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Ca 2+ communication through connexin 43 in lung capillaries
Author(s) -
Parthasarathi Kaushik,
Bhattacharya Jahar
Publication year - 2006
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.20.4.a275-c
Subject(s) - connexin , egta , gap junction , chemistry , lung , biophysics , intracellular , microbiology and biotechnology , calcium , biochemistry , biology , medicine , organic chemistry
The extent to which endothelial (EC) cells support gap junctional intercellular communication (GJIC) remains unknown. To determine GJIC, by fluorescence microscopy we viewed septal capillaries of isolated, blood‐perfused lungs from wild type (WT) mice, and from mice with targeted deletion of the gap junctional protein, connexin 43 (Cx43) in EC (Cx43 ‐/‐ ) (Liao, et al., PNAS, 2001). Lung artery, left atrial and airway pressures were held at 10, 3 and 5 cm H 2 O, respectively. We co‐loaded vessels with the Ca 2+ cage, NP‐EGTA and the cytosolic Ca 2+ (Ca 2+ cyt ) indicator, fluo 4. At baseline, EC Ca 2+ cyt was 88±17 gray levels. To increase Ca 2+ cyt focally, we targeted high‐intensity UV light to a single EC of a septal capillary, thereby uncaging Ca 2+ from NP‐EGTA. In WT mice, uncaging increased EC Ca 2+ cyt locally as well as at a site 100 μm distant by 33±2 and 29±2 gray levels, respectively (mean±SE, n=3, P<0.05). By contrast, in Cx43 ‐/‐ mice uncaging increased Ca 2+ cyt locally (n=3, P<0.05), but not at a distant site. Thus, the uncaging‐induced Ca 2+ signal was conducted 100 μm from the uncaging site in WT, but not in Cx43 ‐/‐ mice. We conclude, EC of lung capillaries rapidly communicate Ca 2+ signals through Cx43‐containing gap junctions. Such spatial communication may amplify Ca 2+ ‐dependent proinflammatory responses in the lung capillary bed (supported by HL75503, HL57556).