Kidney Cu Homeostasis and Ceruloplasmin during Infection and Inflammation

项目摘要 铜是一种基本的微量营养素，也可能对生物系统有害。因此哺乳动物细胞需要 严格控制铜的动态平衡。肾脏似乎在调节铜方面特别有效，因为这个器官 显示在铜过剩或铜限制条件下铜波动的最小幅度。 然而，库洛塔实验室最近发表的研究表明，肾脏中的铜水平在 感染和炎症。特别是在播散性念珠菌病的小鼠模型中，感染了 真菌病原体白色念珠菌刺激肾脏铜含量下降，入侵病原体通过 激活真菌铜饥饿应激反应。在肾脏铜水平下降的同时，血清铜水平上升。 在我的初步研究中，我发现这种高血清铜的原因是血清中的强烈升高 铜蓝蛋白(Cp)是一种急性期蛋白。铜蓝蛋白是一种控制铁的多铜氧化酶 动态平衡和我观察到CP蛋白水平和CP活性的增加可以解释几乎所有 血清铜升高。我推测，在白色念珠菌感染期间，对高铜的需求 产生铜蓝蛋白会触发肾脏中铜的损失，而铜的下降是通过 肾脏铜摄取或排出的调节。为了研究这一假设，我将实现以下目标。 目的1：将宿主和真菌的铜反应定义为感染严重程度的函数。我将确定 刺激宿主铜反应所需的感染(升高血清CP和降低肾脏铜)以及 真菌对铜的反应(激活铜饥饿胁迫反应)。目标2：了解 肾脏铜在感染过程中丢失。我将研究肾脏铜含量下降的机制： 这包括铜摄取减少还是铜外流增加？我将仔细研究蛋白质水平和定位 铜吸收转运蛋白CTR1和铜外排转运蛋白ATP7A试图回答这个问题。目标 3：测定肾脏铜丢失的信号。确定血清CP是否足以诱发肾脏 在没有真菌感染的情况下失去铜，我会给小鼠注射脂多糖和热灭活的白念珠菌细胞， 两者都会诱导炎症反应，包括无感染的CP诱导。此外，我还会 检测感染白色念珠菌的Cp-/-纯合子缺失小鼠是否出现肾脏铜丢失现象。 总之，这些研究将深入了解肾脏铜稳态受以下因素影响的机制 感染和炎症。

Project Summary Cu is an essential micronutrient that can also be toxic to biological systems. Mammalian cells therefore need to tightly control Cu homeostasis. The kidney appears particularly effective at regulating Cu because this organ displays some of the smallest magnitude of Cu fluctuations during conditions of Cu excess or Cu limitation. However, recently published work in the Culotta lab has shown that kidney Cu levels can fluctuate during infection and inflammation. Specifically in a murine model of disseminated candidiasis, infection with the fungal pathogen Candida albicans stimulated a drop in kidney Cu and the invading pathogen responded by activating a fungal Cu starvation stress response. Concurrent to this drop in kidney Cu, serum Cu levels rose. In my preliminary studies, I discovered that the cause of this high serum Cu is a strong elevation in serum ceruloplasmin (Cp), an acute phase protein. Ceruloplasmin is a multi-copper oxidase for controlling Fe homeostasis and I observed increases in both Cp protein levels and Cp activity that can account for virtually all the elevated serum Cu. I hypothesize that during C. albicans infection, the demand for high Cu in producing ceruloplasmin triggers a loss in Cu from the kidney, and this drop in Cu is mediated through regulation of kidney Cu uptake or efflux. To investigate this hypothesis I will carry out the following aims. Aim 1: To define the host and fungal Cu responses as a function of infection severity. I will identify the level of infection required to stimulate the host Cu response (elevating serum Cp and decreasing kidney Cu) as well as the fungal Cu response (activate the Cu starvation stress response). Aim 2: To understand the mechanism for kidney Cu loss during infection. I will investigate the mechanism by which kidney Cu decrease occurs: does this involve reduced Cu uptake or enhanced Cu efflux? I will scrutinize both protein levels and localization of the Cu uptake transporter CTR1 and the Cu efflux transporter ATP7A in an effort to answer this question. Aim 3: Determine the signal for Cu loss in the kidney. To determine whether serum Cp is sufficient to induce kidney loss of Cu without fungal infection, I will inject mice with lipopolysaccharide and heat-killed C. ablicans cells, both of which will induce an inflammatory response including Cp induction without infection. Furthermore I will test if the phenomenon of kidney Cu loss occurs in Cp-/- homozygous deletion mice infected with C. albicans. Together these studies will provide insight into the mechanisms by which kidney Cu homeostasis is affected by infection and inflammation.