scholarly journals Melatonin Receptor 2 Promotes Lipid Metabolism of Cumulus-oocyte Complexes via the cAMP/PKA Pathway

Author(s):  
Jun-Xue Jin ◽  
Hong-Di Cui ◽  
Chao-Qian Jiang ◽  
Zi-Cheng Qi ◽  
Ya Bian ◽  
...  

Abstract Background: The importance of the processes of lipogenesis and lipolysis in providing an essential energy source during oocyte maturation is increasingly being recognized. Recent our studies have demonstrated that melatonin up-regulated lipid metabolism during oocyte maturation. Nevertheless, there is still limited information regarding the underlying molecular mechanisms of action of melatonin on lipid metabolism in porcine cumulus-oocyte complexes (COCs). Here, our aim was to investigate the effect of melatonin on COCs, and the melatonin receptor-mediated lipid metabolism signaling pathway.Materials/methods: To determine the melatonin-mediated lipolysis pathway in cumulus cells, COCs were treated with melatonin and the correlated metabolic responses were assessed using melatonin receptor-mediated signaling.Results: The results showed that exposure of COCs to melatonin during in vitro maturation significantly increased cumulus expansion index, blastocyst formation rate and total cell numbers/blastocyst, although nuclear maturation was no significant difference. The levels of proteins MT1, MT2, Gsα, PKA, and lipolysis-related factors (AGTL, HSL, PLIN A+B) were significantly increased by melatonin supplementation, and this effect was inhibited by simultaneous treatment with melatonin antagonists (luzindole or 4P-PDOT), although 4P-PDOT treatment did not completely block the effect of melatonin on MT1. Further, the gene expression patterns reflected their relevant protein levels in cumulus cells. Melatonin-mediated lipolysis could significantly reduce lipid droplets (LDs) numbers and increase fatty acid (FA) production and ATP levels by increasing the β-oxidation-related gene expression in cumulus cells. Simultaneously, melatonin significantly increased the amount of LDs, FAs, ATP, and enhanced the lipid metabolism-related gene expression in oocytes. Finally, the oocyte quality was improved by increasing GDF9, BMP15 and GSH and decreasing ROS levels.Conclusion: These findings revealed that the MT2-mediated cAMP/PKA signaling pathway promotes intracellular lipolysis and FA production in cumulus cells, which provided an essential energy source for COCs development.

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Qiwei Liu ◽  
Liang Kong ◽  
Junhui Zhang ◽  
Qian Xu ◽  
Jingxue Wang ◽  
...  

Polycystic ovary syndrome (PCOS) is a common female endocrine system disease that affects 17.8% of women of reproductive age and leads to infertility, obesity, glucose metabolic disorders, cardiovascular disease, and body-mind problems. However, the etiology of PCOS remains unclear. Follicular growth is disrupted as a result of ovarian hyperandrogenism and distorted intraovarian paracrine signaling in women with PCOS. Microcommunication between oocytes and cumulus cells plays a critical role in folliculogenesis. Gap junction alpha 1 (GJA1) plays a crucial role in the developing follicles by forming communication channels between cumulus cells and oocytes, but this has not yet been reported in women with PCOS. Therefore, we aimed to study the role of GJA1 in the microcommunication between oocytes and cumulus cells in women with PCOS. In our study, cumulus cell-oocyte complexes (COCs) from women were isolated via ultrasound-guided vaginal puncture, and oocytes were selected from COCs and categorized based on 3 oocyte maturation stages. Then, RT-qPCR and immunofluorescence analysis were performed to detect both the gene expression and protein of GJA1 in oocytes from women with and without PCOS. There was no statistically significant difference in age and BMI (body mass index), but patients with PCOS had a higher ratio of basic LH/FSH (luteinizing hormone/follicle-stimulating hormone), androstenedione, and total ovarian volume. The qRT-PCR results showed higher gene expression of GJA1 in oocytes without PCOS at the germinal vesicle (GV) stage compared with that of oocytes from women with PCOS. Immunofluorescence analysis showed that the expression level of GJA1 in oocytes from women with PCOS was very weak compared with that of oocytes from women without PCOS. In conclusion, GJA1 may play a critical role in the development of oogenesis arrest in women with PCOS throughout the oogenesis processes, including oogenesis and oocyte maturation.


iScience ◽  
2021 ◽  
Vol 24 (4) ◽  
pp. 102357
Author(s):  
Brenda Morsey ◽  
Meng Niu ◽  
Shetty Ravi Dyavar ◽  
Courtney V. Fletcher ◽  
Benjamin G. Lamberty ◽  
...  

