Interaction of enkephalin peptides with anionic model membranes

Area of Science:

• Biophysics
• Pharmacology
• Membrane Biology

Background:

• Passive transport across biological membranes is crucial for drug delivery.
• Membrane surface charge is a key factor influencing molecular interactions and transport.
• Understanding peptide-membrane interactions is vital for developing effective peptide-based therapeutics.

Purpose of the Study:

• To investigate the effect of membrane surface charge on the permeability and interaction of analgesic peptide ligands.
• To elucidate the role of electrostatic interactions in peptide-membrane transport.
• To assess the potential impact of natural cell membrane charge on peptide drug delivery.

Main Methods:

• Utilized model membranes composed of zwitterionic phospholipids and cholesterol.
• Controlled membrane surface charge density by incorporating anionic lipids.
• Studied the permeability and binding of two potent analgesic peptides: c[D-Pen(2),D-Pen(5)]enkephalin (DPDPE) and biphalin.

Main Results:

• Increased negative surface charge moderately decreased the permeability of zwitterionic DPDPE, attributed to a reduced partition coefficient.
• The binding of dicationic biphalin ligands to membranes increased with higher negative surface charge.
• This enhanced binding significantly reduced biphalin permeability by impeding its diffusion across the lipid bilayer.

Conclusions:

• Electrostatic effects play a critical role in peptide-membrane interactions.
• The negative charge of cell membranes may impede the transport of cationic peptide drugs.
• Targeted strategies or transporters may be necessary to overcome charge-related transport barriers for certain peptide therapeutics.