Changes in brain gene expression shared by scrapie and Alzheimer disease.
Ontology highlight
ABSTRACT:
SUBMITTER: Duguid JR
PROVIDER: S-EPMC298037 | biostudies-other | 1989 Sep
REPOSITORIES: biostudies-other
Publications
Changes in brain gene expression shared by scrapie and Alzheimer disease.
Duguid J R JR Bohmont C W CW Liu N G NG Tourtellotte W W WW
Proceedings of the National Academy of Sciences of the United States of America 19890901 18
We have isolated two recombinant cDNAs whose corresponding RNAs have an increased abundance in scrapie-infected hamster brain. DNA sequence analysis has shown that these two recombinants represent the genes for sulfated glycoprotein 2 and transferrin. The abundance of sulfated glycoprotein 2 RNA is increased in hippocampus from patients with Alzheimer disease and Pick disease, whereas transferrin RNA is not strongly modulated in these conditions. Expression of two previously identified scrapie-m ...[more]
Similar Datasets
Project description:Heat shock proteins (Hsp) perform cytoprotective functions such as apoptosis regulation and inflammatory response control. These proteins can also be secreted to the extracellular medium, acting as inflammatory mediators, and their chaperone activity permits correct folding of proteins and avoids the aggregation of anomalous isoforms. Several studies have proposed the implication of Hsp in prion diseases. We analysed the gene expression and protein distribution of different members of the Hsp27, Hsp70, and Hsp90 families in the central nervous system of sheep naturally infected with scrapie. Different expression profiles were observed in the areas analysed. Whereas changes in transcript levels were not observed in the cerebellum or medulla oblongata, a significant decrease in HSP27 and HSP90 was detected in the prefrontal cortex. In contrast, HSP73 was over-expressed in diencephalons of scrapie animals. Western blotting did not reveal significant differences in Hsp90 and Hsp70 protein expression between scrapie and control animals. Expression rates identified by real-time RT-PCR and western blotting were compared with the extent of classical scrapie lesions using stepwise regression. Changes in Hsp gene and protein expression were associated with prion protein deposition, gliosis and spongiosis rather than with apoptosis. Finally, immunohistochemistry revealed intense Hsp70 and Hsp90 immunolabelling in Purkinje cells of scrapie sheep. In contrast, controls displayed little or no staining in these cells. The observed differences in gene expression and protein distribution suggest that the heat shock proteins analysed play a role in the natural form of the disease.
| S-EPMC3037893 | biostudies-literature
Project description:ObjectiveRecent genome-wide association studies (GWAS) of late-onset Alzheimer disease (LOAD) identified 9 novel risk loci. Discovery of functional variants within genes at these loci is required to confirm their role in Alzheimer disease (AD). Single nucleotide polymorphisms that influence gene expression (eSNPs) constitute an important class of functional variants. We therefore investigated the influence of the novel LOAD risk loci on human brain gene expression.MethodsWe measured gene expression levels in the cerebellum and temporal cortex of autopsied AD subjects and those with other brain pathologies (∼400 total subjects). To determine whether any of the novel LOAD risk variants are eSNPs, we tested their cis-association with expression of 6 nearby LOAD candidate genes detectable in human brain (ABCA7, BIN1, CLU, MS4A4A, MS4A6A, PICALM) and an additional 13 genes ±100 kb of these SNPs. To identify additional eSNPs that influence brain gene expression levels of the novel candidate LOAD genes, we identified SNPs ±100 kb of their location and tested for cis-associations.ResultsCLU rs11136000 (p = 7.81 × 10(-4)) and MS4A4A rs2304933/rs2304935 (p = 1.48 × 10(-4)-1.86 × 10(-4)) significantly influence temporal cortex expression levels of these genes. The LOAD-protective CLU and risky MS4A4A locus alleles associate with higher brain levels of these genes. There are other cis-variants that significantly influence brain expression of CLU and ABCA7 (p = 4.01 × 10(-5)-9.09 × 10(-9)), some of which also associate with AD risk (p = 2.64 × 10(-2)-6.25 × 10(-5)).ConclusionsCLU and MS4A4A eSNPs may at least partly explain the LOAD risk association at these loci. CLU and ABCA7 may harbor additional strong eSNPs. These results have implications in the search for functional variants at the novel LOAD risk loci.
