Review: Bio-compartmentalization of microRNAs in exosomes during gestational diabetes mellitus

Analysis of the human genome revealed that only 1.2% encoded for proteins, which raised questions regarding the biological significance of the remaining genome. We now know that approximately 80% of the genome serves at least one biochemical function within the cell. A portion of this 80% consists of a family of non-coding regulatory RNAs, one important member being microRNAs (miRNAs). miRNAs can be detected in tissues and biofluids, where miRNAs in the latter can be bound to proteins or encapsulated within lipid vesicles such as exosomes. Gestational diabetes mellitus (GDM) is a complication of pregnancy, which has harmful health impacts on both the fetus as well as the mother. The incidence of GDM worldwide varies, but reached 18% in the HAPO cohort using the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. Not only has GDM been associated with increased risks of further complications during pregnancy, but also poses long-term risks for both the mother and the baby. Thus, understanding the pathophysiology of GDM is important from a public health perspective. Literature has demonstrated that GDM is associated with elevated levels of circulating exosomes in maternal circulation. However, there is a paucity of data defining the expression, role, and diagnostic utility of miRNAs in GDM. This review briefly summarizes recent advances in the function and quantification of intracellular and extracellular miRNAs in GDM.     

DCP1 forms asymmetric trimers to assemble into active mRNA decapping complexes in metazoa

DCP1 stimulates the decapping enzyme DCP2, which removes the mRNA 5′ cap structure committing mRNAs to degradation. In multicellular eukaryotes, DCP1-DCP2 interaction is stabilized by additional proteins, including EDC4. However, most information on DCP2 activation stems from studies in S. cerevisiae, which lacks EDC4. Furthermore, DCP1 orthologs from multicellular eukaryotes have a C-terminal extension, absent in fungi. Here, we show that in metazoa, a conserved DCP1 C-terminal domain drives DCP1 trimerization. Crystal structures of the DCP1-trimerization domain reveal an antiparallel assembly comprised of three kinked α-helices. Trimerization is required for DCP1 to be incorporated into active decapping complexes and for efficient mRNA decapping in vivo. Our results reveal an unexpected connectivity and complexity of the mRNA decapping network in multicellular eukaryotes, which likely enhances opportunities for regulating mRNA degradation.     

Pap Smear miR-92a-5p and miR-155-5p as potential diagnostic biomarkers of squamous intraepithelial cervical cancer

Background: one of the female-specific diseases with a high incidence and mortality is cervical cancer. The main cause of cervical cancer is infection with Human papilloma virus (HPV). Low-grade squamous intraepithelial lesions (LSIL) and High-grade squamous intraepithelial lesions (HSIL) usually is caused by an HPV infection. Considering the role of microRNAs (miRNAs) as diagnostic biomarkers for a variety of cancers, the aim of this study was to determine miR-92a-5p and miR-155-5p expression levels in LSIL and HSIL Pap Smear samples. Methods: After initial bioinformatic studies, A total of 75 samples (25 samples of patients with LSIL, 25 patients with HSIL and 25 healthy individuals) were subjected to RNA extraction and cDNA synthesis. The expressions levels of confirmed miRNAs in samples of patients with LSIL, HSIL and healthy individuals were evaluated by Real time PCR analysis. To demonstration the role of predicted miRNAs as novel biomarkers in diagnosis of LSIL and HSIL, ROC curve analysis was done. Results: Bioinformatics results showed that miR-92a-5p and miR-155-5p target the HPV E6 and E7 genes. The expression levels of these miRNAs were strikingly higher in Pap smear of patients with LSIL than in the healthy individuals (35.36, P = 0.001) (62.23, P = 0.001). Similarity, expression levels of miR-92a-5p and miR-155-5p were amazingly higher in patients with HSIL than in the healthy individuals (33.62, P= 0.001) (69.07, P= 0.001). Although, the levels of miR-92a-5p (0.95, P = 0. 85) and miR-155-5p (1.11, P = 0.84) exhibited no statistical differences between patients with LSIL and HSIL. Also, ROC curve analyses verified that miR-92a-5p and miR-155-5p are specific and sensitive and may serve as new biomarkers for the early detection of cervical cancer. Conclusion: These data suggest miR-92a-5p and miR-155-5p, which are upregulated in LSIL and HSIL, can be consider as predictive biomarkers for the prognosis of cervical cancer patients.     

