Tet1 Is Dispensable for Maintaining Pluripotency and Its Loss Is Compatible with Embryonic and Postnatal Development

Human papillomavirus (HPV) infection is the world's most common sexually transmitted infection and is responsible for most cases of cervical cancer. Previous studies of global gene expression changes induced by HPV infection have focused on the cancerous stages of infection, and therefore, not much is known about global gene expression changes at early preneoplastic stages of infection. We show for the first time the global gene expression changes during early-stage HPV16 infection in cervical tissue using 3-dimensional organotypic raft cultures, which produce high levels of progeny virions. cDNA microarray analysis showed that a total of 594 genes were upregulated and 651 genes were downregulated at least 1.5-fold with HPV16 infection. Gene ontology analysis showed that biological processes including cell cycle progression and DNA metabolism were upregulated, while skin development, immune response, and cell death were downregulated with HPV16 infection in cervical keratinocytes. Individual genes were selected for validation at the transcriptional and translational levels, including UBC, which was central to the protein association network of immune response genes, and top downregulated genes RPTN, SERPINB4, KRT23, and KLK8 In particular, KLK8 and SERPINB4 were shown to be upregulated in cancer, which contrasts with the gene regulation during the productive replication stage. Organotypic raft cultures, which allow full progression of the HPV life cycle, allowed us to identify novel gene modulations and potential therapeutic targets of early-stage HPV infection in cervical tissue. Additionally, our results suggest that early-stage productive infection and cancerous stages of infection are distinct disease states expressing different host transcriptomes.IMPORTANCE Persistent HPV infection is responsible for most cases of cervical cancer. The transition from precancerous to cancerous stages of HPV infection is marked by a significant reduction in virus production. Most global gene expression studies of HPV infection have focused on the cancerous stages. Therefore, little is known about global gene expression changes at precancerous stages. For the first time, we measured global gene expression changes at the precancerous stages of HPV16 infection in human cervical tissue producing high levels of virus. We identified a group of genes that are typically overexpressed in cancerous stages to be significantly downregulated at the precancerous stage. Moreover, we identified significantly modulated genes that have not yet been studied in the context of HPV infection. Studying the role of these genes in HPV infection will help us understand what drives the transition from precancerous to cancerous stages and may lead to the development of new therapeutic targets.

Environmental estrogens are ubiquitous in the environment and can cause detrimental effects on male reproduction. In fish, a multitude of effects from environmental estrogens have been observed including altered courting behavior and fertility, sex reversal, and gonadal histopathology. However, few studies in fish assess the impacts of estrogenic exposure on a physiological endpoint, such as reproduction, as well as the associated morphologic response and underlying global gene expression changes. This study assessed the implications of a 14 day sub-chronic exposure of ethinylestradiol (EE2; 1.0 or 10.0 µg/L EE2) on male medaka fertility, testicular histology and testicular gene expression. The findings demonstrate that a 14 day exposure to EE2 induced impaired male reproductive capacity and time- and dose-dependent alterations in testicular morphology and gene expression. The average fertilization rate/day following the exposure for control, 1.0 and 10.0 µg/L EE2 was 91.3% (±4.4), 62.8% (±8.3) and 28.8% (±5.8), respectively. The testicular morphologic alterations included increased germ cell apoptosis, decreased germinal epithelium and thickening of the interstitium. These changes were highly associated with testicular gene expression changes using a medaka-specific microarray. A pathway analysis of the differentially expressed genes emphasized genes and pathways associated with apoptosis, cell cycle and proliferation, collagen production/extracellular matrix organization, hormone signaling, male reproduction and protein ubiquitination among others. These findings highlight the importance of anchoring global gonadal gene expression changes with morphology and ultimately with tissue/organ function.

BackgroundAutism spectrum disorder (ASD) is characterized as a neurodevelopmental disorder, and one of the main hypotheses regarding its cause is genetic factors. A previous meta-analysis of seven microarray studies and one RNA sequencing (RNA-seq) study using the blood of children with ASD identified dysregulation of gene expressions relevant to the immune system. In this study, we explored changes in global gene expression as the phenotype of ASD in the blood of adults with ASD.MethodsWe recruited an RNA-seq cohort (ASD vs. control; n = 6 each) and a replication cohort (ASD vs. control; n = 19 each) and conducted RNA-seq to explore changes in global gene expression. We then subjected the significantly up- and downregulated genes to gene ontology (GO) and core analyses. Weighted gene correlation network analysis (WGCNA) was performed with all 11,617 genes detected in RNA-seq to identify the ASD-specific gene network.ResultsIn total, 117 significantly up- and 83 significantly downregulated genes were detected in the ASD compared with the control group, respectively (p < 0.05 and q < 0.05). GO analysis revealed that the aberrant innate and adaptive immunity were more obvious in the 117 upregulated than in the 83 downregulated genes. WGCNA with core analysis revealed that one module including many immune-related genes was associated with the natural killer cell signaling pathway. In the results for the replication cohort, significant changes with same trend found in RNA-seq data were confirmed for MAFB (p = 0.046), RPSAP58 (p = 0.030), and G2MK (p = 0.004).LimitationsThe sample size was relatively small in both the RNA-seq and replication cohorts. This study examined the mRNA expression level, so the interaction between mRNA and protein remains unclear. The expression changes between children and adults with ASD were not compared because only adults with ASD were targeted.ConclusionsThe dysregulated gene expressions confirmed in the blood of adults with ASD were relevant to the dysfunction of innate and adaptive immunity. These findings may aid in understanding the pathogenesis of ASD.

