Neural Stem Cell Marker Nestin Research Articles

Multipotent nestin-expressing stem cells capable of forming neurons are located in the upper, middle and lower part of the vibrissa hair follicle

We have previously demonstrated that the neural stem-cell marker nestin is expressed in hair follicle stem cells. Nestin-expressing cells were initially identified in the hair follicle bulge area (BA) using a transgenic mouse model in which the nestin promoter drives the green fluorescent protein (ND-GFP). The hair-follicle ND-GFP-expressing cells are keratin 15-negative and CD34-positive and could differentiate to neurons, glia, keratinocytes, smooth muscle cells and melanocytes in vitro. Subsequently, we showed that the nestin-expressing stem cells could affect nerve and spinal cord regeneration after injection in mouse models. In the present study, we separated the mouse vibrissa hair follicle into three parts (upper, middle and lower). Each part of the follicle was cultured separately in DMEM-F12 containing B-27 and 1% methylcellulose supplemented with basic FGF. After 2 mo, the nestin-expressing cells from each of the separated parts of the hair follicle proliferated and formed spheres. Upon transfer of the spheres to RPMI 1640 medium containing 10% FBS, the nestin-expressing cells in the spheres differentiated to neurons, as well as glia, keratinocytes, smooth muscle cells and melanocytes. The differentiated cells were produced by spheres which formed from nestin-expressing cells from all segments of the hair follicle. However, the differentiation potential is greatest in the upper part of the follicle. This result is consistent with trafficking of nestin-expressing cells throughout the hair follicle from the bulge area to the dermal papilla that we previously observed. The nestin-expressing cells from the upper part of the follicle produced spheres in very large amounts, which in turn differentiated to neurons and other cell types. The results of the present study demonstrate that multipotent, nestin-expressing stem cells are present throughout the hair follicle and that the upper part of the follicle can produce the stem cells in large amounts that could be used for nerve and spinal cord repair.

Spatial Domains of Progenitor-Like Cells and Functional Complexity of a Stem Cell Niche in the Neonatal Rat Spinal Cord

During spinal cord development, progenitors in the neural tube are arranged within spatial domains that generate specific cell types. The ependyma of the postnatal spinal cord seems to retain cells with properties of the primitive neural stem cells, some of which are able to react to injury with active proliferation. However, the functional complexity and organization of this stem cell niche in mammals remains poorly understood. Here, we combined immunohistochemistry for cell-specific markers with patch-clamp recordings to test the hypothesis that the ependyma of the neonatal rat spinal cord contains progenitor-like cells functionally segregated within specific domains. Cells on the lateral aspects of the ependyma combined morphological and molecular traits of ependymocytes and radial glia (RG) expressing S100β and vimentin, displayed passive membrane properties and were electrically coupled via Cx43. Cells contacting the ventral and dorsal poles expressed the neural stem cell markers nestin and/or vimentin, had the typical morphology of RG, and appeared uncoupled displaying various combinations of K(+) and Ca(2+) voltage-gated currents. Although progenitor-like cells were mitotically active around the entire ependyma, the proliferative capacity seemed higher on lateral domains. Our findings represent the first evidence that the ependyma of the rat harbors progenitor-like cells with heterogeneous electrophysiological phenotypes organized in spatial domains. The manipulation of specific functional properties in the heterogeneous population of progenitor-like cells contacting the ependyma may in future help to regulate their behavior and lineage potential, providing the cell types required for the endogenous repair of the injured spinal cord.

