Drug Development

Area of Science:

• Neuroscience
• Immunology
• Biotechnology

Background:

• Alzheimer's disease (AD) is characterized by amyloid-beta (Aβ) plaque accumulation, leading to neurodegeneration.
• Current antibody therapies face limitations due to the blood-brain barrier (BBB) and limited brain penetration.
• Camelid nanobodies (VHHs) offer improved BBB penetration and brain diffusion for targeting Aβ.

Purpose of the Study:

• To develop and evaluate two novel immunotherapy strategies for AD using the anti-Aβ VHH R3VQ.
• To enhance the delivery of anti-Aβ VHHs across the BBB and within brain tissue.
• To assess the efficacy of R3VQ in an established AD mouse model (APP-PS1-KI).

Main Methods:

• R3VQ was engineered into monomeric, dimeric, and Fc-conjugated formats.
• In vivo studies utilized APP-PS1-KI mice to evaluate Aβ targeting and diffusion.
• Two delivery strategies were employed: transient BBB opening via LIPU and microbubbles, and in situ brain production using AAVr vectors.

Main Results:

• In vitro, R3VQ demonstrated effective binding to fibrillar and soluble Aβ, inhibiting aggregation.
• In vivo, R3VQ variants successfully labeled Aβ deposits and showed wider brain diffusion than conventional IgGs.
• Preliminary data indicate R3VQ crosses the BBB post-LIPU, binds plaques, and enters neurons; AAV delivery yields robust astrocytic expression.

Conclusions:

• This study presents innovative passive immunotherapy approaches for AD targeting Aβ.
• Enhanced delivery strategies show potential for improving VHH-based therapeutics for Alzheimer's disease.
• Further research will evaluate the therapeutic potential of these novel anti-Aβ VHH immunotherapies.