Cystatin C: immunoregulation role in macrophages infected with Porphyromonas gingivalis.

Background: Periodontitis is a chronic infectious disease, characterized by an exacerbated inflammatory response and a progressive loss of the supporting tissues of the teeth. Porphyromonas gingivalis is a key etiologic agent in periodontitis. Cystatin C is an antimicrobial salivary peptide that inhibits the growth of P. gingivalis. This study aimed to evaluate the antimicrobial activity of this peptide and its effect on cytokine production, nitric oxide (NO) release, reactive oxygen species (ROS) production, and programmed cell death in human macrophages infected with P. gingivalis. Methods: Monocyte-derived macrophages generated from peripheral blood were infected with P. gingivalis (MOI 1:10) and stimulated with cystatin C (2.75 µg/ml) for 24 h. The intracellular localization of P. gingivalis and cystatin C was determined by immunofluorescence and transmission electron microscopy (TEM). The intracellular antimicrobial activity of cystatin C in macrophages was assessed by counting Colony Forming Units (CFU). ELISA assay was performed to assess inflammatory (TNFα, IL-1ß) and anti-inflammatory (IL-10) cytokines. The production of nitrites and ROS was analyzed by Griess reaction and incubation with 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), respectively. Programmed cell death was assessed with the TUNEL assay, Annexin-V, and caspase activity was also determined. Results: Our results showed that cystatin C inhibits the extracellular growth of P. gingivalis. In addition, this peptide is internalized in the infected macrophage, decreases the intracellular bacterial load, and reduces the production of inflammatory cytokines and NO. Interestingly, peptide treatment increased ROS production and substantially decreased bacterial-induced macrophage apoptosis. Conclusions: Cystatin C has antimicrobial and immuno-regulatory activity in macrophages infected with P. gingivalis. These findings highlight the importance of understanding the properties of cystatin C for its possible therapeutic use against oral infections such as periodontitis.

The impact of systemic administration of polyphenols on periodontitis associated with diabetes mellitus: a systematic review.

OBJECTIVE: The aim of this work was to explore the potential of polyphenol supplement consumption in enhancing the treatment of periodontitis and diabetes mellitus in both diabetic animals and humans. MATERIALS AND METHODS: A comprehensive search across eight databases (MEDLINE, EBSCO, Taylor & Francis, PRIMO, Web of Science, Wiley Online Library, ScienceDirect, and SAGE Journals) and two registers (ClinicalTrials.gov and Cochrane Library Trials) was conducted. Methodological quality assessment employed the Cochrane Collaboration Risk of Bias Assessment Tool for randomised controlled trials and the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias Tool for experimental animal studies. RESULTS: Ten articles meeting inclusion criteria were identified. Three clinical studies demonstrated significant reductions in probing depth (PD) and clinical attachment loss (CAL). Ginger supplementation showed a decrease in CAL (-0.57 ± 0.50 vs. -0.14 ± 0.35, p = 0.003) and PD (-0.52 ± 0.51 vs. -0.19 ± 0.51, p = 0.04), while resveratrol supplementation exhibited a reduction in PD (-1.1 ± 0.58 vs. -0.6 ± 0.47, p < 0.001). Additionally, cranberry juice supplementation led to a decrease in PD (-0.56 ± 0.03, p < 0.001). However, there was no significant improvement in inflammation status. Although polyphenol supplementation did not impact fasting blood glucose levels, it did result in improved insulin resistance (3.66 ± 0.97 vs. 4.49 ± 1.56, p = 0.045). In diabetic animals, six studies reported a significant reduction (p < 0.05) in bone loss along with marked improvements in inflammation status. CONCLUSIONS: Despite the promising results observed in the included studies, the overall evidence supporting the positive effects of polyphenols on periodontal and diabetes mellitus status, along with their anti-inflammatory properties, remains inadequate.

Mechanism of action of Coptidis Rhizome in treating periodontitis based on network pharmacology and in vitro validation.

