Estradiol-17ß regulates proliferation and apoptosis of sheep endometrial epithelial cells by regulating the relative abundance of YAP1.

Yes-associated protein 1 (YAP1) transcription regulator of the Hippo protein kinase pathway, serves as a key regulator of tissue growth and organ size by regulating cell proliferation and apoptosis. Effects of YAP1 on proliferation and apoptosis of sheep endometrial epithelial cells (EEC) as a result of estradiol-17ß (E2) treatment, however, remain unclear. In the present study, the abundance of YAP1 protein in the uterine horn was greater than that in the uterine body or cervix. The YAP1 protein was primarily localized in the endometrial luminal and glandular epithelial cells of the uterine horn of ewes on day 2 of the estrous cycle. Compared with control samples, there was a lesser abundance of YAP1 mRNA transcript that was associated with a lesser proliferation and greater apoptosis of EEC. There were also lesser concentrations of epidermal growth factor and insulin-like growth factor 1 in the spent culture medium when there was a lesser abundance of YAP1 mRNA in EEC compared with those in the control group. When there was a greater abundance of YAP1 mRNA transcript, there were greater concentrations of epidermal growth factor and insulin-like growth factor 1 in the spent media. Furthermore, with estradiol-17ß treatment the abundance of YAP1 mRNA transcript was similar to that of the control samples. Taken together, estradiol-17ß may function as an essential regulator of EEC proliferation and apoptosis by modulation of concentrations of YAP1 protein in the sheep uterus. These results indicate there are molecular mechanisms of estradiol-17ß and YAP1 in EEC proliferation and apoptosis of ewes.

Effects of l-arginine on endometrial estrogen receptor α/ß and progesterone receptor expression in nutrient-restricted sheep.

This study aimed to determine the effects of l-arginine (L-Arg) supplementation on steroid hormone receptors in non-pregnant ovine endometrium. All experimental ewes were randomly assigned to either a control group (n = 6), a nutrient-restricted group (n = 6), or an L-Arg supplemented nutrient-restricted group (n = 6). The effects of L-Arg on estrogen receptor α/ß (ERα/ß) and progesterone receptor (PGR) expression in the ovine endometrium were assessed. Our results showed that levels of ERß and PGR expression were significantly increased by nutrient restriction, but L-Arg counteracted the effect of nutrient restriction on ERß and PGR expression (p < 0.05). Also, expression of endometrial ERα was substantially increased (p < 0.05) by L-Arg supplementation. Furthermore, ERα/ß and PGR were mainly detected in the endometrial luminal epithelium and glandular epithelium. Therefore, we isolated and identified endometrial epithelial cells (EECs) from sheep. Different concentrations of L-Arg were added to investigate the effects on ERα/ß and PGR in EECs. The expression levels of endothelial nitric oxide synthase, ERß, and PGR were significantly increased in response to low-concentration (200 µmol) L-Arg supplementation, which subsequently decreased with a high concentration (800 µmol) (p < 0.05). Otherwise, ERα expression was remarkably increased at both L-Arg concentrations in EECs (p < 0.05). Overall, the results indicated that L-Arg performed crucial roles in the regulation of ovine steroid hormone receptor expression in the endometrium. The results of this study provide a theoretical basis and technical means for the normal function of endometrium in response to low nutrient levels.

Effects of nutrient restriction and arginine treatment on oxidative stress in the ovarian tissue of ewes during the luteal phase.

The aim of this study was to determine whether nutrient restriction and arginine treatment affect energy metabolism changes and oxidative stress through the mitochondrial pathway in the ovarian tissue of ewes during the luteal phase. On days 6-15 of the estrous cycle, 24 multiparous Hu sheep (BW = 43.56 ±â€¯1.53 kg) were randomly assigned to three groups: control group (CG; n = 6), restriction group (RG; n = 9), and l-arginine group (AG; n = 9) administered Arg treatment (or vehicle) three times per day. The ewes were slaughtered at the end of treatment, and blood samples and ovaries were collected for analysis. In this study, the expression levels of antioxidase enzymes (SOD2, CAT and GPX1) and mitochondrial biogenesis-related genes (ESRRA and TFAM), as well as antioxidase activity and mitochondrial function were examined in ovarian tissue. Nutrient restriction resulted in activation of ESRRA and TFAM and an increase in relative mtDNA copy number, whereas arginine treatment led to a pronounced recovery of ovarian tissue. In addition, we observed increased AMPK phosphorylation at Thr172 and SIRT3 levels in nutrient restricted ewes, and these effects decreased with arginine treatment. In conclusion, the present results indicated that short-term nutritional restriction led to changes in energy metabolism and oxidative stress. These changes disrupted the redox balance, thus leading to apoptosis through the mitochondria-dependent apoptosis pathway. Arginine treatment altered gene expression in ovarian tissue and increased the resistance to oxidative stress and the anti-apoptosis capacity. The results presented here suggest a potential method to increase agricultural productivity and economic benefits in the sheep industry by using dietary supplementation with arginine to decrease temporary undernutrition of ewes.