Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Resident macrophages have been suggested to participate in the initiation of beta cell damage during the development of autoimmune diabetes. The purpose of this study was to determine if the endogenous production and release of interleukin 1 (IL-1) in human islets of Langerhans by resident macrophages results in the inhibition of beta cell function. Treatment of human islets with a combination of tumor necrosis factor (TNF) + lipopolysaccharide (LPS) + interferon-gamma (IFN-gamma) stimulates inducible nitric oxide synthase (iNOS) expression, nitric oxide production, and inhibits glucose-stimulated insulin secretion. The IL-1 receptor antagonist protein (IRAP) prevents TNF + LPS + IFN-gamma-induced iNOS expression and nitrite production, and attenuates the inhibitory effects on glucose-stimulated insulin secretion by human islets. Inhibition of iNOS activity by aminoguanidine also attenuates TNF + LPS + IFN-gamma-induced inhibition of insulin secretion by human islets. These results indicate that the inhibitory effects of TNF + LPS + IFN-gamma are mediated by nitric oxide, produced by the actions of IL-1 released endogenously within human islets. Reverse transcriptase polymerase chain reaction was used to confirm that TNF + LPS + IFN-gamma stimulates the expression of both IL-1alpha and IL-1beta in human islets. Two forms of evidence indicate that resident macrophages are the human islet cellular source of IL-1: culture conditions that deplete islet lymphoid cells prevent TNF + LPS + IFN-gamma-induced iNOS expression, nitric oxide production, and IL-1 mRNA expression by human islets; and IL-1 and the macrophage surface marker CD69 colocalize in human islets treated with TNF + LPS + IFN-gamma as determined by immunohistochemical analysis. Lastly, nitric oxide production is not required for TNF + LPS + IFN-gamma-induced IL-1 release in human islets. However, cellular damage stimulates IL-1 release by islet macrophages. These findings support the hypothesis that activated islet macrophages may mediate beta cell damage during the development of insulin-dependent diabetes by releasing IL-1 in human islets followed by cytokine-induced iNOS expression by beta cells.
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PMID:IL-1 produced and released endogenously within human islets inhibits beta cell function. 969 Oct 88

Clinical features of the CREST (calcinosis cutis, Raynaud's syndrome, esophageal dysmotility, sclerodactyly, and telangiectasias) syndrome are sometimes exhibited in patients with primary biliary cirrhosis (PBC), but the postulated autoimmune mechanisms behind these conditions are poorly understood. Clonally expanded T cells may play an important role in disease pathogenesis. In this study, overrepresentation of one T-cell receptor beta chain variable region, TCRBV3, was documented in patients with PBC and/or CREST. Overrepresentation of the TCRBV3 gene mRNA was demonstrated by semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR). T cells expressing TCRBV3 were analyzed by flow cytometry, were primarily CD8(+), and contained activated cells as assessed by expression of CD69. Clonally expanded T cells within this population were documented by both complementarity determining region 3 (CDR3) length polymorphism analysis and sequencing of T-cell receptor CDR3 cDNA. TCRBV3(+) clonal expansions were stable when followed for up to 5 years. The results of this study demonstrate that the T-cell repertoire of patients with PBC and CREST is characterized by expanded clonal populations of CD8(+) TCRBV3(+) T cells. These clonal expansions provide evidence that stimulation of clonal populations of CD8(+) T cells is associated with the clinical syndrome of PBC with CREST.
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PMID:Association of clonally expanded T cells with the syndrome of primary biliary cirrhosis and limited scleroderma. 1034 1

Survivin is a member of the inhibitor-of-apoptosis (IAP) family. It has been reported to be expressed during development, but not in differentiated normal tissue. However, its expression has been reported to be high in the thymus. To assess the role of survivin in human thymocyte development, we investigated the expression of survivin using reverse-transcriptase-polymerase chain reaction, flow cytometry, and immunohistochemistry in freshly isolated human thymocytes. Survivin was expressed in all thymocyte subsets but its expression level was developmentally regulated. Its expression was low in the double negative (DN) thymocytes, upregulated in double positive (DP) thymocytes, and was highest in the T-cell receptor(high), late DP thymocytes; it was then downregulated in the single positive thymocytes and negative in the peripheral blood T cells. Moreover, there was a positive correlation between the expression of survivin and that of CD69 and Bcl-2 in DP thymocytes. These results suggest that survivin may play an important role in the T-cell development in the human thymus.
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PMID:Developmentally regulated expression of survivin in the human thymus. 1182 Nov 57

Artemisinin derivatives are potent antimalarial compounds that may have immunomodulatory properties. Artesunate (range 0.01-2 mirog/ml) or dihydroartemisinin (range 0.01-8 microg/ml; DHART) were added to peripheral blood mononuclear cells (PBMC) or whole blood (WB) cultures before or simultaneously upon stimulation with phytohemagglutinin (PHA), a T cell mitogen. Lymphoproliferation was then measured by 3[H]-thymidine incorporation, and CD4+ and CD8+ T cell activation was assessed by expression of CD69 or CD25 using flow cytometry. Reverse transcriptase polymerase chain reaction depicted PBMC mRNA production for interleukins 2, 4, 12, and 15, interferon-gamma, and tumor necrosis factor-alpha. Artesunate concentrations between 0.1-1.5 microg/ml reduced lymphoproliferation in PHA-stimulated PBMC and WB cultures in a generally dose-dependent manner; inhibition by DHART was similar. Removing artesunate from PBMC before PHA was added abolished the reduction. PBMCs cultured with artesunate or DHART simultaneously with PHA showed modestly reduced proportions of CD4+ and CD8+ T cells expressing CD69 and CD25. Artesunate had little effect on qualitative cytokine mRNA levels in PHA-stimulated PBMC cultures. Artesunate and DHART may diminish some PBMC responses to immunologic stimuli. Further work is warranted to define the mechanisms involved, and whether this affects malaria treatment.
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PMID:Artesunate and a major metabolite, dihydroartemisinin, diminish mitogen-induced lymphocyte proliferation and activation. 1733 24