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A refined culture system of oocytes from early antral follicles promotes oocyte maturation and embryo development in cattle

Rodrigo Garcia Barros, Valentina Lodde, Federica Franciosi, and Alberto Maria Luciano

In brief

The proposed culture system improves the current state of in vitro culture of growing oocytes in the bovine species and allows access to the untapped gamete reserve, thus improving reproductive efficiency.

Abstract

The present study aimed to improve the in vitro culture of bovine oocytes collected from early antral follicles (EAFs) to support the progressive acquisition of meiotic and developmental competence. The rationale that drove the development of such a culture system was to maintain as much as possible the physiological conditions that support the oocyte growth and differentiation in vivo. To this extent, oocytes were cultured for 5 days, which parallels the transition from early to medium antral follicles (MAFs) in the bovine, and supports promoting a 3D-like structure were provided. Additionally, the main hormones (follicle-stimulating hormone, estradiol, progesterone, and testosterone) were added in concentrations similar to the ones previously observed in bovine EAFs. The meiotic arrest was imposed using cilostamide. The cultured cumulus–oocyte complexes (COCs) reached a mean diameter of 113.4 ± 0.75 µm and showed a progressive condensation of the chromatin enclosed in the germinal vesicle (GV), together with a gradual decrease in the global transcriptional activity, measured by 5-ethynyl uridine incorporation. The described morpho-functional changes were accompanied by an increased ability to mature and develop to the blastocyst stage in vitro, although not matching the rates obtained by MAF-retrieved oocytes. The described system improves the current state of in vitro culture of growing oocytes in the bovine species, and it can be used to increase the number of gametes usable for in vitro embryo production in animals of high genetic merit or with specific desirable traits.

DOI:
https://doi.org/10.1530/REP-22-0277
Volume 165: Issue 2,
Pages:
221–233 (13 total)
Restricted access

Roles of the cumulus–oocyte transzonal network and the Fragile X protein family in oocyte competence

Elolo Karen Nenonene, Mallorie Trottier-Lavoie, Mathilde Marchais, Alexandre Bastien, Isabelle Gilbert, Angus D Macaulay, Edouard W Khandjian, Alberto Maria Luciano, Valentina Lodde, Robert S Viger, and Claude Robert

In brief

RNA granules travel through the cumulus cell network of transzonal projections which is associated with oocyte developmental competence, and RNA packaging involves RNA-binding proteins of the Fragile X protein family.

Abstract

The determinants of oocyte developmental competence have puzzled scientists for decades. It is known that follicular conditions can nurture the production of a high-quality oocyte, but the underlying mechanisms remain unknown. Somatic cumulus cells most proximal to the oocyte are known to have cellular extensions that reach across the zona pellucida and contact with the oocyte plasma membrane. Herein, it was found that transzonal projections (TZPs) network quality is associated with developmental competence. Knowing that ribonucleoparticles are abundant within TZPs, the distribution of RNA-binding proteins was studied. The Fragile X-related proteins (FXR1P and FXR2P) and two partnering protein families, namely cytoplasmic FMRP-interacting protein and nuclear FMRP-interacting protein, exhibited distinctive patterns consistent with roles in regulating mRNA packaging, transport, and translation. The expression of green fluorescent protein (GFP)–FMRP fusion protein in cumulus cells showed active granule formation and their transport and transfer through filipodia connecting with neighboring cells. Near the projections’ ends was found the cytoskeletal anchoring protein Filamin A and active protein synthesis sites. This study highlights key proteins involved in delivering mRNA to the oocyte. Thus, cumulus cells appear to indeed support the development of high-quality oocytes via the transzonal network.

DOI:
https://doi.org/10.1530/REP-22-0165
Volume 165: Issue 2,
Pages:
209–219 (11 total)
Free access

Sex, puberty, and the gut microbiome

Laura Sisk-Hackworth, Scott T Kelley, and Varykina G Thackray

In brief

Sex differences in the gut microbiome may impact multiple aspects of human health and disease. In this study, we review the evidence for microbial sex differences in puberty and adulthood and discuss potential mechanisms driving differentiation of the sex-specific gut microbiome.

