MicroRNA-22 suppresses NLRP3/CASP1 inflammasome pathway-mediated proinflammatory cytokine production by targeting the HIF-1α and NLRP3 in human dental pulp fibroblasts.

AIM: To investigate the synergetic regulatory effect of miR-22 on HIF-1α and NLRP3, subsequently regulating the production of the NLRP3/CASP1 inflammasome pathway-mediated proinflammatory cytokines IL-1ß and IL-18 in human dental pulp fibroblasts (HDPFs) during the progression of pulpitis. METHODOLOGY: Fluorescence in situ hybridization (FISH) and immunofluorescence (IF) were performed to determine the localization of miR-22-3p, NLRP3 and HIF-1α in human dental pulp tissues (HDPTs). The miR-22 mimics and inhibitor or plasmid of NLRP3 or HIF-1α were used to upregulate or downregulate miR-22 or NLRP3 or HIF-1α in HDPFs, respectively. Computational prediction via TargetScan 5.1 and a luciferase reporter assay were conducted to confirm target association. The mRNA and protein expression of HIF-1α, NLRP3, caspase-1, IL-1ß and IL-18 were determined by qRT-PCR and western blotting, respectively. The release of IL-1ß and IL-18 was analysed by ELISA. The significance of the differences between the experimental and control groups was determined by one-way analysis of variance, p < .05 indicated statistical significance. RESULTS: A decrease in miR-22 and an increase in HIF-1α and NLRP3 in HDPTs occurred during the transformation of reversible pulpitis into irreversible pulpitis compared with that in the healthy pulp tissues (p < .05). In the normal HDPTs, miR-22-3p was extensively expressed in dental pulp cells. HIF-1α and NLRP3 were mainly expressed in the odontoblasts and vascular endothelial cells. Whereas in the inflamed HDPTs, the odontoblast layers were disrupted. HDPFs were positive for miR-22-3p, HIF-1α and NLRP3. Computational prediction via TargetScan 5.1 and luciferase reporter assays confirmed that both NLRP3 and HIF-1α were direct targets of miR-22 in HDPFs. The miR-22 inhibitor further promoted the activation of NLRP3/CASP1 inflammasome pathway induced by ATP plus LPS and hypoxia (p < .05). In contrast, the miR-22 mimic significantly inhibited the NLRP3/CASP1 inflammasome pathway activation induced by ATP plus LPS and hypoxia (p < .05). CONCLUSION: MiR-22, as a synergetic negative regulator, is involved in controlling the secretion of proinflammatory cytokines mediated by the NLRP3/CASP1 inflammasome pathway by targeting NLRP3 and HIF-1α. These results provide a novel function and mechanism of miR-22-HIF-1α-NLRP3 signalling in the control of proinflammatory cytokine secretion, thus indicating a potential therapeutic strategy for future endodontic treatment.

Activation of the NLRP3/caspase-1 inflammasome in human dental pulp tissue and human dental pulp fibroblasts.

The NLRP3/caspase-1 inflammasome pathway plays an important role in cellular immune defence against bacterial infection; however, its function in human dental pulp tissue and human dental pulp fibroblasts remains poorly understood. We demonstrate that NLRP3 protein expression occurs to a greater extent in pulp tissue with irreversible pulpitis than in normal pulp tissue and in tissue with reversible pulpitis. Caspase-1 is present in its active (cleaved) form only in pulp tissue with irreversible pulpitis. NLRP3 and caspase-1 are expressed in the odontoblast layers in normal human dental pulp tissue, whereas in inflamed pulp tissue, the odontoblast layers are disrupted and dental pulp cells are positive for NLRP3 and caspase-1. Additionally, we investigate the role of the NLRP3/caspase-1 inflammasome pathway in human dental pulp fibroblasts and show that ATP activates the P2X7 receptor on the cell membrane triggering K(+) efflux and inducing the gradual recruitment of the membrane pore pannexin-1. Extracellular lipopolysaccharide is able to penetrate the cytosol and activate NLRP3. Furthermore, the low intracellular K(+) concentration in the cytosol triggers reactive oxygen species generation, which also induces the NLRP3 inflammasome. Thus, the NLRP3/caspase-1 pathway has a biological role in the innate immune response mounted by human dental pulp fibroblasts.

