Project description:Characterizing the detergent insoluble brain proteome of sporadic late-onset Alzheimer’s disease (LOAD) has identified proteins and pathways associated with disease pathogenesis. Similar studies in early onset Alzheimer’s disease cases due to presenilin-1 mutations (PS1-EOAD), along with more detailed correlations with insoluble proteomes from LOAD and AD transgenic rodents, are limited. We therefore utilized quantitative proteomics to identify proteins that were significantly changing in the PS1-EOAD insoluble proteome versus controls. Comparison with the LOAD insoluble proteome identified common pathologic AD markers in addition to unique PS1-EOAD insoluble proteins. Similarly, weighted correlation network analysis (WGCNA) identified PS1-EOAD and LOAD co-expression modules with both like and disparate expression levels. Finally, we compared the human PS1-EOAD insoluble proteome to transgenic AD mouse and rat insoluble proteomes to understand how well these models mimic the human disease. Although many common AD pathologic findings were found in the rodents, there were multiple PS1-EOAD proteome changes not well recapitulated in the animal models. These proteomic studies highlight unique PS1-EOAD proteome changes as compared to LOAD and identify limitations to using AD transgenic rodents to study some aspects of AD.
Project description:Alzheimer's disease (AD) is a chronic neurodegenerative disorder, accounting for up to 75 % of all dementia cases. Although the basis of AD etiology remains unknown, oxidative stress constitutes a major driver given its intimate association, specially at prodromic stages of the disease. In this line, Ubiquinol, the reduced form of coenzyme Q10, is a well-known neuroprotective antioxidant and has demonstrated significant effects in oxidative responses of β-Amyloid aggregation, internalization, and apoptosis-induced neurodegeneration. However, full extent of Ubiquinol effects in the context of AD is not yet known in detail. In this study, we designed a new methodology based on MALDI MSI for evaluating the peptide profile of the 3xTg-AD mice model fed a Ubiquinol-supplemented diet. By adopting functional analysis tools, we observed differential functional profile in hippocampus and cortex levels after 4- or 10-m o supplementation. Therefore, we also identified ACAD9, XPO1 and EIF3A as potential protein references for the diagnosis of AD at early/late stages.
Project description:The relationship between repetitive mild traumatic brain injury (r-mTBI) and Alzheimer’s disease (AD) is well-recognized. However, the precise nature of how r-mTBI leads to or precipitates AD pathogenesis is currently not understood. Part A: Plasma biomarkers potentially provide non-invasive tools for detecting neurological changes in the brain, and can reveal overlaps between long-term consequences of r-mTBI and AD. In this study we address this by generating time-dependent molecular profiles of response to r-mTBI and AD pathogenesis in mouse models using unbiased proteomic analyses. To model AD, we used the well-validated hTau and PSAPP(APP/PS1) mouse models that develop age-related tau and amyloid pathological features respectively, and our well-established model of r-mTBI in C57BL/6 mice. Plasma were collected at different ages (3, 9, and 15 months-old for hTau and PSAPP mice), encompassing pre-, peri- and post-“onset” of the cognitive and neuropathological phenotypes, or at different timepoints after r-mTBI (24hrs, 3, 6, 9 and 12 months post-injury). Liquid chromatography/mass spectrometry (LC-MS) approaches coupled with Tandem Mass Tag labeling technology were applied to develop molecular profiles of protein species that were significantly differentially expressed as a consequence of mTBI or AD. Mixed model ANOVA after Benjamini-Hochberg correction, and a stringent cut-off identified 31 proteins significantly changing in r-mTBI groups over time and, when compared with changes over time in sham mice, 13 of these were unique to the injured mice. The canonical pathways predicted to be modulated by these changes were LXR/RXR activation, production of nitric oxide and reactive oxygen species and complement systems. We identified 