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Nitro-conjugated linoleic acid (NO 2 -CLA) has been observed to manifest salutary signaling responses, including anti-inflammatory and antioxidant properties. Here, the authors have explored the influence and underlying mechanisms of NO 2 -CLA on the proinflammatory reaction of murine macrophages that were challenged with lipopolysaccharide (LPS) derived from Prevotella intermedia, a putative periodontopathic bacterium. Treatment of LPS-activated RAW264.7 cells with NO 2 -CLA notably dampened the secretion of iNOS-derived NO, IL-1β and IL-6 as well as their gene expressions and significantly enhanced the markers for M2 macrophage polarization. NO 2 -CLA promoted the HO-1 expression in cells challenged with LPS, and tin protoporphyrin IX, an HO-1 inhibitor, significantly reversed the NO 2 -CLA-mediated attenuation of NO secretion, but not IL-1β or IL-6. We found that cells treated with NO 2 -CLA significantly increased mRNA expression of PPAR-γ compared to control cells, and NO 2 -CLA significantly reverted the decrease in PPAR-γ mRNA caused by LPS. Nonetheless, antagonists to PPAR-γ were unable to reverse the NO 2 -CLA-mediated suppression of inflammatory mediators. In addition, NO 2 -CLA did not alter the p38 and JNK activation elicited by LPS. Both NF-κB reporter activity and IκB-α degradation caused by LPS were notably diminished by NO 2 -CLA. NO 2 -CLA was observed to interrupt the nuclear translocation and DNA binding of p50 subunits caused by LPS with no obvious alterations in p65 subunits. Further, NO 2 -CLA attenuated the phosphorylation of STAT1/3 elicited in response to LPS. We propose that NO 2 -CLA could be considered as a possible strategy for the therapy of periodontal disease, although additional researches are certainly required to confirm this., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The hypothesis of the present study was that nitro-fatty acids (NO 2 -FAs) would suppress inflammation associated with periodontal disease. To test this hypothesis, we investigated the influence of nitrooleic acid, a prototypical NO 2 -FA, on the inflammatory response of murine macrophages activated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen associated the etiology of different types of periodontal diseases. LPS was prepared from P. intermedia cells by using phenol-water protocol. Culture supernatants were assayed for nitric oxide (NO), interleukin-1β (IL-1β), and IL-6. Real-time polymerase chain reaction and immunoblotting analyses were performed to quantify messenger RNA and protein expression, respectively. The secreted embryonic alkaline phosphatase reporter assay was performed to measure NF-κB activation. The transcription factor assay kit was used to measure DNA-binding of NF-κB subunits. Findings obtained from the present study revealed that nitrooleic acid suppresses the generation and messenger RNA expression of inducible NO synthase-derived NO, IL-1β, and IL-6 in RAW264.7 cells activated with P. intermedia LPS and promotes macrophage polarization toward anti-inflammatory M2 phenotype. We also found that nitrooleic acid exerts its effect via heme oxygenase-1 induction and suppression of NF-κB signaling. The inhibition of NO and proinflammatory cytokine production by nitrooleic acid was independent from PPAR-γ, JNK, p38, and STAT1/3. Nitrooleic acid may represent a novel class of agent as a host modulator which has therapeutic benefit in periodontal disease, though more work is needed to confirm this., Competing Interests: Author declarations The authors declare that there are no conflicts of interest., (Copyright © 2022. Published by Elsevier Inc.)

