Structures and biological activity of phosphorylated dihydroceramides of Porphyromonas gingivalis.
Porphyromonas gingivalis, a recognized periodontal pathogen, synthesizes free ceramides as well as other phosphorylated ceramide lipids. The purpose of this study was to separate complex lipids of P. gingivalis by high-performance liquid chromatography (HPLC) and determine the structures and biological activities of the major ceramide classes. Using gas chromatography-mass spectrometry, electrospray tandem mass spectrometry (ESI-MS/MS) and NMR analyses, three major classes of dihydroceramides were identified in specific HPLC fractions, with all classes containing the same dihydroceramide base structures (3-OH isoC(17:0) in amide linkage to saturated long-chain bases of 17, 18, or 19 carbons). The free dihydroceramide class recovered in HPLC fractions 7-8 revealed little biological activity. HPLC fraction 20 dihydroceramides, substituted with 1-O-phosphoglycerol and isoC(15:0) linked to the hydroxyl of 3-OH isoC(17:0), significantly potentiated interleukin-1beta (IL-1beta)-mediated prostaglandin secretion and produced marked alterations in fibroblast morphology. HPLC fraction 28 dihydroceramides, substituted with 1-O-phosphoethanolamine, demonstrated little capacity to potentiate IL-1beta-mediated prostaglandin secretion. The novel phosphorylated dihydroceramides synthesized by P. gingivalis demonstrate varying biological activities based on the phosphorylated head group substitution and/or the addition of esterified fatty acid. These results also demonstrate the strong virulence capacity of phosphoglycerol dihydroceramides of P. gingivalis to promote inflammatory factor secretion from IL-1beta-treated fibroblasts and to produce marked alterations in cell morphology in culture.
Department of Periodontology, University of Connecticut School of Dental Medicine, 263 Farmington Avenue, Farmington, CT, USA. nichols@nso.uchc.edu
Frank C
FC
Nichols
Birgit
B
Riep
JiYoung
J
Mun
Martha D
MD
Morton
Mike T
MT
Bojarski
Floyd E
FE
Dewhirst
Michael B
MB
Smith
D002518:Ceramides / Q000737:chemistry / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D005881:Gingiva / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D016966:Porphyromonas gingivalis / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization
D002518:Ceramides; C109343:dihydroceramide