Reproduction最新文献

In brief: Formation and function of the corpus luteum strongly rely on active angiogenesis. This study demonstrates the role of the hypoxia-inducible factor (HIF) in luteinization with no effect on fertility.

Abstract: HIFs are transcription factors responsible for sensing low oxygen levels and, in response, inducing the transcription of numerous genes. One of the main processes stimulated by HIFs is the formation of new vessels to increase oxygen supply to the tissue. Formation of the corpus luteum strongly depends on the vasculature, and active angiogenesis occurs during luteinization. In this study, we aimed to analyze the role of HIF in the early formation of corpus luteum and its function, and in female fertility. To this aim, we superovulated mice using equine chorionic gonadotropin and human chorionic gonadotropin (hCG) and administered the HIF inhibitor acriflavine (ACF) to the mice 3 h before hCG. We found a decrease in ovarian HIF1A and VEGFA and in the vascular area in the animals treated with ACF. Moreover, we observed an increase in aberrant structures in the ovaries and in luteal cell apoptosis. Serum progesterone levels were decreased together with ovarian STAR expression. However, the animals treated with ACF during the early formation of the corpus luteum were completely fertile and no alterations were observed when the treated females were mated with fertile males. These results collectively suggest that HIF regulates gonadotropin-induced corpus luteum formation by acting on luteal blood vessel formation, luteal cell survival and progesterone synthesis. However, adequate HIF activity may not be essential to achieve and maintain pregnancy. These findings are significant to better understand the complex mechanisms of corpus luteum formation and identify potential abnormalities to allow better knowledge of ovarian physiology and pathologies in which this factor could be involved.

In brief: PI3K-AKT signaling activates steroidogenesis by inducing estradiol and progesterone production, while MEK-ERK1/2 signaling regulates steroidogenesis by inhibiting estradiol and inducing progesterone production in granulosa cells (GCs). Both pathways are essential for glycolytic and mitochondrial metabolism in these cells.

Abstract: The PI3K-AKT and MEK-ERK1/2 signaling pathways are integral to fundamental cellular processes, such as proliferation, viability and differentiation. In GCs, these pathways are activated by follicle-stimulating hormone (FSH) and IGF1 through respective receptors. We investigated the comparative transcriptome changes induced by the AKT and ERK (ERK1/2) pathways using corresponding inhibitors in GCs. GCs isolated from antral follicles showed positive signals for phospho-AKT and phospho-ERK proteins. Treatment of cultured GCs with FSH and IGF1 induced phospho-AKT and phospho-ERK levels. Transcriptome analysis revealed 1436 genes regulated by AKT and 654 genes regulated by the ERK pathway. Among these, 94 genes were commonly downregulated and 11 genes were commonly upregulated in both datasets, while 110 genes were oppositely regulated. Bioinformatics analysis revealed that the inhibition of the PI3K-AKT and MEK-ERK pathways downregulates key reproductive processes and upstream molecules. Notably, AKT inhibition affected FSH, ESRRG and HIF1 pathways, while ERK inhibition impacted CG, FOS, TGFβ, EGR1 and LH pathways. Transcriptome data showed that genes related to estradiol production were inhibited by ERK and induced by the AKT pathway. This was verified by radioimmunoassays, and mRNA and protein analysis of CYP19A1 and STAR genes. In addition, transcriptome data suggested the downregulation of glucose metabolism in GCs. Using validation experiments, we confirm that both pathways are essential for glucose uptake, lactate production and mitochondrial activity in GCs. These data provide a resource for informing future research for analyzing various novel candidate genes regulated by the AKT and ERK pathways in GCs and other cell types.

In brief: This study demonstrated that metabolic syndrome (MetS) in mice disrupts the estrous cycle, increases progesterone levels and alters the endometrial structure, resulting in impaired reproductive success. Treatment with metformin effectively reversed these effects, restoring hormonal balance and normal endometrial architecture and improving reproductive outcomes.

