Increased risk of polycystic ovary syndrome (PCOS) associated with CC genotype of miR-146a gene variation

Genetic variants in miR-146a and miR-196a2 in endometriosis: a Brazilian study

OBJECTIVE

The aim of this study was to determine the allelic and genotypic frequencies of the polymorphisms, rs2910164 miR-146a and rs11614913 miR-196a2, by investigating their association with endometriosis.

METHODS

This is a case-control study performed with approximately 120 women. The polymorphisms were determined by real-time polymerase chain reaction. For the statistical analysis, the chi-square and logistic regression tests were used.

RESULTS

There were no significant differences in the genotype and allele frequencies of rs2910164 and rs11614913 between cases and controls. The frequencies in both polymorphisms are in accordance with Hardy-Weinberg equilibrium regarding miR-146a (patients: χ2=1.64, p=0.20; controls: χ2=0.25, p=0.62) and miR-196a2 (patients: χ2=0.58, p=0.44; controls: χ2=2.78, p=0.10). No relationship was observed between rs2910164 and rs11614913 and endometriosis in the inheritance models analyzed.

CONCLUSION

In this study, our results show that the studied polymorphisms are not implicated in the development of endometriosis.

A glance into the roles of microRNAs (exosomal and non-exosomal) in polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder in women of reproductive age. The clinical symptoms include hyperandrogenism, chronic anovulation, and multiple ovarian cysts. PCOS is strongly associated with obesity and insulin resistance. MicroRNAs (miRNAs) are a group of short non-coding RNAs that play a role in the post-transcriptional regulation of gene expression and translational inhibition. They play a vital role in the regulation of multiple metabolic and hormonal processes as well as in oocyte maturation and folliculogenesis in the female reproductive system. miRNAs can be used as diagnostic biomarkers or therapeutic targets because of their stability. The encapsulation of miRNAs in extracellular vesicles or exosomes contributes to their stability. Exosomes are constantly secreted by many cells and size of about 30 to 150 nm. Enveloping miRNAs exosomes can release them for cellular communication. The induced transfer of miRNAs by exosomes is a novel process of genetic exchange between cells. Many studies have shown that along with non-exosomal miRNAs, different types of exosomal miRNAs derived from the serum and follicular fluid can play an essential role in PCOS pathogenesis. These miRNAs are involved in follicular development and various functions in granulosa cells, apoptosis, cell proliferation, and follicular atresia. The present study aimed to comprehensively review the evidence on miRNAs and their affected pathways under both non-exosomal and exosomal circumstances, primarily focusing on the pathogenesis of PCOS.

MIR146A and ADIPOQ genetic variants are associated with birth weight in relation to gestational age: a cohort study

PURPOSE

To evaluate the genetic variants related to polycystic ovary syndrome (PCOS) and its metabolic complications in girls born small for gestational age (SGA).

DESIGN

Retrospective birth cohort study.

MATERIALS AND METHODS

We evaluated 66 women of reproductive age born at term (37-42 weeks of gestational age) according to the birth weight in relation to gestational age: 26 SGA and 40 AGA (Adequate for gestational age). Anthropometric and biochemical characteristics were measured, as well as the PCOS prevalence. We analyzed 48 single nucleotide polymorphisms (SNPs) previously associated with PCOS and its comorbidities using TaqMan Low-Density Array (TLDA). miRNet and STRING databases were used to predict target and disease networks.

RESULTS

Anthropometric and biochemical characteristics did not differ between the SGA and AGA groups, as well as insulin resistance and PCOS prevalence. Two SNPs were not in Hardy-Weinberg equilibrium, the rs2910164 (MIR146A C > G) and rs182052 (ADIPOQ G > A). The rs2910164 minor allele frequency (MAF) was increased in SGA (OR, 2.77; 95%; CI, 1.22-6.29), while the rs182052 was increased AGA (OR, 0.34; 95%; CI, 0.13 - 0.88). The alleles related to reduced miRNA-146a (C) and ADIPOQ (A) activity showed increased frequency in SGA. The mature miR-146a targets 319 genes, been the CXCR4, TMEM167A and IF144L common targets and contributes to PCOS. The ADIPOQ main protein interactions were ERP44, PPARGCIA and CDH13.

CONCLUSIONS

The miR-146a (rs2910164) and ADIPOQ (rs182052) allelic variants are related to birth weight in SGA and may predict health-related outcomes, such as PCOS and obesity risk.

The Translational Role of miRNA in Polycystic Ovary Syndrome: From Bench to Bedside—A Systematic Literature Review

MicroRNAs (miRNAs) are small, non-coding RNAs that are essential for the regulation of post-transcriptional gene expression during tissue development and differentiation. They are involved in the regulation of manifold metabolic and hormonal processes and, within the female reproductive tract, in oocyte maturation and folliculogenesis. Altered miRNA levels have been observed in oncological and inflammatory diseases, diabetes or polycystic ovary syndrome (PCOS). Therefore, miRNAs are proving to be promising potential biomarkers. In women with PCOS, circulating miRNAs can be obtained from whole blood, serum, plasma, urine, and follicular fluid. Our systematic review summarizes data from 2010–2021 on miRNA expression in granulosa and theca cells; the relationship between miRNAs, hormonal changes, glucose and lipid metabolism in women with PCOS; and the potential role of altered miRNAs in fertility (oocyte quality) in PCOS. Furthermore, we discuss miRNAs as a potential therapeutic target in PCOS and as a diagnostic marker for PCOS.

