title: Gap junction-mediated intercellular communication between dendritic cells (DCs) is required for effective activation of DCs.
abstract: Gap junctions, formed by members of the connexin (Cx) family, are intercellular channels allowing direct exchange of signaling molecules. Gap junction-mediated intercellular communication (GJIC) is a widespread mechanism for homeostasis in organs. GJIC in the immune system is not yet fully understood. Although dendritic cells (DC) reportedly form cell-to-cell contact between DCs in nonlymphoid and lymphoid organs, GJIC between DCs remains unknown. In this study we examined whether DCs form GJIC. XS52 and bone marrow-derived DCs (BMDCs) were tested for GJIC by counting intercellular transfer of Lucifer Yellow microinjected into a cell. Either DC became effectively dye-coupled when activated with LPS plus IFN-gamma or TNF-alpha plus IFN-gamma. LPS- plus IFN-gamma-induced dye-coupling was mediated by DC-derived TNF-alpha. In addition, CpG plus IFN-gamma induced dye-coupling in BMDCs, which was also mediated by DC-derived TNF-alpha. LPS- plus IFN-gamma-induced activation of DCs (assessed by CD40 expression) was observed when there was cell-to-cell contact and was significantly blocked by heptanol, a gap junction blocker. These results indicate that cell-to-cell contact and GJIC are required for effective DC activation. In addition, heptanol significantly inhibited the LPS- plus IFN-gamma-induced up-regulation of the other costimulatory (i.e., CD80 and CD86) and MHC class II molecules expressed by BMDCs, and it significantly reduced their allostimulatory capacity. Among Cx members, Cx43 was up-regulated in dye-coupled BMDCs, and Cx mimetic peptide, a blocker of Cx-mediated GJIC, significantly inhibited the dye-coupling and activation, suggesting the involvement of Cx43. Thus, our study provides the first evidence for GJIC between DCs, which is required for effective DC activation.
authors.affiliation: Department of Dermatology, University of Yamanashi, Interdisciplinary Graduate School of Medicine and Engineering Tamaho, Yamanashi, Japan. hmatsue@yamanashi.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsue
authors.forename: Jian
authors.initials: J
authors.lastname: Yao
authors.forename: Keiko
authors.initials: K
authors.lastname: Matsue
authors.forename: Akiko
authors.initials: A
authors.lastname: Nagasaka
authors.forename: Hideaki
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Rui
authors.initials: R
authors.lastname: Aoki
authors.forename: Masanori
authors.initials: M
authors.lastname: Kitamura
authors.forename: Shinji
authors.initials: S
authors.lastname: Shimada
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019013:CD40 Antigens / Q000276:immunology; D002450:Cell Communication / Q000187:drug effects / Q000276:immunology*; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology*; D019850:Heptanol / Q000494:pharmacology; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D019013:CD40 Antigens; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D019850:Heptanol