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  • Author: Yan Gao x
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Lizhu Ma, Yuxin Zheng, Xiaorong Tang, Huimin Gao, Ning Liu, Yan Gao, Lizhuang Hao, Shujie Liu and Zhongliang Jiang

It is well documented that granulosa cell apoptosis is the main reason for follicular atresia and death, however, increasing evidence suggests that autophagy plays an important role in the fate of granulosa cells. MiR-21-3p regulated many fundamental biological processes and was pivotal in autophagy of tumor cell, nevertheless, the autophagy in cattle ovary and how miR-21-3p regulates the follicular cells is unknown. In this study, we aimed to elucidate the autophagy and the role of miR-21-3p in cattle ovary using bovine primary ovarian granulosa cells (BGCs). The results showed the autophagy for the first time in BGCs in large follicle according to autophagic gene transcript of LC3, BECN-1, ATG3, protein expression of LC3, P62 and LC3 puncta, a standard marker for autophagosomes. MiR-21-3p was identified as a novel miRNA that repressed BGCs autophagy according to the results from plasmids transfection of miR-21-3p mimics and inhibitor. Meanwhile, VEGFA was confirmed to be a validated target of miR-21-3p in BGCs using luciferase reporter assays and the results of VEGFA expression decreased with transfection of miR-21-3p mimics, while increased with transfection of miR-21-3p inhibitor. In addition, small interference mediated knockdown of VEGFA significantly inhibits BGCs autophagy signaling, however, overexpression of VEGFA in BGCs promoted autophagy in the presence of miR-21-3p. Finally, the results of AKT and it’s phosphorylation suggested that miR-21-3p suppressed VEGFA expression through downregulating AKT phosphorylation signaling. In summary, this study demonstrates that miR-21-3p inhibits BGCs autophagy by targeting VEGFA and attenuating PI3K/AKT signaling.

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Lizhu Ma, Yuxin Zheng, Xiaorong Tang, Huimin Gao, Ning Liu, Yan Gao, Lizhuang Hao, Shujie Liu and Zhongliang Jiang

It is well documented that granulosa cell apoptosis is the main reason for follicular atresia and death; however, increasing evidence suggests that autophagy plays an important role in the fate of granulosa cells. miR-21-3p regulates many fundamental biological processes and is pivotal in the autophagy of tumor cells; nevertheless, the autophagy in cattle ovary and how miR-21-3p regulates the follicular cells is unknown. In this study, we aimed to elucidate the autophagy and the role of miR-21-3p in cattle ovary using bovine primary ovarian granulosa cells (BGCs). The results showed the autophagy for the first time in BGCs in large follicle according to autophagic gene transcript of LC3, BECN-1, ATG3, protein expression of LC3, P62 and LC3 puncta, a standard marker for autophagosomes. miR-21-3p was identified as a novel miRNA that repressed BGCs autophagy according to the results from plasmids transfection of miR-21-3p mimics and inhibitor. Meanwhile, VEGFA was confirmed to be a validated target of miR-21-3p in BGCs using luciferase reporter assays and the results of VEGFA expression decreased with transfection of miR-21-3p mimics, while it increased with transfection of miR-21-3p inhibitor. In addition, small interference-mediated knockdown of VEGFA significantly inhibits BGCs autophagy signaling; however, overexpression of VEGFA in BGCs promoted autophagy in the presence of miR-21-3p. Finally, the results of AKT and its phosphorylation suggested that miR-21-3p suppressed VEGFA expression through downregulating AKT phosphorylation signaling. In summary, this study demonstrates that miR-21-3p inhibits BGCs autophagy by targeting VEGFA and attenuating PI3K/AKT signaling.

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C L Lu, J Yan, X Zhi, X Xia, T R Wang, L Y Yan, Y Yu, T Ding, J M Gao, R Li and J Qiao

Fertility preservation is an important type of frontier scientific research in the field of reproductive health. The culture of ovarian cortices to i) initiate primordial follicle growth and ii) procure developing follicles for later oocyte maturation is a promising fertility preservation strategy, especially for older women or cancer patients. At present, this goal remains largely unsubstantiated in primates because of the difficulty in attaining relatively large follicles via ovarian cortex culture. To overcome this hurdle, we cultured macaque monkey ovarian cortices with FSH, kit ligand (KL), basic fibroblast growth factor (bFGF), and/or epidermal growth factor (EGF). The various factors and factor combinations promoted primordial follicle development to different extents. Notably, both bFF (bFGF, 100 ng/ml and FSH, 50 ng/ml) and KF (KL, 100 ng/ml and FSH, 50 ng/ml) contributed to the activation of primordial follicles at day 12 (D12) of culture, whereas at D18, the proportions of developing follicles were significantly higher in the bFF and KF groups relative to the other treatment groups, particularly in the bFF group. Estradiol and progesterone production were also highest in the bFF group, and primary follicle diameters were the largest. Up until D24, the bFF group still exhibited the highest proportion of developing follicles. In conclusion, the bFGF–FSH combination promotes nonhuman primate primordial follicle development in vitro, with the optimal experimental window within 18 days. These results provide evidence for the future success of human ovarian cortex culture and the eventual acquisition of mature human follicles or oocytes for fertility restoration.

