Project description:BACKGROUND: In previous studies using candidate gene approaches, low sperm count (oligospermia) has been associated with altered sperm mRNA content and DNA methylation in both imprinted and non-imprinted genes. We performed a genome-wide analysis of sperm DNA methylation and mRNA content to test for associations with sperm function. METHODS AND RESULTS: Sperm DNA and mRNA were isolated from 21 men with a range of semen parameters presenting to a tertiary male reproductive health clinic. DNA methylation was measured with the Illumina Infinium array at 27,000 CpG loci. Unsupervised clustering of methylation data differentiated the 21 sperm samples by their motility values. Recursively partitioned mixture modeling (RPMM) of methylation data resulted in four distinct methylation profiles that were significantly associated with sperm motility (P=0.01). Linear models of microarray analysis (LIMMA) was performed based on motility and identified 9,189 CpG loci with significantly altered methylation (Q<0.05) in the low motility samples, with many loci located in genes associated with subfertility and epigenetic regulation. In the low motility samples, the majority of disrupted CpG loci (80%) were hypomethylated. Of the aberrantly methylated CpGs, 194 were associated with imprinted genes almost equally distributed into hypermethylated (predominantly paternally expressed) and hypomethylated (predominantly maternally expressed) groups. Sperm mRNA was measured with the Human Gene 1.0 ST Affymetrix GeneChip Array. LIMMA analysis based on motility identified 20 candidate transcripts as differentially expressed in low motility sperm, including HDAC1 (NCBI 3065), SIRT3 (NCBI 23410), and DNMT3A (NCBI 1788). Altered expression of these epigenetic regulatory genes was associated with RPMM DNA methylation class. CONCLUSIONS: Using integrative genome-wide approaches to study epigenetic and gene expression patterns in human sperm we identified CpG methylation profiles and mRNA alterations associated with low sperm motility, and that low motility sperm may have aberrant genome-wide hypomethylation due to excess HDAC1 activity. See summary above
Project description:Small noncoding RNAs (sncRNA) are becoming recognized for their participation in a diverse range of cellular functions. In this study, their global characterization in human spermatozoa from donors with proven fertility was undertaken. Reads were analyzed in two classes, those mapping to unique locations and those that could be aligned to up to 10 genomic locations. All libraries showed comparable distribution of reads between intergenic, intronic and exonic genomic regions. Analysis of the sequences revealed the presence of multiple small RNA classes. The miRNAs retained in spermatozoa were found to be associated with promoter regions, suggestive of a role at the transcriptional level. Piwi-interacting sncRNAs as well as repeat-associated small RNAs were identified for the first time in mature spermatozoa from a mammalian species. Human spermatozoa retain a multifaceted population of small non-coding RNAs. Their presence is consistent with the view that they may function to stabilize the genome as part of the confrontation and consolidation of the genomes at fertilization. Examination of sperm samples from 3 individuals, sequenced individually
Project description:Herein, we constructed a human lectin microarray with 60 human lectin and lectin-like proteins. All of the lectins and lectin-like proteins were purified from yeast, and most showed binding to human glycans. To demonstrate the applicability of the human lectin microarray, human sperm were probed on the microarray and strong bindings were observed for several lectins, including galectin-1, 7, 8, GalNAc-T6, and ERGIC-53 (LMAN1). These bindings were validated by flow cytometry and fluorescence immunostaining. Further, mass spectrometry analysis showed that galectin-1 binds several membrane proteins including HSP90. Finally, functional assays showed that binding of galectin-8 could significantly enhance the acrosome reaction within human sperms. To our knowledge, this is the first construction of a human lectin microarray, and we anticipate it will find wide use for a range of human or mammalian studies, alone or in combination with plant lectin microarrays.
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:The small non-coding RNAs (sncRNAs) are considered as postranscriptional key regulators of male germ cell development. In addition to microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs), other sncRNAs generated from small nucleolar RNAs (snoRNAs), tRNAs or rRNAs processing may also play important regulatory roles in spermatogenesis. By next generation sequencing (NGS), we characterized the different sncRNA populations detected at three milestone stages in male germ differentiation: primordial germ cells (PGCs) at 13.5 dpc, pubertal spermatogonia cells, and mature spermatozoa. In order to assess the potential transmission of the sncRNAs through the mature spermatozoa during fertilization, the sncRNA population detected in male germ cells was also compared with sncRNAs detected in unfertilized mouse oocytes and zygotes. Combining the data obtained by NGS and microarrays from whole PGC and spermatogonia transcriptome, we defined the potential regulatory roles of specific miRNAs and their validated targets. Similar to miRNAs, both the small RNAs derived from snoRNAs and the piRNAs, could be involved in the postranscriptional regulation of mRNA transcripts during the male germ development. Finally, our results strongly suggest that the small RNAs-derived from tRNAs and rRNAs are interacting with PIWI proteins, and specifically with MILI. These new classes of piRNAs are not generated by the ping-pong pathway and could be the source of primary piRNAs. Comparative analysis from deep sequencing of piRNAs and endo-siRNAs in mouse oocytes, spermatozoa and zygotes
Project description:Sperm samples were extracted from adult A. aegypti male seminal vesicles. Semen samples were extracted from bursa of recently mated bursa of N15 labeled females. The goal was to differentiate between the contribution of seminal fluid proteins and sperm proteins in the semen transfered to the female. Our results yield insights into the molecular function, genome organization, regulation, and evolution of sperm proteins and SFPs in this important disease vector.
