C3b-Binding CR1 Polypeptides for Bruch's Membrane Penetration
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Solution Overview
Problem
Current treatments for complement-related diseases, particularly age-related macular degeneration (AMD), are ineffective as complement-regulating antibodies cannot reach the target areas within the eye, such as Bruch's membrane and the choriocapillaris, due to their inability to traverse these structures, and existing therapies do not address the underlying complement activation that leads to disease progression.
Innovation Solution
Development of soluble, truncated polypeptides derived from the complement factor I cofactor CR1, which can bind to C3b and act as efficient cofactors for complement regulation, allowing them to traverse Bruch's membrane and reach affected sites, thereby modulating complement activation locally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complement-regulating antibodies are used to treat AMD, then complement activation can be regulated, but the antibodies cannot reach the target areas within the eye due to inability to traverse Bruch's membrane and choriocapillaris
Solution Approach 1:
The invention extracts the essential functional domains (CCP 8-10 and CCP 15-17) from the full-length CR1 protein to create truncated polypeptides. These extracted domains retain the ability to bind C3b and act as cofactors for Factor I-mediated cleavage, while being small enough to traverse Bruch's membrane and reach the choriocapillaris, thereby resolving the contradiction between maintaining complement regulation function and achieving target site delivery
Solution Approach 2:
The CR1 protein is segmented into functional domains, specifically isolating the C3b-binding CCP domains (8-10 and 15-17) from the rest of the protein structure. This segmentation allows the creation of minimal functional units that can penetrate ocular barriers while preserving the essential complement regulatory activity, solving the delivery efficacy contradiction
2Reliability
If full-length CR1 or large proteins are used, then complement regulation function is maintained, but they cannot traverse Bruch's membrane to reach the choriocapillaris
Solution Approach 1:
The essential C3b-binding CCP domains (8-10 and 15-17) are extracted from the full-length CR1 protein, creating truncated polypeptides that are small enough to traverse Bruch's membrane while retaining complement regulatory function through C3b binding and Factor I cofactor activity
Solution Approach 2:
The invention concentrates the essential functional properties (C3b binding and Factor I cofactor activity) into specific local domains (CCP 8-10 and CCP 15-17), creating polypeptides that have the necessary local quality for complement regulation without the bulk of the full-length protein, enabling them to reach the target site
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The polypeptides effectively regulate complement activation at the site of disease, providing targeted therapy without disrupting systemic complement regulation, offering potential treatment or prevention of AMD and other complement-related conditions.
Implementation Method 1
a polypeptide which is capable of binding C3b, the polypeptide comprising an amino acid sequence having at least 85% identity to SEQ ID NO:4
Data Source
AI summary
Polypeptides comprising a C3b binding region are disclosed, as well as nucleic acids and vectors encoding such polypeptides, and cells and compositions comprising such polypeptides. Also disclosed arc uses and methods using the polypeptides for treating and preventing diseases and conditions.