MicroRNA fingerprints during human megakaryocytopoiesis

miR-1915-3p regulates megakaryocytic and erythroid differentiation by targeting SOCS4

BACKGROUND

Proper control of the lineage bias of megakaryocytic and erythroid progenitor cells (MEPs) is of significant importance, the disorder of which will lead to abnormalities in the number and function of platelets and erythrocytes. Unfortunately, the signaling pathways regulating MEP differentiation largely remain to be elucidated. This study aimed to analyze the role and the underlying molecular mechanism of miR-1915-3p in megakaryocytic and erythroid differentiation.

METHODS

We utilized miRNA mimics and miRNA sponge to alter the expression of miR-1915-3p in megakaryocytic and/or erythroid potential cells; siRNA and overexpression plasmid to change the expression of SOCS4, a potential target of miR-1915-3p. The expression of relevant surface markers was detected by flow cytometry. We scanned for miR-1915-3p target genes by mRNA expression profiling and bioinformatic analysis, and confirmed the targeting by dual-luciferase reporter assay, western blot and gain- and lost-of-function studies. One-way ANOVA and t-test were used to analyze the statistical significance.

RESULTS

In this study, overexpression or knockdown of miR-1915-3p inhibited or promoted erythroid differentiation, respectively. Accordingly, we scanned for miR-1915-3p target genes and confirmed that SOCS4 is one of the direct targets of miR-1915-3p. An attentive examination of the endogenous expression of SOCS4 during megakaryocytic and erythroid differentiation suggested the involvement of SOCS4 in erythroid/megakaryocytic lineage determination. SOCS4 knockdown lessened erythroid surface markers expression, as well as improved megakaryocytic differentiation, similar to the effects of miR-1915-3p overexpression. While SOCS4 overexpression resulted in reversed effects. SOCS4 overexpression in miR-1915-3p upregulated cells rescued the effect of miR-1915-3p.

CONCLUSIONS

miR-1915-3p acts as a negative regulator of erythropoiesis, and positively in thrombopoiesis. SOCS4 is one of the key mediators of miR-1915-3p during the differentiation of MEPs.

Distinct serum exosomal miRNA profiles detected in acute and asymptomatic dengue infections: A community-based study in Baiyun District, Guangzhou

Background

In recent years, research on exosomal miRNAs has provided new insights into exploring the mechanism of viral infection and disease prevention. This study aimed to investigate the serum exosomal miRNA expression profile of dengue-infected individuals through a community survey of dengue virus (DENV) infection.

Methods

A seroprevalence study of 1253 healthy persons was first conducted to ascertain the DENV infection status in Baiyun District, Guangzhou. A total of 18 serum samples, including 6 healthy controls (HC), 6 asymptomatic DENV infections (AsymptDI), and 6 confirmed dengue fever patients (AcuteDI), were collected for exosome isolation and then sRNA sequencing. Through bioinformatics analysis, we discovered distinct serum exosomal miRNA profiles among the different groups and identified differentially expressed miRNAs (DEMs). These findings were further validated by qRT-PCR.

Results

The community survey of DENV infection indicated that the DENV IgG antibody positivity rate among the population was 11.97 % in the study area, with asymptomatic infected individuals accounting for 93.06 % of the anti-DENV IgG positives. The age and Guangzhou household registration were associated with DENV IgG antibody positivity by logistic regression analysis. Distinct miRNA profiles were observed between healthy individuals and DENV infections. A total of 1854 miRNAs were identified in 18 serum exosome samples from the initial analysis of the sequencing data. Comparative analysis revealed 23 DEMs comprising 5 upregulated and 18 downregulated miRNAs in the DENV-infected group (mergedDI). In comparison to AcuteDI, 18 upregulated miRNAs were identified in AsymptDI. Moreover, functional enrichment of the predicted target genes of DEMs indicated that these miRNAs were involved in biological processes and pathways related to cell adhesion, focal adhesion, endocytosis, and ECM-receptor interaction. Eight DEMs were validated by qRT-PCR.

Conclusion

The Baiyun District of Guangzhou exhibits a notable proportion of asymptomatic DENV infections as suggested in other research, highlighting the need for enhanced monitoring and screening of asymptomatic persons and the elderly. Differential miRNA expression among healthy, symptomatic and asymptomatic DENV-infected individuals suggests their potential as biomarkers for distinguishing DENV infection and offers new avenues of investigating the mechanisms underlying DENV asymptomatic infections.

Transcription Factor TAL1 in Erythropoiesis

Lineage-specific transcription factors (TFs) regulate differentiation of hematopoietic stem cells (HSCs). They are decisive for the establishment and maintenance of lineage-specific gene expression programs during hematopoiesis. For this they create a regulatory network between TFs, epigenetic cofactors, and microRNAs. They activate cell-type specific genes and repress competing gene expression programs. Disturbance of this process leads to impaired lineage fidelity and diseases of the blood system. The TF T-cell acute leukemia 1 (TAL1) is central for erythroid differentiation and contributes to the formation of distinct gene regulatory complexes in progenitor cells and erythroid cells. A TAL1/E47 heterodimer binds to DNA with the TFs GATA-binding factor 1 and 2 (GATA1/2), the cofactors LIM domain only 1 and 2 (LMO1/2), and LIM domain-binding protein 1 (LDB1) to form a core TAL1 complex. Furthermore, cell-type-dependent interactions of TAL1 with other TFs such as with runt-related transcription factor 1 (RUNX1) and Kruppel-like factor 1 (KLF1) are established. Moreover, TAL1 activity is regulated by the formation of TAL1 isoforms, posttranslational modifications (PTMs), and microRNAs. Here, we describe the function of TAL1 in normal hematopoiesis with a focus on erythropoiesis.

Roles of non-coding RNA in megakaryocytopoiesis and thrombopoiesis: new target therapies in ITP

Noncoding RNAs (ncRNAs) are a group of RNA molecules that cannot encode proteins, and a better understanding of the complex interaction networks coordinated by ncRNAs will provide a theoretical basis for the development of therapeutics targeting the regulatory effects of ncRNAs. Platelets are produced upon the differentiation of hematopoietic stem cells into megakaryocytes, 10¹¹ per day, and are renewed every 8-9 days. The process of thrombopoiesis is affected by multiple factors, in which ncRNAs also exert a significant regulatory role. This article reviewed the regulatory roles of ncRNAs, mainly microRNAs (miRNAs), circRNAs (circular RNAs), and long non-coding RNAs (lncRNAs), in thrombopoiesis in recent years as well as their roles in primary immune thrombocytopenia (ITP).

Insight into microRNAs' involvement in hematopoiesis: current standing point of findings

Hematopoiesis is a complex process in which hematopoietic stem cells are differentiated into all mature blood cells (red blood cells, white blood cells, and platelets). Different microRNAs (miRNAs) involve in several steps of this process. Indeed, miRNAs are small single-stranded non-coding RNA molecules, which control gene expression by translational inhibition and mRNA destabilization. Previous studies have revealed that increased or decreased expression of some of these miRNAs by targeting several proto-oncogenes could inhibit or stimulate the myeloid and erythroid lineage commitment, proliferation, and differentiation. During the last decades, the development of molecular and bioinformatics techniques has led to a comprehensive understanding of the role of various miRNAs in hematopoiesis. The critical roles of miRNAs in cell processes such as the cell cycle, apoptosis, and differentiation have been confirmed as well. However, the main contribution of some miRNAs is still unclear. Therefore, it seems undeniable that future studies are required to focus on miRNA activities during various hematopoietic stages and hematological malignancy.

