lncRNA PVT1/MicroRNA-17-5p/PTEN Axis Regulates Secretion of E2 and P4, Proliferation, and Apoptosis of Ovarian Granulosa Cells in PCOS

Small in Size, but Large in Action: microRNAs as Potential Modulators of PTEN in Breast and Lung Cancers

MicroRNAs (miRNAs) are well-known regulators of biological mechanisms with a small size of 19–24 nucleotides and a single-stranded structure. miRNA dysregulation occurs in cancer progression. miRNAs can function as tumor-suppressing or tumor-promoting factors in cancer via regulating molecular pathways. Breast and lung cancers are two malignant thoracic tumors in which the abnormal expression of miRNAs plays a significant role in their development. Phosphatase and tensin homolog (PTEN) is a tumor-suppressor factor that is capable of suppressing the growth, viability, and metastasis of cancer cells via downregulating phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling. PTEN downregulation occurs in lung and breast cancers to promote PI3K/Akt expression, leading to uncontrolled proliferation, metastasis, and their resistance to chemotherapy and radiotherapy. miRNAs as upstream mediators of PTEN can dually induce/inhibit PTEN signaling in affecting the malignant behavior of lung and breast cancer cells. Furthermore, long non-coding RNAs and circular RNAs can regulate the miRNA/PTEN axis in lung and breast cancer cells. It seems that anti-tumor compounds such as baicalein, propofol, and curcumin can induce PTEN upregulation by affecting miRNAs in suppressing breast and lung cancer progression. These topics are discussed in the current review with a focus on molecular pathways.

lncRNA MALAT1 Regulates Mouse Granulosa Cell Apoptosis and 17β-Estradiol Synthesis via Regulating miR-205/CREB1 Axis

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a known long noncoding RNA, was reported to play a crucial role in follicular growth and ovarian disease. However, the physiological function of MALAT1 in mouse granulosa cells (mGCs) remains largely unclear. The aims of this study were to determine the biological function and molecular mechanism of MALAT1 in mGCs. We knocked down MALAT1 in mGCs by using siRNA against MALAT1. We found that knockdown of MALAT1 promoted apoptosis and caspase-3/9 activities in mGCs. Enzyme-linked immunosorbent assay demonstrated that knockdown of MALAT1 significantly decreased the production of estradiol (E2) and progesterone (P4) in mGCs. Mechanistically, MALAT1 serves as a competing endogenous RNA (ceRNA) to sponge microRNA-205 (miR-205), thereby facilitating its downstream target of cyclic AMP response element- (CRE-) binding protein 1 (CREB1). Furthermore, CREB1 overexpression or miR-205 downregulation partially recovered the effect of MALAT1 depletion in mGCs. In summary, these findings suggested that MALAT1 regulated apoptosis and estradiol synthesis of mGCs through the miR-205/CREB1 axis.

Differential expression and prediction of function of lncRNAs in the ovaries of low and high fecundity Hanper sheep

Litter size is an important trait that determines the production efficiency of sheep bred for meat. Its detailed investigation can reveal the molecular mechanisms that control the fecundity of sheep and possibly accelerate the breeding process of new varieties of sheep that have high prolificacy. Long non-coding RNAs (lncRNAs) have proven to be an important factor in the regulation of follicular development. However, the mechanisms by which lncRNAs regulate litter size in sheep remain unclear. In the present study, ovarian tissues from the follicular (F) or luteal phase (L) of Hanper sheep that were either monotocous (M) or polytocous (P; FM, FP, LM and LP groups) were collected and sequenced to identify differentially expressed lncRNAs and predict their function. The results indicate that the number of up- and down-regulated lncRNAs in the follicular phase (FM vs. FP) was 95 and 111 and 109 and 49, respectively, in the luteal phase (LM vs. LP). The functional enrichment of the different lncRNAs coexpressed with mRNA was analysed. The results demonstrated that the KISS1-GnRH-LH/FSH-E2 and EGF-EGFR-RAS-PI3K signalling pathways promoted the initiation of the primordial period, follicular development and ovulation in the follicular phase (FM vs. FP). During the luteal phase (LM vs. LP), the production and development of the corpus luteum in ewes was influenced by the KITLG-KIT/FGF-FGFR/HGF-MET-RAS-ERK signalling pathway. STEM clustering functional enrichment analysis of the differentially expressed lncRNAs indicated that profile11 was principally enriched in the Cytokine-Jak-STAT, PDGF-PDGFR-PI3K and KITLG-KIT-RAS-ERK signalling pathways. By analysis of the differential expression of the lncRNAs and their expression in each group, lncRNAs Xist (loc101112291) and Gtl2 (loc101123329) were found to be highly expressed, suggesting that regulation of follicular development was mediated through methylation processes.

