Cyclin E marks quiescent neural stem cells and caspase-3-positive newborn cells during adult hippocampal neurogenesis in mice

• Published in: Neuroscience letters 2015-10, Vol.607, p.90-96
• Main Authors: Ikeda, Yayoi, Ikeda, Masa-Aki
• Format: Article
• Language: English
• Subjects: Aging - metabolism; Animals; Animals, Newborn; Apoptosis; Biomarkers - metabolism; Caspase 3 - metabolism; Cell Differentiation; Cell Lineage; Cell Nucleus - metabolism; Cell Proliferation; Cyclin E; Cyclin E - metabolism; Dentate gyrus; Embryo, Mammalian; Hippocampus - cytology; Hippocampus - metabolism; Male; Mice, Inbred C57BL; Neural stem cells; Neural Stem Cells - cytology; Neural Stem Cells - metabolism; Neurogenesis; Neuroglia - metabolism; Neurons - cytology; Neurons - metabolism; Postmitotic neurons; Radial glia; Running; Subgranular zone
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2015.09.017

[Display omitted] •Cyclin E is localized to the vertical process of quiescent neural stem cells.•Cyclin E is localized to the nucleus of various stages of neuronal lineage cells.•Cyclin E expression in the dentate gyrus is affected by neurogenic activity.•Cyclin E is co-expressed by active caspase-3-positive neuronal precursor cells.•Cyclin E may play a Cdk-independent role in adult hippocampal neurogenesis. Cyclin E is a key regulator of progression through the G1-phase of the cell cycle. Recently, a cell cycle-independent role for cyclin E in the adult mouse central nervous system has been suggested. In the present study, we examined expression of cyclin E in the mouse hippocampal dentate gyrus (DG), a region of neurogenesis in adulthood, using immunofluorescence. In the adult DG, cyclin E-immunoreactive (cyclin E+) cells was limited to postmitotic cells. In the subgranular zone, cyclin E was detected in the vertical process of radial glia-like cells, which were marked by the neural stem cell markers nestin and GFAP. Cyclin E was also detected in the nucleus of cells, which were labeled with stage-specific neuronal cell markers, including Pax6, Sox2, NeuroD, doublecortin, and NeuN. The densities of cyclin E+ cells in the DG reduced and increased with age and running, respectively. Furthermore, the majority of cyclin E+ cells co-expressed active caspase-3, a marker of apoptosis. Together, the results indicate that cyclin E is expressed in the process of quiescent neural stem cells and in the nucleus of active caspase-3+ cells during neuronal cell differentiation, suggesting that cyclin E has a Cdk-independent function, which might be important for the mechanisms regulating adult hippocampal neurogenesis.