Alpha-mangostin suppresses IL-6 and IL-8 expression in P. gingivalis LPS-stimulated human gingival fibroblasts

P. gingivalis-Induced TLR2 Interactome Analysis Reveals Association with PARP9

Porphyromonas gingivalis is a Gram-negative anaerobic bacterium strongly associated with periodontal disease. Toll-like receptor 2 (TLR2) is indispensable for the host response to P. gingivalis, but P. gingivalis escapes from immune clearance via TLR2-dependent activation of phosphoinositide-3-kinase (PI3K). To probe the TLR2-dependent escape pathway of P. gingivalis, we analyzed the TLR2 interactome induced following P. gingivalis infection or activation by a synthetic lipopeptide TLR2/1 agonist on human macrophages overexpressing TLR2. Interacting proteins were stabilized by cross-linking and then immunoprecipitated and analyzed by mass spectrometry. In total, 792 proteins were recovered and network analysis enabled mapping of the TLR2 interactome at baseline and in response to infection. The P. gingivalis infection-induced TLR2 interactome included the poly (ADP-ribose) polymerase family member mono-ADP-ribosyltransferase protein 9 (PARP9) and additional members of the PARP9 complex (DTX3L and NMI). PARP9 and its complex members are highly upregulated in macrophages exposed to P. gingivalis or to the synthetic TLR2/1 ligand Pam3Cys-Ser-(Lys)4 (PAM). Consistent with its known role in virally induced interferon production, PARP9 knockdown blocked type I interferon (IFN-I) production in response to P. gingivalis and reduced inflammatory cytokine production. We found that P. gingivalis drives signal transducer and activation of transcription (STAT) 1 (S727) phosphorylation through TLR2-PARP9, explaining PARP9's role in the induction of IFN-I downstream of TLR2. Furthermore, PARP9 knockdown reduced PI3K activation by P. gingivalis, leading to improved macrophage bactericidal activity. In summary, PARP9 is a novel TLR2 interacting partner that enables IFN-I induction and P. gingivalis immune escape in macrophages downstream of TLR2 sensing.

Biochemical features and therapeutic potential of α-Mangostin: Mechanism of action, medicinal values, and health benefits

α-Mangostin (α-MG) is a natural xanthone obtained from the pericarps of mangosteen. It exhibits excellent potential, including anti-cancer, neuroprotective, antimicrobial, antioxidant, and anti-inflammatory properties, and induces apoptosis. α-MG controls cell proliferation by modulating signaling molecules, thus implicated in cancer therapy. It possesses incredible pharmacological features and modulates crucial cellular and molecular factors. Due to its lesser water solubility and pitiable target selectivity, α-MG has limited clinical application. As a known antioxidant, α-MG has gained significant attention from the scientific community, increasing interest in extensive technical and biomedical applications. Nanoparticle-based drug delivery systems were designed to improve the pharmacological features and efficiency of α-MG. This review is focused on recent developments on the therapeutic potential of α-MG in managing cancer and neurological diseases, with a special focus on its mechanism of action. In addition, we highlighted biochemical and pharmacological features, metabolism, functions, anti-inflammatory, antioxidant effects and pre-clinical applications of α-MG.

α-Mangostin Inhibits the Activation of Myofibroblasts via Downregulation of Linc-ROR-Mediated TGFB1/Smad Signaling

Oral submucous fibrosis (OSF) is a premalignant disorder and persistent activation of myofibroblasts is implicated in this pathological progression. Increasing attention has been addressed towards non-coding RNA-regulated myofibroblasts activities and the effects of phytochemicals on non-coding RNA modulation are of great importance. In the present study, we examined the anti-fibrosis property of α-mangostin, a xanthone isolated from the pericarp of mangosteen. We found that α-mangostin exhibited inhibitory potency in myofibroblast activities and expression of fibrosis markers at the concentrations that caused neglectable damage to normal cells. Apart from the downregulation of TGF-β1/Smad2 signaling, we found that α-mangostin attenuated the expression of long non-coding RNA LincROR as well. Our results demonstrated that the effects of α-mangostin on myofibroblast activation were reverted when LincROR was overexpressed. Additionally, we showed the expression of LincROR in OSF specimens was elevated and silencing of LincROR successfully attenuated myofibroblast characteristics and TGF-β1/Smad2 activation. Taken together, these findings indicated that the anti-fibrosis effects of α-mangostin merit consideration and may be due to the attenuation of LincROR.

