Appearance of small extracellular vesicles in the mouse pregnant serum and the localization in placentas.

Exosomes or small extracellular vesicles (sEVs) are present in the blood of pregnant mice and considered to be involved in pregnancy physiology. Although sEVs in pregnant periods are proposed to be derived from placentas, sEVs-producing cells are not well known in mouse placentas. We studied the dynamics and localization of sEVs in pregnant serum and placentas, and examined gestational variation of microRNA (miRNA). Serums and placentas were collected from non-pregnant (NP) and pregnant mice throughout the entire gestational day (Gd). EVs were purified from serums and total RNA was isolated from EVs. Nanoparticle-tracking assay (NTA) revealed that the rates of sEVs in EVs are 53% at NP, and increased to 80.1% at Gd 14.5 and 97.5% at Gd 18.5. Western blotting on EVs showed positive reactivity to the tetraspanin markers and clarified that the results using anti-CD63 antibody were most consistent with the sEVs appearance detected by NTA. Serum EVs also showed a positive reaction to the syncytiotrophoblast marker, syncytin-1. Immunohistostaining using anti-CD63 antibody showed positive reactions in mouse placentas at the syncytiotrophoblasts and endothelial cells of the fetal capillaries. Quantitative PCR revealed that significantly higher amounts of miRNAs were included in the sEVs of Gd 18.5. Our results suggested that sEVs are produced in the mouse placenta and transferred to maternal or fetal bloodstreams. sEVs are expected to have a miRNA-mediated physiological effect and become useful biomarkers reflecting the pregnancy status.

Establishment of African pygmy mouse induced pluripotent stem cells using defined doxycycline inducible transcription factors.

Mus minutoides is one of the smallest mammals worldwide; however, the regulatory mechanisms underlying its dwarfism have not been examined. Therefore, we aimed to establish M. minutoides induced pluripotent stem cells (iPSCs) using the PiggyBac transposon system for applications in developmental engineering. The established M. minutoides iPSCs were found to express pluripotency markers and could differentiate into neurons. Based on in vitro differentiation analysis, M. minutoides iPSCs formed embryoid bodies expressing marker genes in all three germ layers. Moreover, according to the in vivo analysis, these cells contributed to the formation of teratoma and development of chimeric mice with Mus musculus. Overall, the M. minutoides iPSCs generated in this study possess properties that are comparable to or closely resemble those of naïve pluripotent stem cells (PSCs). These findings suggest these iPSCs have potential utility in various analytical applications, including methods for blastocyst completion.

Specific expression and blood kinetics for relaxin 2, lipocalin 2, and tissue factor pathway inhibitor 2 at the canine placenta and pregnant bloods.

In general, humoral factors released from the placenta influence pregnancy progression, but the involvement of the canine placenta is often unidentified. We investigated specific genes in canine placentas and analyzed the blood dynamics of the translated proteins. Furthermore, RNAs are known to be released from placentas embedding in exosomes, a type of extracellular vesicles. Here, the presence of cell-free RNAs in pregnant serums was also confirmed. RNA specimens were purified from the normal healthy dog placentas and applied to RNA-Seq analysis. Expressions of frequent genes were confirmed by RT-PCR using placentas from other individuals and breeds. Relaxin (RLN) 2, lipocalin (LCN) 2, and tissue factor pathway inhibitor (TFPI) 2 were selected as high-expressed and placenta-specific genes. By western blot, the three factors were clearly detected in the pregnant serums. Quantitative analysis revealed that the amount of RLN2 increased significantly from non-pregnancy to day 41 of pregnancy. Regarding LCN2 and TFPI2, the protein serum levels elevated during pregnancy, but the statistical differences were not detected. Exosomes were found in all pregnant serums; however, the percentage was less than 6% in total extracellular vesicles. The cell-free RNA related to RLN2 was detected, but no elevation was confirmed during pregnancy. We found specific genes in the canine placenta and the transition of their translated protein into the blood. These factors may become useful tools for research on canine pregnancy and monitoring of reproductive management. Exosomes and cell-free RNA could not be found to be valid in canine reproduction.

