FGF8 and BMP2 mediated dynamic regulation of dental mesenchyme proliferation and differentiation via Lhx8/Suv39h1 complex.

The homeobox gene, LIM-homeobox 8 (Lhx8), has previously been identified as an essential transcription factor for dental mesenchymal development. However, how Lhx8 itself is regulated and regulates odontogenesis remains poorly understood. In this study, we employed an RNAscope assay to detect the co-expression pattern of Lhx8 and Suv39h1 in the dental mesenchyme, which coincided with the dynamic expression profiles of the early epithelium signal of Fibroblast Growth Factor 8 (FGF8) and the later mesenchymal signal Bone Morphogenetic Protein 2 (BMP2). Moreover, FGF8 activated Lhx8, whereas BMP2 repressed Lhx8 expression at the transcriptional level. The high expression of Lhx8 in the early dental mesenchyme maintained the cell fate in an undifferentiated status by interacting with Suv39h1, a histone-lysine N-methyltransferase constitutively expressed in the dental mesenchyme. Further in the ex vivo organ culture model, the knockdown of Suv39h1 significantly blocked the function of Lhx8 and FGF8. Mechanistically, Lhx8/Suv39h1 recognized the odontoblast differentiation-related genes and repressed gene expression via methylating H3K9 on their promoters. Taken together, our data here suggest that Lhx8/Suv39h1 complex is inversely regulated by epithelium-mesenchymal signals, balancing the differentiation and proliferation of dental mesenchyme via H3K9 methylation.

Digestive symptoms of COVID-19 and expression of ACE2 in digestive tract organs.

SARS-CoV-2 has resulted in numerous cases of Coronavirus Disease 2019 (COVID-19) worldwide. In addition to fever and respiratory symptoms, digestive symptoms also are observed in some patients with COVID-19. Angiotensin-converting enzyme 2 (ACE2) was reported to be the receptor for SARS-CoV-2. The aim of this study was to comprehensively investigate the digestive symptoms that occur in COVID-19 patients, and the potential pathogenic route of the SARS-CoV-2 infection in digestive tract organs (from the oral cavity to the gastrointestinal tract). We investigated the digestive symptoms of 48 patients with COVID-19 and explored ACE2 expression in digestive tract and lung cancers, based on a series of bulk and single-cell RNA sequencing data obtained from public databases. We found that 25% (12/48) of the patients with COVID-19 suffered from digestive symptoms, among which pharyngalgia (7/48) was the most common manifestation, followed by diarrhea (3/48), anorexia (3/48), and nausea (1/48). The bulk tissue RNA sequencing analysis indicated that digestive tract organs had higher ACE2 expression levels compared to the lung, and the expression of ACE2 in the lung increased with age. Single-cell RNA-Seq results showed that the ACE2-positive-cell ratio in digestive tract organs was significantly higher compared to the lung. ACE2 expression was higher in tumor cells compared to normal control (NC) tissues. While in gastric tissues, ACE2 expression gradually increased from chronic gastritis to metaplasia, to early cancer. Our data might provide a theoretical basis for screening the SARS-CoV-2 susceptible population and for the clinical classification of treatment of patients with COVID-19.

MMP25 Regulates Immune Infiltration Level and Survival Outcome in Head and Neck Cancer Patients.

Background: MMP25 is a critical gene of matrix metalloproteinases (MMPs). However, the molecular mechanism of MMP25 in head and neck cancer pathogenesis remains unclear. Methods: MMP25 expression was analyzed using The Cancer Genome Atlas (TCGA) database, and its influence on clinical prognosis was performed using Kaplan-Meier and Cox regression analyses. The correlation between MMP25 and immune infiltration was investigated by CIBERSORT, TIMER, and ESTIMATE. In addition, the relationship between MMP25 expression and molecular mechanisms was analyzed by gene set enrichment analysis (GSEA), gene ontology (GO), and weighted gene co-expression network analysis (WGCNA). Results: MMP25 expression level correlated with prognosis and immune infiltrating levels, especially activated CD4+ memory T cells, in head and neck cancer. Moreover, MMP25 expression potentially mediated genes, such as IRF8, IKZF1, and DOCK2, and tumor-associated pathways, including p53 signaling, PI3K/AKT/mTOR signaling, and JAK/STAT signaling pathway. Conclusions: These findings suggested that MMP25 plays a critical role in the prognosis and immune infiltration level of head and neck cancer. In addition, MMP25 expression significantly correlated with the regulation of various oncogenes and tumor-related pathways.

Neurosensory dysfunction: A diagnostic marker of early COVID-19.

