Showing papers on "Neurosphere published in 2004"
TL;DR: It is reported that, unlike other brain cancers, the lethal glioblastoma multiforme contains neural precursors endowed with all of the critical features expected from neural stem cells.
Abstract: Transformed stem cells have been isolated from some human cancers. We report that, unlike other brain cancers, the lethal glioblastoma multiforme contains neural precursors endowed with all of the critical features expected from neural stem cells. Similar, yet not identical, to their normal neural stem cell counterpart, these precursors emerge as unipotent (astroglial) in vivo and multipotent (neuronal-astroglial-oligodendroglial) in culture. More importantly, these cells can act as tumor-founding cells down to the clonal level and can establish tumors that closely resemble the main histologic, cytologic, and architectural features of the human disease, even when challenged through serial transplantation. Thus, cells possessing all of the characteristics expected from tumor neural stem cells seem to be involved in the growth and recurrence of adult human glioblastomas multiforme.
2,489 citations
TL;DR: It is shown that endothelial cells but not vascular smooth muscle cells release soluble factors that stimulate the self-renewal of neural stem cells, inhibit their differentiation, and enhance their neuron production.
Abstract: Neural stem cells are reported to lie in a vascular niche, but there is no direct evidence for a functional relationship between the stem cells and blood vessel component cells We show that endothelial cells but not vascular smooth muscle cells release soluble factors that stimulate the self-renewal of neural stem cells, inhibit their differentiation, and enhance their neuron production Both embryonic and adult neural stem cells respond, allowing extensive production of both projection neuron and interneuron types in vitro Endothelial coculture stimulates neuroepithelial cell contact, activating Notch and Hes 1 to promote self-renewal These findings identify endothelial cells as a critical component of the neural stem cell niche
1,531 citations
TL;DR: A ribbon of SVZ astrocytes lining the lateral ventricles of the adult human brain that proliferate in vivo and behave as multipotent progenitor cells in vitro is described.
Abstract: The subventricular zone (SVZ) is a principal source of adult neural stem cells in the rodent brain, generating thousands of olfactory bulb neurons every day. If the adult human brain contains a comparable germinal region, this could have considerable implications for future neuroregenerative therapy. Stem cells have been isolated from the human brain, but the identity, organization and function of adult neural stem cells in the human SVZ are unknown. Here we describe a ribbon of SVZ astrocytes lining the lateral ventricles of the adult human brain that proliferate in vivo and behave as multipotent progenitor cells in vitro. This astrocytic ribbon has not been observed in other vertebrates studied. Unexpectedly, we find no evidence of chains of migrating neuroblasts in the SVZ or in the pathway to the olfactory bulb. Our work identifies SVZ astrocytes as neural stem cells in a niche of unique organization in the adult human brain.
1,285 citations
TL;DR: It is demonstrated that in the absence of serum the combination of basic fibroblast growth factor and platelet-derived growth factor maintains SP cells in the C6 glioma cell line, and proposed that many cancer cell lines contain a minor subpopulation of stem cells that is enriched in an SP, can be maintained indefinitely in culture, and is crucial for their malignancy.
Abstract: Both stem cells and cancer cells are thought to be capable of unlimited proliferation. Paradoxically, however, some cancers seem to contain stem-like cells (cancer stem cells). To help resolve this paradox, we investigated whether established malignant cell lines, which have been maintained for years in culture, contain a subpopulation of stem cells. In this article, we show that many cancer cell lines contain a small side population (SP), which, in many normal tissues, is thought to contain the stem cells of the tissue. We demonstrate that in the absence of serum the combination of basic fibroblast growth factor and platelet-derived growth factor maintains SP cells in the C6 glioma cell line. Moreover, we show that C6 SP cells, but not non-SP cells, can generate both SP and non-SP cells in culture and are largely responsible for the in vivo malignancy of this cell line. Finally, we provide evidence that C6 SP cells can produce both neurons and glial cells in vitro and in vivo. We propose that many cancer cell lines contain a minor subpopulation of stem cells that is enriched in an SP, can be maintained indefinitely in culture, and is crucial for their malignancy.
1,023 citations
TL;DR: These findings identify morphologically distinctive GFAP-expressing progenitor cells as the predominant sources of constitutive adult neurogenesis, and provide new methods for manipulating and investigating these cells.
