Related Experiment Video
Updated: Jun 9, 2025
Author Spotlight: Tracing the Ferroptotic Signatures and Cell Death Dynamics in Medulloblastoma for Advanced Therapeutics
Published on: March 15, 2024
Role of ferroptosis in mitochondrial damage in diabetic retinopathy
Pooja Malaviya1, Jay Kumar1, Renu A Kowluru1
1Kresge Eye Institute, Wayne State University, Detroit, MI, USA.
Abstract:
Diabetic retinopathy is driven by oxidative stress-mitochondrial damage. Activation of ROS producing cytosolic NADPH oxidase 2 (Nox2) in diabetes precedes retinal mitochondrial damage, initiating a vicious cycle of free radicals. Elevated ROS levels peroxidize membrane lipids increasing damaging lipid peroxides (LPOs). While glutathione peroxidase 4 (GPx4) neutralizes LPOs, an imbalance in its generation-neutralization leads to ferroptosis, which is characterized by increased LPOs, free iron and decreased GPx4 activity. Mitochondria are rich in polyunsaturated fatty acids and iron and have mitochondrial isoform of GPx4. Our aim was to investigate mitochondrial ferroptosis in diabetic retinopathy, focusing on Nox2 mediated ROS production. Using human retinal endothelial cells, incubated in 5 mM or 20 mM D-glucose for 12-96 h, with or without Nox2 inhibitors (100 μM apocynin, 5 μM EHop-016 or 5 μM Gp91 ds-tat), or ferroptosis inhibitors (1 μM ferrostatin-1, 50 μM deferoxamine) or activator (0.1 μM RSL3), cytosolic and mitochondrial ROS, LPOs, iron, GPx4 activity, mitochondrial integrity (membrane permeability, oxygen consumption rate, mtDNA copy numbers) and cell death were quantified. High glucose significantly increased ROS, LPOs and iron levels and inhibited GPx4 activity in cytosol, and while Nox2 and ferroptosis inhibitors prevented glucose-induced increase in ferroptosis markers, mitochondrial damage and cell death, RSL3, further worsened them. Furthermore, high glucose also increased ferroptosis markers in the mitochondria, which followed their increase in the cytosol, suggesting a role of cytosolic ROS in mitochondrial ferroptosis. Thus, targeting Nox2-ferroptosis should help break down the self-perpetuating vicious cycle of free radicals, initiated by the damaged mitochondria, and could provide novel therapeutics to prevent/retard the development of diabetic retinopathy.
Insights
Diabetic retinopathy involves oxidative stress and mitochondrial damage. Targeting NADPH oxidase 2 (Nox2) and ferroptosis may break the cycle of free radicals, offering new therapies for diabetic retinopathy.
Area of Science:
- Biochemistry
- Cell Biology
- Ophthalmology
Background:
- Diabetic retinopathy (DR) is a complication of diabetes characterized by oxidative stress and mitochondrial damage.
- Activation of NADPH oxidase 2 (Nox2) produces reactive oxygen species (ROS), initiating a cycle of damage in retinal cells.
- This oxidative stress leads to lipid peroxidation and ferroptosis, a form of regulated cell death involving iron accumulation and lipid peroxides.
Purpose of the Study:
- To investigate the role of mitochondrial ferroptosis in diabetic retinopathy.
- To explore the contribution of Nox2-mediated ROS production to mitochondrial damage and ferroptosis in DR.
- To assess the therapeutic potential of targeting Nox2 and ferroptosis pathways in DR.
Main Methods:
- Human retinal endothelial cells were cultured under high glucose conditions (5 mM or 20 mM D-glucose).
- Cells were treated with Nox2 inhibitors (apocynin, EHop-016, Gp91 ds-tat), ferroptosis inhibitors (ferrostatin-1, deferoxamine), or an activator (RSL3).
- Quantification of cytosolic and mitochondrial ROS, lipid peroxides (LPOs), iron levels, glutathione peroxidase 4 (GPx4) activity, mitochondrial integrity, and cell death.
Main Results:
- High glucose significantly increased ROS, LPOs, and iron, while decreasing GPx4 activity in both cytosol and mitochondria.
- Nox2 and ferroptosis inhibitors attenuated glucose-induced ferroptosis markers, mitochondrial damage, and cell death.
- Ferroptosis markers increased in mitochondria following cytosolic increases, suggesting cytosolic ROS drives mitochondrial ferroptosis.
Conclusions:
- Nox2-mediated ROS production contributes to mitochondrial ferroptosis in diabetic retinopathy.
- Inhibiting Nox2 and ferroptosis pathways can prevent high glucose-induced mitochondrial damage and cell death.
- Targeting the Nox2-ferroptosis axis offers a promising therapeutic strategy for preventing or slowing the progression of diabetic retinopathy.
Related Concept Videos
01:16Necrosis
Morphological Manifestations of Necrosis
Necrotic cells show different types of morphological appearance depending on the type of tissue and infection. In coagulative necrosis, cells become...
01:46Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...