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A major unmet need in the cystic fibrosis (CF) therapeutic landscape is the lack of effective treatments for nonsense CFTR mutations, which affect approximately 10% of CF patients. Correction of nonsense CFTR mutations via genomic editing represents a promising therapeutic approach. In this study, we tested whether prime editing, a novel CRISPR-based genomic editing method, can be a potential therapeutic modality to correct nonsense CFTR mutations. We generated iPSCs from a CF patient homozygous for the CFTR W1282X mutation. We demonstrated that prime editing corrected one mutant allele in iPSCs, which effectively restored CFTR function in iPSC-derived airway epithelial cells and organoids. We further demonstrated that prime editing may directly repair mutations in iPSC-derived airway epithelial cells when the prime editing machinery is efficiently delivered by helper-dependent adenovirus (HDAd). Together, our data demonstrated that prime editing may potentially be applied to correct CFTR mutations such as W1282X., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: S.M.R. provided consulting services and received grants from Novartis, TranslateBio, Galapagos/Abbvie, Synedgen/Synspira, Eloxx, Vertex Pharmaceuticals, Ionis, Astra Zenica, Renovion, Cystetic Medicines, and Arcturus. S.M.R. is the inventor or co-inventor of several patents and held stock or stock options of Synedgen/Synspira and Renovion. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2023 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: We previously discovered that Korean red ginseng aqueous extract (RGAE) potentiates the TMEM16A channel, improved mucociliary transport (MCT) parameters in CF nasal epithelia in vitro, and thus could serve as a therapeutic strategy to rescue the MCT defect in cystic fibrosis (CF) airways. The hypothesis of this study is that RGAE can improve epithelial Cl - secretion, MCT, and histopathology in an in-vivo CF rat model., Methods: Seventeen 4-month old CFTR -/- rats were randomly assigned to receive daily oral control (saline, n = 9) or RGAE (Ginsenosides 0.4mg/kg/daily, n = 8) for 4 weeks. Outcomes included nasal Cl - secretion measured with the nasal potential difference (NPD), functional microanatomy of the trachea using micro-optical coherence tomography, histopathology, and immunohistochemical staining for TMEM16a., Results: RGAE-treated CF rats had greater mean NPD polarization with UTP (control = -5.48 +/- 2.87 mV, RGAE = -9.49 +/- 2.99 mV, p < 0.05), indicating, at least in part, potentiation of UTP-mediated Cl - secretion through TMEM16A. All measured tracheal MCT parameters (airway surface liquid, periciliary liquid, ciliary beat frequency, MCT) were significantly increased in RGAE-treated CF rats with MCT exhibiting a 3-fold increase (control, 0.45+/-0.31 vs. RGAE, 1.45+/-0.66 mm/min, p < 0.01). Maxillary mucosa histopathology was markedly improved in RGAE-treated cohort (reduced intracellular mucus, goblet cells with no distention, and shorter epithelial height). TMEM16A expression was similar between groups., Conclusion: RGAE improves TMEM16A-mediated transepithelial Cl - secretion, functional microanatomy, and histopathology in CF rats. Therapeutic strategies utilizing TMEM16A potentiators to treat CF airway disease are appropriate and provide a new avenue for mutation-independent therapies., Competing Interests: Declaration of Competing Interest Bradford A. Woodworth, M.D. is a consultant for Cook Medical, Smith and Nephew, and Medtronic. All other authors have no conflicts of interest to report., (Copyright © 2023. Published by Elsevier B.V.)

Background: Mucus stasis, a hallmark of muco-obstructive disease, results from impaired mucociliary transport and leads to lung function decline and chronic infection. Although therapeutics that target mucus stasis in the airway, such as hypertonic saline or rhDNAse, show some therapeutic benefit, they do not address the underlying electrostatic defect apparent in mucins in CF and related conditions. We have previously shown poly (acetyl, arginyl) glucosamine (PAAG, developed as SNSP113), a soluble, cationic polymer, significantly improves mucociliary transport in a rat model of CF by normalizing the charge defects of CF mucin. Here, we report efficacy in the CFTR-sufficient, ENaC hyperactive, Scnn1b-Tg mouse model that develops airway muco-obstruction due to sodium hyperabsorption and airway dehydration., Methods: Scnn1b-Tg mice were treated with either 250 µg/mL SNSP113 or vehicle control (1.38% glycerol in PBS) via nebulization once daily for 7 days and then euthanized for analysis. Micro-Optical Coherence Tomography-based evaluation of excised mouse trachea was used to determine the effect on the functional microanatomy. Tissue analysis was performed by routine histopathology., Results: Nebulized treatment of SNSP113 significantly improved mucociliary transport in the airways of Scnn1b-Tg mice, without altering the airway surface or periciliary liquid layer. In addition, SNSP113 significantly reversed epithelial hypertrophy and goblet cell metaplasia. Finally, SNSP113 significantly ameliorated eosinophilic crystalline pneumonia and lung consolidation in addition to inflammatory macrophage influx in this model., Conclusion: Overall, this study extends the efficacy of SNSP113 as a potential therapeutic to alleviate mucus stasis in muco-obstructive diseases in CF and potentially in related conditions., Competing Interests: Declaration of Competing Interest Steven M. Rowe received grant funding and consulting fees from Synspira and Synedgen that ended in 2022. Shenda M. Baker provided SNSP113 (PAAG) used in study. Elex S. Harris, Lea Novak, Courtney M. Fernandez-Petty, and Susan E. Birket have no conflicts of interest to report., (Copyright © 2023. Published by Elsevier B.V.)

Cystic fibrosis (CF) is a genetic disease hallmarked by aberrant ion transport that results in delayed mucus clearance, chronic infection, and progressive lung function decline. Several animal models have been developed to study the airway anatomy and mucus physiology in CF, but they are costly and difficult to maintain, making them less accessible for many applications. A more available CFTR-/- rat model has been developed and characterized to develop CF airway abnormalities, but consistent dosing of pharmacologic agents and longitudinal evaluation remain a challenge. In this study, we report the development and characterization of a novel ex vivo trachea model that utilizes both wild type (WT) and CFTR-/- rat tracheae cultured on a porcine gelatin matrix. Here we show that the ex vivo tracheae remain viable for weeks, maintain a CF disease phenotype that can be readily quantified, and respond to stimulation of mucus and fluid secretion by cholinergic stimulation. Furthermore, we show that ex vivo tracheae may be used for well-controlled pharmacological treatments, which are difficult to perform on freshly excised trachea or in vivo models with this degree of scrutiny. With improved interrogation possible with a durable trachea, we also established firm evidence of a gland secretion defect in CFTR-/- rat tracheae compared to WT controls. Finally, we demonstrate that the ex vivo tracheae can be used to generate high mucus protein yields for subsequent studies, which are currently limited by in vivo mucus collection techniques. Overall, this study suggests that the ex vivo trachea model is an effective, easy to set up culture model to study airway and mucus physiology., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Harris et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The growing use of modulator therapies aimed at restoring cystic fibrosis transmembrane conductance regulator (CFTR) protein function in people with cystic fibrosis has fundamentally altered clinical trial strategies needed to advance new therapeutics across an orphan disease population that is now divided by CFTR modulator eligibility. The development of a robust pipeline of nucleic acid-based therapies (NABTs)-initially directed towards the estimated 10% of the cystic fibrosis population who are genetically ineligible for, or intolerant of, CFTR modulators-is dependent on the optimisation of restricted trial participant resources across multiple development programmes, a challenge that will preclude the use of gold standard placebo-controlled trials. Advancement of a full pipeline of symptomatic therapies across the entire cystic fibrosis population will be challenged by smaller effect sizes and uncertainty regarding their clinical importance in a growing modulator-treated population with more mild and stable pulmonary disease. In this Series paper, we aim to lay the foundation for clinical trial strategy and community partnership that must deviate from established and familiar precedent to advance the future pipeline of cystic fibrosis therapeutics., Competing Interests: Declaration of interests NM-H reports grants from the Cystic Fibrosis Foundation (CFF), the National Institutes of Health (NIH; P30 DK 089507 and UL1 TR002319), and the Food and Drug Administration (FDA); consulting fees from Enterprise Therapeutics; and data safety monitoring board (DSMB) membership for the NIH. JPC is an employee of CFF. RJ reports grants from CFF; consulting fees from Boehringer Ingelheim and Recode Therapeutics; honoraria from Vertex Pharmaceuticals; and travel support from CFF. SHD reports contracts from Calithera, CFF, NIH (P30 DK065988), Vertex Pharmaceuticals, 4D Molecular Therapeutics, and Chiesi USA; consulting fees from Polarean, 501 Ventures, Enterprise Therapeutics, and Boehringer Ingelheim; fees for participation on advisory boards for Innova Healthcare and Boehringer Ingleheim; travel fees from Enterprise Therapeutics and CFF; and participation on a board for Abbvie. IF reports grants from AbbVie, Bayer, Boehringer Ingelheim, Insmed, GSK, and Vertex Pharmaceuticals; honoraria from Vertex Pharmaceuticals; board participation for AbbVie, Boehringer Ingelheim, Kither Biotech, and Vertex Pharmaceuticals; and support to her institution from the European Cystic Fibrosis Society (ECFS). CHG reports grants and contracts from CFF, NIH (P30 DK 089507 and UL1 TR000423), and FDA; consulting fees from Enterprise Therapeutics; honoraria from Gilead Sciences and Vertex Pharmaceuticals; travel support from Vertex Pharmaceuticals and Enterprise Therapeutics; participation on the board for Novartis; stock options for Air Therapeutics; and leadership roles for the American Thoracic Society (ATS). DP reports grants from CFF (002805121), NIH, and Aclaris Pharmaceuticals; travel support from CFF; and board participation for Vertex Pharmaceuticals and Translate Bio. FR reports grants from Vertex Pharmaceuticals and consulting fees from Vertex Pharmaceuticals and Calithera. BSQ reports grants from CFF, Cystic Fibrosis Canada, Vertex Pharmaceuticals, and Gilead Sciences; honoraria from Vertex Pharmaceuticals; and travel support from CFF. ETZ reports grants from NIH, Vertex Pharmaceuticals, and CFF (002884121); consulting fees from CFF; travel support from CFF, Vertex Pharmaceuticals, and ECFS; and participation on boards for CFF and Vertex Pharmaceuticals. SCB reports grants from the National Health and Medical Research Council Australia (APP1102494), the Medical Research Futures Fund Australia, and CFF (BELL1480 and BELL19A0); and honoraria from Vertex Pharmaceuticals. JCD reports grants from the UK Cystic Fibrosis Trust (as part of their Clinical Trials Accelerator Platform), CFF, Cystic Fibrosis Ireland, the Engineering and Physical Sciences Research Council, and the National Institute for Health and Care Research; and honoraria from Vertex Pharmaceuticals, Boehringer Ingelheim, Eloxx, Algipharma, Abbvie, Arcturus, Enterprise Therapeutics, Recode, LifeArc, Genentech, and Tavanta. JCD serves as Deputy Editor for the Journal of Cystic Fibrosis. MWK reports grants from NIH (P01HL128192 and UL1TR002548) and CFF; consulting fees from AbbVie, AzurRx, Cystetic Medicines, EnBiotix, First Wave Biopharma, Insmed, Laurent Pharmaceuticals, Mylan, and PBM BC Holdings; board participation for AbbVie, CFF, First Wave Biopharma, Insmed, Laurent Pharmaceuticals, Sionna, and Vertex; and committee membership for CFF. MAM reports grants from the German Research Foundation (CRC 1449 project #431232613), the German Ministry for Education and Research (82DZL009B1), the German Innovation Fund, and Vertex Pharmaceuticals; consulting fees from Abbvie, Antabio, Arrowhead, Boehringer Ingelheim, Enterprise Therapeutics, Kither Biotec, Prieris, Recode, Santhera, Splisense, and Vertex Pharmaceuticals; honoraria from Vertex Pharmaceuticals; travel support from Boehringer Ingelheim and Vertex Pharmaceuticals; and participation on boards for Abbvie, Antabio, Arrowhead, Boehringer Ingelheim, Enterprise Therapeutics, Kither Biotec, Pari, and Vertex Pharmaceuticals. EM reports grants from Vertex Pharmaceuticals; honoraria from Vertex Phamaceuticals; travel support from Menarini; and board participation for the Cystic Fibrosis Storm Clinical Trial, Vertex Pharmaceuticals, Janssen, Abbvie, and Insmed. JHR reports grants from Cystic Fibrosis Canada, CFF, Vertex Phamaceuticals, the Canada Foundation for Innovation, and the Canadian Institutes of Health Research; consulting fees from Sanofi; and travel support from Vertex Pharmaceuticals. SMR reports grant funding from CFF (P30DK072482), NIH (UL1TR003096), Vertex Pharmaceuticals, Galapagos/Abbvie, Eloxx, Synspira, Translate Bio, Arcturus, Astra-Zenica, and Ionis; and consulting fees from Vertex Pharmaceuticals, Synspira (including stock options), Renovion (including stock options), Cystetic Medicines, and Arcturus. SMR's potential competing interests were resolved or ended in 2022 or earlier. JLT-C reports grants and contracts from CFF, Vertex Pharmaceutics, Eloxx, and 4DMT; consulting fees from Vertex Phamaceuticals, Insmed, and 4DMT; participation on a DSMB for Abbvie; and participation on advisory boards for CFF, ATS, Journal of Cystic Fibrosis, The Lancet Respiratory Medicine, and Emily's Entourage. GR-B reports grants and contracts from Vertex Pharmaceuticals and CFF. DGD reports grants from Chiesi Farmaceutici and CFF; consulting fees from Vertex and Insmed; honoraria from Chiesi and Gilead; travel support from ECFS and CFF; board participation for Momab and CSL Behring; and support from ECFS as director of the Clinical Trials Network. MJ, NRK, TL, KP, JMP, and LQ declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Speciation leads to adaptive changes in organ cellular physiology and creates challenges for studying rare cell-type functions that diverge between humans and mice. Rare cystic fibrosis transmembrane conductance regulator (CFTR)-rich pulmonary ionocytes exist throughout the cartilaginous airways of humans 1,2 , but limited presence and divergent biology in the proximal trachea of mice has prevented the use of traditional transgenic models to elucidate ionocyte functions in the airway. Here we describe the creation and use of conditional genetic ferret models to dissect pulmonary ionocyte biology and function by enabling ionocyte lineage tracing (FOXI1-Cre ERT2 ::ROSA-TG), ionocyte ablation (FOXI1-KO) and ionocyte-specific deletion of CFTR (FOXI1-Cre ERT2 ::CFTR L/L ). By comparing these models with cystic fibrosis ferrets 3,4 , we demonstrate that ionocytes control airway surface liquid absorption, secretion, pH and mucus viscosity-leading to reduced airway surface liquid volume and impaired mucociliary clearance in cystic fibrosis, FOXI1-KO and FOXI1-Cre ERT2 ::CFTR L/L ferrets. These processes are regulated by CFTR-dependent ionocyte transport of Cl - and HCO 3 - . Single-cell transcriptomics and in vivo lineage tracing revealed three subtypes of pulmonary ionocytes and a FOXI1-lineage common rare cell progenitor for ionocytes, tuft cells and neuroendocrine cells during airway development. Thus, rare pulmonary ionocytes perform critical CFTR-dependent functions in the proximal airway that are hallmark features of cystic fibrosis airway disease. These studies provide a road map for using conditional genetics in the first non-rodent mammal to address gene function, cell biology and disease processes that have greater evolutionary conservation between humans and ferrets., (© 2023. The Author(s).)