Carbon monoxide (CO) is increasingly being appreciated as an important mediator that has pleiotropic biological properties and appears to have a possible therapeutic application for a variety of disorders. Nevertheless, whether this gaseous molecule may be utilized as a therapeutic intervention for periodontal disease is unclear. Here, we examined the potential beneficial effect of CO-releasing molecule-2 (CORM-2), a tricarbonyldichlororuthenium(II) dimer, against the elaboration of proinflammatory mediators by murine macrophages challenged with lipopolysaccharide (LPS) isolated from Prevotella intermedia, a pathogenic bacterium implicated in inflammatory periodontal disease. We found that NO and IL-1β production, iNOS protein expression and mRNA expressions of iNOS and IL-1β were significantly down-regulated when LPS-challenged RAW264.7 cells were exposed to CORM-2. In addition, HO-1 expression was upregulated by CORM-2 in cells activated with P. intermedia LPS, and the inhibitory influence of CORM-2 upon NO production was attenuated by tin protoporphyrin IX, an inhibitor of HO activity. PPAR-γ did not function in the attenuation of NO and IL-1β by CORM-2. JNK and p38 phosphorylation caused by LPS was not altered by CORM-2. CORM-2 reduced NF-κB reporter activity and IκB-α degradation elicited by P. intermedia LPS. Additionally, CORM-2 inhibited LPS-induced phosphorylation of STAT1/3. In conclusion, CORM-2 suppresses NO and IL-1β production caused by P. intermedia LPS. CORM-2 exerts its effect by a mechanism involving anti-inflammatory HO-1 induction and attenuation of NF-κB and STAT1/3 activation, independently of PPAR-γ as well as JNK and p38. CORM-2 may hold promise as host response modulation agent for periodontal disease, though further research is indicated to verify the therapeutic effect., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Nifedipine, a calcium channel blocker, has been reported to possess anti-inflammatory and immunosuppressive effects. The current study was undertaken to explore the influence of nifedipine on the generation of proinflammatory mediators by murine macrophages activated by lipopolysaccharide (LPS) prepared from Prevotella intermedia, a putative periodontal pathogen, and associated mechanisms of action as well. LPS was purified by employing phenol-water extraction protocol. Culture supernatants were analyzed for nitric oxide (NO) and interleukin (IL)-1β. Real-time PCR and immunoblotting were conducted to quantify mRNA and protein expression, respectively. NF-κB-dependent secreted embryonic alkaline phosphatase (SEAP) levels were estimated by reporter assay. Nifedipine markedly suppressed the generation of iNOS-derived NO and IL-1β together with their mRNA expressions in murine macrophages activated by P. intermedia LPS. LPS-stimulated cells exposed to nifedipine notably increased the mRNA levels of Arg-1, Ym-1, FIZZ1, and TGF-β, which are typical markers for M2 macrophage polarization. Nifedipine induced HO-1 at both gene and protein levels in cells challenged with P. intermedia LPS, and the nifedipine-mediated inhibition of NO generation was significantly abrogated by adding SnPP, an HO-1 inhibitor. Nifedipine inhibited LPS-evoked generation of NO and IL-1β in a PPAR-γ-independent manner. In addition, NF-κB activation as well as phosphorylation of STAT1/3 induced by P. intermedia LPS was suppressed by nifedipine. Nifedipine is an inhibitor of P. intermedia LPS-evoked production of NO and IL-1β in murine macrophages and encourages macrophage polarization toward the M2 phenotype. Nifedipine possibly has potential to be used for host modulation of periodontal disease and is worth being further researched.

Aims: Josamycin has immunomodulatory properties independent of its antibacterial actions. This study was designed to explore the influences and associated mechanisms of josamycin upon the generation of proinflammatory mediators in murine macrophages activated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogenic bacterium associated with periodontal disease., Main Methods: LPS was purified by employing phenol-water extraction protocol. Culture supernatants were analyzed for nitric oxide (NO) and interleukin (IL)-1β. Real-time PCR and immunoblotting were conducted to quantify mRNA and protein expression, respectively. The expression levels of IL-1β were analyzed by confocal laser scanning microscopy. NF-κB-dependent SEAP levels were estimated by reporter assay., Key Findings: Josamycin significantly attenuated NO production elicited by P. intermedia LPS as well as induction of iNOS protein and mRNA in RAW264.7 cells. While the release of IL-1β from cells stimulated by LPS was suppressed in the presence of josamycin, josamycin failed to reduce the degree of IL-1β mRNA expression. Josamycin did not reduce the stability of IL-1β mRNA induced by P. intermedia LPS, at the same time josamycin also failed to suppress the LPS-induced intracellular IL-1β expression. Josamycin augmented HO-1 induction in cells exposed to P. intermedia LPS, and SnPP, an inhibitor of HO-1 activity, reversed the suppressive impact of josamycin upon NO generation induced by LPS. Josamycin diminished NF-κB transcriptional activity induced by P. intermedia LPS. Further, josamycin enhanced SOCS1 mRNA level in cells activated with LPS., Significance: Josamycin suppressed P. intermedia LPS-induced generation of NO and IL-1β in RAW264.7 macrophages via the inhibition of NF-κB activation as well as HO-1 and SOCS1 induction. Josamycin may have benefits as a host modulatory agent in treating periodontal disease., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

