Neural Stem And Progenitor Cells Research Articles

A comparison of proliferative capacity and passaging potential between neural stem and progenitor cells in adherent and neurosphere cultures

Neural stem and progenitor cells (NSPCs) can be isolated from the fetal or adult brain and expanded in culture for potential use in basic research, drug discovery and cell therapy. In the present study, two culture systems have been commonly used to maintain and expand NSPCs isolated from mammalian CNS: neurosphere and adhesive substrate-bound monolayer culture. NSPCs were isolated from the neuroepithelium of E14 embryonic rat cerebral cortex and maintained and expanded on fibronectin substrates or within neurospheres in serum-free medium. Ultrastructural study under transmission electron microscope revealed similar characteristics of immature morphology of NSPCs in adherent and neurosphere cultures. NSPCs cultured on adherent substrates and within neurospheres shared the properties of self-renewal and multipotency, but little is known about proliferation capacity and passaging potential of adherent NSPCs compared to neurosphere culture. We found that the self-renewal capacity of NSPCs in adherent culture was higher than that in neurosphere culture in the P1 and P3 passages, and reduced after the P5 passage. At the same time, comparative analysis using BrdU incorporation and immunostaining for nestin indicated that NSPCs grew significantly faster in primary cultures on adherent substrates than within neurospheres. Whereas, NSPCs in adherent culture could not maintain such robust growth for more than 6 passages. The growth of NSPCs within neurospheres was slower than that in adherent culture, but increased steadily and could be maintained for more than 10 passages. These data provide useful information for large scale in vitro expansion of NSPCs required by potential drug screening and cell therapy.

Isolation and characterization of duck embryonic neural stem and progenitor cells

Both embryonic and adult neural stem cells (NSC) of rodents and humans have been isolated and cultured in vitro to date, and they are thought to have tremendous clinical promise in restoring the diseased or injured central nervous system. However, there are few counterpart reports on neural stem cells from birds. This study explored the isolation and culture system of duck neural stem and progenitor cells (NSPC) and investigated their major biological properties. Cells from the dorsal ventricular ridges of 10- to 13-d embryos were isolated, cultured, and purified by using a neurosphere assay. Growth kinetics and karyotype were analyzed. The differentiation potential of NSPC was detected by immunofluorescence. Apoptosis and acetylation level of histone 4 lysine 12 (H4K12) were assessed. Results indicated that the nestin-positive neurospheres derived from duck embryos were able to self-renew and differentiate into neurons, astrocytes, and oligodendrocytes, and were prone to be transfected with exogenous genes. Karyotype analysis showed that 95% (38 out of 40) of cells of the population were diploid. Apoptosis detection indicated that the apoptotic rate was elevated with increasing passage number and culture time. The cells were highly acetylated and exhibited typical NSPC properties. Efficiently transfected with fluorescent genes, they were available for gene therapy and suitable for research on intracellular distribution of proteins of interest.

The Emerging Role of Epigenetics in Stroke

The transplantation of exogenous stem cells and the activation of endogenous neural stem and progenitor cells (NSPCs) are promising treatments for stroke. These cells can modulate intrinsic responses to ischemic injury and may even integrate directly into damaged neural networks. However, the neuroprotective and neural regenerative effects that can be mediated by these cells are limited and may even be deleterious. Epigenetic reprogramming represents a novel strategy for enhancing the intrinsic potential of the brain to protect and repair itself by modulating pathologic neural gene expression and promoting the recapitulation of seminal neural developmental processes. In fact, recent evidence suggests that emerging epigenetic mechanisms are critical for orchestrating nearly every aspect of neural development and homeostasis, including brain patterning, neural stem cell maintenance, neurogenesis and gliogenesis, neural subtype specification, and synaptic and neural network connectivity and plasticity. In this review, we survey the therapeutic potential of exogenous stem cells and endogenous NSPCs and highlight innovative technological approaches for designing, developing, and delivering epigenetic therapies for targeted reprogramming of endogenous pools of NSPCs, neural cells at risk, and dysfunctional neural networks to rescue and restore neurologic function in the ischemic brain.