Dexamethasone-loaded zeolitic imidazolate frameworks nanocomposite hydrogel with antibacterial and anti-inflammatory effects for periodontitis treatment

Periodontitis is a bacterial-induced, chronic inflammatory disease characterized by progressive destruction of tooth-supporting structures. Pathogenic bacteria residing in deep periodontal pockets after traditional manual debridement can still lead to local inflammatory microenvironment, which remains a challenging problem and an urgent need for better therapeutic strategies. Here, we integrated the advantages of metal-organic frameworks (MOFs) and hydrogels to prepare an injectable nanocomposite hydrogel by incorporating dexamethasone-loaded zeolitic imidazolate frameworks-8 (DZIF) nanoparticles into the photocrosslinking matrix of methacrylic polyphosphoester (PPEMA) and methacrylic gelatin (GelMA). The injectable hydrogel could be easily injected into deep periodontal pockets, achieving high local concentrations without leading to antibiotic resistance. The nanocomposite hydrogel had high antibacterial activity and constructs with stable microenvironments maintain cell viability, proliferation, spreading, as well as osteogenesis, and down-regulated inflammatory genes expression in vitro. When evaluated on an experimental periodontitis rat model, micro-computed tomography and histological analyses showed that the nanocomposite hydrogel effectively reduced periodontal inflammation and attenuated inflammation-induced bone loss in a rat model of periodontitis. These findings suggest that the nanocomposite hydrogel might be a promising therapeutic candidate for treating periodontal disease.

ALPHA-MANGOSTIN (Garcinia mangostana Linn.) AND ITS POTENTIAL APPLICATION IN MITIGATING CHRONIC WOUND HEALING

Wound healing is a complex and dynamic cellular process to restore tissue function. Current treatments for chronic wounds especially diabetic ulcers are expensive, with adverse effects. Recently, numerous researchers have focused on the potential effect of natural products on wound healing. One of them is mangosteen (Garcinia mangostana Linn). It is a well-known tropical fruit that is native to Southeast Asia. The active ingredient of mangosteen pericarp contains xanthones that exhibit a wide range of pharmacological activities, including anti-inflammatory and anti-bacterial properties which are the core elements needed in wound healing. Firstly, this review discusses the concepts of abnormal and normal wound healing mechanisms. Then an in depth observation of the pharmacological activities of mangosteen and its derivatives was presented to study their potentially beneficial applications in the treatment of chronic wound healing which is a contemporary medical issue.

Periodontal Pathogens and Neuropsychiatric Health

Increasing evidence incriminates low-grade inflammation in cardiovascular, metabolic diseases, and neuropsychiatric clinical conditions, all important causes of morbidity and mortality. One of the upstream and modifiable precipitants and perpetrators of inflammation is chronic periodontitis, a polymicrobial infection with Porphyromonas gingivalis (P. gingivalis) playing a central role in the disease pathogenesis. We review the association between P. gingivalis and cardiovascular, metabolic, and neuropsychiatric illness, and the molecular mechanisms potentially implicated in immune upregulation as well as downregulation induced by the pathogen. In addition to inflammation, translocation of the pathogens to the coronary and peripheral arteries, including brain vasculature, and gut and liver vasculature has important pathophysiological consequences. Distant effects via translocation rely on virulence factors of P. gingivalis such as gingipains, on its synergistic interactions with other pathogens, and on its capability to manipulate the immune system via several mechanisms, including its capacity to induce production of immune-downregulating micro-RNAs. Possible targets for intervention and drug development to manage distal consequences of infection with P. gingivalis are also reviewed.

