Examination of the signal transduction pathways leading to activation of gelatinolytic activity by interleukin-1alpha and Porphyromonas gingivalis in human osteosarcoma cells

Impact of Matrix Metalloproteinase-9 during Periodontitis and Cardiovascular Diseases

Matrix metalloproteinase-9 (MMP-9) has been shown to play a key role in endothelial function and perhaps pivotal in the correlation between periodontal disease and cardiovascular disease (CVD). For the study, the impact of MMP-9 of periodontitis and CVD on serum and saliva concentrations was analyzed. For the study patients with periodontitis (n = 31), CVD (n = 31), periodontitis + CVD (n = 31), and healthy patients (n = 31) were enrolled. Clinical and demographic characteristics as well as serum and salivary MMP-9 were evaluated. MMP-9 concentrations in serum and saliva were statistically elevated in patients with CVD (p < 0.01) and in patients with periodontitis plus CVD (p < 0.001) compared to patients with periodontitis and healthy subjects. Multivariate regression analysis showed that c-reactive protein (hs-CRP) was the only significant predictor for MMP-9 serum (p < 0.001), whereas hs-CRP (p < 0.001) and total cholesterol (p = 0.029) were the statistically significant salivary MMP-9 predictors. This study evidenced that patients with CVD and periodontitis + CVD presented elevated MMP-9 concentrations in serum and saliva compared to patients with periodontitis and healthy subjects. Furthermore, hs-CRP was a negative predictor of serum and salivary MMP-9.

Involvement of NLRP10 in IL-1α induction of oral epithelial cells by periodontal pathogens

This study investigated the pathogenesis of periodontitis and the role of nucleotide-binding oligomerization domain-like receptor protein 10 (NLRP10). The human oral epithelial cell line HOK-16B was infected with two periodontal pathogens, Tannerella forsythia and Fusobacterium nucleatum, at various MOIs. RT-PCR and immunoblotting demonstrated that infection increased mRNA and protein expression of NLRP10, respectively. The siRNA-mediated NLRP10 knockdown significantly reduced IL-1α expression and secretion. Both bacteria induced phosphorylation of ERK, JNK and p38 MAP kinases in HOK-16B cells. NLRP10 knockdown impaired ERK phosphorylation only. ERK inhibition significantly decreased the expression of T. forsythia- and F. nucleatum-induced IL-1α. Our data suggest that NLRP10 is involved in activating the ERK signalling pathway in HOK-16B cells infected with T. forsythia and F. nucleatum. This pathway likely augments the pro-inflammatory cytokine IL-1α levels, which may play a critical role in periodontitis.

Inhibitory activities of selected Sudanese medicinal plants on Porphyromonas gingivalis and matrix metalloproteinase-9 and isolation of bioactive compounds from Combretum hartmannianum (Schweinf) bark

Background

Periodontal diseases are one of the major health problems and among the most important preventable global infectious diseases. Porphyromonas gingivalis is an anaerobic Gram-negative bacterium which has been strongly implicated in the etiology of periodontitis. Additionally, matrix metalloproteinases-9 (MMP-9) is an important factor contributing to periodontal tissue destruction by a variety of mechanisms. The purpose of this study was to evaluate the selected Sudanese medicinal plants against P. gingivalis bacteria and their inhibitory activities on MMP-9.

Methods

Sixty two methanolic and 50% ethanolic extracts from 24 plants species were tested for antibacterial activity against P. gingivalis using microplate dilution assay method to determine the minimum inhibitory concentration (MIC). The inhibitory activity of seven methanol extracts selected from the 62 extracts against MMP-9 was determined by Colorimetric Drug Discovery Kit. In search of bioactive lead compounds, Combretum hartmannianum bark which was found to be within the most active plant extracts was subjected to various chromatographic (medium pressure liquid chromatography, column chromatography on a Sephadex LH-20, preparative high performance liquid chromatography) and spectroscopic methods (liquid chromatography-mass spectrometry, Nuclear Magnetic Resonance (NMR)) to isolate and characterize flavogalonic acid dilactone and terchebulin as bioactive compounds.

Results

About 80% of the crude extracts provided a MIC value ≤4 mg/ml against bacteria. The extracts which revealed the highest potency were: methanolic extracts of Terminalia laxiflora (wood; MIC = 0.25 mg/ml) followed by Acacia totrtilis (bark), Ambrosia maritima (aerial part), Argemone mexicana (seed), C. hartmannianum (bark), Terminalia brownii (wood) and 50% ethanolic extract of T. brownii (bark) with MIC values of 0.5 mg/ml. T. laxiflora (wood) and C. hartmannianum (bark) which belong to combretaceae family showed an inhibitory activity over 50% at the concentration of 10 μg/ml against MMP-9. Additionally, MMP-9 was significantly inhibited by terchebulin with IC₅₀ value of 6.7 μM.

