HldE Is Important for Virulence Phenotypes in Enterotoxigenic Escherichia coli

Grith M. Maigaard Hermansen, Anders Boysen, Thøger J. Krogh, Arkadiusz Nawrocki, Lars Jelsbak, Jakob Møller-Jensen*

*Corresponding author for this work

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Abstract

Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrheal illness in third world countries and it especially affects children and travelers visiting these regions. ETEC causes disease by adhering tightly to the epithelial cells in a concerted effort by adhesins, flagella, and other virulence-factors. When attached ETEC secretes toxins targeting the small intestine host-cells, which ultimately leads to osmotic diarrhea. HldE is a bifunctional protein that catalyzes the nucleotide-activated heptose precursors used in the biosynthesis of lipopolysaccharide (LPS) and in post-translational protein glycosylation. Both mechanisms have been linked to ETEC virulence: Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane and is needed for transport of heat-labile toxins to the host cells, and ETEC glycoproteins have been shown to play an important role for bacterial adhesion to host epithelia. Here, we report that HldE plays an important role for ETEC virulence. Deletion of hldE resulted in markedly reduced binding to the human intestinal cells due to reduced expression of colonization factor CFA/I on the bacterial surface. Deletion of hldE also affected ETEC motility in a flagella-dependent fashion. Expression of both colonization factors and flagella was inhibited at the level of transcription. In addition, the hldE mutant displayed altered growth, increased biofilm formation and clumping in minimal growth medium. Investigation of an orthogonal LPS-deficient mutant combined with mass spectrometric analysis of protein glycosylation indicated that HldE exerts its role on ETEC virulence both through protein glycosylation and correct LPS configuration. These results place HldE as an attractive target for the development of future antimicrobial therapeutics.
Original languageEnglish
Article number253
JournalFrontiers in Cellular and Infection Microbiology
Volume8
Issue number253
Number of pages13
ISSN2235-2988
DOIs
Publication statusPublished - 2018

Bibliographical note

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)

Keywords

  • ADP-l-glycero-β-d-manno-heptose
  • Biofilm formation
  • Enterotoxigenic Escherichia coli
  • HldE
  • Lipopolysaccharide
  • Motility
  • Transmission electron microscopy
  • Virulence factors

Cite this

Maigaard Hermansen, Grith M. ; Boysen, Anders ; Krogh, Thøger J. ; Nawrocki, Arkadiusz ; Jelsbak, Lars ; Møller-Jensen, Jakob. / HldE Is Important for Virulence Phenotypes in Enterotoxigenic Escherichia coli. In: Frontiers in Cellular and Infection Microbiology. 2018 ; Vol. 8, No. 253.
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title = "HldE Is Important for Virulence Phenotypes in Enterotoxigenic Escherichia coli",
abstract = "Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrheal illness in third world countries and it especially affects children and travelers visiting these regions. ETEC causes disease by adhering tightly to the epithelial cells in a concerted effort by adhesins, flagella, and other virulence-factors. When attached ETEC secretes toxins targeting the small intestine host-cells, which ultimately leads to osmotic diarrhea. HldE is a bifunctional protein that catalyzes the nucleotide-activated heptose precursors used in the biosynthesis of lipopolysaccharide (LPS) and in post-translational protein glycosylation. Both mechanisms have been linked to ETEC virulence: Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane and is needed for transport of heat-labile toxins to the host cells, and ETEC glycoproteins have been shown to play an important role for bacterial adhesion to host epithelia. Here, we report that HldE plays an important role for ETEC virulence. Deletion of hldE resulted in markedly reduced binding to the human intestinal cells due to reduced expression of colonization factor CFA/I on the bacterial surface. Deletion of hldE also affected ETEC motility in a flagella-dependent fashion. Expression of both colonization factors and flagella was inhibited at the level of transcription. In addition, the hldE mutant displayed altered growth, increased biofilm formation and clumping in minimal growth medium. Investigation of an orthogonal LPS-deficient mutant combined with mass spectrometric analysis of protein glycosylation indicated that HldE exerts its role on ETEC virulence both through protein glycosylation and correct LPS configuration. These results place HldE as an attractive target for the development of future antimicrobial therapeutics.",
keywords = "ADP-l-glycero-β-d-manno-heptose, Biofilm formation, Enterotoxigenic Escherichia coli, HldE, Lipopolysaccharide, Motility, Transmission electron microscopy, Virulence factors",
author = "{Maigaard Hermansen}, {Grith M.} and Anders Boysen and Krogh, {Th{\o}ger J.} and Arkadiusz Nawrocki and Lars Jelsbak and Jakob M{\o}ller-Jensen",
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doi = "10.3389/fcimb.2018.00253",
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HldE Is Important for Virulence Phenotypes in Enterotoxigenic Escherichia coli. / Maigaard Hermansen, Grith M.; Boysen, Anders; Krogh, Thøger J.; Nawrocki, Arkadiusz; Jelsbak, Lars; Møller-Jensen, Jakob.

