Perfluorooctane sulfonate induces neuronal vulnerability by decreasing GluR2 expression.

Area of Science:

• Environmental Science
• Neuroscience
• Toxicology

Background:

• Perfluorooctane sulfonate (PFOS) is a persistent environmental contaminant with known neurotoxic effects.
• The molecular mechanisms and developmental neurotoxicity of PFOS remain unclear, particularly regarding its distribution and impact during critical developmental stages.

Purpose of the Study:

• To investigate the molecular mechanisms underlying PFOS-induced neurotoxicity during developmental periods.
• To examine the effect of PFOS on glutamate receptor 2 (GluR2) expression and neuronal vulnerability in primary cortical neurons and neonatal rat brains.

Main Methods:

• Primary cortical neurons were exposed to PFOS (1 μM) for 9 days.
• Neonatal rat brains were analyzed for PFOS distribution, GluR2 expression, and response to kainic acid after PFOS exposure (2.0 mg/kg).
• Intracellular calcium concentrations were measured to assess neuronal vulnerability.

Main Results:

• PFOS exposure led to decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR2 expression in cortical neurons.
• This decrease in GluR2 enhanced neuronal vulnerability to glutamate, evidenced by increased intracellular Ca2+.
• In neonatal rats, PFOS showed a higher brain-plasma ratio in pups than dams, and PFOS exposure reduced cortical GluR2 expression, leading to histopathological abnormalities upon kainic acid challenge.

Conclusions:

• Decreased neuronal GluR2 expression is a key mechanism in PFOS-induced neurotoxicity.
• Developing brains, particularly during fetal and neonatal periods, are highly vulnerable to PFOS exposure.
• PFOS accumulation in the brain during development poses a significant risk for neurodevelopmental abnormalities.