miR-20b suppresses Th17 differentiation and the pathogenesis of experimental autoimmune encephalomyelitis by targeting RORγt and STAT3

JAK2/STAT3 Pathway Inhibition by AG490 Ameliorates Experimental Autoimmune Encephalomyelitis via Regulation of Th17 Cells and Autophagy

Multiple sclerosis (MS) is an autoimmune inflammatory condition affecting the central nervous system, and experimental autoimmune encephalomyelitis (EAE) animal models have been extensively used to study it. T-helper 17 cells, which produce interleukin-17(IL-17), play crucial roles in MS pathogenesis, and the JAK2/STAT3 pathway has an essential function in their differentiation from naive CD4 + T cells. This study investigated the effects of the JAK2/STAT3 pathway inhibitor AG490 on EAE in vivo and in vitro, as well as the underlying mechanisms. AG490 ameliorated EAE severity and attenuated its typical symptoms by downregulating proteins associated with the JAK2/STAT3 pathway. Furthermore, it decreased T-helper 17 cell differentiation from naive CD4 + T cells by inactivating STAT3. In addition, it conferred protective effects against EAE by restoring autophagy. These findings indicate the potential of AG490 as a candidate anti-MS therapeutic.

The role of miRNAs in T helper cell development, activation, fate decisions and tumor immunity

T helper (Th) cells are central members of adaptive immunity and comprise the last line of defense against pathogen infection and malignant cell invasion by secreting specific cytokines. These cytokines then attract or induce the activation and differentiation of other immune cells, including antibody-producing B cells and cytotoxic CD8+ T cells. Therefore, the bidirectional communication between Th cells and tumor cells and their positioning within the tumor microenvironment (TME), especially the tumor immune microenvironment (TIME), sculpt the tumor immune landscape, which affects disease initiation and progression. The type, number, and condition of Th cells in the TME and TIME strongly affect tumor immunity, which is precisely regulated by key effectors, such as granzymes, perforins, cytokines, and chemokines. Moreover, microRNAs (miRNAs) have emerged as important regulators of Th cells. In this review, we discuss the role of miRNAs in regulating Th cell mediated adaptive immunity, focusing on the development, activation, fate decisions, and tumor immunity.

Targeting Interleukin-17 as a Novel Treatment Option for Fibrotic Diseases

Fibrosis is the end result of persistent inflammatory responses induced by a variety of stimuli, including chronic infections, autoimmune reactions, and tissue injury. Fibrotic diseases affect all vital organs and are characterized by a high rate of morbidity and mortality in the developed world. Until recently, there were no approved antifibrotic therapies. In recent years, high levels of interleukin-17 (IL-17) have been associated with chronic inflammatory diseases with fibrotic complications that culminate in organ failure. In this review, we provide an update on the role of IL-17 in fibrotic diseases, with particular attention to the most recent lines of research in the therapeutic field represented by the epigenetic mechanisms that control IL-17 levels in fibrosis. A better knowledge of the IL-17 signaling pathway implications in fibrosis could design new strategies for therapeutic benefits.

Supramolecular assemblies with spatio-temporal sequential drug delivery capability treat spinal cord injury via neuroprotection and immunoregulation

Spinal cord injury (SCI) can result in irreversible motor and sensory deficits. However, up to data, clinical first-line drugs have ambiguous benefits and debilitating side effects, mainly due to the insufficient accumulation, poor physiological barrier penetration, and lack of spatio-temporal controlled release at lesion tissue. Herein, we proposed a supramolecular assemblies composed of hyperbranched polymer-formed core/shell structure through host-guest interactions. Such HPAA-BM@CD-HPG-C assemblies co-loaded with p38 inhibitor (SB203580) and insulin-like growth factor 1(IGF-1) are able to achieve time- and space-programmed sequential delivery benefiting from their cascaded responsiveness. The core-shell disassembly of HPAA-BM@CD-HPG-C occurs in acidic micro-environment around lesion, achieving preferentially the burst release of IGF-1 to protect survival neurons. Subsequently, the HPAA-BM cores containing SB203580 are endocytosed by the recruited macrophages and degraded by intracellular GSH, accelerating the release of SB203580 to promote the conversion from M1 to M2 macrophage. Hence, the successive synergy of neuroprotection and immunoregulation effects contribute to subsequent nerve repair and locomotor recovery as demonstrated in vitro and in vivo studies. Thus, our fabrication provides a strategy that multiple drugs co-delivery in a spatio-temporal selective manner adapting to the disease progression through self-cascaded disintegration, are expected to realize multidimensional precise treatment of SCI.

