Rutin protects human periodontal ligament stem cells from TNF-α induced damage to osteogenic differentiation through suppressing mTOR signaling pathway in inflammatory environment

Loading rutin on surfaces by the layer-by-layer assembly technique to improve the oxidation resistance and osteogenesis of titanium implants in osteoporotic rats

The purpose of this study was to construct a rutin-controlled release system on the surface of Ti substrates and investigate its effects on osteogenesis and osseointegration on the surface of implants. The base layer, polyethylenimine (PEI), was immobilised on a titanium substrate. Then, hyaluronic acid (HA)/chitosan (CS)-rutin (RT) multilayer films were assembled on the PEI using layer-by-layer (LBL) assembly technology. We used scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and contact angle measurements to examine all Ti samples. The drug release test of rutin was also carried out to detect the slow-release performance. The osteogenic abilities of the samples were evaluated by experiments on an osteoporosis rat model and MC3T3-E1 cells. The results (SEM, FTIR and contact angle measurements) all confirmed that the PEI substrate layer and HA/CS-RT multilayer film were effectively immobilised on titanium. The drug release test revealed that a rutin controlled release mechanism had been successfully established. Furthermore, thein vitrodata revealed that osteoblasts on the coated titanium matrix had greater adhesion, proliferation, and differentiation capacity than the osteoblasts on the pure titanium surface. When MC3T3-E1 cells were exposed to H2O2-induced oxidative stressin vitro, cell-based tests revealed great tolerance and increased osteogenic potential on HA/CS-RT substrates. We also found that the HA/CS-RT coating significantly increased the new bone mass around the implant. The LBL-deposited HA/CS-RT multilayer coating on the titanium base surface established an excellent rutin-controlled release system, which significantly improved osseointegration and promoted osteogenesis under oxidative stress conditions, suggesting a new implant therapy strategy for patients with osteoporosis.

Diosgenin prevents periodontitis by inhibiting inflammation and promoting osteogenic differentiation

Diosgenin, an essential dietary steroidal sapogenin, possess multiple pharmacological activities. This study aimed to assess the effects of diosgenin on periodontitis and elucidate the mechanisms. Lipopolysaccharide (LPS)-stimulated human periodontal ligament stem cells (hPDLCs) and a Porphyromonas gingivalis (P.g) plus ligation-induced animal model were used for in vitro and in vivo studies, respectively. Inflammatory responses, nuclear factor κ-B (NF-κB) signaling and osteogenesis-related markers were measured both in LPS-stimulated hPDLSCs and in gingival tissue of periodontitis rats. Treatment with diosgenin significantly inhibited the production of tumor necrosis factor α (TNF-α), interleukin (IL)-1β, and interleukin (IL)-6 and the activation of NF-κB pathway in LPS-stimulated hPDLSCs. Further, treatment with diosgenin enhanced the expression of osteoblast-related genes and increased the osteogenic differentiation capacity. Further, activation NF-κB pathway largely abolished the protective effects of diosgenin. Consistent with the in vitro studies, in vivo studies showed that administering diosgenin to periodontitis rats significantly lowered the levels of the TNF-α, IL-1β, and IL-6 and the inflammatory transcription factor NF-κB in gingival tissue. In addition, osteoblast-related genes were promoted. Diosgenin attenuates periodontitis by adjusting NF-κB signaling to inhibit inflammatory effects and promoting osteogenesis, suggesting diosgenin might be developed as a therapeutic strategy for treating periodontitis in the future.

RUTIN, a widely consumed flavonoid, that commonly induces hormetic effects

Rutin is a flavonoid present in numerous fruits and vegetables and therefore widely consumed by humans. It is also a popular dietary supplement of 250-500 mg/day. There is considerable consumer interest in rutin due to numerous reports in the biomedical literature of its multi-system chemo-preventive properties. The present paper provides the first assessment of rutin-induced hormetic concentration/dose responses, their quantitative features and mechanistic basis, along with their biological, biomedical, clinical, and public health implications. The findings indicate that rutin-induced hormetic dose responses are widespread, being reported in numerous biological models and cell types for a wide range of endpoints. Of critical importance is that the optimal hormetic findings shown in in vitro systems are currently not achievable for human populations due to low gastrointestinal tract bioavailability. These findings have the potential to strengthen future experimental studies with rutin, particularly concerning study design parameters.

Macrophage-derived exosomes rescue the TNF-ɑ-suppressed osteo-/cementogenic differentiation of hPDLCs

OBJECTIVE

Inflammatory stimuli compromise the differentiation potency of human periodontal ligament cells (hPDLCs). Macrophage-derived exosomes (M-Exo) play a role in several aspects of cellular activity. This study investigated how M-Exo contributes to the osteo-/cementogenic differentiation of hPDLCs under inflammation and the mechanism involved.

