Purpose: the goal of this project is to study the effects of the PFOS (perfluorooctanesulfonate) in the transcriptome profiling (RNA-seq) of exposed zebrafish larvae. Methods: Total RNA was isolated from the samples using AllPrep DNA/RNA Mini Kit (Qiagen, CA, USA) as described by the manufacturer. Three high quality sample per condition were chosen to the mRNA enrichment using KAPA Stranded mRNA-Seq Kit Illumina® Platforms (Kapa Biosystems). Transcriptomic profiles were generated by deep sequencing using Illumina TruSeq SBS Kit v3-HS (pair-ended; 2x76bp) on a HiSeq2000 sequencing system. Image analysis, base calling and quality scoring of the run were processed using the manufacturer's software Real Time Analysis (RTA 1.13.48) and followed by generation of FASTQ sequence files by CASAVA. Statistical analysis: RNA-seq reads were aligned to the D. rerio reference genome (GRCz10) using STAR version 2.5.1b . Genes annotated in GRCz10.84 were quantified using RSEM version 1.2.28 with default parameters. Differential expression analysis between all PFOS conditions was performed with the DESeq2 (v.1.10.1) R package with the Likelihood ratio test option. ANOVA-PLS was performed on the normalized data using the lmdme package in R (v. 1.0.136, R Core Team). Results: We generated on average 39 million paired-end reads for each sample and identified aproximatelly 24500 transcripts. 1434 differentially expressed genes (DEGs) were detected which could be divided in 2 clusters including 767 and 667 genes, respectively. Affected metabolic pathways were analyzed from the DEGs: lipid transport and metabolism, protein ubiquination, antigen processing, immune system, apoptosis, trans-membrane, cell matrix, Zn-ion binding, cytokines and JAK-STAT signaling pathways', among others, were down or upregulated. Conclusions: Our results suggest a complex, multiple endocrine disruption-like toxic effects at a concentrations well bellow the 1 mg/L, considered as the LOAEC/NOAEC for many of the macroscopic effects traditionally linked to PFOS toxicity in zebrafish embryos. While our results confirm the known effect of PFOS in lipid metabolism, we found a clear decrease on expression of many genes related to natural immunity and defense against infections. We propose that this transcriptional pattern may be a marker for the immunotoxic effects of PFOS and other related substances in fish and other vertebrates, including humans. We concluded that our analysis allowed us the identification of underlying molecular mechanisms occurring simultaneously at the exposed animals. While this approach is very useful to analyze the effects of compounds, like PFOS, able to interact with different cellular targets, we believe that it can be also applied to the characterization of the different toxic components present in complex natural mixtures. Overall design: Whole embryo (5 dpf; wild type zebrafish) mRNA profiles of 4 groups (control, 0.03, 0.3 and 1 ppm of PFOS) were generated by deep sequencing, in triplicate, using Illumina TruSeq SBS Kit v3-HS (pair-ended) on a HiSeq2000 sequencing system.
Unravelling the mechanisms of PFOS toxicity by combining morphological and transcriptomic analyses in zebrafish embryos.
Age, Subject
View SamplesBivalent histone domains have been proposed to contribute to pluripotency in embryonic stem cells, suggesting an epigenetic mechanism may regulate stem cell behavior in general. Here we compare histone modifications in two other stem cells derived from the blastocyst. We show that extraembryonic stem cells have little repressive lysine 27 trimethylation and few bivalent domains. Thus, bivalent domains are not a common mechanism for maintaining the undifferentiated state in blastocyst-derived stem cells and alternative mechanisms must mediate transcriptional repression in extraembryonic cells. We show that lysine 9 trimethylation, but not DNA methylation, is likely to fulfill this role. Intriguingly, although we do detect bivalent domains in pluripotent cells in the early mouse embryo, the epigenetic status of extraembryonic cells does not entirely reflect their in vitro stem cell counterparts. Therefore, differences in epigenetic regulation between lineage progenitors in vivo and in vitro may arise during selection for self-renewal in vitro.
Distinct histone modifications in stem cell lines and tissue lineages from the early mouse embryo.
Cell line
View SamplesWhile the reprogramming factors OCT4, SOX2, KLF4, and MYC (OSKM) can reactivate the pluripotency network in terminally differentiated cells, they also regulate expression of non-pluripotency genes in other contexts, such as the mouse primitive endoderm. The primitive endoderm is an extraembryonic lineage established alongside the pluripotent epiblast in the blastocyst, and is the progenitor pool for extraembryonic endoderm stem (XEN) cells. Several studies have shown that endodermal genes are upregulated in fibroblasts undergoing reprogramming, although whether endodermal genes promote or inhibit acquisition of pluripotency is unclear. We show that, in fibroblasts undergoing conventional reprogramming, OSKM-induced expression of endodermal genes leads to formation of induced XEN (iXEN) cells, which possess key properties of blastocyst-derived XEN cells, including morphology, transcription profile, self-renewal, and multipotency. Our data show that iXEN cells arise in parallel to iPS cells, indicating that OSKM are sufficient to drive cells to two distinct fates during reprogramming. Overall design: Sequence-based mRNA transcriptional profiling of three different cell lines (MEF, XEN, iXEN) with multiple biological replicates, under two different growth medium conditions (ESC medium, XEN medium) for XEN and iXEN cells.
