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

MiR-326 sponges TET2 triggering imbalance of Th17/Treg differentiation to exacerbate pyroptosis of hepatocytes in concanavalin A-induced autoimmune hepatitis

INTRODUCTION AND OBJECTIVES

MicroRNA-326 is abnormally expressed in autoimmune diseases, but its roles in autoimmune hepatitis (AIH) are unknown. In this study, we aimed to investigate the effect of miR-326 on AIH and the underlying mechanism.

MATERIALS AND METHODS

Concanavalin A was administrated to induce AIH in mice and the expression levels of miR-326 and TET2 was evaluated by qRT-PCR and western blot, respectively. The percentages of Th17 and Treg cells were evaluated by flow cytometry and their marker proteins were determined by western blot and ELISA. The mitochondrial membrane potential (MMP) and ROS level were tested with the JC-1 kit and DCFH-DA assay. The binding relationships between miR-326 and TET2 were verified by dual-luciferase reporter assay. The liver tissues were stained by the HE staining. In vitro, AML12 cells were cocultured with mouse CD4+T cells. The expression levels of pyroptosis-related proteins were assessed by western blot.

RESULTS

Concanavalin A triggered AIH and enhanced the expression level of miR-326 in mice. It increased both Th17/Treg ratio and the levels of their marker proteins. The expression of TET2 was decreased in AIH mice. Knockdown of miR-326 could decrease the levels of pyroptosis-related proteins, the ROS level and increase MMP. In mouse CD4+T cells, miR-326 sponged TET2 to release IL-17A. Coculture of AML12 cells with isolated CD4+T cells from miR-326 knockdown AIH mice could relieve pyroptosis.

CONCLUSIONS

Knockdown of miR-326 exerted anti-pyroptosis effects via suppressing TET2 and downstream NF-κB signaling to dampen AIH. We highlighted a therapeutic target in AIH.

Pathogenic role of Th17 cells in autoimmune thyroid disease and their underlying mechanisms

Autoimmune thyroid disease, encompassing Graves' disease and Hashimoto's thyroiditis, has a very complex etiology. Pathogenesis of the disease involves both genetic susceptibility and environmental triggers. Traditionally, imbalance of T helper cell 1 and 2 was thought to result in the immune disorders in Graves' disease and Hashimoto's thyroiditis. However, increasing evidence recently revealed the important role of T helper 17 cell and its relative cellular and secretory components in the pathogenesis and progression of autoimmune thyroid disease. This review is aimed to summarize the published studies on the involvement of T helper 17 cell in autoimmune thyroid disease and discuss the underlying regulatory mechanisms, which could possibly serve as the foundation of discovering new therapeutic targets.

B Cell Activation Results in IKK-Dependent, but Not c-Rel- or RelA-Dependent, Decreases in Transcription of the B Cell Tolerance-Inducing Gene Ets1

Ets1 is a key transcription factor in B cells that is required to prevent premature differentiation into Ab-secreting cells. Previously, we showed that BCR and TLR signaling downregulate Ets1 levels and that the kinases PI3K, Btk, IKK, and JNK are required for this process. PI3K is important in activating Btk by generating the membrane lipid phosphatidylinositol (3,4,5)-trisphosphate, to which Btk binds via its PH domain. Btk in turn is important in activating the IKK kinase pathway, which it does by activating phospholipase Cγ2→protein kinase Cβ signaling. In this study, we have further investigated the pathways regulating Ets1 in mouse B cells. Although IKK is well known for its role in activating the canonical NF-κB pathway, IKK-mediated downregulation of Ets1 does not require either RelA or c-Rel. We also examined the potential roles of two other IKK targets that are not part of the NF-κB signaling pathway, Foxo3a and mTORC2, in regulating Ets1. We find that loss of Foxo3a or inhibition of mTORC2 does not block BCR-induced Ets1 downregulation. Therefore, these two pathways are not key IKK targets, implicating other as yet undefined IKK targets to play a role in this process.

Elevated interleukin-17A levels despite reduced microRNA-326 gene expression in celiac disease patients under gluten-free diet

Introduction: The microRNA-326 (miR-326) gene, by targeting ETS Proto-Oncogene 1 (ETS1), regulates the differentiation and interleukin-17A production of T helper 17 (Th17) cells. Celiac disease (CD) is an intestinal autoimmune disorder, in which the cascade of Th17 cells plays an important role in its pathogenicity. The aim of this study was to evaluate the expression changes of miR-326 and its two target genes ETS1 and IL-17A in celiac disease patients under a gluten-free diet (GFD). We expected the expression of miR-326 and IL-17A gene to decrease, and the expression of the ETS1 gene to increase, following the adherence to GFD.

