Development Of Neural Stem Cells Research Articles

Expression of a SOX1 overlapping transcript in neural differentiation and cancer models

ABSTRACTSOX1 is a member of the SOXB1 subgroup of transcription factors involved in early embryogenesis, CNS development and maintenance of neural stem cells. The structure and regulation of the human SOX1 locus has been less studied than that of SOX2, another member of the SOXB1 subgroup for which an overlapping transcript has been reported. Here we report that the SOX1 locus harbours a SOX1 overlapping transcript (SOX1-OT), and describe expression, splicing variants and detection of SOX1-OT in different stem and cancer cells. RT-PCR and RACE experiments were performed to detect and characterise the structure of SOX1-OT in neuroprogenitor cultures and across different cancer cell lines. SOX1-OT was found to present a complex structure including several unannotated exons, different transcript variants and at least two potential transcription start sites. SOX1-OT was found to be highly expressed in differentiated neural stem cells across different time points of differentiation, and its expression correlated with SOX1 gene expression. Concomitant expression of SOX1 and SOX1-OT was further observed in several cancer cell models. While the function of this transcript is unknown, the regulatory role reported for other lncRNAs strongly suggests a possible role for SOX1-OT in regulating SOX1 expression, as previously observed for SOX2. The elucidation of the genetic and regulatory context governing SOX1 expression will contribute to clarifying its role in stem cell differentiation and tumorigenesis.

Human Neural Stem Cell Therapy for Chronic Ischemic Stroke: Charting Progress from Laboratory to Patients.

Chronic disability after stroke represents a major unmet neurologic need. ReNeuron's development of a human neural stem cell (hNSC) therapy for chronic disability after stroke is progressing through early clinical studies. A Phase I trial has recently been published, showing no safety concerns and some promising signs of efficacy. A single-arm Phase II multicenter trial in patients with stable upper-limb paresis has recently completed recruitment. The hNSCs administrated are from a manufactured, conditionally immortalized hNSC line (ReNeuron's CTX0E03 or CTX), generated with c-mycERTAM technology. This technology has enabled CTX to be manufactured at large scale under cGMP conditions, ensuring sufficient supply to meets the demands of research, clinical development, and, eventually, the market. CTX has key pro-angiogenic, pro-neurogenic, and immunomodulatory characteristics that are mechanistically important in functional recovery poststroke. This review covers the progress of CTX cell therapy from its laboratory origins to the clinic, concluding with a look into the late stage clinical future.

Cardiotrophin-1 stimulates the neural differentiation of human umbilical cord blood-derived mesenchymal stem cells and survival of differentiated cells through PI3K/Akt-dependent signaling pathways.

Cardiotrophin-1 (CT1) plays an important role in the differentiation, development, and survival of neural stem cells. In this study, we analyzed its effects on the stimulation of human umbilical cord blood-derived mesenchymal stem cells in terms of their potential to differentiate into neuron-like cells, their survival characteristics, and the molecular mechanisms involved. The treatment of cells with neural induction medium (NIM) and CT1 generated more cells that were neuron-like and produced stronger expression of neural-lineage markers than cells treated with NIM and without CT1. Bcl-2 and Akt phosphorylation (p-Akt) expression levels increased significantly in cells treated with both NIM and CT1. This treatment also effectively blocked cell death following neural induction and decreased Bax, Bak and cleaved-caspase 3 expression compared with cells treated with NIM without CT1. In addition, the inhibition of phosphatidylinositol 3-kinase (PI3K) abrogated p-Akt and Bcl-2 expression. Thus, PI3K/Akt contribute to CT1-stimulated neural differentiation and to the survival of differentiated cells.

MiR-1297 regulates neural stem cell differentiation and viability through controlling Hes1 expression.