A review on α-mangostin as a potential multi-target-directed ligand for Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by progressive memory loss, declining language skills and other cognitive disorders. AD has brought great mental and economic burden to patients, families and society. However due to the complexity of AD's pathology, drugs developed for the treatment of AD often fail in clinical or experimental trials. The main problems of current anti-AD drugs are low efficacy due to mono-target method or side effects, especially high hepatotoxicity. To tackle these two main problems, multi-target-directed ligand (MTDL) based on "one molecule, multiple targets" has been studied. MTDLs can regulate multiple biological targets at the same time, so it has shown higher efficacy, better safety. As a natural active small molecule, α-mangostin (α-M) has shown potential multi-factor anti-AD activities in a series of studies, furthermore it also has a certain hepatoprotective effect. The good availability of α-M also provides support for its application in clinical research. In this work, multiple activities of α-M related to AD therapy were reviewed, which included anti-cholinesterase, anti-amyloid-cascade, anti-inflammation, anti-oxidative stress, low toxicity, hepatoprotective effects and drug formulation. It shows that α-M is a promising candidate for the treatment of AD.

Studies on Haloperidol and Adjunctive α-Mangostin or Raw Garcinia mangostana Linn Pericarp on Bio-Behavioral Markers in an Immune-Inflammatory Model of Schizophrenia in Male Rats

Schizophrenia is a severe brain disorder that is associated with neurodevelopmental insults, such as prenatal inflammation, that introduce redox-immune-inflammatory alterations and risk for psychotic symptoms later in life. Nutraceuticals may offer useful adjunctive benefits. The aim of this study was to examine the therapeutic effects of Garcinia mangostana Linn (GML) and one of its active constituents, α-mangostin (AM), alone and as adjunctive treatment with haloperidol (HAL) on schizophrenia related bio-behavioral alterations in a maternal immune-activation (MIA) model. Sprague-Dawley dams were exposed to lipopolysaccharide (LPS) (n = 18) or vehicle (n = 3) on gestational days 15 and 16. Male offspring (n = 72) were treated from PND 52-66 with either vehicle, HAL (2 mg/kg), GML (50 mg/kg), HAL + GML, AM (20 mg/kg), or HAL + AM. Control dams and control offspring were treated with vehicle. In order to cover the mood-psychosis continuum, prepulse inhibition (PPI) of startle, open field test (locomotor activity), and the forced swim test (depressive-like behavior) were assessed on PND's 64-65, followed by assay of frontal-cortical lipid peroxidation and plasma pro-inflammatory cytokines, viz. interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α). MIA-induced deficits in sensorimotor gating were reversed by HAL and HAL + GML, but not GML and AM alone. MIA-induced depressive-like behavior was reversed by AM and GML alone and both in combination with HAL, with the combinations more effective than HAL. MIA-induced cortical lipid peroxidation was reversed by HAL and AM, with elevated IL-6 levels restored by GML, AM, HAL, and HAL + GML. Elevated TNF-α was only reversed by GML and HAL + GML. Concluding, prenatal LPS-induced psychotic- and depressive-like bio-behavioral alterations in offspring are variably responsive to HAL, GML, and AM, with depressive (but not psychosis-like) manifestations responding to GML, AM, and combinations with HAL. AM may be a more effective antioxidant than GML in vivo, although this does not imply an improved therapeutic response, for which trials are required.

