Isolation of peptide transport system-6 from brain endothelial cells: therapeutic effects with antisense inhibition in Alzheimer and stroke models

J Cereb Blood Flow Metab. 2009 Feb;29(2):411-22. doi: 10.1038/jcbfm.2008.131. Epub 2008 Nov 12.


By isolating for the first time ever a peptide transporter from the blood-brain barrier (BBB) and developing an antisense that selectively targets the brain-to-blood efflux component, we were able to deliver a therapeutic concentration of the neurotrophic peptide pituitary adenylate cyclase-activating polypeptide (PACAP) 27 to brain in animal models of Alzheimer's and stroke. Efflux pumps at the BBB are major causes of BBB impermeability to peptides. PACAP is neuroprotective in vitro in femtomole amounts, but brain uptake of PACAP27 is limited by an efflux component of peptide transport system-6 (PTS-6). Here, we characterized, isolated, and sequenced this component of PTS-6, identifying it as beta-F1 ATPase, and colocalized it with PACAP27 on BBB endothelial cells. Antisenses targeting the BBB inhibited PACAP27 efflux, thus increasing brain uptake of PACAP27. Treatment with antisense+PACAP27 improved cognition in a mouse model of Alzheimer's disease and reduced infarct size after cerebral ischemia. This represents the first isolation from BBB tissue of a peptide transporter and shows that inhibition of peptide efflux pumps is a potential strategy for drug delivery to brain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Alzheimer Disease / enzymology*
  • Alzheimer Disease / genetics
  • Alzheimer Disease / pathology
  • Alzheimer Disease / therapy
  • Animals
  • Brain / enzymology*
  • Disease Models, Animal
  • Endothelial Cells / enzymology*
  • Genetic Therapy
  • Male
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / isolation & purification*
  • Membrane Transport Proteins / metabolism*
  • Mice
  • Oligonucleotides, Antisense / genetics*
  • Pituitary Adenylate Cyclase-Activating Polypeptide / metabolism
  • Protein Binding
  • Stroke / enzymology*
  • Stroke / genetics
  • Stroke / pathology
  • Stroke / therapy


  • Membrane Transport Proteins
  • Oligonucleotides, Antisense
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • peptide permease
  • Adenosine Triphosphatases