Neural stem cells (NSCs) are self-renewing, undifferentiated and multipotent precursors that can generate neuronal and glial lineages. MicroRNAs (miRNAs) are small non-coding RNAs that act crucial roles in cell proliferation, differentiation and migration. However, the role of miR-1297 in the development of NSCs is still unknown. Primary NSCs were isolated from rat's embryos. The expression of miR-1297 and Hes1 were measured by qRT-PCR. Western blot was performed to detect the protein expression of Hes1, β-tubulin-III and GFAP. We showed that miR-1297 expression was upregulated during NSC differentiation, while the expression of Hes1 was decreased during NSC differentiation. Elevated expression of miR-1297 promoted the NSCs viability and increased the formation of NSCs to neurospheres. Ecoptic expression of miR-1297 promoted β-tubulin-III expression in the NSCs. Overexpression of miR-1297 decreased GFAP expression in the NSCs. Furthermore, we demonstrated that miR-1297 regulated NSCs viability and differentiation by directly targeting Hes1. Overexpression of miR-1297 suppressed Hes1 expression in the NSCs. These results suggested that miR-1297 played an important role in NSCs viability and differentiation through inhibiting Hes1 expression.

Neural stem cell transplantation in ischemic stroke: A role for preconditioning and cellular engineering

Ischemic stroke continues to be a leading cause of morbidity and mortality throughout the world. To protect and/or repair the ischemic brain, a multitiered approach may be centered on neural stem cell (NSC) transplantation. Transplanted NSCs exert beneficial effects not only via structural replacement, but also via immunomodulatory and/or neurotrophic actions. Unfortunately, the clinical translation of such promising therapies remains elusive, in part due to their limited persistence/survivability within the hostile ischemic microenvironment. Herein, we discuss current approaches for the development of NSCs more amenable to survival within the ischemic brain as a tool for future cellular therapies in stroke.

Accumulated quiescent neural stem cells in adult hippocampus of the mouse model for the MECP2 duplication syndrome

Duplications of Methyl CpG binding protein 2 (MECP2) -containing segments lead to the MECP2 duplication syndrome, in which severe autistic symptoms were identified. Whether adult neurogenesis may play a role in pathogenesis of autism and the role of MECP2 on state determination of adult neural stem cells (NSCs) remain largely unclear. Using a MECP2 transgenic (TG) mouse model for the MECP2 duplication syndrome, we found that adult hippocampal quiescent NSCs were significantly accumulated in TG mice comparing to wild type (WT) mice, the neural progenitor cells (NPCs) were reduced and the neuroblasts were increased in adult hippocampi of MECP2 TG mice. Interestingly, we found that parvalbumin (PV) positive interneurons were significantly decreased in MECP2 TG mice, which were critical for determining fates of adult hippocampal NSCs between the quiescence and activation. In summary, we found that MeCP2 plays a critical role in regulating fate determination of adult NSCs. These evidences further suggest that abnormal development of NSCs may play a role in the pathogenesis of the MECP2 duplication syndrome.

The Crossroads of Neural Stem Cell Development and Tumorigenesis.

Isolated brain tumors contain cells that exhibit stem cell features and a tissue microenvironment bearing remarkable similarities to the normal neurogenic niche. This supports the idea that neural stem (NSCs) or progenitor cells, and their progeny are the likely tumor cell(s) of origin. This prompted the investigation of the relationship between NSCs/progenitors and the initiation of tumorigenesis. These studies led to the identification of common signaling machineries underlying NSC development and tumor formation, particularly those with known roles in proliferation and cell fate determination. This review will explore the molecular mechanisms that regulate NSC behavior in the neurogenic niche of the forebrain, and how deregulation of the developmental potential of NSCs might contribute to tumorigenesis.

Effect of propofol on microRNA expression in rat primary embryonic neural stem cells.