Verification of the efficacy of deciduae for determining the genetic type of mouse embryos.

Mouse embryos in the early-implantation stage require manipulation under a microscope. While the extraction of DNA, RNA and proteins from a single sample allows for both determination of genetic type and analysis of gene expression, whole mount analysis is not possible. In this study, we explored the applicability of PCR using extraembryonic tissues, especially the decidual side tissue after isolating the embryos from implantation sites to establish a method for determining the genetic type of embryos. The implantation site was resected at each day from the date of vaginal plug confirmation, separated into embryos and deciduae. Genomic DNA were isolated separately from the embryos and the deciduae. PCR was performed using these genomic DNA, and the band patterns were compared after electrophoresis. As a result, we demonstrated that detecting embryo-derived cells in the decidua allows determination of the sex and presence of transgenes without harming the mouse embryos themselves, from 8.5 days of age. This method enables the determination of the genetic type of mouse embryos without damaging. This technique would expand the adaptations for analysis of mouse implanted embryos.

Characteristic amino acid residues in the growth hormone receptor gene on Mus minutoides underlying dwarfism.

The African pygmy mouse ( Mus minutoides ) displays a dwarfism phenotype distinctive from closely related species. This study aimed to investigate the growth hormone receptor (Ghr) gene sequence in M. minutoides . We identified several amino acid variations, including the P469L mutation. Our findings suggest that this mutation affects Ghr protein functionality, decreasing Igf1 expression and contributing to the dwarfism observed in M. minutoides . Further studies utilizing genome editing technology are necessary to elucidate the mechanisms involved in mammalian body size determination.

Effect of platelet lysate on Schwann-like cell differentiation of equine bone marrow-derived mesenchymal stem cells.

Currently, treatment for peripheral nerve injuries in horses primarily relies upon physical therapy and anti-inflammatory drugs. In humans, various treatments using mesenchymal stem cells (MSCs) are being attempted. Therefore, in this study, Schwann-like cell differentiation cultures of equine MSCs were prepared using fetal bovine serum (FBS) and equine platelet lysate (ePL). ePL increased the platelet count to 1 × 106/µl, the optimal concentration for culture. In both groups, an elongated morphology at both ends, characteristic of Schwann cells, was observed under the microscope. Real-time PCR analysis of the expression levels of neuronal markers showed that the ePL group tended to express higher levels of Nestin, Musashi1, and Pax3 than the FBS group. p75 was expressed at low levels in both groups. Immunostaining results showed localization of Nestin in both groups of differentiated cells, but the positive cell rate was significantly higher in the ePL group than in the FBS group. Overall, the ePL gro showed good results for Schwann-like cell differentiation, which may be useful for future use in the treatment of equine motor neuron disease. This knowledge could be applied translationaly in the treatment of amyotrophic lateral sclerosis in humans.Overall, the ePL group showed good results for Schwann-like cell differentiation, which may be useful for future use in the treatment of equine motor neuron disease and in the treatment of amyotrophic lateral sclerosis in humans.

Expression dynamics of Crry at the implantation sites in normal pregnancy and response against miscarriage induction.

In mammals, immune tolerance against fetal tissue has been established for normal pregnancy progression. It is known that Crry regulates complemental activity to prevent injury of the mouse embryo and extra-embryonic tissue. This study aimed to examine the expression appearance and normal localization sites of Crry in the mouse placenta. Also, the emergency responses of Crry were verified at the time of experimental miscarriage induction. Moreover, we investigated an existing similar protein of Crry in animal placentas other than mice. Crry expression level showed a peak at day 8.5 of pregnancy. Trophoblast giant cells and decidual cells indicated a positive reaction to anti-Crry antibody. After treatments of interferon-γ, Crry expression was increased significantly in the survived implantation sites as compared with the controls. However, there was no significant difference in the miscarriage-initiated sites. It disclosed that Crry distributes from the early to middle periods of the placentas and involves complement regulation at the extraembryonic tissue and decidua basalis. Crry also showed an ability to respond to risk against external initiation for urgent miscarriage. Finally, we found anti-mouse Crry antibody-bound proteins in the placenta of many animals. It suggests a potency of Crry to make an environment of immune tolerance in many types of mammal placentas.

