Post-Graduation Program in Cellular and Molecular Biology, Federal University of Rio Grande do Sul., Porto Alegre, Rio Grande do Sul 91501-970, Brazil.
Faculty of Veterinary, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91540-000, Brazil.
J Proteome Res. 2024 Nov 1;23(11):4896-4906. doi: 10.1021/acs.jproteome.4c00286. Epub 2024 Oct 3.
The aim of this study was to identify, using proteomics, the molecular alterations caused by human serum exposure to ACH2. The analysis was performed under two different conditions, native serum from healthy donors and heat-inactivated serum (to inactivate the complement system), and at two different times, after 1 and 4 h of serum exposure. More than 1,000 bacterial proteins were identified at each time point. Enterobactin, a siderophore involved in iron uptake, and proteins involved in translation were upregulated at 1 h, while the chaperone ProQ and the glyoxylate cycle were identified after 4 h. Enzymes involved in the stress response were downregulated, and the SOD activity was validated using an enzymatic assay. In addition, an intricate metabolic adaptation was observed, with pyruvate and thiamine possibly involved in survival and virulence in the first hour of serum exposure. The addition of exogenous thiamine contributes to bacterial growth in human serum, corroborating this result. During 4 h of serum exposure, the glyoxylate cycle (GC) probably plays a central role, and the addition of exogenous succinate suppresses the GC, inducing a decrease in serum resistance. Therefore, serum exposure causes important changes in iron acquisition, the expression of virulence factors, and metabolic reprogramming, which could contribute to bacterial serum resistance.
本研究旨在通过蛋白质组学鉴定人血清暴露于 ACH2 后引起的分子变化。该分析在两种不同条件下进行，即来自健康供体的天然血清和热失活血清（以灭活补体系统），并在血清暴露 1 和 4 小时后进行。在每个时间点都鉴定出了超过 1000 种细菌蛋白。铁摄取相关的铁载体 Enterobactin 和参与翻译的蛋白质在 1 小时时上调，而伴侣蛋白 ProQ 和乙醛酸循环在 4 小时时被鉴定出来。参与应激反应的酶被下调，并且使用酶测定法验证了 SOD 活性。此外，还观察到一种复杂的代谢适应，在血清暴露的最初 1 小时内，丙酮酸和硫胺素可能参与了细菌的生存和毒力。添加外源性硫胺素有助于细菌在人血清中的生长，这与该结果相符。在 4 小时的血清暴露期间，乙醛酸循环（GC）可能发挥核心作用，并且添加外源性琥珀酸盐会抑制 GC，导致血清抗性降低。因此，血清暴露会导致铁摄取、毒力因子表达和代谢重编程的重要变化，这可能有助于细菌的血清抗性。