Dietary ketone body-escalated histone acetylation in megakaryocytes alleviates chemotherapy-induced thrombocytopenia

Chemotherapy-induced thrombocytopenia (CIT) is a severe complication in patients with cancer that can lead to impaired therapeutic outcome and survival. Clinically, therapeutic options for CIT are limited by severe adverse effects and high economic burdens. Here, we demonstrate that ketogenic diets alleviate CIT in both animals and humans without causing thrombocytosis. Mechanistically, ketogenic diet-induced circulating β-hydroxybutyrate (β-OHB) increased histone H3 acetylation in bone marrow megakaryocytes. Gain- and loss-of-function experiments revealed a distinct role of 3-β-hydroxybutyrate dehydrogenase (BDH)-mediated ketone body metabolism in promoting histone acetylation, which promoted the transcription of platelet biogenesis genes and induced thrombocytopoiesis. Genetic depletion of the megakaryocyte-specific ketone body transporter monocarboxylate transporter 1 (MCT1) or pharmacological targeting of MCT1 blocked β-OHB-induced thrombocytopoiesis in mice. A ketogenesis-promoting diet alleviated CIT in mouse models. Moreover, a ketogenic diet modestly increased platelet counts without causing thrombocytosis in healthy volunteers, and a ketogenic lifestyle inversely correlated with CIT in patients with cancer. Together, we provide mechanistic insights into a ketone body-MCT1-BDH-histone acetylation-platelet biogenesis axis in megakaryocytes and propose a nontoxic, low-cost dietary intervention for combating CIT.

Insights Into Platelet-Derived MicroRNAs in Cardiovascular and Oncologic Diseases: Potential Predictor and Therapeutic Target

Non-communicable diseases (NCDs), represented by cardiovascular diseases and cancer, have been the leading cause of death globally. Improvements in mortality from cardiovascular (CV) diseases (decrease of 14%/100,000, United States) or cancers (increase 7.5%/100,000, United States) seem unsatisfactory during the past two decades, and so the search for innovative and accurate biomarkers of early diagnosis and prevention, and novel treatment strategies is a valuable clinical and economic endeavor. Both tumors and cardiovascular system are rich in angiological systems that maintain material exchange, signal transduction and distant regulation. This pattern determines that they are strongly influenced by circulating substances, such as glycolipid metabolism, inflammatory homeostasis and cyclic non-coding RNA and so forth. Platelets, a group of small anucleated cells, inherit many mature proteins, mRNAs, and non-coding RNAs from their parent megakaryocytes during gradual formation and manifest important roles in inflammation, angiogenesis, atherosclerosis, stroke, myocardial infarction, diabetes, cancer, and many other diseases apart from its classical function in hemostasis. MicroRNAs (miRNAs) are a class of non-coding RNAs containing ∼22 nucleotides that participate in many key cellular processes by pairing with mRNAs at partially complementary binding sites for post-transcriptional regulation of gene expression. Platelets contain fully functional miRNA processors in their microvesicles and are able to transport their miRNAs to neighboring cells and regulate their gene expression. Therefore, the importance of platelet-derived miRNAs for the human health is of increasing interest. Here, we will elaborate systematically the roles of platelet-derived miRNAs in cardiovascular disease and cancer in the hope of providing clinicians with new ideas for early diagnosis and therapeutic strategies.

HOXA1, a breast cancer oncogene

More than 25 years ago, the first literature records mentioned HOXA1 expression in human breast cancer. A few years later, HOXA1 was confirmed as a proper oncogene in mammary tissue. In the following two decades, molecular data about the mode of action of the HOXA1 protein, the factors contributing to activate and maintain HOXA1 gene expression and the identity of its target genes have accumulated and provide a wider view on the association of this transcription factor to breast oncogenesis. Large-scale transcriptomic data gathered from wide cohorts of patients further allowed refining the relationship between breast cancer type and HOXA1 expression. Several recent reports have reviewed the connection between cancer hallmarks and the biology of HOX genes in general. Here we take HOXA1 as a paradigm and propose an extensive overview of the molecular data centered on this oncoprotein, from what its expression modulators, to the interactors contributing to its oncogenic activities, and to the pathways and genes it controls. The data converge to an intricate picture that answers questions on the multi-modality of its oncogene activities, point towards better understanding of breast cancer aetiology and thereby provides an appraisal for treatment opportunities.

Differential expression of microRNA between triple negative breast cancer patients of African American and European American descent

There are racial disparities in the outcome of triple negative breast cancer (TNBC) patients between women of African ancestry and women of European ancestry, even after accounting for lifestyle, socioeconomic and clinical factors. MicroRNA (miRNA) are non-coding molecules whose level of expression is associated with cancer suppression, proliferation and drug resistance; therefore, these have potential for biomarker applications in cancers including TNBC. Historically, miRNAs up-regulated in African American (AA) patients have received less attention than for patients of European ancestry. Using laser capture microdissection (LCM) to acquire ultrapure tumor cell samples, miRNA expression was evaluated in 15 AA and 15 European American (EA) TNBC patients. Tumor sections were evaluated using RNA extraction followed by miRNA analysis and profiling. Results were compared based on ethnicity and method of tissue fixation. miRNAs that showed high differential expression in AA TNBC patients compared to EA included: miR-19a, miR-192, miR-302a, miR-302b, miR-302c, miR-335, miR-520b, miR-520f and miR-645. LCM is a useful technique for isolation of tumor cells. We found a greater abundance of RNA in frozen samples compared to formalin fixed, paraffin embedded samples. miRNA appears to be a useful biomarker for TNBC to improve diagnosis and treatment.

A coordinated function of lncRNA HOTTIP and miRNA-196b underpinning leukemogenesis by targeting FAS signaling

MicroRNAs (miRNAs) may modulate more than 60% of human coding genes and act as negative regulators, whereas long noncoding RNAs (lncRNAs) regulate gene expression on multiple levels by interacting with chromatin, functional proteins, and RNAs such as mRNAs and microRNAs. However, the crosstalk between HOTTIP lncRNA and miRNAs in leukemogenesis remains elusive. Using combined integrated analyses of global miRNA expression profiling and state-of-the-art genomic analyses of chromatin such as ChIRP-seq (HOTTIP binding in genomewide), ChIP-seq, and ATAC-seq, we found that some miRNA genes are directly controlled by HOTTIP. Specifically, the HOX cluster miRNAs (miR-196a, miR-196b, miR-10a, and miR-10b), located cis and trans, were most dramatically regulated and significantly decreased in HOTTIP-/- AML cells. HOTTIP bound to the miR-196b promoter and HOTTIP deletion reduced chromatin accessibility and enrichment of active histone modifications at HOX cluster-associated miRNAs in AML cells, whereas reactivation of HOTTIP restored miR gene expression and chromatin accessibility in the CTCF-boundary-attenuated AML cells. Inactivation of HOTTIP or miR-196b promotes apoptosis by altering the chromatin signature at the FAS promoter and increasing FAS expression. Transplantation of miR-196b knockdown MOLM13 cells in NSG mice increased overall survival of mice compared to wild-type cells transplanted into mice. Thus, HOTTIP remodels the chromatin architecture around miRNAs to promote their transcription and consequently represses tumor suppressors and promotes leukemogenesis.

The MPL mutation

Myeloproliferative neoplasms (MPN) patients share driver mutations in JAK2, MPL or CALR genes leading to the activation of the thrombopoietin receptor (TPOR) and downstream signaling pathways. JAK2 mutation drives all the three major entities of MPN (Polycythemia Vera, Essential Thrombocythemia and Primary Myelofibrosis) through the constitutive activation of TPOR, erythropoietin (EPOR) and colony stimulating factor 3 receptor (CSF3R) signaling. MPL is a proto-oncogene encoding for TPOR, the hematopoietic growth factor receptor of myeloid stem cells. MPL mutants induce the stable dimerization of TPOR that in turn activate JAK2 and the thrombopoietin pathway. The thrombopoietin pathway plays an important role in the development of megakaryocytes and platelets as well as the self-renewal of hematopoietic stem cells. Little wonder therefore that mutations of MPL result in thrombocytosis, leading to an abnormal MPL trafficking or receptor activation. Finally, some extremely rare germline genetic variants in MPL can induce MPN-like hereditary disease. Against this molecular background, TPOR is a key actor in the MPN development and MPL mutations are of major relevance to fully elucidate the molecular mechanisms underlying the clinical manifestations of MPN and to arrange novel therapeutic strategies aiming to disrupt the dysegulated signaling cascade. This chapter will focus on the role MPL in the pathogenesis of MPN and in familial thrombocytosis and will review these different subtypes of somatic and germline genetic variants by dissecting how they impact clinical phenotype.

