Functional variant in microRNA-196a2 contributes to the susceptibility of congenital heart disease in a Chinese population

Associations of Polymorphisms in mir-196a2, mir-146a and mir-149 with Colorectal Cancer Risk: A Meta-Analysis

MicroRNAs (miRNAs) are non-coding RNAs which act as tumor suppressors or oncogenes. And single nucleotide polymorphism (SNP) in miRNA regions is one type of genetic variations in human genome. Various studies have investigated the associations of miRNAs SNP and kinds of cancers. In this article, we searched eligible studies to explore the relationships between mir-196a2 /mir-146a /mir-149 polymorphisms and colorectal cancer (CRC). A literature search of PubMed, Web of Science and ScienceDirect was conducted to identify all relevant studies. Three genetic models with pooled ratio and 95% confidence interval were used to evaluate the associations. We found that mir-196a2 polymorphism was significantly associated with CRC in Asian group (additive model: OR = 1.197, 95%CI 1.084 ~ 1.32, P < 0.001; dominant model: OR = 1.247, 95%CI 1.065 ~ 1.46, P = 0.006; recessive model: OR = 1.298, 95%CI 1.101 ~ 1.531, P = 0.002). And no associations were observed between SNPs of mir-146a, mir-149 and CRC in three genetic models. We also found CRC risk was not associated with mir-146a and mir-149 polymorphisms in population subgroup analysis. The current meta-analysis suggests that mir-196a2 polymorphism is associated with CRC, especially in Asian group. While, no associations have been found between mir-146a /mir-149 polymorphisms and CRC.

Association of miR-146a rs2910164 polymorphism with cardio-cerebrovascular diseases: A systematic review and meta-analysis

The microRNA146a rs2910164 polymorphism has been associated with the development of cardio-cerebrovascular diseases (CCDs); however, the results were inconsistent among different studies. The present report was aimed to investigate the association between rs2910164 G/C polymorphism and the risk of CCDs. Based on the data extracted from 12 eligible studies with a total of 5433 CCD cases and 6278 controls, we performed a meta-analysis to assess the diseases risk of rs2910164 G/C polymorphism under allelic contrast (C vs. G), homozygote comparisons (CC vs. GG), heterozygote comparisons (GC vs. GG), dominant model (CC+GC vs. GG) and recessive models (CC vs. GC+GG) in fixed or random effects models. We also conducted pathway enrichment analyses using the putative and validated miR-146a interacting targets to explore the functional impacts of rs2910164. The current meta-analysis results showed that rs2910164 CC genotype has a decreased risk with overall cardiovascular diseases and the specific coronary artery disease. Stratified analysis based on ethnicity showed that the CC genotype has a decreased risk with CCDs in Chinese population, but has an increased risk with CCDs in Korean and Indian populations. The results from pathway enrichment analysis also revealed the association of rs2910164 G allele with heart function and disease related pathways. Our findings suggested that miR-146a CC genotype might be a protective factor for cardiovascular diseases in Chinese population, but a risk factor in Korean and Indian populations.

Association of the genetic polymorphisms in pre-microRNAs with risk of ischemic stroke in a Chinese population

microRNA (miRNA) plays a role in the pathogenesis of ischemic stroke, and single nucleotide polymorphisms in miRNA genes may contribute to disease susceptibility. However, the effect of miR-146a, miR-196a2, and miR-499 polymorphisms on ischemic stroke susceptibility has been rarely reported. Using the TaqMan assay, we evaluated the association of hsa-miR-146a/rs2910164, hsa-miR-196a2/rs11614913, and hsa-miR-499/rs3746444 polymorphisms with the risk of ischemic stroke in a Chinese population with 531 ischemic stroke patients and 531 control subjects. Rs2910164 C/G genotypes were significantly associated with increased risk of ischemic stroke in different genetic model (homozygote comparison: OR = 2.00, 95% CI, 1.29–3.12, P = 0.002; additive model: OR = 1.35, 95% CI, 1.10–1.65, P = 0.004;dominant model: OR = 1.33, 95% CI, 1.00–1.75, P = 0.049; recessive model: OR = 1.82, 95% CI, 1.20–2.74, P = 0.004). Subjects with allele G of hsa-miR-146a/ rs2910164 also showed increased risk of ischemic stroke (OR = 1.33, 95% CI, 1.09–1.62, P = 0.005). Stratification analysis showed that the association between rs2910164 and the risk of ischemic stroke was more pronounced in subjects over 60 years old, females, non-drinkers, subjects without hypertension or diabetes mellitus. There were significant combined effects between miR-146a/rs2910164 and fasting glucose/low-density lipoprotein cholesterol levels on ischemic stroke susceptibility. However, we failed to find any association between the alleles/genotypes of rs11614913 T/C and ischemic stroke, respectively (P> 0.05). In summary, this study provides evidence that miR-146a/rs2910164 might be associated with a significantly increased risk of ischemic stroke in a Chinese population, and the combined effects between miRNA polymorphism and fasting glucose /blood lipid levels may contribute to stroke pathogenesis.

The association of common polymorphisms in miR-196a2 with waist to hip ratio and miR-1908 with serum lipid and glucose

OBJECTIVE

MicroRNAs (miRNAs) have been implicated in the regulation of cardiometabolic disorders. Given the crucial role of miRNAs in gene expression, genetic variation within miRNA genes is expected to affect miRNA function and substantially contribute to disease risk.

METHODS

2,320 variants in miRNA-encoding sequences were systematically retrieved, and their associations with 17 cardiometabolic traits/diseases were investigated, using genome-wide association studies (GWAS) on glycemic indices, anthropometric measures, lipid traits, blood pressure, coronary artery disease, and type 2 diabetes. Next, target genes of the identified miRNAs that may mediate their effect on the phenotypes were examined. Furthermore, trans- expression quantitative trait loci analysis and luciferase reporter assay to provide functional evidence for our findings were performed.

RESULTS

rs11614913:C/T in miR-196a2 was associated with waist to hip ratio (P-value=1.7 × 10(-5) , β = 0.023). Two target genes, SFMBT1 and HOXC8, which may mediate this association were identfied, and they were shown experimentally as direct targets of miR-196a2. Moreover, rs174561:C/T in miR-1908 was found to be associated with total cholesterol (P-value=6.5 × 10(-16) , β=0.044), LDL-cholesterol (P-value=4.3 × 10(-18) , β=0.049), HDL-cholesterol (P-value=1.7 × 10(-6) , β=0.026), triglyceride (P-value=7.8 × 10(-14) , β=0.038), and fasting glucose (P-value=4.3 × 10(-10) , β=0.02). In addition, a number of miR-1908 target genes were highlighted as potential mediators.

CONCLUSIONS

The results indicated miRNA-dependent regulation of fat distribution by miR-196a2 and of lipid metabolism by miR-1908.

Meta-analysis of Hsa-mir-499 polymorphism (rs3746444) for cancer risk: evidence from 31 case-control studies

BACKGROUND

MicroRNAs (miRNAs) are a family of endogenous, small and non-coding RNAs that regulate gene expression negatively at the post-transcriptional level by suppressing translation or degrading target mRNAs, and are involved in diverse biological and pathological processes. Single nucleotide polymorphisms (SNPs) which are located in the miRNA-coding genes may participate in the process of development and diseases by altering the expression of mature miRNA. Recent studies investigating the association between hsa-mir-499 polymorphism (rs3746444) and cancer risk have yielded conflicting results.

METHODS

In this meta-analysis, we conducted a search of case-control studies on the associations of SNP rs3746444 with susceptibility to cancer in electronic databases. A total of 31 studies involving 12799 cases and 14507 controls were retrieved and the strength of the association was estimated by pooled odds ratios (ORs) and 95% confidence intervals (CIs). Hardy-Weinberg equilibrium (HWE) was assessed by the goodness-of-fit chi-square test in controls. Subgroup analyses were done by racial descent and cancer type. Publication bias of literatures was evaluated by visual inspection of funnel plots and the linear regression asymmetry test by Egger et al. Sensitivity analysis was conducted by excluding one study at a time to examine the influence of individual data set on the pooled ORs.

