5-lipoxygenase is a direct target of miR-19a-3p and miR-125b-5p

Influence of Maternal Diet and Lactation Time on the Exosomal miRNA Cargo in Breast Milk

The importance of breastfeeding for maternal and infant health is widely accepted. In this sense, the presence of macro and micronutrients in human milk ensures proper and safe infant nutrition, along with multiple bioactive molecules that modulate the newborn's immunity. Usually packaged within exosomes, miRNAs circulating in milk are bioavailable to breastfed infants. Their role in infant development is poorly understood, mainly because the miRNA cargo of human milk has not been fully elucidated to date. The objective of this study is to assess the presence of eleven miRNAs (miR-148a-3p, miR-29b-3p, miR-125b-5p, miR-200c-3p, let-7f-5p, let-7b-5p, let-7a-5p, miR-92a, miR-181a-3p, miR-30a-5p and miR-155-5p) in breast milk exosomes and determine the impact of lactation time and maternal factors on their levels. Samples were collected from a cohort of 59 Spanish mothers, ranging from 1 to 59 months of lactation. MiRNAs were analyzed using reverse transcription and qPCR. Lactation time showed a significant and noteworthy downregulation for miR-148a-3p, miR-200c-3p and miR-125b-5p and hsa-let-7a-5p. The levels of miRNAs were correlated with the levels of some fatty acids such as arachidonic acid and DHA. Also, a positive correlation between Se and arachidonic acid levels in breast milk was found, linked with upregulated miR-125b. The results of this work demonstrate that miRNA levels are dynamic, probably with the aim of adapting to the specific needs of the infant.

The MiR-139-5p and CXCR4 axis may play a role in high glucose-induced inflammation by regulating monocyte migration

MicroRNAs, a class of small non-coding RNA molecules that regulate gene expression post-transcriptionally, are implicated in various pathological conditions including diabetes mellitus (DM). DM has been increasingly recognized as an inflammatory disease and monocytes play a key role in propagating inflammation under hyperglycemic conditions. We hypothesize that high glucose dysregulates microRNAs to promote monocyte inflammatory activity, which may contribute to the pathogenesis of DM. THP-1 monocytes were cultured in normal (5 mM) and high (25 mM) glucose conditions. RT-qPCR and Western blotting were performed to assay microRNAs and proteins, respectively. Monocytes were transfected with microRNA mimics using Lipofectamine RNAiMAX reagent. THP-1 monocyte growth was assessed using Calcein-AM dye and a Boyden chamber assay was applied to measure monocyte migration. The results showed that high glucose downregulated miR-139-5p associated with increased protein expression of CXCR4, an experimentally validated target of miR-139-5p. Correspondingly, treatment with high glucose resulted in a significant increase in THP-1 cell migration towards SDF-1, a cognate ligand for CXCR4. MiR-139-5p overexpression inhibited high glucose-induced CXCR4 expression, leading to reduced cell migration towards SDF-1. High glucose did not affect THP-1 monocyte growth. In conclusion, the miR-139-5p-CXCR4 axis may play a role in high glucose-induced inflammation by regulating monocyte migration.

The role of human 5-Lipoxygenase (5-LO) in carcinogenesis - a question of canonical and non-canonical functions

5-Lipoxygenase (5-LO), a fatty acid oxygenase, is the central enzyme in leukotriene (LT) biosynthesis, potent arachidonic acid-derived lipid mediators released by innate immune cells, that control inflammatory and allergic responses. In addition, through interaction with 12- and 15-lipoxgenases, the enzyme is involved in the formation of omega-3 fatty acid-based oxylipins, which are thought to be involved in the resolution of inflammation. The expression of 5-LO is frequently deregulated in solid and liquid tumors, and there is strong evidence that the enzyme plays an important role in carcinogenesis. However, global inhibition of LT formation and signaling has not yet shown the desired success in clinical trials. Curiously, the release of 5-LO-derived lipid mediators from tumor cells is often low, and the exact mechanism by which 5-LO influences tumor cell function is poorly understood. Recent data now show that in addition to releasing oxylipins, 5-LO can also influence gene expression in a lipid mediator-independent manner. These non-canonical functions, including modulation of miRNA processing and transcription factor shuttling, most likely influence cancer cell function and the tumor microenvironment and might explain the low clinical efficacy of pharmacological strategies that previously only targeted oxylipin formation and signaling by 5-LO. This review summarizes the canonical and non-canonical functions of 5-LO with a particular focus on tumorigenesis, highlights unresolved issues, and suggests future research directions.

Identification of Important Genes Associated with the Development of Atherosclerosis

Atherosclerosis is one of the most important medical problems due to its prevalence and significant contribution to the structure of temporary and permanent disability and mortality. Atherosclerosis is a complex chain of events occurring in the vascular wall over many years. Disorders of lipid metabolism, inflammation, and impaired hemodynamics are important mechanisms of atherogenesis. A growing body of evidence strengthens the understanding of the role of genetic and epigenetic factors in individual predisposition and development of atherosclerosis and its clinical outcomes. In addition, hemodynamic changes, lipid metabolism abnormalities, and inflammation are closely related and have many overlapping links in regulation. A better study of these mechanisms may improve the quality of diagnosis and management of such patients.

Structures of Leukotriene Biosynthetic Enzymes and Development of New Therapeutics

Leukotrienes are potent immune-regulating lipid mediators with patho-genic roles in inflammatory and allergic diseases, particularly asthma. These autacoids also contribute to low-grade inflammation, a hallmark of cardiovascular, neurodegenerative, metabolic, and tumor diseases. Biosynthesis of leukotrienes involves release and oxidative metabolism of arachidonic acid and proceeds via a set of cytosolic and integral membrane enzymes that are typically expressed by cells of the innate immune system. In activated cells, these enzymes traffic and assemble at the endoplasmic and perinuclear membrane, together comprising a biosynthetic complex. Here we describe recent advances in our molecular understanding of the protein components of the leukotriene-synthesizing enzyme machinery and also briefly touch upon the leukotriene receptors. Moreover, we discuss emerging opportunities for pharmacological intervention and development of new therapeutics.

