MicroRNAs in disease and potential therapeutic applications

miR-21 Overexpression Promotes Esophageal Squamous Cell Carcinoma Invasion and Migration by Repressing Tropomyosin 1

The migration and invasion of esophageal squamous cell carcinoma are associated with clinical outcomes, however, the mechanisms remain poorly understood. Here, we found that miR-21 is significantly overexpressed in ESCC, lung cancer, and bladder cancer compared with the adjacent normal tissue. MiR-21 and TPM1 expressions were analyzed by RT-qPCR and WB in 30 ESCC, 10 lung cancer, and 10 bladder cancer clinical specimens, each with matched adjacent normal tissue. Knockdown and overexpression of miR-21 as well as knockdown of TPM1 in ESCC cell lines were performed using synthetic oligonucleotides. TPM1 3′UTR luciferase reporter constructs were used to investigate targeting of TPM1 by miR-21. ESCC migration and invasion were assessed using transwell migration and invasion assays. Inhibition of miR-21 reduced migration and invasion in two ESCC cell lines, and overexpression of miR-21 promoted migration and invasion in vitro. Interestingly, TPM1 exhibited inverse patterns of expression compared with miR-21 in tissues and cell lines. Luciferase reporter assays demonstrated that TPM1 was directly regulated by miR-21. Moreover, the forced overexpression of miR-21 repressed the TPM1 expression, while silencing of miR-21 restored the TPM1 expression in ESCC cell lines. What is more, simultaneous silencing of miR-21 and TPM1 expressions did not alter the migratory and invasive characteristics demonstrating that the effects of miR-21 were mediated through TPM1. In conclusion, the aberrant overexpression of miR-21 is common in cancer and promotes the migration and invasion of ESCC through inhibiting the TPM1 expression. These results suggest that miR-21 may be a novel predictive marker and therapeutic target for treatment of ESCC.

Importance of microRNAs in Skin Oncogenesis and Their Suitability as Agents and Targets for Topical Therapy

Skin cancer is the most common cancer worldwide, with rapidly increasing incidence and consistent mortality. Skin cancer encompasses melanoma and non-melanoma skin cancer, which in turn is mainly divided into cutaneous squamous cell carcinoma and basal cell carcinoma. Small noncoding micro-RNAs (miRNAs) regulate protein expression after transcription and play a role in the development and progression of skin cancer. Deregulated expression of miRNAs in skin cancer is associated with cell proliferation, angiogenesis, metastasis, apoptosis, immune response, and drug resistance. Specific patterns of miRNAs in specific skin cancer types can be used as diagnostic markers. For therapeutic purposes, both miRNA and chemically modified variants thereof as well as miRNA antagonists (antagomiRs) or RNA inhibitors may be applied topically. Due to their specific physicochemical properties, physical or chemical diffusion promoters are used with varying degrees of success. There is no question by now that such preparations have a high potential for the treatment of epithelial skin tumors in particular.

Analysis of G-quadruplexes upstream of herpesvirus miRNAs: evidence of G-quadruplex mediated regulation of KSHV miR-K12-1-9,11 cluster and HCMV miR-US33

BACKGROUND

G-quadruplexes regulate gene expression, recombination, packaging and latency in herpesviruses. Herpesvirus-encoded miRNAs have been linked to important biological functions. The presence and the biological role of G-quadruplexes have not been studied in the regulatory regions of virus miRNA. We hypothesized that herpesvirus-encoded miRNAs are regulated by G-quadruplexes in their promoters.

RESULTS

We analyzed the 1 kb regulatory regions of all herpesvirus-encoded miRNAs for the presence of putative quadruplex-forming sequences (PQS). Over two-third (67%) of the regulatory regions of herpesvirus miRNAs had atleast 1 PQS. The 200 bp region of the promoter proximal to herpesvirus miRNA is particularly enriched for PQS. We chose to study the G-quadruplex motifs in the promoters of miR-K12 cluster in Kaposi's sarcoma-associated Herpesvirus (KSHV miR-K12-1-9,11) and the miR-US33 encoded by Human Cytomegalovirus (HCMV miR-US33). Biophysical characterization indicates that the G-quadruplex motifs in the promoters of the KSHV miR-K12 cluster and the HCMV miR-US33 form stable intramolecular G-quadruplexes in vitro. Mutations disrupting the G-quadruplex motif in the promoter of the KSHV miR-K12 cluster significantly inhibits promoter activity, while those disrupting the motif in the promoter of HCMV miR-US33 significantly enhance the promoter activity as compared to that of the respective wild-type promoter. Similarly, the addition of G-quadruplex binding ligands resulted in the modulation of promoter activity of the wild-type promoters (with intact G-quadruplex) but not the mutant promoters (containing quadruplex-disrupting mutations).

CONCLUSION

Our findings highlight previously unknown mechanisms of regulation of virus-encoded miRNA and also shed light on new roles for G-quadruplexes in herpesvirus biology.

Protective effect and mechanism of microRNA-146a on ankle fracture

The present study investigated the expression and role of microRNA-146a (miR-146a) on ankle fracture, and explored the underlying mechanism. miR-146a levels in the blood of patients with ankle fracture was measured using reverse transcription-quantitative PCR (RT-qPCR). Expression of pro-inflammatory factors in the peripheral blood of ankle fracture patients was also detected using ELISA. Oxidative stress biomarkers including malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) were additionally investigated. The role of miR-146a in ankle fracture was investigated in vitro where MG-63 cells were transfected with miR-146a mimic or miR-146a inhibitor for 2 h, then treated with 1 µg/ml bradykinin for 24 h. An MTT assay was then performed to assess cell viability and pro-inflammatory factors were detected via RT-qPCR and western blot analysis. Finally, activation of the TNF receptor associated factor 6 (TRAF6)/NF-κB pathway was determined via western blotting and RT-qPCR. The results demonstrated that miR-146a was significantly downregulated in the blood of patients with ankle fracture. The protein levels of tumor necrosis factor (TNF-α), interleukin (IL)-1β and IL-6 were significantly upregulated in patients with ankle fracture. In addition, MDA content significantly increased, and SOD and CAT activity significantly decreased in patients with ankle fracture. In vitro experiments demonstrated that miR-146a overexpression significantly enhanced cell viability. miR-146a mimic suppressed BK-induced upregulation of TNF-α, IL-1β, IL-6 and MDA, and increased SOD and CAT activity. Finally, miR-146a mimic inhibited activation of the TRAF6/NF-κB pathway whilst miR-146a inhibitor had the opposite effect. In conclusion, miR-146a may be a potential therapeutic target for the treatment of ankle fracture by inhibiting the inflammatory response and attenuating oxidative stress.

Multi-omics profiling reveals microRNA-mediated insulin signaling networks

Background

MicroRNAs (miRNAs) play a key role in mediating the action of insulin on cell growth and the development of diabetes. However, few studies have been conducted to provide a comprehensive overview of the miRNA-mediated signaling network in response to glucose in pancreatic beta cells. In our study, we established a computational framework integrating multi-omics profiles analyses, including RNA sequencing (RNA-seq) and small RNA sequencing (sRNA-seq) data analysis, inverse expression pattern analysis, public data integration, and miRNA targets prediction to illustrate the miRNA-mediated regulatory network at different glucose concentrations in INS-1 pancreatic beta cells (INS-1), which display important characteristics of the pancreatic beta cells.

Results

We applied our computational framework to the expression profiles of miRNA/mRNA of INS-1, at different glucose concentrations. A total of 1437 differentially expressed genes (DEGs) and 153 differentially expressed miRNAs (DEmiRs) were identified from multi-omics profiles. In particular, 121 DEmiRs putatively regulated a total of 237 DEGs involved in glucose metabolism, fatty acid oxidation, ion channels, exocytosis, homeostasis, and insulin gene regulation. Moreover, Argonaute 2 immunoprecipitation sequencing, qRT-PCR, and luciferase assay identified Crem, Fn1, and Stc1 are direct targets of miR-146b and elucidated that miR-146b acted as a potential regulator and promising target to understand the insulin signaling network.

Conclusions

In this study, the integration of experimentally verified data with system biology framework extracts the miRNA network for exploring potential insulin-associated miRNA and their target genes. The findings offer a potentially significant effect on the understanding of miRNA-mediated insulin signaling network in the development and progression of pancreatic diabetes.

Synergistic Effect of α-Solanine and Cisplatin Induces Apoptosis and Enhances Cell Cycle Arrest in Human Hepatocellular Carcinoma Cells

AIM

The clinical application of cisplatin is limited by severe side effects associated with high applied doses. The synergistic effect of a combination treatment of a low dose of cisplatin with the natural alkaloid α-solanine on human hepatocellular carcinoma cells was evaluated.

METHODS

HepG2 cells were exposed to low doses of α-solanine and cisplatin, either independently or in combination. The efficiency of this treatment modality was evaluated by investigating cell growth inhibition, cell cycle arrest, and apoptosis enhancement.

RESULTS

α-solanine synergistically potentiated the effect of cisplatin on cell growth inhibition and significantly induced apoptosis. This synergistic effect was mediated by inducing cell cycle arrest at the G2/M phase, enhancing DNA fragmentation and increasing apoptosis through the activation of caspase 3/7 and/or elevating the expression of the death receptors DR4 and DR5. The induced apoptosis from this combination treatment was also mediated by reducing the expression of the anti-apoptotic mediators Bcl-2 and survivin, as well as by modulating the miR-21 expression.

CONCLUSION

Our study provides strong evidence that a combination treatment of low doses of α-solanine and cisplatin exerts a synergistic anticancer effect and provides an effective treatment strategy against hepatocellular carcinoma.