Relationship Between Ovary Size and Anti-Müllerian Hormone Levels in Holstein-Friesian Cows.

The aim of this study was to verify the association between ovarian size and blood AMH levels in HF cows. Sixty multiparous HF cows from three herds were included in this study. The data required for calculating the ovarian volume included the "major axis (length)," "minor axis (width)," and "thickness" of the ovary. All ultrasonography (US) images were acquired at the outermost ends/poles of both the ovaries and of the follicles (>8 mm) and corpus luteum (CL); concomitantly, the blood was sampled from the jugular or coccygeal vein. Based on the ovarian images of each cow, the following ovarian size patterns were calculated using an image analysis software: (1) total area of both the left and right ovaries, (2) individual size of the large ovary, and (3) individual size of the small ovary. For each ovary area pattern, two properties were assessed: (A) presence of follicles (>8 mm) and CL, which may not secret AMH, in the ovaries and (B) absence of follicles (>8 mm) and CL in the ovaries. Serum AMH levels were measured using enzyme-linked immunosorbent assay. The correlation between ovary size and serum AMH levels was measured in terms of the aforementioned patterns and was evaluated statistically. The results of our preliminary study with ovaries from slaughter-house cows (n = 22) revealed that the "thickness" of the ovary was not necessary for estimating ovarian volume and that length and width were sufficient. A strong correlation was observed among ovarian length, width, and thickness (r > 0.96). No significant difference was observed (p > 0.05) in the mean ages or parities among the three herds. Among the ovary sizes measured in this study, the highest correlation was found between the total size of an individual large ovary (including follicular and luteal size) and AMH levels (r = 0.387, p = 0.002). This is the first study to demonstrate the correlation between total size of individual large ovaries and serum AMH levels in HF cows. US observations of the ovaries will allow for estimation of differences in AMH levels and help predict ovarian activity and superovulation performance of cows.

Mouse embryonic stem cells maintain differentiation potency into somatic lineage despite alternation of ploidy.

Vertebrates, including mammals, are considered to have evolved by whole genome duplications. Although some fish have been reported to be polyploids that have undergone additional genome duplication, there have been no reports of polyploid mammals due to abnormal development after implantation. Furthermore, as the number of physiologically existing tetraploid somatic cells is small, details of the functions of these ploidy-altered cells are not fully understood. In this present study, we aimed to clarify the details of the differentiation potency of tetraploids using tetraploid embryonic stem cells. To clarify the differentiation potency, we used mouse tetraploid embryonic stem cells derived from tetraploid embryos. We presented tetraploid embryonic stem cells differentiated into neural and osteocyte lineage in vitro and tetraploid cells that contributed to various tissues of chimeric embryos ubiquitously in vivo. These results revealed that mouse embryonic stem cells maintain differentiation potency after altering the ploidy. Our results provide an important basis for the differentiation dynamics of germ layers in mammalian polyploid embryogenesis.

Successful blastocyst production by intracytoplasmic injection of sperm after in vitro maturation of follicular oocytes obtained from immature female squirrel monkeys (Saimiri boliviensis).

