Circ_0036490 and DKK1 competitively bind miR-29a to promote lipopolysaccharides-induced human gingival fibroblasts injury

MicroRNA (miRNA) plays a regulatory role in periodontitis. This study aimed to explore whether miR-29a could affect lipopolysaccharides (LPSs)-induced injury in human gingival fibroblasts (HGFs) through the competitive endogenous RNAs (ceRNA) mechanism. Periodontal ligament (PDL) tissues and HGFs were derived from patients with periodontitis and healthy volunteers. Periodontitis cell model was established by treating HGFs with LPS. Expression levels of circ_0036490, miR-29a, and DKK1 were evaluated by the reverse transcription quantitative real-time PCR (RT-qPCR) method. Western blotting assay was performed to assess protein expression levels of pyroptosis-related proteins and Wnt signalling related proteins. Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. Concentration of lactate dehydrogenase (LDH), interleukin (IL)-1β, and IL-18 were determined by Enzyme-linked immunosorbent assay (ELISA). Pyroptosis rate were determined by flow cytometry assay to evaluate pyroptosis. The interaction between miR-29a and circ_0036490 or DKK1 was verified by dual-luciferase reporter and RNA pull-down assays. MiR-29a expression was lower in PDL tissues of patients with periodontitis than that in healthy group; likewise, miR-29a was also downregulated in LPS-treated HGFs. Overexpression of miR-29a increased cell viability and decreased pyroptosis of HGFs induced by LPS while inhibition of miR-29a exerted the opposite role. MiR-29a binds to circ_0036490 and elevation of circ_0036490 contributed to dysfuntion of LPS-treated HGFs and reversed the protection function of elevated miR-29a. In addition, miR-29a targets DKK1. Overexpression of DKK1 abrogated the effects of overexpressed miR-29a on cell vaibility, pyroptosis, and protein levels of Wnt signalling pathway of LPS-treated HGFs. Circ_0036490 and DKK1 competitively bind miR-29a to promote LPS-induced HGF injury in vitro. Wnt pathway inactivated by LPS was activated by miR-29a. Thence, miR-29a may be a promising target for periodontitis.

The role of periodontitis in cancer development, with a focus on oral cancers

Periodontitis is a severe gum infection that begins as gingivitis and can lead to gum recession, bone loss, and tooth loss if left untreated. It is primarily caused by bacterial infection, which triggers inflammation and the formation of periodontal pockets. Notably, periodontitis is associated with systemic health issues and has been linked to heart disease, diabetes, respiratory diseases, adverse pregnancy outcomes, and cancers. Accordingly, the presence of chronic inflammation and immune system dysregulation in individuals with periodontitis significantly contributes to the initiation and progression of various cancers, particularly oral cancers. These processes promote genetic mutations, impair DNA repair mechanisms, and create a tumor-supportive environment. Moreover, the bacteria associated with periodontitis produce harmful byproducts and toxins that directly damage the DNA within oral cells, exacerbating cancer development. In addition, chronic inflammation not only stimulates cell proliferation but also inhibits apoptosis, causes DNA damage, and triggers the release of pro-inflammatory cytokines. Collectively, these factors play a crucial role in the progression of cancer in individuals affected by periodontitis. Further, specific viral and bacterial agents, such as hepatitis B and C viruses, human papillomavirus (HPV), Helicobacter pylori (H. pylori), and Porphyromonas gingivalis, contribute to cancer development through distinct mechanisms. Bacterial infections have systemic implications for cancer development, while viral infections provoke immune and inflammatory responses that can lead to genetic mutations. This review will elucidate the link between periodontitis and cancers, particularly oral cancers, exploring their underlying mechanisms to provide insights for future research and treatment advancements.

Reduction of osteoclast formation and survival following suppression of cytokines by diacerein in periodontitis

Periodontitis causes an increase in several bioactive agents such as interleukins (IL), tumor necrosis factor (TNF)-α and receptor activator of NF-kB ligand (RANKL), which induce the osteoclast formation and activity. Since diacerein exerts anti-TNF-α and anti-IL-1 effects, alleviating bone destruction in osteoarthritis, we investigated whether this drug inhibits the formation and survival of osteoclast in the periodontitis. Rats were distributed into 3 groups: 1) group with periodontitis treated with 100 mg/kg diacerein (PDG), 2) group with periodontitis treated with saline (PSG) and group control (CG) without any treatment. After 7, 15 and 30 days, the maxillae were collected for light and transmission electron microscopy analyses. Gingiva samples were collected to evaluate the mRNA levels for Tnf, Il1b, Tnfsf11 and Tnfrsf11b by RT-qPCR. In PDG, the expression of Tnf and Il1b genes reduced significantly compared to PSG, except for Tnf expression at 7 days. The number of osteoclasts reduced significantly in the PDG in comparison with PSG at 7 and 15 days. In all periods, the IL-6 immunoexpression, RANKL/OPG immunoexpression and mRNA levels of Tnfsf11/Tnfrsf11b ratio were significantly lower in PDG than in PSG. PDG exhibited significantly higher frequency of TUNEL-positive osteoclasts than in PSG and CG at all time points. Osteoclasts with caspase-3-immunolabelled cytoplasm and nuclei with masses of condensed chromatin were observed in PDG, confirming osteoclast apoptosis. Diacerein inhibits osteoclastogenesis by decreasing Tnf and Il1b mRNA levels, resulting in decreased RANKL/OPG ratio, and induces apoptosis in osteoclasts of alveolar process of rat molars with periodontitis.

Periodontal disease and emerging point-of-care technologies for its diagnosis

Periodontal disease (PD), a chronic inflammatory disorder that damages the tooth and its supporting components, is a common global oral health problem. Understanding the intricacies of these disorders, from gingivitis to severe PD, is critical for efficient treatment, diagnosis, and prevention in dental care. Periodontal biosensors and biomarkers are critical in improving oral health diagnostic skills. Clinicians may accomplish early identification, tailored therapy, and efficient tracking of periodontal diseases by using these technologies, ushering in a new age of accurate oral healthcare. Traditional periodontitis diagnostic methods frequently rely on physical probing and visual examinations, necessitating the development of point-of-care (POC) devices. As periodontal disorders necessitate more precise and rapid diagnosis, incorporating novel innovations in biosensors and biomarkers becomes increasingly crucial. These innovations improve our capacity to diagnose, monitor, and adapt periodontal therapies, bringing in the next phase of customized and effective dental healthcare. The review discusses the characteristics and stages of PD, clinical treatment techniques, prominent biomarkers and infection-associated factors that may be employed to determine PD, biomedical sensing, and POC appliances that have been created so far to diagnose stages of PD and its progression profile, as well as predicting future developments in this field.

A new direction in periodontitis treatment: biomaterial-mediated macrophage immunotherapy

Periodontitis is a chronic inflammation caused by a bacterial infection and is intimately associated with an overactive immune response. Biomaterials are being utilized more frequently in periodontal therapy due to their designability and unique drug delivery system. However, local and systemic immune response reactions driven by the implantation of biomaterials could result in inflammation, tissue damage, and fibrosis, which could end up with the failure of the implantation. Therefore, immunological adjustment of biomaterials through precise design can reduce the host reaction while eliminating the periodontal tissue's long-term chronic inflammation response. It is important to note that macrophages are an active immune system component that can participate in the progression of periodontal disease through intricate polarization mechanisms. And modulating macrophage polarization by designing biomaterials has emerged as a new periodontal therapy technique. In this review, we discuss the role of macrophages in periodontitis and typical strategies for polarizing macrophages with biomaterials. Subsequently, we discuss the challenges and potential opportunities of using biomaterials to manipulate periodontal macrophages to facilitate periodontal regeneration.

Galectin-3 inhibition alleviated LPS-induced periodontal inflammation in gingival fibroblasts and experimental periodontitis mice

OBJECTIVES

Clinical studies have confirmed that galectin-3 (Gal-3) levels are significantly elevated in periodontitis patients. The present study aimed to explore the effects of Gal-3 inhibition on periodontal inflammation in vitro and in vivo.

METHODS

Human gingival fibroblasts (HGFs) with or without Gal-3 knockdown were stimulated by lipopolysaccharide (LPS), and a ligation-induced mouse periodontitis model treated with a Gal-3 inhibitor was established. Hematoxylin-eosin (H&E) and immunohistochemistry (IHC) staining were used to evaluate Gal-3 levels in gingival tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect Gal-3, interleukin (IL)-6, IL-8, and C-C motif ligand 2 (CCL2) expression. Immunofluorescence and western blotting were used to detect NF-κB and ERK signaling pathway activation. Micro-computed tomography was used to analyse the degree of bone loss.

RESULTS

Gal-3 was significantly up-regulated in inflamed gingival tissues and LPS-induced HGFs. Gal-3 knockdown markedly decreased LPS-induced IL-6, IL-8, and CCL2 expression and blocked NF-κB and ERK signaling pathway activation in HGFs. In the mouse periodontitis model, Gal-3 inhibition significantly alleviated IL-1β and IL-6 infiltration in gingival tissue and mitigated periodontal bone loss.

CONCLUSIONS

Gal-3 inhibition notably alleviated periodontal inflammation partly through blocking NF-κB and ERK signaling pathway activation.

Long intergenic non-coding RNA 01126 activates IL-6/JAK2/STAT3 pathway to promote periodontitis pathogenesis

OBJECTIVES

Periodontitis seriously affects oral-related quality of life and overall health. Long intergenic non-coding RNA 01126 (LINC01126) is aberrantly expressed in periodontitis tissues. This study aimed to explore the possible pathogenesis of LINC01126 in periodontitis.

METHODS

Inflammatory model of human gingival fibroblasts (HGFs) was established. Cell Counting Kit-8 (CCK-8), wound healing assay, and flow cytometry were utilized to detect biological roles of LINC01126. Binding site of miR-655-3p to LINC01126 and IL-6 was predicted. Then, subcellular localization of LINC01126 and the binding ability of miR-655-3p to LINC01126 and IL-6 in HGFs were verified. Hematoxylin-Eosin (H&E) staining and immunohistochemistry (IHC) staining were utilized to detect tissue morphology and proteins expression of clinical samples.

