Our recent findings indicate an induced upregulation of 14-3-3gamma mRNA and protein in ischemic cortical astrocytes. Despite being brain-specific, the functional role of 14-3-3gamma in the brain still remains largely unknown. In this study, we show that among all the 14-3-3 isoforms, only the gamma isoform is inducible under ischemia in astrocytes. Furthermore, this upregulation of 14-3-3gamma may play a specific protective role in astrocytes under ischemia. Overexpression experiments and antisense treatment show that an elevation of 14-3-3gamma protein in astrocytes promotes survival, while a decrease in 14-3-3gamma enhances apoptosis in astrocytes under ischemia. Under ischemia, endogenous 14-3-3gamma binds p-Bad, thus preventing Bad from entering mitochondria to initiate apoptosis. Therefore, 14-3-3gamma is selectively induced during ischemia to protect astrocytes from apoptosis through p-Bad-related signaling.

Neuroglobin (Ngb), a recently discovered intracellular respiratory globin in neurons, may play a crucial role in oxygen homeostasis in the brain. We report preliminary findings indicating the presence of functional neuroglobin in primary cultures of cerebral cortical astrocytes. Reverse transcription real-time polymerase chain reaction (RRT-PCR) and immunostaining confirmed such presence in cultured astrocytes isolated from newborn mouse brain. Ngb antisense treatment increased apoptosis in ischemic astrocytes. The discovery of Ngb in astrocytes may provide some insight into how oxygen homeostasis is regulated in the brain.

Cell migration is a fundamental phenomenon that underlies tissue morphogenesis, wound healing, immune response, and cancer metastasis. Great progresses have been made in research methodologies, with cell migration identified as a highly orchestrated process. Brain is considered the most complex organ in the human body, containing many types of neural cells with astrocytes playing crucial roles in monitoring normal functions of the central nervous system. Astrocytes are mostly quiescent under normal physiological conditions in the adult brain but become migratory after injury. Under most known pathological conditions in the brain, spinal cord and retina, astrocytes are activated and become hypertrophic, hyperplastic, and up-regulating GFAP based on the grades of severity. These three observations are the hallmark in glia scar formation-astrogliosis. The reactivation process is initiated with structural changes involving cell process migration and ended with cell migration. Detailed mechanisms in astrocyte migration have not been studied extensively and remain largely unknown. Here, we therefore attempt to review the mechanisms in migration of astrocytes.