Murine Neural Progenitor Cells Research Articles

P.1.g.037 - New insights on trazodone effect in promoting neuronal differentiation of adult murine hippocampal neural progenitor cells

P.1.g.037 - New insights on trazodone effect in promoting neuronal differentiation of adult murine hippocampal neural progenitor cells

Transfection of arginine decarboxylase gene increases the neuronal differentiation of neural progenitor cells

Growing evidence suggests that the clinical use of neural progenitor cells (NPCs) is hampered by heterogeneity, poor neuronal yield and low survival rate. Recently, we reported that retrovirus-delivered human arginine decarboxylase (hADC) genes improve cell survival against oxidative insult in murine NPCs in vitro. This study investigates whether the induced expression of hADC gene in mNPCs induces any significant change in the cell fate commitment. The evaluation of induced hADC gene function was assessed by knockdown of hADC gene using specific siRNA. The hADC gene delivery triggered higher expression of N-CAM, cell adhesion molecule and MAP-2, neuronal marker. However, the hADC gene knockdown showed downregulation of N-CAM and MAP-2 expression suggesting that hADC gene delivery favors cell fate commitment of mNPCs towards neuronal lineage. Neurite outgrowth was significantly longer in the hADC infected cells. The neurotrophic signal, BDNF aided in the neuronal commitment, differentiation, and maturation of hADC-mNPCs through PI3K and ERK1/2 activation. The induction of neuron-like differentiation is believed to be regulated by the expression of GSK-3β and Wnt/β-catenin signaling pathways. Our findings suggest that hADC gene delivery favors cell fate commitment of mNPCs towards neuronal lineage, bring new advances in the field of neurogenesis and cell therapy.

Bio-Orthogonally Crosslinked, Engineered Protein Hydrogels with Tunable Mechanics and Biochemistry for Cell Encapsulation.

Covalently-crosslinked hydrogels are commonly used as 3D matrices for cell culture and transplantation. However, the crosslinking chemistries used to prepare these gels generally cross-react with functional groups present on the cell surface, potentially leading to cytotoxicity and other undesired effects. Bio-orthogonal chemistries have been developed that do not react with biologically relevant functional groups, thereby preventing these undesirable side reactions. However, previously developed biomaterials using these chemistries still possess less than ideal properties for cell encapsulation, such as slow gelation kinetics and limited tuning of matrix mechanics and biochemistry. Here, engineered elastin-like proteins (ELPs) are developed that cross-link via strain-promoted azide-alkyne cycloaddition (SPAAC) or Staudinger ligation. The SPAAC-crosslinked materials form gels within seconds and complete gelation within minutes. These hydrogels support the encapsulation and phenotypic maintenance of human mesenchymal stem cells, human umbilical vein endothelial cells, and murine neural progenitor cells. SPAAC-ELP gels exhibit independent tuning of stiffness and cell adhesion, with significantly improved cell viability and spreading observed in materials containing a fibronectin-derived arginine-glycine-aspartic acid (RGD) domain. The crosslinking chemistry used permits further material functionalization, even in the presence of cells and serum. These hydrogels are anticipated to be useful in a wide range of applications, including therapeutic cell delivery and bioprinting.

Mifepristone-inducible transgene expression in neural progenitor cells in vitro and in vivo.

Numerous gene and cell therapy strategies are being developed for the treatment of neurodegenerative disorders. Many of these strategies use constitutive expression of therapeutic transgenic proteins, and although functional in animal models of disease, this method is less likely to provide adequate flexibility for delivering therapy to humans. Ligand-inducible gene expression systems may be more appropriate for these conditions, especially within the central nervous system (CNS). Mifepristone's ability to cross the blood-brain barrier makes it an especially attractive ligand for this purpose. We describe the production of a mifepristone-inducible vector system for regulated expression of transgenes within the CNS. Our inducible system used a lentivirus-based vector platform for the ex vivo production of mifepristone-inducible murine neural progenitor cells that express our transgenes of interest. These cells were processed through a series of selection steps to ensure that the cells exhibited appropriate transgene expression in a dose-dependent and temporally controlled manner with minimal background activity. Inducible cells were then transplanted into the brains of rodents, where they exhibited appropriate mifepristone-inducible expression. These studies detail a strategy for regulated expression in the CNS for use in the development of safe and efficient gene therapy for neurological disorders.

