Sertoli cell expression of the cystic fibrosis transmembrane conductance regulator

1998 ◽  
Vol 274 (4) ◽  
pp. C922-C930 ◽  
Author(s):  
Fredric R. Boockfor ◽  
Rebecca A. Morris ◽  
Dennis C. DeSimone ◽  
D. Margaret Hunt ◽  
Kenneth B. Walsh
Keyword(s):  
Cystic Fibrosis ◽  
Sertoli Cell ◽  
Sertoli Cells ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Patch Clamp Technique ◽  
Immunoreactive Material ◽  
Normal Spermatogenesis ◽  
Cell Expression ◽  
Cystic Fibrosis Transmembrane

Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene have been associated with a number of male reproductive problems, including testis abnormalities and a reduction in germ cell quality and number. To establish at least one site of functional CFTR expression in the testis, we subjected cultured Sertoli cells to analysis of message, protein, and channel activity for CFTR. With reverse transcription-polymerase chain reaction, we obtained evidence for the presence of CFTR RNA when CFTR primers were used with RNA from cultured Sertoli cells. Western analysis performed with both anti-R and anti-C domain CFTR antibodies revealed immunoreactive material in extracts from primary Sertoli cell cultures that seemed consistent with CFTR previously identified in other cells and tissues. This led us to perform more detailed studies using the whole cell arrangement of the patch-clamp technique. Application of the membrane-soluble cAMP analog, 8-chlorophenylthio-cAMP, resulted in the activation of a Cl− current that displayed a permeability sequence of Br− > I− ≥ Cl− and was blocked by diphenylamine-2-carboxylate and glibenclamide. In addition, a 13-pS conductance Cl− channel was measured in excised membrane patches exposed to the catalytic subunit of protein kinase A. When taken together, our findings of evidence of CFTR message, immunoreactive material that appeared consistent with CFTR, and Cl− channels with properties similar to those reported for CFTR provide strong evidence that Sertoli cells express a functional CFTR-like protein. The presence of CFTR in these cells may be needed to maintain the specific nutritional and fluid balance in the seminiferous tubule that is vital for normal spermatogenesis.

scholarly journals Defective function of the cystic fibrosis-causing missense mutation G551D is recovered by genistein

1999 ◽  
Vol 277 (4) ◽  
pp. C833-C839 ◽  
Author(s):  
Beate Illek ◽  
Lei Zhang ◽  
Nancy C. Lewis ◽  
Richard B. Moss ◽  
Jian-Yun Dong ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Transmembrane Conductance Regulator ◽  
Wild Type ◽  
Adrenergic Stimulation ◽  
Transmembrane Conductance ◽  
Patch Clamp Technique ◽  
Open Probability ◽  
Nasal Potential Difference ◽  
Cystic Fibrosis Transmembrane

The patch-clamp technique was used to investigate the effects of the isoflavone genistein on disease-causing mutations (G551D and ΔF508) of the cystic fibrosis transmembrane conductance regulator (CFTR). In HeLa cells recombinantly expressing the trafficking-competent G551D-CFTR, the forskolin-stimulated Cl currents were small, and average open probability of G551D-CFTR was P o = 0.047 ± 0.019. Addition of genistein activated Cl currents ∼10-fold, and the P o of G551D-CFTR increased to 0.49 ± 0.12, which is a P o similar to wild-type CFTR. In cystic fibrosis (CF) epithelial cells homozygous for the trafficking-impaired ΔF508 mutation, forskolin and genistein activated Cl currents only after 4-phenylbutyrate treatment. These data suggested that genistein activated CFTR mutants that were present in the cell membrane. Therefore, we tested the effects of genistein in CF patients with the G551D mutation in nasal potential difference (PD) measurements in vivo. The perfusion of the nasal mucosa of G551D CF patients with isoproterenol had no effect; however, genistein stimulated Cl-dependent nasal PD by, on average, −2.4 ± 0.6 mV, which corresponds to 16.9% of the responses (to β-adrenergic stimulation) found in healthy subjects.

scholarly journals Potentiation of the cystic fibrosis transmembrane conductance regulator Cl− channel by ivacaftor is temperature independent

2018 ◽  
Vol 315 (5) ◽  
pp. L846-L857 ◽  
Author(s):  
Yiting Wang ◽  
Zhiwei Cai ◽  
Martin Gosling ◽  
David N. Sheppard
Keyword(s):  
Cystic Fibrosis ◽  
Temperature Dependence ◽  
Single Channel ◽  
Channel Gating ◽  
Transmembrane Conductance Regulator ◽  
Wild Type ◽  
Transmembrane Conductance ◽  
Patch Clamp Technique ◽  
Open Probability ◽  
Cystic Fibrosis Transmembrane

Ivacaftor is the first drug to target directly defects in the cystic fibrosis transmembrane conductance regulator (CFTR), which causes cystic fibrosis (CF). To understand better how ivacaftor potentiates CFTR channel gating, here we investigated the effects of temperature on its action. As a control, we studied the benzimidazolone UCCF-853, which potentiates CFTR by a different mechanism. Using the patch-clamp technique and cells expressing recombinant CFTR, we studied the single-channel behavior of wild-type and F508del-CFTR, the most common CF mutation. Raising the temperature of the intracellular solution from 23 to 37°C increased the frequency but reduced the duration of wild-type and F508del-CFTR channel openings. Although the open probability ( Po) of wild-type CFTR increased progressively as temperature was elevated, the relationship between Po and temperature for F508del-CFTR was bell-shaped with a maximum Po at ~30°C. For wild-type CFTR and to a greatly reduced extent F508del-CFTR, the temperature dependence of channel gating was asymmetric with the opening rate demonstrating greater temperature sensitivity than the closing rate. At all temperatures tested, ivacaftor and UCCF-853 potentiated wild-type and F508del-CFTR. Strikingly, ivacaftor but not UCCF-853 abolished the asymmetric temperature dependence of CFTR channel gating. At all temperatures tested, Po values of wild-type CFTR in the presence of ivacaftor were approximately double those of F508del-CFTR, which were equivalent to or greater than those of wild-type CFTR at 37°C in the absence of the drug. We conclude that the principal effect of ivacaftor is to promote channel opening to abolish the temperature dependence of CFTR channel gating.

