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BioMed Research International
Volume 2014, Article ID 803257, 8 pages
http://dx.doi.org/10.1155/2014/803257
Research Article

Connexin 43 Expression on Peripheral Blood Eosinophils: Role of Gap Junctions in Transendothelial Migration

Pulmonary Research Group, Department of Medicine, University of Alberta, 550 HMRC, Edmonton, AB, Canada T6G 2S2

Received 26 February 2014; Revised 11 June 2014; Accepted 12 June 2014; Published 6 July 2014

Academic Editor: Robert Movérare

Copyright © 2014 Harissios Vliagoftis et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Eosinophils circulate in the blood and are recruited in tissues during allergic inflammation. Gap junctions mediate direct communication between adjacent cells and may represent a new way of communication between immune cells distinct from communication through cytokines and chemokines. We characterized the expression of connexin (Cx)43 by eosinophils isolated from atopic individuals using RT-PCR, Western blotting, and confocal microscopy and studied the biological functions of gap junctions on eosinophils. The formation of functional gap junctions was evaluated measuring dye transfer using flow cytometry. The role of gap junctions on eosinophil transendothelial migration was studied using the inhibitor 18-a-glycyrrhetinic acid. Peripheral blood eosinophils express Cx43 mRNA and protein. Cx43 is localized not only in the cytoplasm but also on the plasma membrane. The membrane impermeable dye BCECF transferred from eosinophils to epithelial or endothelial cells following coculture in a dose and time dependent fashion. The gap junction inhibitors 18-a-glycyrrhetinic acid and octanol did not have a significant effect on dye transfer but reduced dye exit from eosinophils. The gap junction inhibitor 18-a-glycyrrhetinic acid inhibited eosinophil transendothelial migration in a dose dependent manner. Thus, eosinophils from atopic individuals express Cx43 constitutively and Cx43 may play an important role in eosinophil transendothelial migration and function in sites of inflammation.