METHODS

M-Exo was identified by transmission electron microscopy, western blotting (WB), and dynamic light scattering. The internalization of M-Exo by hPDLCs was observed. After M-Exo treatment, the osteo-/cementogenic markers were detected by RT-qPCR and WB, and alkaline phosphatase (ALP) activity by ALP staining. Tumor necrosis factor alpha (TNF-ɑ) was applied to simulate inflammation. The rescue effect of M-Exo on TNF-ɑ-suppressed differentiation was validated. The p38 MAPK pathway activity was tested and a specific inhibitor was applied to explore the mechanism.

RESULTS

M-Exo was successfully isolated, identified and internalized by hPDLCs. M-Exo enhanced the osteo-/cementogenic differentiation of hPDLCs, as indicated by upregulated osteo-/cementogenic markers and elevated ALP activity. Moreover, TNF-ɑ inhibited the differentiation capabilities of hPDLCs, on which M-Exo showed a rescue effect. M-Exo activated the p38 MAPK pathway and SB203580 attenuated its promotion effect.

CONCLUSION

This study showed that M-Exo ameliorated the TNF-ɑ-suppressed osteo-/cementogenic differentiation of hPDLCs partly through the p38 MAPK pathway.

Synthetic Calcium-Phosphate Materials for Bone Grafting

Synthetic bone grafting materials play a significant role in various medical applications involving bone regeneration and repair. Their ability to mimic the properties of natural bone and promote the healing process has contributed to their growing relevance. While calcium-phosphates and their composites with various polymers and biopolymers are widely used in clinical and experimental research, the diverse range of available polymer-based materials poses challenges in selecting the most suitable grafts for successful bone repair. This review aims to address the fundamental issues of bone biology and regeneration while providing a clear perspective on the principles guiding the development of synthetic materials. In this study, we delve into the basic principles underlying the creation of synthetic bone composites and explore the mechanisms of formation for biologically important complexes and structures associated with the various constituent parts of these materials. Additionally, we offer comprehensive information on the application of biologically active substances to enhance the properties and bioactivity of synthetic bone grafting materials. By presenting these insights, our review enables a deeper understanding of the regeneration processes facilitated by the application of synthetic bone composites.

Signalling pathways in the osteogenic differentiation of periodontal ligament stem cells

Periodontal ligament stem cells (PDLSCs) have multidirectional differentiation potential and self-renewal abilities and are important seed cells for the regenerative repair of periodontal tissues. In recent years, many studies have identified multiple signalling pathways involved in regulating the osteogenic differentiation of PDLSCs in an inflammatory environment. In this article, we review the osteogenic differentiation of PDLSCs in an inflammatory environment in terms of signalling pathways and provide new ideas for the regenerative treatment of periodontal tissues.

Immunomodulatory effects and mechanisms of the extracts and secondary compounds of Zingiber and Alpinia species: a review

Zingiber and Alpinia species (family: Zingiberaceae) are popularly used in food as spices and flavoring agents and in ethnomedicine to heal numerous diseases, including immune-related disorders. However, their ethnomedicinal uses have not been sufficiently supported by scientific investigations. Numerous studies on the modulating effects of plants and their bioactive compounds on the different steps of the immune system have been documented. This review aimed to highlight up-to-date research findings and critically analyze the modulatory effects and mechanisms of the extracts and secondary compounds of several Zingiber and Alpinia species, namely, Zingiber officinale Roscoe, Z. cassumunar Roxb., Z. zerumbet (L.) Roscoe ex Sm., Alpinia galanga Linn., A. conchigera Griff, A. katsumadai Hayata, A. oxyphylla Miq., A. officinarum Hance, A. zerumbet (Pers.) Burtt. et Smith, and A. purpurata (Viell.) K. Schum. on the immune system, particularly via the inflammation-related signaling pathways. The immunomodulating activities of the crude extracts of the plants have been reported, but the constituents contributing to the activities have mostly not been identified. Among the extracts, Z. officinale extracts were the most investigated for their in vitro, in vivo, and clinical effects on the immune system. Among the bioactive metabolites, 6-, 8-, and 10-gingerols, 6-shogaol, and zerumbone from Zingiber species and cardamomin, 1'-acetoxychavicol acetate, yakuchinone, rutin, 1,8-cineole, and lectin from Alpinia species have demonstrated strong immunomodulating effects. More experimental studies using cell and animal models of immune-related disorders are necessary to further understand the underlying mechanisms, together with elaborate preclinical pharmacokinetics, pharmacodynamics, bioavailability, and toxicity studies. Many of these extracts and secondary metabolites are potential candidates for clinical development in immunomodulating agents or functional foods to prevent and treat chronic inflammatory disorders.

