Selective Activation of Endoplasmic Reticulum Stress by Reactive-Oxygen-Species-Mediated Ochratoxin A-Induced Apoptosis in Tubular Epithelial Cells

Int J Mol Sci. 2021 Oct 11;22(20):10951. doi: 10.3390/ijms222010951.

Abstract

Ochratoxin A (OTA), one of the major food-borne mycotoxins, impacts the health of humans and livestock by contaminating food and feed. However, the underlying mechanism of OTA nephrotoxicity remains unknown. This study demonstrated that OTA induced apoptosis through selective endoplasmic reticulum (ER) stress activation in human renal proximal tubular cells (HK-2). OTA increased ER-stress-related JNK and precursor caspase-4 cleavage apoptotic pathways. Further study revealed that OTA increased reactive oxygen species (ROS) levels, and N-acetyl cysteine (NAC) could reduce OTA-induced JNK-related apoptosis and ROS levels in HK-2 cells. Our results demonstrate that OTA induced ER stress-related apoptosis through an ROS-mediated pathway. This study provides new evidence to clarify the mechanism of OTA-induced nephrotoxicity.

Keywords: ER stress; HK-2 cell; apoptosis; ochratoxin A; reactive oxygen species.

MeSH terms

  • Apoptosis / drug effects*
  • Cell Cycle Checkpoints / drug effects
  • Cell Line
  • Cell Survival / drug effects
  • Endoplasmic Reticulum Stress / drug effects*
  • Endoribonucleases / metabolism
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • Humans
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Kidney Tubules, Proximal / cytology
  • Kidney Tubules, Proximal / metabolism
  • Ochratoxins / pharmacology*
  • Oxidative Stress / drug effects
  • Protein Serine-Threonine Kinases / metabolism
  • Reactive Oxygen Species / metabolism*

Substances

  • Ochratoxins
  • Reactive Oxygen Species
  • ochratoxin A
  • ERN1 protein, human
  • Protein Serine-Threonine Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Endoribonucleases