Advanced reproductive technologies are being applied for the propagation of squirrel monkeys, to ensure their preservation as a genetic resource and the effective use of their gametes in the future. In the present study, oocytes and spermatozoa were collected from live squirrel monkeys, following which piezo intracytoplasmic sperm injection (ICSI) was performed using these gametes. Follicular development was induced by administering equine chorionic gonadotropin (eCG) containing inhibin antiserum to an immature squirrel monkey female. The unilateral ovary was excised after the administration of human chorionic gonadotropin (hCG), to induce ovulation, following which the larger developed follicular oocytes were collected. Follicular oocytes were prepared for ICSI using sperm from the epididymal tail of a unilateral testis extracted from a mature male. The embryos were continuously incubated in CMRL 1066 medium supplemented with 10% (v/v) fetal bovine serum. Embryo culture was performed with cumulus cells. Two experiments of ICSI carried out with three females resulted in 14 mature oocytes from the 49 cumulus-oocyte complexes collected and five embryos, three of which developed into blastocysts. These blastocysts were vitrified, thawed, and transferred to recipient monkeys, but no pregnancies resulted. In conclusion, the present study is the first to successfully produce ICSI-derived blastocysts from MII oocytes obtained by means of hormone administration (a combination of eCG+inhibin antiserum and hCG) and in vitro maturation in immature squirrel monkeys.

Histological analysis of implanted embryos in large Japanese field mouse (Apodemus speciosus) and estimation of developmental stage.

The large Japanese field mouse (Apodemus speciosus) is a small rodent species endemic to Japan. The genetic characteristics of A. speciosus include different chromosome numbers within the same species. Furthermore, A. speciosus has been used in radiation and genetic research. In the present study, a pregnant A. speciosus was obtained, and histochemical analysis of the implanted embryos was performed and compared with the developmental stages of the mouse (Mus musculus). Although there were some differences, the structures of the implanted embryos, including the primitive streak and placenta of A. speciosus were similar to those of mouse. Our study will be important for the construction of a developmental atlas of A. speciosus.

Characterization and expression of DNA sequences encoding the growth hormone gene in African Pygmy Mouse (Mus minutoides).

We determined the nucleotide sequence of the growth hormone (Gh) gene in Mus minutoides, one of the smallest mammals, where was predicted to be distinct in the functional regions between M. minutoides and Mus musculus. To investigate the evolutionary characteristics of Gh in M. minutoides, we constructed a phylogenetic tree based on the putative amino acid sequences of Gh, suggesting that the Gh of M. minutoides diverged earlier than M. musculus. Furthermore, the Gh gene expressed higher in M. minutoides than in M. musculus. Our results suggest that the specific feature of the Gh in M. minutoides is in rather the regulatory mechanism than the sequence.

The Heterochromatin Block That Functions as a Rod Cell Microlens in Owl Monkeys Formed within a 15-Myr Time Span.

In rod cells of many nocturnal mammals, heterochromatin localizes to the central region of the nucleus and serves as a lens to send light efficiently to the photoreceptor region. The genus Aotus (owl monkeys) is commonly considered to have undergone a shift from diurnal to nocturnal lifestyle. We recently demonstrated that rod cells of the Aotus species Aotus azarae possess a heterochromatin block at the center of its nucleus. The purpose of the present study was to estimate the time span in which the formation of the heterochromatin block took place. We performed three-dimensional hybridization analysis of the rod cell of another species, Aotus lemurinus. This analysis revealed the presence of a heterochromatin block that consisted of the same DNA components as those in A. azarae. These results indicate that the formation was complete at or before the separation of the two species. Based on the commonly accepted evolutionary history of New World monkeys and specifically of owl monkeys, the time span for the entire formation process was estimated to be 15 Myr at most.

Biological potentials for a family of disintegrin and metalloproteinase (ADAMDEC)-1 in mouse normal pregnancy.

