Reproduction, Fertility and Development

The fibrinolytic system (plasminogen–plasmin system) is involved in the process of fertilisation, although its function is not fully clarified. This study showed how different components of the plasminogen–plasmin system act in mouse species. Specifically, tissue plasminogen activator (tPA) seems to be necessary for the success of in vitro fertilisation (IVF) but not in vivo. These findings suggest that the addition of exogenous tPA during IVF treatments could be useful under specific circumstances.

Paternal genetic alterations through male gamete (sperm) may influence the embryo quality and reproductive outcome. This study investigated the response to paternally transmitted DNA lesions on genetic integrity and metabolism (the chemical processes that occur within the cell in order to maintain life) in early mouse embryos. Observations from this study indicate that the genetic integrity and metabolic behaviour of the embryos are influenced by paternally transmitted DNA lesions.

The follicular environment is essential for the oocyte to acquire competence to develop into a high quality embryo. In this work, we identified metabolites such as glucose, pyruvate, cholesterol and estrogen, as well as metabolic and stress pathways, as important factors in achieving this ability. These data will contribute to identifying follicles that are prone to generating embryos with higher viability.

Oocyte development is a highly complex process. Lipid composition of oocytes derived from different follicles sizes and their relationship with follicular fluid molecules, embryo development and blastocyst lipid deposit were identified. We suggest that maintaining the exposure of the oocyte to the follicular microenvironment allows oocytes to proceed with events that are necessary to reach maturity and the positive impact of lipid accumulation for development may be seen as a necessary step to the forthcoming intense proliferative activity of the growing embryo.

If the DNA is damaged in oocytes, what can we do to save them? In this research, we found that co-culturing with certain concentrations of Roscovitine and TSA can help porcine oocytes recover from DNA damage and proceed to maturation and development. This can be used to improve the living capability of oocytes in vitro and to inspire more possibilities of combined treatment.

Cell type-specific RNA sequencing (RNA-Seq) of equine endometrial biopsies from Day 12 of pregnancy and the corresponding day of the oestrous cycle revealed distinct gene expression patterns in luminal epithelium, glandular epithelium and stromal areas, which was compared with RNA-Seq data obtained for whole biopsy samples.

This study showed the dynamics of 5mC and 5hmC in developing PGCs and the effects of Tet1 on the development of PGCs. Knockdown of Tet1 reduced the process of DNA demethylation and damaged PGC development. This study will shed important light on the mechanism by which Tet1 affects PGC global DNA demethylation and methylation state of Dazl.

Cryopreservation may reduce embryo developmental competence. The aim of this study was to evaluate the effect of supplementing in vitro culture media and/or vitrification solutions with resveratrol on embryo quality. The vitrification and warming process increased active mitochondria and mitochondrial superoxide production, but the addition of resveratrol, either to the IVC medium or to the vitrification solution, helped embryos to partially recover their initial ‘quieter’ state (i.e. lower oxidative metabolism).

Cumulus­–oocyte complex expansion is essential for ovulation and fertilisation. This study revealed that cumulus area is not altered in mice with oocyte-specific deletion of C1galt1 and Mgat1, despite a reduction in hyaluronan and other molecules associated with cumulus expansion. A minimum threshold may exist for supporting cumulus expansion. Oocyte-secreted factors may be affected by the deletions, causing altered cumulus composition.

Using stem cell technology, a group of surrogate males that produce donor sperm were created for the first time in the dromedary camel. This technology has the potential to disseminate a favoured genotype in species where artificial insemination is not feasible due to the lack of effective semen freezing protocols. The treatment of the surrogate male’s testis with a protein, DBA lectin, is critical for the success of this process.

Temperature fluctuations induce molecular and morphological changes in aquatic organisms. In this study, we analysed embryo development under conditions of thermal stress and showed that reduced embryo viability and increased larval malformations are probably related to modifications in the expression of caspase-3 during early development, even with an increase in heat shock protein 70 levels. Understanding the effects of thermal stress could establish critical temperature limits during development, improving the quality of fish farming.

The involvement of lipid metabolism during porcine oocyte maturation is poorly understood. The aim of this study was to assess the effect of media carbohydrate composition on the modulation of lipid metabolism. The results revealed that stimulation of fatty acid oxidation was only beneficial when levels of carbohydrates were deficient. The findings will inform future media refinements to improve the IVM of porcine oocytes.

Mitochondria are vital for generating the energy an early embryo requires. In horse embryos, the number of mitochondria only increases when the embryo starts to expand and undergo cell differentiation; surprisingly, a low mitochondrial number before this time is not associated with embryo death. Understanding exactly when, and in which cells, mitochondrial replication starts may yield novel markers for a ‘healthy’ embryo.

