Tannic acid inhibits Escherichia coli biofilm formation and underlying molecular mechanisms: Biofilm regulator CsgD

Jinying Long; Can Yang; JingJing Liu; Chengjun Ma; Min Jiao; Huiming Hu; Jing Xiong; Yang Zhang; Wei Wei; Hongzao Yang; Yuzhang He; Maixun Zhu; Yuandi Yu; Lizhi Fu; Hongwei Chen

doi:10.1016/j.biopha.2024.116716

Tannic acid inhibits Escherichia coli biofilm formation and underlying molecular mechanisms: Biofilm regulator CsgD

Biomed Pharmacother. 2024 May 11:175:116716. doi: 10.1016/j.biopha.2024.116716. Online ahead of print.

Authors

Jinying Long¹, Can Yang¹, JingJing Liu², Chengjun Ma², Min Jiao², Huiming Hu³, Jing Xiong⁴, Yang Zhang⁴, Wei Wei⁵, Hongzao Yang⁵, Yuzhang He⁶, Maixun Zhu⁴, Yuandi Yu⁴, Lizhi Fu⁷, Hongwei Chen⁸

Affiliations

¹ College of Veterinary Medicine, Southwest University, Chongqing 402460, China; National Center of Technology Innovation for Pigs, Chongqing 402460, China; Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China.
² College of Veterinary Medicine, Southwest University, Chongqing 402460, China; National Center of Technology Innovation for Pigs, Chongqing 402460, China.
³ College of Veterinary Medicine, Southwest University, Chongqing 402460, China.
⁴ National Center of Technology Innovation for Pigs, Chongqing 402460, China; Chongqing Academy of Animal Sciences, Chongqing 402460, China.
⁵ College of Veterinary Medicine, Southwest University, Chongqing 402460, China; National Center of Technology Innovation for Pigs, Chongqing 402460, China; Traditional Chinese Veterinary Research Institute, Southwest University, Chongqing 402460, China.
⁶ College of Veterinary Medicine, Southwest University, Chongqing 402460, China; Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China.
⁷ National Center of Technology Innovation for Pigs, Chongqing 402460, China; Chongqing Academy of Animal Sciences, Chongqing 402460, China. Electronic address: fulz@cqaa.cn.
⁸ College of Veterinary Medicine, Southwest University, Chongqing 402460, China; National Center of Technology Innovation for Pigs, Chongqing 402460, China; Immunology Research Center, Medical Research Institute, Southwest University, Chongqing 402460, China; Traditional Chinese Veterinary Research Institute, Southwest University, Chongqing 402460, China. Electronic address: dyxchw@swu.edu.cn.

PMID: 38735084
DOI: 10.1016/j.biopha.2024.116716

Abstract

Biofilms often engender persistent infections, heightened antibiotic resistance, and the recurrence of infections. Therefor, infections related to bacterial biofilms are often chronic and pose challenges in terms of treatment. The main transcription regulatory factor, CsgD, activates csgABC-encoded curli to participate in the composition of extracellular matrix, which is an important skeleton for biofilm development in enterobacteriaceae. In our previous study, a wide range of natural bioactive compounds that exhibit strong affinity to CsgD were screened and identified via molecular docking. Tannic acid (TA) was subsequently chosen, based on its potent biofilm inhibition effect as observed in crystal violet staining. Therefore, the aim of this study was to investigate the specific effects of TA on the biofilm formation of clinically isolated Escherichia coli (E. coli). Results demonstrated a significant inhibition of E. coli Ec032 biofilm formation by TA, while not substantially affecting the biofilm of the ΔcsgD strain. Moreover, deletion of the csgD gene led to a reduction in Ec032 biofilm formation, alongside diminished bacterial motility and curli synthesis inhibition. Transcriptomic analysis and RT-qPCR revealed that TA repressed genes associated with the csg operon and other biofilm-related genes. In conclusion, our results suggest that CsgD is one of the key targets for TA to inhibit E. coli biofilm formation. This work preliminarily elucidates the molecular mechanisms of TA inhibiting E. coli biofilm formation, which could provide a lead structure for the development of future antibiofilm drugs.

Keywords: Biofilm; Curli; Escherichia coli; Indole; Tannic acid.