Engineered AgRP Polypeptides for Appetite Stimulation
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Solution Overview
Problem
Current technologies fail to effectively stimulate appetite and treat conditions like cachexia, which involves negative energy balance, as they do not adequately utilize the non-receptor binding core segments of the Agouti-Related Protein (AgRP) for enhanced feeding and weight gain.
Innovation Solution
Development of synthetic, engineered polypeptides with increased positive charge, specifically targeting the N-terminal extension and C-terminal loop of AgRP, which are administered to stimulate appetite and enhance feeding when introduced into the CNS, leading to significantly increased food intake and weight gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wild-type AgRP is used to stimulate appetite, then feeding is stimulated, but the feeding stimulation is insufficient compared to engineered polypeptides with increased positive charge
Solution Approach 1:
The patent applies parameter changes by modifying the charge characteristics of AgRP polypeptides. Engineered polypeptides with increased positive charge (such as AgRP-4K with four additional lysine residues) demonstrate significantly enhanced feeding stimulation compared to wild-type AgRP, showing that altering electrostatic parameters can dramatically improve orexigenic efficacy
Solution Approach 2:
The patent creates composite polypeptide structures by combining the AgRP receptor-binding core with optimized N-terminal and C-terminal regions. These engineered constructs integrate multiple functional elements including the essential MC3R/MC4R binding domain plus modified regions that enhance stability and potency, resulting in superior appetite-stimulating activity
2Duration of action of moving object
If only the receptor binding core of AgRP is utilized, then the structure is simpler, but the feeding response is shorter duration and less potent
Solution Approach 1:
The patent segments the AgRP polypeptide into distinct functional regions: the N-terminal region (residues 83-86), the central receptor-binding core (residues 87-120), and the C-terminal region (residues 121-132). This segmentation allows identification that while the core is essential for receptor binding, the N-terminal and C-terminal segments contribute to prolonged duration of action and enhanced potency
Solution Approach 2:
The engineered polypeptides achieve multi-functionality by combining receptor binding activity (core function) with extended duration and enhanced potency (additional functions provided by N-terminal and C-terminal regions). The full-length and engineered constructs perform multiple roles: binding to MC3R/MC4R receptors, resisting degradation, and providing sustained orexigenic signaling
3Productivity
If engineered polypeptides with increased positive charge are used, then feeding stimulation is nearly doubled, but the polypeptide sequence becomes more complex and non-natural
Solution Approach 1:
The patent systematically modifies amino acid sequences to increase positive charge, specifically introducing additional lysine residues (e.g., AgRP-2K with two extra lysines, AgRP-4K with four extra lysines). These parameter changes in charge density directly correlate with enhanced feeding stimulation, providing a rational design approach that balances manufacturability with improved efficacy
Data Source
AI summary
An engineered polypeptide comprising an AgRP analog with increased basic residues compared to the wild type polypeptide, wherein the polypeptide, when introduced into the CNS of a mammal, stimulates appetite.