RESULTS

LINC01126 silencing can alleviate cell inflammation induced by lipopolysaccharide derived from Porphyromonas gingivalis, reduce cell apoptosis, and promote cell migration. As a "sponge" for miR-655-3p, LINC01126 inhibits its binding to mRNA of IL-6, thereby promoting inflammation progression and JAK2/STAT3 pathway activation. Quantitative real-time PCR, Western Blot, and IHC results of clinical tissue samples further confirmed that miR-655-3p expression was down-regulated and IL-6/JAK2/STAT3 was abnormally activated in periodontitis tissues.

CONCLUSIONS

In summary, serving as an endogenous competitive RNA of miR-655-3p, LINC01126 promotes IL-6/JAK2/STAT3 pathway activation, thereby promoting periodontitis pathogenesis.

Differential expression of FSTL1 and its correlation with the pathological process of periodontitis

AIMS

This study aimed to elucidate the alterations in Follistatin-like protein 1 (FSTL1) and its association with the pathological process of periodontitis.

METHODS

This study included 48 patients with periodontitis and 42 healthy controls. The expression level of FSTL1 in the gingiva was determined by RT-qPCR, validated using the dataset GSE16134, and subsequently examined by western blotting. Bioinformatics analysis revealed a single-cell distribution of FSTL1, characteristic of angiogenesis and immune cell infiltration. The expression and distribution of FSTL1, vascular endothelial marker protein CD31 and myeloperoxidase (MPO), the indicator of neutrophil activity, were determined by immunohistochemistry (IHC). A series of correlation analyses was performed to determine the associations between FSTL1 and clinical parameters, including probing depth (PD) and clinical attachment loss (CAL), and their potential role in angiogenesis (CD31) and neutrophil infiltration (MPO).

RESULTS

FSTL1 was significantly upregulated in the gingiva of patients with periodontitis compared to their healthy counterparts. In addition, FSTL1 was positively correlated with the clinical parameters PD (r = .5971, p = .0005) and CAL (r = .6078, p = .0004). Bioinformatic analysis and IHC indicated that high FSTL1 expression was significantly correlated with angiogenesis and neutrophil infiltration in periodontitis. Moreover, receiver operating characteristic (ROC) analysis demonstrated that FSTL1 could serve as an independent indicator for evaluating the severity of periodontitis (area under the curve [AUC] = 0.9011, p < .0001).

CONCLUSION

This study demonstrated FSTL1 upregulation in periodontitis and its potential contribution to the disease via angiogenesis and neutrophil infiltration.

A multi-platform analysis of human gingival crevicular fluid reveals ferroptosis as a relevant regulated cell death mechanism during the clinical progression of periodontitis

Ferroptosis is implicated in the pathogenesis of numerous chronic-inflammatory diseases, yet its association with progressive periodontitis remains unexplored. To investigate the involvement and significance of ferroptosis in periodontitis progression, we assessed sixteen periodontitis-diagnosed patients. Disease progression was clinically monitored over twelve weeks via weekly clinical evaluations and gingival crevicular fluid (GCF) collection was performed for further analyses. Clinical metrics, proteomic data, in silico methods, and bioinformatics tools were combined to identify protein profiles linked to periodontitis progression and to explore their potential connection with ferroptosis. Subsequent western blot analyses validated key findings. Finally, a single-cell RNA sequencing (scRNA-seq) dataset (GSE164241) for gingival tissues was analyzed to elucidate cellular dynamics during periodontitis progression. Periodontitis progression was identified as occurring at a faster rate than traditionally thought. GCF samples from progressing and non-progressing periodontal sites showed quantitative and qualitatively distinct proteomic profiles. In addition, specific biological processes and molecular functions during progressive periodontitis were revealed and a set of hub proteins, including SNCA, CA1, HBB, SLC4A1, and ANK1 was strongly associated with the clinical progression status of periodontitis. Moreover, we found specific proteins - drivers or suppressors - associated with ferroptosis (SNCA, FTH1, HSPB1, CD44, and GCLC), revealing the co-occurrence of this specific type of regulated cell death during the clinical progression of periodontitis. Additionally, the integration of quantitative proteomic data with scRNA-seq analysis suggested the susceptibility of fibroblasts to ferroptosis. Our analyses reveal proteins and processes linked to ferroptosis for the first time in periodontal patients, which offer new insights into the molecular mechanisms of progressive periodontal disease. These findings may lead to novel diagnostic and therapeutic strategies.

Unraveling Divergent Transcriptomic Profiles: A Comparative Single-Cell RNA Sequencing Study of Epithelium, Gingiva, and Periodontal Ligament Tissues

The periodontium comprising periodontal ligament (PDL), gingiva, and epithelium play crucial roles in maintaining tooth integrity and function. Understanding tissue cellular composition and gene expression is crucial for illuminating periodontal pathophysiology. This study aimed to identify tissue-specific markers via scRNA-Seq. Primary human PDL, gingiva, and epithelium tissues (n = 7) were subjected to cell hashing and sorting. scRNA-Seq library preparation using 10× Genomics protocol and Illumina sequencing was conducted. The analysis was performed using Cellranger (v3.1.0), with downstream analysis via R packages Seurat (v5.0.1) and SCORPIUS (v1.0.9). Investigations identified eight distinct cellular clusters, revealing the ubiquitous presence of epithelial and gingival cells. PDL cells evolved in two clusters with numerical superiority. The other clusters showed varied predominance regarding gingival and epithelial cells or an equitable distribution of both. The cluster harboring most cells mainly consisted of PDL cells and was present in all donors. Some of the other clusters were also tissue-inherent, while the presence of others was environmentally influenced, revealing variability across donors. Two clusters exhibited genetic profiles associated with tissue development and cellular integrity, respectively, while all other clusters were distinguished by genes characteristic of immune responses. Developmental trajectory analysis uncovered that PDL cells may develop after epithelial and gingival cells, suggesting the inherent PDL cell-dominated cluster as a final developmental stage. This single-cell RNA sequencing study delineates the hierarchical organization of periodontal tissue development, identifies tissue-specific markers, and reveals the influence of environmental factors on cellular composition, advancing our understanding of periodontal biology and offering potential insights for therapeutic interventions.

IL-33 in patients with periodontitis and chronic obstructive pulmonary disease

OBJECTIVE

A link between periodontitis and chronic obstructive pulmonary disease (COPD) has been identified, and interleukin-33 (IL-33) may play an important role in the common inflammatory mechanisms of these diseases. This study analyzed the associations of the serum IL-33 level with the occurrence and severity of periodontitis and COPD.

METHODS

A total of 161 participants were divided into four groups: healthy volunteers, periodontitis patients, COPD patients, and patients with both COPD and periodontitis. Associations between serum IL-33 levels were measured by enzyme-linked immunosorbent assay, and clinical factors as well as the risks and severity of periodontitis and COPD were analyzed.

RESULTS

Serum IL-33 levels were lower in all patient groups than in healthy controls. A trend toward lower IL-33 levels was observed among patients with both diseases compared with patients with either disease alone. The serum IL-33 level was also inversely associated with the severity of periodontitis and COPD. The serum IL-33 level was negatively associated with risks of periodontitis and COPD, indicating that IL-33 is likely involved in the pathophysiologic mechanism of the relationship between COPD and periodontitis.

CONCLUSION

This study advances our understanding of the association between COPD and periodontitis and provides new bases for COPD prevention and treatment.

In Vitro Cytotoxic and Inflammatory Response of Gingival Fibroblasts and Oral Mucosal Keratinocytes to 3D Printed Oral Devices

The purpose of this study was to examine the biocompatibility of 3D printed materials used for additive manufacturing of rigid and flexible oral devices. Oral splints were produced and finished from six printable resins (pairs of rigid/flexible materials: KeySplint Hard [KR], KeySplint Soft [KF], V-Print Splint [VR], V-Print Splint Comfort [VF], NextDent Ortho Rigid [NR], NextDent Ortho Flex [NF]), and two types of PMMA blocks for subtractive manufacturing (Tizian Blank PMMA [TR], Tizian Flex Splint Comfort [TF]) as controls. The specimens were eluted in a cell culture medium for 7d. Human gingival fibroblasts (hGF-1) and human oral mucosal keratinocytes (hOK) were exposed to the eluates for 24 h. Cell viability, glutathione levels, apoptosis, necrosis, the cellular inflammatory response (IL-6 and PGE2 secretion), and cell morphology were assessed. All eluates led to a slight reduction of hGF-1 viability and intracellular glutathione levels. The strongest cytotoxic response of hGF-1 was observed with KF, NF, and NR eluates (p < 0.05 compared to unexposed cells). Viability, caspase-3/7 activity, necrosis levels, and IL-6/PGE2 secretion of hOK were barely affected by the materials. All materials showed an overall acceptable biocompatibility. hOK appeared to be more resilient to noxious agents than hGF-1 in vitro. There is insufficient evidence to generalize that flexible materials are more cytotoxic than rigid materials. From a biological point of view, 3D printing seems to be a viable alternative to milling for producing oral devices.

Cell culture on suspended fiber for tissue regeneration: A review

Cell culturing is a cornerstone of tissue engineering, playing a crucial role in tissue regeneration, drug screening, and the study of disease mechanisms. Among various culturing techniques, 3D culture systems, particularly those utilizing suspended fiber scaffolds, offer a more physiologically relevant environment than traditional 2D monolayer cultures. These 3D scaffolds enhance cell growth, differentiation, and proliferation by mimicking the in vivo cellular milieu. This review focuses on the critical role of suspended fiber scaffolds in tissue engineering. We compare the effectiveness of 3D suspended fiber scaffolds with 2D culture systems, discussing their respective benefits and limitations in the context of tissue regeneration. Furthermore, we explore the preparation methods of suspended fiber scaffolds and their potential applications. The review concludes by considering future research directions for optimizing suspended fiber scaffolds to address specific challenges in tissue regeneration, underscoring their significant promise in advancing tissue engineering and regenerative medicine.

