Generation and Application of Mouse-Rat Allodiploid Embryonic Stem Cells.

Mammalian interspecific hybrids provide unique advantages for mechanistic studies of speciation, gene expression regulation, and X chromosome inactivation (XCI) but are constrained by their limited natural resources. Previous artificially generated mammalian interspecific hybrid cells are usually tetraploids with unstable genomes and limited developmental abilities. Here, we report the generation of mouse-rat allodiploid embryonic stem cells (AdESCs) by fusing haploid ESCs of the two species. The AdESCs have a stable allodiploid genome and are capable of differentiating into all three germ layers and early-stage germ cells. Both the mouse and rat alleles have comparable contributions to the expression of most genes. We have proven AdESCs as a powerful tool to study the mechanisms regulating X chromosome inactivation and to identify X inactivation-escaping genes, as well as to efficiently identify genes regulating phenotypic differences between species. A similar method could be used to create hybrid AdESCs of other distantly related species.

Laparoscopic Caudate Lobectomy for Cholangiocarcinoma of Caudate Lobe Invading Middle Hepatic Vein.

BACKGROUND: Laparoscopic hepatectomy has gained popularity in the management of malignant liver lesions in the past decade. Its safety and feasibility, with faster recovery and comparable long-term outcomes, have been widely published. Nonetheless, laparoscopic isolated caudate lobectomy is still rare and technically demanding. We herein present a video on laparoscopic total caudate lobectomy for caudate cholangiocarcinoma. METHODS: The patient is a 61-year-old man who presented with epigastric distending discomfort. A contrast-enhanced magnetic resonance imaging was performed, showing a 4.6 × 3.9 cm tumor in the caudate lobe adjacent to the inferior vena cava, middle hepatic vein, right hepatic vein, as well as the bifurcation of the main trunk of the portal pedicle. The carbohydrate antigen was elevated to 54.58 U/ml (normal < 37 U/ml), and his liver function was normal. With the preoperative diagnosis of intrahepatic cholangiocarcinoma, laparoscopic caudate lobectomy was contemplated. RESULTS: The operative time was 300 min. The estimated intraoperative blood loss was 180 ml. The patient was discharged on the seventh postoperative day without any complications. Histopathological examination showed a 4.2 cm cholangiocarcinoma (T2N0M0) with a negative margin. He received a course of adjuvant chemotherapy. No recurrence was noted upon follow-up at 6 months after the operation. CONCLUSIONS: Laparoscopic resection for caudate lobe is a feasible and safe procedure. An experienced hepatobiliary surgeon could perform the procedure in selected cases, even with hepatic vein invasion.

Rat embryonic stem cells produce fertile offspring through tetraploid complementation.

Pluripotency of embryonic stem cells (ESCs) can be functionally assessed according to the developmental potency. Tetraploid complementation, through which an entire organism is produced from the pluripotent donor cells, is taken as the most stringent test for pluripotency. It remains unclear whether ESCs of other species besides mice can pass this test. Here we show that the rat ESCs derived under 2i (two small molecule inhibitors) conditions at very early passages are able to produce fertile offspring by tetraploid complementation. However, they lose this capacity rapidly during culture due to a nearly complete loss of genomic imprinting. Our findings support that the naïve ground state pluripotency can be captured in rat ESCs but also point to the species-specific differences in its regulation and maintenance, which have implications for the derivation and application of naïve pluripotent stem cells in other species including human.

Mitigating the adverse effects of Aflatoxin B1 in LMH, IPEC-J2 and 3D4/21 cells by a novel integrated agent.

This study was to evaluate the efficacy of TOXO-XL (XL), an integrated mycotoxin-mitigating agent, on aflatoxin B1 (AFB1)-induced damage in Leghorn male hepatoma (LMH), porcine jejunum epithelial cell line (IPEC-J2) and porcine alveolar macrophages (3D4/21) cells, and to explore its potential mechanisms. The results showed that 30% inhibition concentration (IC30) of AFB1 in LMH, IPEC-J2 and 3D4/21 cells was 0.5, 15.0, and 2.5 mg/L, respectively. Notably, cell viability, ROS, apoptosis and DNA lesion induced by AFB1 (IC30) could be ameliorated by the supplementation with XL at the dosage of 0.025, 0.025 and 0.005%, respectively. Additionally, the migration and phagocytosis abilities impaired by AFB1 were also restored by XL in 3D4/21. Further experiments revealed that XL supplementation markedly attenuated AFB1-induced inflammatory response by decreasing IL-1ß, IL-6 and IL-10 in LMH, IL-6 in IPEC-J2 and IL-1ß in 3D4/21 cells. Meanwhile, XL supplementation reversed the alterations of BAX, BCL-2 and caspase-3 induced by AFB1 in the three cells, suggesting that AFB1-induced apoptosis may be suppressed via the mitochondria-dependent pathway. Furthermore, XL may have a protective effect on the intestinal barrier through the restoration of occludin protein. Conclusively, these findings indicated that XL could alleviate AFB1-induced cytotoxicity in the three cells, potentially through the regulation of cytokines, ROS, apoptotic and DNA damage signaling.

