Group B streptococcus exploits vaginal epithelial exfoliation for ascending infection

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Abstract

Thirteen percent of pregnancies result in preterm birth or stillbirth, accounting for fifteen million preterm births and three and a half million deaths annually. A significant cause of these adverse pregnancy outcomes is in utero infection by vaginal microorganisms. To establish an in utero infection, vaginal microbes enter the uterus by ascending infection; however, the mechanisms by which this occurs are unknown. Using both in vitro and murine models of vaginal colonization and ascending infection, we demonstrate how a vaginal microbe, group B streptococcus (GBS), which is frequently associated with adverse pregnancy outcomes, uses vaginal exfoliation for ascending infection. GBS induces vaginal epithelial exfoliation by activation of integrin and β-catenin signaling. However, exfoliation did not diminish GBS vaginal colonization as reported for other vaginal microbes. Rather, vaginal exfoliation increased bacterial dissemination and ascending GBS infection, and abrogation of exfoliation reduced ascending infection and improved pregnancy outcomes. Thus, for some vaginal bacteria, exfoliation promotes ascending infection rather than preventing colonization. Our study provides insight into mechanisms of ascending infection by vaginal microbes.

Authors

Jay Vornhagen, Blair Armistead, Verónica Santana-Ufret, Claire Gendrin, Sean Merillat, Michelle Coleman, Phoenicia Quach, Erica Boldenow, Varchita Alishetti, Christina Leonhard-Melief, Lisa Y. Ngo, Christopher Whidbey, Kelly S. Doran, Chad Curtis, Kristina M. Adams Waldorf, Elizabeth Nance, Lakshmi Rajagopal

Constitutively active follicle-stimulating hormone receptor enables androgen-independent spermatogenesis

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Abstract

Spermatogenesis is regulated by the 2 pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This process is considered impossible without the absolute requirement of LH-stimulated testicular testosterone (T) production. The role of FSH remains unclear because men and mice with inactivating FSH receptor (FSHR) mutations are fertile. We revisited the role of FSH in spermatogenesis using transgenic mice expressing a constitutively strongly active FSHR mutant in a LH receptor–null (LHR-null) background. The mutant FSHR reversed the azoospermia and partially restored fertility of Lhr–/– mice. The finding was initially ascribed to the residual Leydig cell T production. However, when T action was completely blocked with the potent antiandrogen flutamide, spermatogenesis persisted. Hence, completely T-independent spermatogenesis is possible through strong FSHR activation, and the dogma of T being a sine qua non for spermatogenesis may need modification. The mechanism for the finding appeared to be that FSHR activation maintained the expression of Sertoli cell genes considered androgen dependent. The translational message of our findings is the possibility of developing a new strategy of high-dose FSH treatment for spermatogenic failure. Our findings also provide an explanation of molecular pathogenesis for Pasqualini syndrome (fertile eunuchs; LH/T deficiency with persistent spermatogenesis) and explain how the hormonal regulation of spermatogenesis has shifted from FSH to T dominance during evolution.

Authors

Olayiwola O. Oduwole, Hellevi Peltoketo, Ariel Poliandri, Laura Vengadabady, Marcin Chrusciel, Milena Doroszko, Luna Samanta, Laura Owen, Brian Keevil, Nafis A. Rahman, Ilpo T. Huhtaniemi

H3K27me3 dynamics dictate evolving uterine states in pregnancy and parturition

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Abstract

Uncovering the causes of pregnancy complications such as preterm labor requires greater insight into how the uterus remains in a noncontractile state until term and then surmounts this state to enter labor. Here, we show that dynamic generation and erasure of the repressive histone modification tri-methyl histone H3 lysine 27 (H3K27me3) in decidual stromal cells dictate both elements of pregnancy success in mice. In early gestation, H3K27me3-induced transcriptional silencing of select gene targets ensured uterine quiescence by preventing the decidua from expressing parturition-inducing hormone receptors, manifesting type 1 immunity, and most unexpectedly, generating myofibroblasts and associated wound-healing responses. In late gestation, genome-wide H3K27 demethylation allowed for target gene upregulation, decidual activation, and labor entry. Pharmacological inhibition of H3K27 demethylation in late gestation not only prevented term parturition, but also inhibited delivery while maintaining pup viability in a noninflammatory model of preterm parturition. Immunofluorescence analysis of human specimens suggested that similar regulatory events might occur in the human decidua. Together, these results reveal the centrality of regulated gene silencing in the uterine adaptation to pregnancy and suggest new areas in the study and treatment of pregnancy disorders.

