Regulation and function of miRNA-21 in health and disease

MiR-21-5p and miR-126a-3p levels in plasma and circulating angiogenic cells: relationship with type 2 diabetes complications

Innovative biomarkers are required to manage type 2 diabetic patients (T2DM). We focused our study on miR-126-3p and miR-21-5p levels, as biomarkers of endothelial function and inflammation. MiRNAs levels were measured in plasma from 107 healthy subjects (CTR) and 193 diabetic patients (T2DM), 76 without (T2DM NC) and 117 with (T2DM C) complications.

When diabetic complication were analysed as a whole, miR-126-3p and miR-21-5p levels declined significantly from CTR to T2DM NC and T2DM C patients. When miRNAs levels were related to specific complications, significantly higher miR-21-5p levels (0.46 ± 0.44 vs. 0.26±0.33, p < 0.001) and significant lower miR-126-3p levels (0.21±0.21 vs. 0.28±0.22, p = 0.032) were found in T2DM with previous major cardiovascular events (MACE) vs. all the others T2DM patients.

To confirm these results we focused on circulating angiogenic cells (CACs) from a subgroup of 10 CTR, 15 T2DM NC and 15 T2DM patients with MACE. CACs from T2DM patients expressed higher miR-21-5p and lower miR-126-3p levels than CACs from CTR. Furthermore, CACs from T2DM + MACE showed the highest levels of miR-21-5p.

Circulating miR-21-5p and miR-126-3p emerge as dynamic biomarkers of systemic inflammatory/angiogenic status. Their expression levels in CACs from T2DM with MACE suggest a shift from a proangiogenic to a proinflammatory profile.

DNA damage response (DDR) and senescence: shuttled inflamma-miRNAs on the stage of inflamm-aging

A major issue in aging research is how cellular phenomena affect aging at the systemic level. Emerging evidence suggests that DNA damage response (DDR) signaling is a key mechanism linking DNA damage accumulation, cell senescence, and organism aging. DDR activation in senescent cells promotes acquisition of a proinflammatory secretory phenotype (SASP), which in turn elicits DDR and SASP activation in neighboring cells, thereby creating a proinflammatory environment extending at the local and eventually the systemic level. DDR activation is triggered by genomic lesions as well as emerging bacterial and viral metagenomes. Therefore, the buildup of cells with an activated DDR probably fuels inflamm-aging and predisposes to the development of the major age-related diseases (ARDs). Micro (mi)-RNAs - non-coding RNAs involved in gene expression modulation - are released locally and systemically by a variety of shuttles (exosomes, lipoproteins, proteins) that likely affect the efficiency of their biological effects. Here we suggest that some miRNAs, previously found to be associated with inflammation and senescence - miR-146, miR-155, and miR-21 - play a central role in the interplay among DDR, cell senescence and inflamm-aging. The identification of the functions of shuttled senescence-associated miRNAs is expected to shed light on the aging process and on how to delay ARD development.

HER2-encoded mir-4728 forms a receptor-independent circuit with miR-21-5p through the non-canonical poly(A) polymerase PAPD5

We previously reported that the human HER2 gene encodes the intronic microRNA mir-4728, which is overexpressed together with its oncogenic host gene and may act independently of the HER2 receptor. More recently, we also reported that the oncogenic miR-21-5p is regulated by 3' tailing and trimming by the non-canonical poly(A) polymerase PAPD5 and the ribonuclease PARN. Here we demonstrate a dual function for the HER2 locus in upregulation of miR-21-5p; while HER2 signalling activates transcription of mir-21, miR-4728-3p specifically stabilises miR-21-5p through inhibition of PAPD5. Our results establish a new and unexpected oncogenic role for the HER2 locus that is not currently being targeted by any anti-HER2 therapy.

Serum microRNA-21 expression as a prognostic and therapeutic biomarker for breast cancer patients

MiRNA-21 is recognized as the main active candidate and high expression in many solid tumors consequential cell proliferation, differentiation, apoptosis, and closely related to metastasis of disease. The study aimed to evaluate the serum miRNA-21 expression and therapy outcome in breast cancer patients and cell lines. Seventy-five histopathologically confirmed newly diagnosed breast cancer patients were included in the study; before and after therapy, patient's blood sample were collected and analyzed for serum microRNA-21 expression by quantitative real-time PCR. In patients, 8.9 mean fold increased microRNA-21 expression was observed compared to controls. Increased expression was found to be associated with advanced stage (11.72-fold), lymph node involvement (11.12-fold), and distant metastases (20.17-fold). After treatment significant decrease in miRNA-21 expression was observed and found to be significant (p < 0.0001). Patients treated with neoadjuvant therapy had significant impact on miRNA-21 suppression and found to be significantly associated with different clinicopathological features of patients. Increased miRNA-21 expression was also found to be significantly associated with poor survival of breast cancer patients (p = 0.002). MicroRNA-21 expression could be used as promising predictive indicators for breast cancer prognosis. MicroRNA-21 over-expression was associated with response to neoadjuvant therapy and may perhaps be considered as primary treatment choice.

Airway Secretory microRNAome Changes during Rhinovirus Infection in Early Childhood

BACKGROUND

Innate immune responses are fine-tuned by small noncoding RNA molecules termed microRNAs (miRs) that modify gene expression in response to the environment. During acute infections, miRs can be secreted in extracellular vesicles (EV) to facilitate cell-to-cell genetic communication. The purpose of this study was to characterize the baseline population of miRs secreted in EVs in the airways of young children (airway secretory microRNAome) and examine the changes during rhinovirus (RV) infection, the most common cause of asthma exacerbations and the most important early risk factor for the development of asthma beyond childhood.

METHODS

Nasal airway secretions were obtained from children (≤3 yrs. old) during PCR-confirmed RV infections (n = 10) and age-matched controls (n = 10). Nasal EVs were isolated with polymer-based precipitation and global miR profiles generated using NanoString microarrays. We validated our in vivo airway secretory miR data in an in vitro airway epithelium model using apical secretions from primary human bronchial epithelial cells (HBEC) differentiated at air-liquid interface (ALI). Bioinformatics tools were used to determine the unified (nasal and bronchial) signature airway secretory miRNAome and changes during RV infection in children.

RESULTS

Multiscale analysis identified four signature miRs comprising the baseline airway secretory miRNAome: hsa-miR-630, hsa-miR-302d-3p, hsa- miR-320e, hsa-miR-612. We identified hsa-miR-155 as the main change in the baseline miRNAome during RV infection in young children. We investigated the potential biological relevance of the airway secretion of hsa-mir-155 using in silico models derived from gene datasets of experimental in vivo human RV infection. These analyses confirmed that hsa-miR-155 targetome is an overrepresented pathway in the upper airways of individuals infected with RV.

CONCLUSIONS

Comparative analysis of the airway secretory microRNAome in children indicates that RV infection is associated with airway secretion of EVs containing miR-155, which is predicted in silico to regulate antiviral immunity. Further characterization of the airway secretory microRNAome during health and disease may lead to completely new strategies to treat and monitor respiratory conditions in all ages.

