MicroRNA Function in the Immune System

描述（由申请人提供）：炎症反应是身体对抗感染的最重要防御之一。炎症的一种引发剂是细菌脂多糖（LPS）。几年前我们发现LPS会诱导巨噬细胞产生3种microRNA。这些小RNA可以对蛋白质水平产生巨大的调节影响。因此，我们一直在从不同的角度对这3种RNA进行表征，这一请求是为了深入研究这些RNA。其中一种microRNA与癌症诱导有关，并可能提供炎症和癌症之间的联系。我们还计划研究另一个microRNA家族，因为它与免疫细胞成熟有潜在的关系。计划中的研究利用了今天操纵小鼠遗传学的能力。因此，过表达和敲除研究将使我们能够检查过多或没有特定microRNA对小鼠生理学的影响。过表达研究将通过将表达microRNA的基因并入病毒载体中，用这些载体感染骨髓干细胞并将感染的细胞转移到致死辐射的宿主小鼠中来进行。我们将使用高分辨率表面标记分析来表征这些microRNA在特定免疫细胞亚群的生成和行为中的作用。在这项工作中，我们还将通过将基因载体递送到细胞中来在细胞中进行体外表达。microRNA是从前体加工而来的，我们发现加工本身是受调节的。我们计划研究如何实现这一规定。为了了解这些microRNA是如何工作的，我们将描述它们调控的靶基因。这涉及生物形成学来寻找候选基因，确定其表达对特定microRNA敏感的基因，然后研究这些基因的作用。对于可能参与免疫细胞发育的microRNA家族，我们怀疑它可能控制着产生抗体的细胞分化的最后阶段。因此，我们将集中研究免疫细胞发育的这一阶段，重点是通常与保护基因组相关的蛋白质p53的可能作用。公共卫生相关性：科学家长期以来一直认为免疫系统是由蛋白质控制的。我们最近的研究表明，一些小RNA分子是炎症和免疫反应的控制者。我们计划研究这些RNA如何发挥作用，重点是癌症和炎症之间的关系。微生物感染和癌症是世界范围内人类疾病的主要原因之一。因此，我们必须继续确定这些破坏性问题的分子基础。最近，micro-RNA已经成为一类新的基因表达调节因子，涉及免疫系统调节和癌症生物学。我们的研究小组已经发现，少数miRNAs是由感染的先天免疫应答诱导的，因此我们建议描述这些miRNAs在宿主防御感染和肿瘤发生中的作用

DESCRIPTION (provided by applicant): The inflammatory response is one of the body's most important defenses against infection. One initiator of inflammation is bacterial lipopolysaccharide (LPS). We found some years ago that LPS will induce in macrophages 3 microRNAs. These are small RNAs that can have huge regulatory influences on protein levels. We have therefore been characterizing these 3 RNAs from various points of view and this request is for funds to study these RNAs in depth. One of the microRNAs has been linked to cancer induction and may provide a link between inflammation and cancer. We have also included plans to study another microRNA family because of its potential relationship to immune cell maturation. The planned studies take advantage of today's ability to manipulate the genetics of mice. Thus, overexpression and knockout studies will allow us to examine the consequences to mouse physiology of too much or none of the particular microRNAs. The overexpression studies will be done by incorporating into viral vectors genes that express the microRNAs, infecting bone marrow stem cells with these vectors and transferring the infected cells to lethally irradiated host mice. We will use high resolution surface marker analysis to characterize the role of these microRNAs in the generation and behavior of particular subsets of immune cells. In this work, we will also use in vitro expression in cells through vectored delivery of genes to the cells. MicroRNAs are processed from precursors and we have found that the processing itself is regulated. We plan to examine how this regulation is achieved. To understand how these microRNAs work we will characterize the target genes that they regulate. This involves bioformatics to find candidates, determining the genes whose expression is sensitive to a particular microRNA and then study of the role of those genes. For the microRNA family that may be involved in immune cell development, we suspect that it could be controlling the final stage of differentiation of the cells that make antibodies. We will therefore concentrate on examining that stage of immune cell development with an emphasis on the possible role of a protein usually associated with protecting the genome, p53. PUBLIC HEALTH RELEVANCE: Scientists have long thought that the immune system is controlled by proteins. Our recent work has implicated some small RNA molecules as controllers of inflammatory and immune responses. We plan to examine how such RNAs might work with an emphasis on the relationship between cancer and inflammation. Microbial infections and cancer are among the leading causes of human diseases worldwide. Therefore, it is imperative that we continue to define the molecular basis underlying these devastating problems. Very recently, micro-RNAs have emerged as a novel class of gene expression regulators that are implicated in both immune system regulation and cancer biology. Our group has found that a small number of miRNAs are potently induced by the innate immune response to infection, and therefore propose to characterize the roles of these miRNAs in host defense against infection and tumorigenesis