Innate Immune Mechanisms Governing Subclinical Malaria in Children

控制儿童亚临床疟疾的先天免疫机制

• 批准号: 10460703
• 负责人: Douglas T Golenbock
• 金额: $ 73.77万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10460703
• 关键词: 15 year old; ATAC-seq; Address; Affect; Africa; Africa South of the Sahara; Age; Agonist; Anopheles Genus; Anti-Inflammatory Agents; Area; Binding Sites; Biological Assay; Biomass; Blood; Blood specimen; Cells; Child; Chromatin; Chronic; Clinical; Communities; Complex; County; Culicidae; Cytokine Gene; Cytometry; DNA; DNA sequencing; Data; Development; Disease; Elements; Enhancers; Enrollment; Epidemiology; Epigenetic Process; Equilibrium; Fever; Gene Expression; Gene Expression Profile; Genes; Goals; High-Throughput Nucleotide Sequencing; Homeostasis; Immune; Immunomodulators; In Vitro; Individual; Infection; Inflammation Mediators; Inflammatory; Inflammatory Response; Innate Immune Response; Interferon Type II; Interferons; Interleukin-1 Receptors; Interleukin-10; Interleukin-6; Kenya; Knowledge; Legal patent; Longitudinal cohort study; Malaria; Measurement; Modification; Parasitemia; Parasites; Pathway interactions; Peripheral Blood Mononuclear Cell; Plasma; Plasmodium falciparum; Population; Production; Proteins; Public Health; RNA analysis; Regulator Genes; Regulatory Pathway; Regulatory T-Lymphocyte; Research; Role; School-Age Population; Site; Source; Specificity; Symptoms; T-Lymphocyte Subsets; TNF gene; Testing; Tissue-Specific Gene Expression; Toll-like receptors; Transposase; Work; adaptive immunity; age group; antagonist; chromatin immunoprecipitation; cohort; comparison group; cytokine; effector T cell; epigenetic marker; epigenome; innate immune mechanisms; innate immune pathways; insight; monocyte; promoter; response; rural area; sex; transcription factor; transcriptome sequencing; transmission process; vector; vector mosquito

ABSTRACT Subclinical (asymptomatic) malaria with Plasmodium falciparum (Pf) is common in children who live in moderate- to-high transmission areas of sub-Saharan Africa. Although subclinical malaria may be submicroscopic, affected school-age children (ages 8-15 years) often have positive blood smears that include millions of parasites per mL of blood. While subclinical malaria is typically attributed to acquired adaptive immunity that tightly controls the Pf biomass, patent parasitemia (blood smear+) exceeds any reasonable estimate of the pyrogenic threshold. How is it possible to remain without fever and overt malaria symptoms with patent parasitemia? In contrast to symptomatic malaria, temporally persistent (chronic) subclinical malaria seems to be maintained by a complex balance of pro-inflammatory and anti-inflammatory cytokines and immune cells. The scientific premise of this proposal is that epigenetic modifications of innate immune cells, including blood monocytes (Mo), modulate inflammatory pathways underlying subclinical malaria. Furthermore, we hypothesize that an immune homeostasis network involving anti-inflammatory Pf-induced type 1 T regulatory cells (Tr1) and IL-10 as well as enhanced IL-1RA production suppress innate immune inflammatory pathways. Subclinical malaria is of high epidemiologic significance as parasitemia persists for months in schoolchildren who serve as the major reservoir of gametocytes required to sustain Pf transmission to local anopheline vectors. Indeed, it is estimated that ~ 60% of new mosquito infections can be attributed to this demographic. To test our hypotheses, we will enroll Kenyan schoolchildren (ages 8-15) in a longitudinal cohort study to compare and analyze differences in immune parameters between those with A) chronic subclinical malaria (Pf+ smear at baseline and who remain afebrile despite repeatedly smear+ x 16 weeks) relative to B) children who develop febrile clinical malaria up to 2 weeks after an afebrile Pf+ smear. The specificity of immune parameters for chronic Pf exposure in these cohorts will be interrogated by comparison to age and sex matched children residing in a nearby highlands area where malaria endemicity is ~ zero. PBMC and isolated Mo from children will be analyzed by RNA-seq to determine activated gene expression pathways. We will define the differences in immune cell subsets, the transcription factors that are activated and their effector cytokine expression profiles using mass cytometry (CyTOF). In addition, we will use chromatin immunoprecipitation (ChIP) DNA sequencing to determine if the epigenomes of children with chronic subclinical malaria are modified in order to silence proinflammatory genes or conversely, to activate anti-inflammatory ones. Finally, we will identify and compare by Assay for Transposase-Accessible Chromatin with high-throughput Sequencing (ATAC-seq) open chromatin sites in key gene expression pathways in Mo from the comparator groups and align these regions with RNA-seq data from the same child. The successful completion of this project should give us new and important insights as to the mechanism of subclinical malaria and how this disease state can be modified to facilitate malaria eradication.

