The Functional Role of the Tetraspanin CD82/Kai1 in Fungal Innate Immunity

四跨膜蛋白 CD82/Kai1 在真菌先天免疫中的功能作用

• 批准号: 10090557
• 负责人: Jatin M Vyas
• 金额: $ 52.94万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-01-11 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10090557
• 关键词: Adhesions; Affect; Antibodies; Aspergillus; Autophagocytosis; Bacteria; Biochemical; Biological Assay; Biological Process; Biotin; C Type Lectin Receptors; CD47 gene; CD81 gene; Candida; Candida albicans; Candidiasis; Carbohydrates; Cell Wall; Cell membrane; Cell physiology; Cells; Cholesterol; Complex; Confocal Microscopy; Critical Illness; DNA Binding; Defect; Dendritic Cells; Enzyme Activation; Event; Family; Generations; Glucans; Hepatitis C virus; Host Defense; Human; Immune; Immune response; Immune system; Immunity; Immunocompromised Host; Infection; Innate Immune Response; Internet; Intracellular Membranes; KAI1 gene; Kinetics; Knockout Mice; Label; Life; Ligands; Lipid Bilayers; Lipids; Listeria monocytogenes; MHC Class II Genes; Malignant Neoplasms; Membrane; Membrane Lipids; Membrane Microdomains; Membrane Proteins; Methods; Microscopy; Modification; Molecular; Molecular Conformation; Morbidity - disease rate; Mus; Mycoses; Myeloid Cells; Names; Natural Immunity; Nematoda; Neoplasm Metastasis; PTPRC gene; PTPRJ gene; Parasites; Pathway interactions; Phagocytes; Phagocytosis; Phagosomes; Phosphorylation; Plasmodium; Play; Protein Family; Proteins; Reaction; Receptor Signaling; Resolution; Role; Second Messenger Systems; Sepsis; Signal Transduction; Sphingolipids; Structure; Surface; System; T-Lymphocyte; TLR2 gene; TLR4 gene; Time; Tissues; Tumor Immunity; Tumor Suppressor Proteins; Ubiquitination; Virus; base; cell motility; cell type; cytokine; dectin 1; exosome; extracellular; fungus; in vivo Model; live cell imaging; macrophage; member; migration; monocyte; mortality; particle; pathogen; pathogenic fungus; receptor; receptor binding; recruit; response; trafficking; tumor; tumor progression

Project Summary: Invasive fungal infections (IFIs) represent a major threat to critically ill and immunocompromised patients and are associated with significant morbidity and mortality. Aspergillus and Candida are opportunistic fungi that cause the majority of these life-threatening infections. In order to exert their deleterious effects, pathogens including viruses, bacteria, parasites, and fungi can hijack tetraspanins for cell invasion or intracellular trafficking. Tetraspanins comprise a family of proteins that are expressed on the plasma membrane, intracellular membranes, and exosomes from nearly all cell types. As their name implies, tetraspanins span the membrane four times and have short intracellular amino and carboxyl-termini and two extracellular loops. Tetraspanins regulate diverse biological processes including cell migration, adhesion, and signaling events by serving as organizers of multimolecular complexes; they form promiscuous associations with one another and other membrane proteins and lipids to generate tetraspanin-enriched microdomains. Elucidating the precise function of tetraspanins has been difficult due to molecular redundancy, a lack of catalytic activity, and insufficient specific antibodies. Despite these challenges, several tetraspanins have been implicated as key regulators of cancer progression and immunity. In particular, CD82 acts as a potent suppressor of tumor metastasis. Tetraspanins including CD82 are also widely expressed in immune cells, but their exact role in undefined. We have made several key observations that begin to define the role of CD82 in fungal immunity. Following phagocytosis by macrophages, CD82 is specifically recruited to phagosomes containing fungal pathogens prior to lysosomal fusion. Remarkably, LysM-Cre CD82 knockout mice infected with Candida albicans have significantly reduced survival compared to wild-type controls, indicating that CD82 plays an important functional role in myeloid cells in response to systemic fungal infection. We developed fungal-like particles to probe directly the immune response to carbohydrates expressed on the fungal cell wall, such as β- 1,3 glucan which is recognized by the pathogen recognition receptor, Dectin-1. We demonstrated that Dectin-1 is critical for phagolysosomal maturation and controls recruitment of the autophagy-related protein, LC3, to fungal containing phagosomes through Syk activation. We also found that CD82 associates with Dectin-1 in macrophages and is important for downstream signaling events in response to fungal infection including Syk activation and ROS generation. To determine the molecular mechanism of CD82 in fungal innate immunity in macrophages, we propose the following two specific aims: (1) Determine the role of CD82 in Dectin-1 signaling by macrophages stimulated with β-1,3 glucan, and (2) Define the role of CD82 in LC3 associated phagocytosis in macrophages challenged by C. albicans.

项目总结： 侵袭性真菌感染(IFI)是危重病人和免疫功能低下患者的主要威胁。 并与严重的发病率和死亡率有关。曲霉和假丝酵母菌是机会真菌 导致这些危及生命的感染中的大多数。为了发挥它们的有害作用，病原体 包括病毒、细菌、寄生虫和真菌在内的生物都可以劫持河豚毒素进行细胞入侵或细胞内入侵。 贩卖人口。Tetraspanins由一系列在质膜上表达的蛋白质组成， 几乎所有细胞类型的胞内膜和外体。顾名思义，河豚毒素跨越了 胞膜有四次，胞内氨基和羧基末端较短，胞外有两个环。 Tetraspanins通过以下方式调节不同的生物学过程，包括细胞迁移、黏附和信号事件 作为多分子复合体的组织者；它们彼此之间形成混杂的缔合 其他膜蛋白和脂类产生富含四氢青霉毒素的微区。阐明精确度 由于分子冗余，缺乏催化活性，四丁糖的功能一直很困难， 特异性抗体不足。尽管有这些挑战，几种四氢青霉毒素已被认为是关键 癌症进展和免疫的调节者。尤其是CD82是一种有效的肿瘤抑制因子。 转移。包括CD82在内的Tetraspanins也在免疫细胞中广泛表达，但它们在 未定义。我们已经做了几个关键的观察，开始定义CD82在真菌免疫中的作用。 巨噬细胞吞噬后，CD82被特异性地募集到含有真菌的吞噬小体中 溶酶体融合前的病原体。值得注意的是，LysM-Cre CD82基因敲除小鼠感染了念珠菌 与野生型对照相比，白念珠菌的存活率显著降低，这表明CD82在 髓系细胞在应对系统性真菌感染中的重要功能。我们开发出了类似真菌的 颗粒直接探测对真菌细胞壁上表达的碳水化合物的免疫反应，如β- 病原体识别受体Dectin-1识别的1，3-葡聚糖。我们证明了这一点 Dectin-1对吞噬小体成熟至关重要，并控制自噬相关蛋白的募集。 对含噬菌体的真菌，通过Syk的激活。我们还发现CD82与 Dectin-1在巨噬细胞中的表达，在真菌感染后的下游信号转导中起重要作用 包括Syk激活和ROS生成。探讨CD82在真菌中的分子作用机制 在巨噬细胞的先天免疫中，我们提出了以下两个具体目标：(1)确定其作用 CD82在β-1，3葡聚糖刺激的巨噬细胞DECIN-1信号转导中的作用 白念珠菌攻击巨噬细胞的LC_3相关吞噬作用。