Purinergic alarmin signaling in acute and chronic viral Infections

针对病毒病原体的细胞免疫反应是一个严格调控的过程，由细胞内和细胞外信号协调，以维持抗病毒免疫和组织破坏性免疫病理学之间的平衡。由于复杂的细胞-细胞相互作用和时空受限的过程，驱动适应性和先天免疫反应的机制仍然不完全清楚。然而，识别新的调控因子对于靶向治疗的设计是至关重要的。近年来，我们和其他人已经表明，警报因子，特别是细胞因子白细胞介素33(IL-33)，在急性和慢性炎症的诱导和调节中发挥着核心作用。IL-33在坏死性细胞死亡后释放，同样可以促进效应性T细胞的活性或调节性T细胞的抑制和组织再生特性。除了被广泛研究的IL-33、IL-1α或S100蛋白外，代谢产物如嘌呤-三磷酸腺苷(ATP)已成为炎症部位组织损伤的关键指标和T细胞反应的关键调节因子。三磷酸腺苷可以与T细胞上的嘌呤能受体结合，从而诱导剂量依赖性的细胞内钙离子内流。这反过来微调了许多细胞内的信号通路，并可以极大地影响T细胞的新陈代谢和活性。我们研究了P2X家族各种嘌呤能受体的表达模式，并确定了由激活的抗病毒T细胞选择性表达并由炎症信号诱导的新的候选受体。因此，我们建议研究ATP-P2X信号在免疫动态平衡和淋巴细胞性脉络膜脑膜炎病毒(LCMV)急性和慢性病毒感染过程中的作用。利用新产生的敲除和敲入小鼠品系，我们将研究ATP-P2X信号对功能性T细胞扩增、分化、效应功能的获得和T细胞耗竭的内在需求。此外，这些实验将得到最先进的下一代测序方法和代谢分析的补充，以评估有缺陷的ATP传感的分子后果。最后，我们将研究已建立的ATP-P2X信号通路的药物抑制剂在预防病毒诱导的免疫病理中的治疗潜力，旨在为临床前研究铺平道路。

The cellular immune reaction against viral pathogens is a tightly regulated process orchestrated by intra- and extracellular cues to maintain a balance between antiviral immunity and tissue-destructive immunopathology. Owing to complex cell-cell interactions and spatiotemporally restricted processes, the mechanisms driving adaptive and innate immune responses remain incompletely understood. Yet, the identification of novel regulators is critical for the design of targeted therapeutics.In recent years, we and others have shown that alarmins, in particular the cytokine interleukin-33 (IL-33), play a central role in both induction and regulation of acute and chronic inflammation. Released upon necrotic cell death, IL-33 can equally promote effector T cell activity or suppressive and tissue-regenerative properties of regulatory T cells. Besides the well-studied alarmins IL-33, IL-1alpha or S100 proteins, metabolites such as the purine adenosine-triphosphate (ATP) have emerged as critical indicators of tissue damage at sites of inflammation and key regulators of T cell responses. ATP can bind to purinergic receptors on T cells and thereby induce a dose-dependent cellular Ca2+ ion influx. This in turn fine-tunes a multitude of intracellular signaling pathways and can drastically affect T cell metabolism and activity.We have studied the expression patterns of various purinergic receptors of the P2X family and identified novel candidates that are selectively expressed by activated antiviral T cells and induced by inflammatory signals. Hence, we here propose to study the role of ATP-P2X signaling in immune homeostasis and during acute and chronic viral infection with lymphocytic choriomeningitis virus (LCMV). Using newly generated knock-out and knock-in mouse lines, we will study the T cell-intrinsic requirement of ATP-P2X signaling for functional T cell expansion, differentiation, acquisition of effector functions and T cell exhaustion. Further, these experiments will be complemented by state-of-the-art next generation sequencing approaches and metabolic assays to assess the molecular consequences of defective ATP sensing. Lastly, we will investigate the therapeutic potential of established pharmacologic inhibitors of ATP-P2X signaling in preventing virus-induced immunopathology with the aim to pave the way for pre-clinical studies.