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Migratory Stream (migratory + stream)
Kinds of Migratory Stream Selected AbstractsIdentification of a Chr 11 quantitative trait locus that modulates proliferation in the rostral migratory stream of the adult mouse brainEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2010Anna Poon Abstract Neuron production takes place continuously in the rostral migratory stream (RMS) of the adult mammalian brain. The molecular mechanisms that regulate progenitor cell division and differentiation in the RMS remain largely unknown. Here, we surveyed the mouse genome in an unbiased manner to identify candidate gene loci that regulate proliferation in the adult RMS. We quantified neurogenesis in adult C57BL/6J and A/J mice, and 27 recombinant inbred lines derived from those parental strains. We showed that the A/J RMS had greater numbers of bromodeoxyuridine-labeled cells than that of C57BL/6J mice with similar cell cycle parameters, indicating that the differences in the number of bromodeoxyuridine-positive cells reflected the number of proliferating cells between the strains. AXB and BXA recombinant inbred strains demonstrated even greater variation in the numbers of proliferating cells. Genome-wide mapping of this trait revealed that chromosome 11 harbors a significant quantitative trait locus at 116.75 ± 0.75 Mb that affects cell proliferation in the adult RMS. The genomic regions that influence RMS proliferation did not overlap with genomic regions regulating proliferation in the adult subgranular zone of the hippocampal dentate gyrus. On the contrary, a different, suggestive locus that modulates cell proliferation in the subgranular zone was mapped to chromosome 3 at 102 ± 7 Mb. A subset of genes in the chromosome 11 quantitative trait locus region is associated with neurogenesis and cell proliferation. Our findings provide new insights into the genetic control of neural proliferation and an excellent starting point to identify genes critical to this process. [source] Lineage analysis of quiescent regenerative stem cells in the adult brain by genetic labelling reveals spatially restricted neurogenic niches in the olfactory bulbEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009Claudio Giachino Abstract The subventricular zone (SVZ) of the lateral ventricles is the major neurogenic region in the adult mammalian brain, harbouring neural stem cells within defined niches. The identity of these stem cells and the factors regulating their fate are poorly understood. We have genetically mapped a population of Nestin-expressing cells during postnatal development to study their potential and fate in vivo. Taking advantage of the recombination characteristics of a nestin::CreERT2 allele, we followed a subpopulation of neural stem cells and traced their fate in a largely unrecombined neurogenic niche. Perinatal nestin::CreERT2 -expressing cells give rise to multiple glial cell types and neurons, as well as to stem cells of the adult SVZ. In the adult SVZ nestin::CreERT2 -expressing neural stem cells give rise to several neuronal subtypes in the olfactory bulb (OB). We addressed whether the same population of neural stem cells play a role in SVZ regeneration. Following anti-mitotic treatment to eliminate rapidly dividing progenitors, relatively quiescent nestin::CreERT2 -targeted cells are spared and contribute to SVZ regeneration, generating new proliferating precursors and neuroblasts. Finally, we have identified neurogenic progenitors clustered in ependymal-like niches within the rostral migratory stream (RMS) of the OB. These OB-RMS progenitors generate neuroblasts that, upon transplantation, graft, migrate and differentiate into granule and glomerular neurons. In summary, using conditional lineage tracing we have identified neonatal cells that are the source of neurogenic and regenerative neural stem cells in the adult SVZ and occupy a novel neurogenic niche in the OB. [source] Olfactory bulb hypoplasia in Prokr2 null mice stems from defective neuronal progenitor migration and differentiationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2007Haydn M. Prosser Abstract New neurons are added on a daily basis to the olfactory bulb (OB) of a mammal, and this phenomenon exists throughout its lifetime. These new cells are born in the subventricular zone and migrate to the OB via the rostral migratory stream (RMS). To examine the role of the prokineticin receptor 2 (Prokr2) in neurogenesis, we created a Prokr2 null mouse, and report a decrease in the volume of its OB and also a decrease in the number of bromodeoxyuridine (BrdU)-positive cells. There is disrupted architecture of the OB, with the glomerular layer containing terminal dUTP nick-end labeling (TUNEL) -positive nuclei and also a decrease in tyrosine hydroxylase-positive neurons in this layer. In addition, there are increased numbers of doublecortin-positive neuroblasts in the RMS and increased PSA-NCAM (polysialylated form of the neural cell adhesion molecule) -positive neuronal progenitors