8q24.21 Locus: A Paradigm to Link Non-Coding RNAs, Genome Polymorphisms and Cancer

The majority of the human genome is comprised of non-protein-coding genes, but the relevance of non-coding RNAs in complex diseases has yet to be fully elucidated. One class of non-coding RNAs is long non-coding RNAs or lncRNAs, many of which have been identified to play a range of roles in transcription and translation. While the clinical importance of the majority of lncRNAs have yet to be identified, it is puzzling that a large number of disease-associated genetic variations are seen in lncRNA genes. The 8q24.21 locus is rich in lncRNAs and very few protein-coding genes are located in this region. Interestingly, the 8q24.21 region is also a hot spot for genetic variants associated with an increased risk of cancer. Research focusing on the lncRNAs in this area of the genome has indicated clinical relevance of lncRNAs in different cancers. In this review, we summarise the lncRNAs in the 8q24.21 region with respect to their role in cancer and discuss the potential impact of cancer-associated genetic polymorphisms on the function of lncRNAs in initiation and progression of cancer.

Long non-coding RNAs: novel players in the pathogenesis of polycystic ovary syndrome

Long non-coding RNAs (lncRNAs) are a class of transcripts (>200 nucleotides) lacking protein-coding capacity. Based on the complex three-dimensional structure, lncRNAs are involved in many biological processes and can regulate the expression of target genes at chromatin modification, transcriptional and post-transcriptional levels. LncRNAs have been studied in multiple diseases but little is known about their role(s) in polycystic ovary syndrome (PCOS), the most common endocrinological disorder in reproductive-aged women around the world. In this review, we characterized and explored the potential mechanisms of lncRNAs in the pathogenesis of PCOS. We found that lncRNAs play a molecular role in PCOS mainly by functioning as the competitive endogenous RNA (ceRNA) and are significantly correlated with some clinical phenotypes. We summarized in detail regarding aberrant lncRNAs in different specimens of women with PCOS [i.e., granulosa cells (GCs), cumulus cells (CCs), follicular fluid (FF), peripheral blood] and various PCOS rodent models [i.e., dehydroepiandrosterone (DHEA) and letrozole induced models]. In clinical practice, detection of lncRNAs in serum might enable early diagnosis. Furthermore, new lncRNA-based classifications might be emerging as potent predictors of a particular phenotype in PCOS. Overall, we proposed new insights for the application of precision medicine approaches to the management of PCOS.

miR-141-3p is Poorly Expressed in Polycystic Ovary Syndrome and Correlates with Glucose and Lipid Metabolism

Polycystic ovary syndrome (PCOS) is a common endocrinopathy with high prevalence. miR-141-3p downregulation was reported in PCOS rats. This study intended to investigate miR-141-3p expression in serum of PCOS patients and its correlation with glucose and lipid metabolism. A total of 100 PCOS patients and 100 healthy controls were enrolled in this study. Clinical parameters and glucose and lipid indexes were analyzed. A 3-month fat reduction intervention was conducted to PCOS-obese patients. Expressions of miR-141-3p and PTEN were detected. WHR and levels of TG, HDL-C, FBG, FINS, HOMA-β, and HOMA-IR showed significant differences in PCOS patients. miR-141-3p was downregulated in PCOS patients. Area under ROC curve of miR-141-3p diagnosing PCOS-obese patients was 0.985 with specificity 95.35% and flexibility 93.33%. Levels of glucose and lipid metabolism indexes were increased while HDL-C level was decreased in miR-141-3p low expression group. Indexes of PCOS-obese patients were improved and miR-141-3p was upregulated after fat reduction intervention. PTEN was upregulated in PCOS patients and negatively correlated with miR-141-3p. In conclusion, miR-141-3p was downregulated in PCOS patients and had higher diagnostic value on PCOS and associated with glucose and lipid metabolism. miR-141-3p might play a role in glucose and lipid metabolism in PCOS-obese patients by targeting PTEN.

