Differences in the neurotoxicity profile induced by ATP and ATPgammaS in cultured cerebellar granule neurons

Area of Science:

• Neuroscience
• Cell Biology
• Pharmacology

Background:

• Extracellular adenosine triphosphate (ATP) and its P2 receptors are implicated in central nervous system (CNS) neurodegeneration.
• Understanding the specific mechanisms of ATP-induced neurotoxicity is crucial for developing therapeutic strategies.

Purpose of the Study:

• To investigate the biological effects and cytotoxic actions of the P2 receptor agonist ATPgammaS in neuronal cerebellar granule cultures.
• To compare the neurotoxic effects of ATPgammaS with ATP and elucidate the underlying mechanisms of cell death.

Main Methods:

• Neuronal cerebellar granule cultures were treated with ATPgammaS and ATP.
• Time-course experiments were conducted to assess cell death, receptor expression, enzyme activity, mitochondrial function, reactive oxygen species (ROS), and cyclic adenosine monophosphate (cAMP) levels.
• Pharmacological agents, including P2 receptor antagonists, were used to probe the mechanisms of toxicity.

Main Results:

• ATPgammaS induced 50-100% cell death within 15-24 hours at 500 microM.
• Toxicity was independent of NMDA receptor activation, ectonucleotidase activity, nucleoside transport, purine metabolism, and changes in P2X/P2Y receptor protein expression.
• Cell death correlated with lactate dehydrogenase release, inhibited intracellular dehydrogenase activity, transient cytochrome c outflow, increased ROS, and elevated cAMP levels.
• Pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid 4-sodium provided significant neuroprotection.

Conclusions:

• ATPgammaS induces neurodegeneration through mechanisms involving mitochondrial dysfunction and oxidative stress, distinct from classical purinergic signaling pathways.
• The findings highlight a novel pathway for ATP-induced neurotoxicity in the CNS.
• Specific P2 receptor antagonists show potential for neuroprotection against ATPgammaS-induced cell death.