Project description:Current human reproductive risk assessment methods rely on semen and serum hormone analyses, which are not easily comparable to the histopathological endpoints and mating studies used in animal testing. Because of these limitations, there is a need to develop universal evaluations that reliably reflect male reproductive function. We hypothesized that toxicant-induced testicular injury can be detected in sperm using mRNA transcripts as indicators of insult. To test this, we exposed adult male Fischer 344 rats to low doses of model testicular toxicants and classically characterized the testicular injury while simultaneously evaluating sperm mRNA transcripts from the same animals. Overall, this study aimed to: 1) identify sperm transcripts altered after exposure to the model testicular toxicant, 2,5-hexanedione (HD) using microarrays; 2) expand on the HD-induced transcript changes in a comprehensive time course experiment using qRT-PCR arrays; and 3) test these injury indicators after exposure to another model testicular toxicant, carbendazim (CBZ). Microarray analysis of HD-treated adult Fischer 344 rats identified 128 altered sperm mRNA transcripts when compared to control using linear models of microarray analysis (q < 0.05). All transcript alterations disappeared after 3 months of post-exposure recovery. In the time course experiment, time-dependent alterations were observed for 12 candidate transcripts selected from the microarray data based upon fold change and biological relevance, and 8 of these transcripts remained significantly altered after the 3-month recovery period (p < 0.05). In the last experiment, 8 candidate transcripts changed after exposure to CBZ (p < 0.05). The two testicular toxicants produced distinct molecular signatures with only 4 overlapping transcripts between them, each occurring in opposite directions. Overall, these results suggest that sperm mRNA transcripts are indicators of low dose toxicant-induced testicular injury in the rat. Rats were exposed to sub-chronic low doses of the Sertoli cell toxicant 2,5-hexanedione (HD) or water (control for HD) for 3 months. Some rats in each group underwent 3 months of post-exposure recovery.
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:Mammalian embryonic stem (ES) cells and sperm exhibit unusual chromatin packaging that plays important roles in cellular function. Here, we extend a recently developed technique, based on deep paired-end sequencing of lightly digested chromatin, to assess footprints of nucleosomes and other DNA-binding proteins genome-wide in murine ES cells and sperm. In ES cells, we recover well-characterized features of chromatin such as promoter nucleosome depletion, and further identify widespread footprints of sequence-specific DNA-binding proteins such as CTCF, which we validate in knockdown studies. We document global differences in nuclease accessibility between ES cells and sperm, finding that the majority of histone retention in sperm preferentially occurs in large gene-poor genomic regions, with only a small subset of nucleosomes being retained over promoters of developmental regulators. Finally, we describe evidence that CTCF remains associated with the genome in mature sperm, where it could play a role in organizing the sperm genome. We use Micrococcal Nuclease (MNase) to map chromatin structure in mouse ES cells and sperm. Specifically, we generate paired-end deep-sequencing libraries that are able to distinguish DNA digestion products by size, thus allowing us to simultaneously map nucleosomes as well as other DNA-binding proteins such as transcription factors.
Project description:Here, we demonstrate that Nematostella vectensis, Ciona intestinalis, Apis mellifera, and B. mori, show two distinct populations of genes differentiated by gene-body CpG density. Genome-scale DNA methylation profiles for A. mellifera spermatozoa reveal CpG-poor genes are methylated in the germ line, as predicted by the depletion of CpGs. We find an evolutionarily conserved distinction between CpG-poor and -rich genes: the former are associated with basic biological processes, the latter with more specialized functions. This distinction is strikingly similar to that recently observed between euchromatin-associated genes in Drosophila that contain intragenic histone 3 lysine 36 trimethylation (H3K36me3) and those that do not, even though Drosophila doesn’t display CpG density bimodality or methylation. We confirm that a significant number of CpG-poor genes in N. vectensis, C. intestinalis, A. mellifera and B. mori are orthologs of H3K36me3- rich genes in Drosophila. We propose that over evolutionary time, gene-body H3K36me3 has influenced gene-body DNA methylation levels, and consequently the gene-body CpG density bimodality characteristic of invertebrates that harbor CpG methylation. Examination of DNA methylation in Apis Mellifera sperm