Cyclopropanes are highly useful motifs that are often incorporated into drug candidates to improve potency, metabolic stability, or pharmacokinetic properties. An expedient method for the α-cyclopropanation of ketones using hydrogen borrowing (HB) catalysis is described. The transformation occurs via HB alkylation of a hindered ketone with subsequent intramolecular displacement of a pendant leaving group affording the cyclopropanated product. The leaving group can be installed in either the ketone or alcohol component of the HB system, giving access to α-cyclopropyl ketones via two complementary approaches. Conversion to the corresponding carboxylic acids can be achieved in a simple two-step sequence to afford synthetically useful 1,1-substituted spirocyclopropyl acid building blocks.

Background: MRT5005, a codon-optimized CFTR mRNA, delivered by aerosol in lipid nanoparticles, was designed as a genotype-agnostic treatment for CF lung disease., Methods: This was a randomized, double-blind, placebo-controlled Phase 1/2 study performed in the US. Adults with 2 severe class I and/or II CFTR mutations and baseline ppFEV1 values between 50 and 90% were randomized 3:1 (MRT5005: placebo). Six dose levels of MRT5005 (4, 8, 12, 16, 20, and 24 mg) or placebo (0.9% Sodium Chloride) were administered by nebulization. The single ascending dose cohort was treated over a range from 8 to 24 mg; the multiple ascending dose cohort received five weekly doses (range 8-20 mg); and the daily dosing cohort received five daily doses (4 mg)., Results: A total of 42 subjects were assigned to MRT5005 [31] or placebo [11]. A total of 14 febrile reactions were observed in 10 MRT5005-treated participants, which were mild [3] or moderate [11] in severity; two subjects discontinued related to these events. Additionally, two MRT5005-treated patients experienced hypersensitivity reactions, which were managed conservatively. The most common treatment emergent adverse events were cough and headache. No consistent effects on FEV1 were noted., Conclusions: MRT5005 was generally safe and well tolerated through 28 days of follow-up after the last dose, though febrile and hypersensitivity reactions were noted. The majority of these reactions resolved within 1-2 days with supportive care allowing continued treatment with MRT5005 and careful monitoring. In this small first-in-human study, FEV1 remained stable after treatment, but no beneficial effects on FEV1 were observed., Competing Interests: Declaration of Competing Interest The authors have completed ICMJE disclosure of interest forms. MJ, JL, KDM, and SZN report no competing interests. JBZ, CB, JCC, DD, NL, SL, SMR, KAM, KSM, and MSS report clinical trial funding from Translate Bio to their institution for this study. MSS, EBM, KAM, and JCC report support for the current manuscript from Emily's Entourage. DD reports research contracts with Insmed, Inc., Aridis Pharmaceuticals, Armata Pharmaceuticals, and 4D Molecular Therapeutics and fees from the CFF for his role on the Data Safety Monitoring Board (DSMB). DD is a member of the DSMB at the University of Pennsylvania. KSM reports research grants to her institution from the CFF in partnership with 4D Molecular Therapeutics, Abbvie, Aridis Pharmaceuticals, Armata Pharmaceuticals, Boeringer-Ingelheim, Corbus, Insmed, Laurent Pharmaceuticals, Novartis, Eloxx, Vertex Pharmaceuticals, Savara, and Proteostasis for unrelated research. SMR reports research grants to his institution from the CFF in partnership with Novartis, Galapagos/Abbvie, Synedgen/Synspira, Eloxx, Vertex Pharmaceuticals, Ionis, and Astra Zenica for unrelated research. SMR reports consulting fees for clinical trial design and conduct from Novartis, Galapagos/Abbvie, Synedgen/Synspira, Vertex Pharmaceuticals, Renovion, Ionis, Cystetic Medicines, and Arcturus. JBZ reports fees from the CFF for his role on the DSMB and research grants from the CFF in partnership with Laurent Pharmaceuticals, Savara, AzureRx Biopharma, Aridis Pharmaceuticals, and Vertex Pharmaceuticals for unrelated research but no personal payments. AB, EBM and MV were full-time employees of Translate Bio during the conduct of the study. MV was an employee of Rho, Inc. and is currently an employee of Krystal Biotech. MV reports stock options provided to employees of Translate Bio and Krystal Biotech. MV is former board member of the CFF Central Carolinas Chapter. AB is currently on the Board of Directors for Pieris Pharmaceuticals. CB reports research grants from the CFF and CFF Therapeutic Development Network (CFFTDN) in partnership with Vertex pharmaceuticals for unrelated research but no personal payments. MSS reports research grants to his institution from the CFF in partnership with Vertex Pharmaceuticals and consulting fees from Vertex Pharmaceuticals. MVI reports research grants from the CFF and CFFTDN. To advance drug development and a search for a cure, the CFF has contracts with several companies to help fund the development of potential treatments and/or cures for CF. Pursuant to these contracts, CFF may receive milestone-based payments, equity interests, royalties on the net sales of therapies, and/or other forms of consideration. Resulting revenue received by CFF is used in support of their mission., (Copyright © 2023 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Nonsense mutations are the underlying cause of approximately 11% of all inherited genetic diseases 1 . Nonsense mutations convert a sense codon that is decoded by tRNA into a premature termination codon (PTC), resulting in an abrupt termination of translation. One strategy to suppress nonsense mutations is to use natural tRNAs with altered anticodons to base-pair to the newly emerged PTC and promote translation 2-7 . However, tRNA-based gene therapy has not yielded an optimal combination of clinical efficacy and safety and there is presently no treatment for individuals with nonsense mutations. Here we introduce a strategy based on altering native tRNAs into  efficient suppressor tRNAs (sup-tRNAs) by individually fine-tuning their sequence to the physico-chemical properties of the amino acid that they carry. Intravenous and intratracheal lipid nanoparticle (LNP) administration of sup-tRNA in mice restored the production of functional proteins with nonsense mutations. LNP-sup-tRNA formulations caused no discernible readthrough at endogenous native stop codons, as determined by ribosome profiling. At clinically important PTCs in the cystic fibrosis transmembrane conductance regulator gene (CFTR), the sup-tRNAs re-established expression and function in cell systems and patient-derived nasal epithelia and restored airway volume homeostasis. These results provide a framework for the development of tRNA-based therapies with a high molecular safety profile and high efficacy in targeted PTC suppression., (© 2023. The Author(s).)

Ten percent of cystic fibrosis (CF) patients carry a premature termination codon (PTC); no mutation-specific therapies exist for these individuals. ELX-02, a synthetic aminoglycoside, suppresses translation termination at PTCs (i.e., readthrough) by promoting the insertion of an amino acid at the PTC and restoring expression of full-length CFTR protein. The identity of amino acids inserted at PTCs affects the processing and function of the resulting full-length CFTR protein. We examined readthrough of the rare G550X-CFTR nonsense mutation due to its unique properties. We found that forskolin-induced swelling in G550X patient-derived intestinal organoids (PDOs) was significantly higher than in G542X PDOs (both UGA PTCs) with ELX-02 treatment, indicating greater CFTR function from the G550X allele. Using mass spectrometry, we identified tryptophan as the sole amino acid inserted in the G550X position during ELX-02- or G418-mediated readthrough, which differs from the three amino acids (cysteine, arginine, and tryptophan) inserted in the G542X position after treatment with G418. Compared with wild-type CFTR, Fischer rat thyroid (FRT) cells expressing the G550W-CFTR variant protein exhibited significantly increased forskolin-activated Cl - conductance, and G550W-CFTR channels showed increased PKA sensitivity and open probability. After treatment with ELX-02 and CFTR correctors, CFTR function rescued from the G550X allele in FRTs reached 20-40% of the wild-type level. These results suggest that readthrough of G550X produces greater CFTR function because of gain-of-function properties of the CFTR readthrough product that stem from its location in the signature LSGGQ motif found in ATP-binding cassette (ABC) transporters. G550X may be a particularly sensitive target for translational readthrough therapy. NEW & NOTEWORTHY We found that forskolin-induced swelling in G550X-CFTR patient-derived intestinal organoids (PDOs) was significantly higher than in G542X-CFTR PDOs after treatment with ELX-02. Tryptophan (W) was the sole amino acid inserted in the G550X position after readthrough. Resulting G550W-CFTR protein exhibited supernormal CFTR activity, PKA sensitivity, and open probability. These results show that aminoglycoside-induced readthrough of G550X produces greater CFTR function because of the gain-of-function properties of the CFTR readthrough product.

