Project description:CTE RNASeq association with APOE and TMEM. It is known that APOE is a risk factor of CTE. This study will look at differences between CTE stages - mild and severe, including associations with age, APOE and TMEM.
Project description:One of the hallmarks of Alzheimer’s disease is the presence of extracellular diffuse and fibrillar plaques predominantly consisting of the amyloid-β (Aβ) peptide. ApoE influences the deposition of amyloid pathology through affecting the clearance and aggregation of monomeric Aβ in the brain. In addition to influencing Aβ metabolism, increasing evidence suggests that apoE influences microglial function in neurodegenerative diseases. Here, we characterize the impact that apoE has on amyloid pathology and the innate immune response in APPPS1∆E9 and APPPS1-21 transgenic mice. We report that Apoe deficiency reduced fibrillar plaque deposition consistent with previous studies. However, fibrillar plaques in Apoe-deficient mice exhibited a striking reduction in plaque compaction. Hyperspectral fluorescent imaging using luminescent conjugated oligothiophenes identified distinct Aβ morphotypes in Apoe-deficient mice. We also observed a significant reduction in fibrillar plaque-associated microgliosis and activated microglial gene expression in Apoe-deficient mice, along with significant increases in dystrophic neurites around fibrillar plaques. Our results suggest that apoE is critical in stimulating the innate immune response to amyloid pathology.
Project description:SORL1 is implicated in the pathogenesis of Alzheimer’s disease (AD) through genetic studies. To interrogate the role(s) of SORL1 in human brain cells, SORL1 null iPSCs are differentiated to neuron, astrocyte, microglial, and endothelial cell fates. Loss of SORL1 leads to alterations in both overlapping and distinct pathways across cell types, with the greatest effects in neurons and astrocytes. SORL1 loss induces a neuron-specific reduction in APOE and CLU and altered lipid profiles. Enhancement of retromer-mediated trafficking rescues tau phenotypes observed in SORL1 null neurons but does not rescue APOE levels. Pathway analyses implicate TGF-β/SMAD signaling in SORL1 function, and modulating SMAD signaling in neurons alters APOE RNA levels in a SORL1-dependent manner. Analyses of iPSCs derived from a large cohort reveal a neuron-specific association between SORL1, APOE, and CLU levels, a finding validated in post-mortem brain. These studies provide a mechanistic link between strong genetic risk factors for AD.
Project description:The multi-ligand Receptor for AGE (RAGE) contributes to atherosclerosis in apolipoprotein (ApoE) null mice in both the non-diabetic and diabetic states. Previous studies using soluble RAGE, the extracellular ligand-binding domain of RAGE, or homozygous RAGE null mice showed that blockade or deletion of RAGE resulted in marked reduction in atherosclerotic lesion area and complexity compared to control animals. In parallel, significant down-regulation of inflammatory mediators and matrix metalloproteinases was evident in ApoE null mice aortas devoid of RAGE compared to those of ApoE null RAGE-expressing mice. Although these findings suggested that RAGE triggered pro-atherogenic mechanisms via regulation of inflammatory gene expression, these studies did not reveal the broader pathways by which RAGE contributed to atherosclerosis in ApoE null mice. Therefore, we performed Affymetrix gene expression arrays on aortas of non-diabetic and diabetic ApoE null mice expressing RAGE or devoid of RAGE at nine weeks of age, as this reflected a time point at which frank atherosclerotic lesions were not yet present, but, that we would be able to identify the genes likely involved in diabetes- and RAGE-dependent atherogenesis. The comparisons were as follows: 1. diabetic ApoE null relative to non-diabetic ApoE null; 2. non-diabetic ApoE null / RAGE null relative to non-diabetic ApoE null; 3. diabetic ApoE null / RAGE null relative to non-diabetic ApoE null / RAGE null; and 4. diabetic ApoE null / RAGE null relative to diabetic ApoE null aorta. Our data reveal that there is very little overlap of the genes which are differentially expressed both in the onset of diabetes in ApoE null mice, and in the effect of RAGE deletion in diabetic ApoE null mice. We next performed a Pathway-Express analysis to determine the pathways that were most associated with the onset of diabetes in ApoE null mice and the effect of RAGE gene deletion in diabetic ApoE null mice. Rigorous statistical analysis was undertaken and revealed that the transforming growth factor-beta pathway (tgf-beta) and focal adhesion pathways might be expected to play a significant role in both the mechanism by which diabetes facilitates the formation of atherosclerotic plaques in ApoE null mice, and the mechanism by which deletion of RAGE ameliorates this effect. We focused on three genes of the tgf-betafamily which were found to be up-regulated in diabetic vs. non-diabetic ApoE null aorta, and which were reduced by deletion of RAGE. These included: thrombospondin1 (Thbs1), transforming growth factor-beta (tgf-beta) and rho-associated kinase (ROCK1). Real-time quantitative polymerase chain reaction and Western blotting experiments were performed, as well as ROCK1 activity assays in mouse aorta, and validated the findings of the Affymetrix gene array. Further, confocal microscopy revealed that a principal cell type in the ApoE null aorta expressing these factors was the vascular smooth muscle cell. Our data suggest the novel finding that the observed reduction of accelerated atherosclerosis in diabetic ApoE null / RAGE null vs. diabetic ApoE null mice occurs, all or in part, through the ROCK1 branch of the TGF-betapathway. We have inferred a detailed mechanism for this process. Taken together, these data suggest that suppression of ROCK1 activity in the atherosclerosis-vulnerable vessel wall, especially in diabetes, but in non-diabetes as well, may underlie the beneficial effects of RAGE antagonism and genetic deletion in murine models. These findings highlight logical and novel targets for therapeutic intervention in cardiovascular disease and diabetes. 1. diabetic ApoE null relative to non-diabetic ApoE null; 2. non-diabetic ApoE null / RAGE null relative to non-diabetic ApoE null; 3. diabetic ApoE null / RAGE null relative to non-diabetic ApoE null / RAGE null; and 4. diabetic ApoE null / RAGE null relative to diabetic ApoE null aorta. There were 4 mice in each group initially. However there are only 3 non-diabetic ApoE null / RAGE null mice in the final experimental sample in group 3 due to a failure to generate cRNA from that sample. All samples were normalized to remove chip-dependent regularities using the RMA method. Chips and controls at each combination of genotype and disease sate were normalized together. The statistical significance of differential expression was calculated using the empirical Bayesian LIMMA (LInear Model for MicroArrays) method A cut-off B>0 was used for the statistical significance of gene expression.
