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The prospect of gene therapy for inherited and acquired respiratory disease has energized the research community since the 1980s, with cystic fibrosis, as a monogenic disorder, driving early efforts to develop effective strategies. The fact that there are still no approved gene therapy products for the lung, despite many early phase clinical trials, illustrates the scale of the challenge: In the 1990s, first-generation non-viral and viral vector systems demonstrated proof-of-concept but low efficacy. Since then, there has been steady progress toward improved vectors with the capacity to overcome at least some of the formidable barriers presented by the lung. In addition, the inclusion of features such as codon optimization and promoters providing long-term expression have improved the expression characteristics of therapeutic transgenes. Early approaches were based on gene addition, where a new DNA copy of a gene is introduced to complement a genetic mutation: however, the advent of RNA-based products that can directly express a therapeutic protein or manipulate gene expression, together with the expanding range of tools for gene editing, has stimulated the development of alternative approaches. This review discusses the range of vector systems being evaluated for lung delivery; the variety of cargoes they deliver, including DNA, antisense oligonucleotides, messenger RNA (mRNA), small interfering RNA (siRNA), and peptide nucleic acids; and exemplifies progress in selected respiratory disease indications.

Background CF is traditionally assessed in clinic. It is unclear if home monitoring of young people with CF is feasible or acceptable. The COVID-19 pandemic has made home monitoring more of a necessity. We report the results of CLIMB-CF, exploring home monitoring's feasibility and potential obstacles. Methods We designed a mobile app and enrolled participants with CF aged 2-17 years and their parents for six months. They were asked to complete a variety of measures either daily or twice a week. During the study, participants and their parents completed questionnaires exploring depression, anxiety and quality of life. At the end of the study parents and participants completed acceptability questionnaires. Results 148 participants were recruited, 4 withdrew prior to starting the study. 82 participants were female with median (IQR) age 7.9 (5.2-12 years). Median data completeness was 40.1% (13.6-69.9%) for the whole cohort; when assessed by age participants aged ≥ 12 years contributed significantly less (15.6% [9.8-30%]). Data completeness decreased over time. There was no significant difference between parental depression and anxiety scores at the start and the end of the study nor in CFQ-R respiratory domain scores for participants ≥ 14 years. The majority of participants did not feel the introduction of home monitoring impacted their daily lives. Conclusions Most participants felt home monitoring did not negatively impact their lives and it did not increase depression, anxiety or decrease quality of life. However, uptake was variable, and not well sustained. The teenage years pose a particular challenge and further work is required.

Multiple-breath washout (MBW) can be performed with different gases (sulfur hexafluoride (SF6­) and nitrogen (N2)) and different devices, all of which give discrepant results. This study aimed to confirm previously reported differences and explore factors influencing discrepant results; equipment factors or the physical properties of gases used. Methods Healthy controls (HCs) and participants with cystic fibrosis (CF) completed MBW trials on two commercially available devices (Exhalyzer D (N2) and Innocor (SF6)). Simultaneous washout of both gases at the same time on the commercial equipment and simultaneous washouts using a respiratory mass spectrometer (RMS) were completed in subsets. Primary outcomes were lung clearance index (LCI), breath number and time required to washout. Results Breath number was higher with N2 washout than SF6 in both HCs and patients with CF, whether washouts were completed individually or simultaneously. The difference was greater in more advanced disease, largely caused by differences in the final part of the washout. Results from commercial devices were similar to those obtained with the RMS. Conclusions N2 MBW results were higher than SF6 MBW, with some of the largest differences reported to date being observed. The biggest impact was at the end of the washout and this was even the case when gases were washed out simultaneously. N2 and SF6 MBW results are inherently different and should be considered as independent measurements., Inherent differences in simultaneous SF6 and N2 washout on the mass spectrometer show why results are never comparable http://bit.ly/34k52Oo

BackgroundImpaired alveolar fluid clearance, determined in part by alveolar sodium transport, is associated with acute respiratory distress syndrome (ARDS). Nasal sodium transport may reflect alveolar transport. The primary objective of this prospective, observational study was to determine if reduced nasal sodium transport, as measured by nasal potential difference (NPD), was predictive of the development of and outcome from ARDS.MethodsNPD was measured in 15 healthy controls and in 88 patients: 40 mechanically ventilated patients defined as ‘at-risk’ for ARDS, 61 mechanically ventilated patients with ARDS (13 who were previously included in the ‘at-risk’ group) and 8 ARDS survivors on the ward.ResultsIn at-risk subjects, maximum NPD (mNPD) was greater in those who developed ARDS (difference –8.4 mV; 95% CI –13.8 to –3.7; p=0.005) and increased mNPD predicted the development of ARDS before its onset (area under the curve (AUC) 0.75; 95% CI 0.59 to 0.89). In the ARDS group, mNPD was not significantly different for survivors and non-survivors (p=0.076), and mNPD was a modest predictor of death (AUC 0.60; 95% CI 0.45 to 0.75). mNPD was greater in subjects with ARDS (−30.8 mV) than in at-risk subjects (−24.2 mV) and controls (−19.9 mV) (pConclusionsIncreased NPD predicts the development of ARDS in at-risk subjects but does not predict mortality. NPD increases before ARDS develops, is greater during ARDS, but is not significantly different for controls and survivors. These results may reflect the upregulated sodium transport necessary for alveolar fluid clearance in ARDS. NPD may be useful as a biomarker of endogenous mechanisms to stimulate sodium transport. Larger studies are now needed to confirm these associations and predictive performance.

The UK Respiratory Gene Therapy Consortium (GTC) The GTC was formed in 2001 from three groups at the Universities of Edinburgh and Oxford and Imperial College, London to explore gene therapy as a therapeutic option for people with cystic fibrosis (CF)1. The gene responsible for CF, Cystic Fibrosis Transmembrane conductance Regulator (CFTR), was identified in 19892 and over 2000 mutations are now known3, typically classified into six groups4. Whilst considerable progress has been made with this mutation-agnostic approach, gene therapy is not yet a clinical reality. In parallel, mutation-specific, small molecule CFTR modulator therapy has now demonstrated substantial clinical efficacy5. Here, we briefly summarise the opinions of the GTC on navigating this evolving terrain, as well as noting some opportunities for gene therapy in other respiratory diseases.

Thank you for the opportunity to respond to the correspondence by J.G. Nielsen from Innovision about our recent paper [1]. We would like to respond with a few points to address any concerns that may have arisen from his comments amongst colleagues at cystic fibrosis centres using the Exhalyzer D (Eco Medics, Dürnten, Switzerland)., Addressing concerns with use of the Exhalyzer D multiple breath washout device http://bit.ly/2ug0fAi

Rapid evaporative ionisation mass spectrometry (REIMS) is a novel technique for the real-time analysis of biological material. It works by conducting an electrical current through a sample, causing it to rapidly heat and evaporate, with the analyte containing vapour channelled to a mass spectrometer. It was used to characterise the metabolome of 45 Pseudomonas aeruginosa (P. aeruginosa) isolates from cystic fibrosis (CF) patients and compared to 80 non-CF P. aeruginosa. Phospholipids gave the highest signal intensity; 17 rhamnolipids and 18 quorum sensing molecules were detected, demonstrating that REIMS has potential for the study of virulence-related metabolites. P. aeruginosa isolates obtained from respiratory samples showed a higher diversity, which was attributed to the chronic nature of most respiratory infections. The analytical sensitivity of REIMS allowed the detection of a metabolome that could be used to classify individual P. aeruginosa isolates after repeated culturing with 81% accuracy, and an average 83% concordance with multilocus sequence typing. This study underpins the capacities of REIMS as a tool with clinical applications, such as metabolic phenotyping of the important CF pathogen P. aeruginosa, and highlights the potential of metabolic fingerprinting for fine scale characterisation at a sub-species level.