Cellular, Extracellular and Extracellular Vesicular miRNA Profiles of Pre-Ovulatory Follicles Indicate Signaling Disturbances in Polycystic Ovaries

Cell-free RNAs have the potential to act as a means of gene expression regulation between cells and are therefore used as diagnostic markers describing the state of tissue environment. The origin and functions of such RNAs in human ovarian follicle, the environment of oocyte maturation, are unclear. The current study investigates the difference in the microRNA profiles of fertile women and polycystic ovary syndrome (PCOS) patients in three compartments from the same preovulatory follicle: mural granulosa cells (MGC), cell-free follicular fluid (FF), and extracellular vesicles (EV) of the FF by small RNA sequencing. In silico analysis was used for the prediction and over-representation of targeted pathways for the detected microRNAs. PCOS follicles were distinguished from normal tissue by the differential expression of 30 microRNAs in MGC and 10 microRNAs in FF (FDR < 0.1) that commonly regulate cytokine signaling pathways. The concentration of EV-s was higher in the FF of PCOS patients (p = 0.04) containing eight differentially expressed microRNAs (p < 0.05). In addition, we present the microRNA profiles of MGC, FF, and EV in the fertile follicle and demonstrate that microRNAs loaded into EVs target mRNAs of distinct signaling pathways in comparison to microRNAs in FF. To conclude, the three follicular compartments play distinct roles in the signaling disturbances associated with PCOS.

Long non-coding RNA TUG1 and its molecular mechanisms in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) causes anovulatory infertility in women of reproductive age, but etiopathogenesis of PCOS remains undetermined. Taurine up-regulated 1 (TUG1), an evolutionarily conserved long non-coding RNA, performs various biological functions; however, the role of TUG1 in PCOS remains unclear. Herein, TUG1 expression was assayed in granulosa cells (GCs) of 100 patients with PCOS and 100 control participants. Receiver operating characteristic (ROC) curve analysis was conducted to determine the diagnostic value of TUG1 in PCOS. TUG1 expression was also silenced in KGN cells to explore the role of TUG1 in cellular proliferation, apoptosis, cell-cycle progression, autophagy, and steroidogenesis. We found that TUG1 levels were dramatically increased in the PCOS group compared with those of the control group; this increased expression was related to a rising antral follicle count (R = 0.209, P < 0.001 versus control). The ROC curve indicated a significant separation between PCOS group and the control group (AUC: 0.702; 95% CI: 0.630-0.773; P < 0.001). TUG1 showed a predominantly nuclear localization in human GCs. TUG1 knockdown reduced cellular proliferation, and promoted MAPKs pathway-dependent apoptosis and P21-dependent autophagy, but may not affect cell-cycle progression. TUG1 knockdown increased aromatase expression and oestradiol biosynthesis. Our results indicate that increased TUG1 expression in PCOS GCs may contribute to excessive follicular activation and growth, and may disrupt the selection of dominant follicle. Our study shows that TUG1 can be used as a diagnostic biomarker for PCOS.

Identification of Crucial lncRNAs, miRNAs, mRNAs, and Potential Therapeutic Compounds for Polycystic Ovary Syndrome by Bioinformatics Analysis

BACKGROUND

This study was aimed at mining crucial long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) for the development of polycystic ovary syndrome (PCOS) based on the coexpression and the competitive endogenous RNA (ceRNA) theories and investigating the underlying therapeutic drugs that may function by reversing the expression of lncRNAs, miRNAs, and mRNAs.

