Wnt antagonist secreted frizzled-related protein I (sFRP1) may be involved in the osteogenic differentiation of periodontal ligament cells in chronic apical periodontitis

Emerging therapeutic strategies targeting bone signaling pathways in periodontitis

Periodontitis is a multifactorial immune-mediated disease exacerbated by dysregulated alveolar bone homeostasis. Timely intervention is crucial for disease management to prevent tooth loss. To successfully manage periodontitis, it is imperative to understand the cellular and molecular mechanisms involved in its pathogenesis to develop novel treatment modalities. Non-surgical periodontal therapy (NSPT) such as subgingival instrumentation/debridement has been the underlying treatment strategy over the past decades. However, new NSPT approaches that target key signaling pathways regulating alveolar bone homeostasis have shown positive clinical outcomes. This narrative review aims to discuss endogenous bone homeostasis mechanisms impaired in periodontitis and highlight the clinical outcomes of preventive periodontal therapy to avoid invasive periodontal therapies. Although the anti-resorptive therapeutic adjuncts have demonstrated beneficial outcomes, adverse events have been reported. Diverse immunomodulatory therapies targeting the osteoblast/osteoclast (OB/OC) axis have shown promising outcomes in vivo. Future controlled randomized clinical trials (RCT) would help clinicians and patients in the selection of novel preventing therapies targeting key molecules to effectively treat or prevent periodontitis.

The influence of microorganisms on bone homeostasis in apical periodontitis

OBJECTIVE

This review aims to provide an overview of the role of microorganisms in the onset and progression of periapical diseases, particularly regarding their effects on bone homeostasis.

DESIGN

The search for this narrative review was conducted in PubMed, Web of Science and Google Scholar using relevant keywords, including checking reference lists of journal articles by hand searching.

RESULTS

Microorganisms directly promote osteoclasts through pathways such as nuclear factor-κB (NF-κB) and extracellular regulated protein kinases (ERK), while inhibiting osteoblasts function by interfering with the wingless-related integration site (Wnt)/β-catenin pathway in the periapical area. Moreover, microorganisms indirectly regulate periapical bone homeostasis by inducing programmed cell death and modulating the immune microenvironment through the activation of innate immunity via pattern-recognition receptors (PRRs) and subsequent cascades of responses. Among these microorganisms, Enterococcus faecalis, Porphyromonas gingivalis and Fusobacterium nucleatum play significant roles.

CONCLUSION

Microorganisms regulate pathways such as NF-ĸB and Wnt/β-catenin, as well as programmed cell death and the immune microenvironment in the periapical area, thereby disrupting bone homeostasis.

Exploring the molecular mechanism of estrogen therapy effectiveness after TCRA in IUA patients at single-cell level

BACKGROUND

Intrauterine adhesion (IUA) is a common cause of clinically refractory infertility, and there exists significant heterogeneity in the treatment outcomes among IUA patients with the similar severity after transcervical resection of adhesion(TCRA). The underlying mechanism of different treatment outcomes occur remains elusive, and the precise contribution of various cell subtypes in this process remains uncertain.

RESULTS

Here, we performed single-cell transcriptome sequencing on 10 human endometrial samples to establish a single-cell atlas differences between patients who responded to estrogen therapy and those who did not. The results showed increased infiltration of immune cells such as monocyte macrophages, T cells, and natural killer (NK) cells in patients who did not respond to estrogen therapy. Our findings indicate that distinct fibroblast subsets are implicated in the modulation of the Wnt, Hippo, and Hedgehog signaling pathways, as evidenced by functional enrichment analyses. This may have implications for the therapeutic efficacy in patients with IUA. Furthermore, we delineated the markers and transcriptional status of different macrophage subsets and identified two cell clusters, CXCL10high and CCL4L2high macrophage subsets, which are intimately associated with inflammation and fibrosis. The state of fibrosis and inflammatory response in human endometrial tissues with disparate treatment outcomes is revealed, and providing evidence to clarify the underlying determinants of sensitivity to estrogen therapy.

CONCLUSIONS

We described the transcriptional status of different cell subtypes in the two groups of patients, providing new ideas for exploring the molecular mechanism of the difference in the effectiveness of estrogen therapy in patients, and providing theoretical basis for providing precise and individualized treatment plans for IUA patients.

Genetic polymorphisms linked to extreme postorthodontic external apical root resorption in Koreans

BACKGROUND

External apical root resorption (EARR) is a common undesirable outcome of orthodontic treatment, this study aimed to identify genetic polymorphisms associated with the susceptibility to extreme orthodontic-induced EARR in a Korean population using extreme phenotype analysis sampling.

METHODS

Genomic DNA was isolated from the saliva of 77 patients who underwent orthodontic treatment involving two maxillary premolar extractions. The patients were divided into two groups based on EARR values measured on periapical radiographs: The significant resorption group (SG, EARR ≥ 4 mm) and the normal group (NG, EARR < 2 mm). In the NG group, patients with EARR < 1 mm were named the non-resorption group (NonG). Targeted next-generation sequencing was performed using the screened single nucleotide polymorphisms (SNPs), and firth logistic regression analysis was used to determine genetic associations with EARR. Haplotype-based association analysis was performed for specific SNPs.

