Methylmercury Decreases AMPA Receptor Subunit GluA2 Levels in Cultured Rat Cortical Neurons

Area of Science:

• Neuroscience
• Environmental Toxicology
• Cell Biology

Background:

• Methylmercury (MeHg) is a potent neurotoxicant, but its molecular mechanisms at low concentrations remain unclear.
• Understanding MeHg's effects on neuronal function is crucial for public health.
• AMPA receptor subunit GluA2 influences neuronal Ca2+ permeability and is implicated in neurotoxicity.

Purpose of the Study:

• To investigate the effects of low-concentration MeHg on neuronal viability, Ca2+ homeostasis, and AMPA receptor GluA2 levels.
• To elucidate the molecular pathways involved in MeHg-induced neurotoxicity.
• To explore potential therapeutic interventions for MeHg toxicity.

Main Methods:

• Primary rat cortical neurons were exposed to 100 and 300 nM MeHg for 7 days.
• Assessed cell viability, intracellular Ca2+ concentration, and GluA2 levels.
• Examined the effects of glutamate stimulation and a specific AMPA receptor antagonist (1-naphthyl acetyl spermine).

Main Results:

• MeHg exposure decreased GluA2 levels and cell viability.
• Increased basal intracellular Ca2+ concentration and activated ERK1/2 and p38 pathways.
• Glutamate exacerbated MeHg's toxic effects, while the antagonist ameliorated neuronal death.

Conclusions:

• Decreased neuronal GluA2 levels and subsequent Ca2+ dysregulation contribute to MeHg neurotoxicity.
• Targeting Ca2+-permeable AMPA receptors may offer a therapeutic strategy against MeHg poisoning.
• This study provides insights into the molecular mechanisms of low-dose MeHg neurotoxicity.