staphylococcus aureus biofilms mediate keratinocyte apoptosis

描述(由申请人提供)：项目摘要/摘要慢性伤口在美国影响大约650万患者，相当于每年250亿美元的医疗费用。由于医疗费用不断攀升、人口老龄化以及糖尿病和肥胖症发病率上升，这一负担正在迅速增加。研究表明，生物膜有助于创面的慢性化，金黄色葡萄球菌是慢性创面生物膜中的一种普遍存在的物种；然而，生物膜如何导致延迟的再上皮化仍不清楚。最近发现，浮游金黄色葡萄球菌和金黄色葡萄球菌生物膜对角质形成细胞(KC)具有不同的致死作用。因此，假设浮游金黄色葡萄球菌产生导致KC坏死的可溶性因子；而金黄色葡萄球菌生物膜产生介导KC特定凋亡途径的可溶性因子。这一假设将通过全面研究暴露在生物膜条件培养液或浮游条件培养液中的KC细胞的凋亡特征来验证，包括磷脂酰丝氨酸转位和DNA片段化。接下来，还将分析KC培养中内在和/或外在的凋亡途径的诱导。KC细胞凋亡的更具体的分子分析将使用大型定量聚合酶链式反应阵列进行研究。最后，金黄色葡萄球菌生物被膜产生的细菌产物将通过核磁共振和质谱分析进行鉴定，并对鉴定的产物进行筛选，以确定它们是否为诱导凋亡的因素。这项研究的目标包括确定金黄色葡萄球菌生物被膜介导的分子途径和诱导KC凋亡的特定细菌产物。明确定义的信号通路和诱导凋亡的细菌产物可能为未来的慢性创面治疗和诊断提供分子理性，这可能会对患者的健康产生重大影响。 公共卫生相关性：项目简介这项调查的目标是确定金黄色葡萄球菌生物膜如何杀死一种皮肤细胞：角质形成细胞。这项研究将有助于开发用于治疗慢性伤口的抗生物膜疗法。越来越多的人正在或将受到与慢性伤口相关的发病率和死亡率的困扰，即使一小部分慢性伤口病例是由微生物生物膜感染引起的，抗生物膜疗法的发展也将是一项重大的社会贡献。

DESCRIPTION (provided by applicant): PROJECT SUMMARY/ABSTRACT Chronic wounds affect approximately 6.5 million patients in the United States and represent $25 billion in annual health care costs. This burden is rapidly increasing due to escalating health care costs, an aging population, and the rising incidence of diabetes and obesity. Studies demonstrate that biofilms contribute to wound chronicity, and that Staphylococcus aureus is a prevalent species found in chronic wound biofilms; however, how biofilms contribute to the delayed re-epithelialization remains unclear. It was recently demonstrated that planktonic S. aureus and S. aureus biofilms have differential lethal effects on keratinocytes (KC). Therefore, it is hypothesized that planktonic S. aureus produce soluble factors that induce KC necrosis; whereas S. aureus biofilms produce soluble factors that mediate specific apoptotic pathways in KC. This hypothesis will be tested by comprehensively investigating KC cultures exposed to either biofilm-conditioned medium or planktonic-conditioned medium for apoptotic characteristics, including phosphatidylserine translocation and DNA fragmentation. Next, KC cultures will also be analyzed for the induction of the intrinsic and/or extrinsic apoptotic pathways. More specific molecular analysis of KC apoptosis will be investigated using a large format quantitative polymerase chain reaction array. Finally, bacterial products produced by S. aureus biofilms will be identified using nuclear magnetic resonance and mass spectrometry analysis, and the identified products will be screened to determine if they are apoptosis-inducing factors. The goals of this investigation include identifying the molecular pathways mediated by S. aureus biofilms and the specific bacterial products that induce KC apoptosis. Indentifying clearly defined signaling pathways and apoptosis- inducing bacterial products may provide a molecular rational for future chronic wound therapies and diagnostics, which may have a significant impact on patient health. PUBLIC HEALTH RELEVANCE: PROJECT NARRATIVE The goal of this investigation is to identify how Staphylococcus aureus biofilms kill one type of skin cell: the keratinocyte. This investigation will aid in the development of anti-biofilm therapies for the treatment of chronic wounds. A growing portion of the population is or will be afflicted with the morbidity and mortalit associated with chronic wounds, and even if a fraction of chronic wound cases stem from a microbial biofilm infection, the development of an anti-biofilm therapy would be a significant social contribution.