Nemotic human dental pulp fibroblasts promote human dental pulp stem cells migration.

Dental pulp inflammation has long been perceived as a negative factor leading to pulp disruption. Previous studies have suggested that the inflammatory reaction might be a prerequisite for the burst of progenitors implicated in pulp repair. To investigate the migration of human dental pulp stem cells (hDPSCs) in response to human dental pulp fibroblasts (HDPFs) nemosis, an in vitro model of nemosis-induced inflammation in three-dimensional culture was used in this study. We observed HDPF spheroid formation and that cell-cell adhesion between HDPFs leads to necrosis. Cell death detection and cell counting kit-8 assays showed reduced live cell numbers and increased levels of cell membrane leakage in HDPF spheroids. HDPFs spheroids expressed cyclooxygenase-2 and released an increasing amount of prostaglandin E2 and interleukin-8, indicating inflammation in response to nemosis. The Transwell assays showed that the conditioned medium from HDPFs spheroids significantly induced hDPSCs migration more than the medium from the monolayer. Taken together, these results indicate that HDPFs spheroids induce nemosis and contribute to the migration of hDPSCs. This model might provide a potential research tool for studying interactions between fibroblasts and stem cells, and studies concerning nemosis-targeted stem cells might help treat pulp inflammation.

Advancements in Spinal Cord Injury Repair: Insights from Dental-Derived Stem Cells.

Spinal cord injury (SCI), a prevalent and disabling neurological condition, prompts a growing interest in stem cell therapy as a promising avenue for treatment. Dental-derived stem cells, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), stem cells from the apical papilla (SCAP), dental follicle stem cells (DFSCs), are of interest due to their accessibility, minimally invasive extraction, and robust differentiating capabilities. Research indicates their potential to differentiate into neural cells and promote SCI repair in animal models at both tissue and functional levels. This review explores the potential applications of dental-derived stem cells in SCI neural repair, covering stem cell transplantation, conditioned culture medium injection, bioengineered delivery systems, exosomes, extracellular vesicle treatments, and combined therapies. Assessing the clinical effectiveness of dental-derived stem cells in the treatment of SCI, further research is necessary. This includes investigating potential biological mechanisms and conducting Large-animal studies and clinical trials. It is also important to undertake more comprehensive comparisons, optimize the selection of dental-derived stem cell types, and implement a functionalized delivery system. These efforts will enhance the therapeutic potential of dental-derived stem cells for repairing SCI.

Interdisciplinary management of combined periodontal-endodontic lesions with palatogingival grooves of the maxillary lateral incisors: a case report.

A palatogingival groove of the maxillary lateral incisor is an anatomic malformation, which always predisposes the tooth to pulpal and periodontal disease. The diagnosis and treatment planning become complicated, with uncertain prognosis. Herein, we present an effective interdisciplinary management of a case of combined periodontal-endodontic lesions caused by palatogingival grooves. A series of treatment modalities were undertaken to preserve the two teeth, including root canal treatment, periodontal initial therapy, splinting the mobile teeth, occlusal adjustment, apical microsurgery, grinding and sealing grooves, and guided tissue regeneration. An apparent healing of the lesions was visible after 12 months. Therefore, interdisciplinary management of combined periodontal-endodontic lesions with palatogingival grooves of the maxillary lateral incisors is necessary for a favourable long-term outcome.

Ligand-gated ion channel P2X7 regulates NLRP3/Caspase-1-mediated inflammatory pain caused by pulpitis in the trigeminal ganglion and medullary dorsal horn.

Emerging research has revealed that the activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasomes contribute to the development of inflammatory and neuropathic pains. In addition, microglia are involved in the central nervous system (CNS) pain conduction. However, the relationship between NLRP3 inflammasome and dental inflammatory pain conduction is yet to be established. Therefore, this study aimed to investigate the roles of P2X7 and NLRP3/Caspase-1 (CASP1) in the inflammatory pain caused by pulpitis using a rat experimental pulpitis model. We discovered that the decreased pain threshold was inversely correlated with the increased expression of NLRP3, Caspase-1, P2X7, interleukin-1ß (IL-1ß), and IL-18 in the trigeminal ganglion and dorsal horn of the medulla after dental pulp exposure. Furthermore, the pain threshold of rats caused by pulpitis was increased by intraperitoneal injection of Brilliant Blue G (BBG), a P2X7 inhibitor, and the expression levels of NLRP3 and related inflammatory factors IL-1ß and IL-18 were decreased. Moreover, treatment with 130 nM KCl, a P2X7 inhibitor, significantly reduced the expression of NLRP3, IL-1ß, IL-18, Caspase-1, and P2X7 in microglia after lipopolysaccharide(LPS) stimulation. In conclusion, our findings suggest that NLRP3/ CASP1 plays a vital role in the conduction of dental pain; the P2X7regulates NLRP3 pathway in the context of dental inflammatory pain conduction, and inhibiting P2X7 may be a potential strategy for dental inflammatory pain relief.

