Microglia-derived HIV Nef+ exosome impairment of the blood-brain barrier is treatable by nanomedicine-based delivery of Nef peptides

J Neurovirol. 2016 Apr;22(2):129-39. doi: 10.1007/s13365-015-0397-0. Epub 2015 Dec 2.


The negative factor (Nef) of human immunodeficiency virus (HIV) is an accessory protein that is thought to be integral to HIV-associated immune- and neuroimmune pathogenesis. Here, we show that nef-transfected microglia-released Nef+ exosome (exNef) disrupts the apical blood-brain barrier (BBB) and that only nef-transfected microglia release Nef in exosomes. nef-gfp-transduced neurons and astrocytes release exosomes but did not release exNef in the extracellular space. Apical administration of exNef derived from nef-transfected 293T cells reduced transendothelial electrical resistance (TEER) and increased permeability of the BBB. Microglia-derived exNef applied to either the apical/basal BBB significantly reduced expression of the tight junction protein, ZO-1, suggesting a mechanism of exNef-mediated neuropathogenesis. Microglia exposed to exNef release elevated levels of Toll-like receptor-induced cytokines and chemokines IL-12, IL-8, IL-6, RANTES, and IL-17A. Magnetic nanoparticle delivery of Nef peptides containing the Nef myrisolation site across an in vitro BBB ultimately reduced nef-transfected microglia release of Nef exosomes and prevented the loss of BBB integrity and permeability as measured by TEER and dextran-FITC transport studies, respectively. Overall, we show that exNef is released from nef-gfp-transfected microglia; exNef disrupts integrity and permeability, and tight junctions of the BBB, and induces microglial cytokine/chemokine secretion. These exNef-mediated effects were significantly restricted by Nef peptides. Taken together, this study provides preliminary evidence of the role of exNef in HIV neuroimmune pathogenesis and the feasibility of a nanomedicine-based therapeutics targeting exNef to treat HIV-associated neuropathogenesis.

Keywords: BBB impairment; Nanoparticle therapeutics; Nef + exosomes.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Blood-Brain Barrier / drug effects
  • Blood-Brain Barrier / metabolism
  • Cell Line
  • Chemokine CCL5 / genetics
  • Chemokine CCL5 / immunology
  • Drug Carriers / pharmacology*
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Exosomes / metabolism*
  • Gene Expression Regulation
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • HEK293 Cells
  • HIV-1 / chemistry
  • Humans
  • Interleukins / genetics
  • Interleukins / immunology
  • Magnetite Nanoparticles / chemistry
  • Microglia / cytology
  • Microglia / drug effects*
  • Microglia / metabolism
  • Models, Biological
  • Peptides / chemical synthesis
  • Peptides / pharmacology*
  • Signal Transduction
  • Transfection
  • Transgenes
  • nef Gene Products, Human Immunodeficiency Virus / antagonists & inhibitors
  • nef Gene Products, Human Immunodeficiency Virus / genetics*
  • nef Gene Products, Human Immunodeficiency Virus / metabolism
  • nef Gene Products, Human Immunodeficiency Virus / pharmacology


  • CCL5 protein, human
  • Chemokine CCL5
  • Drug Carriers
  • Interleukins
  • Magnetite Nanoparticles
  • Peptides
  • nef Gene Products, Human Immunodeficiency Virus
  • nef protein, Human immunodeficiency virus 1
  • Green Fluorescent Proteins