Localizing Protein in 3D Neural Stem Cell Culture: a Hybrid Visualization Methodology

The importance of 3-dimensional (3D) topography in influencing neural stem and progenitor cell (NPC) phenotype is widely acknowledged yet challenging to study. When dissociated from embryonic or post-natal brain, single NPCs will proliferate in suspension to form neurospheres. Daughter cells within these cultures spontaneously adopt distinct developmental lineages (neurons, oligodendrocytes, and astrocytes) over the course of expansion despite being exposed to the same extracellular milieu. This progression recapitulates many of the stages observed over the course of neurogenesis and gliogenesis in post-natal brain and is often used to study basic NPC biology within a controlled environment. Assessing the full impact of 3D topography and cellular positioning within these cultures on NPC fate is, however, difficult. To localize target proteins and identify NPC lineages by immunocytochemistry, free-floating neurospheres must be plated on a substrate or serially sectioned. This processing is required to ensure equivalent cell permeabilization and antibody access throughout the sphere. As a result, 2D epifluorescent images of cryosections or confocal reconstructions of 3D Z-stacks can only provide spatial information about cell position within discrete physical or digital 3D slices and do not visualize cellular position in the intact sphere. Here, to reiterate the topography of the neurosphere culture and permit spatial analysis of protein expression throughout the entire culture, we present a protocol for isolation, expansion, and serial sectioning of post-natal hippocampal neurospheres suitable for epifluorescent or confocal immunodetection of target proteins. Connexin29 (Cx29) is analyzed as an example. Next, using a hybrid of graphic editing and 3D modelling softwares rigorously applied to maintain biological detail, we describe how to re-assemble the 3D structural positioning of these images and digitally map labelled cells within the complete neurosphere. This methodology enables visualization and analysis of the cellular position of target proteins and cells throughout the entire 3D culture topography and will facilitate a more detailed analysis of the spatial relationships between cells over the course of neurogenesis and gliogenesis in vitro. Both Imbeault and Valenzuela contributed equally and should be considered joint first authors.

Localizing Protein in 3D Neural Stem Cell Culture: a Hybrid Visualization Methodology

The importance of 3-dimensional (3D) topography in influencing neural stem and progenitor cell (NPC) phenotype is widely acknowledged yet challenging to study. When dissociated from embryonic or post-natal brain, single NPCs will proliferate in suspension to form neurospheres. Daughter cells within these cultures spontaneously adopt distinct developmental lineages (neurons, oligodendrocytes, and astrocytes) over the course of expansion despite being exposed to the same extracellular milieu. This progression recapitulates many of the stages observed over the course of neurogenesis and gliogenesis in post-natal brain and is often used to study basic NPC biology within a controlled environment. Assessing the full impact of 3D topography and cellular positioning within these cultures on NPC fate is, however, difficult. To localize target proteins and identify NPC lineages by immunocytochemistry, free-floating neurospheres must be plated on a substrate or serially sectioned. This processing is required to ensure equivalent cell permeabilization and antibody access throughout the sphere. As a result, 2D epifluorescent images of cryosections or confocal reconstructions of 3D Z-stacks can only provide spatial information about cell position within discrete physical or digital 3D slices and do not visualize cellular position in the intact sphere. Here, to reiterate the topography of the neurosphere culture and permit spatial analysis of protein expression throughout the entire culture, we present a protocol for isolation, expansion, and serial sectioning of post-natal hippocampal neurospheres suitable for epifluorescent or confocal immunodetection of target proteins. Connexin29 (Cx29) is analyzed as an example. Next, using a hybrid of graphic editing and 3D modelling softwares rigorously applied to maintain biological detail, we describe how to re-assemble the 3D structural positioning of these images and digitally map labelled cells within the complete neurosphere. This methodology enables visualization and analysis of the cellular position of target proteins and cells throughout the entire 3D culture topography and will facilitate a more detailed analysis of the spatial relationships between cells over the course of neurogenesis and gliogenesis in vitro.Both Imbeault and Valenzuela contributed equally and should be considered joint first authors.