OBJECTIVE: Explore the therapeutic mechanism of Coptidis Rhizome (CR) in periodontitis using network pharmacology, and validate it through molecular docking and in vitro experiments. METHODS: Screened potential active components and target genes of CR from TCMSP and Swiss databases. Identified periodontitis-related target genes using GeneCards. Found common target genes using Venny. Conducted GO and KEGG pathway analysis. Performed molecular docking and in vitro experiments using Berberine, the main active component of CR, on lymphocytes from healthy and periodontitis patients. Assessed effects on inflammatory factors using CCK-8, flow cytometry, and ELISA. RESULTS: Fourteen active components and 291 targets of CR were identified. 30 intersecting target genes with periodontitis were found. GO and KEGG analysis revealed oxidative stress response and IL-17 signaling pathway as key mechanisms. Molecular docking showed strong binding of Berberine with ALOX5, AKT1, NOS2, and TNF. In vitro experiments have demonstrated the ability of berberine to inhibit the expression of Th17 + and other immune related cells in LPS stimulated lymphocytes, and reduce the secretion of IL-6, IL-8, and IL-17. CONCLUSION: CR treats periodontitis through a multi-component, multi-target, and multi-pathway approach. Berberine, its key component, acts through the IL-17 signaling pathway to exert anti-inflammatory effects.

Oroxylin A inhibits inflammatory cytokines in periodontitis via HO­1.

Periodontal disease is a common infectious disease that can lead to the loss of teeth. Hower how to effectively suppress the inflammation with medication is unclear. The aim of the present study was to investigate the anti­inflammatory effect of Oroxylin A in periodontitis and its potential role through heme oxygenase­1 (HO­1). Primary rat gingival fibroblasts (RGFs) were cultured using the tissue block method and identified by immunofluorescence. Following lipopolysaccharide (LPS) stimulation of RGFs, Oroxylin A was administered at 50, 100, 200 or 400 µg/ml. Reverse transcription­quantitative PCR was used to assess mRNA expression of cyclooxygenase (COX)­2, TNF­α, RANKL and osteoprotegerin (OPG). Western blotting was used to detect protein expression levels of COX ­2, TNF­α, RANKL and OPG. Following HO­1 knockdown, the same treatment was performed. The expression of COX­2 in rat gingival tissue was observed by immunohistochemistry. One­way analysis of variance and Student's t test were used for statistical analysis. Oroxylin A downregulated mRNA expression of COX­2, TNF­α, RANKL and OPG in LPS­induced RGFs. With increase of Oroxylin A dose, the expression of HO­1 was gradually upregulated. When HO­1 was knocked down, Oroxylin A did not downregulate the expression of COX­2, TNF­α, RANKL and OPG in LPS­induced RGFs. Immunohistochemical results showed that expression of COX­2 was downregulated by Oroxylin A, and the expression of TNF­α, RANKL and OPG were also downregulated. Oroxylin A decreased expression of inflammatory cytokines in LPS­induced RGFs and had a good inhibitory effect on periodontitis in rats.

Quorum-quenching enzyme Est816 assisted antibiotics against periodontitis induced by Aggregatibacter actinomycetemcomitans in rats.

Introduction: Quorum-quenching enzyme Est816 hydrolyzes the lactone rings of N-acyl homoserine lactones, effectively blocking the biofilm formation and development of Gram-negative bacteria. However, its applications in the oral field is limited. This study aimed to evaluate the efficacy of enzyme Est816 in combination with antibiotics against periodontitis induced by Aggregatibacter actinomycetemcomitans in vitro and in vivo. Methods: The antimicrobial efficacy of enzyme Est816 in combination with minocycline, metronidazole, and amoxicillin was determined using the minimum inhibitory concentration test. The anti-biofilm effect of enzyme Est816 was assessed using scanning electron microscopy, live/dead bacterial staining, crystal violet staining, and real-time quantitative PCR. Biocompatibility of enzyme Est816 was assessed in human gingival fibroblasts (HGF) by staining. A rat model of periodontitis was established to evaluate the effect of enzyme Est816 combined with minocycline using micro-computed tomography and histological staining. Results: Compared to minocycline, metronidazole, and amoxicillin treatment alone, simultaneous treatment with enzyme Est816 increased the sensitivity of biofilm bacteria to antibiotics. Enzyme Est816 with minocycline exhibited the highest rate of biofilm clearance and high biocompatibility. Moreover, the combination of enzyme Est816 with antibiotics improved the antibiofilm effects of the antibiotics synergistically, reducing the expression of the virulence factor leukotoxin gene (ltxA) and fimbria-associated gene (rcpA). Likewise, the combination of enzyme Est816 with minocycline exhibited a remarkable inhibitory effect on bone resorption and inflammation damage in a rat model of periodontitis. Discussion: The combination of enzyme Est816 with antibiotics represents a prospective anti-biofilm strategy with the potential to treat periodontitis.