The major cause of lung damage in cystic fibrosis (CF) is infection with bacterial pathogens, the most prevalent of which is Pseudomonas aeruginosa (Pa), chronically infecting ∼60% patients by adolescence/adulthood (www.cysticfibrosis.org.uk/news/registry-report-2017). Pa may be successfully eradicated, but frequently recurs and establishes biofilms resistant to antibiotics/host defences [1]. Chronic Pa is closely linked with pulmonary exacerbation frequency, faster lung function decline and earlier mortality [2]. The huge antibiotic burden imposed upon patients and the resulting bacterial resistance, allergies and toxicities compound the detrimental impact of the infection itself. Chronic Pa should be avoided if at all possible; early detection and rapid treatment may be crucial in achieving this. Footnotes This manuscript has recently been accepted for publication in the European Respiratory Journal . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article. Conflict of interest: Dr. Davies reports other from Algipharma AS, other from Bayer AG, other from Boehringer Ingelheim Pharma GmbH & Co. KG, other from Galapagos NV, other from ImevaX GmbH, other from Nivalis Therapeutics, Inc., other from ProQR Therapeutics III B.V., other from Proteostasis Therapeutics, INC., other from Raptor Pharmaceuticals, Inc, other from Vertex Pharmaceuticals (Europe) Limited, other from Enterprise, other from Novartis, other from Pulmocide, other from Flatley, other from Nivalis Therapeutics Inc., grants from CF Trust, other from Teva, outside the submitted work. Conflict of interest: Dr. Alton has nothing to disclose. Conflict of interest: Dr. Simbo has nothing to disclose. Conflict of interest: Mr. Murphy has nothing to disclose. Conflict of interest: Dr. Seth has nothing to disclose. Conflict of interest: Dr. Williams has nothing to disclose. Conflict of interest: Mark Somerville has nothing to disclose. Conflict of interest: Dr. Jolly has nothing to disclose. Conflict of interest: Dr. Morant has nothing to disclose. Conflict of interest: Dr. Guest has nothing to disclose.

This chapter describes the therapeutic strategies for cystic fibrosis which are based on targeting cystic fibrosis transmembrane conductance regulator (CFTR), either at the gene or protein level. We provide updates on small molecule CFTR modulators and gene therapy, focusing on clinical development and evaluation. The field has seen significant progress over recent years, particularly with the CFTR potentiator, ivacaftor, in patients with class III mutations. Increased understanding of the abnormalities in the structure and function of CFTR protein will help optimize the approaches required for normalizing function and, in doing so, aid the rational design of clinical trials—both in terms of the development of more efficacious drugs and the selection of appropriate patient populations. While progress with gene therapy remains some way behind, potential benefits (including being mutation agnostic and a nonsystemic route of delivery) remain significant. It may be that future optimal approaches will harness the benefits of more than one of these approaches and lead to considerable synergy. The ultimate goal for molecular and advanced therapies in cystic fibrosis is to find drugs or combinations of drugs capable of restoring CFTR function, applicable to patients with any genetic mutation.

Antibiotic treatment for Pseudomonas aeruginosa (Pa) in cystic fibrosis is limited in efficacy and may lead to multi-drug resistance (MDR). Alternatives such as bacteriophages are being explored but well designed, and controlled trials are crucial. The rational selection of patients with bacteriophage susceptible infections is required for both safety and efficacy monitoring. We questioned whether bacteriophage susceptibility profiles were constant or variable over time, variability having been reported with antibiotics. Serial Pa isolates (n = 102) from 24 chronically infected cystic fibrosis (CF) patients over one year were investigated with plaque and antibiotic disc diffusion assays. Variable number tandem repeat (VNTR) analysis identified those patients with &gt, 1 isolate. A median (range) of 4 (3–6) isolates/patient were studied. Twenty-one (87.5%) individuals had a single VNTR type, three (12.5%) had two VNTR types at different times. Seventy-five percent of isolates were sensitive to bacteriophage at ≥ 1 concentration, 50% of isolates were antibiotic multidrug resistant. Serial isolates, even when representing a single VNTR type, varied in sensitivity to both bacteriophages and antibiotics. The rates of sensitivity to bacteriophage supports the development of this therapy, however, the variability in response has implications for the selection of patients in future trials which must be on the basis of current, not past, isolate testing.

Pseudomonas aeruginosa (Pa) infection is a major cause of airway inflammation in immunocompromised and cystic fibrosis (CF) patients. Mitogen-activated protein (MAP) and tyrosine kinases are integral to inflammatory responses and are therefore potential targets for novel anti-inflammatory therapies. We have determined the involvement of specific kinases in Pa-induced inflammation. The effects of kinase inhibitors against p38MAPK, MEK 1/2, JNK 1/2, Syk or c-Src, a combination of a p38MAPK with Syk inhibitor, or a novel narrow spectrum kinase inhibitor (NSKI), were evaluated against the release of the proinflammatory cytokine/chemokine, IL-6 and CXCL8 from BEAS-2B and CFBE41o- epithelial cells by Pa. Effects of a Syk inhibitor against phosphorylation of the MAPKs were also evaluated. IL-6 and CXCL8 release by Pa were significantly inhibited by p38MAPK and Syk inhibitors (p

Since identification of the CFTR gene over 25 years ago, gene therapy for cystic fibrosis (CF) has been actively developed. More recently gene therapy has been joined by other forms of "genetic medicines" including mRNA delivery, as well as genome editing and mRNA repair-based strategies. Proof-of-concept that gene therapy can stabilize the progression of CF lung disease has recently been established in a Phase IIb trial. An early phase study to assess the safety and explore efficacy of CFTR mRNA repair is ongoing, while mRNA delivery and genome editing-based strategies are currently at the pre-clinical phase of development. This review has been written jointly by some of those involved in the various CF "genetic medicine" fields and will summarize the current state-of-the-art, as well as discuss future developments. Where applicable, it highlights common problems faced by each of the strategies, and also tries to highlight where a specific strategy may have an advantage on the pathway to clinical translation. We hope that this review will contribute to the ongoing discussion about the hype versus reality of genetic medicine-based treatment approaches in CF. Pediatr Pulmonol. 2016;51:S5-S17. © 2016 Wiley Periodicals, Inc.