The purpose of this study was to investigate the influences of NCX 2121, a nitric oxide (NO)-releasing derivative of indomethacin, upon the generation of proinflammatory mediators using murine macrophages activated by lipopolysaccharide (LPS) isolated from Prevotella intermedia, which is one of the pathogens implicated in periodontal diseases. Inducible NO synthase (iNOS)-derived NO, IL-1β and IL-6 as well as their relevant mRNA were significantly attenuated by NCX 2121 in RAW264.7 cells activated by P. intermedia LPS. NCX 2121 was much more effective than the parental compound indomethacin in reducing these proinflammatory mediators. NCX 2121 triggered induction of heme oxygenase-1 (HO-1) in cells exposed to P. intermedia LPS, and its inhibitory influence upon P. intermedia LPS-elicited NO generation was notably blocked by SnPP treatment. NCX 2121 attenuated NF-κB-dependent SEAP release induced by P. intermedia LPS. NCX 2121 did not display inhibitory action towards IκB-α degradation triggered by LPS. Instead, it significantly diminished nuclear translocation as well as DNA-binding action of NF-κB p50 subunit elicited by P. intermedia LPS. Further, NCX 2121 significantly up-regulated SOCS1 mRNA expression in cells challenged with P. intermedia LPS. In summary, NCX 2121 down-regulates P. intermedia LPS-elicited generation of NO, IL-1β and IL-6 in murine macrophages in a mechanism that involves anti-inflammatory HO-1 induction as well as decrement of NF-κB activation, which may be associated with SOCS1 expression. NCX 2121 may have potential benefits as a host immunomodulatory agent for the therapy of periodontal disease., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: Genistein is a major isoflavone subclass of flavonoids found in soybean and a potent tyrosine kinase inhibitor. The present study aimed to assess the effect of genistein on the production of proinflammatory mediators in murine macrophages stimulated with lipopolysaccharide (LPS) isolated from Prevotella intermedia, a pathogen associated with different forms of periodontal disease, and to evaluate its possible influence on alveolar bone loss in ligature-induced periodontitis using micro-computed tomography (micro-CT) analysis as well., Design: LPS was isolated from P. intermedia ATCC 25611 by using the standard hot phenol-water method. Culture supernatants were analyzed for nitric oxide (NO) and interleukin-6 (IL-6). Inducible NO synthase (iNOS) protein expression was evaluated by immunoblot analysis. Real-time PCR was carried out to measure iNOS and IL-6 mRNA expression. In addition, effect of genistein on alveolar bone loss was evaluated in a rat model of experimental periodontitis using micro-CT analysis., Results: Genistein significantly attenuated P. intermedia LPS-induced production of iNOS-derived NO and IL-6 with attendant decrease in their mRNA expression in RAW264.7 cells. In addition, when genistein was administered to rats, decreases in alveolar bone height and bone volume fraction induced by ligature placement were significantly inhibited. Genistein administration also prevented ligature-induced alterations in the microstructural parameters of trabecular bone, including trabecular thickness, trabecular separation, bone mineral density and structure model index., Conclusions: While additional studies are required, we suggest that genistein could be utilized for the therapy of human periodontitis in the future., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In this study, the effects and underlying mechanisms of NCX 4040, a nitric oxide (NO)-donating aspirin derivative, on the production of proinflammatory mediators were examined using murine macrophages exposed to lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in the etiology of periodontal disease. NCX 4040 significantly reduced P. intermedia LPS-induced production of inducible NO synthase (iNOS)-derived NO, IL-1β and IL-6 as well as their mRNA expression in RAW264.7 cells. Notably, NCX 4040 was much more effective than the parental compound aspirin in reducing LPS-induced production of inflammatory mediators. NCX 4040 induced the expression of heme oxygenase-1 (HO-1) in cells treated with P. intermedia LPS, and the suppressive effect of NCX 4040 on LPS-induced NO production was significantly reversed by SnPP, a competitive HO-1 inhibitor. NCX 4040 did not influence LPS-induced phosphorylation of JNK and p38. IκB-α degradation as well as nuclear translocation and DNA-binding activities of NF-κB p65 and p50 subunits induced by P. intermedia LPS were significantly reduced by NCX 4040. Besides, LPS-induced phosphorylation of STAT1 and STAT3 was significantly down-regulated by NCX 4040. Further, NCX 4040 elevated the SOCS1 mRNA in cells stimulated with LPS. This study indicates that NCX 4040 inhibits P. intermedia LPS-induced production of NO, IL-1β and IL-6 in murine macrophages through anti-inflammatory HO-1 induction and suppression of NF-κB, STAT1 and STAT3 activation, which is associated with the activation of SOCS1 signaling. NCX 4040 could potentially be a promising tool in the treatment of periodontal disease, although further studies are required to verify this., (Copyright © 2015 Elsevier B.V. All rights reserved.)

