New insights into the genetic etiology of Alzheimer’s disease and related dementias

Artículo escrito por un elevado número de autores, solo se referencia el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMCharacterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 alleleThis research was conducted using the UKBB resource (application number 61054). This work was funded by a grant (EADB) from the EU Joint Programme – Neurodegenerative Disease Research. INSERM UMR1167 is also funded by the INSERM, Institut Pasteur de Lille, Lille Métropole Communauté Urbaine and French government’s LABEX DISTALZ program (development of innovative strategies for a transdisciplinary approach to AD). Full consortium acknowledgements and funding are in the Supplementary Note

Convergent genetic and expression data implicate immunity in Alzheimer's disease

© 2015, Elsevier Inc. All rights reserved. Background: Late-onset Alzheimer's disease (AD) is heritable with 20 genes showing genome-wide association in the International Genomics of Alzheimer's Project (IGAP). To identify the biology underlying the disease, we extended these genetic data in a pathway analysis. Methods: The ALIGATOR and GSEA algorithms were used in the IGAP data to identify associated functional pathways and correlated gene expression networks in human brain. Results: ALIGATOR identified an excess of curated biological pathways showing enrichment of association. Enriched areas of biology included the immune response (P = 3.27 × 10-12 after multiple testing correction for pathways), regulation of endocytosis (P = 1.31 × 10-11), cholesterol transport (P = 2.96 × 10-9), and proteasome-ubiquitin activity (P = 1.34 × 10-6). Correlated gene expression analysis identified four significant network modules, all related to the immune response (corrected P =.002-.05). Conclusions: The immune response, regulation of endocytosis, cholesterol transport, and protein ubiquitination represent prime targets for AD therapeutics.Medical Research Council, Alzheimer’s Research UK, and theWelsh Assembly Government. ADGC and CHARGE were supported by the National Institutes of Health, National Institute on Aging (NIH-NIA). CHARGE was also supported by Erasmus Medical Center and Erasmus University. IGAP was funded by the French National Foundation on Alzheimer’s Disease and Related Disorders, the Centre National de Genotypage and the Institut Pasteur de Lille, Inserm, FRC (Fondation pour la Recherche sur le Cerveau), and Rotary. This work has been developed and supported by the LABEX (Laboratory of Excellence Program Investment for the Future) DISTALZ grant (Development of Innovative Strategies for a Transdisciplinary approach to ALZheimer’s disease).Peer Reviewe

Multiancestry analysis of the HLA locus in Alzheimer's and Parkinson's diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereAcross multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson's disease (PD) and Alzheimer's disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenuesThis work was supported by the Michael J. Fox Foundation grant MJFF-020161 (E.M., Z.G.-O.), NIH and National Institute of Aging grants AG060747 (M.D.G.), AG066206 (Z.H.), AG066515 (Z.H., M.D.G.), the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie (grant agreement No. 890650, Y.L.G.), the Alzheimer’s Association (AARF-20-683984, M.E.B.), and the Iqbal Farrukh and Asad Jamal Fund, a grant from the EU Joint Programme—Neurodegenerative Disease Research (European Alzheimer DNA BioBank, EADB; JPND), the Japan Agency for Medical Research and Development JP21dk0207045 (T.I.), JP21dk020704 (K.O., S.N.), JP21km040550 (K.O.), the Einstein Center for Neurosciences in Berlin (S.M.Y.), the Swedish Research Council (#2018-02532, H.Z.), the European Research Council (#681712, H.Z.), and the Swedish State Support for Clinical Research (#ALFGBG-720931, H.Z.). Inserm UMR1167 is also funded by the Inserm, Institut Pasteur de Lille, Lille Métropole Communauté Urbaine, and the French government’s LABEX DISTALZ program (development of innovative strategies for a transdisciplinary approach to AD). Additional funders of individual investigators and institutions who contributed to data collection and genotyping are provided in SI Appendi

Herpes simplex virus type 2 infection induces AD-like neurodegeneration markers in human neuroblastoma cells

