Project description:The Dummerstorf high-fertility mouse line FL1 is a worldwide unique selection experiment for increased female reproductive performance. After more than 190 generations of selection, these mice doubled the amount of offspring per litter compared to the unselected control line. FL1 females have a superior lifetime fecundity and the highest Silver fecundity index that has been described in mice, while their offspring show no signs of growth retardation. The reasons for the increased reproductive performance remained unclear. Thus, this study aims to characterize the Dummerstorf high-fertility mouse line FL1 on endocrine and molecular levels on the female side. We analyzed parameters of the hypothalamic pituitary gonadal axis on both hormonal and transcriptional levels. Gonadotropin-releasing hormone and follicle-stimulating hormone (FSH) concentrations were decreased in FL1 throughout the whole estrous cycle. Luteinizing hormone (LH) was increased in FL1 mice in estrus. Progesterone concentrations were decreased in estrus in FL1 mice and not affected in diestrus. We used a holistic gene expression approach in the ovary to obtain a global picture of how the high-fertility phenotype is achieved. We found several differentially expressed genes in the ovaries of FL1 mice that are associated with different female fertility traits. Our results indicate that ovulation rates in mice can be increased despite decreased FSH levels. Cycle-related alterations of progesterone and LH levels have the potential to improve follicular maturation, and interactions of endocrine and molecular factors lead to enhanced follicular survival, more successful folliculogenesis and therefore higher ovulation rates in female FL1 mice.
Project description:Animals in transport are exposed to both psychological and physical stressors, which affect performance and health. The objectives of this study were to investigate whether and how the transportation stress effect on female reproduction in mice, and detect differentially expressed genes association with stress response and reproductive capacity utilizing gene expression profiles. After transported mice by car to and from laboratory for a total period of 10 h, nearly 1000 km distance, measurements were carried out to explore effects of transportation stress on reproductive traits including puberty, estrous cycle, follicular number within ovaries, fertility and superovulation quality. Early life stress suffered mice before puberty promoted puberty onset, altered estrous cycle length and reduced large antral follicle number. Pubertal and adult mice exposure to transportation stress induced their pregnancy rate decline. Furthermore, adult stressed mice showed an obvious reduction in fertility with less litter size and litter weight in birth, which may cause reduced ovulation oocytes identified by superovulation. Assuming ovulated oocytes number as reproductive parameter, genes differently expressed between mice with extremely high and extremely low oocytes were compared within control and stress group separately.
Project description:Both environmental and genetic factors can dramatically affect reproductive performance in mice. In this study we have focused on the identification of genetic regions, quantitative trait loci (QTL), which affect the breeding capacity of female mice. We have identified polymorphic microsatellite markers for the mouse strains used and performed a genomewide scan on 237 females from a gene-segregating backcross between a high breeder and a relatively poor breeder. The high-breeder mouse strain we used is the inbred NFR/N mouse (MHC haplotype H-2q), which has extraordinary good breeding properties. The moderate breeder chosen for F(1) and N2 progeny was B10.Q, which is a genetically well-characterized MHC-congenic mouse of the H-2q haplotype. Each of the 237 females of the N2 generation was allowed to mate twice with MHC-congenic B10.RIII (H-2r) males and twice with B10.Q males. A predetermined number of phenotypes related to reproductive performance were recorded, and these included litter size, neonatal growth, and pregnancy rate. Loci controlling litter size were detected on chromosomes 1 (Fecq3) and 9 (Fecq4). The neonatal growth phenotype was affected by Fecq3 and a locus on chromosome 9 (Neogq1). On chromosome 11 two loci affecting the pregnancy rate (Pregq1 and Pregq2) were identified. Furthermore, on chromosomes 13 and 17 we found loci (Pregq3 and Pregq4) influencing the outcome of allogeneic pregnancy (allogeneic by means of MHC disparity between mother and fetuses). A locus on chromosome 1 affecting maternal body weight was also identified and has been denoted Bwq7. It is well known that reproductive performance is polygenically controlled, and the identification of the major loci in this complex process opens the possibility of investigating the natural genetic control of reproduction.
Project description:Ovarian development requires coordinate communications among oocytes, granulosa cells, and theca cells. Two Hedgehog (Hh) pathway ligands, Desert hedgehog (Dhh) and Indian hedgehog (Ihh), are produced by the granulosa cells and work together to regulate theca cell specification and development. Mice lacking both Dhh and Ihh had loss of normal ovarian function, which raised the question of which biological actions are specifically controlled by each ligand during folliculogenesis. By comparing the reproductive fitness, hormonal profiles, and ovarian transcriptomes among control, Dhh single-knockout (KO), Ihh KO, and Dhh/Ihh double-knockout (DKO) mice, we examined the specific roles of Dhh and Ihh in these processes. Dhh/Ihh DKO female mice were infertile because of a lack of theca cells and their steroid product androgen. Although Dhh and Ihh KO mice were fertile with normal folliculogenesis, they had decreased androgen production and alterations in their ovarian transcriptomes. Absence of Ihh led to aberrant steroidogenesis and elevated inflammation responses, which were not found in Dhh KO mouse ovaries, implicating that IHH has a greater impact than DHH on the activation of the Hh signaling pathway in the ovary. Our findings provide insight into not only how the Hh pathway influences folliculogenesis but also the distinct and overlapping roles of Dhh and Ihh in supporting ovarian development.