miR-485 regulates Th17 generation and pathogenesis in experimental autoimmune encephalomyelitis through targeting STAT3

Experimental autoimmune encephalomyelitis (EAE) is an induced autoimmune disease widely used as an animal model for multiple sclerosis, which is mainly characterized by demyelination, axonal loss, as well as neurodegeneration of central nervous system (CNS). T-helper (Th) 17 cell that generate interleukin-17 (IL-17) plays a key role in its pathogenesis. Their activity and differentiation are tightly regulated by some cytokines and transcription factors. Certain microRNAs (miRNAs) are involved in the pathogenesis of various autoimmune disorders, including EAE. Our research detected a novel miRNA that can regulate EAE. According to the results, during EAE, the expression of miR-485 notably lowered, and STAT3 was significantly increased. It was discovered that miR-485 knockdown in vivo upregulated Th17-associated cytokines and aggravated EAE, while the overexpressed miR-485 down-regulated Th17-associated cytokines and mitigated EAE. The up-regulation of miRNA-485 in vitro inhibited Th17-associated cytokines expression within EAE CD4+ T cells. Furthermore, as revealed by target prediction and dual-luciferase reporter assays, miR-485 directly targets STAT3, a gene that encodes a protein responsible for Th17 generation. Overall, miR-485 exert vital functions in Th17 generation and EAE pathogenesis.

The involvement of TH17 cells in the pathogenesis of IBD

The pathogenesis of inflammatory bowel disease (IBD) is still unclear. Immune dysfunction may play a key role in the pathogenesis of IBD, in which the role of CD4⁺ T helper (Th) cells is particularly important. Th17 cells are a major component of CD4⁺ T cells, and their differentiation is regulated by a variety of extracellular signals, transcription factors, RNA, and posttranslational modifications. Th17 cells specifically produce IL-17 and play an important role in the protection of mucous membranes and epithelial tissues against infection by extracellular microbes. However, when immune regulation is dysfunctional, Th17 cells abnormally proliferate and produce large amounts of proinflammatory cytokines that can recruit other inflammatory cells, which together induce abnormal immune responses and result in the development of many autoimmune diseases. In recent years, studies have confirmed that Th17 cells play an important role in the pathogenesis of IBD, which makes it a possible target for IBD therapy. This article reviews the recent progress of Th17 cells involved in the pathogenesis of IBD and its targeted therapy.

Breast cancer tumor microenvironment affects Treg/IL-17-producing Treg/Th17 cell axis: Molecular and therapeutic perspectives

The tumor microenvironment (TME) comprises a variety of immune cells, among which T cells exert a prominent axial role in tumor development or anti-tumor responses in patients with breast cancer (BC). High or low levels of anti-inflammatory cytokines, such as transforming growth factor β, in the absence or presence of proinflammatory cytokines, such as interleukin-6 (IL-6), delineate the fate of T cells toward either regulatory T (Treg) or T helper 17 (Th17) cells, respectively. The transitional state of RORγt⁺Foxp3⁺ Treg (IL-17-producing Treg) resides in the middle of this reciprocal polarization, which is known as Treg/IL-17-producing Treg/Th17 cell axis. TME secretome, including microRNAs, cytokines, and extracellular vesicles, can significantly affect this axis. Furthermore, immune checkpoint inhibitors may be used to reconstruct immune cells; however, some of these novel therapies may favor tumor development. Therefore, understanding secretory and cell-associated factors involved in their differentiation or polarization and functions may be targeted for BC management. This review discusses microRNAs, cytokines, and extracellular vesicles (as secretome), as well as transcription factors and immune checkpoints (as cell-associated factors), which influence the Treg/IL-17-producing Treg/Th17 cell axis in BC. Furthermore, approved or ongoing clinical trials related to the modulation of this axis in the TME of BC are described to broaden new horizons of promising therapeutic approaches.