Role of histone deacetylase 9 in human periodontal ligament stem cells autophagy in a tumour necrosis factor α-induced inflammatory environment

Histone deacetylases (HDACs) play important roles in the post-translational modification of histones, which can affect the biological properties of cells, thereby altering disease progression and outcomes. However, it remains unclear how HDAC9, a class II HDAC, affects the autophagy of human periodontal ligament stem cells (hPDLSCs). We aimed to identify its role in autophagy in hPDLSCs in an inflammatory environment and to explore the potential regulatory mechanisms. A rat periodontitis model was induced by ligating the molars with silk thread. Expression of autophagy-related genes and TNF-α was elevated in this model. TNF-α was used to stimulate hPDLSCs to establish an inflammatory environment. In the TNF-α-stimulated hPDLSCs, the expression of ATG7, ATG12, Beclin-1, LC3 and HDAC9 was upregulated, and that of p62 was downregulated. When HDAC9 expression was inhibited, autophagy-related genes expression was downregulated, and p62 expression was upregulated in TNF-α-treated hPDLSCs, indicating that autophagy was inhibited under these conditions. ERK pathway inhibition significantly reduced HDAC9-mediated autophagy in TNF-α-treated hPDLSCs. These findings reveal that autophagy occurred in our rat periodontitis model and that HDAC9 regulated autophagy via ERK pathways in hPDLSCs in the inflammatory environment. HDAC9 is therefore a potential target for the treatment of periodontitis.

MiR-217 regulates autophagy through OPG/RANKL/RANK in giant cell tumors

BACKGROUND

Increasing evidence suggests that microRNAs (miRNAs) play a crucial role in cancer development and progression. Our previous study showed remarkably lower levels of miR-217 in GCT cells and tissues, and miR-217 re-expression inhibited the occurrence and development of GCT in vitro; however, the associated mechanisms remain unknown. Thus, this study aimed to explore the mechanisms underlying the proliferation inhibitory effect of miR-217 in GCT cells.

METHODS

The proliferative potential of the GCT cells was measured with an MTT assay and BrdU straining. Changes in GCT cell migration and invasion was assessed by a transwell assay. Finally, Western blot and RT-PCR assays were employed to evaluate OPG/RANKL/RANK signaling pathway-related protein expression.

RESULTS

The excessive upregulation of miR-217 markedly suppressed GCT cell proliferation and tumorigenesis both in vitro and in vivo. miR-217 overexpression could inhibit the OPG/RANKL/RANK signaling pathway in vitro and in vivo. Furthermore, ALP activity was significantly decreased in GCT cells following miR-217 treatment. Importantly, miR-217 could inhibit autophagy-related protein expression and autophagosome/autolysosome formation in GCT cells and tissues.

CONCLUSION

These results suggest that miR-217 upregulation could inhibit the occurrence and development of GCT by blocking autophagy. These findings offer an effective therapeutic target to improve the survival rates of patients with CGT in the future.

Regulation of the Host Immune Microenvironment in Periodontitis and Periodontal Bone Remodeling

The periodontal immune microenvironment is a delicate regulatory system that involves a variety of host immune cells including neutrophils, macrophages, T cells, dendritic cells and mesenchymal stem cells. The dysfunction or overactivation of any kind of local cells, and eventually the imbalance of the entire molecular regulatory network, leads to periodontal inflammation and tissue destruction. In this review, the basic characteristics of various host cells in the periodontal immune microenvironment and the regulatory network mechanism of host cells involved in the pathogenesis of periodontitis and periodontal bone remodeling are summarized, with emphasis on the immune regulatory network that regulates the periodontal microenvironment and maintains a dynamic balance. Future strategies for the clinical treatment of periodontitis and periodontal tissue regeneration need to develop new targeted synergistic drugs and/or novel technologies to clarify the regulatory mechanism of the local microenvironment. This review aims to provide clues and a theoretical basis for future research in this field.

TNF-α Inhibitors from Natural Compounds: An Overview, CADD Approaches, and their Exploration for Anti-inflammatory Agents

Inflammation is a natural process that occurs in the organism in response to harmful external agents. Despite being considered beneficial, exaggerated cases can cause severe problems for the body. The main inflammatory manifestations are pain, increased temperature, edema, decreased mobility, and quality of life for affected individuals. Diseases such as arthritis, cancer, allergies, infections, arteriosclerosis, neurodegenerative diseases, and metabolic problems are mainly characterized by an exaggerated inflammatory response. Inflammation is related to two categories of substances: pro- and anti-inflammatory mediators. Among the pro-inflammatory mediators is Tumor Necrosis Factor-α (TNF-α). It is associated with immune diseases, cancer, and psychiatric disorders which increase its excretion. Thus, it becomes a target widely used in discovering new antiinflammatory drugs. In this context, secondary metabolites biosynthesized by plants have been used for thousands of years and continue to be one of the primary sources of new drug scaffolds against inflammatory diseases. To decrease costs related to the drug discovery process, Computer-Aided Drug Design (CADD) techniques are broadly explored to increase the chances of success. In this review, the main natural compounds derived from alkaloids, flavonoids, terpene, and polyphenols as promising TNF-α inhibitors will be discussed. Finally, we applied a molecular modeling protocol involving all compounds described here, suggesting that their interactions with Tyr⁵⁹, Tyr¹¹⁹, Tyr¹⁵¹, Leu⁵⁷, and Gly¹²¹ residues are essential for the activity. Such findings can be useful for research groups worldwide to design new anti-inflammatory TNF-α inhibitors.