around the olfactory ventricle, indicating their detachment from homotypic chains is compromised. Finally, in support of this, Prokr2-deficient cells expanded in vitro as neurospheres are incapable of migrating towards a source of recombinant human prokineticin 2 (PROK2). Together, these findings suggest an important role for Prokr2 in OB neurogenesis. [source] Subventricular zone-derived neuroblast migration to the olfactory bulb is modulated by matrix remodellingEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2007Serena Bovetti Abstract In the rodent brain neural progenitor cells are born in the subventricular zone and migrate along a pathway called the rostral migratory stream (RMS) into the olfactory bulb where they differentiate into several classes of interneurones. In the adult, tangential migration in the RMS takes place in ,chains' of cells contained within glial tubes. In contrast, neonatal neuroblasts along the RMS lack these defined glial tubes and chains, migrating instead as individual cells. Time-lapse confocal microscopy of neuroblasts at each of these ages shows that individual cells migrate in a saltatory manner with bursts of high speed followed by periods of slower speed. Tangential migration within a glial tube is 20% faster than migration as individual cells. Neuroblasts may also interact and modify the extracellular matrix during migration through expression of a family of proteins, the matrix metalloproteinases (MMPs). MMPs are present and active along the subventricular zone,olfactory bulb pathway. In the presence of inhibitors of MMPs, neuroblast migration rates were reduced only when cells migrate individually. Chain migration in the adult was unaffected by MMP inhibitors. Taken together, these data suggest that MMPs only influence migration as individual cells and not as chains. [source] Nurses on the Move: A Global OverviewHEALTH SERVICES RESEARCH, Issue 3p2 2007Mireille Kingma Objective. To look at nurse migration flows in the light of national nursing workforce imbalances, examine factors that encourage or inhibit nurse mobility, and explore the potential benefits of circular migration. Principal Findings. The number of international migrants has doubled since 1970 and nurses are increasingly part of the migratory stream. Critical nursing shortages in industrialized countries are generating a demand that is fueling energetic international recruitment campaigns. Structural adjustments in the developing countries have created severe workforce imbalances and shortfalls often coexist with large numbers of unemployed health professionals. A nurse's motivation to migrate is multifactorial, not limited to financial incentives, and barriers exist that discourage or slow the migration process. The migration flows vary in direction and magnitude over time, responding to socioeconomic factors present in source and destination countries. The dearth of data on which to develop international health human resource policy remains. There is growing recognition, however, that migration will continue and that temporary migration will be a focus of attention in the years to come. Conclusions. Today's search for labor is a highly organized global hunt for talent that includes nurses. International migration is a symptom of the larger systemic problems that make nurses leave their jobs. Nurse mobility becomes a major issue only in a context of migrant exploitation or nursing shortage. Injecting migrant nurses into dysfunctional health systems,ones that are not capable of attracting and retaining staff domestically,will not solve the nursing shortage. [source] Longterm quiescent cells in the aged human subventricular neurogenic system specifically express GFAP-,AGING CELL, Issue 3 2010Simone A. Van Den Berge Summary A main neurogenic niche in the adult human brain is the subventricular zone (SVZ). Recent data suggest that the progenitors that are born in the human SVZ migrate via the rostral migratory stream (RMS) towards the olfactory bulb (OB), similar to what has been observed in other mammals. A subpopulation of astrocytes in the SVZ specifically expresses an assembly-compromised isoform of the intermediate filament protein glial fibrillary acidic protein (GFAP-,). To further define the phenotype of these GFAP-, expressing cells and to determine whether these cells are present throughout the human subventricular neurogenic system, we analysed SVZ, RMS and OB sections of 14 aged brain donors (ages 74-93). GFAP-, was expressed in the SVZ along the ventricle, in the RMS and in the OB. The GFAP-, cells in the SVZ co-expressed the neural stem cell (NSC) marker nestin and the cell proliferation markers proliferating cell nuclear antigen (PCNA) and Mcm2. Furthermore, BrdU retention was found in GFAP-, positive cells in the SVZ. In the RMS, GFAP-, was expressed in the glial net surrounding the neuroblasts. In the OB, GFAP-, positive cells co-expressed PCNA. We also showed that GFAP-, cells are present in neurosphere cultures that were derived from SVZ precursors, isolated postmortem