Our previous research has indicated local expression of ADAMDEC-1, a family of disintegrin and metalloproteinase, was confirmed in the mouse placentas and enhancement was found in the sites for spontaneous abortion. Present study was aimed to identify biological effects of ADAMDEC-1 in pregnancy process. Syngeneic pairs of C57BL/6J mice and heterogenic mating pairs of CBA/J and DBA/2 mice were used. Pregnant mice were treated with recombinant ADAMDEC-1 protein. Vasculogenesis effects was evaluated using the Matrigel plugs including vascular endothelial growth factor singularity or combination with ADAMDEC-1. ADAMDEC-1 single effects were evaluated by tubal formation and proliferation assays using HuEht-1 endothelial cells. Expression of ADAMDEC-1 was not exactly corresponded with the time periods for miscarriage initiation. ADAMDEC-1 was distributed in normal placentas and fetuses, especially at extraembryonic ectoderm, decidua cells, uterine natural killer (uNK) cells in decidua, trophoblasts in labyrinthine zone, and hematopoietic cells in umbilical blood and fetal liver. ADAMDEC-1 treatment did not affect reproductive performances, while it elevated uNK cell recruitment in placenta and enlarged lumen sizes of the intraplacental vessels. In vitro analysis also indicated ADAMDEC-1 promoting effect on tubal formation and cell length of HuEht-1. qPCR analysis showed that ADAMDEC-1 modified placental gene expression especially for linkage of actin filament rearrangement. Our findings suggested that ADAMDEC-1 is correlated on cell shape, stability, and movement via modification of actin cytoskeleton. ADMADEC-1 suspected to regulate cellular activity of endothelial cells, trophoblasts, and uNK cells and may support normal developing of mouse placentas.

Establishment of a novel method for the production of chimeric mouse embryos using water-in-oil droplets.

Production of chimeric animals is often a necessity for the generation of genetically modified animals and has gained popularity in recent years in regenerative medicine for the reconstruction of xenogeneic organs. Aggregation and injection methods are generally used to produce chimeric mice. In the aggregation method, the chimeras are produced by co-culturing embryos and stem cells, and keeping them physically adhered, although it may not be an assured method for producing chimeric embryos. In the injection method, the chimeras are produced by injecting stem cells into the zona pellucida using microcapillaries; however, this technique requires a high degree of skill. This study aimed to establish a novel method for producing chimeric embryos via water-in-oil droplets that differs from conventional methods. In this study, embryonic stem cells and embryos were successfully isolated in the droplets, and the emergence of chimeric embryos was confirmed by co-culture for 6 h. Using this method, the control and operability of stem cell numbers could be regulated, and reproducibility and quantification were improved during the production of chimeric embryos. In addition to the conventional methods for producing chimeric embryos, the novel method described here could be employed for the efficient production of chimeric animals.

Hyper-polyploid embryos survive after implantation in mice.

Polyploids generated by natural whole genome duplication have served as a dynamic force in vertebrate evolution. As evidence for evolution, polyploid organisms exist generally, however there have been no reports of polyploid organisms in mammals. In mice, polyploid embryos under normal culture conditions normally develop to the blastocyst stage. Nevertheless, most tetraploid embryos degenerate after implantation, indicating that whole genome duplication produces harmful effects on normal development in mice. Most previous research on polyploidy has mainly focused on tetraploid embryos. Analysis of various ploidy outcomes is important to comprehend the effects of polyploidization on embryo development. The purpose of this present study was to discover the extent of the polyploidization effect on implantation and development in post-implantation embryos. This paper describes for the first time an octaploid embryo implanted in mice despite hyper-polyploidization, and indicates that these mammalian embryos have the ability to implant, and even develop, despite the harmfulness of extreme whole genome duplication.

Induction of pluripotency in mammalian fibroblasts by cell fusion with mouse embryonic stem cells.

