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Published on: May 10, 2022
Zinc protects HeLa-tat cells against free radical cytotoxicity induced by glucose
Patrice Faure1, Sophie Bouvard, Corinne Roucard
1Laboratoire HP2, Faculté de Médecine, Université Joseph Fourier, 38000 Grenoble, France. patrice.faure@ujf-grenoble.fr
Abstract:
In the present study, we investigated the protective effect of zinc on the glucose-induced cytotoxicity in HeLa wild and HeLa-tat cells (30 and 20 mmol/l glucose, respectively). HeLa cells transfected with the protein Tat exhibit a lower antioxidant defense system. Incubation of HeLa wild and HeLa-tat cells with high glucose levels led to a rapid increase in generation of reactive oxygen species (ROS). As expected in the presence of high glucose concentrations, the viability was reduced for both cell lines. The redox status essentially regulated by thiol groups may play an important role in the apoptotic process. Thus, we developed a new method using the p-nitrophenyl disulfide to measure cytosolic thiol groups in intact cells. Cellular zinc was measured using inductively coupled plasma mass spectrometry. Intracellular thiol groups and intracellular zinc concentrations were significantly lower in HeLa cells cultured in hyperglycemic conditions, and their concentrations were significantly lower in HeLa-tat cells than in HeLa wild cells. However, the generation of ROS and the induction of apoptosis by a glucose specific mechanism were prevented by zinc (50 micromol/l) and the intracellular thiol groups and zinc concentrations significantly increased in both cell lines to become similar to the initial values. These results suggest that the glucose oxidation and its subsequent effects on the cells can be prevented by a biological antioxidant such as zinc.
Insights
Zinc supplementation protects against high glucose-induced cell damage by reducing reactive oxygen species (ROS) and preventing apoptosis. This study highlights zinc
Area of Science:
- Biochemistry
- Cell Biology
- Toxicology
Background:
- High glucose levels induce cytotoxicity in cells, partly due to increased reactive oxygen species (ROS) generation.
- HeLa cells transfected with the Tat protein show a diminished antioxidant defense system.
- Redox status, particularly thiol groups, is crucial in regulating apoptosis.
Purpose of the Study:
- To investigate the protective effects of zinc against glucose-induced cytotoxicity in HeLa wild and HeLa-tat cells.
- To explore the role of intracellular thiol groups and zinc concentrations in cellular response to hyperglycemia.
- To develop and utilize a novel method for measuring cytosolic thiol groups.
Main Methods:
- Cell culture of HeLa wild and HeLa-tat cells under varying glucose concentrations.
- Measurement of reactive oxygen species (ROS) generation.
- Quantification of intracellular thiol groups using p-nitrophenyl disulfide assay.
- Determination of intracellular zinc concentrations via inductively coupled plasma mass spectrometry.
- Assessment of cell viability and apoptosis induction.
Main Results:
- Hyperglycemic conditions significantly increased ROS generation and reduced cell viability in both cell lines.
- Intracellular thiol groups and zinc concentrations were lower in hyperglycemic conditions and in HeLa-tat cells compared to HeLa wild cells.
- Zinc supplementation (50 micromol/l) effectively prevented ROS generation and apoptosis induction.
- Zinc treatment restored intracellular thiol and zinc concentrations to normal levels in both cell lines.
Conclusions:
- Zinc acts as a biological antioxidant, protecting cells from glucose-induced oxidative stress and apoptosis.
- Maintaining adequate intracellular zinc and thiol levels is critical for cellular defense against hyperglycemia.
- Zinc supplementation may be a therapeutic strategy to mitigate hyperglycemia-related cellular damage.
