Investigation of multipotent postnatal stem cells from human periodontal ligament

Roles of Piezo1 in chronic inflammatory diseases and prospects for drug treatment (Review)

The human body is chronically stimulated by various mechanical forces and the body cells can sense harmful stimuli through mechanotransduction to induce chronic inflammation. Piezo type mechanosensitive ion channel component 1 (Piezo1), a novel transmembrane mechanosensitive cation channel, is widely expressed in inflammatory cells, such as neutrophils, macrophages and endothelial cells, as well as in non‑inflammatory cells, such as osteoblasts, osteoclasts and periodontal cells. A growing number of studies have demonstrated that Piezo1 senses changes in environmental mechanical forces, regulates cellular functions and influences the development and regression of chronic inflammation. The present study summarized the roles of Piezo1 and its possible mechanisms in some common chronic inflammatory diseases and evaluated the potential application of drugs that modulate its activity, so as to prove that Piezo1 is likely to become a new target for the treatment of inflammatory diseases.15.

The paradigm shifts of periodontal regeneration strategy: From reparative manipulation to developmental engineering

Ideal periodontal regeneration requires the integration of alveolar bone, periodontal ligament, and cementum, along with Sharpey's fibers for occlusal force resistance. However, physiological regeneration remains rare due to its intricate structure, making clinical regeneration a challenge. Periodontal ligament stem cells (PDLSCs), first isolated in 2004, hold the key to multi-directional differentiation into cementoblasts, fibroblasts, and osteoblasts. While traditional therapies like guided tissue regeneration (GTR) aim to activate PDLSCs, clinical outcomes are inconsistent, suggesting the need for additional strategies to enhance PDLSCs' functions. Advancements in molecular biotechnology have introduced the use of recombinant growth factors for tissue regeneration. However, maintaining their efficacy requires high doses, posing cost and safety issues. Multi-layered scaffolds combined with cell sheet technology offer new insights, but face production, ethical, and survival challenges. Immune regulation plays a crucial role in PDLSC-mediated regeneration. The concept of "coagulo-immunomodulation" has emerged, emphasizing the coupling of blood coagulation and immune responses for periodontal regeneration. Despite its potential, the clinical translation of immune-based strategies remains elusive. The "developmental engineering" approach, which mimics developmental events using embryonic-stage cells and microenvironments, shows promise. Our research group has made initial strides, indicating its potential as a viable solution for periodontal complex regeneration. However, further clinical trials and considerations are needed for successful clinical application. This review aims to summarize the strategic transitions in the development of periodontal regenerative materials and to propose prospective avenues for future development.

Diagnostic and therapeutic potential of oral cavity-derived exosomes in oral and maxillofacial tissue engineering: current advances and future perspectives

Oral and maxillofacial (OMF) tissue engineering has always been the subject of longstanding professional and academic debates. Despite rapidly evolving therapeutic approaches including reconstructive surgeries, tissue grafts, platelet-rich therapies, and mesenchymal stem cell-based treatments, there are remaining concerns regarding the therapeutic efficacy, safety profile, immunological compatibility, target-specificity, and ethical issues of such therapies. In addition to the multifactorial nature of OMF diseases, complex maxillofacial anatomy and neurovasculature further pinpoint the urgent need for breakthroughs in the era of OMF treatments. In recent years, exosomes have garnered immense popularity as the frontiers of regenerative medicine. Exosomes, natural nanovesicles secreted by a wide range of cells, act as nano messengers that harbor the rich molecular cargo received by their original cells and demonstrate important roles for diverse physiological and pathological intercellular communications. Among the different sources of exosomes, the oral cavity hosts a wide variety of mesenchymal stem cell-derived and salivary exosomes. Owing to the neural crest origin and multipotent differentiation, oral stem cell-derived exosomes hold great promise for OMF tissue engineering. Moreover, exosomes derived from pathological oral cavity cells and saliva samples provide diagnostic and prognostic signatures for different OMF diseases. This review highlights the cutting-edge diagnostic and therapeutic applications of oral cavity-derived exosomes in the field of OMF regeneration. Furthermore, we emphasize the existing challenges and constraints in exosome-based diagnostics and therapy, thus offering important perspectives for the future clinical application of exosomes derived from the oral cavity.

Comparative Dental Pulp Stem Cells (DPSCs) and Periodontal Ligament Stem Cells (PDLSCs): Difference in effect of aspirin on osteoblast potential of PDLSCs and DPSCs

Periodontal Ligament Stem Cells (PDLSCs) and Dental Pulp Stem Cells (DPSCs) are mesenchymal stem cells with the ability to self-renew and differentiate into three lineages. One significant advantage of dental stem cells, such as PDLSCs and DPSCs, is their ease of harvest compared to other types of mesenchymal stem cells (MSCs). While MSCs are highly valued in bone tissue engineering, MSCs sourced from dental tissues, such as PDLSCs and DPSCs, offer promising options for periodontal regeneration because they are more easily accessible and can be collected through minimally invasive methods. Currently, PDLSCs and DPSCs exhibit a strong ability to undergo osteogenic differentiation when stimulated by factors such as growth factors, chemicals, and paracrine signaling. It has been shown that aspirin (ASA) can enhance the osteoblastic potential of PDLSCs and DPSCs, although the exact mechanism remains unclear. This article examines the origin and features of mesenchymal stem cells, the bone regeneration potential of DPSCs and PDLSCs, the factors that enhance their osteogenic differentiation, and a comparison of PDLSCs and DPSCs regarding their proliferation and differentiation abilities. Additionally, we will examine the effects of aspirin on PDLSCs and DPSCs. In conclusion, PDLSCs show a greater effect on osteoblast differentiation.

The effects of FOXC2-gene-manipulated human periodontal ligament stem cells on bone regeneration of craniofacial bone defect

The progress and development of bone tissue engineering technology has brought new hope for the repair of oral and maxillofacial bone defects. As one of the ideal seed cells, the induction of human periodontal ligament stem cells (hPDLSCs) into osteoblasts has become a focus in current research. Forkhead box C2 (FOXC2) may be a good candidate gene for bone regeneration. Therefore, the aim of this study was to verify the role of FOXC2 in hPDLSCs osteogenesis and genetically-manipulate seed cells based on FOXC2 gene for enhancing their bone regeneration potentials. The hPDLSCs models with down-regulated and up-regulated expression of FOXC2 were constructed by lentivirus transfections. ALP staining, alizarin red staining, qRT-PCR, WB analysis and histological staining were used to verify the function of FOXC2 in regulating osteogenic differentiation of hPDLSCs. Finally, through transcriptome sequencing and qRT-PCR verification, the downstream core genes, and possible mechanism of FOXC2 were speculated. All data were presented as means ± standard deviations (SDs). P values less than 0.05 were considered statistically significant. GraphPad PRISM software (version 9.0; La Jolla, CA, USA) was used. The research results suggest that FOXC2 gene is involved in the regulation of osteogenic differentiation of hPDLSCs which may be related to promoting extracellular matrix interaction, cell adhesion and collagen formation. hPDLSCs with FOXC2 up-regulation are expected to be used as gene-enhanced seed cells in bone tissue engineering.

Klotho senses mechanical stimuli and modulates tension-induced osteogenesis

Delicate external mechanosensing, efficient intracellular mechanotransduction and effective alveolar bone remodeling lay the foundation of orthodontic tooth movement (OTM). Periodontal ligament stem cells (PDLSCs) are thought to be the primary cells that withstand mechanical stimuli and respond to biomechanical signals during orthodontic treatment. Nevertheless, the cellular and molecular mechanisms of orthodontic force-induced mechanosignaling and osteogenesis in PDLSCs still remain unclear. In the present study, we hypothesize that the ageing suppressor, Klotho, is correlated with orthodontic force-triggered mechanical signaling cascades, further contributing to alveolar bone remodeling. This study reveals that Klotho expression is notably upregulated via cytoskeletal-nuclei-mediated epigenetic modifications, consistent with osteogenic differentiation on the tension side during OTM. Additionally, Klotho deficiency undermines tensile force-induced new bone formation in NFκB- and PI3K/Akt-dependent manners. Notably, RNA sequencing (RNA-seq) results and targeted force application experiments unveil that Klotho not only functions as a downstream effector of external stress but also acts as an upstream regulator in mechanical signaling for the first time. In summary, we identify the indispensable role of Klotho in mechanotransduction and alveolar bone formation, which provide a latent target of linking cell senescence to mechanical force in future studies and offer novel insights into orthodontic force-induced tooth movement and bone remodeling.

The Biological Role of the Signal Transducer and Activator of Transcription 1 (STAT1)-miR-221/222-3p-p21 Activated Kinase 1 (PAK1) Axis in Experimental Periodontitis

Periodontitis is a chronic inflammatory disease characterized by the progressive destruction of tooth-supporting tissues. Despite extensive research, the molecular mechanisms underlying its pathogenesis remain incompletely understood. This study aimed to investigate the role and regulatory mechanisms of miR-221/222-3p in experimental periodontitis. The expression of miR-221/222-3p in lipopolysaccharide (LPS)-stimulated periodontal ligament cells (PDLCs) and ligation-induced rat periodontitis were detected by RT-qPCR. miR-221/222-3p agomir were administrated topically in ligation-induced rat periodontitis. The therapeutic function of both miRNAs were assessed by micro-CT, TRAP staining, and immunohistochemistry. The mechanisms of miR-221/222-3p function in periodontitis were determined by cell assays. miR-221-3p and miR-222-3p expression were both downregulated in LPS-stimulated PDLCs and ligation-induced periodontitis rat. In vitro, miR-221-3p and miR-222-3p could alleviate the inflammatory damage of PDLCs upon LPS stimulation. Mechanically, PAK1 is demonstrated as a target gene of miR-221/222-3p. Additionally, STAT1 signaling pathway is activated by LPS treatment and STAT1 could bind to the upstream region of the miR-221/222-3p promoter and repress their expression. In vivo, miR-221/222-3p agomir rescued the alveolar bone loss, alleviated the infiltration of osteoclasts and the expression of inflammatory cytokines of periodontitis rats. Our results revealed a novel STAT1-miR-221/222-3p-PAK1 axis in the initiation and progression of periodontitis. Specific targeting this signaling pathway may provide a new therapeutic avenue for periodontitis.

