Inhibitory effect of Acer tegmentosum maxim extracts on P. gingivalis LPS-induced periodontitis

Application of lipopolysaccharide in establishing inflammatory models

Lipopolysaccharide (LPS), a unique component of the outer membrane of Gram-negative bacteria, possesses immune-activating properties. It induces an immune response by stimulating host cells to produce a lot of inflammatory cytokines with a thermogenic effect, which may cause an inflammatory response. In the past few decades, the structure and function of LPS and its mechanism leading to inflammation have been extensively analyzed. Since LPS can cause inflammation, it is often used to establish inflammation models. These models are crucial in the study of inflammatory diseases that pose a serious threat to human health. In addition, the non-pro-inflammatory effects of LPS under certain circumstances are also being studied widely. This review summarizes the methods by which LPS has been used to establish inflammatory models at the cellular and animal levels to study related diseases. It also introduces in detail the evaluation indicators necessary for the successful establishment of these models, providing a reference for future research.

MicroRNA-671-5p regulates the inflammatory response of periodontal ligament stem cells via the DUSP8/p38 MAPK pathway

BACKGROUND

MicroRNAs are differentially expressed in periodontitis tissues. They are involved in cellular responses to inflammation and can be used as markers for diagnosing periodontitis. Microarray analysis showed that the expression level of microRNA-671-5p in periodontal tissues of patients with periodontitis was increased. In this study, we investigated the mechanism of action of microRNA-671-5p in human periodontal ligament stem cells (hPDLSCs) under inflammatory conditions.

METHODS AND RESULTS

HPDLSCs were treated with lipopolysaccharide (LPS) to establish an inflammation model. The cell survival rate was determined using the cell counting kit-8 (CCK8). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analyses were used to detect the expression of microRNA-671-5p and dual-specificity phosphatase (DUSP) 8 proteins, respectively, Interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were detected using qRT-PCR and Enzyme-linked immunosorbent assay (ELISA). A dual-luciferase reporter system was employed to determine the relationship between micoRNA-671-5p and DUSP8 expression. Activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway was confirmed using western blot analysis. Following the treatment of hPDLSCs with LPS, the expression levels of microRNA-671-5p in hPDLSCs were increased, cell viability decreased, and the expression of inflammatory factors displayed an increasing trend. MicroRNA-671-5p targets and binds to DUSP8. Silencing microRNA-671-5p or overexpressing DUSP8 can improve cell survival rate and reduce inflammatory responses. When DUSP8 was overexpressed, the expression of p-p38 was reduced.

CONCLUSIONS

microRNA-671-5p targets DUSP8/p38 MAPK pathway to regulate LPS-induced proliferation and inflammation in hPDLSCs.

A literature review of bioactive substances for the treatment of periodontitis: In vitro, in vivo and clinical studies

Periodontitis is a common chronic inflammatory disease of the supporting tissues of the tooth that involves a complex interaction of microorganisms and various cell lines around the infected site. To prevent and treat this disease, several options are available, such as scaling, root planning, antibiotic treatment, and dental surgeries, depending on the stage of the disease. However, these treatments can have various side effects, including additional inflammatory responses, chronic wounds, and the need for secondary surgery. Consequently, numerous studies have focused on developing new therapeutic agents for more effective periodontitis treatment. This review explores the latest trends in bioactive substances with therapeutic effects for periodontitis using various search engines. Therefore, this study aimed to suggest effective directions for therapeutic approaches. Additionally, we provide a summary of the current applications and underlying mechanisms of bioactive substances, which can serve as a reference for the development of periodontitis treatments.

Circ_0138960 contributes to lipopolysaccharide-induced periodontal ligament cell dysfunction

BACKGROUND

Periodontitis is a common oral inflammatory disease, and lipopolysaccharide (LPS) is a key risk factor in periodontitis pathology. Here, we used LPS-induced periodontal ligament cells (PDLCs) to explore the molecular mechanism of periodontitis.

METHODS

Cell viability, proliferation, and apoptosis were analyzed by Cell Counting Kit-8, 5-ethynyl-20-deoxyuridine (EDU), and flow cytometry assays, respectively. Apart from that, their targeting relationship was validated using dual-luciferase reporter and RNA-pull down.

