Loss of Endometrial Plasticity in Recurrent Pregnancy Loss.

Menstruation drives cyclic activation of endometrial progenitor cells, tissue regeneration, and maturation of stromal cells, which differentiate into specialized decidual cells prior to and during pregnancy. Aberrant responsiveness of human endometrial stromal cells (HESCs) to deciduogenic cues is strongly associated with recurrent pregnancy loss (RPL), suggesting a defect in cellular maturation. MeDIP-seq analysis of HESCs did not reveal gross perturbations in CpG methylation in RPL cultures, although quantitative differences were observed in or near genes that are frequently deregulated in vivo. However, RPL was associated with a marked reduction in methylation of defined CA-rich motifs located throughout the genome but enriched near telomeres. Non-CpG methylation is a hallmark of cellular multipotency. Congruently, we demonstrate that RPL is associated with a deficiency in endometrial clonogenic cell populations. Loss of epigenetic stemness features also correlated with intragenic CpG hypomethylation and reduced expression of HMGB2, coding high mobility group protein 2. We show that knockdown of this sequence-independent chromatin protein in HESCs promotes senescence and impairs decidualization, exemplified by blunted time-dependent secretome changes. Our findings indicate that stem cell deficiency and accelerated stromal senescence limit the differentiation capacity of the endometrium and predispose for pregnancy failure.

The clock protein period 2 synchronizes mitotic expansion and decidual transformation of human endometrial stromal cells.

Implantation requires coordinated interactions between the conceptus and surrounding decidual cells, but the involvement of clock genes in this process is incompletely understood. Circadian oscillations are predicated on transcriptional-translational feedback loops, which balance the activities of the transcriptional activators CLOCK (circadian locomotor output cycles kaput) and brain muscle arnt-like 1 and repressors encoded by PER (Period) and Cryptochrome genes. We show that loss of PER2 expression silences circadian oscillations in decidualizing human endometrial stromal cells (HESCs). Down-regulation occurred between 12 and 24 hours following differentiation and coincided with reduced CLOCK binding to a noncanonical E-box enhancer in the PER2 promoter. RNA sequencing revealed that premature inhibition of PER2 by small interfering RNA knockdown leads to a grossly disorganized decidual response. Gene ontology analysis highlighted a preponderance of cell cycle regulators among the 1121 genes perturbed upon PER2 knockdown. Congruently, PER2 inhibition abrogated mitotic expansion of differentiating HESCs by inducing cell cycle block at G2/M. Analysis of 70 midluteal endometrial biopsies revealed an inverse correlation between PER2 transcript levels and the number of miscarriages in women suffering reproductive failure (Spearman rank test, ρ = -0.3260; P = 0.0046). Thus, PER2 synchronizes endometrial proliferation with initiation of aperiodic decidual gene expression; uncoupling of these events may cause recurrent pregnancy loss.

Genomic and proteomic characterization of two novel siphovirus infecting the sedentary facultative epibiont cyanobacterium Acaryochloris marina.

Acaryochloris marina is a symbiotic species of cyanobacteria that is capable of utilizing far-red light. We report the characterization of the phages A-HIS1 and A-HIS2, capable of infecting Acaryochloris. Morphological characterization of these phages places them in the family Siphoviridae. However, molecular characterization reveals that they do not show genetic similarity with any known siphoviruses. While the phages do show synteny between each other, the nucleotide identity between the phages is low at 45-67%, suggesting they diverged from each other some time ago. The greatest number of genes shared with another phage (a myovirus infecting marine Synechococcus) was four. Unlike most other cyanophages and in common with the Siphoviridae infecting Synechococcus, no photosynthesis-related genes were found in the genome. CRISPR (clustered regularly interspaced short palindromic repeats) spacers from the host Acaryochloris had partial matches to sequences found within the phages, which is the first time CRISPRs have been reported in a cyanobacterial/cyanophage system. The phages also encode a homologue of the proteobacterial RNase T. The potential function of RNase T in the mark-up or digestion of crRNA hints at a novel mechanism for evading the host CRISPR system.

Brown and white adipose tissues: intrinsic differences in gene expression and response to cold exposure in mice.

Brown adipocytes dissipate energy, whereas white adipocytes are an energy storage site. We explored the plasticity of different white adipose tissue depots in acquiring a brown phenotype by cold exposure. By comparing cold-induced genes in white fat to those enriched in brown compared with white fat, at thermoneutrality we defined a "brite" transcription signature. We identified the genes, pathways, and promoter regulatory motifs associated with "browning," as these represent novel targets for understanding this process. For example, neuregulin 4 was more highly expressed in brown adipose tissue and upregulated in white fat upon cold exposure, and cell studies showed that it is a neurite outgrowth-promoting adipokine, indicative of a role in increasing adipose tissue innervation in response to cold. A cell culture system that allows us to reproduce the differential properties of the discrete adipose depots was developed to study depot-specific differences at an in vitro level. The key transcriptional events underpinning white adipose tissue to brown transition are important, as they represent an attractive proposition to overcome the detrimental effects associated with metabolic disorders, including obesity and type 2 diabetes.

