Annexin A2 Mediator Enhances Factor H Binding to Renal Cells
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Solution Overview
Problem
Uncontrolled activation of the alternative complement pathway contributes to tissue injury in conditions like renal ischemia/reperfusion and ischemic acute kidney injury, with factor H having limited efficacy in preventing complement activation on renal tubules due to insufficient binding affinity.
Innovation Solution
Administering compositions such as annexin A2 or fusion proteins with anti-annexin A2 antibodies fused to complement inhibitors like DAF, factor H, MCP, CD59, CR1, or mouse Crry protein to modulate alternative complement activity, either inhibiting or stimulating it, by selectively binding to annexin A2 expressed in the kidneys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If factor H is administered to prevent complement activation on renal tubules, then complement-mediated tissue injury is reduced, but the binding affinity of factor H to renal epithelial cells is insufficient, limiting its efficacy
Solution Approach 1:
The patent uses annexin A2 as an intermediary molecule that binds to both factor H and renal epithelial cells. By expressing annexin A2 on the surface of renal tubular epithelial cells, the system creates a bridging mechanism that enhances the binding affinity between factor H and the target cells, thereby improving the reliability of complement inhibition without directly modifying factor H itself
Solution Approach 2:
The patent modifies the binding parameters of the factor H-renal epithelial cell interaction by introducing annexin A2 binding sites. This changes the binding affinity parameter from insufficient to adequate, allowing factor H to effectively bind to renal tubules and exert its complement-inhibiting function. The approach alters the physical-chemical parameters of the interaction rather than changing the biological function of factor H
2Object-affected harmful factors
If uncontrolled alternative pathway activation occurs, then complement amplification and tissue injury are promoted, but controlling the pathway requires sufficient binding of regulatory proteins to target surfaces
Solution Approach 1:
Annexin A2 serves as a mediator that connects factor H (a regulatory protein) to renal epithelial cell surfaces. This intermediary mechanism ensures reliable control of the alternative complement pathway by enabling regulatory proteins to effectively bind to and control complement activation on target surfaces, preventing uncontrolled amplification and tissue injury
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 approach effectively limits or enhances alternative complement-mediated renal injury by improving the binding affinity of factor H to renal epithelial cells, thereby controlling complement activation and reducing tissue damage.
Implementation Method 1
We demonstrate herein that factor H binds to annexin A2 in post-ischemic kidneys
Implementation Method 2
C3 convertase (C3bBb) and/or serve as cofactors for the cleavage of C3 by factor I, forming iC3b
Implementation Method 3
The CRPs dissociate the alternative pathway C3 convertase (C3bBb) and/or serve as cofactors for the cleavage of C3 by factor I
Data Source
AI summary
Provided herein are compositions, including pharmaceutical compositions, and methods for modulating, i.e., stimulating or inhibiting, activity of the alternative complement pathway, and methods of identifying factor H-binding proteins.