| S-EPMC3398432 | biostudies-literature
Project description:Unravel the mechanisms underlying brain aging and Alzheimer´s disease (AD) has been difficult because of complexity of the networks that drive these aging-related changes. Analysis of the gene expression in the brain is a valuable tool to study the function of the brain under normal and pathological conditions. Gene microarray technology allows massively parallel analysis of most genes expressed in a tissue, and therefore is an important research tool that potentially can provide the investigative power needed to address the complexity of brain aging and neurodegenerative processes. One of the reasons that account for the resistance of AD pathogenesis to analysis is that clinically normal subjects may exhibit considerable AD pathology, blurring criteria for distinguishing subjects with normal aging or AD. Here, we analyzed hippocampal and cortex frontal gene expression from 32 subjects separated in individuals presenting, 1) both pathologic and clinical AD (definitive AD); 2) AD pathology and normal clinic (pathologic AD); 3) cognitive impairment, without AD pathology (others dementias); and 4) no cognitive impairment, without AD pathology (normal individuals). Our results show that based on gene expression profile these individuals we could verify similarity between the definitive AD group and the group that only had AD-type pathology (pathologic AD). Specimens of hippocampus and cortex frontal used in this study were obtained at autopsy from 32 subjects. Neuropathology, specifically NFT and NP, was assessed in accordance to the Braak staging and CERAD scores, respectively. Based on pathologic and clinic criteria, subjects were categorized into four groups: 1) nine subjects with AD neuropathologic (Braak = IV / V / VI and CERAD ≠ 0) presenting cognitive impairment (CDR ≥ 1), termed “definitive AD” (dAD); 2) five subjects with AD neuropathologic (Braak = IV / V / VI and CERAD ≠ 0) and without cognitive impairment (CDR = 0), termed “pathologic AD” (pAD); 3) nine subjects without AD neuropathologic (Braak = 0 / I / II and CERAD ≠ C) presenting cognitive impairment (CDR ≥ 1), termed “other dementias” (OD); 4) - nine subjects without AD neuropathologic (Braak = 0 / I / II and CERAD ≠ C) and without cognitive impairment (CDR = 0), termed “normal” (N). RNA isolation and Amplification. From total RNA, a two-round linear amplification procedure (T7-based protocol) was carried out for all samples and for a pool of RNAs obtained from 15 distinct human cell lines used as reference. Labeled cDNA was generated in a reverse transcriptase reaction using amplified RNA (aRNA). Equal amounts of test and reference cDNA reverse color Cy-labeled aRNA targets were competitively hybridized against the cDNA probes in a customized cDNA platform with 4,608 ORESTES representing human genes. Dye-swap was performed for each sample as control for dye bias and used as replicate.
2013-01-11 | E-GEOD-13214 | biostudies-arrayexpress
Project description:Unravel the mechanisms underlying brain aging and Alzheimer´s disease (AD) has been difficult because of complexity of the networks that drive these aging-related changes. Analysis of the gene expression in the brain is a valuable tool to study the function of the brain under normal and pathological conditions. Gene microarray technology allows massively parallel analysis of most genes expressed in a tissue, and therefore is an important research tool that potentially can provide the investigative power needed to address the complexity of brain aging and neurodegenerative processes. One of the reasons that account for the resistance of AD pathogenesis to analysis is that clinically normal subjects may exhibit considerable AD pathology, blurring criteria for distinguishing subjects with normal aging or AD. Here, we analyzed hippocampal and cortex frontal gene expression from 32 subjects separated in individuals presenting, 1) both pathologic and clinical AD (definitive AD); 2) AD pathology and normal clinic (pathologic AD); 3) cognitive impairment, without AD pathology (others dementias); and 4) no cognitive impairment, without AD pathology (normal individuals). Our results show that based on gene expression profile these individuals we could verify similarity between the definitive AD group and the group that only had AD-type pathology (pathologic AD).