Circular RNAs inducing the osteogenic differentiation of dental mesenchymal stem cells via microRNA sponging

Circular RNAs (circRNAs) are a distinct type of nonlinear and noncoding RNAs endogenously expressed by pre-mRNA back-splicing and crucial in transcriptional and posttranscriptional regulation. CircRNAs can regulate cellular and molecular pathways through various mechanisms, such as microRNA sponging. Numerous studies have indicated the regulatory roles of circRNAs in the osteogenic differentiation of stem cells (SCs) isolated from different sources. Dental tissue-derived mesenchymal SCs (MSCs) have received considerable attention in artificial bone engineering, in which SCs are used to manufacture functional bone tissues to repair bone defects. Recently, studies have reported the regulatory roles of circRNAs in the osteogenic differentiation of dental-derived MSCs, such as apical papillae, dental pulp, and dental follicle SCs. This review aimed to discuss the findings of studies evaluating the contribution of circRNAs to the osteogenic differentiation of dental-derived MSCs.

Incorporation of Zinc Oxide Nanoparticles Biosynthesized from Epimedium brevicornum Maxim. into PCL Nanofibers to Enhance Osteogenic Differentiation of Periodontal Ligament Stem Cells

The optimal parameters for the microwave-assisted extraction of Epimedium brevicornum Maxim. were determined by using response surface methodology (RSM), increasing the extraction of flavonoids by 1.79 times. The resulting extract facilitated the green synthesis of zinc oxide nanoparticles (ZnONPs) with a wurtzite structure through a reaction with zinc nitrate. These ZnONPs were then incorporated into polycaprolactone (PCL) by using an electrospinning technique to produce nanofibers. The incorporation of ZnONPs resulted in an increase in Young's modulus, biodegradation rate, and swelling ratio while decreasing the diameter and water contact angle of the nanofibers, thereby improving the hydrophilicity of PCL. ZnO demonstrates excellent biocompatibility with periodontal ligament stem cells (PDLSCs), increasing cell proliferation and enhancing alkaline phosphatase activity by 56.9% (p < 0.05). Additionally, mineralization deposition increased by 119% (p < 0.01) in the presence of 1% ZnO and showed a concentration-dependent response. After inducing PDLSC cultures with PCL-1% ZnO for 21 days, the protein expression levels of Runx2 and OCN increased by 50% (p < 0.05) and 30% (p < 0.001), respectively. Additionally, Col-1, Runx2, BSP, and OCN gene expression levels increased by 2.18, 1.88, 1.8, and 1.7 times, respectively. This study confirms that biosynthesized ZnONPs improve the physical properties of PCL nanofibers and effectively induce the osteogenic differentiation of PDLSCs.

Branched-chain amino acids promote gelatinase secretion from human periodontal ligament stem cells through nuclear factor kappa-B signaling

OBJECTIVE

To explore the effects of branched-chain amino acids (BCAAs) on periodontal tissues and regulation of gelatinase secretion by human periodontal ligament stem cells (hPDLSCs).

DESIGN

The salivary BCAA levels (leucine, isoleucine, and valine) in the clinical participants were measured using mass spectrometry. A local injection model in the periodontium of Sprague Dawley rats was established to investigate the periodontal destruction induced by BCAAs. A BCAA-treatment model of hPDLSCs was established to detect the expression and activity of gelatinase and further explore the potential mechanism by which BCAAs enhance gelatinase secretion.

RESULTS

Compared to the healthy controls, the salivary levels of leucine (p = 0.0190), isoleucine (p = 0.0351), and valine (p = 0.0072) were significantly elevated in individuals with periodontitis. In vivo experiments revealed that BCAAs aggravated periodontal extracellular matrix degradation and alveolar bone resorption in rats. Three-dimensional reconstruction of the rat maxilla demonstrated an increase in the distance from the cementoenamel junction to the alveolar bone crest (p < 0.0001), and a decrease in the bone volume fraction (p < 0.0001). In vitro experiments demonstrated that BCAAs activate the phosphorylation of nuclear factor kappa-B (NF-κB) signaling pathway in the hPDLSCs and consequently induce the secretion of gelatinases. The absence of any of the components in the BCAAs attenuated this effect.

CONCLUSION

BCAAs increase gelatinase secretion through the NF-κB (p-p65) signaling pathway, consequently exacerbating periodontal tissue destruction. This provides a novel insight on the role of BCAAs in the host immune-inflammatory response and increases our understanding of the possible involvement of BCAAs in the periodontitis development.

The role of autophagy in periodontal diseases: a bibliometric analysis from 2006 to 2023

Background

Periodontal disease is a chronic inflammatory condition affecting the supporting structures of the teeth, involving complex interactions between systemic and local immune responses. Autophagy is a tightly regulated cellular process that is responsible for degrading and recycling cellular components, playing a pivotal role in maintaining cellular homeostasis and modulating inflammation in periodontal disease. In recent years, the relationship between these two factors has attracted attention from scholars globally. However, bibliometric analyses in this field are still limited.

Objectives

To analyze the bibliometric trends and research hotspots related to the role of autophagy in periodontal disease.

Methods

Articles and reviews examining the association between periodontal disease and autophagy were retrieved from the Web of Science Core Collection (WOSCC) on 20 June 2024. Bibliometric and knowledge mapping analyses were performed using CiteSpace [6.3. R1 (64-bit) Advanced].

Results

Through a bibliometric analysis of literature published between 2006 and 2023 on the role of autophagy in periodontal disease, 341 relevant studies were identified. The results indicate a steady annual increase in studies on this topic, with a significant upward trend observed post-2015. Keyword analysis identifies "apoptosis," "Porphyromonas gingivalis," "oxidative stress," "inflammation," "periodontitis," "osteogenic differentiation," "cell death," and "orthodontic tooth movement" as key research hotspots. Collaboration network analysis identifies China as the leading contributor to research in this field. Document co-citation analysis highlights several influential studies examining the "double-edged sword" role of autophagy in periodontal disease, illustrating how autophagy alleviates oxidative stress and inflammation in periodontitis by removing damaged organelles, inhibiting pro-inflammatory mediators, and promoting periodontal tissue repair through the secretion of pro-angiogenic cytokines. However, excessive autophagy may lead to apoptosis when cellular stress surpasses the repair capacity. This study identifies key trends and research hotspots in autophagy and periodontal disease, underscoring the importance of international collaboration and high-impact journals for advancing the field and guiding future research.

Conclusion

Recent studies indicate that autophagy has emerged as a critical mediator with dual roles in periodontal disease. Therefore, early control of periodontal inflammation, along with the exploration of how to harness the protective functions of autophagy, may provide future research directions for managing periodontal disease.

Impacts of Circular RNAs on the Osteogenic Differentiation of Dental Stem Cells

Dental stem cells are widely viewed as good options for bone regeneration because of their ease of acquisition, innate ability to renew themselves, and ability to differentiate into different types of cells. However, the process of osteogenic differentiation of dental stem cells is orchestrated by an intricate system of regulatory mechanisms. Recent studies have demonstrated the critical impacts of circular RNAs (circRNAs) on osteogenic differentiation of dental stem cells. Exploring the roles and regulatory pathways of circRNAs in dental stem cells could identify novel targets and approaches for utilizing dental stem cell therapy in clinical settings. This review provides a comprehensive overview of the functions and mechanisms of circRNAs, with a particular focus on their expression patterns and regulatory roles in osteogenic differentiation of various dental stem cell types. Furthermore, this review discusses current research challenges in this field and proposes future directions for advancing our understanding of circRNA-mediated regulation in dental stem cell biology.

Combination of Periodontal Ligament Stem Cells and Metformin via Organic Cation Transporters for Periodontal Regeneration in Rats

Periodontal regeneration remains challenging due to individual variability, especially in treatments involving bioactive factors such as metformin. This study aimed to investigate the role of organic cation transporters (OCTs) in metformin-induced periodontal regeneration. The expression and function of OCTs in human periodontal ligament stem cells (hPDLSCs) were assessed, and OCT-mediated metformin uptake was quantified by high-performance liquid chromatography (HPLC). Osteogenic and cementogenic differentiation markers were analyzed in vitro, and periodontal regeneration was evaluated using a rat periodontal defect model. OCTs were differentially expressed and functional in hPDLSCs. Both the OCT1 inhibitor cimetidine and OCT1 knockdown significantly reduced intracellular metformin accumulation to 50-60% and 20-30% of control levels, respectively (p < 0.01). Cimetidine diminished the osteogenic and cementogenic effects of metformin by approximately 31-48% and 32-40%, respectively (p < 0.01). In vivo, oral administration of cimetidine decreased bone regeneration by 25% and cementum regeneration by 36% compared with controls receiving GelMA/hPDLSCs/metformin (p < 0.01). This study demonstrates that OCTs regulate metformin uptake in hPDLSCs, and that inhibition of OCT1 by cimetidine significantly reduces the osteogenic and cementogenic efficacy of metformin, providing the first evidence of drug interactions affecting periodontal regeneration mediated by OCT transport in rats.

Induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) inhibit M1 macrophage polarization and reduce alveolar bone loss associated with periodontitis

BACKGROUND

Periodontitis is a chronic inflammatory disease and macrophages play a pivotal role in the progression of periodontitis. Mesenchymal stem cells (MSCs) have emerged as potential therapeutic agents for the treatment of periodontitis due to their immunomodulatory properties and capacity for tissue regeneration. Compared to conventionally derived MSCs, induced pluripotent stem cell-derived MSCs (iMSCs) offer distinct advantages as promising candidates for MSC-based therapies, owing to their non-invasive acquisition methods and virtually unlimited availability. This study aims to investigate the effects and mechanisms of iMSCs in modulating macrophage polarization and alleviating periodontitis-related alveolar bone loss.

