rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1995-11-9
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pubmed:abstractText |
We previously reported that difluoromethylornithine (DFMO), an inhibitor of polyamine biosynthesis, exerted significant beneficial effects on the lifespan and disease expression of MRL-lpr/lpr mice, which spontaneously develop a lupus-like syndrome. Polyamine levels in splenic T-cells of MRL-lpr/lpr mice were significantly higher than those of Balb/c mice. In the present investigation, we examined the role of endogenous polyamines in transmembrane Ca2+ influx, generation of InsP3 and tyrosine phosphorylation of the p56lck protein in concanavalin A-stimulated splenic T-cells. Cytosolic free calcium concentrations ([Ca2+]i) in concanavalin A-stimulated T-cells of MRL-lpr/lpr and Balb/c mice were 250 +/- 25 and 450 +/- 42 nM respectively. Treatment of MRL-lpr/lpr mice with DFMO increased [Ca2+]i to 360 +/- 30 nM (P < 0.05). InsP3 levels of concanavalin A-stimulated MRL-lpr/lpr splenic T-cells were only 20% higher than those of unstimulated controls, whereas those of Balb/c T-cells were 90% higher. DFMO treatment increased InsP3 levels in concanavalin A-treated MRL-lpr/lpr T-cells to 67%. Western-blot analysis showed a 7-fold higher level of p56lck phosphorylation of MRL-lpr/lpr splenic T-cells than that of Balb/c mice. DFMO treatment reduced tyrosine phosphorylation of p56lck of MRL-lpr/lpr mice significantly (P < 0.001). Two-colour flow-cytometric analysis revealed no significant difference in the CD4+/CD8+ ratio in splenic T-cells of MRL-lpr/lpr mice after DFMO treatment. Polyamine levels in splenocytes were significantly reduced by DFMO treatment. These data show that DFMO treatment could alter signal-transduction pathways of splenic T-cells of MRL-lpr/lpr mice. Increased levels of polyamines in T-cells of untreated lpr mice contribute to defective signal-transduction pathways and the pathogenesis of lupus-like symptoms.
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pubmed:grant |
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pubmed:commentsCorrections |
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0264-6021
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
311 ( Pt 1)
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
175-82
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:7575451-Animals,
pubmed-meshheading:7575451-Mice,
pubmed-meshheading:7575451-Spleen,
pubmed-meshheading:7575451-Lupus Erythematosus, Systemic,
pubmed-meshheading:7575451-Calcium,
pubmed-meshheading:7575451-Phosphorylation,
pubmed-meshheading:7575451-Female,
pubmed-meshheading:7575451-Autoimmune Diseases,
pubmed-meshheading:7575451-Mice, Inbred BALB C,
pubmed-meshheading:7575451-Polyamines,
pubmed-meshheading:7575451-T-Lymphocytes,
pubmed-meshheading:7575451-Concanavalin A,
pubmed-meshheading:7575451-Signal Transduction,
pubmed-meshheading:7575451-Ornithine Decarboxylase,
pubmed-meshheading:7575451-Inositol Phosphates,
pubmed-meshheading:7575451-Eflornithine,
pubmed-meshheading:7575451-Phosphotyrosine
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