Abstract: Establishing the cellular identity in vivo of adult multipotent neural progenitors is fundamental to understanding their biology. We used two transgenic strategies to determine the relative contribution of glial fibrillary acidic protein (GFAP)-expressing progenitors to constitutive neurogenesis in the adult forebrain. Transgenically targeted ablation of dividing GFAP-expressing cells in the adult mouse subependymal and subgranular zones stopped the generation of immunohistochemically identified neuroblasts and new neurons in the olfactory bulb and the hippocampal dentate gyrus. Transgenically targeted cell fate mapping showed that essentially all neuroblasts and neurons newly generated in the adult mouse forebrain in vivo, and in adult multipotent neurospheres in vitro, derived from progenitors that expressed GFAP. Constitutively dividing GFAP-expressing progenitors showed predominantly bipolar or unipolar morphologies with significantly fewer processes than non-neurogenic multipolar astrocytes. These findings identify morphologically distinctive GFAP-expressing progenitor cells as the predominant sources of constitutive adult neurogenesis, and provide new methods for manipulating and investigating these cells.
956 citations
TL;DR: In this article, the authors provided ultrastructural evidence showing that highly proliferative precursors in the adult subependymal zone express dopamine receptors and receive dopaminergic afferents.
Abstract: Cerebral dopamine depletion is the hallmark of Parkinson disease. Because dopamine modulates ontogenetic neurogenesis, depletion of dopamine might affect neural precursors in the subependymal zone and subgranular zone of the adult brain. Here we provide ultrastructural evidence showing that highly proliferative precursors in the adult subependymal zone express dopamine receptors and receive dopaminergic afferents. Experimental depletion of dopamine in rodents decreases precursor cell proliferation in both the subependymal zone and the subgranular zone. Proliferation is restored completely by a selective agonist of D2-like (D2L) receptors. Experiments with neural precursors from the adult subependymal zone grown as neurosphere cultures confirm that activation of D2L receptors directly increases the proliferation of these precursors. Consistently, the numbers of proliferating cells in the subependymal zone and neural precursor cells in the subgranular zone and olfactory bulb are reduced in postmortem brains of individuals with Parkinson disease. These observations suggest that the generation of neural precursor cells is impaired in Parkinson disease as a consequence of dopaminergic denervation.
912 citations
TL;DR: It is demonstrated that radial glia cells not only serve as progenitors for many neurons and glial cells soon after birth but also give rise to adult SVZ stem cells that continue to produce neurons throughout adult life.
Abstract: Neural stem cells with the characteristics of astrocytes persist in the subventricular zone (SVZ) of the juvenile and adult brain. These cells generate large numbers of new neurons that migrate through the rostral migratory stream to the olfactory bulb. The developmental origin of adult neural stem cells is not known. Here, we describe a lox-Cre-based technique to specifically and permanently label a restricted population of striatal radial glia in newborn mice. Within the first few days after labeling, these radial glial cells gave rise to neurons, oligodendrocytes, and astrocytes, including astrocytes in the SVZ. Remarkably, the rostral migratory stream contained labeled migratory neuroblasts at all ages examined, including 150-day-old mice. Labeling dividing cells with the S-phase marker BrdUrd showed that new neurons continue to be produced in the adult by precursors ultimately derived from radial glia. Furthermore, both radial glia in neonates and radial glia-derived cells in the adult lateral ventricular wall generated self-renewing, multipotent neurospheres. These results demonstrate that radial glial cells not only serve as progenitors for many neurons and glial cells soon after birth but also give rise to adult SVZ stem cells that continue to produce neurons throughout adult life. This study identifies and provides a method to genetically modify the lineage that links neonatal and adult neural stem cells.
850 citations
TL;DR: The identification of tumor stem cells within adult GBM may represent a major step forward in understanding the origin and maintenance of GBM and lead to the identification and testing of new therapeutic targets.
