13 research outputs found

    Oligomeric and Fibrillar Species of Aβ42 Diversely Affect Human Neural Stem Cells.

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    Amyloid-β 42 peptide (Aβ1-42 (Aβ42)) is well-known for its involvement in the development of Alzheimer's disease (AD). Aβ42 accumulates and aggregates in fibers that precipitate in the form of plaques in the brain causing toxicity; however, like other forms of Aβ peptide, the role of these peptides remains unclear. Here we analyze and compare the effects of oligomeric and fibrillary Aβ42 peptide on the biology (cell death, proliferative rate, and cell fate specification) of differentiating human neural stem cells (hNS1 cell line). By using the hNS1 cells we found that, at high concentrations, oligomeric and fibrillary Aβ42 peptides provoke apoptotic cellular death and damage of DNA in these cells, but Aβ42 fibrils have the strongest effect. The data also show that both oligomeric and fibrillar Aβ42 peptides decrease cellular proliferation but Aβ42 oligomers have the greatest effect. Finally, both, oligomers and fibrils favor gliogenesis and neurogenesis in hNS1 cells, although, in this case, the effect is more prominent in oligomers. All together the findings of this study may contribute to a better understanding of the molecular mechanisms involved in the pathology of AD and to the development of human neural stem cell-based therapies for AD treatment.This work was supported by grants from the Spanish Ministry of Science and Innovation (RTI2018-101663-B-100), MICINN-ISCIII (PI-10/00291 and MPY1412/09), MINECO (SAF2015-71140-R), and Comunidad de Madrid (NEUROSTEMCM consortium; S2010/BMD-2336).S

    Advances in Alzheimer’s Disease Research: Human Cerebral Organoids

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    Alzheimer’s disease (AD) is the main neurodegenerative disorder in old age, causing memory impairment and dependency. The histopathology of AD is characterized by the presence of amyloid plaques and neurofibrillary tangles formed by Aβ peptide and hyperphosphorylated Tau, respectively. There is still no cure or effective treatment for AD. This could be due, in part, to the lack of suitable research models since animal models do not recapitulate the full physiological complexity of the human brain. With the development of induced pluripotent stem cells (iPSCs), these limitations could be overcome. Even so, the bi-dimensional (2D) culture models still do not allow to recapitulate all types of brain cells and do not show a three-dimensional (3D) arrangement. Since obtaining 3D cultures called organoids, a new opportunity arises to overcome the limitations of previous models. Human Cerebral Organoids (hCOs) represent a pioneering model, in which part of the complexity of the human brain is present. For this reason, they are fast becoming a very remarkable model for the study of the evolution of the molecular and cellular pathology of AD. This review provides a brief overview of AD research, focusing on the most recent advances achieved through the development of stem cell and cerebral organoid technologyThe authors would like to thank to financing entities: i. State R+D+i Program Oriented to the Challenges of Society. Ministry of Science and Innovation (PID2021-126715OB-I00). ii. Strategic Action in Intramural Health (PI22/00055). iii. Ministry of Science and Innovation and Universities, within the program “R&D Projects «Retos Investigación» (RTI2018-101663-B-100).S

    SINGLE-CELL sequencing workflow to study cellular composition and cell type specific expression profiles of human Cerebral Organoids