Isolation and characterization of a population of stem-like progenitor cells from an atypical meningioma

The majority of meningiomas are benign tumors associated with favorable outcomes; however, the less common aggressive variants with unfavorable outcomes often recur and may be due to subpopulations of less-differentiated cells residing within the tumor. These subpopulations of tumor cells have tumor-initiating properties and may be isolated from heterogeneous tumors when sorted or cultured in defined medium. We report the isolation and characterization of a population of tumor-initiating cells derived from an atypical meningioma. We identify a tumor-initiating population from an atypical meningioma, termed meningioma-initiating cells (MICs). These MICs self-renew, differentiate, and can recapitulate the histological characteristics of the parental tumor when transplanted at 1000 cells into the flank regions of athymic nude mice. Immunohistochemistry reveals stem-like protein expression patterns similar to neural stem and progenitor cells (NSPCs) while genomic profiling verified the isolation of cancer cells (with defined meningioma chromosomal aberrations) from the bulk tumor. Microarray and pathway analysis identifies biochemical processes and gene networks related to aberrant cell cycle progression, particularly the loss of heterozygosity of tumor suppressor genes CDKN2A (p16INK4A), p14ARF, and CDKN2B (p15INK4B). Flow cytometric analysis revealed the expression of CD44 and activated leukocyte adhesion molecule (ALCAM/CD166); these may prove to be markers able to identify this cell type. The isolation and identification of a tumor-initiating cell population capable of forming meningiomas demonstrates a useful model for understanding meningioma development. This meningioma model may be used to study the cell hierarchy of meningioma tumorogenesis and provide increased understanding of malignant progression.

Chromatin-Modifying Agents for Epigenetic Reprogramming and Endogenous Neural Stem Cell-Mediated Repair in Stroke

The recent explosion of interest in epigenetics and chromatin biology has made a significant impact on our understanding of the pathophysiology of cerebral ischemia and led to the identification of new treatment strategies for stroke, such as those that employ histone deacetylase inhibitors. These are key advances; however, the rapid pace of discovery in chromatin biology and innovation in the development of chromatin-modifying agents implies there are emerging classes of drugs that may also have potential benefits in stroke. Herein, we discuss how various chromatin regulatory factors and their recently identified inhibitors may serve as drug targets and therapeutic agents for stroke, respectively. These factors primarily include members of the repressor element-1 silencing transcription factor (REST)/neuron-restrictive silencer factor macromolecular complex, polycomb group (PcG) proteins, and associated chromatin remodeling factors, which have been linked to the pathophysiology of cerebral ischemia. Further, we suggest that, because of the key roles played by REST, PcG proteins and other chromatin remodeling factors in neural stem and progenitor cell (NSPC) biology, chromatin-modifying agents can be utilized not only to mitigate ischemic injury directly but also potentially to promote endogenous NSPC-mediated brain repair mechanisms.

Evidence for and against regional differences in neural stem and progenitor cells of the CNS: Figure 1.

Neural stem and progenitor cells (NSCs) give rise to the cellular diversity of the CNS. There is evidence both for and against differences in these cells based on the region of the brain in which they reside. Primary brain tumors mimic many aspects of NSC behavior. Recent data suggest that some of the variability in glioma biology may be, in part, a reflection of regional differences in the NSCs from which they arise. In this issue of Genes & Development, Lee and colleagues (pp. 2317-2329) examine how NF1 regulates NSC proliferation and glial differentiation in the brainstem and cortex of the postnatal mouse brain.

Seeing beyond the average cell: branching process models of cell proliferation, differentiation, and death during mouse brain development

We develop a family of branching process models to study cerebral cortical development at the level of individual neural stem and progenitor cells (NS/PCs) and the neurons they produce. Population-level data about "the average NS/PC" is incorporated as constraints for exploring (i) heterogeneity in the proliferative neural cell types and (ii) variability in daughter cell fate decision making. Preliminary studies demonstrate this variability, generate testable hypotheses about heterogeneity, and motivate new experiments moving forward.