Abstract: Glioblastoma multiforme (GBM) is the most common adult primary brain tumor and is comprised of a heterogeneous population of cells. It is unclear which cells within the tumor mass are responsible for tumor initiation and maintenance. In this study, we report that brain tumor stem cells can be identified from adult GBMs. These tumor stem cells form neurospheres, possess the capacity for self-renewal, express genes associated with neural stem cells (NSCs), generate daughter cells of different phenotypes from one mother cell, and differentiate into the phenotypically diverse populations of cells similar to those present in the initial GBM. Having a distinguishing feature from normal NSCs, these tumor stem cells can reform spheres even after the induction of differentiation. Furthermore, only these tumor stem cells were able to form tumors and generate both neurons and glial cells after in vivo implantation into nude mice. The identification of tumor stem cells within adult GBM may represent a major step forward in understanding the origin and maintenance of GBM and lead to the identification and testing of new therapeutic targets.
811 citations
TL;DR: It is demonstrated that SOX2 may meet the requirements of a universal neural stem cell marker and provides a means to identify cells which fulfill the basic criteria of a stem cell: self-renewal and multipotent differentiation.
Abstract: Multipotent neural stem cells are present throughout the development of the central nervous system (CNS), persist into adulthood in defined locations and can be derived from more primitive embryonic s
686 citations
TL;DR: The results indicate that GFP‐positive cells in transgenic animals accurately represent neural stem and progenitor cells and suggest that these nestin‐GFP–expressing cells encompass the majority of the neural stem cells in the adult brain.
Abstract: Neural stem cells generate a wide spectrum of cell types in developing and adult nervous systems. These cells are marked by expression of the intermediate filament nestin. We used the regulatory elements of the nestin gene to generate transgenic mice in which neural stem cells of the embryonic and adult brain are marked by the expression of green fluorescent protein (GFP). We used these animals as a reporter line for studying neural stem and progenitor cells in the developing and adult nervous systems. In these nestin-GFP animals, we found that GFP-positive cells reflect the distribution of nestin-positive cells and accurately mark the neurogenic areas of the adult brain. Nestin-GFP cells can be isolated with high purity by using fluorescent-activated cell sorting and can generate multipotential neurospheres. In the adult brain, nestin-GFP cells are approximately 1,400-fold more efficient in generating neurospheres than are GFP-negative cells and, despite their small number, give rise to 70 times more neurospheres than does the GFP-negative population. We characterized the expression of a panel of differentiation markers in GFP-positive cells in the nestin-GFP transgenics and found that these cells can be divided into two groups based on the strength of their GFP signal: GFP-bright cells express glial fibrillary acidic protein (GFAP) but not betaIII-tubulin, whereas GFP-dim cells express betaIII-tubulin but not GFAP. These two classes of cells represent distinct classes of neuronal precursors in the adult mammalian brain, and may reflect different stages of neuronal differentiation. We also found unusual features of nestin-GFP-positive cells in the subgranular cell layer of the dentate gyrus. Together, our results indicate that GFP-positive cells in our transgenic animals accurately represent neural stem and progenitor cells and suggest that these nestin-GFP-expressing cells encompass the majority of the neural stem cells in the adult brain.
667 citations
TL;DR: It is shown that nestin is abundant in ES-derived progenitor cells that have the potential to develop into neuroectodermal, endodermal and mesodermal lineages and suggested that its presence in cells may indicate multi-potentiality and regenerative potential.
Abstract: Tissue-specific progenitor cells are characterized by proliferation and differentiation, but, in contrast to embryonic stem (ES) cells, have limited capacities for self-renewal and no tumourigenic potential. These latter traits make progenitor cells an ideal source for regenerative cell therapies. In this review, we describe what is currently known about nestin, an intermediate filament first identified in neuroepithelial stem cells. During embryogenesis, nestin is expressed in migrating and proliferating cells, whereas in adult tissues, nestin is mainly restricted to areas of regeneration. We show that nestin is abundant in ES-derived progenitor cells that have the potential to develop into neuroectodermal, endodermal and mesodermal lineages. Although it remains unclear what factors regulate in vitro and in vivo expression of nestin, we conclude that nestin represents a characteristic marker of multi-lineage progenitor cells and suggest that its presence in cells may indicate multi-potentiality and regenerative potential.
TL;DR: Transplanted human CNS (hCNS)-derived neurospheres survived robustly in naive and ischemic brains, and the microenvironment influenced their migration and fate.
