In Vitro differentiation of conditionally immortalized neuroepithelial stem cells

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In vitro expression of major histocompatibility class I and class II antigens by conditionally immortalized murine neural stem cells

The expression of major histocompatibility complex (MHC) antigens on the surface of cells is intimately linked to in vivo graft survival. It has been previously shown that the conditionally immortalized temperature-sensitive Maudsley hippocampal clone 36 (MHP36) neural stem cells show good long-term graft survival and do not elicit an acute immunological response following transplantation. Here we report that MHP36 cells express both MHC class I and class II antigens when grown in culture under proliferative conditions (33 degrees C), whereas cells with a differentiated morphology in the non-proliferative (37-39 degrees C) condition express low to undetectable levels of either MHC molecules. However, morphologically undifferentiated cells persisting under non-proliferating conditions continued to express both MHC antigens. The downregulation of MHC antigens upon differentiation following cell transplantation could therefore contribute to the graft survival of MHP36 cells

Skit presented by the class of 1894

Skit illustrates a medical school class session

Mapping transplanted stem cell migration after a stroke:a serial, in vivo magnetic resonance imaging study

Preferential migration of stem cells toward the site of a lesion is a highly desirable property of stem cells that allows flexibility in the site of graft implantation in the damaged brain. In rats with unilateral stroke damage, neural stem cells transplanted into the contralateral hemisphere migrate across to the lesioned hemisphere and populate the area around the ischaemic infarct. To date, the migration of neural stem cells in the damaged brain has been mainly inferred from snapshot histological images. In this study, we demonstrate that by pre-labelling neural stem cells with the bimodal contrast agent Gadolinium-RhodamIne Dextran [GRID, detectable by both magnetic resonance imaging (MRI) and fluorescent microscopy], the transhemispheric migration of transplanted neural stem cells contralateral to a stroke lesion can be followed in vivo by serial MRI and corroborated by subsequent histological analyses. Our results indicate that neural stem cells migrated from the injection tract mainly along the corpus callosum within 7 days of transplantation and extensively re-populated the peri-lesion area by 14 days following implantation. In contrast, neural stem cells transplanted into sham controls did not show any substantial migration outside of the injection tract, suggesting that the transcallosal migration observed in the stroke-lesioned animals is due to neural stem cells being attracted by the lesion site. In vivo tracking of the migration of neural stem cells responding to damage will greatly enhance our understanding of optimal transplantation strategies as well as how neural stem cells promote functional and anatomical recovery in neurological disorders