Yap1 acts downstream of α-catenin to control epidermal proliferation.

During development and regeneration, proliferation of tissue-specific stem cells is tightly controlled to produce organs of a predetermined size. The molecular determinants of this process remain poorly understood. Here, we investigate the function of Yap1, the transcriptional effector of the Hippo signaling pathway, in skin biology. Using gain- and loss-of-function studies, we show that Yap1 is a critical modulator of epidermal stem cell proliferation and tissue expansion. Yap1 mediates this effect through interaction with TEAD transcription factors. Additionally, our studies reveal that α-catenin, a molecule previously implicated in tumor suppression and cell density sensing in the skin, is an upstream negative regulator of Yap1. α-catenin controls Yap1 activity and phosphorylation by modulating its interaction with 14-3-3 and the PP2A phosphatase. Together, these data identify Yap1 as a determinant of the proliferative capacity of epidermal stem cells and as an important effector of a "crowd control" molecular circuitry in mammalian skin.

Comprehensive Cell Surface Antigen Analysis Identifies Transferrin Receptor Protein-1 (CD71) as a Negative Selection Marker for Human Neuronal Cells.

Cell state-, developmental stage-, and lineage-specific combinatorial expression of cluster of differentiation (CD) molecules enables the identification of cellular subsets via multicolor flow cytometry. We describe an exhaustive characterization of neural cell types by surface antigens, exploiting human pluripotent stem cell-derived neural cell systems. Using multiwell screening approaches followed by detailed validation of expression patterns and dynamics, we exemplify a strategy for resolving cellular heterogeneity in stem cell paradigms. In addition to providing a catalog of surface antigens expressed in the neural lineage, we identified the transferrin receptor-1 (CD71) to be differentially expressed in neural stem cells and differentiated neurons. In this context, we describe a role for N-Myc proto-oncogene (MYCN) in maintaining CD71 expression in proliferating neural cells. We report that in vitro human stem cell-derived neurons lack CD71 surface expression and that the observed differential expression can be used to identify and enrich CD71- neuronal derivatives from heterogeneous cultures. Stem Cells 2019;37:1293-1306.

The CD24 surface antigen in neural development and disease.

A cell's surface molecular signature enables its reciprocal interactions with the associated microenvironments in development, tissue homeostasis and pathological processes. The CD24 surface antigen (heat-stable antigen, nectadrin; small cell lung cancer antigen cluster-4) represents a prime example of a neural surface molecule that has long been known, but whose diverse molecular functions in intercellular communication we have only begun to unravel. Here, we briefly summarize the molecular fundamentals of CD24 structure and provide a comprehensive review of CD24 expression and functional studies in mammalian neural developmental systems and disease models (rodent, human). Striving for an integrated view of the intracellular signaling processes involved, we discuss the most pertinent routes of CD24-mediated signaling pathways and functional networks in neurobiology (neural migration, neurite extension, neurogenesis) and pathology (tumorigenesis, multiple sclerosis).

Neural deletion of Tgfbr2 impairs angiogenesis through an altered secretome.

Simultaneous generation of neural cells and that of the nutrient-supplying vasculature during brain development is called neurovascular coupling. We report on a transgenic mouse with impaired transforming growth factor ß (TGFß)-signalling in forebrain-derived neural cells using a Foxg1-cre knock-in to drive the conditional knock-out of the Tgfbr2. Although the expression of FOXG1 is assigned to neural progenitors and neurons of the telencephalon, Foxg1(cre/+);Tgfbr2(flox/flox) (Tgfbr2-cKO) mutants displayed intracerebral haemorrhage. Blood vessels exhibited an atypical, clustered appearance were less in number and displayed reduced branching. Vascular endothelial growth factor (VEGF) A, insulin-like growth factor (IGF) 1, IGF2, TGFß, inhibitor of DNA binding (ID) 1, thrombospondin (THBS) 2, and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 1 were altered in either expression levels or tissue distribution. Accordingly, human umbilical vein endothelial cells (HUVEC) displayed branching defects after stimulation with conditioned medium (CM) that was derived from primary neural cultures of the ventral and dorsal telencephalon of Tgfbr2-cKO. Supplementing CM of Tgfbr2-cKO with VEGFA rescued these defects, but application of TGFß aggravated them. HUVEC showed reduced migration towards CM of mutants compared with controls. Supplementing the CM with growth factors VEGFA, fibroblast growth factor (FGF) 2 and IGF1 partially restored HUVEC migration. In contrast, TGFß supplementation further impaired migration of HUVEC. We observed differences along the dorso-ventral axis of the telencephalon with regard to the impact of these factors on the phenotype. Together these data establish a TGFBR2-dependent molecular crosstalk between neural and endothelial cells during brain vessel development. These findings will be useful to further elucidate neurovascular interaction in general and to understand pathologies of the blood vessel system such as intracerebral haemorrhages, hereditary haemorrhagic telangiectasia, Alzheimers disease, cerebral amyloid angiopathy or tumour biology.

