Candida-endothelial interactions under conditions of flow

流动条件下念珠菌-内皮相互作用

• 批准号: 7091721
• 负责人: MARTIN H THORNHILL
• 金额: $ 16.2万
• 依托单位: UNIVERSITY OF SHEFFIELD
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7091721
• 关键词: Candida; adhesions; conditioning; molecular film; tissues; yeasts

DESCRIPTION (provided by applicant): Problem: Systemic candidiasis is a serious infection with high mortality. Death results from circulating fungal cells entering the tissues and causing extensive organ damage. The first step in this process is adhesion to the endothelial lining of blood vessels followed by transmigration across the endothelial barrier into the tissues. However, we know little about the mechanisms involved in either of these steps and there is conflicting evidence about the role played by yeast and hyphal forms of Candida albicans in both the adhesion and transmigration process. Background: To date, most in vitro studies exploring candidal adhesion to endothelium have been performed under static conditions although it is clear that adhesion processes are very different under the conditions of flow that occur in blood vessels in vivo. Studying the importance of morphogenetic change in these processes has been difficult, because most mutant strains of C. albicans used in these studies are locked into one or other morphological form and have reduced virulence, while morphogenetic conversion of wild type C. albicans is unpredictable and difficult to control. In preliminary studies, we have developed an engineered stain of C. albicans, SSY50-B, in which we can regulate morphogenetic conversion from yeast to hyphal form whilst maintaining the organism's virulence. Separately we have developed assays that allow us to study the adhesion of cells, particularly leukocytes and tumor cells, to endothelial surfaces under conditions of flow similar to those in blood vessels and to follow their subsequent trans-endothelial migration. Our objective is to bring these technologies together so that we can investigate many of the unanswered questions about how C. albicans moves from the circulation into the tissues in systemic candidiasis. More specifically our aims are: Specific aim 1: To develop an in vitro model that will allow us to study and compare the adhesion characteristics of yeast and hyphal forms of Candida albicans to vascular endothelium under conditions of flow. Specific aim 2: To develop an in vitro model to study the trans-endothelial cell migration of C. albicans under conditions of flow, in order to investigate the role of yeast forms, hyphal forms and morphogenetic conversion in the transmigration process. Public benefit: Systemic Candidiasis is a serious life threatening condition in which circulating fungal cells adhere to and migrate across the endothelial lining of blood vessels to enter the tissues where they cause extensive organ damage. By understand the mechanisms involved in Candida-endothelial adhesion and transmigration, we may be able to inhibit Candida migration into the tissues, prevent the resulting tissue damage and increase the exposure of circulating organisms to anti-fungal agents and the reticuloendothelial system so that they can be destroyed.

描述（由申请人提供）： 问题：系统性念珠菌病是一种死亡率很高的严重感染。循环真菌细胞进入组织并造成广泛的器官损伤导致死亡。该过程的第一步是粘附到血管内皮衬里，然后穿过内皮屏障迁移到组织中。然而，我们对这两个步骤中涉及的机制知之甚少，并且关于酵母和白色念珠菌菌丝形式在粘附和迁移过程中所起的作用存在相互矛盾的证据。背景：迄今为止，大多数探索念珠菌与内皮粘附的体外研究都是在静态条件下进行的，尽管很明显粘附过程在体内血管中发生的流动条件下有很大不同。研究形态发生变化在这些过程中的重要性一直很困难，因为这些研究中使用的大多数白色念珠菌突变株被锁定为一种或其他形态形式并降低了毒力，而野生型白色念珠菌的形态发生转变是不可预测的并且难以控制。 在初步研究中，我们开发了一种工程化的白色念珠菌染色剂 SSY50-B，我们可以在其中调节从酵母到菌丝形式的形态发生转化，同时保持生物体的毒力。另外，我们开发了一些检测方法，使我们能够研究细胞（特别是白细胞和肿瘤细胞）在类似于血管的流动条件下对内皮表面的粘附，并跟踪它们随后的跨内皮迁移。我们的目标是将这些技术结合在一起，以便我们能够研究许多悬而未决的问题，即白色念珠菌如何从循环系统转移到系统性念珠菌病的组织中。更具体地说，我们的目标是： 具体目标 1：开发一种体外模型，使我们能够研究和比较流动条件下酵母和白色念珠菌菌丝形式对血管内皮的粘附特性。 具体目标2：建立体外模型来研究白色念珠菌在流动条件下的跨内皮细胞迁移，以研究酵母形态、菌丝形态和形态发生转换在迁移过程中的作用。 公共利益：系统性念珠菌病是一种严重危及生命的疾病，其中循环真菌细胞粘附并迁移穿过血管内皮衬里，进入组织，造成广泛的器官损伤。通过了解念珠菌-内皮粘附和迁移的机制，我们也许能够抑制念珠菌迁移到组织中，防止由此产生的组织损伤，并增加循环生物体与抗真菌药物和网状内皮系统的接触，以便它们能够被摧毁。