Extracellular adenosine triphosphate regulates inflammatory responses of periodontal ligament cells

BACKGROUND

Various stimuli, that is, mechanical stresses or inflammation, induce the release of adenosine triphosphate (ATP) by human periodontal ligament cells (HPDLCs). Extracellular adenosine triphosphate (eATP) affects HPDLCs' functions such as immunosuppressive action and inflammatory responses. Lipopolysaccharide (LPS) is the key factor involved in periodontal inflammation. However, the possible correlation and detailed mechanism of inflammation-mediated eATP by LPS and inflammatory cascade formation in HPDLCs is unclarified. This study aims to examine the role of eATP on the HPDLCs' responses concerning inflammatory actions after LPS treatment.

METHODS

HPDLCs were stimulated with Porphyromonas gingivalis LPS and polyinosinic:polycytidylic acid (poly I:C). The amount of ATP release was measured at different time points using a bioluminescence assay. HPDLCs were treated with eATP. The expression of pro-inflammatory and anti-inflammatory genes was determined. Specific P2X purinoreceptor 7 (P2X7) inhibitors (brilliant blue G [BBG] and KN62), a specific P2Y purinoreceptor 1 (P2Y1) inhibitors (MRS2179), calcium chelator (EGTA), protein kinase C (PKC) inhibitors, nuclear factor kappa-light-chain-enhancer of activated B cells (NF𝜅B) activation inhibitors, and cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) inhibitors (H89 dihydrochloride) and activators (forskolin) were used to dissect the mechanism of eATP-induced HPDLCs' inflammatory responses.

RESULTS

LPS and poly I:C induced ATP release. A low concentration of eATP (50 µM) increased pro-inflammatory genes (COX2, IL1B, IL6, IL8, IL12, and TNFA), while a high concentration (500 µM) enhanced anti-inflammatory genes (IL4 and IL10). BBG, KN62, and NF𝜅B activation inhibitors impeded eATP-induced pro-inflammatory genes. MRS2179 and H89 markedly suppressed eATP-induced anti-inflammatory genes. Forskolin induced IL4 and IL10.

CONCLUSION

HPDLCs respond to LPS by releasing ATP. eATP has dose-dependent dual functions on HPDLCs' inflammatory responses via different pathways. As regulation of inflammation is important in regeneration, eATP may help to limit inflammation and trigger periodontal regeneration.

Pharmacological induction of autophagy reduces inflammation in macrophages by degrading immunoproteasome subunits

Defective autophagy is linked to proinflammatory diseases. However, the mechanisms by which autophagy limits inflammation remain elusive. Here, we found that the pan-FGFR inhibitor LY2874455 efficiently activated autophagy and suppressed expression of proinflammatory factors in macrophages stimulated by lipopolysaccharide (LPS). Multiplex proteomic profiling identified the immunoproteasome, which is a specific isoform of the 20s constitutive proteasome, as a substrate that is degraded by selective autophagy. SQSTM1/p62 was found to be a selective autophagy-related receptor that mediated this degradation. Autophagy deficiency or p62 knockdown blocked the effects of LY2874455, leading to the accumulation of immunoproteasomes and increases in inflammatory reactions. Expression of proinflammatory factors in autophagy-deficient macrophages could be reversed by immunoproteasome inhibitors, confirming the pivotal role of immunoproteasome turnover in the autophagy-mediated suppression on the expression of proinflammatory factors. In mice, LY2874455 protected against LPS-induced acute lung injury and dextran sulfate sodium (DSS)-induced colitis and caused low levels of proinflammatory cytokines and immunoproteasomes. These findings suggested that selective autophagy of the immunoproteasome was a key regulator of signaling via the innate immune system.

Association of per- and polyfluoroalkyl substances (PFAS) with periodontitis: the mediating role of sex hormones

OBJECTIVES

To investigate the association between serum per- and polyfluoroalkyl substances (PFAS) and periodontitis, and further explore the possible mediating role of sex hormones in this association.

METHODS

We extracted data from National Health and Nutrition Examination Survey (NHANES) 2009-2014. Univariable and multivariable logistic regression models were performed to investigate the association between serum levels of seven PFASs and periodontitis. Bayesian kernel machine regression (BKMR) was conducted to assess the joint effect of PFASs in mixtures. Mediation analyses were used to explore the potential mediating role of sex hormones.

RESULTS

Participants with periodontitis had higher concentrations of serum perfluorooctane sulfonate (PFOS) and perfluorononanoic acid (PFNA) than those without periodontitis (both P < 0.05). In fully adjusted models, high serum concentrations of PFOS and PFNA were positively associated with periodontitis (tertile 3 vs. tertile 1: prevalence ratio (PR) = 1.19 for PFOS, 95% CI: 1.01-1.39; PR = 1.17 for PFNA, 95% CI: 1.02-1.34). The results from the BKMR models consistently showed a positive association between PFAS mixtures and periodontitis. Of note, testosterone and the ratio of testosterone to estradiol significantly mediated the relationship between high level of PFOS and periodontitis, accounting for 16.5% and 31.7% of the total effect, respectively. Sensitivity analyses yielded similar results when using periodontal clinical indices (mean loss of attachment, mean periodontal probing depth, and the number of teeth) as dependent variables.

CONCLUSIONS

These findings provide evidence to support a positive association between certain PFASs and periodontitis, which might be partially mediated by sex hormones.

The Role of Interleukin 6 in Periodontitis and Its Complications

Interleukin 6 (IL-6) is a pleomorphic pro-inflammatory cytokine that is strongly associated with local as well as systemic inflammatory processes. Its role in physiological and pathogenic processes throughout the human body has been the subject of numerous studies in recent years. Measurements of the IL-6 levels in gingival crevicular fluid (GFC), as well as in serum, can be important diagnostic and prognostic factors in periodontal diseases (PD) and in assessing their impact on a range of related inflammatory diseases. This narrative review explores the significant role of IL-6 in patients with periodontitis and its association with other widespread inflammatory pathologies.

The osteogenic effects of sappanchalcone in vitro and in vivo

BACKGROUND AND OBJECTIVES

The utilization of natural products to enhance the function of periodontal ligament cells (PDLCs) has emerged as a popular area of research. Recent investigations have demonstrated that sappanchalcone (SC) possesses pharmacological properties such as anti-inflammatory and osteoprotective effects. This study aims to explore the impact of SC on the in vivo and in vitro osteogenic differentiation ability of PDLCs.

MATERIALS

Cell proliferation was quantified using the CCK-8 assay, while gene expression levels were assessed through qRT-PCR analysis. Osteoblast differentiation capacity was evaluated by employing Alizarin red staining (ARS), alkaline phosphatase (ALP) staining and western blot (WB) analysis. A rat model of periodontitis was established utilizing the tether-wire method. Micro-CT imaging and hematoxylin and eosin (HE) staining were employed to evaluate alveolar bone resorption. Masson's trichrome staining was utilized to observe fiber alignment, whereas immunohistochemistry (IHC) techniques were applied for detecting osteogenic and inflammatory factors.

RESULTS

The results from the CCK-8 assay indicate no observed cytotoxicity for concentrations of 1, 5, or 10 nM for SC treatment (p < .05), while qRT-PCR analysis demonstrates a significant decrease in inflammatory factors such as MMP-1 and IL-6 with treatment by SC (p < .05). Additionally, western blotting reveals an increase in protein expression levels of Runx2 and OPN within PDLCs treated with SC compared to control groups (p < .05), which is further supported by ARS and ALP staining indicating an increase in mineralized nodules formation along with elevated ALP content within these cells following treatment with this compound (p < .05). Finally, both HE staining as well as micro-CT imaging suggest potential benefits associated with using this compound including slowing alveolar bone resorption while simultaneously promoting junctional epithelium proliferation.

CONCLUSIONS

Our in vitro and in vivo findings suggest that SC can effectively enhance the inflammatory response of PDLCs and promote their osteogenic differentiation ability under inflammatory conditions, indicating its potential as a promising therapeutic agent for improving periodontal inflammation and bone formation.

Salivary Interleukin-6 as a Non-Invasive Biomarker for Chronic Periodontitis and Tooth Loss in Type 2 Diabetes

BACKGROUND

Periodontitis and type 2 diabetes are chronic inflammatory diseases that increase inflammatory Interleukin-6 (IL-6) levels that induce the production of advanced glycation end products (AGEs) causing receptor activator of nuclear factor-kappa B ligand (RANKL) expression on osteoclasts, contributing to further alveolar bone destruction.

AIM

To assess the role and diagnostic potential of salivary IL-6 (SIL-6) in the detection and evaluation of chronic periodontitis (CP) and tooth loss in type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

This cross-sectional study comprised 240 subjects aged 30-69 years with minimum of 15 natural teeth. Fasting, unstimulated whole saliva was collected, full-mouth intra-oral examination and periodontal evaluation were performed using PCP-UNC 15 probe and glycaemic (HbA1c) levels were analysed by high-performance liquid chromatography (HPLC) method. Subjects were categorised into four groups of 60 participants each: Group 1 (controls); Group 2 (CP); Group 3 (T2DM with CP); Group 4 (T2DM with CP and tooth loss). Salivary IL-6 levels were quantitatively assessed by enzyme-linked immune sorbent assay method.

RESULTS

Average SIL-6 levels were significantly elevated in Group 4 (T2DM with CP and tooth loss) (P = 0.001) and in severe periodontitis (P = 0.001). Karl Pearson Correlation found a significant association between average SIL-6 and average periodontal pocket depth (APPD) (r = 0.180), average clinical attachment loss ≥3 mm (ACAL3) (r = 0.289) and severity of periodontitis (r = 0.3228). The receiver operating characteristic (ROC) curve depicted an overall sensitivity of 53.3%, specificity of 68.6% and accuracy of 60% in the detection and assessment of CP in T2DM with tooth loss.

CONCLUSION

IL-6 in saliva is a valuable, non-invasive biomarker in the detection and evaluation of CP in T2DM with tooth loss.

