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The role of full-length apoE in clearance of Gram-negative bacteria and their endotoxins

Petruk, Ganna LU orcid ; Elvén, Malin LU ; Hartman, Erik LU orcid ; Davoudi, Mina LU orcid ; Schmidtchen, Artur LU ; Puthia, Manoj LU and Petrlova, Jitka LU (2021) In Journal of Lipid Research 62.
Abstract

ApoE is a well-known lipid-binding protein that plays a main role in the metabolism and transport of lipids. More recently, apoE-derived peptides have been shown to exert antimicrobial effects. Here, we investigated the antibacterial activity of apoE using in vitro assays, advanced imaging techniques, and in vivo mouse models. The formation of macromolecular complexes of apoE and endotoxins from Gram-negative bacteria was explored using gel shift assays, transmission electron microscopy, and CD spectroscopy followed by calculation of the α-helical content. The binding affinity of apoE to endotoxins was also confirmed by fluorescent spectroscopy detecting the quenching and shifting of tryptophan intrinsic fluorescence. We showed that... (More)

ApoE is a well-known lipid-binding protein that plays a main role in the metabolism and transport of lipids. More recently, apoE-derived peptides have been shown to exert antimicrobial effects. Here, we investigated the antibacterial activity of apoE using in vitro assays, advanced imaging techniques, and in vivo mouse models. The formation of macromolecular complexes of apoE and endotoxins from Gram-negative bacteria was explored using gel shift assays, transmission electron microscopy, and CD spectroscopy followed by calculation of the α-helical content. The binding affinity of apoE to endotoxins was also confirmed by fluorescent spectroscopy detecting the quenching and shifting of tryptophan intrinsic fluorescence. We showed that apoE exhibits antibacterial activity particularly against Gram-negative bacteria such as Pseudomonas aeruginosa and Escherichia coli. ApoE protein folding was affected by binding of bacterial endotoxin components such as lipopolysaccharide (LPS) and lipid A, yielding similar increases in the apoE α-helical content. Moreover, high-molecular-weight complexes of apoE were formed in the presence of LPS, but not to the same extent as with lipid A. Together, our results demonstrate the ability of apoE to kill Gram-negative bacteria, interact with their endotoxins, which leads to the structural changes in apoE and the formation of aggregate-like complexes.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Aggregation, Antimicrobial peptides, Bacteria, CD, Host defense, Infection, Innate immunity, Lipid A, Lipopolysaccharide
in
Journal of Lipid Research
volume
62
article number
100086
publisher
American Society for Biochemistry and Molecular Biology
external identifiers
  • pmid:34019903
  • scopus:85110934485
ISSN
0022-2275
DOI
10.1016/J.JLR.2021.100086
language
English
LU publication?
yes
id
7eebd686-5785-4430-8944-fcadb7d87d8f
date added to LUP
2021-08-31 15:15:03
date last changed
2025-04-04 14:35:26
@article{7eebd686-5785-4430-8944-fcadb7d87d8f,
  abstract     = {{<p>ApoE is a well-known lipid-binding protein that plays a main role in the metabolism and transport of lipids. More recently, apoE-derived peptides have been shown to exert antimicrobial effects. Here, we investigated the antibacterial activity of apoE using in vitro assays, advanced imaging techniques, and in vivo mouse models. The formation of macromolecular complexes of apoE and endotoxins from Gram-negative bacteria was explored using gel shift assays, transmission electron microscopy, and CD spectroscopy followed by calculation of the α-helical content. The binding affinity of apoE to endotoxins was also confirmed by fluorescent spectroscopy detecting the quenching and shifting of tryptophan intrinsic fluorescence. We showed that apoE exhibits antibacterial activity particularly against Gram-negative bacteria such as Pseudomonas aeruginosa and Escherichia coli. ApoE protein folding was affected by binding of bacterial endotoxin components such as lipopolysaccharide (LPS) and lipid A, yielding similar increases in the apoE α-helical content. Moreover, high-molecular-weight complexes of apoE were formed in the presence of LPS, but not to the same extent as with lipid A. Together, our results demonstrate the ability of apoE to kill Gram-negative bacteria, interact with their endotoxins, which leads to the structural changes in apoE and the formation of aggregate-like complexes.</p>}},
  author       = {{Petruk, Ganna and Elvén, Malin and Hartman, Erik and Davoudi, Mina and Schmidtchen, Artur and Puthia, Manoj and Petrlova, Jitka}},
  issn         = {{0022-2275}},
  keywords     = {{Aggregation; Antimicrobial peptides; Bacteria; CD; Host defense; Infection; Innate immunity; Lipid A; Lipopolysaccharide}},
  language     = {{eng}},
  month        = {{01}},
  publisher    = {{American Society for Biochemistry and Molecular Biology}},
  series       = {{Journal of Lipid Research}},
  title        = {{The role of full-length apoE in clearance of Gram-negative bacteria and their endotoxins}},
  url          = {{http://dx.doi.org/10.1016/J.JLR.2021.100086}},
  doi          = {{10.1016/J.JLR.2021.100086}},
  volume       = {{62}},
  year         = {{2021}},
}