Project description:We profiled REST targets in WT mice, as well as the Alzheimer’s disease 3xTg mouse model, to gain insight into the regulation of physiological pathways by REST, as well as the altered REST cistrome in Alzheimer’s disease.
Project description:Aging and sex are major risk factors for developing late-onset Alzheimer’s disease. Compared to men, women are not only nearly twice as likely to develop Alzheimer’s, but they also experience worse neuropathological burden and cognitive decline despite living longer with the disease. It remains unclear how and when sex differences in biological aging emerge and contribute to Alzheimer’s disease pathogenesis. We hypothesized that these differences lead to distinct molecular Alzheimer’s disease signatures in males and females, which could be harnessed for therapeutic and biomarker development. We aged male and female, 3xTg-AD and B6129 control mice across their respective lifespans while longitudinally collecting brain samples. We conducted RNA sequencing analysis on bulk brain tissue and examined differentially expressed genes between 3xTg-AD and B6129 samples and across ages in each sex. 3xTg-AD males experienced an accelerated upregulation of immune-related gene expression in the brain relative to females, especially in genes involved in complement system activation, suggesting distinct inflammatory disease trajectories between the sexes. Our data demonstrate that chronic inflammation and complement activation are associated with increased mortality, revealing that age-related changes in immune response act as a primary driver of sex differences in Alzheimer’s disease trajectories.
Project description:Cellular senescence has been associated with neurodegenerative disease and clearance of senescent cells using genetic or pharmaceutical strategies (senolytics) has demonstrated beneficial effects in mouse models investigating individual disease etiologies of Alzheimer’s disease (AD). However, it has remained unclear if senescent cell clearance in a mouse model exhibiting both plaque and tau pathologies modifies the disease state (3xTg). Here, we show that treatment with senolytics (ABT263 (navitoclax) or a combination of dasatinib and quercetin (D+Q)) or transgenic removal of p16-expressing cells (via INK-ATTAC) reduced microgliosis and ameliorated both amyloid and tau pathology in 3xTg mice. Using RNA sequencing, we found evidence that synaptic dysfunction and neuroinflammation was attenuated with senescent cell removal. Unfortunately, these beneficial effects were not seen with short-term senolytic treatment in mice with more advanced disease. Overall, our results further corroborate the beneficial effects senescent cell clearance could have on AD and highlight the importance of early intervention for treatment of this debilitating disease.
Project description:Transcriptional profiling of the microdissected SVZ from 7-month-old mice Adult neurogenesis is suppressed in the SVZ of 3xTg mice, a model of Alzheimer's disease. To better understand the underlying mechanisms of this suppression, the goals of this experiment were to compare the transcriptional profiles of the SVZ neural stem cell niche in 3xTg-AD mice versus strain controls. We used early middle-aged mice (7-months-old) rather than old mice, in order to identify genetic changes that are not caused secondarily to other degenerative changes occurring in these mice. Two-condition experiment, 3xTg vs WT SVZ. Biological replicates: 4 for each.
Project description:The 3xTg-AD mouse is a widely used model in the study of Alzheimer’s Disease (AD). It has been extensively characterized both from the anatomical and behavioral point of view but poorly studied at the transcriptomic level. For the first time, this study characterizes the whole blood transcriptome of the 3xTg-AD mouse at three and six months of age and evaluates how gene expression is modulated by transcranial direct current stimulation (tDCS). RNA-seq analysis revealed 183 differentially expressed genes (DEGs) that were a direct signature of the genetic background of the mouse. The expression profile of age-related genes in the 3 months-old 3xTg-AD mice was more similar to that of 6 months rather than 3 months-control mice, suggesting a premature aging of the 3xTg-AD mice. Moreover, in the 6 months-old 3xTg-AD mice, we observed a high number of DEGs that could represent good peripheral biomarkers of AD progression. Finally, tDCS was associated with gene expression changes in the 3xTg-AD but not in the control mice. In conclusion, this study provides a better molecular characterization of the 3xTg-AD mouse and suggests that blood gene expression can be used to identify new biomarkers of AD progression and treatments effect.