MicroRNAs as Biomarkers for Early Diagnosis, Prognosis, and Therapeutic Targeting of Ovarian Cancer

Ovarian cancer is the major cause of gynecologic cancer-related mortality. Regardless of outstanding advances, which have been made for improving the prognosis, diagnosis, and treatment of ovarian cancer, the majority of the patients will die of the disease. Late-stage diagnosis and the occurrence of recurrent cancer after treatment are the most important causes of the high mortality rate observed in ovarian cancer patients. Unraveling the molecular mechanisms involved in the pathogenesis of ovarian cancer may help find new biomarkers and therapeutic targets for ovarian cancer. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression, mostly at the posttranscriptional stage, through binding to mRNA targets and inducing translational repression or degradation of target via the RNA-induced silencing complex. Over the last two decades, the role of miRNAs in the pathogenesis of various human cancers, including ovarian cancer, has been documented in multiple studies. Consequently, these small RNAs could be considered as reliable markers for prognosis and early diagnosis. Furthermore, given the function of miRNAs in various cellular pathways, including cell survival and differentiation, targeting miRNAs could be an interesting approach for the treatment of human cancers. Here, we review our current understanding of the most updated role of the important dysregulation of miRNAs and their roles in the progression and metastasis of ovarian cancer. Furthermore, we meticulously discuss the significance of miRNAs as prognostic and diagnostic markers. Lastly, we mention the opportunities and the efforts made for targeting ovarian cancer through inhibition and/or stimulation of the miRNAs.

The Role of miRNAs as Therapeutic Tools in Sickle Cell Disease

Background and Objectives: Sickle cell disorder (SCD) is a paradigmatic example of a complex monogenic disorder. SCD is characterized by the production of abnormal hemoglobin, primarily in the deoxygenated state, which makes erythrocytes susceptible to intracellular hemoglobin polymerization. Functional studies have affirmed that the dysregulation of miRNAs enhances clinical severity or has an ameliorating effect in SCD. miRNAs can be effectively regulated to reduce the pace of cell cycle progression, to reduce iron levels, to influence hemolysis and oxidative stress, and most importantly, to increase γ-globin gene expression and enhance the effectiveness of hydroxyurea. Results: This review highlights the roles played by some key miRNAs in hemoglobinopathies, especially in hematopoiesis, erythroid differentiation, and severity of anemia, which make miRNAs attractive molecular tools for innovative therapeutic approaches. Conclusions: In this era of targeted medicine, miRNAs mimics and antagomirs may be promising inducers of HbF synthesis which could ameliorate the clinical severity of SCD.

Rapid, multiplexed detection of the let-7 miRNA family using γPNA amphiphiles in micelle-tagging electrophoresis

miRNA is a promising class of biomarkers whose levels can be assayed to detect various forms of cancer and other serious diseases. These short, noncoding nucleic acids are difficult to detect due to their low abundance and the marginal stability of their duplexes with DNA probes. In addition, miRNAs within the same family have high sequence homology, and often, related miRNA differ in sequence by only a single base. In this report, we demonstrate an independent detection seven members of the let-7 family of miRNA in a single run. Key to success is the use of mini-PEG-substituted PNA amphiphiles (γPNAA) and highly fluorescent DNA nanotags in micelle tagging electrophoresis (MTE). Multiplexed detection is accomplished in capillary electrophoresis (CE) using oligomeric nanotags of pre-programmed lengths where the presence of a specific miRNA links its nanotag to a micelle drag-tag, which shifts the nanotag elution time to a defined region for detection. We further demonstrate that the peak shape and elution time are unaffected by the presence of up to 10 mg/ml of serum protein in the sample, with a total runtime of less than 4 min and a LOD of 10-100 pM. We discuss efforts to substantially decrease the detection limit using nanotags that are >1000 bp in length.

Multisite Evaluation of Next-Generation Methods for Small RNA Quantification

Small RNAs (smRNAs) are important regulators of many biologic processes and are now most frequently characterized using Illumina sequencing. However, although standard RNA sequencing library preparation has become routine in most sequencing facilities, smRNA sequencing library preparation has historically been challenging because of high input requirements, laborious protocols involving gel purifications, inability to automate, and a lack of benchmarking standards. Additionally, studies have suggested that many of these methods are nonlinear and do not accurately reflect the amounts of smRNAs in vivo. Recently, a number of new kits have become available that permit lower input amounts and less laborious, gel-free protocol options. Several of these new kits claim to reduce RNA ligase-dependent sequence bias through novel adapter modifications and to lessen adapter-dimer contamination in the resulting libraries. With the increasing number of smRNA kits available, understanding the relative strengths of each method is crucial for appropriate experimental design. In this study, we systematically compared 9 commercially available smRNA library preparation kits as well as NanoString probe hybridization across multiple study sites. Although several of the new methodologies do reduce the amount of artificially over- and underrepresented microRNAs (miRNAs), we observed that none of the methods was able to remove all of the bias in the library preparation. Identical samples prepared with different methods show highly varied levels of different miRNAs. Even so, many methods excelled in ease of use, lower input requirement, fraction of usable reads, and reproducibility across sites. These differences may help users select the most appropriate methods for their specific question of interest.

The Landscape of Coding and Noncoding RNAs in Platelets

Significance: Levels of platelet noncoding RNAs (ncRNAs) are altered by disease, and ncRNAs may exert functions inside and outside of platelets. Their role in physiologic hemostasis and pathologic thrombosis remains to be explored. Recent Advances: The number of RNA classes identified in platelets has been growing since the past decade. Apart from coding messenger RNAs, the RNA landscape in platelets comprises ncRNAs such as microRNAs, circular RNAs, long ncRNAs, YRNAs, and potentially environmentally derived exogenous ncRNAs. Recent research has focused on the function of platelet RNAs beyond platelets, mediated through protective RNA shuttles or even cellular uptake of entire platelets. Multiple studies have also explored the potential of platelet RNAs as novel biomarkers. Critical Issues: Platelet preparations can contain contaminating leukocytes. Even few leukocytes may contribute a substantial amount of RNA. As biomarkers, platelet RNAs have shown associations with platelet activation, but it remains to be seen whether their measurements could improve diagnostics. It also needs to be clarified whether platelet RNAs influence processes beyond platelets. Future Directions: Technological advances such as single-cell RNA-sequencing might help to identify hyperreactive platelet subpopulations on a single-platelet level, avoid the common problem of leukocyte contamination in platelet preparations, and allow simultaneous profiling of native megakaryocytes and their platelet progeny to clarify to what extent the platelet RNA content reflects their megakaryocyte precursors or changes in the circulation. Antioxid. Redox Signal. 34, 1200-1216.

Atrial myxomas arise from multipotent cardiac stem cells

Aims

Cardiac myxomas usually develop in the atria and consist of an acid-mucopolysaccharide-rich myxoid matrix with polygonal stromal cells scattered throughout. These human benign tumours are a valuable research model because of the rarity of cardiac tumours, their clinical presentation and uncertain origin. Here, we assessed whether multipotent cardiac stem/progenitor cells (CSCs) give rise to atrial myxoma tissue.