Adeno-associated virus (AAV) vector has shown multiple clinical breakthroughs, but its clinical implementation in inhaled gene therapy remains elusive due to difficulty in transducing lung airway cells. We demonstrate here AAV serotype 6 (AAV6) associated with extracellular vesicles (EVs) and secreted from vector-producing HEK-293 cells during vector preparation (EVAAV6) as a safe and highly efficacious gene delivery platform for inhaled gene therapy applications. Specifically, we discovered that EVAAV6 provided markedly enhanced reporter transgene expression in mucus-covered air-liquid interface (ALI) cultures of primary human bronchial and nasal epithelial cells as well as in mouse lung airways compared to standard preparations of AAV6 alone. Of note, AAV6 has been previously shown to outperform other clinically tested AAV serotypes, including those approved by the FDA for treating non-lung diseases, in transducing ALI cultures of primary human airway cells. We provide compelling experimental evidence that the superior performance of EVAAV6 is attributed to the ability of EV to facilitate mucus penetration and cellular entry/transduction of AAV6. The tight and stable linkage between AAV6 and EVs appears essential to exploit the benefits of EVs given that a physical mixture of individually prepared EVs and AAV6 failed to mediate EV-AAV6 interactions or to enhance gene transfer efficacy., (© 2023 The Authors. Journal of Extracellular Vesicles published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles.)

Background: Elexacaftor-tezacaftor-ivacaftor has been shown to be safe and efficacious in people with cystic fibrosis and at least one F508del allele. Our aim was to identify a novel cystic fibrosis transmembrane conductance regulator (CFTR) modulator combination capable of further increasing CFTR-mediated chloride transport, with the potential for once-daily dosing., Methods: We conducted two phase 2 clinical trials to assess the safety and efficacy of a once-daily combination of vanzacaftor-tezacaftor-deutivacaftor in participants with cystic fibrosis who were aged 18 years or older. A phase 2 randomised, double-blind, active-controlled study (VX18-561-101; April 17, 2019, to Aug 20, 2020) was carried out to compare deutivacaftor monotherapy with ivacaftor monotherapy in participants with CFTR gating mutations, following a 4-week ivacaftor monotherapy run-in period. Participants were randomly assigned to receive either ivacaftor 150 mg every 12 h, deutivacaftor 25 mg once daily, deutivacaftor 50 mg once daily, deutivacaftor 150 mg once daily, or deutivacaftor 250 mg once daily in a 1:1:2:2:2 ratio. The primary endpoint was absolute change in ppFEV 1 from baseline at week 12. A phase 2 randomised, double-blind, controlled, proof-of-concept study of vanzacaftor-tezacaftor-deutivacaftor (VX18-121-101; April 30, 2019, to Dec 10, 2019) was conducted in participants with cystic fibrosis and heterozygous for F508del and a minimal function mutation (F/MF genotypes) or homozygous for F508del (F/F genotype). Participants with F/MF genotypes were randomly assigned 1:2:2:1 to receive either 5 mg, 10 mg, or 20 mg of vanzacaftor in combination with tezacaftor-deutivacaftor or a triple placebo for 4 weeks, and participants with the F/F genotype were randomly assigned 2:1 to receive either vanzacaftor (20 mg)-tezacaftor-deutivacaftor or tezacaftor-ivacaftor active control for 4 weeks, following a 4-week tezacaftor-ivacaftor run-in period. Primary endpoints for part 1 and part 2 were safety and tolerability and absolute change in ppFEV 1 from baseline to day 29. Secondary efficacy endpoints were absolute change from baseline at day 29 in sweat chloride concentrations and Cystic Fibrosis Questionnaire-Revised (CFQ-R) respiratory domain score. These clinical trials are registered with ClinicalTrials.gov, NCT03911713 and NCT03912233, and are complete., Findings: In study VX18-561-101, participants treated with deutivacaftor 150 mg once daily (n=23) or deutivacaftor 250 mg once daily (n=24) had mean absolute changes in ppFEV 1 of 3·1 percentage points (95% CI -0·8 to 7·0) and 2·7 percentage points (-1·0 to 6·5) from baseline at week 12, respectively, versus -0·8 percentage points (-6·2 to 4·7) with ivacaftor 150 mg every 12 h (n=11); the deutivacaftor safety profile was consistent with the established safety profile of ivacaftor 150 mg every 12 h. In study VX18-121-101, participants with F/MF genotypes treated with vanzacaftor (5 mg)-tezacaftor-deutivacaftor (n=9), vanzacaftor (10 mg)-tezacaftor-deutivacaftor (n=19), vanzacaftor (20 mg)-tezacaftor-deutivacaftor (n=20), and placebo (n=10) had mean changes relative to baseline at day 29 in ppFEV 1 of 4·6 percentage points (-1·3 to 10·6), 14·2 percentage points (10·0 to 18·4), 9·8 percentage points (5·7 to 13·8), and 1·9 percentage points (-4·1 to 8·0), respectively, in sweat chloride concentration of -42·8 mmol/L (-51·7 to -34·0), -45·8 mmol/L (95% CI -51·9 to -39·7), -49·5 mmol/L (-55·9 to -43·1), and 2·3 mmol/L (-7·0 to 11·6), respectively, and in CFQ-R respiratory domain score of 17·6 points (3·5 to 31·6), 21·2 points (11·9 to 30·6), 29·8 points (21·0 to 38·7), and 3·3 points (-10·1 to 16·6), respectively. Participants with the F/F genotype treated with vanzacaftor (20 mg)-tezacaftor-deutivacaftor (n=18) and tezacaftor-ivacaftor (n=10) had mean changes relative to baseline (taking tezacaftor-ivacaftor) at day 29 in ppFEV 1 of 15·9 percentage points (11·3 to 20·6) and -0·1 percentage points (-6·4 to 6·1), respectively, in sweat chloride concentration of -45·5 mmol/L (-49·7 to -41·3) and -2·6 mmol/L (-8·2 to 3·1), respectively, and in CFQ-R respiratory domain score of 19·4 points (95% CI 10·5 to 28·3) and -5·0 points (-16·9 to 7·0), respectively. The most common adverse events overall were cough, increased sputum, and headache. One participant in the vanzacaftor-tezacaftor-deutivacaftor group had a serious adverse event of infective pulmonary exacerbation and another participant had a serious rash event that led to treatment discontinuation. For most participants, adverse events were mild or moderate in severity., Interpretation: Once-daily dosing with vanzacaftor-tezacaftor-deutivacaftor was safe and well tolerated and improved lung function, respiratory symptoms, and CFTR function. These results support the continued investigation of vanzacaftor-tezacaftor-deutivacaftor in phase 3 clinical trials compared with elexacaftor-tezacaftor-ivacaftor., Funding: Vertex Pharmaceuticals., Competing Interests: Declaration of interests AZU received grants from the Cystic Fibrosis Foundation and the CFF-Therapeutic Development Network for the present work; received payment or honoraria from Vertex Pharmaceuticals for presentations at CF Centers in UK; and participated in advisory boards for Vertex and Eloxx. VI received grant support from CF TDN for the present work; consulting fees from Mylan for CF—TOBI podhaler advisory board; and grant support from CFF for meeting attendance. PA received support from Vertex Pharmaceuticals for lectures, presentations, and materials; meeting attendance; and participation on data safety monitoring boards or advisory boards. MAM received payment from Vertex for the current work and personal fees for serving on an advisory board; grants from Vertex and from the German Ministry for Education and Research; consulting fees from Boehringer Ingelheim, Arrowhead Pharmaceuticals, Vertex Pharmaceuticals, Santhera, Sterna Biologicals, Enterprise Therapeutics, Antabio, and Abbvie; lecture fees from Boehringer Ingelheim, Arrowhead Pharmaceuticals, and Vertex Pharmaceuticals; travel reimbursement from Boehringer Ingelheim and Vertex Pharmaceuticals; personal fees for participation in an advisory board from Boehringer Ingelheim, Arrowhead Pharmaceuticals, Vertex Pharmaceuticals, Santhera, Enterprise Therapeutics, Antabio, Kither Biotech, Abbvie, and Pari; and serves as an ECFS Board member. EFM received grants and other payments or honoraria from Vertex; and support for meetings or travel from Menarini. BWR received payments from Vertex for the present work, and payments for a presentation in Vancouver, BC, Canada in 2019; and participated on data safety monitoring boards or advisory boards for CF Storm Clinical Trial, Vertex Pharmaceuticals, Janssen, Abbvie, and Insmed. SMR received support for a clinical trial; consulting fees on the design and conduct of clinical trials; support for meeting attendance and for his role as Co-Chair of the Next Generation Steering Committee; received grants or contracts from Novartis, TranslateBio, Galapagos–Abbvie, Synedgen–Synspira, Eloxx, Vertex Pharmaceuticals, and Ionis Astra Zenica; consulting fees from Novartis, Galapagos–Abbvie, Synedgen–Synspira, Vertex Pharmaceuticals, Renovion, Ionis, Cystetic Medicines, and Arcturus; support for meeting attendance from Vertex; has patents planned, issued or pending; serves as a Co-Chair of the Next Generation Steering Committee; and owns stock or stock options with Synedgen–Synspira and Renovion. RCR received clinical trial support and consulting fees from Vertex for the present work; grants from CFF, NIDDK, NHLBI, NICHD, and NIDCD; received consulting fees from Guidepoint Global, Gerson Lehrman Group, and Cystic Fibrosis Foundation; participated on a data safety monitoring or advisory board for NHLBI DSMB. JLT-C received personal consulting fees from Vertex for the present work; received grants from Vertex, Eloxx, and 4DMT for the conduct of a research trial; personal fees from Vertex, Insmed, and 4DMT for trial design consulting; personal fees from Vertex for non-branded speaking; and personal fees from AbbVie for her role as DMC Chair; served as the adult patient care representative to the CFF Board of Trustees, on the CF Foundation's Clinical Research Executive Committee, Clinical Research Advisory Board, and Racial Justice Working Group; as immediate past chair of the CF TDN's Sexual Health, Reproduction and Gender Research Working Group; on the scientific advisory board for Emily's Entourage; on the ATS Respiratory Health Awards Working Group; on the ATS Scientific Grant Review and Clinical Problems Assembly Programming Committees; and served as an associate editor for the Journal of Cystic Fibrosis. ET received payment for the present work and grants for doing clinical trials from Vertex Pharmaceuticals; received payment and reimbursement from Vertex for her role on a steering committee and for presentations at educational events. JB received funding from Vertex Pharmaceuticals for the present work. AH received funding from Vertex Pharmaceuticals for the present work; grant support from NIHR, CF Trust, CF Foundation, and Medical Research Council; payments for educational lectures from Vertex Pharmaceuticals and for an advisory board from Mylan; medical writing support from Vertex; served as Chair of the UK CF Clinical Trials Accelerator Platform and as a board member of the UK CF Medical Association. LMY received salary support from mgH TDN for clinical research activity for the present work. DW has patents planned, issued or pending. DW, LTW, CC, APM, NN, PRS, ST, FVG, and YX are Vertex employees and might own stocks or stock options. GM and CK have nothing to disclose. LV was a clinical pharmacology lead at Vertex during the conduct of this study and conducted PK data analysis for the present study., (Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

