Neurosphere

About: Neurosphere is a research topic. Over the lifetime, 5145 publications have been published within this topic receiving 321088 citations.

Developmental expression of FMRP in the astrocyte lineage: implications for fragile X syndrome.

Abstract: One of the most common causes of mental retardation in humans, Fragile X syndrome, results from the absence of FMRP, the protein product of the FMR1 gene. In the nervous system, expression of FMRP has been thought to be confined mainly to neurons as little research has examined FMRP expression in non-neuronal lineages. We present evidence that, in addition to neuronal expression, FMRP is expressed in developing CNS glial cells in vitro and in vivo. The neurosphere assay was used to establish cultures of stem and progenitor cells from the brains of wildtype and FMRP knockout (B6.129.FMR1/FvBn) mouse pups. When the neurospheres were differentiated in vitro, approximately 50% of the FMRP positive cells also expressed GFAP. Immunocytochemical studies of the embryonic and postnatal mouse brain revealed coexpression of FMRP and GFAP in the developing hippocampus. Prominent coexpression was also observed in ependymal cells surrounding the third ventricle and astrocytes of the glia limitans. No double-labeled cells were evident in the brains of young adult mice. Cells coexpressing FMRP and the oligodendrocyte precursor marker NG2 were also identified in the hippocampus and corpus callosum of the early postnatal brain. Our results suggest that FMRP is expressed in cells of non-neuronal lineage(s) during development. This represents potential involvement of glial cells in the neural development of fragile X syndrome.

The culture of neural stem cells.

Abstract: A stem cell has three important features. Firstly, the ability of self-renewal: making identical copies of itself. Secondly, multipotency, generating all the major cell lineages of the host tissue (in the case of embryonic stem cells-pluripotency). Thirdly, the ability to generate/regenerate tissues. Thus, the study of stem cells will help unravel the complexity of tissue development and organisation, and will also have important clinical applications. Neural stem cells (NSCs) are present during embryonic development and in certain regions of the adult central nervous system (CNS). Mobilizing adult NSCs to promote repair of injured or diseased CNS is a promising approach. Since NSCs may give rise to brain tumor, they represent in vitro models for anti-cancer drug screening. To facilitate the use of NSCs in clinical scenarios, we need to explore the biology of these cells in greater details. One clear goal is to be able to definitively identify and purify NSCs. The neurosphere-forming assay is robust and reflects the behavior of NSCs. Clonal analysis where single cells give rise to neurospheres need to be used to follow the self-renewal and multipotency characteristics of NSCs. Neurosphere formation in combination with other markers of NSC behavior such as active Notch signaling represents the state of the art to follow these cells. Many issues connected with NSC biology need to be explored to provide a platform for clinical applications. Important future directions that are highlighted in this review are; identification of markers for NSCs, the use of NSCs in high-throughput screens and the modelling of the central nervous development. There is no doubt that the study of NSCs is crucial if we are to tackle the diseases of the CNS such as Parkinson's and Alzheimer's.

Developmental potential of trunk neural crest cells in the mouse.

Abstract: The availability of naturally occurring and engineered mutations in mice which affect the neural crest makes the mouse embryo an important experimental system for studying neural crest cell differentiation. Here, we determine the normal developmental potential of neural crest cells by performing in situ cell lineage analysis in the mouse by microinjecting lysinated rhodamine dextran (LRD) into individual dorsal neural tube cells in the trunk. Labeled progeny derived from single cells were found in the neural tube, dorsal root ganglia, sympathoadrenal derivatives, presumptive Schwann cells and/or pigment cells. Most embryos contained labeled cells both in the neural tube and at least one neural crest derivative, and numerous clones contributed to multiple neural crest derivatives. The time of injection influenced the derivatives populated by the labeled cells. Injections at early stages of migration yielded labeled progeny in both dorsal and ventral neural crest derivatives, whereas those performed at later stages had labeled cells only in more dorsal neural crest derivatives, such as dorsal root ganglion and presumptive pigment cells. The results suggest that in the mouse embryo: (1) there is a common precursor for neural crest and neural tube cells; (2) some neural crest cells are multipotent; and (3) the timing of emigration influences the range of possible neural crest derivatives.