RESULTS

Overall, significant association between rs3746444 polymorphism and susceptibility to cancer was identified in TC versus TT and TC/CC versus TT (dominant) models. In the stratified analyses, increased risks were found in Asians, but not in Caucasians in all comparison models tested. Moreover, significant association with an increased risk was found in Chinese population. Also, much higher significant association with increased cancer risks were found in Iranian population. In different cancer types, a decreased risk was found in esophageal cancer.

CONCLUSION

Our meta-analysis suggested that hsa-mir-499 rs3746444 T > C polymorphism is associated with the risk of cancer in Asians, mainly in Iranian and Chinese population. However, rs3746444 T > C polymorphism is negatively associated with the risk of esophageal cancer.

Evaluation of a novel functional single-nucleotide polymorphism (rs35010275 G>C) in MIR196A2 promoter region as a risk factor of gastric cancer in a Chinese population

Single-nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) have been suggested to influence the occurrence and progression of cancer through altering the expression and biological function of miRNAs. The aim of this study was to investigate whether the potential functional SNPs in MIR196A2 promoter had effect on the susceptibility to gastric cancer (GC) in a Chinese population.We conducted a 2-stage case-control study (753 cases and 854 controls in testing set; 940 cases and 1061 controls in validation set) to evaluate the association between 2 potential functional SNPs in MIR196A2 promoter (rs12304647 A>C and rs35010275 G>C) and GC risk. The luciferase reporter assay and electrophoretic mobility shift assay were used to examine the functionality of the important polymorphism.We found that the rs35010275 C allele was significantly associated with the decreased risk of GC (adjusted odds ratio = 0.85, 95% confidence interval = 0.77-0.94) in the combined case-control studies. The miR-196a expression levels in GC tissues were significantly higher than that in corresponding adjacent normal tissues (P < 0.001). Besides, each allele of rs35010275 displayed completely opposite effects to influence the transcription activity of MIR196A2 promoter via recruiting different transcription factors or complexes.The functional rs35010275 G>C polymorphism in MIR196A2 promoter was significantly associated with miR-196a expression and influenced the genetic susceptibility to GC.

Polymorphism in microRNA-196a2 contributes to the risk of cardiovascular disease in type 2 diabetes patients

AIMS

To investigate the effect of the microRNA-196a2 gene polymorphism (rs11614913) on risk of cardiovascular disease in type 2 diabetes patients.

METHODS

We examined 920 patients with diabetes and 834 healthy controls. All subjects were genotyped for the miRNA-196a2 SNP by polymerase chain reaction (PCR) and restriction analysis.

RESULTS

The genotype distribution among controls and patients was in Hardy-Weinberg equilibrium (p=0.227 and 0.308, respectively). The frequency of the T allele was lower in patients than in controls (p=0.044). The odds ratio 0.66 (95% CI 0.54-0.79) suggests an association of the T allele with decreased risk of T2DM. For the main purpose of the study, T2DM patients were stratified into patients with CVD and those without it. The T allele and TT genotype were significantly more frequent in patients with CVD compared to those without CVD (p=0.013, p<0.001, respectively). The odds ratio for the T allele in the CVD+subgroup vs. CVD- was 1.76 (1.35-2.30), p<0.0001, mostly due to the overrepresentation of TT homozygotes. The highest risk of development of CVD was observed in the additive model for TT homozygotes (OR 3.33, 95% CI 2.05-5.42, p<0.0001).

CONCLUSION

Our findings suggest that miRNA-196a2 T/C polymorphism (rs11614913) is associated with an increased risk of CVD in type 2 diabetes patients. This provides further insights on pathogenesis of cardiovascular disease in type 2 diabetes patients.

Characterization of circulating microRNA expression in patients with a ventricular septal defect

OBJECTIVES

Ventricular septal defect (VSD), one of the most common types of congenital heart disease (CHD), results from a combination of environmental and genetic factors. Recent studies demonstrated that microRNAs (miRNAs) are involved in development of CHD. This study was to characterize the expression of miRNAs that might be involved in the development or reflect the consequences of VSD.

METHODS

MiRNA microarray analysis and reverse transcription-polymerase chain reaction (RT-PCR) were employed to determine the miRNA expression profile from 3 patients with VSD and 3 VSD-free controls. 3 target gene databases were employed to predict the target genes of differentially expressed miRNAs. miRNAs that were generally consensus across the three databases were selected and then independently validated using real time PCR in plasma samples from 20 VSD patients and 15 VSD-free controls. Target genes of validated 8 miRNAs were predicted using bioinformatic methods.

RESULTS

36 differentially expressed miRNAs were found in the patients with VSD and the VSD-free controls. Compared with VSD-free controls, expression of 15 miRNAs were up-regulated and 21 miRNAs were downregulated in the VSD group. 15 miRNAs were selected based on database analysis results and expression levels of 8 miRNAs were validated. The results of the real time PCR were consistent with those of the microarray analysis. Gene ontology analysis indicated that the top target genes were mainly related to cardiac right ventricle morphogenesis. NOTCH1, HAND1, ZFPM2, and GATA3 were predicted as targets of hsa-let-7e-5p, hsa-miR-222-3p and hsa-miR-433.

CONCLUSION

We report for the first time the circulating miRNA profile for patients with VSD and showed that 7 miRNAs were downregulated and 1 upregulated when matched to VSD-free controls. Analysis revealed target genes involved in cardiac development were probably regulated by these miRNAs.

No association of pri-miR-143 rs41291957 polymorphism with the risk of congenital heart disease in a Chinese population

MiR-143 plays an important role in the heart development of zebra fish. The rs41291957 variant located in the pri-miR-143 sequence is associated with colorectal carcinogenesis. Therefore, the authors hypothesized that rs41291957 in pri-miR-143 might be involved in the risk of sporadic congenital heart disease (CHD). The authors conducted a case-control study of CHD in a Chinese population to test their hypothesis by genotyping pri-miR-143 rs41291957 in 1,109 CHD cases and 915 non-CHD control subjects. Logistic regression analyses showed no significant association of genotype or allele frequencies of pri-miR-143 rs41291957 A/G polymorphism with the CHD cases in overall or various subtypes compared with the control group. To the authors' knowledge, this is the first study to investigate the relationship between miR-143 and CHD cases. The results demonstrated that rs41291957 in pri-miR-143 has no major role in genetic susceptibility to sporadic CHD, at least in the current study population.

miR-10a and miR-10b target the 3'-untranslated region of TBX5 to repress its expression

As a well-known transcription factor, TBX5 is involved in embryonic cardiac development. Although TBX5 functions in a dose-dependent manner, the posttranscriptional regulation of human TBX5 is poorly understood. Thus, this study aimed to identify microRNAs that modulate TBX5 expression. Luciferase assays were used to screen miRNAs predicted to modulate TBX5 expression. Using quantitative reverse transcriptase-polymerase chain reaction and Western blot analysis, the authors found that miR-10a and miR-10b significantly repressed TBX5 expression and decreased TBX5 protein levels by targeting the TBX5 3'-untranslated region. In addition, miR-10a and miR-10b expression levels were respectively 2.77 and 3.51 times higher in the heart tissues of congenital heart disease patients than in healthy control subjects, suggesting that they are potential diagnostic biomarkers. In conclusion, the study results indicate that miR-10a and miR-10b inhibit TBX5 expression at the level of translation. Higher levels of miR-10a and miR-10b expression are associated with a higher risk of congenital heart defects.