The expression of glycoepitopes may be involved in the regulation of maternal immunity preventing rejection of spermatozoa. Seminal plasma separated by polyacrylamide gel electrophoresis with sodium dodecyl sulphate were probed with lectins specific to fucose and sialic acid. Differential expression of α2,3-linked sialic acid was found in 86% of analysed bands, contrary to the observed differences for other glycoepitopes. Mass spectrometry analysis focussed on the identification of proteins carrying glycans with immunomodulatory epitopes.

Mimicry, a phenomenon to date studied only in the context of autoimmune diseases, has been proposed to be a reason for immune infertility as well, owing to the similarity of proteins in bacteria and spermatozoa. The present study successfully validated this hypothesis by isolating the bacterial counterpart of a sperm protein and employing it for the treatment of infertility induced by sperm-impairing bacteria, thereby opening many therapeutic avenues.

Ensuring the pregnancy status of a sow as early as possible after breeding has become a top priority for profitable pig production. Comprehensive proteome profiling of sow serum during early pregnancy stages revealed several differentially expressed proteins including some significant pregnancy-related proteins. They could serve as potential biomarkers for pregnancy diagnosis as early as Day 12 after breeding, which would facilitate more-economic pig production.

3-NPA induces granulosa cell apoptosis, follicle atresia and MOFs in the ovaries of female mice, possibly acting through PARP-1 signalling. The aim of this research was to investigate the effects of 3-NPA on ovarian follicular development using both in vivo and in vitro models. These findings will be helpful in investigating the mechanisms controlling follicular development and atresia in mammals.

Steroid hormone synthesis is one function of granulosa cells and plays an important role in the maturation and function of reproductive organs. In this study we found that Notch signalling affected progesterone and oestradiol secretion by granulosa cells via regulation of interleukin-6 expression. This finding adds to our understanding of the diverse functions of Notch signalling in the mammalian ovary.

In mammals, oocyte quality is particularly important to improve reproductive capacity. In this study, baicalin, a traditional Chinese medicine monomer for treating infertility, was used during IVM of pig oocytes. Baicalin improved the IVM of pig oocytes and subsequent preimplantation embryo development by inhibiting apoptosis.

Male germ cell development requires testis-specific transcripts derived from the use of alternative promoters and transcription factors, and alternative splicing. We discovered that sperm-associated antigen 16S (SPAG16S) and Elongin B, a transcription elongation factor, form a complex localised in nuclear speckles, structures enriched in pre-mRNA splicing factors. This study discloses new players in the generation of germ cell-specific transcripts critical for spermatogenesis.

Peripubertal male and female rats maternally exposed to fluoxetine (FLX) were evaluated. The endpoints evaluated were: date of puberty onset, plasma testosterone and oestrogen concentrations before and after puberty onset and corticosterone concentration before and after adrenocorticotrophin stimulus. None of the endpoints were affected by FLX exposure. The results of this study suggest a lack of effect of FLX on steroid-related parameters.

The Hps1 and Ap3b1 genes encode proteins important to vesicle trafficking, but the roles they played in male reproduction were still unclear. Our results indicate that the Hps1 and Ap3b1 genes play distinct roles in reproductive organ development and spermatogenesis. This study advances our knowledge of protein trafficking on postnatal germ cell development and male fertility regulation.

Embryo implantation is a highly synchronised process and a precisely coordinated step during the establishment of pregnancy. Twist2 is found to be involved with embryo implantation and suppression of Twist2 could suppress embryo implantation by regulating EMT. These findings provide clues for understanding the complicated process of embryo implantation and the potential role of Twist2 during embryo implantation.

Summer heat stress compromises the function of female gametes, reducing the oocyte’s ability to be fertilised and to become an embryo. This study demonstrated the beneficial effect of the ovarian follicular fluid microenvironment in heat-shocked oocytes. Maturation medium supplementation with follicular fluid exosomes prevents heat stress damage in oocytes and can be a key to oocyte protection. 

CIRBP is reduced by scrotal hyperthermia, but there is no direct evidence clarifying the relationship between CIRBP and spermatogenesis. This study investigated the effects of the CIRBP on spermatocytes and found that CIRBP protected GC2-spd cells against apoptosis induced by heat stress. These findings suggest that CIRBP exerts a protective effect against spermatogenic injury caused by heat stress.

