Project description:Human ageing affects the immune system resulting in an overall decline in immunocompetence. Although all immune cells are affected during aging, the functional capacity of T cells is most influenced and is linked to decreased responsiveness to infections and impaired differentiation. We studied age-related changes in DNA methylation and gene expression in CD4+ and CD8+ T cells from younger and older individuals. We observed marked difference between T cell subsets, with increased number of methylation changes and higher methylome variation in CD8+ T cells with age. The majority of age-related hypermethylated sites were located at CpG islands of silent genes and enriched for repressive histone marks. Specifically, in CD8+ T cell subset we identified strong inverse correlation between methylation and expression levels in genes associated with T cell mediated immune response (LGALS1, IFNG, CCL5, GZMH, CCR7, CD27 and CD248) and differentiation (SATB1, TCF7, BCL11B and RUNX3). Our results thus suggest the link between age-related epigenetic changes and impaired T cell function.
Project description:The impact of healthy aging on molecular programming of immune cells is poorly understood. Here, we report comprehensive characterization of healthy aging in human classical monocytes, with a focus on epigenomic, transcriptomic, and proteomic alterations, as well as the corresponding proteomic and metabolomic data for plasma, using healthy cohorts of 20 young and 20 older males (~27 and ~64 years old on average). For each individual, we performed eRRBS-based DNA methylation profiling, which allowed us to identify a set of age-associated differentially methylated regions (DMRs) – a novel, cell-type specific signature of aging in DNA methylome. Hypermethylation events were associated with H3K27me3 in the CpG islands near promoters of lowly-expressed genes, while hypomethylated DMRs were enriched in H3K4me1 marked regions and associated with age-related increase of expression of the corresponding genes, providing a link between DNA methylation and age-associated transcriptional changes in primary human cells.
2022-02-16 | PXD021821 | Pride
Project description:Age-related methylation changes are associated with altered transcriptional circuitry
Project description:Aging of immune system is characterized by progressive decline of physiological and cellular function of T cells. Recent studies of naïve T cells from young and old mice have identified age-related altered gene expressions but the mechanisms underlying age associated changes of naïve T cells remain poorly understood. Here we compared the transcriptome and chromatin accessibility in mature CD4 and CD8 thymocytes and in naïve CD4 and CD8 T cells of spleen between young (6-8 weeks) and old (79-121 weeks) C57Bl/6 mice. We used Agilent microarray method and identified the age-related altering gene expressions 1) only in mature CD4 and CD8 T cell from thymus, 2) shared by both thymus and spleen naïve T cells, and 3) only in naïve T cells from spleen. The shared changes include increased chemokine and chemokine receptor expressions and decreased cell cycle regulator expression. We further analyzed the chromatin basis of altered gene expression using Assaying Transposase Accessible Chromatin with high-throughput sequencing (ATAC-seq) between young and old mice. We have identified age-related changes of chromatin accessibility in T cells from thymus and spleen, and some correlated changes between gene expression and chromatin accessibility. Overall, we observedmore age-related alterations of gene expression and chromatin accessibility inthymus than in spleen, suggesting some age-related changes of T cells in thymus did not retain in periphery. Together, our findings have identified tissue specific altered gene expressions and chromatin status in T cells during aging and further study of these altered genes will shed new insights into the mechanisms underlying these age-related changes.
Project description:Aging of immune system is characterized by progressive decline of physiological and cellular function of T cells. Recent studies of naïve T cells from young and old mice have identified age-related altered gene expressions but the mechanisms underlying age associated changes of naïve T cells remain poorly understood. Here we compared the transcriptome and chromatin accessibility in mature CD4 and CD8 thymocytes and in naïve CD4 and CD8 T cells of spleen between young (6-8 weeks) and old (79-121 weeks) C57Bl/6 mice. We used Agilent microarray method and identified the age-related altering gene expressions 1) only in mature CD4 and CD8 T cell from thymus, 2) shared by both thymus and spleen naïve T cells, and 3) only in naïve T cells from spleen. The shared changes include increased chemokine and chemokine receptor expressions and decreased cell cycle regulator expression. We further analyzed the chromatin basis of altered gene expression using Assaying Transposase Accessible Chromatin with high-throughput sequencing (ATAC-seq) between young and old mice. We have identified age-related changes of chromatin accessibility in T cells from thymus and spleen, and some correlated changes between gene expression and chromatin accessibility. Overall, we observedmore age-related alterations of gene expression and chromatin accessibility inthymus than in spleen, suggesting some age-related changes of T cells in thymus did not retain in periphery. Together, our findings have identified tissue specific altered gene expressions and chromatin status in T cells during aging and further study of these altered genes will shed new insights into the mechanisms underlying these age-related changes.
Project description:Changes in peripheral CD8+ T cells are a prominent hallmark of immune aging. While infiltrating CD8+ T cells are implicated in aging and neurodegenerative disease-related pathology in the brain, the role of aged non-infiltrating CD8+ T cells has yet to be fully defined. Here, we show that targeting activated aged peripheral CD8+ T cells rescues age-related cognitive decline. Using heterochronic parabiosis and single cell transcriptomics analysis we observed that aged peripheral CD8+ T cells maintain properties intrinsic to their age, being refractory to the effects of a young or aged systemic milieu. Systemic exposure of young mice to aged CD8+ T cells elicited synaptic-related aging transcriptional signatures in the hippocampus and impaired cognition. Inhibiting migration of aged peripheral CD8+ T cells to lymph nodes mitigated pro-aging effects on the young hippocampus. Conversely, targeting aged CD8+ T cells restored synaptic-related signatures in the aged hippocampus and ameliorated cognitive impairments. Mechanistically, we identified granzyme k (GZMK) as a secreted age-associated CD8+ T cell-derived factor that impairs cognitive function. Together, our data identify activated aged CD8+ T cells and their secreted factors as potential therapeutic targets to rescue cognition in old age.
Project description:Changes in peripheral CD8+ T cells are a prominent hallmark of immune aging. While infiltrating CD8+ T cells are implicated in aging and neurodegenerative disease-related pathology in the brain, the role of aged non-infiltrating CD8+ T cells has yet to be fully defined. Here, we show that targeting activated aged peripheral CD8+ T cells rescues age-related cognitive decline. Using heterochronic parabiosis and single cell transcriptomics analysis we observed that aged peripheral CD8+ T cells maintain properties intrinsic to their age, being refractory to the effects of a young or aged systemic milieu. Systemic exposure of young mice to aged CD8+ T cells elicited synaptic-related aging transcriptional signatures in the hippocampus and impaired cognition. Inhibiting migration of aged peripheral CD8+ T cells to lymph nodes mitigated pro-aging effects on the young hippocampus. Conversely, targeting aged CD8+ T cells restored synaptic-related signatures in the aged hippocampus and ameliorated cognitive impairments. Mechanistically, we identified granzyme k (GZMK) as a secreted age-associated CD8+ T cell-derived factor that impairs cognitive function. Together, our data identify activated aged CD8+ T cells and their secreted factors as potential therapeutic targets to rescue cognition in old age.