Cystic Fibrosis
Carrier Screening Programs for Cystic Fibrosis, Fragile X Syndrome, Hemoglobinopathies and Thalassemia, and Spinal Muscular Atrophy: A Health Technology Assessment
Ont Health Technol Assess Ser. 2023 Aug 10;23(4):1-398. eCollection 2023.
ABSTRACT
BACKGROUND: We conducted a health technology assessment to evaluate the safety, effectiveness, and cost-effectiveness of carrier screening programs for cystic fibrosis (CF), fragile X syndrome (FXS), hemoglobinopathies and thalassemia, and spinal muscular atrophy (SMA) in people who are considering a pregnancy or who are pregnant. We also evaluated the budget impact of publicly funding carrier screening programs, and patient preferences and values.
METHODS: We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using the Cochrane Risk of Bias tool and the Risk of Bias Assessment tool for Non-randomized Studies (RoBANS), and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted cost-effectiveness analyses comparing preconception or prenatal carrier screening programs to no screening. We considered four carrier screening strategies: 1) universal screening with standard panels; 2) universal screening with a hypothetical expanded panel; 3) risk-based screening with standard panels; and 4) risk-based screening with a hypothetical expanded panel. We also estimated the 5-year budget impact of publicly funding preconception or prenatal carrier screening programs for the given conditions in Ontario. To contextualize the potential value of carrier screening, we spoke with 22 people who had sought out carrier screening.
RESULTS: We included 107 studies in the clinical evidence review. Carrier screening for CF, hemoglobinopathies and thalassemia, FXS, and SMA likely results in the identification of couples with an increased chance of having an affected pregnancy (GRADE: Moderate). Screening likely impacts reproductive decision-making (GRADE: Moderate) and may result in lower anxiety among pregnant people, although the evidence is uncertain (GRADE: Very low).We included 21 studies in the economic evidence review, but none of the study findings were directly applicable to the Ontario context. Our cost-effectiveness analyses showed that in the short term, preconception or prenatal carrier screening programs identified more at-risk pregnancies (i.e., couples that tested positive) and provided more reproductive choice options compared with no screening, but were associated with higher costs. While all screening strategies had similar values for health outcomes, when comparing all strategies together, universal screening with standard panels was the most cost-effective strategy for both preconception and prenatal periods. The incremental cost-effectiveness ratios (ICERs) of universal screening with standard panels compared with no screening in the preconception period were $29,106 per additional at-risk pregnancy detected and $367,731 per affected birth averted; the corresponding ICERs in the prenatal period were about $29,759 per additional at-risk pregnancy detected and $431,807 per affected birth averted.We estimated that publicly funding a universal carrier screening program in the preconception period over the next 5 years would require between $208 million and $491 million. Publicly funding a risk-based screening program in the preconception period over the next 5 years would require between $1.3 million and $2.7 million. Publicly funding a universal carrier screening program in the prenatal period over the next 5 years would require between $128 million and $305 million. Publicly funding a risk-based screening program in the prenatal period over the next 5 years would require between $0.8 million and $1.7 million. Accounting for treatment costs of the screened health conditions resulted in a decrease in the budget impact of universally provided carrier screening programs or cost savings for risk-based programs.Participants value the perceived potential positive impact of carrier screening programs such as medical benefits from early detection and treatment, information for reproductive decision-making, and the social benefit of awareness and preparation. There was a strong preference expressed for thorough, timely, unbiased information to allow for informed reproductive decision-making.
CONCLUSIONS: Carrier screening for CF, FXS, hemoglobinopathies and thalassemia, and SMA is effective at identifying at-risk couples, and test results may impact preconception and reproductive decision-making.The cost-effectiveness and budget impact of carrier screening programs are uncertain for Ontario. Over the short term, carrier screening programs are associated with higher costs, and also higher chances of detecting at-risk pregnancies compared with no screening. The 5-year budget impact of publicly funding universal carrier screening programs is larger than that of risk-based programs. However, accounting for treatment costs of the screened health conditions results in a decrease in the total additional costs for universal carrier screening programs or in cost savings for risk-based programs.The people we spoke with who had sought out carrier screening valued the potential medical benefits of early detection and treatment, particularly the support and preparation for having a child with a potential genetic condition.
