scholarly journals A disorder clinically resembling cystic fibrosis caused by biallelic variants in the AGR2 gene

2021 ◽  
pp. jmedgenet-2021-108150
Author(s):  
Aida Bertoli-Avella ◽  
Ronja Hotakainen ◽  
Maryam Al Shehhi ◽  
Alice Urzi ◽  
Catarina Pareira ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Transcriptome Analysis ◽  
Drug Targets ◽  
Gene Deletion ◽  
Respiratory Infections ◽  
Autosomal Recessive Disorder ◽  
Chronic Diarrhoea ◽  
High Morbidity ◽  
Loss Of Function ◽  
Human Phenotype

PurposeWe sought to describe a disorder clinically mimicking cystic fibrosis (CF) and to elucidate its genetic cause.MethodsExome/genome sequencing and human phenotype ontology data of nearly 40 000 patients from our Bio/Databank were analysed. RNA sequencing of samples from the nasal mucosa from patients, carriers and controls followed by transcriptome analysis was performed.ResultsWe identified 13 patients from 9 families with a CF-like phenotype consisting of recurrent lower respiratory infections (13/13), failure to thrive (13/13) and chronic diarrhoea (8/13), with high morbidity and mortality. All patients had biallelic variants in AGR2, (1) two splice-site variants, (2) gene deletion and (3) three missense variants. We confirmed aberrant AGR2 transcripts caused by an intronic variant and complete absence of AGR2 transcripts caused by the large gene deletion, resulting in loss of function (LoF). Furthermore, transcriptome analysis identified significant downregulation of components of the mucociliary machinery (intraciliary transport, cilium organisation), as well as upregulation of immune processes.ConclusionWe describe a previously unrecognised autosomal recessive disorder caused by AGR2 variants. AGR2-related disease should be considered as a differential diagnosis in patients presenting a CF-like phenotype. This has implications for the molecular diagnosis and management of these patients. AGR2 LoF is likely the disease mechanism, with consequent impairment of the mucociliary defence machinery. Future studies should aim to establish a better understanding of the disease pathophysiology and to identify potential drug targets.

scholarly journals The Multifaceted Roles of MicroRNAs in Cystic Fibrosis

Diagnostics ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1102
Author(s):  
Fatima Domenica Elisa De Palma ◽  
Valeria Raia ◽  
Guido Kroemer ◽  
Maria Chiara Maiuri
Keyword(s):  
Cystic Fibrosis ◽  
Respiratory Infections ◽  
Current Knowledge ◽  
Pancreatic Insufficiency ◽  
Clinical Manifestations ◽  
Predictive Biomarkers ◽  
Loss Of Function ◽  
Gene Encoding ◽  
Multisystemic Disease

Cystic fibrosis (CF) is a lifelong disorder affecting 1 in 3500 live births worldwide. It is a monogenetic autosomal recessive disease caused by loss-of-function mutations in the gene encoding the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR), the impairment of which leads to ionic disequilibria in exocrine organs. This translates into a chronic multisystemic disease characterized by airway obstruction, respiratory infections, and pancreatic insufficiency as well as hepatobiliary and gastrointestinal dysfunction. Molecular characterization of the mutational heterogeneity of CFTR (affected by more than 2000 variants) improved the understanding and management of CF. However, these CFTR variants are linked to different clinical manifestations and phenotypes, and they affect response to treatments. Expanding evidence suggests that multisystemic disease affects CF pathology via impairing either CFTR or proteins regulated by CFTR. Thus, altering the expression of miRNAs in vivo could constitute an appealing strategy for developing new CF therapies. In this review, we will first describe the pathophysiology and clinical management of CF. Then, we will summarize the current knowledge on altered miRNAs in CF patients, with a focus on the miRNAs involved in the deregulation of CFTR and in the modulation of inflammation. We will highlight recent findings on the potential utility of measuring circulating miRNAs in CF as diagnostic, prognostic, and predictive biomarkers. Finally, we will provide an overview on potential miRNA-based therapeutic approaches.

Cystic fibrosis transmembrane conductance regulator modulators for cystic fibrosis: a new dawn?