RESULTS

SNPs related to genes TNFSF11, TNFRSF11B, WNT3A, SFRP2, LRP6, P2RX7, and LRP1 were found to be significantly associated with severe EARR (p < 0.05, pre-Bonferroni correction p-values). Additionally, the haplotype CCA of rs17525809, rs208294, and rs1718119 P2RX7 had a higher frequency in the SG group.

CONCLUSION

Extreme phenotype analysis has identified eleven SNPs related to genes TNFSF11, TNFRSF11B, WNT3A, SFRP2, LRP6, P2RX7, and LRP1 that are associated with severe root resorption in the Korean population. These findings will contribute to the development of predictive diagnostic tools for identifying severe root resorption that may occur during orthodontic treatment.

Hsa_circ_0001445 works as a cancer suppressor via miR-576-5p/SFRP1 axis regulation in ovarian cancer

BACKGROUND

Ovarian cancer (OC) has high mortality and morbidity. Circular RNA (circRNA) can deeply impact the tumor occurrence and growth. The pathogenic activity of one particular circRNA, hsa_circ_0001445 (hcR1445), in OC remains unclear and was therefore analyzed in this study.

METHODS

Human OC tissue specimens and cell lines (SKOV3, HO8910, and OVCAR8) were used to examine the levels of hcR1445 and the microRNA miR-576-5p using polymerase chain reaction. The 5-ethynyl-2'-deoxyuridine, flow cytometry, cellular scratch test, CCK-8, and Transwell migration assays were used to examine the biological activities of hcR1445 and miR-576-5p on cell apoptosis, invasion, migration, and proliferation in OC cells. Protein expression of WNT/β-catenin and secreted frizzled-related protein 1 (SFRP1) were tested using Western blot analysis. The potential interactions of miR-576-5p/SFRP1 and hcR1445/miR-576-5p were evaluated using a dual-luciferase report assay. The effect of hcR1445 on OC growth and metastasis was further determined using an OC tumor xenograft model in vivo.

RESULTS

hcR1445 level was declined in OC cells and tissues. hcR1445 reduced cellular invasion, proliferation, and migration by blocking the ability of miR-576-5p to upregulate SFRP1 expression and consequently prohibit WNT/β-catenin signal transduction. hcR1445 upregulation suppressed OC growth, development, and intraperitoneal metastasis in vivo.

CONCLUSION

hcR1445 acts an antioncogene by targeting the miR-576-5p/SFRP1 axis and blocking OC progression and development. Thus, hcR1445 may be employed as an indicator or a possible therapeutic target in OC patients.

Astragalus polysaccharides and astragaloside IV alleviate inflammation in bovine mammary epithelial cells by regulating Wnt/β-catenin signaling pathway

The Wnt/β-catenin signaling regulates cell renewal and repair and is closely associated with inflammation. Astragalus polysaccharides (APS) and astragaloside IV (AS-IV), which are the main active substances extracted from Radix Astragali, protect cells by regulating Wnt signaling in cells, exerting antiinflammatory, antioxidant, and antistress effects. However, the mechanisms by which APS and AS-IV interact with Wnt signaling to achieve their therapeutic effects in bovine mammary epithelial cells (BMECs) are not understood. In this study, we used lipopolysaccharide (LPS)-stimulated BMECs as an in vitro model of inflammation to investigate the effects of APS and AS-IV on Wnt signaling in inflamed BMECs. Drug concentrations were screened using the CCK-8 method, the effect on protein expression was analyzed using immunoblotting, the effect on inflammatory factors using enzyme-linked immunosorbent assay, and the effect on oxidative factors using enzyme labeling and flow cytometry. LPS activated the expression of inflammatory and oxidative factors in cells and inhibited Wnt/β-catenin signaling. APS and AS-IV antagonized the inhibitory effect of LPS, protecting BMECs. They inhibited the expression of the IL-6, IL-8, and TNF-α inflammatory factors, and that of the MDA oxidative factor, and activated Wnt signaling in LPS-stimulated BMECs. Silencing of β-catenin abolished the protective effect of APS and AS-IV against LPS-stimulated BMECs. Thus, APS and AS-IV mediate protective effects in inflammatory BMECs model through activation of the Wnt signaling pathway. Wnt signaling pathway is one of the targets of the inhibitory effects of APS and AS-IV on inflammation.