Abstract 5343: Identification of brain tumor initiating cells using the stem cell marker aldehyde dehydrogenase 1

Abstract Aldehyde dehydrogenase 1 (ALDH1) has been identified in stem cells from both normal and cancerous tissue. This study aimed to evaluate the potential of ALDH1 as a universal brain tumor initiating cell (BTIC) marker applicable to primary brain tumors and their biological role in maintaining stem cell status. Cells from various primary brain tumors (24 pediatric and 6 adult brain tumors) were stained with Aldefluor and sorted by flow cytometry. We investigated the impact of ALDH1 expression on BTIC characteristics in vitro and on tumorigenic potential in vivo. Primary cultured brain tumor cells showed universal expression of ALDH1, with 0.3 to 28.9% of the cells in various tumors identified as ALDH1+. ALDH1+ cells generate neurospheres with high proliferative potential, express neural stem cell markers (nestin and musashi) and differentiate into multiple nervous system lineages. ALDH1+ cells are phenotypically distinct from CD133+ cells, and they show high expression of induced pluripotent stem cell-related genes. Notably, targeted knockdown of ALDH1 by shRNA interference in BTICs potently disturbed their self-renewing ability. After three months, ALDH1+ cells gave rise to tumors in 93% of mice whereas ALDH1- cells did not. The characteristic pathology of mice brain tumors from ALDH1+ cells was similar to that of human brain tumors, and these cells are highly proliferative in vivo. Our data suggest that primary brain tumors contain distinct subpopulations of cells that have high expression levels of ALDH1 and BTIC characteristics. ALDH1 might be a potential therapeutic target applicable to primary brain tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5343. doi:1538-7445.AM2012-5343

Long-term expansion of human foetal neural progenitors leads to reduced graft viability in the neonatal rat brain

We previously reported that early passage human foetal neural progenitors (hFNPs) survive long-term in the rodent host brain whereas late passage cells disappear at later post-graft survival times. The extent to which this finding is related to changes in the expanded FNPs or in the adult host brain environment was not determined. Here we report the effect of expanding hFNPs for different periods of time in vitro on their ability to survive transplantation into the neonatal rat hippocampus, a generally more permissive environment than the adult rat brain. After 2 and 8weeks in vitro, transplanted hFNPs formed large grafts, most of which survived well until at least 12weeks. However, following continued expansion, hFNPs formed smaller grafts, and cells transplanted after 20weeks expansion produced no surviving grafts, even at early survival times.To determine whether this could be due to a dilution of “true” neural stem cells through more differentiated progeny over time in culture, we derived homogeneous neural stem (NS) cells grown as a monolayer from the 8week expanded hFNPs. These cells homogeneously expressed the neural stem cell markers sox-2, 3CB2 and nestin and were expanded for 5months before transplantation into the neonatal rat brain. However, these cells exhibited a similar survival profile to the long-term expanded FNPs.These results indicate that, while the cellular phenotype of neural stem cells may appear to be stable in vitro using standard markers, expansion profoundly influences the ability of such cells to form viable grafts.

In Reply to Torsvik et al. “Spontaneous Transformation of Stem Cells In Vitro and the Issue of Cross-Contamination”

1. We have recently re-tested the STR fingerprinting data in our paper (Int J Biol Sci 2011; 7:892-901). DNA fingerprinting analysis was performed using genomic DNA from hsNSCs (passage 22); T1 cells (passages 150) and HeLa cells by GeneMapper ID v3.2 (Applied Biosystems, Foster City, CA) for human STR markers. There are two loci of heterozygosity CSF1PO (9, 10) and D3S1358 (15, 18) in T1 cells (passages 150) which are different from those seen in Hela (vWA: 16, 18) and (TPOX: 12). Other than that, the similarity between T1 and Hela was >86%, while the similarity between T1 and hsNSC was <14%. Overall, our recent data suggest that T1 cells may have cross-contaminated by HeLa cells. 2. We have also performed additional immunofluorescence assays to show the expression of neural stem cell markers on T1 and Hela cells. Consistent with our previous results, T1 cells expressed both nestin and CD133 (Fig.1A, B). However, HeLa cells were negative for these two markers (Fig. 1C, D). 3. In separate additional in vivo experiments we have recently completed, Hela and T1 cells were injected into the nude mice subcutaneously and intracranially, respectively. Two weeks later, subcutaneous xenografts were formed in HeLa cell-implanted mice (Fig. 1H). In contrast, T1 cells did not result in xenografts subcutaneously. This is consistent with our previous results we reported in the paper. On the other hand, intracranial neoplasias were found in T1 cell-implanted mice (Fig.1E) after 6 weeks. Immunofluorescence analysis suggested that these tumor cells expressed neural stem cell markers nestin and CD133 (Fig.1F, G). Approximately 10 days after HeLa cells were injected into the mice brain, all the animals died, but no obvious neoplasia was found. In summary, although the genome of T1 cells was apparently contaminated by HeLa cells; T1 cells are both phenotypically and tumorigenically different from HeLa cells. Ivyspring

Pericytes: A universal adult tissue stem cell?