Methods and results

Twenty-three myxomas were collected and analysed for the presence of multipotent CSCs. We detected myxoma cells positive for c-kit (c-kit^pos) but very rare Isl-1 positive cells. Most of the c-kit^pos cells were blood lineage-committed CD45^pos/CD31^pos cells. However, c-kit^pos/CD45^neg/CD31^neg cardiac myxoma cells expressed stemness and cardiac progenitor cell transcription factors. Approximately ≤10% of the c-kit^pos/CD45^neg/CD31^neg myxoma cells also expressed calretinin, a characteristic of myxoma stromal cells. In vitro, the c-kit^pos/CD45^neg/CD31^neg myxoma cells secrete chondroitin-6-sulfate and hyaluronic acid, which are the main components of gelatinous myxoma matrix in vivo. In vitro, c-kit^pos/CD45^neg/CD31^neg myxoma cells have stem cell properties being clonogenic, self-renewing, and sphere forming while exhibiting an abortive cardiac differentiation potential. Myxoma-derived CSCs possess a mRNA and microRNA transcriptome overall similar to normal myocardium-derived c-kit^pos/CD45^neg/CD31^negCSCs , yet showing a relatively small and relevant fraction of dysregulated mRNA/miRNAs (miR-126-3p and miR-335-5p, in particular). Importantly, myxoma-derived CSCs but not normal myocardium-derived CSCs, seed human myxoma tumours in xenograft’s in immunodeficient NOD/SCID mice.

Conclusion

Myxoma-derived c-kit^pos/CD45^neg/CD31^neg CSCs fulfill the criteria expected of atrial myxoma-initiating stem cells. The transcriptome of these cells indicates that they belong to or are derived from the same lineage as the atrial multipotent c-kit^pos/CD45^neg/CD31^neg CSCs. Taken together the data presented here suggest that human myxomas could be the first-described CSC-related human heart disease.

Role of miRNAs and lncRNAs in hematopoietic stem cell differentiation

Non-coding RNAs (ncRNAs) have diverse roles in the differentiation of hematopoietic cells. Among these transcripts, long ncRNAs (lncRNAs) and microRNAs (miRNAs) have especial contribution in this regard particularly by affecting levels of transcription factors that define differentiation of each linage. miR-222, miR-10a, miR-126, miR-106, miR-10b, miR-17, miR-20, miR-146, miR-155, miR-223, miR-221, miR-92, miR-150, miR-126 and miR-142 are among miRNAs that partake in the differentiation of hematopoietic stem cells. Meanwhile, this process is controlled by a number of lncRNAs such as PU.1-AS, AlncRNA-EC7, EGO, HOTAIRM1, Fas-AS1, LincRNA-EPS and lncRNA-CSR. Manipulation of expression of these transcripts has functional significance in the treatment of cancers and in cell therapy. In this paper, we have provided a brief summary of the role of miRNAs and lncRNAs in the regulation of hematopoietic stem cells.

MiR-181d-5p regulates implant surface roughness-induced osteogenic differentiation of bone marrow stem cells

Constructing moderate surface roughness is a widely used, non-toxic, cost-effective, and outcome-predictable approach to accelerate implant osteointegration in clinical settings. MicroRNAs (miRNAs) play vital regulatory roles in the osteogenic differentiation of bone marrow stem cells (BMSCs). However, their specific contribution to the influence of surface roughness on osteoblastic behavior remains unknown. Therefore, applying the smooth titanium surface as a control, a typical titanium surface with moderate roughness was prepared here to reveal the mechanism through which surface roughness regulates cell osteogenic behavior by altering miRNA expression. First, the morphology and roughness of two surfaces were characterized, and the enhanced osteogenic differentiation of BMSCs on rough surfaces was verified. Then, twenty-nine differentially expressed miRNAs in BMSCs cultured on different surfaces were selected via miRNA chip and corresponding functional prediction. After verifying the expression of these miRNAs using quantitative real-time polymerase chain reaction, four were considered eligible candidates. Among these, only miR-181d-5p significantly affected RUNX2 gene expression based on overexpression and knockdown experiments. From the osteogenesis-related gene and protein expression, as well as alkaline phosphatase and alizarin red experiments, we further confirmed that the downregulation of miR-181d-5p promoted osteogenic differentiation of BMSCs, and vice versa. In addition, rescue assays showed that the knockdown of miR-181d-5p improved the inferior osteogenesis observed on smooth surfaces, whereas the overexpression of miR-181d-5p suppressed the superior osteogenesis observed on rough surfaces. These results indicate that the moderate surface roughness of the implant stimulates the osteogenic differentiation of BMSCs by remarkably downregulating miR-181d-5p. These findings provide helpful information and a theoretical basis for the development of advanced implant materials for fast osteointegration.

MicroRNAs in Platelets: Should I Stay or Should I Go?

In this chapter, we discuss different topics always using the microRNA as the guiding thread of the review. MicroRNAs, member of small noncoding RNAs family, are an important element involved in gene expression. We cover different issues such as their importance in the differentiation and maturation of megakaryocytes (megakaryopoiesis), as well as the role in platelets formation (thrombopoiesis) focusing on the described relationship between miRNA and critical myeloid lineage transcription factors such as RUNX1, chemokines receptors as CRCX4, or central hormones in platelet homeostasis like TPO, as well as its receptor (MPL) and the TPO signal transduction pathway, that is JAK/STAT. In addition to platelet biogenesis, we review the microRNA participation in platelets physiology and function. This review also introduces the use of miRNAs as biomarkers of platelet function since the detection of pathogenic situations or response to therapy using these noncoding RNAs is getting increasing interest in disease management. Finally, this chapter describes the participation of platelets in cellular interplay, since extracellular vesicles have been demonstrated to have the ability to deliver microRNAs to others cells, modulating their function through intercellular communication, redefining the extracellular vesicles from the so-called “platelet dust” to become mediators of intercellular communication.

Post-Transcriptional Expression Control in Platelet Biogenesis and Function

Platelets are highly abundant cell fragments of the peripheral blood that originate from megakaryocytes. Beside their well-known role in wound healing and hemostasis, they are emerging mediators of the immune response and implicated in a variety of pathophysiological conditions including cancer. Despite their anucleate nature, they harbor a diverse set of RNAs, which are subject to an active sorting mechanism from megakaryocytes into proplatelets and affect platelet biogenesis and function. However, sorting mechanisms are poorly understood, but RNA-binding proteins (RBPs) have been suggested to play a crucial role. Moreover, RBPs may regulate RNA translation and decay following platelet activation. In concert with other regulators, including microRNAs, long non-coding and circular RNAs, RBPs control multiple steps of the platelet life cycle. In this review, we will highlight the different RNA species within platelets and their impact on megakaryopoiesis, platelet biogenesis and platelet function. Additionally, we will focus on the currently known concepts of post-transcriptional control mechanisms important for RNA fate within platelets with a special emphasis on RBPs.

Targeting microRNA in hematologic malignancies

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Microarray analysis of differentially expressed microRNAs in myelodysplastic syndromes

BACKGROUND

Our study aimed to analyze differential microRNA expression between myelodysplastic syndromes (MDS) and normal bone marrow, and to identify novel microRNAs relevant to MDS pathogenesis.

METHODS

MiRNA microarray analysis was used to profile microRNA expression levels in MDS and normal bone marrow. Quantitative real-time polymerase chain reaction was employed to verify differentially expressed microRNAs.

RESULTS

MiRNA microarray analysis showed 96 significantly upregulated (eg, miR-146a-5p, miR-151a-3p, miR-125b-5p) and 198 significantly downregulated (eg, miR-181a-2-3p, miR-124-3p, miR-550a-3p) microRNAs in MDS compared with normal bone marrow. The quantitative real-time polymerase chain reaction confirmed the microarray analysis: expression of six microRNAs (miR-155-5p, miR-146a-5p, miR-151a-3p, miR-221-3p, miR-125b-5p, and miR-10a-5p) was significantly higher in MDS, while 3 microRNAs (miR-181a-2-3p, miR-124-3p, and miR-550a-3p) were significantly downregulated in MDS. Bioinformatics analysis demonstrated that differentially expressed microRNAs might participate in MDS pathogenesis by regulating hematopoiesis, leukocyte migration, leukocyte apoptotic process, and hematopoietic cell lineage.

