VHH Albumin Binding to Extend Therapeutic Protein Half-Life
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Solution Overview
Problem
Therapeutic proteins with short plasma half-lives due to small size or lack of FcRn binding face challenges in maintaining effective plasma concentrations, necessitating a solution to prolong their duration in circulation.
Innovation Solution
Development of albumin-binding polypeptides, specifically VHH domains with defined CDR sequences, to enhance the half-life of therapeutic molecules by binding to albumin, thereby avoiding renal filtration and micropinocytosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If therapeutic proteins are made small for better tissue penetration, then they can reach target sites more effectively, but their plasma half-life becomes short due to rapid renal filtration
Solution Approach 1:
The patent combines a small therapeutic protein with a VHH domain that binds to albumin, creating a fusion protein. This merging allows the small therapeutic protein to associate with the large albumin carrier (66 kDa), which protects it from renal filtration. The fusion protein thus achieves both small size benefits for tissue penetration and extended plasma half-life through albumin binding.
Solution Approach 2:
The VHH domain acts as an intermediary between the small therapeutic protein and albumin. This intermediary component specifically binds to albumin, serving as a bridge that connects the small therapeutic molecule to the large plasma protein carrier, thereby extending circulation time without compromising the therapeutic protein's functionality.
2Device complexity
If therapeutic proteins lack FcRn binding capability, then they can be simpler in structure, but they are rapidly cleared through micropinocytosis
Solution Approach 1:
The patent merges the simple therapeutic protein structure with a VHH domain that specifically binds to the FcRn recycling pathway. This combination allows the protein to utilize the FcRn-mediated recycling mechanism without requiring complex IgG structures, thus maintaining structural simplicity while achieving extended plasma half-life through FcRn binding.
3Duration of action of moving object
If albumin-binding VHH domains are fused to therapeutic proteins, then plasma half-life is prolonged, but the molecular size increases
Solution Approach 1:
The VHH domain is designed to bind specifically to a localized region on albumin (domain 1 or 2), rather than requiring interaction with the entire albumin structure. This localized binding approach allows for efficient albumin association with minimal increase in overall molecular size, as the VHH domain interacts with a specific epitope rather than the whole protein.
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 albumin-binding VHH domains significantly prolong the plasma half-life of therapeutic proteins, allowing for precise control of drug concentrations, reduced toxicity, and lower dosing frequencies.
Implementation Method 1
their ability to recycle from endothelial micropinocytosis through pH dependent binding to the neonatal Fc receptor (FcRn)
Data Source
AI summary
Provided herein are VHH-containing polypeptides that bind albumin. Uses of the VHH-containing polypeptides are also provided.