Serum microRNAs in male subfertility-biomarkers and a potential pathogenetic link to metabolic syndrome

MicroRNA-181b-5p Facilitates Thyroid Cancer Growth via Targeting Programmed Cell Death 4

To explore the potential mechanism of microRNA (miR)-181b-5p promoting the progression of thyroid cancer (TC) by targeting programmed cell death 4 (PDCD4). Analysis of miR-181b-5p and PDCD4 expression in TC was performed. The impact of miR-181b-5p and PDCD4 on proliferation, migration, invasion, and apoptosis of TC cells was examined. The binding relationship between miR-181b-5p and PDCD4 was predicted and verified. miR-181b-5p was up-regulated in TC, while PDCD4 was down-regulated. Down-regulating miR-181b-5p or up-regulating PDCD4 inhibited the proliferation, migration, and invasion of TC cells, and promoted cell apoptosis. PDCD4 was the downstream target of miR-181b-5p, and down-regulation of PDCD4 counteracted the inhibitory effect of down-regulation of miR-181b-5p on the proliferation, migration, and invasion of TC cells and the promoting effect on apoptosis. miR-181b-5p inhibits the proliferation, migration, and invasion of TC cells and promotes cell apoptosis by targeting PDCD4.

Small RNAs, spermatogenesis, and male infertility: a decade of retrospect

Small non-coding RNAs (sncRNAs), being the top regulators of gene expression, have been thoroughly studied in various biological systems, including the testis. Research over the last decade has generated significant evidence in support of the crucial roles of sncRNAs in male reproduction, particularly in the maintenance of primordial germ cells, meiosis, spermiogenesis, sperm fertility, and early post-fertilization development. The most commonly studied small RNAs in spermatogenesis are microRNAs (miRNAs), PIWI-interacting RNA (piRNA), small interfering RNA (siRNA), and transfer RNA-derived small RNAs (ts-RNAs). Small non-coding RNAs are crucial in regulating the dynamic, spatial, and temporal gene expression profiles in developing germ cells. A number of small RNAs, particularly miRNAs and tsRNAs, are loaded on spermatozoa during their epididymal maturation. With regard to their roles in fertility, miRNAs have been studied most often, followed by piRNAs and tsRNAs. Dysregulation of more than 100 miRNAs has been shown to correlate with infertility. piRNA and tsRNA dysregulations in infertility have been studied in only 3-5 studies. Sperm-borne small RNAs hold great potential to act as biomarkers of sperm quality and fertility. In this article, we review the role of small RNAs in spermatogenesis, their association with infertility, and their potential as biomarkers of sperm quality and fertility.

Integrated miRNA Changes in Canine Testis and Epididymis According to Age and Presence of Cryptorchidism

In the present study, we aimed to investigate age-, cryptorchidism-, and testicular tumor-related changes in miRNAs in the testis and epididymis of dogs. Twelve healthy male dogs were divided into two groups: young (<1 year, n = 8) and old (>3 years, n = 4). Five dogs with unilateral cryptorchidism, one with a Sertoli cell tumor, and one with seminoma were referred to a veterinary hospital. After surgery, the testes and epididymis tails were collected. A high-throughput miRNA array analysis was performed to identify miRNAs affected by age, cryptorchidism, and testicular tumors. The expression of only cfa-miR-503 was downregulated in the epididymis of younger dogs, whereas the expression of 64 miRNAs was upregulated. Among them, the top five miRNAs were cfa-miR-26a, cfa-miR-200c, cfa-let-7c, cfa-let-7b, and cfa-let-7a. The expression of cfa-miR-148a and cfa-miR-497 was considerably lower in cryptorchid testis than in healthy dog testis. In the epididymis, the cfa-miR-1841 level was significantly decreased. We observed a significant difference in the expression of 26 cfa-miRNAs between testicular tumors and normal tissues. This study demonstrated that aging and cryptorchidism have a causal relationship with miRNA expression. The identified miRNAs may be candidate genes for male reproductive traits and could be applied in molecular breeding programs.

