MagT1 regulated the odontogenic differentiation of BMMSCs induced byTGC-CM via ERK signaling pathway.

BACKGROUND: Bone marrow mesenchymal stem cells (BMMSCs) are suitable cell sources for dental pulp regeneration, but the mechanism of BMMSCs differentiation into odontogenic lineage remains unknown. The aim of the present study was to reveal the role of magnesium transporter protein 1 (MagT1) and MAPK pathways in the odontogenic differentiation of BMMSCs. METHODS: The RNA sequencing (RNA-seq) was performed to explore the altered transcriptome of BMMSCs undergoing odontogenic differentiation induced by tooth germ cell-condition medium (TGC-CM). Pathway analysis was conducted to explore enriched pathways of the differential expression signature. Automated western blot, real-time PCR, shRNA lentivirus, and flow cytometry were used to detect the function of MagTl and MAPK pathway in odontogenic differentiation of BMMSCs. RESULTS: RNA-seq identified 622 differentially expressed genes associated with odontogenic differentiation of BMMSCs induced by TGC-CM, some of which were responsible for MAPK pathway. Consistently, we verified that TGC-CM induced odontogenic differentiation of BMMSCs through activating ERK/MAPK pathway, and the inactivation of ERK/MAPK pathway inhibited the odontogenic differentiation induced by TGC-CM. We also found MagT1 protein was significantly increased during odontogenic differentiation of BMMSCs induced by TGC-CMM, in accordance, MagT1 knockdown significantly decreased the extent of mineralized nodules and the protein levels of alkaline phosphatase (ALP), dentin matrix protein 1 (DMP-1), and dentin sialophosphoprotein (DSP). Flow cytometry showed that intracellular Mg2+ was significantly reduced in MagT1-knockdown BMMSCs, indicating the suppression of MagT1 inhibited odontogenic differentiation of BMMSCs by decreasing intracellular Mg2+. Finally, we performed RNA-seq to explore the altered transcriptome of MagT1-knockdown BMMSCs undergoing odontogenic differentiation and identified 281 differentially expressed genes, some of which were involved in MAPK pathway. Consistently, automated western blot analysis found the ERK/MAPK pathway was inhibited in MagT1-knockdown BMMSCs during odontogenic differentiation, indicating that suppression of MagT1 inhibited odontogenic differentiation of BMMSCs via ERK/MAPK pathway. CONCLUSIONS: This study identified the significant alteration of transcriptome in BMMSCs undergoing odontogenic differentiation induced by TGC-CM. We clarified the pivotal role of MagT1 and ERK/MAPK pathway in odontogenic differentiation of BMMSCs, and suppression of MagT1 inhibited the odontogenic differentiation of BMMSCs by decreasing the intracellular Mg2+ and inactivating ERK/MAPK pathway.

Cancer-associated fibroblasts contribute to oral cancer cells proliferation and metastasis via exosome-mediated paracrine miR-34a-5p.

BACKGROUND: Cancer-associated fibroblasts (CAFs) play an important role in regulating tumor progression by transferring exosomes to neighboring cells. Our aim was to clarify the role of microRNA encapsulated in the exosomes derived from CAFs in oral squamous cell carcinoma (OSCC). METHODS: We examined the microRNA expression profiles of exosomes derived from CAFs and donor-matched normal fibroblasts (NFs) from patients with OSCC. We used confocal microscopy to examine the transportation of exosomal miR-34a-5p between CAFs and OSCC cells. Next, luciferase reporter and its mutant plasmids were used to confirm direct target gene of miR-34a-5p. Phenotypic assays and in vivo tumor growth experiments were used to investigate the functional significance of exosomal miR-34a-5p. FINDINGS: We found that the expression of miR-34a-5p in CAF-derived exosomes was significantly reduced, and fibroblasts could transfer exosomal miR-34a-5p to OSCC cells. In xenograft experiments, miR-34a-5p overexpression in CAFs could inhibit the tumorigenesis of OSCC cells. We further revealed that miR-34a-5p binds to its direct downstream target AXL to suppress OSCC cell proliferation and metastasis. Stable ectopic expression of AXL in OSCC cells overexpressing miR-34a-5p restored proliferation and motility abolished by the miRNA. The miR-34a-5p/AXL axis promoted OSCC progression via the AKT/GSK-3ß/ß-catenin signaling pathway, which could induce the epithelial-mesenchymal transition (EMT) to promote cancer cells metastasis. The miR-34a-5p/AXL axis enhanced nuclear translocation of ß-catenin and then induced transcriptional upregulation of SNAIL, which in turn activated both MMP-2 and MMP-9. INTERPRETATION: The miR-34a-5p/AXL axis confers aggressiveness in oral cancer cells through the AKT/GSK-3ß/ß-catenin/Snail signaling cascade and might represent a therapeutic target for OSCC. FUND: National Natural Science Foundation of China.

The relationship between vitamin D receptor gene polymorphism and deciduous tooth decay in Chinese children.

BACKGROUND: In the present study, we explored the link between vitamin D receptor (VDR) BsmI, TaqI, ApaI and FokI gene polymorphisms with deciduous tooth decay in Chinese children. METHODS: Our study included 380 Chinese children aged 4-7 years, whose DNA sample was collected from the buccal mucosa. VDR gene polymorphisms was determined by PCR-RFLP. RESULTS: The adjusted logistic regression analysis demonstrated that BsmI containing the Bb genotype was linked with the increased risk of deciduous tooth decay (OR = 1.856, 95% CI = [1.184, 2.908], p = 0.007). However, VDR polymorphisms ApaI, TaqI and FokI were not associated with deciduous tooth decay (ApaI: OR = 0.839, 95% CI = [0.614, 1.145], p = 0.268; TaqI: OR = 1.150, 95% CI = [0.495, 2.672], p = 0.744; FokI: OR = 0.856, 95% CI = [0.616, 1.191], p = 0.356). CONCLUSIONS: Our results showed that VDR BsmI polymorphism was associated with the risk of deciduous tooth decay in Chinese children aged 4-7 years. However, the specific mechanism remains to further verify through experiment.