Ubiquitylation and the Regulation of Immune Homeostasis

描述（由申请人提供）：树突状细胞（DC）是调节免疫稳态以及抗原驱动的免疫应答的先天免疫细胞。树突状细胞的功能受到Toll样受体（TLR）启动的信号的高度调节。因此，调节TLR信号传导途径的细胞内分子对于调节宿主免疫应答是关键的。我们最近发现，A20是一种泛素修饰酶，限制了Toll样受体（TLR）诱导的信号。我们正在研究A20在DC中的表达在调节免疫稳态和应答中的作用。为了实现这一点，我们已经产生了两种基因靶向小鼠品系：一种在所有细胞中破坏A20基因，另一种A20的“floxed”等位基因已经靶向内源性A20基因座。我们将“floxed”小鼠与一种新的CD 11-Cre转基因小鼠品系杂交，该品系在DC中表达具有高选择性和特异性的Cre酶。因此，这些复合A20 flox/flox CD 11 c-Cre小鼠将为我们提供一个非常强大的和新的试剂，用于研究A20在DC中的表达在调节免疫稳态和免疫应答中的作用。我们建议使用这些A20 flox/flox CD 11-cre复合小鼠，以及来自两种小鼠品系的细胞，以确定A20在DC中的表达如何调节其对TLR配体的反应在体外和体内。第一个目标将集中在了解细胞生物学和生物化学A20的调节TLR信号在DC中的作用，并将阐明由A20调节的DC的细胞自主功能。第二个目标将利用A20 flox/flox CD 11 c-Cre小鼠来确定DCs中A20的表达如何调节其体内稳态和活化。这第二个目标也将询问A20在DC中的表达如何调节外周耐受和免疫应答。 公共卫生相关性：该项目的重点是一种名为A20的有效内源性抗炎蛋白，以及它如何在体内调节树突状细胞功能。由于树突状细胞是免疫反应的强大调节剂，并且A20在调节树突状细胞功能中起着关键作用，因此了解A20如何调节树突状细胞和免疫反应可以显着促进炎症性疾病治疗的发展，从而对公共卫生具有重大益处。

DESCRIPTION (provided by applicant): Dendritic cells (DCs) are innate immune cells that regulate both immune homeostasis as well as antigen driven immune responses. The functions of DCs are highly regulated by signals initiated by Toll-like receptors (TLRs). Consequently, intracellular molecules that regulate TLR signaling pathways are pivotal for regulating host immune responses. We have recently found that A20 is a ubiquitin modifying enzyme that restricts toll-like receptor (TLR) induced signals. We are studying the roles of A20 expression in DCs in regulating immune homeostasis and responses. To accomplish this, we have generated two strains of gene targeted mice: one that disrupts the A20 gene in all cells and one in which a "floxed" allele of A20 has been targeted to the endogenous A20 locus. We have interbred the "floxed" mice with a novel strain of CD11-Cre transgenic mouse line that expresses Cre enzyme with high selectivity and specificity in DCs. These compound A20flox/flox CD11c-Cre mice will thus provide us with a very powerful and novel reagent for studying the role of A20 expression in DCs in regulating immune homeostasis and immune responses. We propose to use these A20flox/flox CD11-cre compound mice, as well as cells derived from both strains of mice, to determine how A20 expression in DCs regulates their responses to TLR ligands in vitro and in vivo. The first aim will focus upon understanding the cell biology and biochemistry underlying A20's roles in regulating TLR signaling in DCs, and will elucidate the cell-autonomous functions of DCs that are regulated by A20. The second aim will utilize A20flox/flox CD11c-Cre mice to determine how A20 expression in DCs regulates their homeostasis and activation in vivo. This second aim will also interrogate how A20 expression in DCs regulates peripheral tolerance and immune responses. PUBLIC HEALTH RELEVANCE: This project focuses on a potent endogenous anti-inflammatory protein called A20, and how it regulates dendritic cell functions in vivo. As dendritic cells are powerful regulators of immune responses, and as A20 plays critical roles in regulating dendritic cell functions, understanding how A20 regulates dendritic cells and immune responses could significantly enhance the development of therapies for inflammatory diseases and thus have major benefits for public health.