Targeting microRNA in hematologic malignancies

PURPOSE OF REVIEW

MiRNAs are critical regulators for gene expression. Numerous studies have revealed how miRNAs contribute to the pathogenesis of hematologic malignancies.

RECENT FINDINGS

The identification of novel miRNA regulatory factors and pathways crucial for miRNA dysregulation has been linked to hematologic malignancies. miRNA expression profiling has shown their potential to predict outcomes and treatment responses. Recently, targeting miRNA biogenesis or pathways has become a promising therapeutic strategy with recent miRNA-therapeutics being developed.

SUMMARY

We provide a comprehensive overview of the role of miRNAs for diagnosis, prognosis, and therapeutic potential in hematologic malignancies.

Downregulation of microRNA-320a inhibits proliferation and induces apoptosis of retinoblastoma cells via targeting TUSC3

MicroRNA (miR)-320a is specific to vertebrates and has been indicated to serve a role in a number of cancer types, such as gastric, colorectal, pancreatic and ovarian cancer. miR-320a has been reported to be expressed at high levels in retinoblastoma tissues; however its role and mechanism of function in retinoblastoma remain to be elucidated. The aim of the present study was to investigate the role of miR-320a in retinoblastoma cells and the underlying mechanisms. The expression of miR-320a in retinoblastoma cell lines Y79 and WERI-Rb-1, and normal human retinal pigment epithelial cell line ARPE-19 was examined via reverse transcription-quantitative PCR (RT-qPCR). TargetScan bioinformatics analysis and dual-luciferase reporter assay were used to predict and reveal the target gene of miR-320a. Target gene expression was detected via RT-qPCR in retinoblastoma cell lines and ARPE-19 cells. Subsequently, gain- or loss-of-function experiments for miR-320a and tumor suppressor candidate 3 (TUSC3) were performed to study the role of miR-320a/TUSC3 in retinoblastoma cells. Cell viability and apoptosis were assessed via MTT and flow cytometry analysis, respectively. Compared with ARPE-19 cells, miR-320a was prominently expressed in retinoblastoma cell lines. TUSC3 was predicted to be a target gene of miR-320a. Compared with ARPE-19 cells, the expression of TUSC3 in retinoblastoma cell lines was reduced. The results of MTT and flow cytometry analysis revealed that overexpression of TUSC3 reduced the viability of retinoblastoma cells and induced apoptosis. Additional analysis indicated that miR-320a inhibitor enhanced the expression of the target gene TUSC3, thereby inhibiting retinoblastoma cell viability and inducing apoptosis. The effects of miR-320a inhibitor on retinoblastoma cells were inhibited by TUSC3-short hairpin RNA. miR-320a regulated the viability and apoptosis of retinoblastoma cells via targeting TUSC3. Therefore, the present study provided a reference for investigating a potential target for the clinical treatment of retinoblastoma.

miRNAs in Health and Disease: A Focus on the Breast Cancer Metastatic Cascade towards the Brain

MicroRNAs (miRNAs) are small non-coding RNAs that mainly act by binding to target genes to regulate their expression. Due to the multitude of genes regulated by miRNAs they have been subject of extensive research in the past few years. This state-of-the-art review summarizes the current knowledge about miRNAs and illustrates their role as powerful regulators of physiological processes. Moreover, it highlights their aberrant expression in disease, including specific cancer types and the differential hosting-metastases preferences that influence several steps of tumorigenesis. Considering the incidence of breast cancer and that the metastatic disease is presently the major cause of death in women, emphasis is put in the role of miRNAs in breast cancer and in the regulation of the different steps of the metastatic cascade. Furthermore, we depict their involvement in the cascade of events underlying breast cancer brain metastasis formation and development. Collectively, this review shall contribute to a better understanding of the uniqueness of the biologic roles of miRNAs in these processes, to the awareness of miRNAs as new and reliable biomarkers and/or of therapeutic targets, which can change the landscape of a poor prognosis and low survival rates condition of advanced breast cancer patients.

Non-Coding RNA: Role in Gestational Diabetes Pathophysiology and Complications

Gestational Diabetes Mellitus (GDM) is defined as glucose intolerance that develops in the second or third trimester of pregnancy. GDM can lead to short-term and long-term complications both in the mother and in the offspring. Diagnosing and treating this condition is therefore of great importance to avoid poor pregnancy outcomes. There is increasing interest in finding new markers with potential diagnostic, prognostic and therapeutic utility in GDM. Non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs and circular RNAs, are critically involved in metabolic processes and their dysregulated expression has been reported in several pathological contexts. The aberrant expression of several circulating or placenta-related ncRNAs has been linked to insulin resistance and β-cell dysfunction, the key pathophysiological features of GDM. Furthermore, significant associations between altered ncRNA profiles and GDM-related complications, such as macrosomia or trophoblast dysfunction, have been observed. Remarkably, the deregulation of ncRNAs, which might be linked to a detrimental intrauterine environment, can lead to changes in the expression of target genes in the offspring, possibly contributing to the development of long-term GDM-related complications, such as metabolic and cardiovascular diseases. In this review, all the recent findings on ncRNAs and GDM are summarized, particularly focusing on the molecular aspects and the pathophysiological implications of this complex relationship.

A simplified system for the effective expression and delivery of functional mature microRNAs in mammalian cells

MicroRNAs (miRNAs) are ~22 nucleotide noncoding RNAs that are involved in virtually all aspects of cellular process as their deregulations are associated with many pathological conditions. Mature miRNAs (mMIRs) are generated through a series of tightly-regulated nuclear and cytoplasmic processing events of the transcribed primary, precursor and mMIRs. Effective manipulations of miRNA expression enable us to gain insights into miRNA functions and to explore potential therapeutic applications. Currently, overexpression of miRNAs is achieved by using chemically-synthesized miRNA mimics, or shRNA-like stem-loop vectors to express primary or precursor miRNAs, which are limited by low transfection efficacy or rate-limiting miRNA processing. To overcome rate-limiting miRNA processing, we developed a novel strategy to express mMIRs which are driven by converging U6/H1 dual promoters. As a proof-of-concept study, we constructed mMIR expression vectors for hsa-miR-223 and hsa-Let-7a-1, and demonstrated that the expressed mMIRs effectively silenced target gene expression, specifically suppressed miRNA reporter activity, and significantly affected cell proliferation, similar to respective primary and precursor miRNAs. Furthermore, these mMIR expression vectors can be easily converted into retroviral and adenoviral vectors. Collectively, our simplified mMIR expression system should be a valuable tool to study miRNA functions and/or to deliver miRNA-based therapeutics.

Altered microRNA profile during fracture healing in rats with diabetes

Background

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that regulate gene expression. There is increasing evidence that some miRNAs are involved in the pathology of diabetes mellitus (DM) and its complications. We hypothesized that the functions of certain miRNAs and the changes in their patterns of expression may contribute to the pathogenesis of impaired fractures due to DM.

Methods

In this study, 108 male Sprague–Dawley rats were divided into DM and control groups. DM rats were created by a single intravenous injection of streptozotocin. Closed transverse femoral shaft fractures were created in both groups. On post-fracture days 5, 7, 11, 14, 21, and 28, miRNA was extracted from the newly generated tissue at the fracture site. Microarray analysis was conducted with miRNA samples from each group on post-fracture days 5 and 11. The microarray findings were validated by real-time polymerase chain reaction (PCR) analysis at each time point.

Results

Microarray analysis revealed that, on days 5 and 11, 368 and 207 miRNAs, respectively, were upregulated in the DM group, compared with the control group. The top four miRNAs on day 5 were miR-339-3p, miR451-5p, miR-532-5p, and miR-551b-3p. The top four miRNAs on day 11 were miR-221-3p, miR376a-3p, miR-379-3p, and miR-379-5p. Among these miRNAs, miR-221-3p, miR-339-3p, miR-376a-3p, miR-379-5p, and miR-451-5p were validated by real-time PCR analysis. Furthermore, PCR analysis revealed that these five miRNAs were differentially expressed with dynamic expression patterns during fracture healing in the DM group, compared with the control group.

Conclusions

Our findings will aid in understanding the pathology of impaired fracture healing in DM and may support the development of molecular therapies using miRNAs for the treatment of impaired fracture healing in patients with DM.

miR-144-mediated Inhibition of ROCK1 Protects against LPS-induced Lung Endothelial Hyperpermeability

Dysfunctional endothelial cell (EC) barrier and increased lung vascular permeability is a cardinal feature of acute lung injury and sepsis that may result in a pathophysiological condition characterized by alveolar flooding, pulmonary edema, and subsequent hypoxemia. In lung ECs, activation of Rho-associated kinase-1 (ROCK1) phosphorylates myosin light chain (MLC)-associated phosphatase at its inhibitory site, which favors phosphorylation of MLC, stress fiber formation, and hyperpermeability during acute lung injury. The role of microRNA-144 (miR-144) has been well investigated in many human diseases, including cardiac ischemia/reperfusion-induced injury, lung cancer, and lung viral infection; however, its role in pulmonary EC barrier regulation remains obscure. Here, we investigated the miR-144-mediated mechanism in the protection of endothelial barrier function in an LPS-induced lung injury model. By using transendothelial electrical resistance and transwell permeability assay to examine in vitro permeability and immunofluorescence microscopy to determine barrier integrity, we showed that ectopic expression of miR-144 effectively blocked lung EC barrier disruption and hyperpermeability in response to proinflammatory agents. Furthermore, using a gain-and-loss-of-function strategy, overexpression of miR-144 significantly decreased ROCK1 expression. Concomitantly, miR-144 inhibits ROCK1-mediated phosphorylation of MLC phosphatase^Thr853 and thus phosphorylation of MLC^Thr18/Ser19 to counteract stress fiber formation in LPS-activated EC. Finally, in LPS-challenged mice, intranasal delivery of miR-144 mimic via liposomes attenuated endotoxemia-induced increases in lung wet/dry ratio, vascular permeability, and inflammation. In conclusion, these data suggest that miR-144-attenuated activation of inflammatory ROCK1/MLC pathway in vascular ECs is a promising therapeutic strategy to counter inflammatory lung injury.