BackgroundLung infections are among the most consequential manifestations of cystic fibrosis (CF) and are associated with reduced lung function and shortened survival. Drugs called CF transmembrane conductance regulator (CFTR) modulators improve activity of dysfunctional CFTR channels, which is the physiological defect causing CF. However, it is unclear how improved CFTR activity affects CF lung infections.MethodsWe performed a prospective, multicenter, observational study to measure the effect of the newest and most effective CFTR modulator, elexacaftor/tezacaftor/ivacaftor (ETI), on CF lung infections. We studied sputum from 236 people with CF during their first 6 months of ETI using bacterial cultures, PCR, and sequencing.ResultsMean sputum densities of Staphylococcus aureus, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Achromobacter spp., and Burkholderia spp. decreased by 2-3 log10 CFU/mL after 1 month of ETI. However, most participants remained culture positive for the pathogens cultured from their sputum before starting ETI. In those becoming culture negative after ETI, the pathogens present before treatment were often still detectable by PCR months after sputum converted to culture negative. Sequence-based analyses confirmed large reductions in CF pathogen genera, but other bacteria detected in sputum were largely unchanged. ETI treatment increased average sputum bacterial diversity and produced consistent shifts in sputum bacterial composition. However, these changes were caused by ETI-mediated decreases in CF pathogen abundance rather than changes in other bacteria.ConclusionsTreatment with the most effective CFTR modulator currently available produced large and rapid reductions in traditional CF pathogens in sputum, but most participants remain infected with the pathogens present before modulator treatment.Trial RegistrationClinicalTrials.gov NCT04038047.FundingThe Cystic Fibrosis Foundation and the NIH.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a crucial ion channel for transport of chloride and bicarbonate anions. Functional roles of CFTR have been identified in a broad range of cell types including epithelial, endothelial, immune and structural cells. While CFTR has been investigated largely in the context of inborn dysfunction in cystic fibrosis, recent evidence shows that CFTR is also affected by acquired dysfunction in COPD. In patients with COPD and smokers, CFTR impairment has been demonstrated in the upper and lower airways, sweat glands and intestines, suggesting both pulmonary and systemic defects. Cigarette smoke, a key factor in COPD development, is the major cause of acquired CFTR dysfunction. Inflammation, bacterial byproducts and reactive oxygen species can further impair CFTR expression and function. CFTR dysfunction could contribute directly to disease manifestation and progression of COPD including disturbed airway surface liquid homeostasis, airway mucus obstruction, pathogen colonisation and inflammation. Mucus plugging and neutrophilic inflammation contribute to tissue destruction, development of dysfunction at the level of the small airways and COPD progression. Acquired CFTR dysfunction in extrapulmonary organs could add to common comorbidities and the disease burden. This review explores how CFTR dysfunction may be acquired and its potential effects on patients with COPD, particularly those with chronic bronchitis. The development of CFTR potentiators and the probable benefits of CFTR potentiation to improve tissue homeostasis, reduce inflammation, improve host defence and potentially reduce remodelling in the lungs will be discussed., Competing Interests: Conflict of interest: M.A. Mall declares editorial support from Novartis Pharma AG since the initial planning of the work, and declares grants from German Ministry for Education and Research and the German Research Foundation, consulting fees from Abbvie, Antabio, Boehringer Ingelheim, Enterprise Therapeutics, Kither Biotech, Pieris Pharmaceuticals, Santhera, Sterna Biologicals and Vertex Paharmaceuticals, lecture fees from Arrowhead Pharmaceuticals, Boehringer Ingelheim and Vertex Pharmaceuticals, travel reimbursement from Boehringer Ingelheim and Vertex Pharmaceuticals, and personal fees for participation on advisory boards from Boehringer Ingelheim, Arrowhead Pharmaceuticals, Vertex Pharmaceuticals, Santhera, Enterprise Therapeutics, Antabio, Kither Biotech and Abbvie; until 2020, M.A. Mall was also an elected unpaid member of the ECFS board. G.J. Criner has no declarations. In the past 36 months, M. Miravitlles has received consulting fees from AstraZeneca, Atriva Therapeutics, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Bial, Gebro Pharma, CSL Behring, Inhibrx, Laboratorios Esteve, Ferrer, Mereo Biopharma, Verona Pharma, Spin Therapeutics, ONO Pharma, pH Pharma, Palobiofarma SL, Takeda, Novartis, Sanofi and Grifols, speaker fees from AstraZeneca, GlaxoSmithKline, Boehringer Ingelheim, Chiesi, Cipla, Menarini, Rovi, Bial, Sandoz, Zambon, CSL Behring, Grifols and Novartis, support for attending meetings/travel from Novartis, Boehringer Ingelheim and Menarini, research grants from Grifols, and has participated on a data safety monitoring board for Mereo. S.M. Rowe declares grant support for clinical trials conducted through university grants/contracts, consulting services on the design and conduct of clinical trials and support for travel to attend meetings from Novartis; support for clinical trials conduct through university grants/contracts, consulting services on the design and conduct of clinical trials, support for travel to attend meetings, co-chair of the Next Generation Steering Committee and providing research product for investigator initiated research from Vertex; grant support for clinical trials conducted through university grants/contracts, consulting services on the design and conduct of clinical trials, material transfer agreements (MTAs) for investigator-initiated and externally funded research efforts from Galapagos/Abbvie since the initial planning of the work; grant support for clinical trials conducted through university grants/contracts from Bayer, TranslateBio and Proteostasis; research grants through university grants/contracts from Synedgen/Synspira; research contract through university grants/contracts from Celtaxsys, Arrowhead, Ionis and AstraZeneca; research contract through university grants/contracts from Eloxx; declares consulting services on the design and conduct of clinical trials from Bayer, Renovion, Arrowhead, Ionis, Cystetic Medicines, Arcturus and Synedgen/Synspira, including stock options for Synedgen/Synspira within the past 36 months; receipt of research products for investigator initiated research from Renovion; MTA agreements for research efforts from Proteostasis; MTAs for investigator-initiated and externally funded research efforts from Ionis, Galapagos/Abbvie and Synedgen/Synspira; all in the past 36 months; and declares six patents. C.F. Vogelmeier declares institution grants from German Ministry of Education and Science (BMBF), AstraZeneca, Boehringer Ingelheim, Chiesi, CSL Behring, GlaxoSmithKline, Grifols and Novartis, consulting fees from Aerogen, AstraZeneca, Boehringer Ingelheim, CSL Behring, Chiesi, GlaxoSmithKline, Insmed, Menarini, Novartis and Nuvaira, and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Aerogen, AstraZeneca, Boehringer Ingelheim, CSL Behring, Chiesi, GlaxoSmithKline, Insmed, Menarini and Novartis, in the past 36 months. D.J. Rowlands is an employee of Novartis Pharma AG and retains Novartis stock. M. Schoenberger is a full-time employee of Novartis Pharma AG and retains Novartis stock. P. Altman is a full-time employee of Novartis Pharmaceutical Corporation., (Copyright ©The authors 2023.)

The coronavirus disease (COVID-19) pandemic, caused by SARS-CoV-2 coronavirus, is devastatingly impacting human health. A prominent component of COVID-19 is the infection and destruction of the ciliated respiratory cells, which perpetuates dissemination and disrupts protective mucociliary transport (MCT) function, an innate defense of the respiratory tract. Thus, drugs that augment MCT could improve the barrier function of the airway epithelium and reduce viral replication and, ultimately, COVID-19 outcomes. We tested five agents known to increase MCT through distinct mechanisms for activity against SARS-CoV-2 infection using a model of human respiratory epithelial cells terminally differentiated in an air/liquid interphase. Three of the five mucoactive compounds tested showed significant inhibitory activity against SARS-CoV-2 replication. An archetype mucoactive agent, ARINA-1, blocked viral replication and therefore epithelial cell injury; thus, it was further studied using biochemical, genetic, and biophysical methods to ascertain the mechanism of action via the improvement of MCT. ARINA-1 antiviral activity was dependent on enhancing the MCT cellular response, since terminal differentiation, intact ciliary expression, and motion were required for ARINA-1-mediated anti-SARS-CoV2 protection. Ultimately, we showed that the improvement of cilia movement was caused by ARINA-1-mediated regulation of the redox state of the intracellular environment, which benefited MCT. Our study indicates that intact MCT reduces SARS-CoV-2 infection, and its pharmacologic activation may be effective as an anti-COVID-19 treatment.

Background: Elexacaftor/tezacaftor/ivacaftor (ETI) improves pulmonary disease in people with cystic fibrosis (PwCF), but its effect on gastrointestinal symptoms, which also affect quality of life, is not clear., Methods: PROMISE is a 56-center prospective, observational study of ETI in PwCF >12 years and at least one F508del allele. Gastrointestinal symptoms, evaluated by validated questionnaires: Patient Assessment of Upper Gastrointestinal Disorders-Symptom (PAGI-SYM), Patient Assessment of Constipation-Symptom (PAC-SYM), Patient Assessment of Constipation-Quality of Life (PAC-QOL)), fecal calprotectin, steatocrit and elastase-1 were measured before and 6 months after ETI initiation. Mean difference and 95% confidence intervals were obtained from linear regression with adjustment for age and sex., Results: 438 participants fully completed at least 1 questionnaire. Mean (SD) for baseline PAGI-SYM, PAC-SYM, and PAC-QOL total scores were 0.56 (0.59), 0.47 (0.45), and 0.69 (0.53) out of maximum 5, 4, and 5, respectively (higher score indicates greater severity). Corresponding age- and sex-adjusted 6 months mean changes (95% CI) in total scores were -0.15 (-0.21, -0.09) for PAGI-SYM, -0.14 (-0.19, -0.09) for PAC-SYM, and -0.15 (-0.21, -0.10) for PAC-QOL. While statistically significant, changes were small and unlikely to be of clinical importance. Fecal calprotectin showed a change (95% CI) from baseline of -66.2 µg/g (-86.1, -46.2) at 6 months, while fecal elastase and steatocrit did not meaningfully change., Conclusions: After 6 months of ETI, fecal markers of inflammation decreased. Gastrointestinal symptoms improved, but the effect size was small. Pancreatic insufficiency did not improve., Competing Interests: Declaration of Competing Interest SJS-Consultant for UpToDate, Abbvie, Mirium, Nestle; Grant funding from Gilead, Cystic Fibrosis Foundation, NIH. SDF – Consultant for UpToDate, Abbvie, Nestle, Synspira; Grant funding from NIH, Cystic Fibrosis Foundation, Amagma Therapeutics. MRN – Consultant for UpToDate, Vertex: Grant funding from Gilead, AbbVie, Cystic Fibrosis Foundation, NIH SMR: Consultant for Vertex; Grant funding from Vertex, Cystic Fibrosis Foundation, NIH DPN: Consultant for Vertex, Genentech; Grant funding from Vertex, Cystic Fibrosis Foundation, NIH GMS: Consultant for Genentech, Electromed; Grant Funding from Vertex, Cystic Fibrosis Foundation, NIH DG: Consultant for Vertex, Abbvie, Chiesi USA, Eli Lilly AK: Grant funding from NIH, Cystic Fibrosis Foundation, SDS – Grant funding from Cystic Fibrosis Foundation and NIH MSS—Grant funding from Cystic Fibrosis Foundation, (Copyright © 2022. Published by Elsevier B.V.)

Mucopolysaccharidosis I-Hurler (MPS I-H) is caused by the loss of α-L-iduronidase, a lysosomal enzyme that degrades glycosaminoglycans. Current therapies cannot treat many MPS I-H manifestations. In this study, triamterene, an FDA-approved, antihypertensive diuretic, was found to suppress translation termination at a nonsense mutation associated with MPS I-H. Triamterene rescued enough α-L-iduronidase function to normalize glycosaminoglycan storage in cell and animal models. This new function of triamterene operates through premature termination codon (PTC) dependent mechanisms that are unaffected by epithelial sodium channel activity, the target of triamterene's diuretic function. Triamterene represents a potential non-invasive treatment for MPS I-H patients carrying a PTC., Competing Interests: A.S., M.D., J.R.B., S.M.R., D.M.B. and K.M.K. are named in an unlicensed patent for the use of triamterene as a translational readthrough agent. S.M.R. and D.M.B. provided consulting services and received grants from PTC Therapeutics, Incorporated.

Substantial clinical evidence supports the notion that ciliary function in the airways is important in COVID-19 pathogenesis. Although ciliary damage has been observed in both in vitro and in vivo models, the extent or nature of impairment of mucociliary transport (MCT) in in vivo models remains unknown. We hypothesize that SARS-CoV-2 infection results in MCT deficiency in the airways of golden Syrian hamsters that precedes pathological injury in lung parenchyma. Micro-optical coherence tomography was used to quantitate functional changes in the MCT apparatus. Both genomic and subgenomic viral RNA pathological and physiological changes were monitored in parallel. We show that SARS-CoV-2 infection caused a 67% decrease in MCT rate as early as 2 days postinfection (dpi) in hamsters, principally due to 79% diminished airway coverage of motile cilia. Correlating quantitation of physiological, virological, and pathological changes reveals steadily descending infection from the upper airways to lower airways to lung parenchyma within 7 dpi. Our results indicate that functional deficits of the MCT apparatus are a key aspect of COVID-19 pathogenesis, may extend viral retention, and could pose a risk factor for secondary infection. Clinically, monitoring abnormal ciliated cell function may indicate disease progression. Therapies directed toward the MCT apparatus deserve further investigation.