Identification of Interleukin-8-Reducing Lead Compounds Based on SAR Studies on Dihydrochalcone-Related Compounds in Human Gingival Fibroblasts (HGF-1 cells) In Vitro

Background: In order to identify potential activities against periodontal diseases, eighteen dihydrochalcones and structurally related compounds were tested in an established biological in vitro cell model of periodontal inflammation using human gingival fibroblasts (HGF-1 cells). Methods: Subsequently to co-incubation of HGF-1 cells with a bacterial endotoxin (Porphyromonas gingivalis lipopolysaccharide, pgLPS) and each individual dihydrochalcone in a concentration range of 1 µM to 100 µM, gene expression of interleukin-8 (IL-8) was determined by qPCR and cellular interleukin-8 (IL-8) release by ELISA. Results: Structure–activity analysis based on the dihydrochalcone backbone and various substitution patterns at its aromatic ring revealed moieties 2′,4,4′,6′-tetrahydroxy 3-methoxydihydrochalcone (7) to be the most effective anti-inflammatory compound, reducing the pgLPS-induced IL-8 release concentration between 1 µM and 100 µM up to 94%. In general, a 2,4,6-trihydroxy substitution at the A-ring and concomitant vanilloyl (4-hydroxy-3-methoxy) pattern at the B-ring revealed to be preferable for IL-8 release inhibition. Furthermore, the introduction of an electronegative atom in the A,B-linker chain led to an increased anti-inflammatory activity, shown by the potency of 4-hydroxybenzoic acid N-vanillylamide (13). Conclusions: Our data may be feasible to be used for further lead structure designs for the development of potent anti-inflammatory additives in oral care products.

Effect of Photobiomodulation on Secretion of IL-6 and IL-8 by Human Gingival Fibroblasts In Vitro

Objective: The aim of this study was to evaluate the effects of 940-nm diode laser irradiation on proinflammatory cytokine secretions [interleukin (IL)-6 and IL-8] by human gingival fibroblasts in vitro. Background: Photobiomodulation has been routinely used in many dental procedures; however, the exact biological action mechanism of photobiomodulation and its therapeutic benefits have not been established. Methods: Cells derived from systemically healthy individuals were treated with three different laser parameters-6 J for 20 sec [0.84 J/cm² (0.04 W/cm²)], 10 J for 20 sec [1.4 J/cm² (0.07 W/cm²)], and 14 J for 20 sec [1.97 J/cm² (0.09 W/cm²)]-in the presence and absence of 1 μg/mL lipopolysaccharide (LPS) stimulation. Laser irradiations were carried out by a 940-nm diode laser device in continuous pain therapy mode with a deep tissue handpiece. Changes in cell viability, cytokine secretions, and mitogen-activated protein kinase pathway expressions were investigated, and results were compared with negative (medium) and positive control (1 μg/mL LPS) groups. The data obtained were statistically analyzed by the Mann-Whitney U test for pairwise comparisons among groups at the 0.05 level of significance. Results: Laser therapy with 0.84-1.4 J/cm² amplified IL-6 and IL-8 secretions, whereas 1.97 J/cm² suppressed IL-6 and IL-8 release in LPS-stimulated cells. Cell viability did not show a variation with photobiomodulation. Conclusions: These results demonstrate that photobiomodulation can alter IL-6 and IL-8 release, with cytokine suppression potency at a relatively high dose, as demonstrated previously. However, in contrast, we found that a low level of stimulation (6 J) in the presence of inflammation (LPS stimulation) may further enhance IL-6 and IL-8 release. We also found that p38 and ERK1/2 pathways are activated by LPS as well as by photobiomodulation.

Anti-inflammatory and in vitro bone formation effects of Garcinia mangostana L. and propolis extracts

The purpose of this study was to determine the anti-inflammatory and in vitro bone formation effects of Garcinia mangostana L. (mangosteen) and propolis extracts. Immortalized human gingival fibroblasts (hTERT-hNOF) cells were treated with Porphyromonas gingivalis KCOM 2804 lipopolysaccharide followed by treatment with mangosteen and propolis extract alone or in combination. Expression levels of inflammatory cytokines were evaluated by enzyme-linked immunosorbent assay. Effect of mangosteen and/or propolis extracts on mineralization of MG-63 cells was evaluated by alkaline phosphatase activity and alizarin red S staining. Group mangosteen extract complex 1:34 (1 µg/ml mangosteen extract and 34 µg/ml propolis extract) significantly reduced expression levels of IL-6, IL-8, and PGE₂. It had higher than other groups in vitro bone formation effect on MG63 cells. These results suggest that mangosteen and propolis extract complex could be used in the prevention and treatment of periodontal disease.