Detecting P. aeruginosa infection is problematic; breath analysis shows promise but requires optimisation http://ow.ly/WE1H2

Autoimmune pulmonary alveolar proteinosis (aPAP) is a lung disease characterised by the progressive accumulation of surfactant, leading to respiratory failure, due to anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) auto-antibodies. The standard of care is whole lung lavage (WLL) resulting in temporary remission of symptoms. This procedure is not only highly invasive but also needs to be performed repeatedly, carries risks and can solely be performed in highly-specialised centres. Administration of recombinant GM-CSF outcompetes the auto-GM-CSF antibodies and stimulates clearance of pulmonary surfactant by alveolar macrophages. However, this treatment is expensive, needs to be nebulised frequently and is not available to all patients. Therefore, we hypothesised that rSIV.F/HN, a lentiviral vector specifically pseudotyped for efficient gene transfer to the respiratory epithelium, carrying (m)GM-CSF cDNA, may be of therapeutic benefit. We were able to produce high-titer rSIV.F/HN carrying murine (m)GM-CSF (≥1e9 TU/ml) using scalable, serum-free suspension cultures. As previously shown, vector transduction of A549 cells (MOI 0.1–1000) led to a dose-related expression of mGM-CSF which, compared to recombinant mGM-CSF protein, showed similar activity in a mouse myeloid FDC-P1 cell proliferation assay. Transduction of air-liquid interface cultures (MOI 185), an ex vivo human model, resulted in stable, long-term (7 months) expression of mGM-CSF (n=6) (Mean 230.3 pg/ml). More recently, characterisation of a GM-CSF-knockout mouse showed that the model recapitulates the human disease phenotype, with significantly (p

We have shown that a lentiviral vector (rSIV.F/HN) pseudotyped with the F and HN proteins from Sendai virus generates high levels of intracellular proteins after lung transduction. Here, we evaluate the use of rSIV.F/HN for production of secreted proteins. We assessed whether rSIV.F/HN transduction of the lung generates therapeutically relevant levels of secreted proteins in the lung and systemic circulation using human α1-anti-trypsin (hAAT) and factor VIII (hFVIII) as exemplars. Sedated mice were transduced with rSIV.F/HN carrying either the secreted reporter gene Gaussia luciferase or the hAAT or hFVIII cDNAs by nasal sniffing. rSIV.F/HN-hAAT transduction lead to therapeutically relevant hAAT levels (70 μg/ml) in epithelial lining fluid, with stable expression persisting for at least 19 months from a single application. Secreted proteins produced in the lung were released into the circulation and stable expression was detectable in blood. The levels of hFVIII in murine blood approached therapeutically relevant targets. rSIV.F/HN was also able to produce secreted hAAT and hFVIII in transduced human primary airway cells. rSIV.F/HN transduction of the murine lungs leads to long-lasting and therapeutically relevant levels of secreted proteins in the lung and systemic circulation. These data broaden the use of this vector platform for a large range of disease indications.

BACKGROUND: Vitamin D has health benefits in many respiratory diseases but the evidence in CF is unclear. Induction of the antimicrobial peptides cathelicidin (LL37) and human-beta-defensin-2 (HBD-2) may be the mechanism of any benefit. We hypothesised that antimicrobial peptide levels would be decreased, and airway infection and inflammation greater, in CF children with vitamin D deficiency. The objective of the study was to explore relationships between vitamin D, LL37 and HBD-2, and airway infection, inflammation and physiology in children with CF. METHODS: Bronchoalveolar lavage (BALF) and blood were obtained from children undergoing fibreoptic bronchoscopy. Serum vitamin D, BALF HBD-2 and LL37, cultured bacteria and inflammatory markers were measured. Clinical parameters were recorded. RESULTS: 113 patients with CF, 23 with non-CF chronic suppurative lung disease (CSLD) and 6 healthy controls were included. We found no relationship between serum vitamin D and BALF HBD-2 or LL-37. There were no differences in infective or inflammatory markers between vitamin D sufficient and deficient groups. Vitamin D deficient patients (

To the Editor: The vast majority of treatments for cystic fibrosis (CF) target the downstream consequences of the disease and are incompletely effective. The success of the CF transmembrane conductance regulator (CFTR) potentiator ivacaftor has illustrated the clinical benefits arising from restoration of CFTR protein function (1). This agent is applicable as a monotherapy for a minority of patients with specific, rare mutations. CFTR gene therapy, a mutation-independent alternative, has demonstrated proof of principle for gene transfer in animal models and human trials, but only one study (using a viral vector) has unsuccessfully assessed whether clinical outcomes can be improved (2). In preparation for a phase IIb clinical trial of repeatedly administered, nonviral, liposome-mediated CFTR gene transfer assessing clinically meaningful outcomes (3), the UK CF Gene Therapy Consortium (www.cfgenetherapy.org.uk) undertook a single-application safety and dose-ranging study (NCT00789867). Some of the results of these studies have been previously reported in the form of abstracts (4, 5). The chosen plasmid DNA expresses CFTR under the control of the human cytomegalovirus enhancer/elongation factor 1α sequence (6), a modified EF1a promoter aiming for extended duration of expression (7), and was rendered CpG-free to minimize a host inflammatory response (6). The cationic lipid, GL67A, was chosen on the basis of extensive preclinical testing (8). After informed consent, adult patients with CF received a single nebulized +/− nasal dose of pGM169/GL67A. Reconstitution and preparation of pGM169/GL67A was undertaken on the day, and doses were delivered in sealed negative-pressure cubicles after pretreatment with inhaled salbutamol (albuterol). Preplanned adjunctive therapies including ibuprofen, prednisolone, or paracetamol were administered to some patients. The primary outcome of the clinical study was safety; assessment included examination, standard hematology/biochemistry, adverse events, spirometry, lung clearance index, chest computed tomography scan, gas transfer, bronchial biopsy histology, and immune markers. pGM169-specific DNA and mRNA were measured on nasal and lower airway brushings, with potential difference also measured bronchoscopically and nasally. For the latter, “responders” were defined as demonstrating chloride secretion 5 mV or more greater than their mean predose value, and greater than any of their predose responses. A total of 35 subjects (Tables 1 and ​and2)2) received a nebulized dose (5 ml, n = 8; 10 ml, n = 10; 20 ml, n = 17) via an AeroEclipse II (Trudell Medical International, London, ON, Canada) breath-actuated nebulizer (9). Three subjects undertook slow delivery (∼75 vs. 25 min for each 5 ml). Standard spray devices were used for nasal delivery (2 ml, n = 21). According to pre-/post-device weighing, a mean (SD) of 88.7% (2.9%) of expected nebulized dose and 94.5% (15.0%) of expected nasal dose was delivered. There were two serious adverse events: one occurred after the predosing bronchoscopy (swelling of the uvula related to intubation) and led to observation overnight in hospital, and the other was an episode of pancreatitis occurring around Day 10 after dosing (10 ml nebulized cohort). The subject was exocrine pancreatic sufficient and had likely experienced previous similar, but undiagnosed, episodes. Table 1. Baseline Demographics Table 2. Postdosing Responses Overall, in the trial, 94.3% of subjects experienced at least one adverse event, the majority of which were mild to moderate in severity and resolved spontaneously or with standard antipyretics. The most common occurred on the day of dosing and largely resolved within 24–48 hours (Tables 1 and ​and2):2): Typically, within the first few hours after dosing, a mild, self-limiting influenza-like systemic response was seen, most frequently in the 20-ml patients. This was not affected by slow delivery or coadministration of ibuprofen or prednisolone but was clearly dose-related and reduced by paracetamol. Symptoms of headache and/or tiredness were reported by 82, 70, and 13%, and raised serum inflammatory markers were recorded in 100, 60, and 63% of the 20-, 10-, and 5-ml groups respectively, with dose-related trends in maximal values. No patient dosed with 5 ml had a temperature higher than 38°C (Table 2). A relatively asymptomatic, dose-related, restrictive drop in spirometry was also observed, with no change in respiratory rate or oxygen saturation. No patient dosed with 5 ml showed a more than 20% relative fall in FEV1 (Table 2). The 20-ml group showed a small, significant (P

