ABSTRACT
AIM:To explore the relationship and molecular mechanism between microRNA-21(miR-21) and Schwann cells ( SC) following peripheral nerve injury.METHODS: The mRNA expression of miR-21 and phosphatase and tensin homologue deleted on chromosome ten ( PTEN) in animal model were detected by real-time PCR.The over-ex-pression of miR-21 and inhibition of miR-21 expression in the Schwann cells according to transfection of lentiviral vectors were performed, the nonspecific miRNA was used as a negative control ( NC) .The cell apoptosis was measured by flow cy-tometry.The mRNA expression of miR-21 and PTEN in the cells was detected by real-time PCR.The protein expression of PTEN and cleaved caspase-3 was determined by Western blot.RESULTS: The level of miR-21 was significantly higher and the mRNA level of PTEN was significantly lower in the model of nerve injury than those in control group.miR-21 over-expression decreased the number of apoptotic Schwann cells compared with NC-SC.The mRNA expression of PTEN was down-regulated by over-expression of miR-21.The protein expression of PTEN and cleaved caspase-3 was down-regulated by over-expression of miR-21 (P<0.05).CONCLUSION: miR-21 may play an important role in the peripheral nerve injury through inhibiting apoptosis of Schwann cells by down-regulating the expression of PTEN.
ABSTRACT
AIM: To investigate the molecular mechanism of microRNA-21 (miR-21) in the regulation of Schwann cell proliferation following nerve injury.METHODS:The expression of miR-2l was detected by real-time PCR. Synthetic miR-21 mimic and its control were transfected into rat Schwann cells.CCK-8 assay was performed to evaluate the influence of miR-21 on the proliferation of Schwann cells.The cell cycle distribution was determined by flow cytometry. The expression of transforming growth factorβ-induced protein ( TGFBI) and cyclin D1 were detected by Western blotting. RESULTS:The expression of miR-21 in model group was 7.87 ±0.75 and 7.75 ±0.80 times higher than that in sham operation group and blank group respectively.After transfected with miR-21 mimic, the expression of miR-21 in experimen-tal group was 2.21 ±0.14 and 2.29 ±0.21 times higher than that in negative control group and blank group respectively. Moreover, the A450 value of CCK-8 assay in experimental group at 48 h was higher than that in negative control group and blank group.The proliferation index in experimental group was higher than that in negative control group and blank group. At the same time, the expression of TGFBI obviously decreased and the cyclin D1 increased in the Schwann cells 48 h after transfection with miR-21.CONCLUSION:miR-21 promotes the proliferation activity of Schwann cells by down-regulating TGFBI expression.