Involvement of Cl(-)/HCO3(-) exchanger SLC26A3 and SLC26A6 in preimplantation embryo cleavage

Sci Rep. 2016 Jun 27:6:28402. doi: 10.1038/srep28402.

Abstract

Bicarbonate (HCO3(-)) is essential for preimplantation embryo development. However, the mechanism underlying the HCO3(-) transport into the embryo remains elusive. In the present study, we examined the possible involvement of Cl(-)/HCO3(-) exchanger in mediating HCO3(-) transport into the embryo. Our results showed that depletion of extracellular Cl(-), even in the presence of HCO3(-), suppressed embryo cleavage in a concentration-dependent manner. Cleavage-associated HCO3(-)-dependent events, including increase of intracellular pH, upregulation of miR-125b and downregulation of p53, also required Cl(-). We further showed that Cl(-)/HCO3(-) exchanger solute carrier family 26 (SLC26) A3 and A6 were expressed at 2-cell through blastocyst stage. Blocking individual exchanger's activity by inhibitors or gene knockdown differentially decreased embryo cleavage and inhibited HCO3(-)-dependent events, while inhibiting/knocking down both produced an additive effect to an extent similar to that observed when CFTR was inhibited. These results indicate the involvement of SLC26A3 and A6 in transporting HCO3(-) essential for embryo cleavage, possibly working in concert with CFTR through a Cl(-) recycling pathway. The present study sheds light into our understanding of molecular mechanisms regulating embryo cleavage by the female reproductive tract.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bicarbonates / metabolism*
  • Blastocyst / metabolism*
  • Chloride-Bicarbonate Antiporters / metabolism*
  • Chlorides / metabolism*
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • Membrane Transport Proteins / metabolism*
  • Mice
  • MicroRNAs / genetics
  • Pregnancy
  • Sulfate Transporters
  • Tumor Suppressor Protein p53 / genetics

Substances

  • Bicarbonates
  • CFTR protein, human
  • Chloride-Bicarbonate Antiporters
  • Chlorides
  • MIRN125 microRNA, human
  • Membrane Transport Proteins
  • MicroRNAs
  • SLC26A3 protein, human
  • SLC26A6 protein, human
  • Sulfate Transporters
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Cystic Fibrosis Transmembrane Conductance Regulator