Cholesterol metabolism regulation mediated by SREBP-2, LXRα and miR-33a in rainbow trout (Oncorhynchus mykiss) both in vivo and in vitro

Cholesterol metabolism is greatly affected in fish fed plant-based diet. The regulation of cholesterol metabolism is mediated by both transcriptional factors such as sterol regulatory element-binding proteins (SREBPs) and liver X receptors (LXRs), and posttranscriptional factors including miRNAs. In mammals, SREBP-2 and LXRα are involved in the transcriptional regulation of cholesterol synthesis and elimination, respectively. In mammals, miR-33a is reported to directly target genes involved in cholesterol catabolism. The present study aims to investigate the regulation of cholesterol metabolism by SREBP-2 and LXRα and miR-33a in rainbow trout using in vivo and in vitro approaches. In vivo, juvenile rainbow trout of ~72 g initial body weight were fed a total plant-based diet (V) or a marine diet (M) containing fishmeal and fish oil. In vitro, primary cell culture hepatocytes were stimulated by graded concentrations of 25-hydroxycholesterol (25-HC). The hepatic expression of cholesterol synthetic genes, srebp-2 and miR-33a as well as miR-33a level in plasma were increased in fish fed the plant-based diet, reversely, their expression in hepatocytes were inhibited with the increasing 25-HC in vitro. However, lxrα was not affected neither in vivo nor in vitro. Our results suggest that SREBP-2 and miR-33a synergistically enhance the expression of cholesterol synthetic genes but do not support the involvement of LXRα in the regulation of cholesterol elimination. As plasma level of miR-33a appears as potential indicator of cholesterol synthetic capacities, this study also highlights circulating miRNAs as promising noninvasive biomarker in aquaculture.

sRNA/L1 retrotransposition: using siRNAs and miRNAs to expand the applications of the cell culture-based LINE-1 retrotransposition assay

The cell culture-based retrotransposition reporter assay has been (and is) an essential tool for the study of vertebrate Long INterspersed Elements (LINEs). Developed more than 20 years ago, this assay has been instrumental in characterizing the role of LINE-encoded proteins in retrotransposition, understanding how ribonucleoprotein particles are formed, how host factors regulate LINE mobilization, etc. Moreover, variations of the conventional assay have been developed to investigate the biology of other currently active human retrotransposons, such as Alu and SVA. Here, we describe a protocol that allows combination of the conventional cell culture-based LINE-1 retrotransposition reporter assay with short interfering RNAs (siRNAs) and microRNA (miRNAs) mimics or inhibitors, which has allowed us to uncover specific miRNAs and host factors that regulate retrotransposition. The protocol described here is highly reproducible, quantitative, robust and flexible, and allows the study of several small RNA classes and various retrotransposons. To illustrate its utility, here we show that siRNAs to Fanconi anaemia proteins (FANC-A and FANC-C) and an inhibitor of miRNA-20 upregulate and downregulate human L1 retrotransposition, respectively. This article is part of a discussion meeting issue 'Crossroads between transposons and gene regulation'.

Long Noncoding RNA SNHG7, a Molecular Sponge for microRNA-485, Promotes the Aggressive Behavior of Cervical Cancer by Regulating PAK4

Purpose

A long noncoding RNA called small nucleolar RNA host gene 7 (SNHG7) is known to be a key regulator of biological processes in multiple human cancer types. In this study, our aims were to determine the expression status of SNHG7 in cervical cancer, to figure out the detailed roles of SNHG7 in cervical cancer cells, and to identify the mechanism underlying the activity of SNHG7 in cervical cancer.

Methods

Reverse-transcription quantitative PCR was performed to measure SNHG7 expression in cervical cancer. A Cell Counting Kit-8 assay, flow-cytometric analysis, cell migration and invasion assays, and a tumor xenograft experiment were conducted to respectively determine the effects of SNHG7 on cervical cancer cell proliferation, apoptosis, migration, and invasion in vitro and tumor growth in vivo.

Results

SNHG7 was found to be markedly upregulated in cervical cancer tissues and cell lines. Higher SNHG7 expression significantly correlated with FIGO stage, lymph node metastasis, the depth of cervical invasion, and shorter overall survival in patients with cervical cancer. Functional experiments indicated that a SNHG7 knockdown attenuated proliferation, migration, and invasiveness and promoted apoptosis of cervical cancer cells in vitro. The SNHG7 knockdown also slowed tumor growth in vivo. Further investigation showed that SNHG7 acts as a competing endogenous RNA for microRNA-485 (miR-485) in cervical cancer cells, and the inhibitory actions of the SNHG7 knockdown on the malignant phenotype were reversed by miR-485 inhibition. P21-activated kinase 4 (PAK4) was identified as a direct target gene of miR-485 in cervical cancer, and PAK4 expression was promoted by SNHG7.

Conclusion

SNHG7 functions as an oncogenic RNA in cervical cancer, competitively binds to miR-485, and thereby upregulates PAK4. This SNHG7–miR-485–PAK4 regulatory network may provide insights into the pathogenesis of cervical cancer, and can help in the identification of novel diagnostic and therapeutic approaches for cervical cancer.

miR-137 alleviates focal cerebral ischemic injury in rats by regulating JAK1/STAT1 signaling pathway

The repairing effect and potential mechanism of miR-137 on cerebral ischemic injury in rats was investigated. The volume of cerebral infarction and calculated brain water content was detected by triphenyltetrazolium chloride staining. The expression of inflammatory factors was detected by enzyme-linked immunosorbent assay. The pathological damage of brain tissue was analyzed by hematoxylin and eosin and Nissl staining. The apoptosis in ischemic brain tissue was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling. The levels of STAT1 and JAK1 proteins were analyzed by Western blot. The expression of miR-137 in primary hippocampal neurons was detected by reverse transcription polymerase chain reaction. miR-137 overexpression significantly improved brain damage in rats. miR-137 overexpression can reduce the expression of TNF-α, IL-1β, and IL-6. miR-137 overexpression can reduce the degree of brain tissue damage and inhibit the expression of JAK1 and STAT1 proteins. miR-137 overexpression can reduce oxygen-glucose deprivation (OGD)/R-induced cell damage, improve cell proliferation, and reduce apoptotic rate. JAK1 and STAT1 protein expression was inhibited in hippocampal neurons after OGD/R treatment after transfection with miR-137 mimic. After the addition of the Filgotinib inhibitor, the levels of JAK1 and STAT1 proteins were significantly reduced. The results suggested that miR-137 overexpression can effectively improve ischemic injury after focal cerebral ischemia and protect against by inhibiting JAK1/STAT1 pathway.

miR‑217 and miR‑543 downregulation mitigates inflammatory response and myocardial injury in children with viral myocarditis by regulating the SIRT1/AMPK/NF‑κB signaling pathway

The aim of the present study was to investigate the expression levels and roles of microRNA (miR)‑217 and miR‑543 in viral myocarditis, and to examine their underlying mechanisms. Coxsackievirus B3 (CVB3) was used to establish in vivo and in vitro models of viral myocarditis. The levels of miR‑217 and miR‑543 were detected using reverse transcription‑quantitative PCR. The association between miR‑217 and miR‑543 and sirtuin‑1 (SIRT1) was predicted and confirmed by TargetScan and dual‑luciferase reporter assay. Cell viability was detected using Cell Counting Kit‑8 assay, and cell apoptosis was measured by analyzing the expression levels of Bcl‑2 and Bax, and by flow cytometry. In addition, the synthesis of various pro‑inflammatory factors was determined by ELISA. In addition, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were measured in cardiomyocytes following transfection and CVB infection. miR‑217 and miR‑543 were found to be highly expressed in the peripheral blood of pediatric patients with viral myocarditis, in the peripheral blood and myocardial tissues of viral myocarditis mice and in CVB3‑infected cardiomyocytes. SIRT1 was found to be a target of both miR‑217 and miR‑543, and SIRT1 expression level was downregulated in viral myocarditis. Further analysis indicated that the reduced cell viability, increased cell apoptosis, enhanced synthesis of inflammatory factors, increased MDA content and decreased SOD activity associated with myocarditis were significantly reversed after inhibition of miR‑217 or miR‑543. Importantly, the present results showed that all the effects of miR‑217 and miR‑543 inhibition on cardiomyocytes were significantly suppressed following SIRT1 knockdown. Collectively, the present data indicated that miR‑217 and miR‑543 were significantly upregulated in viral myocarditis, and downregulation of miR‑217 and miR‑543 attenuated CVB3 infection‑induced cardiomyocyte injury by targeting SIRT1. miR‑217 and miR‑543 may be potential therapeutic targets for developing novel viral myocarditis treatments in the future.