miRNA effects on gut homeostasis: therapeutic implications for inflammatory bowel disease

Inflammatory bowel disease (IBD) spans a range of chronic conditions affecting the gastrointestinal (GI) tract, which are marked by intermittent flare-ups and remissions. IBD results from microbial dysbiosis or a defective mucosal barrier in the gut that triggers an inappropriate immune response in a genetically susceptible person, altering the immune-microbiome axis. In this review, we discuss the regulatory roles of miRNAs, small noncoding RNAs with gene regulatory functions, in the stability and maintenance of the gut immune-microbiome axis, and detail the challenges and recent advances in the use of miRNAs as putative therapeutic agents for treating IBD.

Epigenetic Reprogramming of the Inflammatory Response in Obesity and Type 2 Diabetes

For the past several decades, the prevalence of obesity and type 2 diabetes (T2D) has continued to rise on a global level. The risk contributing to this pandemic implicates both genetic and environmental factors, which are functionally integrated by epigenetic mechanisms. While these conditions are accompanied by major abnormalities in fuel metabolism, evidence indicates that altered immune cell functions also play an important role in shaping of obesity and T2D phenotypes. Interestingly, these events have been shown to be determined by epigenetic mechanisms. Consistently, recent epigenome-wide association studies have demonstrated that immune cells from obese and T2D individuals feature specific epigenetic profiles when compared to those from healthy subjects. In this work, we have reviewed recent literature reporting epigenetic changes affecting the immune cell phenotype and function in obesity and T2D. We will further discuss therapeutic strategies targeting epigenetic marks for treating obesity and T2D-associated inflammation.

Extracellular Vesicles From Kidney Allografts Express miR-218-5p and Alter Th17/Treg Ratios

Delayed graft function (DGF) in kidney transplantation is associated with ischemic injury and carries long term functional and immunological risks. Extracellular vesicles (EV) released from allografts may signal a degree of ischemic stress, and are thought to play an important role in the development of anti-donor immunity. Here, we show that kidney perfusate-derived extracellular vesicles (KP-EV) express donor-specific human leukocyte antigen. KP-EV from kidneys that experience DGF increase the T-helper 17 (Th17) to T-regulatory (Treg) ratio in third party peripheral blood mononuclear cells to a greater degree than those from kidneys with immediate function. We report miR-218-5p upregulation in KP-EV of kidney transplant recipients with DGF. Levels of miR-218-5p in KP-EV inversely correlated with recipient eGFR at multiple time points following transplantation. Additionally, the degree of increase in Th17/Treg ratio by KP-EV positively correlated with miR-218-5p expression in KP-EV samples. Taken together, these data provide evidence that KP-EV may contribute to modulating immune responses in transplant recipients. This could lead to novel intervention strategies to inhibit DGF in order to improve graft function and survival.