PMID:37637488 | PMC:PMC10453298
A rare case of meconium peritonitis in a neonate: a rare clinical image
Pan Afr Med J. 2023 May 29;45:65. doi: 10.11604/pamj.2023.45.65.39001. eCollection 2023.
NO ABSTRACT
PMID:37637388 | PMC:PMC10460095 | DOI:10.11604/pamj.2023.45.65.39001
Editorial: Insights in adrenal endocrinology: 2023
Front Endocrinol (Lausanne). 2023 Aug 11;14:1263894. doi: 10.3389/fendo.2023.1263894. eCollection 2023.
NO ABSTRACT
PMID:37635969 | PMC:PMC10455912 | DOI:10.3389/fendo.2023.1263894
Editorial: New insights into caring for pediatric patients with cystic fibrosis
Front Pediatr. 2023 Aug 9;11:1243496. doi: 10.3389/fped.2023.1243496. eCollection 2023.
NO ABSTRACT
PMID:37635799 | PMC:PMC10450029 | DOI:10.3389/fped.2023.1243496
Extracellular vesicles from BALF of pediatric cystic fibrosis and asthma patients increase epithelial sodium channel activity in small airway epithelial cells
Biochim Biophys Acta Biomembr. 2023 Aug 25:184219. doi: 10.1016/j.bbamem.2023.184219. Online ahead of print.
ABSTRACT
Extracellular Vesicles (EVs) are nanosized vesicles derived from all cell types. EV cargo allows for intercellular communication, intracellular signaling, and regulation of proteins in recipient cells. We tested the hypothesis that EVs isolated from the bronchoalveolar-lavage fluid (BALF) of pediatric cystic fibrosis (CF) or pediatric asthma patients increase epithelial sodium channel (ENaC) activity in normal human small airway epithelial cells (SAECs) and the mechanism involves specific EV lipids. We characterized EVs from BALF of pediatric CF and pediatric asthma patients by nanoparticle tracking analysis, transmission electron microscopy, and Western blotting. The CF and asthma pediatric groups were similar in BALF electrolytes concentration and cell count, except for neutrophils, which were higher in the CF group. Lipidomic analyses for each group of EVs were performed using targeted mass spectrometry. Phosphatidylethanolamine, sphingomyelins, and triacylglycerol were enriched in both groups, but phosphatidylcholine and phosphatidylinositol concentrations were greater in the CF group compared to the asthma group, and the opposite trend was found for phosphatidylserine. Endogenous ENaC activity, measured by the single-channel patch-clamp technique, increased in normal human SAECs after challenging SAEC with EVs from either the CF or asthma groups compared to control EVs. In conclusion, EVs isolated from BALF of pediatric patients with CF or asthma have unique lipid profiles. Despite the differences, both types of EVs increase ENaC activity in normal human SAECs compared to control EVs isolated from the conditioned media of these cells.
PMID:37634857 | DOI:10.1016/j.bbamem.2023.184219
Pancreatic duct organoid swelling is chloride-dependent
J Cyst Fibros. 2023 Aug 24:S1569-1993(23)00872-X. doi: 10.1016/j.jcf.2023.08.003. Online ahead of print.
ABSTRACT
Pancreatic secretions become viscous and acidic in Cystic fibrosis (CF), highlighting the role of CFTR in pancreatic fluid and bicarbonate secretion. Forskolin-induced swelling (FIS) assay developed in intestinal organoids measures residual CFTR function. It is not known whether FIS reflects bicarbonate secretion in pancreas, an organ that secretes near-isotonic NaHCO3 levels. To investigate this, we generated pancreatic duct organoids from CF and non-CF pigs. Epithelial and ductal origin was confirmed with epithelial markers, ion transporters and lack of acinar, islet cell markers. CF organoids were small with no identifiable lumen; CFTR was expressed only in non-CF organoids. Utilizing FIS, organoid size increased only in response to chloride, not bicarbonate. This report highlights pancreatic duct organoids isolated for the first time from CF pigs and evidence for chloride and not bicarbonate driving pancreatic organoid swelling. These organoids would be useful to test chloride permeability of CFTR mutations that cause CF pancreatic disease.
PMID:37633792 | DOI:10.1016/j.jcf.2023.08.003
Relationship between Aspergillus and asthma
Allergol Int. 2023 Aug 24:S1323-8930(23)00080-1. doi: 10.1016/j.alit.2023.08.004. Online ahead of print.