MicroRNA-421 Dysregulation is Associated with Tetralogy of Fallot

The importance of microRNAs for maintaining stability in the developing vertebrate heart has recently become apparent. In addition, there is a growing appreciation for the significance of microRNAs in developmental pathology, including the formation of congenital heart defects. We examined the expression of microRNAs in right ventricular (RV) myocardium from infants with idiopathic tetralogy of Fallot (TOF, without a 22q11.2 deletion), and found 61 microRNAs to be significantly changed in expression in myocardium from children with TOF compared to normally developing comparison subjects (O’Brien et al. 2012). Predicted targets of microRNAs with altered expression were enriched for gene networks that regulate cardiac development. We previously derived a list of 229 genes known to be critical to heart development, and found 44 had significantly changed expression in TOF myocardium relative to normally developing myocardium. These 44 genes had significant negative correlations with 33 microRNAs, each of which also had significantly changed expression. Here, we focus on miR-421, as it is significantly upregulated in RV tissue from infants with TOF; is predicted to interact with multiple members of cardiovascular regulatory pathways; and has been shown to regulate cell proliferation. We knocked down, and over expressed miR-421 in primary cells derived from the RV of infants with TOF, and infants with normally developing hearts, respectively. We found a significant inverse correlation between the expression of miR-421 and SOX4, a key regulator of the Notch pathway, which has been shown to be important for the cardiac outflow track. These findings suggest that the dysregulation of miR-421 warrants further investigation as a potential contributor to tetralogy of Fallot.

Novel insights into miRNA in lung and heart inflammatory diseases

MicroRNAs (miRNAs) are noncoding regulatory sequences that govern posttranscriptional inhibition of genes through binding mainly at regulatory regions. The regulatory mechanism of miRNAs are influenced by complex crosstalk among single nucleotide polymorphisms (SNPs) within miRNA seed region and epigenetic modifications. Circulating miRNAs exhibit potential characteristics as stable biomarker. Functionally, miRNAs are involved in basic regulatory mechanisms of cells including inflammation. Thus, miRNA dysregulation, resulting in aberrant expression of a gene, is suggested to play an important role in disease susceptibility. This review focuses on the role of miRNA as diagnostic marker in pathogenesis of lung inflammatory diseases and in cardiac remodelling events during inflammation. From recent reports, In this context, the information about the models in which miRNAs expression were investigated including types of biological samples, as well as on the methods for miRNA validation and prediction/definition of their gene targets are emphasized in the review. Besides disease pathogenesis, promising role of miRNAs in early disease diagnosis and prognostication is also discussed. However, some miRNAs are also indicated with protective role. Thus, identifications and usage of such potential miRNAs as well as disruption of disease susceptible miRNAs using antagonists, antagomirs, are imperative and may provide a novel therapeutic approach towards combating the disease progression.

Recurrent miscarriage and micro-RNA among north Indian women

Micro-RNAs (miRNAs) regulate diverse cellular processes such as cell differentiation, proliferation and apoptosis. Mutation in miRNAs results in various pathological conditions such as inflammation, viral infections, neurodegeneration, autoimmunity, and so on. We have evaluated the association of miR-146aC > G (rs2910164), miR-149T > C (rs2292832), miR-196a2T > C (rs11614913), and miR-499A > G (rs3746444) among patients with recurrent miscarriage (RM) and controls from North India. All the 200 patients with RM reported to experience at least 3 unexplained miscarriages before 20th week of gestation. Three hundred fertile women with no history of RMs were taken as controls. Both patients and controls were genotyped by the polymerase chain reaction amplification followed by restriction fragment length polymorphism. Variant alleles and genotypes of miR-499 A > G (Single Nucleotide Polymorphism Database [dbSNP] ID rs3746444) were found to be significant risks associated with patients having RM (odds ratio [OR] = 1.98; 95% confidence interval [CI] = 1.40-2.81; P value = .0001) and controls (OR = 3.64; 95% CI = 1.33-9.94; P value = .0109). A significant susceptible effect was found at allelic level in miR-196aT > C (dbSNP ID rs11614913) and miR-499 A > G (dbSNP ID rs3746444).

Environmental exposures in utero and microRNA

PURPOSE OF REVIEW

Understanding the effects of in-utero exposures to environmental agents is of great importance as the resulting deregulation of biological processes can affect both fetal development and health outcomes that manifest later in life. Due to their established role in developmental processes and inherent stability ex vivo, microRNAs (miRNAs) have emerged as attractive candidates to explore the impact of such exposures during this critical window of susceptibility. In this review, we summarize the findings of studies assessing miRNAs as markers of in-utero environmental exposures and as candidates for the molecular basis through which these exposures exert their influence on children's health.

RECENT FINDINGS

To date, miRNA expression profiles due to various in-utero environmental exposures, including xenochemicals, endogenous factors, and nutritional status, have been reported.

SUMMARY

While the validity of the identified exposure-specific miRNA profiles remains to be established, the findings thus far do raise interesting questions worth addressing in future studies. Gaps that remain to be addressed include linking specific in-utero exposures to subsequent health outcomes based on established miRNA expression profiles and experimentally validating putative downstream targets of the deregulated miRNAs.

A common variant in pre-miR-146 is associated with coronary artery disease risk and its mature miRNA expression

miRNAs are small non-coding RNAs that play an important role in numerous physiological processes. Common single nucleotide polymorphisms (SNPs) in pre-miRNAs may change their property through altering miRNAs expression and/or maturation, resulting in diverse functional consequences. To date, the role of genetic variants in pre-miRNAs on coronary artery disease (CAD) risk remains poorly understood. Here we aimed to evaluate the influence of three common SNPs in pre-miRNAs (miR-146a rs2910164 G>C, miR-196a2 rs11614913 C>T, miR-499 rs3746444 T>C) on individual susceptibility to CAD in a Chinese population of 295 CAD patients and 283 controls. Genotyping was performed using polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method. In a logistic regression analysis, we detected an association of rs2910164 in pre-miR-146a with the CAD risk; compared with the GG homozygotes, the GC heterozygotes [odds ratio (OR)=1.89, 95% confidence interval (CI)=1.06-3.36, P=0.029] and the CC homozygotes (OR=1.83, 95% CI=1.01-3.32, P=0.046) genotype were statistically significantly associated with the increased risk for CADs. As we used further genotype association models, we found a similar trend of the association in recessive model (OR=1.86, 95% CI=1.09-3.19, P=0.023). We also found that the genotypes of miR-146a rs2910164 were associated with its mature miRNA expression by analyzing 23 PBMC samples from CAD patients. Individuals carrying rs11614913 GC or CC genotypes showed 3.2-fold higher expression compared to GG genotype carriers (P<0.05). We observed no association of the other two SNPs in miR-196a2 (rs11614913) and miR-499 (rs3746444) with the CAD incidence. Our data provide the first evidence that the miR-146a rs2910164 polymorphism is associated with increased risk of CAD in Chinese Han population, which may be through influencing the expression levels of the miRNA.

Hsa-miR-196a2 polymorphism increases the risk of acute lymphoblastic leukemia in Chinese children

Acute lymphoblastic leukemia (ALL) is a major cause of mortality and morbidity in childhood, and the causes of ALL are not completely understood. microRNAs (miRNAs) regulate various biological processes including organ development, cell growth regulation, cell differentiation, apoptosis, and tumorigenesis. We performed a case-control study with 570 childhood ALL cases and 673 cancer-free controls to investigate the association between hsa-miR-196a2 rs11614913 T>C polymorphism and ALL risk. The bioinformatics was used to estimate the potential target of hsa-miR-196a2. In the present study, the hsa-miR-196a2 variant TC heterozygote, and CC/TC genotypes were found to be associated with a significantly increased childhood ALL risk, compared with the TT wild-type homozygote (adjusted OR=1.50, 95% CI=1.15-1.95 for TC and OR=1.40, 95% CI=1.09-1.79 for CC/TC). Further, the difference was pronounced in younger (≤6) subjects or parental non-drinker. The significance of the increased risk is more obvious than the higher treatment branch. Additionally, we found that the rs11614913 TC genotype can increase B-phenotype ALL risk (OR=1.37, 95% CI=1.07-1.76). Finally, combination of three bioinformatics approaches revealed that HOXC8 may be the target gene of hsa-miR-196a2. Taken together, our finding suggested that hsa-miR-196a2 rs11614913 T>C may increase the risk of childhood ALL. Large studies with the function of hsa-miR-196a2 are needed in the further study.

