Functional primordial germ cell-like cells from pluripotent stem cells in rats.

The in vitro generation of germ cells from pluripotent stem cells (PSCs) can have a substantial effect on future reproductive medicine and animal breeding. A decade ago, in vitro gametogenesis was established in the mouse. However, induction of primordial germ cell-like cells (PGCLCs) to produce gametes has not been achieved in any other species. Here, we demonstrate the induction of functional PGCLCs from rat PSCs. We show that epiblast-like cells in floating aggregates form rat PGCLCs. The gonadal somatic cells support maturation and epigenetic reprogramming of the PGCLCs. When rat PGCLCs are transplanted into the seminiferous tubules of germline-less rats, functional spermatids-that is, those capable of siring viable offspring-are generated. Insights from our rat model will elucidate conserved and divergent mechanisms essential for the broad applicability of in vitro gametogenesis.

Generation of Tfap2c-T2A-tdTomato knock-in reporter rats via adeno-associated virus-mediated efficient gene targeting.

Gene editing in mammalian zygotes enables us to generate genetically modified animals rapidly and efficiently. In this study, we compare multiple gene targeting strategies in rat zygotes by generating a novel knock-in reporter rat line to visualize the expression pattern of transcription factor AP-2 gamma (Tfap2c). The targeting vector is designed to replace the stop codon of Tfap2c with T2A-tdTomato sequence. We show that the combination of electroporation-mediated transduction of CRISPR/Cas9 components with adeno-associated virus-mediated transduction of the targeting vector is the most efficient in generating the targeted rat line. The Tfap2c-T2A-tdTomato fluorescence reflects the endogenous expression pattern of Tfap2c in preimplantation embryo, germline, placenta, and forebrain during rat embryo development. The reporter line generated here will be a reliable resource for identifying and purifying Tfap2c expressing cells in rats, and the gene targeting strategy we used can be widely applied for generating desired animals.

Tracing the emergence of primordial germ cells from bilaminar disc rabbit embryos and pluripotent stem cells.

Rabbit embryos develop as bilaminar discs at gastrulation as in humans and most other mammals, whereas rodents develop as egg cylinders. Primordial germ cells (PGCs) appear to originate during gastrulation according to many systematic studies on mammalian embryos. Here, we show that rabbit PGC (rbPGC) specification occurs at the posterior epiblast at the onset of gastrulation. Using newly derived rabbit pluripotent stem cells, we show robust and rapid induction of rbPGC-like cells in vitro with WNT and BMP morphogens, which reveals SOX17 as the critical regulator of rbPGC fate as in several non-rodent mammals. We posit that development as a bilaminar disc is a crucial determinant of the PGC regulators, regardless of the highly diverse development of extraembryonic tissues, including the amnion. We propose that investigations on rabbits with short gestation, large litters, and where gastrulation precedes implantation can contribute significantly to advances in early mammalian development.

Blastocyst complementation using Prdm14-deficient rats enables efficient germline transmission and generation of functional mouse spermatids in rats.

Murine animal models from genetically modified pluripotent stem cells (PSCs) are essential for functional genomics and biomedical research, which require germline transmission for the establishment of colonies. However, the quality of PSCs, and donor-host cell competition in chimeras often present strong barriers for germline transmission. Here, we report efficient germline transmission of recalcitrant PSCs via blastocyst complementation, a method to compensate for missing tissues or organs in genetically modified animals via blastocyst injection of PSCs. We show that blastocysts from germline-deficient Prdm14 knockout rats provide a niche for the development of gametes originating entirely from the donor PSCs without any detriment to somatic development. We demonstrate the potential of this approach by creating PSC-derived Pax2/Pax8 double mutant anephric rats, and rescuing germline transmission of a PSC carrying a mouse artificial chromosome. Furthermore, we generate mouse PSC-derived functional spermatids in rats, which provides a proof-of-principle for the generation of xenogenic gametes in vivo. We believe this approach will become a useful system for generating PSC-derived germ cells in the future.

Germline development in rat revealed by visualization and deletion of Prdm14.