ABSTRACT
Fungal sensitization is highly prevalent in severe asthma. The relationship between fungus and asthma, especially Aspergillus fumigatus, has been the subject of extensive research. The ubiquitous presence of A. fumigatus, its thermotolerant nature, the respirable size of its conidia, and its ability to produce potent allergens are pivotal in worsening asthma control. Due to the diverse clinical manifestations of fungal asthma and the lack of specific biomarkers, its diagnosis remains intricate. Diagnosing fungal asthma requires carefully assessing the patient's clinical history, immunological tests, and imaging. Depending on the severity, patients with fungal asthma require personalized treatment plans, including inhaled corticosteroids and bronchodilators, and antifungal therapy. This review provides a comprehensive overview of the association between Aspergillus and asthma by reviewing the relevant literature and highlighting key findings. We discuss the diagnosis of various entities included in fungal asthma. We also debate whether newer definitions, including allergic fungal airway disease, offer any additional advantages over the existing ones. Finally, we provide the current treatment options for the individual entities, including A. fumigatus-associated asthma, severe asthma with fungal sensitization, and allergic bronchopulmonary mycoses.
PMID:37633774 | DOI:10.1016/j.alit.2023.08.004
An elevated prevalence of hereditary alpha-tryptasemia in all mastocytosis subtypes: pathophysiological implications
J Allergy Clin Immunol. 2023 Aug 24:S0091-6749(23)01068-0. doi: 10.1016/j.jaci.2023.08.015. Online ahead of print.
ABSTRACT
BACKGROUND: Mastocytosis and monoclonal mast cell (MC) activation syndrome (MMAS) are heterogeneous conditions characterized by the accumulation of atypical MCs. Despite the recurrent involvement of KIT mutations, the pathophysiological origin of mastocytosis and MMAS is unclear. Although hereditary α-tryptasemia (HαT, related to TPSAB1 gene duplication) is abnormally frequent in these diseases, it is not known whether the association is coincidental or causal.
OBJECTIVE: To evaluate the prevalence of HαT in all mastocytosis subtypes and MMAS and assess the pathophysiological association with HαT.
METHODS: Clinical data, laboratory data, KIT mutations, TPSAB1 duplication (assessed with droplet digital PCR) and the prevalence of HαT were retrospectively recorded for all patients with mastocytosis and MMAS registered in the French national referral center database and compared with a control cohort. To increase the power of our analysis for advanced systemic mastocytosis (advSM), we pooled our cohort with literature cases.
RESULTS: We included 583 patients (27 with MMAS and 556 with mastocytosis). The prevalence of H⍺T in mastocytosis was 12.6%, significantly higher than in the general population (5.7%, p=0.002) and lower than in MMAS (33.3%, p=0.02). H⍺T+ patients were more likely to have anaphylactic reactions and less likely to have cutaneous lesions than H⍺T- patients (43.0% vs 24.4%, p=0.006; 57.7% vs. 75.6%, respectively, p=0.006). In the pooled analysis, the prevalence of H⍺T was higher in advSM (11.5%) than in control cohorts (5.2%, p=0.01).
CONCLUSION: Here we confirm the increase incidence of anaphylaxis in H⍺T+ mastocytosis patients. The increased prevalence of H⍺T in all subtypes of systemic mastocytosis (including advSM) is suggestive of pathophysiological involvement.
PMID:37633651 | DOI:10.1016/j.jaci.2023.08.015
The development and characterization of in vivo-like three-dimensional models of bronchial epithelial cell lines
Eur J Pharm Sci. 2023 Aug 24:106567. doi: 10.1016/j.ejps.2023.106567. Online ahead of print.
