YAP-dependent necrosis occurs in early stages of Alzheimer's disease and regulates mouse model pathology

YAP in development and disease: Navigating the regulatory landscape from retina to brain

The distinctive role of Yes-associated protein (YAP) in the nervous system has attracted widespread attention. This comprehensive review strategically uses the retina as a vantage point, embarking on an extensive exploration of YAP's multifaceted impact from the retina to the brain in development and pathology. Initially, we explore the crucial roles of YAP in embryonic and cerebral development. Our focus then shifts to retinal development, examining in detail YAP's regulatory influence on the development of retinal pigment epithelium (RPE) and retinal progenitor cells (RPCs), and its significant effects on the hierarchical structure and functionality of the retina. We also investigate the essential contributions of YAP in maintaining retinal homeostasis, highlighting its precise regulation of retinal cell proliferation and survival. In terms of retinal-related diseases, we explore the epigenetic connections and pathophysiological regulation of YAP in diabetic retinopathy (DR), glaucoma, and proliferative vitreoretinopathy (PVR). Lastly, we broaden our exploration from the retina to the brain, emphasizing the research paradigm of "retina: a window to the brain." Special focus is given to the emerging studies on YAP in brain disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD), underlining its potential therapeutic value in neurodegenerative disorders and neuroinflammation.

Generating PET scan patterns in Alzheimer's by a mathematical model

Alzheimer disease (AD) is the most common form of dementia. The cause of the disease is unknown, and it has no cure. Symptoms include cognitive decline, memory loss, and impairment of daily functioning. The pathological hallmarks of the disease are aggregation of plaques of amyloid-β (Aβ) and neurofibrillary tangles of tau proteins (τ), which can be detected in PET scans of the brain. The disease can remain asymptomatic for decades, while the densities of Aβ and τ continue to grow. Inflammation is considered an early event that drives the disease. In this paper, we develop a mathematical model that can produce simulated patterns of (Aβ,τ) seen in PET scans of AD patients. The model is based on the assumption that early inflammations, R and [Formula: see text], drive the growth of Aβ and τ, respectively. Recently approved drugs can slow the progression of AD in patients, provided treatment begins early, before significant damage to the brain has occurred. In line with current longitudinal studies, we used the model to demonstrate how to assess the efficacy of such drugs when given years before the disease becomes symptomatic.

Dynamic molecular network analysis of iPSC-Purkinje cells differentiation delineates roles of ISG15 in SCA1 at the earliest stage

Better understanding of the earliest molecular pathologies of all neurodegenerative diseases is expected to improve human therapeutics. We investigated the earliest molecular pathology of spinocerebellar ataxia type 1 (SCA1), a rare familial neurodegenerative disease that primarily induces death and dysfunction of cerebellum Purkinje cells. Extensive prior studies have identified involvement of transcription or RNA-splicing factors in the molecular pathology of SCA1. However, the regulatory network of SCA1 pathology, especially central regulators of the earliest developmental stages and inflammatory events, remains incompletely understood. Here, we elucidated the earliest developmental pathology of SCA1 using originally developed dynamic molecular network analyses of sequentially acquired RNA-seq data during differentiation of SCA1 patient-derived induced pluripotent stem cells (iPSCs) to Purkinje cells. Dynamic molecular network analysis implicated histone genes and cytokine-relevant immune response genes at the earliest stages of development, and revealed relevance of ISG15 to the following degradation and accumulation of mutant ataxin-1 in Purkinje cells of SCA1 model mice and human patients.

Another Use for a Proven Drug: Experimental Evidence for the Potential of Artemisinin and Its Derivatives to Treat Alzheimer's Disease

Plant-derived multitarget compounds may represent a promising therapeutic strategy for multifactorial diseases, such as Alzheimer's disease (AD). Artemisinin and its derivatives were indicated to beneficially modulate various aspects of AD pathology in different AD animal models through the regulation of a wide range of different cellular processes, such as energy homeostasis, apoptosis, proliferation and inflammatory pathways. In this review, we aimed to provide an up-to-date overview of the experimental evidence documenting the neuroprotective activities of artemi-sinins to underscore the potential of these already-approved drugs for treating AD also in humans and propose their consideration for carefully designed clinical trials. In particular, the benefits to the main pathological hallmarks and events in the pathological cascade throughout AD development in different animal models of AD are summarized. Moreover, dose- and context-dependent effects of artemisinins are noted.

Necrosis Links Neurodegeneration and Neuroinflammation in Neurodegenerative Disease

The mechanisms of neuronal cell death in neurodegenerative disease remain incompletely understood, although recent studies have made significant advances. Apoptosis was previously considered to be the only mechanism of neuronal cell death in neurodegenerative diseases. However, recent findings have challenged this dogma, identifying new subtypes of necrotic neuronal cell death. The present review provides an updated summary of necrosis subtypes and discusses their potential roles in neurodegenerative cell death. Among numerous necrosis subtypes, including necroptosis, paraptosis, ferroptosis, and pyroptosis, transcriptional repression-induced atypical cell death (TRIAD) has been identified as a potential mechanism of neuronal cell death. TRIAD is induced by functional deficiency of TEAD-YAP and self-amplifies via the release of HMGB1. TRIAD is a feasible potential mechanism of neuronal cell death in Alzheimer's disease and other neurodegenerative diseases. In addition to induction of cell death, HMGB1 released during TRIAD activates brain inflammatory responses, which is a potential link between neurodegeneration and neuroinflammation.

Cell type-specific roles of APOE4 in Alzheimer disease

The ɛ4 allele of the apolipoprotein E gene (APOE), which translates to the APOE4 isoform, is the strongest genetic risk factor for late-onset Alzheimer disease (AD). Within the CNS, APOE is produced by a variety of cell types under different conditions, posing a challenge for studying its roles in AD pathogenesis. However, through powerful advances in research tools and the use of novel cell culture and animal models, researchers have recently begun to study the roles of APOE4 in AD in a cell type-specific manner and at a deeper and more mechanistic level than ever before. In particular, cutting-edge omics studies have enabled APOE4 to be studied at the single-cell level and have allowed the identification of critical APOE4 effects in AD-vulnerable cellular subtypes. Through these studies, it has become evident that APOE4 produced in various types of CNS cell - including astrocytes, neurons, microglia, oligodendrocytes and vascular cells - has diverse roles in AD pathogenesis. Here, we review these scientific advances and propose a cell type-specific APOE4 cascade model of AD. In this model, neuronal APOE4 emerges as a crucial pathological initiator and driver of AD pathogenesis, instigating glial responses and, ultimately, neurodegeneration. In addition, we provide perspectives on future directions for APOE4 research and related therapeutic developments in the context of AD.

Global Research Trends and Hotspots for Ferroptosis, Necroptosis, and Pyroptosis in Alzheimer's Disease from the Past to 2023: A Combined Bibliometric Review

Background

Alzheimer's disease (AD) is a genetically intricate neurodegenerative disorder. Studies on "Ferroptosis in AD", "Pyroptosis in AD", and "Necroptosis in AD" are becoming more prevalent and there is increasing evidence that they are closely related to AD. However, there has not yet been a thorough bibliometrics-based investigation on this subject.

Objective

This study uses a bibliometric approach to visualize and analyze the literature within the field of three distinct types of cell death in AD and explores the current research hotspots and prospective research directions.

Methods

We collected relevant articles from the Web of Science and used CiteSpace, VOS viewer, and Pajek to perform a visual analysis.

