Oxidative stress induces mitochondrial iron overload and ferroptotic cell death

Area of Science:

• Cardiovascular Biology
• Cell Death Mechanisms
• Oxidative Stress Research

Background:

• Oxidative stress contributes to various cardiovascular diseases, including ischemia/reperfusion injury and heart failure.
• The precise mechanisms by which oxidative stress induces cardiomyocyte death are not fully understood.
• Existing knowledge does not clearly distinguish between ferroptosis, apoptosis, necroptosis, or necrosis in this context.

Purpose of the Study:

• To elucidate the specific type of cell death induced by oxidative stress in cardiomyocytes.
• To investigate the molecular pathways linking oxidative stress to ferroptosis.
• To identify potential therapeutic targets for preventing oxidative stress-induced cardiomyocyte death.

Main Methods:

• Treatment of cardiomyocytes with organic oxidants (tBHP, CHP) and hydrogen peroxide (H2O2).
• Assessment of glutathione levels, GPX4 activity, lipid peroxidation, and iron metabolism markers (Bach1, HO-1).
• Mitochondrial localization studies of HO-1 and manipulation of mitochondrial iron and ROS levels (using FTMT and mCAT).

Main Results:

• Organic oxidants, but not H2O2, induced ferroptosis in cardiomyocytes by depleting glutathione and degrading GPX4.
• Oxidative stress increased lipid peroxidation and labile iron through Bach1 downregulation and HO-1 upregulation.
• HO-1 mitochondrial translocation led to mitochondrial iron overload and ROS accumulation, which were mitigated by FTMT and mCAT.

Conclusions:

• Oxidative stress from organic oxidants, not H2O2, primarily causes ferroptosis in cardiomyocytes via GPX4 and Bach1/HO-1 pathways.
• Mitochondrial iron overload, mediated by HO-1 translocation, is a critical mechanism in oxidative stress-induced ferroptosis.
• Targeting mitochondrial iron or ROS presents a promising strategy for treating oxidative stress-related heart conditions.