Off-Label Use of an External Hand Fixator for Craniomaxillofacial Fractures-An Anatomical Feasibility Study.

BACKGROUND: The lack of resources limits the treatment of craniomaxillofacial fractures (CMF) in low-income countries (LIC). Therefore, Barton bandages and/or interdental wiring are considered in these regions. Fracture reduction is maintained by permanent occlusion for 6 weeks, which often leads to limited compliance and dissatisfying results. The aim of this cadaver-based study is to evaluate the feasibility of the use of an external face fixator (EFF) for the treatment of CMF, its biomechanical values and to define the optimal pin insertion points and angles. MATERIALS AND METHODS: An AO hand fixator was used. CMF of types Le Fort 1-3 with split fractures of the hard palate were treated with EFF on 13 anatomical specimens. Fractures were created using a chisel, and pins were placed in specific anatomical regions. The maximal pull-out force [N] of pins was analysed by a tensile force gauge, and Fmax of the mandibular pins was evaluated. Computer tomography scans were performed on the healthy, fractured and EFF-treated skulls. RESULTS: The pull-out forces for the single pins were mandibular pins (n = 15, median 488.0 N), supraorbital pins (n = 15, median 455.0 N), zygomatic pins (n = 14, median 269.1 N), medial hard palate pins (n = 12, median 208.4 N) and lateral hard palate pins (n = 8, median 49.6 N). CONCLUSIONS: The results indicate that the operation technique is feasible, and the stability of the EFF is sufficient for maintaining the reduction. The required pins can safely be inserted into the described areas with good reduction results. Using EFF offers a feasible alternative to the non-surgical treatment of CMF in LIC.

Verteporfin-induced proteotoxicity impairs cell homeostasis and survival in neuroblastoma subtypes independent of YAP/TAZ expression.

Neuroblastoma (NB) is a highly aggressive extracranial solid tumor in children. Due to its heterogeneity, NB remains a therapeutic challenge. Several oncogenic factors, including the Hippo effectors YAP/TAZ, are associated with NB tumorigenesis. Verteporfin (VPF) is an FDA-approved drug shown to directly inhibit YAP/TAZ activity. Our study aimed to investigate VPF's potential as a therapeutic agent in NB. We show that VPF selectively and efficiently impairs the viability of YAP/TAZ-expressing NB GI-ME-N and SK-N-AS cells, but not of non-malignant fibroblasts. To investigate whether VPF-mediated NB cell killing is YAP-dependent, we tested VPF potency in CRISPR-mediated YAP/TAZ knock-out GI-ME-N cells, and BE(2)-M17 NB cells (a MYCN-amplified, predominantly YAP-negative NB subtype). Our data shows that VPF-mediated NB cell killing is not dependent on YAP expression. Moreover, we determined that the formation of higher molecular weight (HMW) complexes is an early and shared VPF-induced cytotoxic mechanism in both YAP-positive and YAP-negative NB models. The accumulation of HMW complexes, involving STAT3, GM130 and COX IV proteins, impaired cell homeostasis and triggered cell stress and cell death mechanisms. Altogether, our study shows significant in vitro and in vivo VPF-induced suppression of NB growth, making VPF a potential therapeutic candidate against NB.

Generation of iPSCs from cultured human malignant cells.

Induced pluripotent stem cells (iPSCs) can be generated from various differentiated cell types by the expression of a set of defined transcription factors. So far, iPSCs have been generated from primary cells, but it is unclear whether human cancer cell lines can be reprogrammed. Here we describe the generation and characterization of iPSCs derived from human chronic myeloid leukemia cells. We show that, despite the presence of oncogenic mutations, these cells acquired pluripotency by the expression of 4 transcription factors and underwent differentiation into cell types derived of all 3 germ layers during teratoma formation. Interestingly, although the parental cell line was strictly dependent on continuous signaling of the BCR-ABL oncogene, also termed oncogene addiction, reprogrammed cells lost this dependency and became resistant to the BCR-ABL inhibitor imatinib. This finding indicates that the therapeutic agent imatinib targets cells in a specific epigenetic differentiated cell state, and this may contribute to its inability to fully eradicate disease in chronic myeloid leukemia patients.