Results

A total of 123, 95, and 84 articles were published in "Ferroptosis in AD", "Pyroptosis in AD", and "Necroptosis in AD", respectively. Based on keywords analysis, we can observe that "oxidative stress" and "lipid peroxidation", "cell death" and "activation", and "Nlrp3 inflammasome" and "activation" were the three most prominent words in the field of "Ferroptosis in AD", "Pyroptosis in AD", and "Necroptosis in AD", respectively. Focusing on the breakout words in the keyword analysis, we reviewed the mechanisms of ferroptosis, pyroptosis, and necroptosis in AD. By mapping the time zones of the keywords, we speculated on the evolutionary trends of ferroptosis, pyrotosis, and necroptosis in AD.

Conclusions

Our findings can help researchers grasp the research status of three types of cell death in AD and determine new directions for future research as soon as possible.

Senescence, brain inflammation, and oligomeric tau drive cognitive decline in Alzheimer's disease: Evidence from clinical and preclinical studies

Aging, tau pathology, and chronic inflammation in the brain play crucial roles in synaptic loss, neurodegeneration, and cognitive decline in tauopathies, including Alzheimer's disease. Senescent cells accumulate in the aging brain, accelerate the aging process, and promote tauopathy progression through their abnormal inflammatory secretome known as the senescence-associated secretory phenotype (SASP). Tau oligomers (TauO)-the most neurotoxic tau species-are known to induce senescence and the SASP, which subsequently promote neuropathology, inflammation, oxidative stress, synaptic dysfunction, neuronal death, and cognitive dysfunction. TauO, brain inflammation, and senescence are associated with heterogeneity in tauopathy progression and cognitive decline. However, the underlying mechanisms driving the disease heterogeneity remain largely unknown, impeding the development of therapies for tauopathies. Based on clinical and preclinical evidence, this review highlights the critical role of TauO and senescence in neurodegeneration. We discuss key knowledge gaps and potential strategies for targeting senescence and TauO to treat tauopathies. HIGHLIGHTS: Senescence, oligomeric Tau (TauO), and brain inflammation accelerate the aging process and promote the progression of tauopathies, including Alzheimer's disease. We discuss their role in contributing to heterogeneity in tauopathy and cognitive decline. We highlight strategies to target senescence and TauO to treat tauopathies while addressing key knowledge gaps.

Detection of APP gene recombinant in human blood plasma

The pathogenesis of Alzheimer's disease (AD) is believed to involve the accumulation of amyloid-β in the brain, which is produced by the sequential cleavage of amyloid precursor protein (APP) by β-secretase and γ-secretase. Recently, analysis of genomic DNA and mRNA from postmortem brain neurons has revealed intra-exonic recombinants of APP (gencDNA), which have been implicated in the accumulation of amyloid-β. In this study, we computationally analyzed publicly available sequence data (SRA) using probe sequences we constructed to screen APP gencDNAs. APP gencDNAs were detected in SRAs constructed from both genomic DNA and RNA obtained from the postmortem brain and in the SRA constructed from plasma cell-free mRNA (cf-mRNA). The SRA constructed from plasma cf-mRNA showed a significant difference in the number of APP gencDNA reads between SAD and NCI: the p-value from the Mann-Whitney U test was 5.14 × 10-6. The transcripts were also found in circulating nucleic acids (CNA) from our plasma samples with NGS analysis. These data indicate that transcripts of APP gencDNA can be detected in blood plasma and suggest the possibility of using them as blood biomarkers for Alzheimer's disease.

Hypoxia-sensing VGLL4 promotes LDHA-driven lactate production to ameliorate neuronal dysfunction in a cellular model relevant to Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease where abnormal amyloidogenic processing of amyloid-β precursor protein (APP) occurs and has been linked to neuronal dysfunction. Hypometabolism of glucose in the brain can lead to synaptic loss and neuronal death, which in turn exacerbates energy deficiency and amyloid-β peptide (Aβ) accumulation. Lactate produced by anaerobic glycolysis serves as an energy substrate supporting neuronal function and facilitating neuronal repair. Vestigial-like family member 4 (VGLL4) has been recognized as a key regulator of the hypoxia-sensing pathway. However, the role of VGLL4 in AD remains unexplored. Here, we reported that the expression of VGLL4 protein was significantly decreased in the brain tissue of AD model mice and AD model cells. We further found that overexpression of VGLL4 reduced APP amyloidogenic processing and ameliorated neuronal synaptic damage. Notably, we identified a compromised hypoxia-sensitive capability of LDHA regulated by VGLL4 in the context of AD. Upregulation of VGLL4 increased the response of LDHA to hypoxia and enhanced the expression levels of LDHA and lactate by inhibiting the ubiquitination and degradation of LDHA. Furthermore, the inhibition of lactate production by using sodium oxamate, an inhibitor of LDHA, suppressed the neuroprotective function of VGLL4 by increasing APP amyloidogenic processing. Taken together, our findings demonstrate that VGLL4 exerts a neuroprotective effect by upregulating LDHA expression and consequently promoting lactate production. Thus, this study suggests that VGLL4 may be a novel player involved in molecular mechanisms relevant for ameliorating neurodegeneration.

Development of an accelerated cellular model for early changes in Alzheimer's disease

Alzheimer's Disease (AD) is a leading cause of dementia characterized by amyloid plaques and neurofibrillary tangles, and its pathogenesis remains unclear. Current cellular models for AD often require several months to exhibit phenotypic features due to the lack of an aging environment in vitro. Lamin A is a key component of the nuclear lamina. Progerin, a truncated protein resulting from specific lamin A mutations, causes Hutchinson-Gilford Progeria Syndrome (HGPS), a disease that prematurely ages individuals. Studies have reported that lamin A expression is induced in the brains of AD patients, and overlapping cellular phenotypes have been observed between HGPS and AD cells. In this study, we investigated the effects of exogenous progerin expression on neural progenitor cells carrying familial AD mutations (FAD). Within three to four weeks of differentiation, these cells exhibited robust AD phenotypes, including increased tau phosphorylation, amyloid plaque accumulation, and an elevated Aβ42 to Aβ40 ratio. Additionally, progerin expression significantly increased AD cellular phenotypes such as cell death and cell cycle re-entry. Our results suggest that progerin expression could be used to create an accelerated model for AD development and drug screening.

Reprogramming iPSCs to study age-related diseases: Models, therapeutics, and clinical trials

The unprecedented rise in life expectancy observed in the last decades is leading to a global increase in the ageing population, and age-associated diseases became an increasing societal, economic, and medical burden. This has boosted major efforts in the scientific and medical research communities to develop and improve therapies to delay ageing and age-associated functional decline and diseases, and to expand health span. The establishment of induced pluripotent stem cells (iPSCs) by reprogramming human somatic cells has revolutionised the modelling and understanding of human diseases. iPSCs have a major advantage relative to other human pluripotent stem cells as their obtention does not require the destruction of embryos like embryonic stem cells do, and do not have a limited proliferation or differentiation potential as adult stem cells. Besides, iPSCs can be generated from somatic cells from healthy individuals or patients, which makes iPSC technology a promising approach to model and decipher the mechanisms underlying the ageing process and age-associated diseases, study drug effects, and develop new therapeutic approaches. This review discusses the advances made in the last decade using iPSC technology to study the most common age-associated diseases, including age-related macular degeneration (AMD), neurodegenerative and cardiovascular diseases, brain stroke, cancer, diabetes, and osteoarthritis.

Shared genetic risk loci between Alzheimer's disease and related dementias, Parkinson's disease, and amyotrophic lateral sclerosis

BACKGROUND

Genome-wide association studies (GWAS) have indicated moderate genetic overlap between Alzheimer's disease (AD) and related dementias (ADRD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), neurodegenerative disorders traditionally considered etiologically distinct. However, the specific genetic variants and loci underlying this overlap remain almost entirely unknown.