MiR-21-5p Links Epithelial-Mesenchymal Transition Phenotype with Stem-Like Cell Signatures via AKT Signaling in Keloid Keratinocytes

Keloid is the abnormal wound healing puzzled by the aggressive growth and high recurrence rate due to its unrevealed key pathogenic mechanism. MicroRNAs contribute to a series of biological processes including epithelial-mesenchymal transition (EMT) and cells stemness involved in fibrotic disease. Here, using microRNAs microarray analysis we found mir-21-5p was significantly up-regulated in keloid epidermis. To investigate the role of miR-21-5p in keloid pathogenesis, we transfected miR-21-5p mimic or inhibitor in keloid keratinocytes and examined the abilities of cell proliferation, apoptosis, migration and invasion, the expressions of EMT-related markers vimentin and E-cadherin and stem-like cells-associated markers CD44 and ALDH1, and the involvement of PTEN and the signaling of AKT and ERK. Our results demonstrated that up-regulation or knockdown of miR-21-5p significantly increased or decreased the migration, invasion and sphere-forming abilities of keloid keratinocytes, and the phenotype of EMT and cells stemness were enhanced or reduced as well. Furthermore, PTEN and p-AKT were shown to participate in the regulation of miR-21-5p on EMT phenotypes and stemness signatures of keloid keratinocytes, which might account for the invasion and recurrence of keloids. This molecular mechanism of miR-21-5p on keloid keratinocytes linked EMT with cells stemness and implicated novel therapeutic targets for keloids.

Serum extracellular vesicular miR-21-5p is a predictor of the prognosis in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a disease with a poor prognosis. Although the median survival is 3 years, the clinical course varies to a large extent among IPF patients. To date, there has been no definitive prognostic marker. Extracellular vesicles (EVs) are known to hold nucleic acid, including microRNAs, and to regulate gene expression in the recipient cells. Moreover, EVs have been shown to express distinct surface proteins or enveloped microRNAs depending on the parent cell or pathological condition. We aimed to identify serum EV microRNAs that would be prognostic for IPF.

Methods

To determine target microRNAs in IPF, we measured serum EV microRNA expression profiles using microRNA PCR arrays in a bleomycin mouse model and validated the microRNAs in additional mice using RT-PCR. Secondly, we enrolled 41 IPF patients and conducted a 30-month prospective cohort study. Expression of serum EV miR-21-5p was normalized by dividing by the EV amount. The relative amount of EVs was measured using the ExoScreen method. We calculated the correlations between baseline serum EV miR-21-5p expression and other clinical variables. Furthermore, we determined if serum EV miR-21-5p can predict mortality during 30 months using the Cox hazard model. According to the median level, we divided the IPF patients into two groups. Then we compared the survival rate during 30 months between the two groups using the Kaplan-Meier method.

Results

Serum EV miR-21-5p was elevated in both the acute inflammatory phase (day 7) and the chronic fibrotic phase (day 28) in the mouse model. In the clinical setting, serum EV miR-21-5p was significantly higher in IPF patients than in healthy control subjects. The baseline serum EV miR-21-5p was correlated with the rate of decline in vital capacity over 6 months. Furthermore, serum EV miR-21-5p was independently associated with mortality during the following 30 months, even after adjustment for other variables. In the survival analysis, IPF patients whose baseline serum EV miR-21-5p was high had a significantly poorer prognosis over 30 months.

Conclusions

Our results suggest that serum EV miR-21-5p has potential as a prognostic biomarker for IPF.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0427-3) contains supplementary material, which is available to authorized users.

Serum miR-21, miR-26a and miR-101 as potential biomarkers of hepatocellular carcinoma

AIM

This study aimed to investigate the expressions of serum miR-21, miR-26a and miR-101 in hepatocellular carcinoma (HCC) and their diagnostic value.

METHODS

Serum levels of miR-21, miR-26a and miR-101 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) in 52 HCC patients, 42 chronic hepatitis (CH) patients and 43 healthy controls. ROC curve analysis was performed to evaluate the diagnostic value. Clinical parameters were collected.

RESULTS

Serum level of miR-21 was higher while miR-26a and miR-101 were significantly lower in HCC patients than those in healthy controls (P<0.05, P<0.001 and P<0.05, respectively). Serum levels of miR-26a and miR-101 were significantly lower in HCC patients than those in CH patients (P<0.001 and P<0.05). ROC curve analyses revealed that miR-21, miR-26a and miR-101 could differentiate HCC patients from healthy controls, the area under ROC curve (AUC) were 0.621 (67.4% sensitivity and 55.8% specificity), 0.754 (51.9% sensitivity and 95.2% specificity) and 0.631 (47.1% sensitivity and 81% specificity), respectively. Combination of miRNAs and alpha-fetoprotein (AFP) yielded an AUC of 0.914 with 87.0% sensitivity and 78.0% specificity. miR-26a and miR-101 had diagnostic potential for differentiating HCC from CH with AUC of 0.762 (75% sensitivity and 70% specificity) and 0.623 (54.9% sensitivity and 76.9% specificity). Combination of miR-26a, miR-101 and AFP yielded an improved AUC than AFP alone (0.854 vs. 0.683). Notably, miR-26a could differentiate small tumors HCC (≤3cm) from CH with an AUC of 0.753 (80% sensitivity and 62.5% specificity).

CONCLUSIONS

Serum miR-21, miR-26a and miR-101 are deregulated in HCC and can serve as potential biomarkers. Combination of these miRNAs and AFP provide a better detection than AFP alone. Serum miR-26a is a promising biomarker for early detection of HCC.

High copy number variation of cancer-related microRNA genes and frequent amplification of DICER1 and DROSHA in lung cancer

A growing body of evidence indicates that miRNAs may be a class of genetic elements that can either drive or suppress oncogenesis. In this study we analyzed the somatic copy number variation of 14 miRNA genes frequently found to be either over- or underexpressed in lung cancer, as well as two miRNA biogenesis genes, DICER1 and DROSHA, in non-small-cell lung cancer (NSCLC). Our analysis showed that most analyzed miRNA genes undergo substantial copy number alteration in lung cancer. The most frequently amplified miRNA genes include the following: miR-30d, miR-21, miR-17 and miR-155. We also showed that both DICER1 and DROSHA are frequently amplified in NSCLC. The copy number variation of DICER1 and DROSHA correlates well with their expression and survival of NSCLC and other cancer patients. The increased expression of DROSHA and DICER1 decreases and increases the survival, respectively. In conclusion, our results show that copy number variation may be an important mechanism of upregulation/downregulation of miRNAs in cancer and suggest an oncogenic role for DROSHA.

Identification of a novel PPARβ/δ/miR-21-3p axis in UV-induced skin inflammation

Although excessive exposure to UV is widely recognized as a major factor leading to skin perturbations and cancer, the complex mechanisms underlying inflammatory skin disorders resulting from UV exposure remain incompletely characterized. The nuclear hormone receptor PPARβ/δ is known to control mouse cutaneous repair and UV-induced skin cancer development. Here, we describe a novel PPARβ/δ-dependent molecular cascade involving TGFβ1 and miR-21-3p, which is activated in the epidermis in response to UV exposure. We establish that the passenger miRNA miR-21-3p, that we identify as a novel UV-induced miRNA in the epidermis, plays a pro-inflammatory function in keratinocytes and that its high level of expression in human skin is associated with psoriasis and squamous cell carcinomas. Finally, we provide evidence that inhibition of miR-21-3p reduces UV-induced cutaneous inflammation in ex vivo human skin biopsies, thereby underlining the clinical relevance of miRNA-based topical therapies for cutaneous disorders.

Plasma-specific microRNA response induced by acute exposure to aristolochic acid I in rats

Aristolochic acid I (AAI) derived from a natural herbal alkaloid is a nephrotoxicant. AAI-induced acute kidney injury (AKI), a devastating clinical disease associated with high mortality rates, is difficult for early diagnosis. To address this issue, we identified and validated early-detection biomarkers for AAI-induced acute kidney injury via profiling microRNA expression in rats. Global miRNA expression profile analysis found that 21 miRNAs were significantly dysregulated in kidney of rats treated by 40 mg/kg AAI on day 2, day 4, or day 6, among which 5 miRNAs were upregulated at all three time points. Quantitative RT-PCR confirmed that miR-21-3p on day 4 and day 6 was obviously upregulated in kidney of rats treated by 40 mg/kg AAI. Further examination found that miR-21-3p was increased in plasma early on day 2 in 10 mg/kg AAI-treated rats, but not in non-target organs. Importantly, the elevation of plasma miR-21-3p preceded the increase in blood urea nitrogen and creatinine, and the presence of renal tubular injury, characterized by differential increase before and after the presence of renal tubular lesions. Our findings thus show that miRNA expression is upregulated in kidney and plasma of AKI rat induced by AAI, and plasma miR-21-3p may be served as a new potential biomarker for early diagnosing AAI-induced acute kidney injury in rats, and possibly in humans.

