Project description:To find genes in C. elegans oocytes associated with reproductive aging. Five replicates comparing RNA from oocyte samples collected from day 3 fem-1(hc17) animals with RNA from oocyte samples collected from day 8 fem-1(hc17) animals. Three out of five are dye-flipped.
Project description:To find genes downstream of the TGF-beta Sma/Mab pathway in C. elegans oocytes associated with reproductive aging. Eight replicates comparing RNA from oocyte samples collected from day 8 sma-2(e502);fem-1(hc17) animals with RNA from oocyte samples collected from day 8 fem-1(hc17) animals. Five out of eight are dye-flipped.
Project description:<p>Advanced maternal age is a key factor in female infertility, primarily due to declines in ovarian reserve and oocyte quality. However, the metabolic mechanisms underlying reproductive aging are still poorly understood. Here, we show that uridine levels in the plasma and ovaries of aged mice are significantly reduced compared with young controls. Building on this, we find that uridine supplementation significantly improves meiotic maturation, fertilization, and early embryonic development of aged oocytes, both in vivo and in vitro. Further microtranscriptomic analyses reveal that uridine enhances oocyte quality by inhibiting ferroptosis, enhancing mitochondrial function and removing excessive reactive oxygen species (ROS). Moreover, integrating Limited Proteolysis-Small Molecule Mapping (LiP-SMap), surface plasmon resonance (SPR) analyses and siRNA-based functional assays, we identify that uridine binds Poly(rC)-binding protein 1 (PCBP1), thereby suppressing ferroptosis and preserving mitochondrial function. In conclusion, this study demonstrates that uridine supplementation can effectively improve fertility of aged female mice. Our research also provides important insights into the role of ferroptosis in oocyte aging, thereby advancing our understanding of reproductive aging mechanisms.</p>
Project description:Advanced maternal age is a key factor in female infertility, primarily due to declines in ovarian reserve and oocyte quality. However, the metabolic mechanisms underlying reproductive aging remain unclear. Here, we show that uridine levels in the plasma and ovaries of aged mice are significantly reduced compared with young controls. Building on this, we find that uridine supplementation significantly improves meiotic maturation, fertilization, and early embryonic development of aged oocytes, both in vivo and in vitro. Further microtranscriptomic analyses reveal that uridine enhances oocyte quality by inhibiting ferroptosis and enhancing mitochondrial function. Moreover, integrating Limited Proteolysis-Small Molecule Mapping, western blot and siRNA-based functional assays, we identify that uridine binds Poly(rC)-binding protein 1, thereby suppressing ferroptosis and preserving mitochondrial function. Collectively, these findings demonstrate that uridine supplementation improves fertility in aged female mice and provide mechanistic insight into ferroptosis in oocyte aging.
Project description:Advanced age is a primary risk factor for female infertility due to reduced ovarian reserve and declining oocyte quality. However, as an important contributing factor, the role of metabolic regulation during reproductive aging is poorly understood. Here, we applied untargeted metabolomics to identify spermidine as a critical metabolite in ovaries to protect oocytes against aging. In particular, we found that spermidine level was reduced in aged ovaries and supplementation of spermidine promoted follicle development, oocyte maturation, early embryonic development and female fertility of aged mice. By micro-transcriptomic analysis, we further discovered that recovery of oocyte quality by spermidine was mediated by enhancement of mitophagy activity and mitochondrial function in aged mice, and this action mechanism was conserved in porcine oocytes under oxidative stress. Altogether, our findings demonstrate that spermidine supplementation is a potentially effective strategy to ameliorate oocyte quality and reproductive outcome of women at an advanced age.