This study was performed to analyze the effect of carbon monoxide (CO)-releasing molecule-3 (CORM-3) in alleviating the production of proinflammatory mediators in macrophages treated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen associated with periodontal disease, and its possible mechanisms of action. LPS was isolated using the hot phenol-water method. Culture supernatants were assayed for nitric oxide (NO) and interleukin-1β (IL-1β). Gene expression was quantified by real-time PCR, and protein expression by immunoblotting. DNA-binding activities of NF-κB subunits were determined using an ELISA-based kit. CORM-3 suppressed the production of inducible NO synthase (iNOS)-derived NO and IL-1β at both gene transcription and translation levels in P. intermedia LPS-activated RAW264.7 cells. CORM-3 enhanced heme oxygenase-1 (HO-1) expression in cells stimulated with P. intermedia LPS, and inhibition of HO-1 activity by SnPP notably reversed the suppressive effect of CORM-3 on LPS-induced production of NO. LPS-induced phosphorylation of p38 and JNK was not affected by CORM-3. CORM-3 did not influence P. intermedia LPS-induced degradation of IκB-α. Instead, nuclear translocation of NF-κB p65 and p50 subunits was blocked by CORM-3 in LPS-treated cells. In addition, CORM-3 reduced LPS-induced p65 and p50 binding to DNA. Besides, CORM-3 significantly suppressed P. intermedia LPS-induced phosphorylation of STAT1. Overall, this study indicates that CORM-3 suppresses the production of NO and IL-1β in P. intermedia LPS-activated murine macrophages via HO-1 induction and inhibition of NF-κB and STAT1 pathways. The modulation of host inflammatory response by CORM-3 would be an attractive therapeutic approach to attenuate the progression of periodontal disease., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Interleukin-6 (IL-6) is a key proinflammatory cytokine which plays a central role in the pathogenesis of periodontal disease. Host modulatory agents targeting at inhibiting IL-6, therefore, appear to be beneficial in slowing the progression of periodontal disease and potentially reducing destructive aspects of the host response. The present study was designed to investigate the effect of the macrolide antibiotic azithromycin on IL-6 generation in murine macrophages treated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in inflammatory periodontal disease, and its mechanisms of action. Azithromycin significantly suppressed IL-6 production as well as its mRNA expression in P. intermedia LPS-activated RAW264.7 cells. LPS-induced activation of JNK and p38 was not affected by azithromycin treatment. Azithromycin failed to prevent P. intermedia LPS from degrading IκB-α. Instead, azithromycin significantly diminished nuclear translocation and DNA binding activity of NF-κB p50 subunit induced with LPS. Azithromycin inhibited P. intermedia LPS-induced STAT1 and STAT3 phosphorylation. In addition, azithromycin up-regulated the mRNA level of SOCS1 in cells treated with LPS. In conclusion, azithromycin significantly attenuated P. intermedia LPS-induced production of IL-6 in murine macrophages via inhibition of NF-κB, STAT1 and STAT3 activation, which is possibly related to the activation of SOCS1 signaling. Further in vivo studies are required to better evaluate the potential of azithromycin in the treatment of periodontal disease., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Several reports have indicated that dietary intake of DHA is associated with lower prevalence of periodontitis. In the present study, we investigated the effect of DHA on the production of proinflammatory mediators in murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) isolated from Prevotella intermedia, a pathogen implicated in inflammatory periodontal disease, and its mechanisms of action. LPS was isolated from lyophilised P. intermedia ATCC 25,611 cells using the standard hot-phenol-water protocol. Culture supernatants were collected and assayed for NO, IL-1β and IL-6. Real-time PCR analysis was carried out to detect the expression of inducible NO synthase (iNOS), IL-1β, IL-6 and haeme oxygenase-1 (HO-1) mRNA. Immunoblot analysis was carried out to quantify the expression of iNOS and HO-1 protein and concentrations of signalling proteins. DNA-binding activities of NF-κB subunits were determined using an ELISA-based assay kit. DHA significantly attenuated the production of NO, IL-1β and IL-6 at both gene transcription and translation levels in P. intermedia LPS-activated RAW264.7 cells. DHA induced the expression of HO-1 in cells treated with P. intermedia LPS. Selective inhibition of HO-1 activity by tin protoporphyrin IX significantly mitigated the inhibitory effects of DHA on LPS-induced NO production. DHA significantly attenuated the phosphorylation of c-Jun N-terminal kinase induced by LPS. In addition, DHA suppressed the transcriptional activity of NF-κB by regulating the nuclear translocation and DNA-binding activity of NF-κB p50 subunit and inhibited the phosphorylation of signal transducer and activator of transcription 1. Further in vivo studies are needed to better evaluate the potential of DHA in humans as a therapeutic agent to treat periodontal disease.

