MicroRNA-506 Is Involved in Regulation of the Occurrence of Lipopolysaccharides (LPS)-Induced Pulpitis by Sirtuin 1 (SIRT1)

Elevated mir-141 in obesity: Insights into the interplay with sirtuin 1 and non-alcoholic fatty liver disease

Background

Changes in gene expression related to obesity are linked to microRNAs, such as miR-141, which play a crucial role in metabolic homeostasis. Sirtuin 1 (SIRT1), an enzyme that plays a crucial role in regulating various cellular functions and metabolism, is implicated in obesity and the ensuing non-alcoholic fatty liver disease (NAFLD). The aim of this research was to evaluate the levels of miR-141 and its relationship with SIRT1 and NAFLD.

Methods

A group of 100 adults (50 with obesity and 50 with normal-weight) were selected and underwent complete clinical evaluation and anthropometric measurements. Biochemical parameters were assessed in blood serum, and the levels of miR-141 in plasma were measured by real-time PCR. The expression of the SIRT1 gene was also evaluated in the peripheral blood mononuclear cells using Real-time PCR. The ELISA technique was used to determine insulin levels. Liver steatosis was assessed by ultrasound.

Results

The results showed that levels of miR-141 were significantly increased in participants with obesity compared with the control group. Conversely, the expression of the SIRT1 gene in individuals with obesity was lower than that in control participants. A strong negative correlation was observed between miR-141 and SIRT1 and a strong positive association was observed between miR-141 and metabolic parameters. Furthermore, participants with fatty liver had significantly elevated levels of miR-141 gene expression and lower expression of SIRT1 gene, compared to those without fatty liver.

Conclusion

elevated levels of miR-141 in individuals with obesity might be a contributing factor in the repression of SIRT1 in obesity and its consequences, including NAFLD. Therefore, miR-141 might serve as a suitable diagnostic and therapeutic target in obesity and NAFLD.

Dental pulp stem cells - A basic research and future application in regenerative medicine

Dental pulp is a valuable and accessible source of stem cells (DPSCs) with characteristics similar to mesenchymal stem cells. DPSCs can regenerate a range of tissues and their potential for clinical application in regenerative medicine is promising. DPSCs have been found to express low levels of Class II HLA-DR (MHC) molecules, making them potential candidates for allogeneic transplantation without matching the donor's tissue. Research on the correlation between non-coding RNAs (ncRNAs) and human dental pulp stem cells (DPSCs) provides promising insights into the use of these cells in clinical settings for a wide range of medical conditions. It is possible to use a number of ncRNAs in order to restore the functional role of downregulated ncRNAs that are correlated with osteoblastogenesis, or to suppress the functional role of overexpressed ncRNAs associated with osteoclast differentiation in some cases.

The role of NF-kappaB in the inflammatory processes related to dental caries, pulpitis, apical periodontitis, and periodontitis-a narrative review

Tooth-related inflammatory disorders, including caries, pulpitis, apical periodontitis (AP), and periodontitis (PD), are primarily caused by resident oral microorganisms. Although these dental inflammatory conditions are typically not life-threatening, neglecting them can result in significant complications and greatly reduce an individual's quality of life. Nuclear factor κB (NF-κB), a family formed by various combinations of Rel proteins, is extensively involved in inflammatory diseases and even cancer. This study reviews recent data on NF-κB signaling and its role in dental pulp stem cells (DPSCs), dental pulp fibroblasts (DPFs), odontoblasts, human periodontal ligament cells (hPDLCs), and various experimental animal models. The findings indicate that NF-κB signaling is abnormally activated in caries, pulpitis, AP, and PD, leading to changes in related cellular differentiation. Under specific conditions, NF-κB signaling occasionally interacts with other signaling pathways, affecting inflammation, bone metabolism, and tissue regeneration processes. In summary, data collected over recent years confirm the central role of NF-κB in dental inflammatory diseases, potentially providing new insights for drug development targeting NF-κB signaling pathways in the treatment of these conditions. Keywords: NF-κB, dental caries, pulpitis, apical periodontitis, periodontitis.

