Mitochondrial AntiViral Signaling Protein, IRF1, and Ischemic AKI

摘要 我们发现了一种新的“缺血性AKI”MAVS途径，可加重缺血性急性肾损伤 （阿基）。缺血性阿基期间产生的活性氧（ROS）激活MAVS（线粒体抗病毒药物） 信号蛋白），MAVS激活IRF 1（干扰素调节因子1），IRF 1刺激产生 适应不良-干扰素（α干扰素）。 缺血/再灌注<$ROS <$MAVS激活<$IRF1基因激活<$<$-IFN 产生<$IFN <$$>受体结扎<$肾损伤。 上述途径得到了我们的体内和体外数据的支持。转基因敲除MAVS、IRF 1或 IFN受体证实了体内缺血性阿基过程中事件顺序。MAVS的siRNA敲低，或 IRF 1在ROS刺激的体外肾小管上皮细胞中证实了该序列。 MAVS和干扰素是在我们的工作之前，只知道参与抗病毒的分子。 应答尽管“抗病毒”MAVS途径是由细胞质病毒核酸触发的，但我们的研究发现， “缺血-AKI”MAVS-途径由缺血性阿基期间产生的ROS触发。我们还提出了新的 线粒体和过氧化物酶体在缺血性阿基中的作用（见目的I）。 我们发现，在“缺血-AKI”MAVS途径中的关键中间步骤是IRF 1的激活， 基因然后IRF 1激活<$-IFN。与其在缺血性阿基中的重要性相反，IRF 1不是一个关键的 在宿主防御大多数病毒感染中起中间作用。因此，我们把这项建议的重点放在 了解IRF 1的激活。这种理解将导致新的疗法，将阻断 通过抑制IRF 1基因激活，“缺血-AKI”MAVS-通路的适应不良效应， 对抗病毒应答的负面影响，其中大多数是IRF 1独立的。 目的I：缺血性AKI是否通过“过氧化物酶体”或“免疫抑制剂”激活IRF 1基因和下游的干扰素？ “线粒体”MAVS途径？在我们的新的“缺血-AKI”MAVS-通路中的关键调节蛋白是 MAVS MAVS具有C末端跨膜基序，其嵌入过氧化物酶体和线粒体中， 膜。在应对病毒时，过氧化物酶体与线粒体MAVS激活不同的基因。 前者是大多数病毒感染过程中的次要成分。病毒过氧化物酶体，而不是线粒体， MAVS途径与“缺血-AKI”MAVS途径共享转录因子IRF 1的使用。我们 将确定“缺血-AKI”MAVS途径是否使用过氧化物酶体MAVS。我们将确定是否具体 激活或抑制线粒体对过氧化物酶体途径抑制IRF 1激活。 目的II：转录因子的独特组合是否在“缺血-AKI”MAVS中激活IRF 1- pathway？我们将检验“缺血-AKI”和“抗病毒”MAVS-通路激活不同细胞的假设。 转录因子这可以解释为什么前者激活IRF 1，而后者不激活。

Abstract We have discovered a novel "ischemic-AKI" MAVS-pathway that exacerbates ischemic acute kidney injury (AKI). Reactive oxygen species (ROS) produced during ischemic AKI activate MAVS (Mitochondria Anti-Viral Signaling protein), MAVS activates IRF1 (interferon regulatory factor 1), and IRF1 stimulates the production of maladaptive ¿-IFNs (alpha interferons). Ischemia/ reperfusion ¿ ROS ¿ MAVS activation ¿ activation of IRF1 gene ¿ ¿-IFN production ¿ IFN¿¿ receptor ligation ¿ renal injury. The above pathway is supported by our in vivo and in vitro data. Transgenic knockout of MAVS, IRF1, or the IFN receptor confirm this sequence of events during ischemic AKI in vivo. siRNA knockdown of MAVS, or IRF1 confirm the sequence in ROS-stimulated renal tubular epithelia in vitro. MAVS, and ¿-IFNs are molecules that, previous to our work, were only known to participate in anti-viral responses. Whereas the "anti-viral" MAVS-pathways are triggered by cytoplasmic viral nucleic acids, our "ischemic-AKI" MAVS-pathway is triggered by ROS generated during ischemic AKI. We also propose novel roles for mitochondria and peroxisomes in ischemic AKI (see Aim I). We found that a critical intermediate step in the "ischemic-AKI" MAVS-pathway is activation of the IRF1 gene. IRF1 then activates ¿-IFNs. In contrast to its importance in ischemic AKI, IRF1 is not a critical intermediate in the host defense against most viral infections. Therefore, we focus this proposal on understanding the activation of IRF1. This understanding will lead to new therapies that would interdict the maladaptive effects of the "ischemic-AKI" MAVS-pathway by inhibiting IRF1 gene activation, without a major negative impact on anti-viral responses most of which are IRF1 independent. Aim I: Does ischemic-AKI activate the IRF1 gene, and downstream ¿-IFNs, via the "peroxisomal" or "mitochondrial" MAVS-pathways? The key regulatory protein in our novel "ischemic-AKI" MAVS-pathway is MAVS. MAVS has a C-terminal transmembrane motif that embeds it into peroxisomal and mitochondrial membranes. In response to viruses, the peroxisomal versus mitochondrial MAVS activate different genes. The former is a minor component during most viral infections. The viral peroxisomal, but not the mitochondrial, MAVS pathway shares the use of the transcription factor IRF1 with the "ischemic-AKI" MAVS-pathway. We will determine if the "ischemic-AKI" MAVS-pathway uses peroxisomal MAVS. We will determine if specifically activating or inhibiting the mitochondrial versus peroxisomal pathways inhibits IRF1 activation. Aim II: Does a unique combination of transcription factors activate IRF1 in the "ischemic-AKI" MAVS- pathway? We will test the hypothesis that the "ischemic-AKI" and "anti-viral" MAVS-pathway activate different transcription factors. This would explain why the former activates IRF1, while the latter does not.