© 2015 Elsevier Inc. Herpes simplex virus (HSV) types 1 and 2 are neurotropic viruses that establish lifelong latent infections in neurons. Mounting evidence suggests that HSV-1 infection is involved in the pathogenesis of Alzheimer's disease (AD). The relationships between other herpesvirus infections and events associated with neurodegeneration have not, however, been extensively studied. The present work reports that HSV-2 infection leads to the strong accumulation of hyperphosphorylated tau and the amyloid-β peptides Aβ40 and Aβ42 (all major pathological hallmarks of AD) in human SK-N-MC neuroblastoma cells. Infection is also associated with a marked reduction in the amount of Aβ40 secreted and in the proteolytic fragments of the amyloid-β precursor protein (APP) (secreted APPα and the α-C-terminal fragment). These results indicate that HSV-2 infection inhibits the nonamyloidogenic pathway of APP processing and impairs Aβ secretion in these cells. In addition, HSV-2 induces the accumulation of intracellular autophagic compartments containing Aβ due to a failure in the late stages of autophagy. To our knowledge, this is the first report to show that HSV-2 infection strongly alters the tau phosphorylation state, APP processing, and autophagic process in human neuroblastoma cells, leading to the appearance of AD-like neurodegeneration markers.Ministerio de Economía y Competitividad (SAF2010-15558; URL: http://www.mineco.gob.es/portal/site/mineco) and Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas CIBERNED (PI2010/09-8; URL: http://www.ciberned.es).Peer Reviewe

The lysosome system is severely impaired in a cellular model of neurodegeneration induced by HSV-1 and oxidative stress

The causal agent(s) and molecular mechanisms of Alzheimer's disease (AD) remain unclear. Mounting evidence suggests that herpes simplex virus type 1 (HSV-1) infection is involved in the AD pathogenesis. Oxidative stress (OS) may also be crucial in the AD development. Our group previously reported that both HSV-1 and OS trigger the appearance of AD-type neurodegeneration markers. The main aim of the present study was to identify the mechanisms involved in this triggering. Expression studies revealed the involvement of a set of OS-regulated genes in HSV-1-infected cells and in cells harboring the Swedish mutation of the amyloid beta precursor protein gene. Functional annotation of these genes revealed the lysosome system to be impaired, suggesting that the interaction of OS with both HSV-1 and amyloid beta precursor protein mutations affects lysosomal function. Functional studies revealed HSV-1 infection and OS to increase the lysosome load, reduce the activity of lysosomal hydrolases, affect cathepsin maturation, and inhibit the endocytosis-mediated degradation of the epidermal growth factor receptor. These findings suggest alterations in the lysosome system to be involved in different forms of ADHeniike Kristen is recipient of a UAM-CSIC International Excellence Campus research contract.Institutional grants from the Fundación Ramón Areces and Banco de Santander to the CBMSO are also acknowledged. This work was supported by the Spanish Ministerio de Ciencia e Innovación (SAF2014-53954-R

Mendelian randomisation confirms the role of Y-chromosome loss in Alzheimer’s disease aetiopathogenesis in men

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereMosaic loss of chromosome Y (mLOY) is a common ageing-related somatic event and has been previously associated with Alzheimer’s disease (AD). However, mLOY estimation from genotype microarray data only reflects the mLOY degree of subjects at the moment of DNA sampling. Therefore, mLOY phenotype associations with AD can be severely age-confounded in the context of genome-wide association studies. Here, we applied Mendelian randomisation to construct an age-independent mLOY polygenic risk score (mloy-PRS) using 114 autosomal variants. The mloy-PRS instrument was associated with an 80% increase in mLOY risk per standard deviation unit (p = 4.22 × 10−20) and was orthogonal with age. We found that a higher genetic risk for mLOY was associated with faster progression to AD in men with mild cognitive impairment (hazard ratio (HR) = 1.23, p = 0.01). Importantly, mloy-PRS had no effect on AD conversion or risk in the female group, suggesting that these associations are caused by the inherent loss of the Y chromosome. Additionally, the blood mLOY phenotype in men was associated with increased cerebrospinal fluid levels of total tau and phosphorylated tau181 in subjects with mild cognitive impairment and dementia. Our results strongly suggest that mLOY is involved in AD pathogenesi

Herpes simplex virus type 1 induces AD-like neurodegeneration markers in human progenitor and differentiated ReNcell VM cells

An increasing body of evidence strongly suggests that infections or reactivations of herpes simplex virus type 1 (HSV-1) may be closely linked to Alzheimer’s disease (AD). Promising results have been obtained using cell and animal models of HSV-1 infection, contributing to the understanding of the molecular mechanisms linking HSV-1 infection and AD neurodegeneration. ReNcell VM is a human neural stem cell line that has been used as a model system to study the impact of various infectious agents on the central nervous system. In this study, we demonstrate the suitability of the ReNcell VM cell line for developing a new in vitro model of HSV-1 infection. By following standard differentiation protocols, we were able to derive various nervous cell types, including neurons, astrocytes, and oligodendrocytes, from neural precursors. Additionally, we demonstrated the susceptibility of ReNcell VM cells, including precursor and differentiated cells, to HSV-1 infection and subsequent viral-induced AD-like neurodegeneration. Our findings support the use of this cell line to generate a new research platform for investigating AD neuropathology and its most significant risk factors, which may lead to important discoveries in the context of this highly impactful diseaseThis work was funded by the Spanish Ministerio de Ciencia e Innovación (PID2020-113921RBI00