Sinensetin protects against periodontitis through binding to Bach1 enhancing its ubiquitination degradation and improving oxidative stress.

Periodontitis is a chronic inflammatory and immune reactive disease induced by the subgingival biofilm. The therapeutic effect for susceptible patients is often unsatisfactory due to excessive inflammatory response and oxidative stress. Sinensetin (Sin) is a nature polymethoxylated flavonoid with anti-inflammatory and antioxidant activities. Our study aimed to explore the beneficial effect of Sin on periodontitis and the specific molecular mechanisms. We found that Sin attenuated oxidative stress and inflammatory levels of periodontal ligament cells (PDLCs) under inflammatory conditions. Administered Sin to rats with ligation-induced periodontitis models exhibited a protective effect against periodontitis in vivo. By molecular docking, we identified Bach1 as a strong binding target of Sin, and this binding was further verified by cellular thermal displacement assay and immunofluorescence assays. Chromatin immunoprecipitation-quantitative polymerase chain reaction results also revealed that Sin obstructed the binding of Bach1 to the HMOX1 promoter, subsequently upregulating the expression of the key antioxidant factor HO-1. Further functional experiments with Bach1 knocked down and overexpressed verified Bach1 as a key target for Sin to exert its antioxidant effects. Additionally, we demonstrated that Sin prompted the reduction of Bach1 by potentiating the ubiquitination degradation of Bach1, thereby inducing HO-1 expression and inhibiting oxidative stress. Overall, Sin could be a promising drug candidate for the treatment of periodontitis by targeting binding to Bach1.

Erythrocyte-Like Mesoporous PDA@CeO2 Nanozyme with Dual Drugs for Periodontitis Treatment.

Periodontitis is a chronic oral inflammatory disease with the characteristic of excess oxidative stress in the inflammatory site, dramatically decreasing the quality of life. Studies show that nanozymes can be ideal candidates for ROS scavenging in periodontitis. Here, we design a multipath anti-inflammatory mesoporous polydopamine@cerium oxide nanobowl (mPDA@CeO2 NB) with multienzyme mimicking properties, which combines the advantages of both CeO2 NP and mPDA NB for synergistically eliminating reactive oxygen species (ROS), including hydroxyl radical (•OH), hydrogen peroxide (H2O2), and superoxide (O2•-). Besides, the erythrocyte-like structure of mNBs makes them a facility for cell uptake, and the mesopores can load both hydrophobic and hydrophilic drugs for combined anti-inflammatory therapy. In vitro and in vivo experiments prove that the combination of CeO2 and mPDA can synergistically achieve multiple complementary ROS eliminations and suppression of ROS-induced inflammation. Moreover, the ROS regulation plus anti-inflammatory drugs in one mPDA@CeO2 NB prevents the progression of periodontitis in a mouse model. Therefore, the design of mPDA@CeO2 NB with these excellent properties provides a therapeutic strategy for inflammatory diseases.

Isobavachin attenuates osteoclastogenesis and periodontitis-induced bone loss by inhibiting cellular iron accumulation and mitochondrial biogenesis.