Possible activation by the green tea amino acid theanine of mammalian target of rapamycin signaling in undifferentiated neural progenitor cells in vitro

We have shown marked promotion of both proliferation and neuronal differentiation in pluripotent P19 cells exposed to the green tea amino acid theanine, which is a good substrate for SLC38A1 responsible for glutamine transport. In this study, we evaluated the activity of the mammalian target of rapamycin (mTOR) kinase pathway, which participates in protein translation, cell growth and autophagy in a manner relevant to intracellular glutamine levels, in murine neural progenitor cells exposed to theanine. Exposure to theanine promoted the phosphorylation of mTOR and downstream proteins in neurospheres from embryonic mouse neocortex. Although stable overexpression of SLC38A1 similarly facilitated phosphorylation of mTOR-relevant proteins in undifferentiated P19 cells, theanine failed to additionally accelerate the increased phosphorylation in these stable transfectants. Theanine accelerated the formation of neurospheres from murine embryonic neocortex and adult hippocampus, along with facilitation of both 5-bromo-2’-deoxyuridine incorporation and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide reduction in embryonic neurospheres. In embryonic neurospheres previously exposed to theanine, a significant increase was seen in the number of cells immunoreactive for a neuronal marker protein after spontaneous differentiation. These results suggest that theanine activates the mTOR signaling pathway for proliferation together with accelerated neurogenesis in murine undifferentiated neural progenitor cells.

Enhanced differentiation of neural progenitor cells into neurons of the mesencephalic dopaminergic subtype on topographical patterns

Parkinson's disease (PD) is a neurodegenerative disease attributed to the loss of midbrain dopaminergic (DA) neurons. The current lack of predictive models for this disease has been hampered by the acquirement of robust cells, posing a major barrier to drug development. Differentiation of stem cells into subtype specific cells may be guided by appropriate topographical cues but the role of topography has hitherto not been well understood. We used a Multi-Architecture (MARC) chip with various topographical structures and identified three topographies, which generate DA neurons from murine hippocampal neural progenitor cells with the highest percentage of neuronal (β-III-tubulin positive) and dopaminergic (tyrosine hydroxylase positive) populations. Analysis on single pattern structures showed that 2 μm gratings with 2 μm spacing and 2 μm height (2 μm gratings) and 2 μm gratings with hierarchical structure produced cells with the highest gene expression of TH and PITX3, with the longest neurite and highest percentage of alignment. Quantitative image analysis showed the 2 μm gratings produced cells with the highest expression of pituitary homeobox 3 (PITX3), LIM homeobox transcription factor 1 alpha (LMX1a), aldehyde dehydrogenase 1 family member A1 (ALDH1a1) and microtubule associated protein 2 (MAP2), as compared to nano-gratings and unpatterned controls. These patterns also enhance DA neuron differentiation on different substrate rigidities, as seen on both poly-dimethylsiloxane (PDMS) and tissue culture polystyrene (TCPS) substrates. These results show the use of topographical influence for neuronal subtype specification, which could be translated into a wide range of clinical applications for PD.

Ultrastructural analysis of murine hippocampal neural progenitor cells in culture.

Despite the great number of studies devoted to neural stem/progenitor cell biology, the ultrastructural characteristics of these cells in vitro have not been fully studied. To determine the fine structure of hippocampal neural progenitor cells (NPCs) in culture, mouse fetal hippocampi (E18) were extracted, dissected, and cells were expanded as adherent monolayer culture. Electron microscopy revealed that NPCs had an immature phenotype, with a high nuclear/cytoplasmic ratio, small and scant organelles, underdeveloped endoplasmic reticulum, and many free ribosomes and polysomes. Our results may contribute to a better understanding of the fine structure and physiology of hippocampal NPCs in vitro.

