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Exploring the oxidative stress response mechanism triggered by environmental water samples
Peta A Neale1, Maud E S Achard, Beate I Escher
1Australian Rivers Institute, Griffith School of Environment, Griffith University, Southport, QLD 4222, Australia. f.leusch@griffith.edu.au.
Environmental Science. Processes & Impacts
|December 24, 2016
Summary
This study investigated how environmental water contaminants trigger oxidative stress responses in human liver cells. While reactive oxygen species (ROS) were often involved, some water samples activated cellular defenses through other mechanisms, requiring further research.
Area of Science:
- Environmental toxicology
- Cellular stress responses
- Biomarker detection
Background:
- Environmental waters harbor diverse micropollutants, necessitating robust toxicity assessment methods.
- Bioanalytical assays, including those for oxidative stress, are crucial for evaluating cellular responses to water contaminants.
- The Nrf2-antioxidant response element (ARE) pathway is a key cellular defense mechanism, but its activation by water contaminants can be triggered by reactive oxygen species (ROS) or electrophiles, leading to mechanistic ambiguity.
Purpose of the Study:
- To elucidate the mechanisms underlying oxidative stress responses induced by surface water extracts.
- To differentiate between ROS-dependent and ROS-independent activation of the Nrf2-ARE pathway by environmental water contaminants.
- To assess the role of glutathione (GSH) levels and ROS formation in cellular responses to river water extracts and specific chemicals.
Main Methods:
- Human liver cells were exposed to surface water extracts and individual detected chemicals.
- Assays were performed to measure reactive oxygen species (ROS) formation.
- Changes in glutathione (GSH) and glutathione disulfide (GSSG) concentrations were quantified.
Main Results:
- Many surface water samples induced significant ROS formation and decreased the GSH/GSSG ratio, indicating ROS as a key mechanism.
- Some highly responsive samples and individual chemicals did not significantly alter ROS levels or the GSH/GSSG ratio, suggesting alternative activation pathways.
- The Nrf2-ARE pathway activation in response to water contaminants may involve both ROS-dependent and Nrf2-independent mechanisms.
Conclusions:
- Reactive oxygen species (ROS) play a significant role in the oxidative stress response induced by many environmental water samples.
- The Nrf2-antioxidant response element (ARE) pathway can be activated by mechanisms other than ROS, including Nrf2-independent pathways and direct antioxidant effects.
- Further research is needed to fully characterize the specific chemicals and mechanisms responsible for ARE pathway activation in environmental samples.
- Bioanalytical test batteries remain valuable for assessing integrated cellular responses to complex environmental mixtures.
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