Negative Correlation Between miR-326 and Ets-1 in Regulatory T Cells from new-Onset SLE Patients

LncRNA SNHG1 serves as a biomarker for systemic lupus erythematosus and participates in the disease progression

LncRNAs play an important role in autoimmune diseases. The purpose of this study was to explore the role of lncRNA SNHG1 in systemic lupus erythematosus (SLE), and laid a theoretical foundation for the study of SLE. The basic clinical information of all subjects was first collected for statistical analysis, and SNHG1 expression in the serum of all subjects was detected by RT-qPCR. The value of SNHG1 in the diagnosis of SLE was assessed by ROC. The correlation between SNHG1 and each blood sample index was analyzed by Pearson correlation analysis. The role of SNHG1 in primary peripheral blood mononuclear cells (PBMCs) apoptosis was explored. SNHG1 expression is relatively upregulated in patients with SLE compared to healthy people. SNHG1 expression was positively correlated with SLEDAI score, IgG, CRP, and ESR, and negatively correlated with C3 and C4. ROC indicated that SNHG1 has the potential to assist in the diagnosis of SLE. PBMCs apoptosis in SLE was higher than that in control group, the knockdown and overexpression of SNHG1 could correspondingly inhibit and promote PBMCs apoptosis. SNHG1 has the potential to be a diagnosis marker for SLE and may be involved in regulating PBMCs apoptosis.

MicroRNAs: Key modulators of inflammation-associated diseases

Inflammation is a multifaceted biological and pathophysiological response to injuries, infections, toxins, and inflammatory mechanisms that plays a central role in the progression of various diseases. MicroRNAs (miRNAs) are tiny, 19-25 nucleotides long, non-coding RNAs that regulate gene expression via post-transcriptional repression. In this review, we highlight the recent findings related to the significant roles of miRNAs in regulating various inflammatory cascades and immunological processes in the context of many lifestyle-related diseases such as diabetes, cardiovascular diseases, cancer, etc. We also converse on how miRNAs can have a dual impact on inflammatory responses, suggesting that regulation of their functions for therapeutic purposes may be disease-specific.

An update on the roles of transcription factor Ets1 in autoimmune diseases

Transcription factors are crucial to regulate gene expression in immune cells and in other cell types. In lymphocytes, there are a large number of different transcription factors that are known to contribute to cell differentiation and the balance between quiescence and activation. One such transcription factor is E26 oncogene homolog 1 (Ets1). Ets1 expression is high in quiescent B and T lymphocytes and its levels are decreased upon activation. The human ETS1 gene has been identified as a susceptibility locus for many autoimmune and inflammatory diseases. In accord with this, gene knockout of Ets1 in mice leads to development of a lupus-like autoimmune disease, with enhanced activation and differentiation of both B cells and T cells. Prior reviews have summarized functional roles for Ets1 based on studies of Ets1 knockout mice. In recent years, numerous additional studies have been published that further validate ETS1 as a susceptibility locus for human diseases where immune dysregulation plays a causative role. In this update, new information that further links Ets1 to human autoimmune diseases is organized and collated to serve as a resource. This update also describes recent studies that seek to understand molecularly how Ets1 regulates immune cell activation, either using human cells and tissues or mouse models. This resource is expected to be useful to investigators seeking to understand how Ets1 may regulate the human immune response, particularly in terms of its roles in autoimmunity and inflammation. This article is categorized under: Immune System Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Molecular and Cellular Physiology.

Regulation of activated T cell survival in rheumatic autoimmune diseases

Adaptive immune responses rely on the proliferation of T lymphocytes able to recognize and eliminate pathogens. The magnitude and duration of the expansion of activated T cell clones are finely regulated to minimize immunopathology and avoid autoimmunity. In patients with rheumatic autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis, activated lymphocytes survive and exert effector functions for prolonged periods, defying the mechanisms that normally curb their capacities during acute and chronic infections. Here, we review the molecular mechanisms that limit the duration of immune responses in health and discuss the factors that alter such regulation in the setting of systemic lupus erythematosus and rheumatoid arthritis. We highlight defects that could contribute to the development and progression of autoimmune disease and describe how chronic inflammation can alter the regulation of activated lymphocyte survival, promoting its perpetuation. These concepts might contribute to the understanding of the mechanisms that underlie the chronicity of inflammation in the context of autoimmunity.

Remote blast-related mild traumatic brain injury is associated with differential expression of exosomal microRNAs identified in neurodegenerative and immunological processes

BACKGROUND

Blast traumatic brain injury (TBI) and subconcussive blast exposure have been associated, pathologically, with chronic traumatic encephalopathy (CTE) and, clinically, with cognitive and affective symptoms, but the underlying pathomechanisms of these associations are not well understood. We hypothesized that exosomal microRNA (miRNA) expression, and their relation to neurobehavioral outcomes among Veterans with blunt or blast mild TBI (mTBI) may provide insight into possible mechanisms for these associations and therapeutic targets.