Altered MicroRNA Expression in Intracranial Aneurysmal Tissues: Possible Role in TGF-β Signaling Pathway

The molecular mechanisms behind the rupture of intracranial aneurysms remain obscure. MiRNAs are key regulators of a wide array of biological processes altering protein synthesis by binding to target mRNAs. However, variations in miRNA levels in ruptured aneurysmal wall have not been completely examined. We hypothesized that altered miRNA signature in aneurysmal tissues could potentially provide insight into aneurysm pathophysiology. Using a high-throughput miRNA microarray screening approach, we compared the miRNA expression pattern in aneurysm tissues obtained during surgery from patients with aneurysmal subarachnoid hemorrhage (aSAH) with control tissues (GEO accession number GSE161870). We found that the expression of 70 miRNAs was altered. Expressions of the top 10 miRNA were validated, by qRT-PCR and results were correlated with clinical characteristics of aSAH patients. The level of 10 miRNAs (miR-24-3p, miR-26b-5p, miR-27b-3p, miR-125b-5p, miR-143-3p, miR-145-5p, miR-193a-3p, miR-199a-5p, miR-365a-3p/365b-3p, and miR-497-5p) was significantly decreased in patients compared to controls. Expression of miR-125b-5p, miR-143-3p and miR-199a-5p was significantly decreased in patients with poor prognosis and vasospasm. The target genes of few miRNAs were enriched in Transforming growth factor-beta (TGF-β) and Mitogen-activated protein kinases (MAPK) pathways. We found significant negative correlation between the miRNA and mRNA expression (TGF-β1, TGF-β2, SMAD family member 2 (SMAD2), SMAD family member 4 (SMAD4), MAPK1 and MAPK3) in aneurysm tissues. We suggest that miR-26b, miR-199a, miR-497and miR-365, could target multiple genes in TGF-β and MAPK signaling cascades to influence inflammatory processes, extracellular matrix and vascular smooth muscle cell degradation and apoptosis, and ultimately cause vessel wall degradation and rupture.

Micro-Players of Great Significance-Host microRNA Signature in Viral Infections in Humans and Animals

Over time, more and more is becoming known about micro-players of great significance. This is particularly the case for microRNAs (miRNAs; miR), which have been found to participate in the regulation of many physiological and pathological processes in both humans and animals. One such process is viral infection in humans and animals, in which the host miRNAs—alone or in conjunction with the virus—interact on two levels: viruses may regulate the host’s miRNAs to evade its immune system, while the host miRNAs can play anti- or pro-viral roles. The purpose of this comprehensive review is to present the key miRNAs involved in viral infections in humans and animals. We summarize the data in the available literature, indicating that the signature miRNAs in human viral infections mainly include 12 miRNAs (i.e., miR-155, miR-223, miR-146a, miR-122, miR-125b, miR-132, miR-34a, miR -21, miR-16, miR-181 family, let-7 family, and miR-10a), while 10 miRNAs are commonly found in animals (i.e., miR-155, miR-223, miR-146a, miR-145, miR-21, miR-15a/miR-16 cluster, miR-181 family, let-7 family, and miR-122) in this context. Knowledge of which miRNAs are involved in different viral infections and the biological functions that they play can help in understanding the pathogenesis of viral diseases, facilitating the future development of therapeutic agents for both humans and animals.

Genetic and Epigenetic Regulation of Lipoxygenase Pathways and Reverse Cholesterol Transport in Atherogenesis

Atherosclerosis is one of the most important medical and social problems of modern society. Atherosclerosis causes a large number of hospitalizations, disability, and mortality. A considerable amount of evidence suggests that inflammation is one of the key links in the pathogenesis of atherosclerosis. Inflammation in the vascular wall has extensive cross-linkages with lipid metabolism, and lipid mediators act as a central link in the regulation of inflammation in the vascular wall. Data on the role of genetics and epigenetic factors in the development of atherosclerosis are of great interest. A growing body of evidence is strengthening the understanding of the significance of gene polymorphism, as well as gene expression dysregulation involved in cross-links between lipid metabolism and the innate immune system. A better understanding of the genetic basis and molecular mechanisms of disease pathogenesis is an important step towards solving the problems of its early diagnosis and treatment.

Mycobacterium avium subsp. paratuberculosis exploits miRNA expression to modulate lipid metabolism and macrophage polarisation pathways during infection

Pathogenic mycobacteria including Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease, manipulate host macrophages to persist and cause disease. In mycobacterial infection, highly plastic macrophages, shift between inflammatory M1 and permissive M2 phenotypes which alter the disease outcome and allow bacteria to survive intracellularly. Here we examine the impact of MAP infection on polarised macrophages and how increased lipid availability alters macrophage phenotype and bacterial persistence. Further, we assess if host microRNA (miRNA) are sensitive to macrophage polarisation state and how MAP can drive their expression to overcome innate responses. Using in vitro MAP infection, we find that increasing lipid availability through supplementing culture media with exogenous lipid increases cellular nitric oxide production. Lipid-associated miRs -19a, -129, -24, and -24-3p are differentially expressed following macrophage polarisation and lipid supplementation and are further regulated during MAP infection. Collectively, our results highlight the importance of host lipid metabolism in MAP infection and demonstrate control of miRNA expression by MAP to favour intracellular persistence.

Respiratory Syncytial Virus Nonstructural Protein 1 Promotes 5-Lipoxygenase via miR-19a-3p

Background

Respiratory syncytial virus (RSV) infection can regulate the expression of a wide range of noncoding microRNAs (miRNAs), in which mir-19a-3p can participate in airway inflammatory response by regulating 5-lipoxygenase (5-LO) pathway. RSV nonstructural protein (NS) 1 is involved in the airway hyperresponsiveness during RSV infection.

Methods

The expression levels of miR-19a-3p and inflammatory signaling-related indicators were detected using quantitative real-time PCR and western blot analyses on the A549 cells transfected with NS1 expression plasmids (pNS1). The 5-LO-mediated inflammatory signaling pathway was assessed when the miR-19a-3p or 5-LO was inhibited.

Results

The immunofluorescence analysis showed that the plasmid-mediated NS1 protein was observed in both the cytoplasm and nucleus. The expression level of miR-19a-3p was significantly upregulated in the pNS1 or RSV-treated cells, which was reversed by the NS1 small interfering RNA. In addition, pNS1 also upregulated the expression of 5-LO, interleukin-5 (IL-5), and leukotriene B4 (LTB4), which was also significantly inhibited by the miR-19a-3p antagonists. The 5-LO inhibitor MK886 prevented the increase in the expression level of IL-5 induced by pNS1.

