The RelA(p65) subunit of NF-κB is essential for inhibiting double-stranded RNA-induced cytotoxicity
The RelA(p65) subunit of NF-κB is essential for inhibiting double-stranded RNA-induced cytotoxicity
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DOI：
10.1074/jbc.m006647200
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发表时间：
2001-01-12
影响因子：
4.8
通讯作者：
Beg, AA
中科院分区：
文献类型：
--
作者：
Li, M;Shillinglaw, W;Beg, AA
病毒感染过程中产生的双链RNA（dsRNA）分子可以启动宿主的抗病毒反应，以限制进一步感染。这种反应涉及通过dsRNA活化蛋白激酶（PKR）和NF-κ B转录因子诱导抗病毒基因表达。此外，dsRNA还可以通过不完全理解的机制诱导细胞凋亡，该机制可能有助于进一步限制病毒复制。在这里，我们证明了NF-κ B的RelA亚基在抑制dsRNA诱导的细胞死亡中的新作用，dsRNA处理导致来自RelA-/-小鼠但不是来自RelA+/-小鼠的小鼠胚胎成纤维细胞（MEF）中的半胱天冬酶3活化和凋亡形态转化。这种dsRNA诱导的杀伤可以通过PKR的显性负突变体或野生型RelA的表达来抑制。有趣的是，在RelA-/- MEFs的dsRNA处理后激活的半胱天冬酶3对于凋亡性核变化是必需的，但对于细胞毒性是必需的。更广泛的特异性半胱天冬酶抑制剂也不能抑制dsRNA诱导的细胞毒性，这表明半胱天冬酶活化对于MEFs中dsRNA诱导的细胞死亡不是必需的。然而，半胱天冬酶3和活性氧产生的组合抑制导致dsRNA诱导的细胞毒性的完全抑制。这些结果表明NF-κ B在保护细胞免受dsRNA诱导的凋亡中起重要作用，并表明NF-κ B可抑制半胱天冬酶依赖性和活性氧依赖性细胞毒性途径。
Double-stranded RNA (dsRNA) molecules generated during virus infection can initiate a host antiviral response to limit further infection. Such a response involves induction of antiviral gene expression by the dsRNA-activated protein kinase (PKR) and the NF-kappaB transcription factor. In addition, dsRNA can also induce apoptosis by an incompletely understood mechanism that may servo to further limit viral replication. Here we demonstrate a novel role for the RelA subunit of NF-KB in inhibiting dsRNA-induced cell death, dsRNA treatment resulted in caspase 3 activation and apoptotic morphological transformations in mouse embryonic fibroblasts (MEFs) derived from RelA-/- mice but not from RelA+/- mice. Such dsRNA-induced killing could be inhibited by expression of either a dominant-negative mutant of PKR or wild-type RelA Interestingly, caspase 3 activated following dsRNA treatment of RelA-/- MEFs was essential for apoptotic nuclear changes but dispensable for cytotoxicity. A broader specificity caspase inhibitor was also unable to inhibit dsRNA-induced cytotoxicity, suggesting that caspase activation is not essential for the induction of cell death by dsRNA in MEFs. However, combined inhibition of caspase 3 and reactive oxygen species production resulted in complete inhibition of dsRNA-induced cytotoxicity. These results demonstrate an essential role for NF-kappaB in protecting cells from dsRNA-induced apoptosis and suggest that NF-kappaB may inhibit both caspase-dependent and reactive oxygen species-dependent cytotoxic pathways.