We first report that IQCD is an acrosome-associated gene that is localised in mature spermatozoa and the acrosome area of round and elongating spermatids within seminiferous tubules during the late stage of spermiogenesis. Most importantly, as a Munc13-interacting protein, IQCD plays a role in fertilisation and the acrosome reaction.

Sperm banking and artificial insemination could benefit conservation of the African wild dog, an endangered species with a dominance hierarchy where subordinates usually do not breed. We investigated the effect of social rank on male reproductive parameters and found no difference in sperm quality between dominant and subordinate males. Thus, reproductive suppression of subordinate males appears to be behaviourally mediated, making males of all social ranks suitable candidates for sperm banking.

The use of somatic cell nuclear transfer (SCNT) in equines may result in embryo bisection and twinning, which often lead to abnormal embryo development. A comparative analysis focusing on the central nervous system at 40 and 60 days gestation was performed. Although one fetus, at each age, was smaller in size, there were no macro- or microstructural differences between the twin fetuses, indicating that SCNT does not affect fetal differentiation.

How do men develop a uterus and what are the consequences? Learn about persistent Müllerian duct syndrome, a rare condition caused by disruption of the genetic pathway spearheaded by anti-Müllerian hormone (AMH). AMH suppresses internal female primordia, whereas testosterone, the other testicular product, builds the visible attributes of masculinity.

FOXD1 is an important member of the FOX family required for reproduction and development. We identified the male-biased expression of chicken FOXD1 and its location in the testicular Sertoli cell. Furthermore, FOXD1 affects the expression of AMH, SOX9, AR and RIα. These results provide important evidence for the role of FOXD1 during chicken testis development and for reproductive function.

At birth, the tammar wallaby (Macropus eugenii) neonate is essentially an exteriorised fetus. Therefore, during the 300–350 day lactation cycle, the tammar mother progressively alters milk composition, volume and individual milk constituents to provide appropriate nutrients for the pouch young. This review examines the correlation between changes in maternal milk and developmental milestones in the young, and explores the role of selected milk components.

The lncRNA Xist is crucial for early development of cloned embryos. However, little is known about Xist in cloned goats. In the present study we investigated the methylation status and expression patterns of Xist in SCNT 8-cell embryos, and well as in ear, lung, and brain tissues of female deceased cloned goats. We found highly methylated Xist in SCNT-generated 8-cell embryos and 3-day-old female deceased cloned goats. The data presented here suggest that highly methylated Xist in SCNT embryos was retained in female deceased cloned goats.

Reproductive biology is core to food supply, offspring developmental trajectories and health throughout life. This review of the 2018 Annual Meeting of the Society for Reproductive Biology summarises the key themes of the conference. Topics include gamete development, pregnancy, the effects of lifestyle on fertility and assisted reproduction.

Atrazine is a widely used herbicide in Australian agriculture and is a common contaminant in drinking water. We found that low concentrations of atrazine in the drinking water had significant effects on the reproductive and metabolic systems of mice. These data have implications for metabolic disorders and infertility in humans and indicate that a reassessment is needed for the levels of atrazine deemed safe in Australian drinking water.

Sequencing of marsupial genomes is helping us understand the evolution of features unique to marsupials. However, the DNA sequence is only one part of the dynamic structures it is packaged into: chromosomes. We need to consider how changes in chromosome packaging and how different chromosomes interact in a cell to fully understand the evolution of marsupial-specific features.

For patients with non-obstructive infertility, identifying possible spermatogenesis is important to realise parenthood. The testicular lamina propria is associated with spermatogenesis, and we found that Raman spectroscopy could non-invasively predict spermatogenesis by analysing the tubular lamina propria. The portable Raman system coupled with a fibre optic cable has the potential to be used with microdissection testicular sperm extraction during surgery to select tubules with the potential to develop spermatogenesis.

Cryopreservation is the process of cooling and storing living cells at very low temperatures to maintain their viability after warming. Vitrification is a popular way to freeze ‘ice-free’ human oocytes and embryos. This review discusses how vitrification is being optimised and standardised for in vitro-derived cattle embryos of defined quality as a useful tool for bovine IVF in commercial settings.

Not surprisingly, the number of oocytes is correlated with litter size, but the effects of mitochondrial (mt) DNA polymorphisms on porcine oocyte numbers remain unclear. In this study, mtDNA polymorphic sites, haplotypes and haplogroups were significantly associated with the number of porcine oocytes. Particular mtDNA haplotypes in pigs can be used as potential molecular markers for selection based on oocyte quantity and litter size.