Identification of Diagnostic and Prognostic microRNAs for Recurrent Vitreous Hemorrhage in Patients with Proliferative Diabetic Retinopathy

MicroRNAs (miRNAs) can provide insight into the pathophysiological states of ocular tissues such as proliferative diabetic retinopathy (PDR). In this study, differences in miRNA expression in vitreous from PDR patients with and without incidence of recurrent vitreous hemorrhage (RVH) after the initial pars-plana vitrectomy (PPV) were analyzed, with the aim of identifying biomarkers for RVH. Fifty-four consented vitreous samples were analyzed from patients undergoing PPV for PDR, of which eighteen samples underwent a second surgery due to RVH. Ten of the sixty-six expressed miRNAs (miRNAs-19a, -20a, -22, -27a, -29a, -93, -126, -128, -130a, and -150) displayed divergences between the PDR vitreous groups and to the control. A significant increase in the miRNA-19a and -27a expression was determined in PDR patients undergoing PPV as compared to the controls. miRNA-20a and -93 were significantly upregulated in primary PPV vitreous samples of patients afflicted with RVH. Moreover, this observed upregulation was not significant between the non-RVH and control group, thus emphasizing the association with RVH incidence. miRNA-19a and -27a were detected as putative vitreous biomarkers for PDR, and elevated levels of miRNA-20a and -93 in vitreous with RVH suggest their biomarker potential for major PDR complications such as recurrent hemorrhage incidence.

Assessment of the Diagnostic Potential of miR-29a-3p and miR-92a-3p as Circulatory Biomarkers in Acute Myeloid Leukemia

Background:

Acute myeloid leukemia (AML) is a set of Myeloproliferative neoplasms that are identified by excessive growth of myeloid blasts and production of abnormal blood cells. AML is the most common type of acute leukemia that occurs in adults. In addition, AML progresses rapidly and is considered a fatal disease. Thus, there is an urgent need to find new targets for molecularly designed therapies. In This study, we evaluated the circulatory levels of microRNA-29a-3p (miR-29a-3p) and miR-92a-3p beside exploring the expression pattern of their target gene myeloid cell leukemia sequence1 (MCL1) to investigate the role of these molecules in AML pathophysiology and to assess their ability to diagnose AML patients.

Methods:

40 adult AML patients along with 20 healthy subjects were enrolled in this study. Plasma were separated from venous blood samples, collected on EDTA, of all individuals were used to assess circulating miRNAs’ levels. In the meantime, total RNA was extracted from isolated leukocytes and was used to quantify target mRNA transcript levels.

Results:

Our data revealed that the circulating levels of miR-29a-3p and miR-92a-3p exhibited significant reduction in 90% and 100% of AML patients, respectively, when compared to the control group (p<0.001). On the other hand, the transcript level of the target gene of these miRNAs, MCL1, showed a sharp increase in 77.5% (p<0.001) of AML patients, along with a negative correlation with its regulatory miRNAs, miR-29a-3p and miR-92a-3p.

Conclusion:

Our data validates the negative regulatory role of miR-29a-3p and miR-92a-3p to the expression levels of MCL1 in peripheral blood and indicates that these miRNAs can be used as non-invasive diagnostic markers. Furthermore, our study highlights the therapeutic potential of miR-29a-3p and miR-92a-3p to target and downregulate a very important gene (MCL1), which is highly implicated in the pathogenesis of AML.

miR-22-3p is involved in gluconeogenic pathway modulated by 3,5-diiodo-L-thyronine (T2)

The 3,5-diiodo-L-thyronine (T2) has emerged as an active iodothyronine and its beneficial effects on glucose metabolism including glucose tolerance and insulin resistance is well established. However, little is known about its molecular mechanisms. Given the emerging importance of microRNAs in various metabolic diseases, in this study a possible link between the effects of T2 on glucose metabolism and miRNA expression was investigated by using an in vivo model in which T2 was administered in rats receiving a high fat diet, a condition known to impair glucose homeostasis. The results showed that T2-treated rats had a better tolerance to glucose load and a better performance at the insulin tolerance test in comparison to high fat diet animals. Interestingly, in the serum of the animals treated with T2 there was a general decrease of miRNAs with miR-22a-3p, miR-34c-5p and miR-33a-3p significantly downregulated. Furthermore, miR-22a-3p had the largest variation pointing toward its preeminent role in T2 metabolic effect. In fact, in liver there was an up-regulation of its target (Transcription Factor 7) Tcf7, which had an important impact on gluconeogenesis. This study provide, for the first time, evidences that miRNAs are involved in the effects exerted by T2 on glucose homeostasis.

Elevated miR-195-5p expression in deep vein thrombosis and mechanism of action in the regulation of vascular endothelial cell physiology

Deep vein thrombosis (DVT) is one of the most common cardiovascular diseases. The apoptosis of vascular endothelial cells is the most important cause of venous thrombosis. MicroRNAs (miRNAs) play important roles in the regulation of cell apoptosis. miRNA (miR)-195 is upregulated in the blood of patients with DVT, and it was predicted that Bcl-2 is a potential target of miR-195-5p. Therefore, it was hypothesized that miR-195-5p may play an important role in the development of DVT by targeting Bcl-2. The present study aimed to investigate the expression of miR-195-5p in DVT patients, and to explore whether miR-195-5p is involved in the development of DVT by regulating the apoptosis of vascular endothelial cells. The level of miR-195-5p was detected using reverse transcription-quantitative PCR. Dual luciferase reporter assays were used to determine the relationship between Bcl-2 and miR-195-5p. Cell viability was detected using MTT assays, and cell apoptosis was analyzed by flow cytometry. Protein levels of Bcl-2 and Bax were measured by western blotting. The results indicated that miR-195-5p was significantly upregulated in the blood of DVT patients. It was also revealed that Bcl-2 was a direct target of miR-195-5p, and that Bcl-2 was downregulated in the blood of patients with DVT. miR-195-5p downregulation promoted cell viability and inhibited the apoptosis of human umbilical vein endothelial cells (HUVECs). miR-195-5p upregulation inhibited cell viability and increased the apoptosis of HUVECs. All of the observed effects of miR-195-5p upregulation on HUVECs were reversed by raised Bcl-2 expression. In conclusion, miR-195-5p was significantly upregulated in patients with DVT, and it may be involved in the development of DVT by regulating the apoptosis of vascular endothelial cells. Therefore, miR-195-5p may be a potential target for predicting and treating DVT.

Evaluation of The Expression Levels of Three Long Non-Coding RNAs in Multiple Sclerosis

Objective

Multiple sclerosis (MS) is a chronic disorder involving both inflammatory and neurodegenerative responses. Long non-coding RNAs (lncRNAs) have been had an emerging role as the biomarkers of different disorders, including autoimmune diseases. Previous studies have shown that NR_003531.3 (MEG3a), AC000061.1_201, and AC007182.6 play a role in the pathogenesis of human autoimmune diseases. However, the potential significance of these lncRNAs, as the diagnostic biomarkers of MS, has not been studied yet. We aimed to quantitatively evaluate the expression levels of NR_003531.3, AC000061.1_201, and AC007182.6 in peripheral blood samples of MS patients in comparison with healthy controls.

Materials and Methods

In this case-control study, the blood samples from 20 MS patients and 10 healthy controls were collected. Total RNA was extracted, and the expression levels of three selected lncRNAs were quantitatively measured using the quantitative real time-polymerase chain reaction (qRT-PCR) method.

Results

We detected a significant down-regulation in the expression of NR_003531.3 in MS patients, while no marked changes were observed in the expression of AC000061.1_201 and AC007182.6 in patients compared with controls. Based on the receiver operating characteristic (ROC) curve analysis, NR_003531.3 could discriminate MS patients from healthy subjects effectively. Regarding the prognosis of MS patients, NR_003531.3 is significantly and inversely correlated with the expanded disability status scale (EDSS).

Conclusion

The potential role of NR_003531.3 lncRNA as a diagnostic biomarker to distinguish MS patients is proposed. Prognostically, NR_003531.3 correlates with lower disability rates in MS patients.

MicroRNA-146a protects against intracerebral hemorrhage by inhibiting inflammation and oxidative stress

The present study aimed to investigate the role of microRNA-146a (miR-146a) in intracerebral hemorrhage (ICH), and to further assess its underlying mechanism. An ICH rat model was established in the current study and 1 h following ICH induction, rats were treated with or without an miR-146a mimic. A total of 3 days following ICH induction, rat neurological score, brain water content and neuronal apoptosis were measured via flow cytometry. Levels of pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1β were detected via ELISA and certain biomarkers of oxidative stress, including malondialdehyde, superoxide dismutase and glutathione peroxidase, were also determined in current study. The expression of genes and proteins were detected in current study via reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. MicroRNA.org software and a dual luciferase reporter assay were used to confirm the association between miR-146a and TRAF6. The results of the current study revealed that miR-146a was significantly downregulated in ICH rats, and its overexpression reduced neurological damage and brain edema, as evidenced by decreased neurological scores and brain water content. Results from further analyses demonstrated that the overexpression of miR-146a inhibited neuronal apoptosis, reduced pro-inflammatory cytokine production and prevented oxidative stress in ICH rats. In addition, it was revealed that the upregulation of miR-146a repressed the TRAF6/NF-κB pathway in the brain tissue of ICH rats. TRAF6 was also determined to be a target of miR-146a. In conclusion, these data indicated that miR-146a protects against ICH by inhibiting inflammation and oxidative stress.

