Ko A, Lee YJ, Do HTT, Kim HJ, Rhee IM, Park SA, Kim KS, Cho YJ, Lee NG

Abstract
Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that commonly causes fatal infections in cystic fibrosis and burn patients as well as in patients who are hospitalized or have impaired immune systems. P. aeruginosa infections are difficult to treat due to the high resistance of the pathogen to conventional antibiotics. Despite several efforts, no effective prophylactic vaccines against P. aeruginosa are currently available. In this study, we investigated the activity of the CIA06 adjuvant system, which is comprised of alum and de-O-acylated lipooligosaccharide, on a P. aeruginosa outer membrane protein (OMP) antigen vaccine in mice. The results indicated that CIA06 significantly increased the antigen-specific IgG titers and opsonophagocytic activity of immune sera against P. aeruginosa. In addition, the antibodies induced by the CIA06-adjuvanted vaccine exhibited higher cross-reactivity with heterologous P. aeruginosa strains. Finally, mice immunized with the CIA06-adjuvanted vaccine were effectively protected from lethal P. aeruginosa challenge. Based on these data, we suggest that the CIA06 adjuvant system might be used to promote the immunogenicity and protective efficacy of the P. aeruginosa OMP vaccine.

PMID: 28621112 [PubMed - as supplied by publisher]

A novel homozygous complex deletion in CFTR caused cystic fibrosis in a Chinese patient.

Mol Genet Genomics. 2017 Jun 15;:

Authors: Liu K, Liu Y, Li X, Xu KF, Tian X, Zhang X

Abstract
Cystic fibrosis (CF) is the most frequent lethal genetic disorder among Caucasians, but is considered to be a very rare disease in Chinese population. Here, we present an 11-year-old Chinese CF patient with disseminated bronchiectasis and salty sweat, for whom exon sequencing followed by multiplex ligation-dependent probe amplification analysis of the CFTR gene was applied for mutation screening. A homozygous deletion involving exon 20 of CFTR was observed in the patient's genome. Molecular characterization of the breakpoints indicated that both alleles of this locus had an identical novel complex rearrangement (c.3140-454_c.3367+249del931ins13, p.R1048_G1123del), leading to an in-frame removal of 76 amino acid residues in the second transmembrane domains of the CFTR protein. Although a same haplotype containing this complex rearrangement was observed on both of the maternal and paternal alleles, the parents denied any blood relationship as far as they know. Genome-wide homozygosity mapping was performed through SNP microarray and only a single homozygous interval of ~14.1 Mb at chromosome 7 containing the CFTR gene was observed, indicating the possible origin of the deletion from a common ancestor many generations ago. This study expands the mutation spectrum of CFTR in patients of Chinese origin and further emphasizes the necessity of MLPA analysis in mutation screening for CF patients.

PMID: 28620757 [PubMed - as supplied by publisher]

Postnatal Airway Growth in Cystic Fibrosis Piglets.

J Appl Physiol (1985). 2017 Jun 15;:jap.00263.2017

Authors: Adam RJ, Abou Alaiwa MH, Bouzek DC, Cook DP, Gansemer ND, Taft PJ, Powers LS, Stroik MR, Hoegger MJ, McMenimen JD, Hoffman EA, Zabner J, Welsh MJ, Meyerholz DK, Stoltz DA

Abstract
Mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel cause cystic fibrosis (CF). The leading cause of death in the CF population is lung disease. Increasing evidence suggests that in utero airway development is CFTR-dependent and that developmental abnormalities may contribute to CF lung disease. However, relatively little is known of postnatal CF airway growth, largely because such studies are limited in people. Therefore, we examined airway growth and lung volume in a porcine model of CF. We hypothesized that CF pigs would have abnormal postnatal airway growth. To test this hypothesis, we performed CT-based airway and lung volume measurements in three-week-old non-CF and CF pigs. We found that three-week-old CF pigs had tracheas of reduced caliber and irregular shape. Their bronchial lumens were reduced in size proximally but not distally, were irregularly shaped, and had reduced distensibility. Our data suggest that lack of CFTR results in aberrant postnatal airway growth and development, which could contribute to CF lung disease pathogenesis.

PMID: 28620056 [PubMed - as supplied by publisher]