METHODS

iMSCs were generated from iPSCs and characterized for differentiation potential. The effects of iMSCs on macrophage polarization were evaluated using THP-1-derived macrophages under inflammatory conditions (LPS and IFN-γ stimulation). Co-culture assays, cytokine analysis, reactive oxygen species (ROS) detection, transcriptomic analysis, flow cytometry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blot analysis were performed to elucidate the underlying mechanisms. The therapeutic potential of iMSCs was assessed in a ligature-induced periodontitis mouse model using micro-CT, histological analysis, and immunofluorescence staining.

RESULTS

iMSCs inhibit M1 macrophage polarization through the suppression of the NF-κB signaling pathway. Additionally, iMSCs reduce the production of pro-inflammatory cytokines (IL-1β, IL-17) and reactive oxygen species (ROS), while enhancing the secretion of anti-inflammatory cytokines (IL-10) and growth factors (VEGF), thereby improving the inflammatory microenvironment. Under inflammatory conditions, iMSCs preserve the osteogenic potential of periodontal ligament stem cells (PDLSCs) and alleviate alveolar bone loss in mice with periodontitis. In vivo, iMSCs reduce the number of M1 macrophages and inhibit the activation of NF-κB in periodontal tissues, supporting their anti-inflammatory and immunomodulatory effects.

CONCLUSION

iMSCs demonstrate significant therapeutic potential in periodontitis by modulating macrophage polarization, reducing oxidative stress, and mitigating alveolar bone loss associated with the disease. These findings provide new insights into the mechanisms of iMSCs and their application as cell-based therapies for periodontal diseases.

Gastrointestinal cholecystokinin signaling pathway drugs modulate osteogenic/cementogenic differentiation of human periodontal ligament stem cells

OBJECTIVES

Understanding the complexities of periodontal regeneration, particularly the unpredictable osteogenic/cementogenic differentiation of low-potential PDLSCs (LOP-PDLSCs), remains challenging. Identifying new therapeutic targets is crucial for enhancing regeneration. This study investigates the modulation of the Cholecystokinin (CCK) pathway, a key signaling cascade with roles in the gastrointestinal system, as a potential osteogenic/cementogenic pathway in PDLSCs.

METHODS

Gastrointestinal CCK-related drugs, Lorglumide and Sincalide, were tested for their effects on mineralization in PDLSCs. Lorglumide blocked the CCK pathway in high-potential PDLSCs (HOP-PDLSCs), while Sincalide enhanced mineralization in low-potential PDLSCs (LOP-PDLSCs). Cellular viability was tested under different drug concentrations, followed by a mineralization assay (AR-S) using non-toxic doses. RT-qPCR for osteogenic-related genes (IGF1, OCN, RUNX2) and CCK pathway-related genes (CCK, CCKAR, CCKBR, COX2, FOS, JNK3, RGS2) assessed gene modulation. Alkaline phosphatase (ALP) activity, Ca²⁺ quantification, and IP3 receptor phosphorylation were also evaluated.

RESULTS

Lorglumide reduced mineralization, ALP activity, and RUNX2, OCN, and IGF1 transcripts in HOP-PDLSCs (p < 0.05). It decreased CCK and CCKAR expression, modulated COX2, FOS, JNK3, and RGS2 genes, reduced IP3 receptor phosphorylation, and lowered calcium levels (p < 0.05). Conversely, Sincalide enhanced mineralization in LOP-PDLSCs, increasing ALP activity and OCN and IGF1 expression (p < 0.05). It upregulated COX2, FOS, JNK3, and RGS2 genes, phosphorylated IP3 receptors in LOP1, and increased calcium levels in all LOP-PDLSCs (p < 0.05).

CONCLUSIONS

Sincalide and Lorglumide modulate PDLSCs' osteogenesis/cementogenesis, revealing the complex interplay of gastrointestinal drugs in periodontal tissue regeneration and offering insights for innovative therapies.

CLINICAL SIGNIFICANCE

This study demonstrates the potential of gastrointestinal drugs targeting the CCK signaling pathway as innovative modulators for periodontal regeneration. By regulating osteogenic/cementogenic differentiation in hPDLSCs, these findings may pave the way for the development of novel biomaterials and therapies, promising improved outcomes in periodontal tissue regeneration for clinical applications.

Human periodontal ligament stem cells and metformin to enhance periodontal regeneration in rats

BACKGROUND

Effective periodontal repair and regeneration remain a critical clinical need, requiring strategies that address the complex regeneration of both bone and cementum within the periodontal complex. The objectives of this study were to: (1) develop a novel strategy for periodontal regeneration via human periodontal ligament stem cells (hPDLSCs) and metformin; (2) investigate the metformin regulatory mechanism via the ERK1/2 signaling pathway that promotes periodontal regeneration; (3) evaluate the effectiveness of the combination of hPDLSCs and metformin in promoting the repair of periodontal defects in rats.

METHODS

hPDLSCs were cultured in medium with graded metformin doses (0-600 μM) to determine the optimal concentration via CCK-8 assay, scratch assay and osteogenic/cementogenic differentiation analyses. ERK1/2 phosphorylation, induced by the optimal metformin concentration, and its inhibition by U0126 (10 μM) were analyzed via Western blot to assess its role in promoting osteogenesis and cementogenesis. In vivo, 30 rats with periodontal defects were divided into five groups: (1) Blank control; (2) Matrigel only; (3) Matrigel + metformin; (4) Matrigel + hPDLSCs; (5) Matrigel + Metformin + hPDLSCs. Micro-CT and histological staining were performed at 6 weeks to evaluate periodontal regeneration. Data were analyzed using one-way and two-way ANOVA (p < 0.05).

RESULTS

100 μM metformin optimally promoted hPDLSCs proliferation, migration, osteogenesis, and cementogenesis, with ALP activity and mineralization increased by 5-fold and 17-fold, respectively, and cementogenic gene expression upregulated to 6-8 times control levels (p < 0.05). The MEK1/2 inhibitor (U0126) decreased metformin's impact on osteogenesis and cementogenesis by 40-50 % (p < 0.05). Compared to the control group, Matrigel+Met+hPDLSCs group enhanced bone regeneration by 3.6 folds, and increased cemental regeneration by 9.5 folds in rats (p < 0.05).

CONCLUSION

This study focused on the dual role of metformin-hPDLSCs combination in promoting both osteogenesis and cementogenesis, addressing the specific needs of periodontal complex regeneration. Additionally, the ERK1/2 signaling is involved in the metformin-induced osteogenesis and cementogenesis.

The photobiomodulation effects of continuous and pulsed blue diode laser on proliferation and osteogenic differentiation of periodontal ligament stem cells

This study investigated the photobiomodulation effect of pulsed and continuous blue diode laser on osteogenic differentiation and proliferation of periodontal ligament mesenchymal stem cells. Periodontal Ligament Stem cells were seeded in 96-well plates, and 450 nm blue laser irradiation procedure was performed a day after cell seeding. Each experimental group was divided into two subgroups according to their energy density and irradiation duration: Continuous wave (100 mW, 10s, 2 J/cm2 and 100 mW, 20 s, 4 J/cm2) and pulse wave (200 mW, 10 s, 2 J/cm2 and 200 mW, 20 s, 4 J/cm2 and duty cycle 50% for both). Then, all groups were evaluated with a cell viability test (MTT), cell apoptosis (Annexin V) on the second and fourth days after irradiation, Alizarin Red staining on the 14th day after irradiation based on genes. Real-time PCR was conducted 7 and 14 days after irradiation. GAPD gene primers were used as internal control, and OPN, OCN, ALP, and RUNX2 gene primers were used as tests. The one-way ANOVA statistical analysis revealed that cell proliferation in the continuous-irradiated groups was significantly higher than in pulsed groups. However, there is no significant difference in comparison with the control group. Also, pulsed-irradiated groups demonstrated a higher rate of necrosis. The osteogenic differentiation in the continuous groups was more substantial than in the pulsed and the control groups. In comparison to all other study groups, the group that received continuous mode irradiation at an energy density of 2 J/cm2, power of 100 mW, and a radiation time of 10 s exhibited significantly higher numbers of calcified nodules and increased expression of OPN, OCN, and ALP genes (p < 0.05). Overall, treating periodontal ligament stem cells with a continuous blue diode laser and appropriate parameters can enhance their osteogenic differentiation and proliferation, accelerating the regeneration of periodontal tissues.

Influence of Tooth Maturity on Healing Outcomes in Regenerative Endodontics

Regenerative endodontic procedures using blood clots (BC-REP) for immature teeth typically exhibit a periodontal ligament-like healing pattern. However, a pulp-like healing pattern is observed in the presence of residual pulp. This study aimed to clarify the healing phenotype according to tooth maturity when performing BC-REP in the presence of residual pulp, focusing on migrated mesenchymal stem/stromal cells (MSCs). BC-REP rat molar models were created in the presence of residual pulp at ages corresponding to tooth developmental stages, from immature to mature (5 wk: immature, root is still growing; 8 wk: near mature, root has finished growing in length but the apex is not formed; 11 wk: mature, the apex is formed). The healing pattern and histological MSC markers (α-smooth muscle actin [α-SMA], CD73, CD90, and CD146) were investigated. The frequency of periodontal ligament-like healing was higher in mature teeth than in immature teeth. In addition, more healing macrophages were observed at the apical site 28 d after BC-REP, which is the final stage of healing. In immature teeth, double-immunopositive cells for proliferation markers (ki67 and proliferating cell nuclear antigen [PCNA]) and α-SMA were frequently observed in the vicinity of the root canal orifice 7 d after treatment, which is the early stage of healing. By contrast, in mature teeth, the number of CD73-, CD90-, and CD146-immunopositive cells increased at the apical site after 7 and 28 d. CD90- and CD146-immunopositive cells expressed cell proliferation markers (ki67 or PCNA) after 7 d. MSC migration after BC-REP likely varies based on tooth maturity, resulting in different healing phenotypes.