METHODS

We leveraged state-of-the-art GWAS for ADRD, PD, and ALS. For each pair of disorders, we examined each of the GWAS hits for one disorder and tested whether they were also significant for the other disorder, applying Bonferroni correction for the number of variants tested. This approach rigorously controls the family-wise error rate for both disorders, analogously to genome-wide significance.

RESULTS

Eleven loci with GWAS hits for one disorder were also associated with one or both of the other disorders: one with all three disorders (the MAPT/KANSL1 locus), five with ADRD and PD (near LCORL, CLU, SETD1A/KAT8, WWOX, and GRN), three with ADRD and ALS (near GPX3, HS3ST5/HDAC2/MARCKS, and TSPOAP1), and two with PD and ALS (near GAK/TMEM175 and NEK1). Two of these loci (LCORL and NEK1) were associated with an increased risk of one disorder but decreased risk of another. Colocalization analysis supported a shared causal variant between ADRD and PD at the CLU, WWOX, and LCORL loci, between ADRD and ALS at the TSPOAP1 locus, and between PD and ALS at the NEK1 and GAK/TMEM175 loci. To address the concern that ADRD is an imperfect proxy for AD and that the ADRD and PD GWAS have overlapping participants (nearly all of which are from the UK Biobank), we confirmed that all our ADRD associations had nearly identical odds ratios in an AD GWAS that excluded the UK Biobank, and all but one remained nominally significant (p < 0.05) for AD.

CONCLUSIONS

In one of the most comprehensive investigations to date of pleiotropy between neurodegenerative disorders, we identify eleven genetic risk loci shared among ADRD, PD, and ALS. These loci support lysosomal/autophagic dysfunction (GAK/TMEM175, GRN, KANSL1), neuroinflammation/immunity (TSPOAP1), oxidative stress (GPX3, KANSL1), and the DNA damage response (NEK1) as transdiagnostic processes underlying multiple neurodegenerative disorders.

An update on the role of Hippo signaling pathway in ischemia-associated central nervous system diseases

The most frequent reason of morbidity and mortality in the world, cerebral ischemia sets off a chain of molecular and cellular pathologies that associated with some central nervous system (CNS) disorders mainly including ischemic stroke, Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy and other CNS diseases. In recent times, despite significant advancements in the treatment of the pathological processes underlying various neurological illnesses, effective therapeutic approaches that are specifically targeted to minimizing the damage of such diseases remain absent. Hippo signaling pathway, characterized by enzyme linked reactions between MSTI/2, LAST1/2, and YAP or TAZ proteins, controls cell division, survival, and differentiation, as well as being engaged in a variety of biological activities, such as the development and transformation of the nervous system. Recently, accumulating studies demonstrated that Hippo pathway takes part in the processes of ischemic stroke, AD, PD, etc., including but not limited to oxidative stress, inflammatory response, blood-brain barrier damage, mitochondrial disorders, and neural cells death. Thus, it's crucial to understand the molecular basis of the Hippo signaling pathway for determining potential new therapeutic targets against ischemia-associated CNS diseases. Here, we discuss latest advances in the deciphering of the Hippo signaling pathway and highlight the therapeutic potential of targeting the pathway in treating ischemia-associated CNS diseases.

Neuronopathic Gaucher disease models reveal defects in cell growth promoted by Hippo pathway activation

Gaucher Disease (GD), the most common lysosomal disorder, arises from mutations in the GBA1 gene and is characterized by a wide spectrum of phenotypes, ranging from mild hematological and visceral involvement to severe neurological disease. Neuronopathic patients display dramatic neuronal loss and increased neuroinflammation, whose molecular basis are still unclear. Using a combination of Drosophila dGBA1b loss-of-function models and GD patient-derived iPSCs differentiated towards neuronal precursors and mature neurons we showed that different GD- tissues and neuronal cells display an impairment of growth mechanisms with an increased cell death and reduced proliferation. These phenotypes are coupled with the downregulation of several Hippo transcriptional targets, mainly involved in cells and tissue growth, and YAP exclusion from nuclei. Interestingly, Hippo knock-down in the GBA-KO flies rescues the proliferative defect, suggesting that targeting the Hippo pathway can be a promising therapeutic approach to neuronopathic GD.

Long term exposure of saxitoxin induced cognitive deficits and YAP1 cytoplasmic retention

While most studies assessed the acute toxicity of saxitoxin (STX), fewer studies focus on the long-term degenerative effects of STX on the central nervous system. We investigated the cognitive impairment and hippocampal damages of 6 months' exposure of low-dose STX to C57BL/6NJ mice with behavioral tests, H&E staining, and Western blots, and the possible mechanism (Ppp1C, YAP1, tau-phosphorylation) underlies the pathological changes. Furthermore, we discussed the specific localization of YAP1 in N2a cells induced by STX and the effect of inactivated Ppp1C on its downstream protein YAP1 in the Hippo signal pathway. We found STX intoxicated mice showed declined cognitive performance in both NOR test and MWM test, degenerations in the CA1 area of hippocampi. STX induced up-regulation expression of Ppp1C and YAP1 in hippocampus and N2a cells. Meanwhile, STX treatment induced cell apoptosis and Tau protein hyperphosphorylation. In addition, STX treatment promoted YAP1 cytoplasmic retention that indicates the activation of Hippo pathway, while depletion of Ppp1C inactivate YAP1 during the treatment of STX. Our results highlight the role of Ppp1C and YAP1 cytoplasmic retention in chronic low-dose STX intoxication.

Artemisia annua Extract Improves the Cognitive Deficits and Reverses the Pathological Changes of Alzheimer’s Disease via Regulating YAP Signaling

Alzheimer’s disease (AD) is a chronic neurodegenerative disease characterized by the occurrence of cognitive deficits. With no effective treatments available, the search for new effective therapies has become a major focus of interest. In the present study, we describe the potential therapeutic effect of Artemisia annua (A. annua) extract on AD. Nine-month-old female 3xTg AD mice were treated with A. annua extract for three months via oral administration. Animals assigned to WT and model groups were administrated with an equal volume of water for the same period. Treated AD mice significantly improved the cognitive deficits and exhibited reduced Aβ accumulation, hyper-phosphorylation of tau, inflammatory factor release and apoptosis when compared with untreated AD mice. Moreover, A. annua extract promoted the survival and proliferation of neural progenitor cells (NPS) and increased the expression of synaptic proteins. Further assessment of the implicated mechanisms revealed that A. annua extract regulates the YAP signaling pathway in 3xTg AD mice. Further studies comprised the incubation of PC12 cells with Aβ1–42 at a concentration of 8 μM with or without different concentrations of A. annua extract for 24 h. Obtained ROS levels, mitochondrial membrane potential, caspase-3 activity, neuronal cell apoptosis and assessment of the signaling pathways involved was performed using western blot and immunofluorescence staining. The obtained results showed that A. annua extract significantly reversed the Aβ1–42-induced increase in ROS levels, caspase-3 activity and neuronal cell apoptosis in vitro. Moreover, either inhibition of the YAP signaling pathway, using a specific inhibitor or CRISPR cas9 knockout of YAP gene, reduced the neuroprotective effect of the A. annua extract. These findings suggest that A. annua extract may be a new multi-target anti-AD drug with potential use in the prevention and treatment of AD.

Genome-wide association study of brain biochemical phenotypes reveals distinct genetic architecture of Alzheimer's disease related proteins

BACKGROUND

Alzheimer's disease (AD) is neuropathologically characterized by amyloid-beta (Aβ) plaques and neurofibrillary tangles. The main protein components of these hallmarks include Aβ40, Aβ42, tau, phosphor-tau, and APOE. We hypothesize that genetic variants influence the levels and solubility of these AD-related proteins in the brain; identifying these may provide key insights into disease pathogenesis.