Simultaneous inhibition of multiple oncogenic miRNAs by a multi-potent microRNA sponge

The roles of oncogenic miRNAs are widely recognized in many cancers. Inhibition of single miRNA using antagomiR can efficiently knock-down a specific miRNA. However, the effect is transient and often results in subtle phenotype, as there are other miRNAs contribute to tumorigenesis. Here we report a multi-potent miRNA sponge inhibiting multiple miRNAs simultaneously. As a model system, we targeted miR-21, miR-155 and miR-221/222, known as oncogenic miRNAs in multiple tumors including breast and pancreatic cancers. To achieve efficient knockdown, we generated perfect and bulged-matched miRNA binding sites (MBS) and introduced multiple copies of MBS, ranging from one to five, in the multi-potent miRNA sponge. Luciferase reporter assay showed the multi-potent miRNA sponge efficiently inhibited 4 miRNAs in breast and pancreatic cancer cells. Furthermore, a stable and inducible version of the multi-potent miRNA sponge cell line showed the miRNA sponge efficiently reduces the level of 4 target miRNAs and increase target protein level of these oncogenic miRNAs. Finally, we showed the miRNA sponge sensitize cells to cancer drug and attenuate cell migratory activity. Altogether, our study demonstrates the multi-potent miRNA sponge is a useful tool to examine the functional impact of simultaneous inhibition of multiple miRNAs and proposes a therapeutic potential.

Comprehensive identification and profiling of Nile tilapia (Oreochromis niloticus) microRNAs response to Streptococcus agalactiae infection through high-throughput sequencing

MicroRNAs are a kind of small non-coding RNAs that participate in various biological processes. Deregulated microRNA expression is associated with several types of diseases. Tilapia (Oreochromis niloticus) is an important commercial fish species in China. To identify miRNAs and investigate immune-related miRNAs of O. niloticus, we applied high-throughput sequencing technology to identify and analyze miRNAs from tilapia infected with Streptococcus agalactiae at a timescale of 72 h divided into six different time points. The results showed that a total of 3009 tilapia miRNAs were identified, including in 1121 miRNAs which have homologues in the currently available databases and 1878 novel miRNAs. The expression levels of 218 tilapia miRNAs were significantly altered at 6 h-72 h post-bacterial infection (pi), and these miRNAs were therefore classified as differentially expressed tilapia miRNAs. For the 1121 differentially expressed tilapia miRNAs target 41961 genes. GO and KEGG enrichment analysis revealed that some target genes of tilapia miRNAs were grouped mainly into the categories of apoptotic process, signal pathway, and immune response. This is the first report of comprehensive identification of O. niloticus miRNAs being differentially regulated in spleen in normal conditions relating to S. agalactiae infection. This work provides an opportunity for further understanding of the molecular mechanisms of miRNA regulation in O. niloticus host-pathogen interactions.

Elastic band resistance training influences transforming growth factor-ß receptor I mRNA expression in peripheral mononuclear cells of institutionalised older adults: the Vienna Active Ageing Study (VAAS)

Background

Ageing, inactivity and obesity are associated with chronic low-grade inflammation contributing to a variety of lifestyle-related diseases. Transforming growth factor-β (TGF-β) is a multimodal protein with various cellular functions ranging from tissue remodelling to the regulation of inflammation and immune functions. While it is generally accepted that aerobic exercise exerts beneficial effects on several aspects of immune functions, even in older adults, the effect of resistance training remains unclear. The aim of this study was to investigate whether progressive resistance training (6 months) with or without nutritional supplementation (protein and vitamins) would influence circulating C-reactive protein and TGF-β levels as well as TGF-β signalling in peripheral mononuclear cells (PBMCs) of institutionalised adults with a median age of 84.5 (65.0–97.4) years.

Results

Elastic band resistance training significantly improved performance as shown by the arm-lifting test (p = 0.007), chair stand test (p = 0.001) and 6-min walking test (p = 0.026). These results were paralleled by a reduction in TGF-β receptor I (TGF-βRI) mRNA expression in PBMCs (p = 0.006), while circulating inflammatory markers were unaffected. Protein and vitamin supplementation did not provoke any additional effects. Interestingly, muscular endurance of upper and lower body and aerobic performance at baseline were negatively associated with changes in circulating TGF-β at the early phase of the study. Furthermore, drop-outs of the study were characterised not only by lower physical performance but also higher TGF-β and TGF-βRI mRNA expression, and lower miRNA-21 expression.

Conclusions

Progressive resistance training with elastic bands did not influence chronic low-grade inflammation but potentially affected TGF-β signalling in PBMCs through altered TGF-βRI mRNA expression. There appears to be an association between physical performance and TGF-β expression in PBMCs of older adults, in which the exact mechanisms need to be clarified.

Familial adenomatous patients with desmoid tumours show increased expression of miR-34a in serum and high levels in tumours

Familial adenomatous polyposis (FAP) is rare affecting 1 in 10,000 people and a subset (10%) are at risk of myofibroblastic desmoid tumours (DTs) after colectomy to prevent cancer. DTs are a major cause of morbidity and mortality. The absence of markers to monitor progression and a lack of treatment options are significant limitations to clinical management. We investigated microRNAs (miRNA) levels in DTs and serum using expression array analysis on two independent cohorts of FAP patients (total, n=24). Each comprised equal numbers of patients who had formed DTs (cases) and those who had not (controls). All controls had absence of DTs confirmed by clinical and radiological assessment over at least three years post- colectomy. Technical qPCR validation was performed using an expanded cohort (29 FAP patients; 16 cases and 13 controls). The most significant elevated serum miRNA marker of DTs was miR-34a-5p and in-situ hybridisation (ISH) showed most DTs analysed (5/6) expressed miRNA-34a-5p. Exome sequencing of tumour and matched germline DNA did not detect mutations within the miR-34a-5p transcript sites or 3′-UTR of target genes that would alter functional miRNA activity. In conclusion, miR-34a-5p is a potential circulatory marker and therapy target. A large prospective world-wide multi-centre study is now warranted.

Targeting microRNAs as key modulators of tumor immune response

The role of immune response is emerging as a key factor in the complex multistep process of cancer. Tumor microenvironment contains different types of immune cells, which contribute to regulate the fine balance between anti and protumor signals. In this context, mechanisms of crosstalk between cancer and immune cells remain to be extensively elucidated. Interestingly, microRNAs (miRNAs) have been demonstrated to function as crucial regulators of immune response in both physiological and pathological conditions. Specifically, different miRNAs have been reported to have a role in controlling the development and the functions of tumor-associated immune cells. This review aims to describe the most important miRNAs acting as critical modulators of immune response in the context of different solid tumors. In particular, we discuss recent studies that have demonstrated the existence of miRNA-mediated mechanisms regulating the recruitment and the activation status of specific tumor-associated immune cells in the tumor microenvironment. Moreover, various miRNAs have been found to target key cancer-related immune pathways, which concur to mediate the secretion of immunosuppressive or immunostimulating factors by cancer or immune cells. Modalities of miRNA exchange and miRNA-based delivery strategies are also discussed. Based on these findings, the modulation of individual or multiple miRNAs has the potential to enhance or inhibit specific immune subpopulations supporting antitumor immune responses, thus contributing to negatively affect tumorigenesis. New miRNA-based strategies can be developed for more effective immunotherapeutic interventions in cancer.