Engineered 3D mesenchymal stem cell aggregates with multifunctional prowess for bone regeneration: Current status and future prospects

BACKGROUND

Impaired efficacy of in vitro expanded mesenchymal stem cells (MSCs) is a universal and thorny situation, which cast a shadow on further clinical translation of exogenous MSCs. Moreover, the relatively lengthy healing process, host metabolic heterogeneity and the sophisticated cell recognition and crosstalk pose rigorous challenges towards MSC-based bone regeneration strategies. Three-dimensional (3D) cell aggregates facilitate more robust intercellular communications and cell-extracellular matrix (ECM) interactions, providing a better mimicry of microarchitectures and biochemical milieus in vivo, which is conducive for stemness maintenance and downstream bone formation.

AIM OF REVIEW

This review enunciates the phenotypic features of MSCs in aggregates, which deepens the knowledge of the MSC fate determination in 3D microenvironment. By summarizing current empowerment methods and biomaterial-combined techniques for establishing functionalized MSC aggregates, this review aims to spark innovative and promising solutions for exalting the translational value of MSCs and improve their therapeutic applications in bone tissue repair.

KEY SCIENTIFIC CONCEPTS OF REVIEW

3D aggregates optimize regenerative behaviors of in vitro cultured MSCs including cell adhesion, viability, proliferation, pluripotency and immunoregulation capacity, etc. Biomaterials hybridization endows MSC aggregates with tailored mechanical and biological properties, which offers more possibilities in adapting various clinical scenarios.

Assessment of Physical Properties, Obturation Quality, and Cytocompatibility/Osteogenic Potential of KP-Root SP: A New Calcium Silicate-based Bio-ceramic Sealer

INTRODUCTION

The study aims to evaluate the physical properties, obturation quality, biocompatibility, and osteogenic induction characteristics of KP-Root SP with iRoot SP.

METHODS

The evaluation of flow, film thickness, radiopacity, and solubility was conducted according to ISO 6876 Dentistry-Root Canal Sealing Materials. Forty isolated premolars, after preparation, were numbered and randomly assigned into 2 groups, and root-filled using size-fitted gutta-percha master cones along with KP-Root SP or iRoot SP sealers. Micro computed tomography (Micro-CT) scans were performed pre- and postobturation, and reconstructed images were analyzed to determine the volumetric percentage of the filling materials. After setting, the sealers' microstructure and composition were analyzed using light microscopy, scanning electron microscopy, and energy dispersive spectroscopy. The release of silicon, calcium, and strontium ions were identified using inductively coupled plasma mass spectrometry. Cell proliferation, inflammatory cytokine production (interleukin-4 (IL-4), interleukin-6 (IL-6), and interleukin-8 (IL-8)), and osteogenic potential were examined in human periodontal ligament cells (hPDL cells) exposed to KP-Root SP or iRoot SP.

RESULTS

Both KP-Root SP and iRoot SP comply with the ISO 6876:2012 standard regarding flow, film thickness, radiopacity, and solubility. The 2 groups demonstrated 84%-95% canal space occupancy with root filling material. No notable differences were observed in the entire root canal, as well as in the apical and middle thirds. The KP-Root SP group contained a greater average volume of filling material in the coronal third than the iRoot SP group. Microscopic images and scanning electron microscopy analyses revealed that both materials exhibited no obvious gaps with dentin or gutta-percha, indicating good sealing properties. Both iRoot SP and KP-Root SP contain similar core elements in varying proportions. Additionally, KP-Root SP includes strontium. iRoot SP and KP-Root SP extracts at a concentration of 20 mg/mL have no cytotoxic effects on hPDL cells at both 24 and 48 hours. While iRoot SP and KP-Root SP promoted the release of IL-4 to induce an anti-inflammatory response, they also triggered increases in IL-6 and IL-8, reflecting a proinflammatory response. Both iRoot SP and KP-Root SP enhanced the osteogenic potential of hPDL cells.

CONCLUSIONS

The results demonstrate that KP-Root SP and iRoot SP show no significant differences in terms of physical properties, obturation quality, cytocompatibility, and osteogenic potential.

Role of exosomes in dental and craniofacial regeneration - A review

BACKGROUND

The treatment of congenital deformities, traumatic injuries, infectious diseases, and tumors in the craniomaxillofacial (CMF) region is complex due to the intricate nature of the tissues involved. Conventional treatments such as bone grafts and cell transplantation face limitations, including the need for multiple surgeries, complications, and safety concerns.

OBJECTIVE

This paper aims to provide a comprehensive analysis of the role of exosomes (EXOs) in CMF and dental tissue regeneration and to explore their potential applications in regenerative dental medicine.

METHODS

An extensive review of advancements in tissue engineering, materials sciences, and nanotechnology was conducted to evaluate the development of delivery systems for EXOs-based therapies. The analysis included how EXOs, as nanovesicles released by cells, can be modified to target specific cells or loaded with functional molecules for drug or gene delivery.

RESULTS

EXOs have emerged as a promising alternative to cell transplant therapy, offering a safer method for cell communication and epigenetic control. EXOs transport important proteins and genetic materials, facilitating intercellular communication and delivering therapeutics effectively. The potential of EXOs in personalized medicine, particularly in diagnosing, customizing treatment, and predicting patient responses, is highlighted.

CONCLUSION

EXO-mediated therapy holds significant potential for advancing tissue regeneration, offering targeted, personalized treatment options with reduced side effects. However, challenges in purification, production, and standardized protocols need to be addressed before its clinical application can be fully realized.

Modified Hank's Balanced Salt Solution as a Storage Medium for Avulsed Teeth: In Vitro Assessment of Periodontal Fibroblast Viability

BACKGROUND/AIM

The optimal storage medium for an avulsed tooth should preserve the viability of periodontal fibroblasts (PDLF) to the highest degree, facilitating the re-attachment of periodontal fibers and improving the prognosis of replantation. This study compared the effect of the PDLF viability in Hank's balanced salt solution (HBSS), supplemented culture medium, that is, Dulbecco's Modified Eagle Medium (DMEM), and four modified HBSS mixtures.

MATERIAL AND METHODS

Periodontal tissues were obtained from extracted human teeth and processed for PDLF culture. The cells were then exposed to six experimental media: (i) HBSS, (ii) HBSS and ascorbic acid (HBSS + Vit C), (iii) HBSS and platelet-derived growth factor (HBSS + PDGF), (iv) a mixture of HBSS, PDGF, and Vit C (HBSS + PDGF + Vit C), (v) HBSS and platelet lysate (HBSS + PL), and (vi) DMEM for 3, 6, 12, and 24 h. A MTT assay was performed to determine the cell viability.

RESULTS

Vitamin C-containing media maintained PDLF viability significantly better than HBSS + PDGF and HBSS + PL at 3, 6, 12, and 24 h (p < 0.05). The percentages of viable PDLF at 3, 6, 12, and 24 h were significantly higher than 0 h for HBSS + Vit C, HBSS + PDGF + Vit C, HBSS + PL, and DMEM (p < 0.05).

CONCLUSION

All experimental media were able to maintain PDLF viability (DMEM>HBSS+Vit C; HBSS+PDGF+Vit C>HBSS+PL>HBSS+PDGF; HBSS). Although DMEM had the highest cell proliferative effect, it is impractical to be used as a transport medium due to its cost, storage, and availability. The supplementation of Vit C yielded significant cell proliferative effects; hence, HBSS + Vit C can be a better alternative as a storage medium than HBSS.

The relationship between MAPK signaling pathways and osteogenic differentiation of periodontal ligament stem cells: a literature review

Periodontitis is a common oral disease that can lead to gingival inflammation, development of periodontal pockets, resorption of the alveolar bone, and the loosening and eventual loss of teeth. The optimal outcome of periodontitis treatment is maximum regeneration and functional reconstruction of periodontal tissues after control of infection and elimination of inflammation. Since both the self-healing ability of alveolar bone and the efficacy of traditional treatment methods are very limited, stem cell-based tissue regeneration engineering has received more and more attention from scholars. The best cells for periodontal tissue regeneration have been well examined, and these are called periodontal ligament stem cells (PDLSCs). The MAPK signaling pathways, including the ERK1/2, p38 MAPK, JNK, and ERK5 signaling pathways, are very complex and highly conserved tertiary kinase signaling pathways. These pathways are closely related to the osteogenic differentiation of PDLSCs, and this paper provides an overview of the research on the MAPK signaling pathways and the osteogenic differentiation of PDLSCs.

Biocompatibility of irrigation solutions to dental-derived mesenchymal stem cells in regenerative endodontic procedure: a systematic review of in vitro studies

Regenerative endodontic procedures (REPs) offer an alternative to apexification in necrotic immature permanent teeth, promoting continued root development and dentinal wall thickening. Success in REPs requires effective disinfection and the survival of dental-derived mesenchymal stem cells (DMSCs), such as dental pulp stem cells (DPSCs), stem cells from the apical papilla (SCAPs), and periodontal ligament stem cells (PDLSCs). This review investigates the biocompatibility of irrigation solutions, including sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), and chlorhexidine (CHX), on DMSCs. Following PRISMA guidelines, a comprehensive search was conducted in PubMed, Scopus, Web of Science, Cochrane, and SciELO, with the last update on March 4, 2024. Studies from January 2008 to April 2024 assessing viability, proliferation, migration, differentiation, and mineralization of DMSCs treated with NaOCl, EDTA, and CHX were included. The papers were selected using PICOS criteria and quality was assessed using the PRILE checklist and risk of bias with the Quality Assessment Tool for In Vitro Studies. Of 738 studies identified, 15 met inclusion criteria. The findings suggest that NaOCl and CHX exhibit lower biocompatibility towards DMSCs compared to EDTA. NaOCl and CHX are cytotoxic to DMSCs, while EDTA demonstrates favorable biocompatibility, promoting osteogenic differentiation and mineralization. This highlights potential implications for irrigant selection in regenerative procedures, as appropriate irrigants may enhance cellular survival and improve clinical outcomes.

Salivary periostin levels as a non-invasive biomarker and their clinical correlates among healthy and periodontitis patients-a cross-sectional analytical study

Background

The diagnosis of periodontitis is primarily through clinical and radiographic assessments. However, it is difficult for clinicians to detect incipient periodontitis during the routine clinical assessment. Identifying people at risk for periodontitis and tracking disease development need a dependable biomarker. Currently, no biomarkers meet all the criteria required for an ideal diagnostic test. Therefore, the clinical utility of salivary periostin as a potential screening tool for periodontitis warrants further investigation, particularly through large samples across diverse populations. The present study aimed to investigate salivary periostin levels as a biomarker in individuals with periodontitis and healthy controls.