Project description:Approximately 35 million people worldwide suffer from Alzheimer’s disease (AD). Existing therapeutics, while moderately effective, are currently unable to stem the widespread rise in AD prevalence. AD is associated with an increase in amyloid beta (A) oligomers and hyperphosphorylated tau, along with cognitive impairment and neurodegeneration. Several antidepressants have shown promise in improving cognition and alleviating oxidative stress in AD but have failed as long-term therapeutics. In this study, amitriptyline, an FDA-approved tricyclic antidepressant, was administered orally to aged and cognitively impaired transgenic AD mice (3xTgAD). After amitriptyline treatment, cognitive behavior testing demonstrated that there was a significant improvement in both long- and short-term memory retention. Amitriptyline treatment also caused a significant potentiation of non-toxic A monomer with a concomitant decrease in toxic oligomer A load, compared to vehicle-treated 3xTgAD controls. In addition, amitriptyline administration caused a significant increase in dentate gyrus neurogenesis as well as increases in expression of neurosynaptic marker proteins. Amitriptyline treatment resulted in increases in hippocampal brain-derived neurotrophic factor protein as well as increased tyrosine phosphorylation of its cognate receptor (TrkB). These results indicate that amitriptyline has significant beneficial actions in aged and damaged AD brains and that it shows promise as a tolerable novel therapeutic for the treatment of AD. Male 3xTgAD mice, 14 months of age, were maintained on a 12hr light dark cycle in pathogen free conditions. Animals received food and water ad libitum. The test group received 100ug/g body weight amitriptyline-hydrochloride per os in their drinking water (Sigma-Aldrich, St. Louis MO) for 4 months (n = 15), and the control group received water (n = 15). The Hippocampus and Cortex were removed from 3 replicates of each group and RNA purification was done using glass bead disruption followed by the RNEasy Mini Kit (Qiagen, Valencia, CA) according to the manufacturer's instructions. The RNA was examined for quantity and quality using an Agilent Bioanalyzer 2100 (Agilent Technologies, Palo Alto, CA). The samples were hybridized to Illumina's SentrixMouse Ref-8 v2. Expression BeadChips (Illumina, San Diego, CA).
Project description:Alzheimer’s disease (AD)-related degenerative decline is associated to the presence of amyloid beta (Aβ) plaque lesions and neuro fibrillary tangles (NFT). However, the precise molecular mechanisms linking Aβ deposition and neurological decline are still unclear. Here we combine genome-wide transcriptional profiling of the insular cortex of 3xTg-AD mice and control littermates from early through to late adulthood (2-14 months of age), with behavioural and biochemical profiling in the same animals to identify transcriptional determinants of functional decline specifically associated to build-up of Aβ deposits. Differential expression analysis revealed differentially expressed genes (DEGs) in the cortex long before observed onset of behavioural symptoms in this model. Using behavioural and biochemical data derived from the same mice and samples, we found that down but not up-regulated DEGs show a stronger average association with learning performance than random background genes in control not seen in AD mice. Conversely, these same genes were found to have a stronger association with Aβ deposition than background genes in AD but not in control mice, thereby identifying these genes as potential intermediaries between abnormal Aβ/NFT deposition and functional decline. Using a complementary approach, gene ontology analysis revealed a highly significant enrichment of learning and memory, associative, memory and cognitive functions only among down-regulated, but not up-regulated, DEGs. Our results demonstrate wider transcriptional changes triggered by the abnormal deposition of Aβ/NFT occurring well before behavioural decline and identify a distinct set of genes specifically associated to abnormal Aβ protein deposition and cognitive decline.
Project description:Transcriptional profiling of the microdissected SVZ from 7-month-old mice Adult neurogenesis is suppressed in the SVZ of 3xTg mice, a model of Alzheimer's disease. To better understand the underlying mechanisms of this suppression, the goals of this experiment were to compare the transcriptional profiles of the SVZ neural stem cell niche in 3xTg-AD mice versus strain controls. We used early middle-aged mice (7-months-old) rather than old mice, in order to identify genetic changes that are not caused secondarily to other degenerative changes occurring in these mice.
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.