Circulating microRNAs in patients with immune thrombocytopenia before and after treatment with thrombopoietin-receptor agonists

Immune thrombocytopenia: Pathophysiology and impacts of Romiplostim treatment

Immune thrombocytopenia (ITP) is an autoimmune bleeding disease caused by immune-mediated platelet destruction and decreased platelet production. ITP is characterized by an isolated thrombocytopenia (<100 × 109/L) and increased risk of bleeding. The disease has a complex pathophysiology wherein immune tolerance breakdown leads to platelet and megakaryocyte destruction. Therapeutics such as corticosteroids, intravenous immunoglobulins (IVIg), rituximab, and thrombopoietin receptor agonists (TPO-RAs) aim to increase platelet counts to prevent hemorrhage and increase quality of life. TPO-RAs act via stimulation of TPO receptors on megakaryocytes to directly stimulate platelet production. Romiplostim is a TPO-RA that has become a mainstay in the treatment of ITP. Treatment significantly increases megakaryocyte maturation and growth leading to improved platelet production and it has recently been shown to have additional immunomodulatory effects in treated patients. This review will highlight the complex pathophysiology of ITP and discuss the usage of Romiplostim in ITP and its ability to potentially immunomodulate autoimmunity.

The miR-641-STIM1 and SATB1 axes play important roles in the regulation of the Th17/Treg balance in ITP

Immune thrombocytopenia (ITP) is an autoimmune disease caused by T-cell dysfunction. Recently, several studies have shown that a disturbed Th17/Treg balance contributes to the development of ITP. MicroRNAs (miRNAs) are small noncoding RNA moleculesthat posttranscriptionally regulate gene expression. Emerging evidences have demonstrated that miRNAs play an important role in regulating the Th17/Treg balance. In the present study, we found that miR-641 was upregulated in ITP patients. In primary T cells, overexpression of miR-641 could cause downregulation of its target genes STIM1 and SATB1, thus inducing a Th17 (upregulated)/Treg (downregulated) imbalance. Inhibition of miR-641 by a miR-641 sponge in primary T cells of ITP patients or by antagomiR-641 in an ITP murine model could cause upregulation of STIM1 and SATB1, thus restoring Th17/Treg homeostasis. These results suggested that the miR-641-STIM/SATB1 axis plays an important role in regulating the Th17/Treg balance in ITP.

miR-4482 and miR-3912 aim for 3'UTR of ERG mRNA in prostate cancer

Ets-related gene (ERG) is overexpressed as a fusion protein in prostate cancer. During metastasis, the pathological role of ERG is associated with cell proliferation, invasion, and angiogenesis. Here, we hypothesized that miRNAs regulate ERG expression through its 3'UTR. Several bioinformatics tools were used to identify miRNAs and their binding sites on 3'UTR of ERG. The selected miRNAs expression was analyzed in prostate cancer samples by qPCR. The miRNAs overexpression was induced in prostate cancer cells (VCaP) to analyze ERG expression. Reporter gene assay was performed to evaluate the ERG activity in response to selected miRNAs. The expression of ERG downstream target genes was also investigated through qPCR after miRNAs overexpression. To observe the effects of selected miRNAs on cell proliferation and migration, scratch assay was performed to calculate the cell migration rate. miR-4482 and miR-3912 were selected from bioinformatics databases. miR-4482 and -3912 expression were decreased in prostate cancer samples, as compared to controls (p<0.05 and p<0.001), respectively. Overexpression of miR-4482 and miR-3912 significantly reduced ERG mRNA (p<0.001 and p<0.01), respectively) and protein (p<0.01) in prostate cancer cells. The transcriptional activity of ERG was significantly reduced (p<0.01) in response to miR-4482 and-3912. ERG angiogenic targets and cell migration rate was also reduced significantly (p<0.001) after miR-4482 and -3912 over-expression. This study indicates that miR-4482 and -3912 can suppress the ERG expression and its target genes, thereby, halt prostate cancer progression. These miRNAs may be employed as a potential therapeutic target for the miRNA-based therapy against prostate cancer.

Accessory spleens recapitulate the immune microenvironment of the main spleen in immune thrombocytopenia

Accessory spleens (AcS) may play a relevant role in immune thrombocytopenia (ITP) and possibly contribute to ITP relapse following splenectomy. Little is known about the immune microenvironment of AcS in ITP. To address this issue, we compared the histological features of eight matched AcS and main spleen (MS) samples, obtained from adult patients with primary ITP. AcS and MS had overlapping immune architectural features and lymphoid composition, suggesting that similar immunologic events occur in AcS and MS of ITP. These findings may have implications for the potential mechanisms of AcS-mediated ITP relapse. Further studies are needed to confirm these results and to dissect spleen immunity in ITP.