A key challenge in pulmonary gene therapy for cystic fibrosis is to provide long-term correction of the genetic defect. This may be achievable by targeting airway epithelial stem/progenitor cells with an integrating vector. Here, we evaluated the ability of a lentiviral vector, derived from the simian immunodeficiency virus and pseudotyped with F and HN envelope proteins from Sendai virus, to transduce progenitor basal cells of the mouse nasal airways. We first transduced basal cell-enriched cultures ex vivo and confirmed efficient transduction of cytokeratin-5 positive cells. We next asked whether progenitor cells could be transduced in vivo. We evaluated the transduction efficiency in mice pretreated by intranasal administration of polidocanol to expose the progenitor cell layer. Compared to control mice, polidocanol treated mice demonstrated a significant increase in the number of transduced basal cells at 3 and 14 days post vector administration. At 14 days, the epithelium of treated mice contained clusters (4 to 8 adjacent cells) of well differentiated ciliated, as well as basal cells suggesting a clonal expansion. These results indicate that our lentiviral vector can transduce progenitor basal cells in vivo, although transduction required denudation of the surface epithelium prior to vector administration.

Introduction: Patients with PCD typically suffer from rhinosinusitis. Despite the negative impact of nasal symptoms on quality of life there has been no nasal cavity inflammation research in this cohort. We aimed to identify whether PCD patients have increased levels of inflammatory cytokines in the nasal cavity compared to patients with cystic fibrosis (CF) and controls. Methods: Nasal mucosal lining fluid was collected (n= 50 PCD, 7 CF, 22 control) using nasosorption (NS) and analysed for inflammatory cytokines. Nasal swabs were performed for bacterial culture (n= 43 PCD). To assess ex vivo inflammatory response to controlled bacterial challenge, nasal brushings (n= 10 PCD, 10 CF, 18 control) were infected for 1 hour with Haemophilus influenzae, Pseudomonas aeruginosa or Staphylococcus aureus, the supernatant analysed for IL-8 at 1 and 24 hours post infection and compared with uninfected controls. Results: PCD patients had significantly higher NS levels of IL- 1β, IL-2, IL-6, IL-10, TNFα and IFNγ than patients with CF and significantly higher levels of IL-6, IL-8, IL- 1β and TNFα than controls. 50% of PCD patients had a positive bacterial culture. This was associated with significantly higher levels of IL-6, IL- 1β and TNFα, compared to patients with no growth who had similar levels to controls. Ex vivo PCD nasal cells produced higher baseline levels of IL-8 compared to control and CF cells but had a blunted response to infection at 24 hours. Conclusions: PCD patients have elevated levels of inflammatory cytokines in the nasal cavity, which are associated with bacterial infection. Further investigation is needed to determine the cause of a blunted IL-8 response ex vivo.

Pseudomonas aeruginosa opportunistically infects the airways of patients with cystic fibrosis and causes significant morbidity and mortality. Initial infection can often be eradicated though requires prompt detection and adequate treatment. Intermittent and then chronic infection occurs in the majority of patients. Better detection of P. aeruginosa infection using biomarkers may enable more successful eradication before chronic infection is established. In chronic infection P. aeruginosa adapts to avoid immune clearance and resist antibiotics via efflux pumps, β-lactamase expression, reduced porins and switching to a biofilm lifestyle. The optimal treatment strategies for P. aeruginosa infection are still being established, and new antibiotic formulations such as liposomal amikacin, fosfomycin in combination with tobramycin and inhaled levofloxacin are being explored. Novel agents such as the alginate oligosaccharide OligoG, cysteamine, bacteriophage, nitric oxide, garlic oil and gallium may be useful as anti-pseudomonal strategies, and immunotherapy to prevent infection may have a role in the future. New treatments that target the primary defect in cystic fibrosis, recently licensed for use, have been associated with a fall in P. aeruginosa infection prevalence. Understanding the mechanisms for this could add further strategies for treating P. aeruginosa in future.

The principal cause of morbidity and mortality in cystic fibrosis (CF) is pulmonary disease, so the focus of new treatments in this condition is primarily targeted at the lungs. Since the cloning of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene in 1989, there has been significant interest in the possibility of gene therapy as a treatment for CF. Early studies using viral vectors carrying a healthy CFTR plasmid highlighted the difficulties with overcoming the body's host defences. This article reviews the work on gene therapy in CF to date and describes the ongoing work of the UK CF Gene Therapy Consortium in investigating the potential of gene therapy as a treatment for patients with CF.

For gene therapy to improve lung function in cystic fibrosis (CF) subjects, repeated administration of the gene transfer agent over the lifetime of patients is likely to be necessary. This requirement limits the utility of adenoviral and adeno-associated viral vectors (both previously evaluated in CF gene therapy trials) because of induced adaptive immune responses that render repeated dosing ineffective. For CF gene therapy trials, non-viral vectors are currently the only viable option. We previously showed that the cationic lipid formulation GL67A is the most efficient of several non-viral vectors analysed for airway gene transfer. Here, we assessed the efficacy and safety of administering 12 inhaled doses of GL67A complexed with pGM169, a CpG-free plasmid encoding human CFTR complementary DNA, into mice. We show that repeated administration of pGM169/GL67A to murine lungs is feasible, safe and achieves reproducible, dose-related and persistent gene expression (>140 days after each dose) using an aerosol generated by a clinically relevant nebuliser. This study supports progression into the first non-viral multidose lung trial in CF patients. © 2014 Macmillan Publishers Limited.

Background: MBW data in cystic fibrosis (CF) have mainly been performed using SF 6 , but recent efforts have focussed on N 2 washout (WO). These different tracer gases give different results for unclear reasons. We performed MBW with both SF 6 and N 2 at the same time to investigate whether these differences were intrinsic to the gases or a feature of the different measurement technologies. Method: 8 healthy controls (HC) & 5 CF subjects completed at least 2 MBW trials on the Exhalyzer D (ExD/N 2 ) and Innocor (SF 6 ) attached in parallel. SF 6 was washed in to equilibrium (0.2% SF 6 in air) then SF 6 and resident N 2 were washed out (100% O 2 ) to 1/40 th of the starting concentration for each gas. Results were analysed using in house software for SF 6 (Simple WO, IGOR Pro) and Spiroware on ExD. Results: Both devices similarly discriminated in HC and CF. SF 6 WO decayed in a single exponential in HC, but 2 in CF. N 2 WO displayed 2 exponentials in HC, a longer tail to the WO curve in all cases. The first half of the WO was similar for both gases, separating beyond this. Gas concentration reached 1/40 th sooner in SF 6 than N 2 (HC 32.98±12.58 breaths in SF 6 vs. 47.89±13.97 in N 2 p=0.002 & CF 24.8 ± 8.72 vs. 59.5 ± 28.34 p=0.04). WO time (minutes) was lower in SF 6 (HC 2.5±0.59 vs. 3.34±0.78 p= Conclusions: There is a clear difference in the progression of N 2 and SF 6 throughout the WO, with this difference enhanced in disease. Results are being explored further to investigate whether the difference is due to innate nitrogen contribution or relates to offset in the derived gas signals within the devices.