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    IBRO 11th World Congress of Neuroscience. Granada (Spain). 9-13 September 2023.Human cerebral organoid culture is a technology with immense potential in the areas of developmental neurobiology and neurodegeneration for example to study cell types, mechanisms involved, to discover of new biomarkers, to propose specific therapeutic strategies or to study the effects of compound-induced toxicity. Single-cell RNA sequencing (scRNA-seq) is a promising technology that will help to define the identity of the cerebral organoids and to understand cellular composition and cell type specific expression profiles. Standardization of workflows to do the scRNA-seq analysis is an important means to improve the use of this technology. We present the workflow and results of the scRNA-seq performed for cerebral organoids generated from the AND-2 cell line of human embryonic stem cells (hESCs). Dissociated cerebral organoid samples were loaded on the 10X Chromium and single cell libraries were prepared according to 10X Genomics standard procedures and sequenced on the Novaseq sequencer (Illumina).The data were checked and aligned to the GRCh38 human reference genome with CellRanger v6.0.2 and analyzed with Seurat v4.0. After quality filtering and data normalization with the SCTransform function, we performed Principal component analysis (PCA) using the highly variable genes, built a Shared Nearest Neighbor (SNN) graph using the Louvain method. To visualize data, Uniform Manifold Approximation and Projection (UMAP) dimensional reduction was performed. The identities of the cell clusters were assigned using the expression of genes specific of each cell type. We annotate in the AND2 cerebral organoids clusters for intermediate progenitor cells, astrocytes, oligodendrocyte precursor cells, excitatory neurons, inhibitory neurons, and mesodermal cells. We find also some cells in these organoids with expression of endothelial and microglial gene markers. Enrichment analysis of the highly variable differentially expressed genes (DEGs) was utilized to characterize the assigned cell types with Gene Ontology (GO), PanglaoDB and Cellmarker databases.S

    Efficient generation of human cerebral organoids directly from adherent cultures of pluripotent stem cells

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    Human cerebral organoids (hCOs) offer the possibility of deepening the knowledge of human brain development, as well as the pathologies that affect it. The method developed here describes the efficient generation of hCOs by going directly from two-dimensional (2D) pluripotent stem cell (PSC) cultures to three-dimensional (3D) neuroepithelial tissue, avoiding dissociation and aggregation steps. This has been achieved by subjecting 2D cultures, from the beginning of the neural induction step, to dual-SMAD inhibition in combination with CHIR99021. This is a simple and reproducible protocol in which the hCOs generated develop properly presenting proliferative ventricular zones (VZs) formed by neural precursor and radial glia (RG) that differentiate to give rise to mature neurons and glial cells. The hCOs present additional cell types such as oligodendrocyte precursors, astrocytes, microglia-like cells, and endothelial-like cells. This new approach could help to overcome some of the existing limitations in the field of organoid biotechnology, facilitating its execution in any laboratory setting.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Grant PID2021-126715OB-I00 funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe,” by the Grant of Instituto de Salud Carlos III (ISCIII) PI22CIII/00055, grant RTI2018-101663-B-100 funded by MCIN/AEI/ and the UFIECPY 398/19, PEJ2018-004965 grant to RGS funded by AEI.S

    Impact of environmental neurotoxic: current methods and usefulness of human stem cells.

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    The development of central nervous system is a highly coordinated and complex process. Any alteration of this process can lead to disturbances in the structure and function of the brain, which can cause deficits in neurological development, resulting in neurodevelopmental disorders, including, for example, autism or attention-deficit hyperactivity disorder. Exposure to certain chemicals during the fetal period and childhood is known to cause developmental neurotoxicity and has serious consequences that persist into adult life. For regulatory purposes, determination of the potential for developmental neurotoxicity is performed according the OECD Guideline 426, in which the test substance is administered to animals during gestation and lactation. However, these animal models are expensive, long-time consuming and may not reflect the physiology in humans; that makes it an unsustainable model to test the large amount of existing chemical products, hence alternative models to the use of animals are needed. One of the most promising methods is based on the use of stem cell technology. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into more specialized cell types. Because of these properties, these cells have gained increased attention as possible therapeutic agents or as disease models. Here, we provide an overview of the current models both animal and cellular, available to study developmental neurotoxicity and review in more detail the usefulness of human stem cells, their properties and how they are becoming an alternative to evaluate and study the mechanisms of action of different environmental toxicants.This work was supported by grants from the MCINN ( RTI2018-101663-B-100 ), MICINNISCIII ( PI-10/00291 and MPY1412/09 ), MINECO (SAF 2015-71140-R) and Comunidad de Madrid (NEUROSTEMCM consortium; S2010/BMD-2336 )S

    Role of Amyloid Precursor Protein (APP) and Its Derivatives in the Biology and Cell Fate Specification of Neural Stem Cells