OBJECTIVE: To describe neurosensory dysfunctions, including hyposmia, hypogeusia, and tinnitus, in patients with COVID-19. METHODS: Clinical characteristics and oropharyngeal swabs were obtained from 86 patients with COVID-19 hospitalized in Guangzhou Eighth People's Hospital. The chronological analysis method was used to detail neurosensory dysfunction. The cycle threshold (Ct) values were used to approximately indicate viral load. RESULTS: Forty-four (51.2%) patients had neurosensory dysfunction: hyposmia (34, 39.5%), hypogeusia (33, 38.4%), and tinnitus (three, 3.5%). Neurosensory dysfunction was significantly more common in patients under 40 years old (p = 0.001) and women (p = 0.006). Hyposmia and hypogeusia coexisted in 23 (26.7%) patients. The interval between onset of hyposmia and hypogeusia was 0.7 ± 1.46 days. The interval from onset of hyposmia and hypogeusia to typical COVID-19 symptoms was 0.22 ± 4.57 and 0.75 ± 6.77 days; the interval from onset of hyposmia and hypogeusia to admission was 6.06 ± 6.68 and 5.76 ± 7.68 days; and the duration of hyposmia and hypogeusia was 9.09 ± 5.74 and 7.12 ± 4.66 days, respectively. The viral load was high following symptoms onset, peaked within the first week, and gradually declined. CONCLUSIONS: Neurosensory dysfunction tends to occur in the early stage of COVID-19, and it could be used as a marker for the early diagnosis of COVID-19.

Necroptosis in head and neck squamous cell carcinoma: characterization of clinicopathological relevance and in vitro cell model.

Necroptosis is a recently discovered form of programmed cell death (PCD) having necrotic-like morphology. However, its presence and potential impact with respect to head and neck squamous cell carcinoma (HNSCC) are still unknown. The aim of this study was to reveal the necroptosis status and its clinicopathological relevance in HNSCC and to establish an in vitro model. We first analyzed the level of p-MLKL, MLKL, and tumor necrosis in HNSCC patient tissues as well as their correlation with clinicopathological features. Results showed that approximately half of the tumor necrosis can be attributed to necroptosis, and the extent of necroptosis is an independent prognostic marker for patient's overall survival and progression-free survival. Then we established and thoroughly verified an in vitro model of necroptosis in two HNSCC cell lines using combined treatment of TNF-α, Smac mimetic and zVAD-fmk (TSZ). At last, we adopted this model and demonstrated that necroptosis can promote migration and invasion of HNSCC cells by releasing damage-associated molecular patterns. In conclusion, our study unveiled the necroptotic status in HNSCC for the first time and provided a novel in vitro model of necroptosis in two HNSCC cell lines. In addition, our results indicated that necroptosis may be a potential cancer promoter in HNSCC. This study may serve as the foundation for future researches of necroptosis in HNSCC.

Effects of Platelet-Rich Plasma on Proliferation, Viability, and Odontogenic Differentiation of Neural Crest Stem-Like Cells Derived from Human Dental Apical Papilla.

OBJECTIVE: This study is aimed at evaluating the effects of platelet-rich plasma (PRP) on proliferation, viability, and odontogenic differentiation of neural crest stem-like cells (NCSCs) derived from human dental apical papilla. MATERIALS AND METHODS: Cells from apical papillae were obtained and then induced to form neural spheres. The expression of NCSC markers p75NTR and HNK-1 in neural sphere cells was detected by immunofluorescence staining. Human PRP was prepared by a 2-step centrifugation method and activated by CaCl2 and thrombin. The concentrations of PDGF-BB and TGF-ß1 in whole blood and PRP were measured by an ELISA kit. PRP in five different concentrations (0%, 2.5%, 5%, 10%, and 25%) was applied to culture NCSCs. On the 1st, 3rd, 5th, and 7th days, cell proliferation was evaluated by CCK8. Cell viability was tested by a live/dead staining kit. mRNA and protein expression of DSPP and BMP4 were analyzed by RT-qPCR and western blot, respectively. Statistical analysis was performed by a one-way analysis of variance (ANOVA) test or t-test. RESULTS: Dental apical papilla cells formed neural spheres, from which cells displayed positive expression of p75NTR and HNK-1. The concentrations of PDGF-BB and TGF-ß1 in PRP were about 3.5-fold higher than those in whole blood. 5% and 10% PRP significantly promoted proliferation of NCSCs, while 25% and 50% PRP inhibited cell proliferation from Day 3 to Day 7. Low-concentration (2.5%, 5%, and 10%) PRP slightly improved viability of NCSCs on Day 7. On the other hand, high-concentration (25% and 50%) PRP significantly inhibited viability of NCSCs from Day 3 to Day 7. RT-qPCR and western blot results indicated that 10% PRP could promote odontogenic differentiation of NCSCs on Day 7. mRNA and protein expression of DSPP and BMP4 were significantly upregulated in the 10% PRP group compared to those in the control group (P < 0.05). CONCLUSIONS: PRP is a simply acquirable blood derivative which contains high concentration of growth factors like PDGF-BB and TGF-ß1. PRP in a proper concentration could promote proliferation, viability, and odontogenic differentiation of NCSCs derived from human dental apical papilla.