Erythropoietin Activates Autophagy to Regulate Apoptosis and Angiogenesis of Periodontal Ligament Stem Cells via the Akt/ERK1/2/BAD Signaling Pathway under Inflammatory Microenvironment

Background. Angiogenic tissue engineering is a vital problem waiting to be settled for periodontal regeneration. Erythropoietin, a multieffect cytokine, has been reported as a protective factor for cell fate. According to our previous study, erythropoietin has a significantly angiogenic effect on periodontal ligament stem cells. To further explore its potential effects and mechanism, we studied biological behaviors of periodontal ligament stem cells under inflammatory microenvironment induced by different concentrations (0, 10, 20, 50, and 100 ng/mL) of tumor necrosis factor-α (TNF-α) and examined how different concentrations (0, 5, 10, 20, and 50 IU/mL) of erythropoietin changed biological behaviors of periodontal ligament stem cells. Materials and Methods. Cell Counting Kit-8 was used for cell proliferation assay. Annexin V-PI-FITC was used for cell apoptosis through flow cytometry. Matrigel plug was adopted to measure the angiogenic capacity in vitro. RNA sequencing was used to detect the downstream signaling pathway. Quantitative real-time polymerase chain reaction was conducted to examine mRNA expression level. Western blot and immunofluorescence were applied to testify the protein expression level. Results. Periodontal ligament stem cells upregulated apoptosis and suppressed autophagy and angiogenesis under inflammatory microenvironment. Erythropoietin could activate autophagy to rescue apoptosis and angiogenesis levels of periodontal ligament stem cells through the Akt/Erk1/2/BAD signaling pathway under inflammatory microenvironment. Conclusions. Erythropoietin could protect periodontal ligament stem cells from inflammatory microenvironment, which provided a novel theory for periodontal regeneration.

Osteogenic differentiation of periodontal membrane stem cells in inflammatory environments

Periodontitis is a common disease that is difficult to treat, and if not controlled in time, it causes severe conditions, such as alveolar bone resorption and tooth loosening and loss. Periodontal ligament stem cells constitute a promising cell source for regenerative treatment of periodontitis due to their high osteogenic differentiation capacity. PDLSC osteogenesis plays a central role in periodontal regeneration through successive cytokine-mediated signaling pathways and various biochemical and physicochemical factors. However, this process is inhibited in the inflammatory periodontitis environment due to high concentrations of lipopolysaccharide. Here, we review the mechanisms that influence the osteogenic differentiation of periodontal stem cells in this inflammatory microenvironment.

Botanicals and Oral Stem Cell Mediated Regeneration: A Paradigm Shift from Artificial to Biological Replacement

Stem cells are a well-known autologous pluripotent cell source, having excellent potential to develop into specialized cells, such as brain, skin, and bone marrow cells. The oral cavity is reported to be a rich source of multiple types of oral stem cells, including the dental pulp, mucosal soft tissues, periodontal ligament, and apical papilla. Oral stem cells were useful for both the regeneration of soft tissue components in the dental pulp and mineralized structure regeneration, such as bone or dentin, and can be a viable substitute for traditionally used bone marrow stem cells. In recent years, several studies have reported that plant extracts or compounds promoted the proliferation, differentiation, and survival of different oral stem cells. This review is carried out by following the PRISMA guidelines and focusing mainly on the effects of bioactive compounds on oral stem cell-mediated dental, bone, and neural regeneration. It is observed that in recent years studies were mainly focused on the utilization of oral stem cell-mediated regeneration of bone or dental mesenchymal cells, however, the utility of bioactive compounds on oral stem cell-mediated regeneration requires additional assessment beyond in vitro and in vivo studies, and requires more randomized clinical trials and case studies.

Validation of the traditional medicinal use of a Mexican endemic orchid (Prosthechea karwinskii) through UPLC-ESI-qTOF-MS/MS characterization of its bioactive compounds

Ethnopharmacological relevance

The orchid Prosthechea karwinskii is a medicinal orchid in Oaxaca, Mexico, used to treat diabetes, cough, wounds, and burns, prevent miscarriage and assist in labor. Each part of the plant (leaves, pseudobulbs, or flowers) is used by healers for certain treatment conditions, indicating that each part has different biocompounds with specific pharmacological activity.

Aim of the study

To characterize the biocompounds in extracts from leaves, pseudobulbs, and flowers of P. karwinskii and evaluate their ROS inhibition capacity to associate it with medicinal uses.