Photodynamic therapy in periodontitis: A narrative review

BACKGROUND

Periodontitis, a chronic infectious disease, is primarily caused by a dysbiotic microbiome, leading to the destruction of tooth-supporting tissues and tooth loss. Photodynamic therapy (PDT), which combines excitation light with photosensitizers (PS) and oxygen to produce antibacterial reactive oxygen species, is emerging as a promising adjuvant treatment for periodontitis.

METHODS

This review focuses on studies examining the antibacterial effects of PDT against periodontal pathogens. It also explores the impact of PDT on various aspects of periodontal health, including periodontal immune cells, human gingival fibroblasts, gingival collagen, inflammatory mediators, cytokines in the periodontium, vascular oxidative stress, vascular behavior, and alveolar bone health. Clinical trials assessing the types of PSs and light sources used in PDT, as well as its effects on clinical and immune factors in gingival sulcus fluid and the bacterial composition of dental plaque, are discussed.

RESULTS

The findings indicate that PDT is effective in reducing periodontal pathogens and improving markers of periodontal health. It has shown positive impacts on periodontal immune response, tissue integrity, and alveolar bone preservation. Clinical trials have demonstrated improvements in periodontal health and alterations in the microbial composition of dental plaque when PDT is used alongside conventional treatments.

CONCLUSIONS

PDT offers a promising adjunctive treatment for periodontitis, with benefits in bacterial reduction, tissue healing, and immune modulation. This article highlights the potential of PDT in periodontal therapy and emphasizes the need for further research to refine its clinical application and efficacy.

METTL3 and METTL14 regulate IL-6 expression via RNA m6A modification of zinc transporter SLC39A9 and DNA methylation of IL-6 in periodontal ligament cells

The inflammatory response is a key process in periodontitis. The N6-methyladenosine (m6A) modification has been proven to be involved in various physiological and pathological processes. This study aims to investigate the role and downstream mechanism of N6-adenosine-enzyme subunits methyltransferase (METTL) 3 and 14 in the inflammatory response of periodontal ligament cells (PDLCs). The total m6A content and the expression of METTL3 and METTL14 were upregulated in lipopolysaccharide (LPS)-stimulated PDLCs. Knockdown of METTL3 or METTL14 suppressed the LPS-induced interleukin (IL)-6 expression, as shown by quantitative polymerase chain reaction (qPCR) and enzyme linked immunosorbent assay (ELISA). Mechanistically, conjoint analysis of m6A sequencing of METTL3-knockdown and METTL14-knockdown PDLCs revealed that the expression of solute carrier family 39 member 9 (SLC39A9) was mediated in a m6A-dependent manner. The suppression of LPS-induced IL-6 by METTL3 or METTL14 knockdown was partially counteracted by SLC39A9 knockdown, which induced downregulation of intracellular zinc via immunofluorescence staining. Amplicon bisulfite sequencing (AmpBS) demonstrated that METTL3/14 knockdown increased the methylation at one position of the IL-6 promoter, while SLC39A9 knockdown decreased it, which was basically consistent with the intracellular zinc concentration and negatively associated with IL-6 expression. Moreover, METTL3 or METTL14 knockdown attenuated the LPS-induced phosphorylation of p38 and JNK mitogen-activated protein kinase (MAPK), which was partially counteracted by SLC39A9 knockdown. These results revealed the "LPS-METTL3/14-SLC39A9-zinc-IL-6" axis and involvement of p38 and JNK MAPK signaling pathway in the inflammatory responses of PDLCs.

An evaluation of photobiomodulation effects on human gingival fibroblast cells under hyperglycemic condition: an in vitro study

An in vitro study was designed to evaluate the effects of photobiomodulation (PBM) with 915-nm diode laser on human gingival fibroblast (HGF) cells under hyperglycemic condition. The HGF cells were cultured in Dulbecco's modified eagle medium (DMEM) medium containing 30 mM glucose concentration for 48 h to mimic the hyperglycemic condition. Subsequently, the cells received three sessions of PBM (915 nm, continuous emission mode, 200 mW, energy density values of 3.2, 6, and 9.2 J/cm2). Twenty-four hours post-irradiation, cell proliferation, expression of interleukin 6 (IL-6), and vascular endothelial growth factor (VEGF) were assessed with MTT and real-time polymerase chain reaction (PCR) tests, respectively. Also, reactive oxygen species (ROS) production was measured using CM-H2DCFDA fluorimetry. No changes were detected in the cell proliferation rate between the high glucose control group and laser-treated cells, while VEGF and IL-6 gene expression levels increased significantly after PBM in the high glucose-treated cells group. ROS level was significantly decreased in the irradiated cells in high-glucose medium compared with the high glucose control group. Our study revealed the inductive role of 915-nm-mediated PBM on VEGF and the inflammatory response while concurrently reducing reactive oxygen species production in HGF cells in hyperglycemic conditions.

Proteomic and single-cell analysis shed new light on the anti-inflammatory role of interferonβ in chronic periodontitis

Periodontitis, a condition that results in periodontal attachment loss and alveolar bone resorption, contributes to the global burden of oral disease. The underlying mechanism of periodontitis involves the dysbiosis and dyshomeostasis between host and oral microbes, among which the macrophage is one of the major innate immune cell players, producing interferon β (IFNβ) in response to bacterial infection. The objective of this research was to examine the interaction of macrophages with periodontitis and the role and mechanism of IFNβ on macrophages. IFNβ has been shown to have the potential to induce the differentiation of M1 to M2 macrophages, which are stimulated by low levels of lipopolysaccharide (LPS). Additionally, IFNβ has been demonstrated to promote the production of ISG15 by macrophages, which leads to the inhibition of the innate immune response. Moreover, our investigation revealed that IFNβ has the potential to augment the secretion of ISG15 and its downstream cytokine, IL10, in LPS-stimulated macrophages. Single-cell analysis was conducted on the gingival tissues of patients with periodontitis, which revealed a higher proportion of macrophages in the periodontitis-diseased tissue and increased expression of IFNβ, ISG15, and IL10. Gene Set Enrichment Analysis indicated that bacterial infection was associated with upregulation of IFNβ, ISG15, and IL10. Notably, only IL10 has been linked to immunosuppression, indicating that the IFNβ-ISG15-IL10 axis might promote an anti-inflammatory response in periodontitis through IL10 expression. It is also found that macrophage phenotype transitions in periodontitis involve the release of higher levels of IFNβ, ISG15, and IL10 by the anti-inflammatory M2 macrophage phenotype compared to the pro-inflammatory M1 phenotype and myeloid-derived suppressor cells (MDSCs). This implies that the IFNβ-induced production of IL10 might be linked to the M2 macrophage phenotype. Furthermore, cell communication analysis demonstrated that IL10 can promote fibroblast proliferation in periodontal tissues via STAT3 signaling.

Effect of non-surgical periodontal treatment on cytokines/adipocytokines levels among periodontitis patients with or without obesity: a systematic review and meta-analysis

BACKGROUND

The objective of this systematic review and meta-analysis was to evaluate the effects of non-surgical periodontal therapy (NSPT) on inflammatory-related cytokines/adipocytokines in periodontitis patients with or without obesity.

METHODS

We followed the preferred reporting items for systematic reviews and meta-analyses statement and registered the study (CRD42022375331) in the Prospective International Register of Systematic Reviews. We screened randomized-controlled trials and controlled clinical trials from six databases up to December 2022. Quality assessment was performed with RoB-2 and ROBINS-I tools for randomized trials and non-randomized trials, respectively. Meta-analysis was carried out using a random-effect model.

RESULTS

We included seventeen references in the systematic analysis, and sixteen in the meta-analysis. Baseline results of pro-inflammatory biomarkers, including serum interleukin (IL)-6, serum and gingival crevicular fluid (GCF), tumor necrosis factor (TNF)-a, serum C-reactive protein (CRP)/hs-CRP, and serum and GCF resistin, were higher in obesity subjects than in normal weight subjects. The effect of NSPT with respect to levels of cytokines/adipocytokines, including IL-6, TNF-a, CRP/hs-CRP, resistin, adiponectin, leptin and retinol binding protein 4 (RBP4), were then analyzed in the systematic and meta-analysis. After three months of NSPT, serum (MD = -0.54, CI = -0.62 - -0.46), and GCF (MD = -2.70, CI = -4.77 - -0.63) levels of IL-6, along with the serum RBP4 (MD = -0.39, CI = -0.68-0.10) decreased in periodontitis individuals with obesity. NSPT also improved GCF adiponectin levels after three months (MD = 2.37, CI = 0.29 - 4.45) in periodontitis individuals without obesity.

CONCLUSIONS

Obese status altered the baseline levels of cytokines/adipocytokines (serum IL-6, serum and GCF TNF-a, serum CRP/hs-CRP, and serum and GCF resistin). Then NSPT can shift the levels of specific pro-inflammatory mediators and anti-inflammatory mediators in biological fluids, both in obesity and non-obesity individuals. NSPT can reduce serum and GCF IL-6 levels together with serum RBP4 level in individuals with obesity after 3 months, besides, there is no sufficient evidence to prove that obese patients have a statistically significant decrease in the levels of other cytokines compared to patients with normal weight. NSPT can also increase GCF adiponectin level in normal weight individuals after 3 months. Our findings imply the potential ideal follow-up intervals and sensitive biomarkers for clinical bioanalysis in personalized decision-making of effect of NSPT due to patients' BMI value.

Critical roles of PU.1/cathepsin S activation in regulating inflammatory responses of macrophages in periodontitis

OBJECTIVE

To determine the critical roles of PU.1/cathepsin S activation in regulating inflammatory responses of macrophages during periodontitis.

BACKGROUND

Cathepsin S (CatS) is a cysteine protease and exerts important roles in the immune response. Elevated CatS has been found in the gingival tissues of periodontitis patients and is involved in alveolar bone destruction. However, the underlying mechanism of CatS-driven IL-6 production in periodontitis remains unclear.