METHODS

This is a subanalysis of a larger Chronic Effects of Neurotrauma Consortium Biomarker Discovery Project. Participants (n = 152) were divided into three groups: Controls (n = 35); Blunt mTBI only (n = 54); and Blast/blast+blunt mTBI (n = 63). Postconcussive and post-traumatic stress symptoms were evaluated using the NSI and PCL-5, respectively. Exosomal levels of 798 miRNA expression were measured.

RESULTS

In the blast mTBI group, 23 differentially regulated miRNAs were observed compared to the blunt mTBI group and 23 compared to controls. From the pathway analysis, significantly dysregulated miRNAs in the blast exposure group correlated with inflammatory, neurodegenerative, and androgen receptor pathways.

DISCUSSION

Our findings suggest that chronic neurobehavioral symptoms after blast TBI may pathomechanistically relate to dysregulated cellular pathways involved with neurodegeneration, inflammation, and central hormonal regulation.

MicroRNAs and Diabetes Mellitus Type 1

Type 1 diabetes mellitus is a multifactorial, progressive, autoimmune disease with a strong genetic feature that can affect multiple organs, including the kidney, eyes, and nerves. Early detection of type 1 diabetes can help critically to avoid serious damages to these organs. MicroRNAs are small RNA molecules that act in post-transcriptional gene regulation by attaching to the complementary sequence in the 3'-untranslated region of their target genes. Alterations in the expression of microRNA coding genes are extensively reported in several diseases, such as type 1 diabetes. Presenting non-invasive biomarkers for early detection of type 1 diabetes by quantifying microRNAs gene expression level can be a significant step in biotechnology and medicine. This review discusses the area of microRNAs dysregulation in type 1 diabetes and affected molecular mechanisms involved in pancreatic islet cell formation and dysregulation in the expression of inflammatory elements as well as pro-inflammatory cytokines.

A Review of miR-326 and Female Related Diseases

MicroRNA (miRNA), a non-coding single-stranded RNA molecule with 20–23 nucleotides encoded by endogenous genes, plays an essential role in maintaining normal cell function and regulating cell proliferation, differentiation, apoptosis, autophagy, and cell metabolism. The imbalance between miRNA and genes can cause a series of diseases, including malignancies. miRNA-326 (miR-326) is extensively known for its core regulation of various biological processes. This review presents an overview of the highlights of miR-326 in female-related diseases. To understand the impact of miR-326 on female disorders, we search all published studies about miR-326 having a high incidence in female conditions, including cervical cancer, endometrial cancer, breast cancer, intrauterine adhesion, and multiple autoimmune diseases. We aim to learn about the mutual regulation mechanism between miR-326 and related genes and signaling pathways, as well as to elaborate on the value of miR-326 as a potential biomarker and therapeutic target of female diseases. Our results provide reliable evidence and new strategies for treating female tumors and autoimmune diseases.

In Vivo Inhibition of MicroRNA-326 in a NOD.H-2h4 Mouse Model of Autoimmune Thyroiditis

Background

Previous studies reported that various miRNAs participate in autoimmune diseases, but the potential regulatory mechanism of miRNAs in autoimmune thyroiditis (AIT) needs further exploration.

Objective

This study aimed to further verify that miR-326 contributes to AIT by regulating Th17/Treg balance through Ets-1 using lentiviral gene delivery through tail vein and thyroid injection in NOD.H-2^h4 mice.

Materials and Methods

Five-week-old NOD.H-2^h4 mice were divided randomly into tail vein and thyroid injection groups, and each received either mmu-miR-326 sponge (LV-sponge) or lentiviral vector control. Mice were divided for tail vein injection: the therapeutic LV-ctrl, therapeutic LV-sponge, prophylactic LV-ctrl, and prophylactic LV-sponge groups. The control group was fed high-iodine water without vein injection. The thyroid infiltration of lymphocytes and serum TgAb value were investigated by thyroid hematoxylin and eosin (HE) staining and ELISA, respectively. Ets-1 and lymphocyte counts were measured by RT-PCR, western blotting, and flow cytometry. The thyroid CD4⁺IL-17a⁺ cells and CD4⁺Ets-1⁺ cells were detected by immunofluorescence, and the serum cytokines were tested by ELISA.