ABSTRACT
In vitro models of differentiated respiratory epithelium that allow high-throughput screening are an important tool to explore new therapeutics for chronic respiratory diseases. In the present study, we developed in vivo-like three-dimensional (3-D) models of bronchial epithelial cell lines that are commonly used to study chronic lung disease (16HBE14o-, CFBE41o- and CFBE41o- 6.2 WT-CFTR). To this end, cells were cultured on porous microcarrier beads in the rotating wall vessel (RWV) bioreactor, an optimized suspension culture method that allows higher throughput experimentation than other physiologically relevant models. Cell differentiation was compared to conventional two-dimensional (2-D) monolayer cultures and to the current gold standard in the respiratory field, i.e. air-liquid interface (ALI) cultures. Cellular differentiation was assessed in the three model systems by evaluating the expression and localization of markers that reflect the formation of tight junctions (zonula occludens 1), cell polarity (intercellular adhesion molecule 1 at the apical side and collagen IV expression at the basal cell side), multicellular complexity (acetylated α-tubulin for ciliated cells, CC10 for club cells, keratin-5 for basal cells) and mucus production (MUC5AC) through immunostaining and confocal laser scanning microscopy. Results were validated using Western Blot analysis. We found that tight junctions were expressed in 2-D monolayers, ALI cultures and 3-D models for all three cell lines. All tested bronchial epithelial cell lines showed polarization in ALI and 3-D cultures, but not in 2-D monolayers. Mucus secreting goblet-like cells were present in ALI and 3-D cultures of CFBE41o- and CFBE41o- 6.2 WT-CFTR cells, but not in 16HBE14o- cells. For all cell lines, there were no ciliated cells, basal cells, or club cells found in any of the model systems. In conclusion, we developed RWV-derived 3-D models of commonly used bronchial epithelial cell lines and showed that these models are a valuable alternative to ALI cultures, as they recapitulate similar key aspects of the in vivo parental tissue.
PMID:37633341 | DOI:10.1016/j.ejps.2023.106567
Compounding <em>Achromobacter</em> Phages for Therapeutic Applications
Viruses. 2023 Jul 30;15(8):1665. doi: 10.3390/v15081665.
ABSTRACT
Achromobacter species colonization of Cystic Fibrosis respiratory airways is an increasing concern. Two adult patients with Cystic Fibrosis colonized by Achromobacter xylosoxidans CF418 or Achromobacter ruhlandii CF116 experienced fatal exacerbations. Achromobacter spp. are naturally resistant to several antibiotics. Therefore, phages could be valuable as therapeutics for the control of Achromobacter. In this study, thirteen lytic phages were isolated and characterized at the morphological and genomic levels for potential future use in phage therapy. They are presented here as the Achromobacter Kumeyaay phage collection. Six distinct Achromobacter phage genome clusters were identified based on a comprehensive phylogenetic analysis of the Kumeyaay collection as well as the publicly available Achromobacter phages. The infectivity of all phages in the Kumeyaay collection was tested in 23 Achromobacter clinical isolates; 78% of these isolates were lysed by at least one phage. A cryptic prophage was induced in Achromobacter xylosoxidans CF418 when infected with some of the lytic phages. This prophage genome was characterized and is presented as Achromobacter phage CF418-P1. Prophage induction during lytic phage preparation for therapy interventions require further exploration. Large-scale production of phages and removal of endotoxins using an octanol-based procedure resulted in a phage concentrate of 1 × 109 plaque-forming units per milliliter with an endotoxin concentration of 65 endotoxin units per milliliter, which is below the Food and Drugs Administration recommended maximum threshold for human administration. This study provides a comprehensive framework for the isolation, bioinformatic characterization, and safe production of phages to kill Achromobacter spp. in order to potentially manage Cystic Fibrosis (CF) pulmonary infections.
PMID:37632008 | DOI:10.3390/v15081665
Clinical and Experimental Determination of Protection Afforded by BCG Vaccination against Infection with Non-Tuberculous Mycobacteria: A Role in Cystic Fibrosis?
Vaccines (Basel). 2023 Aug 1;11(8):1313. doi: 10.3390/vaccines11081313.
ABSTRACT
Mycobacterium abscessus is a nontuberculous mycobacterium (NTM) of particular concern in individuals with obstructive lung diseases such as cystic fibrosis (CF). Treatment requires multiple drugs and is characterised by high rates of relapse; thus, new strategies to limit infection are urgently required. This study sought to determine how Bacille Calmette-Guérin (BCG) vaccination may impact NTM infection, using a murine model of Mycobacterium abscessus infection and observational data from a non-BCG vaccinated CF cohort in Sydney, Australia and a BCG-vaccinated CF cohort in Cape Town, South Africa. In mice, BCG vaccination induced multifunctional antigen-specific CD4+ T cells circulating in the blood and was protective against dissemination of bacteria to the spleen. Prior infection with M. abscessus afforded the highest level of protection against M. abscessus challenge in the lung, and immunity was characterised by a greater frequency of pulmonary cytokine-secreting CD4+ T cells compared to BCG vaccination. In the clinical CF cohorts, the overall rates of NTM sampling during a three-year period were equivalent; however, rates of NTM colonisation were significantly lower in the BCG-vaccinated (Cape Town) cohort, which was most apparent for M. abscessus. This study provides evidence that routine BCG vaccination may reduce M. abscessus colonisation in individuals with CF, which correlates with the ability of BCG to induce multifunctional CD4+ T cells recognising M. abscessus in a murine model. Further research is needed to determine the optimal strategies for limiting NTM infections in individuals with CF.