METHODS

Western blot was applied to measure mature cathepsin S(mCatS) and IL-6 expression in gingival tissues from periodontitis patients and RAW264.7 cells exposed to lipopolysaccharide from Porphyromonas gingivalis (P.g. LPS). Immunofluorescence was applied to confirm the localization of PU.1, and CatS in the gingival tissues of periodontitis patients. ELISA was performed to determine IL-6 production by the P.g. LPS-exposed RAW264.7 cells. Knockdown by shRNA was used to determine the effects of PU.1 on p38/ nuclear factor (NF)-κB activation, mCatS expression and IL-6 production in RAW264.7 cells.

RESULTS

The expressions mCatS and IL-6 were significantly upregulated in gingival macrophages. In cultured RAW264.7 cells, increased mCatS and IL-6 protein paralleled the activation of p38 and NF-κB after exposure to P.g. LPS. CatS knockdown by shRNA significantly decreased P.g. LPS-induced IL-6 expression and p38/NF-κB activation. PU.1 was significantly increased in P.g. LPS-exposed RAW264.7 cells, and PU.1 knockdown dramatically abolished the P.g. LPS-induced upregulation of mCatS and IL-6 and the activation of p38 and NF-κB. Furthermore, PU.1 and CatS colocalized in macrophages within the gingival tissues of periodontitis patients.

CONCLUSION

PU.1-dependent CatS drives IL-6 production in macrophages by activating p38 and NF-κB in periodontitis.

Inhibition of gingival fibroblast necroptosis mediated by RIPK3/MLKL attenuates periodontitis

AIM

Necroptosis participates in the pathogenesis of many inflammatory diseases, including periodontitis. Here, we aimed to investigate the role and mechanism of necroptosis inhibitors in attenuating periodontitis.

MATERIALS AND METHODS

The Gene Expression Omnibus (GEO) dataset GSE164241 was re-analysed to identify the role of necroptosis in periodontitis. Gingival specimens from healthy subjects or periodontitis patients were collected to evaluate the expression level of necroptosis-associated proteins. The therapeutic effect of necroptosis inhibitors on periodontitis was assessed in vivo and in vitro. Moreover, Transwell assays and Western blotting and siRNA transfection were used to identify the effects of necroptotic human gingival fibroblasts (hGFs) on THP-1 macrophages.

RESULTS

Re-analysis revealed that gingival fibroblasts (GFs) in periodontitis gingiva showed the highest area under the curve score of necroptosis. Elevated levels of necroptosis-associated proteins were identified in GFs in periodontitis gingiva collected from patients and mice. In ligature-induced periodontitis mice, local administration of receptor interacting protein kinase 3(RIPK3) inhibitor GSK'872 or sh-mixed-lineage kinase domain-like pseudokinase (Mlkl) markedly abrogated necroptosis and rescued periodontitis. Analogously, necroptosis inhibitors alleviated the inflammatory response and release of damage-associated molecular patterns in lipopolysaccharide- or LAZ (LPS + AZD'5582 + z-VAD-fmk, necroptosis inducer)-induced GFs and then reduced THP-1 cell migration and M1 polarization.

CONCLUSIONS

Necroptosis in GFs aggravated gingival inflammation and alveolar bone loss. Necroptosis inhibitors attenuate this process by modulating THP-1 macrophage migration and polarization. This study offers novel insights into the pathogenesis and potential therapeutic targets of periodontitis.

A physiologically relevant culture platform for long-term studies of in vitro gingival tissue

There is a clinical need to understand the etiologies of periodontitis, considering the growing socio-economic impact of the disease. Despite recent advances in oral tissue engineering, experimental approaches have failed to develop a physiologically relevant gingival model that combines tissue organization with salivary flow dynamics and stimulation of the shedding and non-shedding oral surfaces. Herein, we develop a dynamic gingival tissue model composed of a silk scaffold, replicating the cyto-architecture and oxygen profile of the human gingiva, along with a saliva-mimicking medium that reflected the ionic composition, viscosity, and non-Newtonian behavior of human saliva. The construct was cultured in a custom designed bioreactor, in which force profiles on the gingival epithelium were modulated through analysis of inlet position, velocity and vorticity to replicate the physiological shear stress of salivary flow. The gingival bioreactor supported the long-term in vivo features of the gingiva and improved the integrity of the epithelial barrier, critical against the invasion of pathogenic bacteria. Furthermore, the challenge of the gingival tissue with P. gingivalis lipopolysaccharide, as an in vitro surrogate for microbial interactions, indicated a greater stability of the dynamic model in maintaining tissue homeostasis and, thus, its applicability in long-term studies. The model will be integrated into future studies with the human subgingival microbiome to investigate host-pathogen and host-commensal interactions. STATEMENT OF SIGNIFICANCE: The major societal impact of human microbiome had reverberated up to the establishment of the Common Fund's Human Microbiome Project, that has the intent of studying the role of microbial communities in human health and diseases, including periodontitis, atopic dermatitis, or asthma and inflammatory bowel disease. In addition, these chronic diseases are emergent drivers of global socioeconomic status. Not only common oral diseases have been shown to be directly correlated with several systemic conditions, but they are differentially impacting some racial/ethnic and socioeconomic groups. To address this growing social disparity, the development of in vitro gingival model would provide a time and cost-effective experimental platform, able to mimic the spectrum of periodontal disease presentation, for the identification of predictive biomarkers for early-stage diagnosis.

O-GlcNAcylation of NLRP3 Contributes to Lipopolysaccharide-Induced Pyroptosis of Human Gingival Fibroblasts

Periodontitis is a leading chronic oral disorder and poses a serious burden on public health. O-GlcNAc glycosylation (O-GlcNAcylation) is regulated only by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) and participates in the regulation of human gingival fibroblasts (HGFs) function. Hence, the purpose of this study is to investigate whether HGFs cell function and periodontitis pathogenesis are regulated by O-GlcNAcylation. Herein, we first established cell model of periodontitis induced by lipopolysaccharide (LPS). The cell viability was measured with CCK-8 assay. Pyroptosis was measured by flow cytometry and western blot. The inflammatory factors levels were detected with ELISA kits. Afterward, our findings indicated that LPS elevated the O-GlcNAcylation level of HGFs and inhibition of O-GlcNAcylation improved LPS-induced pyroptosis of HGFs. Mechanistically, LPS heightened the expression of OGT to induce the O-GlcNAcylation of NLRP3. Subsequently, we certified that Thr542 was the O-GlcNAcylation site of NLRP3. More importantly, upregulation of NLRP3 reversed the effects of OGT knockdown on LPS-induced pyroptosis. In general, the current research demonstrated that LPS contributed to the pyroptosis of HGFs by enhancing the OGT expression to promote O-GlcNAcylation of NLRP3, which suggested that O-GlcNAcylation of NLRP3 was a driving factor for periodontitis and offered a novel insight into the treatment of this disease.

Inhibitory Effects of Corydalis saxicola Bunting Total Alkaloids on Macrophage Pyroptosis

This study investigated the effect of Corydalis saxicola Bunting total alkaloids (CSBTA) on pyroptosis in macrophages (Mϕ). In the Mϕ pyroptosis model, an inverted fluorescence microscope was used to assess cell pyroptosis, while a scanning electron microscope was used to observe morphological changes in Mϕ. NLR family pyrin domain-containing 3 (NLRP3), caspase-1, and gasdermin D (GSDMD) expression levels were detected by polymerase chain reaction and western blotting, whereas interleukin-1 (IL-1) and interleukin-18 (IL-18) expression levels were measured by an enzyme-linked immunosorbent assay. After pretreatment with CSBTA or the caspase-1 inhibitor, acetyl-tyrosyl-valyl-alanyl-aspartyl-chloromethylketone (Ac-YVAD-cmk), it was discovered that NLRP3, caspase-1, and GSDMD expressions were significantly reduced at both the mRNA and protein levels, as were IL-1 and IL-18 levels. The inhibitory effects of CSBTA and Ac-YVAD-cmk did not differ significantly. These findings indicate that CSBTA blocks Porphyromonas gingivalis-lipopolysaccharide-induced Mϕ pyroptosis.

Association between an Anti-Inflammatory Dietary Score and Periodontitis-Evidence from the Population-Based Hamburg City Health Study

While the effects of dietary patterns on cardiovascular risk and diabetes have been well studied, the evidence is scarce as to which diet has the greatest anti-inflammatory potential and how dietary patterns are associated with periodontitis. In the Hamburg City Health Study (HCHS), we developed an anti-inflammatory dietary score using a data-driven approach based on the relationship of relevant selected food groups with inflammatory biomarkers (hsCRP and IL-6). The aim of this cross-sectional study was to evaluate the association between the anti-inflammatory dietary score and the incidence of periodontitis in Hamburg, Germany. A total of n = 5642 participants fit the required inclusion criteria and were selected for analysis. Periodontal disease was assessed using probing depth, gingival recession, and bleeding on probing. Dietary intake was measured using a food frequency questionnaire (FFQ). A self-developed anti-inflammatory dietary score served as the key explanatory variable. Higher scores reflected lower inflammatory processes (measured through the biomarkers hsCRP and IL-6). Several covariates were included in the regression analysis. Regressions revealed that a higher anti-inflammatory dietary score was significantly associated with lower odds to be affected by periodontal disease in an unadjusted model (OR 0.86, 95% CI 0.82-0.89, p < 0.001) and in an adjusted model (age, sex, smoking, diabetes, hypertension, and physical activity) (OR 0.93, 95% CI 0.89-0.98, p = 0.003). Our study demonstrated a significant inverse association between an anti-inflammatory dietary score and periodontitis. Individuals with higher intake of proinflammatory nutrition should be specifically addressed to avoid periodontitis.

Silibinin alleviates inflammation-induced bone loss by modulating biological interaction between human gingival fibroblasts and monocytes

BACKGROUND

Silibinin has shown various pharmacological effects that could be attributed to its antioxidant, anti-inflammatory, and immunoregulatory properties. However, the therapeutic potential of silibinin for periodontitis has not been investigated.

METHODS

The therapeutic effects of silibinin in ligation-induced experimental periodontitis were investigated using biochemical, histological, and immunohistochemical methods. The effects of silibinin on the osteoclastogenesis of RAW264.7 cells were investigated using TRAP staining, quantitative polymerase chain reaction (qPCR), pit formation, and immunoblotting. Moreover, its effects on inflammatory cytokine production, RANKL expression, and oxidative stress in lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (HGFs) were evaluated using qPCR and flow cytometry. A coculture system was established to elucidate the effects of silibinin on the crosstalk between LPS-stimulated HGFs and undifferentiated monocytes.