2013-01-11 | GSE13214 | GEO
Project description:Synaptic dysfunction and loss are core pathological features in Alzheimer disease (AD). In the vicinity of amyloid-? plaques in animal models, synaptic toxicity occurs and is associated with chronic activation of the phosphatase calcineurin (CN). Indeed, pharmacological inhibition of CN blocks amyloid-? synaptotoxicity. We therefore hypothesized that CN-mediated transcriptional changes may contribute to AD neuropathology and tested this by examining the impact of CN over-expression on neuronal gene expression in vivo. We found dramatic transcriptional down-regulation, especially of synaptic mRNAs, in neurons chronically exposed to CN activation. Importantly, the transcriptional profile parallels the changes in human AD tissue. Bioinformatics analyses suggest that both nuclear factor of activated T cells and numerous microRNAs may all be impacted by CN, and parallel findings are observed in AD. These data and analyses support the hypothesis that at least part of the synaptic failure characterizing AD may result from aberrant CN activation leading to down-regulation of synaptic genes, potentially via activation of specific transcription factors and expression of repressive microRNAs. OPEN PRACTICES:Open Science: This manuscript was awarded with the Open Materials Badge. For more information see: https://cos.io/our-services/open-science-badges/ Read the Editorial Highlight for this article on page 8.
| S-EPMC6181788 | biostudies-literature
Project description:The enigma that is Alzheimer's disease (AD) continues to present daunting challenges for effective therapeutic intervention. The lack of disease-modifying therapies may, in part, be attributable to the narrow research focus employed to understand this complex disease. Most studies into disease pathogenesis are based on a priori assumptions about the role of AD lesion-associated proteins such as amyloid-? and tau. However, the complex disease processes at work may not be amenable to single-target therapeutic approaches. Genome-wide expression studies provide an unbiased approach for investigating the pathogenesis of complex diseases like AD. A growing literature suggests a role for cerebrovascular contributions to the pathogenesis of AD. The objective of the current study is to examine human brain microvessels isolated from AD patients and controls by microarray analysis. Differentially expressed genes with more than 2-fold change are used for further data analysis. Gene ontology analysis and pathway analysis algorithms within GeneSpringGX are employed to understand the regulatory networks of differentially expressed genes. Twelve matched pairs of AD and control brain microvessel samples are hybridized to Agilent Human 4 × 44 K arrays in replication. We document that more than 2,000 genes are differentially altered in AD microvessels and that a large number of these genes map to pathways associated with immune and inflammatory response, signal transduction, and nervous system development and function categories. These data may help elucidate heretofore unknown molecular alterations in the AD cerebromicrovasculature. Two condition experiment, diseased vs normal, our study included 12 pairs of biological replicates and each pair was repeated with dye swap making total of 24 double channel hybridizations. we excluded 4 samples for not passing QC. So 20 samples were included in the data analysis.
2013-03-29 | E-GEOD-45596 | biostudies-arrayexpress
Project description:We recently surveyed the relationship between the human brain transcriptome and genome in a series of neuropathologically normal postmortem samples. We have now analyzed additional samples with a confirmed pathologic diagnosis of late-onset Alzheimer disease (LOAD; final n = 188 controls, 176 cases). Nine percent of the cortical transcripts that we analyzed had expression profiles correlated with their genotypes in the combined cohort, and approximately 5% of transcripts had SNP-transcript relationships that could distinguish LOAD samples. Two of these transcripts have been previously implicated in LOAD candidate-gene SNP-expression screens. This study shows how the relationship between common inherited genetic variants and brain transcript expression can be used in the study of human brain disorders. We suggest that studying the transcriptome as a quantitative endo-phenotype has greater power for discovering risk SNPs influencing expression than the use of discrete diagnostic categories such as presence or absence of disease.