Human papillomavirus 16 E6 modulates the expression of host microRNAs in cervical cancer

OBJECTIVE

Human papillomavirus (HPV) infection is a prerequisite of developing cervical cancer, approximately half of which are associated with HPV type 16. There are reports that HPV can disturb the expression pattern of host miRNAs, but its mechanism is not well understood.

MATERIALS AND METHODS

In this study, we scanned 11 tumorigenesis related miRNAs in Hela cells that were overexpressed with HPV type 16 E6 protein.

RESULTS

We found the expression of miR-21 was upregulated by HPV type 16 E6 protein and meanwhile, the expression of miR-27a and miR-218 was downregulated. Furthermore, we identified that miR-21 overexpression could promote Hela and U2OS cells proliferation by targeting phosphatase-tensin homolog (PTEN), the result of which can be rescued by miR-21 inhibitor. In addition, E6 overexpression could also promote Hela cell migration and invasion.

CONCLUSION

Our results indicate that HPV infection and subsequent transformation take place through complex regulatory patterns of gene expression in the host cells, part of which are regulated by the E6 protein.

Export of microRNAs: A Bridge between Breast Carcinoma and Their Neighboring Cells

Breast cancer is a leading type of cancer among women in India as well as worldwide. According to the WHO 2015 report, it has been anticipated that there would be a twofold rise in the death due to breast cancer among women. The heterogeneous property of breast carcinoma has been suggested to be linked with dedicated set of communication and signaling pathway with their surroundings, which culminate into progression and development of the cancer. Among the plethora of communication tools in the hand of breast carcinoma cells is the recently appreciated exocytosis of the tightly packed short non-coding RNA molecules, predominantly the microRNAs (miRNAs). Recent studies suggest that miRNAs may work as courier messengers to participate in endocrine and paracrine signaling to facilitate information transfer between breast carcinoma and their neighboring cells. Evidence suggests that breast tumor cells communicate via packaged miRNAs in the tumor-released microvesicles, which enrich the tumor microenvironment. There is a strong view that dissecting out the mechanistic and regulatory aspects of miRNA export and role may uncover many prospects for overcoming the signaling defects and thereby controlling aberrant cell division. The detection of circulating miRNAs associated with breast carcinoma can also be used as biomarkers for early diagnosis. This review article is an attempt to provide updated knowledge on implications of short RNAs and their transport in the breast cancer pathophysiology.

Up-regulation of miR-21 and 146a expression and increased DNA damage frequency in a mouse model of polycystic ovary syndrome (PCOS)

Introduction: Polycystic ovary syndrome (PCOS), a multigenic endocrine disorder, is highly associated with low-grade chronic inflammation, however its etiology remains unclear. In this study, we employed dehydroepiandrosterone (DHEA)-treated mice to reveal the molecular mechanism of inflammation and its correlation with oxidative stress in PCOS patients.

Methods: miR-21 and miR-146a expression levels were measured using quantitative real-time polymerase chain reaction (qRT-PCR). DNA strand breakage frequency was measured using the single cell gel electrophoresis (SCGE) assay (comet assay) and micronucleus test (MN). CRP levels were measured by ELISA method and ESR values were measured by means of Micro-Dispette (Fisher No: 02-675-256) tubes according to the manufacturer’s instructions. Data were analyzed using one-way ANOVA in SPSS 21.0 software.

Results: Our results showed that miR-21 and miR-146a as inflammation markers were upregulated in the sample group in comparison with control group. Erythrocyte sedimentation rate (ESR) and C- reactive protein (CRP) levels were also increased in mouse models of PCOS (p < 0.000). Micronucleated polychromatic erythrocyte (MNPCE) rates per 1000 polychromatic erythrocyte (PCE) significantly increased in DHEA treated mice (6.22 ± 3.28) in comparison with the controls (2.33 ± 2.23, p < 0.000). Moreover, mean arbitrary unit in DHEA treated animals (277 ± 92) was significantly higher than that in controls (184 ± 76, p = 0.005).

Conclusion: To conclude, increased DNA strand breakage frequency and increased expression levels of miR-21 and miR-146a in DHEA administrated animals suggest that low grade chronic inflammation and oxidative stress can act as the main etiologies of PCOS.

Effect of Renal Sympathetic Denervation on Specific MicroRNAs as an Indicator of Reverse Remodeling Processes in Hypertensive Heart Disease

A total of 90 consecutive patients undergoing renal sympathetic denervation (RSD) were included in this study. A significant reduction in office systolic blood pressure (SBP) of 21.1 mm Hg (P<.001) was documented 6 months after RSD. At this time point, circulating concentrations of microRNA (miR)-133a were significantly increased (sevenfold; P<.001) compared with baseline values. Correlation analysis showed a significant relationship between baseline SBP values and SBP reduction (P<.001) as well as between miR-133a baseline levels and the increase in miR-133a expression (P<.001) after the 6-month follow-up. The effect of RSD on miR-133a expression was significantly greater in patients at high risk for hypertensive heart disease. In addition to the effective blood pressure reduction in response to RSD, this study demonstrates an effect of RSD on miR reflecting cardiovascular reverse remodeling processes. Thus, these results provide information on a beneficial effect of RSD on cardiac recovery in patients at high risk for hypertensive heart disease.

Differential regulation of miR-146a/FAS and miR-21/FASLG axes in autoimmune lymphoproliferative syndrome due to FAS mutation (ALPS-FAS)

Most cases of autoimmune lymphoproliferative syndrome (ALPS) have an inherited genetic defect involving apoptosis-related genes of the FAS pathway. MicroRNAs (miRNAs) are a class of small non-coding regulatory RNAs playing a role in the control of gene expression. This is the first report on miRNAs in ALPS patients. We studied a mother and son carrying the same FAS cell surface death receptor (FAS) mutation, but with only the son manifesting the signs and symptoms of ALPS-FAS. The aim was to analyse, by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), the peripheral blood mononuclear cells (PBMC) relative expression of miR-146a and miR-21, including their passenger strands and respective targets (FAS and FASLG). In comparison with healthy matched control individuals, miR-21-3p was over-expressed significantly (P = 0·0313) in the son, with no significant change in the expression of miR-146a, miR-146a-3p and miR-21. In contrast, the mother had a slight under-expression of the miR-146a pair and miR-21-3p (P = 0·0625). Regarding the miRNA targets, FAS was up-regulated markedly for the mother (P = 0·0078), but down-regulated for the son (P = 0·0625), while FASLG did not have any significant alteration. Taken together, our finding clearly suggests a role of the miR-146a/FAS axis in ALPS-FAS variable expressivity in which FAS haploinsufficiency seems to be compensated only in the mother who had the miR-146a pair down-regulated. As only the son had the major clinical manifestations of ALPS-FAS, miR-21-3p should be investigated as playing a critical role in ALPS physiopathology, including the development of lymphoma.