Materials and methods

The compounds present in extracts from leaves, pseudobulbs, and flowers of P. karwinskii were identified by UPLC-ESI-qTOF-MS/MS. The chemical differentiation of each extract was tested by principal component analysis (PCA) using compound intensity values. For each extract, total phenol and flavonoid contents were quantified. Their antioxidant capacity was evaluated ex vivo by inhibition of ROS with DCFH-DA and in vitro with DPPH radical.

Results

Based on the PCA, it was observed that some compounds were completely separated from others according to the correlation that they presented. The compounds common to all three plant parts were quinic, malic, succinic, azelaic, and pinellic acids. Among the compounds identified, two were exclusive to leaves, four to pseudobulbs, and ten to flowers. Some of the identified compounds have well-known antioxidant activity. The leaves had the highest content of total phenols and flavonoids, and the highest in vitro and ex vivo antioxidant capacity. A strong correlation was observed between phenol and flavonoid contents, and antioxidant capacity ex vivo and in vitro.

Conclusions

It was found that the bioactive compounds and antioxidant capacity of each part of the plant were associated with its traditional medicinal use. A pharmacological potential was also found in P. karwinskii for further biological studies because of the type of compounds it contained.

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Compounds common and specific to each plant part were identified by UPLC-ESI-qTOF-MS/MS.

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The biological activities reported for the identified compounds validate the traditional medicinal use of P. karwinskii.

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Embelin (inflammation) is exclusive to leaves, phloridzin (diabetes) to pseudobulbs, and abscisic acid (in labor) to flowers.

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In the literature, the antioxidant compounds are rutin, kaempferol-3-O-rutinoside, embelin, guanosine, and azelaic acid.

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Pearson's correlation coefficients indicate that a higher content of phenols and flavonoids has a higher antioxidant capacity.

Regulation of osteogenic differentiation by the pro-inflammatory cytokines IL-1β and TNF-α: current conclusions and controversies

Treatment of complex bone fracture diseases is still a complicated problem that is urged to be solved in orthopedics. In bone tissue engineering, the use of mesenchymal stromal/stem cells (MSCs) for tissue repair brings hope to the medical field of bone diseases. MSCs can differentiate into osteoblasts and promote bone regeneration. An increasing number of studies show that the inflammatory microenvironment affects the osteogenic differentiation of MSCs. It is shown that TNF-α and IL-1β play different roles in the osteogenic differentiation of MSCs via different signal pathways. The main factors that affect the role of TNF-α and IL-1β in osteogenic differentiation of MSCs include concentration and the source of stem cells (different species and different tissues). This review in-depth analyzes the roles of pro-inflammatory cytokines in the osteogenic differentiation of MSCs and reveals some current controversies to provide a reference of comprehensively understanding.

Rutin-Zn(II) complex promotes bone formation - A concise assessment in human dental pulp stem cells and zebrafish

We have assessed the molecular role of Rutin and rutin-Zn(II) complex on osteoblast differentiation and mineralization in human dental pulp cells and zebrafish model. The biocompatibility of the rutin-Zn(II) complex was determined using MTT and chick embryotoxicity assays. Alizarin red staining and ALP measurements were performed to study the osteogenic role of Rutin and rutin-Zn(II) complex at the cellular level in hDPSCs. At molecular level, following rutin and rutin-Zn(II) exposure, the mRNA expression profile of osteoblast markers such Runx2, type 1 col, OC, and ON were investigated. In addition to this, the expression of negative regulators of osteoblast development such Smad7, Smurf1, and HDAC7 waere studied by Real time RT-PCR analysis. The osteogenic role of prepared complex under in vivo was studied by an in-house zebrafish scale model followed by osteoblast differentiation markers expression profiling and Ca:P level measurement by ICP-MS. Rutin and the rutin-Zn(II) complex were found to be non-toxic till 10 μM and increased the expression of osteoblast differentiation marker genes. It also enhanced calcium deposition in both in vitro and in vivo models. Osteogenic property of rutin-Zn(II) in hDPSCs was found be mediated by Smad7, Smurf1, and HDAC7 and enhancing Runx2 expression. Our study warrants the possible use of rutin-Zn(II) as naïve agent or in combination with other bone scaffolding systems/materials for bone tissue engineering applications.

Human periodontal ligament stem cells and hormesis: Enhancing cell renewal and cell differentiation

This paper provides a detailed assessment of hormetic dose responses by human periodontal ligament stem cells (hPDLSCs). Hormetic dose responses were induced by a broad range of chemicals, including dietary supplements (e.g., curcumin, ginsenoside Rg1), pharmaceutical/commercial substances (e.g., metformin) and endogenous agents (e.g., periostin, TNF-α) for cell proliferation/viability and osteogenic/adipocyte differentiation. This paper clarifies underlying mechanistic foundations of the hPLDSC hormetic dose responses and explores their therapeutic implications. Emerging evidence based on assessments of multiple types of stem cells shows hormetic dose responses to be widespread, reflecting considerable generality and a highly conserved evolutionary trait.