A functional polymorphism in MIR196A2 is associated with risk and progression of nasopharyngeal carcinoma in the Chinese population

BACKGROUND

Genetic variations in microRNAs may alter their processing, expression, and binding to target mRNAs, consequently affecting many cancer-related biological processes. Recently, a polymorphism rs11614913 in MIR196A2 was shown to affect the processing of the precursor microRNA into its mature forms and the repertoire of target mRNAs with which it interacts. We examined whether this polymorphism was relevant to the risk of occurrence or progression of nasopharyngeal carcinoma (NPC) in the Chinese population.

METHODS

We genotyped the MIR196A2 rs11614913 in a case-control study of 1084 patients with NPC and 1036 cancer-free controls using the TaqMan assay. The genetic associations with the risk of occurrence and progression of NPC were analyzed by logistic regression.

RESULTS

We observed a significantly increased occurrence of NPC associated with the rs11614913 T allele (odds ratio [OR]=1.15, 95% confidence interval [CI]=1.02-1.32, p=0.026) compared with the C allele. The T allele was also significantly associated with the advanced local tumor invasion (T₃+T₄ vs. T₁+T₂; OR=1.27, 95% CI=1.04-1.54, p=0.015) and advanced lymph node metastasis (N₂+N₃ vs. N₀+N₁; OR=1.23, 95% CI=1.02-1.49, p=0.031) of NPC compared with the C allele. Furthermore, stratified analysis indicated that the increased susceptibility to advanced lymph node metastasis of NPC related to the T allele was more pronounced in patients with a positive family history (N₂+N₃ vs. N₀+N₁; p=0.016, test for homogeneity).

CONCLUSIONS

Our study suggests that the functional polymorphism rs11614913 in the MIR196A2 gene may contribute to the risk of occurrence and progression of NPC in the Chinese population.

MicroRNAs: a new piece in the paediatric cardiovascular disease puzzle

Cardiovascular diseases in children comprise a large public health problem. The major goals of paediatric cardiologists and paediatric cardiovascular researchers are to identify the cause(s) of these diseases to improve treatment and preventive protocols. Recent studies show the involvement of microRNAs (miRs) in different aspects of heart development, function, and disease. Therefore, miR-based research in paediatric cardiovascular disorders is crucial for a better understanding of the underlying pathogenesis of the disease, and unravelling novel, efficient, preventive, and therapeutic means. The ultimate goal of such research is to secure normal cardiac development and hence decrease disabilities, improve clinical outcomes, and decrease the morbidity and mortality among children. This review focuses on the role of miRs in different paediatric cardiovascular conditions in an effort to encourage miR-based research in paediatric cardiovascular disorders.

miRNAs and long noncoding RNAs as biomarkers in human diseases

Noncoding RNAs (ncRNAs) are transcripts that have no apparent protein-coding capacity; however, many ncRNAs have been found to play a major biological role in human physiology. Their deregulation is implicated in many human diseases, but their exact roles are only beginning to be elucidated. Nevertheless, ncRNAs are extensively studied as a novel source of biomarkers, and the fact that they can be detected in body fluids makes them extremely suitable for this purpose. The authors mainly focus on ncRNAs as biomarkers in cancer, but also touch on other human diseases such as cardiovascular diseases, autoimmune diseases, neurological disorders and infectious diseases. The authors discuss the established methods and provide a selection of emerging new techniques that can be used to detect and quantify ncRNAs. Finally, the authors discuss ncRNAs as a new strategy for therapeutic interventions.

A functional variant of pre-miRNA-196a2 confers risk for Behcet's disease but not for Vogt-Koyanagi-Harada syndrome or AAU in ankylosing spondylitis

This study aimed to investigate the predisposition of common pre-miRNA SNPs with Behcet's disease (BD), Vogt-Koyanagi-Harada (VKH) syndrome and acute anterior uveitis (AAU) associated with ankylosing spondylitis (AS). A two-stage association study was carried out in 859 BD, 400 VKH syndrome, 209 AAU(+)AS(+) patients and 1,685 controls all belonging to a Chinese Han population. Genotyping, the expression of miR-196a and Bach1 (the target gene of miR-196a), cell proliferation, cytokine production were examined by PCR-RFLP, real-time PCR, CCK8 and ELISA. In the first stage study, the results showed significantly increased frequencies of the miR-196a2/rs11614913 TT genotype and T allele in BD patients (adjusted P(c) = 0.024, OR = 1.63; adjusted P(c) = 5.4 × 10(-3), OR = 1.45, respectively). However, no significant association of the tested SNPs with VKH and AAU(+)AS(+) patients was observed. The second stage and combined studies confirmed the association of rs11614913 with BD (TT genotype: adjusted P(c) = 6×10(-5), OR = 1.53; T allele: adjusted P(c) = 8×10(-6), OR = 1.35; CC genotype: adjusted P(c) = 0.024, OR = 0.68). A stratified analysis showed an association of the rs11614913 TT genotype and T allele with the arthritis subgroup of BD (P(c) = 5.3 × 10(-3), OR = 1.89; P(c) = 0.015, OR = 1.56, respectively). Functional experiments showed a decreased miR-196a expression, an increased Bach1 expression and an increased production of IL-1β and MCP-1 in TT cases compared to CC cases (P = 0.023, P = 0.0073, P = 0.012, P = 0.002, respectively). This study shows that a functional variant of miR-196a2 confers risk for BD but not for VKH syndrome or AAU(+)AS(+) by modulating the miR-196a gene expression and by regulating pro-inflammatory IL-1β and MCP-1 production.

Emerging roles for miRNAs in the development, diagnosis, and treatment of diabetic nephropathy

Although the causes of diabetic nephropathy are not yet fully known, emerging evidence suggests a role for epigenetic factors in the development of the disease. In particular, microRNAs (miRNAs) are becoming recognized as important mediators of biological processes relevant to diabetic nephropathy. Until recently, investigations of miRNAs in the development of diabetic nephropathy have remained relatively limited; however, the number of reports identifying potential new candidates and mechanisms of impact is presently expanding at a rapid pace. This review seeks to summarize these recent findings, focusing on new candidates and/or novel mechanisms, including the intersection between genetic variation and miRNA function in modulating disease expression, emerging in the field. We also review the latest advances in the diagnostic and therapeutic potential of miRNAs in the treatment of diabetic nephropathy.

microRNAs in cardiac development and regeneration

Heart development involves the precise orchestration of gene expression during cardiac differentiation and morphogenesis by evolutionarily conserved regulatory networks. miRNAs (microRNAs) play important roles in the post-transcriptional regulation of gene expression, and recent studies have established critical functions for these tiny RNAs in almost every facet of cardiac development and disease. The realization that miRNAs are amenable to therapeutic manipulation has also generated considerable interest in the potential of miRNA-based drugs for the treatment of a number of human diseases, including cardiovascular disease. In the present review, I discuss well-established and emerging roles of miRNAs in cardiac development, their relevance to congenital heart disease and unresolved questions in the field for future investigation, as well as emerging therapeutic possibilities for cardiac regeneration.

