The brain microvasculature is comprised of a specialized class of endothelium that forms a cellular barrier between the bloodstream and the interstices of the brain. This so-called blood-brain barrier (BBB) distinguishes the brain microvasculature from peripheral vascular beds because it constitutes a physical and metabolic barrier that tightly regulates brain uptake of ions, small molecules, proteins, and circulating cells. Since brain endothelial cell plasma membranes contact both the bloodstream and brain interstitial fluid, they are ideally positioned to act as the controlling interfaces for signaling, immune regulation, and transport between the blood and brain. Therefore, many of the unique characteristics of the BBB endothelium can likely be attributed to the protein composition of its plasma membranes. In particular, the receptor-mediated transport (RMT) systems at the BBB play major functional roles in healthy brain function by controlling the transport of large molecules into and out of the brain. Moreover, RMT systems can also affect disease processes by either their dysfunction or by their direct participation in transporting substances involved in disease progression (e.g. beta-amyloid, HIV virus, measles virus). Finally, given the capability for RMT systems to transport large molecules, they have been increasingly used as a means for shuttling drug cargo into the brain noninvasively. Although RMT systems are a highly significant class of proteins, they have been understudied as a consequence of technological shortcomings. RMT receptors are membrane proteins that because of their low abundance and hydrophobicity are not well profiled using traditional two dimensional gel or tandem mass spectrometry methods. In addition, since the BBB comprises only 1/1000 of the brain total volume, proteomics studies using total brain tissue likely miss many of the important RMT systems in play at the BBB. Therefore, in this EUREKA proposal we will use a new, state-of-the-art technological platform developed in our laboratory that combines the power of antibody libraries with detergent-solubilized BBB plasma membrane lysates to simultaneously identify antibodies and cognate BBB RMT proteins. Because detergents can be employed, the hydrophobic nature of membrane proteins that often hampers other proteomics technologies can be overcome, thereby promising a broader coverage of the BBB RMT proteome (RMT-ome). Moreover, the approach enables such subcellular BBB membrane proteomics with high in vivo relevance because freshly isolated and subfractionated BBB is used as source tissue. Finally, our new approaches allow functional membrane proteomics in that identified membrane proteins can be readily categorized by their functional association with a generalized component of RMT systems. Taking advantage of these new tools, receptors and machinery that are involved in receptor-mediated transport (RMT) function at the BBB will be identified. Identified antibodies targeting RMT machinery will then used to assess RMT expression levels and tissue localization as well as to validate the transport function of the RMT machinery. Successful completion of the proposed research is predicted to have substantial impact not only for neuroscientists and cell biologists alike, but ultimately for the treatment of millions suffering from neurological disease.

Public Health Relevance

HEALTH RELEVANCE Novel functional membrane proteomics techniques capable of focusing on the receptor mediated transport machinery of the BBB will shed light on how nutrients, cytokines, pathogens, and cells distribute across the comparatively impermeable BBB. In addition, identification of antibodies capable of targeting receptor-mediated transport systems could yield new noninvasive portals for brain drug delivery and have a significant impact on our ability to translate new therapeutics into clinically viable drugs for the treatment of millions of patients who suffer from debilitating neurological diseases.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZNS1-SRB-B (21))
Program Officer
Bosetti, Francesca
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Wisconsin Madison
Engineering (All Types)
Schools of Engineering
United States
Zip Code
Silva, E; Frost, D; Li, L et al. (2017) Lactadherin is a candidate oviduct Lewis X trisaccharide receptor on porcine spermatozoa. Andrology 5:589-597
Cohen, Hannah Caitlin; Frost, Dustin C; Lieberthal, Tyler Jacob et al. (2015) Biomaterials differentially regulate Src kinases and phosphoinositide 3-kinase-? in polymorphonuclear leukocyte primary and tertiary granule release. Biomaterials 50:47-55
Lajoie, Jason M; Shusta, Eric V (2015) Introducing glycophage arrays: facile production, purification and patterning of glycophages. Biotechnol J 10:20-1
Lajoie, Jason M; Shusta, Eric V (2015) Targeting receptor-mediated transport for delivery of biologics across the blood-brain barrier. Annu Rev Pharmacol Toxicol 55:613-31
Tillotson, Benjamin J; Goulatis, Loukas I; Parenti, Isabelle et al. (2015) Engineering an Anti-Transferrin Receptor ScFv for pH-Sensitive Binding Leads to Increased Intracellular Accumulation. PLoS One 10:e0145820
Tillotson, Benjamin J; Lajoie, Jason M; Shusta, Eric V (2015) Yeast Display-Based Antibody Affinity Maturation Using Detergent-Solubilized Cell Lysates. Methods Mol Biol 1319:65-78
Frost, Dustin C; Greer, Tyler; Li, Lingjun (2015) High-resolution enabled 12-plex DiLeu isobaric tags for quantitative proteomics. Anal Chem 87:1646-54
Frost, Dustin C; Greer, Tyler; Xiang, Feng et al. (2015) Development and characterization of novel 8-plex DiLeu isobaric labels for quantitative proteomics and peptidomics. Rapid Commun Mass Spectrom 29:1115-24
Frost, Dustin C; Li, Lingjun (2014) Recent advances in mass spectrometry-based glycoproteomics. Adv Protein Chem Struct Biol 95:71-123
Yang, Chenxi; Zhong, Xuefei; Li, Lingjun (2014) Recent advances in enrichment and separation strategies for mass spectrometry-based phosphoproteomics. Electrophoresis 35:3418-29

Showing the most recent 10 out of 15 publications