Hormonal Signal Amplification Mediates Environmental Conditions during Development and Controls an Irreversible Commitment to Adulthood

Many animals can choose between different developmental fates to maximize fitness. Despite the complexity of environmental cues and life history, different developmental fates are executed in a robust fashion. The nematode Caenorhabditis elegans serves as a powerful model to examine this phenomenon because it can adopt one of two developmental fates (adulthood or diapause) depending on environmental conditions. The steroid hormone dafachronic acid (DA) directs development to adulthood by regulating the transcriptional activity of the nuclear hormone receptor DAF-12. The known role of DA suggests that it may be the molecular mediator of environmental condition effects on the developmental fate decision, although the mechanism is yet unknown. We used a combination of physiological and molecular biology techniques to demonstrate that commitment to reproductive adult development occurs when DA levels, produced in the neuroendocrine XXX cells, exceed a threshold. Furthermore, imaging and cell ablation experiments demonstrate that the XXX cells act as a source of DA, which, upon commitment to adult development, is amplified and propagated in the epidermis in a DAF-12 dependent manner. This positive feedback loop increases DA levels and drives adult programs in the gonad and epidermis, thus conferring the irreversibility of the decision. We show that the positive feedback loop canalizes development by ensuring that sufficient amounts of DA are dispersed throughout the body and serves as a robust fate-locking mechanism to enforce an organism-wide binary decision, despite noisy and complex environmental cues. These mechanisms are not only relevant to C. elegans but may be extended to other hormonal-based decision-making mechanisms in insects and mammals

Peroxisome Proliferator–Activated Receptor-γ Mediates Bisphenol A Inhibition of FSH-Stimulated IGF-1, Aromatase, and Estradiol in Human Granulosa Cells

BackgroundBisphenol A (BPA), a chemical used as a plasticizer, is a potent endocrine disruptor that, even in low concentrations, disturbs normal development and functions of reproductive organs in different species.ObjectivesWe investigated whether BPA affects human ovarian granulosa cell function.MethodsWe treated KGN granulosa cells and granulosa cells from subjects undergoing in vitro fertilization (IVF) with follicle-stimulating hormone (FSH), BPA, or BPA plus FSH in a dose- and time-dependent manner. We then evaluated expression of insulin-like growth factor 1 (IGF-1), aromatase, and transcription factors known to mediate aromatase induction by FSH [including steroidogenic factor-1 (SF-1), GATA4, cAMP response element binding protein-1 (CREB-1), and peroxisome proliferator-activated receptor-gamma (PPARgamma)], as well as 17beta-estradiol (E2) secretion. KGN cells were transfected with a PPARgamma-containing vector, followed by assessment of aromatase and IGF-I expression.ResultsBPA reduced FSH-induced IGF-1 and aromatase expression and E2 secretion in a dose-dependent fashion. Similar effects on aromatase were observed in IVF granulosa cells. SF-1 and GATA4, but not CREB-1, were reduced after BPA treatment, although PPARgamma, an inhibitor of aromatase, was significantly up-regulated by BPA in a dose-dependent manner, with simultaneous decrease of aromatase. Overexpression of PPARgamma in KGN cells reduced FSH-stimulated aromatase and IGF-1 mRNAs, with increasing concentrations of the transfected expression vector, mimicking BPA action. Also, BPA reduced granulosa cell DNA synthesis without changing DNA fragmentation, suggesting that BPA does not induce apoptosis.ConclusionsOverall, the data demonstrate that BPA induces PPARgamma, which mediates down-regulation of FSH-stimulated IGF-1, SF-1, GATA4, aromatase, and E2 in human granulosa cells. These observations support a potential role of altered steroidogenesis and proliferation within the ovarian follicular compartment due to this endocrine disruptor

Chemosensitivity of IDH1-Mutated Gliomas Due to an Impairment in PARP1-Mediated DNA Repair

Mutations in isocitrate dehydrogenase (IDH) are the most prevalent genetic abnormalities in lower grade gliomas. The presence of these mutations in glioma is prognostic for better clinical outcomes with longer patient survival. In the present study, we found that defects in oxidative metabolism and 2-HG production confer chemosensitization in IDH1-mutated glioma cells. In addition, temozolomide (TMZ) treatment induced greater DNA damage and apoptotic changes in mutant glioma cells. The PARP1-associated DNA repair pathway was extensively compromised in mutant cells due to decreased NAD+ availability. Targeting the PARP DNA repair pathway extensively sensitized IDH1-mutated glioma cells to TMZ. Our findings demonstrate a novel molecular mechanism that defines chemosensitivity in IDH-mutated gliomas. Targeting PARP-associated DNA repair may represent a novel therapeutic strategy for gliomas