BACKGROUND: Cell fusion is a phenomenon that is observed in various tissues in vivo, resulting in acquisition of physiological functions such as liver regeneration. Fused cells such as hybridomas have also been produced artificially in vitro. Furthermore, it has been reported that cellular reprogramming can be induced by cell fusion with stem cells. METHODS: Fused cells between mammalian fibroblasts and mouse embryonic stem cells were produced by electrofusion methods. The phenotypes of each cell lines were analyzed after purifying the fused cells. RESULTS: Colonies which are morphologically similar to mouse embryonic stem cells were observed in fused cells of rabbit, bovine, and zebra fibroblasts. RT-PCR analysis revealed that specific pluripotent marker genes that were never expressed in each mammalian fibroblast were strongly induced in the fused cells, which indicated that fusion with mouse embryonic stem cells can trigger reprogramming and acquisition of pluripotency in various mammalian somatic cells. CONCLUSIONS: Our results can help elucidate the mechanism of pluripotency maintenance and the establishment of highly reprogrammed pluripotent stem cells in various mammalian species.

Aggregation recovers developmental plasticity in mouse polyploid embryos.

Tetraploid embryos normally develop into blastocysts and embryonic stem cells can be established from tetraploid blastocysts in mice. Thus, polyploidisation does not seem to be so harmful during preimplantation development. However, the mechanisms by which early mammalian development accepts polyploidisation are poorly understood. In this study, we aimed to elucidate the effect of polyploidisation on early mammalian development and to further comprehend its tolerance using hyperpolyploid embryos produced by repetitive whole genome duplication. We successfully established several types of polyploid embryos (tetraploid, octaploid and hexadecaploid) and studied their developmental potential invitro. We demonstrated that all types of these polyploid embryos maintained the ability to develop to the blastocyst stage, which implies that mammalian cells might have basic cellular functions in implanted embryos, despite polyploidisation. However, the inner cell mass was absent in hexadecaploid blastocysts. To complement the total number of cells in blastocysts, a fused hexadecaploid embryo was produced by aggregating several hexadecaploid embryos. The results indicated that the fused hexadecaploid embryo finally recovered pluripotent cells in the blastocyst. Thus, our findings suggest that early mammalian embryos may have the tolerance and higher plasticity to adapt to hyperpolyploidisation for blastocyst formation, despite intense alteration of the genome volume.

Paraffin-embedded vertical sections of mouse embryonic stem cells.

Cultured cells are generally observed through the bottom of dishes or flasks using an inverted microscope. Two-dimensional and horizontal observation is insufficient for histological analysis of several cell lines, such as embryonic stem cells or cancer cells, because they form three-dimensional colonies. In the present study, we aimed to establish a more informative method for analysis of such stereoscopic cultured cells. We cultured mouse embryonic stem cells using a temperature-sensitive culture dish, embedded these cells in paraffin, and successfully observed vertical sections of embryonic stem cells. This vertical analysis of the stereoscopic colony emphasized structural features such as the dome shape of naïve pluripotent stem cells. This method could have the potential for analysis of three-dimensional structures and histological preservation in cultured cells.

Transient forebrain ischemia induces impairment in cognitive performance prior to extensive neuronal cell death in Mongolian gerbil (Meriones unguiculatus).

In Mongolian gerbils, bilateral common carotid artery occlusion (BCCAO) for several minutes induces ischemia, due to an incomplete circle of Willis, resulting in delayed neuronal cell death in the Cornet d'Ammon 1 (CA1) region of the hippocampus. Neuronal cell death in the hippocampus and changes in behavior were examined after BCCAO was performed for 5 min in the gerbils. One day after BCCAO, the pyramidal neurons of the CA1 region of the hippocampus showed degenerative changes (clumped chromatin in nuclei). At 5 and 10 days after BCCAO, extensive neuronal cell death was observed in the hippocampal CA1 region. Cognitive performance was evaluated by using the radial maze and passive avoidance tests. In the radial maze test, which examines win-stay performance, the number of errors was significantly higher in ischemic gerbils than in sham-operated gerbils on days 1 and 2 post-operation. In the passive avoidance test, the latency and freezing times were significantly shorter in ischemic gerbils than in sham-operated gerbils on the days 1, 2, and 4-6 post-operation. These results indicate that transient forebrain ischemia impairs cognitive performance, even immediately after the ischemic insult when there are only subtle signs of neuronal cell death.