RESULTS

Circular RNA_0138960 (circ_0138960) was notably upregulated in periodontitis sufferers (p < .001) and LPS-disposed PDLCs (p < .05). LPS exposure dampened PDLC proliferation, and promoted apoptosis and inflammation (p < .05). Circ_0138960 acted as a microRNA sponge for miR-518a-5p to affect histone deacetylase 6 (HDAC6) expression. Circ_0138960 absence-mediated protective effects in LPS-induced PDLCs were largely abrogated via silencing miR-518a-5p or HDAC6 overexpression (p < .05).

CONCLUSION

Circ_0138960 promoted LPS-induced dysfunction in PDLCs by targeting miR-518a-5p/HDAC6 axis, which provided novel potential therapeutic targets for periodontitis.

Inhibitory Effect of Periodontitis through C/EBP and 11β-Hydroxysteroid Dehydrogenase Type 1 Regulation of Betulin Isolated from the Bark of Betula platyphylla

Periodontitis is an infectious inflammatory disease of the tissues around the tooth that destroys connective tissue and is characterized by loss of periodontal ligaments and alveolar bone. Currently, surgical methods for the treatment of periodontitis have limitations and new treatment strategies are needed. Therefore, this study evaluated the efficacy of the compound betulin isolated from bark of Betula platyphylla on the inhibition of periodontitis in vitro and in vivo periodontitis induction models. In the study, betulin inhibited pro-inflammatory mediators, such as tumor necrosis factor, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2, in human periodontal ligament cells stimulated with Porphyromonas gingivalis lipopolysaccharide (PG-LPS). In addition, it showed an anti-inflammatory effect by down-regulating 11β-hydroxysteroid dehydrogenase type 1 and transcription factor C/EBP β produced by PG-LPS. Moreover, PG-LPS inhibited the osteogenic induction of human periodontal ligament cells. The protein and mRNA levels of osteogenic markers, such as inhibited osteopontin (OPN) and runt-related transcription factor 2 (RUNX2), were regulated by betulin. In addition, the efficacy of betulin was demonstrated in a typical in vivo model of periodontitis induced by PG-LPS, and the results showed through hematoxylin & eosin staining and micro-computed tomography that the administration of betulin alleviated alveolar bone loss and periodontal inflammation caused by PG-LPS. Therefore, this study proved the efficacy of the compound betulin isolated from B. platyphylla in the inhibition of periodontitis and alveolar bone loss, two important strategies for the treatment of periodontitis, suggesting the potential as a new treatment for periodontitis.

Therapeutic Effect of Acer tegmentosum Maxim Twig Extract in Bile Duct Ligation-Induced Acute Cholestasis in Mice

Cholestatic liver disease, or cholestasis, is a condition characterized by liver inflammation and fibrosis following a bile duct obstruction and an intrahepatic accumulation of bile acids. Inhibiting inflammation is a promising therapeutic strategy for cholestatic liver diseases. Acer tegmentosum Maxim extract (ATE) is best known for its anti-inflammatory and antioxidative properties. In this study, we investigated the effects of ATE on liver injury and fibrosis in mice with bile duct ligation (BDL)-induced cholestasis through analysis of gene expression, cytokines, and histological examination. Oral administration of ATE (20 or 50 mg/kg) for 14 days significantly attenuated hepatocellular necrosis compared to vehicle-treated BDL mice, which was accompanied by the reduced level of serum bile acids and bilirubin. We determined that ATE treatment reduced liver inflammation, oxidative stress, and fibrosis. These beneficial effects of ATE were concurrent with the decreased expression of genes involved in the NF-κB pathway, suggesting that the anti-inflammatory effect of ATE could be a possible mechanism against cholestasis-associated liver injury. Our findings substantiate ATE's role as an alternative therapeutic agent for cholestasis-induced liver injury and fibrosis.

