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Connexin 43 gap junctions contribute to brain endothelial barrier hyperpermeability in familial cerebral cavernous malformations type III by modulating tight junction structure
Author(s) -
Johnson Allison M.,
Roach James P.,
Hu Anna,
Stamatovic Svetlana M.,
Zochowski Michal R.,
Keep Richard F.,
Andjelkovic Anuska V.
Publication year - 2018
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/fj.201700699r
Subject(s) - connexin , gap junction , tight junction , gene knockdown , blood–brain barrier , small interfering rna , microbiology and biotechnology , claudin , cell junction , chemistry , biology , intracellular , transfection , cell culture , neuroscience , central nervous system , cell , biochemistry , genetics
Familial cerebral cavernous malformations type III (fCCM3) is a disease of the cerebrovascular system caused by loss‐of‐function mutations in ccm3 that result in dilated capillary beds that are susceptible to hemorrhage. Before hemorrhage, fCCM3 lesions are characterized by a hyperpermeable blood‐brain barrier (BBB), the key pathologic feature of fCCM3. We demonstrate that connexin 43 (Cx43), a gap junction (GJ) protein that is incorporated into the BBB junction complex, is up‐regulated in lesions of a murine model of f CCM3. Small interfering RNA‐mediated ccm3 knockdown (CCM3KD) in brain endothelial cells in vitro increased Cx43 protein expression, GJ plaque size, GJ intracellular communication (GJIC), and barrier permeability. CCM3KD hyperpermeability was rescued by GAP27, a peptide gap junction and hemichannel inhibitor of Cx43 GJIC. Tight junction (TJ) protein, zonula occludens 1 (ZO‐1), accumulated at Cx43 GJs in CCM3KD cells and displayed fragmented staining at TJs. The GAP27‐mediated inhibition of Cx43 GJs in CCM3KD cells restored ZO‐1 to TJ structures and reduced plaque accumulation at Cx43 GJs. The TJ protein, Claudin‐5, was also fragmented at TJs in CCM3KD cells, and GAP27 treatment lengthened TJ‐associated fragments and increased Claudin 5‐Claudin 5 transinteraction. Overall, we demonstrate that Cx43 GJs are aberrantly increased in fCCM3 and regulate barrier permeability by a TJ‐dependent mechanism.—Johnson, A. M., Roach, J. P., Hu, A., Stamatovic, S. M., Zochowski, M. R., Keep, R. F., Andjelkovic, A. V. Connexin 43 gap junctions contribute to brain endothelial barrier hyperpermeability in familial cerebral cavernous malformations type III by modulating tight junction structure. FASEB J. 32, 2615–2629 (2018). www.fasebj.org