Up-Regulation of miRNA-21 Expression Promotes Migration and Proliferation of Sca-1+ Cardiac Stem Cells in Mice

BACKGROUND This study, by regulating the expression level of microRNA-21 (miRNA-21) in antigen-1+ (Sca-1+) cardiac stem cells (CSCs), examined the role of miRNA-21 in migration, proliferation, and differentiation of Sca-1+ CSCs, and explored the use of miRNA-21 in treatment of heart-related diseases in mice. MATERIAL AND METHODS The CSCs of 20 healthy 2-month-old C57BL/6 mice were collected in our study. Immunomagnetic beads were used to separate and prepare pure Sca-1+ CSCs, which were further examined by flow cytometry. The samples were assigned to 4 groups: the blank group, the miRNA-21 mimic group, the miRNA-21 inhibitor group, and the negative control (NC) group. Quantitative real-time polymerase chain reaction (qRT-PCR), Transwell chamber assay, and the methyl thiazolylte-trazolium (MTT) assay were performed. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to measure the expression levels of GATA-4, MEF2c, TNI, and β-MHC differentiation-related genes. RESULTS Immunomagnetic separation results indicated that Sca-1+ CSCs accounted for more than 87.4% of CSCs. RT-PCR results also showed that the expression level of miRNA-21 of the miRNA-21 mimic group was higher than those of the other groups (all P<0.05). Compared to the NC and the blank group, the migration of Sca-1+ CSCs was more active in the miRNA-21 mimic group and less active in the miRNA-21 inhibitor group (all P<0.05). Moreover, compared to the blank group, the proliferation of Sca-1+ CSCs was enhanced in the miRNA-21 mimic group and inhibited in the miRNA-21 inhibitor group (all P<0.05). The results of RT-PCR indicated that neither miRNA-21 mimics nor miR-21 inhibitors influenced the gene expression levels of GATA-4, MEF2c, TNI, or β-MHC. CONCLUSIONS Our study provides evidence that up-regulation of miRNA-21 can promote migration and proliferation of Sca-1+ CSCs to enhance the capacity of Sca-1+ CSCs to repair damaged myocardium, which may pave the way for therapeutic strategies directed toward restoring miRNA-21 function for heart-related diseases.

microRNA and Allergy

Allergy is a common hypersensitivity disorder of the immune system, which, along with other factors, is also subjected to regulation by microRNAs. The most common allergic diseases are allergic rhinitis, asthma, atopic dermatitis, and food allergy, which all are multifactorial and very heterogeneous conditions, highlighting the need for more individualized treatment techniques. More particular key questions in relation to allergic diseases are how microRNAs influence the differentiation, polarization, plasticity and functions of T helper and other immune cells, as well as the development of immune tolerance. In addition, microRNAs can affect allergic inflammation and tissue remodeling through their functions in epithelial and other tissue cells. Among immune system-related microRNAs, miR-21, miR-146a, and miR-155 are the most intensively studied and have convincingly been demonstrated to regulate immune responses and tissue inflammation in allergic diseases. Further characterization of microRNA functions is important, as similar to other conditions, the modulation of microRNA expression could potentially be used for therapeutic purposes in allergic diseases in the future. In addition, miRNAs could be implemented as biomarkers for endotyping complex allergic conditions.

How Diet Intervention via Modulation of DNA Damage Response through MicroRNAs May Have an Effect on Cancer Prevention and Aging, an in Silico Study

The DNA damage response (DDR) is a molecular mechanism that cells have evolved to sense DNA damage (DD) to promote DNA repair, or to lead to apoptosis, or cellular senescence if the damage is too extensive. Recent evidence indicates that microRNAs (miRs) play a critical role in the regulation of DDR. Dietary bioactive compounds through miRs may affect activity of numerous genes. Among the most studied bioactive compounds modulating expression of miRs are epi-gallocatechin-3-gallate, curcumin, resveratrol and n3-polyunsaturated fatty acids. To compare the impact of these dietary compounds on DD/DDR network modulation, we performed a literature search and an in silico analysis by the DIANA-mirPathv3 software. The in silico analysis allowed us to identify pathways shared by different miRs involved in DD/DDR vis-à-vis the specific compounds. The results demonstrate that certain miRs (e.g., -146, -21) play a central role in the interplay among DD/DDR and the bioactive compounds. Furthermore, some specific pathways, such as "fatty acids biosynthesis/metabolism", "extracellular matrix-receptor interaction" and "signaling regulating the pluripotency of stem cells", appear to be targeted by most miRs affected by the studied compounds. Since DD/DDR and these pathways are strongly related to aging and carcinogenesis, the present in silico results of our study suggest that monitoring the induction of specific miRs may provide the means to assess the antiaging and chemopreventive properties of particular dietary compounds.

Plasma MicroRNA-21 Predicts Postoperative Pulmonary Complications in Patients Undergoing Pneumoresection

Postoperative pulmonary complication (PPC) remains the most common postoperative complication in patients undergoing noncardiac thoracic surgery. We conducted the clinical study to determine the diagnostic role of miRNA-21 in noncardiac thoracic surgery. 368 patients undergoing noncardiac thoracic surgery were recruited. Blood samples were collected before anesthesia and 2 hours after incision during surgery for RT-PCR measurement of miRNA-21. PPC occurrence, extrapulmonary complications, duration of ICU stay, and death within 1 year were evaluated. The overall rate of PPCs following surgery was 10.32%. A high relative miRNA-21 level was an independent risk factor for PPCs within 7 days (OR, 2.69; 95% CI, 1.25-5.66; and P < 0.001). High miRNA-21 was also associated with an increased risk of extrapulmonary complications (OR, 3.62; 95% CI, 2.26-5.81; and P < 0.001), prolonged ICU stay (OR, 6.54; 95% CI, 2.26-18.19; and P < 0.001), increased death within 30 days (OR, 6.17; 95% CI, 2.11-18.08; and P < 0.001), and death within 1 year (OR, 7.30; 95% CI, 2.76-19.28; and P < 0.001). In summary, plasma miRNA-21 may serve as a novel biomarker of PPCs for patients undergoing noncardiac thoracic surgery.

Small-molecule approaches toward the targeting of oncogenic miRNAs: roadmap for the discovery of RNA modulators

miRNAs are a recently discovered class of small noncoding RNAs implicated in the regulation of gene expression. The deregulation of miRNAs levels has been linked to the development of various cancers where oncogenic miRNAs are overexpressed and tumor suppressor miRNAs are underexpressed. Here we report the three main strategies developed in order to discover small-molecule drugs able to selectively interfere with oncogenic miRNAs: the high throughput screening of large libraries of compounds, the focused screening of small libraries of molecules that are known to be able to interact with RNA thus being supposed modulators of miRNAs pathway and the design of small molecules based on the secondary structure of targeted RNA and/or three-dimensional structure of enzymes involved in miRNAs pathway.

Interleukin 34 Upregulation Contributes to the Increment of MicroRNA 21 Expression through STAT3 Activation Associated with Disease Activity in Rheumatoid Arthritis

OBJECTIVE

Interleukin 34 (IL-34) and microRNA 21 (miR-21) were found to be involved in the pathological process of rheumatoid arthritis (RA), but the details were unclear. In this study, we aimed to clarify the relationship between IL-34 and miR-21 in RA.

METHODS

IL-34 concentrations in serum and synovial fluid (SF) of patients with RA were measured by ELISA. Fibroblast-like synovial cells (FLS) were cultured for evaluation of STAT3 activation, miR-21, and Bax/Bcl-2 expression by Western blot and real-time PCR. Correlations were analyzed between clinical features and detectable variables including SF IL-34 levels and miR-21 expression.

RESULTS

SF IL-34 levels were significantly higher in patients with RA who had a high 28-joint Disease Activity Score (DAS28 ≥ 3.2) than in those with a lower DAS28 (DAS28 < 3.2). DAS28 scores and miR-21 expression in FLS had a significant positive correlation with the SF IL-34 levels. In addition, IL-34 stimulation strengthened the activation of p-STAT3, resulting in the increment of miR-21 expression. Inhibiting of miR-21 expression contributed to decreased Bcl-2/Bax ratio, suggesting that miR-21 was involved in the resistance to apoptosis. With the blocking of the colony-stimulating factor-1 receptor (CSF1R), decreased protein expressions including CSF1R, p-STAT3/STAT3, and Bcl-2/Bax were shown, suggesting that CSF1R participated in the biological functions of IL-34 in RA.

