Publications by authors named "Ryosuke Sakumoto"

Although anti-Müllerian hormone (AMH) is involved in the regulation of granulosa cell function in female animals, its role in tissues other than ovarian follicles remains poorly understood. It has also been suggested that cows with high circulating AMH concentrations have increased fertility; however, the mechanism has not been elucidated. This study was conducted to identify the presence of the AMH-signaling system and its target cells in the bovine corpus luteum formed from an ovulated follicle.

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Pregnancy is intricately regulated by the interactions between various bioactive substances secreted by the conceptus, uterus, and corpus luteum (CL). Interferon-τ, synthesized and secreted by the conceptus, plays a central role in the interaction mechanism of maternal recognition in cows. Chemokines, chemotaxis mediators that are primarily secreted by immune cells, regulate various reproductive responses in various species.

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This study investigated the expression dynamics of bone morphogenetic protein 4 (BMP4) and its receptors (BMPR1A, BMPR1B, and BMPR2) in bovine endometrium and examined the physiological function and regulatory mechanism of BMP4 expression. The messenger RNA (mRNA) expression of BMP4 and its receptors was detected in bovine endometrium of both ipsilateral (corpus luteum [CL]-side) and contralateral (non-CL-side) uterine horns during the estrous cycle and early pregnancy. BMP4 protein levels were higher in the endometrial tissues obtained from those cows in early pregnancy than in the estrous cycle.

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In cattle, the establishment of appropriate endometrial vasculature during the estrous cycle is required for preparing a receptive endometrium. This study aimed to investigate 1) mRNA expression of potent pro- and anti-angiogenic factors, 2) protein localization of the anti-angiogenic factor thrombospondin (TSP), and 3) vascularity in the endometrium of repeat breeder (RB) and normally fertile (non-RB) cows. Caruncular and intercaruncular endometrium was collected from RB and non-RB cows during the luteal phase of the estrous cycle.

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The aim of the present study was to evaluate the effects of continuous administration of linoleic acid or linolenic acid into the intra-uterine horn, ipsilateral to the corpus luteum, on the duration of the estrous cycle and plasma progesterone (P4) concentration. The effects of linoleic and linolenic acids on bovine uterine and luteal functions were also studied using a tissue culture system. Intra-uterine administration of linoleic or linolenic acid (5 mg/10 ml of each per day) in cows, between days 12 and 21, resulted in a prolonged estrous cycle compared to the average duration of the last one to three estrous cycles before administration in each group (P < 0.

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Heat stress (HS) reduces reproductive performance of cattle, possibly by disrupting endocrine regulation such as prostaglandin (PG) production from uterus and estradiol 17β production from the dominant follicle. Prostaglandin F2α (PGF2α) secretion from endometrium surges during the luteal phase due to tumor necrosis factor (TNF) α stimulation and a positive-feedback loop with oxytocin (OT) from the corpus luteum, ultimately triggering luteolysis, while interferon τ (IFNT) inhibits upregulation of PGF2α production by TNFα and OT, thereby preventing luteolysis and triggering recognition of pregnancy. In the present study, we investigated the effect of OT, TNFα, and IFNT on PGF2α production in both types of endometrial cells under HS conditions.

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Bovine leukemia virus (BLV) causes a lymphoproliferative disease in cattle and is transmitted horizontally and vertically via infected lymphocytes. Although transplacental infection is considered the predominant route of vertical transmission of BLV, the molecular mechanisms of this process remain to be elucidated. Notably, how BLV passes through the blood-placental barrier remains unclear, given that BLV is transmitted primarily by cell-to-cell contact.

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We investigated gene expression profiles of the corpus luteum (CL) at the time of maternal recognition to evaluate the functional changes of the CL during early pregnancy in cows and help improve reproductive efficiency and avoid defective fetuses. Microarray analyses using a 15 K bovine oligo DNA microarray detected 30 differentially expressed genes and 266 differentially expressed genes (e.g.

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In bovine placentomes, the inflammatory response is considered important for the detachment of the fetal membrane from the caruncle after parturition. Glucocorticoids, a trigger of the onset of parturition, facilitate functional maturation of placentomes via prostaglandin (PG) and estrogen production in cattle. This study investigated how exogeneous glucocorticoids, which exert immunosuppressive effects, affect placental inflammation at parturition.

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The mechanism by which the fetal membrane detaches after parturition in cattle is poorly understood, but the upregulation of placentomal prostaglandin and estrogen synthesis are considered to be important. This study investigated whether enhanced glucocorticoid exposure affected the functional maturation of placentomes at induced parturition. Placentomes were collected immediately after spontaneous (beef; n = 5, dairy; n = 5) or induced parturition in beef and dairy cattle.

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The aim of this study was to determine endometrial mRNA expression patterns and uterine protein localizations of vascular endothelial growth factor (VEGF) ligands (VEGFA, VEGFB, VEGFC, and VEGFD) and their receptors (VEGFR1, soluble VEGFR1 (sVEGFR1), VEGFR2, and VEGFR3) during the peri-implantation period in cows. The number of blood and lymphatic vessels in the bovine uterus was also investigated. Bovine uterine tissues were collected from pregnant animals on days 15, 18, and 27 after artificial insemination and from non-pregnant animals on days 15 and 18 of the estrous cycle (day 0 = day of estrus).

