Abstract
One of the unique features of Helicobacter pylori is its ability to assimilate free-cholesterol (FC) into its membranes. Via FC assimilation, H. pylori strengthens the membrane lipid barrier and/or evades the host immune system. No previous studies, however, have investigated the FC uptake mechanisms of the H. pylori cell. Phosphatidylethanolamine (PE) is the most prevalent lipid component of bacteria, including H. pylori, but the function of PE remains unclear. We were therefore interested in H. pylori PE (HpPE) and investigated the interaction of its PE with cholesterols. The PE isolated from H. pylori underwent a unique molecular interaction with FC, cholesterol ester (CE), and 2,6-di-O-methyl-β-cyclodextrin (dMßCD), a sterol solubilizer. HpPE interacted not only with the FC molecule, but also with the FC-dMβCD inclusion complex. In contrast, Escherichia coli PE (EcPE), prepared as a reference PE, seemed to bind only FC, and only via a hydrophobic interaction, without binding dMβCD. HpPE was clearly more potent than EcPE in binding FC. Intriguingly, HpPE had a negligible affinity for CE, while EcPE had a high affinity for CE, comparable to its affinity for FC. Further, HpPE interacted with 3β-OH steroids, pregnenolone and dehydroepiandrosterone, in the absence of dMβCD. Gas chromatogram-mass spectrometry (GC-MS) and liquid chromatographymass spectrometry (LC-MS) analyses revealed that the fatty acid compositions of HpPE were quite distinct from those of EcPE, and the C14:0 fatty acid in the HpPE molecule was found to be significant in binding FC selectively. These results indicate that PE is a key candidate of nonesterified steroid-binding lipids in H. pylori.
| Original language | English |
|---|---|
| Pages (from-to) | 2658-2667 |
| Number of pages | 10 |
| Journal | Journal of Bacteriology |
| Volume | 194 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - May 2012 |
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ASJC Scopus subject areas
- Microbiology
- Molecular Biology
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Phosphatidylethanolamine of Helicobacter pylori functions as a steroid-binding lipid in the assimilation of free cholesterol and 3β-hydroxl steroids into the bacterial cell membrane. / Shimomura, Hirofumi; Hosoda, Kouichi; Hayashi, Shunji; Yokota, Kenji; Hirai, Yoshikazu.
In: Journal of Bacteriology, Vol. 194, No. 10, 05.2012, p. 2658-2667.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Phosphatidylethanolamine of Helicobacter pylori functions as a steroid-binding lipid in the assimilation of free cholesterol and 3β-hydroxl steroids into the bacterial cell membrane
AU - Shimomura, Hirofumi
AU - Hosoda, Kouichi
AU - Hayashi, Shunji
AU - Yokota, Kenji
AU - Hirai, Yoshikazu
PY - 2012/5
Y1 - 2012/5
N2 - One of the unique features of Helicobacter pylori is its ability to assimilate free-cholesterol (FC) into its membranes. Via FC assimilation, H. pylori strengthens the membrane lipid barrier and/or evades the host immune system. No previous studies, however, have investigated the FC uptake mechanisms of the H. pylori cell. Phosphatidylethanolamine (PE) is the most prevalent lipid component of bacteria, including H. pylori, but the function of PE remains unclear. We were therefore interested in H. pylori PE (HpPE) and investigated the interaction of its PE with cholesterols. The PE isolated from H. pylori underwent a unique molecular interaction with FC, cholesterol ester (CE), and 2,6-di-O-methyl-β-cyclodextrin (dMßCD), a sterol solubilizer. HpPE interacted not only with the FC molecule, but also with the FC-dMβCD inclusion complex. In contrast, Escherichia coli PE (EcPE), prepared as a reference PE, seemed to bind only FC, and only via a hydrophobic interaction, without binding dMβCD. HpPE was clearly more potent than EcPE in binding FC. Intriguingly, HpPE had a negligible affinity for CE, while EcPE had a high affinity for CE, comparable to its affinity for FC. Further, HpPE interacted with 3β-OH steroids, pregnenolone and dehydroepiandrosterone, in the absence of dMβCD. Gas chromatogram-mass spectrometry (GC-MS) and liquid chromatographymass spectrometry (LC-MS) analyses revealed that the fatty acid compositions of HpPE were quite distinct from those of EcPE, and the C14:0 fatty acid in the HpPE molecule was found to be significant in binding FC selectively. These results indicate that PE is a key candidate of nonesterified steroid-binding lipids in H. pylori.
AB - One of the unique features of Helicobacter pylori is its ability to assimilate free-cholesterol (FC) into its membranes. Via FC assimilation, H. pylori strengthens the membrane lipid barrier and/or evades the host immune system. No previous studies, however, have investigated the FC uptake mechanisms of the H. pylori cell. Phosphatidylethanolamine (PE) is the most prevalent lipid component of bacteria, including H. pylori, but the function of PE remains unclear. We were therefore interested in H. pylori PE (HpPE) and investigated the interaction of its PE with cholesterols. The PE isolated from H. pylori underwent a unique molecular interaction with FC, cholesterol ester (CE), and 2,6-di-O-methyl-β-cyclodextrin (dMßCD), a sterol solubilizer. HpPE interacted not only with the FC molecule, but also with the FC-dMβCD inclusion complex. In contrast, Escherichia coli PE (EcPE), prepared as a reference PE, seemed to bind only FC, and only via a hydrophobic interaction, without binding dMβCD. HpPE was clearly more potent than EcPE in binding FC. Intriguingly, HpPE had a negligible affinity for CE, while EcPE had a high affinity for CE, comparable to its affinity for FC. Further, HpPE interacted with 3β-OH steroids, pregnenolone and dehydroepiandrosterone, in the absence of dMβCD. Gas chromatogram-mass spectrometry (GC-MS) and liquid chromatographymass spectrometry (LC-MS) analyses revealed that the fatty acid compositions of HpPE were quite distinct from those of EcPE, and the C14:0 fatty acid in the HpPE molecule was found to be significant in binding FC selectively. These results indicate that PE is a key candidate of nonesterified steroid-binding lipids in H. pylori.
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UR - http://www.scopus.com/inward/citedby.url?scp=84861414398&partnerID=8YFLogxK
U2 - 10.1128/JB.00105-12
DO - 10.1128/JB.00105-12
M3 - Article
C2 - 22408164
AN - SCOPUS:84861414398
VL - 194
SP - 2658
EP - 2667
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
IS - 10
ER -