Phosphatidylethanolamine, but not Phosphatidylglycerol‐Cardiolipin, Isolated from Two Species of Helicobacter Binds Cholesterol over Cholesteryl Ester

Abstract

This study demonstrated that the cells of Helicobacter felis and Helicobacter cinaedi spontaneously absorb cholesterol added to the medium. A recent study by our group has revealed that phosphatidylethanolamine (PtdEtn) of Helicobacter pylori contains myristic acid as the most predominant saturated fatty acid and that the PtdEtn of this bacterium binds cholesterol more selectively than cholesteryl ester. We, therefore, isolated the PtdEtn from the two Helicobacter species to analyze the hydrophobic interaction between cholesterol and its glycerophospholipid. PtdEtn of the Helicobacter bacteria interacted more selectively with cholesterol than with cholesteryl ester, and the degree of the selective binding of cholesterol was higher in the PtdEtn than in the phosphatidylglycerol-cardiolipin of the same bacteria. These results suggest the possibility that the cells of H. felis and H. cinaedi may contain abundant PtdEtn with myristic acid. On this basis, we analyzed the PtdEtn molecular species of the Helicobacter bacteria and demonstrated that the PtdEtn containing myristic acid accounts for more than 35% in the total PtdEtn. These results suggest that the myristoyl PtdEtn takes part in the absorption of cholesterol in H. felis and H. cinaedi.

Indene Compounds Synthetically Derived from Vitamin D Have Selective Antibacterial Action on Helicobacter pylori

“…A recent study by our group has revealed that PtdEtn of H. felis and H. cinaedi abundantly contains a 14:0 fatty‐acid side chain and the composition of PtdEtn molecular species was similar between the two Helicobacter species (Amgalanbaatar et al, ). We, therefore, examined the bactericidal action of the indene compound (VDP1) against the two Helicobacter species to clarify the significance of a 14:0 fatty‐acid side‐chain in PtdEtn molecules on contribution to its action.…”

“…Persons infected with this bacterium occasionally suffer from systematic inflammations due to the bacteremia (Kawamura et al, ). Recent studies by our group have demonstrated that the PtdEtn of these Helicobacter species including H. pylori functions as a cholesterol‐binding lipid and strongly suggested that the 14:0 fatty‐acid side‐chain in the PtdEtn molecule contributes to the selective binding affinity for cholesterol but not cholesteryl ester (Amgalanbaatar et al, ; Shimomura et al, ). Intriguingly, H. cinaedi cells assimilated exogenous cholesterol at less amounts than H. felis cells, but the cholesterol‐binding capability of PtdEtn extracted from H. cinaedi was comparable to the capability of PtdEtn extracted from H. felis .…”

“…This study examined three Helicobacter species ( H. pylori strain NCTC 11638, Helicobacter felis strain ATCC 49179, and Helicobacter cinaedi strain 1193) and seven commonplace bacterial species ( Escherichia coli strain ATCC 11775, P. aeruginosa strain ATCC 10145, S. aureus strain FDA 209D, Klebsiella pneumoniae , Serratia marcescens , Proteus mirabilis , and Salmonella enterica subsp. enterica serovar Typhimurium) (Amgalanbaatar, Hosoda, & Shimomura, ; Hosoda et al, ). The K. pneumoniae , S. marcescens , P. mirabilis , and Salmonella sp.…”

Development of a Novel Antibacterial Medicine that Targets a Characteristic Lipid of the Cell Membranes ofHelicobacter pylori

“…In contrast, Helicobacter cinaedi showed low susceptibility to the bacteriolytic action of VDP1, even though the PE molecular species composition in H. cinaedi is similar to the PE molecular species composition in H. felis [39]. H. cinaedi is a Gram-negative rod-like bacillus equipped with bipolar flagella and isolated from the intestinal tracts and livers of various mammals such as human, dog, cat, and hamster [40][41][42].…”

“…As seen in H. pylori, H. felis causes chronic gastritis and gastric MALT lymphoma in mouse when it colonizes the mouse stomach [37,38]. An earlier study by our group has revealed that a myristic acid accounts for approximately 16% in the fatty acid composition of H. felis PE, and that the PE molecular species retaining a myristic acid and a palmitic acid accounts for approximately 37% in total PE molecular species of the bacteria [39]. Though H. felis completely succumbs to the bacteriolytic action at the same concentration of VDP1 (less than 3 μg/ml) that eradicates H. pylori, this Helicobacter species did not possess DMPE.…”