Cystic fibrosis (CF), first described in 1938, is a common, life-limiting monogenetic disease. The discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 1989 was crucial in advancing our understanding of disease pathogenesis and paving the road for treatment aimed at the fundamental molecular defect. With the delineation of over 2000 variations in the CFTR gene, a sound understanding of the individual variations in cell biology, and electrophysiological abnormalities conferred by the most common defects propelled the advent of targeted disease-modifying therapeutics beginning in 2012. Since then, CF care has transformed beyond just symptomatic treatment to include a variety of small-molecule therapies that address the basic electrophysiologic defect and cause profound improvements in physiology, clinical manifestations, and long-term outcomes, designed to differentially address six genetic/molecular subtypes. This chapter illustrates the progress made toward how fundamental science and translational initiatives enabled personalized, mutation specific treatment. We highlight the importance of preclinical assays and mechanistically-driven development strategies that were coupled with sensitive biomarkers and a clinical trial cooperative to provide a platform for successful drug development. This convergence of academic and private partnerships, and formation of multidisciplinary care teams directed by evidence-based initiatives provide a seminal example of addressing the needs of individuals with a rare, but fatal genetic disease., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ferret systemic coronavirus (FRSCV) causes a highly fatal disease of ferrets ( Mustela putorius furo ). It is believed to be a mutated variant of ferret enteric coronavirus (FRECV) and has a clinical presentation similar to that of feline infectious peritonitis virus (FIPV) in cats. The interplay of infectious diseases and host genetics will become a greater issue in the research environment as genetically modified species other than rodents become available due to advances in gene editing technology. In this case series, we present the clinical and histopathologic features of a FRSCV outbreak that affected 5 out of 10 ferrets with α-1 antitrypsin knockout (AAT KO) over an approximately 1-y period. Clinical features varied, with the affected ferrets presenting with some combination of wasting, hind limb paralysis, incontinence or sudden death. Multiple ferrets had gross pathologic lesions consistent with FRSCV, but the lesions were typically mild. Microscopic pyogranulomatous inflammation was present in 4 ferrets. Immunohistochemistry using an anti-feline coronavirus antibody that cross reacts with ferret coronavirus confirmed infection of intralesional macrophages in 4 out of 5 animals with suspected FRSCV infection. PCR testing of formalin fixed tissue was negative for all ferrets. PCR testing of feces from healthy wild-type ferrets indicated that the endemic presence of FRECV genotype 2, while PCR surveillance testing of other in-house AAT KO ferrets revealed both enteric coronavirus genotypes 1 and 2. This case series highlights the potential for greater disease incidence in the future as genetically modified ferrets are used more often, and may support exclusion of FRECV and similar viruses from highly susceptible ferret genotypes.

Our current understanding of the spectrum of TB and COVID-19 lesions in the human lung is limited by a reliance on low-resolution imaging platforms that cannot provide accurate 3D representations of lesion types within the context of the whole lung. To characterize TB and COVID-19 lesions in 3D, we applied micro/nanocomputed tomography to surgically resected, postmortem, and paraffin-embedded human lung tissue. We define a spectrum of TB pathologies, including cavitary lesions, calcium deposits outside and inside necrotic granulomas and mycetomas, and vascular rearrangement. We identified an unusual spatial arrangement of vasculature within an entire COVID-19 lobe, and 3D segmentation of blood vessels revealed microangiopathy associated with hemorrhage. Notably, segmentation of pathological anomalies reveals hidden pathological structures that might otherwise be disregarded, demonstrating a powerful method to visualize pathologies in 3D in TB lung tissue and whole COVID-19 lobes. These findings provide unexpected new insight into the spatial organization of the spectrum of TB and COVID-19 lesions within the framework of the entire lung., (© 2022 The Authors. Published under the terms of the CC BY 4.0 license.)

The spectrum of disorders involving CFTR (cystic fibrosis transmembrane conductance regulator) dysfunction correlates with a continuous gradient of CFTR function defined by the combination of two allelic CFTR variants. CFTR-related disorders are clinical entities with features of cystic fibrosis (CF) and evidence for presence of CFTR dysfunction but not meeting criteria for diagnosis of CF. Individuals with CFTR-RDs demonstrate a wide range of CFTR activity and are still under-recognized or misclassified. The level of CFTR dysfunction may be measured in vivo (sweat testing, nasal potential difference measurements) and/or by ex vivo tests (intestinal current measurement), or indirectly indicated by CFTR variants, as alteration in sequence of the CFTR gene translates into CFTR dysfunction. CFTR bioassays can aid in the diagnosis of individuals with CF, but we lack parameters to differentiate CF from CFTR-RD. In the era of the CFTR modulators and their potential clinical benefit, it is of utmost importance to diagnose CFTR-RD as unambiguously as possible. We therefore propose the following to define compatible CFTR dysfunction in a person with a suspected diagnosis of CFTR-RD : (1) evidence of CFTR dysfunction in vivo or ex vivo in at least two different CFTR functional test types, or (2) One CFTR variant known to reduce CFTR function and evidence of CFTR dysfunction in vivo or ex vivo in at least two different CFTR functional test types, or (3) Two CFTR variants shown to reduce CFTR function, with at most one CF-causing variant., Competing Interests: Declaration of Competing Interest All the authors have declared their conflict of interests., (Copyright © 2022. Published by Elsevier B.V.)

Airway dehydration causes mucus stasis and bacterial overgrowth in cystic fibrosis (CF), resulting in recurrent respiratory infections and exacerbations. Strategies to rehydrate airway mucus including inhibition of the epithelial sodium channel (ENaC) have the potential to improve mucosal defense by enhancing mucociliary clearance (MCC) and reducing the risk of progressive decline in lung function. In the current work, we evaluated the effects of AZD5634, an ENaC inhibitor that shows extended lung retention and safety profile as compared with previously evaluated candidate drugs, in healthy and CF preclinical model systems. We found that AZD5634 elicited a potent inhibition of amiloride-sensitive current in non-CF airway cells and airway cells derived from F508del-homozygous individuals with CF that effectively increased airway surface liquid volume and improved mucociliary transport (MCT) rate. AZD5634 also demonstrated efficacious inhibition of ENaC in sheep bronchial epithelial cells, translating to dose-dependent improvement of mucus clearance in healthy sheep in vivo. Conversely, nebulization of AZD5634 did not notably improve airway hydration or MCT in CF rats that exhibit an MCC defect, consistent with findings from a first single-dose evaluation of AZD5634 on MCC in people with CF. Overall, these findings suggest that CF animal models demonstrating impaired mucus clearance translatable to the human situation may help to successfully predict and promote the successful translation of ENaC-directed therapies to the clinic.

Access to cystic fibrosis transmembrane conductance regulator (CFTR) modulators has been gradually increasing for people with cystic fibrosis, the first of which was ivacaftor, a CFTR potentiator that is part of all clinically available modulator treatments. In this study, we hypothesized that the steady-state concentrations in blood and tissue are highly variable in patients taking ivacaftor in a real-world context, which may have an impact on the treatment approach. We collected nasal epithelial cells to estimate target site concentrations and blood samples to estimate pharmacokinetic parameters at a steady state. We found that patients on ivacaftor monotherapy have variable concentrations well above the maximal effective concentration and may maintain concentrations necessary for the clinical benefit even if dosing is reduced. We also are the first to provide detailed target site concentration data over time, which shows that tissue concentrations do not fluctuate significantly and do not correlate with plasma concentrations. These findings show that some patients may have higher-than-expected concentrations and may benefit from tailored dosing to balance clinical response with side effects or adherence needs., (© 2022 Wiley Periodicals LLC.)

Background: Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator for people with CF and the G551D mutation. We aimed to investigate the biology of CFTR modulation and systemic effects of CFTR restoration by examining changes in circulating measurements of inflammation and growth and novel proteins with ivacaftor treatment., Methods: Blood samples from 64 CF subjects with G551D-CFTR were analyzed for inflammatory and growth-related proteins at baseline, 1 and 6 months after ivacaftor initiation. In 30 subjects, plasma was assayed for 1,322 proteins using the SomaScan proteomic platform at baseline and 6 months post-ivacaftor. Correlations with clinical outcomes were assessed., Measurements and Main Results: Significant reductions in high mobility group box-1 protein (HMGB-1), calprotectin, serum amyloid A, and granulocyte colony-stimulating factor (G-CSF), and an increase in insulin-like growth factor (IGF-1) occurred 1 month after ivacaftor. This treatment effect was sustained at 6 months for HMGB-1 and calprotectin. Correcting for multiple comparisons in the proteomic analysis, 9 proteins (albumin, afamin, leptin, trypsin, pancreatic stone protein [PSP], pituitary adenylate cyclase-activating polypeptide-38, repulsive guidance molecule A [RGMA], calreticulin, GTPase KRas) changed significantly with ivacaftor. Proteins changing with treatment are involved in lipid digestion and transport and extracellular matrix organization biological processes. Reductions in calprotectin and G-CSF and increases in calreticulin, and RGMA correlated with improved lung function, while increasing IGF-1, leptin and afamin and decreasing PSP correlated with increased weight., Conclusions: Ivacaftor led to changes in inflammatory, lipid digestion, and extracellular matrix proteins, lending insights into the extrapulmonary effects of CFTR modulation., Competing Interests: Conflict of interest statement JEH reports grants from Cystic Fibrosis Foundation, outside the submitted work, SMR reports grants, personal fees, non-financial support and other from Vertex Pharmaceuticals Inc., during the conduct of the study; grants and personal fees from Novartis, grants and personal fees from Bayer, grants from Translate Bio, non-financial support from Proteostasis, grants, personal fees and non-financial support from Galapagos/Abbvie, grants, personal fees and other from Synedgen/Synspira, grants from Eloxx, grants and personal fees from Celtaxsys, grants, personal fees, non-financial support and other from Vertex Pharmaceuticals Inc, personal fees from Renovion, grants and personal fees from Arrowhead, grants and other from Ionis, grants from Astra Zenica, personal fees from Cystetic Medicines, personal fees from Arcturus, outside the submitted work; EMD reports other from EvoEndoscopy (formerly Triple Endoscopy), outside the submitted work and is a consultant for Boehringer Ingelheim, not related to this work. SDS reports grants from the Cystic Fibrosis Foundation that funds the work under consideration, and grants from the Cystic Fibrosis Foundation and National Institutes of Health funding activities outside the submitted work. BDW, JKH and SLH have nothing to disclose., (Copyright © 2022 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: Chronic obstructive pulmonary disease (COPD) is a progressive lung disease with poor treatment options. However, most mouse models of COPD produce a primarily emphysematous disease not recapitulating clinically meaningful COPD features like chronic bronchitis., Methods: Wild-type ferrets (Mustela putorius furo) were divided randomly into two groups: whole body cigarette smoke exposure and air controls. Ferrets were exposed to smoke from 1R6F research cigarettes, twice daily for six months. RNA-sequencing was performed on RNA isolated from lung tissue. Comparative transcriptomics analyses of COPD in ferrets, mice, and humans were done to find the uniquely expressed genes. Further, Real-time PCR was performed to confirmed RNA-Seq data on multiple selected genes., Results: RNA-sequence analysis identified 420 differentially expressed genes (DEGs) that were associated with the development of COPD in ferrets. By comparative analysis, we identified 25 DEGs that are uniquely expressed in ferrets and humans, but not mice. Among DEGs, a number were related to mucociliary clearance (NEK-6, HAS1, and KL), while others have been correlated with abnormal lung function (IL-18), inflammation (TREM1, CTSB), or oxidative stress (SRX1, AHRR). Multiple cellular pathways were aberrantly altered in the COPD ferret model, including pathways associated with COPD pathogenesis in humans. Validation of these selected unique DEGs using real-time PCR demonstrated > absolute 2-fold changes in mRNA versus air controls, consistent with RNA-seq analysis., Conclusion: Cigarette smoke-induced COPD in ferrets modulates gene expression consistent with human COPD and suggests that the ferret model may be uniquely well suited for the study of aspects of the disease., (© 2022. The Author(s).)