In addition to diabetes, the clinical use of metformin in different pathologies is growing, and late-phase clinical trials of metformin in cancer therapy are underway. This study investigates the effects of metformin on human spermatozoa, and demonstrates undesirable effects, namely inhibition of sperm motility and essential sperm signalling pathways. This study is relevant to human reproduction, particularly for the fertility of patients who may be treated with metformin in the future.

Ovaries secrete anti-Müllerian hormone (AMH), which stimulates gonadotrophin secretion from gonadotrophs in bovines. This study revealed that gonadotrophs themselves express AMH. The AMH expression levels in anterior pituitaries (APs) were not affected by oestrous phase. The APs of old Holsteins exhibited lower AMH mRNA levels but higher AMH protein levels than those in young Japanese Black APs.

DEAD-box helicase 4 (DDX4; also known as vasa) is essential for the proper formation and maintenance of germ cells. After knocking down DDX4expression using retroviral vectors that encoded DDX4-targeting microRNAs, the number of primordial germ cells was decreased in male and female gonads of DDX4-knockdown chicken embryos. This indicates that DDX4 is essential to maintain a normal level of these cells in chicken embryos of both sexes.

Epididymal spermatozoa of the Chinese soft-shelled turtle possess usually large cytoplasmic droplets with several lipid droplets (LDs), which serve as an important energy source. During long-term sperm storage in the epididymis, LDs were degraded by lipophagy to sustain sperm longevity. Understanding the mechanism underlying sperm storage would provide insights into the reproductive strategy of the Chinese soft-shelled turtle and contribute to further studies on sperm conservation in vitro.

Although hibernation is an integral part of the life history of species living in seasonal environments, little is known about how hibernation affects reproductive success in amphibians. Our study shows that sperm output (quality and quantity) was not affected by hibernation lengths in the endangered Wyoming toad. These unexpected findings illustrate the potential of temperate amphibians to adapt to varying environmental conditions during winter months.

Optimum luteal function is essential for sound reproductive health in animals. In the present study, regulation of luteal function by thrombospondins and insulin was demonstrated in water buffalo and it was observed that thrombospondins impaired progesterone production by decreasing the viability of luteal cells, whereas insulin reversed the findings. This observation will help in controlling the life span of the corpus luteum and its function.

Seasonal breeders have distinct reproductive strategies, which include synchronised cycles of active and inactive epididymal function between the breeding and non-breeding seasons. The expression of pituitary-derived hormone receptors was positively correlated with morphological and histological changes in the epididymis of the wild ground squirrel. Pituitary-derived hormones may regulate the epididymal functional changes required to adapt to seasonal environmental changes.

We report two novel and unique phenotypes of MRL/MpJ mice in the female reproductive function. Superovulation treatment resulted in the production of significantly more oocytes with lower quality, and the faster luteinisation of ovulated follicles in MRL/MpJ than C57BL/6 mice. Our results provide novel insights into the effects of artificial ovulation on oocytes and ovaries in mice.

Haemoglobin is an important protein commonly found in red blood cells. In addition to carrying oxygen around the body, haemoglobin has the capacity to act as an antioxidant. We discovered surprisingly high amounts of haemoglobin in embryos grown in mice compared with those grown in the laboratory, which had much lower haemoglobin concentrations. Haemoglobin may play an important role in regulating oxygen during early embryo development and the absence of this protein may affect the health of embryos grown in the laboratory.

Marilyn Renfree was recognised as ‘a giant of marsupial embryology’; the author had spent her working life studying genes and chromosomes. Marilyn and Jenny teamed up out of mutual respect to form, with Des Cooper, the ARC Centre of Excellence in Kangaroo Genomics. This is the story of how their collaboration came to be, and what it has produced for our knowledge of some of the world’s most remarkable animals.

This study investigates the interspecific diversity in relative testes mass (RTM) and sperm morphology across the Philippine chrotomyine rodents. Major interspecific differences were found with coevolution being evident between RTM, sperm head shape and sperm tail length. The findings suggest differences in intensity of intermale sperm competition and hence breeding system across the species.

Platelet-activating factor (PAF) is a well-known growth factor, modulating various physiological processes, including reproduction. For many years, PAF was believed to reside solely at the plasma membrane. Here, we describe for the first time its nuclear origin in oocytes and embryos of cattle, mice and humans. This distinct location hints towards unique subcellular functions, left to be characterised.

Sperm macrocephaly syndrome (SMS), characterised by spermatozoa with enlarged heads and multiple tails, has not been described in birds. In the ostrich, affected spermatozoa are diploid, swim slower but straighter and the multiple tails are collectively bound within the cell membrane. SMS can occur in birds and may adversely affect breeding programs, particularly for endangered species.

