Cullin3 aggravates the inflammatory response of periodontal ligament stem cells via regulation of SHH signaling and Nrf2

ATF3 affects osteogenic differentiation in inflammatory hPDLSCs by mediating ferroptosis via regulating the Nrf2/HO-1 signaling pathway

Activating transcription factor 3 (ATF3) has been identified as a regulator associated with osteoblast differentiation. However, the effects of ATF3 on the osteogenic differentiation and proliferation of human periodontal stem cells (hPDLSCs) in periodontitis have not been reported. With the purpose of establishing an in vitro model of periodontitis, hPDLSCs were challenged with lipopolysaccharide (LPS). The Cell Counting Kit-8 assay was applied to assess cell viability, while reverse transcription-quantitative PCR and western blotting were employed to detect ATF3 expression. Inflammatory release was assessed using ELISA, together with western blotting. Lipid peroxidation was explored using the C11 BODIPY 581/591 probe, biochemical kits, thiobarbituric acid reactive substances (TBARS) assay and DCFH-DA staining. Iron and Fe2+ levels, and the expression levels of ferroptosis-related proteins were measured using corresponding kits and western blotting. Osteogenic differentiative capability was evaluated using alkaline phosphatase staining, Alizarin red staining and western blotting. The expression levels of proteins associated with Nrf2/HO-1 signaling were identified using western blotting. The results indicated that ATF3 expression was upregulated in LPS-induced hPDLSCs. The knockdown of ATF3 alleviated the LPS-induced inflammatory response in hPDLSCs, together with increased levels of TNF-α, IL-6, IL-1β, Cox-2 and iNOS, and decreased levels of IL-10. ATF3 silencing also led to lower TBARS production rate, and reduced levels of reactive oxygen species, iron, Fe2+, ACSL4 and TFR1, whereas it elevated the levels of SLC7A11 and GPX4. In addition, ATF3 silencing promoted hPDLSC mineralization and cell differentiation, and elevated the levels of OCN2, RUNX2 and BMP2. Additionally, ATF3 depletion upregulated the expression levels of proteins related with Nrf2/HO-1 signaling. The Nrf2 inhibitor ML385 partially counteracted the effects of ATF3 interference on the LPS-challenged inflammatory response, lipid peroxidation, ferroptosis as well as osteogenic differentiative capability in hPDLSCs. In summary, the results revealed that ATF3 silencing suppressed inflammation and ferroptosis, while it improved osteogenic differentiation in LPS-induced hPDLSCs by regulating Nrf2/HO-1 signaling, which may provide promising therapeutic targets for the treatment of periodontitis.

Brazilin cream from Caesalpinia sappan inhibit periodontal disease: in vivo study

Background

Gingivitis is an inflammation of the gums that is the initial cause of the development of periodontal disease by the activity of Nuclear Factor-kappa B (NF-κB), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), p38, and Tumor Necrosis Factor-α (TNF-α). Unaddressed chronic inflammation can lead to persistent disturbances in other parts of the body. Brazilin is a naturally occurring plant chemical that may have antibacterial and anti-inflammatory effects. Treatment based on the natural plant compound, brazilin, is developed in the form of a topical cream for easy application.

Objective

The aim is to develop the natural compound brazilin in the form of a topical cream as an anti-inflammatory agent to reduce NF-κB expression through Imunohistochemistry (IHC) methods, and the expression of pro-inflammatory genes IL-1β, IL-6, p38, and TNF-α.

Methods

Male Sprague-Dawley rats were induced with gingivitis using P. gingivalis bacteria. The observed groups included rats treated with a single application of brazilin cream and rats treated with two applications of brazilin cream. The treatment was administered for 15 days. On days 3, 6, 9, 12, and 15, anatomical wound observations and wound histology using hematoxylin-eosin and Masson's Trichrome staining were performed. NF-κB protein expression was analyzed using the IHC method. Gingival inflammation gene expression of NF-κB, IL-1β, IL-6, p38, and TNF-α was measured using q-RTPCR.

Results

Single and double applications of brazilin cream increased angiogenesis and decreased NF-κB protein expression, in addition to the IL-1β, IL-6, p38, and TNF-α gene expressions.

Conclusion

In a rat gingivitis model, Brazilin cream may function as an anti-inflammatory agent in the gingival tissue.

