Project description:PSEN1 ΔE9 mutation causes a familial form of Alzheimer's disease. We have previously shown that human induced pluripotent stem cell (iPSC)-derived astrocytes carrying PSEN1 ΔE9 mutation exhibit transcriptional and functional abnormalities (Stem Cell Reports. 2017;9:1885-1897). Here we injected glial progenitors derived from 2 pairs of PSEN1 ΔE9 mutant- isogenic CTRL iPSCs intracerebroventricularly into newborn mice. At the age of 18 months, mouse hippocampi containing human cells (5 x PSEN1 ΔE9 + 6 x CTRL, all from male mice) were quickly dissected out and bulk RNA sequencing analysis was performed. Our results shed more light on the efffect of PSEN1 ΔE9 mutation on human glia in vivo as well as on the effect of the presence of mutant human glia on the surrounding healthy mouse cells.
Project description:The PSEN1 ΔE9 mutation causes a familial form of Alzheimer's disease (AD) by shifting the processing of amyloid precursor protein (APP) towards the generation of highly amyloidogenic Aβ42 peptide. We have previously shown that the PSEN1 ΔE9 mutation in human-induced pluripotent stem cell (iPSC)-derived astrocytes increases Aβ42 production and impairs cellular responses. Here, we injected PSEN1 ΔE9 mutant astrosphere-derived glial progenitors into newborn mice and investigated mouse behavior at the ages of 8, 12, and 16 months. While we did not find significant behavioral changes in younger mice, spatial learning and memory were paradoxically improved in 16-month-old PSEN1 ΔE9 glia-transplanted male mice as compared to age-matched isogenic control-transplanted animals. Memory improvement was associated with lower levels of soluble, but not insoluble, human Aβ42 in the mouse brain. We also found a decreased engraftment of PSEN1 ΔE9 mutant cells in the cingulate cortex and significant transcriptional changes in both human and mouse genes in the hippocampus, including the extracellular matrix-related genes. Overall, the presence of PSEN1 ΔE9 mutant glia exerted a more beneficial effect on aged mouse brain than the isogenic control human cells likely as a combination of several factors.
Project description:Drosophila ensheathing glia decline in relative numbers during normal aging. Using p35, we inhibit apoptosis specifically in ensheathing glia, and show that this is sufficient to rescue the decline in ensheathing glia, improve neuromotor performance of aged flies, and increase lifespan. Remaining ensheathing glia from aged brains exhibit transcriptomes exhibiting signs of lipid metabolism and apoptosis dysregulation. Expanding ensheathing glia with p35 also prevented the accumulation of amyloid plaques and delayed premature death in a fly model of Alzheimer's disease.
Project description:Alzheimer’s disease (AD) is the most common neurodegenerative dementia. Around 10% of cases present an age of onset before 65 years-old, which in turn can be divided in monogenic or familial AD (FAD) and sporadic early-onset AD (EOAD). Mutations in PSEN1, PSEN2 and APP genes have been linked with FAD. The aim of our study was to describe the brain whole-genome RNA expression profile of the posterior cingulate area in EOAD and FAD caused by PSEN1 mutations (FAD-PSEN1). 14 patients (7 EOAD and 7 FAD-PSEN1) and 7 neurologically healthy controls were selected and samples were hybridized in a Human Gene 1.1 microarray from Affymetrix. When comparing controls with EOAD and controls with FAD-PSEN1, we found 3183 and 3351 differentially expressed genes (DEG) respectively (FDR corrected p<0.05). However, any DEG was found in the comparison of the two groups of patients. Microarrays were validated through quantitative-PCR of 17 DEG. In silico analysis of the DEG revealed an alteration in biological pathways related to calcium-signaling, axon guidance and long-term potentiation (LTP), among others, in both groups of patients. These pathways are mainly related with cell signalling cascades, synaptic plasticity and learning and memory processes. In conclusion, the altered biological final pathways in EOAD and FAD-PSEN1 are highly coincident. Also, the findings are in line with those previously reported for late-onset AD (LOAD, onset >65 years-old), which implies that the consequences of the disease at the molecular level are similar in the final stages of the disease. 21 Samples were analyzed: 7 controls, 7 Early-onset Alzheimer's disease (AD) patients and 7 early-onset AD genetically determined by a mutation in PSEN1 gene.
