ABSTRACT
Abstract Objective This study aims to explore the regulatory mechanism of long noncoding RNA X inactive specific transcript (lncRNA XIST) in the odontogenic differentiation of human dental pulp stem cells (hDPSCs). hDPSCs were obtained from freshly extracted third molars and identified by flow cytometry. Methodology Odontogenic differentiation was induced in mineralized culture medium, and hDPSCs were infected with shRNA lentivirus targeting XIST or fused in sarcoma (FUS), followed by detection of alkaline phoshpatase (ALP) activity, alizarin red staining of mineralized nodules, Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) quantification of XIST expression, and Western blot analysis of FUS, ZBTB16, and odontogenic differentiation markers (DSPP and DMP1). IF-FISH was performed to detect the cellular localization of XIST and FUS. RIP assay validated the XIST and FUS binding. ZBTB16 mRNA stability was tested after actinomycin D treatment. hDPSCs were infected with oe-ZBTB16 lentivirus and further treated with sh-XIST for a combined experiment. Results LncRNA XIST was highly expressed in hDPSCs with odontogenic differentiation. Downregulation of XIST or FUS weakened the ALP activity of hDPSCs, reduced mineralized nodules, diminished DSPP and DMP1 expressions. XIST binds to FUS to stabilize ZBTB16 mRNA and promote ZBTB16 expression. ZBTB16 overexpression partially reversed the inhibitory effect of XIST silencing on odontogenic differentiation of hDPSCs. Conclusion In conclusion, XIST stabilizes ZBTB16 mRNA and promotes ZBTB16 expression by binding to FUS, thereby facilitating the odontogenic differentiation of hDPSCs.
ABSTRACT
Abstract Diabetes is a group of metabolic disorders that can lead to damage and dysfunction of many organs including the dental pulp. Increased inflammatory response, reduction of dentin formation and impaired healing were reported in diabetic dental pulp. Hyperglycemia, which is a main characteristic of diabetes, was suggested to play a role in many diabetic complications. Therefore our aim was to investigate the effects of high glucose levels on proliferation, reactive oxygen species (ROS) production and odontogenic differentiation of human dental pulp cells (HDPCs). HDPCs were cultured under low glucose (5.5mM Glucose), high glucose (25 mM Glucose) and mannitol (iso-osmolar control) conditions. Cell proliferation was analyzed by MTT assay for 11 days. Glutathione and DCFH-DA assay were used to assess ROS and antioxidant levels after 24 h of glucose exposure. Odontogenic differentiation was evaluated and quantified by alizarin red staining on day 21. Expression of mineralization-associated genes, which were alkaline phosphatase, dentin sialophosphoprotein and osteonectin, was determined by RT-qPCR on day 14. The results showed that high glucose concentration decreased proliferation of HDPCs. Odontogenic differentiation, both by gene expression and mineral matrix deposit, was inhibited by high glucose condition. In addition, high DCF levels and low reduced glutathione levels were observed in high glucose condition. However, no differences were observed between mannitol and low glucose conditions. In conclusion, the results clearly showed the negative effect of high glucose condition on HDPCs proliferation and differentiation. Moreover, it also induced ROS production of HDPCs.
Resumo O diabetes abrange um grupo de distúrbios metabólicos que podem levar a danos e disfunções de muitos órgãos, incluindo a polpa dentária. Aumento da resposta inflamatória, redução da formação de dentina e comprometimento da cicatrização foram relatados na polpa dentária diabética. A hiperglicemia, que é uma característica determinante do diabetes, desempenha um papel importante em muitas complicações diabéticas. Portanto, nosso objetivo foi investigar os efeitos dos altos níveis de glicose na proliferação, produção de espécies reativas de oxigênio (ROS, em inglês) e diferenciação odontogênica das células da polpa dental humana (HDPCs, em inglês). As HDPCs foram cultivadas em condições de baixa glicose (glicose 5,5 mM), alta glicose (glicose 25 mM) e manitol (controle iso-osmolar). A proliferação celular foi analisada pelo ensaio MTT por 11 dias. Glutationa e DCFH-DA foram utilizados para avaliar os níveis de ROS e antioxidantes após 24 h de exposição à glicose. A diferenciação odontogênica foi avaliada e quantificada pela coloração com vermelho de alizarina no dia 21. A expressão de genes associados à mineralização, que eram fosfatase alcalina, sialofosfoproteína de dentina e osteonectina, foi determinada por RT-qPCR no dia 14. Os resultados mostraram que a alta concentração de glicose diminuiu a proliferação de HDPCs. A diferenciação odontogênica, tanto pela expressão gênica quanto pelo depósito da matriz mineral, foi inibida pela condição de alta glicose. Além disso, altos níveis de DCF e níveis reduzidos de glutationa foram observados na condição de alta glicose. No entanto, não foram observadas diferenças entre o manitol e as condições de baixa glicose. Em conclusão, os resultados mostraram claramente o efeito negativo da condição de alta glicose na proliferação e diferenciação de HDPCs. Além disso, essa condição também induziu a produção de ROS em HDPCs.