METHODS

Genome-wide genotypes were collected from 441 AD cases, imputed to the haplotype reference consortium (HRC) panel, and filtered for quality and frequency. Temporal cortex levels of five AD-related proteins from three fractions, buffer-soluble (TBS), detergent-soluble (Triton-X = TX), and insoluble (Formic acid = FA), were available for these same individuals. Variants were tested for association with each quantitative biochemical measure using linear regression, and GSA-SNP2 was used to identify enriched Gene Ontology (GO) terms. Implicated variants and genes were further assessed for association with other relevant variables.

RESULTS

We identified genome-wide significant associations at seven novel loci and the APOE locus. Genes and variants at these loci also associate with multiple AD-related measures, regulate gene expression, have cell-type specific enrichment, and roles in brain health and other neuropsychiatric diseases. Pathway analysis identified significant enrichment of shared and distinct biological pathways.

CONCLUSIONS

Although all biochemical measures tested reflect proteins core to AD pathology, our results strongly suggest that each have unique genetic architecture and biological pathways that influence their specific biochemical states in the brain. Our novel approach of deep brain biochemical endophenotype GWAS has implications for pathophysiology of proteostasis in AD that can guide therapeutic discovery efforts focused on these proteins.

PQBP5/NOL10 maintains and anchors the nucleolus under physiological and osmotic stress conditions

Polyglutamine binding protein 5 (PQBP5), also called nucleolar protein 10 (NOL10), binds to polyglutamine tract sequences and is expressed in the nucleolus. Using dynamic imaging of high-speed atomic force microscopy, we show that PQBP5/NOL10 is an intrinsically disordered protein. Super-resolution microscopy and correlative light and electron microscopy method show that PQBP5/NOL10 makes up the skeletal structure of the nucleolus, constituting the granule meshwork in the granular component area, which is distinct from other nucleolar substructures, such as the fibrillar center and dense fibrillar component. In contrast to other nucleolar proteins, which disperse to the nucleoplasm under osmotic stress conditions, PQBP5/NOL10 remains in the nucleolus and functions as an anchor for reassembly of other nucleolar proteins. Droplet and thermal shift assays show that the biophysical features of PQBP5/NOL10 remain stable under stress conditions, explaining the spatial role of this protein. PQBP5/NOL10 can be functionally depleted by sequestration with polyglutamine disease proteins in vitro and in vivo, leading to the pathological deformity or disappearance of the nucleolus. Taken together, these findings indicate that PQBP5/NOL10 is an essential protein needed to maintain the structure of the nucleolus.

Parabrachial-to-parasubthalamic nucleus pathway mediates fear-induced suppression of feeding in male mice

Feeding behavior is adaptively regulated by external and internal environment, such that feeding is suppressed when animals experience pain, sickness, or fear. While the lateral parabrachial nucleus (lPB) plays key roles in nociception and stress, neuronal pathways involved in feeding suppression induced by fear are not fully explored. Here, we investigate the parasubthalamic nucleus (PSTN), located in the lateral hypothalamus and critically involved in feeding behaviors, as a target of lPB projection neurons. Optogenetic activation of lPB-PSTN terminals in male mice promote avoidance behaviors, aversive learning, and suppressed feeding. Inactivation of the PSTN and lPB-PSTN pathway reduces fear-induced feeding suppression. Activation of PSTN neurons expressing pituitary adenylate cyclase-activating polypeptide (PACAP), a neuropeptide enriched in the PSTN, is sufficient for inducing avoidance behaviors and feeding suppression. Blockade of PACAP receptors impaires aversive learning induced by lPB-PSTN photomanipulation. These findings indicate that lPB-PSTN pathway plays a pivotal role in fear-induced feeding suppression.

Sequestration of cellular native factors by biomolecular assemblies: Physiological or pathological?

In addition to native-state structures, biomolecules often form condensed supramolecular assemblies or cellular membraneless organelles that are critical for cell life. These biomolecular assemblies, generally including liquid-like droplets (condensates) and amyloid-like aggregates, can sequester or recruit their interacting partners, so as to either modulate various cellular behaviors or even cause disorders. This review article summarizes recent advances in the sequestration of native factors by biomolecular assemblies and discusses their potential consequences on cellular function, homeostasis, and disease pathology.

Crosstalk between the Hippo Pathway and the Wnt Pathway in Huntington's Disease and Other Neurodegenerative Disorders

The Hippo pathway consists of a cascade of kinases that controls the phosphorylation of the co-activators YAP/TAZ. When unphosphorylated, YAP and TAZ translocate into the nucleus, where they mainly bind to the TEAD transcription factor family and activate genes related to cell proliferation and survival. In this way, the inhibition of the Hippo pathway promotes cell survival, proliferation, and stemness fate. Another pathway can modulate these processes, namely the Wnt/β-catenin pathway that is indeed involved in cellular functions such as proliferation and cell survival, as well as apoptosis, growth, and cell renewal. Wnt signaling can act in a canonical or noncanonical way, depending on whether β-catenin is involved in the process. In this review, we will focus only on the canonical Wnt pathway. It has emerged that YAP/TAZ are components of the β-catenin destruction complex and that there is a close relationship between the Hippo pathway and the canonical Wnt pathway. Furthermore, recent data have shown that both of these pathways may play a role in neurodegenerative diseases, such as Huntington's disease, Alzheimer's disease, or Amyotrophic Lateral Sclerosis. Thus, this review analyzes the Hippo pathway and the Wnt pathway, their crosstalk, and their involvement in Huntington's disease, as well as in other neurodegenerative disorders. Altogether, these data suggest possible therapeutic approaches targeting key players of these pathways.

Trilobatin rescues cognitive impairment of Alzheimer's disease by targeting HMGB1 through mediating SIRT3/SOD2 signaling pathway

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with cognitive impairment that currently is uncurable. Previous study shows that trilobatin (TLB), a naturally occurring food additive, exerts neuroprotective effect in experimental models of AD. In the present study we investigated the molecular mechanisms underlying the beneficial effect of TLB on experimental models of AD in vivo and in vitro. APP/PS1 transgenic mice were administered TLB (4, 8 mg· kg-1 ·d-1, i.g.) for 3 months; rats were subjected to ICV injection of Aβ25-35, followed by administration of TLB (2.5, 5, 10 mg· kg-1 ·d-1, i.g.) for 14 days. We showed that TLB administration significantly and dose-dependently ameliorated the cognitive deficits in the two AD animal models, assessed in open field test, novel object recognition test, Y-maze test and Morris water maze test. Furthermore, TLB administration dose-dependently inhibited microglia and astrocyte activation in the hippocampus of APP/PS1 transgenic mice accompanied by decreased expression of high-mobility group box 1 (HMGB1), TLR4 and NF-κB. In Aβ25-25-treated BV2 cells, TLB (12.5-50 μM) concentration-dependently increased the cell viability through inhibiting HMGB1/TLR4/NF-κB signaling pathway. HMGB1 overexpression abrogated the beneficial effects of TLB on BV2 cells after Aβ25-35 insults. Molecular docking and surface plasmon resonance assay revealed that TLB directly bound to HMGB1 with a KD value of 8.541×10-4 M. Furthermore, we demonstrated that TLB inhibited Aβ25-35-induced acetylation of HMGB1 through activating SIRT3/SOD2 signaling pathway, thereby restoring redox homeostasis and suppressing neuroinflammation. These results, for the first time, unravel a new property of TLB: rescuing cognitive impairment of AD via targeting HMGB1 and activating SIRT3/SOD2 signaling pathway.