Background: Nitric oxide (NO) could be a potential target for the development of new therapeutic approaches to the treatment of periodontal disease because this molecule plays a significant role in the tissue destruction observed in periodontitis. In this study, the authors investigate the effect of kaempferol on the production of NO by murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease, and try to determine the underlying mechanisms of action., Methods: NO production was assayed by measuring the accumulation of nitrite in culture supernatants. Real-time polymerase chain reaction was performed to quantify inducible NO synthase (iNOS) and heme oxygenase-1 (HO-1) mRNA expression. iNOS and HO-1 protein expression and phosphorylation of c-Jun N-terminal kinase and p38 were characterized via immunoblot analysis. Reactive oxygen species (ROS) production was measured using the redox-sensitive fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate., Results: Kaempferol significantly inhibited NO production and expression of iNOS protein in P. intermedia LPS-stimulated RAW246.7 cells without affecting iNOS mRNA expression. Kaempferol upregulated HO-1 expression in LPS-activated cells. Inhibition of HO-1 activity by tin protoporphyrin IX (SnPP) abolished the suppressive effect of kaempferol on NO production. In addition, kaempferol significantly attenuated P. intermedia LPS-induced increase of intracellular ROS, and SnPP blocked this reduction. Treatment with antioxidants downregulated the production of LPS-induced NO., Conclusions: Kaempferol inhibits NO production and iNOS protein expression in P. intermedia LPS-stimulated RAW264.7 cells at the translational level via HO-1-mediated ROS reduction and could be an efficient modulator of host response in the treatment of periodontal disease.

Background: Although a range of biologic and pharmacologic activities of luteolin has been reported, little is known about its potential as an agent to treat periodontal disease. In the present study, we investigated whether luteolin could downregulate the production of proinflammatory mediators in murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia (Pi), a major cause of inflammatory periodontal disease, and we attempted to elucidate the possible mechanisms of action., Methods: LPS was prepared from lyophilized Pi ATCC 25611 cells by the standard hot phenol-water method. Culture supernatants were collected and assayed for nitric oxide (NO) and interleukin (IL)-6. We used real-time polymerase chain reaction to detect inducible NO synthase (iNOS) and IL-6 mRNA expression. iNOS expression, phosphorylation of JNK and p38, IκB-α degradation, nuclear translocation of nuclear factor-kappaB (NF-κB) subunits, and signal transducer and activator of transcription-1 (STAT1) phosphorylation were characterized via immunoblotting. DNA-binding of NF-κB was also analyzed., Results: Luteolin strongly suppressed the production of NO and IL-6 at both gene transcription and translation levels in Pi LPS-activated RAW264.7 cells. Mitogen-activated protein kinase pathways were not involved in the inhibition of Pi LPS-induced NO and IL-6 release by luteolin. Luteolin did not reduce NF-κB transcriptional activity at the level of IκB-α degradation. Luteolin blocked NF-κB signaling through inhibition of nuclear translocation and DNA binding activity of NF-κB p50 subunit and suppressed STAT1 signaling., Conclusions: Although further research is encouraged to clarify the detailed mechanism of action, flavonoid luteolin may contribute to blockade of the host-destructive processes mediated by these two proinflammatory mediators and could have potential use in the treatment of inflammatory periodontal disease.