Authors

Patrice Nancy, Johan Siewiera, Gabrielle Rizzuto, Elisa Tagliani, Ivan Osokine, Priyanka Manandhar, Igor Dolgalev, Caterina Clementi, Aristotelis Tsirigos, Adrian Erlebacher

Polycomb subunit BMI1 determines uterine progesterone responsiveness essential for normal embryo implantation

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Abstract

Natural and synthetic progestogens have been commonly used to prevent recurrent pregnancy loss in women with inadequate progesterone secretion or reduced progesterone sensitivity. However, the clinical efficacy of progesterone and its analogs for maintaining pregnancy is variable. Additionally, the underlying cause of impaired endometrial progesterone responsiveness during early pregnancy remains unknown. Here, we demonstrated that uterine-selective depletion of BMI1, a key component of the polycomb repressive complex-1 (PRC1), hampers uterine progesterone responsiveness and derails normal uterine receptivity, resulting in implantation failure in mice. We further uncovered genetic and biochemical evidence that BMI1 interacts with the progesterone receptor (PR) and the E3 ligase E6AP in a polycomb complex–independent manner and regulates the PR ubiquitination that is essential for normal progesterone responsiveness. A close association of aberrantly low endometrial BMI1 expression with restrained PR responsiveness in women who had previously had a miscarriage indicated that the role of BMI1 in endometrial PR function is conserved in mice and in humans. In addition to uncovering a potential regulatory mechanism of BMI1 that ensures normal endometrial progesterone responsiveness during early pregnancy, our findings have the potential to help clarify the underlying causes of spontaneous pregnancy loss in women.

Authors

Qiliang Xin, Shuangbo Kong, Junhao Yan, Jingtao Qiu, Bo He, Chan Zhou, Zhangli Ni, Haili Bao, Lin Huang, Jinhua Lu, Guoliang Xia, Xicheng Liu, Zi-Jiang Chen, Chao Wang, Haibin Wang

Transcription factors SOHLH1 and SOHLH2 coordinate oocyte differentiation without affecting meiosis I

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Abstract

Following migration of primordial germ cells to the genital ridge, oogonia undergo several rounds of mitotic division and enter meiosis at approximately E13.5. Most oocytes arrest in the dictyate (diplotene) stage of meiosis circa E18.5. The genes necessary to drive oocyte differentiation in parallel with meiosis are unknown. Here, we have investigated whether expression of spermatogenesis and oogenesis bHLH transcription factor 1 (Sohlh1) and Sohlh2 coordinates oocyte differentiation within the embryonic ovary. We found that SOHLH2 protein was expressed in the mouse germline as early as E12.5 and preceded SOHLH1 protein expression, which occurred circa E15.5. SOHLH1 protein appearance at E15.5 correlated with SOHLH2 translocation from the cytoplasm into the nucleus and was dependent on SOHLH1 expression. NOBOX oogenesis homeobox (NOBOX) and LIM homeobox protein 8 (LHX8), two important regulators of postnatal oogenesis, were coexpressed with SOHLH1. Single deficiency of Sohlh1 or Sohlh2 disrupted the expression of LHX8 and NOBOX in the embryonic gonad without affecting meiosis. Sohlh1-KO infertility was rescued by conditional expression of the Sohlh1 transgene after the onset of meiosis. However, Sohlh1 or Sohlh2 transgene expression could not rescue Sohlh2-KO infertility due to a lack of Sohlh1 or Sohlh2 expression in rescued mice. Our results indicate that Sohlh1 and Sohlh2 are essential regulators of oocyte differentiation but do not affect meiosis I.

Authors

Yong-Hyun Shin, Yu Ren, Hitomi Suzuki, Kayla J. Golnoski, Hyo won Ahn, Vasil Mico, Aleksandar Rajkovic

The SO(H)L(H) “O” drivers of oocyte growth and survival but not meiosis I

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Abstract

The spermatogenesis/oogenesis helix-loop-helix (SOHLH) proteins SOHLH1 and SOHLH2 play important roles in male and female reproduction. Although previous studies indicate that these transcriptional regulators are expressed in and have in vivo roles in postnatal ovaries, their expression and function in the embryonic ovary remain largely unknown. Because oocyte differentiation is tightly coupled with the onset of meiosis, it is of significant interest to determine how early oocyte transcription factors regulate these two processes. In this issue of the JCI, Shin and colleagues report that SOHLH1 and SOHLH2 demonstrate distinct expression patterns in the embryonic ovary and interact with each other and other oocyte-specific transcription factors to regulate oocyte differentiation. Interestingly, even though there is a rapid loss of oocytes postnatally in ovaries with combined loss of Sohlh1 and Sohlh2, meiosis is not affected and proceeds normally.

