Expression of Transcripts in Marmoset Oocytes Retrieved during Follicle Isolation Without Gonadotropin Induction

Non-human primate: the new frontier model of female reproductive engineering

Reproductive engineering encompasses a range of advanced tissue engineering techniques aimed at addressing infertility that is non-curable with current assisted reproductive technology (ART). The use of animal models has been crucial for these advancements, with a notable preference for non-human primates (NHPs) given their genetic, anatomical, and physiological similarities to humans. Therefore, NHPs are invaluable for studying reproductive engineering. Thus, in reproductive studies, NHPs bridge the anatomical and physiological gaps between rodent models and humans. Their shared features with humans, such as menstrual cycles, placentation, and hormonal regulation, allow for more accurate modeling of reproductive physiology and pathology. These traits make NHPs indispensable in the exploration of reproductive engineering, including infertility treatments, genetic engineering, and uterine transplantation. Reproductive engineering is a transformative field that addresses infertility and enhances reproductive health. By leveraging the unique traits of NHPs, researchers can deepen their understanding of reproductive processes and refine ART techniques for human use. Advances in genetic engineering have enabled the creation of transgenic NHP models, which have been used to modify genes to investigate roles for various purposes, and the process, as mentioned earlier, is closely related to the ART technique, including fertility, embryogenesis, and pregnancy. Therefore, the relation to reproductive studies and the necessity of the NHP model are prerequisites for reproductive engineering. The engineering of NHPs is critically related to integrating ethical practices and exploring complementary methodologies. This review overviews the types of NHP frequently used and studies using NHP for reproductive engineering. These studies may suggest a broader way to use NHP for reproductive engineering.

Assessment of apoptosis and oxidative stress in cryopreserved ovary after grafting in fibrin-alginate scaffold with endothelial cells and melatonin in wistar rats

OBJECTIVE

Infertility is a significant public health concern affecting 10-15 % of couples. Young women undergoing gonadotoxic treatment are at higher risk of ovarian dysfunction and infertility. To mitigate this risk, ovarian tissue freezing and transplantation have been developed as a novel strategy. However, challenges such as follicular loss and dysfunction during the freezing process, and ovarian damage during transplantation, persist. This study aimed to investigate the potential of using appropriate antifreeze, antioxidant, wound healing, and biological hydrogels to reduce these injuries. Specifically, the effect of fibrin scaffold with endothelial cells and melatonin on apoptotic gene expression and antioxidants in cryopreserved ovaries after transplantation was examined.

METHODS

A total of 36 adult female wistar rats) 6-8-week-old and weighing from 200 to 220 g) were divided equally into six groups (n = 6): 1) control group (C), 2) transplanted ovarian tissue after vitrification and thawing process (Group 1), 3) transplanted vitrified/thawed ovarian tissue while encapsulated in Fib/Alg hydrogel (Group 2), 4) transplanted vitrified/thawed ovarian tissue while encapsulated in Fib/Alg hydrogel in addition with melatonin (Group 3), 5) transplanted vitrified/thawed ovarian tissue while encapsulated in Fib/Alg hydrogel in addition with endothelial cells (Group 4) and 6) transplanted vitrified/thawed ovarian tissue while encapsulated in Fib/Alg hydrogel in addition with melatonin endothelial cells (Group 5). The ovaries were auto-transplanted in the rats' lumbar region. After 14 days, the ovaries were removed. Antioxidant levels (SOD, GPx, MDA, and TAC) were evaluated using ELISA, and apoptotic gene expressions (Bax/Bcl2 and caspase 3) were analyzed by real-time RT-PCR to determine apoptosis.

RESULTS

In the transplanted frozen ovary group, Bax/Bcl2 and caspase 3 gene expression increased significantly (P < 0.05), while antioxidant levels (SOD, GPx, MDA, and TAC) decreased. The encapsulated frozen ovary group showed decreased gene expression and increased antioxidant levels. The ovary group encapsulated with fibrin scaffold, endothelial cells, and melatonin had the most significant decrease in gene expression and increase in antioxidant levels (P < 0.05).