2021 ◽  
pp. archdischild-2020-320680
Author(s):  
Claire Edmondson ◽  
Christopher William Course ◽  
Iolo Doull
Keyword(s):  
Cystic Fibrosis ◽  
Life Expectancy ◽  
Respiratory Infections ◽  
Autosomal Recessive Disorder ◽  
Societal Implications ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Potent Effect ◽  
Major Barrier ◽  
Cystic Fibrosis Transmembrane

Cystic fibrosis (CF) is the most common life-limiting inherited condition in Caucasians. It is a multisystem autosomal recessive disorder caused by variants in the gene for cystic fibrosis transmembrane conductance regulator (CFTR) protein, a cell-surface localised chloride channel that regulates absorption and secretion of salt and water across epithelia. Until recently, the treatment for CF was predicated on ameliorating and preventing the downstream symptoms of CFTR dysfunction, primarily recurrent respiratory infections and pancreatic exocrine failure. But a new class of therapy—the CFTR modulators, which treat the basic defect and decrease the complications of CF, leads to significantly improved pulmonary function, decreased respiratory infections and improved nutrition. The newest agent, a combination of elexacaftor, tezacaftor and ivacaftor, will be suitable for approximately 90% of all people with CF and is likely to decrease the morbidity and significantly increase the life expectancy for most people with CF. The major barrier to their widespread introduction has been their cost, with many countries unwilling or unable to fund them. Nevertheless, such is their therapeutic efficacy and their likely potent effect on life expectancy that their advent has wider societal implications for the care of children and adults with CF.

scholarly journals Innate Lung Defenses and Compromised Pseudomonas aeruginosa Clearance in the Malnourished Mouse Model of Respiratory Infections in Cystic Fibrosis

2000 ◽  
Vol 68 (4) ◽  
pp. 2142-2147 ◽  
Author(s):  
H. Yu ◽  
S. Z. Nasr ◽  
V. Deretic
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Knockout Mice ◽  
Respiratory Infections ◽  
Bacterial Colonization ◽  
Interleukin 10 ◽  
High Morbidity ◽  
Necrosis Factor Alpha ◽  
Pulmonary Clearance ◽  
Tnf Α

ABSTRACT Cystic fibrosis (CF) is characterized by dysfunction of the digestive and respiratory tracts resulting in generalized malnutrition and chronic respiratory infections. Chronic lung infections withPseudomonas aeruginosa, intense neutrophil-dominated airway inflammation, and progressive lung disease are the major cause of high morbidity and mortality in CF. Here we investigated the effects of malnutrition in CF on innate lung defenses, susceptibility to P. aeruginosa colonization, and associated inflammation, using aerosol models of acute and chronic infections in normal, malnourished, and transgenic mice. CFTRm1Unc−/− knockout mice displayed body weight variations and showed variable pulmonary clearance of P. aeruginosa. This variability was not detected in bitransgenicCFTRm1Unc−/− (FABP-hCFTR) mice in which the intestinal defect had been corrected. Diet-induced protein calorie malnutrition in C57BL/6J mice resulted in impaired pulmonary clearance of P. aeruginosa. Tumor necrosis factor alpha (TNF-α) and nitrite levels detected upon exposure to P. aeruginosaaerosols were lower in the lungs of the malnourished C57BL/6J mice relative than in lungs of mice fed a normal diet. The role of TNF-α and reactive nitrogen intermediates in P. aeruginosaclearance was tested in TNF-α and inducible nitric oxide synthase (iNOS) knockout mice. P. aeruginosa clearance was diminished in transgenic TNF-α- and iNOS-deficient mice. In contrast to the effects of TNF-α and iNOS, gamma interferon knockout mice retained a full capacity to eliminate P. aeruginosafrom the lung. Malnutrition also contributed to excessive inflammation in C57BL/6J mice upon chronic challenge with P. aeruginosa. The repeatedly infected malnourished host did not produce interleukin-10, a major anti-inflammatory cytokine absent or diminished in the bronchoalveolar fluids of CF patients. These results are consistent with a model in which defective CFTR in the intestinal tract leads to nutritional deficiency which in turn contributes to compromised innate lung defenses, bacterial colonization, and excessive inflammation in the CF respiratory tract.

scholarly journals Immunopathology of Airway Surface Liquid Dehydration Disease

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Brandon W. Lewis ◽  
Sonika Patial ◽  
Yogesh Saini
Keyword(s):  
Cystic Fibrosis ◽  
Mouse Model ◽  
Bacterial Infections ◽  
Structural Integrity ◽  
Respiratory Infections ◽  
Pulmonary Ventilation ◽  
High Morbidity ◽  
Airway Surface Liquid ◽  
Mucus Production ◽  
Surface Liquid