Background: FRC is the volume of air left in lungs after a passive expiration, being influenced by lung compliance, also gas trapping and airway obstruction. Gold standard FRC is obtained using body plethysmography (FRC PLETH ) which captures all of the gas in the thorax. FRC from gas dilution methods (MBW) may be limited to communicating lung units so may be lower than FRC PLETH particularly in disease states. Debate within the field on the ideal MBW method is pertinent so accurate measures of FRC is vital. Methods: MBW trials with N 2 (FRC N2 ) (Exhalyzer D, Ecomedics AG) and SF 6 (FRC SF6 ) (Innocor TM Innovision) were performed on the same day, FRC PLETH was taken from the closest test from 11 Healthy Controls (HC) and 24 CF. Results: FRC was similar in HC with all measuring systems (FRC SF6 2.87 ± 0.48, FRC N2 3.09 ± 0.6, FRC PLETH 2.93 ± 0.49(NS)). However, in CF patients (FEV1% 76.1% ±17.18) FRC N2 was higher than FRC SF6 (p= N2 was similar to FRC PLETH p= >0.05; FRC SF6 was lower than FRC PLETH p= N2 2.41 ± 0.96, FRC SF6 1.89 ± 0.67, FRC PLETH 2.54 ± 0.85 (p= Conclusions: In HC FRC measurements are similar between devices, previous data suggest FRC PLETH should be higher than FRC from MBW but that was not the case here. In CF FRC PLETH is higher than FRC SF6 but not for FRC N2 . Thus, the FRC N2 may be giving a more accurate reflection of FRC than FRC SF6 ; we suggest using N 2 as a washout gas may enable contribution from poorly ventilated areas of lung not obtainable for the larger molecule SF 6 . More investigation is required, particularly where debate amongst MBW techniques is rife.

Introduction Cystic fibrosis (CF) is caused by mutations in the epithelial ion channel cystic fibrosis transmembrane conductance regulator (CFTR) gene but there is evidence that inflammation may alter CFTR function. We hypothesized that CFTR function may be impaired in subjects with primary ciliary dyskinesia (PCD), an inherited disorder of motile cilia associated with chronic airway inflammation. Objectives: We measured CFTR function using nasal potential difference (NPD) in subjects with PCD, CF and healthy controls (HC) and correlated NPD with markers of inflammation. Methods: 23 subjects (7 PCD, 8 CF and 8 HC) underwent NPD, nasal nitric oxide (nNO), sweat chloride, spirometry and CFTR genotyping. Nasosoprtion was performed using a synthetic absorptive matrix to collect nasal epithelial lining fluid (NLF) for the measurement of 9 cytokines. Results Median basal NPD values in PCD patients were similar to HC (-17 vs -24 mV, p 0.05). Cytokines were increased in PCD patients (p Conclusion PCD patients had reduced chloride secretion on NPD but this was not accompanied by evidence of sodium hyperabsorption. Results did not correlate with the increased nasal inflammation, although the study was small. More work is planned to establish whether this reflects CFTR dysfunction secondary to inflammation or is due to impaired epithelial integrity.

PURPOSE OF THE REVIEW: Since cloning of the disease-causing gene 27 years ago, the development of cystic fibrosis (CF) gene therapy has been pursued. Here, we will summarize key findings with a particular focus on recent developments. RECENT FINDINGS: Almost 3 decades of research have highlighted the complexity of lung gene transfer and have generated a body of data that has recently led to the completion of a large phase IIB study. This trial has, for the first time, shown that nonviral gene transfer can, albeit modestly, stabilize lung function in CF and provides the impetus for further development of more potent gene transfer agents. Lentiviral vectors, specifically pseudotyped to enable entry into airway epithelial cells have most recently been developed. Persistent expression after a single dose and the ability to be administered repeatedly suggest that these viral vectors hold promise for the treatment of CF; a first-in-man clinical trial will shortly be initiated. SUMMARY: Although the development of CF gene therapy has been slower than initially anticipated, recent progress has been encouraging and has renewed the interest of academics and industry to pursue lung gene therapy.

The potential for gene therapy to be an effective treatment for cystic fibrosis has been hampered by the limited gene transfer efficiency of current vectors. We have shown that recombinant Sendai virus (SeV) is highly efficient in mediating gene transfer to differentiated airway epithelial cells, because of its capacity to overcome the intra- and extracellular barriers known to limit gene delivery. Here, we have identified a novel method to allow the cystic fibrosis transmembrane conductance regulator (CFTR) cDNA sequence to be inserted within SeV (SeV-CFTR). Following in vitro transduction with SeV-CFTR, a chloride-selective current was observed using whole-cell and single-channel patch-clamp techniques. SeV-CFTR administration to the nasal epithelium of cystic fibrosis (CF) mice (Cftr(G551D) and Cftr(tm1Unc)TgN(FABPCFTR)#Jaw mice) led to partial correction of the CF chloride transport defect. In addition, when compared to a SeV control vector, a higher degree of inflammation and epithelial damage was found in the nasal epithelium of mice treated with SeV-CFTR. Second-generation transmission-incompetent F-deleted SeV-CFTR led to similar correction of the CF chloride transport defect in vivo as first-generation transmission-competent vectors. Further modifications to the vector or the host may make it easier to translate these studies into clinical trials of cystic fibrosis.

Clinically effective gene therapy for Cystic Fibrosis has been a goal for over 20 years. A plasmid vector (pGM169) that generates persistent expression and reduced host inflammatory responses in mice has raised prospects for translation to the clinic. The UK CF Gene Therapy Consortium is currently evaluating long-term repeated delivery of pGM169 complexed with the cationic lipid GL67A in a large Multidose Trial. This regulatory-compliant evaluation of aerosol administration of nine doses of pGM169/GL67A at monthly intervals, to the sheep lung, was performed in preparation for the Multidose Trial. All sheep tolerated treatment well with no adverse effects on haematology, serum chemistry, lung function or histopathology. Acute responses were observed in relation to bronchoalveolar cellularity comprising increased neutrophils and macrophage numbers 1 day post-delivery but these increases were transient and returned to baseline. Importantly there was no cumulative inflammatory effect or lung remodelling with successive doses. Molecular analysis confirmed delivery of pGM169 DNA to the airways and pGM169-specific mRNA was detected in bronchial brushing samples at day 1 following doses 1, 5 and 9. In conclusion, nine doses of pGM169/GL67A were well tolerated with no significant evidence of toxicity that would preclude adoption of a similar strategy in CF patients. © 2013 Elsevier Ltd.