Conclusions

These results suggested that the RSV NS1 might play an important role in the pathogenesis of RSV by activating the 5-LO and subsequent inflammatory cytokines through miR-19a-3p.

An Apple a Day Keeps the Doctor Away: Potential Role of miRNA 146 on Macrophages Treated with Exosomes Derived from Apples

The constant dialogue between the plant world and the animal world (including man among them) has been known since the time of Adam and Eve, where an apple was the origin of the evils of the world. Apart from Snow White—who might have something to object to when it comes to the use of apples—fruits, plants, and natural extracts have been known for millennia as remedies for human health-related ailments. In the light of such evidence, the aim of the present work was to investigate from a biological point of view the potential role of apple exosomes in inflammatory processes on human cells. To this end we isolated and characterized apple exosomes and treated human cells such as macrophages and NCTC L929 as cancer cells in order to evaluate the tumorigenic and anti-inflammatory effect of apple exomes. Microscopic and molecular biology analyses were conducted to characterize exosomes and to assess cell proliferation, death, and miRNA line, as well as gene expression and the uptake of exosomes by cells. The results confirm the absolute biological safety of exosomes and their anti-inflammatory effect, mediated mainly by miRNA146 production by M2 macrophages.

Host microRNAs regulate expression of hepatitis B virus genes during transmission from patients' sperm to embryo

Human sperm nucleus contains diverse RNA populations. This study aimed to screen and identify host microRNAs (miRs) that regulate gene expression of hepatitis B virus (HBV) during transmission from patients' sperm to sperm-derived embryos. Using microarrays, 336 miRs were found to be differentially expressed. After validation using real-time quantitative RT-PCR (RT-qPCR), four miRs were selected as targets. Using RT-qPCR and enzyme-linked immunosorbent assays, when patients' sperm were treated with mimics (or inhibitors) specific for hsa-miR-19a-3p and hsa-miR-29c-3p, the S gene transcription in sperm and translation in sperm-derived embryos was downregulated (or upregulated). There were significant differences in transcriptional and translational levels of the S gene between the test and control groups. These findings suggest that hsa-miR-19a-3p and hsa-miR-29c-3p significantly suppressed expression of the S gene, offering potential therapeutic targets for treating patients with HBV infection, and further reducing the negative impact of HBV infection on sperm fertilizing capacity.

Emerging role of cysteinyl LTs in cancer

Cysteinyl leukotrienes (CysLTs) are inflammatory lipid mediators that play a central role in the pathophysiology of several inflammatory diseases. Recently, there has been an increased interest in determining how these lipid mediators orchestrate tumour development and metastasis through promoting a pro-tumour micro-environment. Up-regulation of CysLTs receptors and CysLTs production is found in a number of cancers and has been associated with increased tumorigenesis. Understanding the molecular mechanisms underlying the role of CysLTs and their receptors in cancer progression will help investigate the potential of targeting CysLTs signalling for anti-cancer therapy. This review gives an overview of the biological effects of CysLTs and their receptors, along with current knowledge of their regulation and expression. It also provides a recent update on the molecular mechanisms that have been postulated to explain their role in tumorigenesis and on the potential of anti-CysLTs in the treatment of cancer.

miRNAs and Leukotrienes in Respiratory Syncytial Virus Infection

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate posttranscription by binding to 3'-untranslated regions of target mRNAs. Recent functional studies have elucidated mechanisms that miRNAs regulate leukotriene synthesis by perturbing arachidonic acid metabolism. Both microarrays and high-throughput sequencing revealed distinct differential expression of miRNAs in children with respiratory syncytial virus (RSV) infection compared with healthy controls. Abnormal miRNA expression may contribute to higher leukotriene levels, which is associated with airway hyperreactivity. Targeting miRNAs may benefit to restore the homeostasis of inflammatory reaction and provide new strategies to alleviate airway hyperreactivity induced by RSV. In this article, we provide an overview of the current knowledge about miRNAs modulating leukotrienes through regulation of arachidonic acid metabolism with a special focus on miRNAs aberrantly expressed in children with RSV infection.

Circulating differential miRNAs profiling and expression in hexavalent chromium exposed electroplating workers

Hexavalent chromium [Cr (Ⅵ)] has extensive applications in industries, and long-term occupational exposure to Cr (Ⅵ) may lead to lung carcinoma and other cancers. While microRNA (miRNA) can take part in carcinogenesis, little is known about its expression profile in the population with Cr (Ⅵ) exposure. Thus, this study aimed to explore miRNA expression profiles in Cr (Ⅵ) exposed workers and to identify the potential biological function of differentially expressed miRNAs. A total of 45 significant differentially expressed miRNAs were identified by the miRNA array. The results of validation showed that miR-19a-3p, miR-19b-3p, and miR-142-3p were downregulated and miR-590-3p and miR-941 were upregulated in the exposure group. Multivariate analysis demonstrated that age, exposure duration and urinary chromium level were associated with one or more miRNAs expression. Target gene analysis indicated that these miRNAs might participate in the regulation of DNA damage-related signaling pathways. Taken together, Cr (Ⅵ) exposure can result in differential expression of miRNAs in occupational workers, and the expression of these miRNAs is correlated with the level and duration of Cr (Ⅵ) exposure, and the differentially expressed miRNAs may participate in DNA damage response.

Modulation of microRNA processing by 5-lipoxygenase

The miRNA biogenesis is tightly regulated to avoid dysfunction and consequent disease development. Here, we describe modulation of miRNA processing as a novel noncanonical function of the 5-lipoxygenase (5-LO) enzyme in monocytic cells. In differentiated Mono Mac 6 (MM6) cells, we found an in situ interaction of 5-LO with Dicer, a key enzyme in miRNA biogenesis. RNA sequencing of small noncoding RNAs revealed a functional impact, knockout of 5-LO altered the expression profile of several miRNAs. Effects of 5-LO could be observed at two levels. qPCR analyses thus indicated that (a) 5-LO promotes the transcription of the evolutionarily conserved miR-99b/let-7e/miR-125a cluster and (b) the 5-LO-Dicer interaction downregulates the processing of pre-let-7e, resulting in an increase in miR-125a and miR-99b levels by 5-LO without concomitant changes in let-7e levels in differentiated MM6 cells. Our observations suggest that 5-LO regulates the miRNA profile by modulating the Dicer-mediated processing of distinct pre-miRNAs. 5-LO inhibits the formation of let-7e which is a well-known inducer of cell differentiation, but promotes the generation of miR-99b and miR-125a known to induce cell proliferation and the maintenance of leukemic stem cell functions.