Project description:Chromosome segregation errors in oocytes lead to the production of aneuploid eggs, which are the leading cause of pregnancy loss and of several congenital diseases such as Down syndrome. The frequency of chromosome segregation errors in oocytes increases with maternal age, especially at a late stage of reproductive life. How aging at various life stages affects oocytes differently remains poorly understood. In this study, we describe aging-associated changes in the transcriptome profile of mouse oocytes throughout reproductive life. Our single-oocyte comprehensive RNA sequencing using RamDA-seq revealed that oocytes undergo transcriptome changes at a late reproductive stage, whereas their surrounding cumulus cells exhibit transcriptome changes at an earlier stage. Calorie restriction, a paradigm that reportedly prevents aging-associated egg aneuploidy, promotes a transcriptome shift in oocytes with the up-regulation of genes involved in chromosome segregation. This shift is accompanied by the improved maintenance of chromosomal cohesin, the loss of which is a hallmark of oocyte aging and causes chromosome segregation errors. These findings have implications for understanding how oocytes undergo aging-associated functional decline throughout their reproductive life in a context-dependent manner.
Project description:Chromosome aneuploidy increases in oocytes with maternal age, and is considered the leading cause for the increased incidence of infertility, miscarriage, and birth defects. Using mRNA-Sequencing of oocytes from 12 month old mouse versus 3 month young mouse, we identified a spindle assembly checkpoint gene, BubR1, whose expression was significantly decreased. We employed a mRNA microinjection based approach to increase BubR1 expression in aging oocytes. We find that increased expression of BubR1 protects against aneuploidy and chromosome misalignment in aging oocytes. After in vitro fertilization, the embryos derived from BubR1 increased expression aging oocytes exhibited chromosome stability as robust as those of the young ones. Furthermore, following embryo transfer, these embryos showed greatly improved developmental competency, with comparable levels of full-term development to those of the young ones. These results indicate that the decline in oocyte quality may be reversible and could lead to treatments that prolong female fertility. Examination of the effect of maternal aging on the mRNA expression in the mature oocytes of the female mice. Naturally ovulated mature oocytes (MII stage) were collected from 6 young (3 month) and 6 aging (12 month) female mice (3 oocytes per mice, 18 oocytes for each group).
Project description:The mechanisms contributing to age-related deterioration of the female reproductive system are complex but aberrant protein homeostasis is a major contributor. We elucidated the exceptionally stable proteins, structures, and macromolecules that persist in ovaries and gametes throughout the reproductive aging timeline in mammals. Ovaries exhibit localized structural and cell-type specific enrichment of stable macromolecules throughout both the follicular and extrafollicular environments. Moreover, both ovaries and oocytes harbor a panel of exceptionally long-lived proteins, including cytoskeletal components, mitochondrial, and oocyte-derived proteins. The exceptional persistence of these long-lived molecules might play a critical role in both lifelong maintenance and age-dependent deterioration of reproductive tissues.
Project description:Reproductive aging occurs earlier than systemic aging as a woman’s ovarian reserve is depleted as she approaches menopause. There is considerable variability around when a woman reaches menopause, yet few contributing factors have been identified. Assessment of reproductive age involves measuring a woman’s ovarian reserve and oocyte function, which has clearly-defined parameters in in vitro fertilization. As ovarian reserve declines, Anti-Mullerian hormone levels fall and women produce fewer oocytes after ovarian stimulation. Oocyte function also declines, as fewer mature oocytes are produced and have the capacity to be fertilized. The mechanisms of these age-related declines are unclear, but may involve changes in DNA methylation, which are known to occur with age and may reflect the biological processes underlying reproductive aging. We hypothesize that DNA methylation patterns will be associated with ovarian reserve and oocyte function, and that women with poor ovarian reserve and oocyte function will experience epigenetic age acceleration and will accumulate more stochastic epigenetic mutations. To test this hypothesis, we will first perform an epigenome-wide association to examine DNA methylation patterns associated with each measure of ovarian reserve and oocyte function. Then, we will calculate epigenetic age and age acceleration, which are indicators of biological aging, and stochastic epigenetic mutations, which increase with age and may disrupt key biological pathways in an individual.