Publications by authors named "Yu Ishikawa-Yamauchi"
One of the major age-related declines in female reproductive function is the reduced quantity and quality of oocytes. Here we demonstrate that structural changes in the zona pellucida (ZP) were associated with decreased fertilization rates from 34- to 38-week-old female mice, equivalent to the mid-reproductive of human females. In middle-aged mouse ovaries, the decline in the number of transzonal projections was accompanied by a decrease in cumulus cell-oocyte interactions, resulting in a deterioration of the oocyte quality.
View Article and Find Full Text PDFInfertility is considered a global health issue as it currently affects one in every six couples, with female factors reckoned to contribute to partly or solely 50% of all infertility cases. Over a thousand genes are predicted to be highly expressed in the female reproductive system and around 150 genes in the ovary. However, some of their functions in fertility remain to be elucidated.
View Article and Find Full Text PDFIn mammals, females undergo reproductive cessation with age, whereas male fertility gradually declines but persists almost throughout life. However, the detailed effects of ageing on germ cells during and after spermatogenesis, in the testis and epididymis, respectively, remain unclear. Here we comprehensively examined the in vivo male fertility and the overall organization of the testis and epididymis with age, focusing on spermatogenesis, and sperm function and fertility, in mice.
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- The study explored using a basic culture medium, MEMα, with bovine serum albumin (AlbuMAX) for in vitro spermatogenesis in mice but found it ineffective in other animals, prompting a search for alternatives.
- Researchers identified essential components for a synthetic culture medium that promotes spermatogenesis, including antioxidants and lysophospholipids, in addition to known factors like retinoic acid and hormones.
- They developed a new technique called the PDMS-ceiling method to optimize nutrient and oxygen supply, successfully achieving in vitro spermatogenesis in rats, which previously posed challenges, and aim to improve conditions for other animal species.
Article Synopsis
- Male fertility declines with age, partly due to decreased spermatogenic activity linked to changes in the testicular environment.
- Research in mice shows a significant reduction in the number and growth of spermatogonia as they age.
- The study finds that senescent endothelial cells accumulate in the testes of older mice and that removing these cells can restore the supportive functions of younger testicular cells, indicating their role in declining fertility.
Article Synopsis
- - The classical organ culture method has limitations in mouse spermatogenesis due to uneven oxygen and nutrient supply, leading to poor development of sperm cells in tissue.
- - The new polydimethylsiloxane (PDMS)-chip ceiling method ensures consistent nutrient and oxygen delivery by flattening the tissue, enhancing spermatogenesis and especially promoting the formation of sperm cells.
- - This innovative method demonstrated increased tissue growth and effective spermatogenesis, marking a significant advancement for future tissue culture experiments and serving as a reliable test for testicular toxicity.
Article Synopsis
- A new method for in vitro spermatogenesis using rat testicular tissue has been developed, successfully reaching the haploid cell stage.
- Transgenic acrosin-EGFP rats were used to track the production of these cells during the process, alongside a metabolic analysis of the culture environment.
- The in vitro produced spermatids were able to produce healthy offspring through microinsemination, marking a significant advancement in sperm production techniques for species beyond mice.
Article Synopsis
- The study compares the gene knock-in (KI) efficiency of mouse embryonic stem (ES) cells using CRISPR/Cas9 methods, showing that using ribonucleoprotein (RNP) significantly increases KI efficiency.
- By employing a circular plasmid with homologous arms as a targeting vector, the researchers achieved successful KI in ES cell clones without the need for drug selection, streamlining the process.
- The introduction of a drug-resistant cassette allows for double DNA KI with high efficiency through a single electroporation, simplifying the creation of genetically modified mouse models for biological research.
PTBP1, a well-conserved RNA-binding protein, regulates cellular development by tuning posttranscriptional mRNA modification such as alternative splicing (AS) or mRNA stabilization. We previously revealed that the loss of Ptbp1 in spermatogonia causes the dysregulation of spermatogenesis, but the molecular mechanisms by which PTBP1 regulates spermatogonium homeostasis are unclear. In this study, changes of AS or transcriptome in Ptbp1-knockout (KO) germline stem cells (GSC), an in vitro model of proliferating spermatogonia, was determined by next generation sequencing.
View Article and Find Full Text PDFCalcium-binding proteins regulate ion metabolism and the necessary signaling pathways for the maturational events of sperm. Our aim is to identify the novel calcium-binding proteins in testis. The gene EFCAB2 (GenBank NM_026626.
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