Analysis of proximal ALOX5 promoter binding proteins by quantitative proteomics

5-Lipoxygenase (5-LO) is the initial enzyme in the biosynthesis of leukotrienes, which are mediators involved in pathophysiological conditions such as asthma and certain cancer types. Knowledge of proteins involved in 5-LO pathway regulation, including gene regulatory proteins, is needed to evaluate all options for therapeutic intervention in these diseases. Here, we present a mass spectrometric screening of ALOX5 promoter-interacting proteins, obtained by DNA pulldown and label-free quantitative mass spectrometry. Protein preparations from myeloid and B-lymphocytic cell lines were screened for promoter DNA interactors. Through statistical analysis, 66 proteins were identified as specific ALOX5 promotor binding proteins. Among those, the 15 most likely candidates for a prominent role in ALOX5 gene regulation are the known ALOX5 interactors Sp1 and Sp3, the related factor Sp2, two Krüppel-like factors (KLF13 and KLF16) and six other zinc finger proteins (MAZ, PRDM10, VEZF1, ZBTB7A, ZNF281 and ZNF579). Intriguingly, we also identified two helicases (BLM and DHX36) and the proteins hnRNPD and hnRNPK, which are, together with the protein MAZ, known to interact with DNA G-quadruplex structures. As G-quadruplexes are implicated in gene regulation, spectroscopic and antibody-based methods were used to confirm their presence within the GC-rich sequence of the ALOX5 promoter. In summary, we have systematically characterized the interactome of the ALOX5 promoter, identifying several zinc finger proteins as novel potential ALOX5 gene regulators. Further, we have shown that the ALOX5 promoter can form DNA G-quadruplex structures, which may play a functional role in ALOX5 gene regulation.

Integrative Transcriptomics Reveals Sexually Dimorphic Control of the Cholinergic/Neurokine Interface in Schizophrenia and Bipolar Disorder

RNA sequencing analyses are often limited to identifying lowest p value transcripts, which does not address polygenic phenomena. To overcome this limitation, we developed an integrative approach that combines large-scale transcriptomic meta-analysis of patient brain tissues with single-cell sequencing data of CNS neurons, short RNA sequencing of human male- and female-originating cell lines, and connectomics of transcription factor and microRNA interactions with perturbed transcripts. We used this pipeline to analyze cortical transcripts of schizophrenia and bipolar disorder patients. Although these pathologies show massive transcriptional parallels, their clinically well-known sexual dimorphisms remain unexplained. Our method reveals the differences between afflicted men and women and identifies disease-affected pathways of cholinergic transmission and gp130-family neurokine controllers of immune function interlinked by microRNAs. This approach may open additional perspectives for seeking biomarkers and therapeutic targets in other transmitter systems and diseases.

Concentrates of two subsets of extracellular vesicles from cow's milk modulate symptoms and inflammation in experimental colitis

Extracellular vesicles (EVs) are involved in cell-to-cell communication and modulation of numerous physiological and pathological processes. EVs are found in large quantities in milk and contain several inflammation- and immunity-modulating proteins and microRNAs, through which they exert beneficial effects in several inflammatory disease models. Here, we investigated the effects of two EV subsets, concentrated from commercial cow's milk, on a murine model of colitis induced with dextran sodium sulfate (DSS). P35K EVs, isolated by ultracentrifugation at 35,000 g, and P100K EVs, isolated at 100,000 g, were previously characterized and administered by gavage to healthy and DSS-treated mice. P35K EVs and, to a lesser extent, P100K EVs improved several outcomes associated to DSS-induced colitis, modulated the gut microbiota, restored intestinal impermeability and replenished mucin secretion. Also, P35K EVs modulated innate immunity, while P100K EVs decreased inflammation through the downregulation of colitis-associated microRNAs, especially miR-125b, associated with a higher expression of the NFκB inhibitor TNFAIP3 (A20). These results suggest that different milk EV subsets may improve colitis outcomes through different, and possibly complementary, mechanisms. Further unveiling of these mechanisms might offer new opportunities for improving the life of patients with colitis and be of importance for milk processing, infant milk formulation and general public health.

Dysregulation of microRNAs and target genes networks in human abdominal aortic aneurysm tissues

BACKGROUND

Abdominal aortic aneurysm (AAA) is a pathological enlargement of infrarenal aorta close to the aortic bifurcation, and it is an important cause of mortality in the elderly. Therefore, the biomarker identification for early diagnosis is of great interest for clinical benefit. It is known that microRNAs (miRNAs) have important roles via target genes regulation in many diseases. This study aimed to identify miRNAs and their target genes involved in the pathogenesis of AAA.

METHODS

Tissue samples were obtained from patients who underwent AAA surgery and from organ donors (control group). Quantitative PCR Array was applied to assess 84 genes and 384 miRNAs aiming to identify differentially expressed targets (AAA n = 6, control n = 6), followed by validation in a new cohort (AAA n = 18, control n = 6) by regular qPCR. The functional interaction between validated miRNAs and target genes was performed by the Ingenuity Pathway Analysis (IPA) software.

RESULTS

The screening cohort assessed by PCR array identified 10 genes and 59 miRNAs differentially expressed (≥2-fold change, p<0.05). Among these, IPA identified 5 genes and 9 miRNAs with paired interaction. ALOX5, PTGIS, CX3CL1 genes, and miR-193a-3p, 125b-5p, 150-5p maintained a statistical significance in the validation cohort. IPA analysis based on the validated genes and miRNAs revealed that eicosanoid and metalloproteinase/TIMP synthesis are potentially involved in AAA.

CONCLUSION

Paired interactions of differentially expressed ALOX5, PTGIS, CX3CL1 genes, and miR-193b-3p, 125b-5p, 150-5p revealed a potentially significant role of the eicosanoid synthesis and metalloproteinase/TIMP pathways in the AAA pathogenesis.

