MicroRNAs in the immune response

Identification and Characterization of the miRNA Transcriptome Controlling Green Pigmentation of Chicken Eggshells

Green eggs are mainly caused by inserting an avian endogenous retrovirus (EVA-HP) fragment into the SLCO1B3 gene. Although the genotypes for this insertion allele are consistent, eggshell color (ESC) may vary after a peak laying period; light-colored eggs are undesired by consumers and farmers and result in financial loss, so it is necessary to resolve this problem. miRNAs are small non-coding RNAs that exert essential functions in animal development and diseases. However, the regulatory miRNAs and detailed molecular mechanisms regulating eggshell greenness remain unclear. In the present study, we determined the genotype of green-eggshell hens through the detection of a homozygous allele insertion in the SLCO1B3 gene. The shell gland epithelium was obtained from green-eggshell hens that produced white and green shell eggs to perform transcriptome sequencing and investigate the important regulatory mechanisms that influence the ESC. Approximately 921 miRNAs were expressed in these two groups, which included 587 known miRNAs and 334 novel miRNAs, among which 44 were differentially expressed. There were 22 miRNAs that were significantly upregulated in the green and white groups, respectively, which targeted hundreds of genes, including KIT, HMOX2, and several solute carrier family genes. A Gene Ontology enrichment analysis of the target genes showed that the differentially expressed miRNA-targeted genes mainly belonged to the functional categories of homophilic cell adhesion, gland development, the Wnt signaling pathway, and epithelial tube morphogenesis. A KEGG enrichment analysis showed that the Hedgehog signaling pathway was significantly transformed in this study. The current study provides an overview of the miRNA expression profiles and the interaction between the miRNAs and their target genes. It provides valuable insights into the molecular mechanisms underlying green eggshell pigmentation, screening more effective hens to produce stable green eggs and obtaining higher economic benefits.

miRNA-Mediated Fine Regulation of TLR-Induced M1 Polarization

Macrophage polarization to the M1 spectrum is induced by bacterial cell wall components through stimulation of Toll-like family (TLR) receptors. By orchestrating the expression of relevant mediators of the TLR cascade, as well as associated pathways and feedback loops, macrophage polarization is coordinated to ensure an appropriate immune response. This is central to the successful control of pathogens and the maintenance of health. Macrophage polarization is known to be modulated at both the transcriptional and post-transcriptional levels. In recent years, the miRNA-based post-transcriptional regulation of M1 polarization has received increasing attention from the scientific community. Comparative studies have shown that TLR stimulation alters the miRNA profile of macrophages and that macrophages from the M1 or the M2 spectrum differ in terms of miRNAs expressed. Simultaneously, miRNAs are considered critical post-transcriptional regulators of macrophage polarization. In particular, miRNAs are thought to play a regulatory role in the switch between the early proinflammatory response and the resolution phase. In this review, we will discuss the current state of knowledge on the complex interaction of transcriptional and post-transcriptional regulatory mechanisms that ultimately determine the functionality of macrophages.

MicroRNA mediated regulation of oxidative stress and cytokines in Chlamydia trachomatis-infected recurrent spontaneous abortion: A case-control study

PROBLEM

Increased oxidative stress (OS) and inflammatory responses are major underlying factors behind Chlamydia trachomatis-associated recurrent spontaneous abortion (RSA). miRNAs are known to regulate inflammation and OS and their dysregulation has been associated with compromised pregnancies. Therefore, aim of this study was to investigate the expression/correlation of OS biomarkers, cytokines and miRNAs in C. trachomatis-associated RSA.

METHOD OF STUDY

Urine and non-heparinized blood samples were collected from RSA patients with history of >3 consecutive abortions (cases) and non-pregnant women with history of >2 successful deliveries (controls) attending Department of Obstetrics and Gynaecology, Safdarjung hospital, New Delhi. C. trachomatis detection was done in urine by PCR. miRNA expression was studied by microarray analysis and validated by real time-PCR. Evaluation of cytokines and antioxidant genes expression were done by real-time PCR. Level of OS biomarkers 8-hydroxy guanosine (8-OHdG) and 8-isporostane (8-IP) were measured by ELISA.

RESULTS

Fifty circulating miRNAs were differentially expressed in infected patients compared with controls. Of these, four were overexpressed and 46 downregulated. Thirteen differentially expressed circulating miRNAs were selected to validate microarray results. miRs-8069, -3663-3p showed maximum upregulation/downregulation in infected versus control group. Expression of cytokines (IL-8, TNF-α, IFN-γ), antioxidant genes SOD2 and OS biomarkers (8-OHdG,8-IP) were increased while SOD1 was decreased in infected patients. miR-8069 showed significant positive correlation with cytokines, SOD2, 8-OHdG and 8-IP. miR-3663-3p showed significant positive correlation with SOD1.

CONCLUSIONS

Overall results indicate circulating miRNAs are involved in pathogenesis of C. trachomatis-associated RSA and are potential modulators of cytokine signalling and OS in infected RSA.

Extracellular Vesicles Released from Macrophages Infected with Mycoplasma pneumoniae Stimulate Proinflammatory Response via the TLR2-NF-κB/JNK Signaling Pathway

Mycoplasma pneumoniae (M. pneumoniae, Mp) is an intracellular pathogen that causes pneumonia, tracheobronchitis, pharyngitis, and asthma in humans and can infect and survive in the host cells leading to excessive immune responses. Extracellular vesicles (EVs) from host cells carry components of pathogens to recipient cells and play a role in intercellular communication during infection. However, there is limited knowledge on whether EVs derived from M. pneumoniae-infected macrophages play as intercellular messengers and functional mechanisms. In this study, we establish a cell model of M. pneumoniae-infected macrophages that continuously secrete EVs to further asses their role as intercellular messengers and their functional mechanisms. Based on this model, we determined a method for isolating the pure EVs from M. pneumoniae-infected macrophages, which employs a sequence of operations, including differential centrifugation, filtering, and ultracentrifugation. We identified EVs and their purity using multiple methods, including electron microscopy, nanoparticle tracking analysis, Western blot, bacteria culture, and nucleic acid detection. EVs from M. pneumoniae-infected macrophages are pure, with a 30-200 nm diameter. These EVs can be taken up by uninfected macrophages and induce the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8 through the nuclear factor (NF)-κB, and mitogen-activated protein kinases (MAPK) signals pathway. Moreover, the expression of inflammatory cytokines induced by EVs relies on TLR2-NF-κB/JNK signal pathways. These findings will help us better understand a persistent inflammatory response and cell-to-cell immune modulation in the context of M. pneumoniae infection.

microRNA 146a ameliorates retinal damage in experimental autoimmune uveitis

Introduction

Uveitis and related intraocular inflammations are a major cause of blindness due to retinal damage caused by degeneration and loss of the photoreceptor cells. In mouse experimental autoimmune uveitis (EAU) previously we have shown mitochondrial oxidative stress with marked upregulation of αA crystallin in the inner segments of the photoreceptors. Furthermore, αA crystallin treatment prevented photoreceptor mitochondrial oxidative stress by suppressing innate and adaptive immunity in EAU.

Methods

Since these immune processes are modulated by microRNAs, in this study we investigated (a) modulation of microRNAs during development of EAU by αA crystallin administration and (b) microRNA therapeutic intervention.

Results

Few microRNAs were significantly upregulated in EAU mice with intravenous injection of αA crystallin and among these, computational bioinformatic analysis revealed that the upregulated microRNA 146a targets the innate and adaptive immune responses. In EAU, intravenous as well as intravitreal administration of this microRNA prevented inflammatory cell infiltration in uvea and retina and preserved photoreceptor cells.

Discussion

This protective function suggests that microRNA146a can be a novel therapeutic agent in preventing retinal damage in uveitis.

Chronic nicotine exposure alters sperm small RNA content in C57BL/6J mouse model

Multigenerational inheritance is a nongenomic form of heritability characterized by altered phenotypes in the first generation born from the exposed parent. Multigenerational factors may account for inconsistencies and gaps in heritable nicotine addiction vulnerability. Our lab previously found that F1 offspring of male C57BL/6J mice chronically exposed to nicotine exhibited altered hippocampus functioning and related learning, nicotine-seeking, nicotine metabolism, and basal stress hormones. In an effort to identify germline mechanisms underlying these multigenerational phenotypes, the current study sequenced small RNA extracted from sperm of males chronically administered nicotine using our previously established exposure model. We identified 16 miRNAs whose expression in sperm was dysregulated by nicotine exposure. A literature review of previous research on these transcripts suggested an enrichment for regulation of psychological stress and learning. mRNAs predicted to be regulated by differentially expressed sperm small RNAs were further analyzed using exploratory enrichment analysis, which suggested potential modulation of pathways related to learning, estrogen signaling, and hepatic disease, among other findings. Overall, our findings point to links between nicotine-exposed F0 sperm miRNA and altered F1 phenotypes in this multigenerational inheritance model, particularly F1 memory, stress, and nicotine metabolism. These findings provide a valuable foundation for future functional validation of these hypotheses and characterization of mechanisms underlying male-line multigenerational inheritance.