Conclusions

To the best of our knowledge, flavogalonic acid dilactone and terchebulin were isolated from C. hartmannianium bark for the first time in this study. Because of terchebulin and some crude extracts acting on P. gingivalis bacteria and MMP-9 enzyme that would make them promising natural preference for preventing and treating periodontal diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1735-y) contains supplementary material, which is available to authorized users.

Role of mitogen-activated protein kinase in osteoblast differentiation

Local control of osteoblast differentiation and bone formation is not well understood. We have previously seen biphasic effects on cell differentiation in response to the short- and long-term exposure to IL-1β in rat calvarial osteoblasts. To characterize the signaling pathway mechanisms regulating IL-1β biphasic effects, we examined the contribution of mitogen-activated protein kinase (MAPK) family. Cells were pretreated with specific inhibitors to extracellular signal-regulated kinase (ERK, PD98059), p38 (SB203580), and c-JUN N-terminal kinase (JNK, SP600125), then co-cultured with IL-1β for 2, 4, and 6 days. Cell differentiation was determined by measuring bone nodules after 10 days of culture. These inhibitors did not alter biphasic effects of IL-1β on cell differentiation. However, PD98059 and U2016, another inhibitor of ERK activation robustly increased osteoblast differentiation compared to vehicle-treated control in a time- and dose-dependent manner. PD98059 appears to stimulate alkaline phosphatase (ALP) activity to promote cell differentiation, where IL-1β appears to suppress it. Interestingly, continuous ERK inhibition with PD98059, after 2 and 4 days of IL-1β treatment, enhanced the IL-1β anabolic effect by increasing bone nodules formed. These observations provide a potential mechanism involving ERK pathway in osteoblasts differentiation and suggest that MAPK family may not directly regulate IL-1β biphasic effects.

Inhibitory effect of panduratin A on c-Jun N-terminal kinase and activator protein-1 signaling involved in Porphyromonas gingivalis supernatant-stimulated matrix metalloproteinase-9 expression in human oral epidermoid cells

Porphyromonas gingivalis, a type of Gram-negative periodontopathogen, causes periodontal disease by activating intracellular signaling pathways that produce excessive inflammatory responses such as matrix metalloproteinases (MMPs). Recently, we reported that panduratin A, a chalcone compound isolated from Kaempferia pandurata ROXB., caused the decreased levels of MMP-9 secretion, protein, and gene expression in human oral epidermoid KB cells exposed to P. gingivalis supernatant. In this study, we clarified if mitogen-activated protein kinase (MAPK) signaling mediated MMP-9 expression by examining the effect of specific MAPK inhibitors, i.e. U0126, SB203580, and SP600125, on P. gingivalis supernatant-stimulated MMP-9 expression in KB cells. We next elucidated the molecular mechanism by which panduratin A attenuated signaling pathways involved in MMP-9 expression by performing gelatin zymography, Western blotting, reverse transcription-polymerase chain reaction, and promoter assays. Exposure of KB cells to P. gingivalis supernatant up-regulated the expression of MMP-9 protein and gene, and activation of activator protein-1 (AP-1) element, MAPK phosphorylation (extracellular signal-related kinase 1/2 (ERK1/2), p38, and c-Jun N-terminal kinase (JNK)), and transcription factors (Elk1, c-Jun, and c-Fos). A JNK inhibitor (SP600125) significantly attenuated MMP-9 gene expression and AP-1 activity in KB cells in response to P. gingivalis supernatant. Similar to SP600125, panduratin A was found to strongly suppress the level of phosphorylated JNK and block AP-1 activity in P. gingivalis supernatant-stimulated KB cells. In summary, JNK and AP-1 are the major signaling for P. gingivalis supernatant-stimulated MMP-9 expression in KB cells, and panduratin A markedly down-regulates MMP-9 expression through inhibition of these signaling.

Kaempferia pandurata Roxb. inhibits Porphyromonas gingivalis supernatant-induced matrix metalloproteinase-9 expression via signal transduction in human oral epidermoid cells

ETHNOPHARMACOLOGICAL RELEVANCE

Kaempferia pandurata Roxb., an edible tropical medicinal plant (Zingiberaceae), has been traditionally used to treat dental caries. However, its efficacy on inhibition of matrix metalloproteinase (MMP)-9 for preventing periodontal inflammation has been rarely studied to date.

