Infect Drug Resist. 2023 Aug 28;16:5627-5635. doi: 10.2147/IDR.S418969. eCollection 2023.

ABSTRACT

PURPOSE: Burkholderia cepacia complex (Bcc) is a known significant opportunistic pathogen causing morbidity and mortality, particularly in those with cystic fibrosis, chronic granulomatous disease, or immunocompromising host. Mortality of Bcc bloodstream infections among non-cystic fibrosis patients remained high. The antibiotic treatment for Bcc infection is quite challenging due to its intrinsic resistance to most antibiotics, and the resistance to carbapenems was the biggest concern among them. We aimed to realize the mechanism of carbapenem resistance in Bcc.

PATIENTS AND METHODS: Ten strains of Bcc were identified by the MALDI-TOF MS, and the drug susceptibility test was using VITEK 2 system. The Burkholderia cepacia complex genomes were sequenced via Nanopore GridIon. We also downloaded another ninety-five strains of Bcc from the National Center for Biotechnology Information database to evaluate the divergence between carbapenem-resistance and carbapenem-sensitive strains.

RESULTS: The genetic organization between carbapenem-sensitive and carbapenem-resistant strains of Bcc showed no difference. However, in the carbapenem-sensitive strain, E151V substitution in PenR was detected. In addition, a novel specific OXA family subgroup, blaOXA-1043 in Burkholderia cenocepacia was discovered.

CONCLUSION: The E151V substitution in PenR may be associated with carbapenem-sensitive in Bcc. Moreover, the V151E mutation in PenR may be related to the activation of PenB, leading to Bcc resistance to carbapenems. Besides, a novel OXA family subgroup, blaOXA-1043, was found in Burkholderia cenocepacia, which differs from the previous OXA family.

PMID:37662974 | PMC:PMC10473398 | DOI:10.2147/IDR.S418969

bioRxiv. 2023 Aug 21:2023.08.21.554169. doi: 10.1101/2023.08.21.554169. Preprint.

ABSTRACT

Chronic Pseudomonas aeruginosa lung infections are a distinctive feature of cystic fibrosis (CF) pathology, that challenge adults with CF even with the advent of highly effective modulator therapies. Characterizing P. aeruginosa transcription in the CF lung and identifying factors that drive gene expression could yield novel strategies to eradicate infection or otherwise improve outcomes. To complement published P. aeruginosa gene expression studies in laboratory culture models designed to model the CF lung environment, we employed an ex vivo sputum model in which laboratory strain PAO1 was incubated in sputum from different CF donors. As part of the analysis, we compared PAO1 gene expression in this "spike-in" sputum model to that for P. aeruginosa grown in artificial sputum medium (ASM). Analyses focused on genes that were differentially expressed between sputum and ASM and genes that were most highly expressed in sputum. We present a new approach that used sets of genes with correlated expression, identified by the gene expression analysis tool eADAGE, to analyze the differential activity of pathways in P. aeruginosa grown in CF sputum from different individuals. A key characteristic of P. aeruginosa grown in expectorated CF sputum was related to zinc and iron acquisition, but this signal varied by donor sputum. In addition, a significant correlation between P. aeruginosa expression of the H1-type VI secretion system and corrector use by the sputum donor was observed. These methods may be broadly useful in looking for variable signals across clinical samples.

IMPORTANCE: Identifying the gene expression programs used by Pseudomonas aeruginosa to colonize the lungs of people with cystic fibrosis (CF) will illuminate new therapeutic strategies. To capture these transcriptional programs, we cultured the common P. aeruginosa laboratory strain PAO1 in expectorated sputum from CF patient donors. Through bioinformatics analysis, we defined sets of genes that are more transcriptionally active in real CF sputum compared to artificial sputum media (ASM). Many of the most differentially active gene sets contained genes related to metal acquisition, suggesting that these gene sets play an active role in scavenging for metals in the CF lung environment which is inadequately represented in ASM. Future studies of P. aeruginosa transcription in CF may benefit from the use of an expectorated sputum model or modified forms of ASM supplemented with metals.

PMID:37662412 | PMC:PMC10473638 | DOI:10.1101/2023.08.21.554169

Lancet Respir Med. 2023 Aug 31:S2213-2600(23)00226-6. doi: 10.1016/S2213-2600(23)00226-6. Online ahead of print.