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Ping Zhou, Yan-Guang Wu, Qing Li, Guo-Cheng Lan, Gang Wang, Da Gao and Jing-He Tan

To improve in vitro maturation (IVM) of denuded oocytes (DOs), we observed the interactive effects of cysteamine, cystine and cumulus cells on the glutathione (l-γ-glutamyl-l-cysteinyl-glycine; GSH) level and developmental capacity of goat IVM oocytes. Cysteamine supplementation increased the GSH level and blastocyst rates of both cumulus–oocyte complexes (COCs) and DOs, while the addition of cystine increased the GSH level and blastulation only in the presence of cumulus cells (COCs or DOs co-cultured on a cumulus cell monolayer). Simultaneous supplementation of cysteamine and cystine increased the GSH content and blastulation of co-cultured DOs to a level similar to that of COCs matured without thiol supplementation. Co-culture without thiol supplementation improved DOs' GSH synthesis but not blastulation. The results suggest that DOs cannot utilize cystine for GSH synthesis unless exogenous cysteamine is supplied by either cumulus cells or supplementation. Thus, while the addition of cystine alone is enough to improve IVM of COCs, improvement of DOs requires supplementation of both cystine and cysteamine. Synergic actions between cysteamine, cystine and cumulus cells restore the GSH level and developmental capacity of goat DOs.

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Hua-Yu Lian, Yan Gao, Guang-Zhong Jiao, Ming-Ju Sun, Xiu-Fen Wu, Tian-Yang Wang, Hong Li and Jing-He Tan

In this study, using a mouse model, we tested the hypothesis that restraint stress would impair the developmental potential of oocytes by causing oxidative stress and that antioxidant supplementation could overcome the adverse effect of stress-induced oxidative stress. Female mice were subjected to restraint stress for 24 h starting 24 h after equine chorionic gonadotropin injection. At the end of stress exposure, mice were either killed to recover oocytes for in vitro maturation (IVM) or injected with human chorionic gonadotropin and caged with male mice to observe in vivo development. The effect of antioxidants was tested in vitro by adding them to IVM medium or in vivo by maternal injection immediately before restraint stress exposure. Assays carried out to determine total oxidant and antioxidant status, oxidative stress index, and reactive oxygen species (ROS) and glutathione levels indicated that restraint stress increased oxidative stress in mouse serum, ovaries, and oocytes. Whereas the percentage of blastocysts and number of cells per blastocyst decreased significantly in oocytes from restraint-stressed mice, addition of antioxidants to IVM medium significantly improved their blastocyst development. Supplementation of cystine and cysteamine to IVM medium reduced ROS levels and aneuploidy while increasing glutathione synthesis and improving pre- and postimplantation development of oocytes from restraint-stressed mice. Furthermore, injection of the antioxidant epigallocatechin gallate into restraint-stressed mice significantly improved the blastocyst formation and postimplantation development of their oocytes. In conclusion, restraint stress at the oocyte prematuration stage impaired the developmental potential of oocytes by increasing oxidative stress and addition of antioxidants to IVM medium or maternal antioxidant injection overcame the detrimental effect of stress-induced oxidative stress. The data reported herein are helpful when making attempts to increase the chances of a successful outcome in human IVF, because restraint was applied at a stage similar to the FSH stimulation period in a human IVF program.

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Muyun Wei, Ying Gao, Bingru Lu, Yulian Jiao, Xiaowen Liu, Bin Cui, Shengnan Hu, Linying Sun, Shaowei Mao, Jing Dong, Lei Yan, Zijiang Chen and Yueran Zhao

Defective decidualization of human endometrial stromal cells (ESCs) has recently been highlighted as an underlying cause of implantation failure. FK-506-binding protein 51 (FKBP51) has been shown to participate in the steroid hormone response and the protein kinase B (AKT) regulation process, both of which are important pathways involved in decidualization. The objective of the present study was to investigate the potential effects and mechanisms of FKBP51 in the regulation of ESC decidualization. By performing immunohistochemical staining on an endometrial tissue microarray (TMA) derived from normal females, we found that FKBP51 expression was much higher in the luteal phase than in the follicular phase in ESCs. Primary ESCs were isolated from patients to build an in vitro decidualization model through co-culture with medroxyprogesterone acetate (MPA) and 8-bromoadenosine (cAMP). SC79, a specific AKT activator in various physiological and pathological conditions, and shRNA-FKBP51 were used to examine the roles of AKT and FKBP51 in decidualization. The Western blot and RT-PCR results showed that FKBP51, insulin-like growth factor-binding protein 1 (IGFBP1) and prolactin (PRL) expression increased in ESCs treated with MPA + cAMP; meanwhile, the level of p-Ser473 AKT (p-S473 AKT) decreased and forkhead box protein O1 (FOXO1A) expression increased. Decidualization was inhibited by the AKT activator SC79 and the transfection of FKBP51-shRNA by affecting protein synthesis, cell morphology, cell growth and cell cycle. Furthermore, this inhibition was rescued by FKBP51-cDNA transfection. The results supported that FKBP51 promotes decidualization by reducing the Ser473 phosphorylation levels in AKT.

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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.