RESULTS

Silibinin significantly reduced the alveolar bone loss, decreased the gingival inflammation and RANKL expression, and decreased the RANKL/osteoprotegerin ratio in gingival tissues in experimental periodontitis. The in vitro results showed that silibinin inhibited RANKL-induced osteoclast differentiation and function of RAW264.7 cells and suppressed RANKL-induced nuclear factor of activated T cells 1 (NFATc1) induction and translocation through the nuclear factor-κB and mitogen-activated protein kinase signaling pathways. Silibinin decreased the inflammatory cytokine level and oxidative stress production in LPS-stimulated HGFs; significantly suppressed membrane-bound RANKL expression on LPS-stimulated HGFs; and significantly disrupted TRAP+ cell differentiation in the coculture system.

CONCLUSIONS

Silibinin effectively inhibits inflammation-induced bone loss in experimental periodontitis based on the regulation of stimulated HGFs by inhibiting the expression of inflammatory and osteoclastogenic mediators. Collectively, targeting the inflamed HGF resolution that mediates osteogenesis may use silibinin as a potential drug-repurposing candidate for modulating alveolar bone destruction in periodontitis.

SUMMARY

Silibinin effectively inhibits inflammation-induced bone loss in experimental periodontitis based on the regulation of stimulated HGFs by inhibiting the expression of inflammatory and osteoclastogenic mediators.

Metabolic reprogramming through mitochondrial biogenesis drives adenosine anti-inflammatory effects: new mechanism controlling gingival fibroblast hyper-inflammatory state

Introduction

Fibroblasts are the dominant stromal cells in the gingival lamina propria with a well-established relevance in regulation of inflammation, and in innate immunity. This is exemplified by their hypersecretion of CXCL8, enhancing leukocyte infiltration in chronic and sustained inflammatory conditions. We have previously shown adenosine to be a key metabolic nucleoside that regulates stromal inflammation, but the underlying mechanisms linking adenosine to the metabolic status of fibroblasts and to the resultant inflammatory response are unclear. This study examined, by seahorse real-time cell metabolic analysis, the bioenergetics of the stromal fibroblast response to extracellular adenosine and IL-1β, focusing on CXCL8 secretion by primary human gingival fibroblasts (HGF).

Methods

Markers of the glycolytic pathway and mitochondrial biogenesis were tracked through immunoblot. Further, the influence of adenosine on mitochondrial accumulation was measured by uptake of MitoTracker Red fluorescent probe and assessment of the role of FCCP (a mitochondrial uncoupler) in CXCL8 secretion and mitochondrial accumulation.

Results

Our results show that the anti-inflammatory response of HGF to extracellular adenosine, typified by reduced CXCL8 secretion, is mediated by mitochondrial oxidative phosphorylation, reflected in higher oxygen consumption rate (OCR). In the presence of IL-1β, adenosine-treated cells induced higher ATP production, basal respiration and proton leak compared to IL-1β without adenosine. Surprisingly, adenosine had no additional effect on the IL-1β-induced higher glycolysis rate demonstrated by the extracellular acidification rate (ECAR). In addition, the higher OCR in adenosine-stimulated cells was not due to the mitochondrial fuel dependency or capacity, but due to an increase in mitochondrial biogenesis and accumulation in the cells with concomitant decrease in mitophagy-required p-PINK1 marker. We detected the accumulation of functional mitochondria with increased activation of the AMPK/SIRT1/PGC-1α pathway. The adenosine-induced uptake of MitoTracker was abrogated by PGC-1α inhibition with SR-12898. In addition, the adenosine effects on reduced CXCL8 were ablated by treatment with FCCP, a potent uncoupler of mitochondrial oxidative phosphorylation.

Conclusion

Our findings reveal a key role for mitochondrial bioenergetics in regulation of CXCL8-mediated inflammation by HGF through the adenosine/AMPK/SIRT1/PGC-1α axis. Therapeutically targeting this pathway in gingival fibroblasts might be a promising future strategy to modulate stromal-mediated sustained hyper-inflammatory responses.

Downregulation of interleukin 6 signaling might reduce the risk of periodontitis: a drug target Mendelian randomization study

Aim

Interleukin 6 (IL-6) is considered to play a role in the dysbiotic host response in the development of periodontitis. While the inhibition of the IL-6 receptor using monoclonal antibodies is a well-established therapy for some diseases, so far, its potential benefit in patients with periodontitis has not been examined. We tested the association of genetically proxied downregulation of IL-6 signaling with periodontitis to explore whether downregulation of IL-6 signaling could represent a viable treatment target for periodontitis.

Materials and methods

As proxies for IL-6 signaling downregulation, we selected 52 genetic variants in close vicinity of the gene encoding IL-6 receptor that were associated with lower circulating C-reactive protein (CRP) levels in a genome-wide association study (GWAS) of 575 531 participants of European ancestry from the UK Biobank and the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium. Associations with periodontitis were tested with inverse-variance weighted Mendelian randomization in a study of 17 353 cases and 28 210 controls of European descent in the Gene-Lifestyle Interactions in Dental Endpoints (GLIDE) consortium. In addition, the effect of CRP reduction independent of the IL-6 pathway was assessed.

Results

Genetically proxied downregulation of IL-6 signaling was associated with lower odds of periodontitis (odds ratio (OR) = 0.81 per 1-unit decrement in log-CRP levels; 95% confidence interval (CI): [0.66;0.99]; P = 0.0497). Genetically proxied reduction of CRP independent of the IL-6 pathway had a similar effect (OR = 0.81; 95% CI: [0.68; 0.98]; P = 0.0296).

Conclusion

In conclusion, genetically proxied downregulation of IL-6 signaling was associated with lower odds of periodontitis and CRP might be a causal target for the effect of IL-6 on the risk of periodontitis.

Current Molecular, Cellular and Genetic Aspects of Peri-Implantitis Disease: A Narrative Review

(1) Background: Peri-implantitis is a multi-factorial disease with an inflammatory background that occurs in both soft and hard tissues surrounding implants. In recent years, the understanding of the cellular, molecular and genetic background of peri-implantitis has broadened. This study aims to summarize the currently available articles on the subject and highlight the most recent advances over the last 20 years. (2) Methods: For this study, the Embase and PubMed libraries were searched using the keywords: ("peri-implantitis" AND "cytokine" OR "genetics" OR "cellular") and ("peri-implantitis" AND "cytokine" OR "genetics" OR "cellular" AND "risk factors"). The search revealed a total of 3013 articles (992 from PubMed, 2021 from Embase). Following screening of the titles and abstracts and full-text reads, 55 articles were included. (3) Results: In peri-implantitis IL-6, IL-1β, TNF-α, MMP-8 and their genetic variations appear to be the most important cytokines in relation to not only pathogenesis, but also their potential diagnostic capabilities. Epithelial and inflammatory cells, along with those of the bone lineage, are prime cellular elements found in peri-implantitis. (4) Conclusions: A wide array of cells stand behind peri-implantitis, as well as cytokines and their genetic variations that take part in the process. However, the growing interest in this topic has led to the introduction of specific new diagnostic tools to enable a better understanding of patients' responses to treatment and, in turn, to even enable prediction of the risk of developing peri-implant disease.

Analysis of the Effects of IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C Gene Polymorphisms; IL-6 Levels; and CRP Levels on Chronic Periodontitis in Coronary Artery Disease in Indonesia

Interleukin 6 (IL-6) and C-Reactive Protein (CRP) play an important role in chronic periodontitis with coronary artery disease (CAD). Genetic factors can affect a person's risk of CAD, which affects one-third of the population. This study investigated the role of IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C gene polymorphisms. IL-6 and CRP levels on the severity of periodontitis in CAD in Indonesia were also evaluated. This case-control study was conducted with mild and moderate-severe chronic periodontitis groups. A path analysis test was conducted with Smart PLS with a 95% confidence interval to determine the significant variable for chronic periodontitis. Our study revealed that the effects of IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C gene polymorphisms on IL-6 levels and CRP levels were not significant. IL-6 and CRP levels were not significantly different between the two groups. We found that IL-6 levels had a significant effect on CRP levels in periodontitis patients with CAD (path coefficient 0.322, p = 0.003). IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C gene polymorphisms had no effect on the severity of chronic periodontitis in CAD patients in the Indonesian population. We also observed no apparent effects of the influence of gene polymorphisms in IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C genes. Although the IL-6 and CRP levels were not significantly different between the two groups, IL-6 levels affected CRP levels in periodontitis patients with CAD.

Qinteng Tongbi Decoction Medicated Serum Exerts Regulates the Proliferation, Migration, and Apoptosis of Synovial Fibroblasts in Adjuvant-Induced Arthritis Rats Model via Phosphatidylinositol 3-Kinase/Protein Kinase B Signaling Pathway

Background

Qinteng Tongbi decoction (QTTBD) was an empirical prescription that could effectively prevent and treat rheumatoid arthritis (RA), but there was no report of pharmacological studies on this prescription. The purpose of this paper was to report the effects of QTTBD on the proliferation, migration, and apoptosis of synovial fibroblasts in adjuvant arthritis model rats, and to reveal its anti-RA regulatory mechanism.

Methods

To divide the fibroblast-like synovial (FLS) cells of experimental rats into 6 groups (blank control group, model control group, positive drug group, QTTBD high, medium, and low dose groups) and cultured with serum-containing drugs. And using Cell Counting Kit-8 to detect the proliferation rate of FLS cells, flow cytometry to detect the apoptosis of FLS cells, the enzyme-linked immunosorbent assay method to detect the levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α), Western Blot to detect phosphatidylinositol 3-kinase (PI3K), AKT1, p-AKT1, Bax and Bcl-2 gene and protein expression.

