Alzheimer's disease (AD) is associated with neuronal dysfunction and alterations ignoring the involvement of neuroglia in its apparition, evolution and treatment. Among them, astrocytes, provide CNS homeostasis as well as an active defence to the CNS through an astrogliotic response affecting their morphology, biochemical and physiological properties. Our findings in the triple transgenic mouse model (3xTg-AD) allow us to consider AD as a potential gliodegenerative process, determining its progression and outcome. We have probed this pathological role, by showing: (i) a generalized astroglial atrophy (ASPHY) with a concomitant astrogliosis just restricted to Aβ plaques (ii) alterations in glutamate glial metabolism (decrease in GS positive cells, level and expression). These alterations appear even earlier that the AD associated plaques and tangles. We performed a deep tri-dimensional morphometric analysis of different astroglial populations in sporadic and familiar Alzheimer's disease (SAD and FAD, respectively). We analyzed single GFAP and GS positive cells as well as co-localizing populations within the entorhinal cortex; comparing them with fronto-temporal dementia (FTD) and control subjects. Our results show that in both varieties exist ASPHY, with differential characteristics. SAD as happens in the 3xTg-AD shows a clear ASPHY of both GFAP and GS astrocytes (in somata and processes; 35% to 50%). FAD, however, despite showing an equivalent GFAP and GS ASPHY, this is just restricted to processes (26% to 45%) with no effect on their somata in GFAP astrocytes; but showing an even more marked atrophy in GS astrocytes. These changes are equally reflected in co-localizing populations. When compared to FTD, one can assume that astrocytic atrophy is a global dementia associated change whilst glutamate metabolic changes seem to be specific of AD. Thus, we could state that AD is not only a neuropathological process but also an early and chronic gliopathology; which in prime affected areas appear earlier than neuronal alterations. These combined glial and neural alterations are key elements in the disruption of neural networks connectivity, which associated with neurotransmitters imbalance; underlie AD mnesic deficits. Hence, new therapeutic approaches targeting simultaneously glial and neural impairments might be of major relevance for AD treatment.

High-grade serous epithelial ovarian cancer (HGSOC) is the fifth leading cause of cancer death in women and the first among gynecological malignancies. Despite an initial response to standard chemotherapy, most HGSOC patients relapse. To improve treatment options, we must continue investigating tumor biology. Tumor characteristics (e.g., risk factors and epidemiology) are valuable clues to accomplish this task. The two most frequent risk factors for HGSOC are the lifetime number of ovulations, which is associated with increased oxidative stress in the pelvic area caused by ovulation fluid, and a positive family history due to genetic factors. In the attempt to identify novel genetic factors (i.e., genes) associated with HGSOC, we observed that several genes in linkage with HGSOC are expressed in the ciliated cells of the fallopian tube. This finding made us hypothesize that ciliated cells, despite not being the cell of origin for HGSOC, may take part in HGSOC tumor initiation. Specifically, malfunction of the ciliary beat impairs the laminar fluid flow above the fallopian tube epithelia, thus likely reducing the clearance of oxidative stress caused by follicular fluid. Herein, we review the up-to-date findings dealing with HGSOC predisposition with the hypothesis that fallopian ciliated cells take part in HGSOC onset. Finally, we review the up-to-date literature concerning genes that are located in genomic loci associated with epithelial ovarian cancer (EOC) predisposition that are expressed by the fallopian ciliated cells.

Neuronal degeneration associated with Alzheimer's disease (AD), is linked to impaired calcium homeostasis and to changes in calcium-binding proteins (CBPs). The AD-related modification of neuronal CBPs remains controversial. Here we analysed the presence and expression of calretinin (CR) and parvalbumin (PV) in the hippocampal CA1 neurones of 18 months old 3xTg-AD mice compared to non-Tg animals. We found a layer specific decrease in number of interneurones expressing CR and PV (by 33.7% and 52%, respectively). Expression of PV decreased (by 13.8%) in PV-positive neurones, whereas expression of CR did not change in CR positive cells. The loss of specific subpopulations of Ca2+-binding proteins expressing interneurones (CR and PV) together with the decrease of PV in the surviving cells may be linked to their vulnerability to AD pathology. Specific loss of inhibitory interneurones with age could contribute to overall increase in the network excitability associated with AD.