Elucidating epigenetic mechanisms governing odontogenic differentiation in dental pulp stem cells: an in-depth exploration

Epigenetics refers to the mechanisms such as DNA methylation and histone modification that influence gene expression without altering the DNA sequence. These epigenetic modifications can regulate gene transcription, splicing, and stability, thereby impacting cell differentiation, development, and disease occurrence. The formation of dentin is intrinsically linked to the odontogenic differentiation of dental pulp stem cells (DPSCs), which are recognized as the optimal cell source for dentin-pulp regeneration due to their varied odontogenic potential, strong proliferative and angiogenic characteristics, and ready accessibility Numerous studies have demonstrated the critical role of epigenetic regulation in DPSCs differentiation into specific cell types. This review thus provides a comprehensive review of the mechanisms by which epigenetic regulation controls the odontogenesis fate of DPSCs.

DUXAP8 Promotes LPS-Induced Cell Injury in Pulpitis by Regulating miR-18b-5p/HIF3A

BACKGROUND

The dysregulated long noncoding RNAs (lncRNAs) are implicated in progression of various diseases, including pulpitis. Double homeobox A pseudogene 8 (DUXAP8) has been found to be upregulated in pulpitis. Herein, the functional mechanism of DUXAP8 in lipopolysaccharide (LPS)-induced pulpitis was explored.

MATERIAL AND METHODS

DUXAP8, microRNA-18b-5p (miR-18b-5p), or hypoxia-inducible factor 3A (HIF3A) levels were examined through reverse transcription-quantitative polymerase chain reaction assay. Cell behaviours were determined by Cell Counting Kit-8 assay for cell viability, Ethynyl-2'-deoxyuridine (EdU) assay for cell proliferation, and flow cytometry for cell apoptosis. Protein levels were measured using western blot. Inflammatory reaction was analysed via enzyme-linked immunosorbent assay. Oxidative stress was assessed by commercial kits. Dual-luciferase reporter assay, RNA immunoprecipitation assay, and pull-down assay were used for validation of interaction between targets.

RESULTS

Cell apoptosis, inflammatory reaction, and oxidative stress were induced by LPS in human dental pulp cells (HDPCs). DUXAP8 upregulation and miR-18b-5p downregulation were found in pulpitis. LPS-induced cell injury was relieved after downregulation of DUXAP8. DUXAP8 interacted with miR-18b-5p. The regulation of DUXAP8 was related to miR-18b-5p sponging function in LPS-treated HDPCs. HIF3A served as a target of miR-18b-5p. MiR-18b-5p protected against LPS-induced cell injury through targeting HIF3A. DUXAP8 targeted miR-18b-5p to regulate HIF3A level.

CONCLUSIONS

Results demonstrated that LPS-induced cell injury in pulpitis was promoted by DUXAP8 through mediating miR-18b-5p/HIF3A axis.

Exploring craniofacial and dental development with microRNAs

microRNAs (miRs) are small RNA molecules that regulate many cellular and developmental processes. They control gene expression pathways during specific developmental time points and are required for tissue homeostasis and stem cell maintenance. miRs as therapeutic reagents in tissue regeneration and repair hold great promise and new technologies are currently being designed to facilitate their expression or inhibition. Due to the large amount of miR research in cells and cancer many cellular processes and gene networks have been delineated however, their in vivo response can be different in complex tissues and organs. Specifically, this report will discuss animal developmental models to understand the role of miRs as well as xenograft, disease, and injury models. We will discuss the role of miRs in clinical studies including their diagnostic function, as well as their potential ability to correct craniofacial diseases.

MicroRNA Modulation during Orthodontic Tooth Movement: A Promising Strategy for Novel Diagnostic and Personalized Therapeutic Interventions

The Orthodontic Tooth Movement (OTM) is allowed through a mediated cell/tissue mechanism performed by applying a force or a pair of forces on the dental elements, and the tooth movement is a fundamental requirement during any orthodontic treatment. In this regard, it has been widely shown that each orthodontic treatment has a minimum duration required concerning numerous factors (age, patient compliance, type of technique used, etc.). In this regard, the aim of the following revision of the literature is to give readers a global vision of principal microRNAs (miRNAs) that are most frequently associated with OTM and their possible roles. Previously published studies of the last 15 years have been considered in the PubMed search using "OTM" and "miRNA" keywords for the present review article. In vitro and in vivo studies and clinical trials were mainly explored. Correlation between OTM and modulation of several miRNAs acting through post-transcriptional regulation on target genes was observed in the majority of previous studied. The expression analysis of miRNAs in biological samples, such as gingival crevicular fluid (GCF), can be considered a useful tool for novel diagnostic and/or prognostic approaches and for new personalized orthodontic treatments able to achieve a better clinical response rate. Although only a few studies have been published, the data obtained until now encourage further investigation of the role of miRNA modulation during orthodontic treatment. The aim of this study is to update the insights into the role and impact of principal micro-RNAs (miRNAs) that are most frequently associated during OTM.