Attenuated Negative Feedback in Monocyte-Derived Macrophages From Persons Living With HIV: A Role for IKAROS

Persons living with HIV (PLWH) are at higher risk of developing secondary illnesses than their uninfected counterparts, suggestive of a dysfunctional immune system in these individuals. Upon exposure to pathogens, monocytes undergo epigenetic remodeling that results in either a trained or a tolerant phenotype, characterized by hyper-responsiveness or hypo-responsiveness to secondary stimuli, respectively. We utilized CD14⁺ monocytes from virally suppressed PLWH and healthy controls for in vitro analysis following polarization of these cells toward a pro-inflammatory monocyte-derived macrophage (MDM) phenotype. We found that in PLWH-derived MDMs, pro-inflammatory signals (TNFA, IL6, IL1B, miR-155-5p, and IDO1) dominate over negative feedback signals (NCOR2, GSN, MSC, BIN1, and miR-146a-5p), favoring an abnormally trained phenotype. The mechanism of this reduction in negative feedback involves the attenuated expression of IKZF1, a transcription factor required for de novo synthesis of RELA during LPS-induced inflammatory responses. Furthermore, restoring IKZF1 expression in PLWH-MDMs partially reinstated expression of negative regulators of inflammation and lowered the expression of pro-inflammatory cytokines. Overall, this mechanism may provide a link between dysfunctional immune responses and susceptibility to co-morbidities in PLWH with low or undetectable viral load.

MicroRNAs and Related Cytokine Factors Quickly Respond in the Immune Response of Channel Catfish to Lipopolysaccharides and β-Glucan Stimulation

MicroRNAs (miRNAs) are well-known as powerful regulators of gene expression, with their potential to serve for immunology widely researched in mammals and birds but rarely in fishes. To better understand fish immunology behavior, we herein investigated nine immune-related miRNAs that were reported in other animals, as well as five related cytokine factors and lysozyme (LZM) in the liver, anterior kidney, and spleen of Channel Catfish Ictalurus punctatus after being stimulated by lipopolysaccharides (LPS) and β-glucan. We also predicated the potential targets of these miRNAs via bioinformatics and further investigated nine of them via quantitative real-time PCR. Results showed that expressions of the nine miRNAs were quickly changed in varying extent after stimulation by LPS, especially for miR-122, miR-142a, miR-155, and miR-223, which were significantly changed in spleen, and the same occurred for the LZM and three cytokine factors TNF-α, IFN-γ and TLR2. Compared with LPS, although most of the miRNAs and the cytokine genes were also affected by β-glucan, the extent of the effect was weak. Bioinformatics analysis revealed many immune-related targets of the miRNAs, with some of them reported by previous studies. For the nine investigated target genes, seven targets (77.8%) were significantly upregulated after the stimulation of LPS. It therefore can be inferred that the immune-related miRNAs, LZM, and cytokine factors elicited quick immune responses of Channel Catfish to LPS stimulation as in other animals, but the regulation mechanism of miRNAs might be complex and diverse. This research will contribute to a better understanding will support further immunology research in fishes.

ImmReg: the regulon atlas of immune-related pathways across cancer types

Immune system gene regulation perturbation has been found to be a major cause of the development of various types of cancer. Numbers of mechanisms contribute to gene expression regulation, thus, systematically identification of potential regulons of immune-related pathways is critical to cancer immunotherapy. Here, we comprehensively chart the landscape of transcription factors, microRNAs, RNA binding proteins and long noncoding RNAs regulation in 17 immune-related pathways across 33 cancers. The potential immunology regulons are likely to exhibit higher expressions in immune cells, show expression perturbations in cancer, and are significantly correlated with immune cell infiltrations. We also identify a panel of clinically relevant immunology regulons across cancers. Moreover, the regulon atlas of immune-related pathways helps prioritizing cancer-related genes (i.e. ETV7, miR-146a-5p, ZFP36 and HCP5). We further identified two molecular subtypes of glioma (cold and hot tumour phenotypes), which were characterized by differences in immune cell infiltrations, expression of checkpoints, and prognosis. Finally, we developed a user-friendly resource, ImmReg (http://bio-bigdata.hrbmu.edu.cn/ImmReg/), with multiple modules to visualize, browse, and download immunology regulation. Our study provides a comprehensive landscape of immunology regulons, which will shed light on future development of RNA-based cancer immunotherapies.

Using Omics Approaches in the Discovery of Biomarkers for Early Diagnosis of Johne's Disease in Sheep and Goats

Simple Summary

Johne’s disease (JD) is caused by Mycobacterium avium subsp. paratuberculosis (MAP) and is an important and emerging problem in livestock. Most JD research has been carried out on cattle, but interest in the pathogenesis and diagnosis of this disease in sheep and goats is greatest in developing countries. Sheep and goats are also a relevant part of livestock production in Europe and Australia, and these species provide an excellent resource to study and better understand the mechanism of survival of MAP and gain insights into possible approaches to control this disease. This review gives an overview of the literature on paratuberculosis in sheep and goats, highlighting the immunological aspects and the potential for “omics” approaches to identify effective biomarkers for the early detection of infection.

Abstract

Johne’s disease (JD) is caused by Mycobacterium avium subsp. paratuberculosis (MAP) and is an important and emerging problem in livestock; therefore, its control and prevention is a priority to reduce economic losses and health risks. Most JD research has been carried out on cattle, but interest in the pathogenesis and diagnosis of this disease in sheep and goats is greatest in developing countries. Sheep and goats are also a relevant part of livestock production in Europe and Australia, and these species provide an excellent resource to study and better understand the mechanism of survival of MAP and gain insights into possible approaches to control this disease. This review gives an overview of the literature on paratuberculosis in sheep and goats, highlighting the immunological aspects and the potential for “omics” approaches to identify effective biomarkers for the early detection of infection. As JD has a long incubation period before the disease becomes evident, early diagnosis is important to control the spread of the disease.

BCG vaccination-induced emergency granulopoiesis provides rapid protection from neonatal sepsis

Death from sepsis in the neonatal period remains a serious threat for millions. Within 3 days of administration, bacille Calmette-Guérin (BCG) vaccination can reduce mortality from neonatal sepsis in human newborns, but the underlying mechanism for this rapid protection is unknown. We found that BCG was also protective in a mouse model of neonatal polymicrobial sepsis, where it induced granulocyte colony-stimulating factor (G-CSF) within hours of administration. This was necessary and sufficient to drive emergency granulopoiesis (EG), resulting in a marked increase in neutrophils. This increase in neutrophils was directly and quantitatively responsible for protection from sepsis. Rapid induction of EG after BCG administration also occurred in three independent cohorts of human neonates.

Role of circulating miR 194-5p, miR 106b, and miR 146a as potential biomarkers for epilepsy: a case-control study

Background

Epilepsy is a chronic neurological disease. A suitable biomarker for epilepsy diagnosis remains lacking. MicroRNAs (miRNAs) were pronounced as promising biomarkers for epileptogenesis.

Objectives

To analyze the expression levels of miR 194-5p, miR 106b, and miR 146a in Egyptian epileptic patients compared to control subjects and to detect their correlation to clinical characteristics.

Subjects and methods

We evaluated the expression levels of miR 106b, miR 146a, and miR 194-5p using real-time quantitative polymerase chain reaction (qRT-PCR) in 50 subjects: 15 patients with idiopathic generalized epilepsy, 15 patients with focal epilepsy (3 idiopathic and 12 cryptogenic), and 20 healthy controls.

Results

miR 106b and miR 194-5p were upregulated in the generalized epilepsy group compared to control; miR 194-5p was significantly downregulated in the focal epilepsy group compared to the generalized epilepsy group and control (p ˂ 0.05). miR 194-5p was negatively correlated to disease duration in patients with focal epilepsy; the three microRNAs were positively correlated to each other (p ˂ 0.05).

Conclusion

Serum miR 194-5P and miR 106b can be used as potential non-invasive biomarkers in the evaluation of idiopathic generalized epilepsy.

Biomechanical signal communication in vascular smooth muscle cells

Biomechanical stresses are closely associated with cardiovascular development and diseases. In vivo, vascular smooth muscle cells are constantly stimulated by biomechanical factors caused by increased blood pressure leading to the non-specific activation of cell transmembrane proteins. Thus, various intracellular signal molecules are simultaneously activated via signaling cascades, which are closely related to alterations in the differentiation, phenotype, inflammation, migration, pyroptosis, calcification, proliferation, and apoptosis of vascular smooth muscle cells. Meanwhile, mechanical stress-induced miRNAs and epigenetics modification on vascular smooth muscle cells play critical roles as well. Eventually, the overall pathophysiology of the cells is altered, resulting in the development of many major clinical diseases, including hypertension, atherosclerosis, grafted venous atherosclerosis, and aneurysm, among others. In this paper, important advances in mechanical signal communication in vascular smooth muscle cells are reviewed.

Differential expression of miRNAs and their target genes: Exploring a new perspective of acquired aplastic anemia pathogenesis

INTRODUCTION

MicroRNAs (miRNAs) play a critical role in orchestrating T cell differentiation and activation and may thus play a vital role in acquired aplastic anemia (aAA). The study aimed to evaluate the differential expression of selected miRNAs and their relevant target genes in bone marrow samples of aAA patients.

METHODS

Differential expression of 8 miRNAs viz; hsa-miR-126-3p, miR-145-5p, miR-155-5p, miR-150-5p, miR-146b-5p, miR-34a, miR-29a, and miR-29b was evaluated in the bone marrow mononuclear cells of aAA patients. TaqMan microRNA assay was performed for preparing the cDNA of specific miRNA, followed by expression analysis using qRT-PCR. Data were normalized using two endogenous controls, RNU6B and RNU48. Delta-delta CT method was used to calculate the fold change (FC) of miRNA expression in individual samples, and a FC of >1.5 was taken as significant. Target genes of these miRNAs were evaluated by qRT-PCR.