Results

In the tail vein injection groups, the thyroid inflammatory score and serum TgAb titer were significantly lower in the LV-sponge groups than in the control and LV-ctrl groups while Ets-1 protein expression in mouse spleens was increased in the LV-sponge groups. Moreover, Th17/Treg ratio declined in the LV-sponge group and decreased significantly in the prophylactic LV-sponge group (P = 0.036) tested by flow cytometry. Immunofluorescence showed that, in LV-sponge groups, CD4⁺IL-17a⁺ cells were decreased significantly (P = 0.001), while CD4⁺Ets-1⁺ cells were increased significantly in the LV-sponge group (P = 0.029). The serum IL-17/IL-10 was decreased significantly in the LV-sponge group (P < 0.05). In the thyroid injection groups, the thyroid inflammatory score and serum TgAb titer in the LV-sponge group decreased significantly compared with those in the LV-ctrl group (P < 0.05). In addition, in LV-sponge groups, CD4⁺IL-17a⁺ cells were decreased, while CD4⁺Ets-1⁺ cells were increased significantly in the inhibition group evaluated by immunofluorescence. Moreover, tail vein injection of LV-sponge resulted in much lower TgAb levels in thyroiditis compared with thyroid injection.

Conclusion

MiR-326 targeted therapy may be a promising approach for AIT. In addition, tail vein injection may achieve a better intervention effect than thyroid injection.

IgGs-Abzymes from the Sera of Patients with Systemic Lupus Erythematosus Hydrolyzed miRNAs

Background and Objectives

Systemic lupus erythematosus (SLE) is an inflammatory disease. The sera of SLE patients contain antibodies-abzymes hydrolyzing myelin basic protein (MBP), DNA, nucleotides, and oligosaccharides. The blood of SLE patients contains an increased amount of some specific miRNAs. This study aimed to analyze a possible hydrolysis of eight microRNAs found in the blood of SLE patients with high frequency by blood antibodies-abzymes.

Patients and Methods

Using affinity chromatography of the serum proteins of SLE patients and healthy donors on protein G-Sepharose and following FPLC gel filtration, electrophoretically homogeneous IgG preparations containing no impurities of canonical RNases were obtained. These preparations were used to analyze their activity in the hydrolysis of eight miRNAs.

Results

It was shown that SLE IgGs hydrolyze very efficiently four neuroregulatory miRNAs (miR-219-2-3p, miR-137, miR-219a-5p, and miR-9-5p) and four immunoregulatory miRNAs (miR-326, miR-21-3p, miR-155-5p, and miR-146a-3p). To demonstrate that the miRNAs hydrolysis is an intrinsic property of SLE IgGs, several rigid criteria were checked. Only some IgGs of healthy donors showed very weak, but reliably detectable activity in the hydrolysis miRNAs. The average activity of SLE patients IgGs according to median values is statistically significant 84.8-fold higher than that of healthy donors. The maximum and comparable average activity (RA) was observed in the hydrolysis of three miRAs: miR-9-5p, miR-155-5p, and miR-326. MiR-9-5p plays an important role in the development of lupus nephritis, while miR-326 activates the production of antibodies by B cells. The major and moderate specific sites of the hydrolysis of each miRNA were revealed. The hydrolysis of eight microRNAs was mostly site specific. Several SLE IgGs hydrolyzed some miRNAs demonstrating a combination of site-specific and non-specific splitting.

Conclusion

Since inflammatory processes in SLE are associated with the change in miRNAs expression, the decrease in their concentration due to hydrolysis by autoantibodies-abzymes may be important for SLE pathogenesis.

miRNA Regulation of T Cells in Islet Autoimmunity and Type 1 Diabetes

PURPOSE OF REVIEW

Regulatory T cells (Tregs) are critical contributors to immune homeostasis and their dysregulation can lead to the loss of immune tolerance and autoimmune diseases like type 1 diabetes (T1D). Recent studies have highlighted microRNAs (miRNAs) as important regulators of the immune system, by fine-tuning relevant genes in various immune cell types. In this review article, we discuss recent insights into miRNA regulation of immune tolerance and activation. Specifically, we discuss how the dysregulation of miRNAs in T cells contributes to their aberrant function and the onset of islet autoimmunity, as well as their potential as targets of novel intervention strategies to interfere with autoimmune activation.

RECENT FINDINGS

Several studies have shown that the dysregulation of individual miRNAs in T cells can contribute to impaired immune tolerance, contributing to onset and progression of islet autoimmunity. Importantly, the targeting of these miRNAs, including miR-92a, miR-142-3p and miR-181a, resulted in relevant effects on downstream pathways, improved Treg function and reduced islet autoimmunity in murine models. miRNAs are critical regulators of immune homeostasis and the dysregulation of individual miRNAs in T cells contributes to aberrant T cell function and autoimmunity. The specific targeting of individual miRNAs could improve Treg homeostasis and therefore limit overshooting T cell activation and islet autoimmunity.