IFN-γ-Primed hUCMSCs Significantly Reduced Inflammation via the Foxp3/ROR-γt/STAT3 Signaling Pathway in an Animal Model of Multiple Sclerosis

Our previous study showed that interferon gamma (IFN-γ) might enhance the immunosuppressive properties of mesenchymal stem cells (MSCs) by upregulating the expression of indoleamine 2,3-dioxygenease. Therefore, we treated experimental autoimmune encephalomyelitis (EAE) mice, an animal model of multiple sclerosis (MS), with IFN-γ-primed human umbilical cord MSCs (IFN-γ-hUCMSCs). This study aimed to investigate the potential therapeutic effects of IFN-γ-hUCMSCs transplantation and to identify the biological pathways involved in EAE mice. Firstly, the body weights and clinical scores of EAE mice were recorded before and after treatment. Then, the inflammatory cytokine levels in splenic cell supernatants were quantified by enzyme-linked immunosorbent assay. Finally, the mRNA expression levels of signal transducer and activator of transduction 3 (STAT3), retinoic acid-related orphan receptor gamma t (ROR-γt), and forkhead box P3 (Foxp3) were detected by quantitative reverse transcription polymerase chain reaction. We observed that IFN-γ-hUCMSCs transplantation significantly alleviated body weight loss and decreased the clinical scores of mice. Additionally, IFN-γ-hUCMSCs transplantation could regulate the production of inflammatory cytokines, interleukin (IL)-10 and IL-17, thereby showing more potent treatment efficacy than human umbilical cord MSCs (hUCMSCs) transplantation (p < 0.05). Compared with the EAE group, the expressions of STAT3 and ROR-γt in the transplantation groups were significantly decreased, but the expression of Foxp3 was significantly upregulated in the IFN-γ-hUCMSCs transplantation group compared to that in the hUCMSCs transplantation group. We assumed that IFN-γ-hUCMSCs may affect the balance of T helper 17 (Th17) cells/regulatory T cells (Tregs) through the Foxp3/ROR-γt/STAT3 signaling pathway to reduce the inflammatory response, thereby improving the clinical symptoms of EAE mice. Our study demonstrated that transplantation of IFN-γ-hUCMSCs could reduce inflammation in EAE mice via the Foxp3/ROR-γt/STAT3 signaling pathway, highlighting the therapeutic effects of IFN-γ-hUCMSCs in patients with MS.

MicroRNAs as T Lymphocyte Regulators in Multiple Sclerosis

MicroRNA (miRNA) is a class of endogenous non-coding small RNA with regulatory activities, which generally regulates the expression of target genes at the post-transcriptional level. Multiple Sclerosis (MS) is thought to be an autoimmune-mediated chronic inflammatory demyelinating disease of the central nervous system (CNS) that typically affect young adults. T lymphocytes play an important role in the pathogenesis of MS, and studies have suggested that miRNAs are involved in regulating the proliferation, differentiation, and functional maintenance of T lymphocytes in MS. Dysregulated expression of miRNAs may lead to the differentiation balance and dysfunction of T lymphocytes, and they are thus involved in the occurrence and development of MS. In addition, some specific miRNAs, such as miR-155 and miR-326, may have potential diagnostic values for MS or be useful for discriminating subtypes of MS. Moreover, miRNAs may be a promising therapeutic strategy for MS by regulating T lymphocyte function. By summarizing the recent literature, we reviewed the involvement of T lymphocytes in the pathogenesis of MS, the role of miRNAs in the pathogenesis and disease progression of MS by regulating T lymphocytes, the possibility of differentially expressed miRNAs to function as biomarkers for MS diagnosis, and the therapeutic potential of miRNAs in MS by regulating T lymphocytes.

Kidney microRNA Expression Pattern in Type 2 Diabetic Nephropathy in BTBR Ob/Ob Mice