Multiple Cervical Root Resorption Involving 22 Teeth: A Case with Potential Genetic Predisposition.

A rare case of extensive multiple idiopathic cervical root resorption with potential genetic predisposition was presented. A heathy 19-year-old Chinese male with no contributory medical or family/social history complained of pain during mastication that lasted for several months. Oral examination identified 7 missing teeth and external cervical root resorption involving 9 teeth. Comparison of orthopantomograms taken in May 2021 and February 2022 identified that cervical root resorption occurred in 22 teeth. Resorption commenced at the cementoenamel junction and progressed rapidly over the 9-month period. Laboratory test results were within normal limits. Trio-based whole-exome sequencing showed a missense mutation c.5630 C > T in the filamin A (FLNA) gene at chromosome X of the subject. This is suggestive of the possibility of sex-linked recessive inheritance. This is the first study to report FLNA mutation in human subjects with cervical root resorption involving multiple teeth.

Endodontic management of a fused left maxillary second molar and two paramolars using cone beam computed tomography: A case report.

BACKGROUND: Fused teeth usually involve several complications, such as the development of caries in the groove between fused crowns, tooth impaction, diastemas, aesthetic and periodontal problems, and pulpal pathosis, due to the complex anatomical structure of fused teeth. A thorough diagnosis is paramount to forming an accurate treatment plan and obtaining a favourable prognosis. With the advent of cone-beam computed tomography (CBCT), accurate 3-dimensional images of teeth and their surrounding dentoalveolar structures can now be readily obtained, and the technology can accurately provide a minimally invasive approach to acquire detailed diagnostic information. Therefore, we utilize CBCT data herein to generate a digital model for the infected region in a patient, and this model enables us to better plan the management of his case. CASE SUMMARY: This report details the diagnosis and endodontic treatment of a rare case involving a fused maxillary second molar and two paramolars with apical periodontitis. The patient experienced pain upon biting and cold sensitivity in the area of the maxillary left molar. No caries or other defects were identified in these teeth, and a normal response to a pulp electric viability test was observed. With the aid of CBCT and digital model technology, we initially suspected that the infection originated from the isthmus between the maxillary second molar and two paramolars. Therefore, we only treated the isthmus by an endodontic approach and did not destroy the original tooth structure; furthermore, the vital pulp was retained, and good treatment outcomes were observed at the 24-month follow-up. CONCLUSION: This finding may provide new insights and perspectives on the diagnosis and treatment of fused teeth.

Application of fluoride disturbs plaque microecology and promotes remineralization of enamel initial caries.

Background: The caries-preventive effect of topical fluoride application has been corroborated by a number of clinical studies. However, the effect of fluoride on oral microecology remains unclear. Objective: To monitor the effect of fluoride on dental plaque microecology and demineralization/remineralization balance of enamel initial caries. Methods: Three-year-old children were enrolled and treated with fluoride at baseline and 6 months. International Caries Detection and Assessment System II indices of 52 subjects were measured at baseline, 3, 6, and 12 months. Supragingival plaque samples of 12 subjects were collected at baseline, 3 and 14 days for 16S rRNA sequencing. Results: Changes in microbial community structure were observed at 3 days after fluoridation. Significant changes in the relative abundance of microorganisms were observed after fluoride application, especially Capnocytophaga, unidentified Prevotellaceae and Rothia. Functional prediction revealed that cell movement, carbohydrate and energy metabolism were affected significantly after fluoride application. Fluoride significantly inhibited enamel demineralization and promoted remineralization of early demineralized caries enamel at 3 months. Conclusion: Fluoride application significantly inhibited the progression of enamel initial caries and reversed the demineralization process, possibly by disturbing dental plaque microecology and modulating the physicochemical action of demineralization/remineralization. This deepened our understanding of caries-preventive effects and mechanisms of fluoride.