Pannexin 2 Is Expressed by Postnatal Hippocampal Neural Progenitors and Modulates Neuronal Commitment

The pannexins (Panx1, -2, and -3) are a mammalian family of putative single membrane channels discovered through homology to invertebrate gap junction-forming proteins, the innexins. Because connexin gap junction proteins are known regulators of neural stem and progenitor cell proliferation, migration, and specification, we asked whether pannexins, specifically Panx2, play a similar role in the postnatal hippocampus. We show that Panx2 protein is differentially expressed by multipotential progenitor cells and mature neurons. Both in vivo and in vitro, Type I and IIa stem-like neural progenitor cells express an S-palmitoylated Panx2 species localizing to Golgi and endoplasmic reticulum membranes. Protein expression is down-regulated during neurogenesis in neuronally committed Type IIb and III progenitor cells and immature neurons. Panx2 is re-expressed by neurons following maturation. Protein expressed by mature neurons is not palmitoylated and localizes to the plasma membrane. To assess the impact of Panx2 on neuronal differentiation, we used short hairpin RNA to suppress Panx2 expression in Neuro2a cells. Knockdown significantly accelerated the rate of neuronal differentiation. Neuritic extension and the expression of antigenic markers of mature neurons occurred earlier in stable lines expressing Panx2 short hairpin RNA than in controls. Together, these findings describe an endogenous post-translational regulation of Panx2, specific to early neural progenitor cells, and demonstrate that this expression plays a role in modulating the timing of their commitment to a neuronal lineage.

Smad7 Regulates the Adult Neural Stem/Progenitor Cell Pool in a Transforming Growth Factor β- and Bone Morphogenetic Protein-Independent Manner

Members of the transforming growth factor beta (TGF-beta) family of proteins modulate the proliferation, differentiation, and survival of many different cell types. Neural stem and progenitor cells (NPCs) in the adult brain are inhibited in their proliferation by TGF-beta and by bone morphogenetic proteins (BMPs). Here, we investigated neurogenesis in a hypomorphic mouse model for the TGF-beta and BMP inhibitor Smad7, with the hypothesis that NPC proliferation might be reduced due to increased TGF-beta and BMP signaling. Unexpectedly, we found enhanced NPC proliferation as well as an increased number of label-retaining cells in vivo. The enhanced proliferation potential of mutant cells was retained in vitro in neurosphere cultures. We observed a higher sphere-forming capacity as well as faster growth and cell cycle progression. Use of specific inhibitors revealed that these effects were independent of TGF-beta and BMP signaling. The enhanced proliferation might be at least partially mediated by elevated signaling via epidermal growth factor (EGF) receptor, as mutant cells showed higher expression and activation levels of the EGF receptor. Conversely, an EGF receptor inhibitor reduced the proliferation of these cells. Our data indicate that endogenous Smad7 regulates neural stem/progenitor cell proliferation in a TGF-beta- and BMP-independent manner.

Targeting CREB signalling in neurogenesis

Importance of the field: Expansion and ultimately homeostasis of neural cell number is exquisitely regulated by molecular genetic networks operating in neural stem and progenitor cells (NSPCs) and in the neural stem cell niche during embryogenesis and in the adult brain. Transcription factors are crucial in orchestrating the correct cell-specific and temporal expression of all factors involved in these signalling networks. Aberrant expression of these factors can lead to abnormal brain development if this occurs during embryogenesis. In the adult brain, loss of neurogenic potential can lead to cognitive deficits and in combination with neural death can even contribute to neurodegenerative disease progress.Areas covered in this review: This review focuses on a number of recent discoveries identifying the role of the transcription factor cAMP response element binding (CREB) protein in regulating brain development and neurogenesis in the adult brain.What the reader will gain: The significance of these discoveries is presented in the context of human brain disorders and how this knowledge could contribute to pharmacotherapeutic interventions targeting CREB signalling aimed at treating such diseases.Take home message: Unravelling these precise molecular genetic networks is crucial to understanding how neural stem and progenitor cells function

A novel classification of quiescent and transit amplifying adult neural stem cells by surface and metabolic markers permits a defined simultaneous isolation