Abstract: We characterize the survival, migration, and differentiation of human neurospheres derived from CNS stem cells transplanted into the ischemic cortex of rats 7 days after distal middle cerebral artery occlusion. Transplanted neurospheres survived robustly in naive and ischemic brains 4 wk posttransplant. Survival was influenced by proximity of the graft to the stroke lesion and was negatively correlated with the number of IB4-positive inflammatory cells. Targeted migration of the human cells was seen in ischemic animals, with many human cells migrating long distances (≈1.2 mm) predominantly toward the lesion; in naive rats, cells migrated radially from the injection site in smaller number and over shorter distances (0.2 mm). The majority of migrating cells in ischemic rats had a neuronal phenotype. Migrating cells between the graft and the lesion expressed the neuroblast marker doublecortin, whereas human cells at the lesion border expressed the immature neuronal marker β-tubulin, although a small percentage of cells at the lesion border also expressed glial fibrillary acid protein (GFAP). Thus, transplanted human CNS (hCNS)-derived neurospheres survived robustly in naive and ischemic brains, and the microenvironment influenced their migration and fate.
TL;DR: It is reported that in activation of Hes1 and Hes5, known Notch effectors, and additional inactivation of Hes3 extensively accelerate cell differentiation and cause a wide range of defects in brain formation.
Abstract: Radial glial cells derive from neuroepithelial cells, and both cell types
are identified as neural stem cells. Neural stem cells are known to change
their competency over time during development: they initially undergo
self-renewal only and then give rise to neurons first and glial cells later.
Maintenance of neural stem cells until late stages is thus believed to be
essential for generation of cells in correct numbers and diverse types, but
little is known about how the timing of cell differentiation is regulated and
how its deregulation influences brain organogenesis. Here, we report that
inactivation of Hes1 and Hes5 , known Notch effectors, and
additional inactivation of Hes3 extensively accelerate cell
differentiation and cause a wide range of defects in brain formation. In
Hes -deficient embryos, initially formed neuroepithelial cells are not
properly maintained, and radial glial cells are prematurely differentiated
into neurons and depleted without generation of late-born cells. Furthermore,
loss of radial glia disrupts the inner and outer barriers of the neural tube,
disorganizing the histogenesis. In addition, the forebrain lacks the optic
vesicles and the ganglionic eminences. Thus, Hes genes are essential
for generation of brain structures of appropriate size, shape and cell
arrangement by controlling the timing of cell differentiation. Our data also
indicate that embryonic neural stem cells change their characters over time in
the following order: Hes -independent neuroepithelial cells,
transitory Hes -dependent neuroepithelial cells and
Hes -dependent radial glial cells.
TL;DR: The reduction in the neural stem cell population documented here is sufficient to account for the reduced level of neurogenesis in old animals and comparison of the NSC populations in the subventricular zones of young and old mice demonstrates an approximately twofold reduction.
Abstract: The mammalian brain contains neural stem cells (NSCs) that allow continued neurogenesis throughout the life of the animal. However, neurogenesis is known to decline during aging and, to the extent that neurogenesis is required for normal CNS function, this may contribute to neurodegenerative disease. Decreased neurogenesis could result from loss of NSCs or dysfunction at some later step, and distinguishing these possibilities is important for understanding the cause of the decline. However, because of the inability to distinguish NSCs from their rapidly dividing progeny in situ, it has not been possible to quantitatively assess the NSC populations in young and old animals. In this report we show that the G1 phase-specific expression of the replication factor Mcm2 is a useful marker for detecting slowly cycling putative NSCs in situ and confirm the identity of these cells using both cytosine β-d-arabinofuranoside (Ara-C) treatment and a double nucleoside analog-labeling technique. The ability to distinguish NSCs from proliferative progenitors has allowed characterization of the expression of several markers including Nestin, Musashi, and GFAP in these different cell types. Furthermore, comparison of the NSC populations in the subventricular zones of young (2-4 months) and old (24-26 months) mice demonstrates an approximately twofold reduction in the older mice. A similar twofold reduction is also observed in the number of neurospheres recovered in culture from old relative to young animals. The reduction in the neural stem cell population documented here is sufficient to account for the reduced level of neurogenesis in old animals.
TL;DR: The efficient conversion of human adult bone marrow stromal cells (hMSC) into a neural stem cell-like population (hmNSC, for human marrow-derived NSC-like cells) is described and it is demonstrated that individual hmNSCs are multipotent and retain the capacity to generate both glia and neurons.