Methods

Forty-five patients with generalized periodontitis stage III grade A/B and an equivalent number of periodontally healthy controls were evaluated for plaque index (PI), gingival index (GI), pocket probing depth (PPD), and clinical attachment level (CAL). Unstimulated salivary samples from all subjects were taken, and periostin levels were quantified using an ELISA kit.

Results

The average salivary periostin levels were 4.63 in the healthy group and 1.24 in the periodontitis group (P < 0.05). The Spearman coefficient indicated a negative correlation between periostin levels and the gingival index (r = -0.761), plaque index (r = -0.780; P < 0.05), probing pocket depth (PPD) (r = -0.713; P < 0.05) and clinical attachment level (CAL) (r = -0.713; P < 0.05). Linear regression analysis validated the indirect correlation between salivary periostin levels and clinical indicators (Adjusted R square = 0.947).

Conclusions

Salivary periostin levels are associated with periodontal disease. Salivary periostin levels indirectly influence as a non-invasive biomarker of periodontitis. The biomarker periostin is effective for evaluating both healthy and diseased periodontium.

Regulation and functional importance of human periodontal ligament mesenchymal stromal cells with various rates of CD146+ cells

Introduction

Mesenchymal stromal cells (MSCs) with high expression of CD146 have superior properties for tissue regeneration. However, high variability in the rate of CD146+ cells among donors is observed. In this study, the possible reasons behind this variability in human periodontal ligament MSCs (hPDL-MSCs) were explored.

Methods

hPDL-MSCs were isolated from 22 different donors, and rates of CD146+ cells were analyzed by flow cytometry. Furthermore, populations with various rates of CD146+ cells were isolated with magnetic separation. The dependency of cell proliferation, viability, cell cycle, and osteogenic differentiation on the rates of CD146+ cells was investigated. Besides, the effects of various factors, like cell density, confluence, and inflammatory environment on the CD146+ rate and expression were analyzed.

Results

The rate of CD146+ cells exhibited high variability between donors, with the percentage of CD146+ cells ranging from 3% to 67%. Higher percentage of CD146+ cells was associated with higher proliferation, presumably due to the higher percentage of cells in the S-phase, and higher osteogenic differentiation potential. Prolonged cell confluence and higher cell seeding density led to the decline in the rate of CD146+ cells. The surface rate of CD146 in hPDL-MSCs was stimulated by the treatment with interleukin-1β and tumor necrosis factor-α, and inhibited by the treatment with interferon-γ.

Conclusion

These results suggest that hPDL-MSCs with high rate of CD146+ cells are a promising subpopulation for enhancing the effectiveness of MSC-based regenerative therapies, however the rate of CD146 is affected by various factors, which must be considered for cell propagation and their potential application in vivo.

Temporal Profiling of Cellular and Molecular Processes in Osteodifferentiation of Dental Pulp Stem Cells

Based on the potential of DPSCs as the most promising candidates for bone tissue engineering, we comprehensively investigated the time-dependent cellular and molecular changes that occur during their osteodifferentiation. To analyze this area in-depth, we used both cellular and molecular approaches. Morphological changes were monitored using bright-field microscopy, while the production of mineral deposits was quantified spectrophotometrically. The expression of a key mesenchymal stem cell marker, CD90, was assessed via flow cytometry. Finally, protein-level changes in whole cells were examined by fluorescence microscopy. Our results show successful long-term osteodifferentiation of the patient's DPSCs within 25 days. In differentiated cells, mineralized extracellular matrix production gradually increased; in contrast, the expression of the specific stem cell marker CD90 significantly decreased. We observed dynamic changes in intracellular and extracellular proteins when collagen1 A1 and osteopontin appeared as earlier markers of osteogenesis, while apolipoprotein A2, bone morphogenetic protein 9, dentin sialophosphoprotein, and matrix metalloproteinase 8 were produced mainly in the late stages of this process. A decrease in actin microfilament expression indicated a reduction in cell proliferation, which could be used as another marker of osteogenic initiation. Our results suggest a coordinated process in vitro in which cells synthesize the necessary proteins and matrix components to regulate the growth of hydroxyapatite crystals and form the bone matrix.

Cystathionine γ-lyase contributes to exacerbation of periodontal destruction in experimental periodontitis under hyperglycemia

BACKGROUND

Diabetes is one of the major inflammatory comorbidities of periodontitis via 2-way interactions. Cystathionine γ-lyase (CTH) is a pivotal endogenous enzyme synthesizing hydrogen sulfide (H2S), and CTH/H2S is crucially implicated in modulating inflammation in various diseases. This study aimed to explore the potential role of CTH in experimental periodontitis under a hyperglycemic condition.

METHODS

CTH-silenced and normal human periodontal ligament cells (hPDLCs) were cultured in a high glucose and Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) condition. The effects of CTH on hPDLCs were assessed by Cell Counting Kit 8 (CCK8), real-time quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA). The model of experimental periodontitis under hyperglycemia was established on both Cth-/- and wild-type (WT) mice, and the extent of periodontal destruction was assessed by micro-CT, histology, RNA-Seq, Western blot, tartrate-resistant acid phosphatase (TRAP) staining and immunostaining.

RESULTS

CTH mRNA expression increased in hPDLCs in response to increasing concentration of P.g-LPS stimulation in a high glucose medium. With reference to WT mice, Cth-/- mice with experimental periodontitis under hyperglycemia exhibited reduced bone loss, decreased leukocyte infiltration and hindered osteoclast formation, along with reduced expression of proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in periodontal tissue. RNA-seq-enriched altered NF-κB pathway signaling in healthy murine gingiva with experimental periodontitis mice under hyperglycemia. Accordingly, phosphorylation of p65 (P-p65) was alleviated in CTH-silenced hPDLCs, leading to decreased expression of IL6 and TNF. CTH knockdown inhibited activation of nuclear factor kappa-B (NF-κB) pathway and decreased production of proinflammatory cytokines under high glucose and P.g-LPS treatment.

CONCLUSION

The present findings suggest the potential of CTH as a therapeutic target for tackling periodontitis in diabetic patients.

Parameter-Tuned Pulsed Wave Photobiomodulation Enhances Stem Cells From Apical Papilla Differentiation: Evidence From Gene and Protein Analyses

This study examines the effects of pulsed wave photobiomodulation (pwPBM) on the osteogenic differentiation of stem cells from the apical papilla (SCAP). Using 810 nm near-infrared (NIR) light with 300 Hz pulses and a 30% duty cycle, pwPBM was applied at a total energy density of 750 mJ/cm2. Osteogenesis was evaluated through both in vitro and in vivo analyses. In vitro experiments demonstrated significant enhancement of alkaline phosphatase (ALP) activity, along with upregulation of key osteogenesis-related genes and proteins, as confirmed by real-time polymerase chain reaction (PCR) and Western blot analyses. In vivo, histological assessments following SCAP transplantation revealed increased bone tissue formation, further corroborated by osteocalcin staining. These findings underscore the potential of pwPBM as an innovative and effective tool for dental tissue regeneration and engineering.

Hypoxia-inducible Factor 1α Contributes to Matrix Metalloproteinases 2/9 and Inflammatory Responses in Periodontitis

Periodontitis is a prevalent condition characterized by inflammation and tissue destruction within the periodontium, with hypoxia emerging as a contributing factor to its pathogenesis. Hypoxia-inducible factor 1α (HIF-1α) has a crucial role in orchestrating adaptive responses to hypoxic microenvironments and has been implicated in various inflammatory-related diseases. Understanding the interplay between HIF-1α, matrix metalloproteinases (MMPs), and inflammatory responses in periodontitis could provide insights into its molecular mechanisms. We investigated the relationship between HIF-1α, MMP2, and MMP9 in gingival crevicular fluid (GCF) and periodontal ligament stem cells (PDLSCs) from periodontitis patients. The expression levels of HIF-1α, MMP2, MMP9, and inflammatory factors (IL-6, IL-1β, TNF-α) were assessed using enzyme-linked immunosorbent assay (ELISA) and real-time PCR (RT-PCR). Additionally, osteogenic differentiation of PDLSCs was identified by alkaline phosphatase activity. Significantly elevated levels of HIF-1α, MMP2, and MMP9 were observed in GCF of periodontitis patients compared to controls. Positive correlations were found between HIF-1α and MMP2/MMP9, as well as with IL-6, IL-1β, and TNF-α. Modulation of HIF-1α expression in PDLSCs revealed its involvement in MMP2/9 secretion and inflammatory responses, with inhibition of HIF-1α mitigating these effects. Furthermore, HIF-1α inhibition alleviated the reduction in osteogenic differentiation induced by inflammatory stimuli. Our findings elucidate the regulatory role of HIF-1α in MMP expression, inflammatory responses, and osteogenic differentiation in periodontitis. In conclusion, targeting HIF-1α signaling pathways may offer therapeutic opportunities for managing periodontitis and promoting periodontal tissue regeneration.

WDR36 inhibits the osteogenic differentiation and migration of periodontal ligament stem cells

BACKGROUND

Periodontitis is an inflammatory disease caused by the host's immune response and various interactions between pathogens, which lead to the loss of connective tissue and bone. In recent years, mesenchymal stem cell (SC) transplantation technology has become a research hotspot, which can form periodontal ligament, cementum, and alveolar bone through proliferation and differentiation.

AIM

To elucidate the regulatory effects of WD repeat-containing protein 36 (WDR36) on the senescence, migration, and osteogenic differentiation of periodontal ligament SCs (PDLSCs).

METHODS

The migration and chemotaxis of PDLSCs were detected by the scratch-wound migration test and transwell chemotaxis test. Alkaline phosphatase (ALP) activity, Alizarin red staining, calcium content, and real-time reverse transcription polymerase chain reaction (RT-qPCR) of key transcription factors were used to detect the osteogenic differentiation function of PDLSCs. Cell senescence was determined by senescence-associated β-galactosidase staining.