Assessment of myometrial transcriptome changes associated with spontaneous human labour by high-throughput RNA-seq.

The transition of the human uterus from a quiescent to a contractile state takes place over a number of weeks. On such biological time scales, cellular phenotype is modified by changes in the transcriptome, which in turn is under the control of the underlying endocrine, paracrine, and biophysical processes resulting from the ongoing pregnancy. In this study, we characterize the transition of the human myometrial transcriptome at term from not in labour (NIL) to in labour (LAB) using high throughput RNA sequencing (RNA-seq). RNA was isolated from the myometrium of uterine biopsies from patients at term who were not in labour (n = 5) and at term in spontaneous labour (n = 5) without augmentation. A total of 143.6 million separate reads were sequenced, achieving, on average, ∼13 times coverage of the expressed human transcriptome per sample. Principal component analysis indicated that the NIL and LAB transcriptomes could be distinguished as two distinct clusters. A comparison of the NIL and LAB groups, using three different statistical approaches (baySeq, edgeR, and DESeq), demonstrated an overlap of 764 differentially expressed genes. A comparison with currently available microarray data revealed only a partial overlap in differentially expressed genes. We conclude that the described RNA-seq data sets represent the first fully annotated catalogue of expressed mRNAs in human myometrium. When considered together, the full expression repertoire and the differentially expressed gene sets should provide an excellent resource for formulating new hypotheses of physiological function, as well as the discovery of novel therapeutic targets.

Discovery of cyanophage genomes which contain mitochondrial DNA polymerase.

DNA polymerase γ is a family A DNA polymerase responsible for the replication of mitochondrial DNA in eukaryotes. The origins of DNA polymerase γ have remained elusive because it is not present in any known bacterium, though it has been hypothesized that mitochondria may have inherited the enzyme by phage-mediated nonorthologous displacement. Here, we present an analysis of two full-length homologues of this gene, which were found in the genomes of two bacteriophages, which infect the chlorophyll-d containing cyanobacterium Acaryochloris marina. Phylogenetic analyses of these phage DNA polymerase γ proteins show that they branch deeply within the DNA polymerase γ clade and therefore share a common origin with their eukaryotic homologues. We also found homologues of these phage polymerases in the environmental Community Cyberinfrastructure for Advanced Microbial Ecology Research and Analysis (CAMERA) database, which fell in the same clade. An analysis of the CAMERA assemblies containing the environmental homologues together with the filter fraction metadata indicated some of these assemblies may be of bacterial origin. We also show that the phage-encoded DNA polymerase γ is highly transcribed as the phage genomes are replicated. These findings provide data that may assist in reconstructing the evolution of mitochondria.

Outcomes Based on Plasma Biomarkers for the Phase 3 CELESTIAL Trial of Cabozantinib versus Placebo in Advanced Hepatocellular Carcinoma.

INTRODUCTION: Cabozantinib, an inhibitor of MET, AXL, and VEGF receptors, significantly improved overall survival (OS) and progression-free survival (PFS) versus placebo in patients with previously treated advanced hepatocellular carcinoma (HCC). In this exploratory analysis, outcomes were evaluated according to plasma biomarker levels. METHODS: Baseline plasma levels were evaluated for MET, AXL, VEGFR2, HGF, GAS6, VEGF-A, PlGF, IL-8, EPO, ANG2, IGF-1, VEGF-C, and c-KIT for 674/707 randomized patients; and Week 4 levels were evaluated for MET, AXL, VEGFR2, HGF, GAS6, VEGF-A, PlGF, IL-8, and EPO for 614 patients. OS and PFS were analyzed by baseline levels as dichotomized or continuous variables and by on-treatment changes at Week 4 as continuous variables; biomarkers were considered potentially prognostic if p < 0.05 and predictive if p < 0.05 for the interaction between treatment and the biomarker. Multivariable analyses adjusting for clinical covariates were also performed. RESULTS: In the placebo group, high levels of MET, HGF, GAS6, IL-8, and ANG2 and low levels of IGF-1 were associated with shorter OS in univariate and multivariable analyses; these associations were also observed for MET, IL-8, and ANG2 in the cabozantinib group. Hazard ratios for OS and PFS favored cabozantinib over the placebo at low and high baseline levels for all biomarkers. No baseline biomarkers were predictive of a treatment benefit. Cabozantinib promoted pharmacodynamic changes in several biomarkers, including increases in VEGF-A, PlGF, AXL, and GAS6 levels and decreases in VEGFR2 and HGF levels; these changes were not associated with OS or PFS. CONCLUSION: Cabozantinib improved OS and PFS versus placebo at high and low baseline concentrations for all biomarkers analyzed. Low baseline levels of MET, HGF, GAS6, IL-8, and ANG2 and high levels of IGF-1 were identified as potential favorable prognostic biomarkers for survival in previously treated advanced HCC. Although cabozantinib promoted pharmacodynamic changes in several biomarkers, these changes were not associated with survival.

