scholarly journals Hypercapnia modulates cAMP signalling and cystic fibrosis transmembrane conductance regulator-dependent anion and fluid secretion in airway epithelia

2015 ◽  
Vol 594 (6) ◽  
pp. 1643-1661 ◽  
Author(s):  
Mark J. Turner ◽  
Vinciane Saint-Criq ◽  
Waseema Patel ◽  
Salam H. Ibrahim ◽  
Bernard Verdon ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Fluid Secretion ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Airway Epithelia ◽  
Camp Signalling ◽  
Cystic Fibrosis Transmembrane

scholarly journals Infection by Toxoplasma gondii, a severe parasite in neonates and AIDS patients, causes impaired anion secretion in airway epithelia

2015 ◽  
Vol 112 (14) ◽  
pp. 4435-4440 ◽  
Author(s):  
Hong-Mei Guo ◽  
Jiang-Mei Gao ◽  
Yu-Li Luo ◽  
Yan-Zi Wen ◽  
Yi-Lin Zhang ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Toxoplasma Gondii ◽  
Infected Mouse ◽  
Inflammatory Responses ◽  
Short Circuit ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Airway Epithelia ◽  
Anion Secretion ◽  
Cystic Fibrosis Transmembrane

The airway epithelia initiate and modulate the inflammatory responses to various pathogens. The cystic fibrosis transmembrane conductance regulator-mediated Cl− secretion system plays a key role in mucociliary clearance of inhaled pathogens. We have explored the effects of Toxoplasma gondii, an opportunistic intracellular protozoan parasite, on Cl− secretion of the mouse tracheal epithelia. In this study, ATP-induced Cl− secretion indicated the presence of a biphasic short-circuit current (Isc) response, which was mediated by a Ca2+-activated Cl− channel (CaCC) and the cystic fibrosis transmembrane conductance regulator. However, the ATP-evoked Cl− secretion in T. gondii-infected mouse tracheal epithelia and the elevation of [Ca2+]i in T. gondii-infected human airway epithelial cells were suppressed. Quantitative reverse transcription–PCR revealed that the mRNA expression level of the P2Y2 receptor (P2Y2-R) increased significantly in T. gondii-infected mouse tracheal cells. This revealed the influence that pathological changes in P2Y2-R had on the downstream signal, suggesting that P2Y2-R was involved in the mechanism underlying T. gondii infection in airways. These results link T. gondii infection as well as other pathogen infections to Cl− secretion, via P2Y2-R, which may provide new insights for the treatment of pneumonia caused by pathogens including T. gondii.

scholarly journals A Rapid Membrane Potential Assay to Monitor CFTR Function and Inhibition

2013 ◽  
Vol 18 (9) ◽  
pp. 1132-1137 ◽  
Author(s):  
Rangan Maitra ◽  
Perumal Sivashanmugam ◽  
Keith Warner
Keyword(s):  
Cystic Fibrosis ◽  
Membrane Potential ◽  
Genetic Disorder ◽  
Fluid Secretion ◽  
Secretory Diarrhea ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Important Regulator ◽  
Cftr Protein ◽  
Cystic Fibrosis Transmembrane

The cystic fibrosis transmembrane conductance regulator (CFTR) protein is an important regulator of ion transport and fluid secretion in humans. Mutations to CFTR cause cystic fibrosis, which is a common recessive genetic disorder in Caucasians. Involvement of CFTR has been noted in other important diseases, such as secretory diarrhea and polycystic kidney disease. The assays to monitor CFTR function that have been described to date either are complicated or require specialized instrumentation and training for execution. In this report, we describe a rapid FlexStation-based membrane potential assay to monitor CFTR function. In this assay, agonist-mediated activation of CFTR results in membrane depolarization that can be monitored using a fluorescent membrane potential probe. Availability of a simple mix-and-read assay to monitor the function of this important protein might accelerate the discovery of CFTR ligands to study a variety of conditions.

Ion transport across the jejunum in normal and cystic fibrosis mice

1995 ◽  
Vol 268 (3) ◽  
pp. G505-G513 ◽  
Author(s):  
B. R. Grubb
Keyword(s):  
Cystic Fibrosis ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Fluid Secretion ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Targeted Disruption ◽  
Cl Secretion ◽  
Ion Substitution ◽  
Cystic Fibrosis Transmembrane

Cystic fibrosis (CF) mice created by targeted disruption of the murine cystic fibrosis transmembrane conductance regulator gene lack adenosine 3',5'-cyclic monophosphate (cAMP)-mediated Cl- secretion and exhibit marked intestinal complications secondary to inadequate fluid secretion. The basal short-circuit current (Isc) in the normal murine jejuna [43.2 +/- 5.9 microA.cm-2, n = 10 (mean +/- SE)] exhibits marked spontaneous n = 10 (mean +/- SE)] exhibits marked spontaneous oscillations (amplitude = 47.9 microA.cm-2, n = 18), which were completely absent in the CF jejunum. Treatment of normal jejuna with the neuronal blocker tetrodotoxin completely eliminated the oscillations and decreased the Isc to levels not significantly different from the low basal Isc (5.4 +/- 2.8 microA.cm-2, n = 16) exhibited by CF tissue. Ion substitution studies revealed basal Isc in normal jejuna to be due primarily to Cl- secretion but these tissues appeared to be capable of HCO3- secretion as well. In contrast, CF jejuna spontaneously secreted neither Cl- nor HCO3-, which may indicate that CF jejuna have a defect in the ability to secrete both of these anions. Apical glucose elicited an electrogenic absorption of Na+ of identical magnitude in normal and CF jejuna. Without apical glucose, CF jejuna exhibited a very small Isc response to forskolin (delta 2.2 +/- 0.67 microA.cm-2, n = 10). However, in the presence of apical glucose, forskolin elicited an eightfold greater Isc response in the CF tissue (delta 17.2 +/- 4.8 microA.cm-2, n = 9).(ABSTRACT TRUNCATED AT 250 WORDS)

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