In this issue of Cytometry part A, Montiel-Eulefi et al. describe a neurogenic cell population residing in the vascular wall of rat aortas. Although the authors did not characterize them in situ, these aorta-derived cells were shown to express well-known pericytic markers such as CD90, α-smooth muscle actin, and the platelet derived growth factor receptors α and β (1,2) after a short period in culture. The authors also report the native expression of the neural stem cell marker nestin (3), which in combination with the chondroitin sulfate proteoglycan NG2 marks both pericytes and neurogenic progenitors (1,3). They validated the neurogenic potential of cultured aorta-derived pericytes by showing the acquisition of mature neural marker expression and functional neural-like stimulus-response. In this study, the pluripotency associated marker stage-specific embryonic antigen 1 (SSEA-1) was detected on aorta-derived cultured pericytes only after induction of neuronal differentiation, in contrast to SSEA-1 expression by human microvascular pericytes, which has been reported to be constitutive (4). A variety of multilineage stem/progenitor cells have been described in the recent literature, most of them being identified retrospectively following primary culture. These include multipotent adult progenitor cells (5), mesenchymal stem cells (MSC) (6) and adipose-derived stem cells (ASC; Ref. 7). Most of these multipotent cell populations have been localized in vivo to a niche in the microvasculature wall, including MSC (8) and ASC (4,7), although MSC have been also isolated from larger vessels, both arteries (9) and veins (10). At the clonal level, the multilineage potential of MSC (and other comparable stem cell populations) has been demonstrated in vitro for mesenchymal lineages (adipogenic, osteogenic, chondrogenic, and either skeletal or smooth muscle potential; reviewed in Ref. 11). Further, trans-differentiation across germ layers has been reported by various groups, including differentiation toward neuronal lineages (reviewed in Ref. 11). During embryogenesis, MSC originate in two distinct waves, the first from the neural crest. A second wave appears to derive from the mesoderm (12). The relationship between MSC and pericytes in the adult is not immediately clear. In a variety of tissues, pericytes have been proposed to be the immediate progenitors of MSC (8). Brain microvascular pericytes have been previously shown to differentiate into multiple neuronal lineages (3), consistent with the observation that pericytes residing in the face and forebrain originate, like neurons, from the neural crest (13). In this work, the authors successfully differentiated aorta-derived pericytes toward the neurogenic lineage, suggesting that pericytes originating outside the neural crest can also be induced to differentiate down the neuronal lineage pathway. The constitutive coexpression of nestin and NG2 in tissue pericytes is consistent with neuronal-lineage priming, similar to that observed in mesenchymal lineages (6), and potentially explaining the cross-germ layer plasticity reported in the literature (11). Our own data, relating adipose pericytes, which associate with the microvasculature (7), to the mesenchymal-like supra-adventitial adipose stromal cells (SA-ASC), which surround small vessels in an annular fashion, support the interpretation that pericytes are the progenitors of MSC in the adult. Figure 1A shows a hypothetical differentiation scheme based on multiparameter flow cytometric analysis of the stromal vascular fraction of disaggregated adipose tissue. According to this scheme, CD146+, CD90±, CD34− pericytes differentiate from the inside out, giving rise to MSC-like CD146−, CD90+, CD34+ SA-ASC through a rare CD146+, CD90+, CD34+ transit amplifying cell of high proliferative capacity. The SA-ASC undergo spontaneous adipogenesis after reaching confluence in culture and presumably give rise to mature adi-pocytes in vivo. In keeping with the findings of Montiel-Eulefi et al. human adipose stromal vascular cells also occasionally give rise to CD146+ cells with neuronal morphology after two weeks in culture in the presence of EGM2 (Fig. 1B). CD 146 is not just a pericyte marker. In the neurobiology literature it is known as gicerin, a ligand for nerve outgrowth factor with an important role in neurite extension and synaptogenesis (14). Figure 1 (A) Differentiation scheme for pericytes, transit amplifying cells and supra-adventitial stem cells in adipose tissue. Flow cytometry was performed on 10 freshly isolated human adipose stromal vascular preparations according to previously published methods. ... Taken together, these data may help answer the conundrum posed by adult tissue stem cells: Does each tissue have its own oligopotent stem cell which arises during embryogenesis after lineage specification, or is there a universal pluripotent adult tissue stem cell which has escaped lineage restriction (15)? If the findings of Montiel-Eulefi et al., which even large vessels harbor pericytes capable of cross germ-layer differentiation, prove to be generalizable, then pericytes may represent something approaching the universal adult tissue stem cell, and the adventitia of large and small vessels may be their niche.