The Calcium-Sensing Receptor (CaSR) is a G-protein coupled, 7-transmembrane domain receptor ubiquitously expressed throughout the body, brain including. The role of CaSR in the CNS is not well understood; its expression is increasing during development, which has been implicated in memory formation and consolidation, and CaSR localization in nerve terminals has been related to synaptic plasticity and neurotransmission. There is an emerging evidence of CaSR involvement in neurodegenerative disorders and Alzheimer's disease (AD) in particular, where the over-production of β-amyloid peptides was reported to activate CaSR. In the present study, we performed CaSR immunohistochemical and densitometry analysis in the triple transgenic mouse model of AD (3xTg-AD). We found an increase in the expression of CaSR in hippocampal CA1 area and in dentate gyrus in the 3xTg-AD mice when compared to non-transgenic control animals. This increase was significant at 9 months of age and further increased at 12 and 18 months of age. This increase paralleled the accumulation of β-amyloid plaques with age. Increased expression of CaSR favors β-amyloidogenic pathway following direct interactions between β-amyloid and CaSR and hence may contribute to the pathological evolution of the AD. In the framework of this paradigm CaSR may represent a novel therapeutic target.

The two main drivers of Alzheimer's disease (AD), amyloid-β (Aβ) and hyperphosphorylated Tau (p-Tau) oligomers, cooperatively accelerate AD progression, but a hot debate is still ongoing about which of the two appears first. Here we present preliminary evidence showing that Tau and p-Tau are expressed by untransformed cortical adult human astrocytes in culture and that exposure of such cells to an Aβ42 proxy, Aβ25-35, which binds the calcium-sensing receptor (CaSR) and activates its signaling, significantly increases intracellular p-Tau levels, an effect CaSR antagonist (calcilytic) NPS 2143 wholly hinders. The astrocytes also release both Tau and p-Tau by means of exosomes into the extracellular medium, an activity that could mediate p-Tau diffusion within the brain. Preliminary data also indicate that exosomal levels of p-Tau increase after Aβ25-35 exposure, but remain unchanged in cells pre-treated for 30-min with NPS 2143 before adding Aβ25-35. Thus, our previous and present findings raise the unifying prospect that Aβ•CaSR signaling plays a crucial role in AD development and progression by simultaneously activating (i) the amyloidogenic processing of amyloid precursor holoprotein, whose upshot is a surplus production and secretion of Aβ42 oligomers, and (ii) the GSK-3β-mediated increased production of p-Tau oligomers which are next released extracellularly inside exosomes. Therefore, as calcilytics suppress both effects on Aβ42 and p-Tau metabolic handling, these highly selective antagonists of pathological Aβ•CaSR signaling would effectively halt AD's progressive spread preserving patients' cognition and life quality.

Glial cells and their association with neurones are fundamental for brain function. The emergence of complex neurone-glial networks assures rapid information transfer, creating a sophisticated circuitry where both types of neural cells work in concert, serving different activities. All glial cells, represented by astrocytes, oligodendrocytes, microglia and NG2-glia, are essential for brain homeostasis and defence. Thus, glia are key not only for normal central nervous system (CNS) function, but also to its dysfunction, being directly associated with all forms of neuropathological processes. Therefore, the progression and outcome of neurological and neurodegenerative diseases depend on glial reactions. In this review, we provide a concise account of recent data obtained from both human material and animal models demonstrating the pathological involvement of glia in neurodegenerative processes, including Alzheimer's disease (AD), as well as physiological ageing.