Non-Coding RNAs in CD4+ T Cells: New Insights Into the Pathogenesis of Systemic Lupus Erythematosus

Non-coding RNAs (ncRNAs) are indispensable for CD4⁺ T cell differentiation and functions. By directly or indirectly regulating immune gene expression, ncRNAs give flexible instructions to guide the biological processes of CD4⁺ T cells and play a vital role in maintaining immune homeostasis. However, the dysfunction of ncRNAs alters the gene expression profiles, disturbs the normal biological processes of CD4⁺ T cells, and leads to the functional changes of CD4⁺ T cells, which is an underlying cause of systemic lupus erythematosus (SLE). In this review, we focus on the recent advances in the roles of ncRNAs in CD4⁺ T cell functions and differentiation, as well as their potential applications in the diagnosis and treatment of SLE.

The Role of MicroRNAs in Regulatory T Cells

MicroRNAs are a class of conserved, 20 nt-23 nt long, noncoding small RNAs that inhibit expression of their respective target genes in different cell types. Regulatory T cells (Tregs) are a subpopulation of T cells that negatively regulate immune responses, which is essential to immune homeostasis. Recent studies have indicated that microRNAs play an important role in the proliferation, differentiation, and functions of Treg. Here, we review the recent progress in understanding the roles of microRNAs in Treg and their dysregulation in immune-related diseases. This ongoing research continues to expand the understanding of Treg regulation and the mechanisms of immune disorders.

miRNA-Mediated Immune Regulation in Islet Autoimmunity and Type 1 Diabetes

The important role of microRNAs as major modulators of various physiological processes, including immune regulation and homeostasis, has been increasingly recognized. Consequently, aberrant miRNA expression contributes to the defective regulation of T cell development, differentiation, and function. This can result in immune activation and impaired tolerance mechanisms, which exert a cardinal function for the onset of islet autoimmunity and the progression to T1D. The specific impact of miRNAs for immune regulation and how miRNAs and their downstream targets are involved in the pathogenesis of islet autoimmunity and T1D has been investigated recently. These studies revealed that increased expression of individual miRNAs is involved in several layers of tolerance impairments, such as inefficient Treg induction and Treg instability. The targeted modulation of miRNAs using specific inhibitors, resulting in improved immune homeostasis, as well as improved methods for the targeting of miRNAs, suggest that miRNAs, especially in T cells, are a promising target for the reestablishment of immune tolerance.

The pathogenesis of systemic lupus erythematosus: Harnessing big data to understand the molecular basis of lupus

Systemic lupus erythematosus (SLE) is a chronic, systemic autoimmune disease that causes damage to multiple organ systems. Despite decades of research and available murine models that capture some aspects of the human disease, new treatments for SLE lag behind other autoimmune diseases such as Rheumatoid Arthritis and Crohn's disease. Big data genomic assays have transformed our understanding of SLE by providing important insights into the molecular heterogeneity of this multigenic disease. Gene wide association studies have demonstrated more than 100 risk loci, supporting a model of multiple genetic hits increasing SLE risk in a non-linear fashion, and providing evidence of ancestral diversity in susceptibility loci. Epigenetic studies to determine the role of methylation, acetylation and non-coding RNAs have provided new understanding of the modulation of gene expression in SLE patients and identified new drug targets and biomarkers for SLE. Gene expression profiling has led to a greater understanding of the role of myeloid cells in the pathogenesis of SLE, confirmed roles for T and B cells in SLE, promoted clinical trials based on the prominent interferon signature found in SLE patients, and identified candidate biomarkers and cellular signatures to further drug development and drug repurposing. Gene expression studies are advancing our understanding of the underlying molecular heterogeneity in SLE and providing hope that patient stratification will expedite new therapies based on personal molecular signatures. Although big data analyses present unique interpretation challenges, both computationally and biologically, advances in machine learning applications may facilitate the ability to predict changes in SLE disease activity and optimize therapeutic strategies.

Integrated analysis of lncRNA, miRNA and mRNA expression profiling in patients with systemic lupus erythematosus

INTRODUCTION

A great deal of research has reported dysregulated expression of genes in systemic lupus erythematosus (SLE). This study aimed to analyze the lncRNA, miRNA and mRNA expression profile in SLE.

MATERIAL AND METHODS

RNA sequencing (RNA-seq) was used to detect the dysregulated RNAs in SLE. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis were used to explore the function of these differentially expressed RNAs.