CONCLUSIONS

Our study indicates that differentially expressed microRNAs might play a key role in MDS pathogenesis by regulating potential relevant functional and signaling pathways. Targeting these microRNAs may provide new treatment modalities for MDS.

miRNA-98-5p Targeting IGF2BP1 Induces Mesenchymal Stem Cell Apoptosis by Modulating PI3K/Akt and p53 in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is a common hematological autoimmune disease, in which defective mesenchymal stem cells (MSCs) are potentially involved. Our previous study suggested that MSCs in ITP patients displayed enhanced apoptosis. MicroRNAs (miRNAs) play important roles in ITP by affecting megakaryopoiesis, platelet production and immunoregulation, whereas the roles of miRNAs in ITP-MSCs remain unknown. In a previous study, we performed microarray analysis to obtain mRNA and miRNA profiles of ITP-MSCs. In the present study, we reanalyze the data and identify miR-98-5p as a candidate miRNA contributing to MSC deficiency in ITP. miR-98-5p acts through targeting insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), and the subsequent downregulation of insulin-like growth factor 2 (IGF-2) causes inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which is involved in the process of MSC deficiency. Furthermore, miR-98-5p upregulates p53 by inhibiting β-transducin repeat-containing protein (β-TrCP)-dependent p53 ubiquitination. Moreover, miR-98-5p overexpression impairs the therapeutic effect of MSCs in ITP mice. All-trans retinoic acid (ATRA) protects MSCs from apoptosis by downregulating miR-98-5p, thus providing a potential therapeutic approach for ITP. Our findings demonstrate that miR-98-5p is a critical regulator of ITP-MSCs, which will help us thoroughly understand the pathogenesis of ITP.

Role of non-coding RNA networks in leukemia progression, metastasis and drug resistance

Early-stage detection of leukemia is a critical determinant for successful treatment of the disease and can increase the survival rate of leukemia patients. The factors limiting the current screening approaches to leukemia include low sensitivity and specificity, high costs, and a low participation rate. An approach based on novel and innovative biomarkers with high accuracy from peripheral blood offers a comfortable and appealing alternative to patients, potentially leading to a higher participation rate.

Recently, non-coding RNAs due to their involvement in vital oncogenic processes such as differentiation, proliferation, migration, angiogenesis and apoptosis have attracted much attention as potential diagnostic and prognostic biomarkers in leukemia. Emerging lines of evidence have shown that the mutational spectrum and dysregulated expression of non-coding RNA genes are closely associated with the development and progression of various cancers, including leukemia. In this review, we highlight the expression and functional roles of different types of non-coding RNAs in leukemia and discuss their potential clinical applications as diagnostic or prognostic biomarkers and therapeutic targets.

microRNA-22 promotes megakaryocyte differentiation through repression of its target, GFI1

Precise control of microRNA expression contributes to development and the establishment of tissue identity, including in proper hematopoietic commitment and differentiation, whereas aberrant expression of various microRNAs has been implicated in malignant transformation. A small number of microRNAs are upregulated in megakaryocytes, among them is microRNA-22 (miR-22). Dysregulation of miR-22 leads to various hematologic malignancies and disorders, but its role in hematopoiesis is not yet well established. Here we show that upregulation of miR-22 is a critical step in megakaryocyte differentiation. Megakaryocytic differentiation in cell lines is promoted upon overexpression of miR-22, whereas differentiation is disrupted in CRISPR/Cas9-generated miR-22 knockout cell lines, confirming that miR-22 is an essential mediator of this process. RNA-sequencing reveals that miR-22 loss results in downregulation of megakaryocyte-associated genes. Mechanistically, we identify the repressive transcription factor, GFI1, as the direct target of miR-22, and upregulation of GFI1 in the absence of miR-22 inhibits megakaryocyte differentiation. Knocking down aberrant GFI1 expression restores megakaryocytic differentiation in miR-22 knockout cells. Furthermore, we have characterized hematopoiesis in miR-22 knockout animals and confirmed that megakaryocyte differentiation is similarly impaired in vivo and upon ex vivo megakaryocyte differentiation. Consistently, repression of Gfi1 is incomplete in the megakaryocyte lineage in miR-22 knockout mice and Gfi1 is aberrantly expressed upon forced megakaryocyte differentiation in explanted bone marrow from miR-22 knockout animals. This study identifies a positive role for miR-22 in hematopoiesis, specifically in promoting megakaryocyte differentiation through repression of GFI1, a target antagonistic to this process.

Circulating miR-660-5p is associated with no-reflow phenomenon in patients with ST segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

OBJECTIVE

This study aims to investigate the association of circulating miR-660-5p with no-reflow phenomenon (NRP) in patients with ST segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

METHODS

Consecutive patients diagnosed with anterior STEMI within 12 h of pain onset were included; in these patients, coronary angiography confirmed that the left anterior descending artery was infarcted. Angiographic NRP was defined as a final thrombolysis in myocardial infarction (TIMI) flow 2 or 3 with a myocardial blush grade (MBG) <2. High miR-660-5p was defined as a value in the third tertile. The relationship of circulating miR-660-5p with NRP was assessed using Spearman correlation analysis and multiple logistic regression analysis.

RESULTS

Fifty-two eligible patients were finally included in this study (mean age: 56±12.4 years, >65 years: 53.8%, male: 76.9%, and mean Body Mass Index: 26.3±3.5). The incidence of NRP was 38.5%. Circulating miR-660-5p was significantly related to the mean platelet volume (MPV). The patients were grouped into tertiles by miR-660-5p levels (Q1: <7.18, Q2: 7.18-11.31, Q3: >11.31). Those in the high microRNA-660-5p group had nearly a 6-fold higher risk of NRP than those in the low microRNA-660-5p group [odds ratio (OR) = 5.68, 95% confidence interval (CI) 1.40-23.07, p=0.015]. When analyzed by tertiles, relative odds of NRP were consistently increasing (OR1 for Q2 vs. Q1: 1.25, 95% CI: 0.27-5.73, p=0.770; OR2 for Q3 vs. Q1: 5.96, 95% CI: 1.33-26.66, p=0.02), despite multivariable adjustment. Receiver operating characteristic curve analysis demonstrated that the microRNA-660-5p level of 10.17 was the best cut-off level to predict the incidence of the NRP in patients undergoing PPCI with an area under the ROC curve (AUC) of 0.768 (95% CI: 0.636-0.890).

CONCLUSION

Circulating miR-660-5p was significantly associated with NRP, and it may be a useful biomarker to predict the incidence of NRP in patients with STEMI undergoing PPCI.

Core Binding Factor Leukemia: Chromatin Remodeling Moves Towards Oncogenic Transcription

Acute myeloid leukemia (AML), the most common acute leukemia in adults, is a heterogeneous malignant clonal disorder arising from multipotent hematopoietic progenitor cells characterized by genetic and concerted epigenetic aberrations. Core binding factor-Leukemia (CBFL) is characterized by the recurrent reciprocal translocations t(8;21)(q22;q22) or inv(16)(p13;q22) that, expressing the distinctive RUNX1-RUNX1T1 (also known as Acute myeloid leukemia1-eight twenty-one, AML1-ETO or RUNX1/ETO) or CBFB-MYH11 (also known as CBFβ-ΣMMHX) translocation product respectively, disrupt the essential hematopoietic function of the CBF. In the past decade, remarkable progress has been achieved in understanding the structure, three-dimensional (3D) chromosomal topology, and disease-inducing genetic and epigenetic abnormalities of the fusion proteins that arise from disruption of the CBF subunit alpha and beta genes. Although CBFLs have a relatively good prognosis compared to other leukemia subtypes, 40-50% of patients still relapse, requiring intensive chemotherapy and allogenic hematopoietic cell transplantation (alloHCT). To provide a rationale for the CBFL-associated altered hematopoietic development, in this review, we summarize the current understanding on the various molecular mechanisms, including dysregulation of Wnt/β-catenin signaling as an early event that triggers the translocations, playing a pivotal role in the pathophysiology of CBFL. Translation of these findings into the clinical setting is just beginning by improvement in risk stratification, MRD assessment, and development of targeted therapies.

MicroRNAs as a Potential Quality Measurement Tool of Platelet Concentrate Stored in Blood Banks-A Review

BACKGROUND

Platelet concentrate (PC) is one of the main products used in a therapeutic transfusion. This blood component requires special storage at blood banks, however, even under good storage conditions, modifications or degradations may occur and are known as platelet storage lesions.