Dental-Derived Mesenchymal Stem Cells: State of the Art

Mesenchymal stem cells (MSCs) could be identified in mammalian teeth. Currently, dental-derived MSCs (DMSCs) has become a collective term for all the MSCs isolated from dental pulp, periodontal ligament, dental follicle, apical papilla, and even gingiva. These DMSCs possess similar multipotent potential as bone marrow-derived MSCs, including differentiation into cells that have the characteristics of odontoblasts, cementoblasts, osteoblasts, chondrocytes, myocytes, epithelial cells, neural cells, hepatocytes, and adipocytes. Besides, DMSCs also have powerful immunomodulatory functions, which enable them to orchestrate the surrounding immune microenvironment. These properties enable DMSCs to have a promising approach in injury repair, tissue regeneration, and treatment of various diseases. This review outlines the most recent advances in DMSCs' functions and applications and enlightens how these advances are paving the path for DMSC-based therapies.

Periodontal ligament stem cells in the periodontitis niche: inseparable interactions and mechanisms

Periodontitis is characterized by the periodontium's pathologic destruction due to the host's overwhelmed inflammation to the dental plaque. The bacterial infections and subsequent host immune responses have shaped a distinct microenvironment, which generally affects resident periodontal ligament stem cells (PDLSCs). Interestingly, recent studies have revealed that impaired PDLSCs may also contribute to the disturbance of periodontal homeostasis. The putative vicious circle underlying the interesting "positive feedback" of PDLSCs in the periodontitis niche remains a hot research topic, whereas the inseparable interactions between resident PDLSCs and the periodontitis niche are still not fully understood. This review provides a microscopic view on the periodontitis progression, especially the quick but delicate immune responses to oral dysbacterial infections. We also summarize the interesting crosstalk of the resident PDLSCs with their surrounding periodontitis niche and potential mechanisms. Particularly, the microenvironment reduces the osteogenic properties of resident PDLSCs, which are closely related to their reparative activity. Reciprocally, these impaired PDLSCs may disrupt the microenvironment by aggravating the host immune responses, promoting aberrant angiogenesis, and facilitating the osteoclastic activity. We further recommend that more in-depth studies are required to elucidate the interactions of PDLSCs with the periodontal microenvironment and provide novel interventions for periodontitis.

Systems pharmacology-based dissection of mechanisms of Tibetan medicinal compound Ruteng as an effective treatment for collagen-induced arthritis rats

ETHNOPHARMACOLOGICAL RELEVANCE

Compound Ruteng (CRT) is a prescribed formulation based on the theory of Tibetan medicine for the treatment of yellow-water-disease. It is consisted with 7 medicinal material include Boswellia carterii Birdw (named "Ruxiang" in Chinese); Tinospora sinensis (Lour.) Merr. (named "Kuan-Jin-Teng" in Chinese), Cassia obtusifolia L (named "Jue-Ming-Zi" in Chinese); Abelmoschus manihot (L.) Medic (named "Huang-Kui-Zi" in Chinese); Terminalia chebula Retz. (named "He-Zi" in Chinese); Lamiophlomis rotata (Benth.) Kudo (named "Du-Yi-Wei" in Chinese) and Pyrethrum tatsienense (Bur. et Franch.) Ling (named "Da-Jian-Ju" in Chinese). They are widely distributed in Tibet area of China and have been used to treat rheumatism, jaundice, and skin diseases for centuries.

AIM OF THE STUDY

The present study was conducted to investigate the anti-arthritis effect of CRT and to disclose the systems pharmacology-based dissection of mechanisms.

MATERIALS AND METHODS

The chemical constituents in CRT were identified using HPLC method, and CRT candidate targets against RA were screened by network pharmacology-based analysis and further experimentally validated based on collagen-induced arthritis (CIA) rat model. Furthermore, therapeutic mechanisms and pathways of CRT were investigated.

RESULTS

391 potential targets (protein) were predicted against 92 active ingredients of 7 medicinal materials in CRT. Enrichment analysis and molecular docking studies also enforced the practiced results. X-ray based physiological imaging showed the attenuated effect of CRT on paw swelling, synovial joints and cartilage with improved inflammation in CIA rats. Moreover, the expression of biomarkers associated with RA such as MMP1, MMP3 and MMP13 and TNF-a, COX2 and iNOS are down-regulated in ankle joints, serum, or liver.

CONCLUSION

In conclusion, CRT compound could attenuate RA symptoms and active ingredients of this compound could be considered for drug designing to treat RA.

