Dimeric Peptide Inhibitors for PSD-95 Binding
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Solution Overview
Problem
Existing PSD-95 inhibitors, such as nerinetide, suffer from low affinity to the target PSD-95 and are not effective when administered with thrombolytic agents like tPA, limiting their neuroprotective potential in conditions like acute ischemic stroke and subarachnoid hemorrhage.
Innovation Solution
Development of novel dimeric compounds comprising specific peptides linked to Cell Penetrating Peptides (CPPs) via linkers, which exhibit high affinity for PSD-95 PDZ domains, enhance cellular uptake, and are stable against plasmin, allowing simultaneous binding to PDZ1 and PDZ2 domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nerinetide is used as a PSD-95 inhibitor, then it can bind to PSD-95, but it has low affinity (K i values of 5-10 μM) and is cleaved by plasmin when administered with tPA
Solution Approach 1:
The invention divides the single peptide binding site into two separate binding sites (PDZ1 and PDZ2) and uses a dimeric structure with two peptide copies to bind both sites simultaneously. This segmentation approach increases affinity by 500-1000-fold (K i values of 4.6 and 9.5 nM) while the rigid dimeric structure protects against plasmin cleavage that affects monomeric nerinetide
Solution Approach 2:
The invention creates a composite dimeric structure combining two peptide moieties (P1 and P2) linked by a flexible linker. This composite structure provides both high affinity binding to PSD-95 PDZ domains and resistance to plasmin cleavage, resolving the contradiction between binding reliability and stability against harmful factors
2Adaptability or versatility
If nerinetide is administered with tPA for ischemic stroke treatment, then thrombolytic therapy is provided, but nerinetide is cleaved by plasmin generated from tPA
Solution Approach 1:
The monomeric nerinetide structure is segmented into a dimeric configuration where two peptide copies are linked together. This segmentation creates a rigid structure that resists plasmin cleavage while maintaining compatibility with tPA administration for ischemic stroke treatment
Solution Approach 2:
The invention changes the structural parameter from monomeric to dimeric configuration, which fundamentally alters the drug's stability profile. The dimeric structure increases resistance to plasmin cleavage while maintaining therapeutic compatibility with thrombolytic agents
3Reliability
If monomeric nerinetide is used, then it can inhibit PSD-95, but it has poor cellular uptake and low neuroprotective efficacy
Solution Approach 1:
The monomeric structure is segmented into a dimeric structure with two peptide copies. This segmentation increases molecular size and rigidity, which improves cellular uptake and membrane penetration, thereby enhancing neuroprotective efficacy in ischemic stroke models
Solution Approach 2:
The dimeric composite structure combines two peptide moieties that work synergistically to improve cellular uptake and membrane penetration. This composite approach resolves the contradiction between neuroprotective efficacy and ease of cellular uptake by creating a structure that is both potent and penetrant
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 novel compounds demonstrate improved neuroprotective effects in ischemic stroke models, with enhanced cellular uptake and stability, enabling effective treatment of excitotoxic-related diseases while being compatible with standard of care therapies.
Implementation Method 1
a Cell Penetrating Peptide (CPP) selected from the group consisting of: i. a poly-L-arginine peptide (poly-Arg) consisting of 3 to 9 L-arginine residues
Implementation Method 2
PSD-95 is a scaffolding protein in neuronal synapses that interacts with N-methyl-D-aspartate (NMDA) receptors (Kornau et al. 1995) and neuronal nitric oxide synthase (nNOS) through its PSD-95/Discs-large/ZO-1 (PDZ) domains
Data Source
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AI summary
The present invention relates to compounds capable of binding to the PDZ domains of PSD-95 and their medical use as inhibitors of protein-protein interaction mediated by PSD-95.