Role of laminin-111 in neurotrophin-3 production of canine adipose-derived stem cells: Involvement of Akt, mTOR, and p70S6K

Extracellular matrix (ECM) components play an important role in the regulation and maintenance of neural stem cells (NSCs). Laminin, an ECM component, is a key factor in promoting axonal regeneration and differentiation of NSCs. Since NSCs cannot be easily harvested with low morbidity, adipose-derived stem cells have been suggested for therapeutic applications of neural tissue damage. Therefore, the potential of laminin-111 to enhance the production of neurotrophin-3 (NT3) and its related signal pathways from canine adipose tissue-derived stem cells (cADSCs) was investigated. Laminin-111 enhanced NT3 production in neural induction medium (NIM). Treatment of NIM or laminin-111 on cADSCs distinctively changed integrin β1 mRNA and protein expression levels. In addition, laminin-111-induced Akt phosphorylation was inhibited by integrin β1 small interfering RNA (siRNA) and PI3K inhibitors (LY294002 and wortmannin). Furthermore, increased phosphorylations of mTOR and p70S6K by laminin-111 were blocked by inhibitors or specific siRNA, respectively. Moreover, laminin-111-induced NT3 production was blocked by these inhibitors. In experiments to induce the differentiation of cADSCs, laminin-111 increased the expression of neuronal markers β 3 tubulin, MAP2, and NeuN, and decreased the expression of the NSC markers nestin and vimentin. In conclusion, laminin-111 increases NT3 production through Akt, mTOR, and p70S6K pathways via integrin β1 in cADSCs cultured in NIM.

Vascular endothelial growth factor (VEGF) isoform regulation of early forebrain development

This work was designed to determine the role of the vascular endothelial growth factor A (VEGF) isoforms during early neuroepithelial development in the mammalian central nervous system (CNS), specifically in the forebrain. An emerging model of interdependence between neural and vascular systems includes VEGF, with its dual roles as a potent angiogenesis factor and neural regulator. Although a number of studies have implicated VEGF in CNS development, little is known about the role that the different VEGF isoforms play in early neurogenesis. We used a mouse model of disrupted VEGF isoform expression that eliminates the predominant brain isoform, VEGF164, and expresses only the diffusible form, VEGF120. We tested the hypothesis that VEGF164 plays a key role in controlling neural precursor populations in developing cortex. We used microarray analysis to compare gene expression differences between wild type and VEGF120 mice at E9.5, the primitive stem cell stage of the neuroepithelium. We quantified changes in PHH3-positive nuclei, neural stem cell markers (Pax6 and nestin) and the Tbr2-positive intermediate progenitors at E11.5 when the neural precursor population is expanding rapidly. Absence of VEGF164 (and VEGF188) leads to reduced proliferation without an apparent effect on the number of Tbr2-positive cells. There is a corresponding reduction in the number of mitotic spindles that are oriented parallel to the ventricular surface relative to those with a vertical or oblique angle. These results support a role for the VEGF isoforms in supporting the neural precursor population of the early neuroepithelium.