MicroRNA-671-5p regulates the inflammatory response of periodontal ligament stem cells via the DUSP8/p38 MAPK pathway

BACKGROUND

MicroRNAs are differentially expressed in periodontitis tissues. They are involved in cellular responses to inflammation and can be used as markers for diagnosing periodontitis. Microarray analysis showed that the expression level of microRNA-671-5p in periodontal tissues of patients with periodontitis was increased. In this study, we investigated the mechanism of action of microRNA-671-5p in human periodontal ligament stem cells (hPDLSCs) under inflammatory conditions.

METHODS AND RESULTS

HPDLSCs were treated with lipopolysaccharide (LPS) to establish an inflammation model. The cell survival rate was determined using the cell counting kit-8 (CCK8). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analyses were used to detect the expression of microRNA-671-5p and dual-specificity phosphatase (DUSP) 8 proteins, respectively, Interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were detected using qRT-PCR and Enzyme-linked immunosorbent assay (ELISA). A dual-luciferase reporter system was employed to determine the relationship between micoRNA-671-5p and DUSP8 expression. Activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway was confirmed using western blot analysis. Following the treatment of hPDLSCs with LPS, the expression levels of microRNA-671-5p in hPDLSCs were increased, cell viability decreased, and the expression of inflammatory factors displayed an increasing trend. MicroRNA-671-5p targets and binds to DUSP8. Silencing microRNA-671-5p or overexpressing DUSP8 can improve cell survival rate and reduce inflammatory responses. When DUSP8 was overexpressed, the expression of p-p38 was reduced.

CONCLUSIONS

microRNA-671-5p targets DUSP8/p38 MAPK pathway to regulate LPS-induced proliferation and inflammation in hPDLSCs.

Astragaloside reduces toxic effect of periodontal ligament fibroblasts induced by lipopolysaccharide

Periodontitis is a non-specific and chronic disease which is highly prevalent, resulting in inflammation and destruction of periodontal tissues. This study aims to explore the effect and mechanism of astragaloside on periodontitis. We used CCK-8, Western Blot, qPCR and flow cytometry to analyze cell viability, related protein and mRNA expression, and cell apoptosis. We found that AST could promote cell proliferation and reduce apoptosis induced by LPS. Besides, AST could alleviate the increased expression of COX-2 and ICAM-1 induced by LPS. MiR-26b-3P specifically targeted the 3' UTR of ICAM-1. These results indicate that AST reduces toxic effect of human periodontal ligament cells through regulating miR-26b-3P/ICAM-1, thus highlighting its protective role in periodontitis.

The Role of Cullin 3 in Cerebral Ischemia-Reperfusion Injury

Cullin 3 (CUL3), a member of Cullin-RING ubiquitin ligase family, regulates multiple intracellular pathways. CUL3 expression in peripheral immune cells is highly associated with the development of stroke, while little is known about the mechanism of how CUL3 participates in cerebral ischemia/reperfusion (I/R) injury. In this study, we showed that CUL3 was obviously upregulated in brain tissues of male rats received middle cerebral artery occlusion (MCAO) and reperfusion and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neurons. We firstly confirmed that CUL3 interacted with WNK3, a protein that has been proved to be associated with brain damage after ischemic stroke. CUL3 knockdown inhibited the ubiquitination of WNK3 and accelerated the phosphorylation of OSR1 in OGD/R-stimulated neurons. CUL3 silencing did not further aggravate cerebral I/R injury and played a neuroprotective role in vitro and in vivo. CUL3 knockdown attenuated the impairment of cell viability caused by OGD/R. CUL3 silencing reduced TUNEL-positive cells, down-regulated pro-apoptotic factor (Bax and Cleaved caspase 3) levels and increased the anti-apoptotic factor (Bcl-2) level in vitro and in vivo, suggesting that CUL3 repression alleviated neuronal apoptosis. Interestingly, rescue experiments revealed that WNK3 downregulation did not block the neuroprotection of CUL3 inhibition. These findings suggested that CUL3-mediated cerebral I/R injury might be not achieved through WNK3 signaling but other pathways. Furthermore, CUL3 inhibition suppressed ubiquitin-mediated degradation of Nrf2 and activated Nrf2 signaling by increasing the nuclear translocation of Nrf2 and expression levels of HO-1 and NQO-1. Taken together, CUL3 exacerbates cerebral I/R injury potentially due to its negative regulation of Nrf2 activation.

