[Oct4 methylation in induced differentiation of bone mesenchymal stem cells].

OBJECTIVE: To investigate the methylation Oct4 in orientation induced differentiation in bone marrow mesenchymal stem cells METHODS: Mice BMSCs were isolated and purified from bone marrow by adherent culture,and then identified by morphology and immunocytochemistry.Mouse osteoblastic cells were cultured by bone fragments inoculation,and then identified by alkaline phosphatase(AKP)staining and alizarin red staining.BMSCs were induced to differentiate into osteoblasts in vitro. Indirect immunofluorescence staining and reverse transcription polymerase chain reaction(RT PCR)were used to detect the expressions of Oct4 in BMSCs before and after induction.The methylation status of Oct4 gene in mouse BMSCs was explored by a methylation specific PCR before and after induction RESULTS: The isolated mice BMSCs massively proliferated in vitro and formed cell colones with uniform morphology.Positive expressions of CD29,cKit,and CD44 and negative expression of CD34 were found in the isolated cells.After 10 days[DK]'[DK] induction,both AKP and the alizarin red were positive in cells and osteoblastic cells isolated from mice skull bones.The indirect immunoinfluorescence staining and RT-PCR also showed that the Oct4 expression in the directed differentiation of mouse BMSCs was down-regulated.The CpG island of Otc4 gene promoter in mouse BMSCs became methylated during the induced differentiation. CONCLUSIONS: Mice BMSCs and osteoblasts were successfully cultured in vitro in this studyOct4 may be involved in the maintenance of adult stem cell pluripotency.The down regulated expression of Oct4 gene in mouse BMSCs during the directed differentiation may contribute to the methylation of CpG island in Otc4 gene promoter.

[In vitro construction and confirmation of adenovirus containing a mifepristone (RU486)-inducible regulation system for NRF2 gene].

OBJECTIVE: To construct an adenovirus containing a mifepristone (RU486)-inducible regulation system for NRF2 gene, express the product in H460 cell and verify whether the mentioned system can control the gene expression and assess its efficiency. METHODS: A RU486-inducible regulation system for Nrf2 gene was introduced into an adenovirus. The confirmation was performed through the LUC and Dsred genes. And the expression pattern of Nrf2 at the viral level was examined by Western blot and RT-PCR (reverse transcription-polymerase chain reaction). RESULTS: The expressions of LUC and Dsred showed a rising trend with the incremental dose of RU486. After the transfection H460 cell with Ad-RUNrf2, the results of RT-PCR and Western blot demonstrated that the expression of Nrf2 was elevated with a rising dose of RU486. After the removal of RU486, the expression of Nrf2 was reduced. CONCLUSION: The construction of an adenovirus carrying Nrf2 gene regulated by a RU486-inducible system is successful, and RU486 can adjust the cellular expression of Nrf2 factor. The LUC and the Dsred expression assumes the dosage dependence along with RU486 to increase; after the Ad-RUNrf2 infects the H460 cell, through RTPCR and Western the Blot result demonstrated that the expression of Nrf2 increases along with the RU486 dosage increases, after removing RU486, the Nrf2 expression is weaken. Showing the construction of the adenovirus carrying Nrf2 gene regulated by the mifepristone (RU486)-inducible system is successful, and RU486 can adjust the Nrf2 factor in the cell the expression.