Related Experiment Video
Updated: Dec 28, 2025
Setting-up an In Vitro Model of Rat Blood-brain Barrier BBB: A Focus on BBB Impermeability and Receptor-mediated Transport
Published on: June 28, 2014
DPepH3, an Improved Peptide Shuttle for Receptor-independent Transport Across the Blood-Brain Barrier
Marco Cavaco1,2, Javier Valle2, Ruben da Silva3
1Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028 Lisboa, Portugal.
Background:
The use of peptides as drug carriers across the blood-brain barrier (BBB) has increased significantly during the last decades. PepH3, a seven residue sequence (AGILKRW) derived from the α-helical domain of the dengue virus type-2 capsid protein, translocates across the BBB with very low toxicity. Somehow predictably from its size and sequence, PepH3 is degraded in serum relatively fast. Among strategies to increase peptide half-life (t1/2), the use of the enantiomer (wholly made of D-amino acid residues) can be quite successful if the peptide interacts with a target in non-stereospecific fashion.
Methods:
The goal of this work was the development of a more proteolytic-resistant peptide, while keeping the translocation properties. The serum stability, cytotoxicity, in vitro BBB translocation, and internalization mechanism of DPepH3 was assessed and compared to the native peptide.
Results:
DPepH3 demonstrates a much longer t1/2 compared to PepH3. We also confirm that BBB translocation is receptor-independent, which fully validates the enantiomer strategy chosen. In fact, we demonstrate that internalization occurs trough macropinocytosis. In addition, the enantiomer demonstrates to be non-cytotoxic towards endothelial cells as PepH3.
Conclusion:
DPepH3 shows excellent translocation and internalization properties, safety, and improved stability. Taken together, our results place DPepH3 at the forefront of the second generation of BBB shuttles.
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