RESULTS

The 24-hour and 48-hour scratch-wound migration test and 48-hour transwell chemotaxis test showed that overexpression of WDR36 inhibited the migration/chemotaxis of PDLSCs. Simultaneously, WDR36 depletion promoted the migration/chemotaxis of PDLSCs. The results of ALP activity, Alizarin red staining, calcium content, and RT-qPCR showed that overexpression of WDR36 inhibited the osteogenic differentiation of PDLSCs, and WDR36 depletion promoted the osteogenic differentiation of PDLSCs. Senescence-associated β-galactosidase staining showed that 0.1 μg/mL icariin (ICA) and overexpression of WDR36 inhibited the senescence of PDLSCs, and WDR36 depletion promoted the osteogenic differentiation of PDLSCs.

CONCLUSION

WDR36 inhibits the migration and chemotaxis, osteogenic differentiation, and senescence of PDLSCs; 0.1 μg/mL ICA inhibits the senescence of PDLSCs. Therefore, WDR36 might serve as a target for periodontal tissue regeneration and the treatment of periodontitis.

Enhanced osteogenic differentiation of human periodontal ligament cells by mature osteoclasts

OBJECTIVE

Several in vitro studies have shown that reverse signaling from osteoclasts regulates osteoblast differentiation and mineralization. However, none of these studies have reported the effects of this signaling pathway on periodontal ligament (PDL) cells. Therefore, in this study, we aimed to investigate the interaction between receptor activators of nuclear factor kappa B (RANK) released from mature human osteoclasts and the membranous RANK ligand (RANKL) in human PDL cells.

METHODS

Multinucleated mature human osteoclasts were differentiated from peripheral blood mononuclear cells upon incubation with recombinant macrophage colony-stimulating factor and RANKL. Mature osteoclasts and human PDL cells were characterized. A mature osteoclast-conditioned medium (OC-CM) was used to induce osteogenic differentiation of PDL cells. Mechanistic analysis of RANK-RANKL reverse signaling were conducted to determine the regulation of osteogenic induction using conditioned medium from mature osteoclasts treated with GW4869 (GW-OC-CM) or PDL cells pretreated with recombinant human osteoprotegerin (OPG).

RESULTS

OC-CM significantly upregulated the mRNA expression of osteogenic genes and enhanced the osteogenic differentiation and biomineralization of PDL cells (p < 0.05). GW-OC-CM significantly reduced the expression of osteogenic genes, osteogenic differentiation, and biomineralization in PDL cells (p < 0.05). Similarly, the pretreatment of PDL cells with OPG before OC-CM treatment significantly reduced the osteogenic induction of PDL cells (p < 0.05).

CONCLUSION

Mature osteoclasts can induce osteogenesis in human PDL cells via RANK-RANKL reverse signaling.

Versatile hydrogels prepared by microfluidics technology for bone tissue engineering applications

Bone defects are a prevalent issue resulting from various factors, such as trauma, degenerative diseases, congenital disabilities, and the surgical removal of tumors. Current methods for bone regeneration have limitations. In this context, the fusion of tissue engineering and microfluidics has emerged as a promising strategy in the field of bone regeneration. This study describes the classification of microfluidic devices based on the nature of flow and channel type, as well as the materials and techniques required. An overview of microfluidic methods used to prepare hydrogels and the advantages of using these hydrogels in bone tissue engineering (BTE) combining several basic elements of BTE to highlight its advantages is provided. Furthermore, this work emphasizes the benefits of using hydrogels prepared via microfluidics over conventional hydrogels in BTE because of their controlled release of cargo, they can be used for in situ injection, simplify the steps of single-cell encapsulation and have the advantages of high-throughput and precise preparation. Additionally, organ-on-a-chip models fabricated via microfluidics offer a platform for studying cell and tissue behaviors in an authentic and dynamic environment. Moreover, microfluidic devices can be utilized for noninvasive diagnosis and therapy. Finally, this paper summarizes the preclinical and clinical applications of hydrogels prepared via microfluidics for bone regeneration by focusing on their current developmental status, limitations associated with their application, and future challenges, which underscore their potential impacts on advancing regenerative medicine practices.

Biofunctionalization of Collagen Barrier Membranes with Bone-Conditioned Medium, as a Natural Source of Growth Factors, Enhances Osteoblastic Cell Behavior

A key principle of guided bone regeneration (GBR) is the use of a barrier membrane to prevent cells from non-osteogenic tissues from interfering with bone regeneration in patients with hard tissue deficiencies. The aim of the study was to investigate whether the osteoinductive properties of bone-conditioned medium (BCM) obtained from cortical bone chips harvested at the surgical site can be transferred to a native bilayer collagen membrane (nbCM). BCM extracted within 20 or 40 min, which corresponds to a typical implant surgical procedure, and BCM extracted within 24 h, which corresponds to BCM released from the autologous bone chips in situ, contained significant and comparable amounts of TGF-β1, IGF-1, FGF-2, VEGF-A, and IL-11. Significant (p < 0.001) quantities of BMP-2 were only detected in the 24-h BCM preparation. The bioactive substances contained in the BCM were adsorbed to the nbCMs with almost 100% efficiency. A fast but sequential release of all investigated proteins occurred within 6-72 h, reflecting their stepwise involvement in the natural regeneration process. BCM-coated nbCM significantly (p < 0.05) increased the migratory, adhesive, and proliferative capacity of primary human bone-derived cells (hBC), primary human periodontal ligament cells (hPDLC), and an osteosarcoma-derived osteoblastic cell line (MG-63) compared to cells cultured on BCM-free nbCM. The high proliferative rates of MG-63 cells cultured on BCM-free nbCM were not further potentiated by BCM, indicating that BCM-coated nbCM has no detrimental effects on cancer cell growth. BCM-coated nbCM caused significant (p < 0.05) induction of early osteogenic marker gene expression and alkaline phosphatase activity, suggesting an important role of BCM-functionalized nbCM in the initiation of osteogenesis. The 24-h BCM loaded on the nbCM was the only BCM preparation that caused significant induction of late osteogenic marker gene expression. Altogether, our data define the pre-activation of collagen membranes with short-term-extracted BCM as a potential superior modality for treating hard tissue deficiencies via GBR.

The chondrogenic potential of the bovine tendon sheath-a novel source of stem cells for cartilage repair

The human hand is traumatized more frequently than any other bodily part. Trauma and pathological processes (eg, rheumatoid arthritis, osteoarthritis) commonly implicate the finger joints and specifically damage also the layer of articular cartilage. Endeavors are now being made to surgically repair such cartilage lesions biologically using tissue-engineering approaches that draw on donor cells and/or donor tissues. The tendon sheaths, particularly their inner layers, that is, the peritendineum, surround the numerous tendons in the hand. The peritendineum is composed of mesenchymal tissue. We hypothesize that this tissue harbors pluripotent mesenchymal stem cells and thus could be used for cartilage repair, irrespective of the donor's age. Using a bovine model (young calves vs adult cows), the pluripotentiality of the peritendineal stem cells, namely, their osteogenicity, chondrogenicity, and adipogenicity, was investigated by implementing conventional techniques. Subsequently, the chondrogenic potential of the peritendineal tissue itself was analyzed. Its differentiation into cartilage was induced by the application of specific growth factors (members of the TGF-β-superfamily). The characteristics of the tissue formed were evaluated structurally (immuno) histochemically, histomorphometrically, and biochemically (gene expression and protein level). Our data confirm that the bovine peritendineum contains stem cells whose pluripotentiality is independent of donor age. This tissue could also be induced to differentiate into cartilage, likewise, irrespective of the donor's age. Preliminary investigations with adult human peritendineal biopsy material derived from the hand's peritendineal flexor tendon sheaths revealed that this tissue can also be induced to differentiate into cartilage.

Erroneous Differentiation of Tendon Stem/Progenitor Cells in the Pathogenesis of Tendinopathy: Current Evidence and Future Perspectives

Tendinopathy is a condition characterized by persistent tendon pain, structural damage, and compromised functionality. Presently, the treatment for tendinopathy remains a formidable challenge, partly because of its unclear pathogenesis. Tendon stem/progenitor cells (TSPCs) are essential for tendon homeostasis, regeneration, remodeling, and repair. An innovative theory has been previously proposed, with insufficient evidence, that the erroneous differentiation of TSPCs may constitute one of the fundamental mechanisms underpinning tendinopathy. Over the past few years, there has been accumulating evidence for plausibility of this theory. In this review, we delve into alterations in the differentiation potential of TSPCs and the underlying mechanisms in the context of injury-induced tendinopathy, diabetic tendinopathy, and age-related tendinopathy to provide updated evidence on the erroneous differentiation theory. Despite certain limitations inherent in the existing body of evidence, the erroneous differentiation theory emerges as a promising and highly pertinent avenue for understanding tendinopathy. In the future, advanced methodologies will be harnessed to further deepen comprehension of this theory, paving the way for prospective developments in clinical therapies targeting TSPCs for the management of tendinopathy.

Wnt/β-catenin Promotes Cementum Apposition in Periodontal Regeneration

Regeneration of periodontal tissue, particularly the cementum-periodontal ligament (PDL)-bone complex, has long been challenging because the differentiation kinetics of cells and the molecular pathways contributing to the regeneration process are largely unknown. We aimed to evaluate the cell behavior and molecular pathways that contribute to periodontal tissue regeneration in vivo. We analyzed the process of periodontal tissue regeneration through subrenal capsule transplantation of immediately extracted molars in mice. We showed that the regenerated periodontal tissue in the subrenal capsule was morphologically comparable to the intact periodontal tissue, with increased cellular cementum thickness in the apical region. Cell tracing analysis revealed that the cells comprising the regenerated periodontal tissue were derived from transplanted teeth and were indispensable for periodontal tissue regeneration, whereas recipient mouse-derived cells partly contributed to angiogenesis. Bioinformatics analysis based on the gene expression profile in the transplanted teeth indicated that Wnt/β-catenin signaling is involved in periodontal tissue regeneration, which was further confirmed through β-catenin immunohistochemistry. Moreover, the constitutive activation of β-catenin in the cells of transplanted teeth was found to promote accelerated cellular cementum apposition, while the conditional knockout of β-catenin in the cells of transplanted teeth suppressed cellular cementum apposition. Notably, the manipulation of Wnt/β-catenin signaling did not interfere with the bone-PDL-cementum complex, while endogenous osteoclast activity was affected in bone. Our results demonstrated the essential roles of endogenous PDL cells in periodontal tissue regeneration and that Wnt/β-catenin signaling is involved in this process, particularly cellular cementum apposition. Hence, controlling this pathway could promote cementum regeneration, which is a critical process for the regeneration of the cementum-PDL-bone complex. This study provides novel insights into cell behavior and signaling pathways that will advance practical periodontal tissue regeneration.