Diabetic nephropathy (DN) is the main leading cause of chronic kidney disease worldwide. Although remarkable therapeutic advances have been made during the last few years, there still exists a high residual risk of disease progression to end-stage renal failure. To further understand the pathogenesis of tissue injury in this disease, by means of the Next-Generation Sequencing, we have studied the microRNA (miRNA) differential expression pattern in kidneys of Black and Tan Brachyury (BTBR) ob/ob (leptin deficiency mutation) mouse. This experimental model of type 2 diabetes and obesity recapitulates the key histopathological features described in advanced human DN and therefore can provide potential useful translational information. The miRNA-seq analysis, performed in the renal cortex of 22-week-old BTBR ob/ob mice, pointed out a set of 99 miRNAs significantly increased compared to non-diabetic, non-obese control mice of the same age, whereas no miRNAs were significantly decreased. Among them, miR-802, miR-34a, miR-132, miR-101a, and mir-379 were the most upregulated ones in diabetic kidneys. The in silico prediction of potential targets for the 99 miRNAs highlighted inflammatory and immune processes, as the most relevant pathways, emphasizing the importance of inflammation in the pathogenesis of kidney damage associated to diabetes. Other identified top canonical pathways were adipogenesis (related with ectopic fatty accumulation), necroptosis (an inflammatory and regulated form of cell death), and epithelial-to-mesenchymal transition, the latter supporting the importance of tubular cell phenotype changes in the pathogenesis of DN. These findings could facilitate a better understanding of this complex disease and potentially open new avenues for the design of novel therapeutic approaches to DN.

Human microRNA (miR-20b-5p) modulates Alzheimer's disease pathways and neuronal function, and a specific polymorphism close to the MIR20B gene influences Alzheimer's biomarkers

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with loss of cognitive, executive, and other mental functions, and is the most common form of age-related dementia. Amyloid-β peptide (Aβ) contributes to the etiology and progression of the disease. Aβ is derived from the amyloid-β precursor protein (APP). Multiple microRNA (miRNA) species are also implicated in AD. We report that human hsa-miR20b-5p (miR-20b), produced from the MIR20B gene on Chromosome X, may play complex roles in AD pathogenesis, including Aβ regulation. Specifically, miR-20b-5p miRNA levels were altered in association with disease progression in three regions of the human brain: temporal neocortex, cerebellum, and posterior cingulate cortex. In cultured human neuronal cells, miR-20b-5p treatment interfered with calcium homeostasis, neurite outgrowth, and branchpoints. A single-nucleotide polymorphism (SNP) upstream of the MIR20B gene (rs13897515) associated with differences in levels of cerebrospinal fluid (CSF) Aβ1-42 and thickness of the entorhinal cortex. We located a miR-20b-5p binding site in the APP mRNA 3'-untranslated region (UTR), and treatment with miR-20b-5p reduced APP mRNA and protein levels. Network analysis of protein-protein interactions and gene coexpression revealed other important potential miR-20b-5p targets among AD-related proteins/genes. MiR-20b-5p, a miRNA that downregulated APP, was paradoxically associated with an increased risk for AD. However, miR-20b-5p also reduced, and the blockade of APP by siRNA likewise reduced calcium influx. As APP plays vital roles in neuronal health and does not exist solely to be the source of "pathogenic" Aβ, the molecular etiology of AD is likely to not just be a disease of "excess" but a disruption of delicate homeostasis.

The MicroRNA-106a/20b Strongly Enhances the Antitumour Immune Responses of Dendritic Cells Pulsed with Glioma Stem Cells by Targeting STAT3

BACKGROUND

Evaluate the effect of the miRNA-106a/20b on the efficacy of DCs pulsed with GSCs in activating GSC-specific T cell responses.

METHODS

We cultured GSCs and prepared GSC antigen lysates by apoptosis. Then, immature DCs were pulsed with GSC antigen lysates in vitro. STAT3 levels in DCs were assessed by Western blotting, and the expression of CD80, CD86, and MHC-II was tested by fluorescence-activated cell sorting. The production and secretion of the cytokines IL-6, IL-12, TNF-α, and IL-10 in DCs induced by GSCs were determined by enzyme-linked immunosorbent assay. Finally, the cytotoxic functions of T cells stimulated by GSC-DC fusion cells transfected with a miR-106a/20b mimic in vitro and the antitumour activity in vivo were detected.