ABSTRACT

BACKGROUND: Mucociliary clearance is dysfunctional in people with primary ciliary dyskinesia, resulting in the accumulation of dehydrated mucus in the airways that is difficult to clear. We undertook a study to assess the benefit on lung function of treatment with a nebulised epithelial sodium channel (ENaC) blocker, idrevloride, with or without hypertonic saline, in people with primary ciliary dyskinesia.

METHODS: The CLEAN-PCD trial was a phase 2, randomised, double-blind, placebo-controlled crossover trial conducted at 32 tertiary adult and paediatric care centres and university hospitals in Canada, Denmark, Germany, Italy, the Netherlands, Poland, the UK, and the USA. People with a confirmed diagnosis of primary ciliary dyskinesia, aged 12 years or older, with a percentage of predicted FEV1 (ppFEV1) in the range of 40% to <90%, were randomly assigned in a 2:2:1:1 ratio (block size=6), stratified by ppFEV1 at screening, to one of four sequences: (1) idrevloride in hypertonic saline in treatment period 1 then hypertonic saline in treatment period 2; (2) hypertonic saline in treatment period 1 then idrevloride in hypertonic saline in treatment period 2; (3) idrevloride in treatment period 1 then placebo in treatment period 2; and (4) placebo in treatment period 1 then idrevloride in treatment period 2. The idrevloride dose was 85 μg and hypertonic saline was 4·2% NaCl. 3 mL of each study treatment was nebulised twice daily for 28 days in treatment periods 1 and 2; the two 28-day treatment periods were separated by a 28-day washout period. The primary endpoint was absolute change from baseline in ppFEV1 after 28 days. Safety assessments and reports of adverse events were made at clinic visits during each treatment period and by a follow-up telephone call 28 days after the last dose of study drug. Additionally, adverse events could be reported at a follow-up telephone call 3 days after the start of dosing and as they arose. Participants who received at least one dose of study drug were included in the safety analyses (safety set), and those who also had spirometry data were included in the efficacy analyses (full analysis set). The completed study is registered (EudraCT 2015-004917-26; ClinicalTrials.govNCT02871778).

FINDINGS: Between Sep 14, 2016, and May 31, 2018, 216 patients were screened and 123 were randomly assigned to one of four crossover sequences. Across the two treatment periods, treatment with idrevloride in hypertonic saline was initiated in 80 patients and completed in 78 patients (all 78 had data available and were included in the analysis); hypertonic saline initiated in 81 patients and completed in 76 patients (75 had data available and were included in the analysis); idrevloride initiated in 37 patients and completed in 35 patients (34 had data available and were included in the analysis); and placebo initiated in 36 patients and completed in 34 patients (all 34 had data available and were included in the analysis). Greater absolute increases in ppFEV1 from baseline to 28 days of treatment were seen with idrevloride in hypertonic saline (least-squares mean absolute change from baseline 1·0 percentage points, 95% CI -0·4 to 2·4) than with hypertonic saline alone (least-squares mean absolute change from baseline of -0·5 percentage points, -2·0 to 0·9; difference 1·5 percentage points, 95% CI <0·1 to 3·0; p=0·044). There was no significant difference in ppFEV1 for the parallel comparison of idrevloride in hypertonic saline compared with placebo or the crossover comparison of idrevloride with placebo. Adverse events were similar across treatments (57 to 65% of patients). Cough occurred in a greater proportion of participants during treatments that contained idrevloride or hypertonic saline compared with placebo, and oropharyngeal pain occurred in a greater proportion of participants during idrevloride treatments than during treatment with hypertonic saline alone or placebo, whereas chest discomfort was more common during treatments that included hypertonic saline.

INTERPRETATION: In this phase 2 crossover study, idrevloride in hypertonic saline was safe and associated with improved lung function over a 28-day period in people with primary ciliary dyskinesia compared with hypertonic saline alone. Larger, longer clinical studies are warranted to explore the potential benefits of idrevloride in combination with hypertonic saline in people with primary ciliary dyskinesia.

FUNDING: Parion Sciences, under agreement with Vertex Pharmaceuticals.

PMID:37660715 | DOI:10.1016/S2213-2600(23)00226-6

Paediatr Respir Rev. 2023 Aug 24:S1526-0542(23)00048-9. doi: 10.1016/j.prrv.2023.08.004. Online ahead of print.