scholarly journals Permeability of Wild-Type and Mutant Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channels to Polyatomic Anions

1997 ◽  
Vol 110 (4) ◽  
pp. 355-364 ◽  
Author(s):  
Paul Linsdell ◽  
Joseph A. Tabcharani ◽  
Johanna M. Rommens ◽  
Yue-Xian Hou ◽  
Xiu-Bao Chang ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Channels ◽  
Single Channel ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Site Directed Mutagenesis ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Patch Clamp Technique ◽  
Cystic Fibrosis Transmembrane

Permeability of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel to polyatomic anions of known dimensions was studied in stably transfected Chinese hamster ovary cells by using the patch clamp technique. Biionic reversal potentials measured with external polyatomic anions gave the permeability ratio (PX/PCl) sequence NO3− > Cl− > HCO3− > formate > acetate. The same selectivity sequence but somewhat higher permeability ratios were obtained when anions were tested from the cytoplasmic side. Pyruvate, propanoate, methane sulfonate, ethane sulfonate, and gluconate were not measurably permeant (PX/PCl < 0.06) from either side of the membrane. The relationship between permeability ratios from the outside and ionic diameters suggests a minimum functional pore diameter of ∼5.3 Å. Permeability ratios also followed a lyotropic sequence, suggesting that permeability is dependent on ionic hydration energies. Site-directed mutagenesis of two adjacent threonines in TM6 to smaller, less polar alanines led to a significant (24%) increase in single channel conductance and elevated permeability to several large anions, suggesting that these residues do not strongly bind permeating anions, but may contribute to the narrowest part of the pore.

scholarly journals Aquaporin-9 is expressed in rat Sertoli cells and interacts with the cystic fibrosis transmembrane conductance regulator

IUBMB Life ◽  
2014 ◽  
Vol 66 (9) ◽  
pp. 639-644 ◽  
Author(s):  
Tito T. Jesus ◽  
Raquel L. Bernardino ◽  
Ana D. Martins ◽  
Rosália Sá ◽  
Mário Sousa ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Sertoli Cells ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Aquaporin 9 ◽  
Cystic Fibrosis Transmembrane

scholarly journals Halide Permeation in Wild-Type and Mutant Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channels

1997 ◽  
Vol 110 (4) ◽  
pp. 341-354 ◽  
Author(s):  
Joseph A. Tabcharani ◽  
Paul Linsdell ◽  
John W. Hanrahan
Keyword(s):  
Cystic Fibrosis ◽  
Field Strength ◽  
Weak Field ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Patch Clamp Technique ◽  
Pipette Solution ◽  
Anion Selectivity ◽  
Wide Range ◽  
Cystic Fibrosis Transmembrane

Permeation of cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channels by halide ions was studied in stably transfected Chinese hamster ovary cells by using the patch clamp technique. In cell-attached patches with a high Cl− pipette solution, the CFTR channel displayed outwardly rectifying currents and had a conductance near the membrane potential of 6.0 pS at 22°C or 8.7 pS at 37°C. The current–voltage relationship became linear when patches were excised into symmetrical, N-tris(hydroxymethyl)methyl-2-aminomethane sulfonate (TES)-buffered solutions. Under these conditions, conductance increased from 7.0 pS at 22°C to 10.9 pS at 37°C. The conductance at 22°C was ∼1.0 pS higher when TES and HEPES were omitted from the solution, suggesting weak, voltage-independent block by pH buffers. The relationship between conductance and Cl− activity was hyperbolic and well fitted by a Michaelis-Menten–type function having a Km of ∼38 mM and maximum conductance of 10 pS at 22°C. Dilution potentials measured with NaCl gradients indicated high anion selectivity (PNa/PCl = 0.003–0.028). Biionic reversal potentials measured immediately after exposure of the cytoplasmic side to various test anions indicated PI (1.8) > PBr (1.3) > PCl (1.0) > PF (0.17), consistent with a “weak field strength” selectivity site. The same sequence was obtained for external halides, although inward F− flow was not observed. Iodide currents were protocol dependent and became blocked after 1–2 min. This coincided with a large shift in the (extrapolated) reversal potential to values indicating a greatly reduced I−/Cl− permeability ratio (PI/PCl < 0.4). The switch to low I− permeability was enhanced at potentials that favored Cl− entry into the pore and was not observed in the R347D mutant, which is thought to lack an anion binding site involved in multi-ion pore behavior. Interactions between Cl− and I− ions may influence I− permeation and be responsible for the wide range of PI/PCl ratios that have been reported for the CFTR channel. The low PI/PCl ratio usually reported for CFTR only occurred after entry into an altered permeability state and thus may not be comparable with permeability ratios for other anions, which are obtained in the absence of iodide. We propose that CFTR displays a “weak field strength” anion selectivity sequence.

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