Protocols for the Analysis of microRNA Expression, Biogenesis, and Function in Immune Cells

MicroRNAs (miRNAs) are short (19- to 25-nucleotide) noncoding RNA molecules that target mRNAs to repress gene expression and that play important roles in regulating many fundamental biological functions including cell differentiation, development, growth, and metabolism. They are well conserved in eukaryotic cells and are considered essential ancient elements of gene regulation. miRNA genes are transcribed by RNA polymerase II to generate primary miRNAs (pri-miRNAs), which are cleaved by microprocessor complex in the nucleus to generate stem-loop structures known as pre-miRNAs. Pre-miRNAs are translocated to the cytoplasm and cleaved by Dicer to form the mature miRNAs, which mediate mRNA degradation through their loading to the RNA-induced silencing complex (RISC) and binding to complementary sequences within target mRNAs to repress their translation by mRNA degradation and/or translation inhibition. Because ∼1900 miRNA genes are reported in the human genome, many associated with disease, appropriate methods to study miRNA expression and regulation under physiological and pathological conditions have become increasingly important to the study of many aspects of human biology, including immune regulation. As with small interfering RNA (siRNA), the mechanism of miRNA-mediated targeting has been used to develop miRNA-based therapeutics. For a complete and systematic analysis, it is critical to utilize a variety of different tools to analyze the expression of pri-mRNAs, pre-miRNAs, and mature miRNAs and characterize their targets both in vitro and in vivo. Such studies will facilitate future novel drug design and development. This unit provides six basic protocols for miRNA analysis, covering next-generation sequencing, quantitative real-time PCR (qRT-PCR), and digoxigenin-based expression analysis of pri-mRNAs, pre-miRNAs, and mature miRNAs; mapping of pri-miRNA and their cleavage sites by rapid amplification of cDNA ends (RACE); electrophoretic mobility shift assays (EMSAs) or biotin-based nonradioactive detection of miRNA-protein complexes (miRNPs); and functional analysis of miRNAs using miRNA mimics and inhibitors. © 2019 by John Wiley & Sons, Inc.

Nonconserved miR-608 suppresses prostate cancer progression through RAC2/PAK4/LIMK1 and BCL2L1/caspase-3 pathways by targeting the 3'-UTRs of RAC2/BCL2L1 and the coding region of PAK4

The aim of this study is to investigate the functions and mechanisms of miR-608 in prostate cancer (PCa). CISH and qRT-PCR analysis demonstrated that miR-608 was low expressed in PCa tissues and cells, which was partly attributed to the methylation of CpG island adjacent to the transcription start site (TSS) of miR-608 gene. Intracellular miR-608 overexpression inhibited in vivo PCa tumor growth, and suppressed PCa cell proliferation, G2/M transition, and migration in vitro, which was independent of EMT-associated mechanisms. Then RAC2, a GTPase previously deemed hematopoiesis-specific but now discovered to exist and play important roles in PCa, was verified by western blot and dual-luciferase reporter assays to mediate the effects of miR-608 through RAC2/PAK4/LIMK1/cofilin pathway. MiR-608 also promoted the apoptosis of PCa cells through BCL2L1/caspase-3 pathway by targeting the 3'-UTR of BCL2L1. Moreover, PAK4, the downstream effector of RAC2, was found to be targeted by miR-608 at the mRNA coding sequence (CDS) instead of the canonical 3'-UTR. Knocking down RAC2, PAK4, or BCL2L1 with siRNAs reproduced the antiproliferative, mitosis-obstructive, antimigratory and proapoptotic effects of miR-608 in PCa cells, which could be attenuated by downregulating miR-608. In conclusion, miR-608 suppresses PCa progression, and its activation provides a new therapeutic option for PCa.

MicroRNA‑217 is involved in the progression of atherosclerosis through regulating inflammatory responses by targeting sirtuin 1

Atherosclerosis is a chronic inflammatory disease, and it is a global clinical problem. The development of new and effective therapeutic targets for atherosclerosis is necessary. A number of microRNAs (miRNAs) have been demonstrated to serve a crucial role in atherosclerosis. However, the role of miRNA (miR)-217 in atherosclerosis remains unclear. Therefore, the aim of the present study was to investigate the role and mechanism of miR-217 in atherosclerosis. The level of miR-217 was detected in the blood of patients with atherosclerosis using reverse transcription-quantitative PCR. THP-1 acute monocytic leukemia cells were treated with oxidized low-density lipoprotein (ox-LDL) to develop an atherosclerotic cell model of macrophages. The relationship between miR-217 and sirtuin 1 (SIRT1) was determined by TargetScan and dual luciferase reporter assay. Cell apoptosis was measured by flow cytometry. Production of pro-inflammatory factors and triglyceride (TG) and total cholesterol (TC) levels were also determined. The results demonstrated that miR-217 was significantly upregulated in atherosclerosis. SIRT1 was demonstrated to be a direct target of miR-217 and was downregulated in atherosclerosis. Downregulation of miR-217 significantly inhibited ox-LDL-induced TG and TC level increase, cell apoptosis and the upregulation of the pro-inflammatory factors tumor necrosis factor α, interleukin (IL)-6 and IL-1β. Additionally, the SIRT1/AMP-activated protein kinase α/NF-κB pathway was at least partially involved in modulating the effects of miR-217 inhibition on THP-1 cells treated with ox-LDL. In addition, the effects of miR-217 downregulation on ox-LDL-treated THP-1 cells were eliminated by SIRT1 silencing. In conclusion, the results of the present study indicated that miR-217 downregulation may relieve atherosclerosis through the inhibition of macrophage apoptosis and inflammatory response by targeting SIRT1.

MicroRNA-135a-5p is involved in osteoporosis progression through regulation of osteogenic differentiation by targeting RUNX2

A number of microRNAs (miRs) have been revealed to be involved in the development of osteoporosis, including postmenopausal osteoporosis. The aim of the present study was to investigate miR-135a-5p expression and the cellular function of miR-135a-5p and its underlying mechanism in postmenopausal osteoporosis. miR-135a-5p expression levels in the femoral neck trabecular bone tissue fragments from postmenopausal women with or without osteoporosis were detected by reverse transcription-quantitative polymerase chain reaction and western blot analysis. The role of miR-135a-5p during osteogenic differentiation was examined by performing gain- and loss-of-function experiments using miR-135a-5p mimic or inhibitor. TargetScan bioinformatics analysis was sued to predict targets of miR-135a-5p, which were confirmed using luciferase reporter assays. miR-135a-5p expression was significantly upregulated in femoral neck trabecular bone tissue fragments from postmenopausal women with osteoporosis compared with postmenopausal women without osteoporosis. In addition, miR-135a-5p expression levels significantly decreased during osteogenic differentiation in the C2C12 cell model. miR-135a-5p overexpression decreased the osteogenic potential of C2C12 cells, as miR-135a-5p overexpression significantly reduced the expression levels of several key osteoblast markers, whilst miR-135a-5p knockdown had the opposite effect. Furthermore, the current study demonstrated that RUNX2 was a direct target of miR-135a-5p. Rescue experiments indicated that RUNX2 overexpression significantly reversed the effect of miR-135a-5p mimic on the osteogenic potential of C2C12 cells, indicating that miR-135a-5p mediates osteogenic differentiation via direct targeting of RUNX2. Taken together, these results suggest that miR-135a-5p may serve a role in osteoporosis progression by regulating osteogenic differentiation via RUNX2.

MicroRNA-98-5p prevents bone regeneration by targeting high mobility group AT-Hook 2

MicroRNAs (mRNAs or miRs) serve an important role in the regulation of gene expression. In the present study, the role of miR-98-5p in bone regeneration was determined. Three osteoblast cell models were established, including primary human stem cells (BMMSC), mouse BMMSC's and MC3T3-E1 cells. miR-98-5p expression was determined using reverse transcription-quantitative (RT-q)PCR. Osteoblast markers, including alkaline phosphatase, runt related transcription factor 2 and transcription factor Sp7, were determined using RT-qPCR and western blot analysis, respectively. Alkaline phosphatase activity was determined in the present study and cell proliferation and apoptosis assays were performed. Furthermore, an association between miR-98-5p and high mobility group AT-Hook 2 (HMGA2) was revealed. This association was determined using TargetScan and a dual luciferase reporter assay. The current study demonstrated that miR-98-5p was downregulated during osteogenic differentiation and further demonstrated that HMGA2 may be a direct target of miR-98-5p. The results also demonstrated that miR-98-5p upregulation significantly inhibited the osteogenic differentiation of MC3T3-E1 cells, an effect that was reversed by an increased HMGA2 expression. Additionally, the results revealed that miR-98-5p upregulation inhibited MC3T3-E1 cell viability and induced cell apoptosis and these effects were eliminated by HMGA2 overexpression. In conclusion, miR-98-5p may prevent bone regeneration through inhibiting osteogenic differentiation and osteoblast growth by targeting HMGA2.

Association of miR-146a, miR-149 and miR-196a2 polymorphisms with neuroblastoma risk in Eastern Chinese population: a three-center case-control study

Neuroblastoma is one of the most common malignancy in childhood, which originates from the developing sympathetic nervous system. Single nucleotide polymorphisms (SNPs) in primary miRNA (pri-miRNA) have shown to associate with cancer susceptibility, including neuroblastoma. Three precursor miRNA (pre-miRNA) SNPs (pre-miR-146a rs2910164, pre-miR-149 rs2292832 and pre-miR-196a2 rs11614913) were found to contribute to pathogenesis of various diseases. Here, to evaluate the association among these three pre-miRNA SNPs and neuroblastoma susceptibility in Eastern Chinese children, we carried out a three-center case-control study involving 312 neuroblastoma cases and 762 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association of these three polymorphisms with neuroblastoma risk. However, no significant association was observed among these three SNPs and neuroblastoma susceptibility, in either overall or subgroups analysis by tumor sites, gender and age. Further larger studies consisting of diverse ethnic populations are required to clarify the associations among these three pre-miRNAs polymorphisms and neuroblastoma risk.