A genome-wide association study identifies two risk loci for congenital heart malformations in Han Chinese populations

Congenital heart malformation (CHM) is the most common form of congenital human birth anomaly and is the leading cause of infant mortality. Although some causative genes have been identified, little progress has been made in identifying genes in which low-penetrance susceptibility variants occur in the majority of sporadic CHM cases. To identify common genetic variants associated with sporadic non-syndromic CHM in Han Chinese populations, we performed a multistage genome-wide association study (GWAS) in a total of 4,225 CHM cases and 5,112 non-CHM controls. The GWAS stage included 945 cases and 1,246 controls and was followed by 2-stage validation with 2,160 cases and 3,866 controls. The combined analyses identified significant associations (P < 5.0 × 10⁻⁸) at 1p12 (rs2474937 near TBX15; odds ratio (OR) = 1.40; P = 8.44 × 10⁻¹⁰) and 4q31.1 (rs1531070 in MAML3; OR = 1.40; P = 4.99 × 10⁻¹²). These results extend current knowledge of genetic contributions to CHM in Han Chinese populations.

Genetics of congenital heart disease: the glass half empty

Congenital heart disease (CHD) is the most common congenital anomaly in newborn babies. Cardiac malformations have been produced in multiple experimental animal models, by perturbing selected molecules that function in the developmental pathways involved in myocyte specification, differentiation, or cardiac morphogenesis. In contrast, the precise genetic, epigenetic, or environmental basis for these perturbations in humans remains poorly understood. Over the past few decades, researchers have tried to bridge this knowledge gap through conventional genome-wide analyses of rare Mendelian CHD families, and by sequencing candidate genes in CHD cohorts. Although yielding few, usually highly penetrant, disease gene mutations, these discoveries provided 3 notable insights. First, human CHD mutations impact a heterogeneous set of molecules that orchestrate cardiac development. Second, CHD mutations often alter gene/protein dosage. Third, identical pathogenic CHD mutations cause a variety of distinct malformations, implying that higher order interactions account for particular CHD phenotypes. The advent of contemporary genomic technologies including single nucleotide polymorphism arrays, next-generation sequencing, and copy number variant platforms are accelerating the discovery of genetic causes of CHD. Importantly, these approaches enable study of sporadic cases, the most common presentation of CHD. Emerging results from ongoing genomic efforts have validated earlier observations learned from the monogenic CHD families. In this review, we explore how continued use of these technologies and integration of systems biology is expected to expand our understanding of the genetic architecture of CHD.

Four common polymorphisms in microRNAs and the risk of adult glioma in a Chinese case-control study

Emerging evidence has shown that microRNAs (miRNAs) participate in human carcinogenesis as tumor suppressors or oncogenes. It has been suggested that four common single nucleotide polymorphisms (SNPs; miR-146aG > C, 149C > T, 196a2C > T, and 499A > G) are associated with susceptibility to numerous malignancies. However, published results are inconsistent and inclusive. To further investigate the role of these loci, we examined the association of the miRNA polymorphisms with the risk of gliomas in a Han population in northeastern China. Both miR-146aG > C and 196a2C > T showed allelic differences between glioma patients and healthy controls in the studied population, with an OR of 1.30 (P = 0.0006) and an odds ratio (OR) of 1.25 (P = 0.003), respectively. Logistic regression analysis also revealed that the 146aG > C and 196a2C > T wild-type homozygous carriers had an increased glioma risk compared to the variant carriers. Besides, in pairwise comparisons two SNP combinations were associated with the risk of glioma. Among others, carriers of both homozygous risk genotypes, i.e., 146aGG and 196a2CC were associated with a nearly 4-fold increased risk of glioma (OR = 3.77, P = 1.3 × 10(-4)). Overall, glioma risk increased with increasing numbers of risk variant alleles. These results suggest that the miR-146aG > C and 196a2C > T might influence the risk of developing glioma in a northeastern Han Chinese population.

Evaluation of single nucleotide polymorphisms in microRNAs (hsa-miR-196a2 rs11614913 C/T) from Brazilian women with breast cancer

Background

Emerging evidence has shown that miRNAs are involved in human carcinogenesis as tumor suppressors or oncogenes. Single nucleotide polymorphisms (SNPs) located in pre-miRNAs may affect the processing and therefore, influence the expression of mature miRNAs. Previous studies generated conflicting results when reporting association between the hsa-miR-196a2 rs11614913 common polymorphism and breast cancer.

Methods

This study evaluated the hsa-miR-196a2 rs11614913 SNP in 388 breast cancer cases and 388 controls in Brazilian women. Polymorphism was determined by real-time PCR; control and experimental groups were compared through statistical analysis using the X² or Fisher’s exact tests.

Results

The analysis of the SNPs frequencies showed a significant difference between the groups (BC and CT) in regards to genotype distribution (χ²: p = 0.024); the homozygous variant (CC) was more frequent in the CT than in the BC group (p = 0.009). The presence of the hsa-miR-196a2 rs11614913 C/T polymorphism was not associated with histological grades (p = 0.522), axillary lymph node positive status (p = 0.805), or clinical stage (p = 0.670) among the breast cancer patients.

Conclusions

The results of this study indicated that the CC polymorphic genotype is associated with a decreased risk of BC and the presence of the T allele was significantly associated with an increased risk of BC.

A variant in microRNA-196a2 is not associated with susceptibility to and progression of colorectal cancer in Chinese

BACKGROUND

MicroRNAs (miRNAs) are small non-coding RNAs with regulatory functions as tumour suppressors and oncogenes. Although single nucleotide polymorphism (SNP) in miRNA regions have been reported to be rare and unlikely to be functionally important, recent evidence suggested that rs11614913 SNP in miR-196a2 was associated with the susceptibility of lung cancer, breast cancer, congenital heart disease and shortened survival time of non-small-cell lung cancer.

AIMS

The aim of this study was to investigate the association between this genetic variant and the risk and/or progression of colorectal cancer (CRC).

METHODS

A total of 126 CRC patients and 407 healthy controls was periodically enrolled. DNA was extracted from blood specimens, and miR-196a2 polymorphism was genotyped by polymerase chain reaction-ligation detection reaction (PCR-LDR).

RESULTS

Although the frequency of CC homozygotes or miR-196a2C allele-containing genotypes (CT and CC) was lower in CRC patients than in the healthy controls, no significant association between miR-196a2 polymorphism and the risk of CRC was found. The frequency of the 'C' allele in CRC patients was also not significantly lower than in healthy controls. In a subsequent analysis of the association between this polymorphism and the progression of CRC, there was still no significant difference in both genotype and allelic frequency.

CONCLUSIONS

Our results suggest that miR-196a2 polymorphism is not associated with both an increased risk and progression of CRC in Chinese.

Genetic variation in a hsa-let-7 binding site in RAD52 is associated with breast cancer susceptibility

Genetic variants may influence miRNA-mRNA interaction through modulate binding affinity, creating or destroying miRNA-binding sites. Twenty-four single nucleotide polymorphisms (SNPs) that were predicted to affect the binding affinity of breast cancer-related miRNAs to 3'-untranslated regions (UTR) of known genes were genotyped in 878 breast cancer cases and 900 controls in Chinese women. Three promising SNPs (rs10494836, rs10857748 and rs7963551) were further validated in additional 914 breast cancer cases and 967 controls. The variant allele (C) of rs7963551 at 3'-UTR of RAD52 showed a consistently reduced breast cancer risk in two stages with a combined odds ratio (OR) of 0.84 [95% confidence interval (CI) = 0.75-0.95], which was more prominent among women with early age at first live birth (OR = 0.71, 95% CI = 0.58-0.87). A significant interaction was observed between rs7963551 and age at first live birth on breast cancer risk (P for interaction = 0.04). Luciferase activity assay showed a higher expression level for rs7963551 C allele as compared with A allele (P = 5.19 × 10(-3) for MCF-7 cell lines), which might be due to a reduced inhibition from a weakened binding capacity of miRNA to 3'-UTR of RAD52 harboring C allele. These findings indicate that rs7963551 located at hsa-let-7 binding site may alter expression of RAD52 through modulating miRNA-mRNA interaction and contribute to the development of breast cancer in Chinese women.