PMID:37631881 | DOI:10.3390/vaccines11081313
Advancing Treatment Strategies: A Comprehensive Review of Drug Delivery Innovations for Chronic Inflammatory Respiratory Diseases
Pharmaceutics. 2023 Aug 17;15(8):2151. doi: 10.3390/pharmaceutics15082151.
ABSTRACT
Chronic inflammatory respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, present ongoing challenges in terms of effective treatment and management. These diseases are characterized by persistent inflammation in the airways, leading to structural changes and compromised lung function. There are several treatments available for them, such as bronchodilators, immunomodulators, and oxygen therapy. However, there are still some shortcomings in the effectiveness and side effects of drugs. To achieve optimal therapeutic outcomes while minimizing systemic side effects, targeted therapies and precise drug delivery systems are crucial to the management of these diseases. This comprehensive review focuses on the role of drug delivery systems in chronic inflammatory respiratory diseases, particularly nanoparticle-based drug delivery systems, inhaled corticosteroids (ICSs), novel biologicals, gene therapy, and personalized medicine. By examining the latest advancements and strategies in these areas, we aim to provide a thorough understanding of the current landscape and future prospects for improving treatment outcomes in these challenging conditions.
PMID:37631365 | DOI:10.3390/pharmaceutics15082151
The Interplay between Microbiota and Human Complex Traits
Microorganisms. 2023 Aug 11;11(8):2066. doi: 10.3390/microorganisms11082066.
ABSTRACT
Microorganisms have been one of the most influential drivers propelling some of the greatest environmental and evolutionary changes in the landscape and biology of the entire planet [...].
PMID:37630626 | DOI:10.3390/microorganisms11082066
Infection, Allergy, and Inflammation: The Role of <em>Aspergillus fumigatus</em> in Cystic Fibrosis
Microorganisms. 2023 Aug 5;11(8):2013. doi: 10.3390/microorganisms11082013.
ABSTRACT
Aspergillus fumigatus (Af) is a mold frequently detected in airway samples from people with cystic fibrosis (pwCF). Abnormal airway mucus may allow Af to germinate, resulting in airway infection or an allergic response. While Af is known to increase morbidity in pwCF, individual responses and the degree of impact on lung disease vary. Improved approaches to diagnosis, treatment, and prevention of Af, particularly the persistent Af infection, are needed. This update highlights our current understanding of Af pathophysiology in the CF airway, the effects of Af on pwCF, and areas of research needed to improve clinical outcomes.
PMID:37630573 | DOI:10.3390/microorganisms11082013
Diagnostic and Communication Challenges in Cystic Fibrosis Newborn Screening
Life (Basel). 2023 Jul 28;13(8):1646. doi: 10.3390/life13081646.
ABSTRACT
As of December 2009, cystic fibrosis (CF) newborn screening (NBS) is performed in all 50 US states and the District of Columbia. Widespread implementation of CF newborn screening (CFNBS) in the US and internationally has brought about new and varied challenges. Immunoreactive trypsinogen (IRT) remains the first, albeit imperfect, biomarker used universally in the screening process. Advances in genetic testing have provided an opportunity for newborn screening programs to add CFTR sequencing tiers to their algorithms. This in turn will enable earlier identification of babies with CF and improve longer-term outcomes through prompt treatment and intervention. CFTR sequencing has led to the ability to identify infants with CF from diverse ethnic and racial backgrounds more equitably while also identifying an increasing proportion of infants with inconclusive diagnoses. Using the evolution of the New York State CF newborn screening program as a guide, this review outlines the basic steps in a universal CF newborn screening program, considers how to reduce bias, highlights challenges, offers guidance to address these challenges and provides recommendations for future consideration.
PMID:37629501 | DOI:10.3390/life13081646
Addressing Symptom Burden and Palliative Care Needs in Cystic Fibrosis: A Narrative Review of the Literature
Life (Basel). 2023 Jul 25;13(8):1620. doi: 10.3390/life13081620.