Efficacy of Simvastatin in Inhibiting Bone Resorption and Promoting Healing in Delayed Tooth Avulsion: A Case Series

An avulsion is a severe dental injury characterized by the complete displacement of a tooth from its socket, often resulting in a compromised prognosis. One of the key factors influencing the success of reimplantation is the extraoral dry time, which refers to the duration the tooth remains outside of the socket. Prolonged dry time significantly impairs the viability of the periodontal ligament cells, crucial for successful healing and reattachment. Despite various protocols and treatment strategies developed to manage avulsed teeth, no single approach addresses all treatment needs effectively, particularly in cases of delayed reimplantation. Simvastatin, an anti-lipidemic drug, has demonstrated pleiotropic effects that extend beyond cholesterol lowering. These effects include anti-inflammatory properties, promotion of bone regeneration, and enhancement of periodontal ligament cell survival. Such actions suggest that simvastatin may have a beneficial role in improving outcomes following the delayed reimplantation of avulsed teeth. This case series proposes the use of simvastatin as an adjunctive treatment for avulsed teeth along with platelet-rich fibrin and hydroxyapatite, particularly in situations where reimplantation is delayed. By mitigating inflammation and stimulating tissue regeneration, simvastatin may help counteract the damage caused by prolonged extraoral dry time. Its potential to promote periodontal ligament cell survival and enhance healing processes could improve the prognosis of reimplantation, even in cases where traditional treatment alone would be less effective. Given these promising properties, simvastatin may represent a valuable addition to the treatment protocol for avulsed teeth with extended dry times. However, further clinical studies and trials are necessary to validate its efficacy and establish a clear role in the management of delayed reimplantation.

Chairside live biotherapeutic hydrogel for comprehensive periodontitis therapy

Periodontitis, characterized by microbial dysbiosis and immune dysregulation, destroys tooth-supporting tissues and negatively affects overall health. Current strategies face significant challenges in restoring damaged tissues while halting periodontitis progression. In this study, we introduce a live biotherapeutic product (LBP) in an engineered living hydrogel for comprehensive periodontitis therapy. A dental blue light-responsive hydrogel (LRG) was fabricated to deliver and confine live Lactobacillus rhamnosus GG (LGG) in periodontal pockets, endowing the LRG with sustained antibacterial and immunomodulatory effects. The LRG was engineered through peptide modification to also promote tissue regeneration. Both in vitro and in vivo evaluations confirmed the effectiveness of this integrated therapeutic strategy, which combines antibacterial, anti-inflammatory, and regenerative properties with an underlying immunomodulatory mechanism that involves suppressor of cytokine signaling (SOCS)3 upregulation and the Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway suppression in macrophages. Demonstrating a new paradigm, this proof of concept highlights the synergistic integration of live organisms and synthetic material engineering in a chairside treatment to address the multifaceted etiology of periodontitis.

Controlled TPCA-1 delivery engineers a pro-tenogenic niche to initiate tendon regeneration by targeting IKKβ/NF-κB signaling

Tendon repair remains challenging due to its poor intrinsic healing capacity, and stem cell therapy has emerged as a promising strategy to promote tendon regeneration. Nevertheless, the inflammatory environment following acute tendon injuries disrupts stem cell differentiation, leading to unsatisfied outcomes. Our study recognized the critical role of NF-κB signaling in activating inflammation and suppressing tenogenic differentiation of stem cells after acute tendon injury via multiomics analysis. TPCA-1, a selective inhibitor of IKKβ/NF-κB signaling, efficiently restored the impaired tenogenesis of stem cells in the inflammatory environment. By developing a microsphere-incorporated hydrogel system for stem cell delivery and controlled release of TPCA-1, we successfully engineered a pro-tenogenic niche to initiate tenogenesis for tendon regeneration. Collectively, we recognize NF-κB signaling as a critical target to tailor a pro-tenogenic niche and propose the combined delivery of stem cells and TPCA-1 as a potential strategy for acute tendon injuries.

Biofabrication - Revolutionizing the future of regenerative periodontics

Periodontium is a compartmentalized and highly specialized tissue responsible for tooth stability. Loss of tooth attachment due to periodontitis and trauma is a complex clinical burden affecting a large parcel of the adult and elderly population worldwide, and regenerative strategies to reestablish the native conditions of the periodontium are paramount. Biofabrication of scaffolds, through various techniques and materials, for regenerative periodontics has significantly evolved in the last decades. From the basics of occlusive membranes and graft materials to the complexity of converging 3D printing and Bioprinting using image-based models, biofabrication opens many possibilities for patient-specific scaffolds that recapitulate the anatomical and physiological conditions of periodontal tissues and interfaces. Thus, this review presents fundamental concepts related to the native characteristics of the periodontal tissues, the key to designing personalized strategies, and the latest trends of biofabrication in regenerative periodontics with a critical overview of how these emerging technologies have the potential to shift the one-size-fits-all paradigm.

MicroRNA functions in osteogenic differentiation of periodontal ligament stem cells: a scoping review

This scoping review aimed to describe the differential microRNA (miRNA) functions in osteogenic differentiation of periodontal ligament stem cells (PDLSCs), and then analyze the potential of applying PDLSCs and miRNAs in bone regeneration. The databases of PubMed, Google Scholar and EBSCO search were performed by the 4 themes, including periodontal ligament stem cells, miRNA, osteogenic differentiation, and tissue regeneration. The original articles described miRNA functions in osteogenic differentiation of PDLSCs were identified and selected for content analyze. The articles suggested that PDLSCs have high potential in bone regeneration because of their multipotency and immunomodulation. PDLSCs are conveniently accessible and obtained from extracted teeth. However, recent evidence reported that PDLSCs of various origins demonstrate differential characteristics of osteogenic differentiation. Exosomal miRNAs of PDLSCs demonstrate a regulatory role in tissue regeneration. The properties of PDLSCs associated to miRNA functions are altered in differential microenvironmental conditions such as infection, inflammation, high-glucose environment, or mechanical force. Therefore, these factors must be considered when inflamed PDLSCs are used for tissue regeneration. The results suggested inflammation-free PDLSCs harvested from the middle third of root surface provide the best osteogenic potential. Alternatively, the addition of miRNA as a bioactive molecule also increases the success of PDLSCs therapy to enhance their osteogenic differentiation. In conclusion, Exosome-derived miRNAs play a key role in PDLSCs osteogenic differentiation during tissue regeneration. While the success of PDLSCs in tissue regeneration could be uncertain by many factors, the use of miRNAs as an adjunct is beneficial for new bone regeneration.

Proteome differences of dental stem cells between permanent and deciduous teeth by data-independent acquisition proteomics

Dental pulp stem cells hold significant prospects for tooth regeneration and repair. However, a comprehensive understanding of the molecular differences between dental pulp stem cells (DPSC, from permanent teeth) and stem cells from human exfoliated deciduous teeth (SHED, from deciduous teeth) remains elusive, which is crucial for optimizing their therapeutic potential. To address this gap, we employed a novel data-independent acquisition (DIA) proteomics approach to compare the protein expression profiles of DPSC and SHED. Based on nano-LC-MS/MS DIA proteomics, we identified over 7,000 proteins in both cell types. By comparing their expression levels, 209 differentially expressed proteins were identified. Subsequent Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses, along with protein-protein interaction network construction, revealed significant metabolic differences and key regulatory nodes. DPSC exhibited significantly higher expression of proteins belonging to the NDUFB family, SMARC family, RPTOR and TLR3. These proteins are known to be involved in critical cellular processes such as mitochondrial energy metabolism, mTOR-related autophagy pathway, and innate immune response. Conversely, SHED displayed elevated expression of AKR1B family, which participated in glycerolipid metabolism and adipogenic differentiation, PRKG1, MGLL and UQCRB proteins associated with thermogenesis. These findings highlight the specific proteomic landscape of DPSC and SHED, suggesting their distinct biological roles and potential applications.

Cell Homing Strategies in Regenerative Endodontic Therapy

Cell homing, a process that leverages the body's natural ability to recruit cells and repair damaged tissues, presents a promising alternative to cell transplantation methods. Central to this approach is the recruitment of endogenous stem/progenitor cells-such as those from the apical papilla, bone marrow, and periapical tissues-facilitated by chemotactic biological cues. Moreover, biomaterial scaffolds embedded with signaling molecules create supportive environments, promoting cell migration, adhesion, and differentiation for the regeneration of the pulp-dentin complex. By analyzing in vivo animal studies using cell homing strategies, this review explores how biomolecules and scaffold materials enhance the recruitment of endogenous stem cells to the site of damaged dental pulp tissue, thereby promoting repair and regeneration. It also examines the key principles, recent advancements, and current limitations linked to cell homing-based regenerative endodontic therapy, highlighting the interplay of biomaterials, signaling molecules, and their broader clinical implications.

