Regulation of iNOS gene expression in human T cells

一氧化氮（NO）是一种生物活性气体，参与人体生理的许多方面。一氧化氮在细胞中由三种相关的酶合成：神经元型一氧化氮合酶、诱导型一氧化氮合酶（iNOS）和内皮型一氧化氮合酶。虽然所有这些酶在不同的生物学环境下对一氧化氮的生成都很重要，但我最近发现了人类T细胞中iNOS表达在增强人类免疫反应中的作用，并表明趋化因子基质细胞衍生因子-1 α (SDF-1a)是人类T细胞中iNOS的蛋白质诱导剂。然而，在T细胞中调节iNOS表达的细胞内机制尚不清楚。此外，一般来说，人类细胞中iNOS表达的调控是不完全确定的，与通常用于研究哺乳动物生物学的动物（即小鼠和大鼠）有很大不同。因此，我的提议的目标是了解sdf -1a诱导的iNOS在人T细胞中的表达调控，以及它在人T细胞生物学中的作用。第一部分将研究调节sdf -1a诱导的人T细胞iNOS表达的细胞内信号通路。这将涉及siRNA分子抑制信号酶ERK1/2和PI3K的表达，然后在缺乏ERK1/2和PI3K表达的人T细胞中检测sdf -1a诱导的iNOS表达。Ras在介导潜在的反馈调节回路中的作用也将被检查。提案的第二部分将确定在人类T细胞中控制iNOS基因表达的DNA元件和相关转录因子。最后，提案的第三部分将研究sdf -1a诱导的iNOS在人类T细胞存活和迁移中的作用。我最近发现NO可以抑制人类T细胞的细胞死亡，我将研究iNOS在响应SDF-1a时产生的NO是否以类似的方式起作用。所描述的工作将引起细胞生物学家和免疫学家的兴趣，因为它将提供关于人类细胞中iNOS表达调控的新信息，并深入了解与人类免疫相关的T细胞生物学。

Nitric oxide (NO) is a bioactive gas involved in many aspects of human physiology. It is synthesized in cells by three related enzymes: neuronal nitric oxide synthase, inducible nitric oxide synthase (iNOS), and endothelial NOS. While all of these enzymes are important in the generation of NO under different biological circumstances, I have recently identified a role for iNOS expression in human T cells in the augmentation of human immune responses and shown that the chemokine stromal cell derived factor-1alpha (SDF-1a) is a protein inducer of iNOS in human T cells. However, the intracellular mechanisms regulating iNOS expression in T cells are unknown. Also, the regulation of iNOS expression in human cells, in general, is incompletely defined and is very different than that in animals commonly used to study mammalian biology, namely mice and rats. Therefore, the goal of my proposal is to understand the regulation of SDF-1a-induced iNOS expression in human T cells, and the role this plays in human T cell biology. The first part will study the intracellular signaling pathways that regulate SDF-1a-induced iNOS expression in human T cells. This will involve the inhibition of expression of the signaling enzymes ERK1/2 and PI3K by siRNA molecules, and then examination of SDF-1a-induced iNOS expression in human T cells lacking expression of ERK1/2 and PI3K. The role of Ras in mediating a potential feedback regulatory loop will also be examined. The second part of the proposal will determine the DNA elements and related transcription factors controlling the expression of the iNOS gene in human T cells. Finally, the third part of the proposal will examine the role of SDF-1a-induced iNOS in human T cell survival and migration. I have recently found that NO can inhibit cell death of human T cells and I will examine whether NO produced from iNOS in response to SDF-1a acts in a similar manner. The described work will be of interest to cell biologists and immunologists as it will provide new information on the regulation of iNOS expression in human cells, and insight into T cell biology as it relates to human immunity.