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Cell-intrinsic role of caspase-1 in regulating antigen-specific CD8+ T cell responses

Caspase-1 在调节抗原特异性 CD8 T 细胞反应中的细胞内在作用

基本信息

批准号：
10171780
负责人：
Mehul Shamal Suthar
金额：
$ 21.74万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-06-01 至 2023-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10171780
关键词：
Acute Adaptor Signaling Protein Address Adoptive Transfer Anatomy Antigens Antiviral Agents Bioenergetics Biological Assay Brain CASP1 gene CD28 gene CD3 Antigens CD8-Positive T-Lymphocytes Caspase Cell physiology Cells Cleaved cell Complex Consequentialism Cues Cytosol Encephalitis Enzyme Precursors Epidemic Gene Expression Profiling Homing Immunity Immunologics In Vitro Infection Inflammasome Inflammation Inflammatory Interleukin-1 beta Interleukin-18 Kinetics Link Mediating Metabolism Mitochondria Modeling Molecular Neuraxis Neuronal Injury Neurons Oxidative Phosphorylation Phase Play Production Reactive Oxygen Species Receptor Signaling Regulation Reporting Resolution Respiration Role Signal Transduction Skin Spleen T cell response T memory cell T-Cell Activation T-Cell Receptor T-Lymphocyte Subsets Time Tissues Viral Virus Virus Diseases Virus Replication West Nile viral infection West Nile virus base cytokine in vitro Assay in vivo lymph nodes mosquito-borne mouse model neurotropic novel prevent protein complex

项目摘要

ABSTRACT Caspase-1 is an essential component of the inflammasome complex and is responsible for cleaving pro- inflammatory cytokines IL-1β and IL-18 and initiating pyroptosis through cleavage of Gasdermin D. Using a murine model of West Nile virus (WNV) infection, we and others have previously demonstrated the importance of inflammasome signaling for promoting IL-1β-mediated protective immunity. We have now extended these observations and discovered a novel, cell-intrinsic role for caspase-1 in regulating antigen-specific CD8+ T cells responses during WNV infection. The absence of CD8+ T cells leads to uncontrolled WNV replication and significant neuronal injury within the brain. To understand how environmental cues within the brain impact T cell responses during WNV infection, we performed transcriptional profiling on antigen-specific CD8+ T cells isolated from the spleen and brain at early and late times post-WNV infection. Through this analysis, we found that caspase-1, as well as other inflammasome signaling components, were enriched within brain-resident antigen- specific CD8+ T cells as compared to antigen-specific CD8+ T cells isolated from the spleen. We confirmed that active caspase-1 is more abundantly expressed within brain-resident CD8+ T cells as compared to splenic CD8+ T cells. Using a co-adoptive transfer model, we observed increased antigen-specific Casp1-/- CD8+ T cells as compared to WT CD8+ T cells within the spleen and brain during infection. Of note, CD8+ T cells are not infected by WNV, suggesting that the activation of caspase-1 is independent of virus infection. Next, we characterized caspase-1 function in vitro using an in vitro T cell receptor (TCR) stimulation assay and found that caspase-1 is autoproteolytically cleaved following CD3/CD28 stimulation. Moreover, we found that ASC, but not NLRP3 or IL- 1β, is expressed in naïve and stimulated CD8+ T cells. Lastly, recent studies have linked caspase-1 with mitochondrial function. Consistent with these observations, we found that αCD3/αCD28 primed Casp1-/- CD8+ T cells displayed enhanced oxidative phosphorylation as compared to WT CD8+ T cells, suggesting that caspase-1 may regulate CD8+ T cell function by reprogramming mitochondrial dynamics and metabolism. Based on these findings, we hypothesize that TCR stimulation of CD8+ T cells triggers caspase-1 activation, which functions to limit T cell activation, mitochondrial bioenergetics, and cell expansion in a tissue-specific manner. In turn, we believe that active caspase-1 is critically required for controlling virus replication within the CNS and minimizing consequential neuronal damage by preventing an over-exuberant T cell response during viral infection. To address this hypothesis, we have two specific aims: 1) How does caspase-1 mediate CD8+ T cell responses during WNV infection? and 2) Aim 2. What are the molecular mechanisms of caspase-1 function in activated CD8+ T cells? The completion of these aims will provide us with a broader understanding of the underlying mechanisms by which caspase-1 regulates CD8+ T cells responses during virus infection.

抽象的 Caspase-1 是炎症小体复合物的重要组成部分，负责裂解亲炎症细胞因子 IL-1β 和 IL-18 并通过切割 Gasdermin D 启动细胞焦亡。西尼罗河病毒（WNV）感染的小鼠模型，我们和其他人之前已经证明了重要性炎症体信号转导促进 IL-1β 介导的保护性免疫。我们现在已经扩展了这些观察并发现了 caspase-1 在调节抗原特异性 CD8+ T 细胞中的新的细胞内在作用西尼罗河病毒感染期间的反应。 CD8+ T 细胞的缺失会导致 WNV 复制不受控制，大脑内明显的神经元损伤。了解大脑内的环境线索如何影响 T 细胞为了了解西尼罗河病毒感染期间的反应，我们对分离的抗原特异性 CD8+ T 细胞进行了转录分析西尼罗河病毒感染后早期和晚期来自脾脏和大脑。通过本次分析，我们发现 caspase-1 以及其他炎症小体信号传导成分在大脑驻留抗原中富集特异性 CD8+ T 细胞与从脾脏分离的抗原特异性 CD8+ T 细胞相比。我们确认与脾脏 CD8+ 相比，活性 caspase-1 在大脑驻留 CD8+ T 细胞中表达更丰富 T细胞。使用共收养转移模型，我们观察到抗原特异性 Casp1-/- CD8+ T 细胞增加与感染期间脾脏和大脑内的 WT CD8+ T 细胞相比。值得注意的是，CD8+ T 细胞没有被感染由 WNV 发现，表明 caspase-1 的激活与病毒感染无关。接下来，我们表征了使用体外 T 细胞受体 (TCR) 刺激测定法在体外发挥 caspase-1 的功能，发现 caspase-1 是 CD3/CD28 刺激后发生自蛋白水解。此外，我们发现 ASC，而不是 NLRP3 或 IL- 1β，在幼稚和刺激的 CD8+ T 细胞中表达。最后，最近的研究将 caspase-1 与线粒体功能。与这些观察结果一致，我们发现 αCD3/αCD28 引发了 Casp1-/- CD8+ 与 WT CD8+ T 细胞相比，T 细胞表现出增强的氧化磷酸化，表明 caspase-1 可能通过重编程线粒体动力学和代谢来调节 CD8+ T 细胞功能。基于根据这些发现，我们假设 TCR 刺激 CD8+ T 细胞会触发 caspase-1 激活，从而以组织特异性方式限制 T 细胞激活、线粒体生物能和细胞扩增。在反过来，我们认为活性 caspase-1 对于控制中枢神经系统内的病毒复制至关重要，并且通过防止病毒感染过程中过度旺盛的 T 细胞反应，最大限度地减少随之而来的神经元损伤感染。为了解决这个假设，我们有两个具体目标：1）caspase-1如何介导CD8+T细胞西尼罗河病毒感染期间的反应？ 2) 目标 2. caspase-1 功能的分子机制是什么激活的 CD8+ T 细胞？这些目标的完成将使我们对 caspase-1 在病毒感染期间调节 CD8+ T 细胞反应的潜在机制。