CONCLUSION

The IL-34/STAT3/miR-21 pathway is crucial for the survival of synovial fibroblasts in RA, which might be candidate therapeutic targets for RA treatment.

Differential expression of circulating microRNAs in blood and haematoma samples from patients with intracerebral haemorrhage

Objective

To measure the differential expression of microRNAs (miRNAs) in peripheral blood samples from patients with intracerebral haemorrhage (ICH) and to measure the levels of hsa-miR-21-5p in peripheral blood and haematoma samples from patients with ICH.

Methods

This case–control study enrolled individuals with ICH in the putamen treated by craniotomy and age- and sex-matched healthy control subjects. Serum miRNA expression profiles were determined in the patient and control groups using miRNA polymerase chain reaction (PCR) arrays. The ICH-related miRNA hsa-miR-21-5p was selected and its differential expression was assessed in peripheral blood and haematoma specimens from patients with ICH compared with peripheral blood samples controls using real-time PCR.

Results

Seven patients and five control subjects were included in the miRNA expression profile analysis; and 31 patients and 22 control subjects provided samples for the real-time PCR of hsa-miR-21-5p expression. A total of 59 miRNAs were significantly downregulated in patients with ICH. Relative hsa-miR-21-5p levels of 0.43 and 0.31 for peripheral blood and haematoma samples, respectively, were obtained in the patient group compared with the control subjects.

Conclusion

Hsa-miR-21-5p levels were significantly reduced in both peripheral blood and haematoma samples in patients with ICH.

Expression of microRNAs miR21, miR146a, and miR155 in tuberous sclerosis complex cortical tubers and their regulation in human astrocytes and SEGA-derived cell cultures

Tuberous sclerosis complex (TSC) is a genetic disease presenting with multiple neurological symptoms including epilepsy, mental retardation, and autism. Abnormal activation of various inflammatory pathways has been observed in astrocytes in brain lesions associated with TSC. Increasing evidence supports the involvement of microRNAs in the regulation of astrocyte-mediated inflammatory response. To study the role of inflammation-related microRNAs in TSC, we employed real-time PCR and in situ hybridization to characterize the expression of miR21, miR146a, and miR155 in TSC lesions (cortical tubers and subependymal giant cell astrocytomas, SEGAs). We observed an increased expression of miR21, miR146a, and miR155 in TSC tubers compared with control and perituberal brain tissue. Expression was localized in dysmorphic neurons, giant cells, and reactive astrocytes and positively correlated with IL-1β expression. In addition, cultured human astrocytes and SEGA-derived cell cultures were used to study the regulation of the expression of these miRNAs in response to the proinflammatory cytokine IL-1β and to evaluate the effects of overexpression or knockdown of miR21, miR146a, and miR155 on inflammatory signaling. IL-1β stimulation of cultured glial cells strongly induced intracellular miR21, miR146a, and miR155 expression, as well as miR146a extracellular release. IL-1β signaling was differentially modulated by overexpression of miR155 or miR146a, which resulted in pro- or anti-inflammatory effects, respectively. This study provides supportive evidence that inflammation-related microRNAs play a role in TSC. In particular, miR146a and miR155 appear to be key players in the regulation of astrocyte-mediated inflammatory response, with miR146a as most interesting anti-inflammatory therapeutic candidate.

Rapid atrial pacing induces myocardial fibrosis by down-regulating Smad7 via microRNA-21 in rabbit

Tachycardia-induced atrial fibrosis is a hallmark of the structural remodeling of atrial fibrillation (AF). The mechanisms underlying tachycardia-induced atrial fibrosis remain unclear. In our previous study, we found that Smad7-downregulation promoted the development of atrial fibrosis in AF. Fibroblasts are enriched in microRNA-21 (miR-21), which contributes to the development of fibrosis and heart failure in the cardiovascular system. Our study was designed to test the hypothesis that miR-21 reinforces the TGF-β₁/Smad signaling pathway in AF-induced atrial fibrosis by down-regulating Smad7. Rapid atrial pacing (RAP, 1000 ppm) was applied to the left atrium of the rabbit heart to induce atrial fibrillation and fibrosis. qRT-PCR and northern blot analysis revealed that RAP caused a marked increase in the expression of miR-21. Transfection with a miR-21 inhibitor significantly increased the expression of Smad7, while the expression of collagen I/III significantly decreased. These changes were implicated in the AF-induced release of miR-21 and down-regulation of Smad7. Adult rat cardiac fibroblasts treated with TGF-β₁ showed increased miR-21 expression and decreased Smad7 expression. Pretreatment with a TGF-β₁ inhibitor reduced the TGF-β₁-induced up-regulation of miR-21. Pretreatment with pre-miR-21 and a miR-21 inhibitor significantly decreased and increased Smad7 expression, respectively. This result was negatively correlated with the expression of collagen I/III in fibroblasts. Moreover, the results of a luciferase activity assay suggest that Smad7 is a validated miR-21 target in CFs. Our results provide compelling evidence that the miR-21 specific degradation of Smad7 may decrease the inhibitory feedback regulation of TGF-β1/Smad signaling and serves as a new insight of the mechanism of atrial fibrosis in atrial fibrillation.

DDAH1 deficiency promotes intracellular oxidative stress and cell apoptosis via a miR-21-dependent pathway in mouse embryonic fibroblasts

Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, is degraded by dimethylarginine dimethylaminohydrolase 1 (DDAH1). Emerging evidence suggests that plasma ADMA accumulation, DDAH1 activity/expression reduction, and microRNA-21 (miR-21) upregulation are linked to disease pathology, but the mechanisms remain largely unknown. In the present study, we assessed the potential role of the ADMA-DDAH1-miR-21 pathway in the regulation of the cellular redox state and apoptosis using wild-type (WT) and DDAH1-knockout (KO) immortalized mouse embryonic fibroblasts (MEFs). DDAH1 deficiency significantly increased ADMA levels, enhanced cellular oxidative stress, and rendered cells more vulnerable to apoptosis induced by tert-butyl hydroperoxide (tBHP) or A23187. However, treatment with exogenous ADMA (1-80μM) for 24h or for a prolonged period (10μM, 10 passages) in WT MEFs had no marked effect on intracellular reactive oxygen species (ROS) and apoptosis sensitivity. Interestingly, miR-21 expression was significantly increased, by 4 fold, in DDAH1(-/-) MEFs, and the induction of miR-21 by DDAH1 deficiency was dependent on oxidative stress and NF-κB activation. Inhibition of DDAH1 activity by PD 404182 also increased miR-21 expression. Furthermore, inhibition of miR-21 with a lentiviral vector in DDAH1(-/-) MEFs significantly upregulated SOD2 expression and the attenuated oxidative stress and apoptosis induced by tBHP or A23187. Taken together, our results suggest that DDAH1 not only acts as an enzyme degrading ADMA but also controls cellular oxidative stress and apoptosis via a miR-21-dependent pathway.

miR-21 promotes fibrosis in an acute cardiac allograft transplantation model

AIMS

Cardiac transplantation is the only curative therapy for end-stage heart failure. Fibrosis is one of the major causes for impaired function of cardiac allografts. MicroRNAs, a class of small non-coding RNAs, play a critical role in the development of cardiovascular disease, but the role of microRNAs in cardiac allograft failure is not well understood.