Project description:Aging is often associated with cognitive decline, but many elderly individuals maintain a high level of function throughout life. Here we studied outbred rats, which also exhibit individual differences across a spectrum of outcomes that includes both preserved and impaired spatial memory. Previous work in this model identified the CA3 subfield of the hippocampus as a region critically affected by age and integral to differing cognitive outcomes. Earlier microarray profiling revealed distinct gene expression profiles in the CA3 region, under basal conditions, for aged rats with intact memory and those with impairment. Because prominent age-related deficits within the CA3 occur during neural encoding of new information, here we used microarray analysis to gain a broad perspective of the aged CA3 transcriptome under activated conditions. Behaviorally induced CA3 expression profiles differentiated aged rats with intact memory from those with impaired memory. In the activated profile, we observed substantial numbers of genes (greater than 1000) exhibiting increased expression in aged unimpaired rats relative to aged impaired, including many involved in synaptic plasticity and memory mechanisms. This unimpaired aged profile also overlapped significantly with a learning induced gene profile previously acquired in young adults. Alongside the increased transcripts common to both young learning and aged rats with preserved memory, many transcripts behaviorally-activated in the current study had previously been identified as repressed in the aged unimpaired phenotype in basal expression. A further distinct feature of the activated profile of aged rats with intact memory is the increased expression of an ensemble of genes involved in inhibitory synapse function, which could control the phenotype of neural hyperexcitability found in the CA3 region of aged impaired rats. These data support the conclusion that aged subjects with preserved memory recruit adaptive mechanisms to retain tight control over excitability under both basal and activated conditions. RNA profiles from cognitively unimpaired and impaired aged rats were compared under 2 conditions: spatial learning task and a non-spatial learning task.
Project description:The aim of this study was to investigate whether the differences in memory decline associated with aging are a result of differences in gene expression. We first categorized age-unimpaired and age-impaired rats based on their performance in the Morris Water Maze and then isolated messenger RNA from the CA1 hippocampal region of each animal to interrogate Affymetrix microarrays. Microarray analysis (p<0.005) identified a set of 50 genes that were transcribed differently in age-unimpaired animals that had successfully learned a spatial task compared to aged learning-impaired animals and a variety of groups designed to control for all non-learning aspects of exposure to the water maze paradigm. Experiment Overall Design: a total of 79 samples were analyzed including aged and young rats. One chip was interrogated per animal. Analysis of aged rat data includes 44 samples. Controls include cage controls, yoked controls (no platform), visible platform controls.
Project description:Alzheimer’s disease (AD) is the most common neurodegenerative dementia. Around 10% of cases present an age of onset before 65 years-old, which in turn can be divided in monogenic or familial AD (FAD) and sporadic early-onset AD (EOAD). Mutations in PSEN1, PSEN2 and APP genes have been linked with FAD. The aim of our study was to describe the brain whole-genome RNA expression profile of the posterior cingulate area in EOAD and FAD caused by PSEN1 mutations (FAD-PSEN1). 14 patients (7 EOAD and 7 FAD-PSEN1) and 7 neurologically healthy controls were selected and samples were hybridized in a Human Gene 1.1 microarray from Affymetrix. When comparing controls with EOAD and controls with FAD-PSEN1, we found 3183 and 3351 differentially expressed genes (DEG) respectively (FDR corrected p<0.05). However, any DEG was found in the comparison of the two groups of patients. Microarrays were validated through quantitative-PCR of 17 DEG. In silico analysis of the DEG revealed an alteration in biological pathways related to calcium-signaling, axon guidance and long-term potentiation (LTP), among others, in both groups of patients. These pathways are mainly related with cell signalling cascades, synaptic plasticity and learning and memory processes. In conclusion, the altered biological final pathways in EOAD and FAD-PSEN1 are highly coincident. Also, the findings are in line with those previously reported for late-onset AD (LOAD, onset >65 years-old), which implies that the consequences of the disease at the molecular level are similar in the final stages of the disease.
