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  • Author: Xiao Liu x
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Yue-Mao Zheng, Hui-Ying Zhao, Xiao-E Zhao, Fu-Sheng Quan, Song Hua, Xiao-Ying He, Jun Liu, Xiao-Ning He and Hui Lin

We assessed the developmental ability of embryos cloned from porcine neural stem (NS) cells, amniotic fluid-derived stem (AFS) cells, fetal fibroblast cells, adult fibroblast, and mammary gland epithelial cells. The five cell lines were transfected with enhanced green fluorescence protein gene respectively using lipofection. NS and AFS cells were induced to differentiate in vitro. Stem cells and their differentiated cells were harvested for analysis of the markers using RT-PCR. The five cell lines were used for nuclear transfer. The two-cell stage-cloned embryos derived from each cell line were transferred into the oviducts of surrogate mothers. The results showed that both NS and AFS cells expressed POU5F1, THY1 and SOX2, and they were both induced to differentiate into astrocyte (GFAP+), oligodendrocyte (GalC+), neuron (NF+, ENO2+, and MAP2+), adipocyte (LPL+ and PPARG-D+), osteoblast (osteonectin+ and osteocalcin+), myocyte (MYF6+ and MYOD+), and endothelium (PECAM1+, CD34+, CDH5+, and NOS3+) respectively. Seven cloned fetuses (28 days and 32 days) derived from stem cells were obtained. The in vitro developmental ability (morula–blastocyst rate was 28.26–30.07%) and in vivo developmental ability (pregnancy rate were 1.67–2.17%) of the embryos cloned from stem cells were higher (P<0.05) than that of the embryos cloned from somatic cells (morula–blastocyst rate was 16.27–19.28% and pregnancy rate was 0.00%), which suggests that the undifferentiated state of the donor cells increases cloning efficiency.

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Hui Peng, Haijun Liu, Fang Liu, Yuyun Gao, Jing Chen, Jianchao Huo, Jinglin Han, Tianfang Xiao and Wenchang Zhang

Nlrp2 is a maternal effect gene specifically expressed by mouse ovaries; deletion of this gene from zygotes is known to result in early embryonic arrest. In the present study, we identified FAF1 protein as a specific binding partner of the NLRP2 protein in both mouse oocytes and preimplantation embryos. In addition to early embryos, both Faf1 mRNA and protein were detected in multiple tissues. NLRP2 and FAF1 proteins were co-localized to both the cytoplasm and nucleus during the development of oocytes and preimplantation embryos. Co-immunoprecipitation assays were used to confirm the specific interaction between NLRP2 and FAF1 proteins. Knockdown of the Nlrp2 or Faf1 gene in zygotes interfered with the formation of a NLRP2–FAF1 complex and led to developmental arrest during early embryogenesis. We therefore conclude that NLRP2 interacts with FAF1 under normal physiological conditions and that this interaction is probably essential for the successful development of cleavage-stage mouse embryos. Our data therefore indicated a potential role for NLRP2 in regulating early embryo development in the mouse.

Open access

Dongmei He, Hong Zeng, Jingfei Chen, Lan Xiao, Yuhao Zhao and Nenghui Liu

Integrin β3 (ITGB3), which is the target gene of the miRNA let-7 that can be antagonized by long noncoding RNA (lncRNA) H19, is well known to have a critical role in endometrium receptivity. However, the regulation of ITGB3 in cell–cell or cell–extracellular matrix adhesion and invasion for the maintenance of early pregnancy remains unknown. This study aimed to explore the role of the H19/let-7/ITGB3 axis in regulating trophoblastic spheroid adhesion and in vitro invasion ability using the HTR-8/SVneo cell line and to investigate the expression levels of lncRNA H19 and ITGB3 in human products of conception. The in vitro knockdown of H19 resulted in decreased expression of ITGB3 at the mRNA and protein levels and reduced the adhesion and invasion ability. In the embryonic chorion tissue of spontaneous abortion (SA), the expressions of H19 and ITGB3 at both the mRNA and protein levels decreased. The results of quantitative RT-PCR, Western blot analysis, dual-luciferase report gene and functional miRNA let-7 rescue experiments, adhesion assay and in vitro transwell invasion assay confirmed that H19 regulated trophoblastic spheroid adhesion with endometrial stromal cells through the H19/let-7/ITGB3 axis, thereby providing an improved understanding of the molecular mechanism of SA.