MicroRNA‑217 inhibition relieves cerebral ischemia/reperfusion injury by targeting SIRT1

MicroRNAs (miRs) have been proposed to be involved in the pathological processes of cerebral ischemia/reperfusion (CIR) injury. The present study aimed to investigate the potential role and molecular mechanisms of miR-217 in the regulation of neuronal survival in CIR injury. To perform the investigation, an in vitro cellular model of CIR injury was established by treating neurons with oxygen-glucose deprivation and reoxygenation (OGD/R). miR-217 levels in neurons were detected using reverse transcription-quantitative PCR. The association between miR-217 and sirtuin 1 (SIRT1) was identified using TargetScan and validated in a dual-luciferase reporter assay. Cell viability and apoptosis were measured using a Cell Counting Kit-8 assay and flow cytometry, respectively. The release of lactate dehydrogenase, and the production of proinflammatory factors and oxidative stress biomarkers were analyzed by ELISAs and using specific assay kits. It was revealed that miR-217 was significantly upregulated in OGD/R-treated neurons. SIRT1 was a direct target of miR-217, and was downregulated in neurons following OGD/R treatment. Downregulation of miR-217 significantly ameliorated OGD/R-induced neuronal injury, inflammatory responses and oxidative stress. The effects of miR-217 inhibitor on OGD/R treated neurons were attenuated by SIRT1 knockdown. Additionally, western blotting revealed that the SIRT1/AMP-activated protein kinase-α/NF-κB pathway was partially involved in the regulation of OGD/R-induced neuronal injury by miR-217. In conclusion, the data of the present study indicated that the downregulation of miR-217 protected neurons against OGD/R-induced injury by targeting SIRT1.

MicroRNA‑486‑5p inhibits the growth of human hypertrophic scar fibroblasts by regulating Smad2 expression

The aim of the current study was to investigate the expression and role of microRNA-486-5p (miR-486-5p) in hypertrophic scar (HS) formation, and to examine the associated mechanisms. First, miR-486-5p expression was detected in HS tissues and human hypertrophic scar fibroblasts (hHSFs) by reverse transcription-quantitative polymerase chain reaction. Target genes of miR-486-5p were predicted using TargetScan and verified by dual-luciferase reporter assays. To investigate the role of miR-486-5p in HS formation, miR-486-5p was overexpressed in hHSFs through transfection with miR-486-5p mimics. MTT, cell apoptosis and cell cycle assays were preformed to investigate the proliferation, cell apoptosis and cell cycle distribution of hHSFs, respectively. Additionally, protein expression was measured by western blot analysis. The results demonstrated that miR-486-5p expression was significantly decreased in HS tissues and cells. Mothers against decapentaplegic homolog (Smad)2 was a target gene of miR-486-5p, and it was negatively regulated by miR-486-5p. It was also found that Smad2 expression was significantly increased in HS tissues and cells. Further analysis indicated that miR-486-5p mimic transfection inhibited the proliferation, induced cell apoptosis and increased G1/S phase arrest in hHSFs. Furthermore, the expression of cyclin-dependent kinase (CDK)2, CDK4 and apoptosis regulator Bcl-2 was repressed, while apoptosis regulator BAX expression was enhanced by miR-486-5p mimic transfection. Notably, the effects of miR-486-5p mimic on hHSFs were significantly eliminated by Smad2 plasmid transfection. Taken together, these results demonstrated that miR-486-5p inhibited the proliferation, induced apoptosis and increased G1/S phase arrest of hHSFs by targeting Smad2. miR-486-5p may be a promising therapeutic target for HS management.

10‑Hydroxycamptothecin induces apoptosis in human fibroblasts by regulating miRNA‑23b‑3p expression

10-Hydroxycamptothecin (HCPT) effectively controls epidural fibrosis, but the exact underlying mechanisms remain ambiguous. Abnormal microRNA (miR)-23b-3p expression has been detected in various types of fibrotic tissues that are present in different diseases. The aim of the present study was to elucidate the mechanisms through which HCPT induces fibroblast apoptosis. Reverse transcription-quantitative polymerase chain reactions were performed on six traumatic scar samples and matched normal skin samples; traumatic scar formation was revealed to be significantly inversely associated with miR-23b-3p expression. In addition, the miR-23b-3p expression level in human fibroblasts was examined following HCPT treatment. The effects of HCPT and miR-23b-3p on fibroblast apoptosis were assessed using terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling, flow cytometry and western blot analysis. The results demonstrated that HCPT treatment notably increased miR-23b-3p expression levels and accelerated fibroblast apoptosis. Therefore, upregulation of miR-23b-3p expression was demonstrated to promote fibroblast apoptosis, consistently with the effects of HCPT. The results of the present study indicated that HCPT may induce fibroblast apoptosis by regulating miR-23b-3p expression.

Integrative Analyses of Genes Associated with Subcutaneous Insulin Resistance

Insulin resistance is present in the majority of patients with non-insulin-dependent diabetes mellitus (NIDDM) and obesity. In this study, we aimed to investigate the key genes and potential molecular mechanism in insulin resistance. Expression profiles of the genes were extracted from the Gene Expression Omnibus (GEO) database. Pathway and Gene Ontology (GO) enrichment analyses were conducted at Enrichr. The protein–protein interaction (PPI) network was settled and analyzed using the Search Tool for the Retrieval of Interacting Genes (STRING) database constructed by Cytoscape software. Modules were extracted and identified by the PEWCC1 plugin. The microRNAs (miRNAs) and transcription factors (TFs) which control the expression of differentially expressed genes (DEGs) were analyzed using the NetworkAnalyst algorithm. A database (GSE73108) was downloaded from the GEO databases. Our results identified 873 DEGs (435 up-regulated and 438 down-regulated) genetically associated with insulin resistance. The pathways which were enriched were pathways in complement and coagulation cascades and complement activation for up-regulated DEGs, while biosynthesis of amino acids and the Notch signaling pathway were among the down-regulated DEGs. Showing GO enrichment were cardiac muscle cell–cardiac muscle cell adhesion and microvillus membrane for up-regulated DEGs and negative regulation of osteoblast differentiation and dendrites for down-regulated DEGs. Subsequently, myosin VB (MYO5B), discs, large homolog 2(DLG2), axin 2 (AXIN2), protein tyrosine kinase 7 (PTK7), Notch homolog 1 (NOTCH1), androgen receptor (AR), cyclin D1 (CCND1) and Rho family GTPase 3 (RND3) were diagnosed as the top hub genes in the up- and down-regulated PPI network and modules. In addition, GATA binding protein 6 (GATA6), ectonucleotide pyrophosphatase/phosphodiesterase 5 (ENPP5), cyclin D1 (CCND1) and tubulin, beta 2A (TUBB2A) were diagnosed as the top hub genes in the up- and down-regulated target gene–miRNA network, while tubulin, beta 2A (TUBB2A), olfactomedin-like 1 (OLFML1), prostate adrogen-regulated mucin-like protein 1 (PARM1) and aldehyde dehydrogenase 4 family, member A1 (ALDH4A1)were diagnosed as the top hub genes in the up- and down-regulated target gene–TF network. The current study based on the GEO database provides a novel understanding regarding the mechanism of insulin resistance and may provide novel therapeutic targets.

Hepatitis B virus X protein enhances hepatocarcinogenesis by depressing the targeting of NUSAP1 mRNA by miR-18b

Objective

The aim of this study was to investigate the underlying mechanism whereby HBx modulates the targeting of NUSAP1 by miR-18b to enhance hepatocarcinogenesis.

Methods

We employed an integrated approach of bioinformatics analysis and molecular experiments in hepatoma cells, HBV transgenic mice, and clinical liver cancer tissues to investigate the role of HBx-regulated miR-18b in the development of liver cancer.

Results

In this study, we report that the HBx-mediated tumor suppressor miR-18b modulates hepatocarcinogenesis during the host-HBV interaction. The expression levels of miR-18b were lower in clinical HBV-positive liver cancer tissues and liver tissues of HBV-transgenic mice. Interestingly, HBx inhibited miR-18b expression by inducing the methylation of CpG islands in its promoter. Accordingly, we tested the hypothesis that HBx enhanced hepatocarcinogenesis by increasing the expression of target genes of miR-18b. Moreover, we identified nucleolar spindle-associated protein 1 (NUSAP1) as one of the target genes of miR-18b. NUSAP1 was expressed at high levels in liver cancer tissues. Interestingly, HBx up-regulated NUSAP1 by suppressing miR-18b. Functionally, miR-18b significantly inhibited the proliferation of hepatoma cells by depressing NUSAP1 levels in vivo and in vitro.

Conclusions

Thus, we conclude that the targeting of NUSAP1 mRNA by the tumor suppressor miR-18b is controlled by HBx-modulated promoter methylation during the host-virus interaction, leading to hepatocarcinogenesis. Our findings provide new insights into the mechanism by which HBx-mediated miRNAs modulate hepatocarcinogenesis.

Hypermethylation of miR-205-5p by IR Governs Aggressiveness and Metastasis via Regulating Bcl-w and Src

Although radiotherapy has been successfully applied to treat many cancer types, surviving cancer cells often acquire therapeutic resistance, leading to increased risk of local recurrence and distant metastases via modification of the tumor microenvironment. Previously, we reported that high expression of Bcl-w in cancer patients is significantly correlated with poor survival as well as malignant activity. However, the relationship between ionizing radiation (IR)-induced resistance and Bcl-w expression in cancer cells is currently unclear. We showed that IR-induced Bcl-w contributes to EMT (epithelial-mesenchymal transition), migration, angiogenesis, stemness maintenance, and metastasis by promoting the expression of factors related to these phenotypes, both in vitro and in vivo. Meanwhile, IR enhanced hypermethylation of miR-205-5p CpG islands through Src activation, leading to decreased miR-205-5p expression and, in turn, potentially stimulating Bcl-w-mediated malignant activity and metastasis. The clinical applicability of Bcl-w and miR-205-5p from cells or animal models was confirmed using tissues and plasma of breast carcinoma patients. Based on the collective findings, we propose that miR-205-5ps as important negative mediators of resistance in radiotherapy could serve as useful potential targets of concurrently applied genetic therapy aimed to inhibit tumor aggressiveness and enhance the efficiency of radiotherapy in cancer patients.

