TRPC1 regulates calcium-activated chloride channels in salivary gland cells

Yuyang Sun, Lutz Birnbaumer, Brij B Singh

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Calcium-activated chloride channel (CaCC) plays an important role in modulating epithelial secretion. It has been suggested that in salivary tissues, sustained fluid secretion is dependent on Ca2+ influx that activates ion channels such as CaCC to initiate Cl- efflux. However direct evidence as well as the molecular identity of the Ca2+ channel responsible for activating CaCC in salivary tissues is not yet identified. Here we provide evidence that in human salivary cells, an outward rectifying Cl- current was activated by increasing [Ca2+]i, which was inhibited by the addition of pharmacological agents niflumic acid (NFA), an antagonist of CaCC, or T16Ainh-A01, a specific TMEM16a inhibitor. Addition of thapsigargin (Tg), that induces store-depletion and activates TRPC1-mediated Ca2+ entry, potentiated the Cl- current, which was inhibited by the addition of a non-specific TRPC channel blocker SKF96365 or removal of external Ca2+. Stimulation with Tg also increased plasma membrane expression of TMEM16a protein, which was also dependent on Ca2+ entry. Importantly, in salivary cells, TRPC1 silencing, but not that of TRPC3, inhibited CaCC especially upon store depletion. Moreover, primary acinar cells isolated from submandibular gland also showed outward rectifying Cl- currents upon increasing [Ca2+]i. These Cl- currents were again potentiated with the addition of Tg, but inhibited in the presence of T16Ainh-A01. Finally, acinar cells isolated from the submandibular glands of TRPC1 knockout mice showed significant inhibition of the outward Cl- currents without decreasing TMEM16a expression. Together the data suggests that Ca2+ entry via the TRPC1 channels is essential for the activation of CaCC.

Original languageEnglish (US)
Pages (from-to)2848-2856
Number of pages9
JournalJournal of Cellular Physiology
Volume230
Issue number11
DOIs
StatePublished - Nov 1 2015
Externally publishedYes

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ASJC Scopus subject areas

  • Medicine(all)
  • Physiology
  • Clinical Biochemistry
  • Cell Biology

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