Metabolic Reconfiguration Activates Stemness and Immunomodulation of PDLSCs

Surface-Charge Tuned Polymeric Nanoemulsions for Carvacrol Delivery in Interkingdom Biofilms

Biofilms, intricate microbial communities entrenched in extracellular polymeric substance (EPS) matrices, pose formidable challenges in infectious disease treatment, especially in the context of interkingdom biofilms prevalent in the oral environment. This study investigates the potential of carvacrol-loaded biodegradable nanoemulsions (NEs) with systematically varied surface charges─cationic guanidinium (GMT-NE) and anionic carboxylate (CMT-NE). Zeta potentials of +25 mV (GMT-NE) and -33 mV (CMT-NE) underscore successful nanoemulsion fabrication (∼250 nm). Fluorescent labeling and dynamic tracking across three dimensions expose GMT-NE's superior diffusion into oral biofilms, yielding a robust antimicrobial effect with 99.99% killing for both streptococcal and Candida species and marked reductions in bacterial cell viability compared to CMT-NE (∼4-log reduction). Oral mucosa tissue cultures affirm the biocompatibility of both NEs with no morphological or structural changes, showcasing their potential for combating intractable biofilm infections in oral environment. This study advances our understanding of NE surface charges and their interactions within interkingdom biofilms, providing insights crucial for addressing complex infections involving bacteria and fungi in the demanding oral context.

Proanthocyanidins Ameliorate LPS-Inhibited Osteogenesis of PDLSCs by Restoring Lysine Lactylation

Periodontitis is a bacteria-induced inflammatory disease characterized by the progressive destruction of periodontal supporting tissues. Periodontal ligament stem cells (PDLSCs) are capable of differentiating into osteoblasts, which is an important stem cell source for endogenous periodontal tissue regeneration. Lysine lactylation (Kla) is a novel post-translational modification of proteins that is recently thought to be associated with osteogenic differentiation. Here, we found that lactylation levels are reduced both in the periodontal tissue of rats with periodontitis and lipopolysaccharide (LPS)-stimulated human PDLSCs. Proanthocyanidins were able to promote the osteogenesis of inflamed PDLSCs by restoring lactylation levels. Mechanistically, proanthocyanidins increased lactate production and restored the lactylation levels of PDLSCs, which recovered osteogenesis of inflamed PDLSCs via the Wnt/β-catenin pathway. These results provide evidence on how epigenetic regulation by pharmacological agents influence the osteogenic phenotype of stem cells and the process of periodontal tissue repair. Our current study highlights the valuable potential of natural product proanthocyanidins in the regenerative engineering of periodontal tissues.

Nanozyme-Based Robotics Approach for Targeting Fungal Infection

Fungal pathogens have been designated by the World Health Organization as microbial threats of the highest priority for global health. It remains a major challenge to improve antifungal efficacy at the site of infection while avoiding off-target effects, fungal spreading, and drug tolerance. Here, a nanozyme-based microrobotic platform is developed that directs localized catalysis to the infection site with microscale precision to achieve targeted and rapid fungal killing. Using electromagnetic field frequency modulation and fine-scale spatiotemporal control, structured iron oxide nanozyme assemblies are formed that display tunable dynamic shape transformation and catalysis activation. The catalytic activity varies depending on the motion, velocity, and shape providing controllable reactive oxygen species (ROS) generation. Unexpectedly, nanozyme assemblies bind avidly to fungal (Candida albicans) surfaces to enable concentrated accumulation and targeted ROS-mediated killing in situ. By exploiting these tunable properties and selective binding to fungi, localized antifungal activity is achieved using in vivo-like cell spheroid and animal tissue infection models. Structured nanozyme assemblies are directed to Candida-infected sites using programmable algorithms to perform precisely guided spatial targeting and on-site catalysis resulting in fungal eradication within 10 min. This nanozyme-based microrobotics approach provides a uniquely effective and targeted therapeutic modality for pathogen elimination at the infection site.

Natural compounds and mesenchymal stem cells: implications for inflammatory-impaired tissue regeneration

Inflammation is a common and important pathological process occurring in any part of the body and relating to a variety of diseases. Effective tissue repair is critical for the survival of impaired organisms. Considering the side effects of the currently used anti-inflammatory medications, new therapeutic agents are urgently needed for the improvement of regenerative capacities of inflammatory-impaired tissues. Mesenchymal stromal stem/progenitor cells (MSCs) are characterized by the capabilities of self-renewal and multipotent differentiation and exhibit immunomodulatory capacity. Due to the ability to modulate inflammatory phenotypes and immune responses, MSCs have been considered as a potential alternative therapy for autoimmune and inflammatory diseases. Natural compounds (NCs) are complex small multiple-target molecules mostly derived from plants and microorganisms, exhibiting therapeutic effects in many disorders, such as osteoporosis, diabetes, cancer, and inflammatory/autoimmune diseases. Recently, increasing studies focused on the prominent effects of NCs on MSCs, including the regulation of cell survival and inflammatory response, as well as osteogenic/adipogenic differentiation capacities, which indicate the roles of NCs on MSC-based cytotherapy in several inflammatory diseases. Their therapeutic effects and fewer side effects in numerous physiological processes, compared to chemosynthetic drugs, made them to be a new therapeutic avenue combined with MSCs for impaired tissue regeneration. Here we summarize the current understanding of the influence of NCs on MSCs and related downstream signaling pathways, specifically in pathological inflammatory conditions. In addition, the emerging concepts through the combination of NCs and MSCs to expand the therapeutic perspectives are highlighted. A promising MSC source from oral/dental tissues is also discussed, with a remarkable potential for MSC-based therapy in future clinical applications.

