Aromatic-Cationic Peptides for Mitochondrial Targeting
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Solution Overview
Problem
Current treatments for mitochondrial permeability transition (MPT) are inadequate, as existing drugs like cyclosporin A do not specifically target mitochondria, are poorly delivered to the brain, and have immunosuppressant side effects, failing to effectively inhibit MPT in conditions such as ischemia-reperfusion and neurodegenerative diseases.
Innovation Solution
Administration of aromatic-cationic peptides with specific charge and aromatic group ratios that penetrate cell membranes and mitochondria, reducing or preventing MPT by maintaining mitochondrial membrane integrity and function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclosporin A is used to inhibit MPT, then MPT inhibition is achieved, but the drug does not specifically target mitochondria and has immunosuppressant side effects
Solution Approach 1:
The patent applies local quality by designing peptides with specific aromatic and cationic characteristics that enable selective accumulation in mitochondria. The aromatic-cationic peptides (e.g., SS-02, SS-31) contain aromatic amino acids (phenylalanine, tyrosine, tryptophan) and basic amino acids (arginine, lysine, histidine) that confer mitochondrial targeting capability, allowing the drug to concentrate specifically at the mitochondrial site of action rather than distributing systemically, thereby reducing side effects while maintaining MPT inhibition effectiveness.
Solution Approach 2:
The patent employs parameter changes by optimizing the molecular structure of the peptides through specific ratios of aromatic groups to net positive charges. The aromatic-cationic peptides are designed with 2-4 aromatic groups and 3-6 net positive charges at physiological pH, with specific molecular weights (600-1000 Da). These parameter optimizations enable the peptides to penetrate cell membranes and accumulate in mitochondria via electrochemical gradients, achieving selective mitochondrial targeting and MPT inhibition without the immunosuppressant side effects of cyclosporin A.
2Reliability
If existing drugs are used to treat MPT, then some MPT inhibition is achieved, but delivery to the brain is poor
Solution Approach 1:
The patent applies parameter changes by optimizing the molecular weight of the peptides to 600-1000 Da and designing specific aromatic-cationic structures that facilitate blood-brain barrier penetration. The aromatic-cationic peptides with molecular weights in this range and specific charge-to-size ratios can cross the blood-brain barrier more efficiently than larger molecules or those with different chemical characteristics, enabling effective brain delivery for treating neurodegenerative diseases while maintaining MPT inhibition capability.
3Reliability
If aromatic-cationic peptides are designed with specific charge and aromatic group ratios, then mitochondrial targeting and MPT inhibition are improved, but peptide structure complexity increases
Solution Approach 1:
The patent resolves the complexity issue by establishing clear quantitative parameters: 2-4 aromatic groups, 3-6 net positive charges at physiological pH, molecular weights of 600-1000 Da, and specific amino acid compositions. These defined parameters provide a systematic framework for peptide design, making the complex task of mitochondrial targeting achievable through rational design rather than random screening. The specific ratios and counts of aromatic and cationic groups create a standardized approach that simplifies the design process while ensuring effective mitochondrial accumulation and MPT inhibition.
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 aromatic-cationic peptides effectively inhibit MPT, delaying mitochondrial depolarization and cytochrome c release, and enhance cardiac contractile force during ischemia-reperfusion, offering a targeted and specific therapeutic approach for conditions associated with MPT.
Implementation Method 1
The peptides of the present invention can penetrate cell membranes and mitochondrial membranes
Implementation Method 2
aromatic-cationic peptides with specific charge and aromatic group ratios
Implementation Method 3
reducing or preventing MPT by maintaining mitochondrial membrane integrity and function
Implementation Method 4
delaying mitochondrial depolarization
Data Source
AI summary
The invention provides a method of reducing or preventing mitochondrial permeability transitioning. The method comprises administering an effective amount of an aromatic-cationic peptide having at least one net positive charge; a minimum of four amino acids; a maximum of about twenty amino acids; a relationship between the minimum number of net positive charges (pm) and the total number of amino acid residues (r) wherein 3pm is the largest number that is less than or equal to r+1; and a relationship between the minimum number of aromatic groups (a) and the total number of net positive charges (pt) wherein 2a is the largest number that is less than or equal to pt+1, except that when a is 1, pt may also be 1.