Calibrated flux measurements reveal a nanostructure-stimulated transcytotic pathway

• Type of Material: Article
• Authors: Tarianna Stewart, Morehouse School of Medicine; William T. Koval, Emory University; Samuel Molina, Emory University; Suzanne M. Bock, Kimberly Clark Inc; James W. Lillard, Morehouse School of Medicine; Russell F. Ross, Kimberly Clark Corporation; Tejal A. Desai, University of California San Francisco; Michael H Koval, Emory University
• Language: English
• Date: 2017-06-15
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Elsevier Inc.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.yexcr.2017.03.065
• Title of Journal or Parent Work: Experimental Cell Research
• ISSN: 0014-4827
• Volume: 355
• Issue: 2
• Start Page: 153
• End Page: 161
• Grant/Funding Information: Funding for this work was provided by National Institutes of Health R01-EB018842, U54-CA118638, R25-GM058268, G12-MD007602 and Kimberly-Clark Corporation.; This research project was supported in part by the Emory University Integrated Cellular Imaging Microscopy Core.
• Keywords: Transcytosis; Drug delivery; Oncology; FUSION PROTEINS; APICAL JUNCTIONAL COMPLEX; TIGHT JUNCTION; EPITHELIAL BARRIER FUNCTION; Tight junctions; Science & Technology; FcRn; PARACELLULAR DRUG ABSORPTION; Calcium switch; Cell Biology; Life Sciences & Biomedicine; Nanotopography; THERAPEUTICS; DELIVERY; Epithelial permeability; NEONATAL FC-RECEPTOR; MYOSIN-II MOTOR; MONOCLONAL-ANTIBODIES
• Research Categories: Health Sciences, Medicine and Surgery; Engineering, Biomedical

Abstract

Transport of therapeutic agents across epithelial barriers is an important element in drug delivery. Transepithelial flux is widely used as a measure of transit across an epithelium, however it is most typically employed as a relative as opposed to absolute measure of molecular movement. Here, we have used the calcium switch approach to measure the maximum rate of paracellular flux through unencumbered intercellular junctions as a method to calibrate the flux rates for a series of tracers ranging in 0.6–900 kDa in size across barriers composed of human colon epithelial (Caco-2) cells. We then examined the effects of nanostructured films (NSFs) on transepithelial transport. Two different NSF patterns were used, Defined Nanostructure (DN) 2 imprinted on polypropylene (PP) and DN3 imprinted on polyether ether ketone (PEEK). NSFs made direct contact with cells and decreased their barrier function, as measured by transepithelial resistance (TER), however cell viability was not affected. When NSF-induced transepithelial transport of Fab fragment (55 kDa) and IgG (160 kDa) was measured, it was unexpectedly found to be significantly greater than the maximum paracellular rate as predicted using cells cultured in low calcium. These data suggested that NSFs stimulate an active transport pathway, most likely transcytosis, in addition to increasing paracellular flux. Transport of IgG via transcytosis was confirmed by immunofluorescence confocal microscopy, since NSFs induced a significant level of IgG endocytosis by Caco-2 cells. Thus, NSF-induced IgG flux was attributable to both transcytosis and the paracellular route. These data provide the first demonstration that transcytosis can be stimulated by NSFs and that this was concurrent with increased paracellular permeability. Moreover, NSFs with distinct architecture paired with specific substrates have the potential to provide an effective means to regulate transepithelial transport in order to optimize drug delivery.