Manganese disrupts astrocyte glutamine transporter expression and function.

Area of Science:

• Neuroscience
• Neurotoxicology
• Cellular Metabolism

Background:

• Glutamine (Gln) is vital for brain energy metabolism and neurotransmitter synthesis.
• Astrocytic Gln transport is known to be affected by manganese (Mn) exposure.
• Understanding the specific transporters involved in Mn-induced impairment is crucial.

Purpose of the Study:

• To identify the specific Gln transport routes affected by Mn exposure.
• To determine the Gln transporters responsible for Mn-induced transport impairment in astrocytes.

Main Methods:

• Primary astrocyte cultures from neonatal rats were treated with Mn.
• Gln uptake and export assays were performed.
• mRNA and protein expression levels of key Gln transporters (SNAT3, SNAT2, LAT2, ASCT2, SNAT5, LAT1) were analyzed.

Main Results:

• Mn exposure significantly decreased Gln uptake via systems N and ASC.
• Mn treatment reduced Gln export efficiency for systems N, ASC, and L.
• Mn exposure lowered mRNA and protein levels of SNAT3, SNAT2, and LAT2, and protein levels of ASCT2.
• Expression of SNAT5 and LAT1 remained unaffected by Mn exposure.

Conclusions:

• Mn-induced impairment of inward and outward Gln transport is primarily due to reduced expression of specific Gln transporters.
• Deregulation of glutamate homeostasis and reduced neuronal glutamate availability result from impaired Gln transport.
• These findings elucidate a key mechanism underlying Mn-induced neurotoxicity and glutamatergic neurotransmission deficits.