2021 ◽  
Author(s):  
◽  
Zaramasina Clark

<p>The number of cycles of assisted reproductive technologies (ART) performed increased by ~9.5 % globally between 2008 and 2010. In spite of this, the success rate in terms of delivery was only ~19.0 % (Dyer et al., 2016). This discrepancy between the demand for, and success of, these technologies necessitates the development of tools to improve ART efficiency. To facilitate this, a better understanding of how the microenvironment changes within the developing follicle to culminate in a mature, developmentally-competent oocyte is required. This study employed an in vivo and in vitro ovine model to investigate the relationship between the surrounding microenvironment and oocyte maturation, and in particular, the attainment of oocyte developmental competency and high-quality embryos.  The first objective of this PhD study was to comprehensively investigate the changing microenvironment of in vivo matured, presumptive preovulatory (PPOV) follicles from wild-type (++) and high ovulation rate (OR; I+B+) ewes. The high OR ewes were heterozygous carriers of mutations in BMP15 (I+) and BMPRIB (B+). Functional differences in follicular somatic (granulosa and cumulus) cells between these genotypes, including differential gonadotropin responsiveness of granulosa cells, composition of follicular fluid and gene expression profiles in cumulus cells were evident. These differences emerged as part of a compensatory mechanism by which oocytes from smaller follicles, containing fewer granulosa cells, achieved developmental competency in I+B+ ewes.  The second objective of this PhD study was to develop new approaches for improving current in vitro maturation (IVM) strategies. The first approach utilised in this study focused on developing biomarkers that could be used to improve prediction of developmental competency in oocytes and in vitro produced embryos. This involved interrogating the hypothesis that a combination of molecular and morphokinetic biomarkers would better predict the developmental competency of oocytes and embryos compared to using these biomarkers alone. The second approach utilised in this PhD study tested the effects of modulating IVM conditions to better mimic the follicular microenvironment of a high, compared to a low, OR species on oocyte developmental competency and embryo quality. This involved supplementing IVM media with different ratios of two oocyte-secreted growth factors, i.e. GDF9:BMP15, that were representative of low or high OR species. These approaches demonstrated significant potential and warrant further investigation.  The most significant finding of this study was that despite variances in the surrounding microenvironment during in vivo and in vitro oocyte maturation that culminated in differential gene expression patterns in cumulus cells, and divergent gonadotropin-responsiveness of granulosa cells, the gene expression signatures of developmentally-competent oocytes and the morphokinetics of high-quality embryos were unaltered. This confirms the value of developing such biomarkers for oocyte development competency and embryo quality that remain unaltered despite a changing surrounding environment. Interestingly, simulating the ratio of GDF9:BMP15 that oocytes from high OR species are exposed to during maturation improved developmental competency in oocytes as demonstrated by increased blastocyst rates. Furthermore, this study has demonstrated that combinations of molecular (cumulus cell gene expression) and morphokinetic biomarkers improved the ability to predict developmental competency in oocytes and embryos. Overall, this study revealed novel information regarding the follicular microenvironment during final maturation and identified several novel approaches to improving the efficiency of ART.</p>


2021 ◽  
Author(s):  
Jianyuan Li ◽  
Hui Shi ◽  
Xiaoyu Liu ◽  
Yanwei Wang ◽  
Haiyan Wang ◽  
...  

Abstract I. Background: Peroxiredoxin 6 (Prdx6) is widely expressed in mammalian tissues. Our previous study demonstrated that Prdx6 was expressed in human epididymis and spermatozoa, and the protective role of Prdx6 in human spermatozoa was also reported. In this study, we demonstrate the potential role and mechanism of Prdx6 in human epididymis epithelial cells (HEECs).II. Methods and Results: Western blotting was used to measure expression levels of key proteins in the JAK / STAT signaling pathway. Digital gene expression analysis (DGE) was used to identify gene expression patterns in control HECs and in HECs after Prdx6-RNA interference (P6-RNAi). The DGE analysis identified 589 up-regulated and 314 down-regulated genes (including Prdx6) in Prdx6-RNAi (P6-RNAi) HEECs. Thirteen significantly different pathways were identified between the two groups, with the majority different expressed genes belonging to the CCL, CXCL, IL, and IFIT families. In particular, the expression levels of IL6, IL6ST, and eighteen IFN related genes were significantly increased in the condition of the down-regulated expression of Prdx6. Compared to control HEECs, the expression levels of JAK1, STAT1, phosphorylated JAK1 and STAT1 were significantly increased, while the expression levels of SOCS3 was significantly decreased in P6-RNAi HEECs. The Malondialdehyde (MDA) level and total antioxidant capacity in P6-RNAi HEECs were significantly increased and decreased compared to that of control, respectively. III. Conclusions: We speculated that knockdown of Prdx6 resulted in higher levels of ROS in HEECs, which in turn, activated the JAK1 / STAT1 signaling pathway induced by IL-6 receptor and IFN.


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