自引率: 1.7%
被引量: 10491
通过率: 暂无数据
审稿周期: 1.9
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国人发稿量: 106
期刊描述简介:
Laboratory Investigation is an international journal owned by the United States and Canadian Academy of Pathology. Laboratory Investigation offers prompt publication of high-quality original research in all biomedical disciplines relating to the understanding of human disease and the application of new methods to the diagnosis of disease. Both human and experimental studies are welcome.
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Selectin-mediated interactions regulate cytokine networks and macrophage heme oxygenase-1 induction in cardiac allograft recipients.
Host sensitization to major histocompatibility complex (MHC) antigens is among the most critical of problems facing heart transplantation. Selectins are postulated to mediate the early adhesive events in the recruitment of leukocytes at the allograft site. We investigated the significance of selectin-P-selectin glycoprotein ligand-1 (PSGL-1)-mediated in vivo interactions in the immune cascade leading to rejection of cardiac allografts in skin presensitized rats. Infusion of a soluble recombinant form of PSGL-1 (rPSGL-Ig) during skin graft-mediated sensitization prevented Day 1.0 +/- 0.1 "accelerated" rejection in sensitized rat recipients, and prolonged cardiac allograft survival to Day 3.8 +/- 1.0 (p < 0.001). This therapy significantly depressed serum IgM levels and decreased intragraft expression of Th1 type cytokines (IL-2 and IFN-gamma) as well as of IL-1beta and MCP-1, as compared with controls, without affecting the initial number of infiltrating mononuclear cells (MNC). A profound decrease in graft-infiltrating MNC was recorded at 24 hours in rPSGL-Ig-treated rats. The expression of heme oxygenase-1 (HO-1), an inducible heat shock protein 32 that protects against oxidative cell/tissue injury, was found in approximately 14-fold higher levels in the rPSGL-Ig-treated recipients as compared with controls. The HO-1 overexpression in rPSGL-Ig-treated hosts, primarily by infiltrating macrophages, was accompanied by virtual absence of myocardial infarcts and decreased frequency of TUNEL + cells at the graft site. Moreover, down-regulation of HO-1 expression by zinc protoporphyrin, an HO-1 antagonist, decreased expression of antiapoptotic Bag-1 molecule in recipients conditioned with rPSGL-Ig. Thus, the blockade of selectin-PSGL-1 interactions depresses intracardiac allograft expression of Th1 type cytokines, and might inhibit the differentiation of Th1 type cells. In addition, it up-regulates HO-1 expression and protects against myocardial infarction and apoptosis. Hence, this study reports on a previously unrecognized role of selectin-PSGL-1-mediated interactions after in vivo alloantigenic challenge.
被引量：- 发表：2002
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Induction of inducible nitric oxide synthase is an essential part of tumor necrosis factor-alpha-induced apoptosis in MCF-7 and other epithelial tumor cells.
TNF-alpha-induced cytotoxicity is mediated by the intracellular "death domain" of the 55-kDa TNF-alpha receptor and has been demonstrated to be coupled with induction of inducible nitric oxide synthase (iNOS), leading to generation of nitric oxide radicals (NO*). Because it is still widely unknown, to what extent NO* participates in the execution of TNF-alpha-induced apoptosis, NO* production, iNOS expression, and enzyme activity in relation to TNF-alpha-induced apoptotic cell death were investigated in the human breast cancer cell line MCF-7 and various other malignant cell lines. Incubation with TNF-alpha led to induction of iNOS mRNA and protein as well as enhancement of NOS activity. Augmented synthesis of NO2, the stable end product of NO* generation, was significantly correlated with augmented rates of cell death. Measurement of TNF-alpha-triggered production of reactive oxygen species (ROS) suggested a major role for NO* within the generated oxygen radicals. Dying cells showed characteristic features of apoptosis. Addition of cycloheximide (CX) enhanced apoptotic cell death by increasing iNOS activity. L-Nitro-arginine-methylester (L-NAME), a competitive NOS-inhibitor, and iNOS antisense oligonucleotides effectively prevented NO2 generation and apoptosis. Evaluation of iNOS expression during TNF-alpha-induced cell death in various malignant cell lines demonstrated iNOS positivity for all TNF-alpha-sensitive cells. The only primarily resistant line was iNOS negative. In a resistant variant of MCF-7, iNOS mRNA was still detectable; however, treatment with TNF-alpha did not enhance NOS activity. TNF-alpha sensitivity and NO2 production were completely restored by the addition of CX. Taken together, iNOS induction plays an essential role in TNF-alpha-induced apoptosis of the investigated cell lines. Further studies are necessary to define the impact of NO* in relation to other specific effectors of apoptosis such as the caspases.
被引量：- 发表：1999
