Molecular basis of giant Extracellular Matrix Binding Protein (Embp) mediated Staphylococcus epidermidis adherence to fibronectin and biofilm accumulation on artificial surfaces

本项目的总体目标是全面了解Embp介导的S.表皮生物膜形成及其与实验性异物相关感染发病过程中细菌/宿主相互作用的相关性。这一目标将通过解决Embp依赖S的关键方面来实现。本研究采用多种实验方法，包括分子生物学技术、细胞培养系统和建立植入物相关感染的三维模型系统，对表皮葡萄球菌的毒力进行了研究。1.我们将在分子/生物化学水平上描述Embp / FN相互作用的确切模式，并分析它们在S.表皮与表面组织化FN结合。此外，还将分析FN纤维形成过程中动态构象变化的重要性和连续暴露的隐蔽表位，例如FN III 12至14。表皮与FN的结合对于引发植入物相关感染至关重要。Embp被证明是FN依赖的S.表皮粘附到植入物表面。然而，这种相互作用的确切分子决定因素目前尚不清楚。我们小组的工作表明，Embp采用了迄今未知的与FN相互作用的模式，涉及结合到隐蔽模块FN III 12至14。2.将建立并验证植入物相关感染的三维模型。该模型将允许在Embp依赖S的时间和空间动态分析。表皮植入物定殖、生物膜形成和与宿主先天免疫细胞的相互作用。依据：目前用于S.表皮生物膜的形成并不反映在外来物质和由细胞外基质组成的周围组织之间的界面处发生的体内感染的复杂情况，以及多种驻留细胞（例如成纤维细胞、巨噬细胞）。这种特殊的地形，基本上适用于大多数S。表皮装置相关感染（例如，与人工关节、CSF分流器、人工心脏瓣膜相关）可能对生物膜发育和S.总的来说，这些目标的分析将不仅提供对细菌发病机理和微生物/宿主相互作用的一般方面的新见解，而且更具体地解决与S.表皮植入物感染。考虑到临床问题的严重性，拟议的项目可以为开发新的治疗和/或预防方法提供新的起点，这些方法是对抗毁灭性器械相关S。表皮感染

The overall objective of this project is to obtain comprehensive insights into the molecular basis of Embp mediated S. epidermidis biofilm formation and its relevance to bacterial / host interactions during pathogenesis of experimental foreign material associated infections. The objective will be reached by addressing key aspects of Embp dependent S. epidermidis virulence using a variety of experimental approaches, including molecular biological techniques, cell culture systems and establishment of three dimensional model systems of implant associated infections. 1. We will characterize the exact modalities of Embp / FN interactions on a molecular / biochemical level and analyze their role during S. epidermidis binding to surface organized FN. In addition, the importance of dynamic conformational changes during FN fibrillogenesis and consecutive exposure of cryptic epitopes, e.g. FN III12 to 14, will be analyzed.Rational: S. epidermidis binding to FN is of paramount importance for initiation of implant associated infections. Embp proved to be necessary for FN dependent S. epidermidis adherence to implant surfaces. However, the exact molecular determinants of this interaction are currently unclear. Work from our groups demonstrates that Embp employs a so far unknown mode of interaction with FN involving binding to cryptic modules FN III12 to 14. 2. A three dimensional model of implant associated infections will be established and validated. The model will allow for analysis of the temporal and spatial dynamics during Embp dependent S. epidermidis implant colonization, biofilm formation and interactions with host innate immune cells. Rational: Currently assay systems used for analysis of S. epidermidis biofilm formation do not reflect the complex setting of an in vivo infection occurring at the interface between foreign materials and the surrounding tissues consisting of extracellular matrix, and a diverse set of resident cells (e.g. fibroblasts, macrophages). This specific topography, which essentially applies for most S. epidermidis device related infections (e.g. associated with prosthetic joints, CSF shunts, artificial heart valves) could have dramatic impact on biofilm development and dynamic interactions of S. epidermidis with host cells.Collectively, analysis of these objectives will not only provide novel insights into general aspects of bacterial pathogenesis and microbe / host interactions, but more specifically address central aspects related to the pathogenesis of S. epidermidis implant infections. Considering the gravity of the clinical problem, the proposed project could provide new starting points for development of novel therapeutic and / or prophylactic approaches that are necessary to combat devastating device related S. epidermidis infections.