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TRPV4 and purinergic receptor signalling pathways are separately linked in airway epithelia to CFTR and TMEM16A chloride channels
Author(s) -
Genovese Michele,
Borrelli Anna,
Venturini Arianna,
Guidone Daniela,
Caci Emanuela,
Viscido Gaetano,
Gambardella Gennaro,
di Bernardo Diego,
Scudieri Paolo,
Galietta Luis J.V.
Publication year - 2019
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jp278784
Subject(s) - trpv4 , purinergic receptor , activator (genetics) , microbiology and biotechnology , intracellular , chloride channel , biology , respiratory epithelium , epithelium , extracellular , receptor , transient receptor potential channel , biochemistry , genetics
Key points Eact is a putative pharmacological activator of TMEM16A. Eact is strongly effective in recombinant Fischer rat thyroid (FRT) cells but not in airway epithelial cells with endogenous TMEM16A expression. Transcriptomic analysis, gene silencing and functional studies in FRT cells reveal that Eact is actually an activator of the Ca 2+ ‐permeable TRPV4 channel. In airway epithelial cells TRPV4 and TMEM16A are expressed in separate cell types. Intracellular Ca 2+ elevation by TRPV4 stimulation leads to CFTR channel activation.Abstract TMEM16A is a Ca 2+ ‐activated Cl − channel expressed in airway epithelial cells, particularly under conditions of mucus hypersecretion. To investigate the role of TMEM16A, we used Eact, a putative TMEM16A pharmacological activator. However, in contrast to purinergic stimulation, we found little effect of Eact on bronchial epithelial cells under conditions of high TMEM16A expression. We hypothesized that Eact is an indirect activator of TMEM16A. By a combination of approaches, including short‐circuit current recordings, bulk and single cell RNA sequencing, intracellular Ca 2+ imaging and RNA interference, we found that Eact is actually an activator of the Ca 2+ ‐permeable TRPV4 channel and that the modest effect of this compound in bronchial epithelial cells is due to a separate expression of TMEM16A and TRPV4 in different cell types. Importantly, we found that TRPV4 stimulation induced activation of the CFTR Cl − channel. Our study reveals the existence of separate Ca 2+ signalling pathways linked to different Cl − secretory processes.