ABSTRACT

Newborn screening (NBS) for cystic fibrosis (CF) has enabled earlier diagnosis and has improved nutritional and growth-related outcomes in children with CF. For those with a positive NBS for CF that do not meet the diagnostic criteria for CF, the clinical entity called CFTR-Related Metabolic Syndrome (CRMS) or CF Screen- Positive, Inconclusive Diagnosis (CFSPID) is used. Although most children with CRMS remain relatively asymptomatic, studies have shown that between 11% and 48% of these patients may eventually progress to a diagnosis of CF over time. Although the CF Foundation guidelines for CRMS management and European CF Society guidelines for CFSPID have some similarities, there are also some differences. Here, we review challenging case scenarios that highlight remaining gaps in CRMS guidelines, thus supporting the need to update and unify existing guidelines.

PMID:37659865 | DOI:10.1016/j.prrv.2023.08.004

Bone. 2023 Aug 31:116890. doi: 10.1016/j.bone.2023.116890. Online ahead of print.

NO ABSTRACT

PMID:37659440 | DOI:10.1016/j.bone.2023.116890

Pediatrics. 2023 Sep 1;152(Suppl 2):e2023062292E. doi: 10.1542/peds.2023-062292E.

ABSTRACT

Lifelong respiratory health is rooted in the structural and functional development of the respiratory system in early life. Exposures and interventions antenatally through childhood can influence lung development into young adulthood, the life stage with the highest achievable lung function. Because early respiratory health sets the stage for adult lung function trajectories and risk of developing chronic obstructive pulmonary disease, understanding how to promote lung health in children will have far reaching personal and population benefits. To achieve this, it is critical to have accurate and precise measures of structural and functional lung development that track throughout life stages. From this foundation, evaluation of environmental, genetic, metabolic, and immune mechanisms involved in healthy lung development can be investigated. These goals require the involvement of general pediatricians, pediatric subspecialists, patients, and researchers to design and implement studies that are broadly generalizable and applicable to otherwise healthy and chronic disease populations. This National Institutes of Health workshop report details the key gaps and opportunities regarding lung function and structure.

PMID:37656029 | PMC:PMC10484309 | DOI:10.1542/peds.2023-062292E

BMC Pulm Med. 2023 Sep 1;23(1):323. doi: 10.1186/s12890-023-02611-4.

ABSTRACT

BACKGROUND: Cystic fibrosis (CF) is a life-limiting disorder that is characterised by respiratory tract inflammation that is mediated by a range of microbial pathogens. Small colony variants (SCVs) of common respiratory pathogens are being increasingly recognised in CF. The aim of this systematic review is to investigate the prevalence of SCVs, clinical characteristics and health outcomes for patients with CF, and laboratory diagnostic features of SCVs compared to non-small colony variants (NCVs) for a range of Gram-positive and Gram-negative respiratory pathogens.

METHODS: A literature search was conducted (PubMed, Web of Science, Embase and Scopus) in April 2020 to identify articles of interest. Data pertaining to demographic characteristics of participants, diagnostic criteria of SCVs, SCV prevalence and impact on lung function were extracted from included studies for analysis.

RESULTS: Twenty-five of 673 studies were included in the systematic review. Individuals infected with SCVs of Staphylococcus aureus (S. aureus) were more likely to have had prior use of the broad-spectrum antibiotic trimethoprim sulfamethoxazole (p < 0.001), and the prevalence of SCVs in patients infected with S. aureus was estimated to be 19.3% (95% CI: 13.5% to 25.9%). Additionally, patients infected with SCVs of Gram-negative and Gram-positive pathogens were identified to have a lower forced expiratory volume in one second percentage predicted (-16.8, 95% CI: -23.2 to -10.4) than those infected by NCVs. Gram-positive SCVs were commonly described as small and non-haemolytic, grown on Mannitol salt or blood agar for 24 h at 35°C and confirmed using tube coagulase testing.

CONCLUSION: The findings of this systematic review demonstrate that SCVs of S. aureus have a high prevalence in the CF community, and that the occurrence of SCVs in Gram-positive and Gram-negative pathogens is linked to poorer respiratory function. Further investigation is necessary to determine the effect of infection by SCVs on the CF population.

PMID:37658311 | DOI:10.1186/s12890-023-02611-4

An Pediatr (Engl Ed). 2023 Aug 30:S2341-2879(23)00189-8. doi: 10.1016/j.anpede.2023.08.007. Online ahead of print.

