Intra-sample heterogeneity of sperm DNA methylation
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ABSTRACT: Genome wide DNA methylation profiling of 2 distinct subpopulations of sperm within a single ejaculate. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs. Samples were provided by 20 normozoospermic individuals. A density gradient centrifugation was performed on each samples to yeild two distict populations for each ejaculate (one from the 90% isolate layer high quality sperm and one from the 35% isolate layer low quality sperm of the column).
Project description:Genome wide DNA methylation profiling of 2 distinct subpopulations of sperm within a single ejaculate. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs. Samples were provided by 20 normozoospermic individuals. A density gradient centrifugation was performed on each samples to yeild two distict populations for each ejaculate (one from the 90% isolate layer high quality sperm and one from the 35% isolate layer low quality sperm of the column). Bisulphite converted DNA from the 40 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip
Project description:Data about the entire sperm DNA methylome are limited to two sperm donors whereas studies dealing with a greater number of subjects focused only on a few genes or were based on low resolution arrays. This implies that information about what we can consider as a normal sperm DNA methylome and whether it is stable among different normozoospermic individuals is still missing. The definition of the DNA methylation profile of normozoospermic men, the entity of inter-individual variability and the epigenetic characterization of quality-fractioned sperm subpopulations in the same subject (intra-individual variability) are relevant for a better understanding of pathological conditions. We addressed these questions by using the high resolution Infinium 450K methylation array and compared normal sperm DNA methylomes against somatic cells. Our study, based on the largest number of subjects (n = 8) ever considered for such a large number of CpGs (n = 487,517), provided clear evidence for i) a highly conserved DNA methylation profile among normozoospermic subjects; ii) a stable sperm DNA methylation pattern in different quality-fractioned sperm populations of the same individual. The latter finding is particularly relevant if we consider that different quality fractioned sperm subpopulations show differences in their structural features, metabolic and genomic profiles. We demonstrate, for the first time, that DNA methylation in normozoospermic men remains highly uniform regardless the quality of sperm subpopulations. In addition, our analysis provided both confirmatory and novel data concerning the sperm DNA methylome, including its peculiar features in respect to somatic and cancer cells. Our description about a highly polarized sperm DNA methylation profile, the clearly distinct genomic and functional organization of hypo- versus hypermethylated loci as well as the association of histone-enriched hypomethylated loci with embryonic development, which we now extended also to hypomethylated piRNAs-linked genes, provides solid basis for future basic and clinical research.
Project description:Data about the entire sperm DNA methylome are limited to two sperm donors whereas studies dealing with a greater number of subjects focused only on a few genes or were based on low resolution arrays. This implies that information about what we can consider as a normal sperm DNA methylome and whether it is stable among different normozoospermic individuals is still missing. The definition of the DNA methylation profile of normozoospermic men, the entity of inter-individual variability and the epigenetic characterization of quality-fractioned sperm subpopulations in the same subject (intra-individual variability) are relevant for a better understanding of pathological conditions. We addressed these questions by using the high resolution Infinium 450K methylation array and compared normal sperm DNA methylomes against somatic cells. Our study, based on the largest number of subjects (n = 8) ever considered for such a large number of CpGs (n = 487,517), provided clear evidence for i) a highly conserved DNA methylation profile among normozoospermic subjects; ii) a stable sperm DNA methylation pattern in different quality-fractioned sperm populations of the same individual. The latter finding is particularly relevant if we consider that different quality fractioned sperm subpopulations show differences in their structural features, metabolic and genomic profiles. We demonstrate, for the first time, that DNA methylation in normozoospermic men remains highly uniform regardless the quality of sperm subpopulations. In addition, our analysis provided both confirmatory and novel data concerning the sperm DNA methylome, including its peculiar features in respect to somatic and cancer cells. Our description about a highly polarized sperm DNA methylation profile, the clearly distinct genomic and functional organization of hypo- versus hypermethylated loci as well as the association of histone-enriched hypomethylated loci with embryonic development, which we now extended also to hypomethylated piRNAs-linked genes, provides solid basis for future basic and clinical research. Bisulphite converted DNA from the 26 normal sperm and 2 somatic cell samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip v1.2
Project description:To determine if disease can modify aging patterns in an affected tissue without altering the aging patterns of other tissues, blood and semen of individuals with oligozoospermia (n=10) were compared to the blood and semen of individuals with normozoospermia (n=24). The Horvath and Jenkins age calculators were utilized to predict the epigenetic age of blood and sperm through the use of DNA methylation. Using these calculators, it was found that sperm of oligozoospermic men were predicted to be significantly older than the sperm of normozoospermic men; however, there was not a significant epigenetic age difference in blood. These results lead to the conclusion that tissue specific aging is occurring in sperm of oligozoospermic individuals but not in unaffected somatic tissues (in our case, blood).
Project description:Alterations in the presence of sperm RNAs have been identified using microarrays in teratozoospermic (abnormal morphology) or other types of infertile patients. However, so far no studies had been reported on the sperm RNA content using microarrays in asthenozoospermic patients (low motility). We started the present project to with the goal to characterize the RNA expression in asthenozoospermic infertile patients as compared to normozoospermic fertile controls. We selected four normal fertile donors and four severe asthenozoospermic infertile patients. Equal amounts of RNA were extracted from the sperm samples, subjected to different quality controls and hybridized to the Affymetrix U133 Plus version 2 arrays.
Project description:Genome wide DNA methylation differences in umbilical cord blood (UCB) of preterm and term born neonates. The Illumina 450K Human DNA methylation Beadchip was used to obtain the DNA methylation profiles of 12 preterm and 12 term UCB samples across 450,000 CpGs. 2 samples were removed due to failed quality control, and BMIQ normalization was done with 11 preterm and 11 term samples.
Project description:Analysis of ejaculated spermatozoav from normozoospermic men and asthenozoospermic men. Some of genes were up-regulated or down-regulated in asthenozoospermia, and their abnormal expression were the causes of the impaired sperm motility. Results provide insight into the mechanisms by which asthenozoospermia is controlled. We used microarrays to detail the global programme of gene expression of ejaculated spermatozoa between normozoospermic and asthenozoospermic men and identified distinct classes of genes expressed differentially in two groups. The liquefied semen samples from normozoospermic and asthenozoospermic men were purified by Percoll on a discontinuous density gradients for RNA extraction and hybridization on Affymetrix microarrays. 30 sperm samples of each group were pooled to abtain enough total RNA.
Project description:Analysis of ejaculated spermatozoav from normozoospermic men and asthenozoospermic men. Some of genes were up-regulated or down-regulated in asthenozoospermia, and their abnormal expression were the causes of the impaired sperm motility. Results provide insight into the mechanisms by which asthenozoospermia is controlled. We used microarrays to detail the global programme of gene expression of ejaculated spermatozoa between normozoospermic and asthenozoospermic men and identified distinct classes of genes expressed differentially in two groups.