The primary purpose of pulmonary ventilation is to supply oxygen (O2) for sustained aerobic respiration in multicellular organisms. However, a plethora of abiotic insults and airborne pathogens present in the environment are occasionally introduced into the airspaces during inhalation, which could be detrimental to the structural integrity and functioning of the respiratory system. Multiple layers of host defense act in concert to eliminate unwanted constituents from the airspaces. In particular, the mucociliary escalator provides an effective mechanism for the continuous removal of inhaled insults including pathogens. Defects in the functioning of the mucociliary escalator compromise the mucociliary clearance (MCC) of inhaled pathogens, which favors microbial lung infection. Defective MCC is often associated with airway mucoobstruction, increased occurrence of respiratory infections, and progressive decrease in lung function in mucoobstructive lung diseases including cystic fibrosis (CF). In this disease, a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene results in dehydration of the airway surface liquid (ASL) layer. Several mice models of Cftr mutation have been developed; however, none of these models recapitulate human CF-like mucoobstructive lung disease. As an alternative, the Scnn1b transgenic (Scnn1b-Tg+) mouse model overexpressing a transgene encoding sodium channel nonvoltage-gated 1, beta subunit (Scnn1b) in airway club cells is available. The Scnn1b-Tg+ mouse model exhibits airway surface liquid (ASL) dehydration, impaired MCC, increased mucus production, and early spontaneous pulmonary bacterial infections. High morbidity and mortality among mucoobstructive disease patients, high economic and health burden, and lack of scientific understanding of the progression of mucoobstruction warrants in-depth investigation of the cause of mucoobstruction in mucoobstructive disease models. In this review, we will summarize published literature on the Scnn1b-Tg+ mouse and analyze various unanswered questions on the initiation and progression of mucobstruction and bacterial infections.

scholarly journals Pseudomonas aeruginosa PA14 Enhances the Efficacy of Norfloxacin against Staphylococcus aureus Newman Biofilms

2020 ◽  
Vol 202 (18) ◽  
Author(s):  
Giulia Orazi ◽  
Fabrice Jean-Pierre ◽  
George A. O’Toole
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Respiratory Infections ◽  
Multiple Infection ◽  
Bacterial Biofilms ◽  
Interspecies Interactions ◽  
Chronic Infections ◽  
Content Type

ABSTRACT The thick mucus within the airways of individuals with cystic fibrosis (CF) promotes frequent respiratory infections that are often polymicrobial. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent pathogens that cause CF pulmonary infections, and both are among the most common etiologic agents of chronic wound infections. Furthermore, the ability of P. aeruginosa and S. aureus to form biofilms promotes the establishment of chronic infections that are often difficult to eradicate using antimicrobial agents. In this study, we found that multiple LasR-regulated exoproducts of P. aeruginosa, including 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), siderophores, phenazines, and rhamnolipids, likely contribute to the ability of P. aeruginosa PA14 to shift S. aureus Newman norfloxacin susceptibility profiles. Here, we observe that exposure to P. aeruginosa exoproducts leads to an increase in intracellular norfloxacin accumulation by S. aureus. We previously showed that P. aeruginosa supernatant dissipates the S. aureus membrane potential, and furthermore, depletion of the S. aureus proton motive force recapitulates the effect of the P. aeruginosa PA14 supernatant on shifting norfloxacin sensitivity profiles of biofilm-grown S. aureus Newman. From these results, we hypothesize that exposure to P. aeruginosa PA14 exoproducts leads to increased uptake of the drug and/or an impaired ability of S. aureus Newman to efflux norfloxacin. Surprisingly, the effect observed here of P. aeruginosa PA14 exoproducts on S. aureus Newman susceptibility to norfloxacin seemed to be specific to these strains and this antibiotic. Our results illustrate that microbially derived products can alter the ability of antimicrobial agents to kill bacterial biofilms. IMPORTANCE Pseudomonas aeruginosa and Staphylococcus aureus are frequently coisolated from multiple infection sites, including the lungs of individuals with cystic fibrosis (CF) and nonhealing diabetic foot ulcers. Coinfection with P. aeruginosa and S. aureus has been shown to produce worse outcomes compared to infection with either organism alone. Furthermore, the ability of these pathogens to form biofilms enables them to cause persistent infection and withstand antimicrobial therapy. In this study, we found that P. aeruginosa-secreted products dramatically increase the ability of the antibiotic norfloxacin to kill S. aureus biofilms. Understanding how interspecies interactions alter the antibiotic susceptibility of bacterial biofilms may inform treatment decisions and inspire the development of new therapeutic strategies.

scholarly journals Spondylocarpotarsal synostosis syndrome due to a novel loss of function FLNB variant: a case report

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Samina Yasin ◽  
Outi Makitie ◽  
Sadaf Naz
Keyword(s):  
Short Stature ◽  
Autosomal Recessive ◽  
Autosomal Recessive Disorder ◽  
Loss Of Function ◽  
Case Presentation ◽  
Pathogenic Variants ◽  
Skeletal Malformations ◽  
Tarsal Bones ◽  
The Family ◽  
Heterozygous Carriers

