Publications by authors named "Shingo Tonai"

Despite the recognized importance of glycans in biological phenomena, their complex roles in spermatogenesis and sperm function remain unclear. SLC35G3, a 10-transmembrane protein specifically found in early round spermatids, belongs to the sugar-nucleotide transporter family, indicating its involvement in glycan formation. In this study, we found that knockout male mice were sterile due to impaired sperm functions in uterotubal junction passage, zona pellucida binding, and oocyte fusion.

View Article and Find Full Text PDF

Background: RIBC1 (RIB43A domain with coiled-coils 1) and RIBC2 (RIB43A domain with coiled-coils 2) are homolog proteins of RIB43a which is localized to microtubules in the cilia and flagella of unicellular organisms. Cryo-electron microscopy and artificial intelligence studies showed that RIBC1 and RIBC2 are microtubule inner proteins (MIPs) localized in the inner lumen of the doublet microtubules (DMTs) in mouse sperm flagella. However, the function of RIBC1 and RIBC2 in mammalian reproduction and sperm flagella is still unknown.

View Article and Find Full Text PDF

In vitro maturation (IVM) produces offspring from domestic animals; however, the blastocyst rate after IVM was low. We previously reported that the developmental competence of oocytes derived from follicles with blood vessels absent on the surface (non-vascularized follicles: NVF) is quite low compared to those derived from follicles with blood vessels present on the surface (vascularized follicles: VF). Thus, it is important to develop technique to improve the quality of NVF-derived oocyte by IVM.

View Article and Find Full Text PDF
Article Synopsis
  • Mice are a key model for studying human gene function due to their genetic similarities and advancements like CRISPR/Cas9 have sped up research on gene roles in male reproduction.
  • Researchers focused on 15 genes related to male fertility and created 13 gene-deficient mouse models, all of which showed normal fertility in natural breeding.
  • The study suggests that the investigated genes are not essential for male fertility, which could help streamline research efforts by preventing unnecessary duplication of studies on these non-essential genes.
View Article and Find Full Text PDF

Purpose: LH induces the expression of EGF-like factors and their shedding enzyme (ADAM17) in granulosa cells (GCs), which is essential for ovulation via activation of the ErbB-ERK1/2 pathway in cumulus cells (CCs). Neurotensin (NTS) is reported as a novel regulator of ovulation, whereas the NTS-induced maturation mechanism in oocytes remains unclear. In this study, we focused on the role of NTS in the expression of EGF-like factors and ErbBs, and ADAM17 activity, during oocyte maturation and ovulation in mice.

View Article and Find Full Text PDF

Purpose: Since the developmental competence of oocytes cultured after in vitro maturation (IVM) is low, it is necessary to improve the IVM method for efficient offspring production. In this study, we revealed that transferrin (TF)-Fe was accumulated in follicular fluid with increasing the follicular diameter, and that TF receptor (TFR1) was localized in granulosa cells of pig. Thus, we hypothesized that TF-Fe would be a factor in the induction of developmental competence of porcine oocytes.

View Article and Find Full Text PDF

Postpartum endometritis is known to be associated with ovarian dysfunction in cows. Lipopolysaccharide (LPS) generated by Gram-negative bacteria is recognized by toll-like receptor 4 (TLR4), which leads to an inflammatory response by the generation of cytokines such as tumor necrosis factor-α (TNF-α) and interleukins. In this study, we investigated the effect of endometrial LPS on granulosa cell functions during early follicular development in cows.

View Article and Find Full Text PDF

In the liver, the sterol response element binding protein (SREBP) and the SREBP cleavage-activated protein (SCAP) complex upregulate cholesterol biosynthesis by gene induction of de novo cholesterol synthetic enzymes (Hmgcr, Cyp51, and Dhcr7). Insulin induced gene 1 (INSIG1) negatively regulates cholesterol biosynthesis by the inhibition of de novo cholesterol biosynthetic gene expression. In the ovary, cholesterol is de novo synthesized; however, the roles of SREBP and its regulators (SCAP and INSIG1) are not well understood.

View Article and Find Full Text PDF

During follicular development, a few dominant follicles develop to large antral dominant follicles, whereas the remaining follicles undergo atretic degeneration. Because vascularization on the follicular surface is a morphological feature of dominant follicles, we previously classified these follicles as vascularized follicles (VFs) and non-VFs (NVFs). In NVFs, progesterone producing genes were expressed similarly to that in VFs; however, the progesterone concentration in follicular fluid was low in large NVFs.

View Article and Find Full Text PDF

Although successful fertilization is completed by only 150 sperm in the pig oviduct, more than 50,000 sperms are required to achieve a fertilization rate of more than 70% by pig in vitro fertilization (IVF). In this study, to improve the efficiency of pig IVF, the effects of hypoxic conditions and treatment with creatine and methyl-beta cyclodextrin (MβCD) on the glycolytic pathway were investigated. Under low O conditions, zig-zag motility was strongly induced within 30 min; however, the induction disappeared at 60 min.

View Article and Find Full Text PDF
Article Synopsis
  • Iron is crucial for cellular processes like energy production and cell growth, and a lack of it in the diet can lead to iron deficiency anemia (IDA).
  • A study using mice on a low iron diet showed that iron deficiency disrupted their reproductive cycles, preventing proper follicle development and ultimately leading to infertility.
  • However, when these mice were switched back to a normal diet rich in iron for three weeks, their reproductive functions and estrous cycles were completely restored, indicating that the negative effects of iron deficiency are reversible.
View Article and Find Full Text PDF