Expression of Wnt 3a, β-catenin, cyclin D1 and PCNA in mouse dentate gyrus subgranular zone (SGZ): a possible role of Wnt pathway in SGZ neural stem cell proliferation.

In mammalian dentate gyrus subgranular zone, the addition of new neurons throughout adulthood is a remarkable form of structural plasticity. Yet, the molecular controls over subgranular zone neural stem cell proliferation, survival, and differentiation are poorly understood. In this study we analysed the expression of Wnt 3a, β-catenin, cyclin D1 and proliferating cell nuclear antigen in mouse subgranular zone to elucidate the involvement of Wnt pathway in subgranular zone neural stem cell proliferation. We performed immunohistochemistry and RT-PCR for the above molecules on adult and postnatal developing hippocampal tissues of mice, respectively. RT-PCR analysis showed a gradual increase in expression of mRNA of Wnt 3a, β-catenin, cyclin D1 and proliferating cell nuclear antigen as the postnatal hippocampus developed, and immunohistochemical analysis showed a highly positive immunoreactive expression for Wnt 3a, β-catenin, cyclin D1 and proliferating cell nuclear antigen in the subgranular zone cells. Together, our data suggested that the Wnt pathway is activated in subgranular zone and could play an important role in regulating subgranular zone neural stem cell proliferation in mouse hippocampus.