Regulation of p53 under hypoxic and inflammatory conditions in periodontium

Regulation of Immune Inflammation and Promotion of Periodontal Bone Regeneration by Irisin-Loaded Bioactive Glass Nanoparticles

Clinical solutions of bone defects caused by periodontitis involve surgical treatment and subsequent anti-infection treatment using antibiotics. Such a strategy faces a key challenge in that the excessive host immune response results in the damage of periodontal tissues. Consequently, it is of great importance to develop novel periodontitis treatment that allows the regulation of the host immune response and promotes the generation of periodontal tissues. Irisin has a good bone regeneration ability and could reduce the inflammatory reaction by regulating the differentiation of macrophages. In this study, we loaded irisin onto bioactive glass nanoparticles (BGNs) to prepare a composite, irisin-BGNs (IR-BGNs) with anti-inflammatory, bacteriostatic, and tissue regeneration functions, providing a novel idea for the design of ideal materials for repairing oral tissue defects caused by periodontitis. We also verified that the IR-BGNs had better anti-inflammatory properties on RAW264.7 cells compared to irisin and BGNs alone. Strikingly, when hPDLCs were stimulated with IR-BGNs, they exhibited increased expression of markers linked to osteogenesis, ALP activity, and mineralization ability in comparison to the negative control. Furthermore, on the basis of RNA sequencing results, we validated that the p38 pathway can contribute to the osteogenic differentiation of the IR-BGNs. This work may offer new thoughts on the design of ideal materials for repairing oral tissue defects.

Mechanisms underlying the effects, and clinical applications, of oral microbiota in lung cancer: current challenges and prospects

The oral cavity contains a site-specific microbiota that interacts with host cells to regulate many physiological processes in the human body. Emerging evidence has suggested that changes in the oral microbiota can increase the risk of lung cancer (LC), and the oral microbiota is also altered in patients with LC. Human and animal studies have shown that oral microecological disorders and/or specific oral bacteria may play an active role in the occurrence and development of LC through direct and/or indirect mechanisms. These studies support the potential of oral microbiota in the clinical treatment of LC. Oral microbiota may therefore be used in the prevention and treatment of LC and to improve the side effects of anticancer therapy by regulating the balance of the oral microbiome. Specific oral microbiota in LC may also be used as screening or predictive biomarkers. This review summarizes the main findings in research on oral microbiome-related LC and discusses current challenges and future research directions.

Ferroptosis: A New Development Trend in Periodontitis

Periodontitis is a chronic inflammatory disease associated with bacterial biofilm. It is characterized by loss of periodontal support tissue and has long been considered as a "silent disease". Because it is difficult to prevent and has a health impact that can not be ignored, researchers have been focusing on a mechanism-based treatment model. Ferroptosis is an iron-dependent regulatory form of cell death, that directly or indirectly affects glutathione peroxidase through different signaling pathways, resulting in a decrease in cell antioxidant capacity, accumulation of reactive oxygen species and lipid peroxidation, which cause oxidative cell death and tissue damage. Recently, some studies have proven that iron overload, oxidative stress, and lipid peroxidation exist in the process of periodontitis. Based on this, this article reviews the relationship between periodontitis and ferroptosis, in order to provide a theoretical reference for future research on the prevention and treatment of periodontal disease.

S, Torabi M, Mohammadi M, Ranjbar H. Evaluation of P53 protein expression in gingival tissues of patients with chronic periodontitis by immunohistochemistry methods

OBJECTIVE

Periodontitis is one of the most important periodontal diseases that can be affected by many factors. Although the mechanism of periodontitis development is not yet fully understood, previous studies suggest that apoptosis may be one of the pathological factors that can affect the process of the disease by destroying old and damaged cells. Low expression of P53 protein is one of the reasons for delaying cell death that allows damaged cells to survive longer and gives more time for the chance of mutations and pathogenesis. Because of the important role of P53 in gingival cells of patients with chronic periodontitis, the objective of our study is to evaluate the P53 protein expression in gingival tissues of patients with chronic periodontitis by immunohistochemistry methods.

