Related Experiment Video
Updated: Jun 13, 2025
Real-Time Analysis of Bioenergetics in Primary Human Retinal Pigment Epithelial Cells Using High-Resolution Respirometry
Published on: February 3, 2023
Metformin Alleviates Inflammation and Induces Mitophagy in Human Retinal Pigment Epithelium Cells Suffering from
Maija Toppila1,2, Sofia Ranta-Aho1, Kai Kaarniranta2,3
1School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland.
Abstract:
Mitochondrial malfunction, excessive production of reactive oxygen species (ROS), deficient autophagy/mitophagy, and chronic inflammation are hallmarks of age-related macular degeneration (AMD). Metformin has been shown to activate mitophagy, alleviate inflammation, and lower the odds of developing AMD. Here, we explored the ability of metformin to activate mitophagy and alleviate inflammation in retinal pigment epithelium (RPE) cells. Human ARPE-19 cells were pre-treated with metformin for 1 h prior to exposure to antimycin A (10 µM), which induced mitochondrial damage. Cell viability, ROS production, and inflammatory cytokine production were measured, while autophagy/mitophagy proteins were studied using Western blotting and immunocytochemistry. Metformin pre-treatment reduced the levels of proinflammatory cytokines IL-6 and IL-8 to 42% and 65% compared to ARPE-19 cells exposed to antimycin A alone. Metformin reduced the accumulation of the autophagy substrate SQSTM1/p62 (43.9%) and the levels of LC3 I and II (51.6% and 48.6%, respectively) after antimycin A exposure. Metformin also increased the colocalization of LC3 with TOM20 1.5-fold, suggesting active mitophagy. Antimycin A exposure increased the production of mitochondrial ROS (226%), which was reduced by the metformin pre-treatment (84.5%). Collectively, metformin showed anti-inflammatory and antioxidative potential with mitophagy induction in human RPE cells suffering from mitochondrial damage.
Insights
Metformin activates mitophagy and reduces inflammation and oxidative stress in retinal pigment epithelium cells, offering potential benefits for age-related macular degeneration (AMD). This study demonstrates metformin
Area of Science:
- Cell Biology
- Molecular Biology
- Ophthalmology
Background:
- Age-related macular degeneration (AMD) is characterized by mitochondrial dysfunction, oxidative stress, impaired mitophagy, and inflammation.
- Metformin is known to activate mitophagy, reduce inflammation, and potentially lower AMD risk.
Purpose of the Study:
- To investigate metformin's capacity to induce mitophagy and reduce inflammation in retinal pigment epithelium (RPE) cells.
- To assess metformin's effects on mitochondrial damage, reactive oxygen species (ROS) production, and inflammatory responses in RPE cells.
Main Methods:
- Human ARPE-19 cells were pre-treated with metformin before exposure to antimycin A to induce mitochondrial damage.
- Evaluated cell viability, ROS production, inflammatory cytokine levels (IL-6, IL-8), and autophagy/mitophagy proteins (SQSTM1/p62, LC3, TOM20) using Western blotting and immunocytochemistry.
Main Results:
- Metformin pre-treatment significantly reduced IL-6 and IL-8 levels by 42% and 65%, respectively.
- Metformin decreased SQSTM1/p62 accumulation by 43.9% and LC3 I/II levels by 51.6% and 48.6%.
- Metformin increased LC3-TOM20 colocalization 1.5-fold, indicating mitophagy induction, and reduced mitochondrial ROS production by 84.5% from a 226% increase.
Conclusions:
- Metformin exhibits anti-inflammatory and antioxidant properties in RPE cells under mitochondrial stress.
- Metformin effectively induces mitophagy, mitigating mitochondrial damage and associated inflammatory responses.
- These findings suggest metformin's therapeutic potential for AMD by targeting key pathological mechanisms.
More Related Videos
07:04Author Spotlight: Assessment of Mitophagy Flux in Pancreatic β-Cells Using Effective and Robust Complementary Approaches
Published on: September 15, 2023
08:39Experimental Protocol for Detecting Mitochondrial Function in Hepatocytes Exposed to Organochlorine Pesticides
Published on: September 16, 2020
