南方医科大学学报

南方医科大学学报 ›› 2026, Vol. 46 ›› Issue (10): 2548-2557.doi: 10.12122/j.issn.1673-4254.2026.10.22

• • 上一篇    

醉茄素A通过下调 ibeR 表达抑制新生儿脑膜炎大肠杆菌的生物膜形成和黏附能力

余政颖1(), 周炳亮1, 孟祥顺1, 王蕾2, 黄胜和3(), 曹虹1()   

  1. 1.南方医科大学，公共卫生学院微生物学系//广东省热带病研究重点实验室，广东 广州 510515
    2.珠江医院检验医学部微生物组医学中心，广东 广州 510655
    3.美国加利福尼亚州洛杉矶南加州大学
  • 收稿日期:2026-03-05 出版日期:2026-10-20 发布日期:2026-10-26
  • 通讯作者: 黄胜和,曹虹 E-mail:19568703090@163.com;shhuang35@gmail.com;gzhcao@smu.edu.cn
  • 作者简介:余政颖，硕士，E-mail: 19568703090@163.com
  • 基金资助:
    南方医科大学公共卫生学院资助(GW202431)

Withaferin A inhibits biofilm formation and adhesion of neonatal meningitis Escherichia coli by downregulating ibeR expression

Zhengying YU1(), Bingliang ZHOU1, Xiangshun MENG1, Lei WANG2, Shenghe HUANG3(), Hong CAO1()   

  1. 1.Department of Microbiology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health, Southern Medical University, Guangzhou 510515, China, Los Angeles, CA, United States
    2.Microbiome Medicine Center, Department of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510655, China, Los Angeles, CA, United States
    3.University of Southern California, Los Angeles, CA, United States
  • Received:2026-03-05 Online:2026-10-20 Published:2026-10-26
  • Contact: Shenghe HUANG, Hong CAO E-mail:19568703090@163.com;shhuang35@gmail.com;gzhcao@smu.edu.cn

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摘要：

目的 探讨醉茄素A（WA）对新生儿致脑膜炎大肠杆菌（NMEC）生物膜形成机制及黏附能力的干预效果。以及ibeR作为调节因子对NMEC生物膜形成机制和血脑屏障（BBB）的黏附作用的影响。 方法 用CCK-8法测定不同浓度WA处理后细胞的存活率。通过预实验、细胞毒性评估，筛选出合适的WA浓度用于正式实验。培养新生儿致脑膜炎大肠杆菌RS218（E44），用不同浓度WA干预设置分组，对照组、WA（1 μmol/L）、WA（2 μmol/L）、WA（5 μmol/L），测量吸光度（A600 nm）检测细菌生长能力，用结晶紫染色和生物膜形成指数（SBF）计算比较生物膜的形成能力。qPCR法检测添加WA后E44中ibeR、ibeA、ibeT、TnaA表达水平。培养已成功构建的ibeR缺失突变株（BR2），探究ibeR对生长能力、生物膜形成能力的影响。在体外培养人脑微血管内皮细胞（HBMECs），然后与E44及BR2进行共培养。针对不同的菌种，设立对照组以及WA（1 μmol/L）组、WA（2 μmol/L）组，以研究不同浓度WA和ibeR对菌株粘附率的影响。培养E44及BR2，不同浓度WA干预设置分组，测定上清液吲哚含量，为进一步探究吲哚在ibeR调控的生物膜形成中的作用，检测添加不同浓度吲哚下E44和BR2的生物膜含量。 结果 计算IC50的结果结合WA对细胞毒性的影响，选择WA干预浓度为2 μmol/L。WA不影响细菌增殖，但抑制生物膜形成能力，添加不同浓度的WA后，E44菌株形成的生物膜随着WA浓度增加减少（P<0.0001），BR2菌株无明显变化。qPCR结果显示，WA组的ibeR表达水平显著性下降（P<0.0001）。ibeR缺失不影响细菌增殖，相同时间点，BR2的生物膜形成能力均显著低于E44（P<0.0001）。ibeR缺失显著削弱菌黏附能力（P<0.0001），与对照组相比，WA组中E44粘附率显著性下降（P<0.0001），且随浓度增加，抑制效果越强（P<0.0001），BR2粘附率无明显变化。与对照组相比，添加不同浓度WA的E44组的吲哚产量显著增高（P<0.0001），生物膜含量显著降低（P<0.0001），BR2组无明显变化。 结论 ibeR缺失使NMEC粘附能力下降和抑制生物膜形成，ibeR通过调控吲哚的生成调节生物膜形成。WA可影响ibeR的表达，WA不影响细菌增殖仅抑制生物膜形成能力，WA通过影响ibeR抑制生物膜形成，对细菌粘附能力的有剂量依赖性影响。

关键词: 新生儿致脑膜炎大肠杆菌, 醉茄素A, ibeR, 生物膜, 血脑屏障

Abstract:

Objective To investigate the effect of Withaferin A (WA) on biofilm formation and adhesion of neonatal meningitis Escherichia coli (NMEC) and the regulatory role of ibeR. Methods CCK-8 assay was used to determine the sub-inhibitory concentration of WA in cultured human brain microvascular endothelial cells (HBMECs). The NMEC strain RS218 (E44) and an ibeR deletion mutant (BR2) were treated with 1, 2, and 5 μmol/L WA, and the changes in biofilm formation were evaluated by crystal violet staining and SBF assay; the expression levels of ibeR, ibeA, and ibeT were detected by qPCR. HBMECs co-cultured with E44 or BR2 were examined for bacterial adhesion, and indole production in the supernatants and the effect of exogenous indole on biofilm formation were evaluated. Results Based on cytotoxicity test, 2 μmol/L WA was used for subsequent experiments. WA dose-dependently reduced biofilm formation in E44 but not in the BR2 strain but did not significantly inhibit proliferation of either strain. WA treatment significantly downregulated ibeR expression in the bacteria. Deletion of ibeR did not affect bacterial growth but significantly decreased biofilm formation and adhesion to HBMECs. WA treatment also reduced cell adhesion ability of E44, which was not observed in BR2. WA significantly increased indole production and decreased biofilm content in E44 but not in BR2. Conclusion IbeR regulates NMEC biofilm formation and adhesion likely by modulating indole production. WA dose-dependently inhibits biofilm and adhesion of NMEC by downregulating ibeR without affecting bacterial growth.

Key words: neonatal meningitis escherichia coli, withaferin a, iber, biofilm, blood-brain barrier