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Yan Xu, Miao Liu, Yi-hua Gu, Xiao-feng Jia, Yong-Mei Chen, Michelle Santos, Ai-Zhen Wu, Xiao-dong Zhang, Hui-Juan Shi and Ching-Ling C Chen

With tetraspanning topology, members of the membrane-spanning four-domain subfamily A (MS4A) may facilitate signaling or ion channel functions in many tissues. In this study, we report the cloning of a full-length cDNA from rat testis, designated Ms4a14 (Sp3111), which encodes the MS4A protein with 1139 amino acid residues. In situ hybridization and immunohistochemical analyses indicate that Ms4a14 is predominantly expressed from round spermatids to spermatozoa at specific stages in the rat testis at both the mRNA and protein level. Immunofluorescence analysis revealed that MS4A14 (SP3111) is located in the acrosome and the midpiece of the flagellum in mature sperm. Previously, we explored and reported the involvement of MS4A14 in reproductive functions, using antibody blockage during IVF and a transgenic RNA interference method in a mouse model. Our results suggested that MS4A14 is involved in fertilization and zygote division. As MS4A14 protein exists in mammals, such as humans, cows, dogs, and rodents, MS4A14 may play a ubiquitous role in mammalian reproduction.

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Meng-Ling Liu, Jing-Lei Wang, Jie Wei, Lin-Lin Xu, Mei Yu, Xiao-Mei Liu, Wen-Li Ruan and Jia-Xiang Chen

Tri-ortho-cresyl phosphate (TOCP) has been widely used as plasticizers, plastic softeners, and flame retardants in industry and reported to have a deleterious effect on the male reproductive system in animals besides delayed neurotoxicity. Our preliminary results found that TOCP could disrupt the seminiferous epithelium in the testis and inhibit spermatogenesis, but the precise mechanism is yet to be elucidated. This study shows that TOCP inhibited viability of rat spermatogonial stem cells in a dose-dependent manner. TOCP could not lead to cell cycle arrest in the cells; the mRNA levels of p21, p27, p53, and cyclin D1 in the cells were also not affected by TOCP. Meanwhile, TOCP did not induce apoptosis of rat spermatogonial stem cells. After treatment with TOCP, however, both LC3-II and the ratio of LC3-II/LC3-I were markedly increased; autophagy proteins ATG5 and beclin 1 were also increased after treatment with TOCP, indicating that TOCP could induce autophagy in the cells. Ultrastructural observation under the transmission electron microscopy indicated that autophagic vesicles in the cytoplasm containing extensively degraded organelles such as mitochondria and endoplasmic reticulum increased significantly after the cells were treated with TOCP. In summary, we have shown that TOCP can inhibit viability of rat spermatogonial stem cells and induce autophagy of the cells, without affecting cell cycle and apoptosis.

Free access

Li-Juan Xiao, Jin-Xiang Yuan, Xin-Xin Song, Yin-Chuan Li, Zhao-Yuan Hu and Yi-Xun Liu