Regulation of Eicosanoid Pathways by MicroRNAs

Over the last years, many microRNAs (miRNAs) have been identified that regulate the formation of bioactive lipid mediators such as prostanoids and leukotrienes. Many of these miRNAs are involved in complex regulatory circuits necessary for the fine-tuning of biological functions including inflammatory processes or cell growth. A better understanding of these networks will contribute to the development of novel therapeutic strategies for the treatment of inflammatory diseases and cancer. In this review, we provide an overview of the current knowledge of miRNA regulation in eicosanoid pathways with special focus on novel miRNA functions and regulatory circuits of leukotriene and prostaglandin biosynthesis.

Dysregulation of miR-125b predicts poor response to therapy in pediatric acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most well-known sort of leukemia in children. In spite of favorable survival rates, some patients relapse and achieve a poor outcome.

METHODS

We analyzed miR-125b and Bcl-2 expressions in pediatric patients with ALL and evaluated their clinical utility as molecular markers for the prediction of disease outcomes.

RESULTS

Downregulation of miR-125b and increased Bcl-2 expression levels in pediatric patients with ALL were associated with poor prognosis at diagnosis. At day 28 of induction, miR-125b was significantly increased, whereas Bcl-2 was downregulated. Loss of miR-125b during diagnosis and its elevation after therapy are strongly correlated with short leukemia-free survival and worse survival. Moreover, the combination of miR-125b with Bcl-2 markers can clearly enhance the prediction of the disease outcome. Finally, a univariate analysis highlighted the independent prognostic value of miR-125 in a pediatric patient with ALL.

CONCLUSIONS

miR-125b and Bcl-2 together are potent predictors for the prognosis and, therefore, can be used as therapeutic targets in childhood ALL.

MicroRNA-125 in immunity and cancer

MicroRNAs (miRNAs) are small non-coding RNAs that play a wide variety of critical roles in different biological processes by post-transcriptionally regulating gene expression. They access diverse regulatory pathways during various stages of cellular differentiation, growth, and apoptosis, and can contribute to both normal and diseased functions. One important family of miRNAs involved in these functions is the miR-125 family (miR-125a and miR-125b). Investigations have been made to increasingly uncover the mechanisms by which the miR-125 family regulates normal homeostasis and growth in a variety of cell types including immune cells, and how dysregulation of miR-125a and miR-125b can lead to disease pathogenesis and tumorigenesis. In this review, we summarize what is currently known about miR-125a and miR-125b, mainly focusing on their roles in immune cell development and function as well as tumor suppression and promotion.

Redox Regulation and Noncoding RNAs

SIGNIFICANCE

RNA is a heterogeneous class of molecules with the minority being protein coding. Noncoding RNAs (ncRNAs) are involved in translation and epigenetic control mechanisms of gene expression. Recent Advances: In recent years, the number of identified ncRNAs has dramatically increased and it is now clear that ncRNAs provide a complex layer of differential gene expression control.

CRITICAL ISSUES

NcRNAs exhibit interplay with redox regulation. Redox regulation alters the expression of ncRNAs; conversely, ncRNAs alter the expression of generator and effector systems of redox regulation in a complex manner, which will be the focus of this review article.

FUTURE DIRECTIONS

Understanding the role of ncRNA in redox control will lead to the development of new strategies to alter redox programs. Given that many ncRNAs (particularly microRNAs [miRNAs]) change large gene sets, these molecules are attractive drug candidates; already, now miRNAs can be targeted in patients. Therefore, the development of ncRNA therapies focusing on these molecules is an attractive future strategy. Antioxid. Redox Signal. 29, 793-812.

MicroRNAs: Mediators and Therapeutic Targets to Airway Hyper Reactivity After Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is the most important pathogen correlated to the first-time infant wheezing and later recurrence after its primary infection. RSV infection promotes the bronchial smooth muscle sensitivity to leukotrienes (LTs) in acute stage, causes the extensive inflammatory reaction and the aggregation of Th2-like cells during respiratory tract obstruction. Infants and young children infected with RSV exhibit an increased susceptibility to the exposure of exogenous allergens, easy to suffer from the recurrent wheezing, which prompts that the body is still in a state of inflammation or immunological bias. However, the pathological mechanism is unclear. The recent researches demonstrate that abnormal expression of non-coding microRNAs (miRNAs) can be detected from the peripheral blood and airway tract epithelial of RSV infected infants, which participate the regulation of immune cells polarization and LTs synthesis. Improving the immune tolerance can significantly relieve the airway inflammation and broncho-spasm caused by RSV. In this review, we discuss recent advances in understanding the mechanism of RSV-induced inflammatory reaction and immune dysfunction leading to airway hyper-reactivity. Further, we summarize the potential molecular basis that, in this process, miRNAs, which are produced by airway epithelial cells or peripheral blood mononuclear cells, directly or in the form of exosome to regulate the inflammation programs as well as the function, differentiation and proliferation of immune cells. miRNAs may become a potential bio-marker of detecting severe RSV infection and a novel target of early intervention and therapeutic strategy in recurrent wheezing or asthma related to RSV infection.

Leukotriene biosynthetic enzymes as therapeutic targets

Leukotrienes are powerful immune-regulating lipid mediators with established pathogenic roles in inflammatory allergic diseases of the respiratory tract - in particular, asthma and hay fever. More recent work indicates that these lipids also contribute to low-grade inflammation, a hallmark of cardiovascular, neurodegenerative, and metabolic diseases as well as cancer. Biosynthesis of leukotrienes involves oxidative metabolism of arachidonic acid and proceeds via a set of soluble and membrane enzymes that are primarily expressed by cells of myeloid origin. In activated immune cells, these enzymes assemble at the endoplasmic and perinuclear membrane, constituting a biosynthetic complex. This Review describes recent advances in our understanding of the components of the leukotriene-synthesizing enzyme machinery, emerging opportunities for pharmacological intervention, and the development of new medicines exploiting both antiinflammatory and pro-resolving mechanisms.

microRNA-19a protects osteoblasts from dexamethasone via targeting TSC1

Activation of mTOR complex 1 (mTORC1) could protect human osteoblasts from dexamethasone. Tuberous sclerosis complex 1 (TSC1) is mTORC1 upstream inhibitory protein. We demonstrate here that microRNA-19a (“miR-19a”, -3p) targets the 3' untranslated regions of TSC1 mRNA. Expression of miR-19a downregulated TSC1 in OB-6 osteoblastic cells and primary human osteoblasts. miR-19a activated mTORC1 and protected human osteoblasts from dexamethasone. mTORC1 inhibition, by RAD001 or Raptor shRNA, almost completely abolished miR-19a-induced osteoblast cytoprotection against dexamethasone. Knockdown of TSC1 by targeted shRNA similarly induced mTORC1 activation and protected osteoblasts. Moreover, miR-19a activated mTORC1-dependent NF-E2-related factor 2 (Nrf2) signaling and inhibited dexamethasone-induced reactive oxygen species production in osteoblasts. Together, miR-19a protects human osteoblasts from dexamethasone possibly via targeting TSC1-mTORC1 signaling.

