title: Connexin43 is dispensable for phagocytosis.
abstract: Macrophages that lack connexin43 (Cx43), a gap junction protein, have been reported to exhibit dramatic deficiencies in phagocytosis. In this study, we revisit these findings using well-characterized macrophage populations. Cx43 knockout (Cx43(-/-)) mice die soon after birth, making the harvest of macrophages from adult Cx43(-/-) mice problematic. To overcome this obstacle, we used several strategies: mice heterozygous for the deletion of Cx43 were crossed to produce Cx43(+/+) (wild type [WT]) and Cx43(-/-) fetuses. Cells isolated from 12- to 14-d fetal livers were used to reconstitute irradiated recipient animals. After reconstitution, thioglycollate-elicited macrophages were collected by peritoneal lavage and bone marrow was harvested. Bone marrow cells and, alternatively, fetal liver cells were cultured in media containing M-CSF for 7-10 d, resulting in populations of cells that were >95% macrophages based on flow cytometry. Phagocytic uptake was detected using flow cytometric and microscopic techniques. Quantification of phagocytic uptake of IgG-opsonized sheep erythrocytes, zymosan particles, and Listeria monocytogenes failed to show any significant difference between WT and Cx43(-/-) macrophages. Furthermore, the use of particles labeled with pH-sensitive dyes showed equivalent acidification of phagosomes in both WT and Cx43(-/-) macrophages. Our findings suggest that modulation of Cx43 levels in cultured macrophages does not have a significant impact on phagocytosis.
authors.affiliation: Department of Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Glass
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Wolf
authors.forename: Karin M
authors.initials: KM
authors.lastname: Schneider
authors.forename: Michael F
authors.initials: MF
authors.lastname: Princiotta
authors.forename: Steven M
authors.initials: SM
authors.lastname: Taffet
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism; D002478:Cells, Cultured; D018031:Connexin 43 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004912:Erythrocytes / Q000276:immunology / Q000378:metabolism; D005260:Female; D005805:Genes, MHC Class I; D007074:Immunoglobulin G / Q000235:genetics / Q000378:metabolism; D008089:Listeria monocytogenes / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010587:Phagocytosis / Q000235:genetics / Q000276:immunology*; D010588:Phagosomes / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012756:Sheep; D015054:Zymosan / Q000235:genetics / Q000378:metabolism
chemical_list: D018031:Connexin 43; D007074:Immunoglobulin G; D016173:Macrophage Colony-Stimulating Factor; D015054:Zymosan
references.citation: J Biol Chem. 1998 Dec 11;273(50):33619-23
references.pmid: 9837946
references.citation: J Cell Biol. 1988 Mar;106(3):649-56
references.pmid: 2831233
references.citation: Front Biosci. 2007 Jan 01;12:2683-92
references.pmid: 17127272
references.citation: Immunity. 1997 Jun;6(6):715-26
references.pmid: 9208844
references.citation: Mol Immunol. 2009 Sep;46(15):2938-46
references.pmid: 19608277
references.citation: J Immunol. 2013 Mar 15;190(6):2501-9
references.pmid: 23396941
references.citation: J Immunol. 2011 Sep 15;187(6):3121-32
references.pmid: 21844382
references.citation: J Exp Med. 1997 Oct 6;186(7):1027-39
references.pmid: 9314552
references.citation: Prog Biophys Mol Biol. 2007 May-Jun;94(1-2):207-18
references.pmid: 17467043
references.citation: J Immunol. 2008 Dec 15;181(12):8534-8543
references.pmid: 19050272
references.citation: J Exp Med. 1979 Sep 19;150(3):580-96
references.pmid: 90108
references.citation: J Leukoc Biol. 1985 Nov;38(5):655-8
references.pmid: 3862731
references.citation: Science. 1995 Mar 24;267(5205):1831-4
references.pmid: 7892609
references.citation: J Immunol. 2009 Jul 15;183(2):1083-90
references.pmid: 19553546
references.citation: J Endotoxin Res. 2003;9(3):176-80
references.pmid: 12831459
references.citation: EMBO J. 1999 Jul 15;18(14):3956-63
references.pmid: 10406800
references.citation: Mol Immunol. 2011 Jan;48(4):463-71
references.pmid: 21067810
references.citation: J Exp Med. 1976 Mar 1;143(3):631-47
references.pmid: 1082493
references.citation: Eur J Immunol. 1981 Oct;11(10):805-15
references.pmid: 7308288