Dynamic features of postnatal subventricular zone cell motility: a two-photon time-lapse study

Area of Science:

• Neuroscience
• Developmental Biology
• Cell Biology

Background:

• Neuroblasts migrate from the subventricular zone (SVZ) to olfactory bulbs via the rostral migratory stream (RMS).
• Key aspects of SVZ neuroblast migration remain poorly understood, including dynamic visualization of cell chains and migratory behaviors.

Purpose of the Study:

• To dynamically visualize neuroblast migration in the postnatal and adult SVZ and RMS.
• To investigate the morphology, speed, and directionality of migrating neuroblasts.
• To determine if all motile cells in the SVZ express doublecortin (Dcx).

Main Methods:

• Utilized two-photon time-lapse microscopy on brain slices from eGFP transgenic mice.
• Observed neuroblasts expressing doublecortin-eGFP (Dcx-eGFP) and glutamic acid decarboxylase-eGFP (Gad-eGFP).

Main Results:

• Dynamically visualized neuroblast chains (chain migration) maintaining structure for hours despite internal movement.
• Observed shifts in migration direction from rostrocaudal to dorsoventral in different SVZ regions.
• Found that migratory morphology in histologic sections does not predict motility.
• Discovered local, exploratory cell motility in one-third of motile neuroblasts, occurring at slower speeds than long-distance migration.
• Disproved the hypothesis that all motile SVZ cells express Dcx, indicating Dcx is not essential for all SVZ cell migration.

Conclusions:

• SVZ and RMS neuroblast motility is highly complex, involving multiple cell types, behaviors, speeds, and directions.
• Previous assumptions about migratory morphology and Dcx expression in all motile cells are inaccurate.
• This study provides novel insights into the dynamic in situ behavior of migrating neuroblasts.