TMEM16A deficiency: a potentially fatal neonatal disease resulting from impaired chloride currents

IntroductionTMEM16A is a calcium-activated chloride channel expressed in various secretory epithelia. Two siblings presented in early infancy with reduced intestinal peristalsis and recurrent episodes of haemorrhagic diarrhoea. In one of them, the episodes were characterised by hepatic pneumatosis with gas bubbles in the portal vein similar to necrotising enterocolitis of the newborn.MethodsExome sequencing identified a homozygous truncating pathogenic variant in ANO1. Expression analysis was performed using reverse transcription PCR, western blot and immunohistochemistry. Electrophysiological and cell biological studies were employed to characterise the effects on ion transport both in patient respiratory epithelial cells and in transfected HEK293 cells.ResultsThe identified variant led to TMEM16A dysfunction, which resulted in abolished calcium-activated Cl− currents. Secondarily, CFTR function is affected due to the close interplay between both channels without inducing cystic fibrosis (CF).ConclusionTMEM16A deficiency is a potentially fatal disorder caused by abolished calcium-activated Cl− currents in secretory epithelia. Secondary impairment of CFTR function did not cause a CF phenotyp, which may have implications for CF treatment.

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X-ray micro-analysis of cultured respiratory epithelial cells from patients with cystic fibrosis

Acta Physiologica Scandinavica ◽

10.1111/j.1748-1716.1992.tb09410.x ◽

1992 ◽

Vol 146 (2) ◽

pp. 213-220 ◽

Cited By ~ 16

Author(s):

S. SAGSTRÖM ◽

G. M. ROOMANS ◽

R. WROBLEWSKI ◽

J. L. M. KEULEMANS ◽

A. T. HOOGEVEEN ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Respiratory Epithelial Cells ◽

X Ray ◽

Respiratory Epithelial ◽

Micro Analysis

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Role of the cystic fibrosis transmembrane conductance regulator in internalization of Pseudomonas aeruginosa by polarized respiratory epithelial cells

Cellular Microbiology ◽

10.1111/j.1462-5822.2004.00380.x ◽

2004 ◽

Vol 6 (6) ◽

pp. 521-533 ◽

Cited By ~ 27

Author(s):

Katharine E. A. Darling ◽

Ann Dewar ◽

Thomas J. Evans

Keyword(s):

Cystic Fibrosis ◽

Pseudomonas Aeruginosa ◽

Epithelial Cells ◽

Transmembrane Conductance Regulator ◽

Transmembrane Conductance ◽

Respiratory Epithelial Cells ◽

Respiratory Epithelial ◽

Cystic Fibrosis Transmembrane

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Cystic fibrosis–adaptedPseudomonas aeruginosaquorum sensinglasRmutants cause hyperinflammatory responses

Science Advances ◽

10.1126/sciadv.1500199 ◽

2015 ◽

Vol 1 (6) ◽

pp. e1500199 ◽

Cited By ~ 55

Author(s):

Shantelle L. LaFayette ◽

Daniel Houle ◽

Trevor Beaudoin ◽

Gabriella Wojewodka ◽

Danuta Radzioch ◽

...

Keyword(s):

Cystic Fibrosis ◽

Lung Disease ◽

Inflammatory Responses ◽

Pulmonary Inflammation ◽

Opportunistic Pathogen ◽

Respiratory Epithelial Cells ◽

Adaptive Mutations ◽

Cystic Fibrosis Lung Disease ◽

Airway Infections ◽

Respiratory Epithelial

Cystic fibrosis lung disease is characterized by chronic airway infections with the opportunistic pathogenPseudomonas aeruginosaand severe neutrophilic pulmonary inflammation.P. aeruginosaundergoes extensive genetic adaptation to the cystic fibrosis (CF) lung environment, and adaptive mutations in the quorum sensing regulator genelasRcommonly arise. We sought to define how mutations inlasRalter host-pathogen relationships. We demonstrate thatlasRmutants induce exaggerated host inflammatory responses in respiratory epithelial cells, with increased accumulation of proinflammatory cytokines and neutrophil recruitment due to the loss of bacterial protease–dependent cytokine degradation. In subacute pulmonary infections,lasRmutant–infected mice show greater neutrophilic inflammation and immunopathology compared with wild-type infections. Finally, we observed that CF patients infected withlasRmutants have increased plasma interleukin-8 (IL-8), a marker of inflammation. These findings suggest that bacterial adaptive changes may worsen pulmonary inflammation and directly contribute to the pathogenesis and progression of chronic lung disease in CF patients.