AIM OF THE STUDY

This present study was focused to investigate the effects of the ethanolic extract of Kaempferia pandurata Roxb. on inhibition of Porphyromonas gingivalis supernatant-induced MMP-9 expression through activation of mitogen-activated protein kinase (MAPK) signaling pathways in human oral epidermoid KB cells.

MATERIALS AND METHODS

MMP-9 expression and its signaling pathways in KB cells induced by Porphyromonas gingivalis supernatant were determined by gelatin zymogram, Western blotting and reporter gene assays.

RESULTS

Kaempferia pandurata significantly decreased MMP-9 expression at both protein and mRNA levels in a dose-dependent manner. Kaempferia pandurata interfered Porphyromonas gingivalis supernatant-induced MMP-9 expression in KB cells by downregulating MAPK phosphorylation (extracellular signal-related kinase 1/2, p38 kinase and c-Jun N-terminal kinase), inhibiting transcriptional expression (Elk1, c-Jun and c-Fos), and blocking AP-1 and NF-kappaB activities.

CONCLUSIONS

Kaempferia pandurata could be employed as a candidate for MMP-9 inhibitor with therapeutic potential for treatment of periodontal inflammation.

Regulation of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases by Porphyromonas gingivalis in an engineered human oral mucosa model

Under physiological conditions, matrix metalloproteinases (MMPs) are involved in the remodeling and turnover of periodontal tissue and their activity is tightly regulated by tissue inhibitors of metalloproteinases (TIMPs). Disturbances in the balance between MMPs and TIMPs may result in excessive tissue destruction. We previously used an engineered human oral mucosa (EHOM) model to demonstrate that Porphyromonas gingivalis, a major etiological agent of periodontitis, infiltrates connective tissue and induces significant loss of attachment of the stratified epithelium from the basement membrane. The aim of the present study was to investigate the effect of P. gingivalis on the expression and production of MMP-2, MMP-9, TIMP-1, and TIMP-2 by oral fibroblasts and epithelial cells. The EHOM model was infected with P. gingivalis ATCC 33277 or its derivative gingipain-null mutant (KDP128) for different periods of time. MMP and TIMP mRNA expression was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) analysis, while protein secretion into the culture medium was assessed by enzyme-linked immunosorbent assays. P. gingivalis significantly up-regulated MMP-2 and MMP-9 mRNA expression by oral epithelial cells. This MMP gene activation was paralleled by TIMP-2 gene activation. However, only MMP-9 mRNA expression was significantly enhanced by the gingipain-null mutant. At 8 and 24 h post-infection, P. gingivalis increased significantly the MMP-9 protein level compared to the uninfected EHOM model. The present study reports the ability of P. gingivalis to regulate MMP and TIMP production by oral cells, a phenomenon that may contribute to tissue destruction.

Signal transduction pathways involved in the stimulation of tissue type plasminogen activator by interleukin-1alpha and Porphyromonas gingivalis in human osteosarcoma cells

BACKGROUND

Recently, evidences have shown that tissue type plasminogen activator (t-PA) may play an important role in the pathogenesis of periodontal diseases. However, the mechanisms and signal transduction pathways involved in the production of t-PA in human osteosarcoma cells are not fully understood.

OBJECTIVES

The purpose of this study was to investigate the caseinolytic activity in human osteosarcoma cell line U2OS cells stimulated with interleukin-1alpha (IL-1alpha) or Porphyromonas gingivalis in the absence or presence of p38 inhibitor SB203580, mitogen-activated protein kinase kinase (MEK) inhibitor U0126, and phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002.

METHODS

IL-1alpha and the supernatants of P. gingivalis were used to evaluate the caseinolytic activity in U2OS cells by using casein zymography and enzyme-linked immunosorbent assay (ELISA). Furthermore, to search possible signal transduction pathways, SB203580, U0126, and LY294002 were added to test how they modulated the caseinolytic activity.

RESULTS

Casein zymography exhibited a caseinolytic band with a molecular weight of approximately 70 kDa, suggestive of the presence of t-PA. Secretion of t-PA was found to be stimulated with IL-1alpha and P. gingivalis during a 2-day culture period (p < 0.05). From the results of casein zymography and ELISA, SB203580, U0126, and LY294002 significantly reduced the IL-1alpha or P. gingivalis-stimulated t-PA production, respectively (p < 0.05).

CONCLUSIONS

Our findings demonstrated that IL-1alpha and P. gingivalis enhance t-PA production in human osteosarcoma cells, and that the signal transduction pathways p38, MEK, and PI3K are involved in the inhibition of t-PA. SB203580, U0126, and LY294002 suppress t-PA production and/or activity and may therefore be valuable therapeutics in t-PA-mediated periodontal destruction, and might be proved clinically useful agents, in combination with standard treatment modalities, in the treatment of periodontitis.