Search results for "Stem Cell"
showing 10 items of 2354 documents
Cellular Plasticity in the Adult Murine Piriform Cortex: Continuous Maturation of Dormant Precursors Into Excitatory Neurons
2017
Neurogenesis in the healthy adult murine brain is based on proliferation and integration of stem/progenitor cells and is thought to be restricted to 2 neurogenic niches: the subventricular zone and the dentate gyrus. Intriguingly, cells expressing the immature neuronal marker doublecortin (DCX) and the polysialylated-neural cell adhesion molecule reside in layer II of the piriform cortex. Apparently, these cells progressively disappear along the course of ageing, while their fate and function remain unclear. Using DCX-CreERT2/Flox-EGFP transgenic mice, we demonstrate that these immature neurons located in the murine piriform cortex do not vanish in the course of aging, but progressively res…
Neuronal precursor-specific activity of a human doublecortin regulatory sequence.
2005
The doublecortin (DCX) gene encodes a 40-kDa microtubule-associated protein specifically expressed in neuronal precursors of the developing and adult CNS. Due to its specific expression pattern, attention was drawn to DCX as a marker for neuronal precursors and neurogenesis, thereby underscoring the importance of its promoter identification and promoter analysis. Here, we analysed the human DCX regulatory sequence and confined it to a 3.5-kb fragment upstream of the ATG start codon. We demonstrate by transient transfection experiments that this fragment is sufficient and specific to drive expression of reporter genes in embryonic and adult neuronal precursors. The activity of this regulator…
Dual roles of Aβ in proliferative processes in an amyloidogenic model of Alzheimer’s disease
2017
Alzheimer’s disease is a major neurodegenerative disorder that leads to severe cognitive deficits in the elderly population. Over the past two decades, multiple studies have focused on elucidating the causative factors underlying memory defects in Alzheimer’s patients. In this regard, new evidence linking Alzheimer’s disease-related pathology and neuronal stem cells suggests that hippocampal neurogenesis impairment is an important factor underlying these cognitive deficits. However, because of conflicting results, the impact of Aβ pathology on neurogenesis/gliogenesis remains unclear. Here, we investigated the effect of Aβ on neuronal and glial proliferation by using an APP/PS1 transgenic m…
Expression of the transcription factor Pax6 in the adult rat dentate gyrus
2005
The transcription factor Pax 6 is expressed in precursor cells during embryonic CNS development, and it plays an important role in the regulation of cell proliferation and neuronal fate determination. Pax 6-expressing cells are also present in the adult hippocampal dentate gyrus and subventricular zone/rostral migratory stream, regions in which neuronal precursors exist during adult life. In the adult dentate gyrus, precursor cells are located in the innermost portion of the granule cell layer, and Pax 6-expressing nuclei are most abundant in this region. To examine the putative role of Pax 6 in adult hippocampal neurogenesis, we have studied the proliferative activity, distribution, and ph…
Peroxisome proliferator-activated receptor γ ligands regulate neural stem cell proliferation and differentiation in vitro and in vivo.
2011
Peroxisome proliferator-activated receptor gamma (PPARγ) belongs to a family of ligand-activated nuclear receptors and its ligands are known to control many physiological and pathological situations. Its role in the central nervous system has been under intense analysis during the last years. Here we show a novel function for PPARγ in controlling stem cell expansion in the adult mammalian brain. Adult rats treated with pioglitazone, a specific ligand of PPARγ, had elevated numbers of proliferating progenitor cells in the subventricular zone and the rostral migratory stream. Electron microscopy analysis also showed important changes in the subventricular zone ultrastructure of pioglitazone-t…
Chronic cocaine exposure impairs progenitor proliferation but spares survival and maturation of neural precursors in adult rat dentate gyrus
2006
Recent observations indicate that drugs of abuse, including alcohol and opiates, impair adult neurogenesis in the hippocampus. We have studied in rats the impact of cocaine treatment (20 mg/kg, daily, i.p.) on cell proliferation, survival and maturation following short-term (8-day) and long-term (24-day) exposure. Using 5'-bromo-2-deoxyuridine (BrdU) and Ki-67 as mitotic markers at the end of the drug treatments, we found that both short- and long-term cocaine exposures significantly reduced cell proliferation in the dentate gyrus (DG) of the hippocampus. By labelling mitotic cells with BrdU pulses before or during the early stages of the drug treatment, we determined that long-term cocaine…
Divergent impact of the polysialyltransferases ST8SiaII and ST8SiaIV on polysialic acid expression in immature neurons and interneurons of the adult …
2010
Polysialic acid (PSA) is a negatively charged carbohydrate polymer, which confers antiadhesive properties to the neural cell adhesion molecule NCAM and facilitates cellular plasticity during brain development. In mice, PSA expression decreases drastically during the first postnatal weeks and it gets confined to immature neurons and regions displaying structural plasticity during adulthood. In the brain, PSA is exclusively synthesized by the two polysialyltransferases ST8SiaII and ST8SiaIV. To study their individual contribution to polysialylation in the adult, we analyzed PSA expression in mice deficient for either polysialyltransferase. Focusing on the cerebral cortex, our results indicate…
Subventricular Zone-Derived Neuroblasts Migrate and Differentiate into Mature Neurons in the Post-Stroke Adult Striatum
2006
Recent studies have revealed that the adult mammalian brain has the capacity to regenerate some neurons after various insults. However, the precise mechanism of insult-induced neurogenesis has not been demonstrated. In the normal brain, GFAP-expressing cells in the subventricular zone (SVZ) of the lateral ventricles include a neurogenic cell population that gives rise to olfactory bulb neurons only. Herein, we report evidence that, after a stroke, these cells are capable of producing new neurons outside the olfactory bulbs. SVZ GFAP-expressing cells labeled by a cell-type-specific viral infection method were found to generate neuroblasts that migrated toward the injured striatum after middl…
Functional Integration of Neuronal Precursors in the Adult Murine Piriform Cortex
2018
Abstract The extent of functional maturation and integration of nonproliferative neuronal precursors, becoming neurons in the adult murine piriform cortex, is largely unexplored. We thus questioned whether precursors eventually become equivalent to neighboring principal neurons or whether they represent a novel functional network element. Adult brain neuronal precursors and immature neurons (complex cells) were labeled in transgenic mice (DCX-DsRed and DCX-CreERT2 /flox-EGFP), and their cell fate was characterized with patch clamp experiments and morphometric analysis of axon initial segments. Young (DCX+) complex cells in the piriform cortex of 2- to 4-month-old mice received sparse synapt…
Human adult periodontal ligament-derived cells integrate and differentiate after implantation into the adult mammalian brain.
2013
Previous studies suggest that neural crest (NC)-derived stem cells may reside in NC derivatives including the human periodontal ligament (hPDL). The isolation and manipulation of autologous NC-derived cells could be an accessible source of adult neural stem cells for their use in cell replacement and gene transfer to the diseased central nervous system. In this study, we examined the expression of NC markers and neural differentiation potential of hPDL-derived cells both in vitro and in vivo. In vitro we found that hPDL-derived cells expressed stem cell markers (Oct3/4, Nestin, Sox2, and Musashi-1) and a subset of NC cell markers (Slug, p75(NTR), Twist, and Sox9). hPDL-derived cells differe…