Methods: Peripheral blood samples of 40 CD patients under GFD (for more than 1 year) and 40 healthy individuals were collected. RNA was extracted, cDNA was synthesized and the miR-326, ETS1 and IL-17A gene expressions were evaluated by the quantitative polymerase real-time qPCR method. P-value ˂ 0.05 was considered statistically significant.

Results: Although miR-326 mRNA expression was significantly lower in CD patients (P = 0.001), no significant difference was observed in ETS1 mRNA level between the two groups (P = 0.54), but IL-17A was significantly overexpressed in CD patients (P=0.002). No significant correlation was observed between the expression of the studied genes and the patientsʼ symptoms and Marsh classification.

Conclusion:Adherence to the GFD for one to two years did not have the expected effect on the expression of genes in this panel. The most important finding that contradicted our hypothesis was the observation of high IL-17A levels in CD patients despite dieting, which may be related to the protective effect of this cytokine on intestinal tight junctions, which needs to be confirmed in further studies.

Spironolactone alleviates myocardial fibrosis via inhibition of Ets‑1 in mice with experimental autoimmune myocarditis

Spironolactone improves cardiac structure, function and prognosis in patients with heart failure and delays the progression of cardiac fibrosis. However, the exact underlying mechanism of this process remains to be elucidated. The present study therefore aimed to explore the protective effect and underlying mechanism of the aldosterone receptor antagonist, spironolactone, on myocardial fibrosis in mice with experimental autoimmune myocarditis (EAM). The EAM model was induced in BALB/c mice via immunization with murine cardiac α-myosin heavy chain sequence polypeptides. The cardiac function of the mice was assessed using echocardiography and the levels of inflammatory cytokines were quantified using ELISA. E26 transformation-specific sequence-1 (Ets-1) expression was knocked down using lentivirus-mediated small interference RNA. Total collagen deposition was assessed using Masson's trichrome and Ets-1, TGF-β1, Smad2/3, collagen I and III protein expression levels were detected using immunohistochemistry and western blotting. MMP-2 and MMP-9 mRNA expression levels and activity was determined using reverse transcription-quantitative PCR and gelatin zymography, respectively. The results of the present study demonstrated that spironolactone significantly improved myocardium hypertrophy, diastolic cardiac function and decreased myocardial inflammation and collagen deposition induced by EAM. Spironolactone treatment significantly inhibited Ets-1 and smad2/3 phosphorylation. In addition, inhibition of Ets-1 reduced the expression and activity of MMP-2 and MMP-9 and decreased cardiac fibrosis in EAM mice. The results indicated that the improvement of myocardial fibrosis by spironolactone may be associated with the TGF-β1/Smad-2/3/Ets-1 signaling pathway in EAM mice.

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.

Upregulated microRNA-132 in T helper 17 cells activates hepatic stellate cells to promote hepatocellular carcinoma cell migration in vitro

MicroRNAs play an important role in the modulation of the immune system. T helper 17 (Th17) cells are involved in the modulation of the tumour microenvironment. However, the function of miRNA in Th17 cells in the tumour microenvironment is unclear. In this study, we analysed miR-132 expression in Th17 cells and assessed the function of miR-132 on Th17 cell differentiation. In addition, the effect of miR-132 on Th17 cells in the tumour microenvironment, especially hepatic stellate cells (HSCs), was confirmed. CD4+ IL-17 ∓ cells were isolated from hepatocellular carcinoma (HCC) tumour tissues. The expression of miR-132 was higher in CD4+ IL-17 + cells than in CD4+ IL-17- cells. Human primary CD4+ T cells were used for Th17 cell differentiation. Compared with primary CD4+ T cells, Th17 cells expressed high levels of miR-132. During Th17 cell differentiation, a miR-132 mimic and inhibition were applied. After treatment with the miR-132 mimic, the differentiation of Th17 cells accelerated, showing a a higher percentage of Th17 cells and the expression and secretion of IL-17 and IL-22. Smad nuclear interacting protein 1 (SNIP1), as one of the targets of miR-132, decreased during Th17 cell differentiation-related Th17 differentiation and IL-17 expression. The conditioned medium of miR-132-overexpressing Th17 cells could increase the activation of the HSCs, which strongly promoted HCC cell migration and epithelial-mesenchymal transition (EMT). In summary, miR-132 positively regulates Th17 cell differentiation and improves the function of Th17 on HSCs for their tumour-promoting effects.

miRNAs Alter T Helper 17 Cell Fate in the Pathogenesis of Autoimmune Diseases

T helper 17 (Th17) cells are characterized by the secretion of the IL-17 cytokine and are essential for the immune response against bacterial and fungal infections. Despite the beneficial roles of Th17 cells, unrestrained IL-17 production can contribute to immunopathology and inflammatory autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Although these diverse outcomes are directed by the activation of Th17 cells, the regulation of Th17 cells is incompletely understood. The discovery that microRNAs (miRNAs) are involved in the regulation of Th17 cell differentiation and function has greatly improved our understanding of Th17 cells in immune response and disease. Here, we provide an overview of the biogenesis and function of miRNA and summarize the role of miRNAs in Th17 cell differentiation and function. Finally, we focus on recent advances in miRNA-mediated dysregulation of Th17 cell fate in autoimmune diseases.