METHODS

This research was performed on scientific citation databases PubMed/Medline, ScienceDirect, and Web of Science, for publications containing platelet storage lesions. The results obtained mainly reveal the clinical applicability of miRNAs as biomarkers of storage injury and as useful tools for a problem affecting public and private health, the lack of PC bags in countries with few blood donors. The major studies listed in this review identified miRNAs associated with important platelet functions that are relevant in clinical practice as quality biomarkers of PC, such as miR-223, miR-126, miR-10a, miR-150, miR-16, miR-21, miR-326, miR-495, let-7b, let-7c, let-7e, miR-107, miR-10b, miR-145, miR-155, miR-17, miR-191, miR-197, miR-200b, miR-24, miR-331, miR-376. These miRNAs can be used in blood banks to identify platelet injury in PC bags.

CONCLUSION

The studies described in this review relate the functions of miRNAs with molecular mechanisms that result in functional platelet differences, such as apoptosis. Thus, miRNA profiles can be used to measure the quality of storage PC for more than 5 days, identify bags with platelet injury, and distinguish those with functional platelets.

Microvesicles promote megakaryopoiesis by regulating DNA methyltransferase and methylation of Notch1 promoter

Megakaryopoiesis is the process of formation of mature megakaryocytes that takes place in the bone marrow niche resulting in the release of platelets into the peripheral blood. It has been suggested that cell to cell communication in this dense bone marrow niche may influence the fate of the cells. Numerous studies point to the role of exosomes and microvesicles not only as a messenger of the cellular crosstalk but also in growth and developmental process of various cell types. In the current study, we explored the effects of megakaryocyte-derived microvesicles in hematopoietic cell lines in the context of differentiation. Our study demonstrated that microvesicles isolated from the induced megakaryocytic cell lines have the ability to stimulate noninduced cells specifically into that particular lineage. We showed that this lineage commencement comes from the change in the methylation status of Notch1 promoter, which is regulated by DNA methyltransferases.

Role of sepsis modulated circulating microRNAs

Sepsis is a life-threating condition with dysregulated systemic host response to microbial pathogens leading to disproportionate inflammatory response and multi-organ failure. Various biomarkers are available for the diagnosis and prognosis of sepsis; however, these laboratory parameters may show limitations in these severe clinical conditions. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of post-transcriptional gene silencing. They normally control numerous intracellular events, such as signaling cascade downstream of Toll-like receptors (TLRs) to avoid excessive inflammation after infection. In contrast, abnormal miRNA expression contributes to the development of sepsis correlating with its clinical features and outcomes. Based on recent clinical studies altered levels of circulating miRNAs can act as potential diagnostic and prognostic biomarkers in sepsis. In this review, we summarized the available data about TLR-mediated inflammatory signaling with its intracellular response in immune cells and platelets upon sepsis, which are, at least in part, under the regulation of miRNAs. Furthermore, the role of circulating miRNAs is also described as potential laboratory biomarkers in sepsis.

MicroRNAs as regulators and effectors of hematopoietic transcription factors

Hematopoiesis is a highly-regulated development process orchestrated by lineage-specific transcription factors that direct the generation of all mature blood cells types, including red blood cells, megakaryocytes, granulocytes, monocytes, and lymphocytes. Under homeostatic conditions, the hematopoietic system of the typical adult generates over 10¹¹ blood cells daily throughout life. In addition, hematopoiesis must be responsive to acute challenges due to blood loss or infection. MicroRNAs (miRs) cooperate with transcription factors to regulate all aspects of hematopoiesis, including stem cell maintenance, lineage selection, cell expansion, and terminal differentiation. Distinct miR expression patterns are associated with specific hematopoietic lineages and stages of differentiation and functional analyses have elucidated essential roles for miRs in regulating cell transitions, lineage selection, maturation, and function. MiRs function as downstream effectors of hematopoietic transcription factors and as upstream regulators to control transcription factor levels. Multiple miRs have been shown to play essential roles. Regulatory networks comprised of differentially expressed lineage-specific miRs and hematopoietic transcription factors are involved in controlling the quiescence and self-renewal of hematopoietic stem cells as well as proliferation and differentiation of lineage-specific progenitor cells during erythropoiesis, myelopoiesis, and lymphopoiesis. This review focuses on hematopoietic miRs that function as upstream regulators of central hematopoietic transcription factors required for normal hematopoiesis. This article is categorized under: RNA in Disease and Development > RNA in Development Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.

miR-126: An indicator of poor prognosis and recurrence in histologically lymph node-negative gastric cancer

BACKGROUND

Few biomarkers are available for the prediction of prognosis and recurrence in lymph node (LN)-negative gastric cancer (GC) currently. miR-126 functions as a tumor suppressor in GC, however, its clinical significance in LN-negative GC remains unknown.

AIM

To investigate the associations of tissue miR-126 level with the clinicopathological characteristics and clinical outcome of LN-negative GC patients.

METHODS

Quantitative real-time polymerase chain reaction was performed to examine the tissue miR-126 level in 315 LN-negative GC patients who underwent curative gastrectomy with D2 lymphadenectomy. The associations of tissue miR-126 level with clinicopathological characteristics and clinical outcome were evaluated.

RESULTS

Compared with matched adjacent non-tumor tissues, miR-126 expression was significantly down-regulated in tumor tissues. A reduced tissue miR-126 level statistically correlated with aggressive clinicopathological characteristics, including larger tumor size, deeper local invasion, and poorer prognosis. Notably, multivariate analysis identified advanced T stage and low miR-126 level as independent predictors of the unfavorable prognosis and recurrence of LN-negative GC.

CONCLUSIONS

These results indicate for the first time that advanced T stage and low miR-126 level are predictors of unfavorable prognosis and recurrence in LN-negative GC patients. These parameters should be taken into account to stratify patients for adjuvant therapy and close follow-up.

miR-15a-5p regulates expression of multiple proteins in the megakaryocyte GPVI signaling pathway

Essentials The action of microRNAs (miRs) in human megakaryocyte signaling is largely unknown. Cord blood-derived human megakaryocytes (MKs) were used to test the function of candidate miRs. miR-15a-5p negatively regulated MK GPVI-mediated αIIbβ3 activation and α-granule release. miR-15a-5p acts as a potential "master-miR" regulating genes in the MK GPVI signaling pathway. SUMMARY: Background Megakaryocytes (MKs) invest their progeny platelets with proteins and RNAs. MicroRNAs (miRs), which inhibit mRNA translation into protein, are abundantly expressed in MKs and platelets. Although platelet miRs have been associated with platelet reactivity and disease, there is a paucity of information on the function of miRs in human MKs. Objective To identify MK miRs that regulate the GPVI signaling pathway in the MK-platelet lineage. Methods Candidate miRs associated with GPVI-mediated platelet aggregation were tested for functionality in cultured MKs derived from cord blood. Results An unbiased, transcriptome-wide screen in 154 healthy donors identified platelet miR-15a-5p as significantly negatively associated with CRP-induced platelet aggregation. Platelet agonist dose-response curves demonstrated activation of αIIbβ3 in suspensions of cord blood-derived cultured MKs. Overexpression and knockdown of miR-15a-5p in these MKs reduced and enhanced, respectively, CRP-induced αIIbβ3 activation but did not alter thrombin or ADP stimulation. FYN, SRGN, FCER1G, MYLK. and PRKCQ, genes involved in GPVI signaling, were identified as miR-15a-5p targets and were inhibited or de-repressed in MKs with miR-15a-5p overexpression or inhibition, respectively. Lentiviral overexpression of miR-15a-5p also inhibited GPVI-FcRγ-mediated phosphorylation of Syk and PLCγ2, GPVI downstream signaling molecules, but effects of miR-15a-5p on αIIbβ3 activation did not extend to other ITAM-signaling receptors (FcγRIIa and CLEC-2). Conclusion Cord blood-derived MKs are a useful human system for studying the functional effects of candidate platelet genes. miR-15a-5p is a potential "master-miR" for specifically regulating GPVI-mediated MK-platelet signaling. Targeting miR-15a-5p may have therapeutic potential in hemostasis and thrombosis.