Mesenchymal Stromal Cells Derived from Dental Tissues: Immunomodulatory Properties and Clinical Potential

Mesenchymal stem/stromal cells (MSCs) are multipotent cells located in different areas of the human body. The oral cavity is considered a potential source of MSCs because they have been identified in several dental tissues (D-MSCs). Clinical trials in which cells from these sources were used have shown that they are effective and safe as treatments for tissue regeneration. Importantly, immunoregulatory capacity has been observed in all of these populations; however, this function may vary among the different types of MSCs. Since this property is of clinical interest for cell therapy protocols, it is relevant to analyze the differences in immunoregulatory capacity, as well as the mechanisms used by each type of MSC. Interestingly, D-MSCs are the most suitable source for regenerating mineralized tissues in the oral region. Furthermore, the clinical potential of D-MSCs is supported due to their adequate capacity for proliferation, migration, and differentiation. There is also evidence for their potential application in protocols against autoimmune diseases and other inflammatory conditions due to their immunosuppressive capacity. Therefore, in this review, the immunoregulatory mechanisms identified at the preclinical level in combination with the different types of MSCs found in dental tissues are described, in addition to a description of the clinical trials in which MSCs from these sources have been applied.

Glycometabolic reprogramming in cementoblasts: A vital target for enhancing cell mineralization

Cementum, a constituent part of periodontal tissues, has important adaptive and reparative functions. It serves to attach the tooth to alveolar bone and acts as a barrier delimit epithelial growth and bacteria evasion. A dynamic and highly responsive cementum is essential for maintaining occlusal relationships and the integrity of the root surface. It is a thin layer of mineralized tissue mainly produced by cementoblasts. Cementoblasts are osteoblast-like cells essential for the restoration of periodontal tissues. In recent years, glucose metabolism has been found to be critical in bone remodeling and osteoblast differentiation. However, the glucose metabolism of cementoblasts remains incompletely understood. First, immunohistochemistry staining and in vivo tracing with 18 F-fluorodeoxyglucose (18 F-FDG) revealed significantly higher glucose metabolism in cementum formation. To test the bioenergetic pathways of cementoblast differentiation, we compared the bioenergetic profiles of mineralized and unmineralized cementoblasts. As a result, we observed a significant increase in the consumption of glucose and production of lactate, coupled with the higher expression of glycolysis-related genes. However, the expression of oxidative phosphorylation-related genes was downregulated. The verified results were consistent with the RNA sequencing results. Likewise, targeted energy metabolomics shows that the levels of glycolytic metabolites were significantly higher in the mineralized cementoblasts. Seahorse assays identified an increase in glycolytic flux and reduced oxygen consumption during cementoblast mineralization. Apart from that, we also found that lactate dehydrogenase A (LDHA), a key glycolysis enzyme, positively regulates the mineralization of cementoblasts. In summary, cementoblasts mainly utilized glycolysis rather than oxidative phosphorylation during the mineralization process.

Clinical usage of dental stem cells and their derived extracellular vesicles

Stem cell-based therapies remain at the forefront of tissue engineering and regenerative medicine because stem cells are a unique cell source with enormous potential to treat incurable diseases and even extend lifespans. The search for the best stem cell candidates continues to evolve and in recent years, dental stem cells have received significant attention due to their easy accessibility, high plasticity, and multipotential properties. Dental stem cells have been the subject of extensive research in both animal models and human clinical trials over the past two decades, and have demonstrated significant potential in ocular therapy, bone tissue engineering, and, of course, therapeutic applications in dentistry such as regenerative endodontics and periodontal tissue regeneration. These new sources of cells may be advantageous for cellular therapy and the advancement of regenerative medicine strategies, such as allogeneic transplantation or therapy with extracellular vesicles (EVs), which are functional nanoscale membrane vesicles produced by cells. This chapter discusses the accumulating research findings on cell-based regenerative therapy utilizing dental stem cells and their derived EVs, which could be a viable tool for the treatment of a variety of diseases and hence extremely valuable to mankind in the long run.

Effects of non-steroidal anti-inflammatory drug (ibuprofen) in low and high dose on stemness and biological characteristics of human dental pulp-derived mesenchymal stem cells

PURPOSE

The effect of ibuprofen, an NSAID, on biological characteristics such as proliferation, viability, DNA damage and cell cycle in dental pulp derived stem cells (DPSCs) can be important for regenerative medicine. Our aim is to investigate how low and high doses of ibuprofen affect stem cell characteristics in DPSCs.

