Peptide Derivative for Pancreatic Beta-Cell Imaging
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Solution Overview
Problem
Current molecular probes for imaging pancreatic β-cells are not specific enough for clear imaging and quantification, leading to unsatisfactory results in diagnosing and preventing type-II diabetes, as they do not accumulate sufficiently in pancreatic islets and have poor contrast with surrounding tissues.
Innovation Solution
A peptide derivative represented by a specific general formula that accumulates specifically in pancreatic β-cells, particularly GLP-1R, with improved blood clearance and labeling efficiency, allowing for effective imaging using PET or SPECT, and is produced using a labeling precursor with enhanced labeling yields and reduced labeling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional molecular probes are used for imaging pancreatic β-cells, then imaging can be performed, but the probes do not accumulate sufficiently in pancreatic islets and have poor contrast with surrounding tissues
Solution Approach 1:
The patent modifies the chemical structure of exendin-4 by introducing a cyclic constraint between Lys12 and Lys27 residues, and by N-terminal modification with various groups (acetyl, benzoyl, pivaloyl, etc.). These structural parameter changes enhance the probe's specificity for GLP-1R in pancreatic β-cells while improving blood clearance, thereby achieving both high measurement precision and reliability in imaging
Solution Approach 2:
The patent creates composite peptide structures by combining modified exendin-4 sequences with specific N-terminal groups and cyclic constraints. These composite structures exhibit improved pharmacokinetic properties including enhanced specificity for pancreatic islet accumulation and better blood clearance, resolving the contradiction between imaging clarity and accumulation reliability
2Measurement precision
If peptide derivatives are used for imaging, then they can target GLP-1R in pancreatic β-cells, but the production process requires efficient labeling with radionuclides
Solution Approach 1:
The patent introduces pre-installed functional groups (amine, carboxyl, hydroxyl) at specific positions in the peptide structure that can serve as labeling sites. The N-terminal modifications and cyclic structures are designed in advance to facilitate subsequent radionuclide labeling, thereby maintaining high targeting specificity while simplifying the manufacturing process and reducing labeling time
3Loss of time
If early diagnosis of diabetes is achieved through imaging, then intervention can be made before pancreatic islet damage progresses, but the probes must have high specificity to detect early changes
Solution Approach 1:
The patent employs specific structural modifications including cyclic constraints and N-terminal groups that enhance the probe's affinity and specificity for GLP-1R. These parameter changes enable the probe to detect even subtle reductions in pancreatic β-cell mass or function at very early stages, allowing timely diagnosis and intervention while maintaining high measurement precision
Data Source
AI summary
A new peptide derivative is provided. The peptide derivative is represented by the following general formula (I),where polypeptide ExP is polypeptide that contains completely or partially the amino acid sequence of exendin-4, and a -L-Z group represents a group represented by the following formula (II) that is bonded to an amino acid side chain of or the α-amino group at the N-terminus of the polypeptide ExP,