Stanniocalcin-1 (STC-1) is a recently discovered polypeptide hormone, while stanniocalcin-2 (STC-2) is a subsequently identified homologue of stanniocalcin-1. Although previous studies have shown that both STC-1 and -2 are involved in various physiological processes, such as ion transport, reproduction and development, their expression in the uterus and roles in implantation and early pregnancy are unclear. Here we have investigated the expression and regulation of both STC-1 and STC-2 in rat uterus during early pregnancy under various physiological conditions. We show that only basal levels of STC-1 and STC-2 mRNA were detected in the uterus from day one (D1) to day five (D5) of pregnancy. STC-2 immunostaining was gradually increased in the glandular epithelium from day two (D2), with a peak occurring on D5. High levels of both STC-1 and STC-2 mRNA were observed in the stoma cells at the implantation site on day six (D6) of pregnancy, whereas their immunostaining signals were also significant in the luminal epithelium. Basal levels of both STC-1 and STC-2 mRNA and STC-1 immunostaining were detected in the uterus with delayed implantation. After the delayed implantation was terminated by estrogen treatment, both STC-1 and STC-2 mRNA signals were significantly induced in the stroma underlying the luminal epithelium at the implantation site, and STC-2 immunostaining was also observed in the luminal epithelium surrounding the implanting blastocyst. Embryo transfer experiments further confirmed that STC-1 and STC-2 expression at the implantation sites was induced by the implanting blastocyst. Both STC-1 mRNA and immunostaining were seen in the decidualized cells from day seven (D7) to day nine (D9) of pregnancy. STC-2 mRNA was also found in the whole decidua from D7 to D9 of pregnancy; STC-2 protein, however, was strictly localized to the primary deciduas on D7 and D8, with a weak expression in the whole deciduas on D9. Consistent with the normal pregnancy process, strong STC-1 and STC-2 mRNA signals were detected in the decidualized cells under artificial decidualization, whereas only basal levels of STC-1 mRNA and immunostaining were observed in the control horn. These data suggest, for the first time, that STC-1 together with STC-2 may play important roles in the processes of implantation and decidualization in the rat.

Free access

Li-Juan Xiao, Jin-Xiang Yuan, Yin-Chuan Li, Rui Wang, Zhao-Yuan Hu and Yi-Xun Liu

The extracellular Ca2+-sensing receptor (CaR) is a member of the superfamily of G protein-coupled receptors (GPCRs). It is an important mediator of a wide range of Ca2+-dependent physiological responses in various tissues. In reproductive tissues it has been reported to play a significant role in promoting or maintaining placentation. Meanwhile, another Ca2+ regulated gene stanniocalcin-1 (STC-1) has been documented to be involved in decidualization and uterine remodelling. The phenomenon that CaR mediates STC-1’s transcription responding to extracellular calcium in fish urges us to suppose that CaR, like STC-1, may also play a role in implantation and decidualization. To resolve this conjecture, we have examined the expression and hormonal regulation of the CaR gene in rat uterus during peri-implantation period.

CaR mRNA was expressed at a moderate level in the luminal epithelium of the early stage of pregnancy (from day 1 to day 3). From day 2–3 it began to be expressed more strongly in the stromal cells immediately underneath the luminal epithelium, but decreased to a basal level on day 4. From day 6 to day 9 continuously, both CaR mRNA and protein were highly expressed in the primary decidua. Expression of CaR mRNA and protein in these cells was also observed when a delayed implantation was terminated by estrogen treatment to allow the embryo implantation. In contrast, only basal level expression of the molecules was detected in the cells of animals subjected to a normal-delayed implantation or the pseudopregnant condition.

Embryo transplantation experiment confirmed that CaR expression at the implantation site was induced by the implanting blastocyst. Consistent with the normal pregnant process, CaR mRNA and protein in the cells were also induced by an artificial decidualization procedure. Further experiments demonstrated that treatment of the ovariectomized rat with estrogen or/and progesterone stimulated a high level expression of CaR mRNA in the uterine epithelial and glandular epithelium. In conclusion, CaR was specifically induced during the processes of implantation and subsequent decidualization and may play a role in these processes.

Free access

Xia Wang, Jason E Swain, Mathieu Bollen, Xiao-Tie Liu, Dana A Ohl and Gary D Smith