RESULTS

2,353 lncRNAs, 827 mRNAs and 24 miRNAs were shown to be differentially expressed. GO analyses demonstrated that differentially expressed RNAs were enriched in a variety of molecular functions and biological processes including ribonucleotide, protein serine/threonine kinase activity function, regulation of B cell differentiation and others. KEGG pathway analyses revealed that differentially expressed mRNAs and lncRNAs were both enriched in FcγR-mediated phagocytosis, glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate and glyoxylate and dicarboxylate metabolism pathways. The up-regulated miRNAs target genes were mainly enriched in the nuclear factor-κB (NF-κB) signaling pathway. The down-regulated miRNAs target genes were significantly enriched in metabolism of xenobiotics by cytochrome P450, bile secretion and terpenoid backbone biosynthesis pathways.

CONCLUSIONS

The current study reveals a comprehensive expression profile of lncRNAs, miRNAs and mRNAs and implies potential regulatory functions of these RNAs which are involved in the pathogenesis of SLE.

Increased levels of adipose tissue-resident Th17 cells in obesity associated with miR-326

miRNAs are important immune regulators in the control of the CD4 + T cells phenotype. miR-326 regulates the differentiation towards Th17 cells and the inhibition of miR-155 is associated with low levels of Treg cells. However, miRNAs expression and transcription factors associated with these lymphocyte subsets in obesity-induced adipose tissue inflammation is still unknown. The aim of this work was to identify Th17 cells in subcutaneous adipose tissue (SAT), proinflammatory cytokine production and their association with the miRNAs and transcription factors involved. We collected SAT samples obtained by lipoaspiration from individuals with normal weight, overweight and obesity. We obtained the stromal vascular fractions and then a Ficoll gradient was performed to obtain adipose tissue mononuclear cells (ATMC). Th17 cells were evaluated by flow cytometry and the expression of miR-326, miR-155, RORC2 and FOXP3 by qRT-PCR. We also analyzed cytokines from the supernatants of the ATMC culture and measured the FOXP3 methylation percentage by bisulfite conversion by PCR. According to the results, the frequency of Th17 cells and RORC2 expression was higher in individuals with obesity and associated with miR-326 expression. The ATMC from this group secreted a proinflammatory cytokine profile by in vitro assay. In contrast, lower levels of mRNA FOXP3 expression was detected in ATMC from individuals with obesity that correlated with methylation percentage of FOXP3 gene but no association with miR-155 was detected. Our results suggested that miR-326 participates in the polarization towards Th17 promoting the inflammatory state in the obesity-induced adipose tissue.

MicroRNA-326-3p ameliorates high glucose and ox-LDL-IC- induced fibrotic injury in renal mesangial cells by targeting FcγRIII

AIM

The aim of the present study was to identify the regulatory relationship between miR-326-3p and FcγRIII, and to explore the involvement of miR-326-3p/FcγRIII/TGF-β/Smad signalling pathway in fibrotic injury, which was induced by the high glucose (HG) and oxidized low density lipoprotein immune complex (ox-LDL-IC) in mouse glomerular mesangial cells (GMCs).

METHODS

Dual-luciferase reporter system and real time PCR (RT-PCR) were used to identify FcγRIII as a target gene of miR-326-3p. Lentiviral transduction was used to construct different expression of miR-326-3p in GMCs, which were divided into three groups: miR-326-3p mimics group (miR-326-3p group), miR-326-3p inhibitor group (miR-326-3p-inhibit group) and scramble control group (control group). Then, each group was stimulated by normal glucose (NG), HG, ox-LDL-IC and HG + ox-LDL-IC, respectively. RT-PCR and western blot were used to measure the expressions of Col-I, CTGF, α-SMA, TGF-β, Smad2/3 and pSmad2/3.

RESULTS

FcγRIII was regulated negatively by miR-326-3p in GMCs under the condition of HG and ox-LDL-IC, which implied FcγRIII as a target gene of miR-326-3p. Furthermore, compared with normal glucose group, the expressions of Col-I, CTGF, α-SMA, TGF-β and pSmad2/3 were higher under the condition of HG, ox-LDL-IC and HG + ox-LDL-IC (P < 0.05). In particular, miR-326-3p-inhibit groups exhibited the most significant increase (P < 0.05), while miR-326-3p could attenuate the increase (P < 0.05).

CONCLUSION

FcγRIII was identified as a target gene of miR-326-3p. MiR-326-3p/FcγRIII/TGF-β/Smad signaling pathway was investigated to be involved in the pathophysiology of renal fibrosis of DKD.

The potential role of Ets-1 and miR-326 in CD19+B cells in the pathogenesis of patients with systemic lupus erythematosus

OBJECTIVES

The aim of this study was to investigate the B cell-associated transcription factors, Ets-1 and microRNA, miR-326 in systemic lupus erythematosus (SLE) patients, and their correlation with the pathogenesis of SLE.

