New Mechanistic Insights into Purine Biosynthesis with Second Messenger c-di-AMP in Relation to Biofilm-Related Persistent Methicillin-Resistant Staphylococcus aureus Infections.
New Mechanistic Insights into Purine Biosynthesis with Second Messenger c-di-AMP in Relation to Biofilm-Related Persistent Methicillin-Resistant Staphylococcus aureus Infections.
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DOI：
10.1128/mbio.02081-21
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发表时间：
2021-12-21
期刊：
影响因子：
6.4
通讯作者：
Xiong YQ
中科院分区：
文献类型：
--
作者：
Li L;Li Y;Zhu F;Cheung AL;Wang G;Bai G;Proctor RA;Yeaman MR;Bayer AS;Xiong YQ
持续性耐甲氧西林金黄色葡萄球菌（MRSA）血管内感染是一种具有重大临床挑战性的侵袭性、危及生命的金黄色葡萄球菌。金黄色葡萄球菌感染我们最近证明嘌呤生物合成在这种持续性感染中起重要作用。环二腺苷酸（c-di-AMP）是一种重要的和普遍存在的第二信使，调节细菌中的许多细胞途径。然而，嘌呤生物合成途径和c-di-AMP之间是否存在影响持久结果的调节联系尚不清楚。在这里，我们证明了嘌呤生物合成突变型MRSA菌株，ΔpurF菌株，（与其同基因亲本株相比），在体外表现出以下显著差异：（i）较低的ADP、ATP和c-di-AMP水平;（ii）随着细胞外DNA（eDNA）水平的降低和Triton X-100诱导的自溶，生物膜形成较少，同时生物膜形成相关的两种蛋白的表达增强，组分调节系统lytSR及其下游基因lrgB;（iii）增加万古霉素（货车）结合和VAN诱导的裂解;和（iv）降低壁磷壁酸（WTA）水平和WTA生物合成相关基因tarH的表达。证实了这些数据，dacA（编码c-di-AMP合成所需的二腺苷酸环化酶）突变株（dacAG 206 S株与其同基因野生型MRSA和dacA补充株）显示出显著降低的c-di-AMP水平，与上文对于purF突变体所见的体外作用相似，并且在实验性生物膜相关MRSA血管内感染模型中对货车处理过敏。这些结果揭示了嘌呤生物合成和c-di-AMP之间的重要交叉点，这有助于MRSA血管内感染中生物膜相关的持久性。该信号通路代表了针对持续性MRSA感染的逻辑治疗靶点。
Persistent methicillin-resistant Staphylococcus aureus (MRSA) endovascular infections represent a significant clinically challenging subset of invasive, life-threatening S. aureus infections. We have recently demonstrated that purine biosynthesis plays an important role in such persistent infections. Cyclic di-AMP (c-di-AMP) is an essential and ubiquitous second messenger that regulates many cellular pathways in bacteria. However, whether there is a regulatory connection between the purine biosynthesis pathway and c-di-AMP impacting persistent outcomes was not known. Here, we demonstrated that the purine biosynthesis mutant MRSA strain, the ΔpurF strain (compared to its isogenic parental strain), exhibited the following significant differences in vitro: (i) lower ADP, ATP, and c-di-AMP levels; (ii) less biofilm formation with decreased extracellular DNA (eDNA) levels and Triton X-100-induced autolysis paralleling enhanced expressions of the biofilm formation-related two-component regulatory system lytSR and its downstream gene lrgB; (iii) increased vancomycin (VAN)-binding and VAN-induced lysis; and (iv) decreased wall teichoic acid (WTA) levels and expression of the WTA biosynthesis-related gene, tarH. Substantiating these data, the dacA (encoding diadenylate cyclase enzyme required for c-di-AMP synthesis) mutant strain (dacAG206S strain versus its isogenic wild-type MRSA and dacA-complemented strains) showed significantly decreased c-di-AMP levels, similar in vitro effects as seen above for the purF mutant and hypersusceptible to VAN treatment in an experimental biofilm-related MRSA endovascular infection model. These results reveal an important intersection between purine biosynthesis and c-di-AMP that contributes to biofilm-associated persistence in MRSA endovascular infections. This signaling pathway represents a logical therapeutic target against persistent MRSA infections.