Hypoxia augments the calcium-activated chloride current carried by anoctamin-1 in cardiac vascular endothelial cells of neonatal mice

Br J Pharmacol. 2014 Aug;171(15):3680-92. doi: 10.1111/bph.12730.


Background and purpose: The molecular identity of calcium-activated chloride channels (CaCCs) in vascular endothelial cells remains unknown. This study sought to identify whether anoctamin-1 (Ano1, also known as TMEM16A) functions as a CaCC and whether hypoxia alters the biophysical properties of Ano1 in mouse cardiac vascular endothelial cells (CVECs).

Experimental approach: Western blot, quantitative real-time PCR, confocal imaging analysis and patch-clamp analysis combined with pharmacological approaches were used to determine whether Ano1 was expressed and functioned as CaCC in CVECs.

Key results: Ano1 was expressed in CVECs. The biophysical properties of the current generated in the CVECs, including the Ca(2+) and voltage dependence, outward rectification, anion selectivity and the pharmacological profile, are similar to those described for CaCCs. The density of ICl ( C a) detected in CVECs was significantly inhibited by T16Ainh -A01, an Ano1 inhibitor, and a pore-targeting, specific anti-Ano1 antibody, and was markedly decreased in Ano1 gene knockdown CVECs. The density of ICl ( C a) was significantly potentiated in CVECs exposed to hypoxia, and this hypoxia-induced increase in the density of ICl ( C a) was inhibited by T16Ainh -A01 or anti-Ano1 antibody. Hypoxia also increased the current density of ICl ( C a) in Ano1 gene knockdown CVECs.

Conclusions and implications: Ano1 formed CaCC in CVECs of neonatal mice. Hypoxia enhances Ano1-mediated ICl ( C a) density via increasing its expression, altering the ratio of its splicing variants, sensitivity to membrane voltage and to Ca(2+) . Ano1 may play a role in the pathophysiological processes during ischaemia in heart, and therefore, Ano1 might be a potential therapeutic target to prevent ischaemic damage.

Keywords: anoctamin; calcium-activated chloride channels; cardiac vascular endothelial cells; hypoxia.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Anoctamin-1
  • Base Sequence
  • Calcium / pharmacology
  • Cell Proliferation
  • Cells, Cultured
  • Chloride Channels / genetics
  • Chloride Channels / physiology*
  • Endothelial Cells / drug effects
  • Endothelial Cells / physiology*
  • Gene Silencing
  • Green Fluorescent Proteins / genetics
  • Heart Ventricles / cytology
  • Hypoxia / physiopathology*
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Transfection


  • ANO1 protein, mouse
  • Anoctamin-1
  • Chloride Channels
  • Green Fluorescent Proteins
  • Calcium

Associated data

  • GENBANK/A21206
  • GENBANK/A21209