RESULTS

Thirty five samples of aAA patients and 20 controls were evaluated. Irrespective of the disease severity, five miRNAs were found to be deregulated; miR-126 (FC-0.348; P-value-.0001) and miR-145 (FC-0.31; P-value-.0001) were downregulated, while miR-155 (FC-3.50; P-value-.0067), miR-146 (FC-3.13; P-value-.0105), and miR-150 (FC-5.78; P-value-.0001) were upregulated. Target gene study revealed an upregulation of PIK3R2, MYC, SOCS1, and TRAF-6, and downregulation of MYB.

CONCLUSION

This is the first study from the Indian subcontinent demonstrating the presence of altered miRNA expression in the bone marrow samples of aAA patients, suggesting their role in the pathogenesis of the disease. A comprehensive study focusing on the effect of these miRNA-mRNA interactions is likely to open new avenues of management.

Unraveling the Role of MicroRNAs in Mycobacterium tuberculosis Infection and Disease: Advances and Pitfalls

Tuberculosis (TB) is an infectious disease of extremely high epidemiological burden worldwide that is easily acquired through the inhalation of infected respiratory droplets. The complex pathogenesis of this infection spans from subjects never developing this disease despite intense exposure, to others in which immune containment fails catastrophically and severe or disseminated forms of disease ensue. In recent decades, microRNAs (miRNAs) have gained increasing attention due to their role as gene silencers and because of their altered expression in diverse human diseases, including some infections. Recent research regarding miRNAs and TB has revealed that the expression profile for particular miRNAs clearly changes upon Mycobacterium tuberculosis infection and also varies in the different stages of this disease. However, despite the growing number of studies-some of which have even proposed some miRNAs as potential biomarkers-methodological variations and key differences in relevant factors, such as sex and age, cell type analyzed, M. tuberculosis strain, and antimicrobial therapy status, strongly hinder the comparison of data. In this review, we summarize and discuss the literature and highlight the role of selected miRNAs that have specifically and more consistently been associated with M. tuberculosis infection, together with a discussion of the possible gene and immune regulation pathways involved.

Dietary Immunostimulant CpG Modulates MicroRNA Biomarkers Associated with Immune Responses in Atlantic Salmon (Salmo salar)

MicroRNAs (miRNAs) are key regulators in fish immune responses. However, no study has previously characterized the impact of polyriboinosinic polyribocytidylic acid (pIC) and formalin-killed typical Aeromonas salmonicida (ASAL) on miRNA expression in Atlantic salmon fed a commercial diet with and without immunostimulant CpG. To this end, first, we performed small RNA deep sequencing and qPCR analyses to identify and confirm pIC- and/or ASAL-responsive miRNAs in the head kidney of salmon fed a control diet. DESeq2 analyses identified 12 and 18 miRNAs differentially expressed in pIC and ASAL groups, respectively, compared to the controls. Fifteen of these miRNAs were studied by qPCR; nine remained significant by qPCR. Five miRNAs (miR-27d-1-2-5p, miR-29b-2-5p, miR-146a-5p, miR-146a-1-2-3p, miR-221-5p) were shown by qPCR to be significantly induced by both pIC and ASAL. Second, the effect of CpG-containing functional feed on miRNA expression was investigated by qPCR. In pre-injection samples, 6 of 15 miRNAs (e.g., miR-181a-5-3p, miR-462a-3p, miR-722-3p) had significantly lower expression in fish fed CpG diet than control diet. In contrast, several miRNAs (e.g., miR-146a-1-2-3p, miR-192a-5p, miR-194a-5p) in the PBS- and ASAL-injected groups had significantly higher expression in CpG-fed fish. Multivariate statistical analyses confirmed that the CpG diet had a greater impact on miRNA expression in ASAL-injected compared with pIC-injected fish. This study identified immune-relevant miRNA biomarkers that will be valuable in the development of diets to combat infectious diseases of salmon.

MiR-183 delivery attenuates murine lupus nephritis-related injuries via targeting mTOR

MicroRNAs (miRNAs) play a vital role in the occurrence and development of many human diseases, including systemic lupus erythematosus (SLE). SLE is an autoimmune disease characterized by the production of autoantibodies against nuclear antigens and multiorgan involvement. Study of miRNAs involved in SLE provides new insights into the pathogenesis of SLE and might lead to the identification of new therapeutic interventions. The aim of this study was to investigate the effect of miR-183 injection on the progression of SLE by using MRL/lpr mouse model. The expression levels of miR-183 and mTOR mRNA were detected by quantitative real-time PCR assay. The effect of miR-183 on the course of spontaneous disease progression in the MRL/lpr mice was examined by intraperitoneal injection of miR-183 into mice and followed by monitoring lifespan, anti-dsDNA antibody levels, urinary albumin levels, blood urea nitrogen (BUN) levels, and Tregs and Th17 cell population. We found that miR-183 injection resulted in reduction of anti-DNA antibody and immune complex component levels, restoration of Tregs and Th17 cell population and prolongation of survival. Our findings suggest that miR-183 injection may serve as an effective therapeutic treatment for delaying or easing pathologic features of SLE.

MicroRNA Expression Profiles in External Cervical Resorption

INTRODUCTION

External cervical resorption (ECR) has been challenging for its diagnosis, prevention, and treatment. Its etiology and pathogenesis are largely unknown. This study characterized microRNA (miRNA) expression patterns of human tissues from ECR lesions and identified potential messenger RNA targets and pathways.

METHODS

Granulomatous tissues from ECR (n = 5) and their adjacent nonaffected asymptomatic gingival connective tissues (n = 5) were collected. Similarly, chronic periodontitis (CP) and control samples were collected (n = 3). Quantitative reverse transcription polymerase chain reaction array analysis compared the expression profiles of 88 miRNAs between diseases. Differentially expressed miRNAs were identified using the Student t test. Bioinformatics for messenger RNA (miRWalk) and KEGG pathway analyses were performed to identify predicted target genes and biological/cellular functions and signaling pathways.

RESULTS

Three miRNAs (miR-20a-5p, miR-210-3p, and miR-99a-4p) were significantly down-regulated and 1 miRNA (miR-122-5p) was significantly up-regulated in ECR (P < .05). One up-regulated and 1 down-regulated miRNA reached the significance threshold in CP. A comparison of miRNA expression in ECR and CP identified 3 differentially expressed miRNAs, indicating differences in disease pathobiology. Inflammation-associated Wnt, PI3K-Akt, mitogen-activated protein kinases signaling, and bone formation-associated transforming growth factor beta pathways were identified and predicted to be modulated by differentially expressed miRNAs in both ECR and CP. Biological processes unique to each disease entity were identified, such as T- and B-cell receptor signaling pathways, osteoclast differentiation, and extracellular matrix-receptor interaction for CP. Glycosaminoglycan biosynthesis, mineral absorption, and insulin signaling pathways for ECR were identified.

CONCLUSIONS

This proof-of-principle in vivo study indicated that ECR has both common and unique miRNA expression profiles in comparison with CP, which are predicted to target genes regulating inflammation, immunity, and metabolism of mineralized tissues.

Resveratrol-Mediated Attenuation of Staphylococcus aureus Enterotoxin B-Induced Acute Liver Injury Is Associated With Regulation of microRNA and Induction of Myeloid-Derived Suppressor Cells

Resveratrol (RES) is a polyphenolic compound found abundantly in plant products including red grapes, peanuts, and mulberries. Because of potent anti-inflammatory properties of RES, we investigated whether RES can protect from Staphylococcal enterotoxin B (SEB)-induced acute liver injury in mice. SEB is a potent super antigen that induces robust inflammation and releases inflammatory cytokines that can be fatal. We observed that SEB caused acute liver injury in mice with increases in enzyme aspartate transaminase (AST) levels, and massive infiltration of immune cells into the liver. Treatment with RES (100 mg/kg body weight) attenuated SEB-induced acute liver injury, as indicated by decreased AST levels and cellular infiltration in the liver. Interestingly, RES treatment increased the number of myeloid derived suppressor cells (MDSCs) in the liver. RES treatment led to alterations in the microRNA (miR) profile in liver mononuclear cells (MNCs) of mice exposed to SEB, and pathway analysis indicated these miRs targeted many inflammatory pathways. Of these, we identified miR-185, which was down-regulated by RES, to specifically target Colony Stimulating Factor (CSF1) using transfection studies. Moreover, the levels of CSF1 were significantly increased in RES-treated SEB mice. Because CSF1 is critical in MDSC induction, our studies suggest that RES may induce MDSCs by down-regulating miR-185 leading to increase the expression of CSF1. The data presented demonstrate for the first time that RES can effectively attenuates SEB-induced acute liver injury and that this may result from its action on miRs and induction of MDSCs.

