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Amyloid-β 40 peptides [Aβ1-40 (Aβ40)] are present within amyloid plaques in the brains of patients with Alzheimer's disease (AD). Even though Aβ peptides are considered neurotoxic, they can mediate many biological processes, both in adult brains and throughout brain development. However, the physiological function of these Aβ peptides remains poorly understood, and the existing data are sometimes controversial. Here, we analyze and compare the effects of monomeric Aβ40 on the biology of differentiating human neural stem cells (human NSCs). For that purpose, we used a model of human NSCs called hNS1. Our data demonstrated that Aβ40 at high concentrations provokes apoptotic cellular death and the damage of DNA in human NSCs while also increasing the proliferation and favors neurogenesis by raising the percentage of proliferating neuronal precursors. These effects can be mediated, at least in part, by β-catenin. These results provide evidence of how Aβ modulate/regulate human NSC proliferation and differentiation, suggesting Aβ40 may be a pro-neurogenic factor. Our data could contribute to a better understanding of the molecular mechanisms involved in AD pathology and to the development of human NSC-based therapies for AD treatment, since these results 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 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) Sí

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.

Estudio del impacto del confinamiento en los mercados bursátiles europeos, a través del análisis del premio bursátil. El premio bursátil nos permite conocer el precio real de cotización de las empresas que vamos a estudiar. En este trabajo utilizaremos el índice euro stock como índice de referencia, y estudiaremos el premio bursátil de las empresas que forman los índices de: FTSE MIB, IBEX35, CAC40 Y DAX30. Completaremos el estudio, con el análisis de las dispersión entre el índice euro STOXX y el índice de cada país, este estudio nos permitirá conocer en que grado las variaciones en el índice de cada país se debe a características propias o por el contrario se debe al empuje que hace el índice de referencia. Por último, repetiremos el estudio de los premios, pero esta vez, analizaremos las empresas del IBEX35, sector por sector, para observar que sectores fueron los más castigados con el anuncio del confinamiento.

Although amyloid-β peptide is considered neurotoxic, it may mediate several physiological processes during embryonic development and in the adult brain. The pathological function of amyloid-β peptide has been extensively studied due to its implication in Alzheimer's disease, but its physiological function remains poorly understood. Amyloid-β peptide can be detected in non-aggregated (monomeric) and aggregated (oligomeric and fibrillary) forms. Each form has different cytotoxic and/or physiological properties, so amyloid-β peptide and its role in Alzheimer's disease need to be studied further. Neural stem cells and neural precursor cells are good tools for the study on neurodegenerative diseases and can provide future therapeutic applications in diseases such as Alzheimer's disease. In this review, we provide an outline of the effects of amyloid-β peptide, in monomeric and aggregated forms, on the biology of neural stem cells/neural precursor cells, and discuss the controversies. We also describe the possible molecular targets that could be implicated in these effects, especially GSK3β. A better understanding of amyloid-β peptide (both physiological and pathological), and the signaling pathways involved are essential to advance the field of Alzheimer's disease. Funding: This work was supported by grants from the MICINN-ISCIII (PI-10/00291 and MPY1412/09), MINECO (SAF2015-71140-R) and Comunidad de Madrid (NEUROSTEMCM consortium; S2010/BMD-2336) Sí

The pathological implication of amyloid precursor protein (APP) in Alzheimer's disease has been widely documented due to its involvement in the generation of amyloid-β peptide. However, the physiological functions of APP are still poorly understood. APP is considered a multimodal protein due to its role in a wide variety of processes, both in the embryo and in the adult brain. Specifically, APP seems to play a key role in the proliferation, differentiation and maturation of neural stem cells. In addition, APP can be processed through two canonical processing pathways, generating different functionally active fragments: soluble APP-α, soluble APP-β, amyloid-β peptide and the APP intracellular C-terminal domain. These fragments also appear to modulate various functions in neural stem cells, including the processes of proliferation, neurogenesis, gliogenesis or cell death. However, the molecular mechanisms involved in these effects are still unclear. In this review, we summarize the physiological functions of APP and its main proteolytic derivatives in neural stem cells, as well as the possible signaling pathways that could be implicated in these effects. The knowledge of these functions and signaling pathways involved in the onset or during the development of Alzheimer's disease is essential to advance the understanding of the pathogenesis of Alzheimer's disease, and in the search for potential therapeutic targets. Financial support: This work was supported by grants from the Ministerio de Ciencia e Innovación-Instituto de Salud Carlos III (PI-10/00291 and MPY1412/09), Ministerio de Economía y Competitividad (SAF2015-71140-R) and Comunidad de Madrid (Neurostem-Comunidad de Madrid consortium; S2010/BMD-2336). RC was supported by grants from Plan de Empleo Juvenil-Ministerio de Economía y Competitividad. Sí