CA9 transcriptional expression determines prognosis and tumour grade in tongue squamous cell carcinoma patients.

CA9 is a member of the carbonic anhydrases' family, that is often expressed in cancer cells under hypoxic condition. However, the role of CA9 in the molecular mechanisms of tongue squamous cell carcinoma (TSCC) pathogenesis remains unclear. CA9 expression was analysed using the TCGA database, and its influence on survival was performed using Kaplan-Meier, LASSO and COX regression analyses. The correlation between CA9 and immune infiltration was investigated by CIBERSORT and ESTIMATE. Moreover, the relationship between CA9 expression and downstream molecular regulation pathways was analysed by GSEA, GO and WGCNA. CA9 expression correlated with clinical prognosis and tumour grade in TSCC. Moreover, CA9 expression potentially contributes to the regulation of cancer cell differentiation and mediates tumour-associated genes and signalling pathways, including apoptosis, hypoxia, G2M checkpoint, PI3K/AKR/mTOR signalling and TGF-beta signalling pathways. However, the follicular helper T cells, regulatory T cells, immune and stromal scores showed no significance between high and low CA9 expression groups. These findings suggested that CA9 plays a critical role of TSCC prognosis and tumour grade. CA9 expression significantly correlated with the regulation of cell differentiation, various oncogenes and cancer-associated pathways.

Tooth Regeneration: Insights from Tooth Development and Spatial-Temporal Control of Bioactive Drug Release.

Tooth defect and tooth loss are common clinical diseases in stomatology. Compared with the traditional oral restoration treatment, tooth regeneration has unique advantages and is currently the focus of oral biomedical research. It is known that dozens of cytokines/growth factors and other bioactive factors are expressed in a spatial-temporal pattern during tooth development. On the other hand, the technology for spatial-temporal control of drug release has been intensively studied and well developed recently, making control release of these bioactive factors mimicking spatial-temporal pattern more feasible than ever for the purpose of tooth regeneration. This article reviews the research progress on the tooth development and discusses the future of tooth regeneration in the context of spatial-temporal release of developmental factors.

Optogenetic control of mesenchymal cell fate towards precise bone regeneration.

Rationale: Spatial-temporal control of cell fate in vivo is of great importance for regenerative medicine. Currently, there remain no practical strategies to tune cell-fate spatial-temporally. Optogenetics is a biological technique that widely used to control cell activity in genetically defined neurons in a spatiotemporal-specific manner by light. In this study, optogenetics was repurposed for precise bone tissue regeneration. Methods: Lhx8 and BMP2 genes, which are considered as the master genes for mesenchymal stem cell proliferation and differentiation respectively, were recombined into a customized optogenetic control system. In the system, Lhx8 was constitutively expressed, while BMP2 together with shLhx8 expression was driven by blue light. Results: As expected, blue light induced BMP2 expression and inactivated Lhx8 expression in cells infected with the optogenetic control system. Optogenetic control of BMP2 and Lhx8 expression inversely regulates MSC fate in vitro. By animal study, we found that blue light could fine-tune the regeneration in vivo. Blue light illumination significantly promotes bone regeneration when the scaffold was loaded with MSCs infected with adeno-Lhx8, GI-Gal4DBD, LOV-VP16, and BMP2-shLhx8. Conclusions: Together, our study revealed that optogenetic control of the master genes for mesenchymal stem cell proliferation and differentiation would be such a candidate strategy for precise regenerative medicine.

TGFß induces stemness through non-canonical AKT-FOXO3a axis in oral squamous cell carcinoma.