ABSTRACT

INTRODUCTION: The impact of skin diseases on quality of life varies widely, and some can have an impact similar to that of asthma or cystic fibrosis.

MATERIAL AND METHODS: We conducted a cross-sectional, observational and descriptive study with the aim of describing the degree to which quality of life was affected in paediatric patients managed in a dermatology clinic by means of the Children's Dermatology Life Quality Index (CDLQI).

RESULTS: In our study, the skin disease with the greatest impact on quality of life was atopic dermatitis, chiefly on account of symptoms like pruritus and insomnia. It was followed by acne, mainly due to the associated negative feelings (shame, sadness, etc.). Quality of life in patients with viral warts and molluscum contagiosum was mostly affected by the treatment, chiefly based on cryotherapy. Most patients with nevi or café-au-lait spots did not have a decreased quality of life, although up to one third of them had negative feelings in relation to their skin disease.

DISCUSSION: Atopic dermatitis was the common skin disease that caused the greatest impairment in quality of life in our sample, although other diseases also had an impact on different dimensions of quality of life. We ought to underscore the recommendation to use less painful treatments than cryotherapy for viral warts and molluscum contagiosum, as the impairment in quality of life in paediatric patients with these conditions was mainly due to the treatment.

PMID:37658021 | DOI:10.1016/j.anpede.2023.08.007

Biomed Pharmacother. 2023 Aug 30;166:115399. doi: 10.1016/j.biopha.2023.115399. Online ahead of print.

ABSTRACT

Over-production of reactive oxygen species (ROS) in the inner ear can be triggered by a variety of pathological events identified in animal models after traumatic noise exposure. Our previous research found that inhibition of the AMP-activated protein kinase alpha subunit (AMPKα) protects against noise-induced cochlear hair cell loss and hearing loss by reducing ROS accumulation. However, the molecular pathway through which AMPKα exerts its antioxidative effect is still unclear. In this study, we have investigated a potential target of AMPKα and ROS, cystic fibrosis transmembrane conductance regulator (CFTR), and the protective effect against noise-induced hair cell loss of an FDA-approved CFTR potentiator, ivacaftor, in FVB/NJ mice, mouse explant cultures, and HEI-OC1 cells. We found that noise exposure increases phosphorylation of CFTR at serine 737 (p-CFTR, S737), which reduces wildtype CFTR function, resulting in oxidative stress in cochlear sensory hair cells. Pretreatment with a single dose of ivacaftor maintains CFTR function by preventing noise-increased p-CFTR (S737). Furthermore, ivacaftor treatment increases nuclear factor E2-related factor 2 (Nrf2) expression, diminishes ROS formation, and attenuates noise-induced hair cell loss and hearing loss. Additionally, inhibition of noise-induced AMPKα activation by compound C also diminishes p-CFTR (S737) expression. In line with these in-vivo results, administration of hydrogen peroxide to cochlear explants or HEI-OC1 cells increases p-CFTR (S737) expression and induces sensory hair cell or HEI-OC1 cell damage, while application of ivacaftor halts these effects. Although ivacaftor increases Nrf2 expression and reduces ROS accumulation, cotreatment with ML385, an Nrf2 inhibitor, abolishes the protective effects of ivacaftor against hydrogen-peroxide-induced HEI-OC1 cell death. Our results indicate that noise-induced sensory hair cell damage is associated with p-CFTR. Ivacaftor has potential for treatment of noise-induced hearing loss by maintaining CFTR function and increasing Nrf2 expression for support of redox homeostasis in sensory hair cells.

PMID:37657258 | DOI:10.1016/j.biopha.2023.115399

J Community Genet. 2023 Sep 1. doi: 10.1007/s12687-023-00666-8. Online ahead of print.