Soluble Amyloid Precursor Protein Induces Rapid Neural Differentiation of Human Embryonic Stem Cells

Human embryonic stem cells (hESCs) offer tremendous potential for not only treating neurological disorders but also for their ability to serve as vital reagents to model and investigate human disease. To further our understanding of a key protein involved in Alzheimer disease pathogenesis, we stably overexpressed amyloid precursor protein (APP) in hESCs. Remarkably, we found that APP overexpression in hESCs caused a rapid and robust differentiation of pluripotent stem cells toward a neural fate. Despite maintenance in standard hESC media, up to 80% of cells expressed the neural stem cell marker nestin, and 65% exhibited the more mature neural marker β-3 tubulin within just 5 days of passaging. To elucidate the mechanism underlying the effects of APP on neural differentiation, we examined the proteolysis of APP and performed both gain of function and loss of function experiments. Taken together, our results demonstrate that the N-terminal secreted soluble forms of APP (in particular sAPPβ) robustly drive neural differentiation of hESCs. Our findings not only reveal a novel and intriguing role for APP in neural lineage commitment but also identify a straightforward and rapid approach to generate large numbers of neurons from human embryonic stem cells. These novel APP-hESC lines represent a valuable tool to investigate the potential role of APP in development and neurodegeneration and allow for insights into physiological functions of this protein.

Dermis‐derived stem cells: a source of epidermal melanocytes and melanoma?

Human multipotent dermal stem cells (DSCs) have been isolated and propagated from the dermal region of neonatal foreskin. DSCs can self-renew, express the neural crest stem cell markers NGFRp75 and nestin, and are capable of differentiating into a wide variety of cell types including mesenchymal and neuronal lineages and melanocytes, indicative of their neural crest origin. When placed in the context of reconstructed skin, DSCs migrate to the basement membrane zone and differentiate into melanocytes. These findings, combined with the identification of NGFRp75-positive cells in the dermis of human foreskin, which are devoid of hair, suggest that DSCs may be a self-renewing source of extrafollicular epidermal melanocytes. In this review, we discuss the properties of DSCs, the pathways required for melanocyte differentiation, and the value of 3D reconstructed skin to assess the behavior and contribution of DSCs in the naturalized environment of human skin. Potentially, DSCs provide a link to malignant melanoma by being a target of UVA-induced transformation.

Long-term Cultured Human Neural Stem Cells Undergo Spontaneous Transformation to Tumor-Initiating Cells

In this report, we describe the spontaneous malignant transformation of long-term cultured human fetal striatum neural stem cells (hsNSCs, passage 17). After subcutaneous transplantation of long-term cultured hsNSCs into immunodeficient nude mice, 2 out of 15 mice formed xenografts which expressed neuroendocrine tumor markers CgA and NSE. T1 cells, a cell line that we derived from one of the two subcutaneous xenografts, have undergone continuous expansion in vitro. These T1 cells showed stem cell-like features and expressed neural stem cell markers nestin and CD133. The T1 cells were involved in abnormal karyotype, genomic instability and fast proliferation. Importantly, after long-term in vitro culture, the T1 cells did not result in subcutaneous xenografts, but induced intracranial tumor formation, indicating that they adjusted themselves to the intracranial microenvironment. We further found that the T1 cells exhibited an overexpressed level of EGFR, and the CD133 positive T1 cells showed a truncation mutation in the exons 2-7 of the EGFR (EGFRvIII) gene. These results suggest that continuous expansion of neural stem cells in culture may lead to malignant spontaneous transformation. This phenomenon may be functionally related to EGFR by EGFRvIII gene mutation.