CONCLUSION

Coordinated action of Fibrin-based scaffold with endothelial cells and melatonin could decrease apoptosis gene expression and increase antioxidant levels in cryopreserved ovaries after transplantation, providing valuable insights into preserving fertility in young women undergoing gonadotoxic treatment.

Transcriptomic Profiling of Reproductive Age Marmoset Monkey Ovaries

The decline in ovarian reserve and the aging of the ovaries is a significant concern for women, particularly in the context of delayed reproduction. However, there are ethical limitations and challenges associated with conducting long-term studies to understand and manipulate the mechanisms that regulate ovarian aging in human. The marmoset monkey offers several advantages as a reproductive model, including a shorter gestation period and similar reproductive physiology to that of human. Additionally, they have a relatively long lifespan compared to other mammals, making them suitable for long-term studies. In this study, we focused on analyzing the structural characteristics of the marmoset ovary and studying the mRNA expression of 244 genes associated with ovarian aging. We obtained ovaries from marmosets at three different reproductive stages: pre-pubertal (1.5 months), reproductive (82 months), and menopausal (106 months) ovaries. The structural analyses revealed the presence of numerous mitochondria and lipid droplets in the marmoset ovaries. Many of the genes expressed in the ovaries were involved in multicellular organism development and transcriptional regulation. Additionally, we identified the expression of protein-binding genes. Within the expressed genes, VEGFA and MMP9 were found to be critical for regulating ovarian reserve. An intriguing finding of the study was the strong correlation between genes associated with female infertility and genes related to fibrosis and wound healing. The authors suggest that this correlation might be a result of the repeated rupture and subsequent healing processes occurring in the ovary due to the menstrual cycle, potentially leading to the indirect onset of fibrosis. The expression profile of ovarian aging-related gene set in the marmoset monkey ovaries highlight the need for further studies to explore the relationship between fibrosis, wound healing, and ovarian aging.

Identification of Stem Cell-Like Cells in the Ovary

Understanding the function of stem cells and cellular microenvironments in in vitro oogenesis, including ovarian folliculogenesis, is crucial for reproductive biology. Because mammalian females cannot generate oocytes after birth, the number of oocyte decreases with the progression of reproductive age. Meanwhile, there is an emerging need for the neogenesis of female germ cells to treat the increasing infertility-related issues in cancer survivors. The concept of oocytes neogenesis came from the promising results of stem cells in reproductive medicine. The stem cells that generate oocytes are defined as stem cell-like cells in the ovary (OSCs). Several recent studies have focused on the origin, isolation, and characteristic of OSCs and the differentiation of OSCs into oocytes, ovarian follicles and granulosa cells. Hence, in this review, we focus on the experimental trends in OSC research and discuss the methods of OSC isolation. We further summarized the characteristics of OSCs and discuss the markers used to identify OSCs differentiated from various cell sources. We believe that this review will be beneficial for advancing the research and clinical applications of OSCs.

Synergistic Promoting Effects of X-Linked Inhibitor of Apoptosis Protein and Matrix on the In Vitro Follicular Maturation of Marmoset Follicles

BACKGROUND

In vitro follicular maturation (IVFM) of ovarian follicles is an emerging option for fertility preservation. Many paracrine factors and two-dimensional or three-dimensional (3D) environments have been used for optimization. However, since most studies were conducted using the murine model, the physiological differences between mice and humans limit the interpretation and adaptation of the results. Marmoset monkey is a non-human primate (NHPs) with more similar reproductive physiology to humans. In this study, we attempted to establish a 3D matrix (Matrtigel)-based IVFM condition for marmoset ovarian follicles in combination with anti-apoptotic factor, X-linked inhibitor of apoptosis protein (XIAP).