Adult neural stem and progenitor cells (NSPCs) are usually defined retrospectively by their ability to proliferate in vivo (bromodeoxyuridine uptake) or to form neurospheres and to differentiate into neurons, astrocytes and oligodendrocytes in vitro. Additional strategies to identify and to isolate NSPCs are of great importance for the investigation of cell differentiation and fate specification. Using the cell surface molecules Prominin-1 and Lewis X and a metabolic marker, the aldehyde dehydrogenase activity, we isolated and characterized five main populations of NSPCs in the neurogenic subventricular zone (SVZ) and the non-neurogenic spinal cord (SC). We used clonal analysis to assess neurosphere formation and multipotency, BrdU retention to investigate in vivo proliferation activity and quantified the expression of NSPC associated genes. Surprisingly, we found many similarities in NSPC subpopulations derived from the SVZ and SC suggesting that subtypes with similar intrinsic potential exist in both regions. The marker defined classification of NSPCs will help to distinguish subpopulations of NSPCs and allows their prospective isolation using fluorescence activated cell sorting.

The effect of epidermal growth factor in the injured brain after trauma in rats.

Epidermal growth factor (EGF) is a known mitogen for neural stem and progenitor cells (NS/NPCs) in the central nervous system (CNS). In vitro, EGF maintains NS/NPCs in the proliferative state, whereas in the normal rodent brain it promotes their proliferation and migration in the subventricular zone (SVZ). Additionally, EGF administration can augment neuronal replacement in the ischemic-injured adult striatum. Recently we found that the SVZ and the hippocampus display an injury-induced proliferative response following traumatic brain injury (TBI) that is linked to increased EGF expression. As adult neurogenesis is associated with cognitive function, we hypothesized that post-TBI administration of EGF could affect neurogenesis and cognitive recovery. Adult rats were intraventricularly infused with EGF or vehicle for 7 days following TBI. 5-Bromo-2-deoxyuridine (BrdU) was administered to label proliferating cells and the animals were sacrificed at 1 or 4 weeks post-injury. Using immunohistochemistry and stereology, we found that at 1 week post-injury, compared to vehicle-infused animals EGF-infused animals had significantly more BrdU-positive cells in the SVZ and hippocampus concomitant with enhanced EGF receptor expression. At 4 weeks post-injury, the number of BrdU-positive cells in the hippocampus was similar in both groups, suggesting that EGF does not support long-term survival of newly generated cells. Furthermore, we found that the EGF-induced proliferative population differentiated preferentially toward astroglial phenotype. Nevertheless, animals treated with EGF showed significant improvement in cognitive function, which was accompanied by reduced hippocampal neuronal cell loss. Collectively, the data from this study demonstrate that EGF exerts a neuroprotective rather than neurogenic effect in protecting the brain from injury.

Chemokine expression in the white matter spinal cord precursor niche after force‐defined spinal cord contusion injuries in adult rats

Inflammatory cascades induced by spinal cord injuries (SCI) are localized in the white matter, a recognized neural stem- and progenitor-cell (NSPC) niche of the adult spinal cord. Chemokines, as integrators of these processes, might also be important determinants of this NSPC niche. CCL3/CCR1, CCL2/CCR2, and SDF-1alpha/CXCR4 were analyzed in the ventrolateral white matter after force defined thoracic SCI: Immunoreactivity (IR) density levels were measured 2 d, 7 d, 14 d, and 42 d on cervical (C 5), thoracic (T 5), and lumbar (L 5) levels. On day post operation (DPO) 42, chemokine inductions were further evaluated by real-time RT-PCR and Western blot analyses. Cellular phenotypes were confirmed by double labeling with markers for major cell types and NSPCs (nestin, Musashi-1, NG2, 3CB2, BLBP). Mitotic profiles were investigated in parallel by BrdU labeling. After lesion, chemokines were induced in the ventrolateral white matter on IR-, mRNA-, and protein-level. IR was generally more pronounced after severe lesions, with soaring increases of CCL2/CCR2 and continuous elevations of CCL3/CCR1. SDF-1alpha and CXCR4 IR induction was focused on thoracic levels. Chemokines/-receptors were co-expressed with astroglial, oligodendroglial markers, nestin, 3CB2 and BLBP by cells morphologically resembling radial glia on DPO 7 to DPO 42, and NG2 or Musashi-1 on DPO 2 and 7. In the white matter BrdU positive cells were significantly elevated after lesion compared with sham controls on all investigated time points peaking in the early time course on thoracic level: Here, chemokines were co-expressed by subsets of BrdU-labeled cells. These findings suggest an important role of chemokines/-receptors in the subpial white matter NSPC niche after SCI.