As bone-resorbing cells rich in mitochondria, osteoclasts require high iron uptake to promote mitochondrial biogenesis and maintain a high-energy metabolic state for active bone resorption. Given that abnormal osteoclast formation and activation leads to imbalanced bone remodeling and osteolytic bone loss, osteoclasts may be crucial targets for treating osteolytic diseases such as periodontitis. Isobavachin (IBA), a natural flavonoid compound, has been confirmed to be an inhibitor of receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation from bone marrow-derived macrophages (BMMs). However, its effects on periodontitis-induced bone loss and the potential mechanism of its anti-osteoclastogenesis effect remain unclear. Our study demonstrated that IBA suppressed RANKL-induced osteoclastogenesis in BMMs and RAW264.7 cells and inhibited osteoclast-mediated bone resorption in vitro. Transcriptomic analysis indicated that iron homeostasis and reactive oxygen species (ROS) metabolic process were enriched among the differentially expressed genes following IBA treatment. IBA exerted its anti-osteoclastogenesis effect by inhibiting iron accumulation in osteoclasts. Mechanistically, IBA attenuated iron accumulation in RANKL-induced osteoclasts by inhibiting the mitogen-activated protein kinase (MAPK) pathway to upregulate ferroportin1 (Fpn1) expression and promote Fpn1-mediated intracellular iron efflux. We also found that IBA inhibited mitochondrial biogenesis and function, and reduced RANKL-induced ROS generation in osteoclasts. Furthermore, IBA attenuated periodontitis-induced bone loss by reducing osteoclastogenesis in vivo. Overall, these results suggest that IBA may serve as a promising therapeutic strategy for bone diseases characterized by osteoclastic bone resorption.

Streptococcus intermedius causing primary bacterial ventriculitis in a patient with severe periodontitis - a case report.

BACKGROUND: Streptococcus intermedius is a member of the S. anginosus group and is part of the normal oral microbiota. It can cause pyogenic infections in various organs, primarily in the head and neck area, including brain abscesses and meningitis. However, ventriculitis due to periodontitis has not been reported previously. CASE PRESENTATION: A 64-year-old male was admitted to the hospital with a headache, fever and later imbalance, blurred vision, and general slowness. Neurological examination revealed nuchal rigidity and general clumsiness. Meningitis was suspected, and the patient was treated with dexamethasone, ceftriaxone and acyclovir. A brain computer tomography (CT) scan was normal, and cerebrospinal fluid (CSF) Gram staining and bacterial cultures remained negative, so the antibacterial treatment was discontinued. Nine days after admission, the patient's condition deteriorated. The antibacterial treatment was restarted, and a brain magnetic resonance imaging revealed ventriculitis. A subsequent CT scan showed hydrocephalus, so a ventriculostomy was performed. In CSF Gram staining, chains of gram-positive cocci were observed. Bacterial cultures remained negative, but a bacterial PCR detected Streptococcus intermedius. An orthopantomography revealed advanced periodontal destruction in several teeth and periapical abscesses, which were subsequently operated on. The patient was discharged in good condition after one month. CONCLUSIONS: Poor dental health can lead to life-threatening infections in the central nervous system, even in a completely healthy individual. Primary bacterial ventriculitis is a diagnostic challenge, which may result in delayed treatment and increased mortality.

The impact of Thiopeptide antibiotics on inflammatory responses in periodontal tissues through the regulation of the MAPK pathway.

Periodontitis is a bacteria-induced inflammatory disease that damages the tissues supporting the teeth, gums, periodontal ligaments, and alveolar bone. Conventional treatments such as surgical procedures, anti-inflammatory drugs, and antibiotics, are somewhat effective; however, these may lead to discomfort and adverse events, thereby affecting patient outcomes. Therefore, this study aimed to find an effective method to prevent the onset of periodontal disease and explore the specific mechanisms of their action.The impact of thiostrepton on Porphyromonas gingivalis and periodontal ligament stem cells was evaluated in an inflammatory microenvironment. In vivo experiments were performed using a mouse periodontitis model to assess the effectiveness of locally applied thiostrepton combined with a silk fibroin hydrogel in impeding periodontitis progression. Thiostrepton exhibited significant antimicrobial effects against Porphyromonas gingivalis and anti-inflammatory properties by regulating the MAPK pathway through DUSP2. Locally applied thiostrepton effectively impeded the progression of periodontitis and reduced tissue damage. Thiostrepton treatment is a promising and tolerable preventive strategy for periodontitis, offering antimicrobial and anti-inflammatory benefits. These findings suggest the potential of thiostrepton as a valuable addition to periodontitis management, warranting further research and clinical exploration to improve patient outcomes.

