Nitric oxide production and inducible nitric oxide synthase expression induced byPrevotella nigrescenslipopolysaccharide

Abstract

We have examined the effects of lipopolysaccharide (LPS) from Prevotella nigrescens, one of the causative agents of inflammatory periodontal disease and endodontic infections, on the production of nitric oxide (NO) and expression of inducible nitric oxide synthase (iNOS) in the murine macrophage cell line RAW264.7. We also attempted to throw light on the signaling mechanisms involved in P. nigrescens LPS-induced NO production. We found that P. nigrescens LPS can induce iNOS expression and stimulate the release of NO without additional stimuli and demonstrated an important role of the transcription factor NF-kappaB and microtubule polymerization in NO production. The production of NO required l-arginine and protein tyrosine kinase but not activation of protein kinase C. The ability of P. nigrescens LPS to promote the production of NO may be important in the pathogenesis of inflammatory periodontal disease and endodontic infections.

Porphyromonas gingivalis, Gamma Interferon, and a Proapoptotic Fibronectin Matrix Form a Synergistic Trio That Induces c-Jun N-Terminal Kinase 1-Mediated Nitric Oxide Generation and Cell Death

“…Reported mechanisms in the activation of nitric oxide include the activation of mitogen-activated protein kinase family members, including p38 and the transcription factor NF-B (24,41,42). However, there are no reports that have examined the role of the ECM in regulating nitric oxide and iNOS in inflammatory conditions, including periodontal disease.…”

Histological and immunohistochemical evaluation of the peri-implant soft tissues around machined and acid-etched titanium healing abutments: a prospective randomised study

“…Nitric oxide (NO) is a free radical that has been implicated in osteoclast function under normal and pathologic conditions [29]. Three different isoforms of NOS have been described: Endothelial NOS (eNOS or NOS1) and neuronal NOS (nNOS or NOS3) are called constitutive because they are essentially expressed and continuously and functionally modulated [20,[25][26][27][28][29][30][31][32][33][34][35][36]. The third isoform is an inducible isoenzyme (iNOS or NOS2).…”

Nitric oxide production and inducible nitric oxide synthase expression induced by Porphyromonas gingivalis lipopolysaccharide

“…Macrophages, polymorphonuclear cells and fibroblasts are the sources of iNOS in periodontal tissues, with endothelial cells also contributing [14][15][16][17] . Moreover, LPS from Actinobacillus actinomycetemcomitans, a major pathogen of early-onset periodontitis, induced significant production of NO in macrophages 18,19) , and LPSs from Prevotella intermedia and Prevotella nigrescens, the causative agents of inflammatory periodontal disease, fully induced iNOS expression and NO production in the murine macrophage cell line RAW264.7 cells in the absence of other stimuli 20,21) .…”