Nav1.7 via Promotion of ERK in the Trigeminal Ganglion Plays an Important Role in the Induction of Pulpitis Inflammatory Pain.

The trigeminal ganglion (TG) refers to sensory neurons bodies that innervate the spinal cord and peripheral axons that innervate teeth. The tetrodotoxin-sensitive sodium (NA) channels (Nav1.7) play important roles in the pathophysiology of pain. In this study, we investigated the TG expression of Nav1.7 and extracellular signal-regulated kinase (ERK) in a rat model of pulpitis to explore the correlation between these channels and inflammatory pain. Pulpitis was confirmed by hematoxylin-eosin staining. In this study, we demonstrated that the reflex of rats to mechanical stimulation increases after pulp exposure and that the exposed rat molar pulp can upregulate the expression of Nav1.7 and ERK in the rat TG. Three days after rat pulp exposure, the expression levels of the two ion channels in the TG increased. TG target injection of PF04856264, a Nav1.7 inhibitor, dose-dependently increased the mechanical pain threshold and was able to inhibit ERK expression. TG target injection of PD98059, an ERK inhibitor, dose-dependently increased the mechanical pain threshold. These factors simultaneously resulted in the highest production. In this study, with the established link to inflammatory pain, we found that Nav1.7 and ERK both play important roles in the induction of inflammatory pain caused by pulpitis. We also found a correlation between the expression levels of Nav1.7 and ERK and the degree of inflammatory pain. Furthermore, ERK signaling pathways were promoted by the Nav1.7 in TG after pulpitis.

Wnt-GSK3ß/ß-Catenin Regulates the Differentiation of Dental Pulp Stem Cells into Bladder Smooth Muscle Cells.

Smooth muscle cell- (SMC-) based tissue engineering provides a promising therapeutic strategy for SMC-related disorders. It has been demonstrated that human dental pulp stem cells (DPSCs) possess the potential to differentiate into mature bladder SMCs by induction with condition medium (CM) from bladder SMC culture, in combination with the transforming growth factor-ß1 (TGF-ß1). However, the molecular mechanism of SMC differentiation from DPSCs has not been fully uncovered. The canonical Wnt signaling (also known as Wnt/ß-catenin) pathway plays an essential role in stem cell fate decision. The aim of this study is to explore the regulation via GSK3ß and associated downstream effectors for SMC differentiation from DPSCs. We characterized one of our DPSC clones with the best proliferation and differentiation abilities. This stem cell clone has shown the capacity to generate a smooth muscle layer-like phenotype after an extended differentiation duration using the SMC induction protocol we established before. We further found that Wnt-GSK3ß/ß-catenin signaling is involved in the process of SMC differentiation from DPSCs, as well as a serial of growth factors, including TGF-ß1, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), hepatocyte growth factor (HGF), platelet-derived growth factor-homodimer polypeptide of B chain (BB) (PDGF-BB), and vascular endothelial growth factor (VEGF). Pharmacological inhibition on the canonical Wnt-GSK3ß/ß-catenin pathway significantly downregulated GSK3ß phosphorylation and ß-catenin activation, which in consequence reduced the augmented expression of the growth factors (including TGF-ß1, HGF, PDGF-BB, and VEGF) as well as SMC markers (especially myosin) at a late stage of SMC differentiation. These results suggest that the canonical Wnt-GSK3ß/ß-catenin pathway contributes to DPSC differentiation into mature SMCs through the coordination of different growth factors.

Hey1 functions as a positive regulator of odontogenic differentiation in odontoblast­lineage cells.

