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AIM:To explore whether histamine can regulate the expression of early growth response factor-1 (Egr-1) in the cerebral cortex astrocytes.METHODS:Normal wild-type (WT) mice, histidine decarboxylase knockout ( HDC-KO) mice and histamine treated HDC-KO mice were sacrificed for extracting the total RNA of the cerebral cortex. Primary cultured rat cortical astrocytes were treated with histamine at concentrations of 10 -8 , 10 -7 , 10 -6 , 10 -5 or 10 -4 mol/L for 15, 30, 60, 120 or 240 min.H1 or H2 receptor antagonists were pretreated for 15 min before histamine treat-ment.After histamine treatment, the cell total RNA or protein was extracted.The expression of Egr-1 at mRNA and protein levels was determined by real-time PCR and Western blot.RESULTS:The mRNA level of Egr-1 in cerebral cortex of HDC-KO mice was significantly lower than that in WT mice, while exogenous histamine induced the mRNA expression of Egr-1 in HDC-KO mice.In cultured astrocytes, histamine induced the mRNA expression of Egr-1.The maximum increase in the mRNA level of Egr-1 was produced by histamine at concentration of 10 -5 mol/L.In addition, histamine-induced Egr-1 mRNA accumulation peaked at 30 min after commencing stimulation, while histamine significantly increased Egr-1 protein expression at 60 min.Furthermore, histamine-induced Egr-1 expression was inhibited by H1 receptor antagonist but not H2 receptor antagonist.CONCLUSION:Histamine up-regulates the Egr-1 expression in cerebral cortex and cultured astrocytes, which may attribute to H1 receptor activation.
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AIM: To determine the effect of endogenous histamine on transient forebrain ischemia-induced neuronal injury at the late phase of reperfusion using histidine decarboxylase knockout ( HDC-KO) mice.METHODS:Wild-type (WT) and HDC-KO mice were subjected to bilateral common carotid artery occlusion for 30 min followed by 3 d or 15 d of reperfusion.At different time points after reperfusion, the body weight, mortality rate, learning and memory in fear conditioning test and hippocampal CA 1 neuronal density were evaluated .RESULTS: At 1 d after reperfusion , the body weight loss was observed in both WT and HDC-KO mice.At 4 d, 5 d, 6 d and 7 d after reperfusion, the increment in the body weight of the HDC-KO mice was significantly smaller than that of the WT mice .During the period between 8 d and 14 d after reperfusion, the mortality rate of the HDC-KO mice was higher than that of the WT mice (P<0.05).At 14 d after reperfusion , the HDC-KO mice exhibited more aggravated deficits in contextual and cue memory compared with the WT mice.Correspondingly , a more severe CA1 neuronal injury in the HDC-KO mice than that in the WT mice was ob-served at 15 d but not at 3 d after reperfusion (P<0.05).CONCLUSION:Endogenous histamine may attenuate learn-ing/memory deficits and neuronal injury at the late phase of ischemia /reperfusion.However, the involved mechanisms need to be further investigated .
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AIM: To study the effect and mechanism of BCG on human nature killer cells. METHODS: PBMC or purified NK cells were isolated from normal human peripheral blood with negative anti-Mycobacterium tuberculosis antibody and cultured with BCG, IL-12, BCG plus IL-12 and BCG plus anti-IL-12Rβ1 mAb (2B10), respectively. The levels of IFN-γ and IL-12p40 in the culture supernatants were measured by ELISA. The frequency of IFN-γ and granzyme B producing cells were analyzed by ELISpot. The cytolytic activity was detected by MTT reduction assay. The surface expression of IL-12Rβ1 on NK cells was detected by flow cytometry. RESULTS: BCG significantly induced IFN-γ production by PBMC in a dose-dependent manner. When PBMC was stimulated with BCG, the frequency of granzyme B producing cells was higher than that in unstimulated PBMC (P0.05). BCG induced IL-12 production by PBMC in a dose-dependent manner and enhanced IL-12Rβ1 expression on different subsets of NK cells. Blocking the effect of IL-12 by anti-IL-12Rβ1 mAb (2B10) inhibited BCG-induced IFN-γ production and granzyme B releasing by PBMC. CONCLUSION: BCG can indirectly promote biologic activity of NK cells and the production of endogenous IL-12 combined with up-regulation IL-12Rβ1 expression on the surface of NK cells is a part of the mechanisms of IL-12 on human NK cells.
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Objective:To elucidate the characterization of antigen-specific memory T cells from PPD~+ individuals after stimulation with BCG in vitro.Methods:PBMCs were isolated from PPD~ -/+ normal human peripheral blood and stimulated with BCG. The level of IFN-? in the culture supernatants was assayed by ELISA and the frequency of IFN-?-producinging cells was detected by ELISPOT. The subsets and frequency of cytokine-producing cells were determined at a single cell level by flow cytometry.Results:After stimulation with BCG, PBMCs from PPD~+ but not PPD~- individuals produced significantly high levels of IFN-? in culture supernatants detected by ELISA(P
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Objective:To evaluate the role of IL-23 in the production of IFN-?, cell subsets and regulation by human peripheral blood mononuclear cells(PBMCs).Methods:PBMCs were isolated from normal human peripheral blood and cultured with IL-23 in different culture conditions. The level of IFN-? in the culture supernatants was examined by ELISA. The subsets and frequency of IFN-?-producing cells were examined at a single cell level by flow cytometry.Results:IL-23 could directly induce IFN-? production by PBMCs and have synergistic effect with IL-2 on the induction of IFN-? production in a dose dependent manner. The data from Flow cytometric analysis indicated that IL-23 could induce IFN-? expression by CD3~-CD56~+NK cells but not CD3~+CD4~+ and CD8~+T cells. It is noted that IL-23 predominantly induced IFN-? expression by NK cells with high expression of CD56 molecules. Addition of Th2 cytokines or anti-IL-12R?1 mAbs resulted in the inhibition of IL-23-inducing IFN-? production.Conclusion:IL-23 can directly induce IFN-? production by PBMCs. The induction of IFN-? induced by IL-23 can be suppressed by Th2 cytokines and anti-IL-12R?1 mAbs. The data indicated that Th2 cytokines and anti-IL-12R?1 mAbs might have the potential application for the treatment of IL-23-mediated autoimmune diseases.