Reversible phosphorylation, involving protein kinases and phosphatases (PP), is important in regulating oocyte meiosis. Okadaic acid (OA) inhibition of PP1 and/or PP2A stimulates oocyte germinal vesicle breakdown (GVB). In oocytes, PP1 is localized in the cytoplasm and nucleus, yet endogenous regulation of oocyte PP1 has not been investigated. The objectives of the study were to identify intra-oocyte mechanisms regulating PP1 during acquisition of OA-sensitive meiotic competence and meiotic resumption. Immunohistochemical studies revealed that GVB-incompetent oocytes contained equivalent cytoplasmic and nuclear PP1. Upon development of OA-sensitive meiotic competence, PP1 displayed differential intracellular localization with significantly greater nuclear staining with distinct nucleolar rimming compared with cytoplasmic staining. Germinal vesicle-intact oocytes contained neither nuclear inhibitor of PP1, nor PP1 cytoplasmic inhibitor-1 transcripts or proteins. Reverse transcription-PCR with PP1 cytoplasmic inhibitor-2 (I2) primers and oocyte RNA amplified a predicted 330-bp product with the identical sequence to mouse liver I2. Oocytes contained a heat-stable PP1 inhibitor with biochemical properties of I2. Phosphorylation of PP1 at Thr320 by cyclin dependent kinase-1 (CDK1) causes PP1 inactivation. Germinal vesicle-intact oocytes did not contain phospho-Thr320-PP1. Upon GVB, PP1 became phosphorylated at Thr320 and this phosphorylation did not occur if GVB was blocked with the CDK1 inhibitor, roscovitine (ROSC). Inhibition of oocyte GVB with ROSC was reversible and coincided with PP1 phosphorylation at Thr320. Increased oocyte staining of nuclear PP1 compared with cytoplasmic staining at a chronological stage when oocytes gain meiotic competence, and phosphorylation and inhibition of PP1 by CDK1 at or around GVB appear to be important mechanisms in regulating oocyte PP1 activity and meiosis. In addition, these studies provide further support for PP1 being the OA-sensitive PP important in the regulation of the acquisition of meiotic competence, nuclear events during meiotic arrest, and GVB.

Restricted access

Yu-Yin Liu, Yu-Kai Liu, Wen-Ting Hu, Ling-Li Tang, Yan-Ran Sheng, Chun-Yan Wei, Ming-Qing Li and Xiao-Yong Zhu

Endometriosis (EMS) is a chronic inflammatory disease characterized by the presence of extrauterine endometrial tissues. It has been previously reported that the refluxed blood containing viable endometrial tissues and the defective elimination of peritoneal macrophages in the pelvic cavity may involve in EMS pathogenesis. However, the mechanism by which macrophages exhibit attenuated phagocytic capability in EMS remains undetermined. Herein, we found that heme, the byproduct of lysed erythrocytes, accumulated abnormally in the peritoneal fluid (PF) of patients with EMS (14.22 μmol/L, 95% confidence interval (CI): 12.54–16.71), compared with the EMS-free group (9.517 μmol/L, 95% CI: 8.891–10.1053). This abnormal accumulation was not associated with the color of PF, phase of the menstrual cycle or severity of the disease. The reduced phagocytic ability of peritoneal macrophages (pMφs) was observed in the EMS group. Consistently, a high-concentration (30 μmol/L) heme treatment impaired EMS-pMφs phagocytosis more than a low-concentration (10 μmol/L) heme treatment. A similar phenomenon was observed in the EMS-free control pMφs (Ctrl-pMφs) and the CD14+ peripheral monocytes (CD14+ Mos). These results indicated that a high heme concentration exhibits a negative effect on macrophage phagocytosis, which supplements the mechanism of impaired scavenger function of pMφs in EMS.

Free access

Qiao-Song Zheng, Xiao-Na Wang, Qing Wen, Yan Zhang, Su-Ren Chen, Jun Zhang, Xi-Xia Li, Ri-Na Sha, Zhao-Yuan Hu, Fei Gao and Yi-Xun Liu

Spermatogenesis is a complex process involving the regulation of multiple cell types. As the only somatic cell type in the seminiferous tubules, Sertoli cells are essential for spermatogenesis throughout the spermatogenic cycle. The Wilms tumor gene, Wt1, is specifically expressed in the Sertoli cells of the mouse testes. In this study, we demonstrated that Wt1 is required for germ cell differentiation in the developing mouse testes. At 10 days post partum, Wt1-deficient testes exhibited clear meiotic arrest and undifferentiated spermatogonia accumulation in the seminiferous tubules. In addition, the expression of claudin11, a marker and indispensable component of Sertoli cell integrity, was impaired in Wt1 −/flox; Cre-ER TM testes. This observation was confirmed in in vitro testis cultures. However, the basal membrane of the seminiferous tubules in Wt1-deficient testes was not affected. Based on these findings, we propose that Sertoli cells' status is affected in Wt1-deficient mice, resulting in spermatogenesis failure.