Biochemical Pathways of Cellular Mechanosensing/Mechanotransduction and Their Role in Neurodegenerative Diseases Pathogenesis

In this review, we shed light on recent advances regarding the characterization of biochemical pathways of cellular mechanosensing and mechanotransduction with particular attention to their role in neurodegenerative disease pathogenesis. While the mechanistic components of these pathways are mostly uncovered today, the crosstalk between mechanical forces and soluble intracellular signaling is still not fully elucidated. Here, we recapitulate the general concepts of mechanobiology and the mechanisms that govern the mechanosensing and mechanotransduction processes, and we examine the crosstalk between mechanical stimuli and intracellular biochemical response, highlighting their effect on cellular organelles' homeostasis and dysfunction. In particular, we discuss the current knowledge about the translation of mechanosignaling into biochemical signaling, focusing on those diseases that encompass metabolic accumulation of mutant proteins and have as primary characteristics the formation of pathological intracellular aggregates, such as Alzheimer's Disease, Huntington's Disease, Amyotrophic Lateral Sclerosis and Parkinson's Disease. Overall, recent findings elucidate how mechanosensing and mechanotransduction pathways may be crucial to understand the pathogenic mechanisms underlying neurodegenerative diseases and emphasize the importance of these pathways for identifying potential therapeutic targets.

Extracellular microRNA and cognitive function in a prospective cohort of older men: The Veterans Affairs Normative Aging Study

BACKGROUND

Aging-related cognitive decline is an early symptom of Alzheimer's disease and other dementias, and on its own can have substantial consequences on an individual's ability to perform important everyday functions. Despite increasing interest in the potential roles of extracellular microRNAs (miRNAs) in central nervous system (CNS) pathologies, there has been little research on extracellular miRNAs in early stages of cognitive decline. We leverage the longitudinal Normative Aging Study (NAS) cohort to investigate associations between plasma miRNAs and cognitive function among cognitively normal men.

METHODS

This study includes data from up to 530 NAS participants (median age: 71.0 years) collected from 1996 to 2013, with a total of 1,331 person-visits (equal to 2,471 years of follow up). Global cognitive function was assessed using the Mini-Mental State Examination (MMSE). Plasma miRNAs were profiled using small RNA sequencing. Associations of expression of 381 miRNAs with current cognitive function and rate of change in cognitive function were assessed using linear regression (N = 457) and linear mixed models (N = 530), respectively.

RESULTS

In adjusted models, levels of 2 plasma miRNAs were associated with higher MMSE scores (p < 0.05). Expression of 33 plasma miRNAs was associated with rate of change in MMSE scores over time (p < 0.05). Enriched KEGG pathways for miRNAs associated with concurrent MMSE and MMSE trajectory included Hippo signaling and extracellular matrix-receptor interactions. Gene targets of miRNAs associated with MMSE trajectory were additionally associated with prion diseases and fatty acid biosynthesis.

CONCLUSIONS

Circulating miRNAs were associated with both cross-sectional cognitive function and rate of change in cognitive function among cognitively normal men. Further research is needed to elucidate the potential functions of these miRNAs in the CNS and investigate relationships with other neurological outcomes.

Application of Micro-Western Array for Identifying Different Serum Protein Expression Profile among Healthy Control, Alzheimer’s Disease Patients and Patients’ Adult Children

(1) Background: Alzheimer’s disease (AD) is the most common form of dementia. Increased levels of inflammatory proteins have been observed in brain and plasma samples of AD patients; however, it is not clear if other serum proteins correlate to the development or disease progression of AD. (2) Methods: Micro-Western Array (MWA) is a high-throughput antibody-based proteomics system which allows detection of the expression levels of 24–96 different proteins within 6–30 samples simultaneously. We applied MWA to explore potential serum protein biomarkers correlated to the development and progression of AD by examining the difference in serum protein profile of 31 healthy control (HC), 30 patients with AD and 30 patients’ adult children (ACS). (3) Results: Compared to HC, AD and ACS express similar pattern of serum proteins, including higher protein levels of ABCA1, ABCG1, SREBP1 and LXRβ but lower protein levels of ApoD, ApoE, ApoH, c_Myc, COX2 and Hippo-YAP signaling proteins. AD patients had higher serum levels of ABCG1, ApoD, ApoH, COX2, LXRα and YAP, but lower levels of ABCA1, ApoE, c_Myc, LATS1, MST1, MST2, Nanog, NFκB_p50, PPARγ and SREBP2, as compared to ACS. Pearson’s correlation analysis revealed that the protein expression level of ApoE, c_Myc, LATS1, MST2, NFκB p50, PPARγ and SREBP1 was negatively correlated to age, while that of ApoE, c_Myc, LATS1, MST1, MST2, Nanog, NFκB p50 and PPARγ was positively correlated to age. (4) Conclusions: We identified a group of serum proteins which may correlate to disease progression of AD and can be potential diagnostic serum protein biomarkers.

Neuronal cell death mechanisms in Alzheimer's disease: An insight

Regulated cell death (RCD) is an ordered and tightly orchestrated set of changes/signaling events in both gene expression and protein activity and is responsible for normal development as well as maintenance of tissue homeostasis. Aberrant activation of this pathway results in cell death by various mechanisms including apoptosis, necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death. Such pathological changes in neurons alone or in combination have been observed in the pathogenesis of various neurodegenerative diseases including Alzheimer's disease (AD). Pathological hallmarks of AD focus primarily on the accumulation of two main protein markers: amyloid β peptides and abnormally phosphorylated tau proteins. These protein aggregates result in the formation of A-β plaques and neuro-fibrillary tangles (NFTs) and induce neuroinflammation and neurodegeneration over years to decades leading to a multitude of cognitive and behavioral deficits. Autopsy findings of AD reveal massive neuronal death manifested in the form of cortical volume shrinkage, reduction in sizes of gyri to up to 50% and an increase in the sizes of sulci. Multiple forms of cell death have been recorded in neurons from different studies conducted so far. However, understanding the mechanism/s of neuronal cell death in AD patients remains a mystery as the trigger that results in aberrant activation of RCD is unknown and because of the limited availability of dying neurons. This review attempts to elucidate the process of Regulated cell death, how it gets unregulated in response to different intra and extracellular stressors, various forms of unregulated cell death, their interplay and their role in pathogenesis of Alzheimer's Disease in both human and experimental models of AD. Further we plan to explore the correlation of both amyloid-beta and Tau with neuronal loss as seen in AD.

How neurons die in Alzheimer's disease: Implications for neuroinflammation

Despite the long-standing observation of vast neuronal loss in Alzheimer's disease (AD) our understanding of how and when neurons are eliminated is incomplete. While previous investigation has focused on apoptosis, several novel forms of cell death (i.e. necroptosis, parthanatos, ferroptosis, cuproptosis) have emerged that require further investigation. This review aims to collect evidence for different modes of neuronal cell death in AD and to also discuss how these different forms of cell death may impact the neuroinflammatory environment that prevails in the AD brain. Improved understanding of how neurons die may help to delineate disease pathogenesis, provide insights toward treatment, and aid in the development of improved animal models of AD.

Current and Near-Future Treatment of Alzheimer's Disease

Recent findings have improved our understanding of the multifactorial nature of AD. While in early asymptomatic stages of AD, increased amyloid-β synthesis and tau hyperphosphorylation play a key role, while in the latter stages of the disease, numerous dysfunctions of homeostatic mechanisms in neurons, glial cells, and cerebrovascular endothelium determine the rate of progression of clinical symptoms. The main driving forces of advanced neurodegeneration include increased inflammatory reactions in neurons and glial cells, oxidative stress, deficiencies in neurotrophic growth and regenerative capacity of neurons, brain insulin resistance with disturbed metabolism in neurons, or reduction of the activity of the Wnt-β catenin pathway, which should integrate the homeostatic mechanisms of brain tissue. In order to more effectively inhibit the progress of neurodegeneration, combination therapies consisting of drugs that rectify several above-mentioned dysfunctions should be used. It should be noted that many widely-used drugs from various pharmacological groups, "in addition" to the main therapeutic indications, have a beneficial effect on neurodegeneration and may be introduced into clinical practice in combination therapy of AD. There is hope that complex treatment will effectively inhibit the progression of AD and turn it into a slowly progressing chronic disease. Moreover, as the mechanisms of bidirectional communication between the brain and microbiota are better understood, it is expected that these pathways will be harnessed to provide novel methods to enhance health and treat AD.