Project description:The aim of this study was to evaluate the effect of an environmental enrichment (EE) plan on the reproductive performance of Swiss Webster mice and their female offspring used as recipients for embryo transfer. A total of 54 breeder mice and 60 F1 females, used as foster mothers, were allocated in two experimental groups to receive or not receive EE for physical well-being. Reproductive outcomes of the Swiss trios such as birth rate and pup number, litter size, pups' weight at weaning, interlitter interval and time to first litter were analyzed. Environmental enrichment significantly increased pups weight from breeding trios compared to the control group (14.4 ± 0.1 vs. 13.8g ± 0.1, EE vs. control, respectively; p < 0.01). Other parameters did not differ between both groups. Reproductive parameters of female offspring used as recipients for embryo transfer did not differ among groups subjected or not to EE. These data demonstrate that the EE protocol applied in Swiss Webster breeder mice positively enhanced pups weight, and did not interfere with other reproductive outcomes. In conclusion, this study supports the implementation of EE plans usually applied for animal welfare in mouse facilities with slight improvement in reproductive performance.
Project description:Out of millions of ejaculated sperm, a few reach the fertilization site in mammals. Flagellar Ca2+ signaling nanodomains, organized by multi-subunit CatSper calcium channel complexes, are pivotal for sperm migration in the female tract, implicating CatSper-dependent mechanisms in sperm selection. Here using biochemical and pharmacological studies, we demonstrate that CatSper1 is an O-linked glycosylated protein, undergoing capacitation-induced processing dependent on Ca2+ and phosphorylation cascades. CatSper1 processing correlates with protein tyrosine phosphorylation (pY) development in sperm cells capacitated in vitro and in vivo. Using 3D in situ molecular imaging and ANN-based automatic detection of sperm distributed along the cleared female tract, we demonstrate that spermatozoa past the utero-tubal junction possess the intact CatSper1 signals. Together, we reveal that fertilizing mouse spermatozoa in situ are characterized by intact CatSper channel, lack of pY, and reacted acrosomes. These findings provide molecular insight into sperm selection for successful fertilization in the female reproductive tract.
Project description:As age at pubertal onset declines and age at first pregnancy increases, the mechanisms that regulate female reproductive lifespan become increasingly relevant to population health. The timing of menarche and menopause can have profound effects not only on fertility but also on the risk of diseases such as type 2 diabetes mellitus, cardiovascular disease and breast cancer. Genetic studies have identified dozens of highly penetrant rare mutations associated with reproductive disorders, and also ∼175 common genetic variants associated with the timing of puberty or menopause. These findings, alongside other functional studies, have highlighted a diverse range of mechanisms involved in reproductive ageing, implicating core biological processes such as cell cycle regulation and energy homeostasis. The aim of this article is to review the contribution of such genetic findings to our understanding of the molecular regulation of reproductive timing, as well as the biological basis of the epidemiological links between reproductive ageing and disease risk.
Project description:Endocrine resistance may develop as a consequence of enhanced growth factor signaling. Fibroblast growth factor 2 (FGF2) consists of a low and several high molecular weight forms (HMW-FGF2). We previously demonstrated that antiprogestin-resistant mammary carcinomas display lower levels of progesterone receptor A isoforms (PRA) than B isoforms (PRB). Our aim was to evaluate the role of FGF2 isoforms in breast cancer progression. We evaluated FGF2 expression, cell proliferation, and pathway activation in models with different PRA/PRB ratios. We performed lentiviral infections of different FGF2 isoforms using the human hormone-responsive T47D-YA cells, engineered to only express PRA, and evaluated tumor growth, metastatic dissemination, and endocrine responsiveness. We assessed FGF2 expression and localization in 81 human breast cancer samples. Antiprogestin-resistant experimental mammary carcinomas with low PRA/PRB ratios and T47D-YB cells, which only express PRB, displayed higher levels of HMW-FGF2 than responsive variants. HMW-FGF2 overexpression in T47D-YA cells induced increased tumor growth, lung metastasis, and antiprogestin resistance compared to control tumors. In human breast carcinomas categorized by their PRA/PRB ratio, we found nuclear FGF2 expression in 55.6% of tumor cells. No differences were found between nuclear FGF2 expression and Ki67 proliferation index, tumor stage, or tumor grade. In low-grade tumor samples, moderate to high nuclear FGF2 levels were associated to carcinomas with low PRA/PRB ratio. In conclusion, we show that HMW-FGF2 isoforms are PRB targets which confer endocrine resistance and are localized in the nuclei of breast cancer samples. Hence, targeting intracellular FGF2 may contribute to overcome tumor progression.