Abstract B59: Wild-type ALK and both ALK-R1275Q and ALK-F1174L activating mutations display a strong oncogenic activity in vivo in murine neural crest progenitor cells via cooperation with c-myc

Abstract Neuroblastoma (NB), a neural crest-derived embryonal tumor, is a heterogeneous childhood malignancy that often presents as an incurable disease. The anaplastic lymphoma receptor tyrosine kinase gene (ALK) was shown to be overexpressed, mutated or amplified in the majority of NB. The most common mutation, ALK-F1174L displayed an efficient transforming activity in vivo, and was shown in transgenic mouse models to drive NB formation and to cooperate with MYCN in the oncogenic process. In this project, we aimed at comparing the in vivo oncogenic potential of ALK-wt, with the two most frequent activating mutations ALK-F1174L (only present in sporadic NB), and ALK-R1275Q (present in familial and sporadic NB). Our strategy included the stable expression of ALK-wt and mutated variants into murine neural crest progenitor cells (JoMa1), which are the well-recognized NB progenitors. In vitro, only ALK-F1174L and ALK-R1275Q conferred an oncogenic potential to JoMa1 cells as measured by clonogenic assays. In contrast, in vivo experiments showed that JoMa1 cells expressing ALK-wt, as well as activating mutations ALK-R1275Q and ALK-F1174L rapidly produced highly aggressive tumors after subcutaneous or orthotopic (adrenal gland) implantations in nude mice. JoMa1-ALK-F1174L cells induced the fastest tumor growth as compared to JoMa1-ALK-R1275Q and JoMa1-ALK-wt cells, revealing the tremendous tumorigenic potential of ALK-F1174L cells. Interestingly, as a result from ALK activation, orthotopic tumors or their derived cell lines strongly upregulated c-myc expression. Moreover, specific ALK inhibition using TAE684, or c-myc inhibition with 10058-F4, completely abrogated the in vitro clonogenic capacity of tumor-derived cell lines. Such observations suggest that the tumorigenic potential of neural crest progenitor cells is strongly dependent on both ALK and c-myc activity. Our study demonstrates for the first time an oncogenic activity of ALK-R1275Q and ALK-wt when overexpressed in neural crest cells, and reveals the complex interactions between ALK and the myc oncogene family in neural crest cell-derived tumor formation. Citation Format: Annick Mühlethaler-Mottet, Gisèle Montavon, Marjorie Flahaut, Nicolas Jauquier, Jean-Marc Joseph, Olivier Delattre, Lukas Sommer, Isabelle Janoueix-Lerosey, Nicole Gross. Wild-type ALK and both ALK-R1275Q and ALK-F1174L activating mutations display a strong oncogenic activity in vivo in murine neural crest progenitor cells via cooperation with c-myc. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr B59.

Abstract 1942: Lgl1 loss promotes stemness and invasion in EGFRvIII-driven gliomas

Abstract Stem and progenitor cells may divide asymmetrically to self-renew and produce differentiating progeny in a single division. Usually, during an asymmetric cell division (ACD), determinants of self-renewal and differentiation segregate to opposite daughter cells during mitosis and thereby specify distinct cell fates. Disruption of ACD is seen in many cancers with a stem or progenitor cell component, including malignant gliomas (Sugiarto et al., 2011, Cancer Cell 20:328-40). Yet, it is not clear whether this is a contributing factor or a consequence of neoplastic transformation. Lethal giant larvae 1 (Lgl1), a gene that was initially identified as a tumor suppressor in Drosophila, has been implicated in the asymmetric localization of cell fate determinants in neural progenitor cells (Klezovitch et al., 2004, Genes Dev 18:559-571). Here, we investigated the effects of Lgl1 depletion on distinct hallmarks of glioma. In murine neural progenitor cells carrying conditional null alleles of Lgl1 (Klezovitch et al., 2004, Genes Dev 18:559-571), depletion of Lgl1 resulted in reduced rates of ACD, increased expression of progenitor markers and impaired differentiation. In an orthotopic model of glioma, driven by expression of EGFRvIII, a frequent and constitutively active mutant form of epidermal growth factor receptor (EGFR), Lgl1 inactivation led to increased tumor invasiveness. Our data suggest that disruption of ACD in glioma precursor cells promotes maintenance of progenitor features and hampers differentiation. At later stages of gliomagenesis, loss of ACD and cell polarity controls may contribute to tumor invasiveness. Citation Format: Sandra Gomez-Lopez, Robin G. Lerner, Claudia Petritsch. Lgl1 loss promotes stemness and invasion in EGFRvIII-driven gliomas. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1942. doi:10.1158/1538-7445.AM2014-1942