The GPR120 agonist TUG-891 promotes metabolic health by stimulating mitochondrial respiration in brown fat.

Brown adipose tissue (BAT) activation stimulates energy expenditure in human adults, which makes it an attractive target to combat obesity and related disorders. Recent studies demonstrated a role for G protein-coupled receptor 120 (GPR120) in BAT thermogenesis. Here, we investigated the therapeutic potential of GPR120 agonism and addressed GPR120-mediated signaling in BAT We found that activation of GPR120 by the selective agonist TUG-891 acutely increases fat oxidation and reduces body weight and fat mass in C57Bl/6J mice. These effects coincided with decreased brown adipocyte lipid content and increased nutrient uptake by BAT, confirming increased BAT activity. Consistent with these observations, GPR120 deficiency reduced expression of genes involved in nutrient handling in BAT Stimulation of brown adipocytes in vitro with TUG-891 acutely induced O2 consumption, through GPR120-dependent and GPR120-independent mechanisms. TUG-891 not only stimulated GPR120 signaling resulting in intracellular calcium release, mitochondrial depolarization, and mitochondrial fission, but also activated UCP1. Collectively, these data suggest that activation of brown adipocytes with the GPR120 agonist TUG-891 is a promising strategy to increase lipid combustion and reduce obesity.

Pigment composition and adaptation in free-living and symbiotic strains of Acaryochloris marina.

Acaryochloris marina strains have been isolated from several varied locations and habitats worldwide demonstrating a diverse and dynamic ecology. In this study, the whole cell photophysiologies of strain MBIC11017, originally isolated from a colonial ascidian, and the free-living epilithic strain CCMEE5410 are analyzed by absorbance and fluorescence spectroscopy, laser scanning confocal microscopy, sodium dodecyl sulfate polyacrylamide gel electrophoresis and subsequent protein analysis. We demonstrate pigment adaptation in MBIC11017 and CCMEE5410 under different light regimes. We show that the higher the incident growth light intensity for both strains, the greater the decrease in their chlorophyll d content. However, the strain MBIC11017 loses its phycobiliproteins relative to its chlorophyll d content when grown at light intensities of 40 microE m(-2) s(-1) without shaking and 100 microE m(-2) s(-1) with shaking. We also conclude that phycobiliproteins are absent in the free-living strain CCMEE5410.

Allele-specific analysis of cell fusion-mediated pluripotent reprograming reveals distinct and predictive susceptibilities of human X-linked genes to reactivation.

BACKGROUND: Inactivation of one X chromosome is established early in female mammalian development and can be reversed in vivo and in vitro when pluripotency factors are re-expressed. The extent of reactivation along the inactive X chromosome (Xi) and the determinants of locus susceptibility are, however, poorly understood. Here we use cell fusion-mediated pluripotent reprograming to study human Xi reactivation and allele-specific single nucleotide polymorphisms (SNPs) to identify reactivated loci. RESULTS: We show that a subset of human Xi genes is rapidly reactivated upon re-expression of the pluripotency network. These genes lie within the most evolutionary recent segments of the human X chromosome that are depleted of LINE1 and enriched for SINE elements, predicted to impair XIST spreading. Interestingly, this cadre of genes displays stochastic Xi expression in human fibroblasts ahead of reprograming. This stochastic variability is evident between clones, by RNA-sequencing, and at the single-cell level, by RNA-FISH, and is not attributable to differences in repressive histone H3K9me3 or H3K27me3 levels. Treatment with the DNA demethylating agent 5-deoxy-azacytidine does not increase Xi expression ahead of reprograming, but instead reveals a second cadre of genes that only become susceptible to reactivation upon induction of pluripotency. CONCLUSIONS: Collectively, these data not only underscore the multiple pathways that contribute to maintaining silencing along the human Xi chromosome but also suggest that transcriptional stochasticity among human cells could be useful for predicting and engineering epigenetic strategies to achieve locus-specific or domain-specific human Xi gene reactivation.

Decidualization induces a secretome switch in perivascular niche cells of the human endometrium.

