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Attenuation of oxidative stress in HL-1 cardiomyocytes improves mitochondrial function and stabilizes Hif-1alpha
Athanassios Vassilopoulos1, Panagiota Papazafiri
1Department of Animal and Human Physiology, School of Biology, Faculty of Sciences, University of Athens, Panepistimioupolis, 15784 Athens, Greece.
Insights
Antioxidants like LaT 3a protect heart cells from hypoxia-induced apoptosis by preserving mitochondrial function and stabilizing hypoxia-inducible factor-1alpha (Hif-1alpha) mRNA. This study highlights their potential in maintaining cell survival.
Area of Science:
- Cardiovascular Biology
- Cellular Stress Response
- Mitochondrial Medicine
Background:
- Hypoxia triggers apoptosis in cardiomyocytes, leading to reduced cell viability.
- Oxidative stress plays a critical role in hypoxia-induced cell death.
- Hypoxia-inducible factor-1alpha (Hif-1alpha) is a key regulator of the cellular response to low oxygen.
Purpose of the Study:
- To investigate the protective effects of antioxidants against hypoxia-induced apoptosis in HL-1 cardiomyocytes.
- To elucidate the mechanisms by which antioxidants preserve cell viability and function under hypoxic conditions.
- To determine the impact of antioxidants on Hif-1alpha stability during severe hypoxia.
Main Methods:
- HL-1 cardiomyocytes were exposed to simulated hypoxia with cobalt chloride.
- Cell viability, DNA laddering, ATP levels, mitochondrial membrane potential (MPTP), Bax translocation, and cytochrome c release were assessed.
- The effect of antioxidants (trolox, ascorbic acid, melatonin, LaT 3a) on these parameters was evaluated.
- Hif-1alpha mRNA levels were measured under severe hypoxia and oxidative stress conditions.
Main Results:
- Simulated hypoxia reduced cardiomyocyte viability and induced apoptosis, evidenced by DNA laddering.
- Antioxidants, particularly the hybrid compound LaT 3a, significantly increased cell viability.
- Antioxidant treatment restored ATP levels, prevented DNA fragmentation, inhibited MPTP opening, and blocked Bax translocation and cytochrome c release.
- Severe hypoxia destabilized Hif-1alpha mRNA, an effect attenuated by reducing oxidative stress.
Conclusions:
- Antioxidants protect cardiomyocytes from apoptosis by inhibiting the mitochondrial death pathway.
- Reducing oxidative stress stabilizes Hif-1alpha mRNA, suggesting an anti-apoptotic role for this hypoxia regulator.
- Antioxidants hold promise for maintaining cardiac cell function and survival under hypoxic stress.
Abstract:
HL-1 cardiomyocytes were subjected to simulated hypoxia, in the presence of cobalt chloride, which resulted in reduction of cell viability and induction of DNA laddering, indicating the activation of the apoptotic cascade. In the presence of trolox, ascorbic acid, melatonin and the hybrid compound of trolox and lipoic acid (LaT 3a), cell viability was increased, with LaT 3a exhibiting the best effect. Antioxidant treatment restored ATP levels, abolished laddering of DNA, abrogated MPTP opening, Bax translocation to the mitochondria and cytochrome c release to the cytoplasm. Moreover, severe hypoxia, was found to destabilize hypoxia inducible factor-1alpha (Hif-1alpha) mRNA. Reduction of oxidative stress attenuated this effect, implying a possible anti-apoptotic action of the master regulator of hypoxia response. Our data suggest that antioxidants can maintain cell function and survival by inhibiting the mitochondrial apoptotic pathway and stabilizing Hif-1alpha.
