Exploring the Role of Fallopian Ciliated Cells in the Pathogenesis of High-Grade Serous Ovarian Cancer.

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.

Loss of calretinin and parvalbumin positive interneurones in the hippocampal CA1 of aged Alzheimer's disease mice.

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.

Amyloid ß-Exposed Human Astrocytes Overproduce Phospho-Tau and Overrelease It within Exosomes, Effects Suppressed by Calcilytic NPS 2143-Further Implications for Alzheimer's Therapy.

The two main drivers of Alzheimer's disease (AD), amyloid-ß (Aß) 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 Aß42 proxy, Aß25-35, 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 Aß25-35 exposure, but remain unchanged in cells pre-treated for 30-min with NPS 2143 before adding Aß25-35. Thus, our previous and present findings raise the unifying prospect that Aß•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 Aß42 oligomers, and (ii) the GSK-3ß-mediated increased production of p-Tau oligomers which are next released extracellularly inside exosomes. Therefore, as calcilytics suppress both effects on Aß42 and p-Tau metabolic handling, these highly selective antagonists of pathological Aß•CaSR signaling would effectively halt AD's progressive spread preserving patients' cognition and life quality.

Increased Calcium-Sensing Receptor Immunoreactivity in the Hippocampus of a Triple Transgenic Mouse Model of Alzheimer's Disease.

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 ß-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 ß-amyloid plaques with age. Increased expression of CaSR favors ß-amyloidogenic pathway following direct interactions between ß-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.

Complex and differential glial responses in Alzheimer's disease and ageing.

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.

Preventing the spread of Alzheimer's disease neuropathology: a role for calcilytics?

The "amyloid cascade hypothesis" posits that an extracellular build-up of amyloid-ß oligomers (Aß-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 Aßs/Aß-os overproduction promoting early-onset familiar AD (EOFAD). Surplus exogenous Aß-os exert toxic actions at several levels. They reach the nuclei of human astrocyte-neurons teams (ANTs) to enhance the transcription of Aß precursor protein (APP) and ß-secretase/BACE1 genes. The overexpressed APP and BACE1 proteins act in concert with γ-secretase to overproduce endogenous Aßs/Aß-os, of which a few enter the nuclei to upkeep Aßs overproduction, while the rest gather in the cytoplasm, damage mitochondria, and are oversecreted. Simultaneously, extracellular Aß-os bind the ANTs' calcium-sensing receptors (CaSRs) activating signalings that hinder the proteolysis and hence favor the surplus hoarding/secretion of Aßs/Aß-os. Overreleased Aß-os spread, reach growing numbers of adjacent ANTs to recruit them to overproduce/oversecrete further Aß-os amounts via the just mentioned mechanisms. Alongside, Aß•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 Aß-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 Aß-os by suppressing the otherwise elicited oversecretion and spread of newly synthesized Aß-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.

Do astrocytes collaborate with neurons in spreading the "infectious" aß and Tau drivers of Alzheimer's disease?

Evidence has begun emerging for the "contagious" and destructive Aß42 (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, Aß42 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 Aß25-35, an Aß42 proxy, to make and secrete increased amounts of endogenous Aß42. Thus, it would seem that the steady slow progression of AD neuropathology along specific cognition-relevant brain networks is driven by both Aß42 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.

An ORC/Cdc6/MCM2-7 complex is formed in a multistep reaction to serve as a platform for MCM double-hexamer assembly.

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.