Porphyromonas gingivalis lipopolysaccharide interferes with salivary mucin synthesis through inducible nitric oxide synthase activation by ERK and p38 kinase.
Porphyromonas gingivalis is a Gram-negative periodontopathic bacterium colonizing the oral cavity and its lipopolysaccharide (LPS) is a key factor in the development of periodontitis. We investigated the effect of P. gingivalis LPS on the cellular responses associated with mucin synthesis in sublingual salivary gland acinar cells. Exposure of the acinar cells to the LPS led to a dose-dependent decrease in mucin synthesis and was accompanied by a massive induction in inducible nitric oxide synthase (NOS-2) activity and the increase in NO production, caspase-3 activity and apoptosis. Inhibition of extracellular signal-regulated kinase (ERK) with PD98059 accelerated the LPS-induced decrease in the glycoprotein synthesis and caused further increase in apoptosis and NOS-2 activity, while the blockade of p38 mitogen-activated kinase (MAPK) with SB203580 countered the LPS-induced reduction in the glycoprotein synthesis and obviated the induced increases in NOS-2 and apoptosis. Introduction of NOS-2 inhibitor, L-NAME, not only countered the LPS-induced increase in NO generation, caspase-3 activity and apoptosis, but caused the impedance of the LPS inhibition on mucin synthesis. The findings point to the upregulation in NOS-2 expression by P. gingivalis LPS as a key detrimental culprit affecting salivary mucin synthesis.
Slomiany
Bronislaw L
BL
Research Center, C875, University of Medicine and Dentistry of New Jersey-New Jersey Dental School, 110 Bergen Street, P.O. Box 1709, Newark, NJ 07103-2400, USA. slomiabr@umdnj.edu
Slomiany
Amalia
A
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000378:metabolism* / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009077:Mucins / Q000096:biosynthesis*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D016966:Porphyromonas gingivalis / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012463:Saliva / Q000378:metabolism*; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D008070:Lipopolysaccharides; D009077:Mucins; D011725:Pyridines; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D019331:NG-Nitroarginine Methyl Ester