Extending neurites sense the depth of the underlying topography during neuronal differentiation and contact guidance

The topography of the extracellular microenvironment influences cell morphology, provides conduct guidance and directs cell differentiation. Aspect ratio and dimension of topography have been shown to affect cell behaviours, but the ability and mechanism of depth-sensing is not clearly understood. We showed that murine neural progenitor cells (mNPCs) can sense the depth of the micro-gratings. Neurite elongation, alignment and neuronal differentiation were observed to increase with grating depth. We proposed a mechanism for depth-sensing by growing neurites: filopodial adhesion in the growth cones favour elongation but the bending rigidity of the neurite cytoskeleton resists it. Thus, perpendicular extension on deeper grooves is unfavourable as neurites need to bend over a larger angle. A quantitative model was developed and its prediction of neurite growth on gratings fit well with the experimental data. The results indicated that mNPC fate can be directed by appropriately designed patterned surfaces.

Wild-type ALK and activating ALK-R1275Q and ALK-F1174L mutations upregulate Myc and initiate tumor formation in murine neural crest progenitor cells.

The anaplastic lymphoma kinase (ALK) gene is overexpressed, mutated or amplified in most neuroblastoma (NB), a pediatric neural crest-derived embryonal tumor. The two most frequent mutations, ALK-F1174L and ALK-R1275Q, contribute to NB tumorigenesis in mouse models, and cooperate with MYCN in the oncogenic process. However, the precise role of activating ALK mutations or ALK-wt overexpression in NB tumor initiation needs further clarification. Human ALK-wt, ALK-F1174L, or ALK-R1275Q were stably expressed in murine neural crest progenitor cells (NCPC), MONC-1 or JoMa1, immortalized with v-Myc or Tamoxifen-inducible Myc-ERT, respectively. While orthotopic implantations of MONC- 1 parental cells in nude mice generated various tumor types, such as NB, osteo/ chondrosarcoma, and undifferentiated tumors, due to v-Myc oncogenic activity, MONC-1-ALK-F1174L cells only produced undifferentiated tumors. Furthermore, our data represent the first demonstration of ALK-wt transforming capacity, as ALK-wt expression in JoMa1 cells, likewise ALK-F1174L, or ALK-R1275Q, in absence of exogenous Myc-ERT activity, was sufficient to induce the formation of aggressive and undifferentiated neural crest cell-derived tumors, but not to drive NB development. Interestingly, JoMa1-ALK tumors and their derived cell lines upregulated Myc endogenous expression, resulting from ALK activation, and both ALK and Myc activities were necessary to confer tumorigenic properties on tumor-derived JoMa1 cells in vitro.

719. Mifepristone-Inducible Gene Expression of Target Genes in Murine and Human Neural Progenitor Cells

719. Mifepristone-Inducible Gene Expression of Target Genes in Murine and Human Neural Progenitor Cells

GSK3β, But Not GSK3α, Inhibits the Neuronal Differentiation of Neural Progenitor Cells As a Downstream Target of Mammalian Target of Rapamycin Complex1

