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Author Spotlight: Understanding DNA Damage Response in Mammalian Oocytes and Preimplantation Embryos
Published on: June 23, 2023
DNA damage and S phase arrest induced by Ochratoxin A in human embryonic kidney cells (HEK 293)
Qian Yang1, Xiaoyun He2, Xiaohong Li1
1Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
Abstract:
Ochratoxin A (OTA) is a ubiquitous mycotoxin with potential nephrotoxic, hepatotoxic and immunotoxic effects. The mechanisms underlying the nephrotoxicity of OTA remain obscure. To investigate DNA damage and the changes of the cell cycle distribution induced by OTA, human embryonic kidney cells (HEK 293 cells) were incubated with various concentrations of OTA for 24h in vitro. The results indicated that OTA treatment led to the production of reactive oxygen species (ROS) and to a decrease of the mitochondrial membrane potential (ΔΨm). OTA-induced DNA damage in HEK 293 cells was evidenced by DNA comet tails formation and increased expression of γ-H2AX. In addition, OTA could induce cell cycle arrest at the S phase in HEK 293 cells. The expression of key cell cycle regulatory factors that were critical to the S phase, including cyclin A2, cyclin E1, and CDK2, were further detected. The expression of cyclin A2, cyclin E1, and CDK2 were significantly decreased by OTA treatment at both the mRNA and protein levels. The apoptosis of HEK 293 cells after OTA treatment was observed using Hoechst 33342 staining. The results confirmed that OTA did induce apoptosis in HEK 293 cells. In conclusion, our results provided new insights into the molecular mechanisms by which OTA might promote nephrotoxicity.
Insights
Ochratoxin A (OTA) causes kidney cell damage by increasing reactive oxygen species and DNA damage, leading to cell cycle arrest and apoptosis. These findings clarify molecular mechanisms of OTA-induced nephrotoxicity.
Area of Science:
- Toxicology
- Molecular Biology
- Cell Biology
Background:
- Ochratoxin A (OTA) is a widespread mycotoxin with known toxic effects, but its mechanisms of kidney toxicity are not fully understood.
- Investigating cellular responses to OTA is crucial for understanding its nephrotoxic potential.
Purpose of the Study:
- To investigate the effects of Ochratoxin A (OTA) on DNA damage, cell cycle distribution, and apoptosis in human embryonic kidney (HEK 293) cells.
- To elucidate the molecular mechanisms underlying OTA-induced nephrotoxicity.
Main Methods:
- HEK 293 cells were exposed to varying concentrations of OTA in vitro.
- Assessed reactive oxygen species (ROS) production, mitochondrial membrane potential (ΔΨm), DNA damage (comet assay, γ-H2AX), cell cycle distribution, expression of cell cycle regulators (cyclin A2, E1, CDK2), and apoptosis (Hoechst staining).
Main Results:
- OTA induced ROS production and decreased mitochondrial membrane potential in HEK 293 cells.
- OTA caused DNA damage, evidenced by comet tail formation and increased γ-H2AX expression.
- OTA triggered S-phase cell cycle arrest and apoptosis, accompanied by decreased expression of cyclin A2, cyclin E1, and CDK2 at both mRNA and protein levels.
Conclusions:
- OTA induces significant DNA damage, oxidative stress, and apoptosis in kidney cells.
- OTA disrupts cell cycle regulation by downregulating key proteins like cyclin A2, cyclin E1, and CDK2.
- These findings provide novel insights into the molecular pathways of OTA-induced nephrotoxicity.
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