Salicin alleviates periodontitis via Tas2r143/gustducin signaling in fibroblasts.

Introduction: Cells expressing taste signaling elements in non-gustatory tissues have been described as solitary chemosensory cells (SCCs) or tuft cells. These "taste-like" cells play a critical role in the maintenance of tissue homeostasis. Although the expression of SCC markers and taste signaling constituents has been identified in mouse gingivae, their role in periodontal homeostasis is still unclear. Methods: Public RNA sequencing datasets were re-analyzed and further validated with RT-PCR/qRT-PCR and immunofluorescent staining to explore the expression of TAS2Rs and downstream signaling constituents in mouse gingival fibroblasts (MGFs). The specific action of salicin on MGFs via Tas2r143 was validated with RNA silence, heterologous expression of taste receptor/Gα-gustducin and calcium imaging. The anti-inflammatory effects of salicin against LPS-induced MGFs were investigated in cell cultures, and were further validated with a ligature-induced periodontitis mouse model using Ga-gustducin-null (Gnat3-/-) mice. Results: The expression of Tas2r143, Gnat3, Plcb2, and TrpM5 was detected in MGFs. Moreover, salicin could activate Tas2r143, elicited taste signaling and thus inhibited LPS-induced chemokines expression (CXCL1, CXCL2, and CXCL5) in MGFs. Consistently, salicin-treatment inhibited periodontal bone loss, inflammatory/chemotactic factors expression, and neutrophil infiltration in periodontitis mice, while these effects were abolished in Gnat3-/- mice. Discussion: Gingival fibroblasts play a critical role in the maintenance of periodontal homeostasis via "SCC-like" activity. Salicin can activate Tas2r143-mediated bitter taste signaling and thus alleviate periodontitis in mouse, indicating a promising approach to the resolution of periodontal inflammation via stimulating the "SCC-like" function of gingival fibroblasts.

The potential use of nanozymes as an antibacterial agents in oral infection, periodontitis, and peri-implantitis.

Several studies suggest that oral pathogenic biofilms cause persistent oral infections. Among these is periodontitis, a prevalent condition brought on by plaque biofilm. It can even result in tooth loss. Furthermore, the accumulation of germs around a dental implant may lead to peri-implantitis, which damages the surrounding bone and gum tissue. Furthermore, bacterial biofilm contamination on the implant causes soft tissue irritation and adjacent bone resorption, severely compromising dental health. On decontaminated implant surfaces, however, re-osseointegration cannot be induced by standard biofilm removal techniques such as mechanical cleaning and antiseptic treatment. A family of nanoparticles known as nanozymes (NZs) comprise highly catalytically active multivalent metal components. The most often employed NZs with antibacterial activity are those that have peroxidase (POD) activity, among other types of NZs. Since NZs are less expensive, more easily produced, and more stable than natural enzymes, they hold great promise for use in various applications, including treating microbial infections. NZs have significantly contributed to studying implant success rates and periodontal health maintenance in periodontics and implantology. An extensive analysis of the research on various NZs and their applications in managing oral health conditions, including dental caries, dental pulp disorders, oral ulcers, peri-implantitis, and bacterial infections of the mouth. To combat bacteria, this review concentrates on NZs that imitate the activity of enzymes in implantology and periodontology. With a view to the future, there are several ways that NZs might be used to treat dental disorders antibacterially.

Engineering Nitric Oxide-Releasing Antimicrobial Dental Coating for Targeted Gingival Therapy.