Glycan Epitope and Integrin Expression Dynamics Characterize Neural Crest Epithelial-to-Mesenchymal Transition (EMT) in Human Pluripotent Stem Cell Differentiation.

The neural crest gives rise to progeny as diverse as peripheral neurons, myelinating cells, cranial muscle, bone and cartilage tissues, and melanocytes. Neural crest derivation encompasses complex morphological change, including epithelial-to-mesenchymal transition (EMT) and migration to the eventual target locations throughout the body. Neural crest cultures derived from stem cells provide an attractive source for developmental studies in human model systems, of immediate biomedical relevance for neurocristopathies, neural cancer biology and regenerative medicine, if only appropriate markers for lineage and cell type definition and quality control criteria were available. Implementing a defined, scalable protocol to generate neural crest cells from embryonic stem cells, we identify stage-defining cluster-of-differentiation (CD) surface markers during human neural crest development in vitro. Acquisition of increasingly mesenchymal phenotype was characterized by absence of neuroepithelial stemness markers (CD15, CD133, CD49f) and by decrease of CD57 and CD24. Increased per-cell-expression of CD29, CD44 and CD73 correlated with established EMT markers as determined by immunofluorescence and immunoblot analysis. The further development towards migratory neural crest was associated with decreased CD24, CD49f (ITGA6) and CD57 (HNK1) versus an enhanced CD49d (ITGA4), CD49e (ITGA5) and CD51/CD61 (ITGAV/ITGB3) expression. Notably, a shift from CD57 to CD51/CD61 was identified as a sensitive surrogate surface indicator of EMT in neural crest in vitro development. The reported changes in glycan epitope and integrin surface expression may prove useful for elucidating neural crest stemness, EMT progression and malignancies.

Transcriptomic Landscape and Functional Characterization of Human Induced Pluripotent Stem Cell-Derived Limbal Epithelial Progenitor Cells.

Limbal stem cell deficiency (LSCD) is a complex, multifactorial disease affecting limbal epithelial progenitor cells (LEPC), which are essential for maintaining corneal stability and transparency. Human induced pluripotent stem cell-derived (hiPSC-) LEPC are a promising cell source for the treatment of LSCD. However, their similarity to native tissue-derived (T-) LEPC and their functional characterization has not been studied in detail. Here, we show that hiPSC-LEPC and T-LEPC have rather similar gene expression patterns, colony-forming ability, wound-healing capacity, and melanosome uptake. In addition, hiPSC-LEPC exhibited lower immunogenicity and reduced the proliferation of peripheral blood mononuclear cells compared with T-LEPC. Similarly, the hiPSC-LEPC secretome reduced the proliferation of vascular endothelial cells more than the T-LEPC secretome. Moreover, hiPSC-LEPC successfully repopulated decellularized human corneolimbal (DHC/L) scaffolds with multilayered epithelium, while basal deposition of fibrillary material was observed. These findings suggest that hiPSC-LEPC exhibited functional properties close to native LEPC and that hiPSC-LEPC-DHC/L scaffolds might be feasible for transplantation in patients suffering from LSCD in the future. Although hiPSC-LEPC-based stem cell therapy is promising, the current study also revealed new challenges, such as abnormal extracellular matrix deposition, that need to be overcome before hiPSC-LEPC-based stem cell therapies are viable.

Neurons derived from reprogrammed fibroblasts functionally integrate into the fetal brain and improve symptoms of rats with Parkinson's disease.