Abstract

In humans, the gut microbiome is strongly implicated in numerous sex-specific physiological processes and diseases. Given this, it is important to understand how sex differentiation of the gut microbiome occurs and how these differences contribute to host health and disease. While it is commonly believed that the gut microbiome stabilizes after 3 years of age, our review of the literature found considerable evidence that the gut microbiome continues to mature during and after puberty in a sex-dependent manner. We also review the intriguing, though sparse, literature on potential mechanisms by which host sex may influence the gut microbiome, and vice versa, via sex steroids, bile acids, and the immune system. We conclude that the evidence for the existence of a sex-specific gut microbiome is strong but that there is a dearth of research on how host–microbe interactions lead to this differentiation. Finally, we discuss the types of future studies needed to understand the processes driving the maturation of sex-specific microbial communities and the interplay between gut microbiota, host sex, and human health.

DOI:
https://doi.org/10.1530/REP-22-0303
Volume 165: Issue 2,
Pages:
R61–R74
Restricted access

Suprachiasmatic nucleus and vagus nerve trigger preovulatory LH and ovulation

Elizabeth Vieyra, Julio C García, Hugo A Zarco, Rosa Linares, Gabriela Rosas, Deyra A Ramírez, Andrea Chaparro, Julieta A Espinoza, Roberto Domínguez, and Leticia Morales-Ledesma

In brief

In the proestrus day, the neural and endocrine signals modulate ovarian function. This study shows vagus nerve plays a role in the multisynaptic pathways of communication between the suprachiasmatic nucleus and the ovaries where such neural information determines ovulation.

Abstract

The suprachiasmatic nucleus (SCN) regulates the activity of several peripheral organs through a parasympathetic–sympathetic pathway. Previously, we demonstrated that atropine (ATR) microinjection in the right SCN of rats during proestrus blocks ovulation. In the present study, we analysed whether the vagus nerve is one of the neural pathways by which the SCN regulates ovulation. For this, CIIZ-V strain cyclic rats on the day of proestrus were microinjected with a saline solution (vehicle) or ATR in the right or left SCN, which was followed by ventral laparotomy or ipsilateral vagotomy to the microinjection side. Some animal groups were sacrificed (i) on the same day of the surgery to measure oestradiol, progesterone and luteinizing hormone (LH) levels or (ii) at 24 h after surgery to evaluate ovulation. The left vagotomy in rats microinjected with ATR in the left SCN did not modify ovulation. In rats with ATR microinjection in the right SCN, the right vagotomy increased the levels of steroids and LH on the proestrus and ovulatory response. The present results suggest that the right vagus nerve plays a role in the multisynaptic pathways of communication between the SCN and the ovaries and indicate that such neural information participates in the regulation of the oestradiol and progesterone surge, which triggers the preovulatory peak of LH and determines ovulation.

DOI:
https://doi.org/10.1530/REP-22-0119
Volume 165: Issue 2,
Pages:
147–157 (11 total)
Restricted access

The transcription factor TCFL5 responds to A-MYB to elaborate the male meiotic program in mice

Katharine Cecchini, Adriano Biasini, Tianxiong Yu, Martin Säflund, Haiwei Mou, Amena Arif, Atiyeh Eghbali, Cansu Colpan, Ildar Gainetdinov, Dirk G de Rooij, Zhiping Weng, Phillip D Zamore, and Deniz M Özata

In brief

The testis-specific transcription factor, TCFL5, expressed in pachytene spermatocytes regulates the meiotic gene expression program in collaboration with the transcription factor A-MYB.

Abstract

In male mice, the transcription factors STRA8 and MEISON initiate meiosis I. We report that STRA8/MEISON activates the transcription factors A-MYB and TCFL5, which together reprogram gene expression after spermatogonia enter into meiosis. TCFL5 promotes the transcription of genes required for meiosis, mRNA turnover, miR-34/449 production, meiotic exit, and spermiogenesis. This transcriptional architecture is conserved in rhesus macaque, suggesting TCFL5 plays a central role in meiosis and spermiogenesis in placental mammals. Tcfl5em1/em1 mutants are sterile, and spermatogenesis arrests at the mid- or late-pachytene stage of meiosis. Moreover, Tcfl5+/em1 mutants produce fewer motile sperm.

