Sex-independent expression of chloride/formate exchanger Cfex (Slc26a6) in rat pancreas, small intestine, and liver and male-dominant expression in kidneys

  • Dean Karaica Institute for Medical Research and Occupational Health, Zagreb
  • Davorka Breljak Institute for Medical Research and Occupational Health, Zagreb
  • Jovica Lončar Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute
  • Mila Lovrić Clinical Institute of Laboratory Diagnosis, University Hospital Center, Zagreb
  • Vedran Micek Institute for Medical Research and Occupational Health, Zagreb
  • Ivana Vrhovac Madunić Institute for Medical Research and Occupational Health, Zagreb
  • Hrvoje Brzica Institute for Medical Research and Occupational Health, Zagreb
  • Carol M. Herak-Kramberger Institute for Medical Research and Occupational Health, Zagreb
  • Jana Ivković Dupor Institute for Medical Research and Occupational Health, Zagreb
  • Marija Ljubojević Institute for Medical Research and Occupational Health, Zagreb
  • Tvrtko Smital Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute
  • Željka Vogrinc Clinical Institute of Laboratory Diagnosis, University Hospital Center, Zagreb
  • Gerhard Burckhardt Institute for Systemic Physiology and Pathophysiology, University Medical Center Göttingen, Göttingen
  • Birgitta C. Burckhardt Institute for Systemic Physiology and Pathophysiology, University Medical Center Göttingen, Göttingen
  • Ivan Sabolić Institute for Medical Research and Occupational Health, Zagreb
Keywords: anion exchanger, immunolocalisation, nephrolithiasis, oxaluria, RT-PCR, sex differences, urolithiasis

Abstract

Chloride/formate exchanger (CFEX; SLC26A6) mediates oxalate transport in various mammalian organs. Studies in Cfex knockout mice indicated its possible role in development of male-dominant hyperoxaluria and oxalate urolithiasis. Rats provide an important model for studying this pathophysiological condition, but data on Cfex (rCfex) localisation and regulation in their organs are limited. Here we applied the RT-PCR and immunochemical methods to investigate rCfex mRNA and protein expression and regulation by sex hormones in the pancreas, small intestine, liver, and kidneys from intact prepubertal and adult as well as gonadectomised adult rats treated with sex hormones. rCfex cDNA-transfected HEK293 cells were used to confirm the specificity of the commercial anti-CFEX antibody. Various biochemical parameters were measured in 24-h urine collected in metabolic cages. rCfex mRNA and related protein expression varied in all tested organs. Sex-independent expression of the rCfex protein was detected in pancreatic intercalated ducts (apical domain), small intestinal enterocytes (brush-border membrane; duodenum > jejunum > ileum), and hepatocytes (canalicular membrane). In kidneys, the rCfex protein was immunolocalised to the proximal tubule brush-border with segment-specific pattern (S1=S2<S3), and both rCfex mRNA and protein expression exhibited male-dominant sex differences driven by stimulatory effects of androgens after puberty. However, urinary oxalate excretion was unrelated to renal rCfex protein expression. While the effect of male-dominant expression of rCfex in renal proximal tubules on urine oxalate excretion remains unknown, its expression in the hepatocyte canalicular membrane may be a pathway of oxalate elimination via bile.

Published
2018-12-04
How to Cite
1.
Karaica D, Breljak D, Lončar J, Lovrić M, Micek V, Vrhovac Madunić I, Brzica H, Herak-Kramberger C, Ivković Dupor J, Ljubojević M, Smital T, Vogrinc Željka, Burckhardt G, Burckhardt B, Sabolić I. Sex-independent expression of chloride/formate exchanger Cfex (Slc26a6) in rat pancreas, small intestine, and liver and male-dominant expression in kidneys. AIHT [Internet]. 4Dec.2018 [cited 20Mar.2019];69(4). Available from: https://arhiv.imi.hr/index.php/arhiv/article/view/980
Section
Original article

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