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Mohammed Hoque, Danny Chen, Rex A Hess, Feng-Qian Li, and Ken-Ichi Takemaru

Cilia are evolutionarily conserved microtubule-based structures that perform diverse biological functions. Cilia are assembled on basal bodies and anchored to the plasma membrane via distal appendages. In the male reproductive tract, multicilia in efferent ducts (EDs) move in a whip-like motion to prevent sperm agglutination. Previously, we demonstrated that the distal appendage protein CEP164 recruits Chibby1 (Cby1) to basal bodies to facilitate basal body docking and ciliogenesis. Mice lacking CEP164 in multiciliated cells (MCCs) (FoxJ1-Cre;CEP164fl/fl) show a significant loss of multicilia in the trachea, oviduct, and ependyma. In addition, we observed male sterility; however, the precise role of CEP164 in male fertility remained unknown. Here, we report that the seminiferous tubules and rete testis of FoxJ1-Cre;CEP164fl/fl mice exhibit substantial dilation, indicative of dysfunctional multicilia in the EDs. We found that multicilia were hardly detectable in the EDs of FoxJ1-Cre;CEP164fl/fl mice although FoxJ1-positive immature cells were present. Sperm aggregation and agglutination were commonly noticeable in the lumen of the seminiferous tubules and EDs of FoxJ1-Cre;CEP164fl/fl mice. In FoxJ1-Cre;CEP164fl/fl mice, the apical localization of Cby1 and the transition zone marker NPHP1 was severely diminished, suggesting basal body docking defects. TEM analysis of EDs further confirmed basal body accumulation in the cytoplasm of MCCs. Collectively, we conclude that male infertility in FoxJ1-Cre;CEP164fl/fl mice is caused by sperm agglutination and obstruction of EDs due to loss of multicilia. Our study, therefore, unravels an essential role of the distal appendage protein CEP164 in male fertility.

Open access

Dengfeng Bi, Jing Yao, Yu Wang, Guosong Qin, Yunting Zhang, Yanfang Wang, and Jianguo Zhao

An efficient mRNA knockdown strategy is needed to explore gene function in cells and embryos, especially to understand the process of maternal mRNA decay during early embryo development. Cas13, a novel RNA-targeting CRISPR effector protein, could bind and cleave complementary single-strand RNA, which has been employed for mRNA knockdown in mouse and human cells and RNA-virus interference in plants. Cas13 has not yet been reported to be used in pigs. In the current study, we explored the feasibility of CRISPR/Cas13d-mediated endogenous RNA knockdown in pigs. KDM5B, a histone demethylase of H3K4me3, was downregulated at the transcriptional level by 50% with CRISPR/Cas13d in porcine fibroblast cells. Knockdown of KDM5B-induced H3K4me3 expression and decreased the abundance of H3K27me3, H3K9me3, H3K4ac, H4K8ac, and H4K12ac. These changes affected cell proliferation and cell cycle. Furthermore, stable integration of the CRISPR/Cas13d system into the porcine genome resulted in the continuous expression of Cas13d and persistent knockdown of KDM5B. Finally, the RNA-targeting potential of Cas13d was further validated in porcine parthenogenetic embryos. By microinjection of Cas13d mRNA and gRNA targeting KDM5B into porcine oocytes, the expression of KDM5B was downregulated, the abundance of H3K4me3 increased as expected, and the expression of embryonic development-related genes was changed accordingly. These results indicate that CRISPR/Cas13d provides an easily programmable platform for spatiotemporal transcriptional manipulation in pigs.

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Lanting Chen, Fengrun Sun, Mengdie Li, Jinfeng Qian, Meirong Du, Dajin Li, and Songcun Wang

The T-box transcription factor protein eomesodermin (Eomes) is known for both homeostasis and function of effector and memory CD8+T cells. However, much less is known about the functional regulation of Eomes on CD8+ T cells during pregnancy. In the present study, we concluded the higher Eomes expression dCD8+T cells during normal early pregnancy. The number of Eomes+dCD8+T cells decreased in miscarriage. This Eomes+dCD8+T cell subset also expressed less growth-promoting factors, shifted toward pro-inflammatory phenotype in miscarriage. Primary Trophoblasts and HTR8/SVneo cell line could increase Eomes expression of dCD8+T cells from both normal early pregnancy and miscarriage, which might provide a new strategy for therapy to promote maternal–fetal tolerance and prevent pregnancy loss. These findings indicated that Eomes might be promising early warming targets of miscarriage. In addition, this study suggested that the reproductive safety must be a criterion considered in modulating the dose and function of Eomes in CD8+T cells to reverse T cell exhaustion.