Knockdown of Gene Expression in Macrophages by microRNA Mimic-Containing Poly (Lactic-co-glycolic Acid) Microparticles

Background: microRNA (miRNA) regulate target gene expression through translational repression and/or mRNA degradation and are involved in the regulation of inflammation. Macrophages are key inflammatory cells that are important in chronic inflammatory lung diseases such as cystic fibrosis (CF). Macrophage-expressed miRNA represent therapeutic drug targets, yet delivery of nucleic acids to macrophages has proved challenging. Methods: miRNAs were encapsulated in poly (lactic-co-glycolic acid) (PLGA)-based microparticles using double emulsion solvent evaporation and characterised for physicochemical features. Phorbol myristic acetate (PMA)-differentiated U937 macrophages were transfected with empty PLGA microparticles or those encapsulating a premiR-19b-3p or scrambled control miRNA mimic. miRNA internalisation and knockdown of a miR-19b-3p target gene, secretory leucoprotease inhibitor (SLPI), were determined by qRT-PCR. Results: Microparticle formulations were consistently found to be 2⁻3μm and all had a negative ζ potential (-5 mV to -14 mV). Encapsulation efficiency of premiR-19b-3p was 37.6 ± 13.4%. Levels of mature miR-19b-3p were higher in macrophages after delivery of premiR-19b-3p microparticles compared to empty or scrambled control miRNA-containing microparticles. Significant SLPI knockdown was achieved 72 hours post-delivery of premiR-19b-3p microparticles compared to controls. Conclusions: miRNA-encapsulating PLGA microparticles offer a new treatment paradigm for delivery to macrophages that could potentially be administered to CF lungs via inhalation.

Comprehensive Evolutionary Analysis of the Major RNA-Induced Silencing Complex Members

RNA-induced silencing complex (RISC) plays a critical role in small interfering RNA (siRNA) and microRNAs (miRNA) pathways. Accumulating evidence has demonstrated that the major RISC members (AGO, DICER, TRBP, PACT and GW182) represent expression discrepancies or multiple orthologues/paralogues in different species. To elucidate their evolutionary characteristics, an integrated evolutionary analysis was performed. Here, animal and plant AGOs were divided into three classes (multifunctional AGOs, siRNA-associated AGOs and piRNA-associated AGOs for animal AGOs and multifunctional AGOs, siRNA-associated AGOs and complementary functioning AGOs for plant AGOs). Animal and plant DICERs were grouped into one class (multifunctional DICERs) and two classes (multifunctional DICERs and siRNA-associated DICERs), respectively. Protista/fungi AGOs or DICERs were specifically associated with the siRNA pathway. Additionally, TRBP/PACT/GW182 were identified only in animals, and all of them functioned in the miRNA pathway. Mammalian AGOs, animal DICERs and chordate TRBP/PACT were found to be monophyletic. A large number of gene duplications were identified in AGO and DICER groups. Taken together, we provide a comprehensive evolutionary analysis, describe a phylogenetic tree-based classification of the major RISC members and quantify their gene duplication events. These findings are potentially useful for classifying RISCs, optimizing species-specific RISCs and developing research model organisms.

Effects of miR‑138‑5p and miR‑204‑5p on the migration and proliferation of gastric cancer cells by targeting EGFR

GC (gastric cancer) remains one of the most lethal malignancies worldwide. EGFR (epidermal growth factor receptor) plays an important role in the malignant process of GC, therefore, the present study addressed the relationship between EGFR and its potential regulators and examined their regulatory mechanisms in GC. We examined differences in the expression levels of EGFR in GC and adjacent non‑cancerous tissues. Bioinformatics analyses and dual luciferase reporter assays were used to confirm the putative relationship between miR‑138 or miR‑204 and EGFR, and their relationship was further detected using western blotting, RT‑PCR, and a series of cell studies. EGFR proteins were abundantly expressed in GC tissues, however EGFR mRNA levels remained indistinctive. Consequently, EGFR was revealed as a putative target of miR‑138 and miR‑204 which bound to the 3'UTR of EGFR mRNA. Further analysis revealed that miR‑138 and miR‑204 were significantly downregulated in GC tissues and the overexpression of miR‑138 and miR‑204 in GC cell lines resulted in the significant inhibition of EGFR protein levels and GC cell proliferation and metastasis. Rescue experiments confirmed that the roles of the two microRNAs were specific to EGFR. EGFR is a pivotal oncogene in GC progression that may be regulated by miR‑138 and miR‑204.

Differentially Expressed mRNA Targets of Differentially Expressed miRNAs Predict Changes in the TP53 Axis and Carcinogenesis-Related Pathways in Human Keratinocytes Chronically Exposed to Arsenic

Arsenic is a widely distributed toxic natural element. Chronic arsenic ingestion causes several cancers, especially skin cancer. Arsenic-induced cancer mechanisms are not well defined, but several studies indicate that mutation is not the driving force and that microRNA expression changes play a role. Chronic low arsenite exposure malignantly transforms immortalized human keratinocytes (HaCaT), serving as a model for arsenic-induced skin carcinogenesis. Early changes in miRNA expression in HaCaT cells chronically exposed to arsenite will reveal early steps in transformation. HaCaT cells were maintained with 0/100 nM NaAsO2 for 3 and 7 weeks. Total RNA was purified. miRNA and mRNA expression was assayed using Affymetrix microarrays. Targets of differentially expressed miRNAs were collected from TargetScan 6.2, intersected with differentially expressed mRNAs using Partek Genomic Suite software, and mapped to their pathways using MetaCore software. MDM2, HMGB1 and TP53 mRNA, and protein levels were assayed by RT-qPCR and Western blot. Numerous miRNAs and mRNAs involved in carcinogenesis pathways in other systems were differentially expressed at 3 and 7 weeks. A TP53 regulatory network including MDM2 and HMGB1 was predicted by the miRNA and mRNA networks. Total TP53 and TP53-S15-phosphorylation were induced. However, TP53-K382-hypoacetylation suggested that the induced TP53 is inactive in arsenic exposed cells. Our data provide strong evidence that early changes in miRNAs and target mRNAs may contribute to arsenic-induced carcinogenesis.

MicroRNAs in type 2 immunity

Type 2 immunity drives the pathology of allergic diseases and is necessary for expulsion of parasitic worms as well as having important implications in tumor progression. Over the last decade, a new research field has emerged describing a significant link between type 2 immunity and cancer development, called AllergoOncology. Thus, type 2 immune responses must be carefully regulated to mediate effective protection against damaging environmental factors, yet avoid excessive activation and immunopathology. Regulation of gene expression by microRNAs is required for normal behavior of most mammalian cells and has been studied extensively in the context of cancer. Although microRNA regulation of the immune system in cancer is well established and includes type 2 immune reactions in the tumor microenvironment, the involvement of microRNAs in these responses initiated by allergens, parasites or other environmental factors is just emerging. In this review, we focus on recent advances which increase the understanding of microRNA-mediated regulation of key mechanisms of type 2 immunity.

Microglia Polarization, Gene-Environment Interactions and Wnt/β-Catenin Signaling: Emerging Roles of Glia-Neuron and Glia-Stem/Neuroprogenitor Crosstalk for Dopaminergic Neurorestoration in Aged Parkinsonian Brain

Neuroinflammatory processes are recognized key contributory factors in Parkinson's disease (PD) physiopathology. While the causes responsible for the progressive loss of midbrain dopaminergic (mDA) neuronal cell bodies in the subtantia nigra pars compacta are poorly understood, aging, genetics, environmental toxicity, and particularly inflammation, represent prominent etiological factors in PD development. Especially, reactive astrocytes, microglial cells, and infiltrating monocyte-derived macrophages play dual beneficial/harmful effects, via a panel of pro- or anti-inflammatory cytokines, chemokines, neurotrophic and neurogenic transcription factors. Notably, with age, microglia may adopt a potent neurotoxic, pro-inflammatory “primed” (M1) phenotype when challenged with inflammatory or neurotoxic stimuli that hamper brain's own restorative potential and inhibit endogenous neurorepair mechanisms. In the last decade we have provided evidence for a major role of microglial crosstalk with astrocytes, mDA neurons and neural stem progenitor cells (NSCs) in the MPTP- (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-) mouse model of PD, and identified Wnt/β-catenin signaling, a pivotal morphogen for mDA neurodevelopment, neuroprotection, and neuroinflammatory modulation, as a critical actor in glia-neuron and glia-NSCs crosstalk. With age however, Wnt signaling and glia-NSC-neuron crosstalk become dysfunctional with harmful consequences for mDA neuron plasticity and repair. These findings are of importance given the deregulation of Wnt signaling in PD and the emerging link between most PD related genes, Wnt signaling and inflammation. Especially, in light of the expanding field of microRNAs and inflammatory PD-related genes as modulators of microglial-proinflammatory status, uncovering the complex molecular circuitry linking PD and neuroinflammation will permit the identification of new druggable targets for the cure of the disease. Here we summarize recent findings unveiling major microglial inflammatory and oxidative stress pathways converging in the regulation of Wnt/β-catenin signaling, and reciprocally, the ability of Wnt signaling pathways to modulate microglial activation in PD. Unraveling the key factors and conditons promoting the switch of the proinflammatory M1 microglia status into a neuroprotective and regenerative M2 phenotype will have important consequences for neuroimmune interactions and neuronal outcome under inflammatory and/or neurodegenerative conditions.