The endometrial perivascular microenvironment is rich in mesenchymal stem-like cells that express type 1 integral membrane protein Sushi domain containing 2 (SUSD2) but the role of these cells in the decidual transformation of this tissue in pregnancy is unknown. We used an antibody directed against SUSD2 (W5C5) to isolate perivascular (W5C5(+)) and nonperivascular (W5C5(-)) fibroblasts from mid-luteal biopsies. We show that SUSD2 expression, and hence the ratio of W5C5(+):W5C5(-) cells, changes in culture depending on cell-cell contact and activation of the Notch signaling pathway. RNA sequencing revealed that cultures derived from W5C5(+) progenitor cells remain phenotypically distinct by the enrichment of novel and established endometrial perivascular signature genes. In an undifferentiated state, W5C5(+)-derived cells produced lower levels of various chemokines and inflammatory modulators when compared with their W5C5(-) counterparts. This divergence in secretomes was switched and became more pronounced upon decidualization, which transformed perivascular W5C5(+) cells into the dominant source of a range of chemokines and cytokines, including leukemia inhibitory factor and chemokine (C-C motif) ligand 7. Our findings suggest that the decidual response is spatially organized at the embryo-maternal interface with differentiating perivascular cells establishing distinct cytokine and chemokine profiles that could potentially direct trophoblast toward maternal vessels and govern local immune responses in pregnancy.

Uterine selection of human embryos at implantation.

Human embryos frequently harbor large-scale complex chromosomal errors that impede normal development. Affected embryos may fail to implant although many first breach the endometrial epithelium and embed in the decidualizing stroma before being rejected via mechanisms that are poorly understood. Here we show that developmentally impaired human embryos elicit an endoplasmic stress response in human decidual cells. A stress response was also evident upon in vivo exposure of mouse uteri to culture medium conditioned by low-quality human embryos. By contrast, signals emanating from developmentally competent embryos activated a focused gene network enriched in metabolic enzymes and implantation factors. We further show that trypsin, a serine protease released by pre-implantation embryos, elicits Ca(2+) signaling in endometrial epithelial cells. Competent human embryos triggered short-lived oscillatory Ca(2+) fluxes whereas low-quality embryos caused a heightened and prolonged Ca(2+) response. Thus, distinct positive and negative mechanisms contribute to active selection of human embryos at implantation.

The inwardly rectifying K+ channel KIR7.1 controls uterine excitability throughout pregnancy.

Abnormal uterine activity in pregnancy causes a range of important clinical disorders, including preterm birth, dysfunctional labour and post-partum haemorrhage. Uterine contractile patterns are controlled by the generation of complex electrical signals at the myometrial smooth muscle plasma membrane. To identify novel targets to treat conditions associated with uterine dysfunction, we undertook a genome-wide screen of potassium channels that are enriched in myometrial smooth muscle. Computational modelling identified Kir7.1 as potentially important in regulating uterine excitability during pregnancy. We demonstrate Kir7.1 current hyper-polarizes uterine myocytes and promotes quiescence during gestation. Labour is associated with a decline, but not loss, of Kir7.1 expression. Knockdown of Kir7.1 by lentiviral expression of miRNA was sufficient to increase uterine contractile force and duration significantly. Conversely, overexpression of Kir7.1 inhibited uterine contractility. Finally, we demonstrate that the Kir7.1 inhibitor VU590 as well as novel derivative compounds induces profound, long-lasting contractions in mouse and human myometrium; the activity of these inhibitors exceeds that of other uterotonic drugs. We conclude Kir7.1 regulates the transition from quiescence to contractions in the pregnant uterus and may be a target for therapies to control uterine contractility.

Disordered IL-33/ST2 activation in decidualizing stromal cells prolongs uterine receptivity in women with recurrent pregnancy loss.

Decidualization renders the endometrium transiently receptive to an implanting blastocyst although the underlying mechanisms remain incompletely understood. Here we show that human endometrial stromal cells (HESCs) rapidly release IL-33, a key regulator of innate immune responses, upon decidualization. In parallel, differentiating HESCs upregulate the IL-33 transmembrane receptor ST2L and other pro-inflammatory mediators before mounting a profound anti-inflammatory response that includes downregulation of ST2L and increased expression of the soluble decoy receptor sST2. We demonstrate that HESCs secrete factors permissive of embryo implantation in mice only during the pro-inflammatory phase of the decidual process. IL-33 knockdown in undifferentiated HESCs was sufficient to abrogate this pro-inflammatory decidual response. Further, sequential activation of the IL-33/ST2L/sST2 axis was disordered in decidualizing HESCs from women with recurrent pregnancy loss. Signals from these cultures prolonged the implantation window but also caused subsequent pregnancy failure in mice. Thus, Il-33/ST2 activation in HESCS drives an autoinflammatory response that controls the temporal expression of receptivity genes. Failure to constrain this response predisposes to miscarriage by allowing out-of-phase implantation in an unsupportive uterine environment.