Synaptosomes: new vesicles for neuronal mitochondrial transplantation.

Area of Science:

• Neuroscience
• Cell Biology
• Mitochondrial Medicine

Background:

• Mitochondrial dysfunction is a key factor in neurodegenerative diseases.
• Mitochondrial transplantation is a promising therapeutic strategy.
• Synaptosomes, derived from rat brain synaptic terminals, contain mitochondria and are proposed as novel delivery systems.

Purpose of the Study:

• To investigate the potential of synaptosomes as natural vehicles for mitochondrial delivery into neuronal cells.
• To assess the viability and functionality of mitochondria transferred via synaptosomes.
• To evaluate the therapeutic potential of synaptosome-mediated mitochondrial replacement in disease models.

Main Methods:

• Synaptosome preparation and characterization (Synaptophysin, PSD95, size, zeta potential).
• Cellular uptake studies using labeled synaptosomes in LAN5 cells.
• Assessment of mitochondrial vitality (Opa1, Fis1, TOM40, JC-1) and function restoration.
• Confirmation of mitochondrial transfer using microscopy and molecular markers (cytochrome c, Hexokinase II, rat mtDNA).

Main Results:

• Synaptosomes were successfully prepared and characterized, showing efficient internalization into recipient neuronal cells via protein-protein interactions.
• Transferred mitochondria within synaptosomes remained viable and functional, evidenced by specific protein markers and membrane potential.
• Synaptosomes delivered functional mitochondria, restoring mitochondrial function in cells with rotenone or CCCP-induced damage.
• Evidence of successful mitochondrial transfer included increased levels of key mitochondrial proteins and the presence of rat mitochondrial DNA in recipient cells.

Conclusions:

• Synaptosomes serve as effective natural carriers for delivering molecules and organelles, including functional mitochondria, to neuronal cells.
• This approach holds potential for therapeutic applications in treating neurodegenerative diseases linked to mitochondrial dysfunction.
• Synaptosome-mediated mitochondrial replacement represents a novel strategy for restoring neuronal health.