Aromatase expression is increased in BRCA1 mutation carriers

<p>Abstract</p> <p>Background</p> <p>Until recently, the molecular mechanisms explaining increased incidence of ovarian and breast cancers in carriers of <it>BRCA1 </it>gene mutations had not been clearly understood. Of significance is the finding that BRCA1 negatively regulates aromatase expression <it>in vitro</it>. Our objective was to characterise aromatase gene <it>(CYP19A1) </it>and its promoter expression in breast adipose and ovarian tissue in <it>BRCA1 </it>mutation carriers and unaffected controls.</p> <p>Methods</p> <p>We measured aromatase transcripts, total and promoter-specific (PII, PI.3, PI.4) in prophylactic oophorectomy or mastectomy, therapeutic mastectomy, ovarian and breast tissue from unaffected women.</p> <p>Results</p> <p>We demonstrate that the lack of functional BRCA1 protein correlates to higher aromatase levels in 85% of <it>BRCA1 </it>mutation carriers. This increase is mediated by aberrant transcriptional regulation of aromatase; in breast adipose by increases in promoter II/I.3 and I.4-specific transcripts; and in the ovary with elevation in promoter I.3 and II-specific transcripts.</p> <p>Conclusion</p> <p>Understanding the link between BRCA1 and aromatase is significant in terms of understanding why carcinogenesis is restricted to estrogen-producing tissues in <it>BRCA1 </it>mutation carriers.</p

The supragingival biofilm in early childhood caries: Clinical and laboratory protocols and bioinformatics pipelines supporting metagenomics, metatranscriptomics, and metabolomics studies of the oral microbiome

Early childhood caries (ECC) is a biofilm-mediated disease. Social, environmental, and behavioral determinants as well as innate susceptibility are major influences on its incidence; however, from a pathogenetic standpoint, the disease is defined and driven by oral dysbiosis. In other words, the disease occurs when the natural equilibrium between the host and its oral microbiome shifts toward states that promote demineralization at the biofilm-tooth surface interface. Thus, a comprehensive understanding of dental caries as a disease requires the characterization of both the composition and the function or metabolic activity of the supragingival biofilm according to well-defined clinical statuses. However, taxonomic and functional information of the supragingival biofilm is rarely available in clinical cohorts, and its collection presents unique challenges among very young children. This paper presents a protocol and pipelines available for the conduct of supragingival biofilm microbiome studies among children in the primary dentition, that has been designed in the context of a large-scale population-based genetic epidemiologic study of ECC. The protocol is being developed for the collection of two supragingival biofilm samples from the maxillary primary dentition, enabling downstream taxonomic (e.g., metagenomics) and functional (e.g., transcriptomics and metabolomics) analyses. The protocol is being implemented in the assembly of a pediatric precision medicine cohort comprising over 6000 participants to date, contributing social, environmental, behavioral, clinical, and biological data informing ECC and other oral health outcomes

MicroRNA Expression and Regulation in Human Ovarian Carcinoma Cells by Luteinizing Hormone

MicroRNAs have been widely-studied with regard to their aberrant expression and high correlation with tumorigenesis and progression in various solid tumors. With the major goal of assessing gonadotropin (luteinizing hormone, LH) contributions to LH receptor (LHR)-positive ovarian cancer cells, we have conducted a genome-wide transcriptomic analysis on human epithelial ovarian cancer cells to identify the microRNA-associated cellular response to LH-mediated activation of LHR.Human ovarian cancer cells (SKOV3) were chosen as negative control (LHR-) and stably transfected to express functional LHR (LHR+), followed by incubation with LH (0-20 h). At different times of LH-mediated activation of LHR the cancer cells were analyzed by a high-density Ovarian Cancer Disease-Specific-Array (DSA, ALMAC™), which profiled ∼ 100,000 transcripts with ∼ 400 non-coding microRNAs.In total, 65 microRNAs were identified to exhibit differential expression in either LHR expressing SKOV3 cells or LH-treated cells, a few of which have been found in the genomic fragile regions that are associated with abnormal deletion or amplification in cancer, such as miR-21, miR-101-1, miR-210 and miR-301a. By incorporating the dramatic expression changes observed in mRNAs, strong microRNA/mRNA regulatory pairs were predicted through statistical analyses coupled with collective computational prediction. The role of each microRNA was then determined through a functional analysis based on the highly-confident microRNA/mRNA pairs.The overall impact on the transcriptome-level expression indicates that LH may regulate apoptosis and cell growth of LHR+ SKOV3 cells, particularly by reducing cancer cell proliferation, with some microRNAs involved in regulatory roles

Extra- and intra-ovarian factors in polycystic ovary syndrome: impact on oocyte maturation and embryo developmental competence

background: Polycystic ovary syndrome (PCOS) is a common metabolic dysfunction and heterogeneous endocrine disorder in women of reproductive age. Although patients with PCOS are typically characterized by increased numbers of oocytes retrieved during IVF, they are often of poor quality, leading to lower fertilization, cleavage and implantation rates, and a higher miscarriage rate. methods: For this review, we searched the database MEDLINE (1950 to January 2010) and Google for all full texts and/or abstract articles published in English with content related to oocyte maturation and embryo developmental competence. results: The search showed that alteration of many factors may directly or indirectly impair the competence of maturating oocytes through endocrine and local paracrine/autocrine actions, resulting in a lower pregnancy rate in patients with PCOS. The extra-ovarian factors identified included gonadotrophins, hyperandrogenemia and hyperinsulinemia, although intra-ovarian factors included members of the epidermal, fibroblast, insulin-like and neurotrophin families of growth factors, as well as the cytokines. conclusions: Any abnormality in the extra- and/or intra-ovarian factors may negatively affect the granulosa cell-oocyte interaction, oocyte maturation and potential embryonic developmental competence, contributing to unsuccessful outcomes for patients with PCOS who are undergoing assisted reproduction.Obstetrics &amp; GynecologyReproductive BiologySCI(E)PubMed49REVIEW117-331