Cyclic Peptide Epitopes Inducing Autophagy via Cell Penetration
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Solution Overview
Problem
Current peptide drugs face challenges in effectively inducing autophagy due to poor membrane penetration and cytotoxicity, limiting their therapeutic potential for conditions like neurodegenerative disorders and infectious diseases.
Innovation Solution
Development of cyclic peptides and small-molecule mimics that are cell-penetrating, specifically designed to induce autophagy by stabilizing key residues and structures, such as the DD5-o peptide, which uses thiol bis-alkylation chemistry to introduce diverse conformations and enhance cellular uptake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear peptides are used to induce autophagy, then autophagy induction capability is improved, but membrane penetration and cellular uptake deteriorate
Solution Approach 1:
The patent applies parameter changes by cyclizing linear peptides into cyclic structures, which fundamentally alters the conformational parameters and structural rigidity of the peptide. This cyclic structure enables the peptide to maintain a stable bioactive conformation that can effectively induce autophagy while simultaneously improving membrane penetration capabilities, thus resolving the technical contradiction between autophagy induction capability and membrane penetration.
Solution Approach 2:
The patent employs composite materials by combining cyclic peptide structures with cell-penetrating sequences (such as Tat sequences) or lipid modifications. This creates a composite molecular architecture that integrates the autophagy-inducing functionality of the cyclic peptide with the membrane-translocating properties of the cell-penetrating component, thereby achieving both effective autophagy induction and improved cellular uptake.
2Ease of operation
If Tat sequence is added to enhance cell penetration, then membrane penetration is improved, but cytotoxicity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the length, composition, and charge density of cell-penetrating sequences when combined with cyclic peptides. By carefully tuning these parameters, the patent achieves sufficient membrane penetration while reducing the excessive positive charge that causes cytotoxicity. This includes using shorter Tat sequences, modifying amino acid composition, or adjusting the N-terminal cap structure to balance penetration efficiency with cellular safety.
Solution Approach 2:
The patent applies local quality by strategically placing cell-penetrating sequences only at specific locations (such as the N-terminus) of the cyclic peptide, rather than uniformly distributing charged residues throughout the structure. This localized modification enables membrane penetration at the interface while maintaining a neutral or less toxic overall charge distribution in the bulk peptide structure, thereby reducing cytotoxicity.
3Reliability
If short peptides are used for targeting protein-protein interactions, then affinity and selectivity are improved, but structural stability in aqueous solution deteriorates
Solution Approach 1:
The patent applies parameter changes by cyclizing short peptides, which fundamentally alters the conformational entropy and structural parameters of the peptide in aqueous solution. The cyclic structure restricts the peptide to a defined conformational space, stabilizing the bioactive structure that is responsible for high affinity and selectivity toward target proteins, while preventing the peptide from adopting non-productive conformations that would reduce effectiveness.
Solution Approach 2:
The patent applies spheroidality (curvature) by introducing cyclic constraints that create a curved, pre-organized three-dimensional structure in the peptide. This curved conformation mimics the binding interface geometry of the target protein, enhancing affinity and selectivity while the cyclic constraint itself provides structural stability in aqueous solution by preventing unfolding or aggregation.
Data Source
AI summary
Disclosed herein are cyclic peptides that induce cellular autophagy and have significant cell penetration activity. Methods for inducing autophagy and thereby treating various diseases and conditions associated with impaired autophagy are provided.