Alpinetin exerts anti-colitis efficacy by activating AhR, regulating miR-302/DNMT-1/CREB signals, and therefore promoting Treg differentiation

Alpinetin, a flavonoid compound extracted from the seeds of Alpinia katsumadai Hayata, has been demonstrated to exert massive biological properties. This study aimed to evaluate the effect of alpinetin on dextran sulfate sodium (DSS)-induced colitis, and elucidate the potential mechanisms. Alpinetin significantly alleviated colitis in mice, accompanied with restored Th17/Treg balance in colons. In vitro, alpinetin directly promoted Treg differentiation but exerted little effect on Th17 differentiation, and the action was in an aryl hydrocarbon receptor (AhR)-dependent manner. It acted as a potential AhR activator, evidenced by increased expression of CYP1A1, dissociation of AhR/HSP90 complexes, AhR nuclear translocation, XRE-driven luciferase reporter gene and DNA-binding activity of AhR/ARNT/XRE in T cells. Furthermore, alpinetin significantly promoted expression of miR-302 but not others, and restrained expression of DNMT-1 and methylation level of Foxp3 promoter region in CD4⁺ T cells and colons of colitis mice. However, the association of CREB and Foxp3 promoter region but not expression, nuclear translocation and DNA-binding activity of CREB was up-regulated by alpinetin in CD4⁺ T cells. The relationship of alpinetin-adjusted AhR activation, expressions of miR-302 and DNMT-1, association of CREB and Foxp3 promoter region, and Treg differentiation was confirmed by using CH223191, siAhR, miR-302 inhibitor and pcDNA3.1(+)-mDNMT-1. Finally, CH223191 abolished the amelioration of alpinetin on colitis, induction of Treg cells and regulation of miR-302/DNMT-1/CREB signals in colons of colitis mice. In conclusion, alpinetin ameliorated colitis in mice via activating AhR, regulating miR-302/DNMT-1/CREB signals, therefore promoting Treg differentiation.

MiRNA-155 Regulates the Th17/Treg Ratio by Targeting SOCS1 in Severe Acute Pancreatitis

Acute pancreatitis (AP) is a serious condition associated with intestinal barrier disruption or inflammation of the pancreatic tissue. Specific microRNAs are involved in the pathogenesis of AP, during which IL-17-producing CD4⁺ T helper (Th17) cells accumulate in the pancreas. In this study, significantly increased levels of miR-155 were detected in clinical samples from patients with AP, and overexpression of miR-155 correlated with severe AP (SAP). To identify the effect of miR-155 on T cell differentiation, we isolated CD4⁺ T lymphocytes and in vitro experiments showed that inhibition of miR-155 significantly reversed the stress-induced increase in the Th17/Treg ratio. The results also showed that miR-155 increased the Th17-mediated inflammatory response by targeting SOCS1. The interaction between miR-155 and the 3^′-UTR of SOCS1 was confirmed by a dual luciferase reporter assay and RT-PCR. Experimental AP of varying severity was induced in BALB/c mice by caerulein hyperstimulation and miR-155 expression was found to increase with disease progression. Inhibition of miR-155 expression significantly improved the pathology of the pancreas. We also observed downregulation of expression of inflammatory factors, IL-17, SOCS1 and phosphorylated STAT1 after miR-155 inhibition. In summary, miR-155 regulates the Th17/Treg ratio by targeting SOCS1, most probably via direct binding to its 3^′-UTR region, indicating that this microRNA may be a potential biomarker and/or therapeutic target for AP.

MicroRNA Regulation of Host Immune Responses following Fungal Exposure

Fungal bioaerosols are ubiquitous in the environment and human exposure can result in a variety of health effects ranging from systemic, subcutaneous, and cutaneous infections to respiratory morbidity including allergy, asthma, and hypersensitivity pneumonitis. Recent research has focused on the role of microRNAs (miRNAs) following fungal exposure and is overlooked, yet important, group of regulators capable of influencing fungal immune responses through a variety of cellular mechanisms. These small non-coding ribose nucleic acids function to regulate gene expression at the post-transcriptional level and have been shown to participate in multiple disease pathways including cancer, heart disease, apoptosis, as well as immune responses to microbial hazards and occupational allergens. Recent animal model studies have characterized miRNAs following the exposure to inflammatory stimuli. Studies focused on microbial exposure, including bacterial infections, as well as exposure to different allergens have shown miRNAs, such as miR-21, miR-146, miR-132, miR-155, and the let-7 family members, to be involved in immune and inflammatory responses. Interestingly, the few studies have assessed that the miRNA profiles following fungal exposure have identified the same critical miRNAs that have been characterized in other inflammatory-mediated and allergy-induced experimental models. Review of available in vitro, animal and human studies of exposures to Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Paracoccidioides brasiliensis, and Stachybotrys chartarum identified several miRNAs that were shared between responses to these species including miR-125 a/b (macrophage polarization/activation), miR-132 [toll-like receptor (TLR)2-mediated signaling], miR-146a (TLR mediated signaling, alternative macrophage activation), and miR-29a/b (natural killer cell function, C-leptin signaling, inhibition of Th1 immune response). Although these datasets provide preliminary insight into the role of miRNAs in fungal exposed models, interpretation of miRNA datasets can be challenging for researchers. To assist in navigating this rapidly evolving field, the aim of this review is to describe miRNAs in the framework of host recognition mechanisms and provide initial insight into the regulatory pathways in response to fungal exposure.

Discovery of microRNAs associated with the antiviral immune response of Atlantic cod macrophages

MicroRNAs (miRNAs) are known to play important immunoregulatory roles in teleosts, although miRNAs involved in the antiviral immune response of Atlantic cod (Gadus morhua) were previously uncharacterised. Using deep sequencing and qPCR, the present study was conducted to identify miRNAs responsive to the viral mimic, polyriboinosinic polyribocytidylic acid (pIC) in Atlantic cod macrophages. Macrophage samples isolated from Atlantic cod (n=3) and treated with pIC or phosphate buffered saline (PBS control) for 24 and 72h were used for miRNA profiling. Following deep sequencing, DESeq2 analyses identified four (miR-731-3p, miR-125b-3-3p, miR-150-3p and miR-462-3p) and two (miR-2188-3p and miR-462-3p) significantly differentially expressed miRNAs at 24 and 72h post-stimulation (HPS), respectively. Sequencing-identified miRNAs were subjected to qPCR validation using a larger number of biological replicates (n=6) exposed to pIC or PBS over time (i.e. 12, 24, 48 and 72 HPS). As in sequencing, miR-731-3p, miR-462-3p and miR-2188-3p showed significant up-regulation by pIC. The sequencing results were not qPCR-validated for miR-125b-3-3p and miR-150-3p as up- and down-regulated miRNAs at 24 HPS, respectively; however, qPCR results showed significant up-regulation in response to pIC stimulation at later time points (i.e. 48 and/or 72 HPS). We also used qPCR to assess the expression of other miRNAs that were previously shown as immune responsive in other vertebrates. qPCR results at 48 and/or 72 HPS revealed that miR-128-3-5p, miR-214-1-5p and miR-451-3p were induced by pIC, whereas miR-30b-3p and miR-199-1-3p expression were repressed in response to pIC. The present study identified ten pIC-stimulated miRNAs, suggesting them as important in antiviral immune responses of Atlantic cod macrophages. Some pIC-responsive miRNAs identified in this study were predicted to target putative immune-related genes of Atlantic cod (e.g. miR-30b-3p targeting herc4), although the regulatory functions of these miRNAs need to be validated by future studies.

TNF-α mRNA is negatively regulated by microRNA-181a-5p in maturation of dendritic cells induced by high mobility group box-1 protein

Dendritic cell (DC) can be stimulated by both exogenous pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS) and endogenous damage-associated molecular patterns (DAMPs) such as high mobility group box-1 protein (HMGB1). MicroRNAs (miRNAs) act as post-transcriptional fine tuners of mRNA. Studies have focused mostly on the potential role of miRNAs in DCs maturation triggered by PAMPs, especially LPS, however, little is known about the regulatory mechanism underlying the effects of miRNAs in DC maturation mediated by DAMPs, including HMGB1. Here, we first profiled a miRNA microarray of DCs stimulated by HMGB1 and determined that the up-regulated miRNA miR-181a-5p may act as a regulatory miRNA in these cells. Computational algorithms predicted TNF-α 3'UTR to be targeted by miR-181a-5p, which was confirmed by the experiments involving luciferase reporters. In addition, we found that TNF-α mRNA was down-regulated by miR-181a-5p mimic, and significantly up-regulated by miR-181a-5p inhibitor. Taken together, we identified miR-181a-5p a negative regulator in HMGB1-induced immune responses by targeting TNF-α mRNA in DCs. Moreover, we suggested that miR-181a-5p may play a role in regulating DC responses to HMGB1 and serve as evidence indicating that novel therapies targeting miRNAs may be useful for treating immune dysfunction in the setting of sepsis.