Abstract: Clonogenic neural stem cells (NSCs) are self-renewing cells that maintain the capacity to differentiate into brain-specific cell types, and may also replace or repair diseased brain tissue NSCs can be directly isolated from fetal or adult nervous tissue, or derived from embryonic stem cells Here, we describe the efficient conversion of human adult bone marrow stromal cells (hMSC) into a neural stem cell-like population (hmNSC, for human marrow-derived NSC-like cells) These cells grow in neurosphere-like structures, express high levels of early neuroectodermal markers, such as the proneural genes NeuroD1, Neurog2, MSl1 as well as otx1 and nestin, but lose the characteristics of mesodermal stromal cells In the presence of selected growth factors, hmNSCs can be differentiated into the three main neural phenotypes: astroglia, oligodendroglia and neurons Clonal analysis demonstrates that individual hmNSCs are multipotent and retain the capacity to generate both glia and neurons Our cell culture system provides a powerful tool for investigating the molecular mechanisms of neural differentiation in adult human NSCs hmNSCs may therefore ultimately help to treat acute and chronic neurodegenerative diseases
TL;DR: The isolation of human embryonic stem (hES) cells introduced a new prospect for obtaining a sufficient number of β cells for transplantation for type I diabetes mellitus.
Abstract: Type I diabetes mellitus is caused by an autoimmune destruction of the insulin-producing beta cells. The major obstacle in using transplantation for curing the disease is the limited source of insulin-producing cells. The isolation of human embryonic stem (hES) cells introduced a new prospect for obtaining a sufficient number of beta cells for transplantation. We present here a method for forming immature islet-like clusters of insulin-producing cells derived from hES cells. The protocol consisted of several steps. Embryoid bodies were first cultured and plated in insulin-transferrin-selenium-fibronectin medium, followed by medium supplemented with N2, B27, and basic fibroblast growth factor (bFGF). Next, the glucose concentration in the medium was lowered, bFGF was withdrawn, and nicotinamide was added. Dissociating the cells and growing them in suspension resulted in the formation of clusters which exhibited higher insulin secretion and had longer durability than cells grown as monolayers. Reverse transcription-polymerase chain reaction detected an enhanced expression of pancreatic genes in the differentiated cells. Immunofluorescence and in situ hybridization analyses revealed a high percentage of insulin-expressing cells in the clusters. In addition to insulin, most cells also coexpressed glucagon or somatostatin, indicating a similarity to immature pancreatic cells. Further improvement of this insulin-producing cell protocol may lead to the formation of an unlimited source of cells suitable for transplantation.
TL;DR: The data show that the adult mouse whisker follicle contains pluripotent neural crest stem cells, termed epidermal neural crest cells (eNCSC), which are promising candidates for diverse cell therapy paradigms because of their high degree of inherent plasticity and due to their easy accessibility in the skin.
Abstract: We report the presence of pluripotent neural crest stem cells in the adult mammalian hair follicle. Numerous neural crest cells reside in the outer root sheath from the bulge to the matrix at the base of the follicle. Bulge explants from adult mouse whisker follicles yield migratory neural crest cells, which in clonal culture form colonies consisting of over a thousand cells. Clones contain neurons, smooth muscle cells, rare Schwann cells and melanocytes, demonstrating pluripotency of the clone-forming cell. Targeted differentiation into Schwann cells and chondrocytes was achieved with neuregulin-1 and bone morphogenetic protein-2, respectively. Serial cloning in vitro demonstrated self-renewal capability. Together, the data show that the adult mouse whisker follicle contains pluripotent neural crest stem cells, termed epidermal neural crest cells (eNCSC). eNCSC are promising candidates for diverse cell therapy paradigms because of their high degree of inherent plasticity and due to their easy accessibility in the skin.
TL;DR: Findings indicate that in the adult stroke brain, increases in recruitment of neural stem cells contribute to stroke-induced neurogenesis, and that newly generated neurons migrate from the SVZ to the ischemic striatum.
