HIF Regulation of Histoplasma Pathogenesis

项目摘要 二型真菌，荚膜组织胞浆菌（Hc），是美国中西部和东南部的地方病 并且是真菌呼吸道感染的最常见原因。酵母细胞在细胞内环境中茁壮成长 巨噬细胞（M β），直到这些吞噬细胞被细胞因子如干扰素β或粒细胞M β激活 集落刺激因子允许M β促进真菌清除的转录元件是 大部分未知。我们已经发现转录因子缺氧诱导因子（HIF）-1 β和-2 β， 校正感染Hc的M.在最近的一篇文章中，我们报道了M细胞中缺乏HIF-1 β， 通过促进白细胞介素（IL）-10的产生而加重Hc感染。HIF-1 α和HIF-2 β的缺失 而-2 μ g/ml进一步增加了M β产生IL-10的能力。过量的IL-10抑制激活细胞因子的能力 来武装M β的抗Hc功能。我们证明了Hc诱导HIF，而抑制HIF的膨胀 增加增强小鼠和人M β的抗Hc活性。这些数据引发了两个假设：1）HIF 调节IL-10的产生需要MIFs，以及2）MIFs臂MIFs的扩增表达 发挥抗HC活性。为了验证这些假设，我们提出了三个具体目标。目标1将审查 HIF和新陈代谢之间的相互作用。具体来说，我们将确定糖酵解代谢产物是否启动， 肿瘤坏死因子-β维持HIF的表达。我们将确定是否过量生产的特定代谢物 受感染的HIF缺陷细胞促进IL-10的释放。具体目标2将研究HIF如何调节IL-10。我们 将确定miRNA-27 a是否参与IL-10的产生，以及IL-10是否改变HIF-1 α的代谢。 缺陷细胞我们将测试代谢产物调节miRNA表达的可能性， 控制IL-10转录的衰减。我们将确定IL-1受体拮抗剂是否是一个下游效应器， IL-10介导的M β功能抑制。具体目标3将研究HIF的药理学激活如何 我们将确定这些药物的机制和体内作用。我们 期望这些研究能提供对Hc对M β功能调节的更好理解。

Project Summary The dimorphic fungus, Histoplasma capsulatum (Hc), is endemic to the Midwestern and Southeastern US and is the most frequent cause of fungal respiratory infection. Yeast cells thrive in the intracellular environment of macrophages (M) until these phagocytes are activated by cytokines such as interferon- or granulocyte M colony-stimulating factor. The transcriptional elements that license M to promote clearance of the fungus are largely unknown. We have discovered that the transcription factors hypoxia inducing factors (HIF)-1 and -2 calibrate the behavior of M infected with Hc. In a recent publication, we reported that the lack of HIF-1 in M exacerbates infection with Hc by promoting the generation of interleukin (IL)-10. The absence of both HIF-1 and -2 further exaggerates IL-10 production by M. Excessive IL-10 dampens the ability of activating cytokines to arm the anti-Hc function of M. We demonstrate that Hc induces HIFs and that pharmacologically inflating HIF accrual enhances the anti-Hc activity of mouse and human M. These data triggered two hypotheses: 1) HIFs in M are required to temper IL-10 generation, and 2) pharmacologically amplifying expression of HIFs arms M to exert anti-Hc activity. To test these hypotheses, we propose three Specific Aims. Aim 1 will examine the interplay between HIFs and metabolism. Specifically, we will determine if a glycolytic metabolite initiates and tumor necrosis factor- sustains expression of HIFs. We will determine if overproduction of a specific metabolite by infected HIF-deficient cells promotes IL-10 release. Specific Aim 2 will examine how HIFs regulate IL-10. We will determine if miRNA-27a is involved in the generation of IL-10 and if IL-10 modifies the metabolism of HIF- deficient cells. We will test the possibility that a metabolic product regulates the expression of an miRNA that controls the decay of IL-10 transcription. We will ascertain if IL-1receptor antagonist is a downstream effector of IL-10-mediated inhibition of M function. Specific Aim 3 will investigate how pharmacological activation of HIFs promotes the anti-Hc activity of MWe will identify a mechanism and the in vivo effect of these agents. We expect these studies to provide a greater understanding of the regulation of M function in response to Hc.