The experimental study on murine cytomegalovirus interferes the differentiation related genes expression of neural stem cells in vitro / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the influence of murine cytomegalovirus ( MCMV) infection on the expression of downstream differentiation related target genes of Wnt signaling pathway in neural stem cells (NSCs) in vitro and explore the molecular mechanism of fetal encephalodysplasia caused by CMV infection. Methods NSCs were separated from fetal BALB/c mouse and cultured in vitro. The NSCs infected by MCMV at a MOI (multiplicity of infection) of 5, 1 and 0.1, respectively, were cultured in differentiation medium. The dynamic expression of the downstream differentiation related target genes ( c-myc, cyclinD1, ngn-1 and ngn-2) of Wnt signal pathway in NSCs were measured by Western blot. Real-time RT-PCR was employed to measure the expression levels of the key differentiation genes ngn-1 in Wnt signal pathway of NSCs post infection. Results The protein levels of c-myc in the infected groups were significantly lower than that in the normal control at 0.5-5 d (P＜0.05) ; At 0. 5 d and 1 d post-infection (p. i. ) , the protein levels of cyclinDl in the infected groups were lower than that in the normal control (P＜0.05). At 2 d and 3 d p. i. , the cyclinD1 expression in the infected groups was higher than that in the control group (P ＜ 0. 05). However, at 4 d and 5 d p. i. , the cyclinD1 levels in the group of the MOI of 5 were lower than in other three groups (F＜0.05). The expression of ngn-1 protein in the infected groups was reduced importantly compared with normal control at 1 -5 d p. i. ( P ＜ 0.05 ). The expression of ngn-1 mRNA in the infected groups was lower than that in the control group at all time points (P ＜ 0. 05 ). The expression of ngn-2 protein decreased at first and then increased, which was opposite to the normal control. The peak of ngn-2 expression in groups of the MOT of 0.1 and 1 occurred later and were significantly lower than that in the normal control (P ＜0. 05). No distinct peak was seen in the group of the MOI of 5. At 1 d p. i. , the expression of ngn-2 of all infected groups was significantly lower than that in the normal control ( P ＜ 0. 05 ). At 2 d p. i. , the expression of in the group of the MOI of 5 was still lower (P ＜ 0.05). While at 3 d, 4 d and 5 d p. i. , the protein levels in all infected groups were higher than that in the normal control (P ＜ 0. 05). The protein expression of these genes increased following the increase of MOI. Conclusion MCMV inhibited the protein expression of c-myc and ngn-1 in differentiated NSCs, repressed the mRNA expression of ngn-1 and caused the perturbed expression of cyclinDl and ngn-2 in a MOI-dependent manner. These data suggest that inhibition of or interference with the protein expression of downstream differentiation related target genes of Wnt signaling pathway in NSCs by MCMV may be one of the important mechanisms, by which proliferation and differentiation of NSCs are inhibited and thus fetal brain is impaired after MCMV infection.