Alveolar type II (ATII) cell proliferation and differentiation are important mechanisms in repair following injury to the alveolar epithelium. KGF is a potent ATII cell mitogen, which has been demonstrated to be protective in a number of animal models of lung injury. We have assessed the effect of recombinant human KGF (rhKGF) and liposome-mediated KGF gene delivery in vivo and evaluated the potential of KGF as a therapy for acute lung injury in mice. rhKGF was administered intratracheally in male BALB/c mice to assess dose response and time course of proliferation. SP-B immunohistochemistry demonstrated significant increases in ATII cell numbers at all rhKGF doses compared with control animals and peaked 2 days following administration of 10 mg/kg rhKGF. Protein therapy in general is very expensive, and gene therapy has been suggested as a cheaper alternative for many protein replacement therapies. We evaluated the effect of topical and systemic liposome-mediated KGF-gene delivery on ATII cell proliferation. SP-B immunohistochemistry showed only modest increases in ATII cell numbers following gene delivery, and these approaches were therefore not believed to be capable of reaching therapeutic levels. The effect of rhKGF was evaluated in a murine model of OA-induced lung injury. This model was found to be associated with significant alveolar damage leading to severe impairment of gas exchange and lung compliance. Pretreatment with rhKGF 2 days before intravenous OA challenge resulted in significant improvements in Po2, Pco2, and lung compliance. This study suggests the feasibility of KGF as a therapy for acute lung injury.

Introduction: Since identification of the disease causing gene over 25 years ago, cystic fibrosis (CF) has been at the forefront of gene therapy research. Despite initial optimism, CF gene therapy has proven considerably more challenging than initially anticipated. However, research conducted over the past two decades has clarified the strength and weaknesses of viral and non-viral gene transfer agents for CF gene therapy.Areas covered: The older literature related to CF gene therapy has been reviewed in many publications and we will, therefore, restrict this review to a brief description and discussion of the key lessons learnt, instead focusing on more recent progress in the field which was identified through literature searches. This review will summarize research leading up to the recent pivotal proof-of-concept study showing that non-viral gene therapy can stabilize the decline of lung function in CF patients and also highlight recent advances in viral vector development which may overcome pr...

Pseudomonas aeruginosa is a remarkably versatile environmental bacterium with an extraordinary capacity to infect the cystic fibrosis (CF) lung. Infection with P. aeruginosa occurs early, and although eradication can be achieved following early detection, chronic infection occurs in over 60% of adults with CF. Chronic infection is associated with accelerated disease progression and increased mortality. Extensive research has revealed complex mechanisms by which P. aeruginosa adapts to and persists within the CF airway. Yet knowledge gaps remain, and prevention and treatment strategies are limited by the lack of sensitive detection methods and by a narrow armoury of antibiotics. Further developments in this field are urgently needed in order to improve morbidity and mortality in people with CF. Here, we summarize current knowledge of pathophysiological mechanisms underlying P. aeruginosa infection in CF. Established treatments are discussed, and an overview is offered of novel detection methods and therapeutic strategies in development.

As antibiotic resistance increases, there is a need for new therapies to treat infection, particularly in cystic fibrosis (CF), wherePseudomonas aeruginosais a ubiquitous pathogen associated with increased morbidity and mortality. Bacteriophages are an attractive alternative treatment, as they are specific to the target bacteria and have no documented side effects. The efficacy of phage cocktails was establishedin vitro. TwoP. aeruginosastrains were taken forward into an acute murine infection model with bacteriophage administered either prophylactically, simultaneously, or postinfection. The infective burden and inflammation in bronchoalveolar lavage fluid (BALF) were assessed at various times. With low infective doses, both control mice and those undergoing simultaneous phage treatment clearedP. aeruginosainfection at 48 h, but there were fewer neutrophils in BALF of phage-treated mice (median, 73.2 × 104/ml [range, 35.2 to 102.1 × 104/ml] versus 174 × 104/ml [112.1 to 266.8 × 104/ml],P< 0.01 for the clinical strain; median, 122.1 × 104/ml [105.4 to 187.4 × 104/ml] versus 206 × 104/ml [160.1 to 331.6 × 104/ml],P< 0.01 for PAO1). With higher infective doses of PAO1, all phage-treated mice clearedP. aeruginosainfection at 24 h, whereas infection persisted in all control mice (median, 1,305 CFU/ml [range, 190 to 4,700 CFU/ml],P< 0.01). Bacteriophage also reduced CFU/ml in BALF when administered postinfection (24 h) and both CFU/ml and inflammatory cells in BALF when administered prophylactically. A reduction in soluble inflammatory cytokine levels in BALF was also demonstrated under different conditions. Bacteriophages are efficacious in reducing both the bacterial load and inflammation in a murine model ofP. aeruginosalung infection. This study provides proof of concept for future clinical trials in patients with CF.

Background The nuclear membrane of differentiated airway epithelial cells is a significant barrier for nonviral vectors. Trans-cyclohexane-1,2-diol (TCHD) is an amphipathic alcohol that has been shown to collapse nuclear pore cores and allow the uptake of macromolecules that would otherwise be too large for nuclear entry. Previous studies have shown that TCHD can increase lipid-mediated transfection in vitro. Methods We aimed to reproduce these in vitro studies using the cationic lipid GL67A, which we are currently assessing in cystic fibrosis trials and, more importantly, we assessed the effects of TCHD on transfection efficiency in differentiated airway epithelium ex vivo and in mouse lung in vivo using three different drug delivery protocols (nebulisation and bolus administration of TCHD to the mouse lung, as well as perfusion of TCHD to the nasal epithelium, which prolongs contact time between the airway epithelium and drug). Results TCHD (0.5–2%) dose-dependently increased Lipofectamine 2000 and GL67A-mediated transfection of 293T cells by up to 2 logs. Encouragingly, exposure to 8% TCHD (but not 0.5% or 2.0%) increased gene expression in fully differentiated human air liquid interface cultures by approximately 20-fold, although this was accompanied by significant cell damage. However, none of the TCHD treated mice in any of the three protocols had higher gene expression compared to no TCHD controls. Conclusions Although TCHD significantly increases gene transfer in cell lines and differentiated airway epithelium ex vivo, this effect is lost in vivo and further highlights that promising in vitro findings often cannot be translated into in vivo applications. Copyright © 2012 John Wiley & Sons, Ltd.

Studies in cystic fibrosis (CF) generally focus on inflammation present in the airway lumen. Little is known about inflammation occurring in the airway wall, the site ultimately destroyed in end-stage disease.To test the hypothesis that inflammatory patterns in the lumen do not reflect those in the airway wall of children with CF.Bronchoalveolar lavage (BAL) fluid and endobronchial biopsies were obtained from 46 children with CF and 16 disease-free controls. BAL cell differential was assessed using May-Gruenwald-stained cytospins. Area profile counts of bronchial tissue immunopositive inflammatory cells were determined.BAL fluid from children with CF had a predominance of neutrophils compared with controls (median 810×10(3)/ml vs 1×10(3)/ml, p0.0001). In contrast, subepithelial bronchial tissue from children with CF was characterised by a predominance of lymphocytes (median 961 vs 717 cells/mm(2), p=0.014), of which 82% were (CD3) T lymphocytes. In chest exacerbations, BAL fluid from children with CF had more inflammatory cells of all types compared with those with stable disease whereas, in biopsies, only the numbers of lymphocytes and macrophages, but not of neutrophils, were higher. A positive culture of Pseudomonas aeruginosa was associated with higher numbers of T lymphocytes in subepithelial bronchial tissue (median 1174 vs 714 cells/mm(2), p=0.029), but no changes were seen in BAL fluid. Cell counts in BAL fluid and biopsies were positively correlated with age but were unrelated to each other.The inflammatory response in the CF airway is compartmentalised. In contrast to the neutrophil-dominated inflammation present in the airway lumen, the bronchial mucosa is characterised by the recruitment and accumulation of lymphocytes.