Effect of TNF-α on the proliferation and osteogenesis of human periodontal mesenchymal stem cells

The aim of the present study was to investigate the effect of tumor necrosis factor-α (TNF-α) on the proliferation and osteogenesis of human periodontal mesenchymal stem cells (hPDLSCs). Antigen expression in hPDLSCs was detected by flow cytometry. hPDLSCs were divided into four groups: A control group with no TNF-α treatment, and three experimental groups treated with 0.1, 1 and 10 ng/ml TNF-α, respectively. The effect of TNF-α on proliferation of hPDLSCs in vitro was detected using a Cell Counting Kit-8 assay. Differentiation into an osteogenic lineage was detected by alkaline phosphatase sand alizarin red staining, and the mRNA and protein expression levels of runt-related transcription factor 2 (Runx2), osteocalcin (OCN) and type I collagen (Col-I) were detected using reverse transcription-quantitative PCR and western blot respectively. Following treatment with 10 ng/ml TNF-α, proliferation was significantly increased compared with an untreated control group (P<0.01). Additionally, there was a significant inhibition of alkaline phosphatase enzyme activity, alizarin red mineralization node size, and in the gene and protein expression levels of osteogenic differentiation markers, including Runx2, OCN and COL-I (all, P<0.05). Taken together, the results indicated that treatment with 10 ng/ml TNF-α promoted the proliferation of hPDLSCs in vitro and inhibited osteogenic differentiation of hPDLSCs, providing an experimental basis for regulation of hPDLSC-mediated periodontal tissue regeneration.

Effects of rutin on osteoblast MC3T3-E1 differentiation, ALP activity and Runx2 protein expression

As a flavonoid, rutin has been found to have a wide range of biological functions, such as resisting inflammation and oxidation, and preventing cerebral hemorrhage and hypertension. It has been found to play an important role in osteoporosis and other orthopedic diseases in recent years. MC3T3-E1 cells were randomly divided into a control group, a rutin-1 group (0.01 mmol/L), a rutin-2 group (0.05 mmol/L) and a rutin-3 group (0.1 mmol/L). Osteogenic differentiation of cells was induced by osteogenic induction fluid. The control group was treated with the maximum dose of drug solvent. 2~3 days later, the solvent was replaced with fresh osteogenic induction fluid containing rutin. After a certain period of routine culture, the cells were collected for subsequent experiments. The expression of Runx2 gene in cells in all groups was detected by Real-time PCR; the expression of Runx2 protein was detected by Western blot and immunocytochemistry (IHC); the activity of ALP was detected by reagent kit method; osteogenic differentiation was analyzed by alizarin red staining. The results of Real-time PCR showed that, compared with the control group, the treatment of cells with rutin can significantly increase the expression of Runx2 gene (p<0.05); the higher the concentration, the higher the expression of Runx2 gene, and significant differences were found among groups in which different concentrations were used (p<0.05); the results of Western blot and IHC showed that the expression trend of Runx2 protein in each group was consistent with PCR results. In drug treatment groups, the activity of ALP was significantly higher than that in the control group (p<0.05); there were significant differences among groups in which different concentrations were used (p<0.05). The results of alizarin red staining showed that calcified nodules were formed in all groups and that the area of calcified nodules formed in groups treated with rutin was greater than that in the control group; the greater the concentration, the larger the area. Rutin can promote osteoblastic differentiation; and the greater the concentration, the more effective it is.

miR-23b mediates TNF-α-Inhibited Osteogenic Differentiation of Human Periodontal Ligament Stem Cells by Targeting Runx2

Periodontitis is the most prevalent oral infection disease, which causes the destruction of periodontal supporting tissues and eventual tooth loss. This study aimed to investigate the molecular mechanism of miRNA-23b (miR-23b) in regulating the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) in an inflammatory environment. Results revealed that tumor necrosis factor-α (TNF-α), a notoriously inflammatory cytokine, remarkably attenuated the osteogenic differentiation of hPDLSCs, which were partially rescued by SKL2001 (Wnt/β-catenin agonist). We further explored the underlying roles of miRNAs involved in TNF-α-inhibited osteogenesis of hPDLSCs. The miR-23b significantly increased with TNF-α stimulation, which was abolished by SKL2001. Similar to the effect of TNF-α, miR-23b agonist (agomir-23b) dramatically reduced the expression of runt-related transcription factor 2 (Runx2) and suppressed the osteogenic differentiation of hPDLSCs. The inhibition of miR-23b significantly increased Runx2, which is the major transcription factor during osteogenesis, thereby indicating that miR-23b was an endogenous regulator of Runx2 in hPDLSCs. Bioinformatic analysis and dual luciferase reporter assays confirmed that Runx2 was a target gene of miR-23b. Furthermore, the gain function assay of Runx2 revealed that the Runx2 overexpression efficiently reversed the suppression of the osteogenic differentiation of hPDLSCs with miR-23b agonist, suggesting that the suppressing effect of miR-23b on osteogenesis was mediated by Runx2 inhibition. Our study clarified that miR-23b mediated the TNF-α-inhibited osteogenic differentiation of hPDLSCs by targeting Runx2. Therefore, the expanded function of miR-23b in the osteogenesis of hPDLSCs under inflammatory conditions. This study might provide new insights and a novel therapeutic target for periodontitis.

