Expression of aquaporin 4 in the chicken oviduct following tamoxifen treatment

Effect of tamoxifen treatment on catalase (CAT) and superoxide dismutase (SOD) expression and localization in the hen oviduct

The imbalance between free reactive oxygen species (ROS) generation and removal (e.g., by antioxidative enzymes) leads to the damage of important biomolecules and cells. Earlier studies in hens showed that treatment with tamoxifen (TMX; estrogen receptor inhibitor) modulates oxidative stress and causes the reproductive system regression realized by cell apoptosis. The aim of the present study was, therefore, to examine the expression and immunolocalization of the key enzymatic antioxidants, i.e. catalase (CAT) and superoxide dismutase (SOD), in the chicken oviduct following TMX treatment. Laying hens were treated daily with TMX until a pause in egg-laying occurred and then euthanized on day 8 of the experiment. Quantitative real-time PCR and western blot analyses showed the presence of CAT and SOD transcripts and proteins, respectively, in all oviductal segments, i.e., the infundibulum, magnum, isthmus, shell gland and vagina. In control hens (laying), the mRNA expression of CAT was the highest in the shell gland, lower in the isthmus and the lowest in other oviductal parts, whereas protein expression was the highest in the magnum, lower in the isthmus and the lowest in other segments. The SOD transcript and protein abundances only were lower in the magnum than in other segments. Immunoreactive CAT and SOD products were localized in all layers of the oviductal wall, but the intensity of staining depended on the cell type. TMX treatment affected CAT and SOD expression and the effect of TMX depended on gene, protein, cell type and oviductal part. Generally, CAT expression was elevated, while SOD expression was decreased under TMX treatment. These results point to the importance of CAT and SOD in the maintenance of proper oviduct health and function. Changes in ROS scavenging enzymes after estrogen receptor blockage indicate the significance of estrogen in the regulation of oxidative status in the avian oviduct.

miRNA-29-3p targets PTEN to regulate follicular development through the PI3K/Akt/mTOR signaling pathway

Granulosa cells play a pivotal role in growth, development and ovulation of ovarian follicle. Simultaneously, autophagy and apoptosis processes are crucial determinants in the destiny of granulosa cells. Within this context, miR-29-3p, known to regulate a broad spectrum of biological processes and critical for tumor detection, prognosis, and treatment, is poised to clarify its roles in both autophagy and apoptosis. To enhance the understanding of the influence of miR-29-3p on follicular development, our study primarily delved into the realms autophagy and apoptosis. We employed a well-established chicken follicular atrophy model achieved through subcutaneous injection of tamoxifen (TMX) into hens. qPCR analysis revealed a significant decrease in the expression of miR-29-3p within the atrophic follicles. In our in vitro experiments with cultured chicken primary granulosa cells, miR-29-3p emerged as a novel microRNA capable of impeding autophagy and apoptosis when transfected with miR-29-3p mimics and inhibitors. Results from luciferase reporter assays corroborated that PTEN is a legitimate target of miR-29-3p. Unlike miR-29-3p, PTEN appeared to foster autophagy and apoptosis in chicken granulosa cells. Moreover, our findings uncovered that miR-29-3p facilitates the phosphorylation of Akt and mTOR proteins by targeting PTEN in chicken granulosa cells. In conclusion, the findings of this study suggest that miR-29-3p, through its targeting of PTEN via the Akt/mTOR signaling pathway, exerts inhibitory effects on autophagy and apoptosis. These effects may hold significant importance in the context of follicular development.

