Characterization of gene expression profile of dental pulp stem cells from human exfoliated deciduous teeth (SHED) in down syndrome

Objectives: Down syndrome is caused by trisomy of chromosome 21 and shows various phenotype in organs. The patients often suffer dental anomalies such as hypodontia and enamel hypoplasia, however, the mechanism of dental anomalies associated to Down syndrome remains unclear. To clarify the details of the dental phenotype of Down syndrome, we performed RNA-sequence (RNA-seq) of dental pulp stem cells from human exfoliated deciduous tooth (SHED). Materials and methods: Three children with Down syndrome were selected as the patient group, and three healthy children were selected as the control group. Dental pulp was collected from extracted teeth during the replacement period between the ages of 5 and 8, and SHED was cultured. RT-qPCR was used to confirm whether there was a difference in the expression level of the gene on chromosome 21. MTT assay and colony formation assay was performed to examine cell proliferation ability. RNA-seq was performed to comprehensively analyze the gene expression difference between control group and Down syndrome group. Results: SHED of control group and Down syndrome group showed no significant difference in cell shape and proliferation activity, while, the expression of COL6A1 was around 1.5-fold change upregulated in Down syndrome group, suggesting that the gene of chromosome 21 became trisomy. RNA-seq analyses revealed that the genes related to organ morphogenesis were upregulated. Furthermore, several genes important for tooth development was raised as significantly upregulated genes. Conclusion: Genetic analysis using SHED was considered a useful tool for elucidating the mechanisms of dental anomalies in Down syndrome.