Identification of Differentially Expressed Proteins in Murine Embryonic and Postnatal Cortical Neural Progenitors

BackgroundThe central nervous system (CNS) develops from a heterogeneous pool of neural stem and progenitor cells (NSPC), the underlying differences among which are poorly understood. The study of NSPC would be greatly facilitated by the identification of additional proteins that mediate their function and that would distinguish amongst different progenitor populations.Methodology/Principal FindingsTo identify membrane and membrane-associated proteins expressed by NSPC, we used a proteomics approach to profile NSPC cultured as neurospheres (NS) isolated from the murine cortex during a period of neurogenesis (embryonic day 11.5, E11.5), as compared to NSPC isolated at a peak of gliogenesis (postnatal day 1, P0) and to differentiated E11.5 NS. 54 proteins were identified with high expression in E11.5 NS, including the TrkC receptor, several heterotrimeric G proteins, and the Neogenin receptor. 24 proteins were identified with similar expression in E11.5 and P0 NS over differentiated E11.5 NS, and 13 proteins were identified with high expression specifically in P0 NS compared to E11.5 NS. To illustrate the potential relevance of these identified proteins to neural stem cell biology, the function of Neogenin was further studied. Using Fluorescence Activated Cell Sorting (FACS) analysis, expression of Neogenin was associated with a self-renewing population present in both E11.5 and adult subventricular zone (SVZ) NS but not in P0 NS. E11.5 NS expressed a putative Neogenin ligand, RGMa, and underwent apoptosis when exposed to a ligand-blocking antibody.Conclusions/SignificanceThere are fundamental differences between the continuously self-renewing and more limited progenitors of the developing cortex. We identified a subset of differentially expressed proteins that serve not only as a set of functionally important proteins, but as a useful set of markers for the subsequent analysis of NSPC. Neogenin is associated with the continuously self-renewing and neurogenic cells present in E11.5 cortical and adult SVZ NS, and the Neogenin/RGMa receptor/ligand pair may regulate cell survival during development.

Genetic instability and diminished differentiation capacity in long-term cultured mouse neurosphere cells

The potential use of neural stem cells in basic research, drug testing and for development of therapeutic strategies requires large scale in vitro amplification, increasing the probability of genetic instability and transformation. Little is known, however, about potential correlations between long-term culture of neural stem and progenitor cells (NSPCs), changed differentiation and self-renewal capacities, and the occurrence of chromosomal instability. This study investigates the effect of extended culture time on self-renewal, differentiation capacity, cell cycle phase distribution, telomere length, telomerase activity and chromosomal stability on fetal brain-derived cells that form floating sphere colonies (neurospheres). We observed that increased sphere-forming capacity indicative of increased proliferation was accompanied by a decreased ability to differentiate into neural lineages. The high mobility group A (Hmga2) gene positively regulates self-renewal via repression of p16(Ink4a) and p19(ARF) gene expression. This study discerned an upregulation of Hmga2 gene and protein expression and decreased p16(Ink4a) and p19(ARF) gene expression, suggesting that Hmga2 might promote the proliferation of neurosphere cells in long-term culture. Further, our analyses revealed a significant decrease in telomere length after 4 weeks of culturing that is paralleled by a moderate upregulation of telomerase activity. Importantly, regular gain of chromosome 1 with random structural chromosomal aberrations was observed within 16 weeks of neurosphere cell culture. Genetic instability and diminished differentiation capacity seem to be a consequence of long-term culture of neurosphere cells. These data indicate the necessity to analyze self-renewal, differentiation capacity, telomere length, tumor suppressor genes and chromosomal stability in neurosphere cultures prior to their usage in basic research, drug testing or the development of therapeutic strategies.