METHODS

Marmoset follicles were isolated as individual follicles and cultured in a single drop with the addition of 0, 10, and 100 μg/mL of XIAP molecules. Matured oocytes and granulosa cells from mature follicles were collected and analyzed. The average number of isolated follicles was less than 100, and primordial and antral follicles were abundant in the ovaries.

RESULTS

IVFM of marmoset follicles in 3D matrix conditions with XIAP increased the rates of survival and in vitro follicle development. Furthermore, oocytes from the 3D cultures were successfully fertilized and developed in vitro. The addition of XIAP increased the secretion of estradiol and aromatase. Furthermore, expression of granulosa-specific genes, such as bone morphogenetic protein 15, Oct4, and follicle-stimulating hormone receptor were upregulated in the in vitro-matured follicles than in normal, well-grown, and atretic follicles. Apoptosis-related B-cell lymphoma-2 was highly expressed in the atretic follicles than in the XIAP-treated follicles, and higher caspase-3 was localized in the XIAP-treated follicles.

CONCLUSION

In this study, we attempted to establish a 3D-matrix-based marmoset IVFM condition and demonstrated the synergistic effects of XIAP. The use of a 3D matrix may be applied as an optimal culture condition for marmoset ovarian follicles.

Transcriptome Analyses Identify Potential Key microRNAs and Their Target Genes Contributing to Ovarian Reserve

Female endocrinological symptoms, such as premature ovarian inefficiency (POI) are caused by diminished ovarian reserve and chemotherapy. The etiology of POI remains unknown, but this can lead to infertility. This has accelerated the search for master regulator genes or other molecules that contribute as enhancers or silencers. The impact of regulatory microRNAs (miRNAs) on POI has gained attention; however, their regulatory function in this condition is not well known. RNA sequencing was performed at four stages, 2-(2 W), 6-(6 W), 15-(15 W), and 20-(20 W) weeks, on ovarian tissue samples and 5058 differentially expressed genes (DEGs) were identified. Gene expression and enrichment were analyzed based on the gene ontology and KEGG databases, and their association with other proteins was assessed using the STRING database. Gene set enrichment analysis was performed to identify the key target genes. The DEGs were most highly enriched in 6 W and 15 W groups. Figla, GDF9, Nobox, and Pou51 were significantly in-creased at 2 W compared with levels at 6 W and 20 W, whereas the expression of Foxo1, Inha, and Taf4b was significantly de-creased at 20 W. Ccnd2 and Igf1 expression was maintained at similar levels in each stage. In total, 27 genes were upregulated and 26 genes interacted with miRNAs; moreover, stage-specific upregulated and downregulated interactions were demonstrated. Increased and decreased miRNAs were identified at each stage in the ovaries. The constitutively expressed genes, Ccnd2 and Igf1, were identified as the major targets of many miRNAs (p < 0.05), and Fshr and Foxo3 interacted with miRNAs, namely mmu-miR-670-3p and mmu-miR-153-3p. miR-26a-5p interacted with Piwil2, and its target genes were downregulated in the 20 W mouse ovary. In this study, we aimed to identify key miRNAs and their target genes encompassing the reproductive span of mouse ovaries using mRNA and miRNA sequencing. These results indicated that gene sets are regulated in the reproductive stage-specific manner via interaction with miRNAs. Furthermore, consistent expression of Ccnd2 and Igf1 is considered crucial for the ovarian reserve and is regulated by many interactive miRNAs.