Glycogen synthase kinase 3 (GSK3) acts as an important regulator during the proliferation and differentiation of neural progenitor cells (NPCs), but the roles of the isoforms of this molecule (GSK3α and GSK3β) have not been clearly defined. In this study, we investigated the functions of GSK3α and GSK3β in the context of neuronal differentiation of murine NPCs. Treatment of primary NPCs with a GSK3 inhibitor (SB216763) resulted in an increase in the percentage of TuJ1-positive immature neurons, suggesting an inhibitory role of GSK3 in embryonic neurogenesis. Downregulation of GSK3β expression increased the percentage of TuJ1-positive cells, while knock-down of GSK3α seemed to have no effect. When primary NPCs were engineered to stably express either isoform of GSK3 using retroviral vectors, GSK3β, but not GSK3α, inhibited neuronal differentiation and helped the cells to maintain the characteristics of NPCs. Mutant GSK3β (Y216F) failed to suppress neuronal differentiation, indicating that the kinase activity of GSK3β is important for this regulatory function. Similar results were obtained in vivo when a retroviral vector expressing GSK3β was delivered to E9.5 mouse brains using the ultrasound image-guided gene delivery technique. In addition, SB216763 was found to block the rapamycin-mediated inhibition of neuronal differentiation of NPCs. Taken together, our results demonstrate that GSK3β, but not GSK3α, negatively controls the neuronal differentiation of progenitor cells and that GSK3β may act downstream of the mammalian target of rapamycin complex1 signaling pathway.

P.1.023 Understanding epigenetic changes in CNS disorders: histone modification regulates LPS-induced inflammatory transcriptional response

were analyzed by mass spectrometry, functional protein association networks were analysed and candidate proteins were identified and prioritized. The resulting protein lists were curated using statistical and functional criteria to prioritize for the most significant Cntn6 interactor, which we name Interacting protein of Cntn6 (IPC6). To confirm the interaction of Cntn6 and IPC6, these studies were complemented with in vitro and in vivo coimmunoprecipitation experiments. Trans-membrane interaction of these proteins in the post-synapse was confirmed by subcellular fractionation experiments and cell-binding and -aggregation assays. Neuro-anatomical studies in mouse by immunohistochemistry and in situ hybridization confirmed co-expression of Cntn6 and IPC6 in the cortex and thalamus. Furthermore, the function of this interaction was demonstrated by morphological analysis of transfected murine neural progenitor cells. Based on these data we propose that Cntn6 participates in a synaptic proteininteraction network that engages several other established ASD genes. These studies provide a starting point for development and testing of novel pharmaceuticals that are able to restore appropriate synaptic function in ASD.

Organic Cation Transporter-Mediated Ergothioneine Uptake in Mouse Neural Progenitor Cells Suppresses Proliferation and Promotes Differentiation into Neurons

The aim of the present study is to clarify the functional expression and physiological role in neural progenitor cells (NPCs) of carnitine/organic cation transporter OCTN1/SLC22A4, which accepts the naturally occurring food-derived antioxidant ergothioneine (ERGO) as a substrate in vivo. Real-time PCR analysis revealed that mRNA expression of OCTN1 was much higher than that of other organic cation transporters in mouse cultured cortical NPCs. Immunocytochemical analysis showed colocalization of OCTN1 with the NPC marker nestin in cultured NPCs and mouse embryonic carcinoma P19 cells differentiated into neural progenitor-like cells (P19-NPCs). These cells exhibited time-dependent [3H]ERGO uptake. These results demonstrate that OCTN1 is functionally expressed in murine NPCs. Cultured NPCs and P19-NPCs formed neurospheres from clusters of proliferating cells in a culture time-dependent manner. Exposure of cultured NPCs to ERGO or other antioxidants (edaravone and ascorbic acid) led to a significant decrease in the area of neurospheres with concomitant elimination of intracellular reactive oxygen species. Transfection of P19-NPCs with small interfering RNA for OCTN1 markedly promoted formation of neurospheres with a concomitant decrease of [3H]ERGO uptake. On the other hand, exposure of cultured NPCs to ERGO markedly increased the number of cells immunoreactive for the neuronal marker βIII-tubulin, but decreased the number immunoreactive for the astroglial marker glial fibrillary acidic protein (GFAP), with concomitant up-regulation of neuronal differentiation activator gene Math1. Interestingly, edaravone and ascorbic acid did not affect such differentiation of NPCs, in contrast to the case of proliferation. Knockdown of OCTN1 increased the number of cells immunoreactive for GFAP, but decreased the number immunoreactive for βIII-tubulin, with concomitant down-regulation of Math1 in P19-NPCs. Thus, OCTN1-mediated uptake of ERGO in NPCs inhibits cellular proliferation via regulation of oxidative stress, and also promotes cellular differentiation by modulating the expression of basic helix-loop-helix transcription factors via an unidentified mechanism different from antioxidant action.