AMP-Activated Protein Kinase Phosphorylates Retinoblastoma Protein to Control Mammalian Brain Development

AMP-activated protein kinase (AMPK) is an evolutionarily conserved metabolic sensor that responds to alterations in cellular energy levels to maintain energy balance. While its role in metabolic homeostasis is well documented, its role in mammalian development is less clear. Here we demonstrate that mutant mice lacking the regulatory AMPK beta1 subunit have profound brain abnormalities. The beta1(-/-) mice show atrophy of the dentate gyrus and cerebellum, and severe loss of neurons, oligodendrocytes, and myelination throughout the central nervous system. These abnormalities stem from reduced AMPK activity, with ensuing cell cycle defects in neural stem and progenitor cells (NPCs). The beta1(-/-) NPC deficits result from hypophosphorylation of the retinoblastoma protein (Rb), which is directly phosphorylated by AMPK at Ser(804). The AMPK-Rb axis is utilized by both growth factors and energy restriction to increase NPC growth. Our results reveal that AMPK integrates growth factor signaling with cell cycle control to regulate brain development.

Ibuprofen attenuates the inflammatory response and allows formation of migratory neuroblasts from grafted stem cells after traumatic brain injury

There is hope for neural stem and progenitor cells (NSPC) to enhance regeneration when transplanted to the injured brain after traumatic brain injury (TBI). So far, the therapeutic effects of NSPC transplantation have been hampered mainly by the notable death of the transplanted cells. Neuroinflammation may lead to additional cell death after TBI and we hypothesized that survival of grafted NSPC could be enhanced by anti-inflammatory treatment. Mice that were subjected to controlled cortical impact TBI and grafted with NSPC, were treated with the non-steroidal anti-inflammatory drug ibuprofen. Ibuprofen was found to down-regulate the TBI-induced inflammatory response. In addition, migrating neuroblasts from transplanted cells were observed near the contusion and in the ipsilateral hippocampus in ibuprofen-treated animals only, suggesting that the anti-inflammatory treatment had beneficial effects on graft survival and/or differentiation. However, Morris Water Maze performance or TBI-induced tissue loss was not influenced by ibuprofen treatment. Our data suggests that anti-inflammatory strategies may be a complement to enhance the outcome for the cell transplants following TBI.

Grafted neural progenitors migrate and form neurons after experimental traumatic brain injury

Neural stem and progenitor cells (NSPC) generate neurons and glia, a feature that makes them attractive for cell replacement therapies. However, efforts to transplant neural progenitors in animal models of brain injury typically result in high cell mortality and poor neuronal differentiation. In an attempt to improve the outcome for grafted NSPC after controlled cortical impact we transplanted Enhanced Green Fluorescent Protein (EGFP)-positive NSPC into the contra lateral ventricle of mice one week after injury. Grafted EGFP-NSPC readily migrated to the injured hemisphere where we analyzed the proportion of progenitors and differentiated progeny at different time points. Transplantation directly into the injured parenchyma, resulted in few brains with detectable EGFP-NSPC. On the contrary, in more than 90% of the mice that received a transplant into the lateral ventricle detectable EGFP-positive cells were found. The cells were integrated into the lateral ventricle wall of the un-injured hemisphere, throughout the corpus callosum, and in the cortical perilesional area. At one-week post transplantation, grafted cells that had migrated to the perilesion area mainly expressed markers of neural progenitors and neurons, while in the corpus callosum and the ventricular lining, grafted cells with a glial fate were more abundant. After 3 months, grafted cells in the perilesion area were less abundant whereas cells that had migrated to the walls of the third- and lateral- ventricle of the injured hemisphere were still detectable, suggesting that the injury site remained a hostile environment. Transplantation to the lateral ventricle, presumably for being a neurogenic region, provides a favorable environment improving the outcome for grafted NSPC both in term of their appearance at the cortical site of injury, and their acquisition of neural markers.