Zinc uptake system ZnuACB is essential for maintaining pathogenic phenotype of F4ac+ enterotoxigenic E. coli (ETEC) under a zinc restricted environment

Guomei Quan,Siqi Lian,Pengpeng Xia,Guoqiang Zhu,Yunping Wu

doi:10.1186/s13567-020-00854-1

Guomei Quan, Siqi Lian + Show 3 more

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https://doi.org/10.1186/s13567-020-00854-1

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Journal: Veterinary Research	Publication Date: Oct 7, 2020
Citations: 12	License type: open-access

Affiliation: Yangzhou University

Abstract

Zinc is the second trace element of living organisms after iron. Given its crucial importance, mammalian hosts restrict the bioavailability of Zinc ions (Zn2+) to bacterial pathogens. As a countermeasure, pathogens utilize high affinity Zn2+ transporters, such as ZnuACB to compete with the host for zinc. It is essential for bacteria to maintain zinc homeostasis and thus maintain their physiology and pathogenesis. In an attempt to uncover the zinc transporter in F4+ enterotoxigenic E. coli (ETEC) C83902, we analyzed two RNA-seq data sets of bacteria samples when different zinc treatments (restriction or abundance) were applied. Considering data revealing that the high affinity zinc uptake system ZnuACB acts as the main transporter in ETEC C83902 to resist zinc deficiency, we deleted znuACB genes to study the role of them in ETEC C83902. The deletion of znuACB genes results in growth perturbation and a sharp decrease in the ability of biofilm formation and adhesion of bacteria in vitro. Taking the data together, this study demonstrates that the ZnuACB system is required for ETEC C83902 to acquire zinc, which highly contributes to ETEC pathogenicity as well.

Highlights

F4+ enterotoxigenic E. coli (ETEC) is a kind of motile Gram-negative bacteria, consisting of three fimbrial variants F4ab, F4ac and F4ad. F4+ ETEC infection causes diarrhea of neonatal and post-weaned piglets in clinical practice, leading to serious economic losses in the swine industry [1, 2]
We demonstrate that the ZnuACB system is required for F4ac+ ETEC growth, and is sufficient to maintain bacterial biofilm formation and adhesion to porcine neonatal jejunal epithelial cell line (IPEC-J2) cells in vitro under zinc deficiency
The ZnuACB system contributes to zinc acquisition under zinc deficiency conditions To identify differentially expressed genes (DEG) under zinc abundant and zinc restricted conditions, we used RNA-seq technology to detect the most upregulated and downregulated genes of ETEC C83902 in LB medium with 30 μM TPEN than those in the supplemented with 1 mM ZnSO4 LB medium

Summary

Introduction

F4+ enterotoxigenic E. coli (ETEC) is a kind of motile Gram-negative bacteria, consisting of three fimbrial variants F4ab, F4ac and F4ad. F4+ ETEC infection causes diarrhea of neonatal and post-weaned piglets in clinical practice, leading to serious economic losses in the swine industry [1, 2]. F4+ enterotoxigenic E. coli (ETEC) is a kind of motile Gram-negative bacteria, consisting of three fimbrial variants F4ab, F4ac and F4ad. F4+ ETEC infection causes diarrhea of neonatal and post-weaned piglets in clinical practice, leading to serious economic losses in the swine industry [1, 2]. Zinc is a second essential trace element in living organisms, including mammalians, bacteria, and plants, etc. It has different functions, such as a structural component, catalytic factor of molecules or proteins, and plays significant roles in cell growth, transcription, cell division, response to oxidative stress, apoptosis, and aging [4]. Mammalian macrophages can reorganize zinc concentration after phagocytosis, killing pathogens by zinc starvation or zinc toxicity

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