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In order to help elucidate the process of epiblast and trophoblast cell differentiation in bovine embryos invitro, we attempted to develop a suitable culture medium to allow extended embryo culture. Day 7 bovine blastocysts developed in conventional medium were cultured further in embryonic stem cell medium with or without leukaemia inhibitory factor (LIF) until Day 23. At Day 14, the expression of octamer-binding transcription factor 3/4 (OCT3/4) and VIMENTIN was significantly higher in embryos cultured with than without LIF, but embryonic disc formation was not observed.

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Interferon-tau (IFNT), a type I interferon (IFN), is known as pregnancy recognition signaling molecule secreted from the ruminant conceptus during the preimplantation period. Type I IFNs, such as IFN-alpha and IFN-beta, are known to activate cell-death pathways as well as induce apoptosis. In cows, induction of apoptosis with DNA fragmentation is induced by IFNT in cultured bovine endometrial epithelial cells.

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Background: The aim of the present study was to evaluate and expression and its regulatory mechanism in peripheral blood leukocytes (PBLs) at the time of maternal recognition in cows. Blood samples were collected on 14, 15, 16, 17 and 18 d after artificial insemination (AI). Based on the day of return of estrus, cows were divided into three groups, pregnant ( = 5), early embryonic mortality (EEM;  = 5) and late embryonic mortality (LEM;  = 5).

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The objective of this study was to generate recombinant bovine interferon tau (rbIFNT) in mammalian hosts. The complementary DNA encoding bovine IFNT2 was cloned for the construction of pRcRSV-bIFNT2 expression vector. The expression vector was transfected to 293 cells.

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The aim of the present study was to determine the possible roles of chemokines in regulating bovine endometrial function during early pregnancy. The expression of six chemokines, including CCL2, CCL8, CCL11, CCL14, CCL16, and CXCL10, was higher in the endometrium at 15 and 18 days of pregnancy than at the same days in non-pregnant animals. Immunohistochemical staining showed that chemokine receptors (CCR1, CCR2, CCR3, and CXCR3) were expressed in the epithelial cells and glandular epithelial cells of the bovine endometrium as well as in the fetal trophoblast obtained from a cow on day 18 of pregnancy.

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Background: Repeat breeding directly affects reproductive efficiency in cattle due to an increase in services per conception and calving interval. This study aimed to investigate whether changes in endometrial gene expression profile are involved in repeat breeding in cows. Differential gene expression profiles of the endometrium were investigated during the mid-luteal phase of the estrous cycle between repeat breeder (RB) and non-RB cows using microarray analysis.

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The main function of the bovine corpus luteum (CL) is the production of progesterone. Adequate luteal progesterone is crucial for determining the physiological duration of the estrous cycle and for achieving a successful pregnancy. The CL is regulated not only by hypophyseal gonadotropin, but also by a number of intraluteal substances including steroids, peptides and prostaglandins.

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Heat stress compromises fertility during summer in dairy and beef cows by causing nutritional, physiological and reproductive damages. To examine the difference in endometrial conditions in cows between summer and autumn, gene expression profiles were compared using a 15 K bovine oligo DNA microarray. The trial was conducted in the summer (early in September) and autumn (mid-November) seasons of two consecutive years (2013-2014) in Morioka, Japan.

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We recently demonstrated that luteal cells flow out from the ovary via lymphatic vessels during luteolysis. However, the regulatory mechanisms of the outflow of luteal cells are not known. Matrix metalloproteinases (MMPs) can degrade the extracellular matrix and basal membrane, and tissue inhibitors of matrix metalloproteinases (TIMPs) inhibit the activity of MMPs.

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Progesterone (P4) acts through different actuating pathways called genomic and non-genomic pathways. Here we investigated whether P4 regulates prostaglandin (PG) F2? (PGF) and PGE2 production in bovine endometrium through different pathways. Cultured endometrial cells were exposed to P4 for a short time (5-20min) or bovine serum albumin (BSA)-conjugated P4 (P4-BSA) for 24h.

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To determine functional differences between the corpus luteum (CL) of the estrous cycle and pregnancy in cows, gene expression profiles were compared using a 15 K bovine oligo DNA microarray. In the pregnant CL at days 20-25, 40-45 and 150-160, the expressions of 138, 265 and 455 genes differed by a factor of > 2-fold (P < 0.05) from their expressions in the cyclic CL (days 10-12 of the estrous cycle).

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The bovine corpus luteum (CL) is hypothesized to utilize a local auto-amplification system for prostaglandin (PG) F2α production. The objective of the present study was to determine if such a PGF2α auto-amplification system exists in the bovine CL, and if so, which factors regulate it. PGF2α significantly stimulated intra-luteal PGF2α production in all luteal phases, but did not affect PGE2 production.

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The rapid growth of the corpus luteum (CL) after ovulation is believed to be mainly due to an increase in the size of luteal cells (hypertrophy) rather than an increase in their number. However, the relationship between luteal growth and the proliferation of luteal steroidogenic cells (LSCs) is not fully understood. One goal of the present study was to determine whether LSCs proliferate during CL growth.

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Background: Adrenomedullin (AM) is a potent vasodilator peptide and is also involved in various physiological activities. In humans and rodents, AM is found in the uteroplacental unit and may be responsible for fetal development and maintenance of placental function. This study investigated 1) the mRNA expression patterns of AM and its receptor components (calcitonin receptor-like receptor (CRLR), receptor activity modifying protein (RAMP) 2 and RAMP3) during pregnancy and 2) mRNA and protein localization of AM, CRLR and RAMPs in the bovine placentome.

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