Mechanisms of bone remodeling and therapeutic strategies in chronic apical periodontitis

Chronic periapical periodontitis (CAP) is a typical oral disease in which periodontal inflammation caused by an odontogenic infection eventually leads to bone loss. Uncontrolled infections often lead to extensive bone loss around the root tip, which ultimately leads to tooth loss. The main clinical issue in the treatment of periapical periodontitis is the repair of jawbone defects, and infection control is the first priority. However, the oral cavity is an open environment, and the distribution of microorganisms through the mouth in jawbone defects is inevitable. The subversion of host cell metabolism by oral microorganisms initiates disease. The presence of microorganisms stimulates a series of immune responses, which in turn stimulates bone healing. Given the above background, we intended to examine the paradoxes and connections between microorganisms and jaw defect repair in anticipation of new ideas for jaw defect repair. To this end, we reviewed the microbial factors, human signaling pathways, immune cells, and cytokines involved in the development of CAP, as well as concentrated growth factor (CGF) and stem cells in bone defect repair, with the aim of understanding the impact of microbial factors on host cell metabolism to inform the etiology and clinical management of CAP.

Semaphorin 7A accelerates the inflammatory osteolysis of periapical lesions

INTRODUCTION

Semaphorin 7A (SEMA7A), the only member of the class VII semaphorin, has been considered as a potent immunomodulatory regulator, whose function in periapical lesions remains unclear. In our previous study, we found that SEMA7A was upregulated in human periapical periodontitis and might be involved in the immune response and tissue destruction of periapical lesions. In this research, we aimed to further explore the specifical regulatory role of SEMA7A as well as its regulatory mechanisms in the inflammatory progression of periapical lesions.

METHODS

Human periodontal ligament cells (hPDLCs) were collected from intact, caries-free, and healthy third molars and stimulated with recombinant human SEMA7A (rhSEMA7A). Real-time quantitative polymerase chain reaction (RT-qPCR), western blot and enzyme-linked immunosorbent assay (ELISA) were used to detect the mRNA and protein levels of inflammatory cytokines and matrix metalloproteinases (MMPs) in hPDLCs. 20 C57BL/6 mice were randomly divided into 4 groups: healthy control group, pulp exposure group, pulp exposure and saline treatment group and pulp exposure and rhSEMA7A treatment group. 20 μL sterile saline or 20 μL 200 ng/μL rhSEMA7A were injected respectively into the buccal mucosa around the root apex at day 0, 7, and 14. Mandibular tissues were collected at day 21. Micro-CT and immunohistochemical (IHC) staining were used to identify the bone destruction and inflammatory infiltration in periapical areas. Finally, AKT inhibitor (LY294002) was used to pretreat hPDLCs before rhSEMA7A stimulation to determine the role of AKT signaling activation in this process.

RESULTS

After treatment with rhSEMA7A, the mRNA and protein levels of interleukin (IL)-1β, IL-18, COX-2, MMP-1, and MMP-3 were remarkably upregulated in hPDLCs. In in vivo experiments, compared with other three groups, the treatment of rhSEMA7A would aggravate the osteolysis of alveolar bone and promote the infiltration of immune cells into the apex area accompanying with the increasing expression level of IL-1β, IL-18, matrix metalloproteinase (MMP)-1 and MMP-3. Furthermore, we found that the pro-inflammatory role of SEMA7A could be inhibited by the application of AKT inhibitor (LY294002).

CONCLUSION

SEMA7A likely aggravates the inflammatory reaction and bone destruction of existing periapical lesions. The pro-inflammatory role of SEMA7A in hPDLCs could partially be mediated through the ATK signaling transduction pathway.

Resveratrol prevents inflammation and oxidative stress response in LPS-induced human gingival fibroblasts by targeting the PI3K/AKT and Wnt/β-catenin signaling pathways

This study aimed to elucidate the anti-inflammatory and antioxidant properties of resveratrol (RSV) in human gingival fibroblasts (HGFs) following stimulation by P. gingivalis lipopolysaccharide (LPS). The levels of the inflammatory cytokines IL-1β, IL-6, IL-8 and TNFα, the activity of the antioxidant enzymes SOD and GSH-Px, and the levels of MDA, were evaluated by ELISA. It was observed that the expression of IL-1β, IL-6, IL-8 and TNFα in LPS-induced HGFs was significantly downregulated by RSV in a dose-dependent manner. RSV also partly increased oxidative stress (OS)-related factors, including SOD and GSH-Px, which was accompanied by a decrease in MDA production, although the results were not statistically significant. Additionally, RSV-induced deactivation of the PI3K/AKT and Wnt/β-catenin pathways in LPS-induced HGFs was observed by western blot analysis. Subsequently, it was demonstrated treatment with PI3K/AKT pathway inhibitor (LY294002) or Wnt/β-catenin pathway inhibitor (Dickkopf-1, DKK-1) could further enhance the anti-inflammatory and antioxidant effects of RSV by downregulating the expression of IL-1β, IL-6, IL-8 and TNFα, and the production of MDA, and increasing the activity of SOD and GSH-Px in LPS-induced HGFs. These results suggested RSV attenuated the inflammation and OS injury of P. gingivalis LPS-treated HGFs by deactivating the PI3K/AKT and Wnt/β-catenin signaling pathways.