The association between hsa-miR-499 T>C polymorphism and cancer risk: a meta-analysis

MicroRNAs regulate gene expression at the post-transcriptional level and were involved in diverse biological and pathological processes. Single nucleotide polymorphism (SNP) which is located in the pre-miRNA may affect the processing and then influence the expression of mature miRNA. Previous studies yielded conflicting results as to the association of a common polymorphism in pre-miRNAs (i.e. hsa-miR-499 rs3746444) with various diseases. Therefore, here we performed a meta-analysis to address the association between this polymorphism and cancer risks. A total of twenty studies involving 10,584 cases and 12,414 controls were retrieved based on PubMed. No significant association was found either in cancers and other diseases in all genetic models. And then in the stratified analysis by ethnicity, significantly increased risks were found in Asians (OR=1.11; 95% CI=1.00-1.23 for C vs. T; OR=1.16; 95% CI=1.00-1.36 for TC vs. TT; OR=1.15; 95%CI=1.01-1.31 for TC/CC vs. TT), but not in Caucasians in all comparison models tested. Our meta-analysis suggested that polymorphism of hsa-miR-499 rs3746444 T>C was not associated with the increased susceptibility to cancers and other diseases.

Association of miR-146aC>G, miR-196a2T>C, and miR-499A>G polymorphisms with risk of premature ovarian failure in Korean women

We investigated whether microRNA (miRNA) polymorphisms (miR-146aC>G, miR-196a2T>C, and miR-499A>G) confer risk of premature ovarian failure (POF) in Korean women. DNA samples from 136 patients with POF and 234 controls were genotyped for the 3 miRNA single-nucleotide polymorphisms by polymerase chain reaction-restriction fragment length polymorphism. The miR-146aCG/miR-196a2TC combined genotype was less frequent in patients than in controls (P < .05), conferring less susceptibility. Using haplotype-based multifactor dimensionality reduction analysis, the C-C-A and G-T-A inferred haplotypes (miR-146a/miR-196a2/miR-499) were less frequent in patients, suggesting protective effects (P < .05 for each), whereas the C-T-A and G-C-A haplotypes were more frequent in patients (P < .05 for each). The C-T and G-C haplotypes (miR-146a/miR-196a2) were more frequent in patients, whereas the C-C and G-T haplotypes were less frequent in patients (P < .05 for each). However, none of the 3 miRNA polymorphisms alone was associated with POF risk. Our findings suggest that putative gene-gene interaction between miR-146 and miR-196a2 may be involved in POF development.

Noncoding RNA expression in myocardium from infants with tetralogy of Fallot

BACKGROUND

The importance of noncoding RNAs (ncRNA), especially microRNAs (miRNAs), for maintaining stability in the developing vertebrate heart has recently become apparent; however, there is little known about the expression pattern of ncRNA in the human heart with developmental anomalies.

METHODS AND RESULTS

We examined the expression of miRNAs and small nucleolar RNAs (snoRNAs) in right ventricular myocardium from 16 infants with nonsyndromic tetralogy of Fallot (TOF) without a 22q11.2 deletion, 3 fetal heart samples, and 8 normally developing infants. We found 61 miRNAs and 135 snoRNAs to be significantly changed in expression in myocardium from children with TOF compared with normally developing comparison subjects. The pattern of ncRNA expression in TOF myocardium had a surprising resemblance to expression patterns in fetal myocardium, especially for the snoRNAs. Potential targets of miRNAs with altered expression were enriched for gene networks of importance to cardiac development. We derived a list of 229 genes known to be critical to heart development and found 44 had significantly changed expression in TOF myocardium relative to normally developing myocardium. These 44 genes had significant negative correlation with 33 miRNAs, each of which also had significantly changed expression. The primary function of snoRNAs is targeting specific nucleotides of ribosomal RNAs and spliceosomal RNAs for biochemical modification. The targeted nucleotides of the differentially expressed snoRNAs were concentrated in the 28S and 18S ribosomal RNAs and 2 spliceosomal RNAs, U2 and U6. In addition, in myocardium from children with TOF, we observed splicing variants in 51% of genes that are critical for cardiac development. Taken together, these observations suggest a link between levels of snoRNA that target spliceosomal RNAs, spliceosomal function, and heart development.

CONCLUSIONS

This is the first report characterizing ncRNA expression in a congenital heart defect. The striking shift in expression of ncRNAs reflects a fundamental change in cell biology, likely impacting expression, transcript splicing, and translation of developmentally important genes and possibly contributing to the cardiac defect.

ISL1 common variant rs1017 is not associated with susceptibility to congenital heart disease in a Chinese population

BACKGROUND

ISL1, as a member of the LIM homeodomain transcription factor family, is expressed in a distinct population of undifferentiated cardiac progenitors and plays a pivotal role in cardiogenesis. Lacking ISL1 expression results in growth arrest or displays profound defects in heart development, including atria, ventricle, and the inflow and outflow tracts, which constitute a major form of congenital heart disease (CHD). Recently, an important study by Stevens et al. found that genetic variation in ISL1 is associated with risk of CHD in white and black/African American populations; this observation led us to hypothesize that ISL1 common variants might influence susceptibility to sporadic CHD in our Chinese population.

METHODS

We conducted a case-control study of CHD in Chinese to test our hypothesis by genotyping ISL1 common variant rs1017 in 1003 CHD cases and 1012 non-CHD controls.

RESULTS

We found that rs1017 was not associated with the risk of CHD (p=0.213). When we performed stratified analyses according to subjects' age, sex, and CHD classifications, we found no overall heterogeneity of risk in different subgroups.

CONCLUSIONS

This is the first study which indicates that ISL1 common variant rs1017 may not play a role in sporadic CHD susceptibility in the Chinese population.

Attenuation of microRNA-22 derepressed PTEN to effectively protect rat cardiomyocytes from hypertrophy

Cardiac hypertrophy, which is characterized by the enlargement of cell size, reactivation of fetal genes, remains one of the most important triggers to heart failure. Increasing evidence shows that microRNA (miRNA) is extensively involved in the pathogenesis of cardiac hypertrophy. But the effects of miRNAs on cardiomyocyte hypertrophy have not been completely solved yet. Here, we showed that a collection of miRNAs was aberrantly expressed in hypertrophic cardiomyocytes induced by phenylephrine (PE) or angiotensin II (Ang II). Among them, miR-22 was the most strikingly up-regulated miRNA. To investigate the role of miR-22 in hypertrophy, both over-expression and knock-down assays were performed on cardiomyocytes. The results showed that up-regulation of miR-22 significantly increased the cell size and markedly influenced the expression of hypertrophic markers, including induction of nppa and reduction of myh6. In contrast, reduction of miR-22 level attenuated either PE- or Ang II-induced hypertrophic reaction. Furthermore, several genes, including PTEN, were identified as potential targets of miR-22 by bioinformatic algorithms. Using luciferase analysis, miR-22 could significantly suppress the luciferase activity of reporter fused with 3' untranslated region of PTEN mRNA. Furthermore, up-regulation of miR-22 could suppress the protein level of PTEN and reduction of miR-22 level markedly increased the protein level of PTEN in cardiomyocytes by Western blot analysis, suggesting that the contribution of miR-22 to cardiomyocyte hypertrophy may be partially through targeting PTEN. Taken together, miRNAs were dynamically regulated in cardiomyocyte hypertrophy and attenuation of miR-22 in rat cardiomyocytes efficiently protected from hypertrophic effects through derepressing PTEN.