Bacterial biofilms play a central role in the development and progression of periodontitis, a chronic inflammatory condition that affects the oral cavity. One solution to current treatment constraints is using nitric oxide (NO)─with inherent antimicrobial properties. In this study, an antimicrobial coating is developed from the NO donor S-nitroso-N-acetylpenicillamine (SNAP) embedded within polyethylene glycol (PEG) to prevent periodontitis. The SNAP-PEG coating design enabled a controlled NO release, achieving tunable NO levels for more than 24 h. Testing the SNAP-PEG composite on dental floss showed its effectiveness as a uniform and bioactive coating. The coating exhibited antibacterial properties against Streptococcus mutans and Escherichia coli, with inhibition zones measuring up to 7.50 ± 0.28 and 14.80 ± 0.46 mm2, respectively. Furthermore, SNAP-PEG coating materials were found to be stable when stored at room temperature, with 93.65% of SNAP remaining after 28 d. The coatings were biocompatible against HGF and hFOB 1.19 cells through a 24 h controlled release study. This study presents a facile method to utilize controlled NO release with dental antimicrobial coatings comprising SNAP-PEG. This coating can be easily applied to various substrates, providing a user-friendly approach for targeted self-care in managing gingival infections associated with periodontitis.

Advances in Hydrogels for Periodontitis Treatment.

Periodontitis is a common condition characterized by a bacterial infection and the disruption of the body's immune-inflammatory response, which causes damage to the teeth and supporting tissues and eventually results in tooth loss. Current therapy involves the systemic and local administration of antibiotics. However, the existing treatments cannot exert effective, sustained release and maintain an effective therapeutic concentration of the drug at the lesion site. Hydrogels are used to treat periodontitis due to their low cytotoxicity, exceptional water retention capability, and controlled drug release profile. Hydrogels can imitate the extracellular matrix of periodontal cells while offering suitable sites to load antibiotics. This article reviews the utilization of hydrogels for periodontitis therapy based on the pathogenesis and clinical manifestations of the disease. Additionally, the latest therapeutic strategies for smart hydrogels and the main techniques for hydrogel preparation have been discussed. The information will aid in designing and preparing future hydrogels for periodontitis treatment.

Microbiological Effects of Sodium Hypochlorite/-Amino Acids and Cross-linked Hyaluronic Acid Adjunctive to Non-surgical Periodontal Treatment.

PURPOSE: To investigate the microbiological outcomes obtained with either subgingival debridement (SD) in conjunction with a gel containing sodium hypochlorite and amino acids followed by subsequent application of a cross-linked hyaluronic acid gel (xHyA) gel, or with SD alone. MATERIALS AND METHODS: Forty-eight patients diagnosed with stages II-III (grades A/B) generalised periodontitis were randomly treated with either SD (control) or SD plus adjunctive sodium hypochlorite/amino acids and xHyA gel (test). Subgingival plaque samples were collected from the deepest site per quadrant in each patient at baseline and after 3 and 6 months. Pooled sample analysis was performed using a multiplex polymerase chain reaction (PCR)-based method for the identification of detection frequencies and changes in numbers of the following bacteria: Aggregatibacter actinomycetemcomitans (A.a), Porphyromonas gingivalis (P.g), Tannerella forsythia (T.f), Treponema denticola (T.d), and Prevotella intermedia (P.i). RESULTS: In terms of detection frequency, in the test group, statistically significant reductions were found for P.g, T.f, T.d and P.i (p < 0.05) after 6 months. In the control group, the detection frequencies of all investigated bacterial species at 6 months were comparable to the baseline values (p > 0.05). The comparison of the test and control groups revealed statistically significant differences in detection frequency for P.g (p = 0.034), T.d (p < 0.01) and P.i (p = 0.02) after 6 months, favouring the test group. Regarding reduction in detection frequency scores, at 6 months, statistically significant differences in favour of the test group were observed for all investigated bacterial species: A.a (p = 0.028), P.g (p = 0.028), T.f (p = 0.004), T.d (p <0.001), and P.i (p = 0.003). CONCLUSIONS: The present microbiological results, which are related to short-term outcomes up to 6 months post-treatment, support the adjunctive subgingival application of sodium hypochlorite/amino acids and xHyA to subgingival debridement in the treatment of periodontitis.