Substantial evidence has indicated that Notch and bone morphogenetic protein (BMP) signaling may regulate odontoblastic differentiation. Hairy/enhancer­of­split related with YRPW motif 1 (Hey1), a downstream target gene of Notch and BMP signaling, is expressed in dental pulp tissues and has been demonstrated to be responsible for osteoblast mineralization. The aim of this study was to investigate the effects of Hey1 on odontoblast differentiation. The results of the study demonstrated that Hey1 expression in odontoblast­lineage cells (OLCs) was upregulated by stimulation of osteoblastic/odontoblastic differentiation medium containing ascorbic acid, ß­glycerol phosphate and dexamethasone. Furthermore, stable Hey1­overexpressing cells expressed higher levels of dentin sialophosphoprotein (DSPP) and exhibited higher mineralization capabilities following stimulation by differentiation medium. Furthermore, RNA interference­mediated knockdown of Hey1 downregulated the expression levels of DSPP in OLCs stimulated by differentiation medium. Taken together, the findings indicate that Hey1 may be a positive regulator of odontoblastic differentiation. The present study broadens the understanding of odontoblast differentiation and biomineralization.

IFN-γ regulates human dental pulp stem cells behavior via NF-κB and MAPK signaling.

During caries, dental pulp expresses a range of pro-inflammatory cytokines in response to the infectious challenge. Interferon gamma (IFN-γ) is a dimerized soluble cytokine, which is critical for immune responses. Previous study has demonstrated that IFN-γ at relative high concentration (100 ng/mL) treatment improved the impaired dentinogenic and immunosuppressive regulatory functions of disease-derived dental pulp stem cells (DPSCs). However, little is known about the regulatory effects of IFN-γ at relative low concentration on healthy DPSC behavior (including proliferation, migration, and multiple-potential differentiation). Here we demonstrate that IFN-γ at relatively low concentrations (0.5 ng/mL) promoted the proliferation and migration of DPSCs, but abrogated odonto/osteogenic differentiation. Additionally, we identified that NF-κB and MAPK signaling pathways are both involved in the process of IFN-γ-regulated odonto/osteogenic differentiation of DPSCs. DPSCs treated with IFN-γ and supplemented with pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor) or SB203580 (a MAPK inhibitor) showed significantly improved potential for odonto/osteogenic differentiation of DPSCs both in vivo and in vitro. These data provide important insight into the regulatory effects of IFN-γ on the biological behavior of DPSCs and indicate a promising therapeutic strategy for dentin/pulp tissue engineering in future endodontic treatment.

The Regulatory Effects of Long Noncoding RNA-ANCR on Dental Tissue-Derived Stem Cells.

Long noncoding RNAs (lncRNA) have been recognized as important regulators in diverse biological processes, such as transcriptional regulation, stem cell proliferation, and differentiation. Previous study has demonstrated that lncRNA-ANCR (antidifferentiation ncRNA) plays a key role in regulating the proliferation and osteogenic differentiation of periodontal ligament stem cells (PDLSCs). However, little is known about the role of ANCR in regulating other types of dental tissue-derived stem cells (DTSCs) behaviours (including proliferation and multiple-potential of differentiation). In this study, we investigated the regulatory effects of lncRNA-ANCR on the proliferation and differentiation (including osteogenic, adipogenic, and neurogenic differentiation) of DTSCs, including dental pulp stem cells (DPSCs), PDLSCs, and stem cells from the apical papilla (SCAP) by downregulation of lncRNA-ANCR. We found that downregulation of ANCR exerted little effect on proliferation of DPSCs and SCAP but promoted the osteogenic, adipogenic, and neurogenic differentiation of DTSCs. These data provide an insight into the regulatory effects of long noncoding RNA-ANCR on DTSCs and indicate that ANCR is a very important regulatory factor in stem cell differentiation.

Bladder Smooth Muscle Cells Differentiation from Dental Pulp Stem Cells: Future Potential for Bladder Tissue Engineering.

Dental pulp stem cells (DPSCs) are multipotent cells capable of differentiating into multiple cell lines, thus providing an alternative source of cell for tissue engineering. Smooth muscle cell (SMC) regeneration is a crucial step in tissue engineering of the urinary bladder. It is known that DPSCs have the potential to differentiate into a smooth muscle phenotype in vitro with differentiation agents. However, most of these studies are focused on the vascular SMCs. The optimal approaches to induce human DPSCs to differentiate into bladder SMCs are still under investigation. We demonstrate in this study the ability of human DPSCs to differentiate into bladder SMCs in a growth environment containing bladder SMCs-conditioned medium with the addition of the transforming growth factor beta 1 (TGF-ß1). After 14 days of exposure to this medium, the gene and protein expression of SMC-specific marker (α-SMA, desmin, and calponin) increased over time. In particular, myosin was present in differentiated cells after 11 days of induction, which indicated that the cells differentiated into the mature SMCs. These data suggested that human DPSCs could be used as an alternative and less invasive source of stem cells for smooth muscle regeneration, a technology that has applications for bladder tissue engineering.

