p-cresyl sulphate has pro-inflammatory and cytotoxic actions on human proximal tubular epithelial cells

Nephrol Dial Transplant. 2014 Jan;29(1):56-64. doi: 10.1093/ndt/gft367. Epub 2013 Oct 28.


Background: p-Cresyl sulphate (p-CS) and p-cresyl glucuronide (p-CG) are uraemic toxins that exhibit pro-inflammatory features in leukocytes and are associated with the progression of chronic kidney disease (CKD). Tubular cells are key targets of nephrotoxic agents and tubular cell death and activation contribute to the progression of CKD. However, the potential toxicity of these compounds on tubular cells is not fully understood. More specifically, apoptosis has never been studied.

Methods: HK-2 human proximal tubular epithelial cells were studied. Cell death was evaluated by flow cytometry of DNA content and by morphology. Gene expression was studied by real-time (RT)-PCR. Protein expression was studied by western blot and flow cytometry.

Results: Long-term (7 days) exposure to p-CS induced apoptosis in HK-2 cells in a concentration-dependent manner. In addition, short-term (3 h) exposure to p-CS promoted the expression of the TWEAK receptor Fn14, cooperated with TWEAK in promoting cell death and increased inflammatory gene expression. Albumin was cytotoxic and increased the inflammatory response to p-CS concentrations found in the circulation of non-dialysis CKD patients. In contrast, no biological actions of p-CG were observed on HK-2 cells, either alone or in combination with p-CS.

Conclusions: This study demonstrates for the first time that p-CS has pro-apoptotic and pro-inflammatory effects on tubular cells. These results identify mechanisms by which uraemic toxicity may contribute to CKD progression.

Keywords: apoptosis; cell death; fn14; inflammation; tweak; uraemic toxins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Cell Death / physiology
  • Cells, Cultured
  • Cresols / pharmacology*
  • Disease Progression
  • Epithelial Cells / metabolism
  • Humans
  • Kidney Tubules, Proximal / cytology*
  • Kidney Tubules, Proximal / drug effects*
  • Kidney Tubules, Proximal / metabolism
  • Real-Time Polymerase Chain Reaction
  • Receptors, Tumor Necrosis Factor / metabolism
  • Renal Insufficiency, Chronic / metabolism
  • Sulfuric Acid Esters / pharmacology*
  • TWEAK Receptor


  • Cresols
  • Receptors, Tumor Necrosis Factor
  • Sulfuric Acid Esters
  • TNFRSF12A protein, human
  • TWEAK Receptor
  • 4-cresol sulfate