Murine endometrial and decidual NK1.1+ natural killer cells display a B220+CD11c+ cell surface phenotype.

Uterine natural killer (uNK) cells accumulate at the maternal-fetal interface during gestation and are thought to have an important role during pregnancy in both mice and humans. While the cell surface phenotype of human uNK cells is increasingly well defined, less is known regarding the cell surface expression profile of murine uNK cells both before and during gestation. Herein, we demonstrate that murine NK1.1(+) (KLRB1C) endometrial NK (eNK) cells, derived from virgin mice, and NK1.1(+) decidual NK (dNK) cells, obtained from pregnant mice, belong to the B220(+) (PTPRC) CD11c(+) (ITGAX) subset of NK cells. While B220 expression was low on NK1.1(+) eNK cells, it was increased on a subset of NK1.1(+) dNK cells at Embryonic Day 10.5. Endometrial NK and dNK cells also differed somewhat in their expression patterns of two activation markers, namely, CD69 and inducible costimulator (ICOS). The eNK cells acquired a B220(hi)ICOS(+) dNK cell surface phenotype when cultured in vitro in the presence of uterine cells and murine interleukin 15. Thus, the cell surface profiles generated for both NK1.1(+) eNK cells and dNK cells demonstrate that they belong to the recently described B220(+)CD11c(+) subset of NK cells, which are potent cytokine producers.

Ionizing radiation up-regulates cyclooxygenase-2 in I407 cells through p38 mitogen-activated protein kinase.

The epithelial cell line I407 up-regulates cyclooxygenase-2 (COX-2) mRNA and protein expression following ionizing radiation exposure. Prostaglandin E2 (PGE2) production is concomitantly up-regulated. Irradiation of I407 cells also results in phosphorylation of the p38 mitogen-activated protein kinase and the p38 inhibitor SB203580 abrogates radiation-induced PGE2 synthesis. Wild-type p38alpha (p38alphaWT) and dominant-negative p38alpha (p38alphaDN) stable-transfectant clones of I407 cells were used to examine the role of the p38 mitogen-activated protein kinase pathway in the events controlling PGE2 synthesis after ionizing radiation. Treatment of p38alphaWT clones with gamma-radiation resulted in increased COX-2 protein levels and PGE2 synthesis similar to treated control-transfected cells. In contrast, the p38alphaDN clones failed to up-regulate COX-2 protein or increase PGE2 synthesis when irradiated. Exogenous arachidonate did not restore PGE2 synthesis by p38alphaDN cells. Radiation increased COX-2 mRNA stability and the p38 inhibitor SB203580 attenuated COX-2 mRNA stability in irradiated I407 cells. In contrast, irradiation had no effect on transcription from a COX-2 promoter/luciferase reporter plasmid in the presence or absence of SB203580. The data demonstrate a crucial role for p38alpha in COX-2 expression and PGE2 synthesis in an irradiated transformed epithelial cell line. Furthermore, they indicate that p38 activity is required at a step distal to arachidonate release, most probably COX-2 up-regulation, since exogenous arachidonate did not restore PGE2 synthesis.

Basic fibroblast growth factor upregulates cyclooxygenase-2 in I407 cells through p38 MAP kinase.

The intestinal cell line I407 responds to basic fibroblast growth factor (bFGF) by upregulating cyclooxygenase-2 (COX-2) mRNA and protein expression and increasing PGE(2) production. bFGF treatment of I407 cells results in phosphorylation of p38, and the p38 inhibitor SB-203580 abrogates bFGF-induced PGE(2) synthesis. Wild-type p38alpha (p38alphaWT) and dominant-negative p38alpha (p38alphaDN) stable transfectant clones of I407 cells were used to examine the role of the p38 MAP kinase pathway in the events controlling PGE(2) synthesis after treatment with bFGF. Treatment of p38alphaWT clones with bFGF resulted in increased COX-2 protein levels and PGE(2) synthesis similar to those seen in bFGF-treated control-transfected cells. In contrast, the p38alphaDN clones failed to upregulate COX-2 protein or increase PGE(2) synthesis when treated with bFGF. Exogenous arachidonate did not restore PGE(2) synthesis by p38alphaDN cells. bFGF treatment increased COX-2 mRNA stability, and the p38 inhibitor SB-203580 attenuated COX-2 mRNA stability in bFGF-treated I407 cells. These data demonstrate a crucial role for p38alpha in growth factor-induced PGE(2) synthesis by intestinal cells. Furthermore, they indicate that p38 activity is required at a step distal to arachidonate release, most likely COX-2 upregulation, because exogenous arachidonate did not restore PGE(2) synthesis.

Inhibition of indoleamine 2,3-dioxygenase augments trinitrobenzene sulfonic acid colitis in mice.

BACKGROUND & AIMS: Indoleamine 2,3-dioxygenase (IDO), an interferon gamma-induced intracellular enzyme, inhibits lymphocyte proliferation through tryptophan degradation. IDO is highly expressed in the mammalian intestine. We sought to determine whether IDO played a regulatory role in the T-cell helper 1 (Th1)-mediated trinitrobenzene sulfonic acid (TNBS) model of colitis. METHODS: Intrarectal TNBS was given to SJL/J mice along with either placebo or a specific IDO inhibitor. IDO protein and mRNA expression were assessed by Western blotting and real-time PCR. Colonic lamina propria mononuclear cells (LPMNCs) were isolated, fractionated, and cultured, in the presence and absence of IFN-gamma, to determine the cell type(s) expressing IDO. RESULTS: IDO is expressed by professional antigen-presenting cells in the lamina propria. Induction of TNBS colitis resulted in a significant increase in IDO mRNA (P = 0.005) and protein expression. IDO inhibition during TNBS colitis resulted in an 80% mortality compared with 10% for placebo-treated animals (P = 0.0089). IDO inhibition resulted in a more severe colitis both histologically and morphologically (P < 0.05) and significantly increased colonic proinflammatory cytokine expression compared with placebo-treated animals. CONCLUSIONS: IDO is expressed in the normal colon and is up-regulated in the setting of TNBS colitis. Inhibition of IDO during TNBS colitis resulted in increased mortality and an augmentation of the normal inflammatory response. These findings suggest that IDO plays an important role in the down-regulation of Th1 responses within the gastrointestinal tract.