AAV Capsid Targeting Peptide for Blood-Brain Barrier Crossing
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Solution Overview
Problem
Current gene therapy delivery methods, particularly for central nervous system (CNS) disorders, face challenges due to the limited ability of Adeno-Associated Virus (AAV) vectors to cross the Blood-Brain Barrier (BBB) and effectively transduce deep brain cells, restricting the treatment of CNS disorders.
Innovation Solution
Development of recombinant AAV vectors with an exogenous targeting peptide sequence, such as Y-X-X″-GNPA-X″″-RYFD-X″″, inserted into the hypervariable region of the AAV capsid, which enhances BBB targeting and transduction efficiency in the CNS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AAV vectors are used for gene therapy delivery to the CNS, then the vectors can be stably expressed long-term from a non-integrating genome, but the vectors are limited in their ability to cross the Blood-Brain Barrier and transduce deep brain cells
Solution Approach 1:
The patent applies local quality by introducing a specific targeting peptide sequence (Y-X-X''-GNPA-X''''-RYFD-X''''') into a specific location (hypervariable loop 8) of the AAV capsid structure. This localized modification enables the vector to specifically interact with Ly6a receptors on brain vasculature, achieving both reliable stable expression and improved transduction efficiency for deep brain cells simultaneously.
Solution Approach 2:
The patent changes the capsid parameter by modifying the amino acid sequence at a specific position (hypervariable loop 8) to incorporate the targeting peptide. This parameter change in the capsid structure fundamentally alters the vector's tropism, enabling it to cross the BBB efficiently while maintaining stable long-term expression characteristics.
2Ease of operation
If direct delivery of AAV vectors is performed by injecting into cerebrospinal fluid, then delivery to the CNS is possible, but only 1% or less of brain cells are transduced with most transduction concentrated on cells in direct contact with CSF
Solution Approach 1:
The patent uses an intermediary mechanism by introducing a targeting peptide that mediates interaction with Ly6a receptors on the blood vasculature. This intermediary binding enables the vector to be transported across the BBB through the vascular system, dramatically improving transduction efficiency from 1% to over 50% of brain cells without requiring direct CSF injection.
Solution Approach 2:
The patent transitions from a direct CSF injection approach (one-dimensional delivery) to a vascular system-mediated delivery approach (multi-dimensional delivery through blood vessels). This dimensional change allows the vector to reach cells throughout the entire brain volume, including deep brain structures, rather than being limited to cells in direct contact with CSF.
3Object-affected harmful factors
If the Blood Brain Barrier is used to protect brain cells from the circulatory system, then cell protection is achieved, but large molecules like viral vectors and proteins are blocked from reaching brain cells
Solution Approach 1:
The patent converts the harmful barrier function of the BBB into a beneficial selective transport mechanism. By designing the capsid with a targeting peptide that specifically binds to Ly6a receptors on the BBB, the vector exploits the barrier's selective permeability properties to achieve efficient transport. The BBB's restriction of large molecules is overcome through specific receptor-mediated endocytosis, transforming the barrier from a complete block into a selective gateway.
Data Source
AI summary
Provided herein are compositions including brain-capillary binding and/or blood-brain barrier crossing (BBB) tissue-targeting peptides linked thereto or inserted in a targeting protein of a recombinant vector having at least one exogenous peptide comprising an amino acid sequence of Y-G/A/R/K-Y/H-GNPA-T/R/H-RYFD-V/K. Compositions providing such conjugates, targeting peptides, or recombinant vectors having a mutant capsid or envelope protein are provided as are uses thereof.