BackgroundPropofol is a widely used intravenous anesthetic that is well-known for its protective effect in various human and animal disease models. However, the effects of propofol on neurogenesis, especially on the development of neural stem cells (NSCs), remains unknown. Related microRNAs may act as important regulators in this process.MethodsPublished Gene Expression Omnibus (GEO) DataSets related to propofol were selected and re-analyzed to screen neural development-related genes and predict microRNA (miRNA) expression using bioinformatic methods. Screening of the genes and miRNAs was then validated by qRT-PCR analysis of propofol-treated primary embryonic NSCs.ResultsFour differentially expressed mRNAs were identified in the screen and 19 miRNAs were predicted based on a published GEO DataSet. Two of four mRNAs and four of 19 predicted miRNAs were validated by qRT-PCR analysis of propofol-treated NSCs. Rno-miR-19a (Rno, Rattus Norvegicus) and rno-miR-137, and their target gene EGR2, as well as rno-miR-19b-2 and rno-miR-214 and their target gene ARC were found to be closely related to neural developmental processes, including proliferation, differentiation, and maturation of NSCs.ConclusionPropofol influences miRNA expression; however, further studies are required to elucidate the mechanism underlying the effects of propofol on the four miRNAs and their target genes identified in this study. In particular, the influence of propofol on the entire development process of NSCs remains to be clarified.Electronic supplementary materialThe online version of this article (doi:10.1186/s12871-016-0259-1) contains supplementary material, which is available to authorized users.

BLOS2 negatively regulates Notch signaling during neural and hematopoietic stem and progenitor cell development.

Notch signaling plays a crucial role in controling the proliferation and differentiation of stem and progenitor cells during embryogenesis or organogenesis, but its regulation is incompletely understood. BLOS2, encoded by the Bloc1s2 gene, is a shared subunit of two lysosomal trafficking complexes, biogenesis of lysosome-related organelles complex-1 (BLOC-1) and BLOC-1-related complex (BORC). Bloc1s2-/- mice were embryonic lethal and exhibited defects in cortical development and hematopoiesis. Loss of BLOS2 resulted in elevated Notch signaling, which consequently increased the proliferation of neural progenitor cells and inhibited neuronal differentiation in cortices. Likewise, ablation of bloc1s2 in zebrafish or mice led to increased hematopoietic stem and progenitor cell production in the aorta-gonad-mesonephros region. BLOS2 physically interacted with Notch1 in endo-lysosomal trafficking of Notch1. Our findings suggest that BLOS2 is a novel negative player in regulating Notch signaling through lysosomal trafficking to control multiple stem and progenitor cell homeostasis in vertebrates.

Accelerating bioelectric functional development of neural stem cells by graphene coupling: Implications for neural interfacing with conductive materials

In order to govern cell-specific behaviors in tissue engineering for neural repair and regeneration, a better understanding of material-cell interactions, especially the bioelectric functions, is extremely important. Graphene has been reported to be a potential candidate for use as a scaffold and neural interfacing material. However, the bioelectric evolvement of cell membranes on these conductive graphene substrates remains largely uninvestigated. In this study, we used a neural stem cell (NSC) model to explore the possible changes in membrane bioelectric properties - including resting membrane potentials and action potentials - and cell behaviors on graphene films under both proliferation and differentiation conditions. We used a combination of single-cell electrophysiological recordings and traditional cell biology techniques. Graphene did not affect the basic membrane electrical parameters (capacitance and input resistance), but resting membrane potentials of cells on graphene substrates were more strongly negative under both proliferation and differentiation conditions. Also, NSCs and their progeny on graphene substrates exhibited increased firing of action potentials during development compared to controls. However, graphene only slightly affected the electric characterizations of mature NSC progeny. The modulation of passive and active bioelectric properties on the graphene substrate was accompanied by enhanced NSC differentiation. Furthermore, spine density, synapse proteins expressions and synaptic activity were all increased in graphene group. Modeling of the electric field on conductive graphene substrates suggests that the electric field produced by the electronegative cell membrane is much higher on graphene substrates than that on control, and this might explain the observed changes of bioelectric development by graphene coupling. Our results indicate that graphene is able to accelerate NSC maturation during development, especially with regard to bioelectric evolvement. Our findings provide a fundamental understanding of the role of conductive materials in tuning the membrane bioelectric properties in a graphene model and pave the way for future studies on the development of methods and materials for manipulating membrane properties in a controllable way for NSC-based therapies.