Long non-coding RNA BCYRN1 promotes the proliferation and metastasis of cervical cancer via targeting microRNA-138 in vitro and in vivo

Cervical cancer is one of the most malignant types of tumor and the fourth leading cause of cancer-associated mortality in females worldwide. High expression of brain cytoplasmic RNA 1 (BCYRN1) has been detected in various tumors. The present study aimed to investigate the effect of BCYRN1 in the viability and motility of cervical cancer, and the relevant mechanism. The results demonstrated that BCYRN1 was upregulated in cervical cancer tissues compared with normal tissues. Elevated levels of BCYRN1 were also detected in three human cervical cancer cell lines (SiHa, HeLa and CaSki) compared with non-cancerous ectocervical epithelial cell line (Ect1/E6E7). The expression of BCYRN1 was suppressed following transfection with small interfering RNA (siRNA) in HeLa cells. The silence of BCYRN1 significantly reduced cell viability and motility. Furthermore, microRNA (miR)-138 was predicted as a direct target of BCYRN1 and the expression of miR-138 was elevated in HeLa cells transfected with BCYRN1 siRNA. Subsequently, elevated levels of miR-138 were suppressed by transfection with miR-138 inhibitor in HeLa cells pretreated with BCYRN1 siRNA. The targeting association between BCYRN1 and miR-138 was supported by luciferase reporter assays. Additionally, BCYRN1 siRNA partially counteracted the effect of miR-138 inhibitor on promoting cell viability and mobility in HeLa cells. Finally, the in vivo experiment verified that BCYRN1 siRNA was able to prevent tumor growth, and reduced the expression of migration marker proteins metalloproteinase 2 and vascular endothelial cell growth factor, with enhanced expression levels of miR-138. These results suggest that lncRNA BCYRN1 promotes the proliferation and invasion of cervical cancer via targeting miR-138.

Supplemental Treatment for Huntington's Disease with miR-132 that Is Deficient in Huntington's Disease Brain

Huntington’s disease (HD) is an intractable neurodegenerative disorder caused by mutant Huntingtin (HTT) proteins that adversely affect various biomolecules and genes. MicroRNAs (miRNAs), which are functional small non-coding RNAs, are also affected by mutant HTT proteins. Here, we show amelioration in motor function and lifespan of HD-model mice, R6/2 mice, by supplying miR-132 to HD brains using a recombinant adeno-associated virus (rAAV) miRNA expression system. miR-132 is an miRNA related to neuronal maturation and function, but the level of miR-132 in the brain of R6/2 mice was significantly lower than that of wild-type mice. Our miR-132 supplemental treatment, i.e., supplying miR-132 to the brain, produced symptomatic improvement or retarded disease progression in R6/2 mice; interestingly, it had little effect on disease-causing mutant HTT mRNA expression and its products. Therefore, the findings suggest that there may be a therapeutic way to treat HD without inhibiting and/or repairing disease-causing HTT genes and gene products. Although miR-132 supplement may not be a definitive treatment for HD, it may become a therapeutic method for relieving HD symptoms and delaying HD progression.

Altered expression of microRNA during fracture healing in diabetic rats

OBJECTIVES

Diabetes mellitus (DM) is known to impair fracture healing. Increasing evidence suggests that some microRNA (miRNA) is involved in the pathophysiology of diabetes and its complications. We hypothesized that the functions of miRNA and changes to their patterns of expression may be implicated in the pathogenesis of impaired fracture healing in DM.

METHODS

Closed transverse fractures were created in the femurs of 116 rats, with half assigned to the DM group and half assigned to the control group. Rats with DM were induced by a single intraperitoneal injection of streptozotocin. At post-fracture days five, seven, 11, 14, 21, and 28, miRNA was extracted from the newly generated tissue at the fracture site. Microarray analysis was performed with miRNA samples from each group on post-fracture days five and 11. For further analysis, real-time polymerase chain reaction (PCR) analysis was performed at each timepoint.

RESULTS

Microarray analysis showed that there were 14 miRNAs at day five and 17 miRNAs at day 11, with a greater than twofold change in the DM group compared with the control group. Among these types of miRNA, five were selected based on a comparative and extended literature review. Real-time PCR analysis revealed that five types of miRNA (miR-140-3p, miR-140-5p, miR-181a-1-3p, miR-210-3p, and miR-222-3p) were differentially expressed with changing patterns of expression during fracture healing in diabetic rats compared with controls.

CONCLUSIONS

Our findings provide information to further understand the pathology of impaired fracture healing in a diabetic rat model. These results may allow the potential development of molecular therapy using miRNA for the treatment of impaired fracture healing in patients with DM.Cite this article: S. Takahara, S. Y. Lee, T. Iwakura, K. Oe, T. Fukui, E. Okumachi, T. Waki, M. Arakura, Y. Sakai, K. Nishida, R. Kuroda, T. Niikura. Altered expression of microRNA during fracture healing in diabetic rats. Bone Joint Res 2018;7:139-147. DOI: 10.1302/2046-3758.72.BJR-2017-0082.R1.

miR-204-5p suppresses hepatocellular cancer proliferation by regulating homeoprotein SIX1 expression

Fewer than 30% of patients with hepatocellular carcinoma (HCC) are eligible to receive curative therapies, and so a better understanding of the molecular mechanisms of HCC is needed to identify potential therapeutic targets. The role of microRNA (miRNA) in modulating tumour progression has been demonstrated, and therapies targeting miRNA appear promising. miR‐204‐5p has been shown to function in numerous types of cancer, but its role in HCC remains unclear. In this study, we found that miR‐204‐5p expression was downregulated in cancerous HCC tissues compared to nontumour tissues. Kaplan–Meier survival curve analysis also showed that low expression of miR‐204‐5p predicted worse outcomes of HCC patients. In addition, miR‐204‐5p expression was significantly lower in HCC cell lines. The function of miR‐204‐5p was also assessed both in vitro and in vivo. We demonstrated that ectopic expression of miR‐204‐5p in HCC cell lines inhibited HCC cell proliferation and clonogenicity using CCK8, BrdU and colony‐forming assays, while the inhibition of miR‐204‐5p enhanced proliferation and clonogenicity. Further in vivo studies in mice further confirmed the proliferation capacity of miR‐204‐5p. We also identified sine oculis homeobox homologue 1 (SIX1) as a direct target of miR‐204‐5p and showed that it was inversely correlated with miR‐204‐5p in both human and mouse HCC tissues. Transfection of miR‐204‐5p mimics in BEL‐7404 cells blocked the cell cycle by inhibiting the expression of cyclin‐D1 and cyclin‐A1, cell cycle‐related factors regulated by SIX1. More importantly, overexpression of the 3′UTR mutant SIX1 but not the wild‐type SIX1 abolished the suppressive effect of miR‐204‐5p, and downregulated SIX1 in BEL‐7402 cells that transfected with miR‐204 inhibitors could partly block the inhibitory effect of miR‐204‐5p on proliferation. Thus, we have demonstrated that miR‐204‐5p suppresses HCC proliferation by directly regulating SIX1 and its downstream factors.

Exosomes-Based Gene Therapy for MicroRNA Delivery

Despite recent advances in scientific knowledge and clinical practice, cardiovascular disease management and treatment remain a major burden. While several treatment strategies using drugs and surgeries are being developed for cardiovascular manifestations, gene-based therapies hold significant promise. Recent findings from our laboratory unveiled a novel mechanism that exosomes, secreted nanovesicles from stem cells, mediate cardiac repair via transferring their unique repertoire of microRNAs (miRNA) to recipient cells in the heart. Exosomes, unlike other vectors for gene delivery, present unique advantages such that exosomes are a cell-free natural system for ferrying RNA between cells, robust exosomal membrane can protect the RNA/gene of interest from digestion, and exosomes are rapidly taken up by target cells making them a more efficient vehicle for gene delivery. Here, we describe a stepwise protocol developed in our laboratory for generating exosomes from human CD34⁺ stem cells that carry exogenously applied Cy3 dye-labeled pre-miR miRNA precursors. We demonstrate that human CD34⁺ stem cell exosomes can rigorously enter into recipient cells and deliver Cy3 dye-labeled pre-miR miRNA precursors to regulate gene expression. Identification of key molecular targets to treat disease conditions is the foremost critical step and the novel approach presented here to generate exosomes carrying exogenous genetic information offers a valuable clinical tool for more effective treatment strategies.

Inhibition of the glucocorticoid receptor results in an enhanced miR-99a/100-mediated radiation response in stem-like cells from human prostate cancers

Radiation therapy is a major primary treatment option for both localized early stage prostate cancer, and for advanced, regionally un-resectable, cancer. However, around 30% of patients still experience biochemical recurrence after radiation therapy within 10 years. Thus, identification of better biomarkers and new targets are urgently required to improve current therapeutic strategies. The miR-99 family has been shown to play an important role in the regulation of the DNA damage response, via targeting of the SWI/SNF chromatin remodeling factors, SMARCA5 and SMARCD1 in cell line models. In the present study, we have demonstrated that low expression of miR-99a and miR-100 is present in cell populations which are relatively radiation insensitive, for example in prostate cancer stem cells and in castration-resistant prostate cancer. Additionally, treatment of cells with the synthetic glucocorticoid, Dexamethasone resulted in decreased miR-99a and 100 expression, suggesting a new mechanism of miR-99a and 100 regulation in androgen-independent prostate cells. Strikingly, treatment of prostate cells with the glucocorticoid receptor inhibitor, Mifepristone was found to sensitize prostate cells to radiation by increasing the levels of miR-99a and miR-100. These results qualify the miR99 family as markers of radiation sensitivity and as potential therapeutic targets to improve efficiency of radiotherapy.