Metabolic Remodeling Impacts the Epigenetic Landscape of Dental Mesenchymal Stem Cells

Epigenetic regulation can dynamically adjust the gene expression program of cell fate decision according to the cellular microenvironment. Emerging studies have shown that metabolic activities provide fundamental components for epigenetic modifications and these metabolic-sensitive epigenetic events dramatically impact the cellular function of stem cells. Dental mesenchymal stem cells are promising adult stem cell resource for in situ injury repair and tissue engineering. In this review, we discuss the impact of metabolic fluctuations on epigenetic modifications in the oral and maxillofacial regions. The principles of the metabolic link to epigenetic modifications and the interaction between metabolite substrates and canonical epigenetic events in dental mesenchymal stem cells are summarized. The coordination between metabolic pathways and epigenetic events plays an important role in cellular progresses including differentiation, inflammatory responses, and aging. The metabolic-epigenetic network is critical for expanding our current understanding of tissue homeostasis and cell fate decision and for guiding potential therapeutic approaches in dental regeneration and infectious diseases.

Specific microRNAs regulate dental pulp stem cell behavior

INTRODUCTION

MicroRNAs (miRNAs), small non-coding RNA, control the translation of messenger RNAs into proteins. miRNAs have a crucial role in regulating the diverse biological processes of many physiological and pathological activities. The aim of this systematic review is to explore various functions of miRNAs in the regulation of dental pulp stem cells (DPSCs) behavior.

METHODS

The articles were searched in PubMed, SCOPUS and ISI Web of Science database using designated keywords. Full-length manuscripts published in English in peer-reviewed journals relevant to the role of miRNAs in DPSC functions were included and reviewed by 2 independent researchers.

RESULTS

The original search of the database generated 299 studies. One hundred and two duplicate studies were removed. After their exclusion, 48 studies were selected for review. miRNAs have shown to modulate the stemness and differentiation of various mesenchymal stem cells. The miRNAs expression profiles in DPSCs were differed compared with other cell types and have been demonstrated to regulate the levels of proteins crucial for promoting or inhibiting DPSC proliferation as well as differentiation. Further, miRNAs also modulate inflammatory processes in dental pulp.

CONCLUSION

miRNAs have various function upon the regulation of DPSCs and understanding these roles of miRNAs is crucial for the development of new therapeutics in regenerative dental medicine. With the advancing technologies, the utilization of miRNA technology could revolutionarily change the future of regenerative endodontics.

Role of Lipopolysaccharide, Derived from Various Bacterial Species, in Pulpitis—A Systematic Review

Lipopolysaccharide (LPS) is widely used for induction of inflammation in various human tissues, including dental pulp. The purpose of this study was to summarize current medical literature focusing on (1) cell types used by researchers to simulate dental pulp inflammation, (2) LPS variants utilized in experimental settings and how these choices affect the findings. Our study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched for studies reporting outcomes of lipopolysaccharide application on dental pulp cells in vitro using electronic databases: MEDLINE, Web of Science and Scopus. Having gathered data from 115 papers, we aimed to present all known effects LPS has on different cell types present in dental pulp. We focused on specific receptors and particles that are involved in molecular pathways. Our review provides an essential foundation for further research using in vitro models of pulpitis.

Epigenetic regulation of dental pulp stem cells and its potential in regenerative endodontics

Regenerative endodontics (RE) therapy means physiologically replacing damaged pulp tissue and regaining functional dentin–pulp complex. Current clinical RE procedures recruit endogenous stem cells from the apical papilla, periodontal tissue, bone marrow and peripheral blood, with or without application of scaffolds and growth factors in the root canal space, resulting in cementum-like and bone-like tissue formation. Without the involvement of dental pulp stem cells (DPSCs), it is unlikely that functional pulp regeneration can be achieved, even though acceptable repair can be acquired. DPSCs, due to their specific odontogenic potential, high proliferation, neurovascular property, and easy accessibility, are considered as the most eligible cell source for dentin–pulp regeneration. The regenerative potential of DPSCs has been demonstrated by recent clinical progress. DPSC transplantation following pulpectomy has successfully reconstructed neurovascularized pulp that simulates the physiological structure of natural pulp. The self-renewal, proliferation, and odontogenic differentiation of DPSCs are under the control of a cascade of transcription factors. Over recent decades, epigenetic modulations implicating histone modifications, DNA methylation, and noncoding (nc)RNAs have manifested as a new layer of gene regulation. These modulations exhibit a profound effect on the cellular activities of DPSCs. In this review, we offer an overview about epigenetic regulation of the fate of DPSCs; in particular, on the proliferation, odontogenic differentiation, angiogenesis, and neurogenesis. We emphasize recent discoveries of epigenetic molecules that can alter DPSC status and promote pulp regeneration through manipulation over epigenetic profiles.