The "amyloid cascade hypothesis" posits that an extracellular build-up of amyloid-β oligomers (Aβ-os) and polymers (fibrils) subsequently inducing toxic hyperphosphorylated (p)-Tau oligomers (p-Tau-os) and neurofibrillary tangles starts the sporadic late-onset Alzheimer's disease (LOAD) in the aged lateral entorhinal cortex. Conversely, mutated genes cause a diffuse cerebral Aβs/Aβ-os overproduction promoting early-onset familiar AD (EOFAD). Surplus exogenous Aβ-os exert toxic actions at several levels. They reach the nuclei of human astrocyte-neurons teams (ANTs) to enhance the transcription of Aβ precursor protein (APP) and β-secretase/BACE1 genes. The overexpressed APP and BACE1 proteins act in concert with γ-secretase to overproduce endogenous Aβs/Aβ-os, of which a few enter the nuclei to upkeep Aβs overproduction, while the rest gather in the cytoplasm, damage mitochondria, and are oversecreted. Simultaneously, extracellular Aβ-os bind the ANTs' calcium-sensing receptors (CaSRs) activating signalings that hinder the proteolysis and hence favor the surplus hoarding/secretion of Aβs/Aβ-os. Overreleased Aβ-os spread, reach growing numbers of adjacent ANTs to recruit them to overproduce/oversecrete further Aβ-os amounts via the just mentioned mechanisms. Alongside, Aβ•CaSR signalings elicit a noxious overproduction/overrelease of nitric oxide (NO) and vascular endothelial growth factor (VEGF)-A from ANTs' astrocytes. While astrocytes survive the toxic onslaught, neurons die. Thus, AD progression is driven by ceaselessly self-sustaining neurotoxic cycles, which engender first Aβ-os and later p-Tau-os that cooperatively destroy increasingly wider cognition-related cortical areas. Notably, a highly selective allosteric CaSR antagonist (calcilytic), like NPS 2143, does preserve human cortical postnatal HCN-1A neurons viability notwithstanding the presence of exogenous Aβ-os by suppressing the otherwise elicited oversecretion and spread of newly synthesized Aβ-os. Therefore, if given at minimal cognitive impairment or earlier stages, calcilytics could halt AD progression and preserve the patients' cortical neurons, cognitive abilities, and eventually life.

Evidence has begun emerging for the "contagious" and destructive Aβ42 (amyloid-beta42) oligomers and phosphorylated Tau oligomers as drivers of sporadic Alzheimer's disease (AD), which advances along a pathway starting from the brainstem or entorhinal cortex and leading to cognition-related upper cerebral cortex regions. Seemingly, Aβ42 oligomers trigger the events generating the neurotoxic Tau oligomers, which may even by themselves spread the characteristic AD neuropathology. It has been assumed that only neurons make and spread these toxic drivers, whereas their associated astrocytes are just janitorial bystanders/scavengers. But this view is likely to radically change since normal human astrocytes freshly isolated from adult cerebral cortex can be induced by exogenous Aβ25-35, an Aβ42 proxy, to make and secrete increased amounts of endogenous Aβ42. Thus, it would seem that the steady slow progression of AD neuropathology along specific cognition-relevant brain networks is driven by both Aβ42 and phosphorylated Tau oligomers that are variously released from increasing numbers of "contagion-stricken" members of tightly coupled neuron-astrocyte teams. Hence, we surmise that stopping the oversecretion and spread of the two kinds of "contagious" oligomers by such team members, perhaps via a specific CaSR (Ca(2+)-sensing receptor) antagonist like NPS 2143, might effectively treat AD.

It is generally assumed that the neuropathology of sporadic (late-onset or nonfamilial) Alzheimer’s disease (AD) is driven by the overproduction and spreading of first Amyloid-βx-42 (Aβ42) and later hyperphosphorylated (hp)-Tau oligomeric “infectious seeds”. Hitherto, only neurons were held to make and spread both oligomer types; astrocytes would just remove debris. However, we have recently shown that exogenous fibrillar or soluble Aβ peptides specifically bind and activate the Ca2+-sensing receptors (CaSRs) of untransformed human cortical adult astrocytes and postnatal neurons cultured in vitro driving them to produce, accrue, and secrete surplus endogenous Aβ42. While the Aβ-exposed neurons start dying, astrocytes survive and keep oversecreting Aβ42, nitric oxide (NO), and vascular endothelial growth factor (VEGF)-A. Thus astrocytes help neurons’ demise. Moreover, we have found that a highly selective allosteric CaSR agonist (“calcimimetic”), NPS R-568, mimics the just mentioned neurotoxic actions triggered by Aβ●CaSR signaling. Contrariwise, and most important, NPS 2143, a highly selective allosteric CaSR antagonist (“calcilytic”), fully suppresses all the Aβ●CaSR signaling-driven noxious actions. Altogether our findings suggest that the progression of AD neuropathology is promoted by unceasingly repeating cycles of accruing exogenous Aβ42 oligomers interacting with the CaSRs of swelling numbers of astrocyte-neuron teams thereby recruiting them to overrelease additional Aβ42 oligomers, VEGF-A, and NO. Calcilytics would beneficially break such Aβ/CaSR-driven vicious cycles and hence halt or at least slow the otherwise unstoppable spreading of AD neuropathology