Expression and prognostic significance of microRNAs in Korean patients with myelodysplastic syndrome

BACKGROUND/AIMS

Various alterations of microRNA (miRNA) expression have been reported in myelodysplastic syndrome (MDS). We aimed to investigate the unique patterns and prognostic significance of miRNA expression in Korean patients with MDS.

METHODS

Bone marrow mononuclear cells were collected from eight healthy controls and 26 patients with MDS, and miRNAs were isolated and assessed via quantitative real-time polymerase chain reaction for selected miRNAs, including miR-21, miR-124a, miR-126, miR-146b-5p, miR-155, miR-182, miR-200c, miR-342-5p, miR-708, and Let-7a.

RESULTS

MiR-124a, miR-155, miR-182, miR-200c, miR-342-5p, and Let-7a were significantly underexpressed in patients with MDS, compared to healthy controls. MiR-21, miR-126, 146b-5p, and miR-155 transcript levels were significantly lower in international prognostic scoring system lower (low and intermediate-1) risk MDS than in higher (intermediate-2 and high) risk MDS. Higher expression levels of miR-126 and miR-155 correlated with significantly shorter overall survival and leukemia-free survival. Higher miR-124a expression also tended to be related to shorter survivals.

CONCLUSION

Although our study was limited by the relatively small number of patients included, we identified several miRNAs associated with pathogenesis, leukemic transformation, and prognosis in MDS.

MiR-10a and HOXB4 are overexpressed in atypical myeloproliferative neoplasms

Background

Atypical Myeloproliferative Neoplasms (aMPN) share characteristics of MPN and Myelodysplastic Syndromes. Although abnormalities in cytokine signaling are common in MPN, the pathophysiology of atypical MPN still remains elusive. Since deregulation of microRNAs is involved in the biology of various cancers, we studied the miRNome of aMPN patients.

Methods

MiRNome and mutations in epigenetic regulator genes ASXL1, TET2, DNMT3A, EZH2 and IDH1/2 were explored in aMPN patients. Epigenetic regulation of miR-10a and HOXB4 expression was investigated by treating hematopoietic cell lines with 5-aza-2’deoxycytidine, valproic acid and retinoic acid. Functional effects of miR-10a overexpression on cell proliferation, differentiation and self-renewal were studied by transducing CD34⁺ cells with lentiviral vectors encoding the pri-miR-10a precursor.

Results

MiR-10a was identified as the most significantly up-regulated microRNA in aMPN. MiR-10a expression correlated with that of HOXB4, sitting in the same genomic locus. The transcription of these two genes was increased by DNA demethylation and histone acetylation, both necessary for optimal expression induction by retinoic acid. Moreover, miR-10a and HOXB4 overexpression seemed associated with DNMT3A mutation in hematological malignancies. However, overexpression of miR-10a had no effect on proliferation, differentiation or self-renewal of normal hematopoietic progenitors.

Conclusions

MiR-10a and HOXB4 are overexpressed in aMPN. This overexpression seems to be the result of abnormalities in epigenetic regulation mechanisms. Our data suggest that miR-10a could represent a simple marker of transcription at this genomic locus including HOXB4, widely recognized as involved in stem cell expansion.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4993-2) contains supplementary material, which is available to authorized users.

Serum miR-126 level combined with multi- detector computed tomography in the preoperative prediction of lymph node metastasis of gastric cancer

BACKGROUND

Predicting lymph node metastasis (LNM) accurately is vital to design optimal treatment strategies preoperatively for gastric cancer (GC) patients. However, conventional tumor biomarkers and imaging techniques are not sufficient to predict LNM before surgery. miR-126 has been reported to play important roles in tumor metastasis which may represent a novel tumor biomarker.

OBJECTIVE

To assess the utility of the combination of serum miR-126 and multi-detector computed tomography (MDCT) in predicting LNM preoperatively in GC.

METHODS

Quantitative real-time polymerase chain reaction was performed to examine the serum miR-126 expression levels in 338 GC patients. MDCT was also performed. The cut-off value of preoperative serum miR-126 level for LNM was determined by receiver characteristic curve (ROC) analysis. Logistic regression analysis was used to determine independent predictors for LNM.

RESULTS

The serum miR-126 levels of GC patients with LNM were significantly lower compared with those without LNM (p< 0.05). In addition, the later the N stage was, the lower the serum miR-126 level was in GC patients (p< 0.05). With a cut-off value of 63.4, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of serum miR-126 for predicating LNM were 83.2%, 79.0%, 81.9%, 90.4% and 66.4%, respectively. The combination of serum miR-126 level and MDCT increased the accuracy of MDCT prediction for LNM from 69.2% to 86.7%. Serum miR-126 was an independent predictor for LNM.

CONCLUSIONS

These results indicate for the first time that the combination of serum miR-126 and MDCT is useful for the prediction of LNM in GC.

Down-regulated serum miR-126 is associated with aggressive progression and poor prognosis of gastric cancer

BACKGROUND

miR-126 functions as a tumor suppressor in gastric cancer (GC), however, the clinical significance of serum miR-126 in GC remains unclear.

OBJECTIVE

To investigate the associations of serum miR-126 level with the clinicopathological characteristics and prognosis of GC patients.

METHODS

Quantitative real-time polymerase chain reaction was performed to examine the expression levels of miR-126 in 338 GC patients' tissues and sera, and 50 healthy controls' sera. The associations of serum miR-126 with clinicopathological characteristics and clinical outcome were evaluated.

RESULTS

Compared with the matched adjacent non-tumor tissues and normal sera, miR-126 expression was significantly down-regulated in both tumor tissues and sera of GC patients. Importantly, there was a positive correlation between tissue and serum levels of miR-126 in GC patients. A reduced serum miR-126 level statistically correlated with aggressive clinicopathological characteristics, such as larger tumor size, deeper local invasion, more lymph node metastasis, advanced TNM stage, and poorer prognosis. Notably, multivariate analysis identified reduced serum miR-126 level as an independent predictor for the unfavorable prognosis of GC.

CONCLUSIONS

These results indicate for the first time that serum miR-126 may serve as a novel prognostic biomarker in GC.

Genomics and transcriptomics of megakaryocytes and platelets: Implications for health and disease

The field of megakaryocyte and platelet biology has been transformed with the implementation of high throughput sequencing. The use of modern sequencing technologies has led to the discovery of causative mutations in congenital platelet disorders and has been a useful tool in uncovering many other mechanisms of altered platelet formation and function. Although the understanding of the presence of RNA in platelets is relatively novel, mRNA and miRNA expression profiles are being shown to play an increasingly important role in megakaryopoiesis and platelet function in normal physiology as well as in disease states. Understanding the genetic perturbations underlying platelet dysfunction provides insight into normal megakaryopoiesis and thrombopoiesis, as well as guiding the development of novel therapeutics.

Monitoring of platelet function parameters and microRNA expression levels in patients with prostate cancer treated with volumetric modulated arc radiotherapy

Radiotherapy (RT) may result in platelet activation and thrombosis development. To the best of our knowledge, the potential effect of volumetric-modulated arc therapy (VMAT), a novel radiotherapy technique, on platelet function and microRNA (miRNA/miR) expression has not been previously investigated. The present study aimed to determine the effect of VMAT on the alterations in platelet function parameters and miRNA expression levels. A total of 25 patients with prostate cancer and 25 healthy subjects were included in the present study. Blood samples were collected from the patient group on the day prior to RT (pre-RT), the day RT was completed (post-RT day 0), and 40 days following the end of therapy (post-RT day 40). Platelet count, mean platelet volume (MPV) value, platelet aggregation, plasma P-selectin, thrombospondin-1, platelet factor 4, plasma miR-223 and miR-126 expression levels were measured. A significant decrease in platelet count in the post-RT day 0 group was measured in comparison with the pre-RT and the post-RT day 40 groups. Pre-RT MPV values were higher than those of the post-RT day 0 and the post-RT day 40 groups. No significant differences were observed in the levels of platelet activation markers or miR-223 and miR-126 expression levels between the RT groups. Although RT may result in a reduction in platelet and MPV counts, the results of the present study indicate that platelet activation markers are not affected by VMAT. Therefore, it is possible that no platelet activation occurs during VMAT, owing to the conformal dose distributions, improved target volume coverage and the sparing of normal tissues from undesired radiation.

