In Vitro hRPTEC TERT1 Model for Uranium-Induced Nephrotoxicity Pathway Study

Area of Science:

• Toxicology and Pharmacology
• Renal Cell Biology
• Environmental Health

Background:

• Uranium (U(VI)), a heavy metal and alpha emitter, poses significant chemical and radiological toxicity risks, primarily targeting the kidneys.
• The precise mechanisms of uranium-induced renal failure remain incompletely understood, particularly through the lens of the Adverse Outcome Pathway (AOP) approach.
• Understanding these mechanisms is crucial for developing effective strategies to mitigate uranium's nephrotoxic effects.

Purpose of the Study:

• To investigate the molecular mechanisms underlying uranium (U(VI))-induced kidney toxicity using an in vitro model of human renal proximal tubule epithelial cells (hRPTEC TERT1).
• To contribute to the development of the Adverse Outcome Pathway (AOP) for kidney toxicity.
• To identify key events at the gene and protein levels associated with uranium exposure, including oxidative stress, apoptosis, inflammation, and cell survival.

Main Methods:

• Utilized a specialized in vitro model of human renal proximal tubule epithelial cells (hRPTEC TERT1).
• Determined U(VI) concentrations inducing apoptosis (Caspase 3/7 activity) and necrosis (LDH assay).
• Analyzed gene and protein expression levels related to oxidative stress (ROS), apoptosis, cell survival, inflammation (TNFα, IL-6, IL-18), and kidney injury biomarkers (KIM-1).

Main Results:

• Apoptosis was induced from 300 μM U(VI), and necrosis from 500 μM, with an IC50 of 420 μM after 48h exposure.
• Uranium exposure led to early oxidative stress (ROS production) and subsequent antioxidant responses.
• Higher U(VI) concentrations (> 300 μM) triggered significant inflammatory responses and increased caspase 3/7 and LDH activities, with a slight increase in KIM-1 protein.

Conclusions:

• This study successfully generated a multiplex panel detailing key events in the AOP of uranium-induced renal failure using a relevant human kidney cell model.
• The findings elucidate the dose-dependent effects of U(VI) on renal cells, highlighting oxidative stress and inflammation as critical contributors to nephrotoxicity.
• This research provides a foundation for further investigation into uranium's renal toxicity and the development of targeted interventions.