title: Mechanosensitivity of wild-type and G551D cystic fibrosis transmembrane conductance regulator (CFTR) controls regulatory volume decrease in simple epithelia.
abstract: Mutations of cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial ligand-gated anion channel, are associated with the lethal genetic disease cystic fibrosis. The CFTR G551D mutation impairs ATP hydrolysis and thereby makes CFTR refractory to cAMP stimulation. Both wild-type (WT) and G551D CFTR have been implicated in regulatory volume decrease (RVD), but the underlying mechanism remains incompletely understood. Here, we show that the channel activity of both WT and G551D CFTR is directly stimulated by mechanical perturbation induced by cell swelling at the single-channel, cellular, and tissue levels. Hypotonicity activated CFTR single channels in cell-attached membrane patches and WT-CFTR-mediated short-circuit current (Isc) in Calu-3 cells, and this was independent of Ca(2+)and cAMP/PKA signaling. Genetic suppression and ablation but not G551D mutation of CFTR suppressed the hypotonicity- and stretch-inducedIscin Calu-3 cells and mouse duodena. Moreover, ablation but not G551D mutation of the CFTR gene inhibited the RVD of crypts isolated from mouse intestine; more importantly, CFTR-specific blockers markedly suppressed RVD in both WT- and G551D CFTR mice, demonstrating for the first time that the channel activity of both WT and G551D CFTR is required for epithelial RVD. Our findings uncover a previously unrecognized mechanism underlying CFTR involvement in epithelial RVD and suggest that the mechanosensitivity of G551D CFTR might underlie the mild phenotypes resulting from this mutation.-Xie, C., Cao, X., Chen, X, Wang, D., Zhang, W. K., Sun, Y., Hu, W., Zhou, Z., Wang, Y., Huang, P. Mechanosensitivity of wild-type and G551D cystic fibrosis transmembrane conductance regulator (CFTR) controls regulatory volume decrease in simple epithelia.
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Changyan
authors.initials: C
authors.lastname: Xie
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Cao
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Xibing
authors.initials: X
authors.lastname: Chen
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Wei Kevin
authors.initials: WK
authors.lastname: Zhang
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Wenbao
authors.initials: W
authors.lastname: Hu
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Zijing
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China bohuangp@ust.hk.
authors.forename: Pingbo
authors.initials: P
authors.lastname: Huang
mesh_terms: D000818:Animals; D016466:CHO Cells; D045744:Cell Line, Tumor; D048429:Cell Size / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007038:Hypotonic Solutions / Q000494:pharmacology; D015640:Ion Channel Gating / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D008465:Mechanoreceptors / Q000378:metabolism / Q000502:physiology*; D018345:Mice, Knockout; D009154:Mutation; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
chemical_list: D007038:Hypotonic Solutions; D019005:Cystic Fibrosis Transmembrane Conductance Regulator
keywords: hypotonicity; ion channel; mechanosensitive; osmotic swelling