METHOD

A total of 44 SLE patients and 20 healthy controls were enrolled in this research, all patients fulfilled the American College of Rheumatology classification criteria for SLE. The mRNA expression of Ets-1 and miR-326 in CD19⁺B cells from SLE patients were examined by qRT-PCR. The percentages of CD19⁺CD138⁺plasma cells were analyzed by Flow cytometry.

RESULTS

We found decreased expression of Ets-1 mRNA in SLE patients compared with the healthy controls ([0.228 (0.145, 0.507)] vs [0.583 (0.452, 0.763)], p = 0.001),while increased expression of miR-326 mRNA in CD19⁺B cells SLE patients compared with the healthy controls([1.092 (0.457, 2.855)] vs [0.685 (0.274, 0.819)], p = 0.008). The percentage of CD19⁺CD138⁺plasma cells in SLE patients was higher than that of healthy controls (0.55 ± 0.21% vs 0.36 ± 0.21%, p = 0.002). Moreover, a negative correlation between expression of Ets-1 mRNA and miR-326 mRNA in CD19⁺B cells was detected (r = - 0.334, p = 0.027). A significant association between the occurrences of CD19⁺CD138⁺plasma cells and the levels of Ets-1 mRNA and miR-326 mRNA was observed (r = - 0.417, p = 0.005 and r = 0.482, p = 0.001, respectively).

CONCLUSIONS

Our results suggest that miR-326 might promote B cells differentiation by targeting Ets-1, a negative regulator of B cells differentiation and therefore participate in the pathogenesis of SLE.

MicroRNAs in Autoimmunity and Hematological Malignancies

Autoimmunity and hematological malignancies are often concomitant in patients. A causal bidirectional relationship exists between them. Loss of immunological tolerance with inappropriate activation of the immune system, likely due to environmental and genetic factors, can represent a breeding ground for the appearance of cancer cells and, on the other hand, blood cancers are characterized by imbalanced immune cell subsets that could support the development of the autoimmune clone. Considerable effort has been made for understanding the proteins that have a relevant role in both processes; however, literature advances demonstrate that microRNAs (miRNAs) surface as the epigenetic regulators of those proteins and control networks linked to both autoimmunity and hematological malignancies. Here we review the most up-to-date findings regarding the miRNA-based molecular mechanisms that underpin autoimmunity and hematological malignancies.

The imbalance of Th17/Treg axis involved in the pathogenesis of preeclampsia

PROBLEM

Inappropriate activation of the immune system, particularly the imbalance of T-helper type 17 (Th17)/regulatory T (Treg) cells is thought to play considerable roles in preeclampsia (PE). To investigate the probable effects of the adaptive immune system in the pathophysiology of PE, we analyzed the dynamic changes of Th17/Treg cells, cytokines profile, and transcription pattern of Th17/Treg-related genes and microRNAs (miRNAs) in 50 women suffering from PE in comparison with 50 healthy pregnant women.

METHODS

Expressions of cytokines, specific transcription factors, and related miRNAs were measured by real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was used to test the interleukin (IL)-17, IL-23, IL-6, and IL-10 and transforming growth factor β in serum and supernatant of peripheral blood mononuclear cells (PBMCs). The frequency of Th17 and Treg cells were determined by flow cytometry.

RESULTS

PE patients exhibited a decreased number of Treg cells (p = 0.006), while Th17 cells were increased ( p = 0.004). Forkhead box P3 and IL-10 mRNA expressions were reduced ( p = 0.0001 and 0.0028, respectively), while expressions of retinoic acid receptor-related orphan nuclear receptor γt, IL-17, IL-23, and IL-6 were enhanced ( p < 0.0001, 0.0018, 0.0014, and 0.027, respectively). ELISA results also showed increased levels of IL-6, IL-17, and IL-23 ( p = 0.022, 0.0005, 0.0081, respectively), and decreased levels of IL-10 in the supernatant of PBMCs of PE patients compared with control group ( p = 0.0011). There was significant upregulation of miR-106b and miR-326 ( p = 0.0048 and 0.028, respectively) in PE patients in comparison with the control group.

CONCLUSIONS

These findings suggest that imbalance of Th17/Treg cells, regulated possibly via microRNAs, may be involved in the pathogenesis of PE, emphasizing on the importance of these cells in feto-maternal immune cross-talk.