18 proteins significantly changing in PSAPP mice and 19 proteins in hTau mice compared to their wildtype littermates with ageing. Six proteins were found to be significantly regulated in all three models i.e. r-mTBI, hTau and PSAPP mice compared to their controls. The top canonical pathways coincidently changing in all three models were LXR/RXR activation, and production of nitric oxide and reactive oxygen species. This work suggests potential biomarkers for TBI and AD pathogenesis and for the overlap between these two, and warrant targeted investigation in human populations. Part B: In this part of the study we address the above problem by utilizing our unbiased proteomic approach to generate detailed time-dependent brain molecular profiles of response to repetitive mTBI and AD pathogenesis in established mouse models. The same animal models described above were used herein. A LC/MS approach coupled with TMT labeling was also employed. Results: Mixed model ANOVA after Benjamin Hochberg correction identified 30 and 47 proteins that were specifically unique and changing in the hippocampus and cortex, respectively, within the r-mTBI group alone when compared with changes overtime in sham mice. PI3K/AKT signaling, Protein Kinase A signaling and PPAR/RXR activation in the hippocampus, and Protein Kinase A signaling, GNRH signaling and B cell receptor signaling in the cortex were the top canonical systems significantly altered in injury groups compared to sham mice. Mixed model AONVA identified 19 proteins significantly changing in the cortex of PSAPP mice and 7 proteins in hTau mice compared to their relative wildtype littermates respectively. In addition to the heterogeneous changes observed in the TBI and AD mouse models, there was a notable convergence and coincidental change in 6 unique proteins identified in the repetitive mTBI model and the hTau and PSAPP model. These proteins ostensibly indicate significant common pathobiological responses involving alterations in mitochondrial bioenergetics and energy metabolism, aberrant cytoskeletal reorganization and alterations in intracellular signaling transduction cascades. Conclusion: We believe that this work could help identify the common molecular substrates responsible for the precipitation of AD pathogenesis following repetitive mTBI, and also help to identify novel biological targets for therapeutic modulation in mTBI and AD.
Project description:Alzheimer’s disease (AD) is the most common form of dementia and risk-influencing genetics implicates microglia and neuroimmunity in the pathogenesis of AD. iPSC-microglia are increasingly used as a model of AD but the relevance of common immune stimuli to model AD is unclear. We performed a detailed cross-comparison over time on the effects of combinatory stimulation of iPSC-microglia, and in particular their relevance to AD. We used single cell RNA-seq to measure the transcriptional response of iPSC-microglia after 24 and 48h of stimulation with PGE2 or LPS+IFN-γ either alone or in combination with ATPγS. We observed a shared core transcriptional response of iPSC-microglia to ATPγS and to LPS+IFN-γ, suggestive of a convergent mechanism of action. Across all conditions we observed a significant overlap and functional links to genes that change their expression levels in human microglia from AD patients. Using a data-led approach, we identify a common axis of transcriptomic change across AD genetic mouse model microglia and show that only LPS provokes a transcriptional response along this axis in mouse microglia and LPS+IFN-γ in human iSPC-microglia.
Project description:The hippocampus is a primary region affected in Alzheimer’s disease (AD). Because AD postmortem brain tissue is not available prior to symptomatic stage, we lack understanding of early cellular pathogenic mechanisms. To address this issue, we examined the cellular origin and progression of AD pathogenesis in patient-based model systems including iPSC-derived brain cells transplanted into the mouse brain hippocampus, as well as human post-mortem hippocampal tissues. Our data showcase patient-based models to study the cellular origin, progression, and prion-like spread of AD pathogenesis.