Porphyromonas gingivalis induced inflammatory responses and promoted apoptosis in lung epithelial cells infected with H1N1 via the Bcl‑2/Bax/Caspase‑3 signaling pathway

The aim of the present study was to investigate the effects of Porphyromonas gingivalis (P. gingivalis) on inflammatory cytokine and nitic oxide (NO) production in lung epithelial cells infected with H1N1, and the underlying mechanisms. Lung epithelial cells were co-infected with P. gingivalis and H1N1. The concentrations of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 were detected via an ELISA, and the concentration of NO was detected by the nitrate reductive enzymatic method at 4, 8, 12 and 24 h following infection. The expression levels of inducible NO synthase (iNOS) was detected by western blotting. The apoptotic rate of lung epithelial cells was detected by flow cytometry. The relative protein expression levels of B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax) and caspase-3 in lung epithelial cells were detected by western blotting. Compared with the control group, the concentration of the inflammatory cytokines TNF-α, IL-1β and IL-6 exhibited a significant increase (P<0.05) in the viral-infected, bacterial-infected and co-infected groups. The concentration of NO also increased significantly (P<0.05), along with the rise in the expression levels of iNOS (P<0.05) and the increase in the apoptosis rate of lung epithelial cells (P<0.05). The relative expression levels of caspase-3 and Bax proteins were increased significantly in the viral- and bacterial-infected groups when compared with the control. The relative expression levels of Bcl-2 protein exhibited a significant decrease in lung epithelial cells following the co-infection with P. gingivalis and H1N1 compared with the control (P<0.05). The results of the present study revealed that the combination of P. gingivalis and H1N1 infection in lung epithelial cells may promote the production of inflammatory cytokines and increase NO production, leading to increased levels of apoptosis in lung epithelial cells via the Bcl-2/Bax/caspase-3 signaling pathway.

Antibacterial and Anti-inflammatory Potential of Morus alba Stem Extract

Background:

Periodontitis, a chronic inflammatory disease, is the leading cause of tooth loss in adults. Evidence for the anti inflammatory activity of M. alba Stem Extract (MSE) in periodontal disease is limited.

Objective:

The study aimed to investigate the inhibitory effect of MSE on the growth of periodontopathic bacteria and expression of interleukin (IL)-6 and IL-8 in Porphyromonas gingivalis Lipopolysaccharide (LPS)-stimulated human Periodontal Ligament (hPDL) fibroblasts.

Methods:

The antimicrobial activities of MSE were tested against P. gingivalis and Aggregatibacter actinomycetemcomitans by the disk diffusion, the minimum inhibitory concentration and the minimal bactericidal concentration methods. Cytotoxicity of P. gingivalis LPS and MSE on hPDL fibroblasts was determined by MTS assay. The expression of cytokines (IL-6 and IL-8) mRNA and proteins in hPDL fibroblasts was measured using the reverse transcription-qPCR and enzyme-linked immunosorbent assay, respectively.

Results:

MSE exhibited antibacterial activities against P. gingivalis and A. actinomycetemcomitans with the zones of inhibition of 10.00 ± 0.33 mm and 17.33 ± 0.58 mm, respectively. MIC and MBC values for MSE against P. gingivalis were 62.5 μg/ml. The MIC and MBC values against A. actinomycetemcomitans were 250 μg/mL and 500 μg/ml, respectively. P. gingivalis LPS was shown to mediate the expression of pro-inflammatory cytokines in hPDL fibroblasts. However, treatment with MSE concentrations of 2.5 and 5.0 μg/ml significantly suppressed P. gingivalis LPS-induced IL-6 and IL-8 mRNA and protein expression (p< 0.05).