Scoping Review on Epigenetic Mechanisms in Primary Immune Thrombocytopenia

Immune Thrombocytopenia (ITP) is an autoimmune blood disorder that involves multiple pathways responsible for the homeostasis of the immune system. Numerous pieces of literature have proposed the potential of immune-related genes as diagnostic and prognostic biomarkers, which mostly implicate the role of B cells and T cells in the pathogenesis of ITP. However, a more in-depth understanding is required of how these immune-related genes are regulated. Thus, this scoping review aims to collate evidence and further elucidate each possible epigenetics mechanism in the regulation of immunological pathways pertinent to the pathogenesis of ITP. This encompasses DNA methylation, histone modification, and non-coding RNA. A total of 41 studies were scrutinized to further clarify how each of the epigenetics mechanisms is related to the pathogenesis of ITP. Identifying epigenetics mechanisms will provide a new paradigm that may assist in the diagnosis and treatment of immune thrombocytopenia.

The Extensive Regulation of MicroRNA in Immune Thrombocytopenia

MicroRNA (miRNA) is a small, single-stranded, non-coding RNA molecule that plays a variety of key roles in different biological processes through post-transcriptional regulation of gene expression. MiRNA has been proved to be a variety of cellular processes involved in development, differentiation, signal transduction, and is an important regulator of immune and autoimmune diseases. Therefore, it may act as potent modulators of the immune system and play an important role in the development of several autoimmune diseases. Immune thrombocytopenia (ITP) is an autoimmune systemic disease characterized by a low platelet count. Several studies suggest that like other autoimmune disorders, miRNAs are deeply involved in the pathogenesis of ITP, interacting with the function of innate and adaptive immune responses. In this review, we discuss emerging knowledge about the function of miRNAs in ITP and describe miRNAs in terms of their role in the immune system and autoimmune response. These findings suggest that miRNA may be a useful therapeutic target for ITP by regulating the immune system. In the future, we need to have a more comprehensive understanding of miRNAs and how they regulate the immune system of patients with ITP.

Screening Analysis of Platelet miRNA Profile Revealed miR-142-3p as a Potential Biomarker in Modeling the Risk of Acute Coronary Syndrome

Transcriptome analysis constitutes one of the major methods of elucidation of the genetic basis underlying the pathogenesis of various diseases. The post-transcriptional regulation of gene expression is mainly provided by microRNAs. Their remarkable stability in biological fluids and their high sensitivity to disease alteration indicates their potential role as biomarkers. Given the high mortality and morbidity of cardiovascular diseases, novel predictive biomarkers are sorely needed. Our study focuses for the first time on assessing potential biomarkers of acute coronary syndrome (ACS) based on the microRNA profiles of platelets. The study showed the overexpression of eight platelet microRNAs in ACS (miR-142-3p; miR-107; miR-338-3p, miR-223-3p, miR-21-5p, miR-130b-3p, miR-301a-3p, miR-221-3p) associated with platelet reactivity and functionality. Our results show that the combined model based on miR-142-3p and aspartate transaminase reached 82% sensitivity and 88% specificity in the differentiation of the studied groups. Furthermore, the analyzed miRNAs were shown to cluster into two orthogonal groups, regulated by two different biological factors. Bioinformatic analysis demonstrated that one group of microRNAs may be associated with the physiological processes of platelets, whereas the other group may be linked to platelet-vascular environment interactions. This analysis paves the way towards a better understanding of the role of platelet microRNAs in ACS pathophysiology and better modeling of the risk of ACS.

Platelets in ITP: Victims in Charge of Their Own Fate?

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder. The pathophysiological mechanisms leading to low platelet levels in ITP have not been resolved, but at least involve autoantibody-dependent and/or cytotoxic T cell mediated platelet clearance and impaired megakaryopoiesis. In addition, T cell imbalances involving T regulatory cells (Tregs) also appear to play an important role. Intriguingly, over the past years it has become evident that platelets not only mediate hemostasis, but are able to modulate inflammatory and immunological processes upon activation. Platelets, therefore, might play an immuno-modulatory role in the pathogenesis and pathophysiology of ITP. In this respect, we propose several possible pathways in which platelets themselves may participate in the immune response in ITP. First, we will elaborate on how platelets might directly promote inflammation or stimulate immune responses in ITP. Second, we will discuss two ways in which platelet microparticles (PMPs) might contribute to the disrupted immune balance and impaired thrombopoiesis by megakaryocytes in ITP. Importantly, from these insights, new starting points for further research and for the design of potential future therapies for ITP can be envisioned.

