Health Sciences Research Centre, University of Roehampton, London, United Kingdom.
Division of Cancer, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom.
mSphere. 2018 Aug 8;3(4):e00374-18. doi: 10.1128/mSphere.00374-18.
is a facultative intracellular pathogen that invades and replicates within many types of phagocytic and nonphagocytic cells. During intracellular infection, is capable of subverting xenophagy and escaping to the cytosol of the host cell. Furthermore, drug-induced autophagy facilitates the intracellular replication of , but the reasons behind this are unclear. Here, we have studied the host central carbon metabolism during intracellular infection. We found extensive metabolic rerouting and detected several distinct metabolic changes that suggested starvation-induced autophagic flux in infected cells. These changes included increased uptake but lower intracellular levels of glucose and low abundance of several essential amino acids, as well as markedly upregulated glutaminolysis. Furthermore, we show that AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinase (ERK) phosphorylation levels are significantly increased in infected cells. Interestingly, while autophagy was activated in response to invasion, most of the autophagosomes detected in infected cells did not contain bacteria, suggesting that induces the autophagic flux during cell invasion for energy generation and nutrient scavenging. Accordingly, AMPK inhibition halted intracellular proliferation. escapes from immune recognition by invading a wide range of human cells. Once the pathogen becomes intracellular, the most important last resort antibiotics are not effective. Therefore, novel anti-infective therapies against intracellular are urgently needed. Here, we have studied the physiological changes induced in the host cells by during its intracellular proliferation. This is important, because the pathogen exploits the host cell's metabolism for its own proliferation. We find that severely depletes glucose and amino acid pools, which leads to increased breakdown of glutamine by the host cell in an attempt to meet its own metabolic needs. All of these metabolic changes activate autophagy in the host cell for nutrient scavenging and energy generation. The metabolic activation of autophagy could be used by the pathogen to sustain its own intracellular survival, making it an attractive target for novel anti-infectives.
是一种兼性细胞内病原体,能够侵入并在多种吞噬细胞和非吞噬细胞内复制。在细胞内感染期间,能够颠覆异噬作用并逃到宿主细胞的细胞质中。此外,药物诱导的自噬有助于 的细胞内复制,但背后的原因尚不清楚。在这里,我们研究了宿主中央碳代谢在 细胞内感染期间的变化。我们发现了广泛的代谢重排,并检测到了几种不同的代谢变化,这些变化表明感染细胞中存在饥饿诱导的自噬流。这些变化包括葡萄糖摄取增加但细胞内水平降低,以及几种必需氨基酸含量低,同时谷氨酰胺分解代谢明显上调。此外,我们还表明感染细胞中 AMP 激活的蛋白激酶 (AMPK) 和细胞外信号调节激酶 (ERK) 的磷酸化水平显著升高。有趣的是,虽然自噬在 入侵时被激活,但在感染细胞中检测到的大多数自噬体并不包含细菌,这表明 在细胞入侵时诱导自噬流以产生能量和营养物质的摄取。因此,AMPK 抑制阻止了 的细胞内增殖。通过入侵广泛的人类细胞来逃避免疫识别。一旦病原体成为细胞内的,最有效的最后手段抗生素就无效了。因此,迫切需要针对细胞内 的新型抗感染疗法。在这里,我们研究了宿主细胞在 细胞内增殖过程中诱导的生理变化。这很重要,因为病原体利用宿主细胞的代谢来进行自身的增殖。我们发现 严重消耗葡萄糖和氨基酸池,这导致宿主细胞分解谷氨酰胺增加,以试图满足自身的代谢需求。所有这些代谢变化都激活了宿主细胞的自噬作用,以获取营养物质并产生能量。自噬的代谢激活可以被病原体用来维持自身的细胞内生存,使其成为新型抗感染药物的一个有吸引力的靶点。