An incomplete TCA cycle increases survival of Salmonella Typhimurium during infection of resting and activated murine macrophages.
An incomplete TCA cycle increases survival of Salmonella Typhimurium during infection of resting and activated murine macrophages.
复制标题
DOI：
10.1371/journal.pone.0013871
复制
发表时间：
2010-11-08
期刊：
影响因子：
3.7
通讯作者：
Thompson A
中科院分区：
文献类型：
--
作者：
Bowden SD;Ramachandran VK;Knudsen GM;Hinton JC;Thompson A
与对毒力基因表达、调控和作用的全面分析相比，沙门氏菌在感染过程中的细胞内代谢是一个相对欠研究的领域。我们研究了三羧酸（TCA）循环在鼠伤寒沙门氏菌在静息和活化的巨噬细胞，上皮细胞，以及在小鼠感染过程中的细胞内复制中的作用。我们构建了S.鼠伤寒沙门氏菌，包括gltA、mdh、sdhCDAB、sucAB和sucCD。我们发现，突变体表现出增加的净细胞内复制在休息和激活的小鼠巨噬细胞相比，野生型。相反，上皮细胞感染模型显示S.与野生型相比，鼠伤寒杆菌ΔsucCD和ΔgltA菌株的净细胞内复制减少。乙醛酸分流是不负责的TCA循环突变体在静息巨噬细胞内的复制净增加。我们还证实，在小鼠感染模型中，S。减毒鼠伤寒杆菌ΔsucAB和ΔsucCD菌株的毒力。我们的研究结果表明，TCA循环的中断增加了S。鼠伤寒杆菌在静息和活化的鼠巨噬细胞内存活。相反，上皮细胞是非吞噬细胞，不像巨噬细胞，不能对病原体进行氧化和亚硝化防御反应;我们的结果表明，在HeLa细胞中，S。与野生型相比，鼠伤寒TCA循环突变菌株显示细胞内水平降低或无变化。S.小鼠中的鼠伤寒沙门氏菌ΔsucAB和ΔsucCD突变体，与其在静息和活化巨噬细胞中增加的净细胞内复制相比，表明沙门氏菌可能遇到宿主内的环境，其中完整的TCA循环是有利的。
In comparison to the comprehensive analyses performed on virulence gene expression, regulation and action, the intracellular metabolism of Salmonella during infection is a relatively under-studied area. We investigated the role of the tricarboxylic acid (TCA) cycle in the intracellular replication of Salmonella Typhimurium in resting and activated macrophages, epithelial cells, and during infection of mice. We constructed deletion mutations of 5 TCA cycle genes in S. Typhimurium including gltA, mdh, sdhCDAB, sucAB, and sucCD. We found that the mutants exhibited increased net intracellular replication in resting and activated murine macrophages compared to the wild-type. In contrast, an epithelial cell infection model showed that the S. Typhimurium ΔsucCD and ΔgltA strains had reduced net intracellular replication compared to the wild-type. The glyoxylate shunt was not responsible for the net increased replication of the TCA cycle mutants within resting macrophages. We also confirmed that, in a murine infection model, the S. Typhimurium ΔsucAB and ΔsucCD strains are attenuated for virulence. Our results suggest that disruption of the TCA cycle increases the ability of S. Typhimurium to survive within resting and activated murine macrophages. In contrast, epithelial cells are non-phagocytic cells and unlike macrophages cannot mount an oxidative and nitrosative defence response against pathogens; our results show that in HeLa cells the S. Typhimurium TCA cycle mutant strains show reduced or no change in intracellular levels compared to the wild-type. The attenuation of the S. Typhimurium ΔsucAB and ΔsucCD mutants in mice, compared to their increased net intracellular replication in resting and activated macrophages suggest that Salmonella may encounter environments within the host where a complete TCA cycle is advantageous.