Life Science Research Center, Nine Biopharm Co., LTD. Cheongju 28161, Republic of Korea.
Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Republic of Korea.
J Microbiol Biotechnol. 2023 Apr 28;33(4):430-440. doi: 10.4014/jmb.2208.08034. Epub 2023 Jan 27.
The type three secretion system (T3SS) is a major virulence system of (). The effector protein Exotoxin S (ExoS) produced by is secreted into the host cells via the T3SS. For the purpose of an experiment on inhibitors with regard to ExoS secretion, we developed a sandwich-type enzyme-linked immunosorbent assay (ELISA) system. Quercetin was selected because it has a prominent ExoS inhibition effect and also is known to have anti-inflammatory and antioxidant effects on mammalian cells. In this study, we investigated the effects of quercetin on the expression and secretion of ExoS using ELISA and Western blot analysis methods. The results showed that the secretion of ExoS was significantly decreased by 10 and 20 μM of quercetin. Also, , , , and which are composed of the T3SS needle, are reduced by quercetin at the mRNA level. We also confirmed the inhibitory effect of quercetin on cytokines (IL-6, IL-1β, and IL-18) in -infected H292 cells by real-time polymerase chain reaction (PCR) and ELISA. Collectively, quercetin inhibits the secretion of ExoS by reducing both ExoS production and the expression of the needle protein of T3SS. Furthermore, these results suggest that quercetin has the potential to be used as an anti-toxic treatment for the inflammatory disease caused by infection.
III 型分泌系统 (T3SS) 是 () 的主要毒力系统。 产生的效应蛋白 Exotoxin S (ExoS) 通过 T3SS 被分泌到宿主细胞中。为了研究针对 ExoS 分泌的抑制剂实验，我们开发了一种夹心型酶联免疫吸附测定 (ELISA) 系统。槲皮素被选中是因为它具有显著的 ExoS 抑制作用，并且已知对哺乳动物细胞具有抗炎和抗氧化作用。在这项研究中，我们使用 ELISA 和 Western blot 分析方法研究了槲皮素对 ExoS 表达和分泌的影响。结果表明，10 和 20 μM 的槲皮素显著减少了 ExoS 的分泌。此外，T3SS 针由 、 、 和 组成，其在 mRNA 水平也因槲皮素而减少。我们还通过实时聚合酶链反应 (PCR) 和 ELISA 证实了槲皮素对 感染的 H292 细胞中细胞因子 (IL-6、IL-1β 和 IL-18) 的抑制作用。综上所述，槲皮素通过减少 ExoS 的产生和 T3SS 针蛋白的表达来抑制 ExoS 的分泌。此外，这些结果表明，槲皮素有可能被用作治疗 感染引起的炎症性疾病的解毒治疗方法。
