Project description:Altered DNA methylation patterns represent an attractive mechanism for the phenotypic changes associated with human aging. Several studies have described age-related methylation changes to various extents, but their functional significance has remained largely unclear. We have now used an integrated methylome and transcriptome sequencing approach to characterize age-related methylation changes in the human epidermis and to analyze their impact on gene expression. Our results show limited and localized methylation differences between young and old methylomes at single-base resolution. Similarly, the comparison of transcriptomes from young and old samples revealed a highly defined set of differentially expressed genes with functional annotations in skin homeostasis. Further data analysis showed a robust correlation between age-related promoter hypermethylation and gene silencing, particularly at promoters that were pre-marked with stem cell-specific chromatin features. In addition, we also observed age-related methylation changes at transcription factor binding sites, with a significant enrichment of stem cell regulatory networks. Our results provide a high-resolution analysis of age-related methylation changes and suggest that they result in highly defined alterations in the transcriptional programme of the human epidermis. Interestingly, several of our findings can be interpreted to reflect epigenetic changes in aging stem cells, thus supporting a critical role of stem cells in human aging. Whole genome methylation analysis of H. sapiens. Two samples were analyzed, one sample containing DNA from young, one sample containing DNA from old human skin.
Project description:Altered DNA methylation patterns represent an attractive mechanism for the phenotypic changes associated with human aging. Several studies have described age-related methylation changes to various extents, but their functional significance has remained largely unclear. We have now used an integrated methylome and transcriptome sequencing approach to characterize age-related methylation changes in the human epidermis and to analyze their impact on gene expression. Our results show limited and localized methylation differences between young and old methylomes at single-base resolution. Similarly, the comparison of transcriptomes from young and old samples revealed a highly defined set of differentially expressed genes with functional annotations in skin homeostasis. Further data analysis showed a robust correlation between age-related promoter hypermethylation and gene silencing, particularly at promoters that were pre-marked with stem cell-specific chromatin features. In addition, we also observed age-related methylation changes at transcription factor binding sites, with a significant enrichment of stem cell regulatory networks. Our results provide a high-resolution analysis of age-related methylation changes and suggest that they result in highly defined alterations in the transcriptional programme of the human epidermis. Interestingly, several of our findings can be interpreted to reflect epigenetic changes in aging stem cells, thus supporting a critical role of stem cells in human aging. Whole transcriptome analysis of H. sapiens. Two samples were analyzed, one sample containing RNA from young, one sample containing RNA from old human skin.
Project description:Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer type and arises from keratinocytes. Most cSCC progress from a UV-induced precancerous lesion termed actinic keratosis (AK). Despite various efforts to characterize these lesions molecularly, the etiology of AK and its progression to cSCC remain only partially understood. Here we have used Infinium MethylationEPIC BeadChips to interrogate the DNA methylation status of about 850.000 CpGs in epidermal preparations from healthy skin, AK and cSCC. Importantly, we found that the premalignant AK samples displayed classical features of cancer methylomes and were highly similar to cSCC methylomes. Further analysis identified typical features of stem cell methylomes, such as a reduced DNA methylation age, non-CpG methylation and stem cell-related keratin and enhancer methylation patterns. Interestingly, this signature was detected only in one half of the AK and cSCC samples, while the other half showed methylation patterns that were more closely related to the control epidermis. These findings suggest the existence of two distinct subclasses of AK and cSCC that originate from distinct keratinocyte differentiation stages.
Project description:Epigenetic changes represent an attractive mechanism for understanding the phenotypic changes associated with human aging. Age-related changes in DNA methylation at the genome scale have been termed epigenetic drift, but the defining features of this phenomenon remain to be established. Human epidermis represents an excellent model for understanding age-related epigenetic changes because of its substantial cell-type homogeneity and its well-known age-related phenotype. We have now generated and analyzed the currently largest set of human epidermis methylomes (N=108) using array-based profiling of 450,000 methylation marks in various age groups. Data analysis confirmed that age-related methylation differences are locally restricted and characterized by relatively small effect sizes. Nevertheless, methylation data could be used to predict the chronological age of sample donors with high accuracy. We also identified discontinuous methylation changes as a novel feature of the aging methylome. Finally, our analysis uncovers an age-related erosion of DNA methylation patterns that is characterized by a reduced dynamic range and increased heterogeneity of global methylation patterns. These changes in methylation variability were accompanied by a reduced connectivity of transcriptional networks. Our findings thus define the loss of epigenetic regulatory fidelity as a key feature of the aging epigenome. This data set contains data from methylation profiling by array of human epidermis samples. The results of transcription profiling by array are provided in the ArrayExpress experiment E-MTAB-4382.
Project description:Epigenetic changes represent an attractive mechanism for understanding the phenotypic changes associated with human aging. Age-related changes in DNA methylation at the genome scale have been termed epigenetic drift, but the defining features of this phenomenon remain to be established. Human epidermis represents an excellent model for understanding age-related epigenetic changes because of its substantial cell-type homogeneity and its well-known age-related phenotype. We have now generated and analyzed the currently largest set of human epidermis methylomes (N=108) using array-based profiling of 450,000 methylation marks in various age groups. Data analysis confirmed that age-related methylation differences are locally restricted and characterized by relatively small effect sizes. Nevertheless, methylation data could be used to predict the chronological age of sample donors with high accuracy. We also identified discontinuous methylation changes as a novel feature of the aging methylome. Finally, our analysis uncovers an age-related erosion of DNA methylation patterns that is characterized by a reduced dynamic range and increased heterogeneity of global methylation patterns. These changes in methylation variability were accompanied by a reduced connectivity of transcriptional networks. Our findings thus define the loss of epigenetic regulatory fidelity as a key feature of the aging epigenome. This data set contains data from transcription profiling by array of human epidermis samples. The results of methylation profiling are provided in the ArrayExpress experiment E-MTAB-4385.
Project description:Atopic Dermatitis (AD) is the most common inflammatory skin disease and characterized by a deficient epidermal barrier and cutaneous inflammation. Genetic studies suggest a key role of keratinocytes in AD pathogenesis, but the alterations in the proteome that occur in the entire epidermis have not been defined. Employing a pressure-cycling technology-data-independent acquisition (PCT-DIA) approach, we performed quantitative proteomics of epidermis from healthy volunteers and lesional and non-lesional skin of AD patients. Results were validated by targeted proteomics using parallel reaction monitoring mass spectrometry or by immunofluorescence staining. The identified proteins reflect the strong inflammation in lesional skin and the defect in keratinocyte differentiation and epidermal stratification. Most importantly, they reveal impaired activation of the NRF2-antioxidant pathway and reduced abundance of mitochondrial proteins involved in key metabolic pathways in the epidermis. These results provide insight into the molecular alterations in the epidermis of AD patients and identify novel targets for pharmaceutical intervention.
Project description:DNA methylation array data generated from epidermal samples (suction blister roofs) of healthy female subjects between 21 and 76 years. Aim of the project was the investigation of non-linearities in the human aging progression using an integrative multi-omics analysis. DNA was extracted from suction blisters taken from the volar forearms of each subject, bisulfite converted, and profiled using Illumina Infinium HumanMethylation450 BeadChip arrrays.
Project description:DNA methylation array data generated from epidermal samples (suction blister roofs) of healthy female subjects between 21 and 76 years. Aim of the project was the investigation of non-linearities in the human aging progression using an integrative multi-omics analysis. DNA was extracted from suction blisters taken from the volar forearms of each subject, bisulfite converted, and profiled using Illumina Infinium MethylationEPIC BeadChip arrrays.