Integrated analysis of miRNA-mRNA interaction in ovaries of Turpan Black Sheep during follicular and luteal phases

To investigate the regulatory mechanism of the follicular-luteal phase transition in Turpan black sheep (Ovis aries), the genome-wide expression patterns of microRNAs (miRNAs) and genes were investigated in ovaries of six sheep (3 years and single lamb with 3 consecutive births) during follicular and luteal phases of the oestrous cycle. Bioinformatic analysis was used to screen potential miRNAs and genes related to Turpan black sheep ovarian function. RT-qPCR was used to validate the sequencing results. In total, we identified 139 known and 71 novel miRNAs in the two phases with miRNA-seq, and a total of 19 miRNAs were significantly differentially expressed, of which 7 were up-regulated and 12 were down-regulated in the follicular phase compared with luteal phase. A total of 150 genes were significantly differentially expressed, including 63 up-regulated and 87 down-regulated in the follicular phase compared with the luteal phase by RNA-seq data analysis. Those DEGs were significantly enriched in 103 GO terms and several KEGG pathways, including metabolic pathway, ovarian steroidogenesis, steroid hormone biosynthesis and oestrogen signalling pathway. In addition, we created a miRNA-mRNA regulatory network to further elucidate the mechanism of follicular-luteal transition. Finally, we identified key miRNAs and genes including miR-143, miR-99a, miR-150, miR-27a, miR-125b, STAR, STAT1, which might play crucial roles in reproductive hormone biosynthesis and follicular development. The miRNA-mRNA interactive network clearly illustrates molecular basis involving in follicular-luteal transition.

A new possibility in fertility preservation: The artificial ovary

Conventional fertility preservation methods such as oocyte or embryo cryopreservation are currently insufficient to treat including those patients with prepubertal cancer and premature ovarian failure. Ovarian tissue cryopreservation presents as an alternative but has limitations with a potential risk of reintroducing malignant cells in patients who recover from cancer, those of chemotherapy prior to tissue cryopreservation. The so called "artificial ovary" aims to resolve this issue by transplanting isolated follicles with or without a biological scaffold. The artificial ovary may also offer an effective alternative option for those who cannot benefit from traditional assisted reproductive techniques such as in vitro fertilisation. To date, in animal studies and human trial, the artificial ovary restored endocrine function, achieved in vivo follicular development, and resulted in successful pregnancies. However, development of a technique for higher follicular recovery rate and a more optimised design of delivery scaffold, better transplantation techniques to prevent postsurgical ischemia, and consideration for genetic safety are required for safer and consistent human clinical applications. Ideas from different transplantation surgeries (e.g., entire ovary, ovarian cortex, and transplantation with tissue-engineered products) can be applied to enhance the efficacy of artificial ovarian transplantation. For the better application of artificial ovary, a deeper understanding of mechanical and biochemical properties of the ovary and folliculogenesis after cryopreservation, transplantation with or without scaffold, and development of sophisticated in vivo imaging techniques of transplanted artificial ovary need to precede its efficient clinical application.

Reference values of hematological and biochemical parameters in young-adult cynomolgus monkey (Macaca fascicularis) and rhesus monkey (Macaca mulatta) anesthetized with ketamine hydrochloride

Nonhuman primate models are valuable in biomedical research. However, reference data for clinical pathology parameters in cynomolgus and rhesus monkeys are limited. In the present study, we established hematologic and biochemical reference intervals for healthy cynomolgus and rhesus monkeys anesthetized with ketamine hydrochloride. A total of 142 cynomolgus monkeys (28 males and 114 females) and 42 rhesus monkeys (22 males and 20 females) were selected and analyzed in order to examine reference intervals of 20 hematological and 16 biochemical parameters. The effects of sex were also investigated. Reference intervals for hematological and biochemical parameters were separately established by species (cynomolgus and rhesus) and sex (male and female). No sex-related differences were determined in erythrocyte-related parameters for cynomolgus and rhesus monkey housed in indoor laboratory conditions. Alkaline phosphatase and gamma glutamyltransferase were significantly lower in females than males in both cynomolgus and rhesus monkeys aged 48–96 months. The reference values for hematological and biochemical parameters established herein might provide valuable information for researchers using cynomolgus and rhesus monkeys in experimental conditions for biomedical studies.