Project description:The aim of this study was to investigate whether the differences in memory decline associated with aging are a result of differences in gene expression. We first categorized age-unimpaired and age-impaired rats based on their performance in the Morris water maze, when compared to young rats. Then we isolated messenger RNA from the dentate gyrus of the hippocampus of each animal to interrogate Affymetrix RAE 230A rat genome microarrays. Supervised statistical analysis of the different groups of aged animals recognized 85 genes (p<0.005) that were significantly different in the dentate gyrus of aged rats that had learned the Morris water maze (MWM) paradigm when compared to learning impaired and a number of controls for stress, exercise and non-spatial learning. In addition, statistical analysis of the microarray data that included young and aged rats identified 1129 genes (p<0.005) that were differentially expressed between aged and young rats independent of behavior, but due to aging alone. Experiment Overall Design: a total of 80 samples were analyzed including aged and young rats for aged versus young comparisons. One chip was interrogated per animal. Supervised analysis of aged rat data (aged unimpaired (HID U) versus controls : HID I, VIS, YOKE, SIT includes 39 samples (intermediate learners were not included in the analysis). Controls include cage controls, yoke controls (no platform), visible platform controls.
Project description:The aim of this study was to investigate whether the differences in memory decline associated with aging are a result of differences in gene expression. We first categorized age-unimpaired and age-impaired rats based on their performance in the Morris water maze, when compared to young rats. Then we isolated messenger RNA from the dentate gyrus of the hippocampus of each animal to interrogate Affymetrix RAE 230A rat genome microarrays. Supervised statistical analysis of the different groups of aged animals recognized 85 genes (p<0.005) that were significantly different in the dentate gyrus of aged rats that had learned the Morris water maze (MWM) paradigm when compared to learning impaired and a number of controls for stress, exercise and non-spatial learning. In addition, statistical analysis of the microarray data that included young and aged rats identified 1129 genes (p<0.005) that were differentially expressed between aged and young rats independent of behavior, but due to aging alone. Keywords: behavior comparison, age comparison
Project description:Aging is often associated with cognitive decline, but many elderly individuals maintain a high level of function throughout life. Here we studied outbred rats, which also exhibit individual differences across a spectrum of outcomes that includes both preserved and impaired spatial memory. Previous work in this model identified the CA3 subfield of the hippocampus as a region critically affected by age and integral to differing cognitive outcomes. Earlier microarray profiling revealed distinct gene expression profiles in the CA3 region, under basal conditions, for aged rats with intact memory and those with impairment. Because prominent age-related deficits within the CA3 occur during neural encoding of new information, here we used microarray analysis to gain a broad perspective of the aged CA3 transcriptome under activated conditions. Behaviorally induced CA3 expression profiles differentiated aged rats with intact memory from those with impaired memory. In the activated profile, we observed substantial numbers of genes (greater than 1000) exhibiting increased expression in aged unimpaired rats relative to aged impaired, including many involved in synaptic plasticity and memory mechanisms. This unimpaired aged profile also overlapped significantly with a learning induced gene profile previously acquired in young adults. Alongside the increased transcripts common to both young learning and aged rats with preserved memory, many transcripts behaviorally-activated in the current study had previously been identified as repressed in the aged unimpaired phenotype in basal expression. A further distinct feature of the activated profile of aged rats with intact memory is the increased expression of an ensemble of genes involved in inhibitory synapse function, which could control the phenotype of neural hyperexcitability found in the CA3 region of aged impaired rats. These data support the conclusion that aged subjects with preserved memory recruit adaptive mechanisms to retain tight control over excitability under both basal and activated conditions.