The Role of microRNAs in Pulp Inflammation

The dental pulp can be affected by thermal, physical, chemical, and bacterial phenomena that stimulate the inflammatory response. The pulp tissue produces an immunological, cellular, and vascular reaction in an attempt to defend itself and resolve the affected tissue. The expression of different microRNAs during pulp inflammation has been previously documented. MicroRNAs (miRNAs) are endogenous small molecules involved in the transcription of genes that regulate the immune system and the inflammatory response. They are present in cellular and physiological functions, as well as in the pathogenesis of human diseases, becoming potential biomarkers for diagnosis, prognosis, monitoring, and safety. Previous studies have evidenced the different roles played by miRNAs in proinflammatory, anti-inflammatory, and immunological phenomena in the dental pulp, highlighting specific key functions of pulp pathology. This systematized review aims to provide an understanding of the role of the different microRNAs detected in the pulp and their effects on the expression of the different target genes that are involved during pulp inflammation.

NUTM2A-AS1 silencing alleviates LPS-induced apoptosis and inflammation in dental pulp cells through targeting let-7c-5p/HMGB1 axis

BACKGROUND

Long non-coding RNA (lncRNA) NUTM2A antisense RNA 1 (NUTM2A-AS1) has been reported to be abnormally up-regulated in pulpitis tissues. However, the function of NUTM2A-AS1 in pulpitis remains unclear. The aim of this study was to investigate the role and working mechanism of NUTM2A-AS1 in pulpitis using lipopolysaccharide (LPS)-treated human dental pulp cells (HDPCs).

METHODS

3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry and lactate dehydrogenase (LDH) release detection assay were conducted to analyze the viability of HDPCs. Cell inflammatory response was analyzed through measuring the protein levels of interleukin-6 (IL-6) and IL-8. Western blot assay and quantitative real-time polymerase chain reaction (qRT-PCR) were applied to measure protein expression and RNA expression, respectively. Bioinformatic database StarBase was used to predict the possible targets of NUTM2A-AS1 and let-7c-5p, and dual-luciferase reporter assay was conducted to verify these intermolecular interactions.

RESULTS

LPS stimulation restrained cell viability and induced cell apoptosis and inflammation of HDPCs. LPS exposure up-regulated the expression of NUTM2A-AS1 and High-Mobility Group Box 1 (HMGB1) and down-regulated the level of let-7c-5p. LPS-induced injury in HDPCs was partly attenuated by the silencing of NUTM2A-AS1 or HMGB1. Let-7c-5p was confirmed as a direct target of NUTM2A-AS1, and let-7c-5p bound to the 3' untranslated region (3'UTR) of HMGB1 messenger RNA (mRNA) in HDPCs. HMGB1 overexpression largely overturned NUTM2A-AS1 silencing-mediated effects in LPS-induced HDPCs.

CONCLUSION

NUTM2A-AS1 knockdown attenuated LPS-induced damage in HDPCs partly through targeting let-7c-5p/HMGB1 axis.

MicroRNA-125a-5p modulates macrophage polarization by targeting E26 transformation-specific variant 6 gene during orthodontic tooth movement

OBJECTIVE

The aim of this study was to investigate the role of microRNA-125a-5p (miR-125a-5p) in macrophages during orthodontic tooth movement (OTM).

DESIGN

Periodontal ligament tissues were collected from patients underwent OTM. Periodontal ligament cells were isolated from periodontal ligament tissues. Periodontal ligament stem cells were isolated from normal human impacted third molars. The miR-125-5p levels were measured by real-time quantitative polymerase chain reaction. The impact of miR-125-5p on macrophage polarization was tested by alizarin red staining assay. The effects of miR-125-5p and E26 transformation-specific variant 6 gene (ETV6) on M1/M2 macrophages phenotype markers were determined by real-time quantitative polymerase chain reaction, western blot, and flow cytometry analyses. The interaction between miR-125-5p and ETV6 was verified using luciferase reporter and RNA immunoprecipitation assays.

