Defective pgsA contributes to increased membrane fluidity and cell wall thickening in S. aureus with high-level daptomycin resistance.
Defective pgsA contributes to increased membrane fluidity and cell wall thickening in S. aureus with high-level daptomycin resistance.
复制标题
pgsA 缺陷会导致具有高水平达托霉素耐药性的金黄色葡萄球菌膜流动性增加和细胞壁增厚。
DOI：
10.1101/2023.04.11.536441
复制
发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Hines,KellyM
中科院分区：
文献类型：
--
作者：
Freeman,ChristianD;Hansen,Tayte;Urbauer,Ramona;Wilkinson,BrianJ;Singh,VineetK;Hines,KellyM
达托霉素是一种膜靶向最后手段的抗菌治疗剂，用于治疗甲氧西林和/或万古霉素耐药金黄色葡萄球菌引起的感染。在达托霉素治疗失败的罕见事件中，耐药性的来源通常可直接归因于金黄色葡萄球菌膜磷脂生物合成途径内或控制细胞包膜反应和膜稳态的调节系统内的突变。在这里，我们描述了金黄色葡萄球菌菌株 N315 的达托霉素抗性分离株中细胞包膜的结构变化，该菌株在最常报道的与达托霉素抗性相关的基因中获得了突变：mprF、yycG 和 pgsA。除了作为达托霉素抗性标志的磷脂酰甘油（PG）水平降低之外，具有高水平达托霉素抗性的突变体其膜脂中的支链脂肪酸（BCFA）增加，膜流动性增加，细胞壁厚度增加。然而，同位素标记的直链脂肪酸 (SCFA) 在脂质合成中的成功利用表明，异常的 BCFA:SCFA 比例是由脂肪酸合成的上游变化引起的，而不是 PgsA 的结构偏好。 RT-qPCR 研究表明，达托霉素抗性分离株中丙酮酸脱氢酶 (pdhB) 的表达受到抑制，已知该酶会增加 BCFA 水平。虽然与额外的 pdhB 副本互补没有效果，但 pgsA 突变的互补导致 PG 形成增加、细胞壁厚度减少、正常 BCFA 水平恢复以及达托霉素敏感性增加。总的来说，这些结果表明，除了磷脂酰甘油水平之外，pgsA还通过影响膜流动性和细胞壁厚度来促进达托霉素耐药性。
Daptomycin is a membrane-targeting last-resort antimicrobial therapeutic for the treatment of infections caused by methicillin- and/or vancomycin-resistant Staphylococcus aureus. In the rare event of failed daptomycin therapy, the source of resistance is often attributable to mutations directly within the membrane phospholipid biosynthetic pathway of S. aureus or in the regulatory systems that control cell envelope response and membrane homeostasis. Here we describe the structural changes to the cell envelope in a daptomycin-resistant isolate of S. aureus strain N315 that has acquired mutations in the genes most commonly reported associated with daptomycin-resistance: mprF, yycG, and pgsA. In addition to the decreased phosphatidylglycerol (PG) levels that are the hallmark of daptomycin-resistance, the mutant with high-level daptomycin resistance had increased branched-chain fatty acids (BCFAs) in its membrane lipids, increased membrane fluidity, and increased cell wall thickness. However, the successful utilization of isotope-labeled straight-chain fatty acids (SCFAs) in lipid synthesis suggested that the aberrant BCFA:SCFA ratio arose from upstream alteration in fatty acid synthesis rather than a structural preference in PgsA. RT-qPCR studies revealed that expression of pyruvate dehydrogenase (pdhB) was suppressed in the daptomycin-resistant isolate, which is known to increase BCFA levels. While complementation with an additional copy of pdhB had no effect, complementation of the pgsA mutation resulted in increased PG formation, reduction in cell wall thickness, restoration of normal BCFA levels, and increased daptomycin susceptibility. Collectively, these results demonstrate that pgsA contributes to daptomycin resistance through its influence on membrane fluidity and cell wall thickness, in addition to phosphatidylglycerol levels.
登录
查看更多内容
影响因子：
5.2
作者：
Bayer AS;Schneider T;Sahl HG
通讯作者：
Sahl HG
影响因子：
158.5
作者：
Fowler, Vance G., Jr.;Boucher, Helen W.;Cosgrove, Sara E.
通讯作者：
Cosgrove, Sara E.
用于测量金黄色葡萄球菌膜流动性的荧光偏振 (FP) 测定。
影响因子：
--
作者：
K. Tiwari;S. Sen;C. Gatto;B. Wilkinson
通讯作者：
B. Wilkinson
DOI：
10.1073/pnas.1812066116
发表时间：
2019-02-26
影响因子：
11.1
作者：
Jiang, Jhih-Hang;Bhuiyan, Md Saruar;Peleg, Anton Y.
通讯作者：
Peleg, Anton Y.
膜脂酰基链组成对达托霉素孔形成影响的机理研究
影响因子：
3.4
作者：
Beriashvili, David;Taylor, Robert;Palmer, Michael
通讯作者：
Palmer, Michael