P2X6 Knockout Mice Exhibit Normal Electrolyte Homeostasis

PLoS One. 2016 Jun 2;11(6):e0156803. doi: 10.1371/journal.pone.0156803. eCollection 2016.

Abstract

ATP-mediated signaling is an important regulator of electrolyte transport in the kidney. The purinergic cation channel P2X6 has been previously localized to the distal convoluted tubule (DCT), a nephron segment important for Mg2+ and Na+ reabsorption, but its role in ion transport remains unknown. In this study, P2x6 knockout (P2x6-/-) mice were generated to investigate the role of P2X6 in renal electrolyte transport. The P2x6-/- animals displayed a normal phenotype and did not differ physiologically from wild type mice. Differences in serum concentration and 24-hrs urine excretion of Na+, K+, Mg2+ and Ca2+ were not detected between P2x6+/+, P2x6+/- and P2x6-/- mice. Quantitative PCR was applied to examine potential compensatory changes in renal expression levels of other P2x subunits and electrolyte transporters, including P2x1-5, P2x7, Trpm6, Ncc, Egf, Cldn16, Scnn1, Slc12a3, Slc41a1, Slc41a3, Cnnm2, Kcnj10 and Fxyd2. Additionally, protein levels of P2X2 and P2X4 were assessed in P2x6+/+ and P2x6-/- mouse kidneys. However, significant changes in expression were not detected. Furthermore, no compensatory changes in gene expression could be demonstrated in heart material isolated from P2x6-/- mice. Except for a significant (P<0.05) upregulation of P2x2 in the heart of P2x6-/- mice compared to the P2x6+/+ mice. Thus, our data suggests that purinergic signaling via P2X6 is not significantly involved in the regulation of renal electrolyte handling under normal physiological conditions.

MeSH terms

  • Animals
  • Base Sequence
  • Behavior, Animal
  • Breeding
  • Electrolytes / metabolism*
  • Gene Expression Regulation
  • HEK293 Cells
  • Homeostasis*
  • Humans
  • Kidney / metabolism
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Mice, Knockout
  • Protein Subunits / metabolism
  • Receptors, Purinergic P2 / deficiency*
  • Receptors, Purinergic P2 / metabolism

Substances

  • Electrolytes
  • Membrane Transport Proteins
  • Protein Subunits
  • Receptors, Purinergic P2
  • purinoceptor P2X6

Grant support

This work was supported by grants from the Netherlands Organization for Scientific Research (NWO VICI 016.130.668) and the EURenOmics project from the European Union seventh Framework Programme (FP7/2007–2013, agreement no. 305608). Dr. Jeroen de Baaij is supported by grants from NWO (Rubicon 825.14.021) and the Dutch Kidney Foundation (Kolff 14OKG17). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.