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Tetsuhiro Yokonishi and Blanche Capel

Sertoli cells proliferate and construct seminiferous tubules during fetal life, then undergo differentiation and maturation in the prepubertal testes. In the adult testes, mature Sertoli cells maintain spermatogonia and support spermatogenesis during the entire lifetime. Although Sertoli-like cells have been derived from iPS cells, they tend to remain immature. To investigate whether Sertoli cells can spontaneously acquire the ability to support spermatogenesis when transferred into the adult testis, we transplanted mouse fetal testicular cells into a Sertoli-depleted adult testis. We found that donor E12.5, E14.5 and E16.5 Sertoli cells colonized adult seminiferous tubules and supported host spermatogenesis 2 months after transplantation, demonstrating that immature fetal Sertoli cells can undergo sufficient maturation in the adult testis to become functional. This technique will be useful to analyze the developmental process of Sertoli cell maturation and to investigate the potential of iPS-derived Sertoli cells to colonize, undergo maturation, and support spermatogenesis within the testis environment.

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Rodrigo A Carrasco, Carlos E Leonardi, Sergio Pezo, and Gregg P Adams

To elucidate the mechanism by which nerve growth factor (NGF) influences the LH secretory pathway in camelids, a series of experiments were done to determine the involvement of the hypothalamus (Experiment 1), the role of GnRH neurons (Experiment 2), and the effect of progesterone (Experiment 3) on the NGF-induced LH surge and ovulation in llamas. In Experiment 1, the declining phase of the NGF-induced LH surge was used to determine if the decline is a result of pituitary depletion or hypothalamic unresponsiveness. Female llamas were treated with NGF and, 7 h later, assigned to three groups and given a second dose of NGF (n = 5), a dose of GnRH (n = 5), or saline (n = 6). The LH response was attenuated after the second dose of NGF vs GnRH. In Experiment 2, Fos expression (marker of neuronal activation) in GnRH neurons was examined in the hypothalamus of llamas after NGF or saline treatment (n = 3 per group). Despite an LH surge in the NGF group but not in the saline group, no differences were detected between groups in Fos/GnRH co-expression. In Experiment 3, llamas in low-, medium-, and high-plasma progesterone groups (n = 4 per group) were treated with NGF. The NGF-induced LH surge did not differ among treatment groups. Results from the present study show that the induction of a preovulatory LH surge by NGF may be controlled by a novel pathway involving GnRH neuro-terminals downstream of the hypothalamus and is independent of progesterone influence.

Free access

Selena U Park, Leann Walsh, and Karen M Berkowitz

Ovarian aging in women correlates with the progressive loss of both the number and quality of oocytes. When these processes occur early or are accelerated, their clinical correlates are diminished ovarian reserve and/or premature ovarian insufficiency. Both these conditions have important consequences for the reproductive and general health of women, including infertility. Although there are many contributing factors, the molecular mechanisms underlying many of the processes associated with ovarian aging have not been fully elucidated. In this review, we highlight some of the most critical factors that impact oocyte quantity and quality with advancing age. We discuss chromosomal factors including cohesion deterioration and mis-segregation, errors in meiotic recombination, and decreased stringency of the spindle assembly checkpoint. DNA damage, telomere changes, reactive oxygen species and mitochondrial dysfunction as they relate to ovarian aging, and well-known gene mutations associated with primary ovarian insufficiency and diminished ovarian reserve are also discussed. Additionally, studies investigating recently acknowledged cytoplasmic factors associated with ovarian aging including protein metabolic dysregulation and microenvironmental alterations in the ovary are presented. We use both mouse and human studies to support the roles these factors play in physiologic and expedited ovarian aging, and we propose directions for future studies. A better understanding of the molecular basis of ovarian aging will ultimately lead to diagnostic and therapeutic advancements that would provide women with information to make earlier choices about their reproductive health.

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Liyuan Cui, Feng Xu, Songcun Wang, Zhuxuan Jiang, Lu Liu, Yan Ding, Xiaoli Sun, and Meirong Du

Deficient decidualization of endometrial stromal cells (ESCs) can cause adverse pregnancy outcomes including miscarriage, intrauterine growth restriction, and pre-eclampsia. Decidualization is regulated by multiple factors such as hormones and circadian genes. Melatonin, a circadian-controlled hormone, is reported to be important for various reproductive processes, including oocyte maturation and placenta development. Its receptor, MT1, is considered to be related to intrauterine growth restriction and pre-eclampsia. However, the role of melatonin-MT1 signal in decidualization remains unknown. Here, we reported that decidual stromal cells from miscarriages displayed deficient decidualization with decreased MT1 expression. The expression level of MT1 is gradually increased with the process of decidualization induction in vitro. MT1 knockdown suppressed the decidualization level, while the overexpression of MT1 promoted the decidualization process. Moreover, changing MT1 level could regulate the expression of decidualization-related transcription factor FOXO1. Melatonin promoted decidualization and reversed the decidualization deficiency due to MT1 knockdown. Using in vitro and in vivo experiments, we further identified that lipopolysaccharide (LPS) could induce inflammation and decidualization resistance with downregulated MT1 expression, and melatonin could reverse the inflammation and decidualization resistance induced by LPS. These results suggested that the melatonin-MT1 signal might be essential for decidualization and might provide a novel therapeutic target for decidualization deficiency-associated pregnancy complications.

