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W M Liu, Y J Cao, Y J Yang, J Li, Z Hu and E-K Duan

The expression of tetraspanin CD9 was found on blastocysts in mice and endometrium epithelial cells in human and bovine. However, it remains unknown how CD9 is involved in the precise dialogue between embryo and uterus during early pregnancy. This study was designed to investigate the functional roles of CD9 in the embryo implantation with monoclonal antibody against CD9 protein (anti-CD9 mAb) and antisense oligonucleotide against CD9 gene (AS-CD9). Our results showed that intrauterine injection of anti-CD9 mAb on day 4 of pregnancy significantly increased the number of embryos implanted (7.24±0.39 versus 4.04±0.38). In vitro, anti-CD9 mAb or AS-CD9 significantly enhanced embryo-outgrowth ability on the monolayer of uterus epithelial cells in a dose-dependent manner. However, the attachment of blastocysts to epithelial cells was unaffected. Furthermore, we found that anti-CD9 mAb or AS-CD9 stimulated matrix metalloproteinase 2 (MMP-2) production of blastocysts on Fibronectin. LY294002, a specific inhibitor of phosphoinositide 3-kinase, was able to counteract the effect of anti-CD9 mAb and AS-CD9 on outgrowth ability and production of MMP-2. Our results indicated that CD9 played a role of inhibiting embryo implantation. CD9 was able to impair embryo invasion and the production of MMP-2 through the phosphoinositide 3-kinase signaling pathway.

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J Bian, X M Bai, Y L Zhao, L Zhang and Z J Liu

Obesity is currently a worldwide pandemic. Leptin resistance is a main mechanism of obese human and rodents. The downregulation of the long form of the leptin receptor (Lrb) was involved in leptin resistance in diet-induced obese rats. In the studies, we investigated whether arcuate nucleus (ARC) silencing of Lrb would promote diet-induced obesity in rats. Lentiviral vectors expressing Lrb-shRNA were administered to 5-week-old male rats by ARC injection. Following viral delivery, the rats were provided with a high-fat diet (HFD) or a chow diet (CD). After 8 weeks of the diet, serum leptin, and insulin concentrations were measured by RIA, gene expression of Lrb in the ARC was detected by a real-time RT-PCR, and leptin signaling was examined by western blot. The Lrb-shRNA knocked down the expression of Lrb mRNA in infected regions by 54% for the HFD rats and 47% for the CD rats respectively. The Lrb knockdown reduced Stats3 activation and increased expression of Npy mRNA. The rats with reduced Lrb in the ARC showed a significant increase in energy intake and body weight (BW) again when fed with a HFD. By contrast, there were no effects of Lrb reduction on energy intake or BW when rats maintained on a low-fat chow. Our results provide evidence that Lrb knockdown selectively in the ARC promotes diet-induced obesity and associated metabolic complications in rats.

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FY Diao, M Xu, Y Hu, J Li, Z Xu, M Lin, L Wang, Y Zhou, Z Zhou, J Liu and J Sha

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders; it is characterized by polycystic ovaries, hyperandrogenism and chronic anovulation. To obtain a global view of those genes that might be involved in the development of this complex clinical disorder, we used recently developed cDNA microarray technology to compare differential gene expressions between normal human ovary and ovaries from PCOS patients. A total of 9216 clones randomly selected from a commercial human ovary cDNA library were screened. Among them, 290 clones showed differential expressions, including 119 known genes and 100 known or unknown expressed sequence tags (ESTs). Among 119 known genes, 88 were upregulated and 31 downregulated in the PCOS ovary, as compared with normal human ovary. These differentially expressed genes are involved in various biologic functions, such as cell division/apoptosis, regulation of gene expression and metabolism, reflecting the complexity of clinical manifestations of PCOS. The molecular characteristics established from our study will further our understanding of the pathogenesis of PCOS and help us to identify new targets for further studies and for the development of new therapeutic interventions.

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C-L Hsieh, Z Xie, Z-Y Liu, J E Green, W D Martin, M W Datta, F Yeung, D Pan and L W K Chung

Numerous mouse models of prostate carcinogenesis have been developed, but hitherto there has been no model in which the prostate gland could be imaged in live animals. The transgenic model generated here targeted mouse prostate gland using a firefly luciferase enzyme under the control of a small but highly active and specific supra prostate-specific antigen (sPSA) promoter. We evaluated postnatal prostate development, involution and androgen-induced restoration of prostate growth in adult transgenic mice using bioluminescence imaging. Results of our study showed that: (i) the prostate gland of male offspring did not yield a significant bioluminescence signal until after sexual maturity. Luciferase was detected in the luminal epithelial cells of the ventral and dorsolateral lobes of the prostate gland and caput epididymis, with little or no activity in 18 other organs evaluated. (ii) While a constant high level of bioluminescence was detected in the mouse prostate from 5 to 35 weeks of age, a slight drop in bioluminescence was detected at 36 to 54 weeks. (iii) Upon castration, the luciferase activity signal associated with mouse prostate detected by a cooled charge-coupled device camera was dramatically reduced. This signal could be rapidly restored to pre-castration levels after androgen administration. Androgen-induced luciferase activity subsided to nearly basal levels 5 days following the last injection. These data demonstrate that a bioluminescent mouse model with luciferase activity restricted to the prostate gland under the control of a (sPSA) promoter can be used on a real-time basis in live animals to investigate the development and responsiveness of the prostate gland to exogenously administered androgen. This model can be extended to detect the responsiveness of the prostate gland to therapy and used as a founder strain to visualize tumors in hosts with different genetic backgrounds.