Abstract Background Loss of function or gain of function variants of Filamin B (FLNB) cause recessive or dominant skeletal disorders respectively. Spondylocarpotarsal synostosis syndrome (SCT) is a rare autosomal recessive disorder characterized by short stature, fused vertebrae and fusion of carpal and tarsal bones. We present a novel FLNB homozygous pathogenic variant and present a carrier of the variant with short height. Case presentation We describe a family with five patients affected with skeletal malformations, short stature and vertebral deformities. Exome sequencing revealed a novel homozygous frameshift variant c.2911dupG p.(Ala971GlyfsTer122) in FLNB, segregating with the phenotype in the family. The variant was absent in public databases and 100 ethnically matched control chromosomes. One of the heterozygous carriers of the variant had short stature. Conclusion Our report expands the genetic spectrum of FLNB pathogenic variants. It also indicates a need to assess the heights of other carriers of FLNB recessive variants to explore a possible role in idiopathic short stature.

scholarly journals Mutation ofRv2887, amarR-Like Gene, Confers Mycobacterium tuberculosis Resistance to an Imidazopyridine-Based Agent

2015 ◽  
Vol 59 (11) ◽  
pp. 6873-6881 ◽  
Author(s):  
Kathryn Winglee ◽  
Shichun Lun ◽  
Marco Pieroni ◽  
Alan Kozikowski ◽  
William Bishai
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Targets ◽  
Efflux Pump ◽  
Transcriptional Regulator ◽  
Cross Resistance ◽  
Loss Of Function ◽  
Strong Activity ◽  
Content Type ◽  
Novel Drug

ABSTRACTDrug resistance is a major problem inMycobacterium tuberculosiscontrol, and it is critical to identify novel drug targets and new antimycobacterial compounds. We have previously identified an imidazo[1,2-a]pyridine-4-carbonitrile-based agent, MP-III-71, with strong activity againstM. tuberculosis. In this study, we evaluated mechanisms of resistance to MP-III-71. We derived three independentM. tuberculosismutants resistant to MP-III-71 and conducted whole-genome sequencing of these mutants. Loss-of-function mutations inRv2887were common to all three MP-III-71-resistant mutants, and we confirmed the role ofRv2887as a gene required for MP-III-71 susceptibility using complementation. The Rv2887 protein was previously unannotated, but domain and homology analyses suggested it to be a transcriptional regulator in the MarR (multiple antibiotic resistance repressor) family, a group of proteins first identified inEscherichia colito negatively regulate efflux pumps and other mechanisms of multidrug resistance. We found that two efflux pump inhibitors, verapamil and chlorpromazine, potentiate the action of MP-III-71 and that mutation ofRv2887abrogates their activity. We also used transcriptome sequencing (RNA-seq) to identify genes which are differentially expressed in the presence and absence of a functional Rv2887 protein. We found that genes involved in benzoquinone and menaquinone biosynthesis were repressed by functional Rv2887. Thus, inactivating mutations ofRv2887, encoding a putative MarR-like transcriptional regulator, confer resistance to MP-III-71, an effective antimycobacterial compound that shows no cross-resistance to existing antituberculosis drugs. The mechanism of resistance ofM. tuberculosisRv2887mutants may involve efflux pump upregulation and also drug methylation.

scholarly journals Vx-809/Vx-770 treatment reduces inflammatory response to Pseudomonas aeruginosa in primary differentiated cystic fibrosis bronchial epithelial cells

2018 ◽  
Vol 314 (4) ◽  
pp. L635-L641 ◽  
Author(s):  
Manon Ruffin ◽  
Lucie Roussel ◽  
Émilie Maillé ◽  
Simon Rousseau ◽  
Emmanuelle Brochiero
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Inflammatory Response ◽  
Respiratory Infections ◽  
Bronchial Epithelial Cell ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Bronchial Epithelial ◽  
Primary Bronchial Epithelial Cell ◽  
Beneficial Impact

Cystic fibrosis patients exhibit chronic Pseudomonas aeruginosa respiratory infections and sustained proinflammatory state favoring lung tissue damage and remodeling, ultimately leading to respiratory failure. Loss of cystic fibrosis transmembrane conductance regulator (CFTR) function is associated with MAPK hyperactivation and increased cytokines expression, such as interleukin-8 [chemoattractant chemokine (C-X-C motif) ligand 8 (CXCL8)]. Recently, new therapeutic strategies directly targeting the basic CFTR defect have been developed, and ORKAMBI (Vx-809/Vx-770 combination) is the only Food and Drug Administration-approved treatment for CF patients homozygous for the F508del mutation. Here we aimed to determine the effect of the Vx-809/Vx-770 combination on the induction of the inflammatory response by fully differentiated primary bronchial epithelial cell cultures from CF patients carrying F508del mutations, following exposure to P. aeruginosa exoproducts. Our data unveiled that CFTR functional rescue with Vx-809/Vx-770 drastically reduces CXCL8 (as well as CXCL1 and CXCL2) transcripts and p38 MAPK phosphorylation in response to P. aeruginosa exposure through a CFTR-dependent mechanism. These results suggest that ORKAMBI has anti-inflammatory properties that could decrease lung inflammation and contribute to the observed beneficial impact of this treatment in CF patients.

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