Comparison of Human Muscle-Derived Stem Cells and Human Adipose-Derived Stem Cells in Neurogenic Trans-Differentiation

PurposeErectile dysfunction (ED) remains a major complication from cavernous nerve injury during radical prostatectomy. Recently, stem cell treatment for ED has been widely reported. This study was conducted to investigate the availability, differentiation into functional cells, and potential of human muscle-derived stem cells (hMDSCs) and human adipose-derived stem cells (hADSCs) for ED treatment.Materials and MethodsWe compared the neural differentiation of hMDSCs and hADSCs. Human muscle and adipose tissues were digested with collagenase, followed by filtering and centrifugation. For neural induction, isolated hMDSCs and hADSCs were incubated in neurobasal media containing forskolin, laminin, basic-fibroblast growth factor, and epidermal growth factor for 5 days. Following neural induction, hMDSCs and hADSCs were differentiated into neural cells, including neurons and glia, in vitro.ResultsIn neural differentiated hMDSCs (d-hMDSCs) and differentiated hADSCs (d-hADSCs), neural stem cell marker (nestin) showed a significant decrease by immunocytochemistry, and neuronal marker (β-tubulin III) and glial marker (GFAP) showed a significant increase, compared with primary hMDSCs and hADSCs. Real-time chain reaction analysis and Western blotting demonstrated significantly elevated levels of mRNA and protein of β-tubulin III and GFAP in d-hADSCs compared with d-hMDSCs.ConclusionsWe demonstrated that hMDSCs and hADSCs can be induced to undergo phenotypic and molecular changes consistent with neurons. The neural differentiation capacity of hADSCs was better than that of hMDSCs.

Alleviation of hyperglycemia in diabetic rats by intraportal injection of insulin-producing cells generated from surgically resected human pancreatic tissue

Although islet transplantation holds promise for the treatment of diabetes, the scarcity of donor tissue remains a major drawback. The aim of this study is to generate insulin-producing cells from adult human pancreatic cells isolated from surgically resected pancreatic tissue. To isolate pancreatic endocrine precursor cells from 57 surgically resected pancreases, the cells were cultured and propagated in conditioned medium after which they were differentiated in Matrigel. The resultant cells were characterized using morphology, immunofluorescent studies, expression of differentiated pancreatic islet-specific genes using quantitative reverse transcription-PCR, and glucose-induced insulin secretion through analysis of C-peptide secretion. The relationships between propagation of insulin-producing cells and clinical variables of the donor were also analyzed. Finally, insulin-producing cell function was examined in streptozotocin-induced diabetic rats. Pancreatic endocrine precursor cells were successfully cultured; insulin-producing cells cultured from soft pancreas parenchyma had a significantly higher success rate. Morphological examination revealed islet-like cluster formation upon transfer to Matrigel. The presence of the neural stem cell marker nestin, duct cell marker cytokeratin 19, and endocrine cell markers C-peptide and pancreatic and duodenal homeobox 1, was also observed. In addition, glucose-stimulated C-peptide release was significantly increased in the insulin-producing cells. Furthermore, in diabetic rats, transplantation of insulin-producing cells reduced hyperglycemia. Isolated pancreatic endocrine precursor cells from surgically resected pancreatic tissue differentiated into insulin-producing cells and showed characteristics of functional endocrine cells. Thus, surgically resected pancreatic tissue may represent an alternative source of functional insulin-producing cells.

Folic Acid Remodels Chromatin on Hes1 and Neurog2 Promoters during Caudal Neural Tube Development

The mechanism(s) behind folate rescue of neural tube closure are not well understood. In this study we show that maternal intake of folate prior to conception reverses the proliferation potential of neural crest stem cells in homozygous Splotch embryos (Sp(-/-)) via epigenetic mechanisms. It is also shown that the pattern of differentiation seen in these cells is similar to wild-type (WT). Cells from open caudal neural tubes of Sp(-/-) embryos exhibit increased H3K27 methylation and decreased expression of KDM6B possibly due to up-regulation of KDM6B targeting micro-RNAs such as miR-138, miR-148a, miR-185, and miR-339-5p. In our model, folate reversed these epigenetic marks in folate-rescued Sp(-/-) embryos. Using tissue from caudal neural tubes of murine embryos we also examined H3K27me2 and KDM6B association with Hes1 and Neurog2 promoters at embryonic day E10.5, the proliferative stage, and E12.5, when neural differentiation begins. In Sp(-/-) embryos compared with WT, levels of H3K27me2 associated with the Hes1 promoter were increased at E10.5, and levels associated with the Neurog2 promoter were increased at E12.5. KDM6B association with Hes1 and Neurog2 promoters was inversely related to H3K27me2 levels. These epigenetic changes were reversed in folate-rescued Sp(-/-) embryos. Thus, one of the mechanisms by which folate may rescue the Sp(-/-) phenotype is by increasing the expression of KDM6B, which in turn decreases H3K27 methylation marks on Hes1 and Neurog2 promoters thereby affecting gene transcription.