Authors

T. Rajendra Kumar

Egress of sperm autoantigen from seminiferous tubules maintains systemic tolerance

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Abstract

Autoimmune responses to meiotic germ cell antigens (MGCA) that are expressed on sperm and testis occur in human infertility and after vasectomy. Many MGCA are also expressed as cancer/testis antigens (CTA) in human cancers, but the tolerance status of MGCA has not been investigated. MGCA are considered to be uniformly immunogenic and nontolerogenic, and the prevailing view posits that MGCA are sequestered behind the Sertoli cell barrier in seminiferous tubules. Here, we have shown that only some murine MGCA are sequestered. Nonsequestered MCGA (NS-MGCA) egressed from normal tubules, as evidenced by their ability to interact with systemically injected antibodies and form localized immune complexes outside the Sertoli cell barrier. NS-MGCA derived from cell fragments that were discarded by spermatids during spermiation. They egressed as cargo in residual bodies and maintained Treg-dependent physiological tolerance. In contrast, sequestered MGCA (S-MGCA) were undetectable in residual bodies and were nontolerogenic. Unlike postvasectomy autoantibodies, which have been shown to mainly target S-MGCA, autoantibodies produced by normal mice with transient Treg depletion that developed autoimmune orchitis exclusively targeted NS-MGCA. We conclude that spermiation, a physiological checkpoint in spermatogenesis, determines the egress and tolerogenicity of MGCA. Our findings will affect target antigen selection in testis and sperm autoimmunity and the immune responses to CTA in male cancer patients.

Authors

Kenneth S.K. Tung, Jessica Harakal, Hui Qiao, Claudia Rival, Jonathan C.H. Li, Alberta G.A. Paul, Karen Wheeler, Patcharin Pramoonjago, Constance M. Grafer, Wei Sun, Robert D. Sampson, Elissa W.P. Wong, Prabhakara P. Reddi, Umesh S. Deshmukh, Daniel M. Hardy, Huanghui Tang, C. Yan Cheng, Erwin Goldberg

Loss of microRNA-7a2 induces hypogonadotropic hypogonadism and infertility

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Abstract

MicroRNAs (miRNAs) are negative modulators of gene expression that fine-tune numerous biological processes. miRNA loss-of-function rarely results in highly penetrant phenotypes, but rather, influences cellular responses to physiologic and pathophysiologic stresses. Here, we have reported that a single member of the evolutionarily conserved miR-7 family, miR-7a2, is essential for normal pituitary development and hypothalamic-pituitary-gonadal (HPG) function in adulthood. Genetic deletion of mir-7a2 causes infertility, with low levels of gonadotropic and sex steroid hormones, small testes or ovaries, impaired spermatogenesis, and lack of ovulation in male and female mice, respectively. We found that miR-7a2 is highly expressed in the pituitary, where it suppresses golgi glycoprotein 1 (GLG1) expression and downstream bone morphogenetic protein 4 (BMP4) signaling and also reduces expression of the prostaglandin F2a receptor negative regulator (PTGFRN), an inhibitor of prostaglandin signaling and follicle-stimulating hormone (FSH) and luteinizing hormone (LH) secretion. Our results reveal that miR-7a2 critically regulates sexual maturation and reproductive function by interconnecting miR-7 genomic circuits that regulate FSH and LH synthesis and secretion through their effects on pituitary prostaglandin and BMP4 signaling.

Authors

Kashan Ahmed, Mary P. LaPierre, Emanuel Gasser, Rémy Denzler, Yinjie Yang, Thomas Rülicke, Jukka Kero, Mathieu Latreille, Markus Stoffel

Kisspeptin modulates sexual and emotional brain processing in humans

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Abstract

BACKGROUND. Sex, emotion, and reproduction are fundamental and tightly entwined aspects of human behavior. At a population level in humans, both the desire for sexual stimulation and the desire to bond with a partner are important precursors to reproduction. However, the relationships between these processes are incompletely understood. The limbic brain system has key roles in sexual and emotional behaviors, and is a likely candidate system for the integration of behavior with the hormonal reproductive axis. We investigated the effects of kisspeptin, a recently identified key reproductive hormone, on limbic brain activity and behavior.

METHODS. Using a combination of functional neuroimaging and hormonal and psychometric analyses, we compared the effects of kisspeptin versus vehicle administration in 29 healthy heterosexual young men.