抽象的 恶性疟原虫（PF）的亚临床（无症状）疟疾常见于生活在中等的儿童中 撒哈拉以南非洲的最高传播区域。尽管亚临床疟疾可能是微观的，但受到影响 学龄儿童（8-15岁）经常有阳性污渍，包括每毫升数百万寄生虫 血液。尽管亚临床疟疾通常归因于获得的自适应免疫，该免疫力紧紧控制了PF 生物量，专利寄生虫（血液涂片+）超过了热原阈值的任何合理估计。如何 是否可以保持发烧和明显的疟疾症状，并具有专利寄生虫的症状？与 有症状的疟疾，暂时持久（慢性）亚临床疟疾似乎是由复合物维持的 促炎和抗炎细胞因子和免疫细胞的平衡。科学前提 建议是对先天免疫细胞的表观遗传修饰，包括血单核细胞（MO），调节 亚临床疟疾的炎症途径。此外，我们假设是免疫 涉及抗炎PF诱导的1 T型调节细胞（TR1）和IL-10的稳态网络以及 增强的IL-1RA产生抑制了先天免疫炎症途径。亚临床疟疾很高 作为寄生虫的流行病学意义在学童中持续了几个月，他们是主要水库 将PF传播到局部瞬间向量所需的配子细胞。确实，据估计〜 60％的新蚊子感染可以归因于这种人群。为了检验我们的假设，我们将注册 肯尼亚学童（8-15岁）在一项纵向队列研究中，以比较和分析免疫的差异 a）慢性亚临床疟疾（基线时的PF+涂片并保持在Afebrile）之间的参数 尽管反复涂片+ x 16周）相对于b）患有发热临床疟疾的儿童长达2周 经过afebrile PF+涂片。在这些队列中，免疫参数对慢性PF暴露的特异性将 与居住在附近的高地地区的年龄和性匹配的孩子相比，可以通过询问 疟疾流行〜零。 RNA-Seq将分析来自儿童的PBMC和分离的MO 活化的基因表达途径。我们将定义免疫细胞子集的差异，转录 使用质量细胞术（CytoF）激活的因素及其效应子细胞因子表达谱。在 此外，我们将使用染色质免疫沉淀（CHIP）DNA测序来确定是否表观构想 为了使促炎基因沉默或相反，患有慢性亚临床疟疾的儿童被修饰 激活抗炎作用。最后，我们将通过测定转座酶访问来识别和比较 具有高通量测序（ATAC-SEQ）的染色质（ATAC-SEQ）在关键基因表达途径中开放染色质位点 在MO中，比较组组中，并将这些区域与来自同一孩子的RNA-Seq数据对齐。这 该项目的成功完成应该为我们提供有关机制的新重要见解 亚临床疟疾以及如何修饰这种疾病状态以促进疟疾消除。