Modelling the contribution of hormonal and inflammatory pathways to term and preterm labour in the mouse

Labour onset results from a complex interplay between hormonal and inflammatory signals. Untimely activation of these pathways can cause preterm labour (PTL) and premature birth (<37 weeks of gestation), the primary cause of infant mortality. Throughout gestation, uterine quiescence is maintained by progesterone and its withdrawal at term induces pro-labour genes and activation of uterine contractions. Infection and inflammation are frequently associated with PTL. Recognition of bacteria by the maternal innate immune system involves activation of nuclear factor kappa-B (NFκB) and activator protein-1 (AP-1), which regulate inflammatory and pro-labour genes. The aim of this thesis was to determine the contribution of inflammatory and hormonal pathways to parturition in murine models by comparing molecular changes in myometrium throughout term gestation, PTL induced by lipopolysaccharide (LPS; inflammation-induced PTL), and RU486-induced PTL by progesterone withdrawal (non-inflammatory PTL). Term gestation was shown to involve sequential activation of NFκB and AP-1. Different LPS serotypes induced heterogeneous maternal and fetal responses in the LPS-induced PTL model. LPS O111:B4 caused the most severe phenotype of PTL within 7h and total fetal demise. This involved JNK/AP-1-mediated activation of uterine inflammation, without NFκB activation. TLR-4 ablation rescued this phenotype and JNK inhibition delayed PTL. RU486 caused PTL without modulation of inflammatory pathways. RNA-Seq was used to characterize dynamic uterine transcriptome changes antecedent to term labour or PTL (RU486 or LPS-induced). Strong similarity was observed within term gestation and RU486-induced PTL transcriptomes, while the LPS model involved distinctive inflammatory gene changes. Positive correlation was found between human and murine transcriptomes. This thesis shows that LPS-induced inflammation can override repressive effects of progesterone on pro-labour genes while abrogation of progesterone signalling prompts PTL without inflammatory gene activation. These data support the paradigm of a common terminal pathway of labour yet provides new evidence that inflammatory gene activation is not necessary for labour.Open Acces

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Canonical pathways enrichment calculated by Ingenuity Pathway Analysis. A total of 46 pathways were detected as significantly enriched with genes differentially expressed in the pairwise comparisons indicated in the first row of the table (P < 0.05). First column on the left indicates Gene Ontology name associated with the canonical pathway. Log10P values are reported for each pathway. (XLS 38 kb

Modeling hormonal and inflammatory contributions to preterm and term labor using uterine temporal transcriptomics

BACKGROUND: Preterm birth is now recognized as the primary cause of infant mortality worldwide. Interplay between hormonal and inflammatory signaling in the uterus modulates the onset of contractions; however, the relative contribution of each remains unclear. In this study we aimed to characterize temporal transcriptome changes in the uterus preceding term labor and preterm labor (PTL) induced by progesterone withdrawal or inflammation in the mouse and compare these findings with human data. METHODS: Myometrium was collected at multiple time points during gestation and labor from three murine models of parturition: (1) term gestation; (2) PTL induced by RU486; and (3) PTL induced by lipopolysaccharide (LPS). RNA was extracted and cDNA libraries were prepared and sequenced using the Illumina HiSeq 2000 system. Resulting RNA-Seq data were analyzed using multivariate modeling approaches as well as pathway and causal network analyses and compared against human myometrial transcriptome data. RESULTS: We identified a core set of temporal myometrial gene changes associated with term labor and PTL in the mouse induced by either inflammation or progesterone withdrawal. Progesterone withdrawal initiated labor without inflammatory gene activation, yet LPS activation of uterine inflammation was sufficient to override the repressive effects of progesterone and induce a laboring phenotype. Comparison of human and mouse uterine transcriptomic datasets revealed that human labor more closely resembles inflammation-induced PTL in the mouse. CONCLUSIONS: Labor in the mouse can be achieved through inflammatory gene activation yet these changes are not a requisite for labor itself. Human labor more closely resembles LPS-induced PTL in the mouse, supporting an essential role for inflammatory mediators in human “functional progesterone withdrawal.” This improved understanding of inflammatory and progesterone influence on the uterine transcriptome has important implications for the development of PTL prevention strategies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12916-016-0632-4) contains supplementary material, which is available to authorized users

TRIM28-dependent SUMOylation protects the adult ovary from activation of the testicular pathway