from four brain donors (ages 63-91). Taken together, our findings show that GFAP-, is expressed in an astrocytic subpopulation in the SVZ, the RMS and the OB. Importantly, we provide the first evidence that GFAP-, is specifically expressed in longterm quiescent cells in the human SVZ, which are reminiscent of NSCs. [source] Doublecortin-expressing cells in the ischemic penumbra of a small-vessel strokeJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2008Rui Hua Abstract A cortical lesion was induced by disrupting the medium-size pial vessels, which led to a cone-shaped cortical lesion and turned into a fluid-filled cavity surrounded by a glial acidic fibrillary protein-positive (GFAP+) glia limitans 21 days after injury. Therefore, it mimics conditions of lacunar infarctions, one of the most frequent human stroke pathologies. Doublecortin (DCX)-positive cells were present in the neocortex and corpus callosum at the base of the lesion. The number of DCX-positive cells in the corpus callosum was significantly increased from day 5 to day 14 compared with the control group. In contrast, there were no DCX-positive cells in neocortex of control animals; the DCX-positive cells appeared in the neocortex after lesioning and were maintained until 14 days postlesioning. Some of the DCX-positive cells were also immunoreactive for ,III-tubulin, another marker of immature neurons. They did not stain positively for markers of glia cells. The presence of these DCX-positive cells near the lesion might indicate a migratory pathway for developing neuroblasts from the subventricular zone (SVZ) through the corpus callosum to the lesion. SVZ cells were labeled with a lipophilic molecule, 5- (and 6-) carboxyfluorescein diacetate succinimidyl ester (CFSE) stereotaxical injections. Although rostral migratory stream and olfactory bulb were intensely labeled, no CFSE-containing cells were found in the cortex beneath the lesion. These results do not support the idea that the DCX-positive cells were originating from neural precursors of the SVZ, but they might be generated from local progenitor cells. © 2007 Wiley-Liss, Inc. [source] Enhanced proliferation of progenitor cells in the subventricular zone and limited neuronal production in the striatum and neocortex of adult macaque monkeys after global cerebral ischemia,JOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2005Anton B. Tonchev Abstract Cerebral ischemia in adult rodent models increases the proliferation of endogenous neural progenitor cells residing in the subventricular zone along the anterior horn of the lateral ventricle (SVZa) and induces neurogenesis in the postischemic striatum and cortex. Whether the adult primate brain preserves a similar ability in response to an ischemic insult is uncertain. We used the DNA synthesis indicator bromodeoxyuridine (BrdU) to label newly generated cells in adult macaque monkeys and show here that the proliferation of cells with a progenitor phenotype (double positive for BrdU and the markers Musashi1, Nestin, and ,III-tubulin) in SVZa increased during the second week after a 20-min transient global brain ischemia. Subsequent progenitor migration seemed restricted to the rostral migratory stream toward the olfactory bulb and ischemia increased the proportion of adult-generated cells retaining their location in SVZa with a progenitor phenotype. Despite the lack of evidence for progenitor cell migration toward the postischemic striatum or prefrontal neocortex, a small but sustained proportion of BrdU-labeled cells expressed features of postmitotic neurons (positive for the protein NeuN and the transcription factors Tbr1 and Islet1) in these two regions for at least 79 days after ischemia. Taken together, our data suggest an enhanced neurogenic response in the adult primate telencephalon after a cerebral ischemic insult. © 2005 Wiley-Liss, Inc. [source] Expression of synapsin III in nerve terminals and neurogenic regions of the adult brainTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 2 2002Vincent A. Pieribone Abstract We have examined the distribution of synapsin III in the adult mouse brain. Expression of synapsin III was observed in puncta throughout the brain, but demonstrated greater regional variation than that of synapsins I or II. This punctate staining is typical for synaptic vesicle proteins located at nerve terminals. These findings are also consistent with the well-established role for synapsins in regulating neurotransmitter release. However, unexpectedly, synapsin III was also highly expressed in the cell body and processes of immature neurons in neurogenic regions of the adult brain, such as the hippocampal dentate gyrus, rostral migratory stream, and olfactory bulb. Many synapsin III-positive neurons also reacted with an antibody directed toward polysialylated-neuronal cell adhesion molecule, a marker of immature, migrating neurons. These results suggest that synapsin III may also play a role in adult neurogenesis. J. Comp. Neurol. 454:105,114, 2002. © 2002 Wiley-Liss, Inc. [source] | ||||||||||