RESULTS

We found that the levels of miR-106a/20b were downregulated, but the expression of STAT3 was significantly upregulated. Simultaneously, the inhibition of STAT3 in the fusion cells by STAT3-specific siRNA caused significant upregulation of the expression of CD80, CD86, and MHC-II, and the secretion of the cytokines IL-6 and IL-12 was substantially increased, IL-10 was markedly decreased. These findings revealed that STAT3 is an important regulator of DC maturation. Furthermore, the interactional binding sites between the 3'-untranslated region (3'-UTR) of STAT3 mRNA and miR-106a/20b were predicted by bioinformatics and verified by a dual-luciferase assay. Moreover, the reduction in STAT3 levels in GSC-DCs enhanced the generation of CD8+ T cells and reduced the generation of Foxp3+ regulatory T cells. Meanwhile, the secretion of the T cell cytokine IFN-γ was significantly increased. Further research showed that DCs after miR-106a/20b-mimics transfection could promote the inhibition of GSC proliferation by T cells in vitro and suppress tumour growth in vivo.

CONCLUSIONS

This study indicted that the miR-106a/20b activation could be one of the important molecular mechanisms leading to enhance antitumour immune responses of GSC-mediated DCs, which downregulated the expression of STAT3 to alleviate its the inhibitory effect.

Scavenging the hidden impacts of non-coding RNAs in multiple sclerosis

Multiple sclerosis (MS) is a chronic neuroinflammatory disease that causes severe neurological dysfunction leading to disabilities in patients. The prevalence of the disease has been increasing gradually worldwide, and the specific etiology behind the disease is not yet fully understood. Therapies aimed against treating MS patients have been growing lately, intending to delay the disease progression and increase the patients' quality of life. Various pathways play crucial roles in developing the disease, and several therapeutic approaches have been tackling those pathways. However, these strategies have shown several side effects and inconsistent efficacy. MicroRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) have been shown to act as key players in various disease pathogenesis and development. Several proinflammatory and anti-inflammatory miRNAs have been reported to participate in the development of MS. Hence, the review assesses the role of miRNAs, lncRNAs, and circRNAs in regulating immune cell functions better to understand their impact on the molecular mechanics of MS.

Cytokine storm in the pathophysiology of COVID-19: Possible functional disturbances of miRNAs

SARS-CoV-2, as the causative agent of COVID-19, is an enveloped positives-sense single-stranded RNA virus that belongs to the Beta-CoVs sub-family. A sophisticated hyper-inflammatory reaction named cytokine storm is occurred in patients with severe/critical COVID-19, following an imbalance in immune-inflammatory processes and inhibition of antiviral responses by SARS-CoV-2, which leads to pulmonary failure, ARDS, and death. The miRNAs are small non-coding RNAs with an average length of 22 nucleotides which play various roles as one of the main modulators of genes expression and maintenance of immune system homeostasis. Recent evidence has shown that Homo sapiens (hsa)-miRNAs have the potential to work in three pivotal areas including targeting the virus genome, regulating the inflammatory signaling pathways, and reinforcing the production/signaling of IFNs-I. However, it seems that several SARS-CoV-2-induced interfering agents such as viral (v)-miRNAs, cytokine content, competing endogenous RNAs (ceRNAs), etc. preclude efficient function of hsa-miRNAs in severe/critical COVID-19. This subsequently leads to increased virus replication, intense inflammatory processes, and secondary complications development. In this review article, we provide an overview of hsa-miRNAs roles in viral genome targeting, inflammatory pathways modulation, and IFNs responses amplification in severe/critical COVID-19 accompanied by probable interventional factors and their function. Identification and monitoring of these interventional elements can help us in designing the miRNAs-based therapy for the reduction of complications/mortality rate in patients with severe/critical forms of the disease.

