Two novel threonine phosphorylations of STAT2 impact inflammatory responses to bacterial infection.

项目摘要 驱动对I型干扰素（IFN-I）的应答的主要转录因子是ISGF 3，其由酪氨酸- 磷酸化STAT 1和2以及DNA结合蛋白IRF 9。T387细胞上STAT 2的苏氨酸磷酸化 并且T404深刻地影响IFN-1驱动基因表达和依赖性生物学功能的能力。 此外，STAT 2缺乏酪氨酸磷酸化（U-STAT 2）增强NF-κB靶基因的表达 其编码几种趋化因子和促炎细胞因子（例如IL-6），并且还抑制 IFN-γ激活STAT 1的酪氨酸磷酸化和下游基因表达。这些非典型的 U-STAT 2的功能也通过其在T387和T404上的磷酸化来调节。戏剧性的效果被认为是与 在这两个位点都携带纯合T-A突变的小鼠。T403 A小鼠对干扰素-Ⅰ的应答缺陷 导致他们对水泡性口炎病毒（VSV）或单纯疱疹病毒（HSV）感染高度敏感。 (The小鼠的编号为T386和T403。T403 A小鼠对炎性刺激的反应也大大增加。 暴露了溃疡性结肠炎是一种慢性疾病，其中结肠内膜发炎并发展 溃疡在葡聚糖硫酸钠（DSS）诱导的溃疡性结肠炎模型中，T403 A/T403 A基因敲入小鼠，其中 该位点不能被磷酸化，对DSS诱导的死亡率比WT/WT小鼠敏感得多， 减肥.脓毒症和脓毒性休克是非冠状动脉重症监护病房的主要死亡原因。我们有 显示脓毒症中的免疫应答从早期/高炎症转变为晚期/低炎症， 免疫抑制表型与涉及肺、心脏、肾和 肝脏此外，长时间的低炎症与受损的病原体清除有关。与野生相比- 型对照，保护T403 A/T403 A小鼠免受，并且使T386 A/T386 A小鼠对用 脂多糖（LPS），脓毒性休克的诱导剂，以及IFN-Ⅰ和IL-6表达的诱导被抑制， T403 A/T403 A小鼠。我们的主要目标如下。1)我们想详细了解磷酸化 STAT 2在这两个苏氨酸残基上的表达受到调节（哪些激活信号？哪些激酶？这 磷酸酶？）。2)我们希望详细了解STAT 2如何影响促炎机制 苏氨酸磷酸化3)我们希望利用这些信息来开发新的治疗方法， 肠道细菌引起的炎症反应，尤其是结肠炎症和败血性休克。我们 预期我们可以更好地理解STAT 2的苏氨酸磷酸化在 炎症和感染的新的治疗方法，以及发现新的方法， 改善细菌诱导的急性炎症也可能有助于其他炎症状况。

Project Summary The major transcription factor that drives responses to type I interferon (IFN-I) is ISGF3, comprised of tyrosine- phosphorylated STATs 1 and 2 and the DNA binding protein IRF9. The threonine phosphorylation of STAT2 on T387 and T404 profoundly affects the ability of IFN-I to drive gene expression and dependent biological functions. Furthermore, STAT2 lacking tyrosine phosphorylation (U-STAT2) enhances the expression of NF-κB target genes that encode several chemokines and pro-inflammatory cytokines (for example, IL-6), and also inhibits the ability of IFN-γ to activate the tyrosine phosphorylation of STAT1 and downstream gene expression. These non-canonical functions of U-STAT2 are also regulated by its phosphorylation on T387 and T404. Dramatic effects are seen with mice carrying homozygous T-A mutations at each of these two sites. The defective response to IFN-I in T403A mice causes them to be highly susceptible to infections with vesicular stomatitis virus (VSV) or Herpes Simplex virus (HSV). (The numbers for mice are T386 and T403.) The responses of T403A mice to inflammatory stimuli are also greatly compromised. Ulcerative colitis is a chronic disease in which the lining of the colon becomes inflamed and develops ulcers. In the dextran sulfate sodium (DSS)-induced model of ulcerative colitis, T403A/T403A knockin mice, in which this site cannot be phosphorylated, are very much more sensitive than WT/WT mice to DSS-induced mortality and weight loss. Sepsis and septic shock are the leading causes of death in non-coronary intensive care units. We have shown that the immune response in sepsis transitions from an early/hyper-inflammatory to a late/hypo-inflammatory, immunosuppressive phenotype that is associated with multiple organ dysfunction involving lung, heart, kidney and liver. Furthermore, prolonged hypo-inflammation is associated with impaired pathogen clearance. Compared with wild- type controls, T403A/T403A mice are protected from, and T386A/T386A mice are sensitized to challenge with lipopolysaccharide (LPS), an inducer of septic shock, and the induction of IFN-I and IL-6 expression is suppressed in T403A/T403A mice. Our primary objectives follow. 1) We want to understand in detail how the phosphorylation of STAT2 on these two threonine residues is regulated (which activating signals? which kinases? which phosphatases?). 2) We want to understand in detail how pro-inflammatory mechanisms are affected by STAT2 threonine phosphorylation. 3) We want to use this information to develop novel therapeutic approaches to inflammatory responses to commensal bacteria, especially colonic inflammation and septic shock. We anticipate that we can parlay improved understanding of the roles of threonine phosphorylation of STAT2 in inflammation and infection into novel therapeutic approaches, and that the discovery of novel approaches to ameliorate bacterially-induced acute inflammation may also be helpful in other inflammatory conditions.