GH-Loop Peptide Insertion in AAV Capsids for Retinal Targeting
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Solution Overview
Problem
Existing adeno-associated virus (AAV) vectors face challenges in efficiently targeting and infecting retinal cells, particularly the inner nuclear layer, outer nuclear layer, photoreceptor layer, ganglion cell layer, and retinal pigment epithelium, limiting their effectiveness in treating ocular diseases.
Innovation Solution
Development of recombinant AAV virions with altered capsid proteins containing a heterologous peptide insertion in a surface-accessible region, such as the GH loop, enhancing infectivity and localization to these retinal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type AAV capsid is used, then the virus maintains structural stability and basic infectivity, but the localization to retinal layers is insufficient and infectivity is limited
Solution Approach 1:
The patent applies local quality by introducing a heterologous peptide insertion specifically in the GH loop region of the capsid protein, which is a surface-accessible area that contacts retinal cells. This localized modification enhances the virus's ability to target and localize to specific retinal layers (inner nuclear layer, outer nuclear layer, photoreceptor layer, ganglion cell layer, and retinal pigment epithelium) without altering the overall capsid structure or requiring complete redesign of the viral particle.
Solution Approach 2:
The patent employs parameter changes by modifying the capsid protein sequence at a specific location (GH loop) through peptide insertion. This changes the biochemical and biophysical parameters of the capsid surface, thereby altering its interaction with retinal cell receptors and improving both infectivity and localization efficiency in retinal tissues.
2Reliability
If capsid protein is modified to increase infectivity, then retinal cell targeting is improved, but the capsid structure may be compromised
Solution Approach 1:
The modification is localized to a specific surface region (GH loop) rather than disrupting the entire capsid structure. The heterologous peptide insertion is positioned in a surface-accessible area that maintains the overall capsid integrity while providing enhanced interaction capabilities with retinal cells, thus improving infectivity without compromising structural stability.
Solution Approach 2:
The heterologous peptide acts as an intermediary element between the capsid and retinal cell receptors. This peptide insertion serves as a mediating structure that facilitates viral entry and localization to retinal layers while the rest of the capsid maintains its protective function, effectively decoupling the infectivity enhancement from structural compromise.
Data Source
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AI summary
The present disclosure provides adeno-associated virus (AAV) virions with altered capsid protein, where the AAV virions exhibit greater infectivity of retinal cells compared to wild-type AAV. The present disclosure further provides methods of delivering a gene product to a retinal cell in an individual, and methods of treating ocular disease.