International audienceGonadal sexual fate in mammals is determined during embryonic development and must be actively maintained in adulthood. In the mouse ovary, oestrogen receptors and FOXL2 protect ovarian granulosa cells from transdifferentiation into Sertoli cells, their testicular counterpart. However, the mechanism underlying their protective effect is unknown. Here, we show that TRIM28 is required to prevent female-to-male sex reversal of the mouse ovary after birth. We found that upon loss of Trim28 , ovarian granulosa cells transdifferentiate to Sertoli cells through an intermediate cell type, different from gonadal embryonic progenitors. TRIM28 is recruited on chromatin in the proximity of FOXL2 to maintain the ovarian pathway and to repress testicular-specific genes. The role of TRIM28 in ovarian maintenance depends on its E3-SUMO ligase activity that regulates the sex-specific SUMOylation profile of ovarian-specific genes. Our study identifies TRIM28 as a key factor in protecting the adult ovary from the testicular pathway

The −KTS splice variant of WT1 is essential for ovarian determination in mice

IMPORTANT , l'article est en accès libre, le lien est sur le site http://ibv.unice.fr/research-team/chaboissier/ , il est surligné si on utilise Google Chrome http://ibv.unice.fr/research-team/chaboissier/#:~:text=https%3A//www.science.org/stoken/author%2Dtokens/ST%2D1527/fullInternational audienceSex determination in mammals depends on the differentiation of the supporting lineage of the gonads into Sertoli or pregranulosa cells that govern testis and ovary development, respectively. Although the Y-linked testis-determining gene Sry has been identified, the ovarian-determining factor remains unknown. In this study, we identified −KTS, a major, alternatively spliced isoform of the Wilms tumor suppressor WT1, as a key determinant of female sex determination. Loss of − KTS variants blocked gonadal differentiation in mice, whereas increased expression, as found in Frasier syndrome, induced precocious differentiation of ovaries independently of their genetic sex. In XY embryos, this antagonized Sry expression, resulting in male-to-female sex reversal. Our results identify −KTS as an ovarian-determining factor and demonstrate that its time of activation is critical in gonadal sex differentiation

Chemical Quest: general knowledge and popular culture quizzes about the elements in a board game for the class

Chemical Quest is an innovative trivia game based on the 102 elements of the periodic table from H to No, developed collaboratively by upper secondary school and university teachers with the aim of increasing the interest of young students (age 14–18) in chemistry. As part of the project, a software version of the game was successfully played in 24 classes. ‘Challenging, sometimes difficult, highly instructive, relaxing, captivating, ….’ are some of the positive comments by students and teachers. In addition, Chemical Quest was conceived to be adaptable since the rules can be modified and the cards can be selected to match the educational objective

Testis formation in XX individuals resulting from novel pathogenic variants in Wilms’ tumor 1 ( WT1 ) gene

International audienceSex determination in mammals is governed by antagonistic interactions of two genetic pathways, imbalance in which may lead to disorders/differences of sex development (DSD) in human. Among 46,XX individuals with testicular DSD (TDSD) or ovotesticular DSD (OTDSD), testicular tissue is present in the gonad. Although the testis-determining gene SRY is present in many cases, the etiology is unknown in most SRY-negative patients. We performed exome sequencing on 78 individuals with 46,XX TDSD/OTDSD of unknown genetic etiology and identified seven (8.97%) with heterozygous variants affecting the fourth zinc finger (ZF4) of Wilms' tumor 1 (WT1) (p.Ser478Thrfs*17, p.Pro481Leufs*15, p.Lys491Glu, p.Arg495Gln [x3], p.Arg495Gly). The variants were de novo in six families (P = 4.4 × 10-6), and the incidence of WT1 variants in 46,XX DSD is enriched compared to control populations (P < 1.8 × 10-4). The introduction of ZF4 mutants into a human granulosa cell line resulted in up-regulation of endogenous Sertoli cell transcripts and Wt1 Arg495Gly/Arg495Gly XX mice display masculinization of the fetal gonads. The phenotype could be explained by the ability of the mutated proteins to physically interact with and sequester a key pro-ovary factor β-CATENIN, which may lead to up-regulation of testis-specific pathway. Our data show that unlike previous association of WT1 and 46,XY DSD, ZF4 variants of WT1 are a relatively common cause of 46,XX TDSD/OTDSD. This expands the spectrum of phenotypes associated with WT1 variants and shows that the WT1 protein affecting ZF4 can function as a protestis factor in an XX chromosomal context