VNAR Polypeptides Targeting TfR-1 for BBB Delivery
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Solution Overview
Problem
Current technologies face challenges in delivering therapeutic and diagnostic agents across biological barriers such as the blood-brain barrier (BBB) and the gastrointestinal (GI) tract, with existing molecules often requiring high doses and having adverse side effects.
Innovation Solution
Development of new, isolated Type II VNAR polypeptides that specifically bind to human transferrin receptor-1 (TfR-1) without interfering with transferrin binding or transport, allowing for targeted delivery of therapeutic and diagnostic agents across various biological barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monoclonal antibodies are used to target TfR-1 for BBB delivery, then species-specific binding is achieved, but cross-reactivity across primate species is limited and high doses are required
Solution Approach 1:
The VNAR polypeptides are designed to bind to conserved epitopes on the TfR-1 receptor that are present across multiple primate species (human, chimpanzee, gorilla, orangutan, rhesus macaque). This universal binding capability allows a single VNAR construct to function across different species, eliminating the need for species-specific optimization while maintaining reliable binding affinity.
2Productivity
If high doses of therapeutic agents are administered to achieve effective BBB penetration, then delivery efficiency is improved, but adverse side effects increase
Solution Approach 1:
The invention changes the binding affinity parameter of the targeting molecule by using VNAR polypeptides with optimized complementarity determining regions (CDRs) that exhibit high nanomolar affinity for TfR-1. This enhanced binding strength allows effective BBB penetration at lower doses, directly reducing the relationship between dose and delivery efficiency while minimizing exposure-related side effects.
3Speed
If VNAR polypeptides are designed to bind with high affinity to TfR-1, then BBB uptake efficiency is improved, but interference with endogenous transferrin binding may occur
Solution Approach 1:
The VNAR polypeptides are engineered to bind to specific local epitopes on the TfR-1 receptor extracellular domain that are distinct from the transferrin binding site. By targeting a different local region of the receptor, the VNAR maintains high affinity binding for efficient BBB uptake while preserving the integrity of endogenous transferrin-receptor interactions and normal iron transport function.
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 VNAR polypeptides demonstrate efficient uptake across the BBB and other biological barriers, enabling effective delivery of therapeutic and diagnostic agents at lower doses with reduced side effects, thereby addressing the limitations of current technologies.
Implementation Method 1
VNAR polypeptides that specifically bind to human transferrin receptor-1 (TfR-1) without interfering with transferrin binding or transport
Data Source
AI summary
The present invention relates to a high affinity, VNAR polypeptide cross reactive with primate transferrin receptors (“TfR”). This TfR-specific VNAR polypeptide was obtained by screening semisynthetic VNAR phage display libraries against recombinant human TfR-1. The VNAR polypeptides of the invention can be used alone or as a component in conjugates that target the transferrin/transferrin receptor transport system. The invention further includes use of this VNAR, its conjugates and other derivatives in diagnostic and therapeutic methods, e.g., to diagnose, treat and/or prevent a pathological condition, disorder or disease in which it is beneficial to deliver a heterologous biomolecule across the blood brain barrier or other membrane systems. This TfR-specific VNAR polypeptide can also be used to target other biological barriers such the intestines, the placenta or aberrant cells overexpressing TfR-1, for therapeutic benefit in treatment of certain cancer cells and tumors of various tissue types. Deimmunized VNAR scaffolds are also provided.