Although a range of biological and pharmacological activities of melatonin have been reported, little is known about its potential anti-inflammatory efficacy in periodontal disease. In this study, we investigated the effects of melatonin on the production of inflammatory mediators by murine macrophages stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a major cause of inflammatory reactions in the periodontium, and sought to determine the underlying mechanisms of action. Melatonin suppressed the production of nitric oxide (NO) and interleukin-6 (IL-6) at both gene transcription and translation levels in P. intermedia LPS-activated RAW264.7 cells. P. intermedia LPS-induced NF-κB-dependent luciferase activity was significantly inhibited by melatonin. Melatonin did not reduce NF-κB transcriptional activity at the level of IκB-α degradation. Melatonin blocked NF-κB signaling through the inhibition of nuclear translocation and DNA-binding activity of NF-κB p50 subunit and suppressed STAT1 signaling. Although further research is required to clarify the detailed mechanism of action, we conclude that melatonin may contribute to blockade of the host-destructive processes mediated by these two proinflammatory mediators and could be a highly efficient modulator of host response in the treatment of inflammatory periodontal disease., (© 2010 The Authors. Journal of Pineal Research © 2010 John Wiley & Sons A/S.)

The purpose of this study was to investigate the effects of lipopolysaccharide from Prevotella intermedia, a major cause of inflammatory periodontal disease, on the production of tumor necrosis factor (TNF)-alpha and the expression of TNF-alpha mRNA in differentiated THP-1 cells, a human monocytic cell line. The potential involvement of the three main mitogen-activated protein kinase (MAPK) signaling pathways in the induction of TNF-alpha production was also investigated. Lipopolysaccharide from P. intermedia ATCC 25611 was prepared by the standard hot phenol-water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. It was found that P. intermedia lipopolysaccharide can induce TNF-alpha mRNA expression and stimulate the release of TNF-alpha in differentiated THP-1 cells without additional stimuli. Treatment of the cells with P. intermedia lipopolysaccharide resulted in a simultaneous activation of three MAPKs [extracellular signal-related kinase 1/2 (ERK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2) and p38]. Pretreatment of the cells with MAPK inhibitors effectively suppressed P. intermedia lipopolysaccharide-induced TNF-alpha production without affecting the expression of TNF-alpha mRNA. These data thus provided good evidence that the MAPK signaling pathways are required for the regulation of P. intermedia lipopolysaccharide-induced TNF-alpha synthesis at the level of translation more than at the transcriptional level.

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.

Objectives: The purpose of this study was to examine the effects of lipopolysaccharide from Prevotella intermedia, a major cause of inflammatory periodontal disease, 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. intermedia lipopolysaccharide-induced NO production., Material and Methods: Lipopolysaccharide from P. intermedia ATCC 25611 was prepared by the standard hot phenol-water method. NO production was assayed by measuring the accumulation of nitrite in culture supernatants. Western blot analysis of iNOS and analysis of reverse transcription-polymerase chain reaction (RT-PCR) products were carried out., Results: We found that P. intermedia lipopolysaccharide can induce iNOS expression and stimulate the release of NO without additional stimuli and demonstrated an important role of the transcription factor nuclear factor-kappaB (NF-kappaB) and microtubule polymerization in NO production. The production of NO required l-arginine but not activation of protein kinase C or protein tyrosine kinase., Conclusions: The present study clearly shows that P. intermedia lipopolysaccharide fully induced iNOS expression and NO production in RAW264.7 cells in the absence of other stimuli. The ability of P. intermedia lipopolysaccharide to promote the production of NO may be important in the pathogenesis of inflammatory periodontal disease., ((c)Blackwell Munksgaard 2004)

BackgroundIn addition to immune cells, many other cell types are known to produce cytokines. Cultured normal mouse gallbladder epithelial cells, used as a model system for gallbladder epithelium, were examined for their ability to express the mRNA of various cytokines and chemokines in response to bacterial lipopolysaccharide. The synthesis and secretion of the tumor necrosis factor-alpha (TNF-alpha) protein by these cells was also measured.ResultsUntreated mouse gallbladder cells expressed mRNA for TNF-alpha, RANTES, and macrophage inflammatory protein-2 (MIP-2). Upon treatment with lipopolysaccharide, these cells now produced mRNA for Interleukin-1beta (IL-1beta), IL-6, monocyte chemoattractant protein-1 (MCP-1), and showed increased expression of TNF-alpha and MIP-2 mRNA. Untreated mouse gallbladder cells did not synthesize TNF-alpha protein; however, they did synthesize and secrete TNF-alpha upon treatment with lipopolysaccharide.MethodsCells were treated with lipopolysaccharides from 3 strains of bacteria. Qualitative and semi-quantitative RT-PCR, using cytokine or chemokine-specific primers, was used to measure mRNA levels of TNFalpha, IL-1beta, IL-6, IL-10, KC, RANTES, MCP-1, and MIP-2. TNF-alpha protein was measured by immunoassays.ConclusionThis research demonstrates that gallbladder epithelial cells in response to lipopolysaccharide exposure can alter their cytokine and chemokine RNA expression pattern and can synthesize and secrete TNFalpha protein. This suggests a mechanism whereby gallbladder epithelial cells in vivo may mediate gallbladder secretory function, inflammation and diseases in an autocrine/paracrine fashion by producing and secreting cytokines and/or chemokines during sepsis.