Mechanisms that lead to the regulation of NLRP3 inflammasome expression and activation in human dental pulp fibroblasts.

BACKGROUND: The NLRP3 inflammasome plays an important role in the cellular defense against invading pathogens and is reported to be expressed in human dental pulp fibroblasts (HDPFs). However, the role of the NLRP3 inflammasome in HDPFs during pulpal infection and inflammation remains unclear. OBJECTIVES: To elucidate the function of the NLRP3 inflammasome and the mechanisms that lead to its expression and activation in HDPFs. METHODS: The test model used lipopolysaccharide (LPS) and adenosine triphosphate (ATP) to simulate an inflammatory environment. Lentiviral vectors encoding short hairpin RNAs were used to knock down NLRP3 and caspase-1 in HDPFs. Specific inhibitors were used to determine whether the toll-like receptor 4 (TLR4), myeloid differentiating factor 88 (MyD88), or nuclear factor-kappa B (NF-κB) pathways were involved in the regulation of NLRP3 expression. Reactive oxygen species (ROS) production was measured by fluorescent microscopy and flow cytometry using the total ROS/superoxide detection kit. Gene and protein expression were quantified by real-time polymerase chain reaction and Western blot, while cytokine release was measured by an enzyme-linked immunosorbent assay. RESULTS: LPS up-regulated NLRP3 and IL-1ß expression while ATP induced the activation of caspase-1 and the release of IL-1ß in LPS-primed HDPFs. The knockdown of NLRP3 or caspase-1 expression significantly inhibited IL-1ß secretion. Pretreatment with a TLR4 inhibitor, a MyD88 inhibitory peptide, or an I Kappa B alpha (IκBα) phosphorylation inhibitor significantly inhibited LPS-induced NLRP3 and IL-1ß expression. ATP potently promoted ROS generation in HDPFs; N-acetyl cysteine inhibited ROS production, caspase-1 activation and IL-1ß secretion induced by ATP. CONCLUSIONS: Our results demonstrated that the NLRP3 inflammasome in HDPFs is crucial for IL-1ß secretion in response to LPS plus ATP. LPS engaged the TLR4/MyD88/NF-κB pathway to enhance NLRP3 and pro-IL-1ß expression in HDPFs. ATP promoted the generation of ROS and activated the NLRP3 inflammasome in a ROS-dependent manner.

Antimicrobial and anti-biofilm effect of Bac8c on major bacteria associated with dental caries and Streptococcus mutans biofilms.

Dental caries is a common oral bacterial infectious disease. Its prevention and treatment requires control of the causative pathogens within dental plaque, especially Streptococcus mutans (S. mutans). Antimicrobial peptides (AMPs), one of the promising substitutes for conventional antibiotics, have been widely tested and used for controlling bacterial infections. The present study focuses on evaluating the potential of the novel AMPs cyclic bactenecin and its derivatives against bacteria associated with dental caries. The results indicate that Bac8c displayed highest activity against the bacteria tested, whereas both cyclic and linear bactenecin had weak antimicrobial activity. The cytotoxicity assay showed that Bac8c did not cause detectable toxicity at concentrations of 32-128µg/ml for 5min or 32-64µg/ml for 60min. S. mutans and Lactobacillus fermenti treated with Bac8c showed variable effects on bacterial structure via scanning electron microscopy and transmission electron microscopy. There appeared to be a large amount of extracellular debris and obvious holes on the cell surface, as well as loss of cell wall and nucleoid condensation. The BioFlux system was employed to generate S. mutans biofilms under a controlled flow, which more closely resemble the formation process of natural biofilms. Bac8c remarkably reduced the viability of cells in biofilms formed in the BioFlux system. This phenomenon was further analyzed and verified by real-time PCR results of a significant suppression of the genes involved in S. mutans biofilm formation. Taken together, this study suggests that Bac8c has a potential clinical application in preventing and treating dental caries.