MicroRNA-mediated regulation of T helper type 17/regulatory T-cell balance in autoimmune disease

T helper type 17 (Th17) cells and regulatory T (Treg) cells are two distinct T-cell subsets with opposite effects on immune functions. While Th17 cells are a key effector in the immune response and play critical roles in the development of autoimmunity and inflammation, Treg cells orchestrate the overall immune response and maintain peripheral immune tolerance by regulating the activity of the effector T cells. However, the developmental pathways for Th17 and Treg cells are reciprocally interconnected and there is a significant amount of plasticity between them. Disturbed Th17/Treg balance contributes to the development of autoimmune diseases, like experimental autoimmune encephalomyelitis and multiple sclerosis. MicroRNAs (miRNAs) are small non-coding RNA molecules that post-transcriptionally regulate gene expression. Recently, emerging evidence demonstrates that miRNAs play an important role in regulating the pathogenesis of autoimmune diseases through the modulation of Th17/Treg balance. This review will provide an overview of the dysregulated miRNAs and their functions in modulating the Th17/Treg balance in autoimmune diseases.

Increased expression of microRNAs, miR-20a and miR-326 in PBMCs of patients with type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disorder which is characterized by autoimmune attack on β cells of pancreas and lack of insulin. The involvement of microRNAs (miRNAs) in the development of immune system and their differential expression in various autoimmune diseases including T1D have been well established. In this study, the association between expression levels of miR-20a, miR-326 and T1D were evaluated. The expression levels of miR-20a and miR-326 were measured in the PBMCs of 21 T1D patients and 16 healthy controls using qPCR method. In silico analysis was also performed on targetome of miR-20a and miR-326. Both miR-20a (p value: 0.015) and miR-326 (p value: 0.005) were upregulated in the PBMCs of T1D patients compared to healthy controls. Furthermore, different dysregulated miR326-mRNA and miR20a-mRNA interactions were also suggested using integrative computational analysis. The expression level of miR-20a and miR-326 indicates significant association with T1D which suggests the possible regulatory effects of these non-coding RNAs in T1D.

The MicroRNA-326: Autoimmune diseases, diagnostic biomarker, and therapeutic target

MicroRNAs (miRNAs) are uniquely regulated in healthy, inflamed, activated, cancerous, or other cells and tissues of a pathological state. Many studies confirm that immune dysregulation and autoimmune diseases with inflammation are correlated with various miRNA expression changes in targeted tissues and cells in innate or adaptive immunity. In this review, we will explain the history and classification of epigenetic changes. Next, we will describe the role of miRNAs changes, especially mir-326 in autoimmunity, autoinflammatory, and other pathological conditions. A systematic search of MEDLINE, Embase, and Cochrane Library was presented for all related studies from 1899 to 2017 with restrictions in the English language. In recent years, researchers have concentrated on mostly those roles of miRNA that are correlated with the inflammatory and anti-inflammatory process. Latest studies have proposed a fundamental pathogenic role in cancers and autoinflammatory diseases. Studies have described the role of microRNAs in autoimmunity and autoinflammatory diseases, cancers, and so on. The miRNA-326 expression plays a significant role in autoimmune and other types of diseases.

MicroRNA-mediated immune regulation in rheumatic diseases

MicroRNAs (miRNAs) are endogenous small, non-coding RNAs that regulate genome expression at the post-transcriptional level. They are involved in a wide range of physiological processes including the maintenance of immune homeostasis and normal function. Accumulating evidence from animal studies show that alterations in pan or specific miRNA expression would break immunological tolerance, leading to autoimmunity. Differential miRNA expressions have also been documented in patients of many autoimmune disorders. In this review, we highlight the evidence that signifies the critical role of miRNAs in autoimmunity, specifically on their regulatory roles in the pathogenesis of several rheumatic diseases including systemic lupus erythematosus, rheumatoid arthritis and spondyloarthritis. The potential of miRNAs as biomarkers and therapeutic targets is also discussed. Manipulation of dysregulated miRNAs in vivo through miRNA delivery or inhibition offers promise for new therapeutic strategies in treating rheumatic diseases.

MicroRNA-326 Upregulates B Cell Activity and Autoantibody Production in Lupus Disease of MRL/lpr Mice

B cells are recognized as key participants in various autoimmune diseases, including systemic lupus erythematosus (SLE). Although sets of transcription factors and cytokines are known to regulate B cell differentiation, the roles of microRNAs are poorly understood. Our previous study proved that microRNA-326 (miR-326) was markedly upregulated in SLE patients; however, the biological function of miR-326 during SLE pathogenesis remained unknown. In this study, we found that miR-326 overexpression in MRL/lpr mice led to B cell hyperactivity and severe SLE. Moreover, E26 transformation-specific-1 (Ets-1), a negative regulator of B cell differentiation, was identified as a target of miR-326. Therefore, a novel mechanism has been found in which the elevated miR-326 in B cells of SLE promotes plasmablast development and antibody production through downregulation of Ets-1.