The "low volume hypothesis," stating that imbalanced ion movement across the cystic fibrosis (CF) airway epithelium leads to a reduction in periciliary fluid (PCL) and consequently impaired mucociliary clearance, has been the prevailing theory explaining CF pathophysiology, and has been supported by animal models and ex vivo cell culture systems. However, studies in freshly obtained human tissue have not yet been performed. Methods to quantify PCL height in freshly obtained airway biopsies may be useful to assess efficacy of new treatments aimed at restoring PCL height. Here, we established methods to quantify PCL height in freshly obtained CF and non-CF human lower airway biopsies. More than 90% of biopsies contained ciliated epithelium, and PCL height measurements were feasible in approximately 50% of these. Although the mean PCL height was reduced in CF tissue (non-CF, 5.60 ± 0.28 μm; CF, 4.52 ± 0.47 μm), this did not reach statistical significance (P = 0.06). To strengthen the data, we performed similar studies in wild-type and CF knockout mice, and confirmed the results (non-CF, 4.70 ± 0.13; CF, 4.10 ± 0.09 μm; P0.05). PCL height measurements in freshly obtained human airway biopsies are feasible, and PCL height appears reduced in subjects with CF, thereby further supporting the "low volume hypothesis." However, power calculations indicate that this assay can only be considered as a biomarker in large, late-phase clinical trials, because sample sizes required to achieve sufficient power are comparatively large.

The report of the first patients with cystic fibrosis (CF) to receive cystic fibrosis transmembrane conductance regulator gene (CFTR) therapy appeared in 1993, and since then there have been more than 20 clinical trials of both viral and nonviral gene transfer agents. These have largely been single dose to either nose or lower airway and have been designed around molecular or bioelectrical outcome measures. Both transgene mRNA and partial correction of chloride secretion have been reported, although sodium hyperabsorption has not been improved. The U.K. Cystic Fibrosis Gene Therapy Consortium is focused on a clinical program to establish whether these proof-of-principle measures translate into clinical benefit. Here, we review the published literature, discuss the limitations to gene therapy in the CF airway, and consider issues influencing the design of clinical trial programs.

We have previously shown that recombinant Sendai virus (SeV) vector, derived from murine parainfluenza virus, is one of the most efficient vectors for airway gene transfer. We have also shown that SeV-mediated transfection on second administration, although reduced by 60% when compared with levels achieved after a single dose, is still high because of the efficient transfection achieved by SeV vector in murine airways. Here, we show that these levels further decrease on subsequent doses. In addition, we validated SeV vector repeat administration in a non-natural host model, the sheep. As part of these studies we first assessed viral stability in a Pari LC Plus nebuliser, a polyethylene catheter (PEC) and the Trudell AeroProbe. We also compared the distribution of gene expression after PEC and Trudell AeroProbe administration and quantified virus shedding after sheep transduction. In addition, we show that bronchial brushings and biopsies, collected in anaesthetized sheep, can be used to assess SeV-mediated gene expression over time. Similar to mice, gene expression in sheep was transient and had returned to baseline values by day 14. In conclusion, the SeV vector should be strongly considered for lung-related applications requiring a single administration of the vector even though it might not be suitable for diseases requiring repeat administration.

Pulmonary disease is the most important cause of morbidity and mortality in cystic fibrosis (CF). Most patients with CF die from respiratory failure with extensive airway destruction. Airway remodelling, defined as structural airway wall changes, begins early in life in CF but the sequence of remodelling events in the disease process is poorly understood. Airway remodelling in CF has traditionally been thought to be solely the consequence of repeated cycles of inflammation and infection. However, new evidence obtained from developmental, physiological and histopathological studies suggests that there might instead be multiple mechanisms leading to airway remodelling in CF including (1) changes related to infection and inflammation; (2) changes specific to CF as a result of CF transmembrane conductance regulator (CFTR) dysfunction in the airway wall, independent of infection and inflammation; and (3) protective responses to (1) and/or (2). Recent advances in bronchoscopic techniques have allowed airway mucosal (endobronchial) biopsies to be taken in children and even infants. Endobronchial biopsy studies may provide insight into the role and relative contribution of the different mechanisms of airway remodelling in CF, with the main limitation that they assess only changes in proximal large airways and not in peripheral small airways from where CF disease is thought to originate. Findings from biopsy studies could encourage the development of novel therapeutic strategies targeting structural changes in addition to infection and inflammation.

Background When assessing the efficacy of gene transfer agents (GTAs) for cystic fibrosis (CF) gene therapy, we routinely evaluate gene transfer in the mouse nose and measure transfection efficiency by assessing transgene-specific mRNA using the real-time (TaqMan) quantitative reverse transcriptase-polymerase chain reaction. TaqMan is traditionally used to quantify expression in whole tissue homogenates, which in the nose would contain many cells types, including respiratory and olfactory epithelium. Only the respiratory epithelium is a satisfactory model for human airway epithelium and therefore CFTR gene transfer should be specifically assessed in respiratory epithelial cells (RECs). Methods We have compared laser microdissection, pronase digestion and nasal brushing for: (i) the ability to enrich RECs from the wild-type mouse nose and (ii) the length of time to perform the procedure. Using TaqMan, we subsequently assessed gene transfer in enriched RECs after nasal perfusion of GL67A/pCF1-CFTR complexes in a CF mouse model. Results Laser microdissection successfully isolated RECs; however, time-consuming sample preparation made this technique unsuitable for high-throughput studies. Pronase digestion was sufficiently rapid but only yielded 19% (range = 13%) RECs (n = 6). The nasal brushing method was superior, yielding 92% (range = 15%) RECs (n = 8) and was equally effective in CF knockout mice (91%, range = 14%, n = 10). Importantly, gene transfer was detectable in brushed RECs from 70% of perfused mice and the number of vector-specific transcripts was comparable to 3.5% of endogenous wild-type Cftr levels. Conclusions Isolation of RECs by brushing allows accurate assessment of GTA transfection efficiency in an experimental system that is relevant for CF gene therapy. Copyright © 2009 John Wiley & Sons, Ltd.

Although transfections are routinely used in the laboratory, the mechanism(s) by which exogenous DNA is transported into the nucleus is poorly understood. By improving our understanding of how vectors circumvent the numerous cellular barriers to gene transfer, more efficient gene delivery methods can be devised. We have begun to design plasmid constructs that enter the nucleus of specific cell types in the absence of cell division, thereby enhancing levels of expression. We have shown that inclusion of specific DNA sequences in plasmid constructs mediates nuclear import both in vitro and in vivo. Here, we use plasmid affinity chromatography, mass spectrometry (MS), and live-cell pulldowns of transfected plasmid constructs to identify protein cofactors that interact in a sequence-specific manner with these DNA nuclear targeting sequences (DTSs). Importin beta(1), importin 7, and the small guanosine triphosphatase Ran all demonstrate DTS-specific interaction in both MS and pull-down assays, consistent with our model of plasmid nuclear import. In addition, knockdown of importin beta(1) with small interfering RNA (siRNA) abrogates plasmid nuclear import, indicating that it is a necessary cofactor. Our discovery that specific karyopherins mediate plasmid nuclear import can be used to design more effective vectors for gene delivery.