Cystic fibrosis airway disease is characterised by chronic Pseudomonas aeruginosa infection. Successful eradication strategies have been hampered by a poor understanding of the mechanisms underlying conversion to chronicity. The cystic fibrosis transmembrane conductance receptor (CFTR)-knockout (KO) rat harbours a progressive defect in mucociliary transport and viscosity. KO rats were infected before and after the appearance of the mucus defect, using a clinical mucoid-isolate of P. aeruginosa embedded in agarose beads. Young KO rats that were exposed to bacteria before the development of mucociliary transport defects resolved the infection and subsequent tissue damage. However, older KO rats that were infected in the presence of hyperviscous and static mucus were unable to eradicate bacteria, but instead had bacterial persistence through 28 days post-infection that was accompanied by airway mucus occlusion and lingering inflammation. Normal rats responded to infection with increased mucociliary transport to supernormal rates, which reduced the severity of a second bacterial exposure. We conclude that the aberrant mucus present in the CF airway permits persistence of P. aeruginosa in the lung., Competing Interests: Conflict of interest: A.G. Henderson has nothing to disclose. Conflict of interest: J.M. Davis has nothing to disclose. Conflict of interest: J.D. Keith has nothing to disclose. Conflict of interest: M.E. Green has nothing to disclose. Conflict of interest: A.M. Oden has nothing to disclose. Conflict of interest: S.M. Rowe has a patent “Use of μOCT as a tool for diagnosis and drug discovery” issued. Conflict of interest: S.E. Birket reports grants from NIH NHLBI and Cystic Fibrosis Foundation, during the conduct of the study., (Copyright ©The authors 2022. For reproduction rights and permissions contact permissions@ersnet.org.)

Purpose: To describe a case of increased viral load in a patient with HIV-1 infection receiving treatment with crushed bictegravir/emtricitabine/tenofovir alafenamide (B/FTC/TAF)., Summary: A 43-year-old man, newly diagnosed with HIV, was hospitalized due to failure to thrive, neurological changes, and hypotension. Before treatment, the HIV viral load (VL) was 769,704 copies/mL and the CD4+ T-cell count was 36 cells/μL. On hospital day (HD) 8, B/FTC/TAF by mouth daily was initiated. During the hospitalization, the patient's course was complicated by opportunistic infections, bilateral pneumothorax, seizure activity, and acute respiratory distress, requiring multiple intubations and extended time in the intensive care unit. A repeat VL measurement on HD 28 was 5,887 copies/mL after the patient had received 14 of 20 scheduled B/FTC/TAF doses. Because of a failed swallow study and continued nutritional deficits, a percutaneous endoscopic gastrostomy (PEG) tube was placed on HD 38 and continuous tube feeds via the PEG tube were initiated. Subsequently, the B/FTC/TAF order was modified to be crushed, mixed in 30 mL water, and administered daily via the PEG tube. A repeat VL measurement on HD 65 showed an increase to 8,047 copies/mL, despite receipt of 37 consecutive doses of B/FTC/TAF. B/FTC/TAF was discontinued and dolutegravir 50 mg twice daily, darunavir 800 mg plus ritonavir 100 mg (DRV/r), and tenofovir disoproxil fumarate/FTC 300 mg/200 mg were started due to virological increase, need for a viable option compatible with PEG tube delivery, and potential for integrase inhibitor resistance. At the time of regimen change (HD 67), a resistance panel showed minor mutations, E157Q and V118I. The regimen was streamlined with discontinuation of DRV/r on HD 92. The patient was discharged on HD 161. The PEG tube was removed 2 months after discharge, oral B/FTC/TAF was reinitiated, and the patient was virologically suppressed at 1 year after discharge., Conclusion: Controlled studies are needed to verify acceptable pharmacokinetic and pharmacodynamic metrics for crushed B/FTC/TAF given via tube, with and without tube feeds, before use in this manner., (© American Society of Health-System Pharmacists 2022. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Inhaled gene therapy of muco-obstructive lung diseases requires a strategy to achieve therapeutically relevant gene transfer to airway epithelium covered by particularly dehydrated and condensed mucus gel layer. Here, we introduce a synthetic DNA-loaded mucus-penetrating particle (DNA-MPP) capable of providing safe, widespread and robust transgene expression in in vivo and in vitro models of muco-obstructive lung diseases., Methods: We investigated the ability of DNA-MPP to mediate reporter and/or therapeutic transgene expression in lung airways of a transgenic mouse model of muco-obstructive lung diseases (ie, Scnn1b -Tg) and in air-liquid interface cultures of primary human bronchial epithelial cells harvested from an individual with cystic fibrosis. A plasmid designed to silence epithelial sodium channel (ENaC) hyperactivity, which causes airway surface dehydration and mucus stasis, was intratracheally administered via DNA-MPP to evaluate therapeutic effects in vivo with or without pretreatment with hypertonic saline, a clinically used mucus-rehydrating agent., Results: DNA-MPP exhibited marked greater reporter transgene expression compared with a mucus-impermeable formulation in in vivo and in vitro models of muco-obstructive lung diseases. DNA-MPP carrying ENaC-silencing plasmids provided efficient downregulation of ENaC and reduction of mucus burden in the lungs of Scnn1b -Tg mice, and synergistic impacts on both gene transfer efficacy and therapeutic effects were achieved when DNA-MPP was adjuvanted with hypertonic saline., Discussion: DNA-MPP constitutes one of the rare gene delivery systems providing therapeutically meaningful gene transfer efficacy in highly relevant in vivo and in vitro models of muco-obstructive lung diseases due to its unique ability to efficiently penetrate airway mucus., Competing Interests: Competing interests: The mucus-penetrating particle technology described in this publication has been developed at the Johns Hopkins University and is currently licensed to Kala Pharmaceuticals. JH is a founder of Kala Pharmaceuticals and currently serves as a consultant. JH and Johns Hopkins University own company stock; JH’s relationship with Kala Pharmaceuticals is subject to certain restrictions under university policy. The terms of this arrangement are being managed by the Johns Hopkins University in accordance with its conflict of interest policies., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Rationale: The majority of chronic obstructive pulmonary disease (COPD) patients have chronic bronchitis, for which specific therapies are unavailable. Acquired cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction is observed in chronic bronchitis, but has not been proven in a controlled animal model with airway disease. Furthermore, the potential of CFTR as a therapeutic target has not been tested in vivo, given limitations to rodent models of COPD. Ferrets exhibit cystic fibrosis-related lung pathology when CFTR is absent and COPD with bronchitis following cigarette smoke exposure., Objectives: To evaluate CFTR dysfunction induced by smoking and test its pharmacological reversal by a novel CFTR potentiator, GLPG2196, in a ferret model of COPD with chronic bronchitis., Methods: Ferrets were exposed for 6 months to cigarette smoke to induce COPD and chronic bronchitis and then treated with enteral GLPG2196 once daily for 1 month. Electrophysiological measurements of ion transport and CFTR function, assessment of mucociliary function by one-micron optical coherence tomography imaging and particle-tracking microrheology, microcomputed tomography imaging, histopathological analysis and quantification of CFTR protein and mRNA expression were used to evaluate mechanistic and pathophysiological changes., Measurements and Main Results: Following cigarette smoke exposure, ferrets exhibited CFTR dysfunction, increased mucus viscosity, delayed mucociliary clearance, airway wall thickening and airway epithelial hypertrophy. In COPD ferrets, GLPG2196 treatment reversed CFTR dysfunction, increased mucus transport by decreasing mucus viscosity, and reduced bronchial wall thickening and airway epithelial hypertrophy., Conclusions: The pharmacologic reversal of acquired CFTR dysfunction is beneficial against pathological features of chronic bronchitis in a COPD ferret model., Competing Interests: Conflict of interest: S.M. Rowe has received consulting fees from Abbvie related to the design and conduct of clinical trials in cystic fibrosis. M. Borgonovi and K. Conrath are employees of Galapagos. All other authors declare no competing interests., (Copyright ©The authors 2022. For reproduction rights and permissions contact permissions@ersnet.org.)

Background: Alteration of the airway microbiota is a hallmark of cystic fibrosis (CF) pulmonary disease. Dysfunction of cystic fibrosis transmembrane regulator (CFTR) in the intestine also promotes changes in local microbiota such as small intestinal bacterial overgrowth (SIBO), which is common in CF. We evaluated whether therapy with the CFTR modulator combination lumacaftor/ivacaftor (luma/iva) has a beneficial impact on SIBO as measured by breath testing (BT)., Methods: A multicenter longitudinal study of CFTR-dependent disease profiling (NCT02477319) included a prospective evaluation for SIBO by BT. Tidal breath samples were collected after fasting and 15, 30, 45, 60, 90, and 120 minutes after ingestion of glucose, before and 1 month after subjects initiated luma + iva., Results: Forty-two subjects enrolled in the sub-study (mean age = 23.3 years; 51% female; 9.5% Latinx); 38 completed a hydrogen BT at both time points, of which 73.7% had a positive BT before luma/iva (baseline) and 65.8% had a positive test after luma/iva ( P = 0.44); shifts from negative to positive were also seen. Use of azithromycin (63.1%) and inhaled antibiotics (60.5%) were not associated with positive BT. Acid-blocking medications were taken by 73% of those with a negative BT at baseline and by 35% with a positive baseline BT ( P = 0.04)., Conclusion: We found a high rate of positive hydrogen breath tests in individuals with CF, confirming that SIBO is common. One month of luma/iva did not significantly change the proportion of those with positive breath hydrogen measurements., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by European Society for European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Background: Abnormal chloride (Cl - ) transport dehydrates airway surface liquid (ASL) in sinonasal epithelium leading to mucus stasis and chronic rhinosinusitis. As an experimental epithelium, rabbit tissue provides an excellent representation of human sinus disease, and the rabbit sinusitis model is both established and well suited for therapeutic interventions in vivo. Our objective in this study was to evaluate whether ivacaftor reverses the consequences of Pseudomonas aeruginosa-induced acquired cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction., Methods: Rabbit nasal cavities were assessed for responsiveness to ivacaftor in vivo (by nasal potential difference [NPD] assay). Rabbit nasal epithelial (RNE) cultures were incubated with an ultrafiltrate of P aeruginosa (PAO1 strain) for 4 hours and tested for acquired CFTR dysfunction. Markers of mucociliary function, including airway surface liquid depth (ASL), periciliary liquid depth (PCL), ciliary beat frequency (CBF), and mucociliary transport (MCT), were measured by micro-optical coherence tomography (μOCT) after PAO1 and/or ivacaftor incubation., Results: Ivacaftor resulted in a significant mean NPD polarization of 21.8 ± 2.1 mV, which was significantly greater than that seen in the low Cl - control (12.9 ± 1.3; p = 0.01). PAO1 exposure induced a state of acquired CFTR dysfunction in rabbit nasal epithelium as measured by forskolin-stimulated short-circuit current (I SC ) (control, 37.0 ± 1.1 μA/cm 2 ; PAO1, 24.4 ± 1.1 μA/cm 2 ; p < 0.001). RNE cultures exposed to PAO1 had inhibited mucociliary function, whereas coincubation with ivacaftor restored mucociliary clearance, as measured by μOCT., Conclusion: In rabbit nasal epithelium, ivacaftor robustly stimulates CFTR-mediated Cl - secretion and normalizes ASL and CBF in PAO1-induced acquired CFTR dysfunction. Preclinical testing of CFTR potentiators as therapy for P aeruginosa rabbit sinusitis is planned., (© 2021 ARS-AAOA, LLC.)

