权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Mechanisms of Fusion of Macrophages Induced by 1 ,25(OH)_2D_3

1 ,25(OH)_2D_3诱导巨噬细胞融合的机制

基本信息

批准号：
60440086
负责人：
SUDA Tatsuo
金额：
$ 9.98万
依托单位：
Showa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1987
项目状态：
已结题

项目摘要

We have reported that 1<alpha>,25-dihydroxyvitamin D_3 [1<alpha>,25(OH)_2D_3] directly induces fusion of mouse alveolar macrophages at a very high rate (circa 70-80%) by a mechanism involving protein synthesis (Proc. Natl. Acad. Sci. USA 80:5583,1983; FEBS Letters 174:61,1984). While examining further the mechanism of the 1<alpha>,25(OH)_2D_3-induced fusion of macrophages, we found that polyamines are involved in this mechanism. Mouse alveolar macrophages incubated with 12 nM 1<alpha>,25(OH)_2D_3 began to fuse at 36 h and the fusion rate increased linearly up to 60 h. Addition of as much as 0.05 - 5 mM -difluoromethylornithine (<alpha>-DFMO), a specific inhibitor of ornithine decarboxylase, did not inhibit fusion appreciably, but addition of 0.05 - 5<mu>M methylglyoxal bis (guanylhydrazone) (MGBG), an inhibitor of S-adenosylmethionine decarboxylase, strikingly inhibited fusion. When macrophages were treated with both 12 nM 1<alpha>,25(OH)_2D2_3 and 5 <mu>M MGBG for the first 12 h and i … More ncubated further for 60 h in fresh medium containing 1<alpha>,25(OH)_2D_3, fusion was significantly inhibited, suggesting that the 1<alpha>,25(OH)_2D_3-induced synthesis of polyamines precedes fusion. The inhibition by MGBG of the 1<alpha>,25(OH)_2D_3-induced fusion was restored completely by adding 1 <mu>M spermidine or spermine or 100 M putrescine. None of the polyamines alone induced fusion. MGBG suppressed the 1<alpha>,25(OH)_2D_3-induced incorporation of [^3H]-leucine into the trichloroacetic acid-insoluble fraction in macrophages, but its inhibitory effect was restored completely by adding 1<mu> M spermidine. When macrophages were incubated with [^<14>C]-ornithine, the polyamine that accumulated most was [^<14>C]-spermidine. 1<alpha>,25(OH)_2D_3 further enhanced the accumulation of [^<14>C] putrescine and spermine was not appreciably altered by the 1<alpha>,25(OH)_2D_3 treatment. Adding MGBG almost completely suppressed the accumulation of [^<14>C]-spermidine and spermine, but it enhanced the accumulation of [^<14>C]-putrescine considerably. These results indicate that spermidine or spermine is an important intracellular mediator of the 1<alpha>,25(OH)_2D_3 action in inducing protein synthesis, which in turn somehow induces fusion of alvolar macrophages. Less

我们已经报道了1<alpha>，25-二羟基维生素D_3 [1<alpha>，25（OH）_2D_3]通过涉及蛋白质合成的机制以非常高的速率（约70-80%）直接诱导小鼠肺泡巨噬细胞的融合（Proc.Natl.Chem.2004）。Acad. Sci. USA 80：5583，1983; FEBS Letters 174：61，1984）。在进一步研究1<alpha>，25（OH）_2D_3诱导巨噬细胞融合的机制时，我们发现多胺参与了这一机制。小鼠肺泡巨噬细胞与12 nM 1<alpha>，25（OH）_2D_3共孵育36 h后开始融合，融合率线性增加，直至60 h。添加多达0.05 - 5 mM -二氟甲基鸟氨酸（<alpha>-DFMO），一种特异性的鸟氨酸脱羧酶抑制剂，并没有明显抑制融合，但添加0.05 - 5 <mu>M甲基乙二醛双（鸟苷酰腙）（MGBG），一种S-腺苷甲硫氨酸脱羧酶抑制剂，显着抑制融合。当巨噬细胞用12 nM 1<alpha>，25（OH）_2D2_3和5 <mu>M MGBG处理前12小时， ...更多信息在含1，25（OH）_2D_3的新鲜培养基中继续孵育60 h<alpha>，融合受到明显抑制，表明1<alpha>，25（OH）_2D_3诱导的多胺合成先于融合。MGBG对1<alpha>，25（OH）_2D_3诱导的融合的抑制作用可在加入1 <mu>M精脒或精胺或100 M腐胺后完全恢复。没有单独的多胺诱导融合。MGBG抑制1<alpha>，25（OH）_2D_3诱导的[^3 H]-亮氨酸掺入巨噬细胞三氯乙酸不溶部分，但加入1 M亚精胺后，其抑制作用完全恢复<mu>。当巨噬细胞与[^<14>C]-鸟氨酸孵育时，积累最多的多胺是[^<14>C]-亚精胺。1<alpha>，25（OH）_2D_3处理进一步促进[13 <14>C]腐胺的积累，而精胺没有明显改变<alpha>。添加MGBG几乎完全抑制了[^<14>C]-亚精胺和精胺的积累，但显著促进了[^<14>C]-腐胺的积累。这些结果表明，精脒或精胺是1<alpha>，25（OH）_2D_3诱导蛋白质合成的重要细胞内介质，而蛋白质合成又以某种方式诱导巨噬细胞融合。少