S-adenosylmethionine Levels Regulate the Schwann Cell DNA Methylome

The aim of this study has been to identify important processes that regulate early stages of embryo development in conifers. Somatic embryogenesis in Picea abies has become a model system for studying embryology in conifers, providing a well-characterized sequence of developmental stages, resembling zygotic embryogeny, which can be synchronized by specific treatments, making it possible to collect a large number of somatic embryos at specific developmental stages. We have used this model to analyze global changes in gene expression during early stages of embryo development by generating an expression profile of 12,536 complementary DNA clones. This has allowed us to identify molecular events regulating putative processes associated with pattern formation during the earliest stages of embryogenesis which have not been identified on the molecular level in conifers before. We recognize notable changes in the expression of genes involved in regulating auxin biosynthesis and auxin response, gibberellin-mediated signaling, signaling between the embryo and the female gametophyte, tissue specification including the formation of boundary regions, and the switch from embryonic to vegetative development. In addition, our results confirm the involvement of previously described processes, including stress, differentiation of a protoderm, and programmed cell death.

The aim of this study has been to identify important processes that regulate early stages of embryo development in conifers. Somatic embryogenesis in Picea abies has become a model system for studying embryology in conifers, providing a well-characterized sequence of developmental stages, resembling zygotic embryogeny, which can be synchronized by specific treatments, making it possible to collect a large number of somatic embryos at specific developmental stages. We have used this model to analyze global changes in gene expression during early stages of embryo development by generating an expression profile of 12,536 complementary DNA clones. This has allowed us to identify molecular events regulating putative processes associated with pattern formation during the earliest stages of embryogenesis which have not been identified on the molecular level in conifers before. We recognize notable changes in the expression of genes involved in regulating auxin biosynthesis and auxin response, gibberellin-mediated signaling, signaling between the embryo and the female gametophyte, tissue specification including the formation of boundary regions, and the switch from embryonic to vegetative development. In addition, our results confirm the involvement of previously described processes, including stress, differentiation of a protoderm, and programmed cell death.

During different periods of mammalian development, global changes in gene expression occur. Developmental changes in global gene expression have been modeled as a restrictive process. To test the restriction model of global changes in gene expression, we have used embryonic stem (ES) cells as a model system for the early mammalian embryo. ES cells are pluripotent cells that can contribute to all cellular lineages of the developing mammalian fetus and are derived from early embryonic cells. Using this model system, we have studied a new class of RNAs called microRNAs that have been identified and shown to play a role in the direct regulation of messenger RNAs. Here we report the expression signature for 248 microRNAs in 13 independent murine ES cells, embryoid bodies, and somatic tissues. The expression profile for 248 mouse microRNAs was determined for embryonic stem cells, embryoid bodies, mouse embryos, mature heart, lung, liver, kidney, and brain. Characteristic microRNA expression signatures were observed for each evaluated sample. When the characteristic microRNA signatures for developmentally ordered samples were compared, immature samples exhibited a less complex microRNA transcript profile than did mature samples. Our data support a progressive model of microRNA gene expression. Based on the progressive increase in complexity of micro- RNA expression, we hypothesize that the mammalian developmental program requires a temporal coupling of expression between microRNAs and messenger RNAs to enable the developmental potential observed in mammalian ontogeny.