Genetic Variants miR-126, miR-146a, miR-196a2, and miR-499 in Polycystic Ovary Syndrome

Introduction: Alterations in certain microRNAs (miRNAs) and their target genes have reported in polycystic ovary syndrome (PCOS) and other disease of the female reproductive system, and so may be potential biomarkers. We hypothesised alterations in the prevalence of four miRNAs single nucleotide polymorphism (SNP) variants miR-126 rs4636297, miR-146a rs2910164, miR-196a2 rs11614913, and miR-499 rs3746444 in women with PCOS in comparison to healthy controls.

Methods: SNPs in the four miRNAs were determined in 385 patients and 385 controls by standard RT-PCR techniques.

Results: SNPs in miR-126 and miR-246a were significant linked with PCOS under the allelic, dominant, co-dominant, and recessive models (all p ≤ 0.01). The SNP in miR-499 was linked to PCOS in allelic (T, p = 0.002), dominant (p = 0.035) and recessive (p = 0.003) models. The SNPs -196a was significant linked to PCOS only in the recessive model (p = 0.037). Combining these SNPs in miR-499, mi146a, miR-196a and miR-126 respectively into allele haplotypes found highly significant odds ratios (95% CI) of 0.40 (0.29–0.54) (p < 0.001) for the C-G-C-G haplotype, and 0.46 (0.30–0.70) (p = 0.002) for the C-C-C-A haplotype (p = 0.002) for PCOS.

Conclusion: Single SNPs and haplotype combinations in certain SNPs in miR-126, miR-146a, miR-196a2 and miR-499 are strongly linked to PCOS, and so may be useful predictors of this condition.

microRNAs and long non-coding RNAs as biomarkers for polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is known as the most common metabolic/endocrine disorder among women of reproductive age. Its complicated causality assessment and diagnostic emphasized the role of non‐coding regulatory RNAs as molecular biomarkers in studying, diagnosing and even as therapeutics of PCOS. This review discusses a comparative summary of research into microRNAs (miRNAs) and long non‐coding RNAs (lncRNAs) that are molecularly or statistically related to PCOS. We categorize the literature in terms of centering on either miRNAs or lncRNAs and discuss the combinatory studies and promising ideas as well. Additionally, we compare the pros and cons of the prominent research methodologies used for each of the abovementioned research themes and discuss how errors can be stopped from propagation by selecting correct methodologies for future research. Finally, it can be concluded that research into miRNAs and lncRNAs has the potential for identifying functional networks of regulation with multiple mRNAs (and hence, functional proteins). This new understanding may eventually afford clinicians to control the molecular course of the pathogenesis better. With further research, RNA (with statistical significance and present in the blood) may be used as biomarkers for the disease, and more possibilities for RNA therapy agents can be identified.

Non-coding RNAs in polycystic ovary syndrome: a systematic review and meta-analysis

BACKGROUND

Genetic, environmental and epigenetical factors may play important roles in the pathogenesis of polycystic ovary syndrome (PCOS), however the etiology of PCOS remains unclear. Studies indicated that non-coding RNAs (ncRNAs) were involved in the occurrence and development of PCOS. Thus, we aim to perform a systematic review and meta-analysis to investigate the presence and dysregulated expression of ncRNAs in human PCOS.

METHODS

We searched in PubMed, Medline, Web of Science and Embase until July 2019 and summarized all eligible publications focusing on microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and small interfering RNAs (siRNAs) in PCOS.

RESULTS

Sixty-seven articles were included in our systematic review and 9 articles were included in meta-analysis. There is little overlap between studies when comparing miRNA profiles. Sensitivity analysis showed that the expression of miR-93 was upregulated in PCOS patients (WMD 0.75, P < 0.00001), without heterogeneity among remaining studies (I2 = 0%).

CONCLUSION

A large number of ncRNAs with altered levels were observed in plasma, serum, follicular fluid, granulosa cells or other issues from PCOS patients. Aberrant ncRNAs expression in PCOS may lead to aberrant steroidogenesis, adipocyte dysfunction, altered ovarian cell proliferation and/or apoptosis and have the potential to be used as diagnostic biomarkers.

Genetic polymorphisms associated with polycystic ovary syndrome among Iranian women

Polycystic ovary syndrome (PCOS) involves abnormalities in ovarian, reproductive, and metabolic systems. Genetic polymorphisms associated with individual differences and variations might be related to complex disorders with unknown causes, including PCOS. Several leading genetic markers with known cellular functions have been identified among Iranian women presenting with PCOS. In particular, the existing evidence shows a significant relationship between PCOS and the following genetic polymorphisms: rs2275913 (interleukin-17A), rs9927163 (interleukin-32), Pro12Ala (peroxisome proliferator-activated receptor-γ), rs17173608 (chemerin), rs2236242 (vaspin), ApaI (vitamin D receptor), and rs7895833 (sirtuin 1). In addition, a higher risk of PCOS is associated with the rs2910164 (microRNA 146a), rs2241766 (adiponectin), -34 T/C (cytochrome 17), and rs1800682 (Fas) polymorphisms. Furthermore, protective effects against PCOS have been reported for the A4223C polymorphism of adenosine deaminase 1. Overall, the available data indicate that Iranian women with PCOS have a higher prevalence of polymorphisms in inflammation- and metabolism-related genes, but not in insulin-related genes. More extensive studies are needed to identify the ethnicity-related genetic associations in PCOS.