The human lung differs substantially from its mouse counterpart, resulting in a distinct distal airway architecture affected by disease pathology in chronic obstructive pulmonary disease. In humans, the distal branches of the airway interweave with the alveolar gas-exchange niche, forming an anatomical structure known as the respiratory bronchioles. Owing to the lack of a counterpart in mouse, the cellular and molecular mechanisms that govern respiratory bronchioles in the human lung remain uncharacterized. Here we show that human respiratory bronchioles contain a unique secretory cell population that is distinct from cells in larger proximal airways. Organoid modelling reveals that these respiratory airway secretory (RAS) cells act as unidirectional progenitors for alveolar type 2 cells, which are essential for maintaining and regenerating the alveolar niche. RAS cell lineage differentiation into alveolar type 2 cells is regulated by Notch and Wnt signalling. In chronic obstructive pulmonary disease, RAS cells are altered transcriptionally, corresponding to abnormal alveolar type 2 cell states, which are associated with smoking exposure in both humans and ferrets. These data identify a distinct progenitor in a region of the human lung that is not found in mouse that has a critical role in maintaining the gas-exchange compartment and is altered in chronic lung disease., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Coxiella burnetii causes coxiellosis in animals and Q fever in humans, a potentially debilitating zoonotic disease commonly transmitted through domestic ruminants. To prevent transboundary spread of C. burnetii, animals may be tested prior to export. In alpacas, this process is complicated by the lack of scientific evidence for C. burnetii infection in the species, and the unique composition of camelid antibodies, which may cause false-positive results in assays developed for ruminants. We evaluated a complement fixation test (CFT; currently recommended for alpacas in New Zealand), an enzyme-linked immunosorbent assay (ELISA) and an immunofluorescence assay (IFA). Positive analytical control samples were generated through vaccination of alpacas with a human Q fever vaccine, whereas negative analytical control samples were sourced from New Zealand (deemed free of C. burnetii). Immunological assays were conducted on 131 alpaca sera submitted for export testing. Test characteristics (sensitivity, specificity, positive and negative predictive values) for CFT, ELISA and IFA were determined using Bayesian latent class analysis. Due to anticomplementary activity, 37 (28.2%) of the CFT results were inconclusive, making CFT unsuitable for routine use. Of the remaining 94 samples, 10.6%, 0% and 7.4% were positive for C. burnetii antibodies based on CFT, ELISA and IFA, respectively, yielding estimated sensitivities of 58%, 26% and 78%, and estimated specificities of 95%, 98% and 95%, with the estimates for sensitivity being imprecise, as evidenced by wide 95% credible intervals. Positive predictive values were similar across assays, albeit very low at the estimated seroprevalence of 5%. Our results indicate that, of the tests available, IFA appears to be the most appropriate for use in alpacas. Higher sensitivity of antibody detection, use of antigen detection assays and availability of samples from individuals with evidence of infection could provide additional insight into the risk of transboundary spread of C. burnetii by alpacas., (© 2021 Wiley-VCH GmbH.)

Rationale: The cystic fibrosis (CF) modulator drug, elexacaftor/tezacaftor/ivacaftor (ETI), proved highly effective in controlled clinical trials for individuals with at least one F508del allele, which occurs in at least 85% of people with CF. Objectives: PROMISE is a postapproval study to understand the broad effects of ETI through 30 months' clinical use in a more diverse U.S. patient population with planned analyses after 6 months. Methods: Prospective, observational study in 487 people with CF age 12 years or older with at least one F508del allele starting ETI for the first time. Assessments occurred before and 1, 3, and 6 months into ETI therapy. Outcomes included change in percent predicted FEV 1 (ppFEV 1 ), sweat chloride concentration, body mass index (BMI), and self-reported respiratory symptoms. Measurements and Main Results: Average age was 25.1 years, and 44.1% entered the study using tezacaftor/ivacaftor or lumacaftor/ivacaftor, whereas 6.7% were using ivacaftor, consistent with F508del homozygosity and G551D allele, respectively. At 6 months into ETI therapy, ppFEV 1 improved 9.76 percentage points (95% confidence interval [CI], 8.76 to 10.76) from baseline, cystic fibrosis questionnaire-revised respiratory domain score improved 20.4 points (95% CI, 18.3 to 22.5), and sweat chloride decreased -41.7 mmol/L (95% CI, -43.8 to -39.6). BMI also significantly increased. Changes were larger in those naive to modulators but substantial in all groups, including those treated with ivacaftor at baseline. Conclusions: ETI by clinical prescription provided large improvements in lung function, respiratory symptoms, and BMI in a diverse population naive to modulator drug therapy, using existing two-drug combinations, or using ivacaftor alone. Each group also experienced significant reductions in sweat chloride concentration, which correlated with improved ppFEV 1 in the overall study population. Clinical trial registered with www.clinicaltrials.gov (NCT NCT04038047).

The objectives for this study were to (1) describe the pathogen profile in quarters from cows with clinical mastitis and in cows with subclinical mastitis in southeastern Australia; and (2) describe antimicrobial susceptibility among isolated pathogens. As a secondary objective, we aimed to compare antimicrobial resistance prevalence in pathogens isolated from clinical and subclinical mastitis samples. A convenience sample of dairy herds (n = 65) from 4 regions in southeastern Australia (Gippsland, Northern Victoria, Tasmania, Western Victoria) were invited to submit milk samples from cows with clinical and subclinical mastitis over a 14-mo period (January 2011 to March 2012). Farmers were instructed to collect aseptic quarter milk samples from the first 10 cases of clinical mastitis for each month of the study. In addition, farmers submitted composite milk samples from cows with subclinical mastitis at 1 or 2 sampling occasions during the study period. Aerobic culture and biochemical tests were used to identify isolates. Isolates were classified as susceptible, intermediate, or resistant to a panel of antimicrobial agents based on the zone of growth inhibition around antimicrobial-impregnated disks, with antimicrobial resistance (AMR) classified as nonsusceptibility by combining intermediate and resistant groups into a single category. Generalized linear mixed models were used to compare the prevalence of AMR between clinical and subclinical mastitis isolates. For clinical mastitis samples (n = 3,044), 472 samples (15.5%) were excluded for contamination. Of the remaining samples (n = 2,572), the most common results were Streptococcus uberis (39.2%), no growth (27.5%), Staphylococcus aureus (10.6%), Escherichia coli (8.4%), and Streptococcus dysgalactiae (6.4%). For subclinical mastitis samples (n = 1,072), 425 (39.6%) were excluded due to contamination. Of the remaining samples (n = 647), the most common results were no growth (29.1%), Staph. aureus (29.1%), and Strep. uberis (21.6%). The prevalence of AMR among common isolates was low for the majority of antimicrobial agents. Exploratory analysis found that the probability of Staph. aureus demonstrating resistance to penicillin was 5.16 times higher (95% confidence interval: 1.68, 15.88) in subclinical isolates relative to clinical Staph. aureus isolates. A similar association was observed for amoxicillin with subclinical Staph. aureus isolates being 4.70 times (95% confidence interval: 1.49, 14.75) more likely to be resistant than clinical Staph. aureus isolates. We concluded that the most common bacteria causing clinical mastitis in dairy herds in Australia is likely to be Strep. uberis, whereas Staph. aureus is likely to be the most common cause of subclinical mastitis. Despite decades of antimicrobial use to control these organisms, AMR appears to be uncommon., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Pseudomonas aeruginosa is a common opportunistic pathogen that can cause chronic infections in multiple disease states, including respiratory infections in patients with cystic fibrosis (CF) and non-CF bronchiectasis. Like many opportunists, P. aeruginosa forms multicellular biofilm communities that are widely thought to be an important determinant of bacterial persistence and resistance to antimicrobials and host immune effectors during chronic/recurrent infections. Poly (acetyl, arginyl) glucosamine (PAAG) is a glycopolymer that has antimicrobial activity against a broad range of bacterial species, and also has mucolytic activity, which can normalize the rheological properties of cystic fibrosis mucus. In this study, we sought to evaluate the effect of PAAG on P. aeruginosa bacteria within biofilms in vitro , and in the context of experimental pulmonary infection in a rodent infection model. PAAG treatment caused significant bactericidal activity against P. aeruginosa biofilms, and a reduction in the total biomass of preformed P. aeruginosa biofilms on abiotic surfaces, as well as on the surface of immortalized cystic fibrosis human bronchial epithelial cells. Studies of membrane integrity indicated that PAAG causes changes to P. aeruginosa cell morphology and dysregulates membrane polarity. PAAG treatment reduced infection and consequent tissue inflammation in experimental P. aeruginosa rat infections. Based on these findings we conclude that PAAG represents a novel means to combat P. aeruginosa infection, and may warrant further evaluation as a therapeutic.

CFTR function is required for normal mucociliary clearance (MCC) and cough-assisted clearance (CC). Lumacaftor-ivacaftor is approved for use in people with cystic fibrosis (CF) carrying two copies of F508del-CFTR. In this observational study performed at four study sites, we characterized the effect of lumacaftor-ivacaftor on mucociliary and cough clearance and related this to other clinical and research endpoints after one month of treatment. Twenty-five adolescents and adults were enrolled. No effect on whole lung MCC was observed, but CC was significantly increased. Sweat chloride improved by 18 mEq/L in this group, indicating a modest restoration of CFTR activity, but no demonstrable change in FEV 1 or lung clearance index was observed. We speculate that the modest effect of lumacaftor-ivacaftor on CFTR function was insufficient to yield an improvement in MCC., (Copyright © 2021 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

The ABC multidrug exporter MsbA mediates the translocation of lipopolysaccharides and phospholipids across the plasma membrane in Gram-negative bacteria. Although MsbA is structurally well characterised, the energetic requirements of lipid transport remain unknown. Here, we report that, similar to the transport of small-molecule antibiotics and cytotoxic agents, the flopping of physiologically relevant long-acyl-chain 1,2-dioleoyl (C18)-phosphatidylethanolamine in proteoliposomes requires the simultaneous input of ATP binding and hydrolysis and the chemical proton gradient as sources of metabolic energy. In contrast, the flopping of the large hexa-acylated (C12-C14) Lipid-A anchor of lipopolysaccharides is only ATP dependent. This study demonstrates that the energetics of lipid transport by MsbA is lipid dependent. As our mutational analyses indicate lipid and drug transport via the central binding chamber in MsbA, the lipid availability in the membrane can affect the drug transport activity and vice versa., (© 2021. The Author(s).)

Background: The Characterizing CFTR Modulated Changes in Sweat Chloride and their Association with Clinical Outcomes (CHEC-SC) study is a large epidemiologic study designed to determine the relationship between sweat chloride response and clinical outcomes in people with cystic fibrosis (CF) on commercially approved CFTR modulators. A challenge to study feasibility was capturing sweat chloride measurements before modulator initiation. We tested the hypothesis that historic sweat chloride approximated contemporary pre-modulator values to estimate CFTR modulator-induced changes, allowing a single-visit study design., Methods: GOAL and PROSPECT were multi-center prospective studies of individuals initiating ivacaftor or lumacaftor-ivacaftor. At enrollment, pre-modulator sweat chloride was measured and historic results recorded. Post-modulator sweat chloride was measured at 1, 3 and 6 months. For this analysis, differences between historic and pre-modulator sweat chloride were estimated. CFTR modulator-induced sweat chloride mean changes were compared using historic and pre-modulator sweat chloride., Results: Paired historic and pre-modulator sweat chloride (n=406 participants) revealed a non-significant mean change of -1.0 mmol/L (95% CI: -2.71, 0.66) over an average of 17.2 years. Calculating sweat response to ivacaftor or lumacaftor-ivacaftor using historic or pre-modulator values resulted in similar estimates of modulator response. Based on these results, the CHEC-SC study was designed with a single, post-modulator sweat chloride measurement., Conclusions: Historic sweat chloride values provide a reliable estimate of pre-modulator sweat chloride for people starting on modulator therapy. The CHEC-SC study anticipates capturing approximately 5,000 sweat chloride values, providing an unprecedented understanding of sweat chloride across the CF population in the era of CFTR modulators., Competing Interests: Declaration of Competing Interest ETZ, NMH, DRV, SMR, MWK: grants or consulting CFF; DRV consults for aMoon, Arrevus, Eloxx, Enbiotix, Felix, Ionis, Matinas, Merck, Polyphor, Respirion, Savara; SMR consults for Vertex; MWK consults for Anthera, AzurRx, Celtaxsys, Chiesi, Ionis, Kala, Laurent, Merck, Paranta, pH Pharma, Santhera, Vertex; JPC, KOD and MS: none., (Copyright © 2021. Published by Elsevier B.V.)