Plasma Circulating Mirnas Profiling for Identification of Potential Breast Cancer Early Detection Biomarkers

Objective: This study aimed to characterize the miRNA expression profiles from plasma samples of our local breast cancer patients in comparison to healthy control by using miRNA PCR Array. Methods: In this study, plasma miRNA profiles from eight early-stage breast cancer patients and nine age-matched (± 2 years) healthy controls were characterized by miRNA array-based approach, followed by differential gene expression analysis, Independent T-test and construction of Receiver Operating Characteristic (ROC) curve to determine the capability of the assays to discriminate between breast cancer and the healthy control. Results: Based on the 372-miRNAs microarray profiling, a set of 40 differential miRNAs was extracted regarding to the fold change value at 2 and above. We further sub grouped 40 miRNAs of breast cancer patients that were significantly expressed at 2-fold change and higher. In this set, we discovered that 24 miRNAs were significantly upregulated and 16 miRNAs were significantly downregulated in breast cancer patients, as compared to the miRNA expression of healthy subjects. ROC curve analysis revealed that seven miRNAs (miR-125b-5p, miR-142-3p, miR-145-5p, miR-193a-5p, miR-27b-3p, miR-22-5p and miR-423-5p) had area under curve (AUC) value > 0.7 (AUC p-value < 0.05). Overlapping findings from differential gene expression analysis, ROC analysis, and Independent T-Test resulted in three miRNAs (miR-27b-3p, miR-22-5p, miR-145-5p). Cohen’s effect size for these three miRNAs was large with d value are more than 0.95. Conclusion: miR-27b-3p, miR-22-5p, miR-145-5p could be potential biomarkers to distinguish breast cancer patients from healthy controls. A validation study for these three miRNAs in an external set of samples is ongoing.     

膀胱癌miRNAs风险预后模型建立与应用

目的:通过筛选与膀胱癌生存预后相关的非编码小分子核糖核酸(microRNAs,miRNAs),构建风险预后模型评价患者预后。方法:从人类癌症基因图谱（The Cancer Genome Atlas,TCGA）数据库下载膀胱癌miRNAs与mRNAs数据及对应的临床相关信息,筛选差异的miRNAs和mRNAs。对差异的miRNAs进行Kaplan-Meier（K-M）生存分析和单因素Cox回归分析评价筛选得到与预后相关的miRNAs。采用多因素Cox回归进一步分析获得风险模型目标miRNAs,建立最佳风险预后模型,评价模型效能。通过在线数据库和差异mRNAs数据对结合的miRNA靶基因进行筛选,然后进行KEGG和GO富集分析,预测miRNAs靶基因功能。结果:筛选得到膀胱癌差异miRNAs有473个,差异mRNAs有7 106个。运用K-M生存分析及单因素Cox回归筛选得到24个与膀胱癌患者生存预后相关的miRNAs,进一步通过多因素Cox回归得到11个与风险预后模型紧密相关的miRNAs,成功构建miRNAs风险预后模型。模型风险评分=（-0.4×Exphsa-miR-145-5p）+（-0.928×Exphsa-miR-99a-5p）+（-0.295×Exphsa-miR-7705）+（-0.566×Exphsa-miR-590-3p）+（0.201×Exphsa-miR-337-3p）+（0.576×Exphsa-miR-125b-2-3p）+（0.345×Exphsa-miR-652-3p）+（-0.718×Exphsa-miR-143-5p）+（0.286×Exphsa-miR-3065-3p）+（0.282×Exphsa-let-7c-3p）+（0.145×Exphsa-miR-216a-5p）。模型的受试者工作特征曲线(receiver operating characteristic curve,ROC)曲线下面积（the area under the ROC curve,AUC）为0.781,提示风险预后模型具有较好的预测效能。K-M生存分析提示模型评分越高的患者5年生存率越低。GO和KEGG富集分析显示,模型miRNAs能够调控多种泌尿系统活性信号和相关通路,介导膀胱癌疾病进展。结论:成功构建膀胱癌miRNAs风险预后评估模型,为临床膀胱癌患者生存预测提供了一定的价值。     