DOI:
https://doi.org/10.1530/REP-22-0355
Volume 165: Issue 2,
Pages:
183–196 (14 total)
Free access

Acknowledgement to reviewers

DOI:
https://doi.org/10.1530/REP-165-A1
Volume 165: Issue 1,
Pages:
A1–A2
Restricted access

Alternating mealtimes during pregnancy and weaning triggers behavioral changes in adult offspring

Mi-Hee Kim, Jihyun Park, Dong-Hee Han, Jong-Yun Noh, Eun-Sang Ji, Sung-Ho Lee, Chang-Ju Kim, and Sehyung Cho

In brief

Mealtime changes in pregnant mice revealed impaired neurobehavioral development in mouse offspring. This study is the basis for investigating diseases associated with neurobehavioral development of adult offspring of pregnant shift-working women.

Abstract

Most organisms on Earth have a biological clock, and their physiological processes are regulated by a 1-day cycle. In modern society, several factors can disturb these biological clocks in humans; in particular, individuals working in shifts are exposed to stark environmental changes that interfere with their biological clock. They have a high risk of various diseases. However, there are scarce experimental approaches to address the reproductive and health consequences of shift work in the offspring of exposed individuals. In this study, considering the fact that shift workers usually have their meals during their adjusted working time, we aimed to examine the effects of a 12-h shift with usual mealtime as a plausible night work model on the neurobehavioral development of adult mouse offspring. In these offspring, early exposure to this mealtime shift differentially affected circadian rhythmic variables and total locomotor activity depending on the timing and duration of restrictive feeding. Moreover, neurobehavioral alterations such as declined short-term memory and depressive-like behavior were observed in adulthood. These results have implications for the health concerns of shift-working women and their children.

DOI:
https://doi.org/10.1530/REP-22-0164
Volume 165: Issue 1,
Pages:
135–146 (12 total)
Open access

Chromatin remodelers HELLS, WDHD1 and BAZ1A are dynamically expressed during mouse spermatogenesis

Ram Prakash Yadav, Sini Leskinen, Lin Ma, Juho-Antti Mäkelä, and Noora Kotaja

In brief

Proper regulation of heterochromatin is critical for spermatogenesis. This study reveals the dynamic localization patterns of distinct chromatin regulators during spermatogenesis and disrupted sex chromatin status in spermatocytes in the absence of DICER.

Abstract

Heterochromatin is dynamically formed and organized in differentiating male germ cells, and its proper regulation is a prerequisite for normal spermatogenesis. While heterochromatin is generally transcriptionally silent, we have previously shown that major satellite repeat (MSR) DNA in the pericentric heterochromatin (PCH) is transcribed during spermatogenesis. We have also shown that DICER associates with PCH and is involved in the regulation of MSR-derived transcripts. To shed light on the heterochromatin regulation in the male germline, we studied the expression, localization and heterochromatin association of selected testis-enriched chromatin regulators in the mouse testis. Our results show that HELLS, WDHD1 and BAZ1A are dynamically expressed during spermatogenesis. They display limited overlap in expression, suggesting involvement in distinct heterochromatin-associated processes at different steps of differentiation. We also show that HELLS and BAZ1A interact with DICER and MSR chromatin. Interestingly, deletion of Dicer1 affects the sex chromosome heterochromatin status in late pachytene spermatocytes, as demonstrated by mislocalization of Polycomb protein family member SCML1 to the sex body. These data substantiate the importance of dynamic heterochromatin regulation during spermatogenesis and emphasize the key role of DICER in the maintenance of chromatin status in meiotic male germ cells.