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    Amyloid precursor protein (APP) is a member of the APP family of proteins, and different enzymatic processing leads to the production of several derivatives that are shown to have distinct biological functions. APP is involved in the pathology of Alzheimer's disease (AD), the most common neurodegenerative disorder causing dementia. Furthermore, it is believed that individuals with Down syndrome (DS) have increased APP expression, due to an extra copy of chromosome 21 (Hsa21), that contains the gene for APP. Nevertheless, the physiological function of APP remains unclear. It is known that APP plays an important role in neural growth and maturation during brain development, possibly by influencing proliferation, cell fate specification and neurogenesis of neural stem cells (NSCs). Proteolytic cleavage of APP occurs mainly via two mutually exclusive pathways, the non-amyloidogenic pathway or the amyloidogenic pathway. Other alternative pathways (η-secretase, δ-secretase and meprin pathways) have also been described for the physiological processing of APP. The different metabolites generated from these pathways, including soluble APPα (sAPPα), soluble APPβ (sAPPβ), β-amyloid (Aβ) peptides and the APP intracellular domain (AICD), have different functions determined by their structural differences, equilibrium and concentration with respect to other fragments derived from APP. This review discusses recent observations regarding possible functions of APP and its proteolytic derivatives in the biology and phenotypic specification of NSCs. This can be important for a better understanding of the pathogenesis and the development of future therapeutic applications for AD and/or DS, diseases in which alterations in neurogenesis have been described.This work has been supported by grants MICINN-ISCIII (PI10/00291 and MPY1412/09), MINECO (SAF2015-71140-R) and Comunidad de Madrid (NEUROSTEMCM consortium; S2010/BMD-2336). And grants MPY-1038/14 and MPY-1146/16 from ISCIII to Alberto Zambrano.S

    Aβ42 Peptide Promotes Proliferation and Gliogenesis in Human Neural Stem Cells

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    Amyloid-β 42 [Aβ1-42 (Aβ42)] is one of the main Aβ peptide isoforms found in amyloid plaques of brains with Alzheimer's disease (AD). Although Aβ42 is associated with neurotoxicity, it might mediate several normal physiological processes during embryonic brain development and in the adult brain. However, due to the controversy that exists in the field, relatively little is known about its physiological function. In the present work, we have analyzed the effects of different concentrations of monomeric Aβ42 on cell death, proliferation, and cell fate specification of human neural stem cells (hNSCs), specifically the hNS1 cell line, undergoing differentiation. Our results demonstrate that at higher concentrations (1 μM), Aβ42 increases apoptotic cell death and DNA damage, indicating that prolonged exposure of hNS1 cells to higher concentrations of Aβ42 is neurotoxic. However, at lower concentrations, Aβ42 significantly promotes cell proliferation and glial cell specification of hNS1 cells by increasing the pool of proliferating glial precursors, without affecting neuronal differentiation, in a concentration-dependent manner. At the molecular level, these effects could be mediated, at least in part, by GSK3β, whose expression is increased by treatment with Aβ42 and whose inhibition prevents the glial specification induced by Aβ42. Since the cellular and molecular effects are known to appear decades before the first clinical symptoms, these types of studies are important in discovering the underlying pathophysiological processes involved in the development of AD. This knowledge could then be used in diagnosing the disease at early stages and be applied to the development of new treatment options.This work was supported by grants from the MICINN-ISCIII (PI10/00291 and MPY1412/09), MINECO (SAF2015-71140-R) and Comunidad de Madrid (NEUROSTEMCM consortium; S2010/BMD-2336).S

    Background levels and brain organoid impact of RF field exposure in a healthcare environment