The long-term goal of nuclear transfer or alternative reprogramming approaches is to create patient-specific donor cells for transplantation therapy, avoiding immunorejection, a major complication in current transplantation medicine. It was recently shown that the four transcription factors Oct4, Sox2, Klf4, and c-Myc induce pluripotency in mouse fibroblasts. However, the therapeutic potential of induced pluripotent stem (iPS) cells for neural cell replacement strategies remained unexplored. Here, we show that iPS cells can be efficiently differentiated into neural precursor cells, giving rise to neuronal and glial cell types in culture. Upon transplantation into the fetal mouse brain, the cells migrate into various brain regions and differentiate into glia and neurons, including glutamatergic, GABAergic, and catecholaminergic subtypes. Electrophysiological recordings and morphological analysis demonstrated that the grafted neurons had mature neuronal activity and were functionally integrated in the host brain. Furthermore, iPS cells were induced to differentiate into dopamine neurons of midbrain character and were able to improve behavior in a rat model of Parkinson's disease upon transplantation into the adult brain. We minimized the risk of tumor formation from the grafted cells by separating contaminating pluripotent cells and committed neural cells using fluorescence-activated cell sorting. Our results demonstrate the therapeutic potential of directly reprogrammed fibroblasts for neuronal cell replacement in the animal model.

CD15, CD24, and CD29 define a surface biomarker code for neural lineage differentiation of stem cells.

Identification and use of cell surface cluster of differentiation (CD) biomarkers have enabled much scientific and clinical progress. We identify a CD surface antigen code for the neural lineage based on combinatorial flow cytometric analysis of three distinct populations derived from human embryonic stem cells: (1) CD15(+)/CD29(HI)/CD24(LO) surface antigen expression defined neural stem cells; (2) CD15(-)/CD29(HI)/CD24(LO) revealed neural crest-like and mesenchymal phenotypes; and (3) CD15(-)/CD29(LO)/CD24(HI) selected neuroblasts and neurons. Fluorescence-activated cell sorting (FACS) for the CD15(-)/CD29(LO)/CD24(HI) profile reduced proliferative cell types in human embryonic stem cell differentiation. This eliminated tumor formation in vivo, resulting in pure neuronal grafts. In conclusion, combinatorial CD15/CD24/CD29 marker profiles define neural lineage development of neural stem cell, neural crest, and neuronal populations from human stem cells. We believe this set of biomarkers enables analysis and selection of neural cell types for developmental studies and pharmacological and therapeutic applications.

Embryonic stem cell-derived Pitx3-enhanced green fluorescent protein midbrain dopamine neurons survive enrichment by fluorescence-activated cell sorting and function in an animal model of Parkinson's disease.

Both fetal ventral mesencephalic (VM) and embryonic stem (ES) cell-derived dopamine neurons have been used successfully to correct behavioral responses in animal models of Parkinson's disease. However, grafts derived from fetal VM cells or from ES cells contain multiple cell types, and the majority of these cells are not dopamine neurons. Isolation of ES cell-derived dopamine neurons and subsequent transplantation would both elucidate the capacity of these neurons to provide functional input and also further explore an efficient and safer use of ES cells for the treatment of Parkinson's disease. Toward this goal, we used a Pitx3-enhanced green fluorescent protein (Pitx3-eGFP) knock-in mouse blastocyst-derived embryonic stem (mES) cell line and fluorescence-activated cell sorting (FACS) to select and purify midbrain dopamine neurons. Initially, the dopaminergic marker profile of intact Pitx3-eGFP mES cultures was evaluated after differentiation in vitro. eGFP expression overlapped closely with that of Pitx3, Nurr1, Engrailed-1, Lmx1a, tyrosine hydroxylase (TH), l-aromatic amino acid decarboxylase (AADC), and vesicular monoamine transporter 2 (VMAT2), demonstrating that these cells were of a midbrain dopamine neuron character. Furthermore, postmitotic Pitx3-eGFP(+) dopamine neurons, which constituted 2%-5% of all live cells in the culture after dissociation, could be highly enriched to >90% purity by FACS, and these isolated neurons were viable, extended neurites, and maintained a dopaminergic profile in vitro. Transplantation to 6-hydroxydopamine-lesioned rats showed that an enriched dopaminergic population could survive and restore both amphetamine- and apomorphine-induced functions, and the grafts contained large numbers of midbrain dopamine neurons, which innervated the host striatum. Disclosure of potential conflicts of interest is found at the end of this article.

Molecular and cellular determinants for generating ES-cell derived dopamine neurons for cell therapy.