In Saccharomyces cerevisiae and higher eukaryotes, the loading of the replicative helicase MCM2-7 onto DNA requires the combined activities of ORC, Cdc6, and Cdt1. These proteins load MCM2-7 in an unknown way into a double hexamer around DNA. Here we show that MCM2-7 recruitment by ORC/Cdc6 is blocked by an autoinhibitory domain in the C terminus of Mcm6. Interestingly, Cdt1 can overcome this inhibitory activity, and consequently the Cdt1-MCM2-7 complex activates ORC/Cdc6 ATP-hydrolysis to promote helicase loading. While Cdc6 ATPase activity is known to facilitate Cdt1 release and MCM2-7 loading, we discovered that Orc1 ATP-hydrolysis is equally important in this process. Moreover, we found that Orc1/Cdc6 ATP-hydrolysis promotes the formation of the ORC/Cdc6/MCM2-7 (OCM) complex, which functions in MCM2-7 double-hexamer assembly. Importantly, CDK-dependent phosphorylation of ORC inhibits OCM establishment to ensure once per cell cycle replication. In summary, this work reveals multiple critical mechanisms that redefine our understanding of DNA licensing.

Previously we showed that adding fibrillar (f)Aβ25–35, a proxy retaining the main physical and biological features of Aβ42, stimulated untransformed astrocytes isolated from fragments of the adult human temporal lobe cerebral cortex to synthesize and accumulate large amounts of endogenous Aβ42 and its oligomers, while releasing excess amounts of nitric oxide (NO) and of vascular endothelial growth factor (VEGF-A) [1,2]. Here, we investigated the effects of fAβ25-35 and soluble (s)Aβ25-35 on Aβ42 and Aβ40 accumulation/secretion by human cortical astrocytes and HCN- 1A neurons. And since the calcium-sensing receptor (CaSR) binds Aβs, we studied whether calcium-CaSR signaling plays any role in such Aβ25-35-elicited effects and their modulation by NPS 2143, a CaSR allosteric antagonist (calcilytic). The fAβ25- 35-exposed astrocytes and neurons produced, accumulated, and secreted increased amounts of Aβ42, while Aβ40 also accrued but its secretion was unchanged. Accordingly, secreted Aβ42/Aβ40 ratio values rose for astrocytes and neurons but NPS 2143 addition specifically suppressed the fAβ25-35-elicited surges of endogenous Aβ42 secretion by both cell types. Therefore, NPS 2143 addition always kept Aβ42/Aβ40 values to baseline or lower levels. Compared to fAβ25-35, sAβ25-35 also stimulated Aβ42 secretion by astrocytes and neurons and NPS 2143 specifically and wholly suppressed this effect. Therefore, since NPS 2143 prevents any Aβ/CaSR-induced surplus secretion of endogenous Aβ42 and hence further vicious cycles of Aβ self-induction/secretion/ spreading, the CaSR antagonists like NPS 2143 might be novel therapeutic drugs for Alzheimer’s disease.

La enfermedad de Alzheimer (EA) es una enfermedad neurodegenerativa caracterizada por la perdida de memoria y disfunciones cognitivas, entre las cuales se incluyen problemas del lenguaje, desorientacion, perdida de la capacidad de organizacion y planificacion y otros sintomas neuropsiquiatricos, hasta la llegada a un estadio final, en el cual el paciente precisa de una asistencia total. Las principales caracteristica patologicas son la atrofia cortical, la perdida de neuronas y sinapsis, la acumulacion de la proteina B-amiloide, la deposicion de placas seniles y la formacion de ovillos neurofibrilares (MNFs) constituidos por la proteina tau hiperfosforilada.