Cell Lineage and Regional Identity of Cultured Spinal Cord Neural Stem Cells and Comparison to Brain-Derived Neural Stem Cells

Neural stem cells (NSCs) can be isolated from different regions of the central nervous system. There has been controversy whether regional differences amongst stem and progenitor cells are cell intrinsic and whether these differences are maintained during expansion in culture. The identification of inherent regional differences has important implications for the use of these cells in neural repair. Here, we compared NSCs derived from the spinal cord and embryonic cortex. We found that while cultured cortical and spinal cord derived NSCs respond similarly to mitogens and are equally neuronogenic, they retain and maintain through multiple passages gene expression patterns indicative of the region from which they were isolated (e.g Emx2 and HoxD10). Further microarray analysis identified 229 genes that were differentially expressed between cortical and spinal cord derived neurospheres, including many Hox genes, Nuclear receptors, Irx3, Pace4, Lhx2, Emx2 and Ntrk2. NSCs in the cortex express LeX. However, in the embryonic spinal cord there are two lineally related populations of NSCs: one that expresses LeX and one that does not. The LeX negative population contains few markers of regional identity but is able to generate LeX expressing NSCs that express markers of regional identity. LeX positive cells do not give rise to LeX-negative NSCs. These results demonstrate that while both embryonic cortical and spinal cord NSCs have similar self-renewal properties and multipotency, they retain aspects of regional identity, even when passaged long-term in vitro. Furthermore, there is a population of a LeX negative NSC that is present in neurospheres derived from the embryonic spinal cord but not the cortex.     

Protective roles of melatonin in central nervous system diseases by regulation of neural stem cells

Neural stem cells (NSCs) are immature precursors of the central nervous system (CNS), with self‐renewal and multipotential differentiation abilities. Their proliferation and differentiation are dynamically regulated by hormonal and local factors. Alteration in neurogenesis is associated with many neurological disorders. Increasing evidence suggests that modulation of NSCs can be a promising therapeutic approach for neural injury and neurodegenerative disorders. Melatonin, a pineal gland‐derived hormone, regulates the neuroimmuno‐endocrine axis and is functionally important to the circadian rhythm, tumour suppression and immunity. In the CNS, melatonin exerts neuroprotective effects in many diseases, such as Parkinson's disease, Alzheimer's disease and ischaemic brain injury. Emerging evidence suggests that it might also mediate such protective action by influencing proliferation and differentiation of NSCs. In this article, we review the current literature concerned with effects of melatonin on NSCs in different physiological and pathological conditions.     

In vivo fate analysis reveals the multipotent and self-renewal capacities of Sox2+ neural stem cells in the adult hippocampus

To characterize the properties of adult neural stem cells (NSCs), we generated and analyzed Sox2-GFP transgenic mice. Sox2-GFP cells in the subgranular zone (SGZ) express markers specific for progenitors, but they represent two morphologically distinct populations that differ in proliferation levels. Lentivirus- and retrovirus-mediated fate-tracing studies showed that Sox2+ cells in the SGZ have potential to give rise to neurons and astrocytes, revealing their multipotency at the population as well as at a single-cell level. A subpopulation of Sox2+ cells gives rise to cells that retain Sox2, highlighting Sox2+ cells as a primary source for adult NSCs. In response to mitotic signals, increased proliferation of Sox2+ cells is coupled with the generation of Sox2+ NSCs as well as neuronal precursors. An asymmetric contribution of Sox2+ NSCs may play an important role in maintaining the constant size of the NSC pool and producing newly born neurons during adult neurogenesis.     

Regeneration of the central nervous system using endogenous repair mechanisms

Recent advances in developmental and stem cell biology have made regeneration-based therapies feasible as therapeutic strategies for patients with damaged central nervous systems (CNSs), including those with spinal cord injuries, Parkinson disease, or stroke. These strategies can be classified into two approaches: (i) the replenishment of lost neural cells and (ii) the induction of axonal regeneration. The first approach includes the activation of endogenous neural stem cells (NSCs) in the adult CNS and cell transplantation therapy. Endogenous NSCs have been shown to give rise to new neurons after insults, including ischemia, have been sustained; this form of neurogenesis followed by the migration and functional maturation of neuronal cells, as well as the responses of glial cells and the vascular system play crucial roles in endogenous repair mechanisms in damaged CNS tissue. In this review, we will summarize the recent advances in regeneration-based therapeutic approaches using endogenous NSCs, including the results of our own collaborative groups.     

Notch: from neural development to neurological disorders

Notch is an integral membrane protein that functions as receptor for ligands such as jagged and delta that are associated with the surface of neighboring cells. Upon ligand binding, notch is proteolytically cleaved within its transmembrane domain by presenilin‐1 (the enzymatic component of the γ‐secretase complex) resulting in the release of a notch intracellular domain which translocates to the nucleus where it regulates gene expression. Notch signaling plays multiple roles in the development of the CNS including regulating neural stem cell (NSC) proliferation, survival, self‐renewal and differentiation. Notch is also present in post‐mitotic neurons in the adult CNS wherein its activation influences structural and functional plasticity including processes involved in learning and memory. Recent findings suggest that notch signaling in neurons, glia, and NSCs may be involved in pathological changes that occur in disorders such as stroke, Alzheimer’s disease and CNS tumors. Studies of animal models suggest the potential of agents that target notch signaling as therapeutic interventions for several different CNS disorders.     