The role of Nrf2 in periodontal disease by regulating lipid peroxidation, inflammation and apoptosis

Nuclear factor E2-related factor 2(Nrf2) is a transcription factor that mainly regulates oxidative stress in the body. It initiates the expression of several downstream antioxidants, anti-inflammatory proteins and detoxification enzymes through the Kelch-like ECH-associating protein 1 (Keap1) -nuclear factor E2-related factor 2(Nrf2) -antioxidant response element (ARE) signaling pathway. Its anti-apoptosis, anti-oxidative stress and anti-inflammatory effects have gradually become the focus of periodontal disease research in recent years. In this paper, the structure and function of Nrf2 pathway and its mechanism of action in the treatment of periodontitis in recent years were analyzed and summarized, so as to further clarify the relationship between Nrf2 pathway and oxidative stress in the occurrence and development of periodontitis, and to provide ideas for the development of new treatment drugs targeting Nrf2 pathway.

MicroRNA-28-5p as a potential diagnostic biomarker for chronic periodontitis and its role in cell proliferation and inflammatory response

Background/purpose

Recent studies have pointed to the crucial role of microRNAs (miRNAs) in chronic periodontitis (CP). This study investigated the regulation and potential mechanisms of miR-28-5p in CP patients and lipopolysaccharide (LPS)-induced periodontal ligament cells (PDLCs).

Materials and methods

76 CP patients and 71 periodontally healthy subjects were included. RT-qPCR was employed to examine miR-28-5p and sphingosine kinase −1 (SPHK1) in subjects’ gingival sulcus fluid and PDLCs. The diagnostic performance was evaluated by measuring the area under the curve (AUC) of the receiver operating characteristic (ROC) analysis. Pearson correlation coefficient (r) was adopted to explore the statistical relation between indicators. PDLCs proliferation and inflammation factors were determined by CCK-8 and ELISA assay. The direct target gene was validated by a dual-luciferase reporter assay.

Results

miR-28-5p was lowly expressed in CP patients and LPS-induced PDLCs (P < 0.05). AUC for miR-28-5p was 0.937, which had certain diagnostic value. Additionally, miR-28-5p was negatively correlated with periodontal clinical indicators and inflammatory factors. Cell proliferation of PDLCs was inhibited and inflammation was promoted under LPS induction, however, elevated miR-28-5p diminished the effect of LPS (P < 0.05). SPHK1 acts as a miR-28-5p target and the elevation of SPHK1 caused by LPS treatment was inhibited by the increased miR-28-5p.

Conclusion

Present study revealed that miR-28-5p could be served as a potential diagnostic biomarker for CP. And miR-28-5p may participate in CP progression by targeting SPHK1 to regulate the proliferation and inflammation of PDLCs. This study may offer insights into CP treatment and diagnosis.

Effects of nuclear factor-κB signaling pathway on periodontal ligament stem cells under lipopolysaccharide-induced inflammation

Lipopolysaccharide (LPS) induces inflammatory stress and apoptosis. This study focused on the effect of nuclear factor kappa B (NF-κB) signaling pathway on proliferation and osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) after LPS induction and its mechanism. We first isolated hPDLSCs from human tooth root samples in vitro. Then, flow cytometry detected positive expression of cell surface antigens CD146 and STRO-1 and negative expression of CD45, suggesting the hPDLSCs were successfully isolated. LPS significantly induced increased apoptosis and diminished proliferation of hPDLSCs. The NF-κB pathway agonist phorbol 12-myristate 13-acetate (PMA) or p65 overexpression inhibited the proliferation of LPS-treated hPDLSCs and promoted apoptosis. PMA also promoted LPS-induced up-regulation of the expression of inflammatory factors TNF-α and IL-6 and down-regulation of the expression of anti-inflammatory factor IL-10. Additionally, LPS was confirmed to lead to a reduction of alkaline phosphatase (ALP) activity, calcium nodules, and expression of osteogenic markers Runt-related transcription factor 2 (Runx2) and osteopontin. This reduction could be promoted by PMA. Western blotting further indicated that PMA could promote LPS-induced decrease of expression of p65 (cytoplasm), and total cellular proteins IKKα and IKKβ in hPDLSCs, while protein expression of p-IκBα (cytoplasm) and p65 (nucleus), and p-IκBα/IκBα ratio was elevated. By contrast, inhibition of the NF-κB pathway (PDTC) or small-interfering RNA targeting NF-κB/p65 (p65 siRNA) showed the opposite results. In conclusion, activation of NF-κB signaling in LPS-induced inflammatory environment can inhibit the proliferation and osteogenic differentiation of hPDLSCs. This study provides a theory foundation for the clinical treatment of periodontitis.