METHODS

RNA (GSE106724, GSE114419, GSE137684, and GSE138518) or miRNA (GSE84376 and GSE138572) expression profile datasets of PCOS patients were downloaded from the Gene Expression Omnibus database. The weighted gene coexpression network analysis (WGCNA) using four RNA datasets was conducted to construct the lncRNA-mRNA coexpression networks, while the common differentially expressed miRNAs in two miRNA datasets and module RNAs were used to establish the ceRNA network. A protein-protein interaction (PPI) network was created to explore the potential interactions between genes. Gene Ontology and KEGG pathway enrichment analyses were performed to explore the functions of genes in networks. Connectivity Map (CMap) and Comparative Toxicogenomics Database (CTD) analyses were performed to identify potential therapeutic agents for PCOS.

RESULTS

Three modules (black, magenta, and yellow) were identified to be PCOS-related after WGCNA analysis, in which KLF3-AS1-PLCG2, MAPKAPK5-AS1-MAP3K14, and WWC2-AS2-TXNIP were important coexpression relationship pairs. WWC2-AS2-hsa-miR-382-PLCG2 was a crucial ceRNA loop in the ceRNA network. The PPI network showed that MAP3K14 and TXNIP could interact with hub genes PLK1 (degree = 21) and TLR1 (degree = 18), respectively. These genes were enriched into mitosis (PLK1), immune response (PLCG2 and TLR1), and cell cycle (TXNIP and PLK1) biological processes. Ten small molecule drugs (especially quercetin) were considered to be therapeutical for PCOS.

CONCLUSION

Our study may provide a novel insight into the mechanisms and therapy for PCOS.

The P53/microRNA network: A potential tumor suppressor with a role in anticancer therapy

MicroRNAs (miRNAs) are endogenous and small non-coding RNAs that have been identified as mediators of tumor suppression as well as stress responses mediated by p53 suppressors. MiRNAs may act as tumor suppressors under certain conditions. MiRNAs regulated by p53 may control the expression of processes such as cell cycle progression, cell survival, and angiogenesis. P53 activity and expression are also controlled by miRNA; consequently alterations in the p53-miRNA network may be essential for tumor initiation and progression. Future studies on the p53-miRNA network presumably would find it helpful in diagnostic and therapeutic approaches or as tools for various cancers.

Inhibition of miRNA-152-3p enhances diabetic wound repair via upregulation of PTEN

Diabetic foot ulcer (DFU) is a major complication of diabetes in the elderly population. The aim of this study was to investigate the potential mechanism of DFU at the molecular level and explore a feasible therapy for it. Using data from the Gene Expression Omnibus (GEO) database, we found that phosphatase and tensin homolog (PTEN) is differentially expressed between diabetic patients and those without diabetes. We also found that PTEN expression is regulated by glucose stimulation. In addition, decreased function of human umbilical vein endothelial cells (HUVECs) was found to be associated with reduction of PTEN. We identified microRNA-152-3p (miR-152-3p) to be a putative upstream negative regulator of PTEN, and in vivo and in vitro results indicated that miR-152-3p antagonist could restore HUVEC function and accelerate wound repair. Thus, miR-152-3p-induced downregulation of PTEN appears responsible for the delayed wound healing in DFU, and miR-152-3p inhibition may effectively accelerate wound repair, thereby providing a potential target for DFU therapy.

Long non-coding RNAs in ovarian granulosa cells

Granulosa cells (GCs) are somatic cells surrounding oocytes within follicles and are essential for folliculogenesis. Pathological changes in GCs are found in several ovarian disorders. Recent reports have indicated that long non-coding RNAs (lncRNAs), which modulate gene expression via multiple mechanisms, are key regulators of the normal development of GCs, follicles, and ovaries. In addition, accumulating evidence has suggested that lncRNAs can be utilized as biomarkers for the diagnosis and prognosis of GC-related diseases, such as polycystic ovary syndrome (PCOS) and premature ovarian insufficiency (POI). Therefore, lncRNAs not only play a role in GCs that are involved in normal folliculogenesis, but they may also be considered as potential candidate biomarkers and therapeutic targets in GCs under pathological conditions. In the future, a detailed investigation of the in vivo delivery or targeting of lncRNAs and large-cohort-validation of the clinical applicability of lncRNAs is required.