Results

Experimental results showed that QTTBD-containing serum could effectively inhibit the proliferation of FLS cells ( p <0 .05), induce the apoptosis of FLS cells, reduce the expression levels of inflammatory factors such as IL-6, IL-1β, and TNF-α ( p <0 .05), reduce expression of PI3K, AKT1, p-AKT1, and Bax ( p <0 .05), while the Bcl-2 expression increased ( p <0 .05).

Conclusion

QTTBD could effectively regulate the proliferation, migration, and apoptosis of FLS cells in adjuvant-induced arthritis (AIA) rats, and its mechanism might be related to regulating the level of inflammatory factors and intervening in the PI3K/protein kinase B (AKT) signaling pathway.

Oxidative stress in human gingival fibroblasts from periodontitis versus healthy counterparts

OBJECTIVE

Elevated p53 promotes oxidative stress and production of pro-inflammatory cytokines in liposaccharide (LPS)-treated healthy human gingival fibroblasts (HGFs). This study compared oxidative stress, production of inflammatory cytokines, and p53 expression in HGFs from patients with chronic periodontitis (CP) and healthy subjects in vitro upon LPS from Porphyromonas gingivalis challenge.

METHODS

Human gingival fibroblasts were isolated from 6 biopsies-3 from healthy donors and 3 from diseased area in CP (Grade B, Stage III). HGFs were cultured with or without 1 μg/ml 24 h LPS. Oxidative stress was assessed by analyzing the level of reactive oxygen species (ROS). Mitochondrial membrane potential and respiration were determined by immunofluorescence and respirometry, respectively. Tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β were determined by enzyme-linked immunosorbent assay. P53 expression was monitored by Western blot and immunofluorescence.

RESULTS

Human gingival fibroblasts from CP exhibited increased levels of mitochondrial p53, enhanced ROS production, decreased mitochondrial membrane potential, increased mitochondrial oxygen consumption, and increased secretion of TNF-α, IL-6, and IL-1β, as compared to HGFs from healthy donors. Moreover, LPS exacerbated these changes.

CONCLUSION

Human gingival fibroblasts from CP exhibited stronger basal and LPS-inducible oxidative stress and inflammatory response as compared to HGFs from healthy subjects by increased p53 in mitochondria.

Controlled Cascade-Release and High Selective Sterilization by Core-Shell Nanogels for Microenvironment Regulation of Aerobic Vaginitis

Aerobic vaginitis (AV) is a gynecological disease associated with vaginal flora imbalance. The nonselective bactericidal nature of antibiotics and low customization rate of probiotic supplementation in existing treatments lead to AV recurrence. Here, a drug delivery strategy is proposed that works with the changing dynamics of the bacterial flora. In particular, a core-shell nanogel (CSNG) is designed to encapsulate prebiotic inulin and antimicrobial peptide Cath 30. The proposed strategy allows for the sequential release of both drugs using gelatinase produced by AV pathogenic bacteria, initially selectively killing pathogenic bacteria and subsequently promoting the proliferation of beneficial bacteria in the vagina. In a simulated infection environment in vitro, the outer layer of CSNGs, Cath 30 is rapidly degraded and potently killed the pathogenic bacterium Staphylococcus aureus at 2-6 h. CSNGs enhances proliferation of the beneficial bacterium Lactobacillus crispatus by more than 50% at 24 h. In a rat AV model, the drug delivery strategy precisely regulated the bacterial microenvironment while controlling the inflammatory response of the vaginal microenvironment. This new treatment approach, configured on demand and precisely controlled, offers a new strategy for the treatment of vaginal diseases.

Potential Impact of Prosthetic Biomaterials on the Periodontium: A Comprehensive Review

The success of a prosthetic treatment is closely related to the periodontal health of the individual. The aim of this article was to review and present the importance of prosthetic restorative materials on the condition of the periodontium, the changes that occur in the composition of the subgingival microbiota and the levels of inflammatory markers in gingival crevicular fluid. Articles on the influence of different prosthetic restorative materials on subgingival microbiota and proinflammatory cytokines were searched for using the keywords "prosthetic biomaterials", "fixed prosthesis", "periodontal health", "subgingival microbiota", "periodontal biomarkers" and "gingival crevicular fluid" in PubMed/Medline, Science Direct, Scopus and Google Scholar. The type of material used for prosthesis fabrication together with poor marginal and internal fit can result in changes in the composition of the subgingival microbiota, as well as increased accumulation and retention of dentobacterial plaque, thus favoring the development of periodontal disease and prosthetic treatment failure. Biological markers have helped to understand the inflammatory response of different prosthetic materials on periodontal tissues with the main purpose of improving their clinical application in patients who need them. Metal-free ceramic prostheses induce a lower inflammatory response regardless of the fabrication method; however, the use of CAD/CAM systems is recommended for their fabrication. In addition, it is presumed that metal-ceramic prostheses cause changes in the composition of the subgingival microbiota producing a more dysbiotic biofilm with a higher prevalence of periodontopathogenic bacteria, which may further favor periodontal deterioration.

Sema3A Drives Alternative Macrophage Activation in the Resolution of Periodontitis via PI3K/AKT/mTOR Signaling

Macrophages actively participate in immunomodulatory processes throughout periodontal inflammation. Regulation of M1/M2 polarization affects macrophage chemokine and cytokine secretion, resulting in a distinct immunological status that influences prognosis. Semaphorin 3A (Sema3A), a neurite growth factor, exerts anti-inflammatory effects. In this study, we investigated the immunomodulation of Sema3A on macrophage-related immune responses in vivo and in vitro. Topical medications of Sema3A in mice with periodontitis alleviated inflammatory cell infiltration into gingival tissue and reduced areas with positive IL-6 and TNFα expression. We observed that the positive area with the M2 macrophage marker CD206 increased and that of the M1 macrophage marker iNOS decreased in Sema3A-treated mice. It has been postulated that Sema3A alleviates periodontitis by regulating alternative macrophage activation. To understand the mechanism underlying Sema3A modulation of macrophage polarization, an in vitro macrophage research model was established with RAW264.7 cells, and we demonstrated that Sema3A promotes LPS/IFNγ-induced M1 macrophages to polarize into M2 macrophages and activates the PI3K/AKT/mTOR signaling pathways. Inhibition of the PI3K signaling pathway activation might reduce anti-inflammatory activity and boost the expression of the inflammatory cytokines, iNOS, IL-12, TNFα, and IL-6. This study indicated that Sema3A might be a feasible drug to regulate alternative macrophage activation in the inflammatory response and thus alleviate periodontitis.

Cl-amidine attenuates lipopolysaccharide-induced inflammation in human gingival fibroblasts via the JNK/MAPK, NF-κB, and Nrf2 signalling pathways

Cl-amidine has been reported to have anti-inflammatory properties in a variety of diseases. However, the role of Cl-amidine in periodontal disease remains unclear. Here, the purpose of this study was to investigate the effect of Cl-amidine on lipopolysaccharide (LPS)-induced inflammation in human gingival fibroblasts (HGFs). The cytotoxic effect of Cl-amidine was measured with the Cell Counting Kit-8 (CCK-8) assay and Annexin V-FITC/PI staining. The protein levels of IL-6 and IL-8 in culture supernatants were measured with enzyme-linked immunosorbent assay (ELISA). The mRNA levels of inflammatory cytokines, TLR4 and MyD88 were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The expression patterns of IL-6, TNF-ɑ, and IL-1β in HGFs were tested with western blot. The levels of NF-κB, MAPK, and Nrf2 pathway-related proteins were detected by western blot. Immunofluorescence (IF) staining was used to examine the nuclear translocation of NF-κB p65. Moreover, a rat gingivitis model was established to further clarify the role of Cl-amidine. Our results showed that Cl-amidine suppressed LPS-induced gingival inflammation both in vitro and in vivo. Mechanistically, Cl-amidine inhibited LPS-induced MyD88 expression, NF-κB activation, and JNK phosphorylation. Additionally, Cl-amidine upregulated Nrf2 and Ho-1 expression both with and without LPS stimulation but did not alter ROS levels or Keap1 expression. Overall, our data suggest that Cl-amidine acts as an inhibitor of LPS-induced gingival inflammation via the JNK/MAPK, NF-κB, and Nrf2 signalling pathways.

Fibroblast ferroptosis is involved in periodontitis-induced tissue damage and bone loss

Periodontitis causes inflammatory destructions of tooth-supporting tissue and constitutes a significant burden on public health. Failing to reserve the tissue damage and bone loss by any of the currently available therapies has left periodontitis uncurable thus far. Understanding the molecular mechanism in the inflammatory process is crucial to elucidating the pathogenesis and enlightening new therapeutic strategies for periodontitis. This study was to investigate whether and how ferroptosis, a newly-discovered form of cell death, was involved in the pathogenesis of periodontitis. Healthy and periodontitis human gingiva samples were collected and ligature-induced periodontitis murine models were constructed to investigate the role of ferroptosis in periodontitis. Single-cell RNA sequencing data was analyzed to identify the cell type that underwent ferroptosis. The susceptibility of human gingival fibroblasts to ferroptosis was investigated by in vitro cell cultures. We found that gingival fibroblasts undergo ferroptosis in periodontitis, and that periodontitis-induced tissue damage and bone loss were alleviated by inhibition of ferroptosis. Periodontitis-induced pro-inflammatory immune responses was featured by profound elevation of fibroblast-derived Interleukin-6, which was attenuated by ferroptosis inhibition. These results indicated fibroblast ferroptosis as a new clue to unveiling the cellular and molecular basis for periodontitis-induced tissue damage. Involvement of ferroptosis/Interleukin-6 signaling in the pathogenic process suggested a potential target for immunopharmacological approaches to curing periodontitis.