RESULTS. We demonstrated that kisspeptin administration enhanced limbic brain activity specifically in response to sexual and couple-bonding stimuli. Furthermore, kisspeptin’s enhancement of limbic brain structures correlated with psychometric measures of reward, drive, mood, and sexual aversion, providing functional significance. In addition, kisspeptin administration attenuated negative mood.

CONCLUSIONS. Collectively, our data provide evidence of an undescribed role for kisspeptin in integrating sexual and emotional brain processing with reproduction in humans. These results have important implications for our understanding of reproductive biology and are highly relevant to the current pharmacological development of kisspeptin as a potential therapeutic agent for patients with common disorders of reproductive function.

FUNDING. National Institute for Health Research (NIHR), Wellcome Trust (Ref 080268), and the Medical Research Council (MRC).

Authors

Alexander N. Comninos, Matthew B. Wall, Lysia Demetriou, Amar J. Shah, Sophie A. Clarke, Shakunthala Narayanaswamy, Alexander Nesbitt, Chioma Izzi-Engbeaya, Julia K. Prague, Ali Abbara, Risheka Ratnasabapathy, Victoria Salem, Gurjinder M. Nijher, Channa N. Jayasena, Mark Tanner, Paul Bassett, Amrish Mehta, Eugenii A. Rabiner, Christoph Hönigsperger, Meire Ribeiro Silva, Ole Kristian Brandtzaeg, Elsa Lundanes, Steven Ray Wilson, Rachel C. Brown, Sarah A. Thomas, Stephen R. Bloom, Waljit S. Dhillo

Early pregnancy vitamin D status and risk of preeclampsia

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Abstract

BACKGROUND. Low vitamin D status in pregnancy was proposed as a risk factor of preeclampsia.

METHODS. We assessed the effect of vitamin D supplementation (4,400 vs. 400 IU/day), initiated early in pregnancy (10–18 weeks), on the development of preeclampsia. The effects of serum vitamin D (25-hydroxyvitamin D [25OHD]) levels on preeclampsia incidence at trial entry and in the third trimester (32–38 weeks) were studied. We also conducted a nested case-control study of 157 women to investigate peripheral blood vitamin D–associated gene expression profiles at 10 to 18 weeks in 47 participants who developed preeclampsia.

RESULTS. Of 881 women randomized, outcome data were available for 816, with 67 (8.2%) developing preeclampsia. There was no significant difference between treatment (N = 408) or control (N = 408) groups in the incidence of preeclampsia (8.08% vs. 8.33%, respectively; relative risk: 0.97; 95% CI, 0.61–1.53). However, in a cohort analysis and after adjustment for confounders, a significant effect of sufficient vitamin D status (25OHD ≥30 ng/ml) was observed in both early and late pregnancy compared with insufficient levels (25OHD <30 ng/ml) (adjusted odds ratio, 0.28; 95% CI, 0.10–0.96). Differential expression of 348 vitamin D–associated genes (158 upregulated) was found in peripheral blood of women who developed preeclampsia (FDR <0.05 in the Vitamin D Antenatal Asthma Reduction Trial [VDAART]; P < 0.05 in a replication cohort). Functional enrichment and network analyses of this vitamin D–associated gene set suggests several highly functional modules related to systematic inflammatory and immune responses, including some nodes with a high degree of connectivity.

CONCLUSIONS. Vitamin D supplementation initiated in weeks 10–18 of pregnancy did not reduce preeclampsia incidence in the intention-to-treat paradigm. However, vitamin D levels of 30 ng/ml or higher at trial entry and in late pregnancy were associated with a lower risk of preeclampsia. Differentially expressed vitamin D–associated transcriptomes implicated the emergence of an early pregnancy, distinctive immune response in women who went on to develop preeclampsia.

TRIAL REGISTRATION. ClinicalTrials.gov NCT00920621.

FUNDING. Quebec Breast Cancer Foundation and Genome Canada Innovation Network. This trial was funded by the National Heart, Lung, and Blood Institute. For details see Acknowledgments.

Authors

Hooman Mirzakhani, Augusto A. Litonjua, Thomas F. McElrath, George O’Connor, Aviva Lee-Parritz, Ronald Iverson, George Macones, Robert C. Strunk, Leonard B. Bacharier, Robert Zeiger, Bruce W. Hollis, Diane E. Handy, Amitabh Sharma, Nancy Laranjo, Vincent Carey, Weilliang Qiu, Marc Santolini, Shikang Liu, Divya Chhabra, Daniel A. Enquobahrie, Michelle A. Williams, Joseph Loscalzo, Scott T. Weiss