A cell-penetrating peptide derived from human lactoferrin with conformation-dependent uptake efficiency

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• Cell-penetrating peptides (CPPs) facilitate cellular uptake of molecules.
• Mechanisms of CPP internalization are not fully understood.
• Heparan sulfate and peptide conformation influence cellular entry.

Purpose of the Study:

• To identify and characterize a novel CPP from lactoferrin.
• To investigate the role of peptide conformation and heparan sulfate in cellular uptake.
• To elucidate the molecular events governing CPP internalization.

Main Methods:

• Peptide identification and synthesis.
• Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD) spectroscopy.
• Surface Plasmon Resonance (SPR) and cell-based uptake assays.

Main Results:

• A 22-amino acid CPP derived from lactoferrin was identified.
• Peptide uptake efficiency is conformation-dependent, linked to heparan sulfate binding.
• A disulfide bridge is crucial for rapid cytoplasmic entry, influenced by lipid interactions.
• Oxidized peptide shows higher affinity for heparan sulfate and enhanced cellular uptake.

Conclusions:

• Lactoferrin-derived peptide exhibits conformation-dependent cellular uptake.
• Disulfide bridge and heparan sulfate interactions are critical for CPP internalization.
• Findings provide insights into CPP mechanisms and potential therapeutic applications.