Using miRNAs as diagnostic biomarkers for male infertility: opportunities and challenges

The non-coding genome has been extensively studied for its role in human development and diseases. MicroRNAs (miRNAs) are small non-coding RNAs, which can regulate the expression of hundreds of genes at the post-transcriptional level. Therefore, any defects in miRNA biogenesis or processing can affect the genes and have been linked to several diseases. Male infertility is a clinical disorder with a significant number of cases being idiopathic. Problems in spermatogenesis and epididymal maturation, testicular development, sperm maturation or migration contribute to male infertility, and many of these idiopathic cases are related to issues with the miRNAs which tightly regulate these processes. This review summarizes the recent research on various such miRNAs and puts together the candidate miRNAs that may be used as biomarkers for diagnosis. The development of strategies for male infertility treatment using anti-miRs or miRNA mimics is also discussed. Although promising, the development of miRNA diagnostics and therapeutics is challenging, and ways to overcome some of these challenges are also reviewed.

The Roles of MicroRNAs in Male Infertility

MicroRNAs applications were vastly studied throughout the years, spanning from potential cancer biomarkers to targeted therapies for various diseases. Out of these utilizations, this paper focuses on their role in male infertility. Approximately 10–15% of worldwide couples are affected by infertility. Out of these, 50% are due to male determinants. The majority of cases still have an undetermined cause. Previous studies have found that the aberrant expression of microRNAs could be linked to certain reproductive dysfunctions in males. Further on, this study looked into the most recent literature published on this subject in order to assess the connection between the up-/down-regulation of various microRNAs and the roles they play in male infertility. MicroRNAs were found to be abundant and stable in the seminal liquid, which led to a facile identification using regular RNA detection methods. It was observed that the concentration of microRNAs in semen was modified in the case of patients suffering from asthenozoospermia and azoospermia. Moreover, idiopathic male infertility was associated with a single nucleotide polymorphism of the microRNA binding site. Future studies should focus their attention on discovering future treatments against male infertility targeting specific microRNAs and also on developing new and improved contraceptive methods.

Expression of miRNA-146b-5p in patients with thyroid cancer in combination with Hashimoto's disease and its clinical significance

The expression level of microRNA (miRNA)-146b in patients with thyroid carcinoma (TC) in combination with Hashimoto's thyroditis (HT) was evaluated to analyze the clinical significance. Eighty-seven patients who underwent thyroid surgery in The Third Affiliated Hospital of Southern Medical University from March 2010 to February 2013 were enrolled. Of the patients, 37 were diagnosed with TC (group A), and 50 were diagnosed with TC in combination with HT (group B). Forty patients were diagnosed with HT (group C). The expression levels of miRNA-146b-5p in cancer tissue and paracancerous tissue of patients in the two groups were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Correlation between the miRNA-146b-5p levels and the clinicopathological characteristics of patients with combined TC and HT were evaluated. According to the expression of miRNA-146b-5p, patients in group B were separated into the high and low expression groups to observe the five-year cancer recurrence rate. There was no significant difference in miRNA-146b-5p expression between the papillary carcinoma group, the follicular carcinoma group and the medullary carcinoma group (P>0.05). The miRNA-146b-5p expression in the lesion tissue of group B was significantly higher than that of groups A and C, while the miRNA-146b-5p expression in the lesion tissue of group A was significantly higher than that of group C (P<0.05), and the lesion tissue of the three groups was higher than that of the corresponding parastatal tissue (P<0.05). The miRNA-146b-5p expression level was associated with tumor size, lymph node metastasis and TNM stage (P<0.05), while not associated with sex, age, lesion multiplicity, smoking history, diabetes history and pathological type in group B (P>0.05). The non-recurrence rate of group B high expression subgroup was lower than that of group B low expression subgroup (P=0.045). High expression of miRNA-146b-5p was found in the cancer tissues of patients with combined TC and HT. The expression level of miRNA-146b-5p was associated with tumor size, lymph node metastasis and TNM stage. It is a potential prognostic indicator for patients with combined TC and HT.