Correlation of the expression of miR-146a in peripheral blood mononuclear cells of patients with ankylosing spondylitis and inflammatory factors

We investigated the expression of miR-146a in peripheral blood mononuclear cell (PBMC) of patients with ankylosing spondylitis (AS) and its correlation with inflammatory factors to explore the clinical significance. In total 45 patients with AS were selected at the Weifang People's Hospital from June, 2014 to January, 2016. At the same time, 30 healthy volunteers were also selected to serve as control group. Expression level of miR-146a in PBMC cells of patients in each group was detected by quantitative real-time-polymerase chain reaction (qRT-PCR). Levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in serum and the supernatant of culture medium of PBMC derived from each group were detected by enzyme-linked immunosorbent assay (ELISA). Correlations between expression level of miR-146a and serum inflammatory factors, and clinical indicators were analyzed. Clinical indicators included bath ankylosing spondylitis disease activity index (BASDAI), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and duration of morning stiffness. Expression level of miR-146a in PBMC of AS patients was significantly higher than that of healthy control (P<0.01); levels of TNF-α, IL-1β and IL-6 in serum and the supernatant of culture medium of PBMC derived from AS patients were significant compared to those of control group (P<0.01); expression of miR-146a in PBMC of patients with AS was positively correlated with the levels of TNF-α, IL-1β and IL-6 in serum (r=0.632, P<0.01; r=0.574, P<0.01; r=0.483, P<0.01). In addition, expression level of miR-146a in PBMC of patients with AS was positively correlated with BASDAI, ESR, CRP and duration of morning stiffness (r=0.551, P<0.01; r=0.738, P<0.01; r=0.685, P<0.01; r=0.497, P<0.01). Expression level of miR-146a in PBMC of AS patients was significantly increased and the expression level was positively correlated with the levels of TNF-α, IL-1β and IL-6 in serum (P<0.05). In addition, expression level of miR-146a in PBMC of AS patients was also positively correlated with BASDAI, ESR, CRP and duration of morning stiffness. Those results suggest that miR-146a may be involved in the pathogenesis of AS, and the expression level of miR-146a in PBMC cells may be helpful for diagnosis of AS and judgment of disease activity.

Transcriptome-wide analysis of microRNAs in Branchiostoma belcheri upon Vibrio parahemolyticus infection

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that participate in diverse biological processes via regulating expressions of target genes at post-transcriptional level. Amphioxus, as modern survivor of an ancient chordate lineage, is a model organism for comparative genomics study. However, miRNAs involved in regulating immune responses in Branchiostoma belcheri are largely unclear. Here, we systematically investigated the microRNAs (miRNAs) involved in regulating immune responses in the cephalochordate amphioxus (Branchiostoma belcheri) through next-generation deep sequencing of amphioxus samples infected with Vibrio parahemolyticus. We identified 198 novel amphioxus miRNAs, consisting of 12 conserved miRNAs, 33 candidate star miRNAs and 153 potential amphioxus-specific-miRNAs. Using microarray profiling, 14 miRNAs were differentially expressed post infection, suggesting they are immune-related miRNAs. Eight miRNAs (bbe-miR-92a-3p, bbe-miR-92c-3p, bbe-miR-210-5p, bbe-miR-22-3p, bbe-miR-1∼bbe-miR-133 and bbe-miR-217∼bbe-miR-216 clusters) were significantly increased at 12 h post-infection, while bbe-miR-2072-5p was downregulated at 6 h and 12 h. Three miRNAs, bbe-miR-1-3p, bbe-miR-22-3p and bbe-miR-92a-3p, were confirmed to be involved in immune responses to infection by qRT-PCR. Our findings further clarify important regulatory roles of miRNAs in the innate immune response to bacterial infection in amphioxus.

LPS‑induced downregulation of microRNA‑204/211 upregulates and stabilizes Angiopoietin‑1 mRNA in EA.hy926 endothelial cells

Angiopoietin-1 (ANG-1), a ligand of the endothelial cell-specific TIE2 surface receptor, acts in a complementary and coordinated manner with vascular endothelial growth factor during the process of angiogenesis. ANG-1 can be used as a clinically informative biomarker of disease severity and outcome in severe sepsis. The epithelium-specific Ets transcription factor 1 can activate ANG-1 transcription in the setting of inflammation; however, relatively little is known about the regulation of ANG-1 by microRNAs (miRs). It was observed that lipopolysaccharide (LPS) significantly increased ANG-1 mRNA and protein expression in EA.hy926 cells. ANG-1 was identified as a potential target gene of miR-204 and miR-211. Overexpression of miR-204/211 partially reversed the LPS-induced ANG-1 expression in EA.hy926 cells. Furthermore, overexpression of miR-204/211 significantly reduced the activity of a luciferase reporter gene containing the wild-type ANG-1 3′-untranslated region (UTR), but did not influence the activity of a luciferase reporter gene containing the ANG-1 3′-UTR with a mutated miR-204/211 binding site, confirming that miR-204/211 can bind to the ANG-1 3′-UTR and post-transcriptionally regulate ANG-1. Additionally, LPS enhanced the stability of ANG-1 mRNA by reducing the abundance of miR-204/211. Overexpression of miR-204/211 reduced the migration of EA.hy926 cells in vitro. The present study demonstrated that ANG-1 is a novel direct target gene of miR-204 and miR-211; in addition, LPS was able to inhibit this effect by reducing the expression of miR-204 and miR-211.

MicroRNA Signature of Human Microvascular Endothelium Infected with Rickettsia rickettsii

MicroRNAs (miRNAs) mediate gene silencing by destabilization and/or translational repression of target mRNA. Infection of human microvascular endothelial cells as primary targets of Rickettsiarickettsii, the etiologic agent of Rocky Mountain spotted fever, triggers host responses appertaining to alterations in cellular gene expression. Microarray-based profiling of endothelial cells infected with R.rickettsii for 3 or 24 h revealed differential expression of 33 miRNAs, of which miRNAs129-5p, 200a-3p, 297, 200b-3p, and 595 were identified as the top five up-regulated miRNAs (5 to 20-fold, p ≤ 0.01) and miRNAs 301b-3p, 548a-3p, and 377-3p were down-regulated (2 to 3-fold, p ≤ 0.01). Changes in the expression of selected miRNAs were confirmed by q-RT-PCR in both in vitro and in vivo models of infection. As potential targets, expression of genes encoding NOTCH1, SMAD2, SMAD3, RIN2, SOD1, and SOD2 was either positively or negatively regulated. Using a miRNA-specific mimic or inhibitor, NOTCH1 was determined to be a target of miRNA 200a-3p in R. rickettsii-infected human dermal microvascular endothelial cells (HMECs). Predictive interactome mapping suggested the potential for miRNA-mediated modulation of regulatory gene networks underlying important host cell signaling pathways. This first demonstration of altered endothelial miRNA expression provides new insights into regulatory elements governing mechanisms of host responses and pathogenesis during human rickettsial infections.

Modulation of miR-146a/complement factor H-mediated inflammatory responses in a rat model of temporal lobe epilepsy

Increasing evidence supports the involvement of inflammatory and immune processes in temporal lobe epilepsy (TLE). miRNAs represent small regulatory RNA molecules that have been shown to act as negative regulators of gene expression controlling different biological processes, including immune system homoeostasis and function. We investigated the expression and cellular distribution of miRNA-146a (miR-146a) in a rat model of TLE. Prominent up-regulation of miR-146a activation was evident in 1 week after status epilepticus (SE) and persisted in the chronic phase. The predicted miR-146a's target complement factor H (CFH) mRNA and protein expression was also down-regulated in TLE rat model. Furthermore, transfection of miR-146a mimics in neuronal and glial cells down-regulated CFH mRNA and protein levels respectively. Luciferase reporter assays demonstrated that miR-146a down-regulated CFH mRNA expression via 3'-UTR pairing. Down-regulating miR-146a by intracerebroventricular injection of antagomir-146a enhanced the hippocampal expression of CFH in TLE model and decreased seizure susceptibility. These findings suggest that immunopathological deficits associated with TLE can in part be explained by a generalized miR-146a-mediated down-regulation of CFH that may contribute to epileptogenesis in a rat model of TLE.

IRAK1, a Target of miR-146b, Reduces Cell Aggressiveness of Human Papillary Thyroid Carcinoma

CONTEXT

MicroRNA (miR)-146b is overexpressed in papillary thyroid carcinoma (PTC) and is associated with extrathyroidal invasion, advanced tumor stage, and poor prognosis. However, the underlying mechanism of miR-146b in relation to its oncogenic behavior in PTC and its putative targets remain unknown.

OBJECTIVE

The purpose was to investigate IL-1 receptor-associated kinase 1 (IRAK1) as the potential miR-146b target gene and its involvement in PTC.

DESIGN

We used genome-wide microarray, computational analysis, and 3' UTR reporter gene assays to identify IRAK1 as a miR-146b target gene. In vitro gain/loss-of-function experiments were further performed to determine the effects of IRAK1 on proliferation, colony formation, and wound-healing in PTC cancer cell lines. Expression levels of miR-146b and IRAK1 of 50 cases of PTC and its adjacent normal thyroid specimens were assessed via qRT-PCR.

RESULTS

Microarray expression profile revealed that the mRNA level of IRAK1 gene was down-regulated by miR-146b. The 3' UTR of IRAK1 mRNA was found to be a molecular target of miR-146b posttranscriptional repression in BCPAP cells by reporter gene assays. MiR-146b promoted the migration and proliferation of PTC cells by down-regulating IRAK1 expression, whereas restoration of IRAK1 expression reversed this effect. In addition, the expression of IRAK1 mRNA was significantly lower in PTC clinical tissue samples than normal adjacent thyroid specimens and showed a strong inverse correlation with the expression of miR-146b in PTC specimens.

CONCLUSION

Our results demonstrated that IRAK1 is a direct target of miR-146b and has functional roles to inhibit various aggressive PTC cell activities. In conjunction with current therapeutic regimens, targeting the miR-146b-IRAK1 axis may provide a potential approach for PTC management.