Abstract: Stroke increases neurogenesis. The authors investigated whether neural stem cells or progenitor cells in the adult subventricular zone (SVZ) of rats contribute to stroke-induced increase in neurogenesis. After induction of stroke in rats, the numbers of cells immunoreactive to doublecortin, a marker for immature neurons, increased in the ipsilateral SVZ and striatum. Infusion of an antimitotic agent (cytosine-beta-D-arabiofuranoside, Ara-C) onto the ipsilateral cortex eliminated more than 98% of actively proliferating cells in the SVZ and doublecortin-positive cells in the ipsilateral striatum. However, doublecortin-positive cells rapidly replenished after antimitotic agent depletion of actively proliferating cells. Depleting the numbers of actively proliferating cells in vivo had no effect on the numbers of neurospheres formed in vitro, yet the numbers of neurospheres derived from stroke rats significantly (P<0.05) increased. Neurospheres derived from stroke rats self-renewed and differentiated into neurons and glia. In addition, doublecortin-positive cells generated in the SVZ migrated in a chainlike structure toward ischemic striatum. These findings indicate that in the adult stroke brain, increases in recruitment of neural stem cells contribute to stroke-induced neurogenesis, and that newly generated neurons migrate from the SVZ to the ischemic striatum.
TL;DR: It is shown that the subventricular zone (SVZ) of the lateral ventricle, the largest neurogenic area of the adult brain, is a major sAPP binding site and that binding occurs on progenitor cells expressing the EGF receptor.
Abstract: The amyloid precursor protein (APP) is a type I transmembrane protein of unknown physiological function. Its soluble secreted form (sAPP) shows similarities with growth factors and increases the in vitro proliferation of embryonic neural stem cells. As neurogenesis is an ongoing process in the adult mammalian brain, we have investigated a role for sAPP in adult neurogenesis. We show that the subventricular zone (SVZ) of the lateral ventricle, the largest neurogenic area of the adult brain, is a major sAPP binding site and that binding occurs on progenitor cells expressing the EGF receptor. These EGF-responsive cells can be cultured as neurospheres (NS). In vitro, EGF provokes soluble APP (sAPP) secretion by NS and anti-APP antibodies antagonize the EGF-induced NS proliferation. In vivo, sAPP infusions increase the number of EGF-responsive progenitors through their increased proliferation. Conversely, blocking sAPP secretion or downregulating APP synthesis decreases the proliferation of EGF-responsive cells, which leads to a reduction of the pool of progenitors. These results reveal a new function for sAPP as a regulator of SVZ progenitor proliferation in the adult central nervous system.
TL;DR: A new perspective on BM not only as a home for hematopoietic stem cells but also a ‘hideout’ for already differentiated CXCR4-positive tissue-committed stem/progenitor cells that follow an SDF-1 gradient, could be mobilized into PB, and subsequently take part in organ/tissue regeneration.
Abstract: It has been suggested that bone marrow (BM)-derived hematopoietic stem cells transdifferentiate into tissue-specific stem cells (the so-called phenomenon of stem cell plasticity), but the possibility of committed tissue-specific stem cells pre-existing in BM has not been given sufficient consideration. We hypothesized that (i) tissue-committed stem cells circulate at a low level in the peripheral blood (PB) under normal steady-state conditions, maintaining a pool of stem cells in peripheral tissues, and their levels increase in PB during stress/tissue injury, and (ii) they could be chemoattracted to the BM where they find a supportive environment and that the SDF-1-CXCR4 axis plays a prominent role in the homing/retention of these cells to BM niches. We performed all experiments using freshly isolated cells to exclude the potential for 'transdifferentiation' of hematopoietic stem or mesenchymal cells associated with in vitro culture systems. We detected mRNA for various early markers for muscle (Myf-5, Myo-D), neural (GFAP, nestin) and liver (CK19, fetoprotein) cells in circulating (adherent cell-depleted) PB mononuclear cells (MNC) and increased levels of expression of these markers in PB after mobilization by G-CSF (as measured using real-time RT-PCR). Furthermore, SDF-1 chemotaxis combined with real-time RT-PCR analysis revealed that (i) these early tissue-specific cells reside in normal murine BM, (ii) express CXCR4 on their surface and (iii) can be enriched (up to 60 x) after chemotaxis to an SDF-1 gradient. These cells were also highly enriched within purified populations of murine Sca-1(+) BM MNC as well as of human CD34(+)-, AC133(+)- and CXCR4-positive cells. We also found that the expression of mRNA for SDF-1 is upregulated in damaged heart, kidney and liver. Hence our data provide a new perspective on BM not only as a home for hematopoietic stem cells but also a 'hideout' for already differentiated CXCR4-positive tissue-committed stem/progenitor cells that follow an SDF-1 gradient, could be mobilized into PB, and subsequently take part in organ/tissue regeneration.