miR-125b predicts childhood acute lymphoblastic leukaemia poor response to BFM chemotherapy treatment

BACKGROUND

Despite the favourable survival rates of childhood acute lymphoblastic leukaemia (ALL), a significant number of patients present resistance to antileukaemic agents and dismal prognosis. In this study, we analysed miR-125b expression in childhood ALL and evaluated its clinical utility for patients treated with Berlin-Frankfurt-Münster (BFM) protocol.

METHODS

The study included 272 bone marrow specimens obtained on diagnosis and on BFM day 33 from 125 patients and 64 healthy children. Following extraction, RNA was polyadenylated and reverse transcribed. miR-125b levels were quantified by quantitative PCR. Cytogenetics, immunohistotype and MRD were analysed according to international guidelines.

RESULTS

Downregulated miR-125b levels were detected in childhood ALL patients and correlated with adverse prognosis. Following BFM induction, miR-125b levels were significantly increased, however, elevated day 33/diagnosis miR-125b ratio was associated with unfavourable disease features. Loss of miR-125b during diagnosis and higher day 33/diagnosis ratio were correlated with stronger risk for disease short-term relapse and patients' worse survival. Moreover, multivariate regression models highlighted the independent prognostic value of miR-125b for childhood ALL. Finally, the combination of miR-125b with clinically used disease markers clearly enhanced the prediction of patients' resistance to BFM chemotherapy.

CONCLUSIONS

miR-125b significantly improves the prognosis of childhood ALL patients' outcome under BFM treatment.

Placenta growth factor mediated gene regulation in sickle cell disease

Sickle cell anemia (SCA) is an autosomal recessive disorder caused by mutation in the β-globin gene. Pulmonary hypertension (PH), a complication of SCA, results in severe morbidity and mortality. PH is a multifactorial disease: systemic vasculopathy, pulmonary vasoconstriction, and endothelial dysfunction and remodeling. Placenta growth factor (PlGF), an angiogenic growth factor, elaborated from erythroid cells, has been shown to contribute to inflammation, pulmonary vasoconstriction and airway hyper-responsiveness (AH) in mouse models of sickle cell disease. In this review, we summarize the cell-signaling mechanism(s) by which PlGF regulates the expression of genes involved in inflammation, PH and AH in cell culture and corroborate these findings in mouse models of SCA and in individuals with SCA. The role of microRNAs (miRNAs) in the post-transcriptional regulation of these genes is presented and how these miRNAs located in their host genes are transcriptionally regulated. An understanding of the transcriptional regulation of these miRNAs provides a new therapeutic approach to ameliorate the clinical manifestations of SCA.

Innate Immune Responses to Tuberculosis

Tuberculosis remains one of the greatest threats to human health. The causative bacterium, Mycobacterium tuberculosis, is acquired by the respiratory route. It is exquisitely adapted to humans and is a prototypic intracellular pathogen of macrophages, with alveolar macrophages being the primary conduit of infection and disease. However, M. tuberculosis bacilli interact with and are affected by several soluble and cellular components of the innate immune system which dictate the outcome of primary infection, most commonly a latently infected healthy human host, in whom the bacteria are held in check by the host immune response within the confines of tissue granuloma, the host histopathologic hallmark. Such individuals can develop active TB later in life with impairment in the immune system. In contrast, in a minority of infected individuals, the early host immune response fails to control bacterial growth, and progressive granulomatous disease develops, facilitating spread of the bacilli via infectious aerosols. The molecular details of the M. tuberculosis-host innate immune system interaction continue to be elucidated, particularly those occurring within the lung. However, it is clear that a number of complex processes are involved at the different stages of infection that may benefit either the bacterium or the host. In this article, we describe a contemporary view of the molecular events underlying the interaction between M. tuberculosis and a variety of cellular and soluble components and processes of the innate immune system.

MiR-125b Increases Nasopharyngeal Carcinoma Radioresistance by Targeting A20/NF-κB Signaling Pathway

Radioresistance poses a major challenge in nasopharyngeal carcinoma (NPC) treatment, but little is known about how miRNA regulates this phenomenon. In this study, we investigated the function and mechanism of miR-125b in NPC radioresistance, one of upregulated miRNAs in the radioresistant NPC cells identified by our previous microarray analysis. We observed that miR-125b was frequently upregulated in the radioresistant NPCs, and its increment was significantly correlated with NPC radioresistance, and was an independent predictor for poor patient survival. In vitro radioresponse assays showed that miR-125b inhibitor decreased, whereas miR-125b mimic increased NPC cell radioresistance. In a mouse model, therapeutic administration of miR-125b antagomir dramatically sensitized NPC xenografts to irradiation. Mechanistically, we confirmed that A20 was a direct target of miR-125b and found that miR-125b regulated NPC cell radioresponse by targeting A20/NF-κB signaling. With a combination of loss-of-function and gain-of-function approaches, we further showed that A20 overexpression decreased while A20 knockdown increased NPC cell radioresistance both in vitro and in vivo Moreover, A20 was significantly downregulated while p-p65 (RelA) significantly upregulated in the radioresistant NPCs relative to radiosensitive NPCs, and miR-125b expression level was negatively associated with A20 expression level, whereas positively associated with p-p65 (RelA) level. Our data demonstrate that miR-125b and A20 are critical regulators of NPC radioresponse, and high miR-125b expression enhances NPC radioresistance through targeting A20 and then activating the NF-κB signaling pathway, highlighting the therapeutic potential of the miR-125b/A20/NF-κB axis in clinical NPC radiosensitization. Mol Cancer Ther; 16(10); 2094-106. ©2017 AACR.