High-efficiency Generation of Multiple Short Noncoding RNA in B-cells and B-cell-derived Extracellular Vesicles

Short noncoding (snc)RNAs are important new players in the landscape of biologics with therapeutic potential. Recently, we reported on a new method for the synthesis and delivery of snc RNA in B-cells transfected with plasmid DNA. Here using the same approach, we demonstrate that B-cells can be programmed for the enforced biogenesis and synchronous release of multiple sncRNAs. Our data show that this goal is feasible and that multiple sncRNA are released in the extracellular compartment in amounts comparable to those from B-cells programmed to express and secrete one scnRNA only. Furthermore, we found that the cargo of extracellular vescicles (EVs) isolated from programmed B-cells is remarkably enriched for multiple sncRNA. On average, we found that the content of multiple sncRNAs in EVs is 3.6 copynumber/EV. Collectively, we demonstrate that B-cells can be easily programmed toward the synthesis and release of multiple sncRNAs, including sncRNA-laden EVs, efficiently and specifically.

Comparison of Total RNA Isolation Methods for Analysis of Immune-Related microRNAs in Market Milks

Bovine milk provides essential nutrients, including immunologically important molecules, as the primary source of nutrition to newborns. Recent studies showed that RNAs from bovine milk contain immune-related microRNAs (miRNA) that regulate various immune systems. To evaluate the biological and immunological activity of miRNAs from milk products, isolation methods need to be established. Six methods for extracting total RNAs from bovine colostrums were adopted to evaluate the isolating efficiency and expression of miRNAs. Total RNA from milk was presented in formulation of small RNAs, rather than ribosomal RNAs. Column-combined phenol isolating methods showed high recovery of total RNAs, especially the commercial columns for biofluid samples, which demonstrated outstanding efficiency for recovering miRNAs. We also evaluated the quantity of five immune-related miRNAs (miR-93, miR-106a, miR-155, miR-181a, miR-451) in milk processed by temperature treatments including low temperature for long time (LTLT, 63℃ for 30 min)-, high temperature for short time (HTST, 75℃ for 15 s)-, and ultra heat treatment (UHT, 120-130℃ for 0.5-4 s). All targeted miRNAs had significantly reduced levels in processed milks compared to colostrum and raw mature milk. Interestingly, the amount of immune-related miRNAs from HTST milk was more resistant than those of LTLT and UHT milks. Our present study examined defined methods of RNA isolation and quantification of immune-specific miRNAs from small volumes of milk for use in further analysis.

MicroRNA-181b stimulates inflammation via the nuclear factor-κB signaling pathway in vitro

Acute lung injury (ALI) is characterized by severe lung edema and an increase in the inflammatory reaction. Considerable evidence has indicated that microRNAs (miRNAs or miRs) are involved in various human diseases; however, the expression profile and function of miRNAs in ALI have been rarely reported. The present study used miRNA microarray and reverse transcription-quantitative polymerase chain reaction to demonstrate that miR-181b is the one of the most significantly upregulated miRNA after lipopolysaccharide (LPS) stimulation in human bronchial epithelial cells, BEAS-2B. To elaborate the role of miR-181b in ALI, an assay was performed to investigate the overexpression of miR-181b in BEAS-2B cells, and the expression of inflammatory factors was then analyzed. The overexpression of miR-181b resulted in the induction of an increment in interleukin (IL)-6 levels. p65 was identified to be a primary component of NF-κB, since it was upregulated in the miR-181b overexpression in the BEAS-2B cells, while pyrrolidine dithiocarbamate, a specific inhibitor of NF-κB, was found to be able to abrogate the upregulation of the expression of p65. In conclusion, the findings of the present study suggested that miR-181b may be involved in the process of LPS-induced inflammation in BEAS-2B cells by activating the NF-κB signaling pathway, which implies that it may serve as a potential therapeutic target for ALI.

MicroRNA regulation of viral immunity, latency, and carcinogenesis of selected tumor viruses and HIV

MicroRNAs (miRNAs) function as key regulators in immune responses and cancer development. In the contexts of infection with oncogenic viruses, miRNAs are engaged in viral persistence, latency establishment and maintenance, and oncogenesis. In this review, we summarize the potential roles and mechanisms of viral and cellular miRNAs in the host-pathogen interactions during infection with selected tumor viruses and HIV, which include (i) repressing viral replication and facilitating latency establishment by targeting viral transcripts, (ii) evading innate and adaptive immune responses via toll-like receptors, RIG-I-like receptors, T-cell receptor, and B-cell receptor pathways by targeting signaling molecules such as TRAF6, IRAK1, IKKε, and MyD88, as well as downstream targets including regulatory cytokines such as tumor necrosis factor α, interferon γ, interleukin 10, and transforming growth factor β, (iii) antagonizing intrinsic and extrinsic apoptosis pathways by targeting pro-apoptotic or anti-apoptotic gene transcripts such as the Bcl-2 family and caspase-3, (iv) modulating cell proliferation and survival through regulation of the Wnt, PI3K/Akt, Erk/MAPK, and Jak/STAT signaling pathways, as well as the signaling pathways triggered by viral oncoproteins such as Epstein-Barr Virus LMP1, by targeting Wnt-inhibiting factor 1, SHIP, pTEN, and SOCSs, and (v) regulating cell cycle progression by targeting cell cycle inhibitors such as p21/WAF1 and p27/KIP1. Further elucidation of the interaction between miRNAs and these key biological events will facilitate our understanding of the pathogenesis of viral latency and oncogenesis and may lead to the identification of miRNAs as novel targets for developing new therapeutic or preventive interventions.

Cross talk of the first-line defense TLRs with PI3K/Akt pathway, in preconditioning therapeutic approach

Toll-like receptor family (TLRs), pattern recognition receptors, is expressed not only on immune cells but also on non-immune cells, including cardiomyocytes, fibroblasts, and vascular endothelial cells. One main function of TLRs in the non-immune system is to regulate apoptosis. TLRs are the central mediators in hepatic, pulmonary, brain, and renal ischemic/reperfusion (I/R) injury. Up-regulation of TLRs and their ligation by either exogenous or endogenous danger signals plays critical roles in ischemia/reperfusion-induced tissue damage. Conventional TLR-NF-κB pathways are markedly activated in failing and ischemic myocardium. Recent studies have identified a cross talk between TLR activation and the PI3K/Akt pathway. The activation of TLRs is proposed to be the most potent preconditioning method after ischemia, to improve the cell survival via the mechanism involved the PI3K/Akt signaling pathway and to attenuate the subsequent TLR-NF-κB pathway stimulation. Thus, TLRs could be a great target in the new treatment approaches for myocardial I/R injury.

Cross talk of the first-line defense TLRs with PI3K/Akt pathway, in preconditioning therapeutic approach

Toll-like receptor family (TLRs), pattern recognition receptors, is expressed not only on immune cells but also on non-immune cells, including cardiomyocytes, fibroblasts, and vascular endothelial cells. One main function of TLRs in the non-immune system is to regulate apoptosis. TLRs are the central mediators in hepatic, pulmonary, brain, and renal ischemic/reperfusion (I/R) injury. Up-regulation of TLRs and their ligation by either exogenous or endogenous danger signals plays critical roles in ischemia/reperfusion-induced tissue damage. Conventional TLR-NF-κB pathways are markedly activated in failing and ischemic myocardium. Recent studies have identified a cross talk between TLR activation and the PI3K/Akt pathway. The activation of TLRs is proposed to be the most potent preconditioning method after ischemia, to improve the cell survival via the mechanism involved the PI3K/Akt signaling pathway and to attenuate the subsequent TLR-NF-κB pathway stimulation. Thus, TLRs could be a great target in the new treatment approaches for myocardial I/R injury.

Circulating microRNAs as biomarkers for inflammatory diseases

MicroRNAs (miRNAs), a class of small, non-coding RNA molecules with gene regulatory functions, have emerged to play a critical role in the pathogenesis of a variety of diseases. Current technological advances allow accurate, high throughput profiling of miRNA abundance in different tissues. More recently, extracellular, circulating miRNAs have begun to be demonstrated as highly stable, blood-based biomarkers for diseases. Understanding the interactions between circulating miRNAs and clinical phenotypes can enhance our knowledge of complex diseases and traits. On the other hand, given the advantages of utilizing blood-based biomarkers (e.g., convenience in collecting samples), circulating miRNAs as biomarkers may improve both disease diagnosis and management. Particularly, we reviewed recent progress in identifying circulating miRNAs as biomarkers for several common inflammatory diseases including asthma, inflammatory bowel disease, and rheumatoid arthritis. Current studies showed a promising future of using circulating miRNAs in the care of inflammatory diseases.

