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.

摘要 亚临床（无症状）疟疾与恶性疟原虫（Pf）是常见的儿童谁住在中度- 撒哈拉以南非洲的高传播地区。虽然亚临床疟疾可能是亚微观的，但受影响的 学龄儿童（8 - 15岁）的血涂片通常呈阳性，每毫升中含有数百万个寄生虫 鲜血虽然亚临床疟疾通常归因于获得性适应性免疫， 生物量，寄生虫血症（血涂片+）超过热原阈值的任何合理估计。如何 是否有可能保持没有发烧和明显的疟疾症状与专利寄生虫血症？相比 有症状的疟疾，暂时持续的（慢性）亚临床疟疾似乎是由一种复杂的 促炎和抗炎细胞因子和免疫细胞的平衡。科学的前提是 建议是先天免疫细胞，包括血液单核细胞（Mo）的表观遗传修饰， 亚临床疟疾的炎症途径。此外，我们假设免疫系统 涉及抗炎性Pf-induced 1型T调节细胞（Tr1）和IL-10以及 增强的IL-1RA产生抑制先天免疫炎症途径。亚临床疟疾发病率高， 流行病学意义，因为寄生虫血症在作为主要储存者的学童中持续数月， 的配子体所需的维持Pf传输到本地按蚊载体。事实上，据估计， 60%的新蚊子感染可归因于这一人口。为了验证我们的假设，我们将招募 肯尼亚学龄儿童（8 - 15岁）在一项纵向队列研究中比较和分析免疫差异， A）慢性亚临床疟疾（基线时Pf+涂片）和保持无发热的患者之间的参数 尽管反复涂片+x 16周）相对于B）发展为发热性临床疟疾长达2周的儿童 在无发热的Pf+涂片之后。这些队列中慢性Pf暴露的免疫参数的特异性将 通过与居住在附近高地地区的年龄和性别匹配的儿童进行比较进行审讯， 疟疾流行率为零。将通过RNA-seq分析来自儿童的PBMC和分离的Mo，以确定 激活基因表达途径。我们将定义免疫细胞亚群的差异，转录 活化的因子及其效应细胞因子表达谱。在 此外，我们将使用染色质免疫沉淀（ChIP）DNA测序，以确定是否表观基因组的 对患有慢性亚临床疟疾的儿童进行修饰以使促炎基因沉默或相反， 来激活抗炎的细胞。最后，我们将通过转座酶活性测定进行鉴定和比较 染色质高通量测序（ATAC-seq）在关键基因表达途径中开放染色质位点 在Mo中，将这些区域与来自同一儿童的RNA-seq数据进行比对。的 这一项目的成功完成将使我们对这一机制有新的重要认识。 亚临床疟疾以及如何改变这种疾病状态以促进消灭疟疾。