BDNF local translation in viable synaptosomes: implication in spine maturation.

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Brain-derived neurotrophic factor (BDNF) plays crucial roles in neuronal function and survival.
• BDNF is encoded by distinct mRNA transcripts, including one with a long 3' untranslated region that localizes to dendrites.
• The translation and regulation of dendritic BDNF mRNA remain largely uncharacterized.

Purpose of the Study:

• To investigate the occurrence and regulation of BDNF translation in neuronal dendrites.
• To explore the potential role of dendritic BDNF translation in synaptic plasticity and spine maturation.

Main Methods:

• Utilized isolated synaptosomes to study translation independent of nuclear and other subcellular fractions.
• Stimulated synaptosomes with KCl (depolarization) or glutamate (excitation) to induce translation.
• Assessed BDNF translation and related signaling molecules using Western blotting.

Main Results:

• Depolarization and glutamate excitation induced BDNF translation in synaptosomes, similar to known dendritic mRNAs (CaMKllα, Homer, Arc).
• Synaptosomal BDNF translation was dependent on glucose concentration, TrkB receptor function, and intracellular calcium levels.
• KCl or glutamate treatment increased phospho-cofilin and phospho-PAK levels in synaptosomes, suggesting induction of spine maturation signaling.

Conclusions:

• BDNF translation occurs in dendrites and is regulated by neuronal activity, glucose, calcium, and TrkB signaling.
• Dendritic BDNF translation may be involved in initiating signaling pathways that lead to spine maturation and synaptic plasticity.