title: TAT is not capable of transcellular delivery across an intact endothelial monolayer in vitro.
abstract: Developing delivery vehicles capable of penetrating cell barriers is critical for drug delivery to the brain due to the presence of the blood-brain barrier (BBB). Cell-penetrating peptides (CPPs) are one potential solution since they can enter cells; however, it is unclear whether CPPs can pass through cell barriers. In this study, the ability of the TAT CPP to cross an endothelial barrier without disrupting the integrity of its tight junctions was investigated. Endothelial cell monolayers (bEnd.3) were exposed to the TAT peptide, and cell integrity was quantified by zona occludens-1 immunofluorescence, trans-endothelial electrical resistance, and hydraulic conductivity. None of these parameters were significantly altered following exposure to TAT. To evaluate the passage of TAT through the monolayer, the permeability of a green fluorescent protein (GFP)-TAT fusion protein was not significantly different from the permeability of GFP or fluorescent dextrans of similar sizes. Furthermore, GFP-TAT was unable to significantly transduce astrocytes on the opposite side of the bEnd.3 monolayer. We conclude, therefore, that although TAT may not be an efficient delivery vehicle for trans-BBB delivery, our TAT construct may have utility in delivering therapeutic cargos to endothelial cells or to the brain parenchyma after BBB disruption.
authors.affiliation: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace MC 8904, 1210 Amsterdam Avenue, New York, NY 10027, USA.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Simon
authors.forename: Woo Hyeun
authors.initials: WH
authors.lastname: Kang
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.forename: Scott
authors.initials: S
authors.lastname: Banta
authors.forename: Barclay
authors.initials: B
authors.lastname: Morrison
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism*; D002460:Cell Line; D004337:Drug Carriers / Q000493:pharmacokinetics*; D042783:Endothelial Cells / Q000378:metabolism*; D015696:Gene Products, tat / Q000493:pharmacokinetics*; D051379:Mice; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004337:Drug Carriers; D015696:Gene Products, tat