Transcriptomic analysis of MicroRNA expression in enamel-producing cells

Advances in epidemiological status and pathogenesis of dental fluorosis

Fluoride is commonly consider as a "double-edged sword" because low consumption of fluoride can effectively prevent dental caries, but excessive consumption of fluoride can cause fluorosis. Dental fluorosis (DF) is a characteristic feature of fluorosis in the oral cavity that is manifested as tooth color changes and evident enamel defect. Presently, the pathogenesis of DF remains unclear. Herein, we have summarized the research progress in the pathogenesis and mechanism of DF in the past 5 years.

Altered miRNA expression profiling in enamel organ of fluoride affected rat embryos

Evidence has shown that miRNAs could play a role in dental fluorosis, but there is no study has investigated the global expression miRNA profiles of fluoride-exposed enamel organ. In this study, we analysed the differentially expressed (DE) miRNAs between fluoride-treated and control enamel organ for the first time and found several candidate miRNAs and signaling pathways worthy of further research. Thirty Wistar rats were randomly distributed into three groups and exposed to drinking water with different fluoride contents for 10 weeks and during the gestation. The three groups were a control group (distilled water), medium fluoride group (75 mg/L NaF), and high fluoride group (150 mg/L NaF). On the embryonic day 19.5, the mandible was dissected for histological analysis, and the enamel organ of the mandibular first molar tooth germ was collected for miRNA sequencing (miRNA-seq) and quantitative real-time PCR analysis (qRT-PCR). Typical dental fluorosis was observed in the incisors of the prepregnant rats. In addition to the disorganized structure of enamel organ cells, 39 DE miRNAs were identified in the fluoride groups compared with the control group, and good agreement between the miRNA-seq data and qRT-PCR data was found. The functional annotation of the target genes of 39 DE miRNAs showed significant enrichment in metabolic process, cell differentiation, calcium signaling pathway, and mitogen-activated protein kinase(MAPK) signaling pathway terms. This study provides a theoretical reference for an extensive understanding of the mechanism of fluorosis and potential valuable miRNAs as therapeutic targets in fluorosis.

High throughput sequencing identifies breast cancer-secreted exosomal LncRNAs initiating pulmonary pre-metastatic niche formation

OBJECTIVE

Increasing evidence indicated that cancer-secreted exosomes played an important role in tumor metastasis. However, the function of exosomes in breast cancer pulmonary metastasis remains unknown. The aim of the study was to investigate the role of exosome-derived from breast cancer-secreted long non-coding RNAs (LncRNAs) on pre-metastatic niche formation in pulmonary metastasis.

METHODS

Exosomes-derived from breast cancer were separated by ultracentrifugation. The high-throughput sequencing, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were used to detect and evaluate the differential expression of LncRNAs in lung fibroblasts with exosomes treated. And quantitative real-time polymerase chain reaction (qRT-PCR) was performed to verify candidate LncRNAs expression.

RESULTS

We found that exosomes-derived from breast cancer induced lung fibroblasts proliferation and migration. In addition, a large number of LncRNAs expression abnormalities were involved in the breast cancer lung metastasis microenvironment.

CONCLUSION

Our findings suggested that exosomal LncRNAs facilitated tumor pre-metastatic niche formation and represented a novel mechanistic insight into the molecular mechanism of cancer metastasis microenvironment.