METHODS AND RESULTS

To uncover a role of microRNAs during cardiac graft fibrosis, we generated global microRNA profiles in allogeneic (BALB/c in C57BL/6N) and isogeneic (C57BL/6N in C57BL/6N) murine hearts after transplantation. miR-21 together with cardiac fibrosis was increased in cardiac allografts compared with isografts. Likewise, patients with cardiac rejection after heart transplantation showed increased cardiac miR-21 levels. miR-21 was induced upon treatment with IL-6 in a monocyte cell line. Overexpression of miR-21 in this monocyte cell line activated a fibrotic gene programme and promoted monocyte-to-fibrocyte transition together with activation of chemokine (C-C) motif ligand 2 (monocyte chemoattractant protein 1) via the phosphatase and tensin homologue/activator protein 1 regulatory axis. In vivo, both genetic and pharmacological inhibition of miR-21 successfully reduced fibrosis and fibrocyte accumulation in cardiac allografts.

CONCLUSION

Thus, inhibition of miR-21 is a novel strategy to target fibrosis development in cardiac allografts.

Role of microRNAs in allergic asthma: present and future

PURPOSE OF REVIEW

MicroRNAs (miRNAs) modulate gene transcription in response to environmental stressors and other stimuli. A role for miRNAs in inflammation and immunity has been demonstrated and further evidence suggests that miRNAs also play a role in allergic asthma.

RECENT FINDINGS

Studies investigating the differential expression of miRNAs in biological fluids between asthma patients and controls have been published, as have their role in immune cell subsets. Further development of miRNAs in therapy has been addressed. miRNA-146a has been implicated in autoimmunity and allergic inflammation and miRNA-155 in the development of atopy. Targeting of miRNA-1 and miRNA-145 has been used to inhibit lung inflammation in mouse models of asthma. Although these recent findings need to be confirmed, miRNAs may prove to be useful as potential biomarkers of disease. However, their use as therapeutic targets in the lung remains unclear.

SUMMARY

There may be a potential role for using circulating miRNAs as biomarkers of disease status or response to therapy. The use of miRNAs as asthma therapy remains to be determined.

Regulatory roles of microRNA-21 in fibrosis through interaction with diverse pathways (Review)

MicroRNA-21 (miR-21) is a small, non-coding RNA which can regulate gene expression at the post‑transcriptional level. While the fibrogenic process is vital in tissue repair, proliferation and transition of fibrogenic cells combined with an imbalance of secretion and degradation of the extracellular matrix results in excessive tissue remodeling and fibrosis. Recent studies have indicated that miR‑21 is overexpressed during fibrosis and can regulate the fibrogenic process in a variety of organs and tissues via diverse pathways. The present review summarized the significant roles of miR-21 in fibrosis and discussed the underlying key pathways.

Human epididymis protein 4 expression positively correlated with miR-21 and served as a prognostic indicator in ovarian cancer

Ovarian cancer is the most common cause of gynecological malignancy-related mortality. Human epididymis protein 4 (HE4) is a useful biomarker for ovarian cancer when either used alone or in combination with carbohydrate antigen 125 (CA125). What is more, aberrant expression of microRNA-21 (miR-21) has been shown to be involved in oncogenesis, but the relationship between miR-21 and HE4 in ovarian cancer is not clear. Tumor and adjacent tumor tissues from 43 patients with ovarian cancer were examined. Real-time polymerase chain reaction (RT-PCR) was used to detect the expression of HE4 in the carcinoma and adjacent tissues. The associations between HE4 and tumor biological characters were discussed. TaqMan(®) MicroRNA (miRNA) assays were employed to detect the expression of miR-21 in the ovarian carcinoma. In ovarian cancer, the expression of HE4 messenger RNA (mRNA) in cancer tissues was higher than adjacent tumor tissues (P < 0.0001), which was 1.299-fold of adjacent tumor tissues. And, the expression of miR-21 was also up-regulated which was significantly different in the ovarian cancer (the positive rate was 76.74 %). There was a significantly positive correlation between miR-21 and HE4 expression (r = 0.283 and P = 0.066 for HE4 mRNA, r = 0.663 and P < 0.0001 for serum HE4). There was also a significant correlation between miR-21 and tumor grade (r = 0.608, P < 0.0001). Significantly, patients with recent recurrence (less than 6 months, n = 17) have a higher miR-21 expression than those with no recent recurrence. Therefore, HE4 and miR-21 may play an important role in the development and progression of ovarian cancer and they may serve as prognostic indicators in ovarian cancer.

Diagnostic and prognostic accuracy of miR-21 in renal cell carcinoma: a systematic review protocol

INTRODUCTION

Renal cell carcinoma (RCC) is the most common neoplasm in adult kidneys. One of the most important unmet medical needs in RCC is a prognostic biomarker to enable identification of patients at high risk of relapse after nephrectomy. New biomarkers can help improve diagnosis and hence the management of patients with renal cancer. Thus, this systematic review aims to clarify the prognostic and diagnostic accuracy of miR-21 in patients with RCC.

METHODS AND ANALYSIS

We will include observational studies evaluating the diagnostic and prognostic roles of miR-21 in patients with renal cancer. The index test and reference standards should ideally be performed on all patients. We will search PubMed, SCOPUS and ISI Web of Science with no restriction of language. The outcome will be survival measures in adult patients with RCC. Study selection and data extraction will be performed by two independent reviewers. QUADAS-1 will be used to assess study quality. Publication bias and data synthesis will be assessed by funnel plots and Begg's and Egger's tests using Stata software V.11.1.

ETHICS AND DISSEMINATION

No ethical issues are predicted. These findings will be published in a peer-reviewed journal and presented at national and international conferences.

TRAIL REGISTRATION NUMBER

This systematic review protocol is registered in the PROSPERO International Prospective Register of Systematic Reviews, registration number CRD42015025001.

RNA Profiling in Human and Murine Transplanted Hearts: Identification and Validation of Therapeutic Targets for Acute Cardiac and Renal Allograft Rejection

Acute cellular rejection (ACR) is the adverse response of the recipient's immune system against the allogeneic graft. Using human surveillance endomyocardial biopsies (EMBs) manifesting ACR and murine allogeneic grafts, we profiled implicated microRNAs (miRs) and mRNAs. MiR profiling showed that miR-21, -142-3p, -142-5p, -146a, -146b, -155, -222, -223, and -494 increased during ACR in humans and mice, whereas miR-149-5p decreased. mRNA profiling revealed 70 common differentially regulated transcripts, all involved in immune signaling and immune-related diseases. Interestingly, 33 of 70 transcripts function downstream of IL-6 and its transcription factor spleen focus forming virus proviral integration oncogene (SPI1), an established target of miR-155, the most upregulated miR in human EMBs manifesting rejection. In a mouse model of cardiac transplantation, miR-155 absence and pharmacological inhibition attenuated ACR, demonstrating the causal involvement and therapeutic potential of miRs. Finally, we corroborated our miR signature in acute cellular renal allograft rejection, suggesting a nonorgan specific signature of acute rejection. We concluded that miR and mRNA profiling in human and murine ACR revealed the shared significant dysregulation of immune genes. Inflammatory miRs, for example miR-155, and transcripts, in particular those related to the IL-6 pathway, are promising therapeutic targets to prevent acute allograft rejection.

