PI3K signalling in regulatory T cells.

我们的免疫系统保护我们免受病毒、细菌和寄生虫等病原体的感染。与任何防御机制一样，附带损害的风险是不可避免的。免疫系统使用几种不同的策略来限制对宿主的损害。T细胞（一种白细胞）在协调免疫反应、杀死受感染细胞和维持免疫记忆（疫苗的基础）方面发挥着核心作用。产生的每个T细胞表面都有一个独特的受体，可以与病原体的成分结合，从而识别它们的存在。每个T细胞表达一种独特的、随机产生的特异性。当然，这种受体总是有识别身体不同器官的潜力。为了避免对身体器官的明显攻击，具有强烈自我反应性的T细胞在发育过程中被消除。然而，一些自身反应性T细胞逃避了这种消除过程，需要加以控制。最近，T细胞的一个亚群被称为调节性T细胞（Tregs）。这些T细胞是自我反应的，但它们不是启动免疫反应，而是抑制潜在的破坏性T细胞的功能。缺乏这种T细胞群的个体会死于对身体不同器官的毁灭性攻击。人们对更多地了解treg如何工作非常感兴趣。特别是，科学家们想知道他们是否可以利用Tregs的力量来预防自身免疫性疾病，如关节炎、糖尿病和多发性硬化症。此外，制药公司正在开发针对引起自身免疫性疾病的正常T细胞的药物，希望避免抑制treg的功能。PI - 3激酶是一种将信息从细胞外传递到细胞核的酶，允许细胞根据环境线索做出决定。当T细胞识别病原体的成分时，PI 3-激酶途径被激活并影响随之而来的免疫反应类型。通过抑制PI 3激酶，可以避免某些有害的免疫反应。因此，制药公司目前正在开发和测试针对p110delta的药物，p110delta是一种在T细胞中表达的PI 3激酶（但不是在主要器官的细胞中表达）。我们发现，在T细胞中PI 3-激酶活性被基因阻断的小鼠中，Tregs无法阻断传统T细胞的功能。这可能是开发抗p110delta药物的一个严重劣势，需要进一步研究。为此，我们打算鉴定Tregs中可能受PI 3-激酶活性缺乏影响的基因。这将帮助我们更好地准确理解p110 δ抑制如何影响Treg，但也可能帮助我们识别Treg功能所需的其他基因；其中大多数目前尚不清楚。我们还将研究p110delta在免疫应答过程中如何促进调节性T细胞的发育。迄今为止，大多数实验都是用细胞培养进行的，并不一定能完全反映Tregs在自身免疫攻击中的作用。为了进一步研究这方面的问题，我们将研究p110delta缺陷treg预防自身免疫性糖尿病的能力。这需要一个更复杂的细胞相互作用网络，在这种情况下，绘制p110 δ缺陷T细胞的精确缺陷将是重要的。最后，我们将在treg中特异性地删除p110delta基因。该实验将明确揭示Tregs中的p110delta是否对控制免疫系统的其余部分至关重要。这项研究的好处是，我们将对控制treg救命特性的基因和分子有更深入的了解。此外，这项研究将帮助制药公司了解以p110delta为靶点的药物的优势和潜在危险。

Our immune system protects us from infection by pathogens such as viruses, bacteria and parasites. As with any defence mechanism, the risk of collateral damage is unavoidable. The immune system uses several different strategies to limit the damage to the host. T cells (a type of white blood cell) play a central role in orchestrating immune responses, in the killing of infected cells and in the maintenance of immunological memory (the basis for vaccines). Each T cell that develops has a unique receptor on the surface that can bind to components of pathogens and hence recognise their presence. Each T cell expresses a unique, randomly generated specificity for such recognition. There is of course always a potential for such receptors to recognise different organs in the body. To avoid overt attacks on the body's organs, T cells with strong self-reactivity are eliminated during development. However, some self-reactive T cells escape this elimination process and need to be kept in check. Recently, a subgroup of T cells / called regulatory T cells (Tregs) / has been identified. These T cells are self-reactive, but instead of initiating immune responses, they suppress the function of potentially destructive T cells. Individuals who lack this population of T cells die young from a devastating attack on different organs in the body. There is great interest in learning more about how the Tregs work. In particular, scientists want to know if they can harness the power of Tregs to protect against autoimmune diseases such as arthritis, diabetes and multiple sclerosis. In addition, pharmaceutical companies developing drugs against normal T cells that cause autoimmune diseases, want to avoid inhibiting the function of Tregs. PI 3-kinases are enzymes that relay information from outside the cell to the cell nucleus, allowing the cell to make decisions based on environmental cues. When a T cell recognises a component of a pathogen, the PI 3-kinase pathway is activated and influences the type of immune response that ensues. By inhibiting PI 3-kinases, certain harmful immune responses may be averted. Pharmaceutical companies are therefore currently developing and testing dugs against p110delta, the type of PI 3-kinase expressed in T cells (but not by cells in the major organs). We have found, using mice in which PI 3-kinase activity in T cells has been blocked genetically, that Tregs are unable to block the function of conventional T cells. This could be a serious disadvantage for the development of drugs against p110delta and needs to be investigated further. To this end, we intend to identify genes that may be affected by the lack of PI 3-kinase activity in Tregs. This will help us better understand precisely how p110delta inhibition may affect Tregs, but may also help us identify other genes that are required for Treg function; most of these are currently unknown. We will also examine how p110delta contributes to the development of regulatory T cells during an immune response. Most of the experiments to date were performed with cell cultures and do not necessarily fully reflect the role of Tregs during an autoimmune attack. To examine this aspect further, the capacity of p110delta-deficient Tregs to protect against autoimmune diabetes will be examined. This requires a more complex network of cellular interactions and it will be important to map the precise defects of p110delta-deficient T cells in this context. Finally, we will delete the gene for p110delta specifically in Tregs. This experiment will reveal definitively whether p110delta in Tregs is essential for keeping the rest of the immune system in check. The benefit of this research is that we will gain a greater understanding of the genes and molecules that control the life-saving properties of Tregs. In addition, this research will help inform pharmaceutical companies about the advantages, as well as potential dangers, associated with drugs that target p110delta.