Inositol-phosphodihydroceramides in the periodontal pathogen Tannerella forsythia: Structural analysis and incorporation of exogenous myo-inositol.
BACKGROUND
Unique phosphodihydroceramides containing phosphoethanolamine and glycerol have been previously described in Porphyromonas gingivalis. Importantly, they were shown to possess pro-inflammatory properties. Other common human bacteria were screened for the presence of these lipids, and they were found, amongst others, in the oral pathogen Tannerella forsythia. To date, no detailed study into the lipids of this organism has been performed.


METHODS
Lipids were extracted, separated and purified by HPTLC, and analyzed using GC-MS, ESI-MS and NMR. Of special interest was how T. forsythia acquires the metabolic precursors for the lipids studied here. This was assayed by radioactive and stable isotope incorporation using carbon-14 and deuterium labeled myo-inositol, added to the growth medium.


RESULTS
T. forsythia synthesizes two phosphodihydroceramides (Tf GL1, Tf GL2) which are constituted by phospho-myo-inositol linked to either a 17-, 18-, or 19-carbon sphinganine, N-linked to either a branched 17:0(3-OH) or a linear 16:0(3-OH) fatty acid which, in Tf GL2, is, in turn, ester-substituted with a branched 15:0 fatty acid. T. forsythia lacks the enzymatic machinery required for myo-inositol synthesis but was found to internalize inositol from the medium for the synthesis of both Tf GL1 and Tf GL2.


CONCLUSIONS
The study describes two novel glycolipids in T. forsythia which could be essential in this organism. Their synthesis could be reliant on an external source of myo-inositol.


CONCLUSIONS
The effects of these unique lipids on the immune system and their role in bacterial virulence could be relevant in the search for new drug targets.
Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, 1190 Vienna, Austria.
Zoë Anne
ZA
Megson
Institute of Chemical Technologies and Analytics, Vienna, University of Technology, Getreidemarkt 9, 1060 Vienna, Austria.
Ernst
E
Pittenauer
Department of Structural Biochemistry, Priority Area Asthma & Allergy, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a/4c, 23845 Borstel, Germany.
Katarzyna Anna
KA
Duda
Department of Structural Biochemistry, Priority Area Asthma & Allergy, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a/4c, 23845 Borstel, Germany.
Regina
R
Engel
Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, 1190 Vienna, Austria; Institute of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 38, 1090 Vienna, Austria.
Karin
K
Ortmayr
Institute of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 38, 1090 Vienna, Austria.
Gunda
G
Koellensperger
Department of Applied Genetics and Cell Biology, Universität für Bodenkultur Wien, Muthgasse 18, 1190 Vienna, Austria.
Lukas
L
Mach
Institute of Chemical Technologies and Analytics, Vienna, University of Technology, Getreidemarkt 9, 1060 Vienna, Austria.
Günter
G
Allmaier
Department of Structural Biochemistry, Priority Area Asthma & Allergy, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a/4c, 23845 Borstel, Germany.
Otto
O
Holst
Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, 1190 Vienna, Austria.
Paul
P
Messner
Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, 1190 Vienna, Austria. Electronic address: christina.schaeffer@boku.ac.at.
Christina
C
Schäffer
D001438:Bacteroidaceae / Q000737:chemistry / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002518:Ceramides / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003903:Deuterium; D004983:Ethanolamines / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D005990:Glycerol / Q000032:analysis / Q000737:chemistry; D007294:Inositol / Q000378:metabolism*; D007553:Isotope Labeling; D059625:Liquid-Liquid Extraction; D009682:Magnetic Resonance Spectroscopy; D013110:Sphingosine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
D002250:Carbon Radioisotopes; D002518:Ceramides; D004983:Ethanolamines; D007294:Inositol; C005448:phosphorylethanolamine; D003903:Deuterium; D013110:Sphingosine; C005682:safingol; D005990:Glycerol
Dihydroceramides; ESI–MS; Inositol uptake; Myo-inositol; NMR; Tannerella forsythia