BackgroundVirus infection induces the activation and suppression of global gene expression in the host. Profiling gene expression changes in the host may provide insights into the molecular mechanisms that underlie host physiological and phenotypic responses to virus infection. In this study, the Arabidopsis Affymetrix ATH1 array was used to assess global gene expression changes in Arabidopsis thaliana plants infected with Plum pox virus (PPV). To identify early genes in response to PPV infection, an Arabidopsis synchronized single-cell transformation system was developed. Arabidopsis protoplasts were transfected with a PPV infectious clone and global gene expression changes in the transfected protoplasts were profiled.ResultsMicroarray analysis of PPV-infected Arabidopsis leaf tissues identified 2013 and 1457 genes that were significantly (Q ≤ 0.05) up- (≥ 2.5 fold) and downregulated (≤ -2.5 fold), respectively. Genes associated with soluble sugar, starch and amino acid, intracellular membrane/membrane-bound organelles, chloroplast, and protein fate were upregulated, while genes related to development/storage proteins, protein synthesis and translation, and cell wall-associated components were downregulated. These gene expression changes were associated with PPV infection and symptom development. Further transcriptional profiling of protoplasts transfected with a PPV infectious clone revealed the upregulation of defence and cellular signalling genes as early as 6 hours post transfection. A cross sequence comparison analysis of genes differentially regulated by PPV-infected Arabidopsis leaves against uniEST sequences derived from PPV-infected leaves of Prunus persica, a natural host of PPV, identified orthologs related to defence, metabolism and protein synthesis. The cross comparison of genes differentially regulated by PPV infection and by the infections of other positive sense RNA viruses revealed a common set of 416 genes. These identified genes, particularly the early responsive genes, may be critical in virus infection.ConclusionGene expression changes in PPV-infected Arabidopsis are the molecular basis of stress and defence-like responses, PPV pathogenesis and symptom development. The differentially regulated genes, particularly the early responsive genes, and a common set of genes regulated by infections of PPV and other positive sense RNA viruses identified in this study are candidates suitable for further functional characterization to shed lights on molecular virus-host interactions.

The purpose of this study was to analyze global gene expression changes in serial tumor core biopsy specimens taken during neoadjuvant chemotherapy for primary breast cancer. Core biopsy specimens from tumors were obtained before treatment and 24 and/or 48 hours after treatment from 21 women who were beginning chemotherapy for breast cancer. RNA was extracted, and radiolabeled complementary DNA was synthesized. The complementary DNA probes were hybridized to high-density microarray membranes that contained more than 25,000 human sequence clones. Hierarchical cluster analysis was used to compare the degree of similarity between expression profiles. Twenty-five (45%) of the 56 available core specimens yielded sufficient quantity and quality RNA for microarray analysis. Microarray profiles were performed only on samples from patients with pretreatment and posttreatment specimens, resulting in serial data sets for five patients (14 specimens). The serial samples from individual patients clustered more closely than the samples taken from different patients. Analyses of the variance of individual gene expression showed that there were significantly fewer genes with fivefold differences in expression in an individual tumor at different times (average, 359 genes) versus pretreatment samples of different tumors (average, 732 genes). Patients with a good pathological response to treatment had gene patterns that clustered distinctly from those of poor responders. Significant transcriptional response occurred in all patients during therapy. Surprisingly, all patients had different genes change after chemotherapy, with no single gene having a significant expression change in all five patients. This is the first report to show global gene expression changes during chemotherapy in a human solid tumor. Comprehensive gene expression profiles of more than 25,000 genes can be obtained from core biopsy specimens. A remarkable diversity in transcriptional response was observed for individual cases. Further data are needed to determine whether gene profiling can predict response to chemotherapy.

IntroductionBreast cancer is the most common malignancy affecting women. Although the prognosis generally is good, a substantial number of patients still suffer from relapse, emphasizing the need for novel treatments. Smac mimetics were developed to facilitate cell death by blocking inhibitor of apoptosis proteins (IAPs). It has been suggested that TNF-related apoptosis inducing ligand (TRAIL) can be used together with Smac mimetics to induce cancer cell death. MethodsCell viability was studied with Trypan blue staining and Annexin V assay, siRNA was used to downregulate specific proteins, protein levels were estimated with Western blot, and mRNA levels were analyzed with qPCR, microarray and RNA-seq. For global expression, groups were compared with principal component analysis and the limma package in R. Gene enrichment was analyzed with Fisher's test. For other experiments, significance of difference was tested by one-way ANOVA, followed by Tukey's HSD test. ResultsThe combination of Smac mimetic LCL-161 and TRAIL induces an irreversible change in phenotype, but not cell death, of luminal MCF-7 breast cancer cells. The cells become small and circular and dissociate from each other and the effect could not be reversed by returning the cells to regular growth medium. The morphology change could be prevented by caspase inhibition using z-VAD-FMK and downregulation of caspase-8. Caspase-7 is also indicated to be of importance since downregulation of this caspase resulted in fewer morphologically changed cells. Enrichment analyses of changes in global gene expression demonstrated that genes associated with estrogen receptor (ER) signaling are downregulated, whereas nuclear factor kappa B- (NF-κB) and interferon- (IFN) driven genes are upregulated in altered cells. However, inhibition of these pathways did not influence the change in morphology. Induction of IFN-induced genes were potentiated but NF-ĸB-driven genes were slightly suppressed by caspase inhibition. ConclusionsThe results demonstrate that LCL-161 and TRAIL can irreversibly alter the MCF-7 breast cancer cell phenotype. However, the changes in morphology and global gene expression are mediated via separate pathways.