ABSTRACT

The South Carolina cystic fibrosis (CF) newborn screening (NBS) program changed in 2019 to include CFTR genotyping for babies with top 4% immunoreactive trypsinogen, which improves sensitivity and timeliness but increases carrier detection. Carrier identification has genetic implications for the family and parents of NBS+ babies have increased emotional distress. Genetic counseling (GC) may increase parent understanding and reduce anxiety yet is not uniformly offered at CF centers. We report our early results after implementing GC for NBS+ families at the time of sweat chloride testing based on GC availability, which resulted in an unselected GC- control arm. Sixteen mothers (GC+ = 9, GC- = 7) participated in an online survey about their experience. Responses were analyzed in aggregate and for differences between GC+ and GC- groups. All-respondent sadness and anxiety increased with notification of the NBS+ result and decreased after sweat test results. Anxiety and sadness were greater in GC- compared to GC+ until after the diagnosis was resolved, though emotional differences between the groups were not statistically significant. On a scale of 0 = not at all to 10 = extremely, GC was rated very helpful (mean 9.0, range 5-10), informative (mean 8.9, range 4-10), comforting (mean 9.1, range 6-10), and minimally distracting (mean 1.8, range 0-9). All participants correctly identified that a risk for a child to have CF exists when both parents are (at least) carriers. Delivery of NBS results to respondents varied by timing, informant, and information given. The child's pediatrician notified 10 (62.5%) of the NBS+ result. Parents felt they were notified in a timely manner (68.8%), by someone knowledgeable about NBS (62.5%), the sweat test (62.5%), CF (43.8%), and genetics (43.8%) and who cared about them (81.3%). Parents felt worried (81.3%), confused (81.3%), empowered (25%), and other (sad, shocked, scared, overwhelmed, devastated, defeated). Data from this single-center study suggest benefit of GC, that families would value earlier contact with an expert, and that prompt diagnostic resolution may reduce duration of parental distress.

PMID:37656403 | DOI:10.1007/s12687-023-00666-8

Curr Opin Pulm Med. 2023 Sep 4. doi: 10.1097/MCP.0000000000001014. Online ahead of print.

ABSTRACT

PURPOSE OF REVIEW: This review highlights the problem of neuropsychiatric adverse effects (AEs) associated with elexacaftor/tezacaftor/ivacaftor (ETI), current suboptimal mitigation approaches, a novel testable mechanistic hypothesis, and potential solutions requiring further research.

RECENT FINDINGS: Studies show that a minority of persons with cystic fibrosis (PwCF) initiating cystic fibrosis transmembrane conductance regulator (CFTR) modulators experience neuropsychiatric AEs including worsening mood, cognition, anxiety, sleep, and suicidality. The GABA-A receptor is a ligand-gated chloride channel, and magnetic resonance spectroscopy neuroimaging studies have shown that reduced GABA expression in rostral anterior cingulate cortex is associated with anxiety and depression. Recent research details the impact of peripheral inflammation and the gut-brain axis on central neuroinflammation. Plasma ETI concentrations and sweat chloride have been evaluated in small studies of neuropsychiatric AEs but not validated to guide dose titration or correlated with pharmacogenomic variants or safety/efficacy.

SUMMARY: Although ETI is well tolerated by most PwCF, some experience debilitating neuropsychiatric AEs. In some cases, these AEs may be driven by modulation of CFTR and chloride transport within the brain. Understanding biological mechanisms is a critical next step in identifying which PwCF are likely to experience AEs, and in developing evidence-based strategies to mitigate them, while retaining modulator efficacy.

PMID:37655981 | DOI:10.1097/MCP.0000000000001014

Ann Am Thorac Soc. 2023 Sep;20(9):1235-1236. doi: 10.1513/AnnalsATS.202305-459ED.

NO ABSTRACT

PMID:37655958 | DOI:10.1513/AnnalsATS.202305-459ED

Digit Health. 2023 Aug 28;9:20552076231197023. doi: 10.1177/20552076231197023. eCollection 2023 Jan-Dec.

ABSTRACT

BACKGROUND: Cystic fibrosis causes mucus to build up in the lungs, digestive tract, and other areas. It is the most common chronic lung disease in children and young adults. It requires daily medical care. Before the COVID-19 pandemic, telerehabilitation and telehealth were used, but it was after this that there was a boom in these types of assistance in order to continue caring for cystic fibrosis patients.

OBJECTIVE: The objective is to evaluate the effect of telemedicine programs in people with cystic fibrosis.

METHODS: For the search, the PubMed, Scopus, Web of Science, PEDro, Cochrane, and CINAHL databases were used. Randomized controlled trials, pilot studies, and clinical trials have been included. The exclusion criteria have considered that the population did not have another active disease or that telemedicine was not used as the main intervention. This study follows the PRISMA statement and has been registered in the PROSPERO database (CRD42021257647).

