Neurosphere

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

Neural stem cell differentiation is dependent upon endogenous caspase 3 activity

Abstract: Caspase proteases have become the focal point for the development and application of anti-apoptotic therapies in a variety of central nervous system diseases. However, this approach is based on the premise that caspase function is limited to invoking cell death signals. Here, we show that caspase-3 activity is elevated in nonapoptotic differentiating neuronal cell populations. Moreover, peptide inhibition of protease activity effectively inhibits the differentiation process in a cultured neurosphere model. These results implicate caspase-3 activation as a conserved feature of neuronal differentiation and suggest that targeted inhibition of this protease in neural cell populations may have unintended consequences.

Gliogenesis in the central nervous system.

Abstract: Multipotential neuroepithelial stem cells are thought to give rise to all the differentiated cells of the central nervous system (CNS). The developmental potential of these multipotent stem cells becomes more restricted as they differentiate into progressively more committed cells and ultimately into mature neurons and glia. In studying gliogenesis, the optic nerve and spinal cord have become invaluable models and the progressive stages of differentiation are being clarified. Multiple classes of glial precursors termed glial restricted precursors (GRP), oligospheres, oligodendrocyte-type2 astrocyte (O-2A) and astrocyte precursor cells (APC) have been identified. Similar classes of precursor cells can be isolated from human neural stem cell cultures and from embryonic stem (ES) cell cultures providing a non-fetal source of such cells. In this review, we discuss gliogenesis, glial stem cells, putative relationships of these cells to each other, factors implicated in gliogenesis, and therapeutic applications of glial precursors.

Growth and Fate of PSA-NCAM+ Precursors of the Postnatal Brain

Abstract: Oligodendrocyte-type 2 astrocyte (O-2A) lineage cells are derived from multipotential stem cells of the developing CNS. Precursors of O-2A progenitors express the polysialylated (PSA) form of the neural cell adhesion molecule (NCAM) and are detected in neonatal rat brain glial cultures. It is unclear how such PSA-NCAM+ “pre-progenitors” are related to neural stem cells and whether they still have the potential to differentiate along several neural lineages. Here we isolated PSA-NCAM+ pre-progenitor cells from glial cultures by immunopanning and found that most of these cells expressed nestin and PDGF-receptor-α but not O-2A antigens. PSA-NCAM+ cells synthesized transcripts for fibroblast growth factor (FGF) receptors 1, 2, and 3 and responded to FGF2 by survival and proliferation, growing into large clusters resembling neural spheres. FGF2-induced proliferation of PSA-NCAM+ pre-progenitors was significantly enhanced by thyroid hormone (T3), which on its own did not increase cell survival or mitosis. After adhesion and withdrawal of the mitogen, spheres generated mostly oligodendrocytes and astrocytes but very rarely neurons. PSA-NCAM immunopanned cells grown in epidermal growth factor (EGF) also adopted a mostly glial fate after differentiation. In contrast, PSA-NCAM-negative cells and striatal neonatal stem cells, grown in EGF or FGF2, generated the three CNS cell types. Like neural stem cells, PSA-negative cells generated more oligodendrocytes and fewer neurons when expanded in FGF2 and T3. Thus emergence of PSA-NCAM at the surface of neonatal brain precursors coincides with their restriction to a glial fate. T3 modulates these events by enhancing PSA-NCAM+ pre-progenitor growth in FGF2 and favoring an oligodendrocyte fate.

Isolation propagation and directed differentiation of stem cells from embryonic and adult central nervous system of mammals

Abstract: The present invention reveals an in vitro procedure by which a homogeneous population of multipotential precursor cells from mammalian embryonic neuroepithelium (CNS stem cells) can be expanded up to 10 9 fold in culture while maintaining their multipotential capacity to differentiate into neurons, oligodendrocytes, and astrocytes. Chemically defined conditions are presented that enable a large number of neurons, up to 50% of the expanded cells, to be derived from the stem cells. In addition, four factors--PDGF, CNTF, LIF, and T3--have been identified which, individually, generate significantly higher proportions of neurons, astrocytes, or oligodendrocytes. These defined procedures permit a large-scale preparation of the mammalian CNS stem cells, neurons, astrocytes, and oligodendrocytes under chemically defined conditions with efficiency and control. These cells should be an important tool for many cell- and gene-based therapies for neurological disorders.

The RNA-binding protein HuD regulates neuronal cell identity and maturation

Abstract: Neural Hu proteins (HuB/C/D) are RNA-binding proteins that have been shown to induce neuronal differentiation activity when overexpressed in immature neural progenitor cells or undifferentiated neuronal tumors. Newly generated HuD-deficient mice exhibited a transient impaired-cranial-nerve-development phenotype at an early embryonic stage. Adult HuD-deficient mice exhibited an abnormal hind-limb reflex and poor rotarod performance. Analysis of neurosphere formation revealed that the number and self-renewal capacity of the neural stem/progenitor cells were increased in HuD-deficient mice. HuD-deficient primary neurospheres also generated a smaller number of neurons. Cohort analysis of the cellular proliferative activity by using BrdUrd and iododeoxuridine labeling revealed that the number of differentiating quiescent cells in the embryonic cerebral wall was decreased. Long-term administration of BrdUrd revealed that the number of slowly dividing stem cells in the adult subventricular zone was increased in the HuD-deficient mice. Taken together, the results suggest that HuD is required at multiple points during neuronal development, including negative regulation of proliferative activity and neuronal cell-fate acquisition of neural stem/progenitor cells.