Project description:The relationship between repetitive mild traumatic brain injury (r-mTBI) and Alzheimer’s disease (AD) is well-recognized. However, the precise nature of how r-mTBI leads to or precipitates AD pathogenesis is currently not understood. Part A: Plasma biomarkers potentially provide non-invasive tools for detecting neurological changes in the brain, and can reveal overlaps between long-term consequences of r-mTBI and AD. In this study we address this by generating time-dependent molecular profiles of response to r-mTBI and AD pathogenesis in mouse models using unbiased proteomic analyses. To model AD, we used the well-validated hTau and PSAPP(APP/PS1) mouse models that develop age-related tau and amyloid pathological features respectively, and our well-established model of r-mTBI in C57BL/6 mice. Plasma were collected at different ages (3, 9, and 15 months-old for hTau and PSAPP mice), encompassing pre-, peri- and post-“onset” of the cognitive and neuropathological phenotypes, or at different timepoints after r-mTBI (24hrs, 3, 6, 9 and 12 months post-injury). Liquid chromatography/mass spectrometry (LC-MS) approaches coupled with Tandem Mass Tag labeling technology were applied to develop molecular profiles of protein species that were significantly differentially expressed as a consequence of mTBI or AD. Mixed model ANOVA after Benjamini-Hochberg correction, and a stringent cut-off identified 31 proteins significantly changing in r-mTBI groups over time and, when compared with changes over time in sham mice, 13 of these were unique to the injured mice. The canonical pathways predicted to be modulated by these changes were LXR/RXR activation, production of nitric oxide and reactive oxygen species and complement systems. We identified 18 proteins significantly changing in PSAPP mice and 19 proteins in hTau mice compared to their wildtype littermates with ageing. Six proteins were found to be significantly regulated in all three models i.e. r-mTBI, hTau and PSAPP mice compared to their controls. The top canonical pathways coincidently changing in all three models were LXR/RXR activation, and production of nitric oxide and reactive oxygen species. This work suggests potential biomarkers for TBI and AD pathogenesis and for the overlap between these two, and warrant targeted investigation in human populations. Part B: In this study we also address the aformention gap in the field by utilizing our unbiased proteomic approach to generate detailed time-dependent brain molecular profiles of response to repetitive mTBI and AD pathogenesis in established mouse models. Methods: We used the well-validated hTau and PSAPP(APP/PS1) mouse models that develops age-related tau and amyloid pathological features respectively, and our well-established model of repetitive-mTBI in C57BL/6 mice. Brain tissue from these animals were collected at different time points after repetitive mTBI (24hrs -12 months post-injury) and at different ages (3-15 months-old for hTau and PSAPP mice), encompassing pre-, peri- and post-“onset” of the cognitive and neuropathological phenotypes previously described in all models. Liquid chromatography/mass spectrometry (LC-MS) approach coupled with Tandem Mass Tag labeling technology were applied to reveal molecular profiles of proteins and pathways that are significantly altered as a consequence of AD or repetitive mTBI. Results: Mixed model ANOVA after Benjamin Hochberg correction identified 30 and 47 proteins that were specifically unique and changing in the hippocampus and cortex, respectively, within the r-mTBI group alone when compared with changes overtime in sham mice. PI3K/AKT signaling, Protein Kinase A signaling and PPAR/RXR activation in the hippocampus, and Protein Kinase A signaling, GNRH signaling and B cell receptor signaling in the cortex were the top canonical systems significantly altered in injury groups compared to sham mice. Mixed model AONVA identified 19 proteins significantly changing in the cortex of PSAPP mice and 7 proteins in hTau mice compared to their relative wildtype littermates respectively. In addition to the heterogeneous changes observed in the TBI and AD mouse models, there was a notable convergence and coincidental change in 6 unique proteins identified in the repetitive mTBI model and the hTau and PSAPP model. These proteins ostensibly indicate significant common pathobiological responses involving alterations in mitochondrial bioenergetics and energy metabolism, aberrant cytoskeletal reorganization and alterations in intracellular signaling transduction cascades. Conclusion: We believe that this work could help identify the common molecular substrates responsible for the precipitation of AD pathogenesis following repetitive mTBI, and also help to identify novel biological targets for therapeutic modulation in mTBI and AD.
Project description:The hippocampus is important for memory formation and is severely affected in the brain with Alzheimer's disease (AD). Since AD brain tissue is available postmortem, our understanding of early pathogenic processes occurring in hippocampi remains speculative. Here, an MS-based proteomic approach was used to analyze free-floating hippocampal spheroids (HSs) enriched in PROX1-positive granule neurons, from induced pluripotent stem cells (iPSCs) of healthy individuals and AD patients. HSs generated from two AD patients carrying variations in amyloid precursor protein (APP) or presenilin 1 (PS1) genes, and their age and gender matched controls.
Project description:We report the DNA methylation profiles in the brain cortex of animal models of neurodevelopmental disorders (rat with prenatal exposure to valproate and mouse with prenatal exposure to poly I:C) treated with TAK-418.