RESULTS: A total of 11 articles have been included in the systematic review. No improvements have been found in quality of life, forced expiratory volume, and forced vital capacity. Good results have been found in increasing physical activity and early detection of exacerbations. Adherence and satisfaction are very positive and promising.

CONCLUSIONS: Despite not obtaining significant improvements in some of the variables, it should be noted that the adherence and satisfaction of both patients and workers reinforce the use of this type of care. Future studies are recommended in which to continue investigating this topic.

PMID:37654722 | PMC:PMC10467216 | DOI:10.1177/20552076231197023

Eur Respir J. 2023 Aug 31:2300522. doi: 10.1183/13993003.00522-2023. Online ahead of print.

ABSTRACT

BACKGROUND: Cystic Fibrosis (CF) is commonly characterised by thick respiratory mucous. From diagnosis, people with CF are prescribed daily physiotherapy, including airway clearance treatments (ACTs). ACTs consume a large proportion of treatment time, yet the efficacy and effectiveness of ACTs are poorly understood. This study aimed to evaluate associations between quality and quantity of ACTs and lung function in children and young people with CF.

METHODS: Project Fizzyo, a longitudinal observational cohort study, used remote-monitoring electronic pressure sensors with 4 different commercial ACT devices to record real-time, breath-by-breath pressure data during usual ACTs undertaken at home over 16 months in 145 children. ACTs were categorised either as conformant or not with current ACT recommendations based on breath pressure and length measurements, or as missed treatments if not recorded. Daily, weekly and monthly associations between ACT category and lung function were investigated using linear mixed effects regression models adjusting for clinical confounders.

RESULTS: After exclusions, 45 224 ACTs (135 individuals) and 21 069 days without treatments (141 individuals) were analysed. Average age of participants was 10.2 years (sd=2.9). Conformant ACTs (21%) had significantly higher FEV1 (mean effect size 0.23, 95%CI [0.19, 0.27]) than non-conformant (79%) or missed treatments. There was no benefit from non-conformant or missed treatments, and no significant difference in FEV1 between them (mean effect size 0.02 (95%CI, [-0.01, 0.05]).

CONCLUSION: ACTs are beneficial when done as recommended, but most people use techniques that do not improve lung function. Work is needed to monitor and improve ACT quality and to increase the proportion of people doing effective airway clearance at home.

PMID:37652570 | DOI:10.1183/13993003.00522-2023

Curr Gastroenterol Rep. 2023 Sep 1. doi: 10.1007/s11894-023-00896-3. Online ahead of print.

ABSTRACT

PURPOSE OF REVIEW: Cystic fibrosis is an inherited, multisystem disease that affects the gastrointestinal system in numerous ways. This article reviews the nutritional, gastrointestinal, and hepatobiliary manifestations of cystic fibrosis with an emphasis on the effects of CFTR modulator therapy.

RECENT FINDINGS: The life expectancy of individuals with cystic fibrosis has increased substantially in recent years. CFTR modulator therapy improves pulmonary function and results in weight gain. An individualized approach to nutrition is encouraged. Pancreatic exocrine function may improve with intervention early in life. The use of non-invasive methods to screen for hepatobiliary involvement is recommended. Highly effective CFTR modulators lead to increased survival and improved quality of life for many individuals. Their effects on gastrointestinal symptoms and hepatobiliary disease are not fully understood. Patient-reported outcome measures and biomarkers are important clinical endpoints for studying the effects of modulators.

PMID:37653358 | DOI:10.1007/s11894-023-00896-3

J Cyst Fibros. 2023 Aug 30:S1569-1993(23)00878-0. doi: 10.1016/j.jcf.2023.08.008. Online ahead of print.

NO ABSTRACT

PMID:37652838 | DOI:10.1016/j.jcf.2023.08.008

Cell Rep. 2023 Aug 30;42(9):113056. doi: 10.1016/j.celrep.2023.113056. Online ahead of print.

ABSTRACT

Suppression of premature termination codons (PTCs) by translational readthrough is a promising strategy to treat a wide variety of severe genetic diseases caused by nonsense mutations. Here, we present two potent readthrough promoters-NVS1.1 and NVS2.1-that restore substantial levels of functional full-length CFTR and IDUA proteins in disease models for cystic fibrosis and Hurler syndrome, respectively. In contrast to other readthrough promoters that affect stop codon decoding, the NVS compounds stimulate PTC suppression by triggering rapid proteasomal degradation of the translation termination factor eRF1. Our results show that this occurs by trapping eRF1 in the terminating ribosome, causing ribosome stalls and subsequent ribosome collisions, and activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25.