MST1 mediates neuronal loss and cognitive deficits: A novel therapeutic target for Alzheimer's disease

Alzheimer's disease (AD) is the most prevalent form of dementia in the old adult and characterized by progressive cognitive decline and neuronal damage. The mammalian Ste20-like kinase1/2 (MST1/2) is a core component in Hippo signaling, which regulates neural stem cell proliferation, neuronal death and neuroinflammation. However, whether MST1/2 is involved in the occurrence and development of AD remains unknown. In this study we reported that the activity of MST1 was increased with Aβ accumulation in the hippocampus of 5xFAD mice. Overexpression of MST1 induced AD-like phenotype in normal mice and accelerated cognitive decline, synaptic plasticity damage and neuronal apoptosis in 2-month-old 5xFAD mice, but did not significantly affect Aβ levels. Mechanistically, MST1 associated with p53 and promoted neuronal apoptosis by phosphorylation and activation of p53, while p53 knockout largely reversed MST1-induced AD-like cognitive deficits. Importantly, either genetic knockdown or chemical inactivation of MST1 could significantly improve cognitive deficits and neuronal apoptosis in 7-month-old 5xFAD mice. Our results support the idea that MST1-mediated neuronal apoptosis is an essential mechanism of cognitive deficits and neuronal loss for AD, and manipulating the MST1 activity as a potential strategy will shed light on clinical treatment for AD or other diseases caused by neuronal injury.

Mechanotransduction: Exploring New Therapeutic Avenues in Central Nervous System Pathology

Cells are continuously exposed to physical forces and the central nervous system (CNS) is no exception. Cells dynamically adapt their behavior and remodel the surrounding environment in response to forces. The importance of mechanotransduction in the CNS is illustrated by exploring its role in CNS pathology development and progression. The crosstalk between the biochemical and biophysical components of the extracellular matrix (ECM) are here described, considering the recent explosion of literature demonstrating the powerful influence of biophysical stimuli like density, rigidity and geometry of the ECM on cell behavior. This review aims at integrating mechanical properties into our understanding of the molecular basis of CNS disease. The mechanisms that mediate mechanotransduction events, like integrin, Rho/ROCK and matrix metalloproteinases signaling pathways are revised. Analysis of CNS pathologies in this context has revealed that a wide range of neurological diseases share as hallmarks alterations of the tissue mechanical properties. Therefore, it is our belief that the understanding of CNS mechanotransduction pathways may lead to the development of improved medical devices and diagnostic methods as well as new therapeutic targets and strategies for CNS repair.

Role of Intracellular Amyloid β as Pathway Modulator, Biomarker, and Therapy Target

The β- and γ-secretase-driven cleavage of the amyloid precursor protein (APP) gives rise to the amyloid β peptide, which is believed to be the main driver of neurodegeneration in Alzheimer’s disease (AD). As it is prominently detectable in extracellular plaques in post-mortem AD brain samples, research in recent decades focused on the pathological role of extracellular amyloid β aggregation, widely neglecting the potential meaning of very early generation of amyloid β inside the cell. In the last few years, the importance of intracellular amyloid β (iAβ) as a strong player in neurodegeneration has been indicated by a rising number of studies. In this review, iAβ is highlighted as a crucial APP cleavage fragment, able to manipulate intracellular pathways and foster neurodegeneration. We demonstrate its relevance as a pathological marker and shed light on initial studies aiming to modulate iAβ through pharmacological treatment, which has been shown to have beneficial effects on cognitive properties in animal models. Finally, we display the relevance of viral infections on iAβ generation and point out future directions urgently needed to manifest the potential relevance of iAβ in Alzheimer’s disease.

Oncogenic Pathways in Neurodegenerative Diseases

Cancer and neurodegenerative diseases are two of the leading causes of premature death in modern societies. Their incidence continues to increase, and in the near future, it is believed that cancer will kill more than 20 million people per year, and neurodegenerative diseases, due to the aging of the world population, will double their prevalence. The onset and the progression of both diseases are defined by dysregulation of the same molecular signaling pathways. However, whereas in cancer, these alterations lead to cell survival and proliferation, neurodegenerative diseases trigger cell death and apoptosis. The study of the mechanisms underlying these opposite final responses to the same molecular trigger is key to providing a better understanding of the diseases and finding more accurate treatments. Here, we review the ten most common signaling pathways altered in cancer and analyze them in the context of different neurodegenerative diseases such as Alzheimer's (AD), Parkinson's (PD), and Huntington's (HD) diseases.

Small molecule LATS kinase inhibitors block the Hippo signaling pathway and promote cell growth under 3D culture conditions

Although 3D cell culture models are considered to reflect the physiological microenvironment and exhibit high concordance with in vivo conditions, one disadvantage has been that cell proliferation is slower in 3D culture as compared to 2D culture. However, the signaling differences that lead to this slower proliferation are unclear. Here, we conducted a cell-based high-throughput screening study and identified novel small molecules that promote cell proliferation, particularly under 3D conditions. We found that one of these molecules, designated GA-017, increases the number and size of spheroids of various cell-types in both scaffold-based and scaffold-independent cultures. In addition, GA-017 also enhances the ex vivo formation of mouse intestinal organoids. Importantly, we demonstrate that GA-017 inhibits the serine/threonine protein kinases large tumor suppressor kinase 1/2, which phosphorylate Yes-associated protein and transcriptional coactivator with PDZ-binding motif , key effectors of the growth- and proliferation-regulating Hippo signaling pathway. We showed that GA-017 facilitates the growth of spheroids and organoids by stabilizing and translocating Yes-associated protein and transcriptional coactivator with PDZ-binding motif into the cell nucleus. Another chemical analog of GA-017 obtained in this screening also exhibited similar activities and functions. We conclude that experiments with these small molecule large tumor suppressor kinase inhibitors will contribute to further development of efficient 3D culture systems for the ex vivo expansion of spheroids and organoids.

Does Chronic Sleep Fragmentation Lead to Alzheimer's Disease in Young Wild-Type Mice?

Chronic sleep insufficiency is becoming a common issue in the young population nowadays, mostly due to life habits and work stress. Studies in animal models of neurological diseases reported that it would accelerate neurodegeneration progression and exacerbate interstitial metabolic waste accumulation in the brain. In this paper, we study whether chronic sleep insufficiency leads to neurodegenerative diseases in young wild-type animals without a genetic pre-disposition. To this aim, we modeled chronic sleep fragmentation (SF) in young wild-type mice. We detected pathological hyperphosphorylated-tau (Ser396/Tau5) and gliosis in the SF hippocampus. ¹⁸F-labeled fluorodeoxyglucose positron emission tomography scan (¹⁸F-FDG-PET) further revealed a significant increase in brain glucose metabolism, especially in the hypothalamus, hippocampus and amygdala. Hippocampal RNAseq indicated that immunological and inflammatory pathways were significantly altered in 1.5-month SF mice. More interestingly, differential expression gene lists from stress mouse models showed differential expression patterns between 1.5-month SF and control mice, while Alzheimer's disease, normal aging, and APOEε4 mutation mouse models did not exhibit any significant pattern. In summary, 1.5-month sleep fragmentation could generate AD-like pathological changes including tauopathy and gliosis, mainly linked to stress, as the incremented glucose metabolism observed with PET imaging suggested. Further investigation will show whether SF could eventually lead to chronic neurodegeneration if the stress condition is prolonged in time.