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    Introduction: This study is an introduction to the empirical and impact evaluation of radiofrequency electromagnetic field (RF-EMF) radiation exposure in a healthcare environment, focusing on an indoor microenvironment. It explores the expression of various genes associated with cellular responses, cell proliferation, senescence, and apoptotic cell death. The assessment analyzes current personal mobile communications (2G-5G FR1), providing a clear understanding of RF-EMF exposure and compliance with regulatory limits. Methods: The signals from different wireless communication systems at Hospital Universitario de Canarias (HUC) in Tenerife, Canary Islands, Spain, were examined in 11 locations. Four measurement campaigns were performed with frequencyselective exposimeters (PEMs) and an EME Spy 200 MVG, and experimental electric field values were compared as a long-term exposition. The frequency with the highest contribution (2.174 V/m) observed (1840 MHz) in UMTS was selected for biological effects evaluation. Results: The study focuses on four locations with the highest exposure to communication systems (downlinks), analyzing the results to verify compliance with regulations that ensure the safety of patients, the general public, and healthcare workers. LTE B20 (DL), GSM+UMTS 900 (DL), GSM 1800 (DL), UMTS 2100 (DL), and LTE B7 (DL) exhibited relatively higher E/m values throughout the campaigns, and these values consistently remained below the ICNIRP reference levels, signifying a consistently low level of exposure. In addition, this work presents the biological effects on neural stem cells (NSCs) using 3D brain organoids (BOs) exposed to RF signals in a validated and commercial experimental setting: the Gigahertz Transverse Electromagnetic cell (GTEM). The GTEM allows for the creation of homogeneous field electromagnetic fields in a small, enclosed setting and guarantees exposure conditions in a wide range of frequencies. BOs are an in vitro 3D cell-culture technology that reproduces the cellular composition and structure of the developing brain. Analyzing the expression of several genes associated with cellular responses, cell proliferation, senescence, and apoptotic cell death,wefound that exposure of BOs at 1840MHzdid not affectmRNAexpression in brain genes related to apoptosis or senescence. However, a decrease in gene expression for cell proliferation and cell activity markers was observed during the differentiation stage of BOs. Discussion: The discussion emphasizes the coexistence and evolution of various heterogeneous networks and services throughout the four measurement campaigns. Across all measured results, the levels of the obtained E-field were consistently well below the exposure limits set by internationally accepted standards and guidelines. These obtained values have been established in order to consider their potential effects on cell proliferation and cell activity, especially in differentiating biological organisms. Consequently, the results obtained and the methodology presented could serve as a foundational framework for establishing the basis of RF-EMF assessment in future heterogeneous 5G developments, particularly in the millimeter wave (mmWave) frequency range, where the forecast is for massive high-node density networks.The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This work was supported at Instituto de Salud Carlos III project “(PI19CIII/00033) TMPY 508/19” “Metrics development for electromagnetic safety assessment in healthcare centers in the context of 5G” from the Sub-Directorate-General for Research Assessment and Promotion. This research was funded by the Grant PID2021-126715OB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe,” and by a grant of the Instituto de Salud Carlos III (ISCIII) PI22CIII/00055.S

    EFFECTS OF POLYSTYRENE NANOPLASTICS ON THE BIOLOGY OF HUMAN NEURAL STEM CELLS AND HUMAN CEREBRAL ORGANOIDS.

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    IBRO 11th World Congress of Neuroscience. Granada (Spain). 9-13 September 2023.Global plastic production has increased exponentially in recent decades and a significant proportion persists in the environment, where it is degraded by mechanical and physical processes giving rise to micro (< 5mm) and nanoplastics (< 1000 nm; NP) and can reach humans through ingestion, inhalation and the dermal route. There is growing concern about the effects that NPs may cause on human health, in particular there are few studies that assess the effect of NPs on the developing brain, although they have been shown to be able to cross the blood-brain barrier and the placenta. In this study, we evaluate the effects of 30 nm polysteren NPs (PSNPs) on human neural stem cells (hNSCs) and human cerebral organoids (hCOs). In these models we perform studies on cell death, cell proliferation and phenotypic differentiation. As initial results, it can be said that the NPs penetrate cells and organoids, observing an increase of apoptotic markers at higher concentrations, indicative of cell death and alterations in cell proliferation and phenotypic differentiation. Overall, our study suggests the vulnerability of human stem cells to PSNPs exposure, resulting in functional disturbance that might lead to neurodevelopmental disorders.S
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