Segmented Polypeptide for Deep Cartilage Penetration
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Solution Overview
Problem
Conventional antibodies face challenges in targeting antigens in deep cartilage tissue due to high molecular weight and difficulty in avoiding adverse reactions, as they can distribute to normal tissues through blood flow after protease cleavage, and there are limited cancer-specific antigens expressed in normal tissues.
Innovation Solution
Development of polypeptides with an antigen binding domain and a carrying moiety that inhibits antigen binding activity, allowing for deeper penetration and longer retention in cartilage tissue, using protease cleavage to restore antigen binding activity in disease tissues while minimizing systemic distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional antibodies are used to target antigens in cartilage tissue, then antigen binding activity is achieved, but penetration depth into cartilage tissue is limited due to high molecular weight
Solution Approach 1:
The antibody molecule is divided into two separate components: a carrying moiety (such as Fc region or antibody fragment) and an antigen binding domain (such as scFv, Fab, or single-domain antibody). This segmentation allows the antigen binding domain to penetrate deep into cartilage tissue due to its smaller size, while the carrying moiety remains in circulation to provide half-life extension and can be selectively activated by protease cleavage in the target tissue.
2Reliability
If protease cleavage is used to activate antigen binding activity, then therapeutic effect is enhanced, but distribution to normal tissues through blood flow causes adverse reactions
Solution Approach 1:
The polypeptide structure is designed with different functional regions having distinct properties: the carrying moiety has long plasma half-life for systemic circulation, while the antigen binding domain has short plasma half-life to minimize systemic exposure. Protease cleavage sites are strategically positioned to enable localized activation only in the target cartilage tissue where specific proteases (such as MMPs or ADAMTS) are overexpressed, thereby achieving local therapeutic effect while minimizing systemic adverse reactions.
Solution Approach 2:
Proteases expressed specifically in the target cartilage tissue (such as MMP-13 or ADAMTS-5) serve as intermediaries that selectively cleave the linker region of the polypeptide. This intermediary mechanism ensures that antigen binding activity is restored only in the presence of these tissue-specific proteases, providing spatial selectivity and preventing systemic activation that would lead to adverse reactions in normal tissues.
3Reliability
If cancer-specific antigens are targeted, then cytotoxic activity against cancer cells is achieved, but limited availability of such antigens restricts therapeutic application
Solution Approach 1:
The invention employs a universal platform architecture where the antigen binding domain can be exchanged to target different antigens. The carrying moiety and linker design remain consistent, allowing the same structural framework to be applied to various therapeutic targets including cartilage-specific antigens (aggrecan, collagen type II), cancer antigens, and other disease markers. This multi-functionality expands the versatility of the therapeutic approach beyond limited cancer-specific applications.
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 suppress Aggrecan proteolytic cleavage and penetrate deeply into cartilage tissue, reducing adverse reactions and enhancing drug delivery and retention, making them useful for treating osteoarthritis and other cartilage-related diseases.
Implementation Method 1
The polypeptides effectively suppress Aggrecan proteolytic cleavage
Implementation Method 2
using protease cleavage to restore antigen binding activity in disease tissues
Data Source
AI summary
The present invention provides a polypeptide comprising an antigen binding domain which binds to an antigen present in cartilage tissue, and also provides use of the polypeptide. The polypeptide of the invention is useful for penetrating and/or retaining a desired substance in the cartilage tissue for a long period. The present invention further relates to a polypeptide comprising (i) an antigen binding domain which binds to a molecule in a cartilage tissue, and (ii) a carrying moiety having an inhibiting domain that inhibits the antigen binding activity of the antigen binding domain, and having a longer half-life than that of the antigen binding domain existing alone, and a pharmaceutical composition comprising the polypeptide. The present invention further relates to methods for producing and screening for the polypeptide.