A miR-1207-5p binding site polymorphism abolishes regulation of HBEGF and is associated with disease severity in CFHR5 nephropathy

Heparin binding epidermal growth factor (HBEGF) is expressed in podocytes and was shown to play a role in glomerular physiology. MicroRNA binding sites on the 3′UTR of HBEGF were predicted using miRWalk algorithm and followed by DNA sequencing in 103 patients diagnosed with mild or severe glomerulopathy. A single nucleotide polymorphism, miRSNP C1936T (rs13385), was identified at the 3′UTR of HBEGF that corresponds to the second base of the hsa-miR-1207-5p seed region. When AB8/13 undifferentiated podocytes were transfected with miRNA mimics of hsa-miR-1207-5p, the HBEGF protein levels were reduced by about 50%. A DNA fragment containing the miRSNP allele-1936C was cloned into the pMIR-Report Luciferase vector and co-transfected with miRNA mimics of hsa-miR-1207-5p into AB8/13 podocytes. In agreement with western blot data, this resulted in reduced luciferase expression demonstrating the ability of hsa-miR-1207-5p to directly regulate HBEGF expression. On the contrary, in the presence of the miRSNP 1936T allele, this regulation was abolished. Collectively, these results demonstrate that variant 1936T of this miRSNP prevents hsa-miR-1207-5p from down-regulating HBEGF in podocytes. We hypothesized that this variant has a functional role as a genetic modifier. To this end, we showed that in a cohort of 78 patients diagnosed with CFHR5 nephropathy (also known as C3-glomerulopathy), inheritance of miRSNP 1936T allele was significantly increased in the group demonstrating progression to chronic renal failure on long follow-up. No similar association was detected in a cohort of patients with thin basement membrane nephropathy. This is the first report associating a miRSNP as genetic modifier to a monogenic renal disorder.

A micro-ribonucleic acid signature associated with recovery from assist device support in 2 groups of patients with severe heart failure

OBJECTIVES

This study was conducted to test the hypothesis that cardiac micro-ribonucleic acid (miR) profiling in severe heart failure patients at the time of ventricular assist device (VAD) placement would differentiate those who remained VAD-dependent from those with subsequent left ventricular (LV) recovery.

BACKGROUND

The relationship of myocardial miR expression to ventricular recovery is unknown.

METHODS

We studied 28 patients with nonischemic cardiomyopathy requiring VAD support consisting of test and validation cohorts from 2 institutions: 14 with subsequent LV recovery and VAD removal and 14 clinically matched VAD-dependent patients. Apical core myocardium was studied for expression of 376 miRs by polymerase chain reaction (PCR) array and real-time-PCR methods. Samples from 7 nonfailing hearts were used in confirmatory studies.

RESULTS

By PCR array, 10 miRs were differentially expressed between LV recovery and VAD-dependent patients in the test cohort. The real-time PCR confirmed lower expression in LV recovery patients for 4 miRs (15b, -1.5-fold; 23a, -2.2-fold; 26a, -1.4-fold; and 195, -1.8-fold; all p < 0.04 vs. VAD dependent). The validation cohort similarly showed lower miRs expression in LV recovery patients (23a, -1.8-fold; and 195, -1.5-fold; both p < 0.03). Furthermore, miR 23a and 195 expression in nonfailing hearts was similar to LV recovery patients (both p < 0.04 vs. VAD dependent). The LV recovery patients also had significantly smaller cardiomyocytes by quantitative histology in both cohorts.

CONCLUSIONS

Lower cardiac expression of miRs 23a and 195 and smaller cardiomyocyte size at the time of VAD placement were associated with subsequent LV functional recovery. Differential expression of miRs at VAD placement may provide markers to assess recovery potential.

Association study of microRNA polymorphisms with risk of idiopathic recurrent spontaneous abortion in Korean women

AIM

The aim of this study was to investigate the association of microRNA polymorphisms (miR-146aC>G, miR-149T>C, miR-196a2T>C, and miR-499A>G) in Korean patients with recurrent spontaneous abortion (RSA).

METHODS

We conducted a case-control study of 564 Korean women: 330 patients with at least two unexplained consecutive pregnancy losses and 234 healthy controls with at least one live birth and no history of pregnancy loss.

RESULTS

RSA patients exhibited significantly different frequencies of the miR-196a2CC (TT+TC vs. CC; adjusted odds ratio [AOR], 1.587; 95% confidence interval [CI], 1.042–2.417) and miR-499AG+GG genotypes (AOR, 1.587; 95% CI, 1.096–2.298) [corrected] compared with the control group. The combination of miR-196a2CC and miR-499AG+GG showed synergistic effects (AOR, 3.541; 95% CI, 1.645–7.624).

CONCLUSION

miR-196a2CC, miR-499AG+GG, and the miR-196a2CC/miR-499AG+GG combination are significantly associated with idiopathic RSA in Korean women.

Natural variation in biogenesis efficiency of individual Arabidopsis thaliana microRNAs

Like protein-coding genes, loci that produce microRNAs (miRNAs) are generally considered to be under purifying selection, consistent with miRNA polymorphisms being able to cause disease. Nevertheless, it has been hypothesized that variation in miRNA genes may contribute to phenotypic diversity. Here we demonstrate that a naturally occurring polymorphism in the MIR164A gene affects leaf shape and shoot architecture in Arabidopsis thaliana, with the effects being modified by additional loci in the genome. A single base pair substitution in the miRNA complementary sequence alters the predicted stability of the miRNA:miRNA(∗) duplex. It thereby greatly reduces miRNA accumulation, probably because it interferes with precursor processing. We demonstrate that this is not a rare exception and that natural strains of Arabidopsis thaliana harbor dozens of similar polymorphisms that affect processing of a wide range of miRNA precursors. Our results suggest that natural variation in miRNA biogenesis resulting from cis mutations is a common contributor to phenotypic variation in plants.

Polymorphisms of miRNAs genes are associated with the risk and prognosis of coronary artery disease

BACKGROUND

MicroRNAs (miRNAs) are small, single-stranded, non-protein-coding RNAs of about 22 nucleotides. miRNA molecules have been identified that plays key roles in a broad range of physiologic and pathologic processes. Polymorphisms in the corresponding sequence space are likely to make a significant contribution to phenotypic variation.

METHODS AND RESULTS

To assess the variations of rs11614913 T → C in hsa-mir-196a2 and rs3746444 A → G in hsa-mir-499 in the complex etiology of coronary artery disease (CAD), 956 CAD patients diagnosed by coronary arterial angiography and 620 controls were enrolled. Among the patients, 785 (785/956) had complete follow-ups for 42 months. The variant genotypes CC/CT of hsa-mir-196a2 rs11614913 T → C were not associated with a significantly increased risk of CAD (adjusted OR = 1.02, 95% CI = 0.76-1.38), compared with wide genotype TT, but CC and CC/CT genotypes were associated with 34 and 35% increased risks of serious prognosis of CAD (adjusted HR = 1.34, 95% CI = 1.02-1.75 for CC; adjusted HR = 1.35, 95% CI = 1.03-1.75 for CC/CT). In the variant of hsa-mir-499 rs3746444A → G, GG was associated with the 223% increased risk of CAD (adjusted OR = 3.23, 95% CI = 1.56-6.67). Cox regression analysis showed that age, smoking status, numbers of pathological changes in coronary arteries, rs11614913 T → C, and diabetes mellitus were associated with serious prognosis of CAD.

CONCLUSION

Our findings strongly implicate the functional miRNAs polymorphisms of hsa-mir-196a2 and hsa-mir-499 genes may modulate the occurrence or prognosis in Chinese CAD.

