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The lipoxins are the first proresolution mediators to be recognized and described as the endogenous "braking signals" for inflammation. We evaluated the anti-inflammatory and proresolution bioactions of lipoxin A4 in our lipopolysaccharide (LPS-)induced lung injury model. We demonstrated that lipoxin A4 significantly improved histology of rat lungs and inhibited IL-6 and TNF-α in LPS-induced lung injury. In addition, lipoxin A4 increased alveolar fluid clearance (AFC) and the effect of lipoxin A4 on AFC was abolished by CFTRinh-172 (a specific inhibitor of CFTR).Moreover, lipoxin A4 could increase cystic fibrosis transmembrane conductance regulator (CFTR) protein expression in vitro and in vivo. In rat primary alveolar type II (ATII) cells, LPS decreased CFTR protein expression via activation of PI3K/Akt, and lipoxin A4 suppressed LPS-stimulated phosphorylation of Akt. These results showed that lipoxin A4 enhanced CFTR protein expression and increased AFC via PI3K/Akt pathway. Thus, lipoxin A4 may provide a potential therapeutic approach for acute lung injury. [ABSTRACT FROM AUTHOR]

Aim. To investigate the role of Ca2+ release-activated Ca2+ (CRAC) channels in the ROS production in macrophages. Methods. The intracellular [Ca2+]i was analyzed by confocal laser microscopy. The production of ROS was assayed by flow cytometry. Results. Both LPS and thapsigargin induced an increase in intracellular [Ca2+]i, either in the presence or absence of extracellular Ca2+ in murine macrophages. The Ca2+ signal was sustained in the presence of external Ca2+ and only initiated a mild and transient rise in the absence of external Ca2+. CRAC channel inhibitor 2-APB completely suppressed the Ca2+ entry signal evoked by thapsigargin, and suppressed approximately 93% of the Ca2+ entry signal evoked by LPS. The increase in intracellular [Ca2+]i was associated with increased ROS production, which was completely abolished in the absence of extracellular Ca2+ or in the presence of CRAC channel inhibitors 2-APB and Gd3+. The mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxy-phenylhydrazone and the inhibitor of the electron transport chain, antimycin, evoked a marked increase in ROS production and completely inhibited thapsigargin and LPS-evoked responses. Conclusions. These findings indicate that the LPS-induced intracellular [Ca2+]i increase depends on the Ca2+ entry through CRAC channels, and close functional coupling between CRAC and ROS production in murine macrophages. [ABSTRACT FROM AUTHOR]