Non-coding RNA in Ovarian Development and Disease

The ovary's primary function is to produce the mature female gamete, the oocyte that, following fertilization, can develop into an embryo, implant within the uterus and ultimately allow the mother's genetic material to be passed along to subsequent generations. In addition to supporting the generation of the oocyte, the ovary and specific ephemeral tissues within it, follicles and corpora lutea, produce steroids that regulate all aspects of the reproductive system, including the hypothalamic/pituitary axis, the reproductive tract (uterus, oviduct, cervix), secondary sex characteristics all of which are also essential for pregnancy and subsequent nurturing of the offspring. To accomplish these critical roles, ovarian development and function are tightly regulated by a number of exogenous (hypothalamic/pituitary) and endogenous (intraovarian) hormones. Within ovarian cells, intricate signalling cascades and transcriptional and post-transcriptional gene regulatory networks respond to these hormonal influences to provide the exquisite control over all of the temporal and spatial events that must be synchronized to allow this organ to successfully complete its function. This book chapter will focus specifically on the role of non-coding RNAs, their identification and described functional roles within the ovary with respect to normal function and their possible involvement in diseases, which involve the ovary.

Genome-wide DNA methylation study identifies genes associated with the cardiovascular biomarker GDF-15

Growth-differentiation factor 15 (GDF-15) is expressed in low to moderate levels in most healthy tissues and increases in response to inflammation. GDF-15 is associated with cardiovascular dysfunction and over-expressed in the myocardium of patients with myocardial infarction (MI). However, little is known about the function of GDF-15 in cardiovascular disease, and the underlying regulatory network of GDF-15 is not known. To investigate a possible association between GDF-15 levels and DNA methylation, we performed a genome-wide DNA methylation study of white blood cells in a population-based study (N = 717). Significant loci where replicated in an independent cohort (N = 963). We also performed a gene ontology (GO) enrichment analysis. We identified and replicated 16 CpG-sites (false discovery rate [FDR] < 0.05), at 11 independent loci including MIR21. MIR21 encodes a microRNA (miR-21) that has previously been shown to be associated with the development of heart disease. Interestingly, GDF15 mRNA contains a binding site for miR-21. Four sites were also differentially methylated in blood from participants previously diagnosed with MI and 14 enriched GO terms (FDR < 0.05, enrichment > 2) were identified, including 'cardiac muscle cell differentiation'. This study shows that GDF-15 levels are associated with differences in DNA methylation in blood cells, and a subset of the loci are also differentially methylated in participants with MI. However, there might be interactions between GDF-15 levels and methylation in other tissues not addressed in this study. These results provide novel links between GDF-15 and cardiovascular disease.

Lipoxin A4 activates alveolar epithelial sodium channel gamma via the microRNA-21/PTEN/AKT pathway in lipopolysaccharide-induced inflammatory lung injury

Lipoxin A4 (LXA4), as an endogenously produced lipid mediator, promotes the resolution of inflammation. Previously, we demonstrated that LXA4 stimulated alveolar fluid clearance through alveolar epithelial sodium channel gamma (ENaC-γ). In this study, we sought to investigate the mechanisms of LXA4 in modulation of ENaC-γ in lipopolysaccharide (LPS)-induced inflammatory lung injury. miR-21 was upregulated during an LPS challenge and downregulated by LXA4 administration in vivo and in vitro. Serum miR-21 concentration was also elevated in acute respiratory distress syndrome patients as compared with healthy volunteers. LPS increased miR-21 expression by activation of activator protein 1 (AP-1). In A549 cells, miR-21 upregulated phosphorylation of AKT activation via inhibition of phosphatase and tensin homolog (PTEN), and therefore reduced the expression of ENaC-γ. In contrast, LXA4 reversed LPS-inhibited ENaC-γ expression through inhibition of AP-1 and activation of PTEN. In addition, an miR-21 inhibitor mimicked the effects of LXA4; overexpression of miR-21 abolished the protective effects of LXA4. Finally, both AKT and ERK inhibitors (LY294002 and UO126) blocked effects of LPS on the depression of ENaC-γ. However, LXA4 only inhibited LPS-induced phosphorylation of AKT. In summary, LXA4 activates ENaC-γ in part via the miR-21/PTEN/AKT signaling pathway.

Paternal long-term exercise programs offspring for low energy expenditure and increased risk for obesity in mice

Obesity has more than doubled in children and tripled in adolescents in the past 30 yr. The association between metabolic disorders in offspring of obese mothers with diabetes has long been known; however, a growing body of research indicates that fathers play a significant role through presently unknown mechanisms. Recent observations have shown that changes in paternal diet may result in transgenerational inheritance of the insulin-resistant phenotype. Although diet-induced epigenetic reprogramming via paternal lineage has recently received much attention in the literature, the effect of paternal physical activity on offspring metabolism has not been adequately addressed. In the current study, we investigated the effects of long-term voluntary wheel-running in C57BL/6J male mice on their offspring's predisposition to insulin resistance. Our observations revealed that fathers subjected to wheel-running for 12 wk produced offspring that were more susceptible to the adverse effects of a high-fat diet, manifested in increased body weight and adiposity, impaired glucose tolerance, and elevated insulin levels. Long-term paternal exercise also altered expression of several metabolic genes, including Ogt, Oga, Pdk4, H19, Glut4, and Ptpn1, in offspring skeletal muscle. Finally, prolonged exercise affected gene methylation patterns and micro-RNA content in the sperm of fathers, providing a potential mechanism for the transgenerational inheritance. These findings suggest that paternal exercise produces offspring with a thrifty phenotype, potentially via miRNA-induced modification of sperm.

Atypical role of sprouty in colorectal cancer: sprouty repression inhibits epithelial-mesenchymal transition

Sprouty (SPRY) appears to act as a tumor suppressor in cancer, whereas we demonstrated that SPRY2 functions as a putative oncogene in colorectal cancer (CRC) (Oncogene, 2010, 29: 5241-5253). We investigated the mechanisms by which SPRY regulates epithelial-mesenchymal transition (EMT) in CRC. SPRY1 and SPRY2 mRNA transcripts were significantly upregulated in human CRC. Suppression of SPRY2 repressed AKT2 and EMT-inducing transcription factors and significantly increased E-cadherin expression. Concurrent downregulation of SPRY1 and SPRY2 also increased E-cadherin and suppressed mesenchymal markers in colon cancer cells. An inverse expression pattern between AKT2 and E-cadherin was established in a human CRC tissue microarray. SPRY2 negatively regulated miR-194-5p that interacts with AKT2 3' untranslated region. Mir-194 mimics increased E-cadherin expression and suppressed cancer cell migration and invasion. By confocal microscopy, we demonstrated redistribution of E-cadherin to plasma membrane in colon cancer cells transfected with miR-194. Spry1(-/-) and Spry2(-/-) double mutant mouse embryonic fibroblasts exhibited decreased cell migration while acquiring several epithelial markers. In CRC, SPRY drive EMT and may serve as a biomarker of poor prognosis.

Endothelial and smooth muscle cell transformation in atherosclerosis

PURPOSE OF REVIEW

Physiologically, endothelial integrity and smooth muscle homeostasis play key roles in the maintenance of vascular structure and functions. Under pathological conditions, endothelial and smooth muscle cells display great plasticity by transdifferentiating into other cell phenotypes. This review aims to update the progress in endothelial and smooth muscle cell transformation and to discuss their underlying mechanisms.

RECENT FINDINGS

At the early stage of atherosclerosis, it was traditionally believed that smooth muscle cells from the media migrate into the intima in which they proliferate to form neointimal lesions. Recently, endothelial cells were shown to undergo transformation to form smooth muscle-like cells that contribute to neointimal formation. Furthermore, not only can medial smooth muscle cells migrate and proliferate, they also have the ability to differentiate into macrophages in the intima in which they form foam cells by uptaking lipids. Finally, the discovery of stem/progenitor cells in the vessel wall that can differentiate into all types of vascular cells has complicated the research field even further.

SUMMARY

Based on the current progress in the research field, it is worthy to explore the contributions of cell transformation to the pathogenesis of atherosclerosis to understand the mechanisms on how they are regulated in order to develop novel therapeutic application targeting these processes to reverse the disease progression.