BACKGROUND Mannose-binding lectin (MBL) deficiency has been associated with infections of the respiratory tract and with increased disease severity in cystic fibrosis (CF). The mechanism is uncertain, and could relate either to systemic or local effects. The aim of this study was to determine, in a large cohort of children, whether MBL is present on the airway surface in health or disease. METHODS Bronchoalveolar lavage (BAL) fluid from children with and without respiratory infection (some with underlying disease) was analysed for MBL and neutrophil elastase (NE). Levels were compared between groups, and correlations were examined with local and systemic inflammatory markers, infective organisms and load. RESULTS 85 children were recruited to the study. MBL was absent in the lavage of all 7 children without lung infection but present in 62% (8/13) of those with acute pneumonia/pneumonitis, 23% (5/22) with recurrent respiratory tract infections, 17% (1/6) with primary ciliary dyskinesia and 8% (3/37) with CF (p

Gene therapy is currently being developed for a wide range of acute and chronic lung diseases. The target cells, and to a degree the extra and intra-cellular barriers, are disease-specific and over the past decade the gene therapy community has recognized that no one vector is good for all applications, but that the gene transfer agent (GTA) has to be carefully matched to the specific disease target. Gene therapy is particularly attractive for diseases that currently do not have satisfactory treatment options and probably easier for monogenic disorders than for complex diseases. Cystic fibrosis (CF) fulfils these criteria and is, therefore, a good candidate for gene therapy-based treatment. This review will focus on CF as an example for lung gene therapy, but lessons learned may be applicable to other target diseases.

BackgroundFor cystic fibrosis (CF) patients there is a lack of good assays of disease activity and response to new therapeutic interventions, including gene therapy. Current measures of airways inflammation severity are insensitive or non-specific.MethodsBronchoalveolar lavage fluid from 39 CF children and 38 respiratory disease controls was obtained at bronchoscopy and analysed by surface enhanced laser desorption ionisation time of flight (SELDI-TOF) mass spectrometry. Recognized proteins were assessed for CF disease specificity. Individual protein identification of specific peaks was performed.Results1277 proteins/peptides, > 4 kDa, were detected using 12 different surfaces and binding conditions. 202 proteins/peptides were differentially expressed in the CF samples (p < 0.001), 167 up-regulated and 35 down-regulated. The most discriminatory biomarker had a mass of 5.163 kDa. The most abundant, with a mass of 10.6 kDa, was identified as s100 A8 (calgranulin A).ConclusionsThe application of SELDI-TOF mass spectrometry allows evaluation of proteins in BAL fluid avoiding the limitations of only analysing predetermined proteins and potentially identifying proteins not previously appreciated as biomarkers. Its application to cystic fibrosis should enable appropriate evaluation of evolving illness, of gene therapy and other new therapies.

It is not known whether the progressive airway changes in cystic fibrosis (CF) are all secondary to infection and inflammation. The CF mouse nose shares electrophysiologic and cellular properties with human CF airway epithelium. In the present work, we tested the hypothesis that structural abnormalities in the nasal mucosa of CF mice develop independent of infection and inflammation. We performed nasal lavage and subsequent serial coronal section through the nasal tissue of adult CF (mutations Cftr(TgHm1G551D) and Cftr(tm1Unc)-TgN((FABPCFTR))) and wild-type mice raised under normal housing conditions. Nasal tissue was also obtained from Day 17 embryos and newborn pups. Detailed histologic examination of the respiratory and olfactory epithelium within the nasal cavity was performed. Bacterial culture, cell count, and macrophage inflammatory protein-2 (MIP-2) concentration were assessed in nasal lavage fluid. Significantly thickened respiratory epithelium and increased mucous cell density was found in adult CF mice of both mutations compared with wild-type animals. In contrast, the olfactory epithelium was thinner, with a decreased cell density. Areas of lymphoid aggregates were found in CF mice but not in non-CF mice. There were no differences in bacterial growth, cell count, or MIP-2 concentrations. No genotype differences were observed in the embryonic or newborn periods. There are significant histologic changes in the nasal mucosa of adult CF mice, not associated with increased lumenal inflammation or bacterial content, and which are not present perinatally. These may be novel therapeutic targets.

A major limitation of many self-assembling nonviral gene transfer formulations is that they are commonly prepared at relatively low component concentrations. While this typically has little impact on their use in cell culture, it can severely limit the progress of in vivo studies. In order to overcome this, we have developed a simple, scalable, pharmaceutically acceptable concentration method that has allowed us to increase the concentration of a commonly used pDNA/PEI formulation from 0.2 to >8 mg/ml plasmid DNA (pDNA). Crucially, the concentration method was found to have only minimal impact on the electrostatic properties or size of the pDNA/PEI particles. When delivered as an aerosol to the mouse lung, the concentrated pDNA/PEI formulations resulted in a 15-fold increase in lung reporter gene expression, with minimal impact in terms of inflammation or toxicity. Importantly, this performance advantage was replicated after aerosol administration to sheep lungs, with reporter gene expression being similarly approximately 15-fold higher than with the conventional pDNA/PEI formulation, and lung inflammation falling to background levels. These findings demonstrate that concentrated pDNA/PEI formulations offer increased aerosol gene transfer with decreased inflammatory sequelae, and represent a promising advance in the field of nonviral lung gene transfer. It seems likely that similar benefits might be achievable with alternative delivery routes and with other nonviral formulations.

Structural alterations to airway smooth muscle (ASM) are a feature of asthma and cystic fibrosis (CF) in adults.We investigated whether increase in ASM mass is already present in children with chronic inflammatory lung disease.Fiberoptic bronchoscopy was performed in 78 children (median age [IQR], 11.3 [8.5-13.8] yr): 24 with asthma, 27 with CF, 16 with non-CF bronchiectasis (BX), and 11 control children without lower respiratory tract disease. Endobronchial biopsy ASM content and myocyte number and size were quantified using stereology.The median (IQR) volume fraction of subepithelial tissue occupied by ASM was increased in the children with asthma (0.27 [0.12-0.49]; P0.0001), CF (0.12 [0.06-0.21]; P0.01), and BX (0.16 [0.04-0.21]; P0.01) compared with control subjects (0.04 [0.02-0.05]). ASM content was related to bronchodilator responsiveness in the asthmatic group (r = 0.66, P0.01). Median (IQR) myocyte number (cells per mm(2) of reticular basement membrane) was 8,204 (5,270-11,749; P0.05) in children with asthma, 4,504 (2,838-8,962; not significant) in children with CF, 4,971 (3,476-10,057; not significant) in children with BX, and 1,944 (1,596-6,318) in control subjects. Mean (SD) myocyte size (mum(3)) was 3,344 (801; P0.01) in children with asthma, 3,264 (809; P0.01) in children with CF, 3,177 (873; P0.05) in children with BX, and 1,927 (386) in control subjects. In all disease groups, the volume fraction of ASM in subepithelial tissue was related to myocyte number (asthma: r = 0.84, P0.001; CF: r = 0.81, P0.01; BX: r = 0.95, P0.001), but not to myocyte size.Increases in ASM (both number and size) occur in children with chronic inflammatory lung diseases that include CF, asthma, and BX.