ABSTRACT
Among people with cystic fibrosis (CF), illness burden is multifaceted, and symptoms may fluctuate in intensity across a lifespan. Caregivers of people with CF may also experience distressing symptoms. Recent developments in CF care, including the availability of highly effective modulator therapies (HEMTs) and new palliative care guidelines promoting palliative care screening may help alleviate symptoms. The objective of this review was to present a narrative view of the recent literature on symptom burden in CF, new screening approaches informed by the Cystic Fibrosis Foundation (CFF) palliative care guidelines, and early data from studies examining the impact of HEMTs on CF symptom burden. A review of the relevant literature was conducted using Google Scholar and PubMed. Included articles covered approaches to burden assessment in CF and other chronic illnesses, epidemiology of CF symptom burden, the impact of HEMTs on symptom burden, and the CFF palliative care guidelines. A primary palliative care model implementing the CFF guidelines was also described. Results of this review show that while recent developments in CF care have led to a reduction in physical symptoms, mental health symptoms remain prevalent. Ongoing screening and triage can ensure that physical symptoms, psychological symptoms, social needs, practical problems, and communication concerns are addressed by care teams.
PMID:37629478 | DOI:10.3390/life13081620
Parents' Knowledge of the Impact of Cystic Fibrosis on the Quality of Life of Children and Adolescents Suffering from This Disease as an Element of Patient Safety
J Clin Med. 2023 Aug 10;12(16):5214. doi: 10.3390/jcm12165214.
ABSTRACT
Parental perspective on the health, safety, and quality of life in children and adolescents with cystic fibrosis (CF).
AIM OF THE STUDY: Assessment of the impact of a chronic disease such as cystic fibrosis (CF) on the quality of life and safety of children and adolescents as perceived by parents/caretakers.
METHODS: The study was conducted at the Department of Lung Diseases of the Institute of Mother and Child, a branch of the Cystic Fibrosis Centre Children of Warsaw SZPZOZ in Dziekanów Leśny, the largest pediatric CF center in Poland, and in the Rodzinamuko group on Facebook. A total of 139 parents participated in the study. The study was conducted using the diagnostic survey method with the use of the Kid- & Kiddo-KINDLR questionnaire for examining the quality of life of children and adolescents and a demographic questionnaire.
RESULTS: The perception of cystic fibrosis (CF) as a chronic disease varies based on parental residence and professional status. The well-being of children and adolescents with CF is tied to their parents' employment, particularly regarding schooling. Social interactions are influenced by the level of parental education. The quality of life in children and adolescents with CF is age-dependent, with younger children exhibiting higher quality of life. This age-quality of life relationship extends to physical well-being, emotional well-being, and school-related aspects. Furthermore, the emotional dimension of quality of life is affected by the child's age at the time of diagnosis.
CONCLUSIONS: The Kid- & Kiddo-KINDLR QoL Questionnaire for children with cystic fibrosis is a good tool to measure parental knowledge. The study shows the need for the whole family to understand and be aware of the impact of CF on family life. Parents may be tired or may misunderstand or miscommunicate the medical team's instructions, which may affect both family life and patient safety. To ensure patient safety, parents should work with healthcare professionals at hospitals or clinics but also at home. They should also account for the family as a whole, not just for the problems of the child with CF.
PMID:37629256 | DOI:10.3390/jcm12165214
Elexacaftor Mediates the Rescue of F508del CFTR Functional Expression Interacting with MSD2
Int J Mol Sci. 2023 Aug 16;24(16):12838. doi: 10.3390/ijms241612838.
