Involvement of the low-density lipoprotein receptor-related protein in the transcytosis of the brain delivery vector angiopep-2

J Neurochem. 2008 Aug;106(4):1534-44. doi: 10.1111/j.1471-4159.2008.05492.x. Epub 2008 May 19.


The blood-brain barrier (BBB) restricts the entry of proteins as well as potential drugs to cerebral tissues. We previously reported that a family of Kunitz domain-derived peptides called Angiopeps can be used as a drug delivery system for the brain. Here, we further characterize the transcytosis ability of these peptides using an in vitro model of the BBB and in situ brain perfusion. These peptides, and in particular Angiopep-2, exhibited higher transcytosis capacity and parenchymal accumulation than do transferrin, lactoferrin, and avidin. Angiopep-2 transport and accumulation in brain endothelial cells were unaffected by the P-glycoprotein inhibitor, cyclosporin A, indicating that this peptide is not a substrate for the efflux pump P-glycoprotein. However, competition studies show that activated alpha(2)-macroglobulin, a specific ligand for the low-density lipoprotein receptor-related protein-1 (LRP1) and Angiopep-2 can share the same receptor. In addition, LRP1 was detected in glioblastomas and brain metastases from lung and skin cancers. Fluorescent microscopy also revealed that Alexa488-Angiopep-2 co-localized with LRP1 in brain endothelial cell monolayers. Overall, these results suggest that Angiopep-2 transport across the BBB is, in part, mediated by LRP1.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood-Brain Barrier / metabolism
  • Blood-Brain Barrier / physiology*
  • Brain / physiology*
  • Cattle
  • Cell Line, Tumor
  • Cells, Cultured
  • Drug Delivery Systems / methods*
  • Genetic Vectors / administration & dosage
  • Genetic Vectors / metabolism
  • Humans
  • Low Density Lipoprotein Receptor-Related Protein-1 / physiology*
  • Oligopeptides / physiology*
  • Peptide Fragments / administration & dosage
  • Peptide Fragments / metabolism*
  • Protein Transport / physiology
  • Rats
  • Somatostatin / analogs & derivatives*
  • Somatostatin / physiology


  • Low Density Lipoprotein Receptor-Related Protein-1
  • Oligopeptides
  • Peptide Fragments
  • lanreotide
  • Somatostatin