MATERIALS AND METHODS

In this cross-sectional study, 35 patients with severe to moderate chronic periodontitis (loss of attachment ≥3 mm, probing depth ≥5 mm) with no treatment and 25 people who were healthy for periodontal problems were examined. Gingival biopsies from marginal and attached gingiva were obtained, prepared, and mounted on slides. Then, the expression of P53 on each slide was evaluated by optic microscopy after using P53 antibodies and staining with hematoxylin-eosin (immunohistochemistry method). Data were analyzed using independent t-test, Mann-Whitney U-test, and Spearman correlation test using SPSS Statistics version 18.0.

RESULTS

The mean ages of participants in the case and control groups were 37.58 and 32.09, respectively. Our results showed that the expression of P53 was not significant in periodontitis compared to the control group (p > .05). Also, gender could not affect the expression of P53 in both groups (p > .05), and there was no significant relationship between age and P53 gene incidence.

CONCLUSION

Chronic periodontitis has no significant effect on P53 expression, so changes in apoptosis due to P53 expression in periodontitis are not significant.

MicroRNA sequence and function analysis in peri-implantitis and periodontitis: An animal study

OBJECTIVE

To compare miRNA expression levels and predict relevant target genes and signaling pathways in peri-implantitis and periodontitis.

BACKGROUND

There are many differences between periodontitis and peri-implantitis. An understanding of the similarities and differences in the transcriptional patterns of these diseases, as well as the molecular mechanisms, is beneficial for the development of management strategies.

MATERIALS AND METHODS

Rat models of periodontitis (PD, n = 6) and peri-implantitis (PI, n = 5) were established by ligation. Implantation without ligation (PIC, n = 5) and normal rats (PDC, n = 6) were used as controls. Micro-CT was used to confirm the successful establishment of the model. Gingiva was harvested for miRNA transcriptome sequencing, and the results were confirmed by qRT-PCR. miRNA target genes were predicted with miRTarBase. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed.

RESULTS

Sixty-nine miRNAs were differentially expressed in PI vs. PD, 105 were differentially expressed in PI vs. PIC, and 70 were differentially expressed in PD vs. PDC (log₂ FC ≥1 and padj <0.05). The upregulated genes in all three comparisons were mostly involved in the biological process response to stimulus, whereas most of the downregulated genes were involved in nervous system development (p < .01). The upregulated genes in PI vs. PD and PI vs. PIC were involved in Toll-like receptor signaling and RIG-I-like signaling. The upregulated genes in PI vs. PD were involved in T- and B-cell receptor signaling, apoptosis, and osteoclast differentiation. Focal adhesion was downregulated in all three comparisons, and adherens junction was downregulated in PI vs. PD and PD vs. PDC (p < .1).

CONCLUSION

This study showed differences in the miRNA expression profiles between peri-implantitis and periodontitis and annotated the possible target genes and molecular mechanisms; this study could lay a foundation for the development of management strategies.

The Crossroads of Periodontitis and Oral Squamous Cell Carcinoma: Immune Implications and Tumor Promoting Capacities

Periodontitis (PD) is increasingly considered to interact with and promote a number of inflammatory diseases, including cancer. In the case of oral squamous cell carcinoma (OSCC) the local inflammatory response associated with PD is capable of triggering altered cellular events that can promote cancer cell invasion and proliferation of existing primary oral carcinomas as well as supporting the seeding of metastatic tumor cells into the gingival tissue giving rise to secondary tumors. Both the immune and stromal components of the periodontium exhibit phenotypic alterations and functional differences during PD that result in a microenvironment that favors cancer progression. The inflammatory milieu in PD is ideal for cancer cell seeding, migration, proliferation and immune escape. Understanding the interactions governing this attenuated anti-tumor immune response is vital to unveil unexplored preventive or therapeutic possibilities. Here we review the many commonalities between the oral-inflammatory microenvironment in PD and oral-inflammatory responses that are associated with OSCC progression, and how these conditions can act to promote and sustain the hallmarks of cancer.

