Project description:It is unknown if adult human skeletal muscle has an epigenetic memory of earlier encounters with growth. We report, for the first time in humans, genome-wide DNA methylation (850,000CpGs) and gene expression analysis after muscle hypertrophy (loading), return of muscle mass to baseline (unloading), followed by later hypertrophy (reloading). We discovered increased frequency of hypomethylation across the genome after reloading (18,816 CpGs) versus earlier loading (9,153 CpG sites). We also identified AXIN1, GRIK2, CAMK4, TRAF1 as hypomethylated genes with enhanced expression after loading that maintained their hypomethylated status even during unloading where muscle mass returned to control levels, indicating a memory of these genes methylation signatures following earlier hypertrophy. Further, UBR5, RPL35a, HEG1, PLA2G16, SETD3 displayed hypomethylation and enhanced gene expression following loading, and demonstrated the largest increases in hypomethylation, gene expression and muscle mass after later reloading, indicating an epigenetic memory in these genes. Finally, genes; GRIK2, TRAF1, BICC1, STAG1 were epigenetically sensitive genes demonstrating hypomethylation after a single bout of resistance exercise that was maintained 22 weeks later with the largest increase in gene expression and muscle mass after reloading. Overall, we identify an important epigenetic role for a number of largely unstudied genes in muscle hypertrophy/ memory.
Project description:A genome-wide CRISPR screen was combined with a tdTomato reporter-based epigenetic memory assay to identify factors that erase epigenetic memory in ESC. After introducing genome wide perturbation and dCas9::KRAB-mediated epigenetic editing of the Esg1-tdTomato reporter, the trigger was released and cells that maintained the silencing sorted at FACS. Samples were collected out of sorted tdTomato negative (TOMminus) and positive (TOMplus) cells after 6 days of DOX treatment (epigenetic editing) and 3 or 7 days of DOX washout (release of the trigger), using a gating strategy to separate the bottom 2.5% negative cells (2.5%gate) and cells ranging from mildly to fully repressed (widegate).
Project description:Memory T cells are primed for rapid responses to antigen; however, the molecular mechanisms responsible for priming remain incompletely defined. CpG methylation in promoters is an epigenetic modification, which regulates gene transcription. Using targeted bisulfite sequencing, we examined methylation of 2100 genes (56,000 CpG) mapped by deep sequencing to T cell activation in human naïve and memory CD4 T cells. 466 CpGs (132 genes) displayed differential methylation between naïve and memory cells. 21 genes exhibited both differential methylation and gene expression before activation, linking promoter DNA methylation states to gene regulation; 6 genes encode proteins closely studied in T cells while 15 genes represent novel targets for further study. 39 genes exhibited reduced methylation in memory cells coupled with increased gene expression with activation compared to naïve cells, revealing specific genes more rapidly expressed in memory compared to naïve cells and potentially regulated by DNA methylation. These findings define a DNA methylation signature unique to memory CD4 T cells and correlated with activation-induced gene expression. Targeted bisulfite sequencing of primary human naïve and memory CD4 T cells at rest and 48 hours post-activation.
Project description:Memory CD8+ T cells have the ability to provide lifelong immunity against pathogens. Although memory features generally arise after challenge with a foreign antigen, naïve CD8 single positive (SP) thymocytes may acquire phenotypic and functional characteristics of memory cells in response to cytokines such as interleukin-4. This process is associated with the induction of the T-box transcription factor Eomesodermin (EOMES). However, the underlying molecular mechanisms remain ill-defined. Using epigenomic profiling, we show that these innate memory CD8SP cells acquire only a portion of the active enhancer repertoire of conventional memory cells. This reprograming is secondary to EOMES recruitment, mostly to RUNX3-bound enhancers. Furthermore, EOMES is found within chromatin-associated complexes containing BRG1 and promotes the recruitment of this chromatin remodelling factor. Also, the in vivo acquisition of EOMES-dependent program is BRG1-dependent. In conclusion, our results support a strong epigenetic basis for the EOMES-driven establishment of CD8+ T cell innate memory program.
Project description:DNA methylation patterns are set up in a relatively fixed programmed manner during normal embryonic development and are then stably maintained. Using genome-wide analysis, we have discovered a postnatal pathway involving gender-specific demethylation that occurs exclusively in the male liver. This demodification is programmed to take place at tissue-specific enhancer sequences, and our data show that the methylation state at these loci is associated with and appears to play a role in the transcriptional regulation of nearby genes. This process is mediated by the secretion of testosterone at the time of sexual maturity, but the resulting methylation profile is stable and therefore can serve as an epigenetic memory even in the absence of this inducer. These findings add a new dimension to our understanding of the role of DNA methylation in vivo and provide the foundations for deciphering how environment can impact on the epigenetic regulation of genes, in general. DNA methylation profile of male and female mouse and Human tissues was generated using the RRBS protocol followed by deep sequncing. Whole genome DNA methylation profile using deep sequencing was genereted for male and female mouse tissues. RNAseq was performed on male and female mouse tissues.
Project description:Memory T cells are primed for rapid responses to antigen; however, the molecular mechanisms responsible for priming remain incompletely defined. CpG methylation in promoters is an epigenetic modification, which regulates gene transcription. Using targeted bisulfite sequencing, we examined methylation of 2100 genes (56,000 CpG) mapped by deep sequencing to T cell activation in human naïve and memory CD4 T cells. 466 CpGs (132 genes) displayed differential methylation between naïve and memory cells. 21 genes exhibited both differential methylation and gene expression before activation, linking promoter DNA methylation states to gene regulation; 6 genes encode proteins closely studied in T cells while 15 genes represent novel targets for further study. 39 genes exhibited reduced methylation in memory cells coupled with increased gene expression with activation compared to naïve cells, revealing specific genes more rapidly expressed in memory compared to naïve cells and potentially regulated by DNA methylation. These findings define a DNA methylation signature unique to memory CD4 T cells and correlated with activation-induced gene expression. transcriptome of primary human naïve and memory CD4 T cells at rest and 48 hours post-activation.