Treatment of multiple sclerosis by transplantation of neural stem cells derived from induced pluripotent stem cells.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS), with focal T lymphocytic infiltration and damage of myelin and axons. The underlying mechanism of pathogenesis remains unclear and there are currently no effective treatments. The development of neural stem cell (NSC) transplantation provides a promising strategy to treat neurodegenerative disease. However, the limited availability of NSCs prevents their application in neural disease therapy. In this study, we generated NSCs from induced pluripotent stem cells (iPSCs) and transplanted these cells into mice with experimental autoimmune encephalomyelitis (EAE), a model of MS. The results showed that transplantation of iPSC-derived NSCs dramatically reduced T cell infiltration and ameliorated white matter damage in the treated EAE mice. Correspondingly, the disease symptom score was greatly decreased, and motor ability was dramatically rescued in the iPSC-NSC-treated EAE mice, indicating the effectiveness of using iPSC-NSCs to treat MS. Our study provides pre-clinical evidence to support the feasibility of treating MS by transplantation of iPSC-derived NSCs.

Polo Kinase Phosphorylates Miro to Control ER-Mitochondria Contact Sites and Mitochondrial Ca2+ Homeostasis in Neural Stem Cell Development

Mitochondria play central roles in buffering intracellular Ca²⁺ transients. While basal mitochondrial Ca²⁺ (Ca²⁺ mito) is needed to maintain organellar physiology, Ca²⁺ mito overload can lead to cell death. How Ca²⁺ mito homeostasis is regulated is not well understood. Here we show that Miro, a known component of the mitochondrial transport machinery, regulates Drosophila neural stem cell (NSC) development through Ca²⁺ mito homeostasis control, independent of its role in mitochondrial transport. Miro interacts with Ca²⁺ transporters at the ER-mitochondria contact site (ERMCS). Its inactivation causes Ca²⁺ mito depletion and metabolic impairment, whereas its overexpression results in Ca²⁺ mito overload, mitochondrial morphology change, and apoptotic response. Both conditions impaired NSC lineage progression. Ca²⁺ mito homeostasis is influenced by Polo-mediated phosphorylation of a conserved residue in Miro, which positively regulates Miro localization to, and the integrity of, ERMCS. Our results elucidate a regulatory mechanism underlying Ca²⁺ mito homeostasis and how its dysregulation may affect NSC metabolism/development and contribute to disease.

Recent Evidence of the Regulatory Role of PPARs in Neural Stem Cells and Their Underlying Mechanisms for Neuroprotective Effects.

In recent years, beneficial effects of various ligands of three peroxisome-proliferator-activated receptor (PPAR) isoforms (α, β, γ) have been reported in neurodegenerative diseases through delaying the onset and progression of diseases, reducing lesion size and improving functional recovery. Neural stem cells (NSCs) are assumed as a promising strategy for the treatment of human neurodegenerative diseases. PPARs are supposed to be one group of the key regulators of fate decisions in neural stem cells during development and adulthood, through their impact on the target genes involving cell proliferation, death and differentiation. The neuroprotective role of PPARs is suggested to be closely associated with the inflammation control and regenerative function of NSCs. Nevertheless, the molecular mechanisms remain to be elucidated. Here, we review the current knowledge about the beneficial role of PPARs in NSC development and neurogenesis and attempt to discuss the underlying mechanisms.

Metformin Acts on Two Different Molecular Pathways to Enhance Adult Neural Precursor Proliferation/Self-Renewal and Differentiation.