MATERIALS AND METHODS

DPSCs were isolated from human teeth and characterized by flow cytometry and differentiation tests. Low dose (0.1 mmol/L) and high dose (3 mmol/L) ibuprofen were administered to DPSCs. Surface markers between groups were analyzed by immunofluorescence staining. Membrane depolarization, DNA damage, viability and cell cycle analysis were performed between groups using biological activity test kits. Cellular proliferation was measured by the MTT and cell count kit. Statistical analyzes were performed using GraphPad Prism software.

RESULTS

High dose ibuprofen significantly increased CD44 and CD73 expression in DPSCs. High-dose ibuprofen significantly reduced mitochondrial membrane depolarization in DPSCs. It was determined that DNA damage in DPSCs decreased significantly with high dose ibuprofen. Parallel to this, cell viability increased significantly in the ibuprofen applied groups. High-dose ibuprofen was found to increase mitotic activity in DPSCs. Proliferation in DPSCs increased in parallel with the increase in mitosis stage because of high-dose ibuprofen administration compared to the control and low-dose ibuprofen groups. Our proliferation findings appeared to support cell cycle analyses.

CONCLUSION

High dose ibuprofen improved the immunophenotypes and biological activities of DPSCs. The combination of ibuprofen in the use of DPSCs in regenerative medicine can make stem cell therapy more effective.

What Has Immunology Brought to Periodontal Disease in Recent Years?

Recent decades have shed a new light on the pathomechanism of periodontal inflammation. While classic periodontology concentrates on biofilm control, oral hygiene improvement, professional tooth cleaning and surgical correction of damaged periodontal tissues, new aspects of the destruction mechanisms are being raised. Among them, the greatest attention is paid to the influence of host response on the clinical manifestations of the disease. Numerous studies have proved that the shift from gingivitis to periodontitis is not a simple progress of the disease, but an event occurring only in susceptible individuals. Susceptibility may result from appearance of local factors facilitating biofilm accumulation and/or maturation, or from systemic features, among which over-reaction and prolonged agitation of non-specific component of inflammatory response is crucial. The present paper summarizes the association between periodontology and immunology and updates the knowledge accrued mostly in the recent years. After a brief explanation of advances in understanding of the disease aetiology, the most studied and potentially viable immunological markers of periodontal disease are presented. Possible new therapeutic strategies, exploiting knowledge about the nature of host response—immunomodulation and reduction of chronic oxidative stress—are also presented.

Advances in novel therapeutic approaches for periodontal diseases

Periodontal diseases are pathological processes resulting from infections and inflammation affecting the periodontium or the tissue surrounding and supporting the teeth. Pathogenic bacteria living in complex biofilms initiate and perpetuate this disease in susceptible hosts. In some cases, broad-spectrum antibiotic therapy has been a treatment of choice to control bacterial infection. However, increasing antibiotic resistance among periodontal pathogens has become a significant challenge when treating periodontal diseases. Thanks to the improved understanding of the pathogenesis of periodontal disease, which involves the host immune response, and the importance of the human microbiome, the primary goal of periodontal therapy has shifted, in recent years, to the restoration of homeostasis in oral microbiota and its harmonious balance with the host periodontal tissues. This shift in therapeutic goals and the drug resistance challenge call for alternative approaches to antibiotic therapy that indiscriminately eliminate harmful or beneficial bacteria. In this review, we summarize the recent advancement of alternative methods and new compounds that offer promising potential for the treatment and prevention of periodontal disease. Agents that target biofilm formation, bacterial quorum-sensing systems and other virulence factors have been reviewed. New and exciting microbiome approaches, such as oral microbiota replacement therapy and probiotic therapy for periodontal disease, are also discussed.

α-Cyperone Ameliorates Lipopolysaccharide-Induced Inflammation and Apoptosis of Periodontal Ligament Stem Cells via Blocking the Toll-Like Receptor 4/NF-κB Signaling

Periodontitis is a long-lasting inflammatory microbial sickness that could cause damage to the periodontal ligament, gums, cementum and alveolar bone directly. Cyperus rotundus is a common traditional Chinese medicine clinically with many pharmacological activities, α-Cyperone is a bioactive ingredient abundant in Cyperus rotundus, few studies have focused on its anti-fungal and anti-oxidative stress activities in mice, during this research, we firstly investigated the impact of α-Cyperone on PDLSCs inflammatory by LPS stimulation. Our findings illustrated that α-Cyperone exerted no influence on PDLSCs viability at concentrations lower than 60 μM, and the release of inflammatory cytokines decreased with an increase in LPS concentration. Meanwhile, we found that α-Cyperone effectively restrained LPS-induced PDLSC cell apoptosis by CCK-8 cell viability assay and TUNEL-positive staining. Furthermore, the TLR4 expression and NF-κB kinase activation were greatly repressed by α-Cyperone treatment in LPS-induced PDLSCs inflammatory model. Subsequently, enhanced TLR4 expression was observed to reverse the suppressed release of inflammatory cytokines and decreased apoptosis effects mediated by α-Cyperone in LPS-cotreated PDLSCs, indicating that the deactivation of TLR4 and downstream NF-κB were implicated in favoring α-Cyperone-triggered protective effects of LPS in PDLSCs.