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Updated: Jul 2, 2025
Primary Culture of Mouse Dopaminergic Neurons
Published on: September 8, 2014
Metformin Attenuates Manganese-Induced Oxidative Stress in N27-A Dopaminergic Neuronal Cells
Jae-Sung Kim1, Jeong-Yeon Seo1, Kyeong-Rok Kang1
1The Institute of Dental Science, School of Dentistry, Chosun University.
Abstract:
Metformin is an anti-diabetic drug that exerts protective effects against neurodegenerative diseases. In this study, we investigated the protective effects of metformin against manganese (Mn)-induced cytotoxicity associated with Parkinson's disease-like symptoms in N27-A dopaminergic (DA) cells. Metformin (0.1-1 mM) suppressed Mn (0.4 mM)-induced cell death in a concentration-dependent manner. Metformin pretreatment effectively suppressed the Mn-mediated increase in the levels of oxidative stress markers, such as reactive oxygen species (ROS) and thiobarbituric acid reactive substances. Moreover, metformin restored the levels of the antioxidants, superoxide dismutase, intracellular glutathione, and glutathione peroxidase, which were reduced by Mn. Metformin (0.5 mM) significantly attenuated the decrease in sirtuin-1 (SIRT1) and peroxisome proliferator activated receptor gamma coactivator-1 alpha levels, which were increased by Mn (0.4 mM). In addition, metformin inhibited the expression of microRNA-34a, which directly targeted SIRT1. Metformin also inhibited the loss of Mn-induced mitochondrial membrane potential (ΔΨm) and activation of the apoptosis marker, caspase-3. Furthermore, metformin-mediated inhibition of ROS generation and caspase-3 activation, recovery of ΔΨm, and restoration of cell viability were partially reversed by the SIRT1 inhibitor, Ex527. These results suggest that metformin may protects against Mn-induced DA neuronal cell death mediated by oxidative stress and mitochondrial dysfunction possibly via the regulation of SIRT1 pathway.
Insights
Metformin protects against manganese-induced Parkinson's disease-like symptoms in dopaminergic cells by reducing oxidative stress and improving mitochondrial function. This neuroprotection is linked to the sirtuin-1 pathway.
Area of Science:
- Neuroscience
- Pharmacology
- Toxicology
Background:
- Metformin, an anti-diabetic drug, shows promise in combating neurodegenerative diseases.
- Manganese exposure can induce Parkinson's disease-like symptoms by damaging dopaminergic cells.
Purpose of the Study:
- To investigate metformin's protective effects against manganese-induced cytotoxicity in dopaminergic cells.
- To elucidate the mechanisms underlying metformin's neuroprotection, focusing on oxidative stress and mitochondrial function.
Main Methods:
- N27-A dopaminergic cells were exposed to manganese (Mn) with or without metformin pretreatment.
- Assessed cell viability, oxidative stress markers (ROS, TBARS), antioxidant levels (SOD, GSH, GPx), SIRT1 and PGC-1α expression, microRNA-34a levels, mitochondrial membrane potential (ΔΨm), and caspase-3 activation.
- Utilized a SIRT1 inhibitor (Ex527) to confirm pathway involvement.
Main Results:
- Metformin dose-dependently suppressed Mn-induced cell death.
- Metformin reduced oxidative stress markers and restored antioxidant levels.
- Metformin attenuated the decrease in SIRT1 and PGC-1α, inhibited microRNA-34a, preserved mitochondrial membrane potential, and reduced caspase-3 activation.
- SIRT1 inhibition partially reversed metformin's protective effects.
Conclusions:
- Metformin protects against Mn-induced dopaminergic cell death.
- Neuroprotection involves mitigating oxidative stress and mitochondrial dysfunction.
- The sirtuin-1 pathway plays a crucial role in metformin's protective mechanism against manganese neurotoxicity.