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 03-07-2020, Esta tesis tiene embargado el acceso al texto completo hasta el 03-01-2022, Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by memory loss and cognitive decline that represents the most common cause of dementia in the elderly population. One of the main histopathologic features of AD is the formation and accumulation of amyloid plaques in the brain. They are formed by extracellular fibrillary aggregates of amyloid-β peptides (Aβ) generated by the enzymatic processing of amyloid precursor protein (APP). Aβ40 and Aβ42 peptides are the main isoforms found in these amyloid plaques. Although considered neurotoxic, Aβ peptides also play an important biological role in the adult brain and during embryonic brain development. However, the physiological function of these Aβ peptides remains poorly understood and results are controversial. Aβ peptides can be detected in non-aggregated (monomeric) and aggregated forms (oligomeric and fibrillary) and each form has different cytotoxic and physiological properties. In order to better understand the physiological/pathological role of these Aβ peptides, in this thesis, we studied the effects of both Aβ peptides (Aβ40 and Aβ42) at different concentrations and different aggregation states (monomeric, oligomeric and fibrillary), on cell death, cell proliferation and cell fate specification of human neural stem cells (human NSCs) by immunocytochemistry and qRT-PCR. Our results showed that higher concentrations of both Aβ peptides are cytotoxic for these cells in all cases, but the fibrillary form is the most toxic. Regarding cell proliferation, we observed a significant increase after treatment with both Aβ peptides in monomeric form; however, we observed a decrease or no change when we studied the other forms. Finally, concerning cell fate specification, our data showed that treatment with Aβ peptides, in all states tested, significantly affects differentiation of human NSCs. Together, our results suggest that Aβ peptides affect human NSCs biology and provide us with information about their physiological/pathological role. NSCs have the capability of self-renewal and differentiate into functional glial and neuronal cells, making these cells a good tool for the study of neurodegenerative diseases and for future therapeutic applications in diseases such as AD. However, although highly valuable, they are devoid of the tridimensional component necessary for normal organ development. It has recently been described that pluripotent stem cells in a suitable environment are capable of generating three-dimensional (3D) structures called "cerebral organoids”. These 3D structures have revealed important similarities and differences between their development and that of the brain in vivo, and therefore represent a promising in vitro model to understand how the brain develops, to study the physiological pathways during development and the molecular pathology associated with neurodegenerative disorders, such as AD

The amyloid -β peptide (Aβ) is the main component of the amyloid plaques in Alzheimer's disease (AD). It has been widely demonstrated that Aβ is toxic to neurons and is associated with AD pathology. However, Aβ also appears to have an important biological function both in the adult brain and throughout embryonic development of the nervous system, acting as a trophic factor at low concentrations.It is known that Neural Stem Cells (NSCs) are capable of self-renewal and differentiate into functional glial and neuronal cells. Therefore, human NSCs may be a hope for future therapeutic application in neurodegenerative diseases such as AD. The effects of Aβ peptides on NSCs are still not well understood and remain controversial.In this chapter we outline the materials and methods used for the culture and differentiation of hNS1 cells, a cell line of human NSCs. We describe the preparation of different forms (monomeric, oligomeric and fibrillary) of Aβ peptide and subsequent cell treatment, followed by the analysis of the effects on toxicity, cell proliferation and cell fate specification of hNS1 cells.

The amyloid -β peptide (Aβ) is the main component of the amyloid plaques in Alzheimer's disease (AD). It has been widely demonstrated that Aβ is toxic to neurons and is associated with AD pathology. However, Aβ also appears to have an important biological function both in the adult brain and throughout embryonic development of the nervous system, acting as a trophic factor at low concentrations.It is known that Neural Stem Cells (NSCs) are capable of self-renewal and differentiate into functional glial and neuronal cells. Therefore, human NSCs may be a hope for future therapeutic application in neurodegenerative diseases such as AD. The effects of Aβ peptides on NSCs are still not well understood and remain controversial.In this chapter we outline the materials and methods used for the culture and differentiation of hNS1 cells, a cell line of human NSCs. We describe the preparation of different forms (monomeric, oligomeric and fibrillary) of Aβ peptide and subsequent cell treatment, followed by the analysis of the effects on toxicity, cell proliferation and cell fate specification of hNS1 cells.

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.

La importancia de los canales iónicos radica, no sólo en su implicación en procesos biológicos clave, sino en el hecho de que son dianas terapéuticas reales y potenciales. Entre estos canales iónicos encontramos los canales de potasio, involucrados en numerosos procesos celulares de vital importancia. Debido a la complejidad de estas proteínas, durante los últimos años se ha prestado especial atención a la expresión de sus homólogos procariotas, en este sentido, el canal KcsA constituye un modelo sencillo para el estudio de canales de potasio eucariotas más complejos. Durante este proyecto, se ha llevado a cabo la expresión y caracterización funcional de un canal de potasio de origen procariota: KcsA. Para ello se han utilizado dos cepas de E.coli: BL21 y M15, debido a su capacidad de expresión de la proteína de interés. Con este trabajo, se pretende determin ar el rendimiento de expresión de la proteína en ambas cepas y estudiar sus características funcionales. Tras finalizar los experimentos de expresión de la proteína y purificación, se obtuvo que la cepa BL21 presentó mayor rendimiento que la cepa M15 a la hora de expresar el canal KcsA. Por otra parte, mediante medidas electrofisiológicas se obtuvieron registros de rampas y continuos a -150 y +150mV similares en KcsA-WT expresado en ambas cepas. Por todo lo expuesto se concluye que se puede expresar indistintamente KcsA-WT en ambas cepas con resultados satisfactorios, siendo la cepa BL21 la que presenta un mayor rendimiento.