In: Frontiers in Cellular and Infection Microbiology, Vol. 8, No. 253, 253, 2018.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - HldE Is Important for Virulence Phenotypes in Enterotoxigenic Escherichia coli

AU - Maigaard Hermansen, Grith M.

AU - Boysen, Anders

AU - Krogh, Thøger J.

AU - Nawrocki, Arkadiusz

AU - Jelsbak, Lars

AU - Møller-Jensen, Jakob

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PY - 2018

Y1 - 2018

N2 - Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrheal illness in third world countries and it especially affects children and travelers visiting these regions. ETEC causes disease by adhering tightly to the epithelial cells in a concerted effort by adhesins, flagella, and other virulence-factors. When attached ETEC secretes toxins targeting the small intestine host-cells, which ultimately leads to osmotic diarrhea. HldE is a bifunctional protein that catalyzes the nucleotide-activated heptose precursors used in the biosynthesis of lipopolysaccharide (LPS) and in post-translational protein glycosylation. Both mechanisms have been linked to ETEC virulence: Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane and is needed for transport of heat-labile toxins to the host cells, and ETEC glycoproteins have been shown to play an important role for bacterial adhesion to host epithelia. Here, we report that HldE plays an important role for ETEC virulence. Deletion of hldE resulted in markedly reduced binding to the human intestinal cells due to reduced expression of colonization factor CFA/I on the bacterial surface. Deletion of hldE also affected ETEC motility in a flagella-dependent fashion. Expression of both colonization factors and flagella was inhibited at the level of transcription. In addition, the hldE mutant displayed altered growth, increased biofilm formation and clumping in minimal growth medium. Investigation of an orthogonal LPS-deficient mutant combined with mass spectrometric analysis of protein glycosylation indicated that HldE exerts its role on ETEC virulence both through protein glycosylation and correct LPS configuration. These results place HldE as an attractive target for the development of future antimicrobial therapeutics.

AB - Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrheal illness in third world countries and it especially affects children and travelers visiting these regions. ETEC causes disease by adhering tightly to the epithelial cells in a concerted effort by adhesins, flagella, and other virulence-factors. When attached ETEC secretes toxins targeting the small intestine host-cells, which ultimately leads to osmotic diarrhea. HldE is a bifunctional protein that catalyzes the nucleotide-activated heptose precursors used in the biosynthesis of lipopolysaccharide (LPS) and in post-translational protein glycosylation. Both mechanisms have been linked to ETEC virulence: Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane and is needed for transport of heat-labile toxins to the host cells, and ETEC glycoproteins have been shown to play an important role for bacterial adhesion to host epithelia. Here, we report that HldE plays an important role for ETEC virulence. Deletion of hldE resulted in markedly reduced binding to the human intestinal cells due to reduced expression of colonization factor CFA/I on the bacterial surface. Deletion of hldE also affected ETEC motility in a flagella-dependent fashion. Expression of both colonization factors and flagella was inhibited at the level of transcription. In addition, the hldE mutant displayed altered growth, increased biofilm formation and clumping in minimal growth medium. Investigation of an orthogonal LPS-deficient mutant combined with mass spectrometric analysis of protein glycosylation indicated that HldE exerts its role on ETEC virulence both through protein glycosylation and correct LPS configuration. These results place HldE as an attractive target for the development of future antimicrobial therapeutics.

KW - ADP-l-glycero-β-d-manno-heptose

KW - Biofilm formation

KW - Enterotoxigenic Escherichia coli

KW - HldE

KW - Lipopolysaccharide

KW - Motility

KW - Transmission electron microscopy

KW - Virulence factors

U2 - 10.3389/fcimb.2018.00253

DO - 10.3389/fcimb.2018.00253

M3 - Journal article

VL - 8

JO - Frontiers in Cellular and Infection Microbiology

JF - Frontiers in Cellular and Infection Microbiology

SN - 2235-2988

IS - 253

M1 - 253

ER -