细菌生物被膜(BF)一旦形成极难去除，致使感染迁延难愈，是糖尿病足溃疡(DFU)愈合不良的重要因素。金黄色葡萄球菌是DFU感染(DFI)最主要的细菌，我们前期发现：DFI伤口分离的金葡菌比非糖尿病者更易形成BF，进一步研究发现晚期糖基化终末产物(AGEs)在体外可通过增加eDNA促进金葡菌BF形成，其压力应答因子sigB起到关键作用。由此提出假说：AGEs通过调控金葡菌sigB诱导eDNA释放，进而促进BF形成。然而AGEs如何影响金葡菌BF形成及调控sigB的机制尚不明确。本课题拟通过细菌BF模型、糖尿病皮肤感染动物模型、敲除株及回补株构建、RNAi、SEM及CLSM等方法，明确AGEs在金葡菌生物被膜形成中的作用；并通过pulldown结合质谱、EMSA、DNAseI足迹、Co-IP等方法进一步阐明其分子机制，为DFI临床诊断及治疗提供科学依据。

Bacterial biofilms do serious harm to the diabetic foot ulcer (DFU), play a crucial role in infection invasion and spread. Staphylococcus aureus (S. aureus) is the predominant Gram-positive bacterium in diabetic foot infection (DFI). In our previous work, we observed the bacteria isolated from DFU wound were more prone to form biofilm than those bacteria from non-diabetic patients. Furthermore, we found AGEs could promote the S. aureus biofilm formation mainly via increasing eDNA, in which with the sigma B (σB) gene played a critical role, but the mechanisms are still unknown. Consequently, a new hypothesis based on the host-pathogen interaction was proposed: AGEs promote biofilm formation of S. aureus through regulating σB to induce eDNA releasing in diabetic foot infection. To make the study further, by bacterial biofilm model in vitro, diabetic skin infection animal model, gene knock-out mutant and complemented strain, qRT-PCR, immune blotting，SEM and CLSM analysis, we will try to clarify the role of AGEs in S. aureus biofilm formation. And further use pulldown binding mass spectrum identification, EMSA, DNA seI footprint and Co-IP to explore the underlying molecular mechanism. The data generated by this study will provide experimental proof and theoretical support to improve DFI healing.