Expression of aquaporin-3 in human peritoneal mesothelial cells and its up-regulation by glucose in vitro

Kidney Int. 2002 Oct;62(4):1431-9. doi: 10.1111/j.1523-1755.2002.kid564.x.

Abstract

Background: Aquaporin-3 (AQP3) is a member of the water channel family that is selective for the passage of not only water, but also glycerol and urea. Our recent study demonstrated the presence of aquaporin-1 in human peritoneal mesothelial cells (HPMC). Although transcripts encoding for AQP3 has been detected by reverse transcription-polymerase chain reaction (RT-PCR) in murine peritoneal mesothelium, to date there is no documentation of protein expression on peritoneal mesothelial cells.

Method: Our present study was designed to explore the gene and protein expression of AQP3 in HPMC and its regulation under different concentrations of glucose.

Results: AQP3 protein was detected in the human peritoneal tissue by immunohistological staining using specific, affinity-purified polyclonal anti-AQP3 antibodies. AQ3 transcripts and protein expression in cultured HPMC were investigated by RT-PCR and immunoblotting analysis respectively. Cell permeability to glycerol (flux) was measured using [(14)C]glycerol incorporation. AQP3 transcript and protein were weakly expressed in HPMC constitutively. The gene expression of AQP3 and its protein biosynthesis in HPMC were inducible following exposure to glucose in a dose- and time-dependent manner (P < 0.0001). Glucose at a concentration of 200 mmol induced glycerol flux by 4.82-fold above the control value (P < 0.0001) and its effect was significantly inhibited by mercuric chloride (P < 0.01).

Conclusion: Our novel observation demonstrated the AQP3 expression and biosynthesis in HPMC and in vitro studies revealed that glycerol permeability in HPMC was up-regulated by glucose. Further study is warranted to elucidate the role of AQP3 in HPMC for maintaining the ultrafiltration of the peritoneal membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aquaporin 3
  • Aquaporins / analysis
  • Aquaporins / genetics*
  • Carbon Radioisotopes
  • Cell Membrane Permeability / drug effects
  • Cells, Cultured
  • Diuretics, Osmotic / pharmacology
  • Epithelial Cells / chemistry
  • Epithelial Cells / cytology
  • Epithelial Cells / physiology*
  • Gene Expression / drug effects
  • Glucose / pharmacology*
  • Glycerol / pharmacokinetics
  • Humans
  • Immunoblotting
  • In Vitro Techniques
  • Mannitol / pharmacology
  • Peritoneum / cytology*
  • Up-Regulation / drug effects

Substances

  • AQP3 protein, human
  • Aquaporins
  • Carbon Radioisotopes
  • Diuretics, Osmotic
  • Aquaporin 3
  • Mannitol
  • Glucose
  • Glycerol