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X-Ray Microanalysis of Respiratory Epithelial Cells in the Study of Cystic Fibrosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135368 ◽

1990 ◽

Vol 48 (2) ◽

pp. 352-353

Author(s):

Godfried M. Roomans ◽

Samuel Sagström ◽

Joke L.M. Ceulemans ◽

Jan Bijman

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Water Transport ◽

Clinical Symptoms ◽

Chloride Secretion ◽

Tracheal Mucosa ◽

Respiratory Epithelial Cells ◽

X Ray ◽

Airway Infections ◽

Respiratory Epithelial

One of the most important clinical symptoms associated with cystic fibrosis (CF) is obstructive airway disease and recurrent airway infections. The smaller airways in CF patients are blocked by viscous mucus, and infections are common and difficult to manage. Generally, lung disease is directly or indirectly the cause of death in CF. The viscous mucus in CF is likely to be a result of defective water transport in the respiratory epithelium. Water transport is coupled to chloride secretion, and it is strongly suspected that a defective chloride channel in the apical membrane of the respiratory epithelial cells is the basic error in CF. We therefore studied changes in the intracellular concentration of chloride (and other ions) by x-ray microanalysis of cultured respiratory epithelial cells under a variety of conditions.Tissues were obtained from material excised during polypectomy. The tracheal mucosa was digested with collagenase and the dispersed cells were plated onto Milliporefilters coated with human placental collagen.

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Moxifloxacin but not ciprofloxacin or azithromycin selectively inhibits IL-8, IL-6, ERK1/2, JNK, and NF-κB activation in a cystic fibrosis epithelial cell line

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00030.2006 ◽

2007 ◽

Vol 292 (1) ◽

pp. L343-L352 ◽

Cited By ~ 39

Author(s):

Hannah Blau ◽

Keren Klein ◽

Itamar Shalit ◽

Drora Halperin ◽

Ina Fabian

Keyword(s):

Cystic Fibrosis ◽

Cell Line ◽

Lung Diseases ◽

Epithelial Cell Line ◽

Respiratory Epithelial Cells ◽

Mapk Activation ◽

Chronic Lung Diseases ◽

Phosphorylated Form ◽

Tnf Α ◽

Respiratory Epithelial

Cystic fibrosis (CF) is associated with severe neutrophilic airway inflammation. We showed that moxifloxacin (MXF) inhibits IL-8 and MAPK activation in monocytic and respiratory epithelial cells. Azithromycin (AZM) and ciprofloxacin (CIP) are used clinically in CF. Thus we now examined effects of MXF, CIP, and AZM directly on CF cells. IB3, a CF bronchial cell line, and corrected C38 cells were treated with TNF-α, IL-1β, or LPS with or without 5–50 μg/ml MXF, CIP, or AZM. IL-6 and IL-8 secretion (ELISA), MAPKs ERK1/2, JNK, p38, and p65 NF-κB (Western blot) activation were measured. Baseline IL-6 was sixfold higher in IB3 than C38 cells but IL-8 was similar. TNF-α and IL-1β increased IL-6 and IL-8 12- to 67-fold with higher levels in IB3 than C38 cells post-TNF-α ( P < 0.05). Levels were unchanged following LPS. Baseline phosphorylated form of ERK1/2 (p-ERK1/2), JNK, and NF-κB p65 were higher in IB3 than C38 cells (5-, 1.4-, and 1.4-fold), and following TNF-α increased, as did the p-p38, by 1.6- to 2-fold. MXF (5–50 μg/ml) and CIP (50 μg/ml), but not AZM, suppressed IL-6 and IL-8 secretion by up to 69%. MXF inhibited TNF-α-stimulated MAPKs ERK1/2, 46-kDa JNK, and NF-κB up to 60%, 40%, and 40%, respectively. In contrast, MXF did not inhibit p38 activation, implying a highly selective pretranslational effect. In conclusion, TNF-α and IL-1β induce an exaggerated inflammatory response in CF airway cells, inhibited by MXF more than by CIP or AZM. Clinical trials are recommended to assess efficacy in CF and other chronic lung diseases.

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