Selective regulation of 14-3-3eta in primary culture of cerebral cortical neurons and astrocytes during development.

The 14-3-3 proteins exist predominantly in the brain and may play regulatory roles in cellular processes of growth, differentiation, survival, and apoptosis. The biological functions, however, of the various 14-3-3 isoforms (beta, epsilon, eta, gamma, and zeta) in the brain remain unclear. We have reported previously upregulation of 14-3-3gamma in ischemic astrocytes. In the present study, we report selective regulation of 14-3-3eta in cultured cerebral cortical neurons and astrocytes during in vitro development. In cultured neurons, gene expression levels of 14-3-3eta increase with culture age (0-10 days). Brain-derived neurotrophic factor and neurotrophin-3 upregulate 14-3-3eta gene expression. In cultured astrocytes, 14-3-3eta is downregulated with culture age (1-5 weeks). The gene expression level of 14-3-3eta is not affected by scratch injury in astrocytes or by ischemia in neurons. These data suggest a possible role of 14-3-3eta in growth and differentiation of neurons and astrocytes, indicating an intricate mechanism governing coordinated and well-controlled developmental events in the brain to ensure normal neural functions.