Elevated MicroRNA-326 Levels Regulate the IL-23/IL-23R/Th17 Cell Axis in Hashimoto's Thyroiditis by Targeting a Disintegrin and Metalloprotease 17

Background: MicroRNAs (miRNAs) are a class of critical epigenetic regulators involved in several autoimmune diseases. Our previous study reported an miR-326-induced increase in T helper (Th) 17 cells in a mouse model of Hashimoto's thyroiditis (HT), but the pathogenic effect of miR-326 in HT patients has not been verified. The goal of the present study was to explore the pathogenic role of miR-326 and its underlying molecular mechanism in HT patients. Methods: A total of 58 HT patients and 55 normal controls were enrolled in this study. We examined whether Th17 cells and miR-326 were aberrantly altered in the peripheral blood mononuclear cells (PBMCs) of HT patients with flow cytometry and real-time polymerase chain reaction. Levels of membrane interleukin (IL)-23R (mIL-23R) were determined by flow cytometry and Western blot to explore the critical role of mIL-23R in the development of Th17 cells. Isolated CD3⁺ T cells were used to further investigate the ectodomain shedding of mIL-23R by a disintegrin and metalloprotease (ADAM17). Furthermore, miR-326 inhibitor and mimics were transfected into PBMCs derived from HT patients and healthy controls to verify the regulation of ADAM17 by miR-326. Results: We observed elevated miR-326 levels in the PBMCs of HT patients compared with those in the PBMCs of healthy controls. Consistent with IL-23-induced STAT3 overactivation, substantially more HT patient-derived PBMCs differentiated into Th17 cells under polarization culture conditions, which may, at least in part, have resulted from enhanced mIL-23R levels. Furthermore, ADAM17, an ectodomain sheddase of mIL-23R, was targeted and negatively regulated by miR-326. Inhibiting ADAM17 might attenuate the ectodomain shedding of mIL-23R. Conclusions: Our findings suggest that the effect of miR-326 on the IL-23/IL-23R/Th17 cell axis in HT patients might be partially due to the targeting of ADAM17.

Emerging Roles for Noncoding RNAs in Autoimmune Thyroid Disease

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

High iodine induces DNA damage in autoimmune thyroiditis partially by inhibiting the DNA repair protein MTH1

This study aims to investigate the level of DNA damage in high iodine (HI)-induced autoimmune thyroiditis (AIT), and to explore the role of DNA repair protein MutT homolog-1 (MTH1) in this process. The levels of pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 were measured using qRT-PCR and ELISA. The apoptosis was evaluated using TUNEL staining. The pathological changes of thyroid tissues were evaluated using hematoxylin and eosin (HE) staining. The DNA damage was assessed by determining the expression of 8-hydroxy-2'deoxyguanosine (8-OHdG; an indicator of oxidative DNA damage) and performing the Comet assay. Our results showed that both the HI-treated NOD.H-2^h4 mice (experimental AIT mice) and the HI-treated mouse thyroid follicular epithelial cells showed enhanced inflammation, apoptosis, and DNA damage level, accompanied by decreased MTH1 expression. Importantly, overexpression of MTH1 effectively abrogated the HI-induced enhancement of inflammation, apoptosis, and DNA damage in mouse thyroid follicular epithelial cells. In conclusion, HI treatment induces DNA damage in AIT, at least in part, by inhibiting the DNA repair protein MTH1.

Intravitreal Ets1 siRNA alleviates choroidal neovascularization in a mouse model of age-related macular degeneration

Choroidal neovascularization (CNV) is the basic feature of neovascular age-related macular degeneration (AMD), the leading cause of blindness in elders. Macrophages and microglia promote CNV via producing pro-angiogenic factors and inflammatory cytokines. Transcription factor E26 transformation specific-1 (Ets1) plays a pro-angiogenic role via its pro-inflammatory function. In this study, Ets1 increased and localized in the macrophages and microglia of a mouse laser-induced CNV region. Ets1 siRNA intravitreal injection ameliorated the leakage and area of CNV, as well as inhibiting the dysfunction of retinal pigment epithelium (RPE) cells and the activation of macrophages/microglia. Taken together, we provide a new insight into the molecular mechanism of CNV progression, in which Ets1 can be a new therapeutic target.