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Updated: Jun 21, 2026

Functional Assessment of Intestinal Tight Junction Barrier and Ion Permeability in Native Tissue by Ussing Chamber Technique
Published on: May 26, 2021
Loss of TMEM16A causes a defect in epithelial Ca2+-dependent chloride transport
Jiraporn Ousingsawat1, Joana R Martins, Rainer Schreiber
1Institut für Physiologie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany.
Abstract:
Molecular identification of the Ca(2+)-dependent chloride channel TMEM16A (ANO1) provided a fundamental step in understanding Ca(2+)-dependent Cl(-) secretion in epithelia. TMEM16A is an intrinsic constituent of Ca(2+)-dependent Cl(-) channels in cultured epithelia and may control salivary output, but its physiological role in native epithelial tissues remains largely obscure. Here, we demonstrate that Cl(-) secretion in native epithelia activated by Ca(2+)-dependent agonists is missing in mice lacking expression of TMEM16A. Ca(2+)-dependent Cl(-) transport was missing or largely reduced in isolated tracheal and colonic epithelia, as well as hepatocytes and acinar cells from pancreatic and submandibular glands of TMEM16A(-/-) animals. Measurement of particle transport on the surface of tracheas ex vivo indicated largely reduced mucociliary clearance in TMEM16A(-/-) mice. These results clearly demonstrate the broad physiological role of TMEM16A(-/-) for Ca(2+)-dependent Cl(-) secretion and provide the basis for novel treatments in cystic fibrosis, infectious diarrhea, and Sjöegren syndrome.
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