Background: Riociguat is a first-in-class soluble guanylate cyclase stimulator for which preclinical data suggested improvements in cystic fibrosis transmembrane conductance regulator (CFTR) function., Methods: This international, multicenter, two-part, Phase II study of riociguat enrolled adults with cystic fibrosis (CF) homozygous for Phe508del CFTR. Part 1 was a 28-day, randomized, double-blind, placebo-controlled study in participants not receiving CFTR modulator therapy. Twenty-one participants were randomized 1:2 to placebo or oral riociguat (0.5 mg three times daily [tid] for 14 days, increased to 1.0 mg tid for the subsequent 14 days). The primary and secondary efficacy endpoints were change in sweat chloride concentration and percent predicted forced expiratory volume in 1 second (ppFEV 1 ), respectively, from baseline to Day 14 and Day 28 with riociguat compared with placebo., Results: Riociguat did not alter CFTR activity (change in sweat chloride) or lung function (change in ppFEV 1 ) at doses up to 1.0 mg tid after 28 days. The most common drug-related adverse event (AE) was headache occurring in three participants (21%); serious AEs occurred in one participant receiving riociguat (7%) and one participant receiving placebo (14%). This safety profile was consistent with the underlying disease and the known safety of riociguat for its approved indications., Conclusions: The Rio-CF study was terminated due to lack of efficacy and the changing landscape of CF therapeutic development. The current study⁠, within its limits of a small sample size, did not provide evidence that riociguat could be a valid treatment option for CF., Clinical Trial Registration Number: NCT02170025., Competing Interests: Declaration of Competing Interest N. Derichs received a speaker honorarium from Vertex Pharmaceuticals, Inc. for participation in a symposium, and served as a consultant for Vertex Pharmaceuticals, Inc. at educational activities and advisory boards. J.L. Taylor-Cousar reports grants paid to her institution from the Cystic Fibrosis Foundation; grants paid to her institution and consulting and speaking fees from Vertex Pharmaceuticals, Inc.; grants paid to her institution from Bayer; grants, consulting, and speaking fees from Celtaxys; grants paid to her institution and consulting fees from Proteostasis Therapeutics, Inc.; consulting fees from Santhera, 4DMT, AbbVie, and Polarean; and grants paid to her institution from Eloxx Pharmaceuticals. J.C. Davies reports grants from the CF Trust and other funding from Algipharma AS, Bayer AG, Boehringer Ingelheim Pharma GmbH & Co. KG, Galapagos NV, ImevaX GmbH, Nivalis Therapeutics, Inc., ProQR Therapeutics III B.V., Proteostasis Therapeutics, Inc., Raptor Pharmaceuticals, Inc., Vertex Pharmaceuticals, Inc., Enterprise, Novartis, Pulmocide, Flatley, Nivalis Therapeutics, Inc., and Teva. I. Fajac received speaker honoraria from Vertex Pharmaceuticals, Inc. for participation in symposia and served as a consultant for Novartis, Proteostasis Therapeutics, Inc., and Vertex Pharmaceuticals, Inc. E. Tullis reports grants paid to her institution from Vertex Pharmaceuticals, Inc., Proteostasis Therapeutics, Bayer AG, Boehringer Ingelheim, AbbVie, Celtaxis, Corbus, and Spyryx, and consultancy fees and honoraria from Vertex Pharmaceuticals, Proteostasis Therapeutics, Astra Zeneca and Horizon. D. Nazareth has nothing to disclose. D.G. Downey reports grants from Vertex Pharmaceuticals, Inc., Proteostasis Therapeutics, Inc., Gilead, and Chiesi; and honoraria or speaker fees from Vertex Pharmaceuticals, Inc., Proteostasis Therapeutics, Inc., and Chiesi. D. Rosenbluth has nothing to disclose. A. Malfroot has nothing to disclose. C. Saunders has nothing to disclose. R. Jensen has nothing to disclose. G.M. Solomon reports work on advisory boards for Bayer and Electromed. F. Vermeulen has nothing to disclose. A. Kaiser is an employee of Bayer AG. S. Willmann is an employee of Bayer AG. S. Saleh is an employee of Bayer AG. K. Droebner is an employee of Bayer AG. P. Sandner is an employee of Bayer AG. C.E. Bear has nothing to disclose. A. Hoffmann is an employee of Bayer AG. F. Ratjen reports other consultancy fees from Vertex Pharmaceuticals, Inc., Bayer, Talecris, CSL Behring, Roche, and Gilead; grants and consultancy from Novartis; and developed speaker bureau for Genentech outside the submitted work. S.M. Rowe reports grants and consulting fees from Arrowhead, Bayer, Celtaxsys, Galapagos/AbbVie, Novartis, Renovion, Synedgen/Synspira, andVertex Pharmaceuticals Inc.; consulting fees from Arcturus, and Cysteic Medicines; and grants from AstraZeneca, Eloxx, N30 Pharmaceuticals, PTC Therapeutics, Translate Bio, and Proteostasis Therapeutics, Inc., (Copyright © 2021. Published by Elsevier B.V.)

Background: Cystic fibrosis (CF) is characterized by neutrophilic inflammation in the airways. Leukotriene B4 (LTB 4 ) is a neutrophil chemoattractant and has been implicated in CF pathogenesis. Acebilustat, a novel, synthetic, small-molecule leukotriene A4 hydrolase inhibitor, reduces LTB 4 production. We report findings from a randomized placebo-controlled trial of acebilustat in adult subjects with mild-to-moderate lung disease., Methods: Subjects were randomized (1:1:1) to once-daily acebilustat 50 mg, 100 mg or placebo for 48 weeks, concomitantly with their current therapeutic regimen. Subjects were stratified by use of concomitant CF transmembrane conductance regulator (CFTR) modulators, baseline percent predicted forced expiratory volume in 1 second (ppFEV 1 ) 50-75 and >75, and number of pulmonary exacerbations in the past year (1 or >1). Primary endpoints were the change from baseline in ppFEV 1 and safety. Secondary endpoints included the rate of pulmonary exacerbations., Results: Overall, 199 subjects were randomized and dosed (acebilustat 50 mg, n=67; acebilustat 100 mg, n=66; placebo, n=66). Baseline demographics and disease profile were well balanced among treatment groups. Acebilustat had no statistically significant effect on the primary endpoint of change in ppFEV 1 at week 48 or the secondary endpoint pulmonary exacerbations. There was a trend towards reduced pulmonary exacerbations in subjects receiving acebilustat in pre-specified populations with ppFEV 1 >75 (35% rate reduction) and those on concomitant CFTR modulator therapy (20% rate reduction). Acebilustat was well tolerated., Conclusions: Acebilustat did not improve lung function. A trend towards reduced pulmonary exacerbations in subjects with an earlier stage of lung disease suggests a potential effect in this population., Competing Interests: Declaration of Competing Interest Dr. Aaron has nothing to disclose. Dr. Ahuja reports personal fees from Celtaxsys, Inc., during the conduct of the study; In addition, Dr. Ahuja has a patent PCT/US19/034810 pending, and a patent US16/427,571 pending. Dr. Daines has nothing to disclose. Dr. Downey reports and Honoraria from Vertex, Proteostasis and Chiesi. Dr. Elborn reports other from Celtaxsys, during the conduct of the study; grants and other from Corbus, grants from Novartis, grants from polyphor, outside the submitted work. Dr. Fajac reports grants from Celtaxsys, during the conduct of the study; grants and personal fees from Boehringer Ingelheim, grants and personal fees from Proteostasis Therapeutics, grants and personal fees from Vertex Pharmaceuticals, outside the submitted work. Mr. Grosswald reports personal fees from Celtaxsys, Inc., during the conduct of the study; In addition, Dr. Grosswald has a patent PCT/US19/034810 pending, and a patent US16/427,571 pending. Dr. Horsley reports other from Celtaxys pharmaceuticals, during the conduct of the study; grants from NIHR, grants from CF Trust, grants from CF Foundation, personal fees from Vertex pharmaceuticals, personal fees from Mylan, outside the submitted work. Dr. Konstan reports personal fees from Celtaxsys, during the conduct of the study; grants and personal fees from Vertex Pharmaceuticals, personal fees from Chiesi, personal fees from Ionis Pharmaceuticals, grants and personal fees from Laurent Pharmaceuticals, grants and personal fees from Anthera, personal fees from Merck, personal fees from Paranta Biosciences, personal fees from Santhera, personal fees from pH Pharma, grants and personal fees from Cystic Fibrosis Foundation, grants from National Institutes of Health, grants and personal fees from AzurRx, personal fees from Kala Pharmaceuticals, outside the submitted work. John Mershon has nothing to disclose. Dr. Rowe reports grants from Celtaxsys, during the conduct of the study; grants and personal fees from Novartis, grants and personal fees from Bayer, grants from Translate Bio, non-financial support from Proteostasis, grants, personal fees and non-financial support from Galapagos/Abbvie, grants, personal fees and other from Synedgen/Synspira, grants from Eloxx, grants from Celtaxsys, grants, personal fees, non-financial support and other from Vertex Pharmaceuticals Inc, personal fees from Renovion, grants and personal fees from Arrowhead, grants and other from Ionis, grants from Astra Zenica, outside the submitted work. Dr. Springman reports personal fees from Celtaxsys, Inc., during the conduct of the study; In addition, Dr. Springman has a patent PCT/US19/034810 pending, and a patent US16/427,571 pending. Dr. Sutharsan reports personal fees personal Proteostasis Therapeutics, personal fees from Novartis Pharma GmbH, personal fees from Vertex Pharmaceuticals Incorporated, personal fees from Teva GmbH, personal fees from Chiesi GmbH, outside the submitted work; . SS has served as an investigator in clinical trials for Galapagos NV, Proteostasis, Celtaxsys, Flatley Discovery Lab, Novartis and Vertex. Dr. Taylor-Cousar reports grants and personal fees from Celtaxys, during the conduct of the study; grants and personal fees from Gilead, grants from N30, grants and personal fees from Vertex, grants and personal fees from Proteostasis, grants from Bayer, personal fees from Novartis, personal fees from Genentech, personal fees from Protalix, personal fees from Santhera, personal fees from 4DMT, personal fees from Polarean Imaging, personal fees from Insmed, personal fees from Abbvie, outside the submitted work; and Service on the CF TDN Clinical Research Executive CommitteeÐervice as the Chair of the ATS Clinical Problems Assembly Program Committee. Dr. Uluer has served in an advisory capacity with Vertex and Eloxx but these relationships are in no way associated with the work submitted in this manuscript, (Crown Copyright © 2021. Published by Elsevier B.V. All rights reserved.)

The objective of this observational study was to compare 4 cow-level algorithms to predict cow-level intramammary infection (IMI) status (culture and MALDI-TOF) in late-lactation US dairy cows using standard measures of test performance. Secondary objectives were to estimate the likely effect of each algorithm, if used to guide selective dry cow therapy (SDCT), on dry cow antibiotic use in US dairy herds, and to investigate the importance of including clinical mastitis criteria in algorithm-guided SDCT. Cows (n = 1,594) from 56 US dairy herds were recruited as part of a previously published cross-sectional study of bedding management and IMI in late-lactation cows. Each herd was visited twice for sampling. At each farm visit, aseptic quarter-milk samples were collected from 20 cows approaching dry-off (>180 d pregnant), which were cultured using standard bacteriological methods and MALDI-TOF for identification of isolates. Quarter-level culture results were used to establish cow-level IMI status, which was considered the reference test in this study. Clinical mastitis records and Dairy Herd Improvement Association test-day somatic cell count data were extracted from herd records and used to perform cow-level risk assessments (low vs. high risk) using 4 algorithms that have been proposed for SDCT in New Zealand, the Netherlands, United Kingdom, and the United States. Agreement between aerobic culture (reference test; IMI vs. no-IMI) and algorithm status (high vs. low risk) was described using Cohen's kappa, test sensitivity, specificity, negative predictive value, and positive predictive value. The proportion of cows classified as high risk among the 4 algorithms ranged from 0.31 to 0.63, indicating that these approaches to SDCT could reduce antibiotic use at dry-off by 37 to 69% in the average US herd. All algorithms had poor agreement with IMI status, with kappa values ranging from 0.05 to 0.13. Sensitivity varied by pathogen, with higher values observed when detecting IMI caused by Streptococcus uberis, Streptococcus dysgalactiae, Staphylococcus aureus, and Lactococcus lactis. Negative predictive values were high for major pathogens among all algorithms (≥0.87), which may explain why algorithm-guided SDCT programs have been successfully implemented in field trials, despite poor agreement with overall IMI status. Removal of clinical mastitis criteria for each algorithm had little effect on the algorithm classification of cows, indicating that algorithms based on SCC alone may have similar performance to those based on SCC and clinical mastitis criteria. We recommend that producers implementing algorithm-guided SDCT use algorithm criteria that matches their relative aspirations for reducing antibiotic use (high specificity, positive predictive value) or minimizing untreated IMI at dry-off (high sensitivity, negative predictive value)., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)