Exendin-4 Protects Neural Progenitor Cells from Glucolipoapoptosis

Type 2 diabetic and obese patients are under high risk to prematurely develop neurological complications such as stroke and Alzheimer’s disease. Interestingly, type 2-diabetes impairs adult neurogenesis in rodent animal models and this impairment has been suggested to play a role in the brain complications of this disease. Recent work from us and others showed that the treatment with the Glucagon-Like Peptide 1 Receptor (GLP-1R) agonist Exendin-4 stimulates adult neurogenesis in rodents. Based on these findings we have raised the hypothesis that Exendin-4 may counteract the detrimental effects induced by diabetes in neural stem/progenitor cells. The aim of this study was to investigate whether Exendin-4 protect neural progenitor cells from glucolipotoxicity and to analyse if the regulation of apoptosis may be involved in the Exendin-4 protecting effect. Murine neural progenitor cells were exposed to high palmitate and glucose, which characterize diabetic glucolipotoxicity, in presence/absence of Exendin-4. To determine whether neural progenitor cells proliferation was impacted by the Exendin-4 treatment, [3H] thymidine incorporation experiments were also performed. The expression of apoptosis key players, such as cleaved-caspase 3 and Bcl-2, were evaluated by western blotting. We show that Exendin-4 counteracts the impaired neural progenitor cell viability induced by glucolipotoxicity. Cell proliferation was not influenced by the Exendin-4 treatment. The protective effect induced by Exendin-4 correlated with decreased apoptosis. In addition, the Exendin-4 protective effect was completely abolished by using the GLP- 1R antagonist Ex-9-39, indicating that the protective effect by Exendin-4 was GLP-1R-mediated. In conclusion, we show a direct survival effect of GLP-1R activation on neural progenitor cells challenged by diabetic-like conditions. The results support a potential therapeutic role of GLP-1R agonists, based on neurogenesis stimulation, for the treatment of the neurological complications in Type 2-diabetes and obesity.

The cannabinoid CB2 receptor agonist AM1241 enhances neurogenesis in GFAP/Gp120 transgenic mice displaying deficits in neurogenesis

HIV-1 glycoprotein Gp120 induces apoptosis in rodent and human neurons in vitro and in vivo. HIV-1/Gp120 is involved in the pathogenesis of HIV-associated dementia (HAD) and inhibits proliferation of adult neural progenitor cells (NPCs) in glial fibrillary acidic protein (GFAP)/Gp120 transgenic (Tg) mice. As cannabinoids exert neuroprotective effects in several model systems, we examined the protective effects of the CB₂ receptor agonist AM1241 on Gp120-mediated insults on neurogenesis. We assessed the effects of AM1241 on survival and apoptosis in cultures of human and murine NPCs with immunohistochemical and TUNEL techniques. Neurogenesis in the hippocampus of GFAP/Gp120 transgenic mice in vivo was also assessed by immunohistochemistry. AM1241 inhibited in vitro Gp120-mediated neurotoxicity and apoptosis of primary human and murine NPCs and increased their survival. AM1241 also promoted differentiation of NPCs to neuronal cells. While GFAP/Gp120 Tg mice exhibited impaired neurogenesis, as indicated by reduction in BrdU⁺ cells and doublecortin⁺ (DCX⁺) cells, and a decrease in cells with proliferating cell nuclear antigen (PCNA), administration of AM1241 to GFAP/Gp120 Tg mice resulted in enhanced in vivo neurogenesis in the hippocampus as indicated by increase in neuroblasts, neuronal cells, BrdU⁺ cells and PCNA⁺ cells. Astrogliosis and gliogenesis were decreased in GFAP/Gp120 Tg mice treated with AM1241, compared with those treated with vehicle. The CB₂ receptor agonist rescued impaired neurogenesis caused by HIV-1/Gp120 insult. Thus, CB₂ receptor agonists may act as neuroprotective agents, restoring impaired neurogenesis in patients with HAD.