Natural indoles, indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM), attenuate staphylococcal enterotoxin B-mediated liver injury by downregulating miR-31 expression and promoting caspase-2-mediated apoptosis

Staphylococcal enterotoxin B (SEB) is a potent superantigen capable of inducing inflammation characterized by robust immune cell activation and proinflammatory cytokine release. Exposure to SEB can result in food poisoning as well as fatal conditions such as toxic shock syndrome. In the current study, we investigated the effect of natural indoles including indole-3-carbinol (I3C) and 3,3’-diindolylmethane (DIM) on SEB-mediated liver injury. Injection of SEB into D-galactosamine-sensitized female C57BL/6 mice resulted in liver injury as indicated by an increase in enzyme aspartate transaminase (AST) levels, induction of inflammatory cytokines, and massive infiltration of immune cells into the liver. Administration of I3C and DIM (40mg/kg), by intraperitonal injection, attenuated SEB-induced acute liver injury, as evidenced by decrease in AST levels, inflammatory cytokines and cellular infiltration in the liver. I3C and DIM triggered apoptosis in SEB-activated T cells primarily through activation of the intrinsic mitochondrial pathway. In addition, inhibitor studies involving caspases revealed that I3C and DIM-mediated apoptosis in these activated cells was dependent on caspase-2 but independent of caspase-8, 9 and 3. In addition, I3C and DIM caused a decrease in Bcl-2 expression. Both compounds also down-regulated miR-31, which directly targets caspase-2 and influences apoptosis in SEB-activated cells. Our data demonstrate for the first time that indoles can effectively suppress acute hepatic inflammation caused by SEB and that this may be mediated by decreased expression of miR-31 and consequent caspase-2-dependent apoptosis in T cells.

miRNAs in urine: a mirror image of kidney disease?

miRNAs are short non-coding RNAs that control post-transcriptional regulation of gene expression. They are found ubiquitously in tissue and body fluids and participate in the pathogenesis of many diseases. Due to these characteristics and their stability, miRNAs could serve as biomarkers of different pathologies of the kidney. Urine is a non-invasive reservoir of molecules, especially indicative of the urinary system. In this review, we focus on urinary miRNAs and their potential to serve as biomarkers in kidney disease. Past studies show that urinary miRNAs correlate with renal dysfunctions and with processes involved in the pathophysiology. However, these studies also stress the need for future research focusing on large-scale studies to confirm the usability of urinary miRNAs as diagnostic and/or prognostic markers of different kidney diseases in clinical practice.

microRNAs as regulators of adipogenic differentiation of mesenchymal stem cells

microRNAs (miRNAs) constitute complex regulatory network, fine tuning the expression of a myriad of genes involved in different biological and physiological processes, including stem cell differentiation. Mesenchymal stem cells (MSCs) are multipotent stem cells present in the bone marrow stroma, and the stroma of many other tissues, and can give rise to a number of mesoderm-type cells including adipocytes and osteoblasts, which form medullary fat and bone tissues, respectively. The role of bone marrow fat in bone mass homeostasis is an area of intensive investigation with the aim of developing novel approaches for enhancing osteoblastic bone formation through inhibition of bone marrow fat formation. A number of recent studies have reported several miRNAs that enhance or inhibit adipogenic differentiation of MSCs and with potential use in microRNA-based therapy to regulate adipogenesis in the context of treating bone diseases and metabolic disorders. The current review focuses on miRNAs and their role in regulating adipogenic differentiation of MSCs.

microRNA-320/RUNX2 axis regulates adipocytic differentiation of human mesenchymal (skeletal) stem cells

The molecular mechanisms promoting lineage-specific commitment of human mesenchymal (skeletal or stromal) stem cells (hMSCs) into adipocytes (ADs) are not fully understood. Thus, we performed global microRNA (miRNA) and gene expression profiling during adipocytic differentiation of hMSC, and utilized bioinformatics as well as functional and biochemical assays, and identified several novel miRNAs differentially expressed during adipogenesis. Among these, miR-320 family (miR-320a, 320b, 320c, 320d and 320e) were ~2.2–3.0-fold upregulated. Overexpression of miR-320c in hMSC enhanced adipocytic differentiation and accelerated formation of mature ADs in ex vivo cultures. Integrated analysis of bioinformatics and global gene expression profiling in miR-320c overexpressing cells and during adipocytic differentiation of hMSC identified several biologically relevant gene targets for miR-320c including RUNX2, MIB1 (mindbomb E3 ubiquitin protein ligase 1), PAX6 (paired box 6), YWHAH and ZWILCH. siRNA-mediated silencing of those genes enhanced adipocytic differentiation of hMSC, thus corroborating an important role for those genes in miR-320c-mediated adipogenesis. Concordant with that, lentiviral-mediated stable expression of miR-320c at physiological levels (~1.5-fold) promoted adipocytic and suppressed osteogenic differentiation of hMSC. Luciferase assay validated RUNX2 (Runt-related transcription factor 2) as a bona fide target for miR-320 family. Therefore, our data suggest miR-320 family as possible molecular switch promoting adipocytic differentiation of hMSC. Targeting miR-320 may have therapeutic potential in vivo through regulation of bone marrow adipogenesis.

First trimester PBMC microRNA predicts adverse pregnancy outcome

PROBLEM

Prior to the end of the first trimester, pathogenic mechanisms may commit pregnancies to adverse outcome such as pre-eclampsia and miscarriage. A long-term search for biomarkers predicting these adverse outcomes has not identified any that reliably succeed prior to the beginning of the second trimester. MicroRNAs, with their important role as regulators of signaling and metabolic pathways within living cells, may offer a new approach.

METHODS

Optimal maternal PBMC microRNA markers were investigated using a series of sequential experiments, and 30 microRNAs were selected based on these results. Quantitative RT-PCR was then performed on these 30 microRNAs for 39 patients [19 healthy deliveries, 12 pre-eclampsia (seven late onset and five early onset) and eight miscarriages] during the first trimester of pregnancy. Results were scored, and their predictive values assessed.

RESULTS

MicroRNA quantification in the early first trimester (mean 34.9 ± 19.2 days post-implantation) predicted miscarriage and late pre-eclampsia with a P value of P < 0.0001 and achieved an AUC of 0.90 for miscarriage and 0.90 for late pre-eclampsia.

CONCLUSION

MicroRNA quantification of maternal blood cells offers the clinician a single test result that is simple to interpret and available much earlier in pregnancy than previously obtainable. In addition, it is the only early pregnancy marker, to date, that can successfully predict late pre-eclampsia. Although the studies that we report are preliminary, we hope that future research will build upon our discoveries and enhance the power of maternal cell microRNA to predict adverse pregnancy outcome in the clinic.

Recent insights into hepatitis B virus-host interactions

Hepatitis B virus (HBV) poses a threat to global public health mainly because of complications of HBV-related chronic liver disease. HBV exhibits a narrow host range, replicating primarily in hepatocytes by a still poorly understood mechanism. For the generation of progeny virions, HBV depends on interactions with specific host factors through its life cycle. Revealing and characterizing these interactions are keys to identifying novel antiviral targets, and to developing specific treatment strategies for HBV patients. In this review, recent insights into the HBV-host interactions, especially on virus entry, intracellular trafficking, genome transcription and replication, budding and release, and even cellular restriction factors were reviewed.

Transcriptomic analysis reveals key regulators of mammogenesis and the pregnancy-lactation cycle

An organ unique to mammals, the mammary gland develops 90% of its mass after birth and experiences the pregnancylactation-involution cycle (PL cycle) during reproduction. To understand mammogenesis at the transcriptomic level and using a ribo-minus RNA-seq protocol, we acquired greater than 50 million reads each for the mouse mammary gland during pregnancy (day 12 of pregnancy), lactation (day 14 of lactation), and involution (day 7 of involution). The pregnancy-, lactation- and involution-related sequencing reads were assembled into 17344, 10160, and 13739 protein-coding transcripts and 1803, 828, and 1288 non-coding RNAs (ncRNAs), respectively. Differentially expressed genes (DEGs) were defined in the three samples, which comprised 4843 DEGs (749 up-regulated and 4094 down-regulated) from pregnancy to lactation and 4926 DEGs (4706 up-regulated and 220 down-regulated) from lactation to involution. Besides the obvious and substantive up- and down-regulation of the DEGs, we observe that lysosomal enzymes were highly expressed and that their expression coincided with milk secretion. Further analysis of transcription factors such as Trps1, Gtf2i, Tcf7l2, Nupr1, Vdr, Rb1, and Aebp1, and ncRNAs such as mir-125b, Let7, mir-146a, and mir-15 has enabled us to identify key regulators in mammary gland development and the PL cycle.

Circulating levels of miR-146a and IL-17 are significantly correlated with the clinical activity of Graves' ophthalmopathy

Graves' ophthalmopathy (GO) is a common autoimmune disease that is difficult to deal with due to limited clinical evaluation methods. Recently miR-146a and Interleukin-17 (IL-17) have been found to be involved in autoimmune disorders and correlated with disease activity. However, it is unclear whether they are involved in Graves' ophthalmopathy (GO). The aim of this study is to investigate the correlation of circulating levels of miR-146a and IL-17 with clinical activity in GO patients. Fifty-seven study subjects were enrolled in four groups according to the corresponding criteria: active-GO, inactive-GO, Graves disease (GD) without ophthalmopathy, and healthy control group. The circulating levels of miR-146a and IL-17 were determined by qRT-PCR and ELISA, respectively. Serum IL-17 levels of GD, inactive-GO, and active-GO groups were all significantly higher than that of control (all P < 0.001). Active-GO group had significantly higher IL-17 level than inactive-GO and GD groups (P = 0.024 and P = 0.001, respectively). Active-GO and inactive-GO group had significantly lower miR-146a expressions than control (P < 0.05). Active-GO group had significantly lower miR-146a than inactive-GO group (P < 0.05). Serum levels of IL-17 and miR-146a were both significantly correlated with clinical activity score (CAS) in GO patients (P < 0.001, P < 0.001, respectively). There was a significant negative correlation of circulating miR-146a expression with serum IL-17 levels (P < 0.01). These findings indicated that circulating levels of miR-146a and IL-17 may be potential biomarkers of active GO, and may play a key role in the progression of GO.

