Innate Immune Activation in Malaria

摘要：疟疾急性感染常伴有全身性细胞因子风暴症状。 这些症状是由吞噬细胞激活引起的全身炎症反应引起的。整体而言 我们正在进行的项目的目标是确定先天免疫激活和调节的机制 治疗疟疾的临床症状和并发症。这笔赠款是R01 AI079293的续期。这个RO1有 卓有成效，出版了40份出版物，其中包括16份同行评议的原创手稿 最近一个资助期的工作(其中9份直接与赠款有关，另外5份论文得到支助 通过巴西与赠款相关的基础设施)。在过去的十年里，我们已经定义了我们认为的 主要的“疟疾毒素”及其同源受体：寄生虫富含AT的DNA、免疫复合体、血球蛋白、游离 血红素，和GPI主播。我们发现这些配体驱动Toll样受体(TLR2，3，4，9)，NOD样受体 受体(NLRP3，NLRP12)，黑色素瘤缺失2(AIM2)，以及cGAS-STING途径。我们的工作导致了 认识到胞质DNA结合蛋白CnBP调节IL12b和IFNG，在某些条件下， I型干扰素。我们已经描述了疟疾的先天免疫记忆现象，这是一部分 一种表观遗传过程，既可以保护人类宿主，也可以在某些条件下导致严重的 疟疾(尤其是如果伴有细菌感染)。最近，我们发现了几个LncRNA 疟疾刺激的吞噬细胞，其中许多可能调节临床疾病。因此，我们已经完成了 我们5年前开始做的大部分事情。在这次更新中，我们计划重点确定最基本的 结合细胞培养研究，在体外调节疟疾先天免疫系统的方法 用鼠标对病人样本进行分析。有三个目标。这项拨款的主要假设是 先天性免疫反应是通过染色质的表观遗传修饰以及在 转录水平。这种调节涉及淋巴细胞和吞噬细胞的相互作用，导致先天的 免疫训练和各种表观遗传学变化。表观遗传变化涉及到对 染色质，染色质可及性的改变(目标1)。此外，疟疾期间的炎症信号 在包括LUCAT-1和LIMIT在内的长非编码RNA的生成中，我们将详细探讨它们的作用 在体外，在LUCAT-1 KO小鼠和人类临床样本中(目标2)。最后，我们将定义 转录调节因子，称为CnBP，是一种核酸结合蛋白，我们最初认为它是DNA 传感器。CnBP已被证明通过其相互作用参与调节IL12β的转录和表达 C-Rel和IL12启动子(目标3)。在上面简要描述的所有目标中，我们将分析白细胞 来自我们位于巴西波尔图韦尔霍港的发烧疟疾患者(间日疟原虫和恶性疟原虫)。这笔赠款 是一个雄心勃勃的项目，建立在成功完成两项先前雄心勃勃的赠款的基础上。在接下来的时间 在资金周期内，我们希望对我们关于疟疾先天免疫的知识作出更大贡献。

ABSTRACT: Acute infection with malaria is often accompanied by the symptoms of a systemic cytokine storm. These symptoms result from a systemic inflammatory response via the activation of phagocytes. The overall goal of our ongoing project is to define the mechanisms of innate immune activation and regulation that account for the clinical symptoms and complications of malaria. This grant is a renewal of R01 AI079293. This RO1 has been highly productive having resulted in 40 publications including 16 peer-reviewed manuscripts of original work in the latest funding period (9 of these directly related to the grant, an additional 5 papers were supported by grant-related infrastructure in Brazil). Over the last decade, we have defined what we believe to be the principal “malaria toxins” and their cognate receptors: parasite AT-rich DNA, immune complexes, hemozoin, free heme, and GPI anchors. We found that these ligands drive Toll-like receptors (TLRs 2, 3, 4, 9), NOD-like receptors (NLRP3, NLRP12), absent in melanoma 2 (AIM2), and the cGAS-STING pathway. Our work led to recognition that a cytosolic DNA binding protein Cnbp, regulates IL12b and IFNg and, under certain conditions, type I interferons. We have described the phenomena of innate immune memory in malaria, which is one part of an epigenetic process that may both protect the human host or, under certain conditions, might result in severe malaria (especially if accompanied by bacterial infection). More recently, we have identified several lncRNAs in malaria-stimulated phagocytes, many of which might regulate clinical disease. Thus, we have accomplished most of what we set out to do 5 years ago. In this renewal, we plan to focus on identifying the most basic methods by which the innate immune system is regulated in malaria by combining cell culture studies, in vitro mouse work with the analysis of patient samples. There are three Aims. The major hypothesis of the grant is that the innate immune response is highly regulated via epigenetic modifications of chromatin as well as at the transcriptional level. This regulation involves the interaction of lymphoid cells with phagocytes, resulting in innate immune training and a variety of epigenetic changes. The epigenetic changes involve the modification of chromatin, alterations of chromatin accessibility (Aim 1). In addition, inflammatory signals during malaria result in the generation of long non-coding RNAs including LUCAT-1 and LIMIT, whose roles we will explore in detail in vitro, in a LUCAT-1 KO mouse and in human clinical samples (Aim 2). Finally, we will define the role of a transcriptional regulator known as Cnbp, a nucleic acid binding protein that we initially thought to be a DNA sensor. Cnbp has proven to be involved in regulating IL12beta transcription and expression via its interaction with c-Rel and the IL12 promoter (Aim 3). In all of the Aims described briefly above, we will analyze leukocytes from febrile patients with malaria (both P. vivax and P falciparum) from our site in Porto Velho, Brazil. This grant is an ambitious project built upon the successful completion of two previously ambitious grants. Over the next funding cycle, we hope to contribute significantly more to our knowledge of innate immunity in malaria.