ABSTRACT
Cystic fibrosis (CF) is one of the most frequent lethal autosomal recessive diseases affecting the Caucasian population. It is caused by loss of function variants of the cystic fibrosis transmembrane conductance regulator (CFTR), a membrane protein located on the apical side of epithelial cells. The most prevalent CF-causing mutation, the deletion of phenylalanine at position 508 (F508del), is characterized by folding and trafficking defects, resulting in the decreased functional expression of the protein on the plasma membrane. Two classes of small-molecule modulators, termed potentiators and correctors, respectively, have been developed to rescue either the gating or the cellular processing of defective F508del CFTR. Kaftrio, a next-generation triple-combination drug, consisting of the potentiator ivacaftor (VX770) and the two correctors tezacaftor (VX661) and elexacaftor (VX445), has been demonstrated to be a life-changing therapeutic modality for the majority of people with CF worldwide. While the mechanism of action of VX770 and VX661 is almost known, the precise mechanism of action and binding site of VX445 have not been conclusively determined. We investigated the activity of VX445 on mutant F508del to identify the protein domains whose expression is mostly affected by this corrector and to disclose its mechanisms of action. Our biochemical analyses revealed that VX445 specifically improves the expression and the maturation of MSD2, heterologously expressed in HEK 293 cells, and confirmed that its effect on the functional expression of defective F508del CFTR is additive either with type I or type II CFTR correctors. We are confident that our study will help to make a step forward in the comprehension of the etiopathology of the CF disease, as well as to give new information for the development and testing of combinations of even more effective correctors able to target mutation-specific defects of the CFTR protein.
PMID:37629017 | DOI:10.3390/ijms241612838
CFTR Modulates Hypothalamic Neuron Excitability to Maintain Female Cycle
Int J Mol Sci. 2023 Aug 8;24(16):12572. doi: 10.3390/ijms241612572.
ABSTRACT
Cystic fibrosis transmembrane conductance regulator (CFTR), known as an epithelial Cl- channel, is increasingly noted to be expressed in the nervous system, although whether and how it plays a role in neuronal excitability is unclear. Given the association of CFTR with fertility, we tested here possible involvement of CFTR in regulating hypothalamic neuron excitability. Patch-clamp and Ca2+ imaging showed that pharmacological inhibition of CFTR evoked electrical pulses and Ca2+ spikes in primary rat hypothalamic neurons, which was dependent on extracellular Cl-. Hypothalamic neurons in brain-slice preparations from adult female mice with CFTR mutation (DF508) exhibited significantly reduced electrical pulses as compared to the wild-type controls. Removal of extracellular Cl- eliminated hypothalamic electrical pulses in the wild-type brain slices, which was reversible by subsequent addition of Cl-. In adult female mice, Ca2+ indicator (GCaMP6s)-based fiber-photometry showed that hypothalamic Ca2+ activities in vivo were enhanced at the proestrus/estrus phase as compared to the diestrus phase of the female cycle. Such estrus-associated hypothalamic activities were largely diminished in DF508 female mice, together with delayed puberty and disturbed female cycles. Therefore, these findings suggest a critical role of CFTR in modulating hypothalamic neuron excitability, which may account for the disturbed female cycles and reduced female fertility associated with CFTR mutations.
PMID:37628754 | DOI:10.3390/ijms241612572
Next-Generation Sequencing for Screening Analysis of Cystic Fibrosis: Spectrum and Novel Variants in a South-Central Italian Cohort
Genes (Basel). 2023 Aug 11;14(8):1608. doi: 10.3390/genes14081608.
ABSTRACT
The incidence of cystic fibrosis (CF) and the spectrum of cystic fibrosis transmembrane conductance regulator (CFTR) gene variants differ among geographic regions. Differences in CF carrier distribution are also reported among Italian regions. We described the spectrum of the CFTR variants observed in a large group of subjects belonging from central-southern Italy. We also provide a predictive evaluation of the novel variants identified. CFTR screening was performed in a south-central Italian cohort of 770 subjects. We adopted a next-generation sequencing (NGS) approach using the Devyser CFTR NGS kit on the Illumina MiSeq System coupled with Amplicon Suite data analysis. Bioinformatics evaluation of the impact of novel variants was described. Overall, the presence of at least one alternative allele in the CFTR gene was recorded for 23% of the subjects, with a carrier frequency of CF pathogenic variants of 1:12. The largest sub-group corresponded to the heterozygous carriers of a variant with a conflicting interpretation of pathogenicity. The common CFTR p.(Phe508del) pathogenic variants were identified in 37% of mutated subjects. Bioinformatics prediction supported a potential damaging effect for the three novel CFTR variants identified: p.(Leu1187Phe), p.(Pro22Thr), and c.744-3C > G. NGS applied to CF screening had the benefit of: effectively identifying asymptomatic carriers. It lies in a wide overview of CFTR variants and gives a comprehensive picture of the carrier prevalence. The identification of a high number of unclassified variants may represent a challenge whilst at the same time being of interest and relevance for clinicians.
PMID:37628659 | DOI:10.3390/genes14081608