ATP synthase β-subunit abnormality in pancreas islets of rats with polycystic ovary syndrome and type 2 diabetes mellitus

Expression profile analysis of LncRNAs and mRNAs in pre-receptive endometrium of women with polycystic ovary syndrome undergoing in vitro fertilization-embryo transfer

BACKGROUND

To compare the expression levels of long non-coding RNA (lncRNA) and messenger RNA (mRNA) in pre-receptive endometrium between patients with Polycystic Ovary Syndrome (PCOS)and normal ovulation undergoing in vitro fertilization-embryo transfer (IVF-ET).

METHODS

Endometrial tissues were collected with endometrial vacuum curette in pre-receptive phase (3 days after oocytes retrieval) from PCOS and control groups. LncRNAs and mRNAs of endometrium were identified via RNA sequencing and alignments. A subset of 9 differentially expressed lncRNAs and 11 mRNAs were validated by quantitative reverse transcription polymerase chain reaction(qRT-PCR)in 22 PCOS patients and 18 ovulation patients. The function of mRNAs with differential expression patterns were explored using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG).

RESULTS

We found out 687 up-regulated and 680 down-regulated mRNAs, as well as 345 up-regulated and 63 down-regulated lncRNAs in the PCOS patients in contrast to normal ovulation patients. qRT-PCR was used to detect the expression of 11 mRNAs, and validated that the expression of these 6 mRNAs CXCR4, RABL6, OPN3, SYBU, IDH1, NOP10 were significantly elevated among PCOS patients, and the expression of ZEB1 was significantly decreased. qRT-PCR was performed to detect the expression of 9 lncRNAs, and validated that the expression of these 7 lncRNAs IDH1-AS1, PCAT14, FTX, DANCR, PRKCQ-AS1, SNHG8, TPT1-AS1 were significantly enhanced among PCOS patients. Bioinformatics analysis showed that differentially expressed genes (DEGs) involved KEGG pathway were tyrosine metabolism, PI3K-Akt pathway, metabolic pathway, Jak-STAT pathway, pyruvate metabolism, protein processing in endoplasmic reticulum, oxidative phosphorylation and proteasome. The up-regulation of GO classification was involved in ATP metabolic process, oxidative phosphorylation, RNA catabolic process, and down-regulation of GO classification was response to corticosteroid, steroid hormone, and T cell activation.

CONCLUSION

Our results determined the characteristics and expression profile of endometrial lncRNAs and mRNAs in PCOS patients in pre-receptive phase, which is the day 3 after oocytes retrival. The possible pathways and related genes of endometrial receptivity disorders were found, and those lncRNAs may be developed as a predictive biomarker of endometrium in pre-receptive phase.

Mitochondrial Dysfunction in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common female reproductive metabolisms. It is an endocrine disease that affects reproductive women and often exhibits with hyperandrogenemia, insulin resistance (IR), low inflammation, and an increased risk of type 2 diabetes mellitus, metabolic syndrome, and cardiovascular events such as hypertension and dyslipidemia in patients. However, the molecular mechanism of PCOS is still unclear. Recently, an increasing number of studies have shown that the oxidative stress induced by mitochondrial dysfunction has negative effects on IR, lipid metabolism, and follicular development, suggesting that mitochondrial dysfunction plays an essential role in the development of PCOS. Abnormal mitochondrial DNA copy number in patients with PCOS, and mitochondrial gene mutations, has been the focus of research in recent years, and functional mitochondrial diseases have been gradually accepted as a related factor in PCOS. This review is intended to summarize and discuss previous and recent studies and findings on the connections between mitochondrial dysfunction and PCOS.

Mitochondrial dysfunction: An emerging link in the pathophysiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder characterized by irregular menstrual cycles, hyperandrogenism and subfertility. Due to its complex manifestation, the pathogenic mechanism of PCOS is not well defined. Cumulative effect of altered genetic and epigenetic factors along with environmental factors may play a role in the manifestation of PCOS leading to systemic malfunction. With failure of genome-wide association study (GWAS) and other studies performed on nuclear genome to provide any clue for precise mechanism of PCOS pathogenesis, attention has been diverted to mitochondria. Mitochondrion plays an important role in cellular metabolic functions and is linked to Insulin Resistance (IR). Recently, increasing reports suggest that mitochondrial dysfunction may be a contributing factor in the pathogenesis of PCOS. Hence, in this review, we have discussed mitochondrial biology in brief and emphasizes on genetic and epigenetic aspects of mitochondrial dysfunction studied in PCOS women and PCOS-like animal models. We also highlight underlying mechanism behind mitochondrial dysfunction contributing to PCOS and its related complications such as obesity, diabetes, cardiovascular diseases, metabolic syndrome, non-alcoholic fatty liver disease (NAFLD) and cancer. Furthermore, contrasting remarks against involvement of mitochondrial dysfunction in PCOS pathophysiology have also been presented. This review enhances our understanding in relation to mitochondrial dysfunction in the etiology of PCOS and stimulates further research to explore a clear link between mitochondrial dysfunction and PCOS pathogenesis and progression. Understanding pathogenic mechanisms underlying PCOS will open new windows to develop promising therapeutic strategies against PCOS.

Abnormal expression of HSP70 may contribute to PCOS pathology

Background

The mechanism of the pathological change of polycystic ovary syndrome (PCOS) is still unclear. Previous studies have shown that PCOS is a chronic nonspecific low-grade inflammatory condition, and that heat shock protein (HSP)70 has a potent anti-inflammatory property. So the aim of this study is to investigate the correlation between HSP70 and the hormones and inflammatory factors and to find out the role of HSP70 in the pathogenesis of PCOS.

Methods

Twenty female Sprague–Dawley (SD) rats (aged 23 days and weighted 80-90 g) were randomly divided into two groups (n = 10 per group), PCOS group and control group. PCOS group were subcutaneously injected with 6 mg/100 g dehydro-epiandrosterone (DHEA) for 20 consecutive days, the control group were subcutaneously injected with a solvent of equivalent amount. All the samples were collected in the morning fasting state, 12 h after the last administration. Histological examinations of ovarian tissues were analyzed. Hormone levels and inflammatory factors levels were measured by enzyme-linked immunosorbent assay (ELISA) kits.

Results

Serum concentrations of testosterone (T) and luteinizing hormone (LH) were significantly higher in the PCOS group than the control group (P < 0.001), but the concentrations of estradiol (E₂), follicle stimulating hormone (FSH) and insulin didn’t show significant difference between these two groups. All the concentrations of inflammatory factors including C-reactive protein (CRP), interleukin (IL)-6, IL-18, and tumor necrosis factor (TNF)-α. were significantly higher in PCOS group than the control group (P < 0.001). The expressions of HSP70 were significantly lower in serum but higher in ovarian tissues in the PCOS group than the control group. Spearman rank correlation analysis showed strong negative correlation of serum HSP70 levels with T, LH and all the detected inflammatory factors.

Conclusion

The abnormal expression of HSP70 correlated with testosterone and inflammatory factors, which indicates that HSP70 may play an important role in PCOS pathology.