Abstract: MetS is increasingly associated with impaired reproductive health. This study aimed to assess the endometrial characteristics and reproductive outcomes of a female MetS mouse model and evaluate metformin's therapeutic effects. Twenty-one-day-old female C57BL/6 mice were randomly divided into a high-fat (HF) diet group (n = 50) and a control group (n = 30) that received standard chow. After 11 weeks, a subset of HF mice (n = 25) was given oral metformin at 300 mg/kg/day, while the other ones continued on HF diet. After 15 weeks, mice were either sacrificed during estrus or mated and euthanized on day 7.5 of pregnancy (n = 15 per group). The estrous cycle, progesterone and estradiol levels, uterine morphology, endometrial cell proliferation, reproductive performance and metformin's treatment effects were assessed. Mice on the HF diet developed MetS, which was characterized by moderate glycemic dysregulation, increased cholesterol, insulin resistance and central obesity. Experimental MetS caused estrous cycle disruptions and increased serum progesterone levels, which were normalized by metformin. MetS also affected endometrial histology, producing hyperplasia and altering cell proliferation, while metformin restored the normal endometrial architecture by inhibiting cell proliferation. In addition, MetS impaired the reproductive success by delaying coitus and reducing the ratio of implantation sites to corpora lutea, both of which were rectified by metformin. In conclusion, MetS adversely affects reproductive function, but metformin offers improvement. Our findings highlight the need for further research on the impact of MetS on reproduction and the exploration of treatments to enhance reproductive health in women with MetS.

In brief: Modes of reproduction across limbed vertebrates are diverse, but the molecular mechanisms required for the development and maintenance of reproductive tract tissue architecture are poorly understood. This paper describes gene expression changes across the regions of the reproductive tract of the adult female brown anole, Anolis sagrei.

Abstract: The morphological diversity and functional role of the organs of the female reproductive system across tetrapods (limbed vertebrates) are relatively poorly understood. Although some features are morphologically similar, species-specific modification makes comparisons between species and inference about evolutionary origins challenging. In combination with the study of morphological changes, studying differences in gene expression in the adult reproductive system in diverse species can clarify the function of each organ. Here, we use the brown anole, Anolis sagrei, to study gene expression differences within the reproductive tract of the adult female. We generated gene expression profiles of four biological replicates of the three regions of the female reproductive tract, the infundibulum, glandular uterus, and nonglandular uterus, by RNA-sequencing. We aligned reads to the recently published A. sagrei genome and identified significantly differentially expressed genes between the regions using DESeq2. Each organ expressed approximately 14,600 genes, and comparison of gene expression profiles between organs revealed between 367 and 883 differentially expressed genes. We identify shared and region-specific transcriptional signatures for the three regions and compare gene expression in the brown anole reproductive tract to known gene expression patterns in other tetrapods. We find that genes in the Hox cluster have an anterior-posterior, collinear expression pattern as has been described in mammals. We also define a secretome for the glandular uterus. These data provide fundamental information for functional studies of the reproductive tract organs in the brown anole and an important phylogenetic anchor for comparative studies of the evolution of the female reproductive tract.

In brief: Ovine conceptuses highly express phospholipase inhibitory genes just before the conceptus attachment period. Phospholipase inhibitors could synergistically work with the interferon pathway on the endometrium.

Abstract: In mammals, various molecules are involved in the biochemical interaction between the conceptus and endometrium for pregnancy recognition and establishment. In ruminants, interferon tau (IFNT) is the pregnancy recognition factor; however, IFNT alone does not explain corpus luteum maintenance. Although data on factors expressed during implantation have been accumulated, we hypothesized that the conceptus produces additional uncharacterized molecules during the period of conceptus attachment. This study aimed to identify new conceptus secretory proteins involved in the biochemical interaction between the conceptus and endometrium in sheep. We analyzed RNA-sequence data of ovine conceptuses from pregnant animals on days 12, 14, 15, 16, 17, 19, 20 and 21. To identify novel secretory proteins, we focused on highly expressed but uncharacterized genes and performed in silico protein function analysis, identifying genes encoding phospholipase inhibitory proteins expressed on days 14 and 15. Recombinant proteins from these genes were produced, and the effects on cultured bovine endometrial epithelial cells (EECs) and stromal cells (STRs) were analyzed by RNA-sequence analysis. Differentially expressed gene (DEG) analysis demonstrated that the recombinant protein treatment upregulated 31 genes and downregulated 4 genes in EECs; it also upregulated 398 genes and downregulated 66 genes in STRs, including implantation-related genes, such as ISG15, OAS1X, OAS1Y, PARP9, PARP14, MX1 and PTGS2. Gene set enrichment analysis revealed that DEGs were enriched in several implantation-related pathways, including ISG15 antivirus mechanisms. These results suggest that, in addition to numerous characterized molecules, phospholipase inhibitory protein is a new candidate molecule in enabling biochemical communication between the conceptus and endometrium.