Ropinirole suppresses LPS-induced periodontal inflammation by inhibiting the NAT10 in an ac4C-dependent manner.

BACKGROUND: Periodontitis is a chronic osteolytic inflammatory disease, where anti-inflammatory intervention is critical for restricting periodontal damage and regenerating alveolar bone. Ropinirole, a dopamine D2 receptor agonist, has previously shown therapeutic potential for periodontitis but the underlying mechanism is still unclear. METHODS: Human gingival fibroblasts (HGFs) treated with LPS were considered to mimic periodontitis in vitro. The dosage of Ropinirole was selected through the cell viability of HGFs evaluation. The protective effects of Ropinirole on HGFs were evaluated by detecting cell viability, cell apoptosis, and pro-inflammatory factor levels. The molecular docking between NAT10 and Ropinirole was performed. The interaction relationship between NAT10 and KLF6 was verified by ac4C Acetylated RNA Immunoprecipitation followed by qPCR (acRIP-qPCR) and dual-luciferase reporter assay. RESULTS: Ropinirole alleviates LPS-induced damage of HGFs by promoting cell viability, inhibiting cell apoptosis and the levels of IL-1ß, IL-18, and TNF-α. Overexpression of NAT10 weakens the effects of Ropinirole on protecting HGFs. Meanwhile, NAT10-mediated ac4C RNA acetylation promotes KLF6 mRNA stability. Upregulation of KLF6 reversed the effects of NAT10 inhibition on HGFs. CONCLUSIONS: Taken together, Ropinirole protected HGFs through inhibiting the NAT10 ac4C RNA acetylation to decrease the KLF6 mRNA stability from LPS injury. The discovery of this pharmacological and molecular mechanism of Ropinirole further strengthens its therapeutic potential for periodontitis.

IGF2 promotes alveolar bone regeneration in murine periodontitis via inhibiting cGAS/STING-mediated M1 macrophage polarization.

Periodontitis is a chronic inflammatory disease with the destruction of supporting periodontal tissue. This study evaluated the role of insulin-like growth factor 2 (IGF2) in periodontitis by inhibiting the polarization of M1 macrophages via the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway. IGF2 was enriched in the gingival tissue of murine periodontitis model identified by RNA sequencing. IGF2 application alleviated the expression of pro-inflammatory factors and promoted osteogenesis and the expression of related genes and proteins in a dose-dependent manner in periodontitis. The result of micro-CT verified this finding. Both in vivo and in vitro results revealed that IGF2 decreased the polarization of M1 macrophages and pro-inflammatory factors by immunofluorescence staining, flow cytometry, western blotting and RT-PCR. IGF2 application promoted the osteogenic ability of periodontal ligament fibroblasts (PDLFs) indirectly via its inhibition of M1 polarization evaluated by alkaline phosphatase and alizarin red staining. Then, the cGAS/STING pathway was upregulated in periodontitis and macrophages challenged by LPS, the inhibition of which led to downregulation of M1 polarization. Furthermore, IGF2 could downregulate cGAS, STING and the phosphorylation of P65. Collectively, our study indicates IGF2 can regulate the polarization of M1 macrophages via the cGAS/STING pathway and highlights the promising future of IGF2 as a therapeutic treatment for periodontitis.

The application of phenylboronic acid pinacol ester functionalized ROS-responsive multifunctional nanoparticles in the treatment of Periodontitis.

Periodontitis is an inflammatory disease induced by the complex interactions between the host immune system and the microbiota of dental plaque. Oxidative stress and the inflammatory microenvironment resulting from periodontitis are among the primary factors contributing to the progression of the disease. Additionally, the presence of dental plaque microbiota plays a significant role in affecting the condition. Consequently, treatment strategies for periodontitis should be multi-faceted. In this study, a reactive oxygen species (ROS)-responsive drug delivery system was developed by structurally modifying hyaluronic acid (HA) with phenylboronic acid pinacol ester (PBAP). Curcumin (CUR) was encapsulated in this drug delivery system to form curcumin-loaded nanoparticles (HA@CUR NPs). The release results indicate that CUR can be rapidly released in a ROS environment to reach the concentration required for treatment. In terms of uptake, HA can effectively enhance cellular uptake of NPs because it specifically recognizes CD44 expressed by normal cells. Moreover, HA@CUR NPs not only retained the antimicrobial efficacy of CUR, but also exhibited more pronounced anti-inflammatory and anti-oxidative stress functions both in vivo and in vitro. This provides a good potential drug delivery system for the treatment of periodontitis, and could offer valuable insights for dental therapeutics targeting periodontal diseases.