While our understanding of Ras signaling is significant and many of the signaling components and pathways activated by Ras have been delineated, it is also likely that much remains to be determined. The discovery of additional downstream effectors of Ras continues and reveals further diversity and complexity in the cytoplasmic signaling activities of Ras. The recent identification of PLC3 as a Ras effector links Ras activity directly to the actions of second messengers, calcium and diacylglycerol, that in turn cause pleotropic cellular responses. Conversely, some effectors of Ras (Nore1 and RASSF1) may promote apoptosis rather than oncogenesis. How these effectors may contribute to the mechanism of Ras-mediated oncogenesis will be important to establish. One major consequence of these diverse effector signaling events involves changes in gene expression. Some signaling events directly stimulate the activity of specific transcription factors and the number of these factors continues to increase. Other Ras-mediated signaling events, including DNA methylation or histone acetylation, may cause global changes in gene expression. The development and applications of methods, such as microarray analyses and functional proteomics, to evaluate global changes in gene or protein expression will further increase our knowledge of the gene targets of Ras. Hence, this area of Ras research will evolve rapidly in the coming years. The accumulation of information will certainly occur at a pace that greatly exceeds our ability to make sense of these observations. Nevertheless, our utilization of this information will facilitate important advances for understanding the role of Ras in oncogenesis and for the identification of novel therapeutic approaches for cancer diagnosis and treatment.

Transcriptome Analysis of Human Colon Caco-2 Cells Exposed to Sulforaphane

Global gene expression changes induced by prolonged cold ischemic stress and preservation method of breast cancer tissue

A fundamental question in biology is how genome-wide changes in gene expression are enacted in response to a finite stimulus. Recent studies have mapped changes in nucleosome localization, determined the binding preferences for individual transcription factors, and shown that the genome adopts a nonrandom structure in vivo. What remains unclear is how global changes in the proteins bound to DNA alter chromatin structure and gene expression. We have addressed this question in the mouse heart, a system in which global gene expression and massive phenotypic changes occur without cardiac cell division, making the mechanisms of chromatin remodeling centrally important. To determine factors controlling genomic plasticity, we used mass spectrometry to measure chromatin-associated proteins. We have characterized the abundance of 305 chromatin-associated proteins in normal cells and measured changes in 108 proteins that accompany the progression of heart disease. These studies were conducted on a high mass accuracy instrument and confirmed in multiple biological replicates, facilitating statistical analysis and allowing us to interrogate the data bioinformatically for modules of proteins involved in similar processes. Our studies reveal general principles for global shifts in chromatin accessibility: altered linker to core histone ratio; differing abundance of chromatin structural proteins; and reprogrammed histone post-translational modifications. Using small interfering RNA-mediated loss-of-function in isolated cells, we demonstrate that the non-histone chromatin structural protein HMGB2 (but not HMGB1) suppresses pathologic cell growth in vivo and controls a gene expression program responsible for hypertrophic cell growth. Our findings reveal the basis for alterations in chromatin structure necessary for genome-wide changes in gene expression. These studies have fundamental implications for understanding how global chromatin remodeling occurs with specificity and accuracy, demonstrating that isoform-specific alterations in chromatin structural proteins can impart these features.

Retinal cell fate specification from multipotent retinal progenitors is governed by dynamic changes in chromatin structure and gene expression. Methylation at cytosines in DNA (5mC) is actively regulated for proper control of gene expression and chromatin architecture. Numerous genes display active DNA demethylation across retinal development; a process that requires oxidation of 5mC to 5-hydroxymethylcytosine (5hmC) and is controlled by the ten-eleven translocation (TET) methylcytosine dioxygenase enzymes. Using an allelic series of conditional TET enzyme mutants in mice, we determine that DNA demethylation is required upstream of NRL and NR2E3 expression for the establishment of rod-photoreceptor fate. Using histological, behavioral, transcriptomic, and base-pair resolution DNA methylation analyses, we establish that inhibition of active DNA demethylation results in global changes in gene expression and methylation patterns that prevent photoreceptor precursors from adopting a rod-photoreceptor fate, instead producing a retina in which all photoreceptors specify as cones. Our results establish the TET enzymes and DNA demethylation as critical regulators of retinal development and cell fate specification, elucidating a novel mechanism required for the specification of rod-photoreceptors.