| S-EPMC2667989 | biostudies-literature
Project description:The enigma that is Alzheimer's disease (AD) continues to present daunting challenges for effective therapeutic intervention. The lack of disease-modifying therapies may, in part, be attributable to the narrow research focus employed to understand this complex disease. Most studies into disease pathogenesis are based on a priori assumptions about the role of AD lesion-associated proteins such as amyloid-β and tau. However, the complex disease processes at work may not be amenable to single-target therapeutic approaches. Genome-wide expression studies provide an unbiased approach for investigating the pathogenesis of complex diseases like AD. A growing literature suggests a role for cerebrovascular contributions to the pathogenesis of AD. The objective of the current study is to examine human brain microvessels isolated from AD patients and controls by microarray analysis. Differentially expressed genes with more than 2-fold change are used for further data analysis. Gene ontology analysis and pathway analysis algorithms within GeneSpringGX are employed to understand the regulatory networks of differentially expressed genes. Twelve matched pairs of AD and control brain microvessel samples are hybridized to Agilent Human 4 × 44 K arrays in replication. We document that more than 2,000 genes are differentially altered in AD microvessels and that a large number of these genes map to pathways associated with immune and inflammatory response, signal transduction, and nervous system development and function categories. These data may help elucidate heretofore unknown molecular alterations in the AD cerebromicrovasculature.
2013-03-29 | GSE45596 | GEO
Project description:ObjectiveTo determine whether age-standardized brain morphometric and cognitive profiles differ in young-old (aged 60-75 years) and very-old (aged 80-91 years) patients with Alzheimer disease (AD).MethodsUsing a case-control retrospective design, we compared hippocampal volume and cortical gray matter thickness in areas known to be affected by AD in 105 patients with AD and 125 healthy control (HC) participants divided into young-old and very-old subgroups. Brain morphometric and cognitive scores of the AD groups were standardized to their respective age-appropriate HC subgroup and then compared.ResultsSeveral cognitive domains (executive function, immediate memory, and attention/processing speed) were less abnormal in the very old with AD than in the young old with AD. Similarly, the very old with AD showed less severe cortical thinning than the young old with AD in the left posterior cingulate cortex, right lateral temporal cortex, and bilateral parietal cortex and in overall cortical thickness. This effect is partially explained by an age-related decrease in cortical thickness in these brain regions in the HC participants.ConclusionsThe typical pattern of AD-related cognitive and morphometric changes seen in the young old appear to be less salient in the very old. Thus, mild cases of AD in the very old may go undetected if one expects to see the prototypical pattern and severity of cognitive or brain changes that occur in the young old with AD. These results underscore the importance of interpreting neuropsychological test performance and morphometric brain measures in reference to the individual's age.
| S-EPMC3164395 | biostudies-literature
Project description:Lack of clear understanding remains on the overlapping atrophy patterns of aging and early Alzheimer disease (AD) pathology in gray matter (GM) of the brain in vivo.To evaluate the independent and overlapping patterns of GM atrophy in normal aging and AD.A total of 169 cognitively normal subjects and 33 persons with probable AD enrolled in the longitudinal Cardiovascular Health Study-Cognition Study underwent 3-dimensional volumetric MRI scans. Controls remained cognitively normal for at least 5 years after their MRI scans and the probable AD subjects were relatively early in their clinical course with an average modified Mini-Mental State Examination score of 76/100. The scans were analyzed using voxel-based morphometry adjusting for total intracranial volume, gender, education, and race.With older age, GM volume was lower in the sensorimotor and heteromodal association areas in frontal, temporal, occipital, and parietal lobes, as well as in the cerebellum (false discovery rate p = 0.05). Additional atrophy was observed in the posterior hippocampus, thalamus, and middle cingulate gyrus. By contrast, atrophy was seen in subjects with AD in the anterior hippocampal/parahippocampal regions and the precuneus. Normal aging and AD overlapped in the hippocampal body and the entorhinal cortex.Brain atrophy with aging was observed in supratentorial and infratentorial areas, as well in primary motor, sensory, and heteromodal association regions. Age and Alzheimer disease exert independent gray matter atrophy patterns but these effects overlapped substantially in the hippocampus and entorhinal cortex.
| S-EPMC2788799 | biostudies-literature