The Potential of Ferroptosis-Targeting Therapies for Alzheimer's Disease: From Mechanism to Transcriptomic Analysis

Alzheimer’s disease (AD), the most common form of dementia, currently affects 40–50 million people worldwide. Despite the extensive research into amyloid β (Aβ) deposition and tau protein hyperphosphorylation (p-tau), an effective treatment to stop or slow down the progression of neurodegeneration is missing. Emerging evidence suggests that ferroptosis, an iron-dependent and lipid peroxidation-driven type of programmed cell death, contributes to neurodegeneration in AD. Therefore, how to intervene against ferroptosis in the context of AD has become one of the questions addressed by studies aiming to develop novel therapeutic strategies. However, the underlying molecular mechanism of ferroptosis in AD, when ferroptosis occurs in the disease course, and which ferroptosis-related genes are differentially expressed in AD remains to be established. In this review, we summarize the current knowledge on cell mechanisms involved in ferroptosis, we discuss how these processes relate to AD, and we analyze which ferroptosis-related genes are differentially expressed in AD brain dependant on cell type, disease progression and gender. In addition, we point out the existing targets for therapeutic options to prevent ferroptosis in AD. Future studies should focus on developing new tools able to demonstrate where and when cells undergo ferroptosis in AD brain and build more translatable AD models for identifying anti-ferroptotic agents able to slow down neurodegeneration.

Mechanosensing and the Hippo Pathway in Microglia: A Potential Link to Alzheimer's Disease Pathogenesis?

The activation of microglia, the inflammatory cells of the central nervous system (CNS), has been linked to the pathogenesis of Alzheimer’s disease and other neurodegenerative diseases. How microglia sense the changing brain environment, in order to respond appropriately, is still being elucidated. Microglia are able to sense and respond to the mechanical properties of their microenvironment, and the physical and molecular pathways underlying this mechanosensing/mechanotransduction in microglia have recently been investigated. The Hippo pathway functions through mechanosensing and subsequent protein kinase cascades, and is critical for neuronal development and many other cellular processes. In this review, we examine evidence for the potential involvement of Hippo pathway components specifically in microglia in the pathogenesis of Alzheimer’s disease. We suggest that the Hippo pathway is worth investigating as a mechanosensing pathway in microglia, and could be one potential therapeutic target pathway for preventing microglial-induced neurodegeneration in AD.

Willin/FRMD6: A Multi-Functional Neuronal Protein Associated with Alzheimer's Disease

The FERM domain-containing protein 6 (FRMD6), also known as Willin, is an upstream regulator of Hippo signaling that has recently been shown to modulate actin cytoskeleton dynamics and mechanical phenotype of neuronal cells through ERK signaling. Physiological functions of Willin/FRMD6 in the nervous system include neuronal differentiation, myelination, nerve injury repair, and vesicle exocytosis. The newly established neuronal role of Willin/FRMD6 is of particular interest given the mounting evidence suggesting a role for Willin/FRMD6 in Alzheimer's disease (AD), including a series of genome wide association studies that position Willin/FRMD6 as a novel AD risk gene. Here we describe recent findings regarding the role of Willin/FRMD6 in the nervous system and its actions in cellular perturbations related to the pathogenesis of AD.

Synthesis of D-π-A type benzothiazole-pyridinium salt composite and its application as photo-degradation agent for amyloid fibrils

We have synthesized a cyan fluorescent benzothiazole-pyridinium salt composite based on D-π-A architecture. This salt was found to work as not only a two- and three-photon excitable fluorophore but also a degradation agent against amyloid fibrils under LED irradiation conditions.

HMGB1 signaling phosphorylates Ku70 and impairs DNA damage repair in Alzheimer's disease pathology

DNA damage is increased in Alzheimer's disease (AD), while the underlying mechanisms are unknown. Here, we employ comprehensive phosphoproteome analysis, and identify abnormal phosphorylation of 70 kDa subunit of Ku antigen (Ku70) at Ser77/78, which prevents Ku70-DNA interaction, in human AD postmortem brains. The abnormal phosphorylation inhibits accumulation of Ku70 to the foci of DNA double strand break (DSB), impairs DNA damage repair and eventually causes transcriptional repression-induced atypical cell death (TRIAD). Cells under TRIAD necrosis reveal senescence phenotypes. Extracellular high mobility group box 1 (HMGB1) protein, which is released from necrotic or hyper-activated neurons in AD, binds to toll-like receptor 4 (TLR4) of neighboring neurons, and activates protein kinase C alpha (PKCα) that executes Ku70 phosphorylation at Ser77/78. Administration of human monoclonal anti-HMGB1 antibody to post-symptomatic AD model mice decreases neuronal DSBs, suppresses secondary TRIAD necrosis of neurons, prevents escalation of neurodegeneration, and ameliorates cognitive symptoms. TRIAD shares multiple features with senescence. These results discover the HMGB1-Ku70 axis that accounts for the increase of neuronal DNA damage and secondary enhancement of TRIAD, the cell death phenotype of senescence, in AD.

TNF-α-dependent neuronal necroptosis regulated in Alzheimer's disease by coordination of RIPK1-p62 complex with autophagic UVRAG

Background: Neuronal death is a major hallmark of Alzheimer's disease (AD). Necroptosis, as a programmed necrotic process, is activated in AD. However, what signals and factors initiate necroptosis in AD is largely unknown. Methods: We examined the expression levels of critical molecules in necroptotic signaling pathway by immunohistochemistry (IHC) staining and immunoblotting using brain tissues from AD patients and AD mouse models of APP/PS1 and 5×FAD. We performed brain stereotaxic injection with recombinant TNF-α, anti-TNFR1 neutralizing antibody or AAV-mediated gene expression and knockdown in APP/PS1 mice. For in vitro studies, we used TNF-α combined with zVAD-fmk and Smac mimetic to establish neuronal necroptosis models and utilized pharmacological or molecular biological approaches to study the signaling pathways. Results: We find that activated neuronal necroptosis is dependent on upstream TNF-α/TNFR1 signaling in both neuronal cell cultures and AD mouse models. Upon TNF-α stimulation, accumulated p62 recruits RIPK1 and induces its self-oligomerization, and activates downstream RIPK1/RIPK3/MLKL cascade, leading to neuronal necroptosis. Ectopic accumulation of p62 is caused by impaired autophagy flux, which is mediated by UVRAG downregulation during the TNF-α-promoted necroptosis. Notably, UVRAG overexpression inhibits neuronal necroptosis in cell and mouse models of AD. Conclusions: We identify a finely controlled regulation of neuronal necroptosis in AD by coordinated TNF-α signaling, RIPK1/3 activity and autophagy machinery. Strategies that could fine-tune necroptosis and autophagy may bring in promising therapeutics for AD.

YAP prevents premature senescence of astrocytes and cognitive decline of Alzheimer's disease through regulating CDK6 signaling

Senescent astrocytes accumulate with aging and contribute to brain dysfunction and diseases such as Alzheimer's disease (AD), however, the mechanisms underlying the senescence of astrocytes during aging remain unclear. In the present study, we found that Yes‐associated Protein (YAP) was downregulated and inactivated in hippocampal astrocytes of aging mice and AD model mice, as well as in D‐galactose and paraquat‐induced senescent astrocytes, in a Hippo pathway‐dependent manner. Conditional knockout of YAP in astrocytes significantly promoted premature senescence of astrocytes, including reduction of cell proliferation, hypertrophic morphology, increase in senescence‐associated β‐galactosidase activity, and upregulation of several senescence‐associated genes such as p16, p53 and NF‐κB, and downregulation of Lamin B1. Further exploration of the underlying mechanism revealed that the expression of cyclin‐dependent kinase 6 (CDK6) was decreased in YAP knockout astrocytes in vivo and in vitro, and ectopic overexpression of CDK6 partially rescued YAP knockout‐induced senescence of astrocytes. Finally, activation of YAP signaling by XMU‐MP‐1 (an inhibitor of Hippo kinase MST1/2) partially rescued the senescence of astrocytes and improved the cognitive function of AD model mice and aging mice. Taken together, our studies identified unrecognized functions of YAP‐CDK6 pathway in preventing astrocytic senescence in vitro and in vivo, which may provide further insights and new targets for delaying brain aging and aging‐related neurodegenerative diseases such as AD.