Cynaroside protects human periodontal ligament cells from lipopolysaccharide-induced damage and inflammation through suppression of NF-κB activation

OBJECTIVE

To investigate whether cynaroside protects human periodontal ligament (hPDL) cells from lipopolysaccharide (LPS)-induced damage and inflammation and to analyze the underlying mechanism.

METHODS

LPS was used to stimulate hPDL and RAW264.7 cells. MTT assay was used to detect cell viability, and protein expression levels were measured via western blot analysis. Nitrite oxide and prostaglandin E₂ were used to quantify the inflammatory response. Alizarin Red S staining was used to detect mineralized nodules.

RESULTS

Cynaroside inhibited the expression of iNOS, COX-2, TNF-α, and IL-6 in LPS-stimulated hPDL and RAW264.7 cells without cytotoxicity. Furthermore, cynaroside significantly suppressed LPS-induced protein expression of matrix metalloproteinase 3. Additionally, cynaroside prevented LPS-induced NF-κB p65 subunit translocation to the nucleus by inhibiting the phosphorylation and degradation of IκB-α. Moreover, cynaroside could restore the mineralization ability of hPDL cells reduced by LPS.

CONCLUSION

Cynaroside protected hPDL cells from LPS-induced damage and inflammation via inhibition of NF-κB activation. These results suggest that cynaroside may be a potential therapeutic agent for the alleviation of periodontitis.

Exosomes derived from P2X7 receptor gene-modified cells rescue inflammation-compromised periodontal ligament stem cells from dysfunction

Although cellular therapy has been proposed for inflammation‐related disorders such as periodontitis for decades, clinical application has been unsuccessful. One explanation for these disappointing results is that the functions of stem cells are substantially compromised when they are transplanted into an inflammatory in vivo milieu. Considering the previous finding that P2X7 receptor (P2X7R) gene modification is able to reverse inflammation‐mediated impairment of periodontal ligament stem cells (PDLSCs), we further hypothesized that cells subjected to P2X7R gene transduction also exert influences on other cells within an in vivo milieu via an exosome‐mediated paracrine mechanism. To define the paracrine ability of P2X7R gene‐modified cells, P2X7R gene‐modified stem cell‐derived conditional medium (CM‐Ad‐P2X7) and exosomes (Exs‐Ad‐P2X7) were used to incubate PDLSCs. In an inflammatory osteogenic microenvironment, inflammation‐mediated changes in PDLSCs were substantially reduced, as shown by quantitative real‐time PCR (qRT‐PCR) analysis, Western blot analysis, alkaline phosphatase (ALP) staining/activity assays, and Alizarin red staining. In addition, the Agilent miRNA microarray system combined with qRT‐PCR analysis revealed that miR‐3679‐5p, miR‐6515‐5p, and miR‐6747‐5p were highly expressed in Exs‐Ad‐P2X7. Further functional tests and luciferase reporter assays revealed that miR‐3679‐5p and miR‐6747‐5p bound directly to the GREM‐1 protein, while miR‐6515‐5p bound to the GREM‐1 protein indirectly; these effects combined to rescue inflammation‐compromised PDLSCs from dysfunction. Thus, in addition to maintaining their robust functionality under inflammatory conditions, P2X7R gene‐modified stem cells may exert positive influences on their neighbors via a paracrine mechanism, pointing to a novel strategy for modifying the harsh local microenvironment to accommodate stem cells and promote improved tissue regeneration.

Identification of blood-activating components from Xueshuan Xinmaining Tablet based on the spectrum-effect relationship and network pharmacology analysis

With the aim of identifying the active components of Xueshuan Xinmaining Tablet (XXT) and discussing the potential mechanism involved, the relationship between HPLC fingerprints and its blood-activating effect were established by multivariate statistical analysis, including gray relational analysis (GRA) and partial least squares regression analysis (PLSR). Network pharmacology was used to predict the potential mechanism based on the identified active components. GRA and PLSR analysis showed close correlation between the HPLC fingerprints and blood-activating activity, and peaks P1, P3, P11, P15, P22, P34, P36, P38 and P39 might be potential anti-blood stasis components of XXT. The pharmacological verification showed that salvianic acid A (P1), rutin (P3), ginsenoside Rg1 (P11) and Rb1 (P22), cinobufagin (P36), and tanshinone I (P38) and IIA (P39) had significant blood-activating effects. Based on these seven active compounds, network pharmacology analysis indicated that the anti-blood stasis effect of XXT might be closely related to TNF, PI3K-Akt and NF-κB signaling pathways. The spectrum-effect relationship of XXT was successfully established in this study. The blood-activating components and the anti-blood stasis mechanism were revealed and predicted. These findings could also be beneficial for an exploration of the active components of TCM.