The effect of low energy LED red light on osteogenetic differentiation of periodontal ligament stem cell via the ERK5 signal pathway

PURPOSE

The purpose of this study was to examine how low-energy LED red light influences the early to middle stage of osteogenic differentiation of periodontal ligament stem cells (PDLSCs) via the ERK5 signaling pathway.  METHODS: PDLSCs were extracted from periodontal membrane tissue using enzymatic digestion. At three time points of 7, 10, and 14 days after irradiation with 5J/cm2 LED red light, the expression levels of early to middle-stage osteogenic-related genes ALP, Col-1, BSP, and OPN were detected by real-time fluorescence quantitative PCR(qRT-PCR) in both control and osteogenesis experimental groups. The addition of BIX02189 could block the ERK5 signaling pathway. Under irradiation with 5J/cm2 LED red light, the expression levels of the ERK5 gene, related proteins ERK5, p-ERK5, as well as early to middle-stage osteogenic-related genes ALP, Col-1, BSP, and OPN were detected by qRT-PCR and Western blot in the osteogenic medium group and the osteogenic medium + BIX02189 group.  RESULTS: Both low-energy LED red light and osteogenic medium could induce osteogenesis and differentiation of PDLSCs, upregulating the expression of ALP, Col-1, BSP, and OPN genes in PDLSCs. Their combination also produced a synergistic effect. Moreover, the ERK5 signaling pathway participated in the promoting effect of LED red light on the early to middle-stage osteogenic differentiation of PDLSCs, indicating a positive role of LED red light in this process.  CONCLUSIONS: The ERK5 signaling pathway can mediate the promotion of early to middle-stage osteogenic differentiation of PDLSCs by low-energy LED red light.

PIK3R3 regulates differentiation and senescence of periodontal ligament stem cells and mitigates age-related alveolar bone loss by modulating FOXO1 expression

INTRODUCTION

Periodontal diseases are prevalent among middle-aged and elderly individuals. There's still no satisfactory solution for tooth loss caused by periodontal diseases. Human periodontal ligament stem cells (hPDLSCs) is a distinctive subgroup of mesenchymal stem cells, which play a crucial role in periodontal supportive tissues, but their application value hasn't been fully explored yet. As a regulatory subunit of PI3K, PIK3R3's role in stem cell regulation remains poorly comprehended.

OBJECTIVES

This study aims to explore the regulatory effect of PIK3R3 on differentiation and senescence of hPDLSCs and the underlying mechanism, as well as whether overexpression of PIK3R3 mitigate alveolar bone loss in aged rats.

METHODS

Human PDLSC lines with both PIK3R3 knockdown and overexpression are established. Osteogenic, adipogenic, chondrogenic and senescent induction are used to test the effect of PIK3R3 on senescence in vitro. Model of alveolar bone loss in aged mice is used to reveal the effect of PIK3R3 in vivo. FOXO1 siRNA is used for mechanism exploration.

RESULTS

Knockdown of PIK3R3 inhibits the mRNA and protein expression of markers in osteogenic, adipogenic, and chondrogenic differentiation of hPDLSCs but promotes in vitro senescence of hPDLSCs, including senescence markers expression, telomerase density and reactive oxygen species. Overexpression of PIK3R3 has the opposite effect. Furthermore, the result of Micro-CT and tissue section shows that overexpression of PIK3R3 in elder rats mitigates alveolar bone loss. Mechanistically, PIK3R3 regulates senescence of hPDLSCs through modulating FOXO1 expression. Expression of FOXO1 is altered when PIK3R3 is knocked down or overexpressed in senescent medium. Knockdown of FOXO1 promotes senescence of hPDLSCs and the senescence promoting effect of knocking down PIK3R3 is weakened when FOXO1 is highly expressed.

CONCLUSION

These findings indicate that PIK3R3 modulates senescence of hPDLSCs by regulating FOXO1 expression and shows promise as a therapeutic target for mitigating age-related alveolar bone loss.

Mesenchymal stem cell-mediated adipogenic transformation: a key driver of oral squamous cell carcinoma progression

BACKGROUND

Interaction between mesenchymal stem cells (MSCs) and oral squamous cell carcinoma (OSCC) cells plays a major role in OSCC progression. However, little is known about adipogenic differentiation alteration in OSCC-derived MSCs (OSCC-MSCs) and how these alterations affect OSCC growth.

METHODS

MSCs were successfully isolated and cultured from normal gingival tissue, OSCC peritumoral tissue, and OSCC tissue. This included gingiva-derived MSCs (GMSCs), OSCC adjacent noncancerous tissues-derived MSCs (OSCCN-MSCs), and OSCC-MSCs. The adipogenic and osteogenic differentiation capabilities of these cells were evaluated using Oil Red O and Alizarin Red S staining, respectively. OSCC cells were then co-cultured with either OSCC-MSCs or GMSCs to assess the impact on OSCC cell proliferation and migration. Subcutaneous xenograft experiments were conducted in BALB/c-nu mice to further investigate the effects in vivo. Additionally, immunohistochemical staining was performed on clinical samples to determine the expression levels of fatty acid synthase (FASN) and the proliferation marker Ki67.

RESULTS

OSCC-MSCs exhibited enhanced adipogenic differentiation and reduced osteogenic differentiation compared to GMSCs. OSCC-MSCs significantly increased the proliferation and migration of OSCC cells relative to GMSCs and promoted tumor growth in mouse xenografts. Lipid droplet accumulation in the stroma was significantly more pronounced in OSCC + OSCC-MSCs xenografts compared to OSCC + GMSCs xenografts. Free fatty acids (FFAs) levels were elevated in OSCC tissues compared to normal gingival tissues. Moreover, OSCC-MSCs consistently secreted higher levels of FFAs in condition medium than GMSCs. Knockdown of FASN in OSCC-MSCs reduced their adipogenic potential and inhibited their ability to promote OSCC cell proliferation and migration. Clinical sample analysis confirmed higher FASN expression in OSCC stroma, correlating with larger tumor size and increased Ki67 expression in cancer tissues, and was associated with poorer overall survival.

CONCLUSIONS

OSCC-MSCs promoted OSCC proliferation and migration by upregulating FASN expression and facilitating FFAs secretion. Our results provide new insight into the mechanism of OSCC progression and suggest that the FASN of OSCC-MSCs may be potential targets of OSCC in the future.

Periodontal response to nonsurgical accelerated orthodontic tooth movement

Tooth movement is a complex process involving the vascularization of the tissues, remodeling of the bone cells, and periodontal ligament fibroblasts under the hormonal and neuronal regulation mechanisms in response to mechanical force application. Therefore, it will inevitably impact periodontal tissues. Prolonged treatment can lead to adverse effects on teeth and periodontal tissues, prompting the development of various methods to reduce the length of orthodontic treatment. These methods are surgical or nonsurgical interventions applied simultaneously within the orthodontic treatment. The main target of nonsurgical approaches is modulating the response of the periodontal tissues to the orthodontic force. They stimulate osteoclasts and osteoclastic bone resorption in a controlled manner to facilitate tooth movement. Among various nonsurgical methods, the most promising clinical results have been achieved with photobiomodulation (PBM) therapy. Clinical data on electric/magnetic stimulation, pharmacologic administrations, and vibration forces indicate the need for further studies to improve their efficiency. This growing field will lead to a paradigm shift as we understand the biological response to these approaches and their adoption in clinical practice. This review will specifically focus on the impact of nonsurgical methods on periodontal tissues, providing a comprehensive understanding of this significant and understudied aspect of orthodontic care.

Potential of Trilayered Gelatin/Polycaprolactone Nanofibers for Periodontal Regeneration: An In Vitro Study

Over the past few years, biomaterial-based periodontal tissue engineering has gained popularity. An ideal biomaterial for treating periodontal defects is expected to stimulate periodontal-derived cells, allowing them to contribute most efficiently to tissue reconstruction. The present study focuses on evaluating the in vitro behavior of human periodontal ligament-derived stromal cells (hPDL-MSCs) when cultured on gelatin/Polycaprolactone prototype (GPP) and volume-stable collagen matrix (VSCM). Cells were cultured onto the GPP, VSCM, or tissue culture plate (TCP) for 3, 7, and 14 days. Cell morphology, adhesion, proliferation/viability, the gene expression of Collagen type I, alpha1 (COL1A1), Vascular endothelial growth factor A (VEGF-A), Periostin (POSTN), Cementum protein 1 (CEMP1), Cementum attachment protein (CAP), Interleukin 8 (IL-8) and Osteocalcin (OCN), and the levels of VEGF-A and IL-8 proteins were investigated. hPDL-MSCs attached to both biomaterials exhibited a different morphology compared to TCP. GPP exhibited stronger capabilities in enhancing cell viability and metabolic activity compared to VSCM. In most cases, the expression of all investigated genes, except POSTN, was stimulated by both materials, with GPP having a superior effect on COL1A1 and VEGF-A, and VSCM on OCN. The IL-8 protein production was slightly higher in cells grown on VSCM. GPP also exhibited the ability to absorb VEGF-A protein. The gene expression of POSTN was promoted by GPP and slightly suppressed by VSCM. In summary, our findings indicate that GPP electrospun nanofibers effectively promote the functional performance of PDLSCs in periodontal regeneration, particularly in the periodontal ligament and cementum compartment.

A Multifunctional miRNA Delivery System Based on Tetrahedral Framework Nucleic Acids for Regulating Inflammatory Periodontal Ligament Stem Cells and Attenuating Periodontitis Bone Loss

Periodontitis is a chronic inflammatory disease that leads to periodontal tissue damage and tooth loss. Therefore, controlling inflammatory bone loss and promoting osteogenesis is a crucial challenge clinically. MicroRNA (miRNA) based gene therapy has shown substantial prospects in recent years, but its application has been limited due to structural instability and easy degradation by enzymes. Research has shown that miRNA-200c is regarded as a key miRNA by regulating multiple signaling pathways during the process of bone resorption. Tetrahedral framework nucleic acid (tFNA) can be considered an ideal carrier of miRNA due to its good tissue permeability, cell uptake efficiency, and biocompatibility. This study developed a tFNA system carrying miR-200c, named T-200c, to exert various biological effects in human periodontal ligament stem cells (PDLSCs). The activation of the NF-κB pathway is diminished, whereas the Akt/β-catenin pathway is enhanced, resulting in a notable decrease in the release of diverse inflammatory mediators and cellular reactive oxygen species. This modulation fosters cell proliferation and osteogenic differentiation, thereby rejuvenating the functionality of PDLSCs. These changes offer a viable alternative for the treatment of periodontitis and the regeneration of periodontal tissues.