Altered Gene Expression Profiles in Neural Stem Cells Derived from Duchenne Muscular Dystrophy Patients with Intellectual Disability

Intellectual disability (ID) is a neurodevelopmental disorder defined by below-average intelligence (intelligence quotient of <70) accompanied by adaptive behavior deficits. Defects in the functions of neural stem cells during brain development are closely linked to the pathogenesis of ID. To understand the molecular etiology of ID, we examined neural stem cells from individuals with Duchenne muscular dystrophy (DMD), a genetic disorder in which approximately one-third of the patients exhibit ID. In this study, we generated induced pluripotent stem cells from peripheral blood mononuclear cells from a normal individual and DMD patients with and without ID to identify ID-specific functional and molecular abnormalities. We found defects in neural ectoderm formation in the group of DMD patients with ID. Our transcriptome analysis of patient-derived neural stem cells revealed altered expression of genes related to the hippo signaling pathway and neuroactive ligand-receptor interaction, implicating these in the pathogenesis of ID in patients with DMD.

Hepta-Histidine Inhibits Tau Aggregation

Tau aggregation is a central hallmark of tauopathies such as frontotemporal lobar degeneration and progressive supranuclear palsy as well as of Alzheimer's disease, and it has been a target for therapeutic development. Herein, we unexpectedly found that hepta-histidine (7H), an inhibitor of the interaction between Ku70 and Huntingtin proteins, suppresses aggregation of Tau-R3 peptides in vitro. Addition of the trans-activator of transcription (TAT) sequence (YGRKKRRQRRR) derived from the TAT protein to 7H increased its permeability into cells, and TAT-7H treatment of iPS cell-derived neurons carrying Tau or APP mutations suppressed Tau phosphorylation. These results indicate that 7H is a promising lead compound for developing anti-aggregation drugs against Tau-related neurodegenerative diseases including Alzheimer's disease (AD).

Prediction and verification of the AD-FTLD common pathomechanism based on dynamic molecular network analysis

Multiple gene mutations cause familial frontotemporal lobar degeneration (FTLD) while no single gene mutations exists in sporadic FTLD. Various proteins aggregate in variable regions of the brain, leading to multiple pathological and clinical prototypes. The heterogeneity of FTLD could be one of the reasons preventing development of disease-modifying therapy. We newly develop a mathematical method to analyze chronological changes of PPI networks with sequential big data from comprehensive phosphoproteome of four FTLD knock-in (KI) mouse models (PGRNR504X-KI, TDP43N267S-KI, VCPT262A-KI and CHMP2BQ165X-KI mice) together with four transgenic mouse models of Alzheimer's disease (AD) and with APPKM670/671NL-KI mice at multiple time points. The new method reveals the common core pathological network across FTLD and AD, which is shared by mouse models and human postmortem brains. Based on the prediction, we performed therapeutic intervention of the FTLD models, and confirmed amelioration of pathologies and symptoms of four FTLD mouse models by interruption of the core molecule HMGB1, verifying the new mathematical method to predict dynamic molecular networks.

Transcriptional Modulation of the Hippo Signaling Pathway by Drugs Used to Treat Bipolar Disorder and Schizophrenia

Recent reports suggest a link between positive regulation of the Hippo pathway with bipolar disorder (BD), and the Hippo pathway is known to interact with multiple other signaling pathways previously associated with BD and other psychiatric disorders. In this study, neuronal-like NT2 cells were treated with amisulpride (10 µM), aripiprazole (0.1 µM), clozapine (10 µM), lamotrigine (50 µM), lithium (2.5 mM), quetiapine (50 µM), risperidone (0.1 µM), valproate (0.5 mM), or vehicle control for 24 h. Genome-wide mRNA expression was quantified and analyzed using gene set enrichment analysis (GSEA), with genes belonging to Hippo, Wnt, Notch, TGF- β, and Hedgehog retrieved from the KEGG database. Five of the eight drugs downregulated the genes of the Hippo pathway and modulated several genes involved in the interacting pathways. We speculate that the regulation of these genes, especially by aripiprazole, clozapine, and quetiapine, results in a reduction of MAPK and NFκB pro-inflammatory signaling through modulation of Hippo, Wnt, and TGF-β pathways. We also employed connectivity map analysis to identify compounds that act on these pathways in a similar manner to the known psychiatric drugs. Thirty-six compounds were identified. The presence of antidepressants and antipsychotics validates our approach and reveals possible new targets for drug repurposing.

Multi-Redox Active Carbons and Hydrocarbons: Control of their Redox Properties and Potential Applications

Precise control over redox properties is essential for high-performance organic electronic devices such as organic batteries, electrochromic devices, and information storage devices. In this context, multi-redox active carbons and hydrocarbons, represented as C_x H_y molecules (x≥1, y≥0), are highly sought after, because they can switch between multiple redox states. Herein, we outline the redox properties of C_x H_y molecules as solutes and adsorbed species. Furthermore, the limitations of evaluating their redox properties and the possible solutions are summarized. Additionally, the theoretical capacity (mAh/g) and gravimetric energy density (Wh/kg) of secondary batteries were estimated based on the redox properties of 185 C_x H_y molecules, which have primarily been reported in the last decade. Among them, seven C_x H_y molecules were found to have the potential to surpass the energy density of LiNi_0.6 Mn_0.2 Co_0.2 O₂ /graphite batteries. The use of C_x H_y molecules in multielectrochromic devices and multi-bit memory is also explained. We believe that this review will encourage further utilization of C_x H_y molecules thereby promoting its applications in organic electronic devices.

DNA damage in embryonic neural stem cell determines FTLDs' fate via early-stage neuronal necrosis

The early-stage pathologies of frontotemporal lobal degeneration (FTLD) remain largely unknown. In VCP^T262A-KI mice carrying VCP gene mutation linked to FTLD, insufficient DNA damage repair in neural stem/progenitor cells (NSCs) activated DNA-PK and CDK1 that disabled MCM3 essential for the G1/S cell cycle transition. Abnormal neural exit produced neurons carrying over unrepaired DNA damage and induced early-stage transcriptional repression-induced atypical cell death (TRIAD) necrosis accompanied by the specific markers pSer46-MARCKS and YAP. In utero gene therapy expressing normal VCP or non-phosphorylated mutant MCM3 rescued DNA damage, neuronal necrosis, cognitive function, and TDP43 aggregation in adult neurons of VCP^T262A-KI mice, whereas similar therapy in adulthood was less effective. The similar early-stage neuronal necrosis was detected in PGRN^R504X-KI, CHMP2B^Q165X-KI, and TDP^N267S-KI mice, and blocked by embryonic treatment with AAV-non-phospho-MCM3. Moreover, YAP-dependent necrosis occurred in neurons of human FTLD patients, and consistently pSer46-MARCKS was increased in cerebrospinal fluid (CSF) and serum of these patients. Collectively, developmental stress followed by early-stage neuronal necrosis is a potential target for therapeutics and one of the earliest general biomarkers for FTLD.