MicroRNA-326 contributes to autoimmune thyroiditis by targeting the Ets-1 protein

PURPOSE

MicroRNA-326 (miR-326), as a member of the microRNA (miRNA) family, which includes endogenous single-stranded, conserved, noncoding small RNAs, has been reported to play important roles in autoimmune diseases such as multiple sclerosis and systemic lupus erythematosus. However, few studies of the role of miR-326 in autoimmune thyroiditis (AIT) have been published. Here, we explored the roles of miR-326 and the involved pathway in iodine-induced AIT.

METHODS

NOD.H-2^h4 mice, which are a model of human AIT, were randomly divided into a normal water control group and a high-iodine group. Mice in the high-iodine group were administered 0.05% NaI (~1000 times the normal daily iodine intake), and mice in the control group received sterile water. Furthermore, we evaluated small interfering RNA (siRNA) interference in spleen mononuclear cell experiments in vitro.

RESULTS

In this study, we found that Th17 cells were significantly increased with a high expression of miR-326 in an iodine-induced thyroiditis NOD.H-2^h4 mouse model. In addition, the expression of Ets-1 protein, a negative regulator of Th17 differentiation, was significantly decreased. Intriguingly, our analysis showed that Ets-1 protein expression was negatively correlated with miR-326 levels in AIT mice (r = -0.814, p < 0.01). Our study indicated that miR-326 inhibited Ets-1 protein expression and promoted the differentiation of Th17 cells during the onset and development of AIT. The addition of a miR-326 inhibitor reversed Th17 cell production and Ets-1 protein expression, supporting this hypothesis.

CONCLUSIONS

The results of our study suggest that miR-326 may target the Ets-1 protein to contribute to iodide-induced thyroiditis, providing a new theoretical basis for the use of miRNA targeting therapy for the treatment of autoimmune diseases.

Extracellular miR-145, miR-223 and miR-326 expression signature allow for differential diagnosis of immune-mediated neuroinflammatory diseases

BACKGROUND

Although misdiagnosis of neuromyelitis optica spectrum disorder (NMOSD) with neuropsychiatric systemic lupus erythematosus (NPSLE) or multiple sclerosis (MS) is not infrequent, reliable biomarkers remains an unmet need. Extracellular microRNAs (miRNAs) represent a worthy avenue to identify biomarkers for differential diagnosis. We aimed to explore the potential role of some selected circulating miRNAs as biomarkers for the differential diagnosis in immune-mediated neuroinflammatory diseases.

METHODS

A total of 80 subjects were enrolled in the present study, including 37 patients with MS (relapsing-remitting MS [RRMS; n=18] and secondary progressive MS [SPMS; n=19]), 10 patients with NMOSD and 10 patients with NPSLE as well as 23 healthy subjects. Serum expression levels of three selected miRNAs (miR-145, miR-223 and miR-326) were measured using quantitative real-time polymerase chain reaction (qRT-PCR). Whole blood expression levels of cellular immune response-relevant target genes, including signaling mother against decapentaplegic peptide 3 (SMAD3) and specificity protein 1 (SP1), were also measured using qRT-PCR.

RESULTS

In comparison to healthy subjects, only miR-145 and miR-223 were significantly up-regulated in MS patients, whereas, all the analyzed miRNAs revealed insignificant upregulation in NMOSD patients. All the examined miRNAs were significantly down-regulated in NPSLE patients compared to healthy subjects. miR-145, miR-223 and miR-326 expression profile is a promising diagnostic biomarker for MS and NPSLE, but not for NMOSD. This expression profile is capable of differentiating not only among MS, NMOSD and NPSLE, but also between RRMS and SPMS.

CONCLUSION

Specific circulating miRNAs expression signature may have the potential to differentially diagnose immune-mediated neuroinflammatory diseases.

Translating epigenetics into clinic: focus on lupus

Systemic lupus erythematosus (SLE) is a chronic relapsing–remitting autoimmune disease with highly heterogeneous phenotypes. Biomarkers with high sensitivity and specificity are useful for early diagnosis as well as monitoring disease activity and long-term complications. Epigenetics potentially provide novel biomarkers in autoimmune diseases. These may include DNA methylation changes in relevant lupus-prone genes or histone modifications and microRNAs to upregulate and downregulate relevant gene expression. The timing and nature of epigenetic modification provide such changes. In lupus, DNA methylation alterations in cytokine genes, such as IFN-related gene and retrovirus gene, have been found to offer biomarkers for lupus diagnosis. Histone modifications such as histone methylation and acetylation lead to transcriptional alterations of several genes such as PTPN22, LRP1B, and TNFSF70. There are varieties of microRNAs applied as lupus biomarkers, including DNMT1-related microRNAs, renal function-associated microRNAs, microRNAs involved in the immune system, and microRNAs for phenotype classification. Thus, we conclude a wide range of promising roles of epigenetic biomarkers aiding in the diagnosing and monitoring of lupus diseases and the risk of organ damage.