MiR-34a-5p promotes autophagy and apoptosis of ovarian granulosa cells via the Hippo-YAP signaling pathway by targeting LEF1 in chicken

Follicular atresia is a natural physiological phenomenon in poultry reproduction. It is well known that follicular atresia is caused by both autophagy and apoptosis of granulosa cells. In current experiment, we evaluated the function of miR-34a-5p on autophagy and apoptosis in chicken follicular atresia. First, the follicular atresia model of chicken was successfully constructed by subcutaneous injection of tamoxifen (TMX), and found the expression of miR-34a-5p in the atresia follicles obviously increased. Then, we confirmed that miR-34a-5p accelerates autophagy and apoptosis of chicken granulose cells in vitro, and miR-34a-5p could induce apoptosis by mediating autophagy. Mechanistically, lymphoid enhancer binding factor 1 (LEF1) was deemed as a target gene for miR-34a-5p. On the contrary, LEF1 overexpression attenuated the autophagy and apoptosis of chicken granular cells. In addition, it was confirmed that the miR-34a-5p/LEF1 axis plays a regulatory role in chicken granulosa cells by mediating the Hippo-YAP signaling pathway. Taken together, this study demonstrated that miR-34a-5p contributes to autophagy and apoptosis of chicken follicular granulosa cells by targeting LEF1 to mediate the Hippo-YAP signaling pathway.

Changes in Aquaporin 1, 5 and 9 Gene Expression in the Porcine Oviduct According to Estrous Cycle and Early Pregnancy

Aquaporins (AQPs) are a group of small, integral membrane proteins which play an important role in fluid homeostasis in the reproductive system. In our previous study, we demonstrated AQP1, 5 and 9 protein expression and localization in the porcine oviduct. The presence of these isoforms could suggest their role in the transport of the ovum to the uterus by influencing the epithelial cells’ production of oviductal fluid. The aim of this study was to evaluate the expression of AQP1, AQP5 and AQP9 in the infundibulum, ampulla and isthmus in the porcine oviduct during the estrous cycle (early luteal phase, days 2–4, medium luteal phase, days 10–12, late luteal phase days 14–16, follicular phase days 18–20) and pregnancy (period before implantation, days 14–16 and after the implantation, days 30–32) using the Real-Time PCR technique. As clearly demonstrated for the first time, AQP1, 5, and 9 gene expression is influenced by the estrus cycle and pregnancy. Furthermore, expression of AQPs in the porcine oviduct may provide the physiological medium that sustains and enhances fertilization and early cleavage-stage embryonic development. Overall, our study provides a characterization of oviduct AQPs, increasing our understanding of fluid homeostasis in the porcine oviduct to successfully establish and maintain pregnancy.

Tamoxifen-induced alterations in the expression of selected matrix metalloproteinases (MMP-2, -9, -10, and -13) and their tissue inhibitors (TIMP-2 and -3) in the chicken ovary

Matrix metalloproteinases (MMPs) are a family of peptidases that disintegrate extracellular matrix (ECM) molecules associated with tissue remodeling, including reproductive tissues. Their actions are largely controlled by specific tissue inhibitors of MMPs (TIMPs). The role and regulation of MMPs in the chicken ovary is largely unknown. The aim of the present study was to examine the effect of tamoxifen (TMX; estrogen receptor modulator) treatment on the expression of selected members of the MMP system in the laying hen ovary. The activity of MMP-2 and -9 was also examined. Real-time polymerase chain reaction and western blot analyses revealed changes in mRNA and/or protein expression of MMP-2, -9, -10, -13, TIMP-2, and TIMP-3 in the following ovarian follicles after TMX treatment: white (WF), yellowish (YF), small yellow (SYF), and the largest yellow preovulatory (F3-F1). The response to TMX depended on the stage of follicle development and the layer of follicular wall. Moreover, ovarian regression following TMX treatment was accompanied by both an increase in total activity of MMP-2 in the theca layer of F3-F2 and granulosa layer of F2, and a decrease in total activity of MMP-2 in the WF, YF, and SYF, and MMP-9 in theca of F3-F1. In conclusion, the TMX-induced changes in MMP-2, -9, -10, and -13, and TIMP-2 and -3 mRNA expression, as well as MMP-2 and -9 activity, were dependent on tissue and the stage of follicular maturation. Our findings strongly suggests a role for estrogen in regulating the transcription, translation, and/or posttranslational activity of members of the MMP system. Further, these components may be involved in the orchestration of ECM turnover and cellular functions during ovary regression, which occur under conditions of reduced estrogenic activity.