Overexpressed miRNA-155 dysregulates intestinal epithelial apical junctional complex in severe acute pancreatitis

AIM: To investigate whether miRNA-155 (miR-155) dysregulates apical junctional complex (AJC) protein expression in experimental severe acute pancreatitis (SAP).

METHODS: Twenty-four male BALB/c mice were randomly assigned to two groups: the SAP group (n = 12) receiving sequential intraperitoneal injection of 50 µg/kg caerulein and 10 mg/kg lipopolysaccharide over 6 h, and the control group (n = 12) receiving intraperitoneal injection of normal saline. Animals were sacrificed 3 h following the last injection for collection of blood samples and pancreas and distal ileal segment specimens. Routine pancreas and intestine histology was used to assess SAP pathology and intestinal epithelial barrier damage. Levels of serum amylase, diamine oxidase (DAO), and tumor necrosis factor (TNF)-α were determined using commercial kits. Total RNA samples were isolated from intestinal epithelial specimens and reversely transcribed into cDNA. miR-155 and RhoA mRNA expression profiles were determined using quantitative real-time polymerase chain reaction. Target genes for miR-155 were predicted using the miRTarBase database, RNA22 and PicTar computational methods. Western blotting was performed to quantitate the protein expression levels of the target gene RhoA, as well as zonula occludens (ZO)-1 and E-cadherin, two AJC component proteins.

RESULTS: Intraperitoneal injection of caerulein and lipopolysaccharide successfully induced experimental acute pancreatic damage (SAP vs control, 10.0 ± 2.0 vs 3.2 ± 1.2, P < 0.01) and intestinal epithelial barrier damage (3.2 ± 0.7 vs 1.4 ± 0.7, P < 0.01). Levels of serum amylase (21.6 ± 5.1 U/mL vs 14.3 ± 4.2 U/mL, P < 0.01), DAO (21.4 ± 4.1 mg/mL vs 2.6 ± 0.8 mg/mL, P < 0.01), and TNF-α (61.0 ± 15.1 ng/mL vs 42.9 ± 13.9 ng/mL, P < 0.01) increased significantly in SAP mice compared to those in control mice. miR-155 was significantly overexpressed in SAP intestinal epithelia (1.94 ± 0.50 fold vs 1.03 ± 0.23 fold, P < 0.01), and RhoA gene containing three miR-155-specific binding sites in the three prime untranslated regions was one of the target genes for miR-155. RhoA (22.7 ± 5.8 folds vs 59.6 ± 11.6 folds, P < 0.01), ZO-1 (46 ± 18 folds vs 68 ± 19 folds, P < 0.01), and E-cadherin proteins (48 ± 15 folds vs 77 ± 18 folds, P < 0.01) were underexpressed in SAP intestinal epithelia although RhoA mRNA expression was not significantly changed in SAP (0.97 ± 0.18 folds vs 1.01 ± 0.17 folds, P > 0.05).

CONCLUSION: TNF-α-regulated miR-155 overexpression inhibits AJC component protein syntheses of ZO-1, and E-cadherin by downregulating post-transcriptional RhoA expression, and disrupts intestinal epithelial barrier in experimental SAP.

Identification and characterization of novel and differentially expressed microRNAs in peripheral blood from healthy and mastitis Holstein cattle by deep sequencing

MicroRNA (miRNA) mediates post-transcriptional gene regulation and plays an important role in regulating the development of immune cells and in modulating innate and adaptive immune responses in mammals, including cattle. In the present study, we identified novel and differentially expressed miRNAs in peripheral blood from healthy and mastitis Holstein cattle by Solexa sequencing and bioinformatics. In total, 608 precursor hairpins (pre-miRNAs) encoding for 753 mature miRNAs were detected. Statistically, 173 unique miRNAs (of 753, 22.98%) were identified that had significant differential expression between healthy and mastitis Holstein cattle (P < 0.001). Most differentially expressed miRNAs (118 of 173, 68.21%) belonged to the chemokine signaling pathway involved in the immune responses. This study expands the number of miRNAs known to be expressed in cattle. The patterns of miRNAs expression differed significantly between the peripheral blood from healthy and mastitis Holstein cattle, which provide important information on mastitis in miRNAs expression. Diverse miRNAs may play an important role in the treatment of mastitis in Holstein cattle.

Synthesis and delivery of short, noncoding RNA by B lymphocytes

Evolutionarily conserved short (20-30 nucleotides) noncoding RNAs (microRNAs) are powerful regulators of gene expression in a variety of physiological and pathological processes. As such, means to efficiently modulate microRNA function constitute an important therapeutic opportunity. Here we demonstrate that primary B lymphocytes can be genetically programmed with nonviral plasmid DNA for the biogenesis and delivery of antisense sequences (anti-microRNA) against microRNA-150 (miR-150). Within 18 h of transfection with an anti-miR-150 construct, primary B lymphocytes secrete ∼3,000 copies of anti-miR-150 molecules per cell. Anti-miR-150 molecules released by B lymphocytes were internalized by CD8 T lymphocytes during cross-priming in vitro and in vivo, resulting in marked down-regulation of endogenous miR-150. However, such internalization was not observed in the absence of cross-priming. These results suggest that shuttling anti-miR-150 molecules from B lymphocytes to T cells requires the activation of receiver T cells via the antigen receptor. Finally, anti-miR-150 synthesized in B cells were secreted both as free and extracellular vesicle-associated fractions, but only extracellular vesicle-associated anti-miR-150 were apparently taken up by CD8 T cells. Collectively, these data indicate that primary B lymphocytes represent an efficient platform for the synthesis and delivery of short, noncoding RNA, paving the way for an approach to immunogenomic therapies.

Identification of miRNAs and miRNA-mediated regulatory pathways in Carica papaya

Plant microRNAs (miRNAs) post-transcriptionally regulate target gene expression to modulate growth and development and biotic and abiotic stress responses. By analyzing small RNA deep sequencing data in combination with the genome sequence, we identified 75 conserved miRNAs and 11 novel miRNAs. Their target genes were also predicted. For most conserved miRNAs, the miRNA-target pairs were conserved across plant species. In addition to these conserved miRNA-target pairs, we also identified some papaya-specific miRNA-target regulatory pathways. Both miR168 and miR530 target the Argonaute 1 gene, indicating a second autoregulatory mechanism for miRNA regulation. A non-conserved miRNA was mapped within an intron of Dicer-like 1 (DCL1), suggesting a conserved homeostatic autoregulatory mechanism for DCL1 expression. A 21-nt miRNA triggers secondary siRNA production from its target genes, nucleotide-binding site leucine-rich repeat protein genes. Certain phased-miRNAs were processed from their conserved miRNA precursors, indicating a putative miRNA evolution mechanism. In addition, we identified a Carica papaya-specific miRNA that targets an ethylene receptor gene, implying its function in the ethylene signaling pathway. This work will also advance our understanding of miRNA functions and evolution in plants.

Differential gene expression in thrombomodulin (TM; CD141)(+) and TM(-) dendritic cell subsets

Previously we have shown in a mouse model of bronchial asthma that thrombomodulin can convert immunogenic conventional dendritic cells into tolerogenic dendritic cells while inducing its own expression on their cell surface. Thrombomodulin⁺ dendritic cells are tolerogenic while thrombomodulin⁻ dendritic cells are pro-inflammatory and immunogenic. Here we hypothesized that thrombomodulin treatment of dendritic cells would modulate inflammatory gene expression. Murine bone marrow-derived dendritic cells were treated with soluble thrombomodulin and expression of surface markers was determined. Treatment with thrombomodulin reduces the expression of maturation markers and increases the expression of TM on the DC surface. Thrombomodulin treated and control dendritic cells were sorted into thrombomodulin⁺ and thrombomodulin⁻ dendritic cells before their mRNA was analyzed by microarray. mRNAs encoding pro-inflammatory genes and dendritic cells maturation markers were reduced while expression of cell cycle genes were increased in thrombomodulin-treated and thrombomodulin⁺ dendritic cells compared to control dendritic cells and thrombomodulin⁻ dendritic cells. Thrombomodulin-treated and thrombomodulin⁺ dendritic cells had higher expression of 15-lipoxygenase suggesting increased synthesis of lipoxins. Thrombomodulin⁺ dendritic cells produced more lipoxins than thrombomodulin⁻ dendritic cells, as measured by ELISA, confirming that this pathway was upregulated. There was more phosphorylation of several cell cycle kinases in thrombomodulin⁺ dendritic cells while phosphorylation of kinases involved with pro-inflammatory cytokine signaling was reduced. Cultures of thrombomodulin⁺ dendritic cells contained more cells actively dividing than those of thrombomodulin⁻ dendritic cells. Production of IL-10 is increased in thrombomodulin⁺ dendritic cells. Antagonism of IL-10 with a neutralizing antibody inhibited the effects of thrombomodulin treatment of dendritic cells suggesting a mechanistic role for IL-10. The surface of thrombomodulin⁺ dendritic cells supported activation of protein C and procarboxypeptidase B2 in a thrombomodulin-dependent manner. Thus thrombomodulin treatment increases the number of thrombomodulin⁺ dendritic cells, which have significantly altered gene expression compared to thrombomodulin⁻ dendritic cells in key immune function pathways.