Subventricular zone neuroblasts emigrate toward cortical lesions.

Area of Science:

• Neuroscience
• Cell Biology
• Regenerative Medicine

Background:

• Adult subventricular zone (SVZ) neuroblasts normally migrate to the olfactory bulbs.
• Brain injuries can trigger increased neurogenesis and cell migration from the SVZ to ectopic locations.
• Previous studies indicated glial cell emigration from the SVZ towards cortical injuries.

Purpose of the Study:

• To investigate if cortical injuries increase SVZ neurogenesis.
• To determine if neuroblasts emigrate from the SVZ towards cerebral cortex lesions.
• To examine the role of epidermal growth factor (EGF) in SVZ cell response to injury.

Main Methods:

• Immunohistochemistry using phenotypic markers and BrdU labeling in mice.
• Analysis of doublecortin-positive cells in the SVZ and olfactory bulbs.
• Quantification of epidermal growth factor expression in brain tissues.

Main Results:

• Newborn doublecortin-positive neuroblasts emigrated from the SVZ towards cerebral cortex lesions.
• The number of neuroblasts in the olfactory bulbs remained unchanged, indicating emigration did not impede normal migration.
• SVZ neurogenesis rates did not increase post-injury, despite neuroblast emigration.
• Epidermal growth factor levels were elevated in the SVZ, corpus callosum, and cerebral cortex.

Conclusions:

• Cortical injuries induce emigration of SVZ neuroblasts towards the lesion site.
• This emigration is independent of increased neurogenesis or redirection of migrating cells.
• Epidermal growth factor may act as a key regulator, stimulating SVZ neuroblast emigration following cerebral cortex injury.