The testes of most mammals need to be cooler than body temperature; increased temperatures cause formation of abnormal spermatozoa and poor fertility. When ram testes were warmed, there was increased blood flow and adequate oxygen. These results challenge a long-standing belief that testicular warming causes inadequate oxygen and may enable novel treatments to protect spermatozoa from the negative effects of increased testicular temperature.

The reproductive tract of live-bearing mammals undergoes vast remodelling to accommodate the developing embryo. The aim of this study was to determine the effect of the reproductive hormones progesterone and 17β-oestradiol on the reproductive tract of the marsupial Sminthopsis crassicaudata. We concluded that the remodelling of the uterine epithelium is regulated by the same hormonal mechanisms among mammalian species.

Exposure to high levels of oestradiol that produces local accumulation of active oestrogen metabolites can affect normal implantation. Herein the role of 2-methoxyoestradiol on the anti-implantation effect of oestradiol in the mouse was investigated. We found that oestradiol impairs embryo implantation through its conversion to 2-methoxyoestradiol and subsequent increase of F-spondin in the mouse uterus. These findings highlight the role of 2-methoxyoestradiol in embryo implantation failures under hyperoestrogenic conditions.

In sheep, the association between temperament associated with two single nucleotide polymorphism (SNP) genotypes and sheep reproduction has not yet been studied. This study investigated the association between steroid 17-alpha-hydroxylase/17,20 lyase (CYP17) SNP628 and dopamine receptor D2 (DRD2) SNP939 genotypes and concluded that sheep with the DRD2 SNP939 T/T genotype combined with the CYP17 SNP628 G/G genotype had better reproductive performance and maternal behaviour. The findings may be beneficial for sheep genetics and breeding.

In all, 3163 microRNAs (miRNAs) were expressed and detected in mouse blastocysts and outgrowth embryos. Of these, the expression of10 miRNA candidates (let-7b, miR-23a, miR-27a, miR-92a, miR-183, miR-200c, miR-291a, miR-425, miR-429 and miR-652) was identified as significantly different in outgrowth embryos. These differentially expressed miRNAs could be involved in embryo attachment and the implantation process between the embryo proper and the maternal endometrium.

Approximately 45% of azoospermia patients are able to father their own offspring via microsurgery, but there is no reliable test to predict testicular spermatozoa existence before the surgery. We detected and compared specific molecules called microRNAs in the testis from patients whom spermatozoa were successfully versus unsuccessfully extracted, and found that there were significant differences between the two groups. The findings suggest the possibility of using differentially expressed microRNAs in the testis of the patients as a non-invasive technique for preoperative diagnoses.

Polyamines are small, ubiquitous molecules essential for cell proliferation and growth that are involved in multiple aspects of reproduction. Recent results have highlighted the importance of polyamines in coordinating the molecular signalling that occurs between the embryo and uterus to control the events surrounding implantation. Identification of the essential role for polyamines during this critical stage is providing new insights into the requirements for the establishment of a successful pregnancy.

Transcription factors are essential mediators of ovulation and luteinisation. The present study demonstrates that there are significantly increase in levels of the transcription factor high mobility group AT-hook 1 (HMGA1) after administration of human chorionic gonadotropin to rats. Induction of Hmga1 mRNA is mediated through both the protein kinase (PK) A and PKC signalling pathways by activation of the epidermal growth factor receptor and requires the synthesis of a new protein(s). Temporal stimulation of HMGA1 may be important for theca and granulosa cell differentiation into luteal cells.

Transcript abundance of immunoglobulin isotypes and relevant transporters, FcRN and pIgR, were quantified within the opossum mammaries throughout lactation. Results support the presence of a dynamic lactation scheme in the opossum mammary that correlates with neonatal immune development.

Tasmanian devils are threatened by devil facial tumour disease, a transmissible cancer with a high fatality rate. In response, the Save the Tasmanian Devil Program established a breeding program as an ‘insurance population’ that has been integral to the conservation of the species. Studying the genetic diversity of the species in the wild and in captivity has enabled us to improve the reproductive success of devils.

Accurate dissection of blastocysts into inner cell mass and trophectoderm is critical for numerous experiments in embryology and developmental biology. We show that serum from α-1,3-galactosyltransferase deficient pigs can be used as an antibody source for embryo immunosurgery in several species, which allows standardised experimental approaches and facilitates comparative developmental studies, e.g. in lineage-specific transcriptome profiling and chimeric aggregation studies.