Oral and Gut Microbial Dysbiosis and Non-alcoholic Fatty Liver Disease: The Central Role of Porphyromonas gingivalis

Gut microbiota play many important roles, such as the regulation of immunity and barrier function in the intestine, and are crucial for maintaining homeostasis in living organisms. The disruption in microbiota is called dysbiosis, which has been associated with various chronic inflammatory conditions, food allergies, colorectal cancer, etc. The gut microbiota is also affected by several other factors such as diet, antibiotics and other medications, or bacterial and viral infections. Moreover, there are some reports on the oral-gut-liver axis indicating that the disruption of oral microbiota affects the intestinal biota. Non-alcoholic fatty liver disease (NAFLD) is one of the systemic diseases caused due to the dysregulation of the oral-gut-liver axis. NAFLD is the most common liver disease reported in the developed countries. It includes liver damage ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), cirrhosis, and cancer. Recently, accumulating evidence supports an association between NAFLD and dysbiosis of oral and gut microbiota. Periodontopathic bacteria, especially Porphyromonas gingivalis, have been correlated with the pathogenesis and development of NAFLD based on the clinical and basic research, and immunology. P. gingivalis was detected in the liver, and lipopolysaccharide from this bacteria has been shown to be involved in the progression of NAFLD, thereby indicating a direct role of P. gingivalis in NAFLD. Moreover, P. gingivalis induces dysbiosis of gut microbiota, which promotes the progression of NAFLD, through disrupting both metabolic and immunologic pathways. Here, we review the roles of microbial dysbiosis in NAFLD. Focusing on P. gingivalis, we evaluate and summarize the most recent advances in our understanding of the relationship between oral-gut microbiome symbiosis and the pathogenesis and progression of non-alcoholic fatty liver disease, as well as discuss novel strategies targeting both P. gingivalis and microbial dysbiosis.

Natural Killer-Like B Cells Secreting Interleukin-18 Induces a Proinflammatory Response in Periodontitis

Natural killer-like B (NKB) cells, which are newly identified immune subsets, reveal a critical immunoregulatory property in the eradication of microbial infection via the secretion of interleukin (IL)-18. For the first time, this study investigated the role of NKB cells in secreting IL-18 in the pathogenesis of periodontitis. In this study, NKB cells' percentage and IL-18 concentration in peripheral blood and periodontium in periodontitis patients was measured using flow cytometry and ELISA. The role of IL-18 in regulating periodontal inflammation was examined in a Porphyromonas gingivalis (P. gingivalis)-induced periodontitis murine model. Peripheral and periodontal-infiltrating CD3^-CD19⁺NKp46⁺ NKB cells, which were the main source of IL-18, were elevated and correlated with attachment loss in periodontitis patients. In vitro IL-18 stimulation promoted proinflammatory cytokine production in periodontal ligament cells. P. gingivalis infection induced elevation of IL-18 receptor in periodontium in a periodontitis murine model. IL-18 neutralization not only suppressed P. gingivalis-induced alveolar bone resorption, but also inhibited recruitment of antigen-non-specific inflammatory cells into the periodontium, probably via dampening expressions of cytokines, chemokines, and matrix metalloproteinases. NKB cells secreting IL-18 appeared to be an important mediator in the inflammatory response following intraoral P. gingivalis infection. These findings might be relevant to the development of immunotherapies for periodontitis.

Circ_0081572 inhibits the progression of periodontitis through regulating the miR-378h/RORA axis

OBJECTIVES

Revealing the role and mechanism of circ_0081572 in periodontitis progression.

DESIGN

Quantitative real-time PCR (qRT-PCR) was applied to measure the expression of circ_0081572, microRNA (miR)-378h and retinoid acid-related orphan receptor A (RORA). Lipopolysaccharide (LPS) was used to treat periodontal ligament cells (PDLCs) to construct periodontitis cell model in vitro. Cell counting kit 8 (CCK8) assay and flow cytometry were used to measure cell viability and apoptosis. The caspase 3 activity was detected by Caspase 3 Activity Assay Kit. Western blot assay was performed to detect the expression of apoptosis-associated proteins and RORA. The inflammation response and oxidative stress were determined by detecting the levels of inflammatory cytokines and reactive oxygen species (ROS). The relationship between miR-378h and circ_0081572 or RORA was verified by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and biotin-labeled RNA pull-down assay.

