CELLULAR DIFFERENTIATION

点击翻译按钮获取中文摘要

The overall goal of this proposal is to establish how perinatal hypoxia/ischemia (H/I) affects the neural stem cells in the subependymal zone (SZ). The SC cells are actively dividing during the perinatal period to generate neurons and glia. Therefore, insults that destroy or disturb SZ cells will likely disrupt brain development and function. In the last 8 years my collaborators and I have collected a wealth of data on the normal development fates of these stem cells. Based on our extensive characterization, a number of predictions can be made as to how a H/I insult during this critical period of brain development will affect these progenitors. Specific aim 1 will investigate the prediction that H/I will alter the rate or number of proliferating cells in the SC. Specific aim 2 will determine whether H/I kills cells in the SZ. Experiments will be performed to establish the proportion of necrotic versus apoptotic deaths and to reveal the mechanisms responsible for their demise. Since each progenitor has the potential to produce over 100 daughters, the death of even a small number of proliferating stem cells could have a dramatic impact on brain development. Specific aim 3 will establish whether H/I will disrupt the rate or pattern of migration of progenitors from the SZ. A H/I insult will disturb or destroy the radial glial network that immature cells use for migration, and this will likely alter the precise timing or direction of cellular movements that occur during normal brain development. Finally, specific aim 4 will determine whether there is abnormal cell differentiation in the wake of a H/I insult. By altering the micro-environment of the developing brain, perinatal insults also will change the signals that determine cell identify. Our preliminary data indicate that H/I insults impact all of the parameters discussed above. Therefore, completion of these experiments should provide insight into the mechanisms whereby the perinatal hum brain is adversely influence by even mild H/I insults.