Embryonic stem (ES) cells can generate midbrain dopaminergic (DA) neuronal phenotypes in vitro and have been successfully applied to restore function in animal models of Parkinson's disease (PD). How can we best integrate our growinginsight into the regulatory cascade of transcription factors guiding midbrain specification to further improve the in vitro differentiation of midbrain DA neurons for cell therapy of PD? To characterize the differentiation of authentic DA neurons in vitro, expression patterns of the numerous midbrain-characteristic markers need to be investigated. When using forced gene expression, such factors have to be closely monitored to avoid generation of nonphysiological cell types. Fluorescent markers such as Pitx3-GFP, TH-GFP, Sox1-GFP or surface antigens have proven useful for elimination of unwanted cell types by cell sorting, thereby averting tumors and increasing the DA fraction for transplantation studies. The importance of appropriate timing during application of extrinsic factors and the influence of cell-cell interactions in the dish has to be taken into account. This conceptual synopsis outlines current objectives, progress, but also challenges, in deriving midbrain DA neurons from pluripotent stem cells for clinical and scientific applications.

Phytochrome-Based Extracellular Matrix with Reversibly Tunable Mechanical Properties.

Interrogation and control of cellular fate and function using optogenetics is providing revolutionary insights into biology. Optogenetic control of cells is achieved by coupling genetically encoded photoreceptors to cellular effectors and enables unprecedented spatiotemporal control of signaling processes. Here, a fast and reversibly switchable photoreceptor is used to tune the mechanical properties of polymer materials in a fully reversible, wavelength-specific, and dose- and space-controlled manner. By integrating engineered cyanobacterial phytochrome 1 into a poly(ethylene glycol) matrix, hydrogel materials responsive to light in the cell-compatible red/far-red spectrum are synthesized. These materials are applied to study in human mesenchymal stem cells how different mechanosignaling pathways respond to changing mechanical environments and to control the migration of primary immune cells in 3D. This optogenetics-inspired matrix allows fundamental questions of how cells react to dynamic mechanical environments to be addressed. Further, remote control of such matrices can create new opportunities for tissue engineering or provide a basis for optically stimulated drug depots.

Markers and methods for cell sorting of human embryonic stem cell-derived neural cell populations.

Neural cells differentiated in vitro from human embryonic stem cells (hESC) exhibit broad cellular heterogeneity with respect to developmental stage and lineage specification. Here, we describe standard conditions for the use and discovery of markers for analysis and cell selection of hESC undergoing neuronal differentiation. To generate better-defined cell populations, we established a working protocol for sorting heterogeneous hESC-derived neural cell populations by fluorescence-activated cell sorting (FACS). Using genetically labeled synapsin-green fluorescent protein-positive hESC-derived neurons as a proof of principle, we enriched viable differentiated neurons by FACS. Cell sorting methodology using surface markers was developed, and a comprehensive profiling of surface antigens was obtained for immature embryonic stem cell types (such as stage-specific embryonic antigen [SSEA]-3, -4, TRA-1-81, TRA-1-60), neural stem and precursor cells (such as CD133, SSEA-1 [CD15], A2B5, forebrain surface embryonic antigen-1, CD29, CD146, p75 [CD271]), and differentiated neurons (such as CD24 or neural cell adhesion molecule [NCAM; CD56]). At later stages of neural differentiation, NCAM (CD56) was used to isolate hESC-derived neurons by FACS. Such FACS-sorted hESC-derived neurons survived in vivo after transplantation into rodent brain. These results and concepts provide (a) a feasible approach for experimental cell sorting of differentiated neurons, (b) an initial survey of surface antigens present during neural differentiation of hESC, and (c) a framework for developing cell selection strategies for neural cell-based therapies.

Immature and neurally differentiated mouse embryonic stem cells do not express a functional Fas/Fas ligand system.

The potential of pluripotent embryonic stem (ES) cells to develop into functional cells or tissue provides an opportunity in the development of new therapies for many diseases including neurodegenerative disorders. The survival of implanted cells usually requires systemic immunosuppression, however, which severely compromises the host immune system, leading to complications in clinical transplantation. An optimal therapy would therefore be the induction of specific tolerance to the donor cells, while otherwise preserving functional immune responses. Fas ligand (FasL) is expressed in activated lymphocytes as well as cells in "immune-privileged" sites including the central nervous system. Its receptor, Fas, is expressed on various immune-reactive cell types, such as activated natural killer and T cells, monocytes, and polymorphic mononucleocytes, which can undergo apoptosis upon interaction with FasL. To render transplanted cells tolerant to host cellular immune responses, we genetically engineered mouse ES cells to express rat FasL (rFasL). The rFasL-expressing ES cells were analyzed for survival during in vitro neurodifferentiation and after transplantation to the rat brain without further immunosuppression. Although control transfected HEK-293T cells expressed functional rFasL, immature and differentiated mouse ES cells did not express the recombinant rFasL surface protein. Furthermore, there was no evidence for functional endogenous Fas and FasL expression on either ES cells or on neural cells after in vitro differentiation. Moreover, implanted rFasL-engineered ES cells did not survive in the rat brains in the absence of the immunosuppressive agent cyclosporine A. Our results indicate that immature and differentiated mouse ES cells do not express a functional Fas/FasL system. Disclosure of potential conflicts of interest is found at the end of this article.