The advantages of hair follicle pluripotent stem cells over embryonic stem cells and induced pluripotent stem cells for regenerative medicine

Multipotent adult stem cells have many potential therapeutic applications. Our recent findings suggest that hair follicles are a promising source of easily accessible multipotent stem cells. Stem cells in the hair follicle area express the neural stem cell marker nestin, suggesting that hair-follicle stem cells and neural stem cells have common features. Nestin-expressing hair follicle stem cells can form neurons and other cell types, and thus adult hair follicle stem cells could have important therapeutic applications, particularly for neurologic diseases. Transplanted hair follicle stem cells promote the functional recovery of injured peripheral nerve and spinal cord. Recent findings suggest that direct transplantation of hair-follicle stem cells without culture can promote nerve repair, which makes them potentially clinically practical. Human hair follicle stem cells as well as mouse hair follicle stem cells promote nerve repair and can be applied to test the hypothesis that human hair follicle stem cells can provide a readily available source of neurologically therapeutic stem cells. The use of hair follicle stem cells for nerve regeneration overcomes critical problems of embryonic stem cells or induced pluripotent stem cells in that the hair follicle stem cells are multipotent, readily accessible, non-oncogenic, and are not associated with ethical issues.

Increased Levels of FoxA1 Transcription Factor in Pluripotent P19 Embryonal Carcinoma Cells Stimulate Neural Differentiation

Transcription factor FoxA1 plays a critical role during embryonic development and is activated during retinoic acid (RA)-induced neural differentiation of pluripotent P19 embryonal carcinoma cells at the early stage, which is marked by decreased expression of Nanog and increased expression of neural stem cell marker Nestin. To further understand how FoxA1 mediates neural differentiation, we have overexpressed FoxA1 through an adenovirus vector in P19 cells and identified that early neurogenesis-related sonic hedgehog (Shh) gene is activated directly by FoxA1. Knockdown of FoxA1 expression during P19 cell neural differentiation results in prevention of Shh and Nestin induction. FoxA1 binds to Shh promoter at -486 to -462 bp region and activates the promoter in cotransfection assays. Furthermore, overexpression of FoxA1 alone in P19 cells stimulates expression of Nestin and results in decreased protein levels of Nanog. During RA-induced P19 cell differentiation, elevated levels of FoxA1 increase the population of neurons, evidenced by stimulated expression of neuron-specific Neurofilament-1 and Tubulin betaIII. Together, our results suggest a critical involvement of FoxA1 in stimulating neural differentiation of pluripotent stem cells at early stages.

Nestin is expressed in HMB‐45 negative melanoma cells in dermal parts of nodular melanoma

Nestin, a marker of neural stem cells, is expressed in the stem cells of the mouse hair follicle. The nestin-expressing hair follicle stem cells can differentiate into neurons, glia, keratocytes, smooth muscle cells and melanocytes in vitro. These pluripotent nestin-expressing stem cells are keratin 15 (K15)-negative, suggesting that they are in a relatively undifferentiated state. Recent studies suggest that the epithelial stem cells are important in tumorigenesis, and nestin expression is thought to be important in tumorigenesis. In the present study, we examined the expression of the hair follicle and neural stem cell marker nestin, as well as S-100 and HMB-45, in melanoma. Nestin immunoreactivity was observed in the HMB-45-negative melanoma cells in all five cases of amelanotic nodular melanomas. Moreover, nestin immunoreactivity was observed in the dermal parts in seven of 10 cases of melanotic nodular melanomas. Especially, nestin immunoreactivity was observed in the HMB-45-negative melanoma cells in the dermal parts of all 10 cases of HMB-45-negative amelanotic and melanotic nodular melanomas. On the other hand, nestin expression was negative in 10 of 12 cases of superficial spreading melanoma. These results suggest that nestin is an important marker of HMB-45-negative melanoma cells in the dermal parts of patients with nodular melanoma.

