Astrocytes are Very Sensitive to Develop Innate Immune Responses to Lipid-Carried Short Interfering RNA
Astrocytes are Very Sensitive to Develop Innate Immune Responses to Lipid-Carried Short Interfering RNA
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DOI：
10.1002/glia.20738
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发表时间：
2009-01-01
期刊：
影响因子：
6.2
通讯作者：
Planas, Anna M.
中科院分区：
文献类型：
--
作者：
Gorina, Roser;Santalucia, Tomas;Planas, Anna M.
短干扰RNA(SiRNA)通过RNA干扰(RNAi)抑制特定蛋白质的合成。然而，siRNA可以诱导由免疫系统细胞中的Toll样受体(Toll-like Receptor，TLRs)介导的先天性免疫反应。在这里，我们试图评估siRNA是否可以在神经胶质细胞中诱导这样的反应。我们研究了不同的siRNA序列与脂类(低聚半乳糖胺)制备的效果。脂质siRNA可诱导不同程度的非特异性沉默效应，如STAT1和COX-2的表达增加以及IL-6和IP-10的释放。这是通过核苷2‘-O-甲基化对siRNA进行化学修饰来防止的，而不会损害特定的基因沉默。脂质-siRNA也能在纯化的星形胶质细胞中诱导非特异性反应，但不能在小胶质细胞或3T3细胞中诱导。小胶质细胞和纯化的星形胶质细胞分别表达TLR7和TLR3mRNA。因此，TLR3激动剂Poly(I：C)(PIC)在原代和纯化的星形胶质细胞中诱导的干扰素-β的释放高于小胶质细胞。作为siRNA，PIC诱导IP-10、STAT1、VCAM-1和COX-2的表达，并增加TLR3mRNA的表达。抑制TLR3或TLR7的表达以及PKR抑制剂2-氨基嘌呤可减弱脂类siRNA对纯化星形胶质细胞的作用。此外，脂质siRNA可诱导RIG-1的表达。相反，去脂siRNA不进入星形胶质细胞，不沉默基因表达，也不诱导STAT1或COX-2。结果表明，在星形胶质细胞中，脂类siRNA诱导的先天免疫反应至少部分是通过依赖TLR7、TLR3和解旋酶的细胞内机制来介导的。(C)2008年Wiley-Liss，Inc.
Short interfering RNA (siRNA) inhibits the synthesis of specific proteins through RNA interference (RNAi). However, siRNA can induce innate immune responses that are mediated by toll-like receptors (TLRs) in cells of the immune system. Here, we sought to evaluate whether siRNA can induce such responses in glial cells. We examined the effects of various siRNA sequences prepared with lipids (oligofectamine). Lipid-siRNA induced variable degrees of silencing-independent nonspecific effects, e.g. increased Stat1 and Cox-2 expression and release of IL-6 and IP-10 in primary astroglia. This was prevented through chemical modification of siRNA by nucleoside 2'-O-methylation, without impairing specific gene silencing. Lipid-siRNA also induced nonspecific responses in purified astroglia, but not in microglia, or 3T3 cells. The highest TLR7 and TLR3 mRNA expression was found in microglia and purified astroglia, respectively. Accordingly, the TLR3 agonist poly(I:C) (PIC) induced higher release of IFN-beta in primary and purified astroglia than in microglia. As siRNA, PIC induced IP-10, Stat1, VCAM-1, and Cox-2 and increased TLR3 mRNA expression. The effects of lipid-siRNA in purified astrocytes were attenuated after silencing TLR3 or TLR7 expression, and by the PKR inhibitor 2-aminopurine. Furthermore, lipid-siRNA induced the expression of RIG-1. In contrast, siRNA devoid of lipids did not enter the astrocytes, did not silence gene expression, and did not induce Stat1 or Cox-2, The results show that, in astroglia, lipid-siRNA induces innate immune responses that are mediated, at least in part, by intracellular mechanism dependent on TLR7, TLR3, and helicases. (C) 2008 Wiley-Liss, Inc.