ABSTRACT: Expression data from Alzheimer's disease (AD) model mouse and AD model mouse overexpressing human mitochondrial transcriptional factor A (hTFAM)
Project description:Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by progressive deterioration of cognitive function. Evidence suggests a role for epigenetic regulation, in particular the cytosine modifications 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC,) in AD. 5hmC is highly enriched in the nervous system and displays neurodevelopment and age-related changes. To determine the role of 5hmC in AD, we performed genome-wide analyses of 5hmC in DNA from prefrontal cortex of post-mortem AD as well as RNA-Seq to correlate changes in methylation status with transcriptional changes. We also utilized the existing AD fly model to further test the functional significance of these epigenetically altered loci. We identified 325 genes containing differentially hydroxymethylated loci (DhMLs) in both the discovery and replication datasets, and these are enriched for pathways involved in neuron projection development and neurogenesis. Of the 325 genes identified, 140 also showed changes in gene expression by RNA-Seq. Proteins encoded by genes identified in the current analysis form direct protein-protein interactions with AD-associated genes, expanding the network of genes implicated in AD. Furthermore, we identified AD-associated single nucleotide polymorphisms (SNPs) located within or near DhMLs, suggesting that these SNPs may identify regions of epigenetic gene regulation that play a role in AD pathogenesis. Finally using the existing AD fly model we showed that some of these genes could modulate the toxicity associated with AD. Our data implicate neuron projection development and neurogenesis pathways as potential targets in AD. These results indicate that incorporating epigenomic and transcriptomic data with GWAS data can expand the known network of genes involved in disease pathogenesis. Combination of epigenome profiling and Drosophila model enables us to identify the epigenetic modifiers of Alzheimer's disease. University of Kentucky Alzheimer's Disease Research Center (3 control, 3 Alzheimer's) and Emory University Alzheimer's Disease Research Center (2 control, 2 Alzheimer's)
Project description:Glucose hypometabolism is one of the major characteristics of Alzheimer's disease (AD). The energy deficiency in AD brain has been at least partially attributed to accelerated mitochondrial dysfunction than normal aging. In earlier publications, we have shown that small molecule mitochondrial complex I inhibitor CP2 facilitated mitochondrial regeneration and rescued mitochondrial deficiency in familial AD mice model APP-PS1. Here in this study, we investigated whether a typical mitochondrial deficiency mouse model could recapitulate molecular expression signatures of AD brain and whether CP2 was able to rescue the AD brain phenotype. Ndufs4 is one of the regulatory subunits of mitochondria complex I. Knockout of Ndufs4 resulted in complex I assembly failure and approximately half mitochondrial function loss. Ndufs4-knockout mice are viable but are short in lifespan (up to about 90 days). This model has been previously used to study Leigh syndrome, a heritable mitochondrial deficiency disease. In this dataset, we performed RNAseq on brains of CP2 treated Ndufs4-knockout mice and examined the expression changes upon CP2 treatment.
Project description:Expression data from the neuron model of Alzheimer's disease (AD) with or without treatment of recombinant human mitochondrial transcriptional factor A (rhTFAM) protein
Project description:Predisposition to Alzheimer's disease (AD) may arise from lipid metabolism perturbation, however, the underlying mechanism remains elusive. Here, we identify ATAD3A, a mitochondrial AAA-ATPase, as a molecular switch that links cholesterol metabolism impairment to AD phenotypes. In neuronal models of AD, the 5XFAD mouse model and post-mortem AD brains, ATAD3A is oligomerized and accumulated at the mitochondria-associated ER membranes (MAMs), where it induces cholesterol accumulation. Suppressing ATAD3A oligomerization by heterozygous ATAD3A knockout normalizes brain cholesterol turnover and MAM integrity, suppresses APP processing and synaptic loss, and consequently reduces AD neuropathology and cognitive deficits in AD transgenic mice. These findings reveal a role for ATAD3A oligomerization in AD pathogenesis and suggest ATAD3A as a potential therapeutic target for AD.
Project description:Alzheimer’s disease (AD) is a severe1 age-related neurodegenerative disorder characterized by accumulation of beta-amyloid (Aβ) plaques and neurofibrillary tangles, synaptic and neuronal loss, and cognitive decline. Several genes have been implicated in AD, but chromatin state alterations during neurodegeneration remain uncharacterized. Here, we profile transcriptional and chromatin state dynamics across early and late pathology in the hippocampus of an inducible mouse model of AD-like neurodegeneration. We find a coordinated downregulation of synaptic plasticity genes and regulatory regions, and upregulation of immune response genes and regulatory regions, which are targeted by factors that belong to the ETS family of transcriptional regulators, including PU.1. Human regions orthologous to increasing-level enhancers show immune cell-specific enhancer signatures as well as immune cell expression quantitative trait loci (eQTL), while decreasing-level enhancer orthologs show fetal brain specific enhancer activity. Surprisingly, AD-associated genetic variants are specifically enriched in increasing-level enhancer orthologs implicating immune processes in AD predisposition. Indeed, increasing enhancers overlap known AD loci lacking protein-altering variants and implicate additional loci that do not reach genome-wide significance. Our results reveal new insights into the mechanisms of neurodegeneration and establish the mouse as a useful model for functional studies of AD regulatory regions. We profiled gene expression levels through RNA-Seq and histone mark levels through ChIP-Seq to compare control mice to the CK-p25 Alzheimer's disease model at 2 weeks and 6 weeks after induction of neurodegeneration.
Project description:The effect of C1q knockout on brain gene expression was examined in non-transgenic and TauP301S mice. Complement pathway has been shown to play an important role in neurodegenerative diseases, and in-house data show that C1QC KO protects against neurodegeneration in Alzheimer's disease (AD) model. TauP301S mice have neuroinflammation and neurodegeneration in the brain and is AD model. The most severe pathology of this disease model is in hippocampus.
Project description:Little is known about the global molecular changes leading to neurodegeneration and brain dysfunction in Alzheimer's disease (AD). To study the molecular cascades involved, we chose to study the transcriptomic profile of an early-onset AD model, the 5xFAD mice, at different time points (1 month, 4 months, 6 months and 9 months) of the disease. We are also interested in the effects of vitamin D supplementation in AD. Vitamin D receptor belongs to the family of nuclear receptors and vitamin D can act as a neurosteroid by regulating the expression of over a 1000 genes. We therefore decided to evaluate the effect of vitamin D supplementation in this AD mouse model at the transcriptomic level, after 5 months of supplementation (i.e. from 1 month to 6 months and from 4 months to 9 months).
Project description:TREM2 is a microglial-specific gene implicated in late-onset Alzheimer's Disease (AD). Recent studies have identified that Trem2-deficient mice exhibit transcriptional changes in microglial gene expression that minimize the upregulation of lipid metabolism and lysosomal genes in AD disease models. We find that chronic phagocytic challenge from demyelination generates similiarly attenuated expression of lysosomal and lipid metabolism genes in microglia isolated from Trem2 knockout mouse brain.