The role of long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (NEAT1) in chronic periodontitis progression

Long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) is a novel pro-inflammatory factor in severe human diseases. Since inflammatory plays important roles in periodontitis progression, we aimed to explore the role of NEAT1 in chronic periodontitis (CP) in vitro. We established a periodontitis cell model was established by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS)-induced periodontal ligament cells (PDLCs). Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to detect the expression of NEAT1, microRNA (miR)-200c-3p, and tumor necrosis factor receptor-associated factor 6 (TRAF6). Cell viability, inflammatory factors, and protein expression of Bcl-2, Bax, and TRAF6 were analyzed by MTT, enzyme-linked immunosorbent assay, and Western blot. The target relationships among NEAT1, miR-200c-3p, and TRAF6 were predicted by the StarBase/TargetScan software, and further validated by dual-luciferase reporter assay. In this research, NEAT1 is up-regulated in CP tissues and periodontitis model group. Silencing of NEAT1 and over-expression of miR-200c-3p enhanced cell viability and repressed apoptosis in the periodontitis model group. NEAT1 targets miR-200c-3p, and miR-200c-3p further targets TRAF6. MiR-200c-3p inhibitor or over-expression of TRAF6 reversed the promoting effect of NEAT1 knockdown on cell viability, and the inhibiting effects on inflammatory cytokines and cell apoptosis. Consequently, the silencing of NEAT1 inhibits inflammation and apoptosis via targeting miR-200c-3p/TRAF6 axis, thereby contributing to alleviate the progression of CP. This finding could provide an underlying target for the treatment of CP.

The Effects of Porphyromonas gingivalis on Inflammatory and Immune Responses and Osteogenesis of Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are increasingly used in tissue regeneration, not only because of their multilineage differentiation ability, but also because of their immunomodulatory function, which allows them to play a role in the inflammatory milieu, especially in periodontitis. Porphyromonas gingivalis (P. gingivalis) is an important pathogen associated with the progression of periodontitis. Heterogeneous MSC sources show differences in their inflammatory-immune responsiveness and osteogenesis capabilities when exposed to P. gingivalis and its virulence factors. This article reviews the promoted inflammatory and immune responses of periodontal ligament stem cells, which are potential pitfalls in bone regeneration. MSCs from other sources showed contradictory inflammatory and immune reactions in the few studies on this topic. We also summarize the mechanisms involved in the inflammatory, immune responses and osteogenic potential of MSCs exposed to P. gingivalis and its virulence factors to inform an improved utilization of MSCs in regenerative therapies for periodontitis.

Dexmedetomidine improves oxygen-glucose deprivation/reoxygenation (OGD/R) -induced neurological injury through regulating SNHG11/miR-324-3p/VEGFA axis

Dexmedetomidine (Dex) has been reported to exhibit neuroprotective effects through various regulatory mechanisms. This study aims to investigate the role and molecular mechanism of SNHG11 in Dex-mediated neuroprotection. The ischemic stroke (IS) model was established in vivo by middle cerebral artery occlusion (MCAO) and in vitro by oxygen-glucose deprivation and reperfusion (OGD/R)-treated SH-SY5Y. SNHG11 was highly expressed after OGD/R, and Dex improved OGD/R-induced neurological injury. Additionally, Dex reversed the effects of SNHG11 on OGD/R-induced neurological injury. Furthermore, we found that SNHG11 upregulated vascular endothelial growth factor A (VEGFA) expression by targeting miR-324-3p. Through rescue assays, it was confirmed that SNHG11 regulated OGD/R-induced neurological injury through increasing VEGFA expression. At last, Dex was also discovered to improve neurological injury through regulating SNHG11 in the rat model. In conclusion, our work demonstrated that Dex improved OGD/R-induced neurological injury via SNHG11/miR-324-3p/VEGFA axis. These findings may offer a novel therapeutic strategy for IS treatment.