ZIKV Infection and miRNA Network in Pathogenesis and Immune Response

Over the years, viral infections have caused severe illness in humans. Zika Virus (ZIKV) is a flavivirus transmitted by mosquito vectors that leads to notable neurological impairment, whose most dramatic impact is the Congenital ZIKV Syndrome (CZS). ZIKV targets neuronal precursor cells leading to apoptosis and further impairment of neuronal development, causing microcephaly, lissencephaly, ventriculomegaly, and calcifications. Several regulators of biological processes are involved in CZS development, and in this context, microRNAs (miRNAs) seem to have a fundamental role. miRNAs are important regulators of protein translation, as they form the RISC silencing complex and interact with complementary mRNA target sequences to further post-transcriptional repression. In this context, little is known about their participation in the pathogenesis of viral infections. In this review, we discuss how miRNAs could relate to ZIKV and other flavivirus infections.

The circular RNA circINPP4B acts as a sponge of miR-30a to regulate Th17 cell differentiation during progression of experimental autoimmune encephalomyelitis

Circular RNAs (circRNAs) regulate gene expression and participate in various biological and pathological processes. However, little is known about the effects of specific circRNAs on T helper cell 17 (Th17) differentiation and related autoimmune diseases, such as multiple sclerosis (MS). Here, using transcriptome microarray analysis at different stages of experimental autoimmune encephalomyelitis (EAE), we identified the EAE progression-related circINPP4B, which showed upregulated expression in Th17 cells from mice with EAE and during Th17 differentiation in vitro. Silencing of circINPP4B inhibited Th17 differentiation and alleviated EAE, characterized by less demyelination and Th17 infiltration in the spinal cord. Mechanistically, circINPP4B served as a sponge that directly targeted miR-30a to regulate Th17 differentiation. Furthermore, circINPP4B levels were associated with the developing phases of clinical relapsing-remitting MS patients. Our results indicate that circINPP4B plays an important role in promoting Th17 differentiation and progression of EAE by targeting miR-30a, which provides a potential diagnostic and therapeutic target for Th17-mediated MS.

Epigallocatechin-3 gallate regulates macrophage subtypes and immunometabolism to ameliorate experimental autoimmune encephalomyelitis

Epigallocatechin-3 gallate (EGCG) is a polyphenolic component of tea and has potential curative effects in patients with autoimmune diseases. Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS). It remains unknown whether EGCG can regulate macrophage subtypes in MS. Here we evaluated the effects of EGCG in experimental autoimmune encephalomyelitis (EAE), MS mouse model. We found that EGCG treatment reduced EAE severity and macrophage inflammation in the CNS. Moreover, EAE severity was well correlated with the ratio of M1 to M2 macrophages, and EGCG treatment suppressed M1 macrophage-mediated inflammation in spleen. In vitro experiments showed that EGCG inhibited M1 macrophage polarization, but promoted M2 macrophage polarization. These effects were likely to be related to the inhibition of nuclear factor-κB signaling and glycolysis in macrophages by EGCG in macrophages. Overall, these findings provided important insights into the mechanisms through which EGCG may mediate MS.

Association of microRNA expression with changes in immune markers in workers with cadmium exposure

