title: Trafficking of adeno-associated virus vectors across a model of the blood-brain barrier; a comparative study of transcytosis and transduction using primary human brain endothelial cells.
abstract: Developing therapies for central nervous system (CNS) diseases is exceedingly difficult because of the blood-brain barrier (BBB). Notably, emerging technologies may provide promising new options for the treatment of CNS disorders. Adeno-associated virus serotype 9 (AAV9) has been shown to transduce cells in the CNS following intravascular administration in rodents, cats, pigs, and non-human primates. These results suggest that AAV9 is capable of crossing the BBB. However, mechanisms that govern AAV9 transendothelial trafficking at the BBB remain unknown. Furthermore, possibilities that AAV9 may transduce brain endothelial cells or affect BBB integrity still require investigation. Using primary human brain microvascular endothelial cells as a model of the human BBB, we performed transduction and transendothelial trafficking assays comparing AAV9 to AAV2, a serotype that does not cross the BBB or transduce endothelial cells effectively in vivo. Results of our in vitro studies indicate that AAV9 penetrates brain microvascular endothelial cells barriers more effectively than AAV2, but has reduced transduction efficiency. In addition, our data suggest that (i) AAV9 penetrates endothelial barriers through an active, cell-mediated process, and (ii) AAV9 fails to disrupt indicators of BBB integrity such as transendothelial electrical resistance, tight junction protein expression/localization, and inflammatory activation status. Overall, this report shows how human brain endothelial cells configured in BBB models can be utilized for evaluating transendothelial movement and transduction kinetics of various AAV capsids. Importantly, the use of a human in vitro BBB model can provide import insight into the possible effects that candidate AVV gene therapy vectors may have on the status of BBB integrity. Read the Editorial Highlight for this article on page 192.
authors.affiliation: Department of Pathology and Laboratory Medicine, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.|Center for Substance Abuse Research, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.
authors.forename: Steven F
authors.identifier: 0000-0003-2889-5187
authors.initials: SF
authors.lastname: Merkel
authors.affiliation: Department of Pathology and Laboratory Medicine, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.|Center for Substance Abuse Research, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.
authors.forename: Allison M
authors.identifier: 0000-0003-1752-7450
authors.initials: AM
authors.lastname: Andrews
authors.affiliation: Department of Pathology and Laboratory Medicine, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.
authors.forename: Evan M
authors.initials: EM
authors.lastname: Lutton
authors.affiliation: Department of Neurology, The Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: Dakai
authors.initials: D
authors.lastname: Mu
authors.affiliation: Department of Neurology, The Massachusetts General Hospital, Charlestown, Massachusetts, USA.|NeuroDiscovery Center, Harvard Medical School, Boston, Massachusetts, USA.|Alzheimer Research Unit, The Massachusetts General Hospital Institute for Neurodegenerative Disease, Charlestown, Massachusetts, USA.
authors.forename: Eloise
authors.initials: E
authors.lastname: Hudry
authors.affiliation: Department of Neurology, The Massachusetts General Hospital, Charlestown, Massachusetts, USA.|NeuroDiscovery Center, Harvard Medical School, Boston, Massachusetts, USA.|Alzheimer Research Unit, The Massachusetts General Hospital Institute for Neurodegenerative Disease, Charlestown, Massachusetts, USA.
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Hyman
authors.affiliation: Department of Neurology, The Massachusetts General Hospital, Charlestown, Massachusetts, USA.|NeuroDiscovery Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Casey A
authors.initials: CA
authors.lastname: Maguire
authors.affiliation: Department of Pathology and Laboratory Medicine, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.|Center for Substance Abuse Research, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.|Shriners Hospitals Pediatric Research Center, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.
authors.forename: Servio H
authors.initials: SH
authors.lastname: Ramirez
mesh_terms: D001812:Blood-Brain Barrier / Q000166:cytology / Q000821:virology*; D001921:Brain / Q000378:metabolism / Q000821:virology*; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D000229:Dependovirus; D042783:Endothelial Cells / Q000821:virology*; D006801:Humans; D019108:Tight Junctions / Q000821:virology*; D057900:Transcytosis / Q000502:physiology
keywords: adeno-associated virus; blood-brain barrier; gene therapy; neurological disorders