PMID:37651229 | DOI:10.1016/j.celrep.2023.113056

Hum Gene Ther. 2023 Aug 31. doi: 10.1089/hum.2023.095. Online ahead of print.

ABSTRACT

Cystic fibrosis (CF) is potentially treatable by gene therapy. Since the identification of the CF gene, preclinical and clinical trials have concentrated on achieving effective gene therapy targeting the lung. However, the lung has proven to be a formidable barrier to successful gene therapy especially for CF1 and many clinical trials failed to achieve efficacy2. Recent advances in vector design and Adenoassociated (AAV) serotypes have increased the chances of success 3. Given that CF is a multiorgan disease 4, the goal of this study is to test whether a gene therapy approach involving AAV1 or 6 vector delivery via the systemic circulation would at the same time overcome the barrier of lung delivery and transduce organs commonly affected by CF. To accomplish this, we sprayed AAV1 containing green fluorescent protein (GFP) into the trachea or injected it intravenously. We also tested AAV6 injected intravenously. No adverse events were noted. Ferrets were necropsied 30 days after vector delivery. AAV1 or AAV6 vector genomes, mRNA expression, and GFP protein were detected in all the tracheal and lung samples from the treated animals, whether AAV1 was sprayed into the trachea or injected intravenously or AAV6 was injected intravenously. Importantly, both surface epithelial and basal cells of the trachea and lung airways were successfully transduced, regardless of which route of delivery or vector serotype used for transduction. We detected also AAV1 and AAV6 vector genomes, mRNA expression, and GFP protein in the livers and pancreata, particularly in the acinar cells of the pancreatic duct. These data suggest that gene transfer is attainable in the airways, liver, and pancreas using either serotype, AAV1 or AAV6. Given that these same organs are affected in CF, systemic delivery of AAV maybe the preferred route of delivery for a gene therapy for CF.

PMID:37650819 | DOI:10.1089/hum.2023.095

ERJ Open Res. 2023 Aug 29;9(4):00356-2023. doi: 10.1183/23120541.00356-2023. eCollection 2023 Jul.

ABSTRACT

AMS in chronic lung disease can be challenging. Causal treatment of treatable traits may be the most successful AMS strategy for patients with any chronic pulmonary disease and should be brought into focus. https://bit.ly/3ptrmV8.

PMID:37650087 | PMC:PMC10463032 | DOI:10.1183/23120541.00356-2023

Hum Mol Genet. 2023 Aug 31:ddad143. doi: 10.1093/hmg/ddad143. Online ahead of print.

ABSTRACT

Small molecule drugs known as modulators can treat ~ 90% of people with cystic fibrosis (CF), but do not work for premature termination codon variants such as W1282X (c.3846G > A). Here we evaluated two gene editing strategies, Adenine Base Editing (ABE) to correct W1282X, and Homology-Independent Targeted Integration (HITI) of a CFTR superexon comprising exons 23-27 (SE23-27) to enable expression of a CFTR mRNA without W1282X. In Flp-In-293 cells stably expressing a CFTR expression minigene bearing W1282X, ABE corrected 24% of W1282X alleles, rescued CFTR mRNA from nonsense mediated decay and restored protein expression. However, bystander editing at the adjacent adenine (c.3847A > G), caused an amino acid change (R1283G) that affects CFTR maturation and ablates ion channel activity. In primary human nasal epithelial cells homozygous for W1282X, ABE corrected 27% of alleles, but with a notably lower level of bystander editing, and CFTR channel function was restored to 16% of wild-type levels. Using the HITI approach, correct integration of a SE23-27 in intron 22 of the CFTR locus in 16HBEge W1282X cells was detected in 5.8% of alleles, resulting in 7.8% of CFTR transcripts containing the SE23-27 sequence. Analysis of a clonal line homozygous for the HITI-SE23-27 produced full-length mature protein and restored CFTR anion channel activity to 10% of wild-type levels, which could be increased three-fold upon treatment with the triple combination of CF modulators. Overall, these data demonstrate two different editing strategies can successfully correct W1282X, the second most common class I variant, with a concomitant restoration of CFTR function.

PMID:37649273 | DOI:10.1093/hmg/ddad143