Associations of blood levels of trace elements and heavy metals with metabolic syndrome in Chinese male adults with microRNA as mediators involved

Metabolic syndrome (MetS) is a global health problem with an increasing prevalence. However, effects of trace elements and heavy metals on MetS and the mechanism underlying this effect are poorly understood. A preliminary cross-sectional study was conducted in 2015. Significantly higher blood concentrations of lead (Pb), cadmium (Cd), copper (Cu), and selenium (Se) were observed in the MetS group. With a priori adjustment for age, the concentration of Cu and Se in the blood was associated with a 2.56 - fold [95% confidence interval (CI), 1.11, 5.92] and 3.31 - fold (95% CI, 1.4, 7.82) increased risk of MetS, respectively. Moreover, increased blood Se concentrations were associated with body mass index (BMI) [odds ratio (OR): 2.56; 95% CI, 1.11, 5.93], high blood pressure [for both systolic and diastolic blood pressures (SBP and DBP); OR: 3.82; 95% CI, 1.47, 7.31 for SBP and OR: 2.56; 95% CI, 1.18, 5.59 for DBP], and hypertriglyceridemia (OR: 3.3; 95% CI, 1.51, 7.2). In addition, the expression of miR-21-5p, miR-122-5p, and miR-146a-5p was significantly higher in subjects with MetS than those without MetS. Increased expression of miR-21-5p was significantly associated with increased SBP (β = 5.28; 95% CI, 0.63, 9.94) and DBP (β = 4.17; 95% CI, 0.68, 7.66). Moreover, Cu was positively associated with miR-21-5p (β = 3.02; 95% CI, 0.07, 5.95), whereas Se was positively associated with miR-122-5p (β = 2.7; 95% CI, 0.64, 4.76). The bootstrapping mediation models indicated that miR-21-5p partially mediated the relationships between Cu level and SBP/DBP. This study suggested that Cu and Se were both associated with MetS, and miR-21-5p participated in the development of MetS associated with Cu.

Clinical value of miRNA-122 in the diagnosis and prognosis of various types of cancer

The present study aimed to systematically analyze the value of microRNA-122 (miRNA-122) in the diagnosis and prognosis of hepatocellular carcinoma (HCC) and other types of cancer. First, the reverse transcription-quantitative polymerase chain reaction method was used to detect the expression levels of miRNA-122 in the serum samples of patients with HCC, benign lesions and healthy volunteers. Next, miRNA-seq data of miRNA-122 from The Cancer Genome Atlas database were used to analyze the differential expression and overall survival rate associated with a variety of types of cancer. Meanwhile, the target gene prediction of miRNA-122 was performed using four different software programs. Finally, 353 significant target genes were identified for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis. Finally, it was demonstrated that the expression levels of miRNA-122 in the HCC group were increased compared with the healthy group (P<0.001), but decreased with respect to the benign group (P<0.001). In addition, the combination of the miRNA-122 and a fetoprotein may further improve the diagnostic accuracy between the HCC and healthy groups (area under the curve, 0.980; 95% confidence interval, 0.958–1.000). It was also demonstrated that miRNA-122 exhibited significantly differential expression and the overall survival rate was predicted for various other types of cancer, including colorectal cancer, renal carcinoma, cholangiocarcinoma, prostate cancer and thyroid carcinoma. Functional enrichment analysis demonstrated that the target genes of miRNA-122 may contribute to the composition of the nucleus and cytoplasm, and regulate a variety of biological processes, including cardiac muscle cell differentiation and glucose metabolic processes via protein biosynthesis, estrogen and glucagon associated signaling pathways. These results revealed that miRNA-122 may be an indispensable biomarker for the diagnosis, prognostic evaluation and targeted therapy in pan-cancer.

miRNA and Other Non-Coding RNAs as Promising Diagnostic Markers

Since the discovery of non-coding RNAs (ncRNAs) a new area has emerged in the field of biomarkers. NcRNAs are RNA molecules of different sizes that are transcribed as independent genes or as part of protein coding genes and are not translated, therefore they do not produce proteins. They have been classified according to their size and function and include microRNAs (miRNAs), piwiRNAs (piRNAs), snoRNAs and long non-coding RNAs (lncRNAs). These non-coding RNAs are present in different cell compartments participating in multiple cell functions, but they have also been identified in biological fluids, also known as cell-free or circulating ncRNAs, where they can be detected in exosomes, bound on lipoproteins as well as free circulating molecules. The role of circulating ncRNAs is still under investigation but are believed to be paracrine or endocrine messengers to systematically deliver signals between cells and tissues. Detecting ncRNAs in biological fluids has opened a new field in Clinical Chemistry utilizing them as biomarkers of diseases or prognostic markers for different pathological conditions. Herein, the different types of ncRNAs and their potential in the field of diagnostics are outlined.