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Synchronized activation of alveolar macrophages determined by live alveolar imaging
Author(s) -
Westphalen Kristin,
Islam Mohammad Naimul,
Bhattacharya Jahar
Publication year - 2013
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.27.1_supplement.914.5
Subject(s) - yellow fluorescent protein , lung , microbiology and biotechnology , chemistry , cytosol , immunology , biology , medicine , biochemistry , gene , enzyme
Alveolar macrophages (AMs) play a major role in lung defense against pathogens. However, it is not known whether AMs intercommunicate signals in response to pathogen challenge. To determine AM signals in situ , we crossed CD11cCre mice with R26‐LSL‐EYFP floxed mice to obtain mice containing EYFP‐expressing AMs (AM YFP ). We gave i.n. endotoxin (1 mg/kg) or buffer (control) to AM YFP expressing mice, then after 24 h, we excised and blood‐perfused their lungs at constant pulmonary artery, left atrial and alveolar pressures. We viewed the lungs by live confocal microscopy, to image 30–40 alveoli containing a total of 10–15 AM YFP . To detect cytosolic Ca 2+ signals as a marker of activation, we microinfused alveoli with the Ca 2+ ‐sensitive dye, fluo‐4 (10μM). In control lungs, AM YFP cytosolic Ca 2+ levels were stable. By contrast in endotoxin‐treated lungs, AM activation was indicated in that 45±5% of the AM YFP evoked slow‐frequency Ca 2+ spikes (2±1 spikes/20 min) of which 67±3% occurred synchronously amongst the activated AM YFP . We show here for the first time, that AMs can be viewed in situ in real time, and that following endotoxin treatment, subsets of AMs evoke synchronized Ca 2+ signaling, suggesting that endotoxin‐challenged AMs develop network responses. AM networks may orchestrate lung defense against endotoxin challenge (HL78645, HL64896).