Longterm quiescent cells in the aged human subventricular neurogenic system specifically express GFAP‐δ

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-delta). To further define the phenotype of these GFAP-delta 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-delta was expressed in the SVZ along the ventricle, in the RMS and in the OB. The GFAP-delta 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-delta positive cells in the SVZ. In the RMS, GFAP-delta was expressed in the glial net surrounding the neuroblasts. In the OB, GFAP-delta positive cells co-expressed PCNA. We also showed that GFAP-delta 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-delta is expressed in an astrocytic subpopulation in the SVZ, the RMS and the OB. Importantly, we provide the first evidence that GFAP-delta is specifically expressed in longterm quiescent cells in the human SVZ, which are reminiscent of NSCs.

Functional neural differentiation of human adipose tissue-derived stem cells using bFGF and forskolin

BackgroundAdult mesenchymal stem cells (MSCs) derived from adipose tissue have the capacity to differentiate into mesenchymal as well as endodermal and ectodermal cell lineage in vitro. We characterized the multipotent ability of human adipose tissue-derived stem cells (hADSCs) as MSCs and investigated the neural differentiation potential of these cells.ResultsHuman ADSCs from earlobe fat maintained self-renewing capacity and differentiated into adipocytes, osteoblasts, or chondrocytes under specific culture conditions. Following neural induction with bFGF and forskolin, hADSCs were differentiated into various types of neural cells including neurons and glia in vitro. In neural differentiated-hADSCs (NI-hADSCs), the immunoreactivities for neural stem cell marker (nestin), neuronal markers (Tuj1, MAP2, NFL, NFM, NFH, NSE, and NeuN), astrocyte marker (GFAP), and oligodendrocyte marker (CNPase) were significantly increased than in the primary hADSCs. RT-PCR analysis demonstrated that the mRNA levels encoding for ABCG2, nestin, Tuj1, MAP2, NFL, NFM, NSE, GAP43, SNAP25, GFAP, and CNPase were also highly increased in NI-hADSCs. Moreover, NI-hADSCs acquired neuron-like functions characterized by the display of voltage-dependent tetrodotoxin (TTX)-sensitive sodium currents, outward potassium currents, and prominent negative resting membrane potentials under whole-cell patch clamp recordings. Further examination by RT-PCR showed that NI-hADSCs expressed high level of ionic channel genes for sodium (SCN5A), potassium (MaxiK, Kv4.2, and EAG2), and calcium channels (CACNA1C and CACNA1G), which were expressed constitutively in the primary hADSCs. In addition, we demonstrated that Kv4.3 and Eag1, potassium channel genes, and NE-Na, a TTX-sensitive sodium channel gene, were highly induced following neural differentiation.ConclusionsThese combined results indicate that hADSCs have the same self-renewing capacity and multipotency as stem cells, and can be differentiated into functional neurons using bFGF and forskolin.

A Hierarchy of Self-Renewing Tumor-Initiating Cell Types in Glioblastoma

The neural stem cell marker CD133 is reported to identify cells within glioblastoma (GBM) that can initiate neurosphere growth and tumor formation; however, instances of CD133(-) cells exhibiting similar properties have also been reported. Here, we show that some PTEN-deficient GBM tumors produce a series of CD133(+) and CD133(-) self-renewing tumor-initiating cell types and provide evidence that these cell types constitute a lineage hierarchy. Our results show that the capacities for self-renewal and tumor initiation in GBM need not be restricted to a uniform population of stemlike cells, but can be shared by a lineage of self-renewing cell types expressing a range of markers of forebrain lineage.