Primordial germ cells (PGCs), the founder cells of the germline, are specified in pre-gastrulating embryos in mammals, and subsequently migrate towards gonads to mature into functional gametes. Here, we investigated PGC development in rats, by genetically modifying Prdm14, a unique marker and an essential PGC transcriptional regulator. We trace PGC development in rats, for the first time, from specification until the sex determination stage in fetal gonads using Prdm14 H2BVenus knock-in rats. We uncover that the crucial role of Prdm14 in PGC specification is conserved between rat and mice, by analyzing Prdm14-deficient rat embryos. Notably, loss of Prdm14 completely abrogates the PGC program, as demonstrated by failure of the maintenance and/or activation of germ cell markers and pluripotency genes. Finally, we profile the transcriptome of the post-implantation epiblast and all PGC stages in rat to reveal enrichment of distinct gene sets at each transition point, thereby providing an accurate transcriptional timeline for rat PGC development. Thus, the novel genetically modified rats and data sets obtained in this study will advance our knowledge on conserved versus species-specific features for germline development in mammals.

Cellular uptake mechanisms and responses to NO transferred from mono- and poly-S-nitrosated human serum albumin.

Endogenous S-nitrosated human serum albumin (E-Mono-SNO-HSA) is a large molecular weight nitric oxide (NO) carrier in human plasma, which has shown many beneficial effects in different animal models. To construct more efficient SNO-HSA preparations, SNO-HSA with many conjugated SNO groups has been prepared using chemical modification (CM-Poly-SNO-HSA). We have compared the properties of such a preparation to those of E-Mono-SNO-HSA. Cellular uptake of NO from E-Mono-SNO-HSA partly takes place via low molecular weight thiol, and it results in cytoprotective effects by induction of heme oxygenase-1. By contrast, transfer of NO from CM-Poly-SNO-HSA into the cells is faster and more pronounced. The influx mainly takes place by cell-surface protein disulfide isomerase. The considerable NO inflow results in apoptotic cell death by ROS induction and caspase-3 activation. Thus, increasing the number of SNO groups on HSA does not simply intensify the cellular responses to the product but can also result in very different effects.

Nitrosylated human serum albumin (SNO-HSA) induces apoptosis in tumor cells.

Recently, nitric oxide has been investigated as a potential anti-cancer therapy because of its cytotoxic activity. Previously, we found that S-nitrosylated human serum albumin (SNO-HSA) induced apoptosis in C26 cells, demonstrating for the first time that SNO-HSA has potential as an anti-cancer drug. In the present study, the anti-tumor activity of SNO-HSA in another tumor type of cancer cell was investigated using murine tumor LY-80 cells. Mitochondrial depolarization, activation of caspase-3 and DNA fragmentation were induced in LY-80 cells by SNO-HSA treatment in a dose-dependent manner. Inhibition of caspase activity resulted in complete inhibition of DNA fragmentation induced by SNO-HSA. The cytotoxic effects of SNO-HSA on LY-80 were concentration-dependent. Tumor growth in LY-80-tumor-bearing rats was significantly inhibited by administration of SNO-HSA compared with saline- and HSA-treatment. These results suggest that SNO-HSA has potential as a chemopreventive and/or chemotherapeutic agent because it induces apoptosis in tumor cells.

[A case of isoniazid sodium methanesulfonate induced interstitial pneumonia].

A 71-year-old male was admitted to our hospital with dyspnea on effort. He had been prescribed rifampicin, isoniazid sodium methanesulfonate (IHMS), and ethambutol for pulmonary tuberculosis, and ursodesoxycholic acid for alcoholic liver dysfunction. The chest HRCT revealed diffuse ground-glass attenuation with interlobular interstitial thickening. BALF showed lymphocytosis, and TBLB revealed organizing pneumonia. All medications were interrupted, and his respiratory failure and chest HRCT findings were improved. He started again medications excluding IHMS, his condition continued to improve further. DLST to causative IHMS was negative with peripheral blood lymphocytes, but was positive with lymphocytes from BALF. Therefore, we diagnosed this case as having IHMS induced interstitial pneumonia. In the past, 5 cases of isoniazid induced interstitial pneumonia were reported, but IHMS induced interstitial pneumonia has not been reported. Clinicians need to be aware of drug induced interstitial pneumonia by anti-tuberculosis drugs including IHMS in patients receiving anti-tuberculosis drugs.