Association of the miR-146aC>G, 149C>T, 196a2C>T, and 499A>G polymorphisms with colorectal cancer in the Korean population

MicroRNAs (miRNAs) are small, 18- to 22-nucleotide non-coding RNAs that regulate target gene expression. Although recent studies focused on various diseases that harbor the miR-146aC>G (rs2910164), 149C>T (rs2292832), 196a2C>T (rs11614913), and 499A>G (rs3746444) polymorphisms, the role of miRNA genetic variants in colorectal cancer is still unknown. The present study aimed to evaluate the role of four miRNA polymorphisms in patients with colorectal cancer. We enrolled 446 colorectal cancer patients and 502 control subjects from the Korean population. We found a significantly increased colorectal cancer risk with the miR-196a2CC genotype compared with the TT/CT genotype (AOR = 1.50; 95% CI = 1.11-2.04; P = 0.01; FDR-P = 0.04). In the stratified analyses, we observed both weak and strong association data. We found stronger associations of the miR-196a2 variants in the non-diabetic and rectal cancer groups than other stratified groups. Our data suggest that the miRNA variants could affect the development of colorectal cancer in the Korean population.

A functional variant in microRNA-196a2 is associated with susceptibility of colorectal cancer in a Chinese population

BACKGROUND AND AIMS

MicroRNAs (miRNA) can act as oncogenes or tumor suppressors. Polymorphisms present in pri-, pre- and mature miRNAs can potentially modulate the expression of hundreds of genes, broadly affecting miRNA function. Notably, the rs11614913 SNP in miR-196a2 has been implicated in carcinogenesis, but its association with colorectal cancer (CRC) remains unexplored. We performed a case-control study to investigate the genetic association between this functional SNP and CRC susceptibility and progression.

METHODS

We genotyped the rs11614913 SNP in 252 CRC patients and 543 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In addition, we examined miR-196a expression level in colorectal cancer tissues (n = 50) obtained from the studied CRC patients.

RESULTS

Frequency of the CC genotype was higher in CRC patients than controls, implying that the subjects with the CC genotype or C allele containing genotypes (CT and CC) have a higher risk of CRC. However, no significant association between this polymorphism and CRC progression was observed. Expression analysis revealed that rs11614913 CC or carrying at least one C allele was associated with a significantly increased level of mature miR-196a (p = 0.010 or = 0.022).

CONCLUSIONS

The present study provides the first evidence that miR-196a2 polymorphism may contribute to CRC susceptibility in a Chinese population through modulating mature miR-196a expression.

Association between microRNA196a2 rs11614913 genotypes and the risk of non-small cell lung cancer in Korean population

Objectives

The microRNA (miRNA) miR-196a2 may play an important role in lung cancer development and survival by altering binding activity of target mRNA. In this study, we evaluated their associations with the susceptibility of non-small cell lung cancers (NSCLC) by case-control study in a Korean population.

Methods

We performed genotyping analyses for miR-196a2 rs11614913 T/C at miRNA regions in a case-control study using blood samples of 406 NSCLC patient and 428 cancer-free control groups.

Results

The total C allele frequencies for miR-196a2 were 48.8% for the patients and 45.6% for the controls; and the genotype frequencies of TT, TC, and CC were 23.7%, 55.2%, and 21.1% for the patients and 31.1%, 46.35%, and 22.4% for the controls (p<0.05). Participants who possesses TC/CC genotypes showed high risk for NSCLC compared to those possessed TT genotypes (OR, 1.42; 95% CI, 1.03 to 1.96). The association was persisted in 60 and older age group, male, smokers, those without family history for cancer. However, no significant association of CC genotypes in recessive genetic model was observed.

Conclusions

In conclusion, this case-control study provides evidence that miR-196a2 rs11614913 C/T polymorphisms are associated with a significantly increased risk of NSCLC in a dominant model, indicating that common genetic polymorphisms in miR-196a2 rs11614913 are associated with NSCLC. The association of miR196a2 rs11614913 polymorphisms and NSCLC risk require confirmation through additional larger studies.

Genetic variants in miR-146a, miR-149, miR-196a2, miR-499 and their influence on relative expression in lung cancers

BACKGROUND

The presence of sequence variants in miRNA genes may influence their processing, expression and binding to target mRNAs. Since single miRNA can have a large number of potential mRNA targets, even minor variations in its expression can have influences on hundreds of putative mRNAs.

METHODS

Here, we evaluated 101 paired samples (cancer and normal tissues) from non-small cell lung carcinoma (NSCLC) patients to study the genotype distribution of single nucleotide polymorphisms (SNPs) in miR-146a (rs2910164 C-G), miR-149 (rs2292832 C-T), miR-196a2 (rs11614913 C-T) and miR-499 (rs3746444 G-A) and their influence on the expression of respective miRNAs.

RESULTS

Relative expression of miR-146a, miR-149 and miR-499 were comparable in NSCLC and in paired control tissues. On the contrary, we clearly detected a significant increase (p<0.001) of miR-196a2 expression in NSCLC. In particular we found a significant association between miR-196a2 CC genotype and high expression, whereas TT geno-type showed a very low expression in comparison to both CT (p<0.005) and CC patients (p<0.01). We did not find any association between miR-149, miR-196a2 and miR-499 genotype and risk of NSCLC. Conversely, CG genotype of miR-146a appeared associated to an increased risk for NSCLC (p=0.042 and 1.77 OR).

CONCLUSIONS

Our results seem to demonstrate that sequence variants of miR-196a2 can have an influence on its expression, while miR-146a can have a role in increasing the risk of NSCLC.

Prognostic significance of microRNA gene polymorphisms in patients with surgically resected colorectal cancer

MicroRNAs (miRNAs) are small 19- to 22-nucleotide sequences of RNA that participate in the regulation of cell differentiation, cell cycle progression and apoptosis. Although single-nucleotide polymorphisms (SNPs) in miRNA regions are considered unlikely to be functionally important, nucleotide variations within the sequences of primary (pri)- or precursor (pre)-miRNAs may affect miRNA processing and ultimately result in the modification of miRNA expression. The aim of this study was to investigate associations between four SNPs in pre-miRNA genes and the survival of colorectal cancer patients. A total of 407 colorectal patients were consecutively enrolled. DNA was extracted from blood specimens, and the hsa-mir-146aC>G, hsa-mir-149C>T, hsa-mir-196a2C>T and hsa-mir-499A>G polymorphisms were genotyped by PCR-RFLP. We were unable to identify independent prognostic SNPs for colorectal cancer. However, the heterozygous TC genotype of the 196a2C>T polymorphism was a significant risk factor for the overall survival of rectal cancer patients (HR=3.554, 95% CI 1.296-9.747, p=0.014). Further large-population studies are warranted to define the 196a2C>T polymorphism as a prognostic factor of rectal cancer.

Association between single-nucleotide polymorphisms in pre-miRNAs and the risk of asthma in a Chinese population

Single-nucleotide polymorphisms (SNPs) in pre-miRNAs may alter microRNA (miRNA) expression levels or processing and contribute to susceptibility to a wide range of diseases. We investigated the correlation between four SNPs (rs11614913, rs3746444, rs2910164, and rs229283) in pre-miRNAs and the risk of asthma in 220 asthma patients and 540 controls using polymerase chain reaction-restriction fragment length polymorphism methodology and DNA-sequencing. There were significant differences in the genotype and allelic distribution of rs2910164G/C and rs2292832C/T polymorphisms among cases and controls. The CC genotype and C allele of rs2910164G/C were significantly associated with a decreased risk of asthma (CC vs. GG, odds ratio [OR] = 0.51, 95% confidence interval [CI]: 0.31-0.82; C vs. G, OR = 0.74, 95% CI: 0.59-0.93). Similarly, the TT genotype and T allele of rs2292832C/T were significantly associated with a decreased risk of asthma (TT vs. CC, OR = 0.56, 95% CI: 0.33-0.95; T vs. C, OR = 0.71, 95% CI: 0.53-0.95). However, no significant association between the other two polymorphisms (i.e., rs11614913C/T and rs3746444C/T) and the risk of asthma was observed. Our data indicate that rs2910164G/C and rs2292832C/T may play a role in the development of asthma.