RESULTS

Periodontal miR-125a-5p was upregulated under the force. Macrophage polarization facilitated osteogenesis by cocultured system. Moreover, miR-125a-5p was upregulated in macrophages polarized with M2 conditions. MiR-125a-5p downregulation promoted the expression of M1 phenotype markers, while suppressed the expression of M2 markers. Mechanistically, ETV6 was confirmed to be a target of miR-125a-5p. ETV6 overexpression increased the expression of M1 polarized markers, while decreased the expression of M2 polarized markers. Furthermore, ETV6 knockdown reversed the effects of miR-125a-5p inhibitor on both M1 macrophages and M2 macrophages.

CONCLUSIONS

Overall, miR-125a-5p facilitates bone healing by targeting ETV6 to promote macrophage M2 polarization.

Effects of epigallocatechin gallate (EGCG) on the biological properties of human dental pulp stem cells and inflammatory pulp tissue

OBJECTIVE

This study aimed to investigate the effect of epigallocatechin gallate (EGCG) on the proliferation, mineralization, inflammation and hypoxia responses of human dental pulp stem cells (hDPSCs) in vitro and its effect on inflammatory pulp tissue in rats in vivo.

DESIGN

The optimum concentration of EGCG was selected by creating a dose response curve. Expression of odontogenic/osteogenic-related genes and inflammatory cytokines after stimulation with Lipopolysaccharide (LPS) was detected by real-time PCR. Under hypoxic conditions, cell proliferation and expression of reactive oxygen species (ROS) and superoxide dismutase (SOD) were detected.In vivo, the maxillary first molars of SD rats were pulpotomized and stimulated with 5 mg/mL LPS for 30 min. Normal saline and EGCG were used to flush the pulp chamber. After 2 months, samples were removed for micro-CT scanning and HE staining.

RESULTS

CCK-8 assay revealed that 10 μg/mL EGCG had no significant effect on the proliferation of hDPSCs. EGCG inhibited expression of IL-1β, IL-6, and TNF-α. Furthermore, EGCG rescued cell proliferation ability, increased SOD activity and reduced ROS expression under hypoxia.In vivo, reduced inflammatory cell accumulation was observed in the coronal pulp in the EGCG group, while in the control group, diffuse inflammatory cells were observed in the radicular pulp.

CONCLUSION

EGCG had no obvious effects on calcified nodule formation but significantly inhibited the inflammatory response of hDPSCs and inhibited apoptosis of hDPSCs caused by hypoxia injury. In vivo, EGCG exerts inhibitory effects on pulp tissue inflammation.

Clinical Value and Potential Target of miR-27a-3p in Pulpitis

INTRODUCTION

This study investigated the clinical values of miR-27a-3p for pulpitis patients, and its association with TLR4.

METHODS

Sixty-six patients with pulpitis and 34 cases without pulpitis were recruited; the pulp tissue and serum samples were collected from each participant. Real-time polymerase chain reaction was used for measurement of gene expression levels. The diagnosis values were assessed by the receiver operating characteristic curve. The target gene of miR-27a-3p was confirmed by the luciferase reporter assay.

RESULTS

MiR-27a-3p was downregulated in both serum and pulp tissue of pulpitis patients. MiR-27a-3p could distinguish pulpitis patients from healthy controls and might be a predictor for the development of irreversible pulpitis. A high level of TLR4 was also detected in both peripheral blood monocytes and pulp tissues from pulpitis patients and showed a negative association with the miR-27a-3p level. TLR4 was a direct target gene of miR-27a-3p.

DISCUSSION/CONCLUSION

MiR-27a-3p might be a promising biomarker for the diagnosis of pulpitis and predict the development of irreversible pulpitis. MiR-27a-3p might be involved in the pathogenesis of pulpitis via targeting TLR4.

Epigenetic Regulation of Dental Pulp Stem Cell Fate

Epigenetic regulation, mainly involving DNA methylation, histone modification, and noncoding RNAs, affects gene expression without modifying the primary DNA sequence and modulates cell fate. Mesenchymal stem cells derived from dental pulp, also called dental pulp stem cells (DPSCs), exhibit multipotent differentiation capacity and can promote various biological processes, including odontogenesis, osteogenesis, angiogenesis, myogenesis, and chondrogenesis. Over the past decades, increased attention has been attracted by the use of DPSCs in the field of regenerative medicine. According to a series of studies, epigenetic regulation is essential for DPSCs to differentiate into specialized cells. In this review, we summarize the mechanisms involved in the epigenetic regulation of the fate of DPSCs.