Project description:Variations in many genes linked to sporadic Alzheimers disease (AD), show abundant expression in microglia, however, relationships between these genes remain largely elusive. Here, we establish isogenic human ES-derived microglia-like cell lines (hMGLs) harboring AD variants in CD33, INPP5D, SORL1 and TREM2 loci, and curate a comprehensive atlas comprising ATACseq, ChIPseq, RNAseq and proteomics datasets. AD-like expression signatures are observed in AD mutant SORL1 and TREM2 hMGLs, while integrative multi-omic analysis of combined epigenetic and expression datasets indicates upregulation of APOE as a convergent pathogenic node. We also observe cross-regulatory relationships between SORL1 and TREM2, where SORL1R744X hMGLs induce TREM2 expression to enhance APOE expression. AD-associated SORL1 and TREM2 mutations also impaired hMGL A-beta uptake in an APOE-dependent manner in vitro, and attenuated A-beta uptake/clearance in mouse AD brain xenotransplants. Utilizing this modeling and analysis platform for human microglia, we provide new insight into epistatic interactions in AD genes and demonstrate convergence of microglial AD genes at the APOE locus
Project description:Variations in many genes linked to sporadic Alzheimer’s disease (AD), show abundant expression in microglia, however, relationships between these genes remain largely elusive. Here, we establish isogenic human ES-derived microglia-like cell lines (hMGLs) harboring AD variants in CD33, INPP5D, SORL1 and TREM2 loci, and curate a comprehensive atlas comprising ATACseq, ChIPseq, RNAseq and proteomics datasets. AD-like expression signatures are observed in AD mutant SORL1 and TREM2 hMGLs, while integrative multi-omic analysis of combined epigenetic and expression datasets indicates upregulation of APOE as a convergent pathogenic node. We also observe cross-regulatory relationships between SORL1 and TREM2, where SORL1R744X hMGLs induce TREM2 expression to enhance APOE expression. AD-associated SORL1 and TREM2 mutations also impaired hMGL Aβ uptake in an APOE-dependent manner in vitro, and attenuated Aβ uptake/clearance in mouse AD brain xenotransplants. Utilizing this modeling and analysis platform for human microglia, we provide new insight into epistatic interactions in AD genes and demonstrate convergence of microglial AD genes at the APOE locus.
Project description:Variations in many genes linked to sporadic Alzheimer’s disease (AD), show abundant expression in microglia, however, relationships between these genes remain largely elusive. Here, we establish isogenic human ES-derived microglia-like cell lines (hMGLs) harboring AD variants in CD33, INPP5D, SORL1 and TREM2 loci, and curate a comprehensive atlas comprising ATACseq, ChIPseq, RNAseq and proteomics datasets. AD-like expression signatures are observed in AD mutant SORL1 and TREM2 hMGLs, while integrative multi-omic analysis of combined epigenetic and expression datasets indicates upregulation of APOE as a convergent pathogenic node. We also observe cross-regulatory relationships between SORL1 and TREM2, where SORL1R744X hMGLs induce TREM2 expression to enhance APOE expression. AD-associated SORL1 and TREM2 mutations also impaired hMGL Aβ uptake in an APOE-dependent manner in vitro, and attenuated Aβ uptake/clearance in mouse AD brain xenotransplants. Utilizing this modeling and analysis platform for human microglia, we provide new insight into epistatic interactions in AD genes and demonstrate convergence of microglial AD genes at the APOE locus.
Project description:APOE is the main genetic modifier for late onset Alzheimer’s disease (LOAD). While an APOE2/APOE3/APOE4 allelic series is well established for LOAD risk and neuropathology, molecular mechanisms underlying isoform-dependent risk and relevance of ApoE-associated lipids remain elusive. Here, we studied the effects of LPS stimulation on APOE KO iPSC-derived microglia treated with different ApoE isoforms (ApoE2/E3/E4) pre-complexed with BODIPY-cholesteryl ester (CE) and HDL -/+ recombinant LDLR extracellular domain.