New GHK hydrophobic derivatives: interaction with phospholipid bilayers

Area of Science:

• Biochemistry
• Materials Science
• Biophysics

Background:

• GHK peptide is a naturally occurring peptide with various biological activities.
• Hydrophobic modifications of peptides can alter their interaction with biological membranes.
• Liposomes are widely used as drug delivery systems.

Purpose of the Study:

• To synthesize and characterize novel hydrophobic GHK peptide derivatives.
• To investigate the binding of these peptidolipids to phospholipid bilayers and liposomes.
• To evaluate their hemolytic activity and influence on liposome physicochemical properties.

Main Methods:

• Synthesis of N-terminal acylated GHK peptide derivatives (hexanoyl, decanoyl, myristoyl).
• Lipid-binding assays using liposomes.
• Carboxyfluorescein leakage assay to assess membrane integrity.
• Asymmetric membrane method (NBD-PE/dithionite) and fluorescence quenching studies (PC-pyrene/KI) to study membrane interaction.
• Microviscosity measurements of DPPC bilayers using TMA-DPH.
• Hemolysis assays.

Main Results:

• Synthesized peptidolipids exhibit high affinity for ordered lipids in liposomes.
• No significant release of entrapped carboxyfluorescein was observed, indicating preserved liposome integrity.
• Peptidolipid association protected liposomes from reactants, with hydrophobic moieties inserting into the bilayer.
• Microviscosity of DPPC bilayers remained unaffected.
• Myristoyl-GHK induced total hemolysis at 2.5x10(-4)M, while decanoyl and hexanoyl derivatives showed minimal hemolysis (10%) at 5x10(-4)M.

Conclusions:

• Hydrophobic GHK peptide derivatives bind strongly to liposomes without compromising their structure.
• The insertion of the hydrophobic tail into the lipid bilayer offers a protective effect.
• Myristoyl-GHK demonstrates significant hemolytic activity, suggesting potential for specific membrane interactions or applications.
• These findings highlight the potential of tailored peptidolipids for modulating membrane properties and drug delivery.