Noncanonical STAT1 phosphorylation expands its transcriptional activity into promoting LPS-induced IL-6 and IL-12p40 production
Noncanonical STAT1 phosphorylation expands its transcriptional activity into promoting LPS-induced IL-6 and IL-12p40 production
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DOI：
10.1126/scisignal.aay0574
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发表时间：
2020-03-24
影响因子：
7.3
通讯作者：
Kishimoto, Tadamitsu
中科院分区：
文献类型：
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作者：
Metwally, Hozaifa;Tanaka, Toshio;Kishimoto, Tadamitsu
脂多糖（LPS）诱导的Toll样受体4（TLR 4）的内吞作用是产生干扰素-β（IFN-β）的重要步骤，IFN-β通过在Tyr（701）处磷酸化的STAT 1激活抗病毒应答基因的转录。在这里，我们发现STAT 1调节TLR 4胞吞作用下游的促炎细胞因子的产生，而不依赖于IFN-β信号和关键的促炎调节因子NF-κ B。在人巨噬细胞中，TLR 4内吞激活了STAT 1在Thr（749）的非经典磷酸化，随后通过不同的机制促进了白细胞介素-6（IL-6）和IL-12 p40的产生。在Thr（749）处磷酸化的STAT 1激活编码ARID 5A的基因的表达，其稳定IL 6 mRNA。此外，在Thr 749处磷酸化的STAT 1直接增强编码IL-12 p40（IL 12 B）的基因的转录。Thr 749的磷酸化不影响STAT 1的核转位，而是促进STAT 1与ARID 5A和IL 12 B启动子区的非典型DNA基序（5 '-TTTGANNC-3'）的结合。TLR 4的内吞作用诱导激酶TBK 1和IKK β之间形成复合物，其介导STAT 1在Thr（749）的磷酸化。我们的数据表明，非典型的磷酸化反应LPS赋予STAT 1与不同的DNA结合和基因调控特性，促进IL 12 B的表达和IL 6 mRNA的稳定。因此，我们的研究提供了一个潜在的机制如何TLR 4内吞可能调节促炎细胞因子的产生。
The lipopolysaccharide (LPS)-induced endocytosis of Toll-like receptor 4 (TLR4) is an essential step in the production of interferon-beta (IFN-beta), which activates the transcription of antiviral response genes by STAT1 phosphorylated at Tyr(701). Here, we showed that STAT1 regulated proinflammatory cytokine production downstream of TLR4 endocytosis independently of IFN-beta signaling and the key proinflammatory regulator NF-kappa B. In human macrophages, TLR4 endocytosis activated a noncanonical phosphorylation of STAT1 at Thr(749), which subsequently promoted the production of interleukin-6 (IL-6) and IL-12p40 through distinct mechanisms. STAT1 phosphorylated at Thr(749) activated the expression of the gene encoding ARID5A, which stabilizes IL6 mRNA. Moreover, STAT1 phosphorylated at Thr749 directly enhanced transcription of the gene encoding IL-12p40 (IL12B). Instead of affecting STAT1 nuclear translocation, phosphorylation of Thr749 facilitated the binding of STAT1 to a noncanonical DNA motif (5'-TTTGANNC-3') in the promoter regions of ARID5A and IL12B. The endocytosis of TLR4 induced the formation of a complex between the kinases TBK1 and IKK beta, which mediated the phosphorylation of STAT1 at Thr(749). Our data suggest that noncanonical phosphorylation in response to LPS confers STAT1 with distinct DNA binding and gene-regulatory properties that promote both IL12B expression and IL6 mRNA stabilization. Thus, our study provides a potential mechanism for how TLR4 endocytosis might regulate proinflammatory cytokine production.