Platelet-Enriched MicroRNAs and Cardiovascular Homeostasis

SIGNIFICANCE

Platelets are anucleate blood cells that are involved in hemostasis and thrombosis. Although no longer able to generate ribonucleic acid (RNA) de novo, platelets contain messenger RNA (mRNA), YRNA fragments, and premature microRNAs (miRNAs) that they inherit from megakaryocytes. Recent Advances: Novel sequencing techniques have helped identify the unexpectedly large number of RNA species present in platelets. Throughout their life time, platelets can process the pre-existing pool of premature miRNA to give the fully functional miRNA that can regulate platelet protein expression and function.

CRITICAL ISSUES

Platelets make a major contribution to the circulating miRNA pool but platelet activation can have major consequences on Dicer levels and thus miRNA maturation, which has implications for studies that are focused on screening-stored platelets.

FUTURE DIRECTIONS

It will be important to determine the importance of platelets as donors for miRNA-containing microvesicles that can be taken up and processed by other (particularly vascular) cells, thus contributing to homeostasis as well as disease progression. Antioxid. Redox Signal. 29, 902-921.

Aerobic training improves platelet function in type 2 diabetic patients: role of microRNA-130a and GPIIb

AIMS

MicroRNAs (miRs) that are mediators of gene expression have been implicated in type 2 diabetes mellitus (T2DM). Platelet hyper-reactivity is one of the most important disorders in T2DM patients. In this study, we explored the effects of aerobic training (AT) on platelet aggregation and Glycoprotein IIb (GPIIb) receptor and miR-130a expression.

METHODS

In a quasi-experimental controlled trial, 24 sedentary, eligible female participants with T2DM were selected (age 61.92 ± 3.63) and divided into AT and control (CON) groups based on their peak oxygen consumption (VO_2peak). AT protocol was performed three times per week in non-consecutive days on a treadmill with mean intensity (60-75% VO_2peak) for 8 weeks, while the control group refrained from any type of exercise training. Two blood samples were taken before and after this period. Real-time PCR was used to determine the expression of platelet GPIIb and miR-130a. Moreover, platelet indices (PLT, MPV, PDW, and PCT), collagen-induced platelet aggregation and glycemic variables were measured.

RESULTS

Analyses of data showed that anthropometric variables, VO_2peak and glycemic control improved significantly (P < 0.01) after AT. Furthermore, MPV, PDW (P < 0.01), and platelet aggregation (P < 0.001) decreased significantly following AT compared with control group. Platelet GPIIb expression down-regulated significantly (P < 0.05) in AT group but up-regulation of miR-130a expression was not significant between two groups (P > 0.05).

CONCLUSIONS

Platelet hyper-reactivity in T2DM females might be decreased not only by glycemic control and amelioration of anthropometric and platelet indices, but also the down-regulation of GPIIb following AT. However, more research is needed to determine the effects of exercise training on platelet miR-130a.

Dysregulation of miR-126/Crk protein axis predicts poor prognosis in gastric cancer patients

BACKGROUND

miR-126 functions as a tumor suppressor in gastric cancer (GC) by negatively regulating Crk protein expression post-transcriptionally.

OBJECTIVE

The aim of this study was to investigate the associations of miR-126 and Crk protein expression levels, alone or in combination, with the clinicopathological characteristics and prognosis of GC patients.

METHODS

The expression levels of miR-126 and Crk protein in 338 GC patients were analyzed by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively. The relationship of miR-126 and Crk protein expression with clinicopathologic characteristics and clinical outcome was evaluated.

RESULTS

Compared with matched adjacent non-tumor tissues, miR-126 was significantly down-regulated while Crk protein was significantly up-regulated in tumor tissues. A reduced miR-126 expression and an elevated Crk protein expression, alone or in combination, statistically correlated with aggressive clinicopathological characteristics, such as larger tumor size, deeper local invasion, more lymph node metastasis, advanced TNM stage, and poorer prognosis. Multivariate analysis showed that combined miR-126-low/Crk protein-high expression was an independent unfavorable prognostic factor of GC.

CONCLUSIONS

These results indicate for the first time that miR-126 down-regulation and Crk protein up-regulation may be synergistically associated with tumor progression in GC and may predict unfavorable prognosis of GC.

MicroRNAs as potential regulators of platelet function and bleeding diatheses

Although a growing number of studies suggest that microRNAs (miRNAs) play a relevant role in platelet biology, their implications in bleeding diatheses are starting to be investigated. Indeed, several studies have shown that alterations in the intracellular levels of highly expressed platelet miRNAs provoke a thrombotic phenotype. On the other hand, primary immune thrombocytopenia (ITP), which is considered the hallmark of acquired bleeding disorders, has been recently associated with altered levels of miRNAs in peripheral blood mononuclear cells, plasma, and platelets. In this review, we will focus on miRNAs that may affect the hemostatic and thrombotic functions of platelets, and we will discuss the different studies that have attempted to associate miRNAs with regulatory mechanisms of ITP.

Platelets activated by the anti-β2GPI/β2GPI complex release microRNAs to inhibit migration and tube formation of human umbilical vein endothelial cells

Background

Patients with anti-β2GPI antibodies display significantly higher platelet activation/aggregation and vascular endothelial cell damage. The mechanism underlying the correlation between platelet activation, vascular endothelial cell dysfunctions and anti-β2GPI antibodies remains unknown.

Methods

In this study, we derived miR-96 and -26a from platelets activated by the anti-β2GPI/β2GPI complex and explored their role in modulating human umbilical vein endothelial cell (HUVEC) migration and tube formation.

Results

Anti-β2GPI/β2GPI complex induces the release of platelet-derived microparticles (p-MPs). The amounts of miR-96 and -26a in these p-MPs were also higher than for the control group. Co-incubation of HUVECs with p-MPs resulted in the transfer of miR-96 and -26a into HUVECs, where they inhibited migration and tube formation. The targeting role of these miRNAs was further validated by directly downregulating targeted selectin-P (SELP) and platelet-derived growth factor receptor alpha (PDGFRA) via luciferase activity assay.

Conclusion

Our study suggests that miR-96 and -26a in p-MPs can inhibit HUVEC behavior by targeting SELP and PDGFRA.

Identifying microRNA determinants of human myelopoiesis

Myelopoiesis involves differentiation of hematopoietic stem cells to cellular populations that are restricted in their self-renewal capacity, beginning with the common myeloid progenitor (CMP) and leading to mature cells including monocytes and granulocytes. This complex process is regulated by various extracellular and intracellular signals including microRNAs (miRNAs). We characterised the miRNA profile of human CD34⁺CD38⁺ myeloid progenitor cells, and mature monocytes and granulocytes isolated from cord blood using TaqMan Low Density Arrays. We identified 19 miRNAs that increased in both cell types relative to the CMP and 27 that decreased. miR-125b and miR-10a were decreased by 10-fold and 100-fold respectively in the mature cells. Using in vitro granulopoietic differentiation of human CD34⁺ cells we show that decreases in both miR-125b and miR-10a correlate with a loss of CD34 expression and gain of CD11b and CD15 expression. Candidate target mRNAs were identified by co-incident predictions between the miRanda algorithm and genes with increased expression during differentiation. Using luciferase assays we confirmed MCL1 and FUT4 as targets of miR-125b and the transcription factor KLF4 as a target of miR-10a. Together, our data identify miRNAs with differential expression during myeloid development and reveal some relevant miRNA-target pairs that may contribute to physiological differentiation.