Stem Cell Markers in Gliomas

Gliomas are the most common tumours of the central nervous system (CNS) and a frequent cause of mental impairment and death. Treatment of malignant gliomas is often palliative because of their infiltrating nature and high recurrence. Genetic events that lead to brain tumours are mostly unknown. A growing body of evidence suggests that gliomas may rise from cancer stem cells (CSC) sharing with neural stem cells (NSC) the capacity of cell renewal and multipotency. Accordingly, a population of cells called “side population” (SP), which has been isolated from gliomas on the basis of their ability to extrude fluorescent dyes, behaves as stem cells and is resistant to chemotherapeutic treatments. This review will focus on the expression of the stem cell markers nestin and CD133 in glioma cancer stem cells. In addition, the possible role of Platelet Derived Growth Factor receptor type α (PDGFR-α) and Notch signalling in normal development and tumourigenesis of gliomas are also discussed. Future work elucidating the mechanisms that control normal development will help to identify new cancer stem cell-related genes. The identification of important markers and the elucidation of signalling pathways involved in survival, proliferation and differentiation of CSCs appear to be fundamental for developing an effective therapy of brain tumours. Special issue article in honor of Dr. Anna Maria Giuffrida-Stella.     

神经干细胞生物制剂治疗中枢神经系统恶性肿瘤的研究进展

中枢神经系统肿瘤是一类由于神经元、胶质细胞及神经系统中其它相关细胞异常增殖及恶性转化引发的、具有侵袭性的神经系统疾病。由于发病部位常危及控制机体重要功能的中枢,传统治疗方法对原发性神经系统肿瘤的治疗效果不佳,导致该类疾病患者的临床受益有限。因此,开发更为有效的治疗性药物是该领域亟待解决的重大科学问题。神经干细胞(NSCs)是一类具有自我更新和分化的神经系统来源的成体干细胞。已有大量研究报道,NSCs对神经系统来源的肿瘤具有特异的定向迁移及浸润能力,可以将具有肿瘤杀伤活性的药物定向传递到病灶部位。因此,这一特性使得NSCs成为一种具有良好临床转化潜力的生物治疗候选制剂,为中枢神经系统恶性肿瘤的新型药物研发提供了新思路。     

Establishing Embryonic Mouse Neural Stem Cell Culture Using the Neurosphere Assay

In mammalians, stem cells acts as a source of undifferentiated cells to maintain cell genesis and renewal in different tissues and organs during the life span of the animal. They can potentially replace cells that are lost in the aging process or in the process of injury and disease. The existence of neural stem cells (NSCs) was first described by Reynolds and Weiss (1992) in the adult mammalian central nervous system (CNS) using a novel serum‐free culture system, the neurosphere assay (NSA). Using this assay, it is also feasible to isolate and expand NSCs from different regions of the embryonic CNS. These in vitro expanded NSCs are multipotent and can give rise to the three major cell types of the CNS. While the NSA seems relatively simple to perform, attention to the procedures demonstrated here is required in order to achieve reliable and consistent results. This video practically demonstrates NSA to generate and expand NSCs from embryonic day 14-mouse brain tissue and provides technical details so one can achieve reproducible neurosphere cultures. The procedure includes harvesting E14 mouse embryos, brain microdissection to harvest the ganglionic eminences, dissociation of the harvested tissue in NSC medium to gain a single cell suspension, and finally plating cells in NSA culture. After 5-7 days in culture, the resulting primary neurospheres are passaged to further expand the number of the NSCs for future experiments.Download video file.^{(69M, mov)}     

Embryonic and adult neural stem cell research in China

Neural stem cells(NSCs) are one specific type of multipotential stem cells that have the ability to proliferate for a long time and to differentiate into neural cells,including neurons,astrocytes and oligodendrocytes.These NSCs exist in both the embryonic and adult central nervous system(CNS) of all mammalian species.Progress has been made in the understanding of the developmental regulation of NSCs and their function in neurogenesis.This review discusses recent progress in this area,with emphasis on work d...     

Stem cells act through multiple mechanisms to benefit mice with neurodegenerative metabolic disease

Intracranial transplantation of neural stem cells (NSCs) delayed disease onset, preserved motor function, reduced pathology and prolonged survival in a mouse model of Sandhoff disease, a lethal gangliosidosis. Although donor-derived neurons were electrophysiologically active within chimeric regions, the small degree of neuronal replacement alone could not account for the improvement. NSCs also increased brain beta-hexosaminidase levels, reduced ganglioside storage and diminished activated microgliosis. Additionally, when oral glycosphingolipid biosynthesis inhibitors (beta-hexosaminidase substrate inhibitors) were combined with NSC transplantation, substantial synergy resulted. Efficacy extended to human NSCs, both to those isolated directly from the central nervous system (CNS) and to those derived secondarily from embryonic stem cells. Appreciating that NSCs exhibit a broad repertoire of potentially therapeutic actions, of which neuronal replacement is but one, may help in formulating rational multimodal strategies for the treatment of neurodegenerative diseases.