Conclusion:

The present study demonstrates that MSE has antibacterial activity against two putative periodontal pathogens. MSE suppressed IL-6 and IL-8 expression in P. gingivalis LPS-stimulated hPDL fibroblasts, indicating a possible anti-inflammatory effect. Thus, it is a potential adjunctive agent for the treatment of periodontitis.

An anti-inflammatory molecular mechanism of action of α-mangostin, the major xanthone from the pericarp of Garcinia mangostana: an in silico, in vitro and in vivo approach

α-Mangostin (αMN) is a xanthone present in the pericarp of Garcinia mangostana Linn.

Metformin Inhibits Porphyromonas gingivalis Lipopolysaccharide-Influenced Inflammatory Response in Human Gingival Fibroblasts via Regulating Activating Transcription Factor-3 Expression

BACKGROUND

Chronic periodontitis, one of the most prevalent oral diseases, is associated with Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) infection and has profound effects on type 2 diabetes mellitus (t2DM). Metformin, a well-known antidiabetic agent, has been reported to exert anti-inflammatory effects on various cells. This study aims to investigate the role of metformin on LPS-influenced inflammatory response in human gingival fibroblasts (HGFs).

METHODS

Dose-dependent additive effects of metformin on LPS-influenced HGFs were detected. Cell-counting assay was used to determine effects of metformin and LPS on viability of HGFs. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction (qRT-PCR) were applied to detect levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in differently treated cells. Activating transcription factor-3 (ATF3) small interfering (si)RNA transfection was used to determine the mechanism of metformin action, and the transfection efficiency was observed by fluorescence microscope. Effects of ATF3 knockdown were determined by qRT-PCR and Western blot.

RESULTS

Results showed that 5 μg/mL Pg LPS and 0.1, 0.5, and 1 mM metformin exhibited no toxicity to HGFs, and metformin inhibited LPS-influenced IL-1β, IL-6, and TNF-α production in a dose-dependent manner. Metformin and LPS could synergistically facilitate ATF3 expression, and ATF3 knockdown abolished inhibitory effects of metformin on LPS-influenced inflammatory cytokine production in HGFs.

CONCLUSION

The present study confirms that metformin suppresses LPS-enhanced IL-6, IL-1β, and TNF-α production in HGFs via increasing ATF3 expression.

Inhibitory effect of alpha-mangostin on Candida biofilms

The objective of this study was to determine the inhibitory effect of alpha-mangostin on Candida biofilms. Candida species including Candida albicans, Candida krusei, Candida tropicalis, and Candida glabrata were tested. Candida biofilms were formed in flat-bottomed 96-well microtiter plates. The metabolic activity of cells within biofilms was quantified using the XTT assay. The results demonstrated that alpha-mangostin showed a significant anti-biofilm effect on both developing biofilms and preformed biofilms of Candida species. It may be concluded that alpha-mangostin could be an anti-biofilm agent against Candida species. Further in vivo investigations are needed to uncover the therapeutic values of this medicinal plant.

Porphyromonas gingivalis: An Overview of Periodontopathic Pathogen below the Gum Line

Periodontal disease represents a group of oral inflammatory infections initiated by oral pathogens which exist as a complex biofilms on the tooth surface and cause destruction to tooth supporting tissues. The severity of this disease ranges from mild and reversible inflammation of the gingiva (gingivitis) to chronic destruction of connective tissues, the formation of periodontal pocket and ultimately result in loss of teeth. While human subgingival plaque harbors more than 500 bacterial species, considerable research has shown that Porphyromonas gingivalis, a Gram-negative anaerobic bacterium, is the major etiologic agent which contributes to chronic periodontitis. This black-pigmented bacterium produces a myriad of virulence factors that cause destruction to periodontal tissues either directly or indirectly by modulating the host inflammatory response. Here, this review provides an overview of P. gingivalis and how its virulence factors contribute to the pathogenesis with other microbiome consortium in oral cavity.