DOI:
https://doi.org/10.1530/REP-22-0240
Volume 165: Issue 1,
Pages:
49–63 (15 total)
Restricted access

EGF promotes human trophoblast cell invasion by downregulating CTGF expression via PI3K/AKT signaling

Jung-Chien Cheng, Yibo Gao, Jiaye Chen, Qingxue Meng, and Lanlan Fang

In brief

Although the pro-invasive role of epidermal growth factor (EGF) has been reported in human trophoblast cells, the underlying mechanism remains largely unexplored. This work reveals that EGF-induced downregulation of connective tissue growth factor (CTGF) mediates the EGF-stimulated human trophoblast cell invasion.

Abstract

During the development of the placenta, trophoblast cell invasion must be carefully regulated. Although EGF has been shown to promote trophoblast cell invasion, the underlying mechanism remains largely undetermined. Our previous study using RNA-sequencing (RNA-seq) has identified that kisspeptin-1 is a downstream target of EGF in a human trophoblast cell line, HTR-8/SVneo, and mediates EGF-stimulated cell invasion. In the present study, after re-analysis of our previous RNA-seq data, we found that the CTGF was also downregulated in response to the EGF treatment. The inhibitory effects of EGF on CTGF mRNA and protein levels were confirmed in HTR-8/SVneo cells by reverse transcription quantitative real-time PCR and western blot, respectively. Treatment with EGF activated both PI3K/AKT and ERK1/2 signaling pathways. Using pharmacological inhibitors, our results showed that EGFR-mediated activation of PI3K/AKT signaling was required for the EGF-downregulated CTGF mRNA and protein levels. Matrigel-coated transwell invasion assays demonstrated that EGF treatment stimulated cell invasion. In addition, the invasiveness of HTR-8/SVneo cells was suppressed by treatment with recombinant human CTGF. By contrast, siRNA-mediated knockdown of CTGF increased cell invasion. Notably, the EGF-promoted HTR-8/SVneo cell invasion was attenuated by co-treatment with CTGF. This study provides important insights into the molecular mechanisms mediating EGF-stimulated human trophoblast cell invasion and increases the understanding of the biological functions of CTGF in the human placenta.

DOI:
https://doi.org/10.1530/REP-22-0247
Volume 165: Issue 1,
Pages:
113–122 (10 total)
Restricted access

Glucagon-like peptide-1 promotes Leydig cell regeneration from stem cells in rats

Xiaoheng Li, Lanlan Chen, Yiyan Wang, Huitao Li, Qiqi Zhu, and Ren-Shan Ge

In brief

Glucagon-like peptide-1 stimulates stem Leydig cell development. Glucagon-like peptide-1 stimulates stem Leydig cell differentiation without affecting its proliferation.

Abstract

The regulators of stem Leydig cell (SLC) development remain largely unknown. The effect of glucagon-like peptide-1 (GLP-1) on rat SLC proliferation and differentiation was investigated using a 3D tissue culture system and an ethane dimethane sulfonate (EDS)-treated in vivo LC regeneration model. RNA-seq analysis was performed to analyze pathways in which GLP-1 may be involved. GLP-1 (3 and 30 nmol/L) significantly increased medium testosterone abundances and upregulated the expression of Scarb1, Cyp11a1, and Hsd11b1. GLP-1 in vitro did not affect SLC proliferation by 5-Ethynyl-2’- deoxyuridine (EdU) incorporation assay. Intratesticular injection of GLP-1 (10 and 100 ng/testis) into the LC-depleted testis from day 14 to day 28 post-EDS significantly increased serum testosterone abundances and upregulated the expression of Cyp11a1, Hsd3b1, and Hsd11b1. It did not affect the number of HSD11B1+ and CYP11A1+ LCs. RNA-seq analysis revealed that GLP-1 upregulated several pathways, including cAMP-PKA-EPAC1 and MEK/ERK1/2. GLP-1 stimulates SLC differentiation without affecting its proliferation, showing its novel action and mechanism on rat SLC development.

DOI:
https://doi.org/10.1530/REP-22-0136
Volume 165: Issue 1,
Pages:
19–30 (12 total)