RESULTS

Circ_0081572 was a stability circRNA with downregulated expression in the gingival tissues of periodontitis patients. Overexpression of circ_0081572 could alleviate LPS-induced PDLCs injury. Circ_0081572 could serve as a sponge for miR-378h. Furthermore, miR-378h could reverse the inhibition of circ_0081572 on LPS-induced PDLCs injury. In addition, RORA could be targeted by miR-378h, and its silencing could reverse the suppressive effect of miR-378h inhibitor and circ_0081572 overexpression on LPS-induced PDLCs injury.

CONCLUSIONS

Our results suggested that circ_0081572 might prevent periodontitis by regulating the miR-378h /RORA axis.

Agrimonia pilosa Ledeb Root Extract: Anti-Inflammatory Activities of the Medicinal Herb in LPS-Induced Inflammation

Inflammation regulation is essential for maintaining healthy functions and normal homeostasis of the body. Porphyromonas gingivalis (P. gingivalis) is a gram-negative anaerobic bacterium and a major pathogen that causes oral inflammation and other systemic inflammations. This study aims to examine the anti-inflammatory effects of Agrimonia pilosa Ledeb root extracts (APL-ME) in Porphyromonas gingivalis LPS-induced RAW 264.7 cells and find anti-inflammatory effect compounds of APL-ME. The anti-inflammatory effects of APL-ME were evaluated anti-oxidant activity, cell viability, nitrite concentration, pro-inflammatory cytokines (interleukin-1[Formula: see text], interleukin-6, tumor necrosis factor (TNF)-[Formula: see text], and anti-inflammatory cytokine (interleukin-10 (IL-10)). Also, Inflammation related genes and proteins, cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), expression were decreased by APL-ME and mitogen-activated protein kinase (MAPK) signaling proteins expression was regulated by APL-ME. Liquid chromatography-mass spectrometer (LC/MS)-MS analysis results indicated that several components were detected in APL-ME. Our study indicated that APL-ME suppressed nitrite concentrations, pro-inflammatory cytokines such as IL-1[Formula: see text], IL-6 and TNF-[Formula: see text] in P. gingivalis LPS induced RAW 264.7 cells. However, IL-10 expression was increased by ALP-ME. In addition, protein expressions of COX-2 and iNOS were inhibited APL-ME extracts dose-dependently. According to these results, APL-ME has anti-inflammatory effects in P. gingivalis LPS induced RAW 264.7 cells.

Panax ginseng Fruit Has Anti-Inflammatory Effect and Induces Osteogenic Differentiation by Regulating Nrf2/HO-1 Signaling Pathway in In Vitro and In Vivo Models of Periodontitis

Periodontitis is an infectious inflammatory disease of tissues around teeth that destroys connective tissues and is characterized by the loss of periodontal ligaments and alveolar bone. A new treatment strategy is needed owing to the limitations of the current surgical treatment method and the side effects of anti-inflammatory drugs. Therefore, here, we assessed whether Panax ginseng fruit extract (PGFE) is a new therapeutic agent for periodontitis in vitro and in vivo. According to the results, PGFE suppressed pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, and pro-inflammatory mediators such as inducible nitric oxide synthase and cyclooxygenase-2 through heme oxygenase-1 expression in human periodontal ligament cells stimulated with Porphyromonas gingivalis lipopolysaccharide (PG-LPS). In addition, the osteogenic induction of human periodontal ligament cells was inhibited by PG-LPS, and protein and mRNA levels of osteogenic markers such as alkaline phosphatase, collagen type 1 (COL1), osteopontin (OPN), and runt-related transcription factor 2 (RUNX2) were increased. The efficacy of PGFE for inhibiting periodontitis in vitro was demonstrated in a representative in vitro model of periodontitis induced by ligature and PG-LPS. Subsequently, hematoxylin and eosin staining and micro-computed tomography of the euthanized experimental animal model confirmed suppressed periodontal inflammation, which is an important strategy for treating periodontitis and for recovering the resulting alveolar bone loss. Therefore, PGFE is a potential, novel therapeutic agent for periodontal diseases.