SummaryThe recruitment of endogenous adult neural stem cells for brain repair is a promising regenerative therapeutic strategy. This strategy involves stimulation of multiple stages of adult neural stem cell development, including proliferation, self-renewal, and differentiation. Currently, there is a lack of a single therapeutic approach that can act on these multiple stages of adult neural stem cell development to enhance neural regeneration. Here we show that metformin, an FDA-approved diabetes drug, promotes proliferation, self-renewal, and differentiation of adult neural precursors (NPCs). Specifically, we show that metformin enhances adult NPC proliferation and self-renewal dependent upon the p53 family member and transcription factor TAp73, while it promotes neuronal differentiation of these cells by activating the AMPK-aPKC-CBP pathway. Thus, metformin represents an optimal candidate neuro-regenerative agent that is capable of not only expanding the adult NPC population but also subsequently driving them toward neuronal differentiation by activating two distinct molecular pathways.

MiR-381 Regulates Neural Stem Cell Proliferation and Differentiation via Regulating Hes1 Expression.

Neural stem cells are self-renewing, multipotent and undifferentiated precursors that retain the capacity for differentiation into both glial (astrocytes and oligodendrocytes) and neuronal lineages. Neural stem cells offer cell-based therapies for neurological disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease and spinal cord injuries. However, their cellular behavior is poorly understood. MicroRNAs (miRNAs) are a class of small noncoding RNAs involved in cell development, proliferation and differentiation through regulating gene expression at post-transcriptional level. The role of miR–381 in the development of neural stem cells remains unknown. In this study, we showed that overexpression of miR–381 promoted neural stem cells proliferation. It induced the neural stem cells differentiation to neurons and inhibited their differentiation to astrocytes. Furthermore, we identified HES1 as a direct target of miR–381 in neural stem cells. Moreover, re-expression of HES1 impaired miR-381-induced promotion of neural stem cells proliferation and induce neural stem cells differentiation to neurons. In conclusion, miR–381 played important role in neural stem cells proliferation and differentiation.

Control of the Normal and Pathological Development of Neural Stem and Progenitor Cells by the PC3/Tis21/Btg2 and Btg1 Genes.

The PC3/Tis21/Btg2 and Btg1 genes are transcriptional cofactors belonging to the Btg/Tob family, which regulate the development of several cell types, including neural precursors. We summarize here the actions of these genes on neural precursors in the adult neurogenic niches and the cognitive defects associated when their expression is altered. We consider also recent findings implicating them in neural and non-neural tumors, since common developmental mechanisms are involved. PC3/Tis21 is required for the regulation of the maturation of stem and progenitor cells in the adult dentate gyrus and subventricular zone (SVZ), by controlling both their exit from the cell cycle and the ensuing terminal differentiation. Such actions are effected by regulating the expression of several genes, including cyclin D1, BMP4, Id3. In cerebellar precursors, however, PC3/Tis21 regulates chiefly their migration rather than proliferation or differentiation, with important implications for the onset of medulloblastoma, the cerebellar tumor. In fact PC3/Tis21 is a medulloblastoma-suppressor, as its overexpression in cerebellar precursors inhibits this tumor; PC3/Tis21 shows anti-tumor activity also in non-neural tumors. Btg1 presents a different functional profile, as it controls proliferation in adult stem/progenitor cells of dentate gyrus and SVZ, where is required to maintain their self-renewal and quiescence, but is apparently devoid of a direct control of their terminal differentiation or migration. Notably, physical exercise in Btg1-null mice rescues the loss of proliferative capability occurring in older stem cells. Both genes could be further investigated as therapeutical targets, namely, Btg1 in the process of aging and PC3/Tis21 as a tumor-suppressor.

Multiple facets of histone variant H2AX: a DNA double-strand-break marker with several biological functions.