Quercetin-loaded mesoporous nano-delivery system remodels osteoimmune microenvironment to regenerate alveolar bone in periodontitis via the miR-21a-5p/PDCD4/NF-κB pathway.

BACKGROUND: Impaired osteo-/angiogenesis, excessive inflammation, and imbalance of the osteoimmune homeostasis are involved in the pathogenesis of the alveolar bone defect caused by periodontitis. Unfortunately, there is still a lack of ideal therapeutic strategies for periodontitis that can regenerate the alveolar bone while remodeling the osteoimmune microenvironment. Quercetin, as a monomeric flavonoid, has multiple pharmacological activities, such as pro-regenerative, anti-inflammatory, and immunomodulatory effects. Despite its vast spectrum of pharmacological activities, quercetin's clinical application is limited due to its poor water solubility and low bioavailability. RESULTS: In this study, we fabricated a quercetin-loaded mesoporous bioactive glass (Quercetin/MBG) nano-delivery system with the function of continuously releasing quercetin, which could better promote the bone regeneration and regulate the immune microenvironment in the alveolar bone defect with periodontitis compared to pure MBG treatment. In particular, this nano-delivery system effectively decreased injection frequency of quercetin while yielding favorable therapeutic results. In view of the above excellent therapeutic effects achieved by the sustained release of quercetin, we further investigated its therapeutic mechanisms. Our findings indicated that under the periodontitis microenvironment, the intervention of quercetin could restore the osteo-/angiogenic capacity of periodontal ligament stem cells (PDLSCs), induce immune regulation of macrophages and exert an osteoimmunomodulatory effect. Furthermore, we also found that the above osteoimmunomodulatory effects of quercetin via macrophages could be partially blocked by the overexpression of a key microRNA--miR-21a-5p, which worked through inhibiting the expression of PDCD4 and activating the NF-κB signaling pathway. CONCLUSION: In summary, our study shows that quercetin-loaded mesoporous nano-delivery system has the potential to be a therapeutic approach for reconstructing alveolar bone defects in periodontitis. Furthermore, it also offers a new perspective for treating alveolar bone defects in periodontitis by inhibiting the expression of miR-21a-5p in macrophages and thereby creating a favorable osteoimmune microenvironment.

Injectable Nanocomposite Hydrogels with Strong Antibacterial, Osteoinductive, and ROS-Scavenging Capabilities for Periodontitis Treatment.

Injectable antibacterial and osteoinductive hydrogels have received considerable attention for promoting bone regeneration owing to their versatile functionalities. However, a current hydrogel with antibacterial, osteoinductive, and antioxidant properties by a facile method for periodontitis treatment is still missing. To overcome this issue, we designed an injectable hydrogel system (GPM) composed of gelatin, Ti3C2Tx MXene nanosheets, and poly-l-lysine using a simple enzymatic cross-linking technique. Physicochemical characterization demonstrated that the GPM hydrogel matrix exhibited excellent stability, moderate tissue adhesion ability, and good mechanical behavior. The GPM hydrogels significantly inhibited the growth of Porphyromonas gingivalis, scavenged reactive oxygen species, attenuated inflammatory responses, and enhanced bone tissue regeneration. Intriguingly, the arrangement of the junctional epithelium, alveolar bone volume, and alveolar bone height in the GPM-treated periodontal disease group recovered to that of the healthy group. Therefore, our injectable hydrogel system with versatile functions may serve as an excellent tissue scaffold for the treatment of periodontitis.