外泌体miRNAs在乳腺癌肿瘤微环境中的研究进展

乳腺癌是全球女性最常发生的恶性肿瘤,患者死亡的主要原因是复发、转移和耐药性的出现。研究已经证明,外泌体介导癌细胞与肿瘤微环境之间的信息交流,外泌体携带的miRNAs通过差异表达于乳腺癌细胞,在微环境中影响癌基因表达的调控,介导乳腺癌细胞的信号通路,调节癌细胞周期进程以及重塑肿瘤相关成纤维细胞等,从而促进乳腺癌的发生、发展和转移;另外外泌体介导中和、药物外排和免疫系统抑制三种主要机制导致耐药性。未来,各种类型乳腺癌中差异表达的miRNAs有望成为临床诊断和预后的相关生物标志物,及抗肿瘤治疗的新靶点。     

Reprint of: MicroRNA profiling of human intermediate monocytes

Among the three human monocyte subsets, intermediate CD14++CD16+ monocytes have been characterized as particularly proinflammatory cells in experimental studies and as potential biomarkers of cardiovascular risk in clinical cohorts. To further substantiate the distinct role of intermediate monocytes within human monocyte heterogeneity, we assessed subset-specific expression of miRNAs as central epigenetic regulators of gene expression. We hypothesized that intermediate monocytes have a distinct miRNA profile compared to classical and non-classical monocytes.By using small RNA-seq we analyzed 662 miRNAs in the three monocyte subsets. We identified 38 miRNAs that are differentially expressed in intermediate monocytes compared to both classical and non-classical monocytes with a p value of <10⁻¹⁰, of which two miRNAs – miR-6087 (upregulated) and miR-150-5p (downregulated) – differed in their expression more than ten-fold. Pathway analysis of the 38 differentially expressed miRNAs linked intermediate monocytes to distinct biological processes such as gene regulation, cell differentiation, toll-like receptor signaling as well as antigen processing and presentation. Moreover, differentially expressed miRNAs were connected to those genes that we previously identified as markers of intermediate monocytes.In aggregation, we provide first genome-wide miRNA data in the context of monocyte heterogeneity, which substantiate the concept of monocyte trichotomy in human immunity. The identification of miRNAs that are specific for intermediate monocytes may allow to develop strategies, which particularly target this cell population while sparing the other two subsets.     

Comparison of a healthy miRNome with melanoma patient miRNomes: are microRNAs suitable serum biomarkers for cancer?

MiRNAs are increasingly recognized as biomarkers for the diagnosis of cancers where they are profiled from tumor tissue (intracellular miRNAs) or serum/plasma samples (extracellular miRNAs). To improve detection of reliable biomarkers from blood samples, we first compiled a healthy reference miRNome and established a well-controlled analysis pipeline allowing for standardized quantification of circulating miRNAs. Using whole miRNome and custom qPCR arrays, miRNA expression profiles were analyzed in 126 serum, whole blood and tissue samples of healthy volunteers and melanoma patients and in primary melanocyte and keratinocyte cell lines. We found characteristic signatures with excellent prognostic scores only in late stage but not in early stage melanoma patients. Upon comparison of melanoma tissue miRNomes with matching serum samples, several miRNAs were identified to be exclusively tissue-derived (miR-30b-5p, miR-374a-5p and others) while others had higher expression levels in serum (miR-3201 and miR-122-5p). Here we have compiled a healthy and widely applicable miRNome from serum samples and we provide strong evidence that levels of cell-free miRNAs only change significantly at later stages of melanoma progression, which has serious implications for miRNA biomarker studies in cancer.