Open access

Coleman H Young, Bryce Snow, Stanley B DeVore, Adithya Mohandass, Venkatesh V Nemmara, Paul R Thompson, Baskaran Thyagarajan, Amy M Navratil, and Brian D Cherrington

Peptidylarginine deiminases (PAD) enzymes were initially characterized in uteri, but since then little research has examined their function in this tissue. PADs post-translationally convert arginine residues in target proteins to citrulline and are highly expressed in ovine caruncle epithelia and ovine uterine luminal epithelial (OLE)-derived cell line. Progesterone (P4) not only maintains the uterine epithelia but also regulates the expression of endometrial genes that code for proteins that comprise the histotroph and are critical during early pregnancy. Given this, we tested whether P4 stimulates PAD-catalyzed histone citrullination to epigenetically regulate expression of the histotroph gene insulin-like growth factor binding protein 1 (IGFBP1) in OLE cells. 100 nM P4 significantly increases IGFBP1 mRNA expression; however, this increase is attenuated by pre-treating OLE cells with 100 nM progesterone receptor antagonist RU486 or 2 µM of a pan-PAD inhibitor. P4 treatment of OLE cells also stimulates citrullination of histone H3 arginine residues 2, 8, and 17 leading to enrichment of the ovine IGFBP1 gene promoter. Since PAD2 nuclear translocation and catalytic activity require calcium, we next investigated whether P4 triggers calcium influx in OLE cells. OLE cells were pre-treated with 10 nM nicardipine, an L-type calcium channel blocker, followed by stimulation with P4. Using fura2-AM imaging, we found that P4 initiates a rapid calcium influx through L-type calcium channels in OLE cells. Furthermore, this influx is necessary for PAD2 nuclear translocation and resulting citrullination of histone H3 arginine residues 2, 8, and 17. Our work suggests that P4 stimulates rapid calcium influx through L-type calcium channels initiating PAD-catalyzed histone citrullination and an increase in IGFBP1 expression.

Free access

Gregory W Kirschen, Abdelrahman AlAshqar, Mariko Miyashita-Ishiwata, Lauren Reschke, Malak El Sabeh, and Mostafa A Borahay

Fibroids are benign tumors caused by the proliferation of myometrial smooth muscle cells in the uterus that can lead to symptoms such as abdominal pain, constipation, urinary retention, and infertility. While traditionally thought of as a disease process intrinsic to the uterus, accumulating evidence suggests that fibroid growth may be linked with the systemic vasculature system, although cell-intrinsic factors are certainly of principal importance in their inception. Fibroids are associated with essential hypertension and preeclampsia, as well as atherosclerosis, for reasons that are becoming increasingly elucidated. Factors such as the renin–angiotensin–aldosterone system, estrogen, and endothelial dysfunction all likely play a role in fibroid pathogenesis. In this review, we lay out a framework for reconceptualizing fibroids as a systemic vascular disorder, and discuss how pharmaceutical agents and other interventions targeting the vasculature may aid in the novel treatment of fibroids.

Free access

Andy Greenfield

The birth of Dolly the sheep in 1996 elicited a tsunami of commentaries, both in the popular media and academic journals, including responses to the prospect of human reproductive cloning. Much of the anxiety expressed over this imagined consequence of Dolly’s genesis revealed fundamental concerns about us losing our commitments to certain ethical goods, such as human dignity, or even ‘what it means to be human’. Over the last 25 years, the focus of much of the ethical debate over human biotechnology has slowly shifted towards other genetic technologies that aim to influence inheritance, such as mitochondrial replacement techniques (MRT) and heritable genome editing. Genome editing, in particular, is a technology with multiple fields of application, actual and potential, in research and innovation. This review suggests that many of the fundamental concerns about the possibility of human reproductive cloning that were precipitated by Dolly persist today in the arguments of those who oppose MRT and any use of heritable human genome editing (HHGE). Whilst it is not accepted here that an understanding of human nature and dignity alone can demonstrate the ethical unacceptability of such assisted reproductive technologies, there are themes of justice, which extend into our relationships with animals, that demand continued wide-ranging examination and public dialogue. While Dolly has cast a long shadow over such discussions, this review suggests that the general existential angst over human uses of biotechnology that she came to symbolise is neither compulsory nor a reliable guide for how to think about biotechnologies today.