Phenotype and Stability of Neural Differentiation of Androgenetic Murine ES Cell-Derived Neural Progenitor Cells.

Uniparental zygotes with two paternal (androgenetic, AG) or two maternal genomes (gynogenetic, GG) cannot develop into viable offsprings but form blastocysts from which pluripotent embryonic stem (ES) cells can be derived. For most organs, it is unclear whether uniparental ES cells can give rise to stably expandable somatic stem cells that can repair injured tissues. Even if previous reports indicated that the capacity of AG ES cells to differentiate in vitro into pan-neural progenitor cells (pNPCs) and into cells expressing neural markers is similar to biparental [normal fertilized (N)] ES cells, their potential for functional neurogenesis is not known. Here we show that murine AG pNPCs give rise to neuron-like cells, which then generate sodium-driven action potentials while maintaining fidelity of imprinted gene expression. Neural engraftment after intracerebral transplantation was achieved only by late (22 days) AG and N pNPCs with in vitro low colony-forming cell (CFC) capacity. However, persisting CFC formation seen, in particular, in early (13 or 16 days) differentiation cultures of N and AG pNPCs correlated with a high incidence of trigerm layer teratomas. As AG ES cells display functional neurogenesis and in vivo stability similar to N ES cells, they represent a unique model system to study the roles of paternal and maternal genomes on neural development and on the development of imprinting-associated brain diseases.

Murine adult neural progenitor cells alter their proliferative behavior and gene expression after the activation of toll-like-receptor 3

Viral infections during pregnancy significantly increase the risk for psychological pathologies like schizophrenia in the offspring. One of the main morphological hallmarks of schizophrenia is a reduced size of the hippocampus. Since new neurons are produced in this particular brain compartment throughout life, it might be possible that low neurogenesis levels triggered by a maternal viral infection contribute to developmental deficits of the hippocampus. We injected polyinosinic:polycytidylic acid (Poly I:C) in pregnant C57Bl/6 mice to stimulate an anti-viral response through TLR3 and examined gene expressions in the neuronal progenitor cells (NPCs) of the offspring at different ages. Additionally, we treated adult NPC lines with Poly I:C to investigate its direct effect. We could show for the first time that TLR3 and its downstream effector molecule IRF3 are expressed in adult NPCs. Poly I:C treatment in vitro and in vivo led to the regulation of proliferation and genes involved in antiviral response, migration, and survival. These findings indicate that NPCs of the fetus are able to react towards an in utero immune response, and thus, changes in the neuronal stem cell pool can contribute to the development of neurological diseases like schizophrenia.

Microarray with Micro‐ and Nano‐topographies Enables Identification of the Optimal Topography for Directing the Differentiation of Primary Murine Neural Progenitor Cells

During development and tissue repair, progenitor cells are guided by both biochemical and biophysical cues of their microenvironment, including topographical signals. The topographical cues have been shown to play an important role in controlling the fate of cells. Systematic investigation of topographical structures with different geometries and sizes under the identical experimental conditions on the same chip will enhance the understanding of the role of shape and size in cell-topography interactions. A simple customizable multi-architecture chip (MARC) array is therefore developed to incorporate, on a single chip, distinct topographies of various architectural complexities, including both isotropic and anisotropic features, in nano- to micrometer dimensions, with different aspect ratios and hierarchical structures. Polydimethylsiloxane (PDMS) replicas of MARC are used to investigate the influence of different geometries and sizes in neural differentiation of primary murine neural progenitor cells (mNPCs). Anisotropic gratings (2 μm gratings, 250 nm gratings) and isotropic 1 μm pillars significantly promote differentiation of mNPCs into neurons, as indicated by expression of β-III-tubulin (59%, 58%, and 58%, respectively, compared to 30% on the control). In contrast, glial differentiation is enhanced on isotropic 2 μm holes and 1 μm pillars. These results illustrate that anisotropic topographies enhance neuronal differentiation while isotropic topographies enhance glial differentiation on the same chip under the same conditions. MARC enables simultaneous cost-effective investigation of multiple topographies, allowing efficient optimization of topographical and biochemical cues to modulate cell differentiation.