BackgroundIn addition to immune cells, many other cell types are known to produce cytokines. Cultured normal mouse gallbladder epithelial cells, used as a model system for gallbladder epithelium, were examined for their ability to express the mRNA of various cytokines and chemokines in response to bacterial lipopolysaccharide. The synthesis and secretion of the tumor necrosis factor-alpha (TNF-alpha) protein by these cells was also measured.ResultsUntreated mouse gallbladder cells expressed mRNA for TNF-alpha, RANTES, and macrophage inflammatory protein-2 (MIP-2). Upon treatment with lipopolysaccharide, these cells now produced mRNA for Interleukin-1beta (IL-1beta), IL-6, monocyte chemoattractant protein-1 (MCP-1), and showed increased expression of TNF-alpha and MIP-2 mRNA. Untreated mouse gallbladder cells did not synthesize TNF-alpha protein; however, they did synthesize and secrete TNF-alpha upon treatment with lipopolysaccharide.MethodsCells were treated with lipopolysaccharides from 3 strains of bacteria. Qualitative and semi-quantitative RT-PCR, using cytokine or chemokine-specific primers, was used to measure mRNA levels of TNFalpha, IL-1beta, IL-6, IL-10, KC, RANTES, MCP-1, and MIP-2. TNF-alpha protein was measured by immunoassays.ConclusionThis research demonstrates that gallbladder epithelial cells in response to lipopolysaccharide exposure can alter their cytokine and chemokine RNA expression pattern and can synthesize and secrete TNFalpha protein. This suggests a mechanism whereby gallbladder epithelial cells in vivo may mediate gallbladder secretory function, inflammation and diseases in an autocrine/paracrine fashion by producing and secreting cytokines and/or chemokines during sepsis.

Objective This study was performed in an attempt to examine the influence of agomelatine in mitigating the generation of proinflammatory mediators in RAW264.7 murine macrophages exposed to lipopolysaccharide (LPS) obtained from Prevotella intermedia , a gram-negative anaerobic bacterium that is related with various types of periodontal diseases, and the molecular mechanisms behind its effects. Design LPS from P. intermedia strain ATCC 25611 was prepared employing the conventional phenol-water procedure. Conditioned culture media were analyzed for the levels of nitric oxide (NO), interleukin-1β (IL-1β) and IL-6. Real-time PCR analysis was carried out to determine the mRNA levels of inducible NO synthase (iNOS), IL-1β, IL-6 and SOCS1. Protein expression levels were evaluated by immunoblot test. NF-κB-dependent SEAP reporter assay was performed using a reporter cell line. DNA-binding activities of NF-κB subunits were analyzed utilizing the ELISA-based kits. Results Agomelatine was found to down-regulate significantly the generation of iNOS-derived NO, IL-1β and IL-6 as well as the expression of their mRNAs in cells activated with P . intermedia LPS. Agomelatine decreased NF-κB-dependent SEAP release caused by P. intermedia LPS. Agomelatine did not inhibit NF-κB transcription induced by LPS at the level of IκB-α degradation. Instead, LPS-induced nuclear translocation and DNA binding of NF-κB p50 subunit was blocked by agomelatine. P . intermedia LPS-elicited activation of STAT1 and STAT3 was reduced notably by co-treatment with agomelatine. Agomelatine showed a tendency to enhance mRNA level of SOCS1 in LPS-activated cells as well. Conclusions Agomelatine merits further evaluation to reveal its usefulness on the host modulation of periodontal disease. [ABSTRACT FROM AUTHOR]