Modified u-PA Polypeptides for Selective C3 Cleavage
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Solution Overview
Problem
Current therapeutics for inhibiting complement activation, such as small molecules and antibodies, have limitations in efficacy and safety, particularly for chronic diseases, necessitating the development of alternative treatments that can effectively target and inhibit the complement cascade.
Innovation Solution
Modified urokinase-type plasminogen activator (u-PA) polypeptides with specific amino acid modifications, including insertions, deletions, and replacements, are designed to cleave complement protein C3, thereby inhibiting complement activation, with enhanced specificity and activity compared to wild-type u-PA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small molecule therapeutics are used to inhibit complement activation, then complement inhibition is achieved, but half-life is short and continuous infusion is required
Solution Approach 1:
The patent changes the molecular parameters of the therapeutic agent by using modified u-PA polypeptides with specific amino acid modifications (e.g., at positions 35, 37, 40, 41, 60, 97, 99) that alter the protein's pharmacokinetic properties. These modifications extend half-life while maintaining complement inhibition efficacy, eliminating the need for continuous infusion required by small molecule therapeutics.
Solution Approach 2:
The invention creates a composite therapeutic protein by fusing u-PA polypeptide with complement regulatory domains or conjugating to carrier proteins. This composite structure combines the complement inhibition activity of u-PA with the extended half-life characteristics of the fusion partner, resolving the contradiction between efficacy and duration of action.
2Reliability
If therapeutic antibodies are used to target complement activation, then complement inhibition is achieved, but immune response occurs leading to complications
Solution Approach 1:
The patent employs engineered u-PA polypeptides with modified amino acid sequences that reduce immunogenicity. By using humanized or chimeric sequences with specific modifications (e.g., at positions 35, 37, 40, 41, 60, 97, 99), the therapeutic elicits minimal immune response compared to conventional antibodies, reducing complications while maintaining complement inhibition efficacy.
Solution Approach 2:
The invention applies local quality modification by making specific amino acid changes only in the u-PA polypeptide's complement binding domain while maintaining other regions. This localized modification reduces immunogenicity at the immune recognition level without compromising the complement inhibition function, thereby resolving the contradiction between efficacy and harmful immune responses.
3Productivity
If wild-type u-PA is used, then some complement activity is observed, but specificity for C3 is insufficient
Solution Approach 1:
The patent applies local quality modification by making specific amino acid changes only in the u-PA polypeptide's complement binding domain while maintaining other regions. This localized modification reduces immunogenicity at the immune recognition level without compromising the complement inhibition function, thereby resolving the contradiction between efficacy and harmful immune responses.
Solution Approach 2:
The invention changes the sequence parameters of u-PA at specific positions (35, 37, 40, 41, 60, 97, 99) to enhance C3 binding affinity and specificity. These parameter modifications result in polypeptides with increased productivity in inhibiting complement activation through enhanced C3 cleavage activity.
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 modified u-PA polypeptides demonstrate increased activity and specificity for C3, achieving significant inhibition of complement activation, which can treat a range of diseases and conditions mediated by complement, including AMD, DGF, ischemic disorders, autoimmune diseases, and inflammatory diseases, with reduced activity on native substrates like plasminogen.
Implementation Method 1
Modified urokinase-type plasminogen activator (u-PA) polypeptides... cleave complement protein C3... whereby the modified u-PA polypeptides inhibit complement activation
Data Source
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AI summary
Provided are u-PA polypeptides and fusion proteins containing the u-PA polypeptides. The u-PA polypeptides are modified to have altered activity and/or specificity so that they cleave a complement protein, such as complement protein C3, to thereby inhibit complement activation. The modified u-PA polypeptides and fusion proteins that inhibit complement activation can be used for treatment of diseases and conditions that are mediated by complement activation, or in which complement activation plays a role. These disorders include ischemic and reperfusion disorders, including myocardial infarction and stroke, sepsis, autoimmune diseases, diabetic retinopathies, age-related macular degeneration, transplanted organ rejection, inflammatory diseases and diseases with an inflammatory component.