Changes of Oral Flora, Inflammatory Factors, and Immune Function Indicators in Patients with Chronic Periodontitis and Their Clinical Significance

This research focuses on investigating the changes of oral flora, inflammatory factors, and immune function indicators in patients with chronic periodontitis (CP) and their clinical significances. Clinical indices such as gingival index (GI) and sulcus bleeding index (SBI) of the study subjects were recorded. The levels of oral flora, inflammatory factors and T lymphocyte subsets in gingival crevicular fluid (GCF) of the study subjects were measured. To analyze the correlation between GI and gingival SBI and oral flora, inflammatory factors, and immune function indicators, Pearson correlation analysis was performed. Porphyromonas gingivalis, Streptococcus digestiveis, Prevotella intermedia, Veronococcus, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-8, CD3+, CD4+, and CD4+/CD8+ had a positive correlation with GI and SBI, while IL-10 and CD8+ were negatively correlated with GI and SBI. Oral flora, inflammatory factors and immune function indicators levels are largely elevated in patients with CP and they are correlated with CP clinical indicators.

Digital photometric analysis of gingival response to periodontal treatment

OBJECTIVES

The color is a major factor in determining inflammation status in most gingival indices. Current indices have limitations mainly due to subjective nature. Digital color analysis can provide objective and accurate measurements. Thus, the present study aimed to assess by digital tool the gingival color in the different stages of an active periodontal treatment.

METHODS

Forty patients (19 males and 21 females) diagnosed with periodontitis (stage III/ IV, grade C) and treated surgically were included in the study. Clinical data (probing depth, bleeding on probing, clinical attachment level, gingival index, and gingival recession) and photographs by digital single-lens-reflex (DSLR) camera were recorded before initial periodontal treatment, which included scaling and root surface debridement (T0); the same parameters were then re-evaluated 6-8 weeks (T1) and 3 months after periodontal surgery (regenerative/resective) (T2). Differences between clinical parameters were calculated. The color space defined by the International Commission on Illumination (CIELab) was used to analyze gingival color.

RESULTS

In 56 periodontal surgical sites, 168 photographs were taken. The a*-value of the CIELab color system (higher a*- value translate to a stronger red color) was significantly reduced between T0 to T1 and further decreased at T2 (32.01, 29.28, and 27.45 respectively). Significant improvement in clinical parameters were found between T0 to T1 and T1 to T2. Sub-analysis of two distinct surgical interventions revealed that only regenerative procedure improved the a*-value, which was significantly correlated with pocket depth reduction.

CONCLUSIONS

Photometric analysis can be used to assess gingival color change during periodontal treatment of patients with periodontitis.

CLINICAL SIGNIFICANCE

Gingival inflammation is a major factor in periodontal assessment; nevertheless, all current gingival inflammation indices are partially subjective and only semi-quantitative. The digital photometric analysis may allow for accurate and objective gingival color assessment during periodontal treatment.

Potentilloside A, a New Flavonol-bis-Glucuronide from the Leaves of Potentilla chinensis, Inhibits TNF-α-Induced ROS Generation and MMP-1 Secretion

The major contributor to skin aging is UV radiation, which activates pro-inflammatory cytokines including TNF-α. TNF-α is involved in the acceleration of skin aging via ROS generation and MMP-1 secretion. In our preliminary study, a 30% EtOH extract from the leaves of Potentilla chinensis (LPCE) significantly inhibited TNF-α-induced ROS generation in human dermal fibroblasts (HDFs). Therefore, the objective of this study is to identify the active components in LPCE. A new flavonol-bis-glucuronide (potentilloside A, 1) and 14 known compounds (2-15) were isolated from an LPCE by repeated chromatography. The chemical structure of the new compound 1 was determined by analyzing its spectroscopic data (NMR and HRMS) and by acidic hydrolysis. Nine flavonols (2-9 and 11) and two flavone glycosides (12 and 13) from P. chinensis were reported for the first time in this study. Next, we evaluated the effects of the isolates (1-15) on TNF-α-induced ROS generation in HDFs. As a result, all compounds significantly inhibited ROS generation. Furthermore, LPCE and potentilloside A (1) remarkably suppressed MMP-1 secretion in HDFs stimulated by TNF-α. The data suggested that LPCE and potentilloside A (1) are worthy of further experiments for their potential as anti-skin aging agents.

Continuous Oral Administration of Sonicated P. gingivalis Delays Rat Skeletal Muscle Healing Post-Treadmill Training

BACKGROUND

A delay in muscle repair interferes with the effect of training or exercise; therefore, it is important to identify the factors that delay muscle repair. P. gingivalis, one of the most common periodontal disease pathogens, has the potential to inhibit muscle repair after training, as inferred from a previous study. To assess the expression of satellite cells in this in vivo study, we evaluated the relationship between P. gingivalis and muscle regeneration after training.

METHODS

A total of 20 male Wistar rats (eight weeks in age) were randomly divided into two groups: one orally administered sonicated P. gingivalis four times per week for six weeks (PG group) and one given no treatment (NT group). After four weeks of training using a treadmill, the gastrocnemius was evaluated using histology of the cross-sectional area (CSA) of myotubes and immunohistochemistry of the expression of skeletal muscle satellite cells. In addition, an endurance test was performed a day before euthanization.

RESULTS

The CSA and expression of Pax7+/MyoD- and Pax7+/MyoD+ cells were not significantly different between the groups. However, the expression of Pax7-/MyoD+ cells and running time until exhaustion were significantly lower in the PG group.

CONCLUSIONS

Infection with P. gingivalis likely interferes with muscle repair after training.

HSP90AA1 promotes the inflammation in human gingival fibroblasts induced by Porphyromonas gingivalis lipopolysaccharide via regulating of autophagy

BACKGROUND

Peri-implantitis of tooth seriously affects the life quality of patients. This study aimed to investigate the role of HSP90AA1 in the inflammatory of human gingival fibroblasts (HGFs) induced by porphyromonas gingivalis lipopolysaccharide (Pg-LPS), and to provide a potential therapeutic target for clinical treatment of peri-implantitis.

METHODS

Pg-LPS (0.1, 1, 10 μg/mL) was used to construct the inflammatory model of HGFs to evaluate the effect of Pg-LPS on HGFs. Then HSP90AA1-siRNA was transfected to construct HSP90AA1 low expression HGFs cell line, and 3-MA was also added. After that, cell viability, apoptosis, the contents of inflammatory cytokines were detected by CCK-8, flow cytometry and ELISA assay, respectively. Intracellular ROS, the expressions of HSP90α, HSP90β were detected by immunofluorescence. The levels of HSP90AA1, p-NF-κB p65/NF-κB p65, LC3 II/I, ATG5, Beclin-1 and TLR protein were detected by western blot.

RESULTS

Pg-LPS treatment didn't affect the viability of HGFs cells, but induced the cell apoptosis and ROS generation, increased the contents of IL-1β, IL-6, TNF-α, and the protein expressions of HSP90AA1, p-NF-κBp65/NF-κBp65, LC3II/I, ATG5, and Beclin-1 in HGFs. While HSP90AA1-siRNA transfected into Pg-LPS induced HGFs significantly reduced the HSP90AA1, HSP90α, HSP90β expression, decreased the inflammatory factors, ROS generation, cell apoptosis rate, and autophagy-related proteins and TLR2/4 protein levels. What's more, the addition of autophagy inhibitor 3-MA further promote the effect of HSP90AA1-siRNA on Pg-LPS treated HGFs.

CONCLUSIONS

This study showed that HSP90AA1 promoted the inflammatory response of Pg-LPS induced HGFs by regulating autophagy. The addition of 3-MA further confirmed that autophagy may mediate siHSP90AA1 to enhance the inflammatory response.

Metabolomics profiling reveals berberine-inhibited inflammatory response in human gingival fibroblasts by regulating the LPS-induced apoptosis signaling pathway

This article examines berberine’s biological effects and molecular mechanisms with an inflammatory response model induced by lipopolysaccharide (LPS) in human gingival fibroblasts (HGFs) using metabolomics. The viability of HGFs was determined using the cell counting kit-8 (CCK8). ELISA was used to measure inflammatory cytokines, including interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor- α (TNF-α). An investigation of western blots was conducted to investigate the related proteins of apoptosis. Low concentrations of berberine (0.1, 0.5, and 1 μmol L⁻¹) did not affect HGF growth, whereas high concentrations of berberine (5–25 μmol L⁻¹) significantly activated cell proliferation. Berberine suppressed the elevated secretion of IL-6, IL-1β, and TNF-α induced by LPS in HGF. Western blot analysis showed that 10 μmol L⁻¹ of berberine significantly inhibited LPS-induced apoptosis signaling pathway activation. Our results suggested that berberine could inhibit LPS-induced apoptosis and the production of proinflammatory mediators in HGFs cells. Berberine may be a potential therapeutic drug for the management of periodontitis.

Initial biocompatibility of novel resins for 3D printed fixed dental prostheses

OBJECTIVES

Several materials for 3D printing of fixed dental prostheses (FDP) have been recently introduced. This study aims to evaluate the initial biocompatibility of novel printable resins for manufacturing temporary and permanent FDP.

METHODS

Specimens of five printable resins (VarseoSmile Crown plus, NextDent C&B MFH, VarseoSmile Temp, Temp PRINT, P Pro Crown & Bridge), two types of resins for subtractive manufacturing (Tetric CAD, Telio CAD) and two types of resins with conventional curing processes (Tetric EvoCeram, Protemp 4) were produced and finished. Post-processing was strictly performed according to the manufacturer's protocol. Biocompatibility was evaluated by eluting specimens with cell culture medium and treating human gingival fibroblast cells with the eluates. A 72-hour continuous read cell viability assay measuring the reducing potential of the cells was performed. The cellular inflammatory response in terms of IL-6 and PGE₂ levels was determined with specific ELISAs. Oxidative stress was determined by measuring oxidized glutathione concentrations after exposure to the resin eluates. A luminescence-based apoptosis assay was used to detect apoptosis.

RESULTS

Tetric CAD and Telio CAD were slightly toxic. All other resins were moderately to severely cytotoxic. VarseoSmile Crown plus and P Pro Crown & Bridge significantly enhanced PGE₂ levels. Higher concentrations of oxidized gluthatione were determined in the presence of Telio CAD, VarseoSmile Temp and P Pro Crown & Bridge. Tetric EvoCeram and Protemp 4 reduced intracellular gluthatione levels. All printable resins slightly induced apoptosis.

SIGNIFICANCE

Further post-processing steps such as additional curing and washing may improve the biocompatibility of printable materials.