TL;DR: It is concluded that tenascin C contributes to the generation of a stem cell `niche' within the SVZ, acting to orchestrate growth factor signalling so as to accelerate neural stem cell development.
Abstract: Stem cells in the embryonic mammalian CNS are initially responsive to fibroblast growth factor 2 (FGF2). They then undergo a developmental programme in which they acquire epidermal growth factor (EGF) responsiveness, switch from the production of neuronal to glial precursors and become localized in specialized germinal zones such as the subventricular zone (SVZ). Here we show that extracellular matrix molecules act as regulators of this programme. Tenascin C is highly expressed in the SVZ, and transgenic mice lacking tenascin C show delayed acquisition of the EGF receptor. This results from alterations in the response of the stem cells to the growth factors FGF2 and bone morphogenic protein 4 (BMP4), which normally promote and inhibit acquisition of the EGF receptor, respectively. Tenascin C-deficient mice also have altered numbers of CNS stem cells and these stem cells have an increased probability of generating neurones when grown in cell culture. We conclude that tenascin C contributes to the generation of a stem cell 'niche' within the SVZ, acting to orchestrate growth factor signalling so as to accelerate neural stem cell development.
TL;DR: It is concluded that integrins are therefore an important part of the signalling mechanisms that control neural stem cell behaviour in specific areas of the CNS.
Abstract: The emerging evidence that stem cells develop in specialised niches
highlights the potential role of environmental factors in their regulation.
Here we examine the role of β1 integrin/extracellular matrix interactions
in neural stem cells. We find high levels of β1 integrin expression in
the stem-cell containing regions of the embryonic CNS, with associated
expression of the laminin α2 chain. Expression levels of lamininα
2 are reduced in the postnatal CNS, but a population of cells
expressing high levels of β1 remains. Using neurospheres –
aggregate cultures, derived from single stem cells, that have a
three-dimensional architecture that results in the localisation of the stem
cell population around the edge of the sphere – we show directly thatβ
1 integrins are expressed at high levels on neural stem cells and can be
used for their selection. MAPK, but not PI3K, signalling is required for
neural stem cell maintenance, as assessed by neurosphere formation, and
inhibition or genetic ablation of β1 integrin using cre/lox technology
reduces the level of MAPK activity. We conclude that integrins are therefore
an important part of the signalling mechanisms that control neural stem cell
behaviour in specific areas of the CNS.
TL;DR: It is shown that neurogenesis becomes fully Pax6-dependent in the neurospheres culture system, independent of the region of origin, and that Pax6 overexpression is sufficient to direct almost all neurosphere-derived cells towards neurogen Genesis.
TL;DR: It is suggested that the balance between the mitogenic effects and the proneural effects of beta-catenin is determined by the presence of FGF signaling.
TL;DR: Data demonstrate that striatal transplants of human fetal stem cells elicit behavioral and anatomical recovery in a rodent model of Huntington's disease.
Abstract: The present study investigated the neuroanatomical and behavioral effects of human stem cell transplants into the striatum of quinolinic acid (QA)-lesioned rats Twenty-four rats received unilateral QA (200 nM/microl) injections into the striatum One week later, rats were transplanted with stem cells derived from human fetal cortex (12 weeks postconception) that were either 1) pretreated in culture media with the differentiating cytokine ciliary neurotrophic factor (CNTF; n = 9) or 2) allowed to grow in culture media alone (n=7) Each rat was injected with a total of 200,000 cells A third group of rats (n=8) was given a sham injection of vehicle Rats transplanted with human stem cells performed significantly better over the 8 weeks of testing on the cylinder test compared with those treated with vehicle (P < or = 0001) Stereological striatal volume analyses performed on Nissl-stained sections revealed that rats transplanted with CNTF-treated neurospheres had a 22% greater striatal volume on the lesioned side compared with those receiving transplants of untreated neurospheres (P = 00003) and a 26% greater striatal volume compared with rats injected with vehicle (P < or = 00001) Numerous human nuclei-positive cells were visualized in the striatum in both transplantation groups Grafted cells were also observed in the globus pallidus, entopeduncular nucleus, and substantia nigra pars reticulata, areas of the basal ganglia receiving striatal projections Some of the human nuclei-positive cells coexpressed glial fibrillary acidic protein and NeuN, suggesting that they had differentiated into neurons and astrocytes Taken together, these data demonstrate that striatal transplants of human fetal stem cells elicit behavioral and anatomical recovery in a rodent model of Huntington's disease
TL;DR: This is the first demonstration of CNS stem and progenitor cell-derived functional synapse and neuronal network formation in a 3D matrix, and the proliferative capacity and neuronal differentiating potential of neural progenitors in 3D collagen gels suggest their potential use in attempts to promote neuronal regeneration in vivo.