Overcoming Intrinsic H3K27me3 Imprinting Barriers Improves Post-implantation Development after Somatic Cell Nuclear Transfer.

Successful cloning by somatic cell nuclear transfer (SCNT) requires overcoming significant epigenetic barriers. Genomic imprinting is not generally regarded as such a barrier, although H3K27me3-dependent imprinting is differentially distributed in E6.5 epiblast and extraembryonic tissues. Here we report significant enhancement of SCNT efficiency by deriving somatic donor cells carrying simultaneous monoallelic deletion of four H3K27me3-imprinted genes from haploid mouse embryonic stem cells. Quadruple monoallelic deletion of Sfmbt2, Jade1, Gab1, and Smoc1 normalized H3K27me3-imprinted expression patterns and increased fibroblast cloning efficiency to 14% compared with a 0% birth rate from wild-type fibroblasts while preventing the placental and body overgrowth defects frequently observed in cloned animals. Sfmbt2 deletion was the most effective of the four individual gene deletions in improving SCNT. These results show that lack of H3K27me3 imprinting in somatic cells is an epigenetic barrier that impedes post-implantation development of SCNT embryos and can be overcome by monoallelic imprinting gene deletions in donor cells.

Nicotinamide induces liver regeneration and improves liver function by activating SIRT1.

Nicotinamide (Nam) has recently been characterized as an agent for tissue regeneration due to the observed pro­proliferation effects. However, the effect of Nam on liver regeneration remains undetermined. In the present study, the potency of Nam as a regimen to promote liver regeneration and restore liver function was evaluated following partial hepatectomy (PH) on C57BL/6 mice. Ki­67 immunohistochemical and cell cycle analyses demonstrated that exogenous Nam supplementation promoted the proliferation of hepatocytes and accelerated the recovery of liver tissue. The addition of Nam protected liver function following PH, as evidenced by hematoxylin and eosin staining of liver tissue morphology and measurement of serum liver injury markers. Notably, immunoblotting results revealed that the expression and activity of NAD­dependent protein deacetylase sirtuin­1 (SIRT1) were significantly upregulated following treatment with Nam, suggesting that Nam may promote liver regeneration through activation of SIRT1. The present study demonstrated that Nam regulated the process of liver regeneration and improved liver function by activating SIRT1, suggesting that Nam has the potency to be used for promoting liver regeneration following surgical resection.

Generation of Bimaternal and Bipaternal Mice from Hypomethylated Haploid ESCs with Imprinting Region Deletions.

Unisexual reproduction is widespread among lower vertebrates, but not in mammals. Deletion of the H19 imprinted region in immature oocytes produced bimaternal mice with defective growth; however, bipaternal reproduction has not been previously achieved in mammals. We found that cultured parthenogenetic and androgenetic haploid embryonic stem cells (haESCs) display DNA hypomethylation resembling that of primordial germ cells. Through MII oocyte injection or sperm coinjection with hypomethylated haploid ESCs carrying specific imprinted region deletions, we obtained live bimaternal and bipaternal mice. Deletion of 3 imprinted regions in parthenogenetic haploid ESCs restored normal growth of fertile bimaternal mice, whereas deletion of 7 imprinted regions in androgenetic haploid ESCs enabled production of live bipaternal mice that died shortly after birth. Phenotypic analyses of organ and body size of these mice support the genetic conflict theory of genomic imprinting. Taken together, our results highlight the factors necessary for crossing same-sex reproduction barriers in mammals.

Generation of Mouse Haploid Somatic Cells by Small Molecules for Genome-wide Genetic Screening.

The recent success of derivation of mammalian haploid embryonic stem cells (haESCs) has provided a powerful tool for large-scale functional analysis of the mammalian genome. However, haESCs rapidly become diploidized after differentiation, posing challenges for genetic analysis. Here, we show that the spontaneous diploidization of haESCs happens in metaphase due to mitotic slippage. Diploidization can be suppressed by small-molecule-mediated inhibition of CDK1 and ROCK. Through ROCK inhibition, we can generate haploid somatic cells of all three germ layers from haESCs, including terminally differentiated neurons. Using piggyBac transposon-based insertional mutagenesis, we generated a haploid neural cell library harboring genome-wide mutations for genetic screening. As a proof of concept, we screened for Mn2+-mediated toxicity and identified the Park2 gene. Our findings expand the applications of mouse haploid cell technology to somatic cell types and may also shed light on the mechanisms of ploidy maintenance.

A non-invasive method to determine the pluripotent status of stem cells by culture medium microRNA expression detection.

To precisely determine the type and status of cells is an important prerequisite for basic researches and regenerative medicine involving stem cells or differentiated cells. However, the traditional destructive cell status examination methods have many limitations, mainly due to the heterogeneity of cells under the reprogramming or differentiation/trans-differentiation process. Here we present a new method to non-destructively determine the pluripotent level of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), or the types of differentiated cells. The method is achieved by examining the expression profiles of microRNAs (miRNAs) in cell culture medium, which show consistent abundance trend as those of the cellular miRNAs. Therefore, the method enables status examination and afterward application being achieved on the same population of cells, which will greatly facilitate cell reprogramming or differentiation/trans-differentiation related based research and clinical therapy.