MAPT H1 haplotype is associated with late-onset Alzheimer's disease risk in APOE ε 4 noncarriers: Results from the dementia genetics Spanish consortium

The MAPT H1 haplotype has been linked to several disorders, but its relationship with Alzheimer's disease (AD) remains controversial. A rare variant in MAPT (p.A152T) has been linked with frontotemporal dementia (FTD) and AD. We genotyped H1/H2 and p.A152T MAPT in 11,572 subjects from Spain (4,327 AD, 563 FTD, 648 Parkinson's disease (PD), 84 progressive supranuclear palsy (PSP), and 5,950 healthy controls). Additionally, we included 101 individuals from 21 families with genetic FTD. MAPT p.A152T was borderline significantly associated with FTD [odds ratio (OR)=2.03; p=0.063], but not with AD. MAPT H1 haplotype was associated with AD risk (OR=1.12; p=0.0005). Stratification analysis showed that this association was mainly driven by APOE ε4 noncarriers (OR=1.14; p=0.0025). MAPT H1 was also associated with risk for PD (OR=1.30; p=0.0003) and PSP (OR=3.18; p=8.59 × 10-8) but not FTD. Our results suggest that the MAPT H1 haplotype increases the risk of PD, PSP, and non-APOE ε4 AD.Spanish Ministry of Science and Innovation SAF 2006-10126 (2006–2009) and SAF2010-22329-C02-01 (2011–2013) to P.P and by the UTE project FIMA to P.P. Grants from the Ministry of Science (SAF2010-15558) and CIBERNED. Agust´ın Ruiz is supported by grant PI13/02434 (Acción Estratégica en Salud. Instituto de Salud Carlos III. Ministerio de Economía y Competitividad, Spain). Grant: Consolider (CSD2010-00045).Peer Reviewe

Matrix metalloproteinase 14 regulates HSV-1 infection in neuroblastoma cells

Growing evidence supports that chronic or latent infection of the central nervous system might be implicated in Alzheimer's disease (AD). Among them, Herpes simplex virus type 1 (HSV-1) has emerged as a major factor in the etiology of the disease. Our group is devoted to the study of the relationship among HSV-1, oxidative stress (OS) and neurodegeneration. We have found that HSV-1 induces the main neuropathological hallmarks of AD, including the accumulation of intracellular amyloid beta (Aβ), hyperphosphorylated tau protein and autophagic vesicles, that OS exacerbates these effects, and that matrix metalloproteinase 14 (MMP-14) participates in the alterations induced by OS. In this work, we focused on the role of MMP-14 in the degenerative markers raised by HSV-1 infection. Interestingly, we found that MMP-14 blockage is a potent inhibitor of HSV-1 infection efficiency, that also reduces the degeneration markers, accumulation of Aβ and hyperphosphorylated tau, induced by the virus. Our results point to MMP-14 as a potent antiviral target to control HSV-1 infection and its associated neurodegenerative effectsThis work was supported by the Ministerio de Ciencia, Innovación y Universidades (SAF2017-85747-R

Caspase-1 genetic variation is not associated with Alzheimer's disease risk

BACKGROUND: Interleukin (IL)-1beta is a potent proinflammatory cytokine markedly overexpressed in the brains of patients with Alzheimer's disease (AD), and also involved in development of atherosclerosis and coronary artery disease. Caspase-1 (CASP1), formerly called IL-1beta converting enzyme (ICE), mediates the cleavage of the inactive precursor of IL-1beta into the biologically active form. CASP1 genetic variation (G+7/in6A, rs501192) has been associated with susceptibility to myocardial infarction and cardiovascular death risk. We examined the contribution of this gene to the susceptibility for AD. METHODS: We examined genetic variations of CASP1 by genotyping haplotype tagging SNPs (htSNPs) (rs501192, rs556205 and rs530537) in a group of 628 Spanish AD cases and 722 controls. RESULTS: There were no differences in the genotypic, allelic or haplotypic distributions between cases and controls in the overall analysis or after stratification by age, gender or APOE epsilon4 allele. CONCLUSION: Our negative findings in the Spanish population argue against the hypothesis that CASP1 genetic variations are causally related to AD risk