In brief: Exposure to phthalates, known endocrine-disrupting chemicals (EDCs), is ubiquitous, but the effects on women's reproductive health are largely unknown. This review summarizes the literature investigating associations between phthalate exposures and clinical reproductive outcomes and reproductive disease states in women, and it emphasizes the need to investigate the effects of phthalate mixtures on women's reproductive health.

Abstract: Daily exposure to a mixture of phthalates is unavoidable in humans and poses a risk to reproductive health because they are known EDCs. Specific to female reproductive health, the literature has linked phthalate exposure to impairments in ovarian function, uterine function, pregnancy outcomes and endocrine signaling in the hypothalamic-pituitary-ovarian axis. However, limitations of these studies are that they primarily focus on single-phthalate exposures in animal models. Thus, the effects of real-life exposures to mixtures of phthalates and the clinical and translational impacts on reproductive function in women are largely unknown. This review summarizes the recent literature specifically investigating associations between phthalate mixture exposures and clinical reproductive outcomes and reproductive disease states in women. Because these studies are scarce, they are supplemented with the literature utilizing single-phthalate analyses in women and mechanistic basic science studies using phthalate mixture exposures. Main findings from the literature suggest that elevated phthalate exposure is associated with altered menstrual cyclicity, altered pubertal timing, disrupted ovarian folliculogenesis and steroidogenesis, ovarian disorders including primary ovarian insufficiency and polycystic ovary syndrome, uterine disorders including endometriosis and leiomyomas, poor in vitro fertilization outcomes and poor pregnancy outcomes. There is an urgent need to better incorporate phthalate mixtures in epidemiology (mixture analyses) and basic science (direct exposures) study designs. Furthermore, as exposure to multiple phthalates is ubiquitous, elucidating the mechanism of phthalate mixture toxicities is paramount for improving women's reproductive health.

In brief: The HIPPO signaling effectors YAP1 and WWTR1 are required for murine pregnancy initiation, and mutation of these factors compromises the decidualization response and overall pregnancy success.

Abstract: Endometrial stromal cell decidualization is required for pregnancy success. Although this process is integral to fertility, many of the intricate molecular mechanisms contributing to decidualization remain undefined. One pathway that has been implicated in endometrial stromal cell decidualization in humans in vitro is the HIPPO signaling pathway. Two previously conducted studies showed that the effectors of the HIPPO signaling pathway YAP1 and WWTR1 are required for decidualization of primary endometrial stromal cells in vitro. To investigate the in vivo role of YAP1 and WWTR1 in decidualization and pregnancy initiation, we generated progesterone receptor Cre-mediated mutation of a combination of Yap1 and Wwtr1 alleles. Female Yap1 and Wwtr1 triple allele mutants exhibited subfertility, a compromised decidualization response, decreased endometrial receptivity, delayed embryonic development and a unique transcriptional profile at 7.5 days post-coitus (dpc). Bulk mRNA sequencing revealed aberrant maternal remodeling evidenced by significant alterations in extracellular matrix-encoding genes at 7.5 dpc in mutant dams and enrichment for terms associated with fertility-compromising diseases such as pre-eclampsia and endometriosis. In addition, differentially expressed genes overlapped directionally with estrogen receptor- and epidermal growth factor receptor-regulated genes as identified by microarray. Our results indicate that Yap1 and Wwtr1 are necessary for successful mammalian pregnancy initiation.

In brief: Particulate matter (PM) air pollution contains many chemicals that are individually known to have adverse effects on reproduction, as well as numerous others that have not been investigated for effects on reproduction. This review discusses the scientific literature investigating the effects of ambient and experimentally generated PM mixtures on reproduction.

Abstract: PM air pollution consists of liquid and solid particles, which are categorized by size as less than 10 (PM10) μm, 2.5 (PM2.5) μm, or 0.1 μm (PM0.1 or ultrafine) in aerodynamic diameter and which vary in composition depending on the sources. PM exposure is ubiquitous and has been associated with many adverse health effects. This narrative review focuses on epidemiological and experimental studies that investigated the effects of PM exposure on female and male reproduction and on pregnancy.