MiR-125b regulates proliferation and apoptosis of nasopharyngeal carcinoma by targeting A20/NF-κB signaling pathway

MiR-125b is aberrantly expressed and has a role in the various types of tumors. However, the role and mechanism of miR-125b in nasopharyngeal carcinoma (NPC) are unclear. In this study, we investigated the role and mechanism of miR-125b in NPC. We observed that miR-125b was significantly upregulated in the NPC tissues relative to normal nasopharyngeal mucosa (NNM), and its increment was correlated with poor patient survival, and was an independent predictor for reduced patient survival; miR-125b promoted NPC cell proliferation and inhibited NPC cell apoptosis; in a mouse model, administration of miR-125b antagomir significantly reduced the growth of NPC xenograft tumors. Mechanistically, we confirmed that A20 was a direct target of miR-125b, and found that activation of nuclear factor κB (NF-κB) signaling pathway by A20 mediated miR-125b-promoting NPC cell proliferation and -inhibiting NPC cell apoptosis. With a combination of loss-of-function and gain-of-function approaches, we further showed that A20 inhibited NPC cell proliferation, induced NPC cell apoptosis, and reduced the growth of NPC xenograft tumors. Moreover, A20 was significantly downregulated, whereas p-p65(RelA) was significantly upregulated in the NPC tissues relative to normal nasopharyngeal mucosa, and miR-125b level was negatively associated with A20 level, whereas positively associated with p-p65 level. Our data demonstrate that miR-125b regulates NPC cell proliferation and apoptosis by targeting A20/NF-κB signaling pathway, and miR-125b acts as oncogene, whereas A20 functions as tumor suppressor in NPC, highlighting the therapeutic potential of miR-125b/A20/NF-κB signaling axis in the NPC.

Characterization of microRNAs expression profiles in human dental-derived pluripotent stem cells

Induced pluripotent stem cells (iPSCs) technology provides a powerful means to generate and regenerate unlimited pluripotent stem cells directly from body tissue cells. Stem cells from apical papilla (SCAP) and Dental pulp stem cells (DPSCs) are present in ‘cell-rich zones’ within the dental pulp region, which are capable of regenerating pulp and dentin tissues in vivo. In this study, we investigated the difference of miRNAs expression in SCAPs and DPSCs before and after the reprogramming. Using miRNA microarray, 134 and 265 differentially expressed miRNAs in DPSCs- and SCAP-iPSCs were up-regulated compared to these before reprogramming. 117 specific miRNAs with enhanced more than 2-fold were identified in both DPSCs- and SCAP-iPSCs. Among the co-regulated miRNAs, miR-19a-3p, miR-92b-3p and miR-130b-3p showed the maximum difference, which had involvement in the cell cycle, TGF beta signaling pathway and epithelial mesenchymal transition. Using qRT-PCR analysis, the expression of miR-19a-3p, miR-92b-3p and miR-130b-3p indicated substantial increases in DPSCs-iPSCs and SCAP-iPSCs. The findings suggest that miRNAs play a part in the difference between DPSCs-iPSCs and DPSCs, as well as between SCAP-iPSCs and SCAP. The variation of miRNA expression in reprogrammed dental-derived pluripotent stem cells revealed different characteristics induced by iPSC generation.

Changes in miRNA in the lung and whole blood after whole thorax irradiation in rats

We used a rat model of whole thorax x-ray irradiation to profile the microRNA (miRNA) in lung and blood up to 4 weeks after radiation. MiRNA from normal and irradiated Wistar rat lungs and whole blood were analyzed by next-generation sequencing and the changes by radiation were identified by differential deRNA-seq 1, 2, 3 and 4 weeks after irradiation. The average total reads/library was 2,703,137 with a mean of 88% mapping to the rat genome. Detailed profiles of 100 of the most abundant miRNA in rat blood and lung are described. We identified upregulation of 4 miRNA, miR-144-5p, miR-144-3p, miR-142-5p and miR-19a-3p in rat blood 2 weeks after radiation that have not previously been shown to be altered after radiation to the lung. Ingenuity Pathway Analysis identified signaling of inflammatory response pathways. These findings will support development of early detection methods, as well as mechanism(s) of injury and mitigation in patients after radiotherapy or radiological accidents.

Characterization and cellular localization of human 5-lipoxygenase and its protein isoforms 5-LOΔ13, 5-LOΔ4 and 5-LOp12

Human 5-lipoxygenase (5-LO-WT) initiates the leukotriene (LT) biosynthesis. LTs play an important role in diseases like asthma, atherosclerosis and in many types of cancer. In this study, we investigated the 5-LO isoforms 5-LO∆13, 5-LO∆4 and 5-LOp12, lacking the exons 13, 4 or a part of exon 12, respectively. We were able to detect the mRNA of the isoforms 5-LO∆13 and 5-LOp12 in B and T cell lines as well as in primary B and T cells and monocytes. Furthermore, we found that expression of 5-LO and particularly of the 5-LO∆13 and 5-LOp12 isoforms is increased in monocytes from patients with rheumatoid arthritis and sepsis. Confocal microscopy of HEK293T cells stably transfected with tagged 5-LO-WT and/or the isoforms revealed that 5-LO-WT is localized in the nucleus whereas all isoforms are located in the cytosol. Additionally, all isoforms are catalytically inactive and do not seem to influence the specific activity of 5-LO-WT. S271A mutation in 5-LO-WT and treatment of the cells with sorbitol or KN-93/SB203580 changes the localization of the WT enzyme to the cytosol. Despite colocalization with the S271A mutant, the isoforms did not affect LT biosynthesis. Analysis of the phosphorylation pattern of 5-LO-WT and all the isoforms revealed that 5-LOp12 and 5-LO∆13 are highly phosphorylated at Ser271 and 5-LOp12 at Ser523. Furthermore, coexpression of the isoforms inhibited or stimulated 5-LO-WT expression in transiently and stably transfected HEK293T cells suggesting that the isoforms have other functions than canonical LT biosynthesis.

MiR-146 and miR-125 in the regulation of innate immunity and inflammation

Innate immune responses are primary, relatively limited, and specific responses to numerous pathogens and toxic molecules. Protein expression involved in these innate responses must be tightly regulated at both transcriptional level and post-transcriptional level to avoid the development of excessive inflammation that can be potentially harmful to the host. MicroRNAs are small noncoding RNAs (∼22 nucleotides [nts]) that participate in the regulation of numerous physiological responses by targeting specific messenger RNAs to suppress their translation. Recent work has shown that several negative regulators of transcription including microRNAs play important roles in inhibiting the exacerbation of inflammatory responses and in the maintenance of immunological homeostasis. This emerging research area will provide new insights on how microRNAs regulate innate immune signaling. It might show that dysregulation of microRNA synthesis is associated with the pathogenesis of inflammatory and infectious diseases. In this review, we focused on miR-146 and miR-125 and described the roles these miRNAs in modulating innate immune signaling. These microRNAs can control inflammatory responses and the outcomes of pathogenic infections. [BMB Reports 2016; 49(6): 311-318]

Expression Levels of Warburg-Effect Related microRNAs Correlate with each Other and that of Histone Deacetylase Enzymes in Adult Hematological Malignancies with Emphasis on Acute Myeloid Leukemia

Disruption of epigenetic regulation and characteristic metabolic alterations (known as the Warburg-effect) are well-known hallmarks of cancer. In our study we investigated the expression levels of microRNAs and histone deacetylase enzymes via RT-qPCR in bone marrow specimens of adult patients suffering from hematological malignancies (total cohort n = 40), especially acute myeloid leukemia (n = 27). The levels of the three examined Warburg-effect related microRNAs (miR-378*, miR-23b, miR-26a) positively correlated with each other and the oncogenic miR-155 and miR-125b, while negatively with the level of the tumorsuppressor miR-124. Significant relationships have been confirmed between the levels of SIRT6, HDAC4 and the microRNAs listed above. In NPM1-mutated AML (n = 6), the level of miR-125b was significantly lower than in the group of AML patients not carrying this mutation (n = 13) (p < 0.05). In M5 FAB type of AML (n = 5), the level of miR-124 was significantly higher compared to the M2 group (n = 7) (p < 0.05). In two cases of FAB M5 AML, the levels of SIRT6 and miR-26a increased during the first 4 weeks of treatment. In the total cohort, white blood cell count at the time of the diagnosis significantly correlated with the levels of HDAC4, SIRT6, miR-124 and miR-26a. Our results suggest that Warburg-effect related microRNAs may have important role in the pathogenesis of leukemia, and the potential oncogenic property of HDAC4 and SIRT6 cannot be excluded in hematological malignancies. Elevated level of miR-125b can contribute to adverse prognosis of AML without NPM1 mutation. The prevailment of the tumorsuppressor property of miR-124 may depend on the accompanying genetic alterations.

Identification and Characterization of a New Protein Isoform of Human 5-Lipoxygenase

Leukotrienes (LTs) are inflammatory mediators that play a pivotal role in many diseases like asthma bronchiale, atherosclerosis and in various types of cancer. The key enzyme for generation of LTs is the 5-lipoxygenase (5-LO). Here, we present a novel putative protein isoform of human 5-LO that lacks exon 4, termed 5-LOΔ4, identified in cells of lymphoid origin, namely the Burkitt lymphoma cell lines Raji and BL41 as well as primary B and T cells. Deletion of exon 4 does not shift the reading frame and therefore the mRNA is not subjected to non-mediated mRNA decay (NMD). By eliminating exon 4, the amino acids Trp144 until Ala184 are omitted in the corresponding protein. Transfection of HEK293T cells with a 5-LOΔ4 expression plasmid led to expression of the corresponding protein which suggests that the 5-LOΔ4 isoform is a stable protein in eukaryotic cells. We were also able to obtain soluble protein after expression in E. coli and purification. The isoform itself lacks canonical enzymatic activity as it misses the non-heme iron but it still retains ATP-binding affinity. Differential scanning fluorimetric analysis shows two transitions, corresponding to the two domains of 5-LO. Whilst the catalytic domain of 5-LO WT is destabilized by calcium, addition of calcium has no influence on the catalytic domain of 5-LOΔ4. Furthermore, we investigated the influence of 5-LOΔ4 on the activity of 5-LO WT and proved that it stimulates 5-LO product formation at low protein concentrations. Therefore regulation of 5-LO by its isoform 5-LOΔ4 might represent a novel mechanism of controlling the biosynthesis of lipid mediators.

MicroRNA-674-5p/5-LO axis involved in autoimmune reaction of Concanavalin A-induced acute mouse liver injury

Autoimmune hepatitis is characterized, in part, by the pathways involving cysteinyl-leukotriene metabolites of arachidonic acid, the dynamics of which remain unclear. Here, we explored post-transcriptional regulation in the 5-lipoxygenase (5-LO) pathway of arachidonic acid in a Concanavalin A (Con A) induced mouse model. We found that Con A administration lead to 5-LO overexpression and cysteinyl-leukotriene release in early hepatic injury, which was attenuated by cyclosporin A pretreatment. Subsequent microarray and qRT-PCR analysis further showed that microRNA-674-5p (miR-674-5p) displayed a significant decrease in expression in Con A-damaged liver. Noting that miR-674-5p harbors a potential binding region for 5-LO, we further transfected hepatic cell lines with overexpressing miR-674-5p mimic and discovered a negative regulating effect of miR-674-5p on 5-LO expression in the presence of IL-6 or TNF-α. These findings suggest that miR-674-5p might be a negative regulator in 5-LO mediated autoimmune liver injury, representing a compelling avenue towards future therapeutic interventions.

Exploration of Stereoselectivity in Embryo-Larvae (Danio rerio) Induced by Chiral PCB149 at the Bioconcentration and Gene Expression Levels

This paper was designed to study stereoselective enrichment and changes in gene expression when zebrafish (Danio rerio) embryo-larvae were exposed to racemic, (-)- or (+)- PCB149 (2,2’,3,4’,5’,6- hexachlorobiphenyl). Based on bioconcentration analysis, non-racemic enrichment was significantly observed after racemic exposure. No isomerization between the two isomers was found after (-)/(+)-PCB149 exposure. Furthermore, based on gene expression-data mining, CYPs genes (cyp2k6, cyp19a1b, and cyp2aa4) were differential genes after (+)-PCB149 exposure. No obvious differences of dysregulation of gene expression caused by racemic and (-)-PCB149, were observed in embryo-larvae. The above results suggested that (-)-PCB149 could be considered as the main factor causing the dysregulation of gene expression in embryo-larvae after racemic exposure; and (+)-PCB149 should be pursued apart from the racemate, when considering the toxicity of chiral PCB149. Thus, the information in our study could provide new insights to assess the environmental risk of chiral PCBs in aquatic systems.