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The Ca 2+ ‐Activated Chloride Channel TMEM16A Colocalizes with CFTR Chloride Channels in Rodent Secretory Airway Epithelial Cells
Author(s) -
Hahn Anne K,
Faulhaber Johannes,
Srisawang Lalita,
Salomon Johanna J,
Mall Marcus M,
Möhrlen Frank,
Frings Stephan
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1007.8
Subject(s) - chloride channel , cystic fibrosis , submucosal glands , secretion , respiratory epithelium , cystic fibrosis transmembrane conductance regulator , epithelium , respiratory system , immunohistochemistry , pathology , apical membrane , biology , chemistry , microbiology and biotechnology , medicine , endocrinology , immunology , anatomy
There is a variety of animal models available to study cystic fibrosis, a disease caused by mutations in the CFTR gene. However, the applicability of these models is limited as CFTR −/− mice and also CFTR deficient rats fail to recapitulate phenotypic features of the human disease in the lung. One reason may be compensatory effects of Ca 2+ ‐mediated Cl − secretion in airway epithelia. The purpose of this study was to investigate whether the chloride channel TMEM16A accounts for the molecular basis of Ca 2+ ‐activated Cl − conductance in rodent airway epithelia. Furthermore, the spatial expression of the chloride channels, TMEM16A and CFTR, was studied in tissue of the respiratory system of rats and mice. Rat tracheal epithelial cells were cultured under air‐liquid culture conditions for at least 14 days and subsequently the short circuit current (I SC ) was measured in Ussing chambers. For immunohistochemical stainings, respiratory epithelia of the nose, trachea and lungs of mice and rats were co‐stained using anti‐TMEM16A and anti‐CFTR antibodies in combination with markers for different epithelial cell types (e.g. ciliated cells, goblet cells, club cells) Bioelectrical studies revealed that the UTP‐induced increase in I SC reflecting the Ca 2+ ‐activated Cl − secretion was significantly inhibited by 95% after preincubation with the specific TMEM16A inhibitor Ani9 (I SC values of 0,6 ± 0,5 μA/cm 2 (pretreated) vs.12,6 ± 4,3 μA/cm 2 (non‐treated)) in rat tracheal epithelial cells. In contrast to human airway epithelia, immunohistochemical stainings in rodents showed a colocalization of TMEM16A and CFTR in secretory epithelial cells throughout the respiratory system. Both channels were not expressed in ciliated cells. In conclusion, TMEM16A inhibitor Ani9 selectively inhibits UTP‐induced Ca 2+ ‐activated Cl − ‐ currents accounting for TMEM16A‐mediated Cl − conductance. The colocalization of TMEM16A and CFTR in secretory cells of rodents suggests a potential regulatory interaction. Support or Funding Information Studienstiftung des deutschen Volkes