TL;DR: It is concluded that stem and transient amplifying cells reside in this location, while differentiating (K15 negative) cells are found in the shallow rete ridges of adult skin in situ.
TL;DR: Results illustrate widespread chemokine sensitivity of embryonic and adult neural progenitor cells and support the view that chemokines may be of general importance in control of progenitors cell migration in embryonic andAdult brain.
Abstract: We investigated the expression and functions of chemokine receptors in neural progenitor cells isolated from embryonic and adult mice. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis demonstrated mRNA expression for most known chemokine receptors in neural progenitor cells grown as neurospheres from embryonic (E17) and adult (4-week-old) mice. The expression of CXCR4 receptors was demonstrated further in E17 neurospheres using immunohistochemistry, in situ hybridization, Northern blot analysis and fura-2-based Ca2+ imaging. Most neurospheres grown from E17 mice responded to stromal cell-derived factor-1 (SDF-1/CXCL12) in Ca2+ imaging studies. In addition, immunohistochemical studies demonstrated that these neurospheres consisted of dividing cells that uniformly colocalized nestin and CXCR4 receptors. Differentiation of E17 neurospheres yielded astrocytes and neurons exhibiting several different phenotypes, including expression of calbindin, calretinin, gamma-aminobutyric acid (GABA), and glutamate, and many also coexpressed CXCR4 receptors. In addition, neurospheres grown from the subventricular zone (SVZ) of 4-week-old mice exhibited large increases in Ca2+ in response to CXCL12 and several other chemokines. In comparison, neurospheres prepared from olfactory bulb of adult mice exhibited only small Ca2+ responses to CXCL12, whereas neurospheres prepared from hippocampus were insensitive to CXCL12, although they did respond to other chemokines. Investigations designed to investigate whether CXCL12 can act as a chemoattractant demonstrated that cells dissociated from E17 or adult SVZ neurospheres migrated toward an CXCL12 gradient and this was blocked by the CXCR4 antagonist AMD3100. These results illustrate widespread chemokine sensitivity of embryonic and adult neural progenitor cells and support the view that chemokines may be of general importance in control of progenitor cell migration in embryonic and adult brain. © 2004 Wiley-Liss, Inc.
TL;DR: Adult human skeletal muscle includes a population of progenitor stem cells that can generate cells of the same lineage and cells with neurogenic properties, and may be a tissue source for the isolation of pluripotent stem cells for development of cell-based therapies for human myogenic and neurogenic diseases.
TL;DR: It is demonstrated that leukemia inhibitory factor-dependent (but not FGF2-dependent) sphere-forming cells are present in the earlier (E5.5-E7.5) mouse embryo, suggesting that they are the in vivo cells' equivalent of the primitive neural stem cells that form in vitro from embryonic stem cells.
Abstract: Basic fibroblast growth factor (FGF2)-responsive definitive neural stem cells first appear in embryonic day 8.5 (E8.5) mouse embryos, but not in earlier embryos, although neural tissue exists at E7.5. Here, we demonstrate that leukemia inhibitory factor-dependent (but not FGF2-dependent) sphere-forming cells are present in the earlier (E5.5-E7.5) mouse embryo. The resultant clonal sphere cells possess self-renewal capacity and neural multipotentiality, cardinal features of the neural stem cell. However, they also retain some nonneural properties, suggesting that they are the in vivo cells' equivalent of the primitive neural stem cells that form in vitro from embryonic stem cells. The generation of the in vivo primitive neural stem cell was independent of Notch signaling, but the activation of the Notch pathway was important for the transition from the primitive to full definitive neural stem cell properties and for the maintenance of the definitive neural stem cell state.