Dysregulated expression of miRNAs in immune thrombocytopenia

In recent years the critical role of miRNAs has been established in many diseases, including autoimmune disorders. Immune thrombocytopenia purpura (ITP) is a predominant autoimmune disease, in which aberrant expression of miRNAs has been observed, suggesting that miRNAs are involved in its development. miRNAs could induce an imbalance in the T helper (Th)1/Th2 cell and Th17/Treg cell-related responses. Moreover, they could also cause alterations in Th9 and Th22 cell responses, and activate Tfh (T follicular helper) cell-dependent auto-reactive B cells, thus influencing megakaryogenesis. Herein, we summarize the role of immune-related miRNAs in ITP pathogenesis, and look forward to clinical applications.

Potential Diagnostic Approaches for Prediction of Therapeutic Responses in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder in which, via unresolved mechanisms, platelets and megakaryocytes (MKs) are targeted by autoantibodies and/or T cells resulting in increased platelet destruction and impairment of MK function. Over the years, several therapeutic modalities have become available for ITP, however, therapeutic management has proven to be very challenging in several cases. Patients refractory to treatment can develop a clinically worsening disease course, treatment-induced toxicities and are predisposed to development of potentially life-endangering bleedings. It is therefore of critical importance to timely identify potential refractory patients, for which novel diagnostic approaches are urgently needed in order to monitor and predict specific therapeutic responses. In this paper, we propose promising diagnostic investigations into immune functions and characteristics in ITP, which may potentially be exploited to help predict platelet count responses and thereby distinguish therapeutic responders from non-responders. This importantly includes analysis of T cell homeostasis, which generally appears to be disturbed in ITP due to decreased and/or dysfunctional T regulatory cells (Tregs) leading to loss of immune tolerance and initiation/perpetuation of ITP, and this may be normalized by several therapeutic modalities. Additional avenues to explore in possible prediction of therapeutic responses include examination of platelet surface sialic acids, platelet apoptosis, monocyte surface markers, B regulatory cells and platelet microparticles. Initial studies have started evaluating these markers in relation to response to various treatments including glucocorticosteroids (GCs), intravenous immunoglobulins (IVIg) and/or thrombopoietin receptor agonists (TPO-RA), however, further studies are highly warranted. The systematic molecular analysis of a broad panel of immune functions may ultimately help guide and improve personalized therapeutic management in ITP.

Extracellular vesicles derived from miR-199a-5p-modified adipose-derived mesenchymal stem cells alleviate immune thrombocytopenia by inhibiting T helper 17 differentiation

The abnormal differentiation of T helper 17 (Th17) cells is considered a vital promoter of immune thrombocytopenia (ITP) progression. Therefore, this study investigated the role of miR-199a-5p in Th17 differentiation and determined whether extracellular vesicles (EVs) derived from miR-199a-5p-modified adipose-derived mesenchymal stem cells (ADSCs) could relieve ITP by inhibiting Th17 differentiation. The miR-199a-5p level was lessened in the spleen tissues of mice with ITP, while the signal transducer and activator of transcription 3 (STAT3) expression and the population of Th17 in CD4+T cells were boosted. Functionally, miR-199a-5p overexpression lowered IL-17 secretion and the proportion of Th17/CD4+T cells. Further investigation showed that miR-199a-5p directly targeted STAT3 mRNA, and negatively modulated its expression. STAT3 overexpression was found to facilitate Th17 differentiation, which was subsequently abolished by miR-199a-5p overexpression. EVs isolated from miR-199a-5p-modified ADSCs (miR-199a-5p-EVs) highly expressed miR-199a-5p and could restrain CD4+T cells polarized toward a Th17 phenotype in vitro. Administering of miR-199a-5p-EVs elevated platelet counts and decreased the proportion of Th17/CD4+T cells in mice with ITP. Taken together, EVs derived from miR-199a-5p-modified ADSCs vividly repressed Th17 differentiation by transferring miR-199a-5p to CD4+T cells, thus ameliorating experimental ITP.

