. Environmental oxygen tension affects phenotype in cultured bone marrow-derived macrophages. Am J Physiol Lung Cell Mol Physiol 286: L354-L362, 2004. First published October 3, 2003 10.1152/ajplung.00380.2002This study tested the hypothesis that the unique phenotype of alveolar macrophages (AM) is maintained through adaptation to the relatively high oxygen partial pressure (PO 2) of the lung, through modification of redox-sensitive transcription factors. BALB/c mouse bone marrowderived macrophages (BMC) were differentiated under different PO 2 and compared functionally to AM and peritoneal macrophages (PM). BMC differentiated in normoxia (PO 2 140 Torr, BMChigh) were similar to AM in having low phagocytic and antigen presenting cell (APC) activities. However, BMC grown in low oxygen tension as found in other tissues (Ͻ40 Torr, BMC low) were better phagocytes and APCs, similar to PM. BMC high were more oxidative intracellularly than BMC low, based on oxidation of dichlorofluorescein and higher glutathione disulfide/glutathione (GSH) ratios, despite having more GSH. Finally, lipopolysaccharide-induced nuclear factor-B translocation, measured by laser scanning cytometry, was reduced in BMC high and AM, compared with BMClow and PM, respectively. These data suggest that regulation of the AM phenotype may occur, at least in part, via inhibition of NF-B by the unique redox environment.redox; alveolar macrophage; glutathione; nuclear factor-B

Particulates in air pollution have been strongly associated with asthma symptoms. These particulates are a conglomeration of many components, including metals, polyaromatic hydrocarbons, and lipopolysaccharide, that may cause oxidative stress upon uptake by alveolar macrophages. The objective of this study was to assess whether uptake of a model air particulate (SRM 1648) causes oxidative stress in macrophages resulting in the production of the eicosanoid mediator prostaglandin E(2) (PGE(2)) that might exacerbate asthma. SRM 1648 suspended in phosphate-buffered saline (PBS) was introduced into wells with plated RAW 264.7 monocyte/macrophages. Following incubation of SRM 1648 with RAW 264.7 macrophages, prostaglandin E(2) was measured by enzyme immunosorbent assay (EIA), and oxidative stress was assessed by the levels of intracellular reduced glutathione (GSH) as well as by the oxidation of dihydrodichlorofluorescein (H(2)DCFDA) to the fluorescent dichlorofluoresecein (DCF). The results indicated that SRM 1648 caused oxidative stress in RAW 264.7 macrophages, as shown by a compensatory increase in GSH levels in comparison to the controls of titanium dioxide and media alone. Prostaglandin E(2) levels significantly increased at the 3-, 6-, and 12-h time points. Introduction of GSH ester to buffer against oxidative stress was able to block the elevation of PGE(2). The data show that SRM 1648 causes oxidative stress in RAW 264.7 macrophages resulting in formation of the potential Th2 mediator prostaglandin E(2).