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:Sexual dimorphism in mammals is mostly attributable to sex-related hormonal differences in fetal and adult tissues; however, this may not be the sole determinant. Though genetically-identical for autosomal chromosomes, male and female preimplantation embryos could display sex-specific transcriptional regulation which can only be attributted to the differences in sexual chromosome dosage. We used microarrays to analyze sex-related transcriptional differences at the blastocyst stage.
Project description:Individualized outcome prediction classifiers were successfully constructed through expression profiling of a total of 779 genes in microglial cells from 36 mice, which had been consecutively operated on within a defined short period of time
Project description:Background: Women represent the majority of Alzheimer’s disease patients and show typical symptoms. Genetic, hormonal and behavioral mechanisms have been proposed to explain gender differences in dementia prevalence. Whether sex differences exist in the epigenetic landscape of neuronal tissue during the progression of the disease is unknown. Methods: To investigate the differences of histone H3 modifications important for transcription we determined the ge-nome-wide profiles in K4me3, K27ac and K27me3 from brain cortexes of an Alzheimer mouse model (PSAPP). Gastrocnemius muscles were also tested since they are known to be different in the two sexes and are affected during the disease progression. Results: Correlation analysis dis-tinguished the samples based on sex for H3K4me3 and H3K27met3 but not for H3K27ac. The analysis of TSS signal distribution and of bounding sites revealed that the epigenetic landscape of gastrocnemius is more influenced than brain by sex, with the exception of H3K27me3 distribution on the X chromosome which showed sex-related differences in promoters belonging to behavior and cellular/ neuronal spheres in mice cortexes. Conclusions: The epigenetic landscape is slightly affected by sex in brain, with the exception of H3K27me3. On the other hand, a higher number of differences can be found in gastrocnemius.
Project description:Mouse models of Alzheimer’s Disease (AD), which show progression through various AD stages reflective of human pathology, like 5XFAD, are well established tools for uncovering novel AD related pathways. In addition, they permit temporal examination of the intermingling of AD related pathways and can be used to potentially dissect initiating and propagating events in AD, which are critical for developing biomarkers or designing interventions in early stages of the disease. The present research offers a robust and exhaustive tandem MS examination of a familial AD mice model with a design including variables of: time (three, six, and nine months), genetic background (5XFAD vs. WT), and sex (equal males and females).
Project description:Sexual dimorphism in mammals is mostly attributable to sex-related hormonal differences in fetal and adult tissues; however, this may not be the sole determinant. Though genetically-identical for autosomal chromosomes, male and female preimplantation embryos could display sex-specific transcriptional regulation which can only be attributted to the differences in sexual chromosome dosage. We used microarrays to analyze sex-related transcriptional differences at the blastocyst stage. Day 7 bovine in vitro produced bovine blastocysts produced with sorted semen from 3 different bulls. Pooled RNA from 60 blastocysts of one sex and produced with one bull was used per chip. Three replicates of each sex per bull. In total, 18 Bovine GeneChip (Affymetrix) were used (3 replicates X 3 bulls X 2 sexes).
Project description:Sex differences in the brain as they relate to health and disease are often overlooked in experimental models. Many neurological disorders, like Alzheimer’s disease (AD), multiple sclerosis (MS), and autism, differ in prevalence between males and females. Sex differences originate either from differential gene expression on sex chromosomes or from hormonal differences, either directly or indirectly. To disentangle the relative contributions of genetic sex (XX v. XY) and gonadal sex (ovaries v. testes) to the regulation of hippocampal sex effects, we use the “sex-reversal” Four Core Genotype (FCG) mouse model which uncouples sex chromosome complement from gonadal sex. Transcriptomic and epigenomic analyses of hippocampal RNA and DNA from ∼12 month old FCG mice, reveals differential regulatory effects of sex chromosome content and gonadal sex on X- versus autosome-encoded gene expression and DNA modification patterns. Gene expression and DNA methylation patterns on the X chromosome were driven primarily by sex chromosome content, not gonadal sex. The majority of DNA methylation changes involved hypermethylation in the XX genotypes (as compared to XY) in the CpG context, with the largest differences in CpG islands, promoters, and CTCF binding sites. Autosomal gene expression and DNA modifications demonstrated regulation by sex chromosome complement and gonadal sex. These data demonstrate the importance of sex chromosomes themselves, independent of hormonal status, in regulating hippocampal sex effects. Future studies will need to further interrogate specific CNS cell types, identify the mechanisms by which sex chromosome regulate autosomes, and differentiate organizational from activational hormonal effects.