Analysis of the expression profile of long non-coding RNAs MALAT1 and THRIL in children with immune thrombocytopenia

BACKGROUND/AIMS

Pediatric immune thrombocytopenia (ITP) is an autoimmune disease; whose etiology is not exactly understood and seems to be highly multifactorial. Long non-coding RNAs (lncRNAs) are key regulators of different actions, which contribute to the development of many autoimmune diseases. To gain a further understanding, we estimated the relative expression of lncRNAs Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and tumor necrosis factor-α (TNF-α) and heterogeneous nuclear ribonucleoprotein L (hnRNPL) immune-regulatory lncRNA (THRIL) in pediatric ITP.

METHODS

In this case-control study, analysis of the expression profiles of these lncRNAs in blood samples from children with ITP and healthy controls (HCs) using quantitative real-time PCR was done. The association of MALAT1 and THRIL with ITP clinical features and their potential usage as non-invasive circulating biomarkers for ITP diagnosis was also evaluated. The receiver operating characteristic curve was constructed, and an area under the curve was analyzed.

RESULTS

Both lncRNAs MALAT1 and THRIL were significantly upregulated in ITP patients in comparison to HCs ( p < .0001 and = .001 respectively). In addition, there was a positive significant correlation between the expression level of both biomarkers among patients (r = 0.745, p < .0001). At cutoff points of 1.17 and 1.27 for lncRNAs MALAT1and THRIL, respectively, both biomarkers had an excellent specificity (100% for both) and fair sensitivity (63.6 and 73.3% for lncRNAs MALAT1and THRIL, respectively). Improvement of biomarkers specificity was obtained by evaluation of the combined expression of both biomarkers. Serum lncRNAs MALAT1 and THRIL could be used as potential biomarkers in differentiating childhood ITP patients and HCs.

Circulating microRNA Expression Profiling Identifies miR-125a-5p Promoting T Helper 1 Cells Response in the Pathogenesis of Hashimoto's Thyroiditis

MicroRNAs (miRNAs) have emerged as key regulators of cellular processes by suppressing target mRNAs at the posttranscriptional level. However, little is known regarding the expression of miRNAs in peripheral blood mononuclear cells (PBMCs) from Hashimoto's thyroiditis (HT) patients. Therefore, 38 HT patients and 36 healthy volunteers were enrolled in this study to identify HT-mediated changes in miRNA expression. Over 1,000 dysregulated miRNAs and their biological functions in the HT patients were identified. Among them, miR-125a-5p expression was upregulated and inversely correlated with low levels of MAF, a transcription factor that inhibits Th1 cells activity and the production of IFN-γ. Luciferase assay results demonstrated that MAF is a direct target gene of miR-125a-5p. Moreover, the proportion of circulating Th1 cells and the transcript levels of IFN-γ were increased in the HT patients. MiR-125a-5p expression positively correlated with the proportion of circulating Th1 cells and the serum concentrations of anti-thyroperoxidase antibodies in the HT patients. Interestingly, knockdown of miR-125a-5p in CD4⁺ T cells resulted in an elevated level of MAF but decreased the proportion of Th1 cells and the transcript level of IFN-γ in vitro. Furthermore, upregulated miR-125a-5p and IFN-γ transcript levels and downregulated MAF expression were detected in thyroid tissues from HT patients. Receiver operating characteristic (ROC) curves suggested that miR-125a-5p has a crucial role in the HT. Our results demonstrate that the elevated levels of miR-125a-5p contribute to the Th1 cells response in the HT patients and may be involved in the pathogenesis of HT.

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.

CircAP2A2 acts as a ceRNA to participate in infantile hemangiomas progression by sponging miR-382-5p via regulating the expression of VEGFA

Background

Increasing evidences reveal that circular RNAs (circRNAs) play crucial functions in cancer development. However, the expression pattern and roles of circRNAs in infantile hemangiomas (IH) remain unclear.

Methods

In this study, qRT‐PCR was performed to determine the expression of circAP2A2, miR‐382‐5p, and VEGFA in IH tissues and cell lines. Moreover, MTT assay, colony formation, transwell assay, and Western blot analysis were conducted to assess the function of circAP2A2 or miR‐382‐5p on cell proliferation, and migration in vitro, respectively. Also, dual luciferase assay was used to confirm the interactions among circAP2A2, miR‐382‐5p, and VEGFA.

Results

CircAP2A2 was confirmed to be highly expressed in IH. CircAP2A2 knockdown or miR‐382‐5p overexpression decreased the proliferation, colony formation, migration, and invasion of HemECs and HUVEC cells.

Conclusion

CircAP2A2 could promote proliferation and invasion of IH by regulating miR‐382‐5p/VEGFA axis.