In the last decade, many papers highlighted that the histone variant H2AX and its phosphorylation on Ser 139 (γH2AX) cannot be simply considered a specific DNA double-strand-break (DSB) marker with a role restricted to the DNA damage response, but rather as a ‘protagonist’ in different scenarios. This review will present and discuss an up-to-date view regarding the ‘non-canonical’ H2AX roles, focusing in particular on possible functional and structural parts in contexts different from the canonical DNA DSB response. We will present aspects concerning sex chromosome inactivation in male germ cells, X inactivation in female somatic cells and mitosis, but will also focus on the more recent studies regarding embryonic and neural stem cell development, asymmetric sister chromosome segregation in stem cells and cellular senescence maintenance. We will discuss whether in these new contexts there might be a relation with the canonical DNA DSB signalling function that could justify γH2AX formation. The authors will emphasize that, just as H2AX phosphorylation signals chromatin alteration and serves the canonical function of recruiting DSB repair factors, so the modification of H2AX in contexts other than the DNA damage response may contribute towards creating a specific chromatin structure frame allowing ‘non-canonical’ functions to be carried out in different cell types.

Exposure to acoustic stimuli promotes the development and differentiation of neural stem cells from the cochlear nuclei through the clusterin pathway.

Stem cell therapy has attracted widespread attention for a number of diseases. Recently, neural stem cells (NSCs) from the cochlear nuclei have been identified, indicating a potential direction for the treatment of sensorineural hearing loss. Acoustic stimuli play an important role in the development of the auditory system. In this study, we aimed to determine whether acoustic stimuli induce NSC development and differentiation through the upregulation of clusterin (CLU) in NSCs isolated from the cochlear nuclei. To further clarify the underlying mechanisms involved in the development and differentiation of NSCs exposed to acoustic stimuli, we successfully constructed animal models in which was CLU silenced by an intraperitoneal injection of shRNA targeting CLI. As expected, the NSCs from rats treated with LV-CLU shRNA exhibited a lower proliferation ratio when exposed to an augmented acoustic environment (AAE). Furthermore, the inhibition of cell apoptosis induced by exposure to AAE was abrogated after silencing the expression of the CLU gene. During the differentiation of acoustic stimuli-exposed stem cells into neurons, the number of astrocytes was significantly reduced, as evidenced by the expression of the cell markers, microtubule associated protein-2 (MAP-2) and glial fibrillary acidic protein (GFAP), which was markedly inhibited when the CLU gene was silenced. Our results indicate that acoustic stimuli may induce the development and differentiation of NSCs from the cochlear nucleus mainly through the CLU pathway. Our study suggests that CLU may be a novel target for the treatment of sensorineural hearing loss.

In Vitro Derivation of Melanocytes from Embryonic Neural Crest Stem Cells.

During development, melanocyte progenitors originate from the neural crest, a transient embryonic structure in vertebrates that gives rise to a variety of cell types including neurons and glia of the peripheral nervous system, smooth muscle cells of the cardiovascular system, chondrocytes and osteoblasts of the craniofacial elements, and pigment cells in the skin. In this chapter, we describe a method for the differentiation of multipotent embryonic neural crest stem cells into differentiated pigmented melanocytes by using in vitro explant culture system. This protocol allows the dissection of genetic and cellular mechanisms regulating neural crest stem cell and melanocyte development. Based on this knowledge it is possible to make predictions about processes that might also be implicated in melanoma initiation and progression.

Notch signaling and ageing.

Notch signaling is a master controller of the neural stem cell and neural development maintaining a significant role in the normal brain function. Notch genes are involved in embryogenesis, nervous system, and cardiovascular and endocrine function. On the other side, there are studies representing the involvement of Notch mutations in sporadic Alzheimer disease, other neurodegenerative diseases such as Down syndrome, Pick's and Prion's disease, and CADASIL. This manuscript attempts to present a holistic view of the positive or negative contribution of Notch signaling in the adult brain, and at the same time to present and promote the promising research fields of study.