Interactions of pDCs with Aspergilus

pDC 与曲霉的相互作用

• 批准号: 8605547
• 负责人: Stuart Michael Levitz
• 金额: $ 40.83万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8605547
• 关键词: Acute Disease; Address; Allergic; Animal Model; Antifungal Agents; Apoptosis; Aspergillosis; Aspergillus fumigatus; Autoimmune Diseases; Bacteria; Biology; CD8B1 gene; Cells; Cessation of life; Chelating Agents; Chronic; Data; Dendritic Cells; Diagnostic; Early treatment; Environment; Flow Cytometry; Funding; Fungal Drug Resistance; Gliotoxin; Growth; Host Defense; Human; Hyphae; Immune; Immune response; Immune system; Immunocompromised Host; Immunology; Immunosuppressive Agents; In Vitro; Incubated; Infection; Inflammatory Response; Interferon Type I; Interferons; Intravenous; Knockout Mice; Knowledge; Lead; Leukocyte L1 Antigen Complex; Leukocytes; Life; Link; Lung; Maintenance; Mediating; Microscopy; Modeling; Molds; Morbidity - disease rate; Mus; Mycoses; Mycotoxins; Natural Killer Cells; Necrosis; Neoplasms; Neutropenia; Nucleic Acids; Pathogenesis; Pathology; Patients; Pattern recognition receptor; Persons; Play; Pneumonia; Population; Prevention; Role; T-Lymphocyte; TLR7 gene; TNF gene; Viral; Virus; Zinc; adaptive immunity; arm; base; cell type; chemokine; cytokine; defined contribution; follow-up; fungus; in vivo; in vivo Model; macrophage; monocyte; mortality; neutrophil; novel strategies; pathogen; peripheral blood; prevent; public health relevance; receptor; response

DESCRIPTION (provided by applicant): Aspergillus fumigatus is the most common cause of invasive mold infections. Even with advances in therapy and early diagnostics, mortality rates remain high. Plasmacytoid dendritic cells (pDCs) comprise a functionally distinct lineage of DCs that rapidly produce copious amounts of type I interferons (IFNs) upon stimulation with viruses, predominantly via mechanisms dependent on sensing of viral nucleic acids. pDCs link innate to adaptive immunity by secreting cytokines and by priming T cells. The interplay between pDCs and fungi has not been well characterized. The application builds upon compelling preliminary data demonstrating that: 1) human pDCs directly inhibit fungal growth via a mechanism that involves A. fumigatus-induced pDC death; 2) following stimulation with A. fumigatus hyphae, pDCs release cytokines, including type I IFNs; 3) depletion of pDCs renders mice hypersusceptible to pulmonary and intravenous challenge with A. fumigatus by a mechanism that appears to be due, at least in part, to a dysregulated immune response; and 4) pulmonary infection with A. fumigatus results in pDC influx into the lungs. We hypothesize that pDCs play a major role in host defenses against invasive aspergillosis by mediating direct antifungal activity and by modulating the innate and adaptive immune response. To address this hypothesis, we will define the contribution of pDCs in the defense against A. fumigatus using both in vitro and in vivo models. In Aim 1, we will explore the mechanistic basis of our observations that incubation of pDCs with A. fumigatus in vitro results in fungal recognition, antifungal activity and cytokine release. The receptors required for pDC recognition of the conidial and hyphal fungal morphotypes will be explored. The mechanism of pDC death induced by A. fumigatus will be elucidated. How pDCs mediate antifungal activity will be characterized using both intact pDCs and pDC lysates. Finally, the cytokine and chemokine response of pDCs to A. fumigatus will be investigated. In aim 2, we will follow up our demonstration that pDCs have a non- redundant role in host defenses against aspergillosis by illuminating the mechanisms by which this occurs. The effect of pDC depletion on mortality, fungal burden, immune cell recruitment, pathology and cytokine response will be determined in murine models of invasive aspergillosis. The arms of the immune system required for pDC-mediated protection will be examined by co-depleting pDCs and specific leukocyte subsets and with knockout mice. Lastly, we will determine whether pDCs associate with conidia and hyphae in vivo using flow cytometry and microscopy. Completion of these studies over the funding period will result in major conceptual advances in fungal pathogenesis, fungal immunology and pDC biology. Moreover, the knowledge gained may lead to novel strategies to prevent and treat invasive mycoses.

描述（由申请人提供）：烟曲霉是侵袭性霉菌感染的最常见原因。即使治疗和早期诊断取得进展，死亡率仍然很高。浆细胞样树突状细胞 (pDC) 包含功能独特的 DC 谱系，在受到病毒刺激后，主要通过依赖于病毒核酸感知的机制，快速产生大量 I 型干扰素 (IFN)。 pDC 通过分泌细胞因子和启动 T 细胞将先天免疫与适应性免疫联系起来。 pDC 和真菌之间的相互作用尚未得到很好的表征。该应用建立在令人信服的初步数据之上，证明：1）人类 pDC 通过涉及烟曲霉诱导的 pDC 死亡的机制直接抑制真菌生长； 2)用烟曲霉菌丝刺激后，pDC释放细胞因子，包括I型干扰素； 3) pDC的耗竭使小鼠对烟曲霉的肺部和静脉注射高度敏感，其机制似乎至少部分是由于免疫反应失调所致； 4)烟曲霉肺部感染导致pDC流入肺部。我们假设 pDC 通过介导直接抗真菌活性以及调节先天性和适应性免疫反应，在宿主防御侵袭性曲霉菌病中发挥重要作用。为了解决这个假设，我们将使用体外和体内定义 pDC 在防御烟曲霉中的贡献。 体内模型。在目标 1 中，我们将探索我们观察到的机制基础，即 pDC 与烟曲霉体外孵育会导致真菌识别、抗真菌活性和细胞因子释放。将探索 pDC 识别分生孢子和菌丝真菌形态类型所需的受体。将阐明烟曲霉诱导pDC死亡的机制。将使用完整的 pDC 和 pDC 裂解物来表征 pDC 如何介导抗真菌活性。最后，将研究 pDC 对烟曲霉的细胞因子和趋化因子反应。在目标 2 中，我们将通过阐明发生这种情况的机制来继续证明 pDC 在宿主防御曲霉病中具有非冗余作用。 pDC 消耗对死亡率、真菌负荷、免疫细胞募集、病理学和细胞因子反应的影响将在侵袭性曲霉病小鼠模型中确定。 pDC 介导的保护所需的免疫系统臂将通过共耗竭 pDC 和特定白细胞亚群以及使用基因敲除小鼠进行检查。最后，我们将使用流式细胞术和显微镜确定体内 pDC 是否与分生孢子和菌丝相关。在资助期内完成这些研究将导致真菌发病机制、真菌免疫学和 pDC 生物学方面的重大概念进展。此外，所获得的知识可能会带来预防和治疗侵袭性真菌病的新策略。