OSKM Induce Extraembryonic Endoderm Stem Cells in Parallel to Induced Pluripotent Stem Cells.
Specimen part, Treatment, Subject
View SamplesStearoyl-CoA desaturase (SCD) is the rate-limiting enzyme catalyzing the conversion of saturated fatty acids palmitate and stearate to monounsaturated fatty acids palmitoleate and oleate. During adipocyte differentiation, SCD expression increases concomitantly with several transcription factors and lipogenic genes.
Inhibition of stearoyl-CoA desaturase-1 in differentiating 3T3-L1 preadipocytes upregulates elongase 6 and downregulates genes affecting triacylglycerol synthesis.
Specimen part, Treatment
View SamplesSaturated fatty acids (SFA) are widely thought to induce inflammation in adipose tissue (AT), while monounsaturated fatty acids (MUFA) are purported to have the opposite effect; however, it is unclear if individual SFA and MUFA behave similarly. Our goal was to examine adipocyte transcriptional networks regulated by individual SFA (palmitic acid, PA; stearic acid, SA) and MUFA (palmitoleic acid, PMA; oleic acid, OA).
Individual saturated and monounsaturated fatty acids trigger distinct transcriptional networks in differentiated 3T3-L1 preadipocytes.
Specimen part
View SamplesES cell lines were established from mouse embryos, which were homozygous for the Trim33-flox allele and carried the UbcCreERT2 transgene. Cells were cultured without feeder cells in the presence of LIF and 2i. Embryoid bodies (EBs) were generated using the ATCC protocol on low attachment dishes under differentiating conditions. EBs were induced with Tamoxifen at day 4 and harvested at day 7. Overall design: Investigate differentially expressed genes in control and Trim33-deficient embryoid bodies derived from mouse embryonic stem cells
Trim33 is required for appropriate development of pre-cardiogenic mesoderm.
Specimen part, Cell line, Subject, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A condensin-like dosage compensation complex acts at a distance to control expression throughout the genome.
No sample metadata fields
View SamplesIn many species, a dosage compensation complex (DCC) is targeted to X chromosomes of one sex to equalize levels of X gene products between males (1X) and females (2X). Here we identify cis-acting regulatory elements that target the C. elegans X chromosome for repression by the DCC. The DCC binds to discrete, dispersed sites on X of two types. rex sites recruit the DCC in an autonomous, DNA sequence-dependent manner using a 12 bp consensus motif that is enriched on X. This motif is critical for DCC binding, is clustered in rex sites, and confers much of X-chromosome specificity. Motif variants enriched on X by 3.8-fold or more are highly predictive (95%) for rex sites. In contrast, dox sites lack the X-enriched variants and cannot bind the DCC when detached from X. dox sites are more prevalent than rex sites and, unlike rex sites, reside preferentially in promoters of some expressed genes. These findings fulfill predictions for a targeting model in which the DCC binds to recruitment sites on X and disperses to discrete sites lacking autonomous recruitment ability. To relate DCC binding to function, we identified dosage-compensated and non-compensated genes on X. Unexpectedly, many genes of both types have bound DCC, but many do not, suggesting the DCC acts over long distances to repress X gene expression. Remarkably, the DCC binds to autosomes, but at far fewer sites and rarely at consensus motifs. DCC disruption causes opposite effects on expression of X and autosomal genes. The DCC thus acts at a distance to impact expression throughout the genome.
A condensin-like dosage compensation complex acts at a distance to control expression throughout the genome.
No sample metadata fields
View SamplesThe function of Structural maintenance of chromosome flexible domain containing 1 (Smchd1) was examined during mouse preimplantation development using an siRNA knockdown approach. Transient SMCHD1 deficiency during the period between fertilization and morula/early blastocyst stage compromised embryo viability and resulted in reduced cell number, reduced embryo diameter, and reduced nuclear volumes at the morula stage. RNAseq analysis of Smchd1 knockdown morulae revealed aberrant increases in expression of mRNAs related to the trophoblast lineage, indicating SMCHD1 inhibits trophoblast lineage gene expression and promotes inner cell mass formation. siRNA knockdown also reduced expression of cell proliferation genes, including S-phase kinase-associated protein 2 (Skp2). Smchd1 expression was elevated in Caudal type homeobox transcription factor 2 (Cdx2)-/- blastocysts, indicating enriched expression, and further indicating a role in inner cell mass development. These results indicate that Smchd1 plays dual roles in the preimplantation embryo, promoting a lineage-appropriate pattern of gene expression supporting inner cell mass formation, whilst controlling lineage formation and gene expression in the trophectoderm. Overall design: Effects of SMCHD1 siRNA knockdown were tested in mouse embryos
Novel key roles for structural maintenance of chromosome flexible domain containing 1 (Smchd1) during preimplantation mouse development.
Treatment, Subject
View SamplesGene expression analyis of two hESCs, two human neonatal fibroblasts, and four human iPSCs generated with retroviral transduction using the OSKM cocktail.
Human induced pluripotent stem cells harbor homoplasmic and heteroplasmic mitochondrial DNA mutations while maintaining human embryonic stem cell-like metabolic reprogramming.
Specimen part, Cell line
View Samples