Alpha4beta7 Peptide Dimer Antagonists Selectivity
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Solution Overview
Problem
Current integrin antagonists lack selectivity for α4β7 integrin while interfering with α4β1 integrin-ligand interactions, leading to dangerous side effects in treating gastrointestinal autoimmune diseases.
Innovation Solution
Development of α4β7 antagonist dimer peptides with cyclized structures linked by C- or N-terminus via a linking moiety, providing increased stability, specificity, and potency, specifically targeting α4β7 integrin with minimal effect on α4β1 integrin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monoclonal antibodies or small molecule antagonists are used to inhibit integrin-ligand interactions, then anti-inflammatory effects are achieved, but selectivity for α4β7 is lost and α4β1 is also affected causing side effects
Solution Approach 1:
The invention divides the integrin antagonist function into two distinct parts: a cyclic peptide component that provides α4β7 specificity and a dimerization component that enhances potency. The cyclic peptide contains specific amino acid sequences (e.g., Cys-Pro-Xaa-Yaa-Zaa-Gly-Leu) that selectively recognize α4β7 epitopes, while the dimerization via linkers (e.g., PEG, DIG, IDA) amplifies the blocking effect. This segmentation allows selective inhibition of α4β7-MAdCAM interactions without affecting α4β1-VCAM binding.
Solution Approach 2:
The cyclic peptide structure introduces local structural constraints through disulfide bonds and specific amino acid configurations that create a three-dimensional conformation selectively recognized by α4β7. The cyclization (e.g., head-to-tail or side-chain to backbone) creates a rigid local structure with specific spatial arrangement of key residues (e.g., Arg, Gln, Asn) that match the α4β7 binding pocket, while leaving other regions flexible for dimerization. This local quality differentiation enables selective binding to α4β7 over α4β1.
2Ease of operation
If peptide antagonists are designed for oral administration, then patient compliance improves, but peptide stability in gastrointestinal tract decreases
Solution Approach 1:
The peptide is pre-modified with cyclization (disulfide bonds, amide bonds, or other crosslinks) and dimerization before administration. This preliminary structural reinforcement protects the peptide from gastrointestinal proteases and harsh pH conditions. The cyclic structure reduces conformational flexibility that would otherwise make the peptide susceptible to enzymatic degradation, while the dimerization further stabilizes the structure. These modifications are performed in advance (preliminarily) to ensure stability upon oral administration.
Solution Approach 2:
The invention creates a composite peptide structure combining multiple stabilizing elements: cyclic constraints (disulfide bridges, amide bonds), dimerization linkers (PEG, DIG, IDA), and specific amino acid compositions. This composite structure integrates protective features at multiple levels - the cyclic core provides resistance to proteolysis, while the dimeric architecture with stable linkers enhances overall structural integrity. The composite nature allows the peptide to withstand gastrointestinal conditions while maintaining biological 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 α4β7 antagonist dimer peptides effectively inhibit α4β7 integrin activity, reducing inflammation in gastrointestinal autoimmune diseases with enhanced stability and selectivity, minimizing side effects associated with α4β1 integrin interference.
Implementation Method 1
Each subunit of the present invention further comprises two natural or unnatural amino acids that are capable of bridging to form a cyclized structure... through at least one of a disulfide salt bridge
Implementation Method 2
compounds of the present invention comprise dimerized peptides, each subunit of the dimer forming a cyclized structure through at least one of a disulfide salt bridge, an amide bond, or an equivalent connection
Data Source
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AI summary
The invention relates to disulfide-rich dimer molecules which inhibit binding of α4ß7 to the mucosal addressin cell adhesion molecule (MAdCAM) in vivo, and show high selectivity against α4ß1 binding.