Whole-genome sequencing of the snub-nosed monkey provides insights into folivory and evolutionary history.

Colobines are a unique group of Old World monkeys that principally eat leaves and seeds rather than fruits and insects. We report the sequencing at 146× coverage, de novo assembly and analyses of the genome of a male golden snub-nosed monkey (Rhinopithecus roxellana) and resequencing at 30× coverage of three related species (Rhinopithecus bieti, Rhinopithecus brelichi and Rhinopithecus strykeri). Comparative analyses showed that Asian colobines have an enhanced ability to derive energy from fatty acids and to degrade xenobiotics. We found evidence for functional evolution in the colobine RNASE1 gene, encoding a key secretory RNase that digests the high concentrations of bacterial RNA derived from symbiotic microflora. Demographic reconstructions indicated that the profile of ancient effective population sizes for R. roxellana more closely resembles that of giant panda rather than its congeners. These findings offer new insights into the dietary adaptations and evolutionary history of colobine primates.

Absent in melanoma 2 (AIM2) in rat dental pulp mediates the inflammatory response during pulpitis.

INTRODUCTION: In recent years, the inflammasome has been determined to play an important role in inflammatory diseases. However, the role of the inflammasome in pulpitis remains unclear. Absent in melanoma 2 (AIM2) is a type of inflammasome that recognizes cytosolic double stranded DNA and forms a caspase-1-activating inflammasome with apoptosis-associated speck-like protein containing a caspase activating recruiting domain. In this study, we determined whether AIM2 was expressed in pulp cells and defined the role of AIM2 in the initiation of inflammation within the dental pulp. METHODS: In the in vivo study, the right maxillary molars from male adult Sprague-Dawley rats (250-350 g) were exposed to the pulp. In the in vitro study, the pulp cells isolated from the mandibular incisors of the Sprague-Dawley rats (2 weeks) were conventionally cultured. Immunofluorescence staining was used to determine the expression and distribution of AIM2 in the rat dental pulp tissues and cells in the presence or absence of inflammatory stimulation. Western blotting and real-time polymerase chain reaction were performed to determine whether there was a correlation between AIM2 expression levels and inflammation both in vivo and in vitro. RESULTS: In healthy dental pulp tissues and cells, AIM2 was only detected in the odontoblast layer. Stimulation significantly increased AIM2 expression in both the dental pulp tissues and cultured cells. The mRNA and protein levels of AIM2 were significantly up-regulated in response to inflammatory stimulation in a dose-dependent manner. Moreover, we also found that AIM2 expression correlated with interleukin-1 levels. These results reveal a direct relationship between the AIM2 inflammasome and pulpitis. CONCLUSIONS: Our study demonstrates that AIM2 is expressed in dental pulp tissues and mediates the inflammatory response during pulpitis. Therapeutic interventions aimed at reducing AIM2 expression may be beneficial in the treatment of pulpitis.

In vitro evaluation of the antibacterial activities of MTAD in combination with nisin against Enterococcus faecalis.

INTRODUCTION: MTAD is a common intracanal irrigant. Although MTAD inhibits Enterococcus faecalis in root canals, its bactericidal effect against E. faecalis remains to be improved. Nisin, an antibacterial peptide, possesses a strong bactericidal effect. The study evaluated the synergetic action between MTAD and nisin against E. faecalis. METHODS: The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were used to measure the antibacterial activities of MTAD, MTAN (substitution of doxycycline with nisin), and MTADN (nisin in combination with doxycycline), respectively. The synergetic effect between nisin and doxycycline was evaluated by fractional inhibitory concentration (FIC) and time-killing curves. Furthermore, morphologic changes in E. faecalis were observed by scanning electron microscopy after E. faecalis was treated with MTAD, MTAN, or MTADN for 24 hours. RESULTS: The MBC of MTADN against E. faecalis was lower than that of MTAD and MTAN. The combination of nisin and doxycycline had a significantly synergetic antibacterial effect on E. faecalis. Among the 3 antimicrobial treatments, MTADN caused the most severe damage to E. faecalis. CONCLUSIONS: The combination of nisin and doxycycline has a synergetic antibacterial effect on E. faecalis, and MTAD in conjunction with nisin inhibits E. faecalis better than MTAD alone.