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近日,我所翁長(zhǎng)江團(tuán)隊(duì)在天然免疫研究上取得新進(jìn)展,相關(guān)研究成果以“DDX19 inhibits type I interferon production by disrupting TBK1-IKKε-IRF3 interactions and promoting TBK1 and IKKε degradation”為題于1月29日在線發(fā)表《Cell Reports》上。該研究發(fā)現(xiàn)DExD/H-box解旋酶家族成員DDX19分子是RIG-I樣受體(RLRs)介導(dǎo)Ⅰ型干擾素產(chǎn)生的負(fù)調(diào)控分子,闡明了DDX19抑制Ⅰ型干擾素產(chǎn)生的兩種作用機(jī)制。這是該團(tuán)隊(duì)在發(fā)現(xiàn)DDX19作為病毒RNA受體參與NLRP3炎癥反應(yīng)之后取得的又一重要研究進(jìn)展。
天然免疫反應(yīng)(innate immune response)是宿主通過(guò)識(shí)別“自我”與“非我”,抵抗病原微生物入侵的第一道防線。其中,RLRs信號(hào)通路是機(jī)體識(shí)別病毒感染、抑制及清除病毒的重要信號(hào)通路。DExD/H-box解旋酶家族成員RIG-I (DDX58)、MDA5、LGP-2 (DHX58)等在RLRs信號(hào)通路調(diào)控中發(fā)揮重要作用。
本研究中,科研人員分別在傳代細(xì)胞系、DDX19過(guò)表達(dá)穩(wěn)定細(xì)胞株、DDX19基因敲除細(xì)胞株和DDX19基因敲除小鼠上證明了DDX19是RLRs信號(hào)通路的負(fù)調(diào)節(jié)分子。深入研究發(fā)現(xiàn),DDX19通過(guò)破壞TBK1-IKKε-IRF3復(fù)合物形成,抑制IRF3的磷酸化,并招募Lamtor2蛋白,促進(jìn)TBK1和IKKε的降解,最終抑制Ⅰ型干擾素的產(chǎn)生。

本研究是在國(guó)家自然科學(xué)基金項(xiàng)目(31640083和31300139)的資助下完成的。博士研究生張昆麗和碩士研究生張?jiān)鍨檎撐墓餐谝蛔髡?,黃麗副研究員和翁長(zhǎng)江研究員為共同通訊作者。(張昆麗 黃麗)
SUMMARY
DExD/H-box helicase members are key receptors for recognizing viral nucleic acids and they regulate RLR-mediated type I interferon (IFN) production. Here we report that the DExD/H-box helicase family member DDX19 is a negative regulator of type I IFN production. Ectopic expression of DDX19 suppressed poly(I:C)- and Sendai virus-induced type I IFN production, whereas knockdown of DDX19 expression enhanced type I IFN production. Mechanistically, DDX19 inhibited TBK1- and IKKε-mediated phosphorylation of IRF3 by disrupting the interaction between TBK1 or IKKε and IRF3. Additionally, DDX19 recruited Lamtor2 and then formed the TBK1-IKKε-Lamtor2-DDX19-IRF3 complex to suppress IFN production by promoting TBK1 and IKKε degradation. We generated Ddx19 knockout mice using TALENs and found that Ddx19 deficiency in vivo augmented type I IFN production, resulting in suppression of encephalomyocarditis virus replication. These data show that DDX19 is an important negative regulator of RLR-mediated type I IFN production.
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