Design of cyclized selective melanotropins

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Biotechnology

Background:

• G-protein coupled receptors (GPCRs) are crucial drug targets.
• Peptides often face degradation in the digestive tract, limiting oral bioavailability.
• Cyclic peptides offer enhanced stability and potential for therapeutic applications.

Purpose of the Study:

• To develop cyclic peptides targeting G-protein coupled receptors for novel therapeutics.
• To explore structure-function relationships of cyclic peptides in the melanocortin system.
• To engineer orally available peptide-based drugs.

Main Methods:

• Design and synthesis of cyclic peptides using solid-phase methodology.
• Two cyclization strategies: global constraint via linkers and using natural cyclotide scaffolds.
• Grafting the melanotropin pharmacophore (-His-Phe-Arg-Trp-) onto cyclotides.
• Biological evaluation of synthesized peptides for potency and selectivity.

Main Results:

• Successful synthesis of modified cyclic peptides.
• Demonstrated resistance to digestion, enabling oral delivery potential.
• Identification of selective and potent ligands for melanocortin receptors.
• Some analogs showed oral bioavailability.

Conclusions:

• Cyclic peptides are promising scaffolds for GPCR-targeted therapeutics.
• Cyclization strategies enhance peptide stability and drug-like properties.
• Engineered cyclic peptides can lead to potent, selective, and orally available drugs.