Abstract
The aim of this study was to identify cell adhesion molecules that could serve as targets of the human follicle-associated epithelium (FAE) overlying Peyer's patches and to assess nanoparticle uptake levels across this epithelium. We first studied the expression of the mouse M-cell marker β1-integrin and used a model of human FAE derived from intestinal epithelial Caco-2 cells and Raji B-cells to identify additional potential targets by cDNA array. The protein expression of potential targets in the model FAE and in human ileal FAE tissues was quantified by immunofluorescence. Integrin targeting was studied by investigating the transport of Arg-Gly-Asp (RGD)-coated (integrin-binding), Arg-Gly-Glu (RGE)-coated (nonintegrin-binding), and uncoated nanoparticles across ileal specimens mounted in Ussing chambers. Both β1-integrin and the cell adhesion molecule CD9 were more abundantly expressed in the model and human FAE compared with the Caco-2 control cells or villus epithelium (VE). Uncoated nanoparticles were not taken up across either FAE or VE. General integrin targeting with RGD improved the nanoparticle transport dramatically across the FAE and to a lower extent across the VE. Compared with RGE, RGD improved transport 4-fold across the FAE. There was no difference in the transport of RGD- and RGE-coated nanoparticles across the VE. In conclusion, β1-integrin and CD9 were identified as targets in human FAE. The difference in RGD- and RGE-mediated transport across the FAE, but not the VE, suggests that a specific integrin interaction was the dominating mechanism for improved nanoparticle uptake across the FAE., whereas charge interaction contributed substantially to the improved VE uptake.
Footnotes
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This work was supported by the Swedish National Association of Pharmaceutical Scientists, by the Swedish Research Council (Vetenskapsradet-medicin), by the Broad Medical Research Program of the Eli and Edythe L. Broad Foundation, and by AstraZeneca R&D Mölndal, Sweden
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.106.107847.
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ABBREVIATIONS: VE, villus epithelium; FAE, follicle-associated epithelium; PP, Peyer's patches; TEER, transepithelial electrical resistance; HBSS, Hanks' balanced salt solution; RGD, Arg-Gly-Asp tripeptide; RGE, Arg-Glu-Glu tripeptide; PBS, phosphate-buffered saline; PCR, polymerase chain reaction; VED, villus epithelium adjacent to dome; ANOVA, analysis of variance; sRGD, soluble RGD.
- Received May 27, 2006.
- Accepted August 15, 2006.
- The American Society for Pharmacology and Experimental Therapeutics