BACKGROUND: FOXO3a has been widely regarded as a tumor suppressor. It also plays a paradoxical role in regulating the cancer stem cells (CSCs), responsible for tumor-initiation, chemo-resistance, and recurrence in various solid tumors, including oral squamous cell carcinoma (OSCC). This study aims to uncover the role of FOXO3a and its importance for a non-canonical pathway of TGFß in regulating the OSCC stemness. METHODS: We identified FOXO3a expression in OSCC tissues and cell lines using immunohistochemistry and western blot. The correlation between FOXO3a and stemness was evaluated. Stable cell lines with differential expression of FOXO3a were constructed using lentiviruses. The effects of FOXO3a on stem-cell like properties in OSCC was further evaluated in vitro and in vivo. We also explored the effect of TGFß on FOXO3a with respect to its expression and function. FINDINGS: Our findings suggest that FOXO3a was widely expressed and negatively correlated with the stemness in OSCC. This regulation can be abolished by TGFß through phosphorylation, nuclear exclusion, and degradation in the non-Smad pathway. We also observed that non-Smad AKT-FOXO3a axis is essential to regulate stemness of CSCs by TGFß. INTERPRETATION: TGFß induces stemness through non-canonical AKT-FOXO3a axis in OSCC. Our study provides a foundation to understand the mechanism of CSCs and a possible therapeutic target to eliminate CSCs.

MMP-12 regulates proliferation of mouse macrophages via the ERK/P38 MAPK pathways during inflammation.

MMP-12 is a metalloproteinase (MMP) mainly secreted by macrophages and regulating the degradation of the extracellular matrix. MMP-12 is related to several diseases such as emphysema, myocardial infarction and liver fibrosis. However, the functions associated with inflammation of MMP-12 in macrophages have not yet been fully investigated. Therefore, the aim of this study is to elucidate the role of MMP-12 in mouse macrophages during inflammation. Here we show by flow cytometry that MMP-12 was closely associated with the number of F4/80 + macrophages from mouse liver following exposure to LPS. Pro-inflammatory cytokines as well as the proliferation of RAW 264.7 cell line was modulated by MMP-12 knock down as illustrated by qRT-PCR, flow cytometry, CCK-8, Western Blot and EdU staining assays. Furthermore, down-regulation of MMP-12 decreased the expression and the phosphorylation levels of P38 and ERK1/2. Taken together, these data show that MMP-12 contributes to the proliferation of mouse macrophages as well as the secretion of IL-1ß, IL-6, TNF-α, CXCL1 and CXCL3 through the ERK/P38 MAPK signaling pathway.

The role of Foxq1 in proliferation of human dental pulp stem cell.

This study aimed to investigate the role for Foxq1 in proliferation activity regulation of dental pulp stem cells (DPSCs). Proliferation of DPSC was induced by calcium hydroxide, then expression alteration of Foxq1 was evaluated. Lentivirus was employed to manipulate Foxq1 level in DPSC, and proliferation activities were evaluated. To look into mechanism regulating Foxq1 level after calcium hydroxide stimulation, expressions of various microRNAs were evaluated, then bioinformatics study and dual-luciferase study were carried out to confirm targeting relationship between microRNA and Foxq1. The result of our study indicated that proliferation activities of DPSCs were enhanced after calcium hydroxide stimulation, during which expression of Foxq1 was also up-regulated. Cell viability and progression from G1 to S phase were both improved with overexpression of Foxq1, and microRNAs profiling study and dual-luciferase result suggested miR-320b contributed to the up-regulation of Foxq1 after calcium hydroxide stimulation. These results suggested that miR-320b mediated Foxq1 up-regulation promote proliferation of dental pulp stem cells.

Treatment of Necrotic Teeth by Apical Revascularization: Meta-analysis.

Each year ~5.4 million children and adolescents in the United States suffer from dental infections, leading to pulp necrosis, arrested tooth-root development and tooth loss. Apical revascularization, adopted by the American Dental Association for its perceived ability to enable postoperative tooth-root growth, is being accepted worldwide. The objective of the present study is to perform a meta-analysis on apical revascularization. Literature search yielded 22 studies following PRISMA with pre-defined inclusion and exclusion criteria. Intraclass correlation coefficient was calculated to account for inter-examiner variation. Following apical revascularization with 6- to 66-month recalls, root apices remained open in 13.9% cases (types I), whereas apical calcification bridge formed in 47.2% (type II) and apical closure (type III) in 38.9% cases. Tooth-root lengths lacked significant postoperative gain among all subjects (p = 0.3472) or in subgroups. Root-dentin area showed significant increases in type III, but not in types I or II cases. Root apices narrowed significantly in types II and III, but not in type I patients. Thus, apical revascularization facilitates tooth-root development but lacks consistency in promoting root lengthening, widening or apical closure. Post-operative tooth-root development in immature permanent teeth represents a generalized challenge to regenerate diseased pediatric tissues that must grow to avoid organ defects.