engleski

Stem cell potential in the fetal subplate

Cortical neurons are born in proliferative ventricular zone (VZ) and subventricular zone by mitotic division of stem cells and other progenitors, and subsequently migrate to their final destination forming a transient fetal cortical lamination. Our aim was to identify stem cells, as well as cells with proliferative capacity in subplate (SP) zone during midfetal and late fetal period. Herein, the presence of stem cell potential in the human frontal cortex was studied using proliferative marker Ki67, neural stem cell marker SOX2 and selected cell- specific markers. SOX2 maintains the identity of neural stem cells, therefore serves as one of the critical factors controlling neural differentiation. SOX2 is highly expressed in proliferating neural progenitors cells and is downregulated following differentiation into postmitotic neurons or glial cells. During midfetal period, SOX2-positive cells were found in proliferative zones and scattered throughout the SP. In the VZ and SVZ of the frontal cortex majority of SOX2-positive cells were identified as Ki67-positive, while SOX2 and Ki67 co- localization was found only occasionally in the SP, in addition to uniformly Ki67-positive cells. However, some cells in the SP have only remains of SOX2 reactivity (SOX2+/Ki67-), while sparse SOX2+/Ki67+ reactivity suggests atypically located stem cell. Furthermore, a subset of cells coexpressed SOX2 and GFAP in proliferative zones, but rarely in the SP zone, therefore we cannot implicate if the transitional form of glia in the SP has stem cell potential. Rather, we suggest that remnants of the SOX2+ progenitors move to the SP and reside in yet undefined cell line.

human brain development, transient fetal zones, neural stem cells

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