The NAD+ Precursor Nicotinamide Riboside Rescues Mitochondrial Defects and Neuronal Loss in iPSC and Fly Models of Parkinson's Disease.

While mitochondrial dysfunction is emerging as key in Parkinson's disease (PD), a central question remains whether mitochondria are actual disease drivers and whether boosting mitochondrial biogenesis and function ameliorates pathology. We address these questions using patient-derived induced pluripotent stem cells and Drosophila models of GBA-related PD (GBA-PD), the most common PD genetic risk. Patient neurons display stress responses, mitochondrial demise, and changes in NAD+ metabolism. NAD+ precursors have been proposed to ameliorate age-related metabolic decline and disease. We report that increasing NAD+ via the NAD+ precursor nicotinamide riboside (NR) significantly ameliorates mitochondrial function in patient neurons. Human neurons require nicotinamide phosphoribosyltransferase (NAMPT) to maintain the NAD+ pool and utilize NRK1 to synthesize NAD+ from NAD+ precursors. Remarkably, NR prevents the age-related dopaminergic neuronal loss and motor decline in fly models of GBA-PD. Our findings suggest NR as a viable clinical avenue for neuroprotection in PD and other neurodegenerative diseases.

Surface marker profiling of SH-SY5Y cells enables small molecule screens identifying BMP4 as a modulator of neuroblastoma differentiation.

Neuroblastoma is the most common extra-cranial solid tumor in children. Its broad spectrum of clinical outcomes reflects the underlying inherent cellular heterogeneity. As current treatments often do not lead to tumor eradication, there is a need to better define therapy-resistant neuroblastoma and to identify new modulatory molecules. To this end, we performed the first comprehensive flow cytometric characterization of surface molecule expression in neuroblastoma cell lines. Exploiting an established clustering algorithm (SPADE) for unbiased visualization of cellular subsets, we conducted a multiwell screen for small molecule modulators of neuroblastoma phenotype. In addition to SH-SY5Y cells, the SH-EP, BE(2)-M17 and Kelly lines were included in follow-up analysis as in vitro models of neuroblastoma. A combinatorial detection of glycoprotein epitopes (CD15, CD24, CD44, CD57, TrkA) and the chemokine receptor CXCR4 (CD184) enabled the quantitative identification of SPADE-defined clusters differentially responding to small molecules. Exposure to bone morphogenetic protein (BMP)-4 was found to enhance a TrkAhigh/CD15-/CD184- neuroblastoma cellular subset, accompanied by a reduction in doublecortin-positive neuroblasts and of NMYC protein expression in SH-SY5Y cells. Beyond yielding novel marker candidates for studying neuroblastoma pathology, our approach may provide tools for improved pharmacological screens towards developing novel avenues of neuroblastoma diagnosis and treatment.

The Hippo pathway member YAP enhances human neural crest cell fate and migration.

The Hippo/YAP pathway serves as a major integrator of cell surface-mediated signals and regulates key processes during development and tumorigenesis. The neural crest is an embryonic tissue known to respond to multiple environmental cues in order to acquire appropriate cell fate and migration properties. Using multiple in vitro models of human neural development (pluripotent stem cell-derived neural stem cells; LUHMES, NTERA2 and SH-SY5Y cell lines), we investigated the role of Hippo/YAP signaling in neural differentiation and neural crest development. We report that the activity of YAP promotes an early neural crest phenotype and migration, and provide the first evidence for an interaction between Hippo/YAP and retinoic acid signaling in this system.

A brief perspective on neural cell therapy.

For a range of nervous system disorders current treatment options remain limited. Focusing on Parkinson's disease as a neurodegenerative entity that affects an increasing quantity of people in our aging societies, we briefly discuss remaining challenges and opportunities that neural stem cell therapy might be able to offer. Providing a snapshot of neural transplantation paradigms, we contemplate possible imminent translational scenarios and discuss critical requirements to be considered before clinical implementation.