Exosome-associated AAV vector as a robust and convenient neuroscience tool

Area of Science:

• Neuroscience
• Gene Therapy
• Molecular Biology

Background:

• Adeno-associated virus (AAV) vectors are crucial for gene therapy and neuroscience research.
• Current AAV purification methods are costly, labor-intensive, and time-consuming.
• AAV can associate with exosomes (exo-AAV) during isolation from producer cell media, showing increased resistance to neutralizing antibodies.

Purpose of the Study:

• To demonstrate that simple ultracentrifugation of exo-AAV yields high-titer vector preparations.
• To evaluate the efficiency of exo-AAV for transducing central nervous system (CNS) cells after systemic delivery in mice.
• To assess the potential of exo-AAV as a simplified and effective neuroscience research tool.

Main Methods:

• Isolation of AAV associated with exosomes (exo-AAV) from conditioned media.
• Purification of exo-AAV via simple ultracentrifugation and pelleting.
• Systemic injection of exo-AAV in mice to assess CNS transduction efficiency.
• Comparison of exo-AAV with conventionally purified AAV at low vector doses.
• Assessment of cellular toxicity and visualization of transduced cells using GFP fluorescence and two-photon tomography.

Main Results:

• Simple pelleting of exo-AAV resulted in high-titer vector preparations.
• Exo-AAV demonstrated more efficient gene delivery to the brain than conventional AAV at low doses, even for serotypes not typically crossing the blood-brain barrier.
• Similar cell types were transduced by both exo-AAV and conventional AAV.
• No cellular toxicity was observed in cells transduced with exo-AAV.
• Successful three-dimensional reconstruction of transduced Purkinje cells in the cerebellum was achieved.

Conclusions:

• Exo-AAV purification is simpler and more efficient than conventional methods.
• Exo-AAV facilitates effective gene delivery to the CNS after systemic administration, even for difficult-to-transduce serotypes.
• Exo-AAV evades neutralizing antibodies, making it clinically relevant for peripheral delivery to the CNS.
• The ease of isolation and high transduction efficiency position exo-AAV as a valuable tool for neuroscience research.