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Control of the Ca 2+ ‐Mediated Endothelial Cell Migration by Connexin 43‐Formed Hemichannels
Author(s) -
AMADOR HILDA ESPINOZA,
CORDOVA ALEXANDRA,
FIGUEROA XAVIER
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.517.2
Subject(s) - microbiology and biotechnology , connexin , paracrine signalling , autocrine signalling , endothelial stem cell , caveolae , cell migration , intracellular , angiogenesis , gap junction , endothelium , chemistry , cell signaling , connexon , caveolin 1 , cell junction , cell , biology , signal transduction , biochemistry , cancer research , receptor , endocrinology , in vitro
Endothelial cell migration is a key process in endothelium repair, tube formation and angiogenesis. The initiation and progress of endothelial cell migration is orchestrated by the generation of coordinated Ca 2+ signals through Ca 2+ release from the intracellular stores and Ca 2+ entry. However, the molecular pathways involved in the Ca 2+ influx have not been determined. Connexins (Cx) play a central role in the coordination of endothelial cell function, directly by cell‐to‐cell communication via gap junction and, indirectly, by the release of autocrine/paracrine signals through Cx‐formed hemmichannels. In addition to the release of signaling molecules, connexin hemichannels are permeable to Ca 2+ and, thus, the opening of these channels may contribute to the Ca 2+ influx observed during endothelial cell migration. Endothelial cells mainly express Cxs 37, 40 and 43 and, of these three connexin proteins, Cx43 has been reported to form hemichannels in endothelial cells. Interestingly, caveolae seems to be involved in the coordination of the Ca 2+ ‐mediated endothelial cell migration and Cx43 has been found to be associated with caveolin‐1, a structural protein of the caveolae. However, the participation of Cx43 in endothelial cell migration has not been determined. Primary cultures of mesenteric endothelial cells were used to evaluate cell migration by the wound healing assay. Cx43 and caveolin‐1 distribution was assessed by immunofluorescence, activation of Cx hemichannels by measuring ethidium uptake and changes in intracellular Ca 2+ concentration [Ca 2+ ] i by loading the cells with Fluo‐4. The scratch of the endothelial cell monolayer with a micropipette tip induced a strong increase in [Ca 2+ ] i and ethidium uptake by cells of the migration front, but not those of the monolayer. Treatment with 18‐b‐Glycyrrhetenic acid (bGA, 50 μM), a general connexin‐formed channel blocker, 37,43 GAP27 (200 μM), a Cx37 and Cx43 blocking peptide, and TAT‐Gap19 (300 μM), a Cx43 hemichannels specific blocking peptide, blunted the increase in [Ca 2+ ] i and, consistent with the participation of Cx43 in this process, 37,43 GAP27 also reduced the increment in ethidium uptake. In addition, endothelial cell migration was associated with the re‐localization of Cx43 and caveolin‐1 to the rear part of the cells in the migration front, which was prevented by the treatment with TAT‐Gap19. As expected, bGA and TAT‐Gap19 also inhibited the endothelial cell migration rate. These results indicate that Cx43 hemichannels play a central role in the coordination of the Ca 2+ signaling that mediates the endothelial cell migration. Support or Funding Information Grants: FONDECYT 1150530 and CONICYT 21170977 This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .