Dynamic regulation of miRNA expression in ordered stages of cellular development

Non-Coding RNAs in Myasthenia Gravis: From Immune Regulation to Personalized Medicine

Myasthenia gravis (MG) is an antibody-mediated autoimmune disorder characterized by altered neuromuscular transmission, which causes weakness and fatigability in the skeletal muscles. The etiology of MG is complex, being associated with multiple genetic and environmental factors. Over recent years, progress has been made in understanding the immunological alterations implicated in the disease, but the exact pathogenesis still needs to be elucidated. A pathogenic interplay between innate immunity and autoimmunity contributes to the intra-thymic MG development. Epigenetic changes are critically involved in both innate and adaptive immune response regulation. They can act as (i) pathological factors besides genetic predisposition and (ii) co-factors contributing to disease phenotypes or patient-specific disease course/outcomes. This article reviews the role of non-coding RNAs (ncRNAs) as epigenetic factors implicated in MG. Particular attention is dedicated to microRNAs (miRNAs), whose expression is altered in MG patients' thymuses and circulating blood. The long ncRNA (lncRNA) contribution to MG, although not fully characterized yet, is also discussed. By summarizing the most recent and fast-growing findings on ncRNAs in MG, we highlight the therapeutic potential of these molecules for achieving immune regulation and their value as biomarkers for the development of personalized medicine approaches to improve disease care.

CyCoNP lncRNA establishes cis and trans RNA-RNA interactions to supervise neuron physiology

The combination of morphogenetic and transcription factors together with the synergic aid of noncoding RNAs and their cognate RNA binding proteins contribute to shape motor neurons (MN) identity. Here, we extend the noncoding perspective of human MN, by detailing the molecular and biological activity of CyCoNP (as Cytoplasmic Coordinator of Neural Progenitors) a highly expressed and MN-enriched human lncRNA. Through in silico prediction, in vivo RNA purification and loss of function experiments followed by RNA-sequencing, we found that CyCoNP sustains a specific neuron differentiation program, required for the physiology of both neuroblastoma cells and hiPSC-derived MN, which mainly involves miR-4492 and NCAM1 mRNA. We propose a novel lncRNA-mediated 'dual mode' of action, in which CyCoNP acts in trans as a classical RNA sponge by sequestering miR-4492 from its pro-neuronal targets, including NCAM1 mRNA, and at the same time it plays an additional role in cis by interacting with NCAM1 mRNA and regulating the availability and localization of the miR-4492 in its proximity. These data highlight novel insights into the noncoding RNA-mediated control of human neuron physiology and point out the importance of lncRNA-mediated interactions for the spatial distribution of regulatory molecules.

A high-resolution map of functional miR-181 response elements in the thymus reveals the role of coding sequence targeting and an alternative seed match

MicroRNAs (miRNAs) are critical post-transcriptional regulators in many biological processes. They act by guiding RNA-induced silencing complexes to miRNA response elements (MREs) in target mRNAs, inducing translational inhibition and/or mRNA degradation. Functional MREs are expected to predominantly occur in the 3' untranslated region and involve perfect base-pairing of the miRNA seed. Here, we generate a high-resolution map of miR-181a/b-1 (miR-181) MREs to define the targeting rules of miR-181 in developing murine T cells. By combining a multi-omics approach with computational high-resolution analyses, we uncover novel miR-181 targets and demonstrate that miR-181 acts predominantly through RNA destabilization. Importantly, we discover an alternative seed match and identify a distinct set of targets with repeat elements in the coding sequence which are targeted by miR-181 and mediate translational inhibition. In conclusion, deep profiling of MREs in primary cells is critical to expand physiologically relevant targetomes and establish context-dependent miRNA targeting rules.

The Effects of Resveratrol, Gallic Acid, and Piperine on the Expression of miR-17, miR-92b, miR-181a, miR-222, BAX, BCL-2, MCL-1, WT1, c-Kit, and CEBPA in Human Acute Myeloid Leukemia Cells and Their Roles in Apoptosis

MicroRNAs (miRs) play a crucial role in the leukemogenesis and the prognosis of acute myeloid leukemia (AML). This study investigated the therapeutic effects of resveratrol, gallic acid, and piperine as natural anticancer agents on the HL-60 cell line and their roles in apoptosis. In this experimental study, quantitative analysis of miRs, including miR-17, miR-92b, miR-181a, and miR-222, were performed in 150 newly diagnosed patients with AML by real-time PCR assay. HL-60 cell viability as well as the expression of miRs, BAX, BCL-2, MCL-1, WT1, c-Kit, and CEBPA, were also assessed after transfection with the LNA-miRs and treatment with resveratrol, gallic acid, and piperine. The expression of miR-17 and miR-181a decreased significantly in LNA-anti-miRs. Although HL-60 cell viability decreased in LNA-anti-miR-222, miR-17, and miR-92b, blockade of miR-181a increased the cell viability. Besides, the cell viability increased merely in the piperine-treated group. Compared to untreated cells, miR-17 and miR-92b expression significantly increased in gallic acid- and resveratrol-treated cells. In HL-60 cells treated with resveratrol, gallic acid, and piperine, the expression of miR-181a was also increased significantly. The expression of BAX was also increased in resveratrol and piperine-treated groups. Compared to untreated cells, the expression of c-Kit increased significantly in the piperine-treated group; however, it decreased in the resveratrol-treated group. LNA-anti-miRs may be a promising agent for the treatment of AML. All three compounds used in this study showed anticancer effects, which can exert the desired outcome in patients with AML.

Critical roles of the miR-17∼92 family in thymocyte development, leukemogenesis, and autoimmunity

Thymocyte development requires precise control of PI3K-Akt signaling to promote proliferation and prevent leukemia and autoimmune disorders. Here, we show that ablating individual clusters of the miR-17∼92 family has a negligible effect on thymocyte development, while deleting the entire family severely impairs thymocyte proliferation and reduces thymic cellularity, phenocopying genetic deletion of Dicer. Mechanistically, miR-17∼92 expression is induced by Myc-mediated pre-T cell receptor (TCR) signaling, and miR-17∼92 promotes thymocyte proliferation by suppressing the translation of Pten. Retroviral expression of miR-17∼92 restores the proliferation and differentiation of Myc-deficient thymocytes. Conversely, partial deletion of the miR-17∼92 family significantly delays Myc-driven leukemogenesis. Intriguingly, thymocyte-specific transgenic miR-17∼92 expression does not cause leukemia or lymphoma but instead aggravates skin inflammation, while ablation of the miR-17∼92 family ameliorates skin inflammation. This study reveals intricate roles of the miR-17∼92 family in balancing thymocyte development, leukemogenesis, and autoimmunity and identifies those microRNAs (miRNAs) as potential therapeutic targets for leukemia and autoimmune diseases.

Joint masking and self-supervised strategies for inferring small molecule-miRNA associations

Inferring small molecule-miRNA associations (MMAs) is crucial for revealing the intricacies of biological processes and disease mechanisms. Deep learning, renowned for its exceptional speed and accuracy, is extensively used for predicting MMAs. However, given their heavy reliance on data, inaccuracies during data collection can make these methods susceptible to noise interference. To address this challenge, we introduce the joint masking and self-supervised (JMSS)-MMA model. This model synergizes graph autoencoders with a probability distribution-based masking strategy, effectively countering the impact of noisy data and enabling precise predictions of unknown MMAs. Operating in a self-supervised manner, it deeply encodes the relationship data of small molecules and miRNA through the graph autoencoder, delving into its latent information. Our masking strategy has successfully reduced data noise, enhancing prediction accuracy. To our knowledge, this is the pioneering integration of a masking strategy with graph autoencoders for MMA prediction. Furthermore, the JMSS-MMA model incorporates a node-degree-based decoder, deepening the understanding of the network's structure. Experiments on two mainstream datasets confirm the model's efficiency and precision, and ablation studies further attest to its robustness. We firmly believe that this model will revolutionize drug development, personalized medicine, and biomedical research.

Regulatory RNAs in immunosenescence

BACKGROUND

Immunosenescence is a multifactorial stress response to different intrinsic and extrinsic insults that cause immune deterioration and is accompanied by genomic or epigenomic perturbations. It is now widely recognized that genes and proteins contributing in the process of immunosenescence are regulated by various noncoding (nc) RNAs, including microRNAs (miRNAs), long ncRNAs, and circular RNAs.

AIMS

This review article aimed to evaluate the regulatore RNAs roles in the process of immunosenescence.

METHODS

We analyzed publications that were focusing on the different roles of regulatory RNAs on the several aspects of immunosenescence.

RESULTS

In the immunosenescence setting, ncRNAs have been found to play regulatory roles at both transcriptional and post-transcriptional levels. These factors cooperate to regulate the initiation of gene expression programs and sustaining the senescence phenotype and proinflammatory responses.

CONCLUSION

Immunosenescence is a complex process with pivotal alterations in immune function occurring with age. The extensive network that drive immunosenescence-related features are are mainly directed by a variety of regulatory RNAs such as miRNAs, lncRNAs, and circRNAs. Latest findings about regulation of senescence by ncRNAs in the innate and adaptive immune cells as well as their role in the immunosenescence pathways, provide a better understanding of regulatory RNAs function in the process of immunosenescence.

MicroRNAs: Potential prognostic and theranostic biomarkers in chronic lymphocytic leukemia

Small noncoding ribonucleic acids called microRNAs coordinate numerous critical physiological and biological processes such as cell division, proliferation, and death. These regulatory molecules interfere with the function of many genes by binding the 3'-UTR region of target mRNAs to inhibit their translation or even degrade them. Given that a large proportion of miRNAs behave as either tumor suppressors or oncogenes, any genetic or epigenetic aberration changeing their structure and/or function could initiate tumor formation and development. An example of such cancers is chronic lymphocytic leukemia (CLL), the most prevalent adult leukemia in Western nations, which is caused by unregulated growth and buildup of defective cells in the peripheral blood and lymphoid organs. Genetic alterations at cellular and molecular levels play an important role in the occurrence and development of CLL. In this vein, it was noted that the development of this disease is noticeably affected by changes in the expression and function of miRNAs. Many studies on miRNAs have shown that these molecules are pivotal in the prognosis of different cancers, including CLL, and their epigenetic alterations (e.g., methylation) can predict disease progression and response to treatment. Furthermore, miRNAs are involved in the development of drug resistance in CLL, and targeting these molecules can be considered a new therapeutic approach for the treatment of this disease. MiRNA screening can offer important information on the etiology and development of CLL. Considering the importance of miRNAs in gene expression regulation, their application in the diagnosis, prognosis, and treatment of CLL is reviewed in this paper.

Target-induced multipath-to-one-substrate approach for high-efficient bioanalysis of microRNA

Considering the significant potential of microRNA (miRNA) as an efficient biomarker and great challenge of accurate analysis of lowly abundant miRNA, herein, we proposed a target-induced multipath-to-one-substrate strategy to monitor miRNA in vivo and in vitro accurately with high-efficient performances. In presence of target miRNA, it could directly generate the catalytic hairpin assembly (CHA) amplification cycle based on hybridizing with hairpin 1 (H1) and H2 respectively to structure the H1-H2 duplex, then the H1-H2 duplex could activate the cleavage ability of CRISPR/Cas12a to cleavage H1 which represent miRNA indirectly consume H1, which achieve co-consumption of the same substrate H1 by multiple pathways. And thus, the quenched fluorescent signal on H1 could be recovered due to the enlarger distance between fluorescent probe and quencher by the formation of H1-H2 duplex or cleavage of H1, all of which were related directly with target miRNA or indirectly with H1-H2 duplex activated cleavage ability of CRISPR/Cas12a, generating ultrahigh sensitive analytical ability and high-efficient analytical performances, such as more simple, fast, efficient and so on, especially a linear correlation from 100 pM to 100 nM with a detection limit of 78 pM, opening a new door to monitor expression level of biomolecules for early diagnosis and prognosis evaluation of various diseases.

An efficient model for predicting human diseases through miRNA based on multiple-types of contrastive learning

Multiple studies have demonstrated that microRNA (miRNA) can be deeply involved in the regulatory mechanism of human microbiota, thereby inducing disease. Developing effective methods to infer potential associations between microRNAs (miRNAs) and diseases can aid early diagnosis and treatment. Recent methods utilize machine learning or deep learning to predict miRNA-disease associations (MDAs), achieving state-of-the-art performance. However, the problem of sparse neighborhoods of nodes due to lack of data has not been well solved. To this end, we propose a new model named MTCL-MDA, which integrates multiple-types of contrastive learning strategies into a graph collaborative filtering model to predict potential MDAs. The model adopts a contrastive learning strategy based on topology, which alleviates the damage to model performance caused by sparse neighborhoods. In addition, the model also adopts a semantic-based contrastive learning strategy, which not only reduces the impact of noise introduced by topology-based contrastive learning, but also enhances the semantic information of nodes. Experimental results show that our model outperforms existing models on all evaluation metrics. Case analysis shows that our model can more accurately identify potential MDA, which is of great significance for the screening and diagnosis of real-life diseases. Our data and code are publicly available at: https://github.com/Lqingquan/MTCL-MDA.

Exploring the role of miRNAs in early chicken embryonic development and their significance

In the early stages of embryonic development, a precise and strictly controlled hierarchy of gene expression is essential to ensure proper development of all cell types and organs. To better understand this gene control process, we constructed a small RNA library from 1- to 5-day-old chick embryos, and identified 2,459 miRNAs including 827 existing, 695 known, and 937 novel miRNAs with bioinformatic analysis. There was absolute high expression of a number of miRNAs in each stage, including gga-miR-363-3p (Em1d), gga-miR-26a-5p (Em2d and Em3d), gga-miR-10a-5p (Em4d), and gga-miR-199-5p (Em5d). We evaluated enriched miRNA profiles, identifying VEGF, Insulin, ErbB, MAPK, Hedgehog, TLR and Hippo signaling pathways as primary regulatory mechanisms enabling complex morphogenetic transformations within tight temporal constraints. Pathway analysis revealed miRNAs as pivotal nodes of interaction, coordinating cascades of gene expression critical for cell fate determination, proliferation, migration, and differentiation across germ layers and developing organ systems. Weighted Gene Co-Expression Network Analysis (WGCNA) generated hub miRNAs whose modular connections spanned regulatory networks, including: gga-miR-181a-3p (blue module), coordinating immunegenesis and myogenesis; gga-miR-126-3p (brown module), regulating vasculogenesis and angiogenesis; gga-miR-302c-5p (turquoise module), enabling pluripotency and self-renew; and gga-miR-429-3p (yellow module), modulating neurogenesis and osteogenesis. The findings of this study extend the knowledge of miRNA expression in early embryonic development of chickens, providing insights into the intricate gene control process that helps ensure proper development.

High production of transfer RNAs identifies the presence of developing oocytes in ovaries and intersex testes of teleost fish

5S rRNA is highly transcribed in fish oocytes and this transcription levels can be used to identify the presence of oocytes in the intersex testes of fish exposed to xenoestrogens. Similar to 5S rRNA, tRNAs are transcribed by RNA polymerase III (Pol-III) in eukaryotes, so this study focuses in the analysis of the levels of expression of tRNAs in the gonads (ovaries and testes) of eight teleost species as a possible new oocyte molecular marker. Total RNA extracted from gonads of six commercial teleost species in the Biscay Bay, from the pollution sentinel species thicklip grey mullet (Chelon labrosus) known present intersex testes in response to xenoestrogens in Gernika estuary and from the laboratory model species Danio rerio were analysed through capillary electrophoresis. Bioanalyzer electropherograms were used to quantify the concentrations of tRNAs, 5S and 5.8S rRNA. All studied ovaries expressed significantly higher levels of tRNAs and 5S rRNA than testes. A tRNA to 5.8S rRNA index was calculated which differentiates ovaries from testes, and identifies some intersex testes in between testes and ovaries in mullets. The tRNA/5.8S ratio was highest in ovaries in previtellogenic stage, decreasing towards maturity. Thus, strong oocyte expression of tRNAs is an additional proof of high activity levels of Pol-III during early stages of oocyte development in teleost ovaries. Incidentally, we observed that miRNA concentrations were always higher in testes than ovaries. The indexing approach developed in the present study could have multiple applications in teleost reproduction research and in the development of early molecular markers of intersex condition.

MicroRNA‑155 modulation of CD8+ T‑cell activity personalizes response to disease‑modifying therapies of patients with relapsing‑remitting multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease where activated immune cells can attack oligodendrocytes causing damage to the myelin sheath. Several molecular mechanisms are responsible for the auto-activation of immune cells such as RNA interference (RNAi) through microRNAs (miRNAs or miRs). In the present study, the role of miR-155 in regulating CD8⁺ T-cell activity in patients with relapsing-remitting multiple sclerosis (RRMS) was investigated, in terms of its migratory functions with regard to intracellular adhesion molecule-1 (ICAM1) and integrin subunit β2 (ITGB2), and its cytotoxic proteins, perforin and granzyme B. Gene expression of miR-155, ICAM1, ITGB2, perforin and granzyme B was evaluated following epigenetic modulations using reverse transcription-quantitative polymerase chain reaction in CD8⁺ T-cells isolated from blood samples of patients with RRMS and compared to healthy controls. The ectopic expression of miR-155 resulted in a persistent downregulation in all genes of interest related to CD8⁺ T-cell activation that were positively correlated with the Expanded Disability Status Scale of patients. The present study revealed the interplay between miR-155, ICAM1, and ITGB2, shedding light on their beneficial use as possible therapeutic regulators and diagnostic biomarkers of disease. Moreover, epigenetic modulations enhancing the efficacy of disease-modifying therapies (DMTs) may be employed as personalized therapy, to decrease the side effects of DMTs and improve the outcomes of patients.

miR-20a is upregulated in serum from domestic feline with PKD1 mutation

Polycystic kidney disease (PKD), also known as autosomal dominant polycystic kidney disease (ADPKD) is a genetically heterogeneous condition characterized by cysts in renal parenchyma. It is the most prevalent inherited disease of domestic cats. MicroRNAs (miRNAs or ncRNA) are short, noncoding, single-stranded RNAs that may induce PKD cytogenesis by affecting numerous targets genes as well as by directly regulating PKD gene expression. We compared the relative expression profile of miR-20a, -192, -365, -15b-5p, and -16-5p from plasma and serum samples of nine domestic cats with PKD1 mutation, detected by polymerase chain reaction (PCR), and a control group (n = 10). Blood samples from cats with PKD1 mutation provide similar concentrations of microRNAs either from plasma or serum. Serum miR-20a is upregulated in PKD group with p < 0.005; Roc curve analysis showed an AUC of 90,1% with a cut-off value sensitivity of 77.8% and specificity of 100%. This data provides important information regarding renal miRNA expression in peripheral blood sampling.

MicroRNAs in the regulation of Th17/Treg homeostasis and their potential role in uveitis

Th17 and regulatory T cells (Tregs) play crucial roles in the pathogenesis of autoimmune diseases. Th17/Treg homeostasis is critically involved in maintaining the immune balance. Disturbed Th17/Treg homeostasis contributes to the progression of autoimmune diseases. MicroRNAs (miRNAs) have emerged as a new vital factor in the regulation of disturbed Th17/Treg homeostasis. To better understand the epigenetic mechanisms of miRNAs in regulating Treg/Th17 homeostasis, we included and evaluated 97 articles about autoimmune diseases and found that miRNAs were involved in the regulation of Treg/Th17 homeostasis from several aspects positively or negatively, including Treg differentiation and development, Treg induction, Treg stability, Th17 differentiation, and Treg function. Uveitis is one of the ocular autoimmune diseases, which is also characterized with Th17/Treg imbalance. However, our understanding of the miRNAs in the pathogenesis of uveitis is elusive and not well-studied. In this review, we further summarized miRNAs found to be involved in autoimmune uveitis and their potential role in the regulation of Th17/Treg homeostasis.

Detection of Pancreatic Cancer miRNA with Biocompatible Nitrogen-Doped Graphene Quantum Dots

Early-stage pancreatic cancer remains challenging to detect, leading to a poor five-year patient survival rate. This obstacle necessitates the development of early detection approaches based on novel technologies and materials. In this work, the presence of a specific pancreatic cancer-derived miRNA (pre-miR-132) is detected using the fluorescence properties of biocompatible nitrogen-doped graphene quantum dots (NGQDs) synthesized using a bottom-up approach from a single glucosamine precursor. The sensor platform is comprised of slightly positively charged (1.14 ± 0.36 mV) NGQDs bound via π-π stacking and/or electrostatic interactions to the negatively charged (-22.4 ± 6.00 mV) bait ssDNA; together, they form a complex with a 20 nm average size. The NGQDs' fluorescence distinguishes specific single-stranded DNA sequences due to bait-target complementarity, discriminating them from random control sequences with sensitivity in the micromolar range. Furthermore, this targetability can also detect the stem and loop portions of pre-miR-132, adding to the practicality of the biosensor. This non-invasive approach allows cancer-specific miRNA detection to facilitate early diagnosis of various forms of cancer.

Hsa-miR-422a Originated from Short Interspersed Nuclear Element Increases ARID5B Expression by Collaborating with NF-E2

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate the expression of target messenger RNA (mRNA) complementary to the 3' untranslated region (UTR) at the post-transcriptional level. Hsa-miR-422a, which is commonly known as miRNA derived from transposable element (MDTE), was derived from short interspersed nuclear element (SINE). Through expression analysis, hsa-miR-422a was found to be highly expressed in both the small intestine and liver of crab-eating monkey. AT-Rich Interaction Domain 5 B (ARID5B) was selected as the target gene of hsa-miR-422a, which has two binding sites in both the exon and 3'UTR of ARID5B. To identify the interaction between hsa-miR-422a and ARID5B, a dual luciferase assay was conducted in HepG2 cell line. The luciferase activity of cells treated with the hsa-miR-422a mimic was upregulated and inversely downregulated when both the hsa-miR-422a mimic and inhibitor were administered. Nuclear factor erythroid-2 (NF-E2) was selected as the core transcription factor (TF) via feed forward loop analysis. The luciferase expression was downregulated when both the hsa-miR-422a mimic and siRNA of NF-E2 were treated, compared to the treatment of the hsa-miR-422a mimic alone. The present study suggests that hsa-miR-422a derived from SINE could bind to the exon region as well as the 3'UTR of ARID5B. Additionally, hsa-miR-422a was found to share binding sites in ARID5Bwith several TFs, including NF-E2. The hsa-miR-422a might thus interact with TF to regulate the expression of ARID5B, as demonstrated experimentally. Altogether, hsa-miR-422a acts as a super enhancer miRNA of ARID5Bby collaborating with TF and NF-E2.

MDV-induced differential microRNA expression in the primary lymphoid organ of thymus

Marek's disease virus (MDV), a highly contagious cell associated virus, is the etiological agent of Marek's disease (MD), a lymphoproliferative and neuropathic disease of domestic chickens. Clinical signs of MD include transient paralysis, bursal/thymic atrophy, and T cell lymphomas. MicroRNAs (miRNAs) are short single-stranded non-coding RNAs that regulate gene expression by transcriptional suppression or mRNA degradation. Herpesviruses, including MDV, encode for miRNAs that are known to play essential roles in viral pathogenicity, oncogenesis, and evasion of immune responses. In this study, we performed miRNA sequencing in thymuses of control and MDV-infected chickens of MD-resistant (6₃) and susceptible (7₂) lines at 21 days post infection (dpi). The thymus is a lymphoid organ that undergoes severe atrophy due to MDV-induced apoptotic mediated destruction of T cells. Sequence analysis identified 658 total chicken miRNAs in the thymuses of control and MDV-infected birds of both lines. Of these, 453 were novel and 205 were known microRNAs. All novel miRNAs mapped to chicken genome with no sequence homology to existing miRNAs in the chicken miRbase. Comparative analysis between the thymuses of control and infected birds of resistant and susceptible lines identified 78 differentially expressed microRNAs that might provide insights into mechanisms of thymus atrophy.

Exosome Carrier Effects; Resistance to Digestion in Phagolysosomes May Assist Transfers to Targeted Cells; II Transfers of miRNAs Are Better Analyzed via Systems Approach as They Do Not Fit Conventional Reductionist Stoichiometric Concepts

Carrier effects of extracellular vesicles (EV) like exosomes refer to properties of the vesicles that contribute to the transferred biologic effects of their contents to targeted cells. This can pertain to ingested small amounts of xenogeneic plant miRNAs and oral administration of immunosuppressive exosomes. The exosomes contribute carrier effects on transfers of miRNAs by contributing both to the delivery and the subsequent functional intracellular outcomes. This is in contrast to current quantitative canonical rules that dictate just the minimum copies of a miRNA for functional effects, and thus successful transfers, independent of the EV carrier effects. Thus, we argue here that transfers by non-canonical minute quantities of miRNAs must consider the EV carrier effects of functional low levels of exosome transferred miRNA that may not fit conventional reductionist stoichiometric concepts. Accordingly, we have examined traditional stoichiometry vs. systems biology that may be more appropriate for delivered exosome functional responses. Exosome carrier properties discussed include; their required surface activating interactions with targeted cells, potential alternate targets beyond mRNAs, like reaching a threshold, three dimensional aspects of the RNAs, added EV kinetic dynamic aspects making transfers four dimensional, and unique intracellular release from EV that resist intracellular digestion in phagolysosomes. Together these EV carrier considerations might allow systems analysis. This can then result in a more appropriate understanding of transferred exosome carrier-assisted functional transfers. A plea is made that the miRNA expert community, in collaboration with exosome experts, perform new experiments on molecular and quantitative miRNA functional effects in systems that include EVs, like variation in EV type and surface constituents, delivery, dose and time to hopefully create more appropriate and truly current canonical concepts of the consequent miRNA functional transfers by EVs like exosomes.

MiR-652-5p elevated glycolysis level by targeting TIGAR in T-cell acute lymphoblastic leukemia

The effect of glycolysis remains largely elusive in acute T lymphoblastic leukemia (T-ALL). Increasing evidence has indicated that the dysregulation of miRNAs is involved in glycolysis, by targeting the genes coding glycolysis rate-limiting enzymes. In our previous studies, we found that overexpression of the ARRB1-derived miR-223 sponge repressed T-ALL progress and reduced the expression of miR-652-5p. However, little is known about miR-652-5p on T-ALL. Here, we showed that impaired miR-652-5p expression inhibited growth, promoted apoptosis of T-ALL cells in vitro and prolonged overall survival (OS) in vivo. Based on the GO enrichment of miR-652-5p target genes, we uncovered that impaired miR-652-5p decreased glycolysis, including reduced the lactate, pyruvate, ATP level and the total extracellular acidification rate (ECAR), elevated oxygen consumption rate (OCR) in T-ALL cell lines. Mechanically, miR-652-5p targeted the 3ʹUTR of Tigar mRNA and inhibited its expression. Furthermore, the alteration of glycosis level was attributed to Tigar overexpression, consistent with the effect of impaired miR-652-5p. Additionally, Tigar suppressed the expression of PFKFB3, a glycolysis rate-limiting enzyme, in vivo and in vitro. Taken together, our results demonstrate that impaired miR-652-5p/Tigar axis could repress glycolysis, thus to slow growth of T-ALL cells, which support miR-652-5p as a novel potential drug target for T-ALL therapeutics.

A target-initiated autocatalytic 3D DNA nanomachine for high-efficiency amplified detection of MicroRNA

Considering the challenges of generating simple and efficient DNA (deoxyribonucleic acid) nanomachines for sensitive bioassays and the great potential of target-induced self-cycling catalytic systems, herein, a novel autocatalytic three-dimensional (3D) DNA nanomachine was constructed based on cross-catalytic hairpin assembly on gold nanoparticles (AuNPs) to generate self-powered efficient cyclic amplification. Typically, the DNA hairpins H1, H2, H3 and H4 were immobilized onto AuNPs first. In the presence of target microRNA-203a, the 3D DNA nanomachines were triggered to activate a series of CHA (catalytic hairpin assembly) reactions. Based on the rational design of the system, the products of the CHA 1 reaction were the trigger of the CHA 2 reaction, which could trigger the CHA 1 reaction in turn, generating an efficient self-powered CHA amplification strategy without adding fuel DNA strands or protein enzymes externally and producing high-efficiency fluorescence signal amplification. More importantly, the proposed autocatalytic 3D DNA nanomachines outperformed conventional 3D DNA nanomachines combined with the single-directional cyclic amplification strategy to maximize the amplification efficiency. This strategy not only achieves high-efficiency analysis of microRNAs (microribonucleic acids) in vitro and intracellularly but also provides a new pathway for highly processive DNA nanomachines, offering a new avenue for bioanalysis and early clinical diagnosis.

MicroRNA-181a restricts human γδ T cell differentiation by targeting Map3k2 and Notch2

γδ T cells are a conserved population of lymphocytes that contributes to anti-tumor responses through its overt type 1 inflammatory and cytotoxic properties. We have previously shown that human γδ T cells acquire this profile upon stimulation with IL-2 or IL-15, in a differentiation process dependent on MAPK/ERK signaling. Here, we identify microRNA-181a as a key modulator of human γδ T cell differentiation. We observe that miR-181a is highly expressed in patients with prostate cancer and that this pattern associates with lower expression of NKG2D, a critical mediator of cancer surveillance. Interestingly, miR-181a expression negatively correlates with an activated type 1 effector profile obtained from in vitro differentiated γδ T cells and miR-181a overexpression restricts their levels of NKG2D and TNF-α. Upon in silico analysis, we identify two miR-181a candidate targets, Map3k2 and Notch2, which we validate via overexpression coupled with luciferase assays. These results reveal a novel role for miR-181a as critical regulator of human γδ T cell differentiation and highlight its potential for manipulation of γδ T cells in next-generation immunotherapies.

A regulatory network of microRNAs confers lineage commitment during early developmental trajectories of B and T lymphocytes

The commitment of hematopoietic multipotent progenitors (MPPs) toward a particular lineage involves activation of cell type-specific genes and silencing of genes that promote alternate cell fates. Although the gene expression programs of early-B and early-T lymphocyte development are mutually exclusive, we show that these cell types exhibit significantly correlated microRNA (miRNA) profiles. However, their corresponding miRNA targetomes are distinct and predominated by transcripts associated with natural killer, dendritic cell, and myeloid lineages, suggesting that miRNAs function in a cell-autonomous manner. The combinatorial expression of miRNAs miR-186-5p, miR-128-3p, and miR-330-5p in MPPs significantly attenuates their myeloid differentiation potential due to repression of myeloid-associated transcripts. Depletion of these miRNAs caused a pronounced de-repression of myeloid lineage targets in differentiating early-B and early-T cells, resulting in a mixed-lineage gene expression pattern. De novo motif analysis combined with an assay of promoter activities indicates that B as well as T lineage determinants drive the expression of these miRNAs in lymphoid lineages. Collectively, we present a paradigm that miRNAs are conserved between developing B and T lymphocytes, yet they target distinct sets of promiscuously expressed lineage-inappropriate genes to suppress the alternate cell-fate options. Thus, our studies provide a comprehensive compendium of miRNAs with functional implications for B and T lymphocyte development.

Differential Leukocyte MicroRNA Responses Following Pan T Cell, Allorecognition and Allosecretome-Based Therapeutic Activation

Effective immunomodulation of T-cell responses is critical in treating both autoimmune diseases and cancer. Our previous studies have demonstrated that secretomes derived from control or methoxypolyethylene glycol mixed lymphocyte alloactivation assays exerted potent immunomodulatory activity that was mediated by microRNAs (miRNA). The immunomodulatory effects of biomanufactured miRNA-based allo-secretome therapeutics (SYN, TA1, IA1 and IA2) were compared to Pan T-cell activators (PHA and anti-CD3/CD28) and lymphocyte alloactivation. The differential effects of these activation strategies on resting peripheral blood mononuclear cells (PBMC) were assessed via T-cell proliferation, subset analysis and miRNA expression profiles. Mitogen-induced PBMC proliferation (> 85%) significantly exceeded that arising from either allostimulation (~ 30%) or the pro-inflammatory IA1 secretome product (~ 12%). Consequent to stimulation, the ratio of CD4 to CD8 cells of the resting PBMC (CD4:CD8; 1.7 ± 0.1) decreased in the Pan T cell, allrecognition and IA1 activated cells (averages of 1.1 ± 0.2; 1.2 ± 0.1 and 1.0 ± 0.1). These changes arose consequent to the expansion of both CD4⁺CD8⁺ and CD4^–CD8^– populations as well as the shrinkage of the CD4 subset and the expansion of the CD8 T cells. Importantly, these activation strategies induced vastly different miRNA expression profiles which were associated with significant differences in cellular differentiation and biological function. These findings support the concept that the “differential patterns of miRNA expression” regulate the biologic immune response in a “lock and key” manner. The biomanufacturing of miRNA-enriched secretome biotherapeutics may be a successful therapeutic approach for the systemic treatment of autoimmune diseases (TA1) and cancer (IA1).

A hidden threshold in motor neuron gene networks revealed by modulation of miR-218 dose

Disruption of homeostatic microRNA (miRNA) expression levels is known to cause human neuropathology. However, the gene regulatory and phenotypic effects of altering a miRNA's in vivo abundance (rather than its binary gain or loss) are not well understood. By genetic combination, we generated an allelic series of mice expressing varying levels of miR-218, a motor neuron-selective gene regulator associated with motor neuron disease. Titration of miR-218 cellular dose unexpectedly revealed complex, non-ratiometric target mRNA dose responses and distinct gene network outputs. A non-linearly responsive regulon exhibited a steep miR-218 dose-dependent threshold in repression that, when crossed, resulted in severe motor neuron synaptic failure and death. This work demonstrates that a miRNA can govern distinct gene network outputs at different expression levels and that miRNA-dependent phenotypes emerge at particular dose ranges because of hidden regulatory inflection points of their underlying gene networks.

MicroRNA-7 overexpression positively regulates the CD8+ SP cell development via targeting PIK3R1

microRNA-7 (miR-7), a distinct miRNA family member, has been reported to be involved in the biological functions of immune cells. However, the potential role of miR-7 in the CD8⁺ T cell development remains to be elucidated. In this study, we estimated the potential effects of miR-7 overexpression in the thymic CD8⁺ SP cell development using miR-7 overexpression mice. Our results showed that compared with those in control wild type (WT) mice, the volume, weight and total cell numbers of thymus in miR-7 overexpression (OE) mice increased significantly. The absolute cell number of CD8⁺ SP cells in miR-7 OE mice increased and its ability of activation and proliferation enhanced. Futhermore, we clarified that miR-7 overexpression had an intrinsic promote role in CD8⁺ SP cell development by adoptive cell transfer assay. Mechanistically, the expression level of PIK3R1, a target of miR-7, decreased significantly in CD8⁺ SP cells of miR-7 OE mice. Moreover, the expression level of phosphorylated (p)-AKT and p-ERK changed inversely and indicating that miR-7 overexpression impaired the balance of AKE and ERK pathways. In summary, our work reveals an essential role of miR-7 in promoting CD8⁺ SP cell development through the regulation of PIK3R1 and balance of AKT and ERK pathways.

miR-184 delays cell proliferation, migration and invasion in prostate cancer by directly suppressing DLX1

A number of previous studies have reported that dysregulated miR-184 expression is associated with the development of cancer. The aim of the present study was to investigate the role of miR-184 in prostate cancer (PC) and the mechanism underlying its effects. Data from human tumor tissue samples were collected from The CEancer Genome Atlas to determine the expression levels of miR-184 and DLX1. The miR-184 mimic and pcDNA3.1-DLX1 plasmid were utilized to induce overexpression of miR-184 and DLX1 in Du145 cells, respectively. Cell Counting Kit-8, wound healing and Transwell assays were performed to examine the effects of miR-184 on the aggressiveness of PC cells. Dual-luciferase reporter gene assay was used to investigate the association between miR-184 and DLX1, and reverse transcription-quantitative PCR and western blot analyses were utilized to determine the mRNA and protein levels. miR-184 expression was found to be downregulated whereas DLX1 was upregulated in PC tissues compared with normal prostate tissues. Cell propagation, migration and invasion were all inhibited by miR-184 upregulation in Du145 cells. Dual luciferase reporter assay confirmed the association between miR-184 and DLX1. The inhibitory effect of miR-184 mimic on cell behaviors was reversed by upregulation of DLX1. These findings suggest that miR-184 plays a beneficial role in suppressing the tumorigenesis of PC by directly targeting DLX1, and it may represent a potential therapeutic strategy for PC.

Regulatory roles of MicroRNA in shaping T cell function, differentiation and polarization

T lymphocytes are an integral component of adaptive immunity with pleotropic effector functions. Impairment of T cell activity is implicated in various immune pathologies including autoimmune diseases, AIDS, carcinogenesis, and periodontitis. Evidently, T cell differentiation and function are under robust regulation by various endogenous factors that orchestrate underlying molecular pathways. MicroRNAs (miRNA) are a class of noncoding, regulatory RNAs that post-transcriptionally control multiple mRNA targets by sequence-specific interaction. In this article, we will review the recent progress in our understanding of miRNA-gene networks that are uniquely required by specific T cell effector functions and provide miRNA-mediated mechanisms that govern the fate of T cells. A subset of miRNAs may act in a synergistic or antagonistic manner to exert functional suppression of genes and regulate pathways that control T cell activation and differentiation. Significance of T cell-specific miRNAs and their dysregulation in immune-mediated diseases is discussed. Exosome-mediated horizontal transfer of miRNAs from antigen presenting cells (APCs) to T cells and from one T cell to another T cell subset and their impact on recipient cell functions is summarized.

microRNA dynamic expression regulates invariant NKT cells

Invariant natural killer T cells (iNKT) are a prevalent population of innate-like T cells in mice, but quite rare in humans that are critical for regulation of the innate and adaptive immune responses during antimicrobial immunity, tumor rejection, and inflammatory diseases. Multiple transcription factors and signaling molecules that contribute to iNKT cell selection and functional differentiation have been identified. However, the full molecular network responsible for regulating and maintaining iNKT populations remains unclear. MicroRNAs (miRNAs) are an abundant class of evolutionarily conserved, small, non-coding RNAs that regulate gene expression post-transcriptionally. Previous reports uncovered the important roles of miRNAs in iNKT cell development and function using Dicer mutant mice. In this review, we discuss the emerging roles of individual miRNAs in iNKT cells reported by our group and other groups, including miR-150, miR-155, miR-181, let-7, miR-17 ~ 92 cluster, and miR-183-96-182 cluster. It is likely that iNKT cell development, differentiation, homeostasis, and functions are orchestrated through a multilayered network comprising interactions among master transcription factors, signaling molecules, and dynamically expressed miRNAs. We provide a comprehensive view of the molecular mechanisms underlying iNKT cell differentiation and function controlled by dynamically expressed miRNAs.

miR-98-5p protects against cerebral ischemia/reperfusion injury through anti-apoptosis and anti-oxidative stress in mice

Cerebral ischemia/reperfusion (I/R) injury is an obstacle in treating ischemic stroke effectively. miR-98-5p has been reported to have the ability of reducing myocardial I/R injury. To explore the function of miR-98-5p in cerebral I/R, we established mice model of middle cerebral artery occlusion and reperfusion (MCAO/R). The level of miR-98-5p was found to be downregulated in serum of stroke patients and brain tissues of MCAO/R mice. Examination of brain tissues indicated that upregulating miR-98-5p level alleviated the infarction in MCAO/R mice. Moreover, the upregulation of miR-98-5p reduced reactive oxygen species production and enhanced superoxide dismutase activity in brain tissues of MCAO/R mice. These results indicating that miR-98-5p could protect against oxidative stress. Further study showed that miR-98-5p inhibited apoptosis by reducing the levels of death-associated protein kinase 1, B cell lymphoma/leukaemia-2 associated x protein and cleaved caspase-3, as well as increasing the level of B cell lymphoma/leukaemia-2. In addition, miR-98-5p was found to protect against oxidative stress through downregulating the level of BTB domain and CNC homology 1 and upregulating the levels of NAD(P)H: quinone oxidoreductase 1 and heme oxygenase 1. Therefore, miR-98-5p might be a potential target to treat cerebral I/R injury.

miR-181a-regulated pathways in T-cell differentiation and aging

MicroRNAs (miRNAs) are regulatory noncoding RNAs important for many aspects of cellular processes including cell differentiation and proliferation. Functions of numerous miRNAs have been identified in T cells, with miR-181a regulating T cell activation thresholds during thymic T cell development and during activation of peripheral T cells. Intriguingly, miR-181a is implicated in defective antiviral and vaccine responses in older individuals, as its expression declines in naïve T cells with increasing age. Here, we review the pathways that are regulated by miR-181a and that explain the unique role of miR-181a in T cell development, T cell activation and antiviral T cell responses. These studies provide a framework for understanding how a decline in miR-181a expression in T cells could contribute to age-related defects in adaptive immunity. We furthermore review the mechanisms that cause the age-related decline in miR-181a expression and discuss the potential of restoring miR-181a expression or targeting miR-181a-regulated pathways to improve impaired T cell responses in older individuals.

miR-155 and functional proteins of CD8+ T cells as potential prognostic biomarkers for relapsing-remitting multiple sclerosis

BACKGROUND

Multiple Sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) that results in neurological deficits in patients leading to disabilities which are evaluated on a scale known as the Expanded Disability Status Scale (EDSS). The most prevalent subtype of the disease is Relapsing-Remitting Multiple sclerosis (RRMS). One of the key players in MS pathogenesis is CD8+ T cells present in abundance in MS lesions expressing surface receptors, intracellular adhesion molecule (ICAM1) and integrin Subunit Beta 2 (ITGB2). These proteins are crucial for migration through the blood-brain barrier (BBB) and secondary stimulatory signal, along with the cytotoxic proteins perforin and granzymeB that attack oligodendrocytes. MicroRNAs (miRNAs) are small non-coding RNAs that play a substantial regulatory role in various disease pathogeneses through post-transcriptional modifications, and miR-155 shows potential for its use as a biomarker of the disease. The study aims at investigating the expression of miR-155, ICAM1, ITGB2, perforin and GranzymeB in CD8+ T cells of RRMS patients receiving different treatment regimens and how these genes correlate with patients' EDSS and miR-155 expression.

METHODS

Gene expression of miR-155, ICAM1, ITGB2, perforin and granzymeB was evaluated using RT-qPCR in CD8+ T cells isolated from blood samples of RRMS patients and compared to healthy controls.

RESULTS

Results showed downregulation of miR-155 and upregulation of surface receptors and cytotoxic proteins in CD8+T cells with significant correlation with each other and patients' EDSS.

CONCLUSION

This study helps pave the road for the discussed genes for their use as potential biomarkers of disease disability and future investigations on their regulatory roles in disease pathogenesis.

A fluorescent microarray platform based on catalytic hairpin assembly for MicroRNAs detection

The DNA microarray has distinctive advantages of high-throughput and less complicated operations, but tends to have a relatively low sensitivity. Catalytic hairpin assembly (CHA) is one of the most promising enzyme-free, isothermal DNA circuit for high efficient signal amplification. Here, a microarray-based catalytic hairpin assembly (mi-CHA) biosensing method has been developed to detect various miRNAs in a single test simultaneously. The target miRNA can trigger conformational transformations of hairpin-structured DNA probes on the chip surface and lead to the specific signal amplification. A significant advantage of this approach is that each duplex produced by the solid-phase CHA will be immobilized on the certain location of the chip and release fluorescent signal via the universal domain, eliminating the requirement of different fluorophores. This method has manifested a high detection sensitivity of human cancer-associated miRNAs (miR-21 and miR-155) down to 1.33 fM and promised a high specificity to distinguish single-base mismatches. Furthermore, the practicability of this method was demonstrated by analyzing target miRNAs in human serum and cancer cells. The experimental results suggest that the proposed method has high-throughput analytical potential and could be applied to many other clinical diagnosis.

Adipocyte, Immune Cells, and miRNA Crosstalk: A Novel Regulator of Metabolic Dysfunction and Obesity

Obesity is characterized as a complex and multifactorial excess accretion of adipose tissue (AT) accompanied with alterations in the immune response that affects virtually all age and socioeconomic groups around the globe. The abnormal accumulation of AT leads to several metabolic diseases, including nonalcoholic fatty liver disorder (NAFLD), low-grade inflammation, type 2 diabetes mellitus (T2DM), cardiovascular disorders (CVDs), and cancer. AT is an endocrine organ composed of adipocytes and immune cells, including B-Cells, T-cells and macrophages. These immune cells secrete various cytokines and chemokines and crosstalk with adipokines to maintain metabolic homeostasis and low-grade chronic inflammation. A novel form of adipokines, microRNA (miRs), is expressed in many developing peripheral tissues, including ATs, T-cells, and macrophages, and modulates the immune response. miRs are essential for insulin resistance, maintaining the tumor microenvironment, and obesity-associated inflammation (OAI). The abnormal regulation of AT, T-cells, and macrophage miRs may change the function of different organs including the pancreas, heart, liver, and skeletal muscle. Since obesity and inflammation are closely associated, the dysregulated expression of miRs in inflammatory adipocytes, T-cells, and macrophages suggest the importance of miRs in OAI. Therefore, in this review article, we have elaborated the role of miRs as epigenetic regulators affecting adipocyte differentiation, immune response, AT browning, adipogenesis, lipid metabolism, insulin resistance (IR), glucose homeostasis, obesity, and metabolic disorders. Further, we will discuss a set of altered miRs as novel biomarkers for metabolic disease progression and therapeutic targets for obesity.

DNA Strands Trigger the Intracellular Release of Drugs from Mucin-Based Nanocarriers

Gaining control over the delivery of therapeutics to a specific disease site is still very challenging. However, especially when cytotoxic drugs such as chemotherapeutics are used, the importance of a control mechanism that can differentiate "sick" target cells from the surrounding healthy tissue is pivotal. Here, we designed a nanoparticle-based drug delivery process, which releases an active agent only in the presence of a specific trigger DNA sequence. With this strategy, we are able to initiate the release of therapeutics into the cytosol with high efficiency. Furthermore, we demonstrate how an endogenous marker (e.g., a specific miRNA sequence) that is overexpressed in the initial phases of certain cancer types can be used as a stimulus to autonomously initiate intracellular drug release-and only in cells where this pathophysiological marker is present. We expect that this precisely controlled delivery mechanism can facilitate the design of site-specific treatments for such diseases, where an overexpression of signature oligonucleotide sequences has been identified.

Demethylation of miR-34a upregulates expression of membrane palmitoylated proteins and promotes the apoptosis of liver cancer cells

BACKGROUND

Liver cancer is a common cancer and the main cause of cancer-related deaths worldwide. Liver cancer is the sixth most common cancer in the world. Although miR-34a and palmitoyl membrane palmitoylated protein (MPP2) are reportedly involved in various cell processes, their precise roles in liver cancer are still unclear.

AIM

To investigate the expression of micro RNA 34a (miR-34a), methylation of the miR-34a promoter and the expression of MPP2 in liver cancer cells and their related mechanisms.

METHODS

Together, 78 cases of liver cancer tissues and 78 cases of adjacent tissues were collected. The methylation degree of miR-34a promoter in liver cancer/ paracancerous tissue and liver cancer cells/normal liver cells, and the expression levels of miR-34a and MPP2 in the above samples were detected. Demethylation of liver cancer cells or transfection of liver cancer cells with miR-34a mimetic was performed. The MPP2 overexpression vector was used to transfect liver cancer cells, and the changes in proliferation, invasion, apoptosis, migration, and other biological functions of liver cancer cells after the above interventions were observed. Double luciferase reporter genes were used to detect the targeting relationship between miR-34a and MPP2.

RESULTS

Clinical samples showed that the expression levels of miR-34a and MPP2 in liver cancer tissues were lower than those in the normal tissues. The methylation degree of miR-34a promoter region in liver cancer cells was higher than that in normal liver cells. After miR-34a demethylation/mimetic transfection/MPP2 overexpression, the apoptosis of liver cancer cells was increased; the proliferation, invasion and migration capabilities were decreased; the expression levels of caspase 3, caspase 9, E-cadherin, and B-cell lymphoma 2 (Bcl-2)-associated X protein were increased; and the expression levels of Bcl-2, N-cadherin, and β-catenin were decreased. Double luciferase reporter genes confirmed that MPP2 is targeted by miR-34a. Rescue experiments showed that small interfering MPP2 could counteract the promoting effect of miR-34a demethylation on apoptosis and the inhibitory effect on cell proliferation, invasion, and migration.

CONCLUSION

miR-34a demethylation upregulates the expression level of MPP2 in liver cancer cells and promotes the apoptosis of liver cancer cells. miR-34a demethylation is a potential method for liver cancer treatment.

Argonaute Proteins Take Center Stage in Cancers

Simple Summary

The dysregulation of RNA interference (RNAi) has often been observed in cancers, where the main focus of research has been on the small RNA molecules directing RNAi. In this review, we focus on the activity of Argonaute proteins, central components of RNAi, in tumorigenesis, and also highlight their potential applications in grading tumors and anti-cancer therapies.

Abstract

Argonaute proteins (AGOs) play crucial roles in RNA-induced silencing complex (RISC) formation and activity. AGOs loaded with small RNA molecules (miRNA or siRNA) either catalyze endoribonucleolytic cleavage of target RNAs or recruit factors responsible for translational silencing and target destabilization. miRNAs are well characterized and broadly studied in tumorigenesis; nevertheless, the functions of the AGOs in cancers have lagged behind. Here, we discuss the current state of knowledge on the role of AGOs in tumorigenesis, highlighting canonical and non-canonical functions of AGOs in cancer cells, as well as the biomarker potential of AGO expression in different of tumor types. Furthermore, we point to the possible application of the AGOs in development of novel therapeutic approaches.

The GSK3β-β-catenin-TCF1 pathway improves naive T cell activation in old adults by upregulating miR-181a

MicroRNAs play an important role in the regulation of T cell development, activation, and differentiation. One of the most abundant microRNAs in lymphocytes is miR-181a, which controls T cell receptor (TCR) activation thresholds in thymic selection as well as in peripheral T cell responses. We previously found that miR-181a levels decline in T cells in the elderly. In this study, we identified TCF1 as a transcriptional regulator of pri-miR-181a. A decline in TCF1 levels in old individuals accounted for the reduced miR-181a expression impairing TCR signaling. Inhibition of GSK3ß restored expression of miR-181a by inducing TCF1 in T cells from old adults. GSK3ß inhibition enhanced TCR signaling to increase downstream expression of activation markers and production of IL-2. The effect involved the upregulation of miR-181a and the inhibition of DUSP6 expression. Thus, inhibition of GSK3ß can restore responses of old T cells by inducing miR-181a expression through TCF1.

Bringing MicroRNAs to Light: Methods for MicroRNA Quantification and Visualization in Live Cells

MiRNAs are small non-coding RNAs that interact with their target mRNAs for posttranscriptional gene regulation. Finely controlled miRNA biogenesis, target recognition and degradation indicate that maintaining miRNA homeostasis is essential for regulating cell proliferation, growth, differentiation and apoptosis. Increasingly, miRNAs have been recognized as a potential biomarker for disease diagnosis. MiRNAs can be found in blood, plasma, and tissues, and miRNA expression and activity differ in developmental stages, tissues and in response to external stimuli. MiRNA transcripts are matured from pri-miRNA over pre-miRNA to mature miRNA, a process that includes multiple steps and enzymes. Many tools are available to identify and quantify specific miRNAs, ranging from measuring total miRNA, specific miRNA activity, miRNA arrays and miRNA localization. The various miRNA assays differ in accuracy, cost, efficiency and convenience of monitoring miRNA dynamics. To acknowledge the significance and increasing research interest in miRNAs, we summarize the traditional as well as novel methods of miRNA quantification with strengths and limitations of various techniques in biochemical and medical research.

microRNAs Biogenesis, Functions and Role in Tumor Angiogenesis

microRNAs (miRNAs) are small non-coding RNA molecules, evolutionary conserved. They target more than one mRNAs, thus influencing multiple molecular pathways, but also mRNAs may bind to a variety of miRNAs, either simultaneously or in a context-dependent manner. miRNAs biogenesis, including miRNA transcription, processing by Drosha and Dicer, transportation, RISC biding, and miRNA decay, are finely controlled in space and time. miRNAs are critical regulators in various biological processes, such as differentiation, proliferation, apoptosis, and development in both health and disease. Their dysregulation is involved in tumor initiation and progression. In tumors, they can act as onco-miRNAs or oncosuppressor-miRNA participating in distinct cellular pathways, and the same miRNA can perform both activities depending on the context. In tumor progression, the angiogenic switch is fundamental. miRNAs derived from tumor cells, endothelial cells, and cells of the surrounding microenvironment regulate tumor angiogenesis, acting as pro-angiomiR or anti-angiomiR. In this review, we described miRNA biogenesis and function, and we update the non-classical aspects of them. The most recent role in the nucleus, as transcriptional gene regulators and the different mechanisms by which they could be dysregulated, in tumor initiation and progression, are treated. In particular, we describe the role of miRNAs in sprouting angiogenesis, vessel co-option, and vasculogenic mimicry. The role of miRNAs in lymphoma angiogenesis is also discussed despite the scarcity of data. The information presented in this review reveals the need to do much more to discover the complete miRNA network regulating angiogenesis, not only using high-throughput computational analysis approaches but also morphological ones.

Expression of microRNA-181a and microRNA-196b in Egyptian Pediatric acute Lymphoblastic Leukemia

Background:

Differential expression of miRNA provides important insights into pathogenesis of cancer including leukemia. Deregulation of microRNA may contribute to hematopoietic malignancies. In this study, we aimed to evaluate the role of miR-181a and miR-196b in acute lymphoblastic leukemia (ALL) and correlate their expression with clinical and laboratory data.

Methods:

The study was performed on bone marrow samples of 70 consecutive newly diagnosed pediatric (ALL) patients, of which 56 were evaluated for both miR-181a and miR-196b (all 70 for miR-181a) by real-time quantitative reverse transcriptase polymerase chain reaction (RT-qPCR). In addition, bone marrow from seven age and sex matched healthy controls derived from donors of bone marrow transplantation were assessed.

Results:

miR-181a expression was significantly up-regulated in ALL patients compared with healthy controls (p<0.001). However, miR-196b expression was significantly down-regulated in patients compared with healthy controls (p=0.038).

Conclusion:

Our results suggest that miR-181a has an oncogenic, while miR-196b has a tumor suppressive role in pediatric ALL patients. A finding which demonstrate the potential role of these microRNAs in pathogenesis of pediatric ALL. Also, estimation of their expression level may provide a tool for confirmation of a diagnosis of childhood ALL and could be a possible predictor of early relapse.

MiR-1696/GPx3 axis is involved in oxidative stress mediated neutrophil extracellular traps inhibition in chicken neutrophils

As an important immune mechanism of neutrophils, the release of Web-like chromatin structures known as neutrophil extracellular traps (NETs) can rapidly locate and capture invading pathogens, which has received sustained attention. There are still some fundamental questions surrounding established studies on the mechanism of balance between reactive oxygen species (ROS) dependent release and neutrophil antioxidant response. Glutathione peroxidase 3 (GPx3) is an important antioxidant protein and has been identified can regulate the immune response. However, the effect of GPx3 on the NETs formation and microRNA in this process remain poorly understood. In the present study, we used chicken peripheral blood neutrophils treated with Phorbol-12-myristate-13-acetate (PMA) for 3 h as NETs formation model. The result of morphological observation showed that GPx3 inactivation compromised the release of NETs. Further analysis revealed that knockdown of GPx3 significantly disturbed oxidative balance by inhibiting antioxidant enzymes activity and increasing H₂ O₂ content. Quantitative analysis of NETs-related genes found that the phosphorylation level of mitogen-activated protein kinase (MAPK) pathway genes (ERK, JNK, and p38) and expression of phosphoinositide-3-kinase (PI3K)/AKT pathway genes (PI3K and AKT) were suppressed with the downregulation of GPx3. Meanwhile, we identified that miR-1696 can target GPx3 expression by using dual luciferase reporter system. Additionally, overexpression of miR-1696 can not only inhibit the formation of NETs by restraining the expression of GPx3, interfering with the generation of ROS and activation of the MAPK and PI3K/AKT pathways, but also reducing the release of PMA-induced NETs promoted by overexpression of GPx3. These results provide evidence that miR-1696 targeted GPx3 activities in neutrophils could be used to regulate the NETs formation stimulated by PMA.

MicroRNA-Independent Modulation of DICER1 Expression by hAgo2

Many proteins, including DICER1 and hAgo2, are involved in the biogenesis of microRNAs (miRNAs). Whether hAgo2 regulates DICER1 expression is unknown. Exogenously overexpressed hAgo2 suppressed DICER1 expression at the levels of both protein and mRNA, and the reduction in hAgo2 expression enhanced DICER1 expression. Precursor miRNA processing mediated by DICER1 was also modulated by hAgo2. However, hAgo2 protein did not suppress DICER1 promoter activity. Therefore, hAgo2 protein probably regulates DICER1 expression at the posttranscriptional level. Indeed, hAgo2 protein inhibited the reporter assay of the DICER1 mRNA 3' untranslated region (3'-UTR). Previous reports have demonstrated that miRNAs (e.g., let-7 and miR-103/107) inhibited DICER1 expression posttranscriptionally. However, hAgo2 still suppressed DICER1 expression in the cells depleted of these miRNAs. Moreover, the reporter activities of the DICER1 mRNA 3'-UTR without these miRNA binding sites were still suppressed by hAgo2. Therefore, in addition to an miRNA-dependent pathway, hAgo2 can also modulate DICER1 expression through an miRNA-independent mechanism. Downregulation of DICER1 expression was further proven to be dependent on both hAgo2 and AUF1 proteins. Interactions of hAgo2 and AUF1 proteins were demonstrated by the coimmunoprecipitation assay. As expected, hAgo2 could not suppress the DICER1 mRNA 3'-UTR reporter with a mutation in the potential AUF1-binding site. Thus, downregulation of DICER1 expression through the 3'-UTR requires both hAgo2 and AUF1.

The Role of MicroRNAs in Development and Function of Regulatory T Cells - Lessons for a Better Understanding of MicroRNA Biology

MicroRNAs (miRNAs) have emerged as critical posttranscriptional regulators of the immune system, including function and development of regulatory T (Treg) cells. Although this critical role has been firmly demonstrated through genetic models, key mechanisms of miRNA function in vivo remain elusive. Here, we review the role of miRNAs in Treg cell development and function. In particular, we focus on the question what the study of miRNAs in this context reveals about miRNA biology in general, including context-dependent function and the role of individual targets vs. complex co-targeting networks. In addition, we highlight potential technical pitfalls and state-of-the-art approaches to improve the mechanistic understanding of miRNA biology in a physiological context.

Characterization of the regulation mechanism of grapevine microRNA172 family members during flower development

BACKGROUND

Grapevine (Vitis vinifera L.), which has important nutritional values and health benefits, is one of the most economically important fruit crops cultivated worldwide. Several studies showed a large number of microRNAs (VvmiRNAs) involved in the modulation of grape growth and development, and many VvmiRNA families have multiple members. However, the way by which various members from the same miRNA family work is unclear, particularly in grapes.

RESULTS

In this study, an important conserved VvmiR172 family (VvmiR172s) and their targets were set as a good example for elucidating the interaction degree, mechanism, and spatio-temporal traits of diverse members from the same miRNA family. miR-RACE and Stem-loop RT-PCR were used to identify the spatio-temporal expressions of various members of VvmiR172s; together with RLM-RACE, PPM-RACE, Western blot, transgenic technologies, their interaction degree, and regulation mechanism were further validated. The expression of VvmiR172c was significantly higher than that of VvmiR172a, b, and d and showed a positive correlation with the abundance of VvAP2 cleavage products. These findings indicated that VvmiR172c might be one of the main action factors of the VvmiR172 family in flower development. The ability of VvmiR172c to cleave target genes differed due to divergence in complementary degree with VvAP2 and expression levels of various members. In VvmiR172 transgenic lines, we observed that 35S::VvmiR172c resulted in the earliest and abundant flowering, indicating the strong function of VvmiR172c. In contrast, the non-significant phenotypic changes were detected in the VvAP2 transgenic lines. The qRT-PCR and Western bolt results demonstrated that VvmiR172c plays a major role in targeting VvAP2.

CONCLUSIONS

VvmiR172 up-regulated the expression of NtFT and decreased the expression of NtFLC. The up/down regulation of VvmiR172c was the most pronounced. The functions of four VvmiR172 members in grape differed, and miR172c had the strongest regulation on AP2.

MicroRNA miR-181-A Rheostat for TCR Signaling in Thymic Selection and Peripheral T-Cell Function

The selection of T cells during intra-thymic d evelopment is crucial to obtain a functional and simultaneously not self-reactive peripheral T cell repertoire. However, selection is a complex process dependent on T cell receptor (TCR) thresholds that remain incompletely understood. In peripheral T cells, activation, clonal expansion, and contraction of the active T cell pool, as well as other processes depend on TCR signal strength. Members of the microRNA (miRNA) miR-181 family have been shown to be dynamically regulated during T cell development as well as dependent on the activation stage of T cells. Indeed, it has been shown that expression of miR-181a leads to the downregulation of multiple phosphatases, implicating miR-181a as ‘‘rheostat’’ of TCR signaling. Consistently, genetic models have revealed an essential role of miR-181a/b-1 for the generation of unconventional T cells as well as a function in tuning TCR sensitivity in peripheral T cells during aging. Here, we review these broad roles of miR-181 family members in T cell function via modulating TCR signal strength.

Emerging Roles for Noncoding RNAs in Autoimmune Thyroid Disease

Autoimmune thyroid disease (AITD) is one of the most frequent autoimmune disorders. However, the pathogenesis of AITD has not been fully elucidated. Recently, accumulating evidence has demonstrated that abnormal expression of noncoding RNAs (ncRNAs) is closely related to the etiopathogenesis of AITD. microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) are 3 major groups of ncRNAs that are attracting increasing attention. Herein, we summarized our present knowledge on the role of miRNAs, lncRNAs, and circRNAs in AITD. This review focused on the importance of ncRNAs in development of the most prevalent AITD, such as Hashimoto disease and Graves' diseases. Altogether, the main purpose of this review is to provide new insights in the pathogenesis of AITD and the possibility of developing novel potential therapeutic targets.

Role of miRNAs in Normal and Myasthenia Gravis Thymus

The thymus, a primary lymphoid organ, provides a complex environment essential for the generation of the T-cell repertoire. Thymic alterations occur during life either in the context of thymic involution upon aging or the pathophysiological context of Myasthenia Gravis (MG). These changes involve complicated regulatory networks, in which microRNAs (miRNAs) are key players. Here, we analyzed the role of miRNAs in thymocyte maturation and differentiation sustained by thymic epithelial cells. We compared data from the literature regarding the role of mouse thymic miRNAs and original data obtained from a human thymic miRnome study. We identified a set of highly expressed miRNAs defined as ThymiRs and investigated miRNA expression in infants as compared to adults to determine those associated with human thymic involution. Thymic changes are also frequently observed in MG, an autoimmune disease which results in the production of anti-acetylcholine receptor (AChR) antibodies that lead to muscle weaknesses. Alterations such as thymoma in late-onset MG patients and hyperplasia with ectopic germinal centers (GCs) in early-onset (EOMG) patients are found. Thymic miRNA expression has been studied in AChR-MG patients both in thymoma-associated MG (TAMG) and EOMG, and their function through their mRNA targets investigated. Most of the dysregulated thymic miRNAs in EOMG are associated with GC development, such as miR-7, miR-24, miR-139, miR-143, miR-145, miR-146, miR-150, miR-452, miR-548 or thymic inflammation, such as miR-125b, miR-146, or miR-29. Understanding these pathways may provide therapeutic targets or biomarkers of disease manifestations.

miR-155 indicates the fate of CD4+ T cells

MicroRNAs (miRNAs) are a class of short noncoding RNAs that regulate the translation of target messenger RNA (mRNA) and consequently participate in a variety of biological processes at the posttranscriptional level. miR-155, encoded within a region known as the B cell integration cluster (BIC), plays multifunctional roles in shaping lymphocytes ranging from biological development to adaptive immunity. It has been revealed that miR-155 plays a key role in fine-tuning the regulation of lymphocyte subsets, including dendritic cells (DCs), macrophages, B cells, and CD8⁺ and CD4⁺ T cells. Antigen-specific CD4⁺ T lymphocytes are critical for host defense against pathogens and prevention of damage resulting from excessive inflammation. Over the past years, various studies have shown that miR-155 plays a critical role in CD4⁺ T cells function. Therefore, we summarize multiple target genes of miR-155 that regulate aspects of CD4⁺ T cells immunity, particularly CD4⁺ T cells differentiation, in this review. In addition, we also focus on the role of miR-155 in the regulation of immunological diseases, suggesting it as a potential disease biomarker and therapeutic target.