Project description:Sex differences in the brain as they relate to health and disease are often overlooked in experimental models. Many neurological disorders, like Alzheimer’s disease (AD), multiple sclerosis (MS), and autism, differ in prevalence between males and females. Sex differences originate either from differential gene expression on sex chromosomes or from hormonal differences, either directly or indirectly. To disentangle the relative contributions of genetic sex (XX v. XY) and gonadal sex (ovaries v. testes) to the regulation of hippocampal sex effects, we use the “sex-reversal” Four Core Genotype (FCG) mouse model which uncouples sex chromosome complement from gonadal sex. Transcriptomic and epigenomic analyses of hippocampal RNA and DNA from ∼12 month old FCG mice, reveals differential regulatory effects of sex chromosome content and gonadal sex on X- versus autosome-encoded gene expression and DNA modification patterns. Gene expression and DNA methylation patterns on the X chromosome were driven primarily by sex chromosome content, not gonadal sex. The majority of DNA methylation changes involved hypermethylation in the XX genotypes (as compared to XY) in the CpG context, with the largest differences in CpG islands, promoters, and CTCF binding sites. Autosomal gene expression and DNA modifications demonstrated regulation by sex chromosome complement and gonadal sex. These data demonstrate the importance of sex chromosomes themselves, independent of hormonal status, in regulating hippocampal sex effects. Future studies will need to further interrogate specific CNS cell types, identify the mechanisms by which sex chromosome regulate autosomes, and differentiate organizational from activational hormonal effects.
Project description:Recently genome-wide association studies have identified significant association between Alzheimer’s disease and variations in CLU, PICALM, BIN1, CR1, MS4A4/MS4A6E, CD2AP, CD33, EPHA1 and ABCA7. However, the pathogenic variants in these loci have not yet been found. We conducted a genome-wide scan for large copy number variations (CNVs) in a dataset of Caribbean Hispanic origin (554 controls and 559 cases with late-onset Alzheimer’s disease) that was previously investigated in a SNP-based genome-wide association study using Illumina HumanHap 650Y platform. We ran four CNV calling algorithms and analyzed rare large CNVs (>100 Kb) to obtain high-confidence calls that were detected by at least two algorithms. In total, 734 such CNVs were observed in our dataset. Global burden analyses did not reveal significant differences between cases and controls in CNV rate, distribution of deletions or duplications, total or average CNV size; and number of genes affected by CNVs. However, we observed a nominal association between Alzheimer’s disease and a ~470 Kb duplication on chromosome15q11.2 (P=0.037). This duplication, encompassing up to five genes (TUBGCP5, CYFIP1, NIPA2, NIPA1 and WHAMML1) was present in 10 cases (2.6%) and 3 controls (0.8%). The dosage increase of CYFIP1 and NIPA1 genes was further confirmed by quantitative PCR. The current study did not detect CNVs (including common CNVs) that affect novel Alzheimer’s disease loci reported by large genome-wide association studies. However, since the array technology used in our study has limitations in detecting small CNVs, future studies must carefully assess novel AD associated genes for the presence of disease related CNVs. Case-control analysis, screening of large copy number variation in 559 Alzheimer cases and 554 control subjects of Caribbean Hispanic ancestry
Project description:Alzheimer’s disease (AD), the most common age-related neurodegenerative disease, is closely associated with and manifested by neuroinflammation, yet the alteration of immune landscape in AD is largely unknown, preventing a deeper mechanistic understanding of neuroinflammation in AD. Two thirds of AD patients are females, and women have a higher risk of developing AD. Women with AD have more extensive brain histological changes than men with AD, more severe cognitive symptoms, and more severe neurodegeneration, suggesting that the disease affects female and male brains differentially. Despite evident AD sex variance, mechanisms and pathways are still poorly understood. Thus, a focus on sex differences in AD is essential to move the field towards effective interventions and to develop sex-specific therapies. To understand the cellular heterogeneity and disease-associated cellular changes in human AD brain, we performed unbiased massively parallel single nucleus RNA sequencing with postmortem frozen human brain tissues of middle temporal gyrus, a brain cortical region strongly affected by AD. From 12 individuals with and without AD, we isolated brain nuclei by sucrose gradient ultracentrifugation, generated single nucleus libraries with 10x Chromium platform (10x Genomics), and sequenced on NovaSeq6000 S4 sequencer (Illumina). We integrated snRNA-seq data of human brains from these 12 individuals of both Alzheimer’s Disease (AD, Braak Stage V/VI, n = 6) and age-matched healthy controls (HC, Braak Stage I/II, n = 6) by single nucleus analysis using Seurat. After quality control filtering, we profiled and analyzed 64,845 single nucleus transcriptomes, clustered all the cells jointly across the 12 donors that include 6 females and 6 males, and identified and annotated the major cell types of the human brain by interrogating the expression patterns of known gene markers, including neurons, excitatory neurons, inhibitory neurons, astrocytes, microglia, oligodendrocytes, oligodendrocyte precursor cells, endothelial cells, and pericytes.