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Mitochondrial ROS regulate surfactant secretion in pulmonary alveoli
Author(s) -
Monma Eiji,
Parthasarathi Kaushik,
Lindert Jens,
Ichimura Hideo,
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.20.5.a1442-a
Subject(s) - exocytosis , lamellar granule , reactive oxygen species , mitochondrial ros , secretion , chemistry , mitochondrion , lung , microbiology and biotechnology , pulmonary surfactant , medicine , biology , biochemistry
In alveolar type 2 cells, lamellar body (LB) exocytosis causes surfactant secretion. To determine underlying mechanisms we imaged single alveolar cells in the isolated blood‐perfused rat lung held at baseline pulmonary artery, left atrial, and airway (P alv ) pressures of 10, 3 and 5 cmH 2 O, respectively. By alveolar micropuncture, we co‐loaded alveolar epithelial cells with the fluorescent dyes, LysoTracker Green (LTG) and 2′,7′‐dichlorodihydrofluorescein diacetate (DCFH‐DA) to detect LB and reactive oxygen species (ROS), respectively. At baseline, fluorescence for both dyes remained steady for 30 min. However, a transient 15‐s increase of P alv to 15 cmH 2 O decreased LTG fluorescence by 90±2% of baseline (mean±SE, P<0.05, n=3), indicating onset of LB exocytosis. Concomitantly, DCF fluorescence increased 40±4 gray levels from baseline (mean±SE, P<0.05, n=3), indicating increased ROS production. Pretreating the alveoli with the mitochondrial complex 1 inhibitor, rotenone (1 μM, 15 min) blocked both the inflation‐induced LB exocytosis and ROS production. We conclude that lung inflation induced mitochondrial ROS production, which in turn, activated LB exocytosis (Support: HL 64896).