Role of cytochrome P450 2C8 genetic polymorphism and epoxygenase uncoupling in periodontal remodelling affecting orthodontic treatment

In genome-wide association studies, the CYP2C8 gene locus has been reported to be associated with bisphosphonate-related osteonecrosis of the jaw, a severe devastating side effect of antiresorptive bone treatment. The aim of this study was to elucidate the putative pathomechanism explaining the association between the genetic polymorphism with the alleles CYP2C8*2 and *3 causing low CYP2C8 activity, and disturbed periodontal remodelling in periodontal fibroblasts cultured from patients undergoing orthodontic treatment. CYP2C8 activity, enzyme expression and substrate metabolism were detected in human periodontal fibroblast cultures. Zoledronic acid caused enhanced reactive oxygen species (ROS) production in periodontal fibroblasts, which was enhanced by arachidonic acid as inflammatory signal. Enhanced bisphosphonate-induced uncoupling of the CYP2C8 enzyme was detected in the variant allele (CYP2C8*3) with the result of increased H₂ O₂ production and lowered substrate oxidation. Conversely, substrate (amodiaquine) addition led to decreased H₂ O₂ production in isolated CYP2C8 enzymes, but in CYP2C8*3 enzyme, increased H₂ O₂ was still detected, especially in presence of arachidonic acid. CYP2C8 variants leading to decreased enzyme activity in substrate oxidation may enhance ROS production by reaction uncoupling, and thus, contribute to difficulties in orthodontic treatment and the risk of side effects of antiresorptive drugs.

Study of the effect of selective inhibitor of Arginase II KUD 975 and of low doses of Acetylsalicylic acid on the functional parameters of the cardiovascular system In experimental preeclampsia

Introduction: Over the past decade, preeclampsia has been the subject of an increased attention, as this complication is the most common cause of maternal mortality, triggering every third case of obstetric morbidity and taking lives of up to 50.000 young women worldwide each year. Despite a large number of ongoing studies, no clear algorithm for monitoring pregnant women with this pathology has been developed yet.

Materials and methods: The study was conducted on 220 female Wistar rats weighing 250–300 g. In the experiment, ADMA-like preeclampsia model was used.

Results and discussion: The introduction of L-NAME to the animals from the 14th till the 20th day of pregnancy causes the following disturbances: a rise in systolic and diastolic blood pressure in 1.4 and 1.5 times, an increase in proteinuria in 3.3 times and an increase in the content of fluid in the greater omentum from 44.39 ± 1.62% to 55.02 ± 1.74%, all of which correspond to the disorders in pregnant women in case of preeclampsia.

The use of the selective inhibitor of arginase II KUD 975 (3mg/kg/day) in combination with acetylsalicylic acid (10mg/kg/day) leads to a pronounced correction in the emerging changes: a decrease in systolic and diastolic blood pressure in 1.2 and 1.3 times, a decrease in proteinuria in 1.9 times and a decrease in the fluid content in the greater omentum.

Conclusion: Selective inhibitor of arginase II KUD 975 and small doses of acetylsalicylic acid have a pronounced positive effect in the correction of morphofunctional disorders in animals with ADMA-like preeclampsia.

Damage-regulated autophagy modulator 1 in oral inflammation and infection

OBJECTIVES

Damage-regulated autophagy modulator (DRAM) 1 is a p53 target gene with possible involvement in oral inflammation and infection. This study sought to examine the presence and regulation of DRAM1 in periodontal diseases.

MATERIAL AND METHODS

In vitro, human periodontal ligament fibroblasts were exposed to interleukin (IL)-1β and Fusobacterium nucleatum for up to 2 days. The DRAM1 synthesis and its regulation were analyzed by real-time PCR, immunocytochemistry, and ELISA. Expressions of other autophagy-associated genes were also studied by real-time PCR. In vivo, synthesis of DRAM1 in gingival biopsies from rats and patients with and without periodontal disease was examined by real-time PCR and immunohistochemistry. For statistics, ANOVA and post-hoc tests were applied (p < 0.05).

RESULTS

In vitro, DRAM1 was significantly upregulated by IL-1β and F. nucleatum over 2 days and a wide range of concentrations. Additionally, increased DRAM1 protein levels in response to both stimulants were observed. Autophagy-associated genes ATG3, BAK1, HDAC6, and IRGM were also upregulated under inflammatory or infectious conditions. In vivo, the DRAM1 gene expression was significantly enhanced in rat gingival biopsies with induced periodontitis as compared to control. Significantly increased DRAM1 levels were also detected in human gingival biopsies from sites of periodontitis as compared to healthy sites.

CONCLUSION

Our data provide novel evidence that DRAM1 is increased under inflammatory and infectious conditions in periodontal cells and tissues, suggesting a pivotal role of DRAM1 in oral inflammation and infection.

CLINICAL RELEVANCE

DRAM1 might be a promising target in future diagnostic and treatment strategies for periodontitis.