Human exposure to cadmium (Cd) is known to produce severe health effects. Recently, molecular mechanism of Cd toxicity has revealed the role of Cd in causing epigenetic alterations. miRNAs are small, non-coding RNAs which are involved in translational repression of genes. Therefore, the aim of the present study was to evaluate the alterations in expression of miRNAs associated with inflammation, carcinogenesis and, further, study their possible correlation with immune profile, in occupationally Cd exposed workers of Jodhpur. 106 workers from metal handicraft and welding factories were recruited as subjects, while, 80 apparently healthy non-exposed individuals served as control for this study. Blood Cd levels (BCd) were determined by Graphite Furnace Atomic Absorption Spectroscopy (GFAAS). Lymphocyte cell subset were measured by flow cytometry, serum interleukins were assessed by ELISA and miRNA expression was determined by Real Time Polymerase Chain Reaction (RT-PCR). BCd levels were significantly higher in the exposed individuals when compared to the non-exposed, with welders reporting the highest amongst all. Among the lymphocyte subset, exposed group showed significantly higher percentage of Th17 and lower percentage of Treg population. Cytokine profile expressed by exposed workers were predominantly pro-inflammatory in nature. Among, the studied miRNAs, miR-221 was significantly higher in exposed group with a fold change of 3.05. Additionally, miR-221 and miR-155 showed significant positive correlation with Th17 cell %. Regression analysis showed duration of exposure and IL-17 to have significant effect on miR-221 in exposed group. In conclusion, miR-221 was significantly upregulated in exposed and was correlated with immune alteration making it a potential candidate for further exploration of mechanism underlying Cd toxicity.

Upregulation of the miRNA-155, miRNA-210, and miRNA-20b in psoriasis patients and their relation to IL-17

Psoriasis is an immune-mediated disease, with genetic background and triggering environmental factors; however, several gaps are still present in understanding the intertwined relationship between these elements. Epigenetic mechanisms, including microRNAs (miRNAs), play an important role in the pathogenesis of psoriasis. The relationship between interleukin (IL)-17, a key cytokine in psoriasis, and these epigenetic mechanisms still needs to be elucidated. This study aimed at assessing the expression of miRNA-155, miRNA-210, and miRNA-20b in skin and sera of psoriasis patients in relation to IL-17 levels. For 20 psoriasis patients and 20 matching controls, the expression of miRNA-155, miRNA-210, and miRNA-20b was assessed using real-time polymerase chain reaction (RT-PCR), whereas IL-17/IL-17A levels were measured using quantitative enzyme-linked immunosorbent assay (ELISA) technique. MiRNA-155 expression was significantly higher in lesional skin compared to controls (P = 0.001). MiRNA-210 expression was significantly higher in both, lesional skin (P = 0.010) and sera of patients (P = 0.001) in comparison with controls. A statistically significant positive correlation was found between serum miRNA-210 expression and serum levels of IL-17/IL-17A (P = 0.010, rs = 0.562). MiRNA-20b lesional and non-lesional expression was significantly higher than controls (P < 0.001; P = 0.018). In conclusion, the expression of miRNA-155, miRNA-210, and miRNA-20b is exaggerated in psoriasis and they may be involved in disease pathogenesis. A possible relationship between miRNA-210 and IL-17 may be suggested; however, further studies are still needed to verify this relation.

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.

The emerging role of miRNA in the perturbation of tumor immune microenvironment in chemoresistance: Therapeutic implications

Chemoresistance is a major hindrance in cancer chemotherapies, a leading cause of tumor recurrence and cancer-related deaths. Cancer cells develop numerous strategies to elude immune attacks and are regulated by immunological factors. Cancer cells can alter the expression of several immune modulators to upregulate the activities of immune checkpoint pathways. Targeting the immune checkpoint inhibitors is a part of the cancer immunotherapy altered during carcinogenesis. These immune modulators have the capability to reprogram the tumor microenvironment, thereby change the efficacy of chemotherapeutics. In general, the sensitivity of drugs is reduced in the immunosuppressive tumor microenvironment, resulting in chemoresistance and tumor relapse. The regulation of microRNAs (miRNAs) is well established in cancer initiation, progression, and therapy. Intriguingly, miRNA affects cancer immune surveillance and immune response by targeting immune checkpoint inhibitors in the tumor microenvironment. miRNAs alter the gene expression at the post-transcriptional level, which modulates both innate and adaptive immune systems. Alteration of tumor immune microenvironment influences drug sensitivity towards cancer cells. Besides, the expression profile of immune-modulatory miRNAs can be used as a potential biomarker to predict the response and clinical outcomes in cancer immunotherapy and chemotherapy. Recent evidences have revealed that cancer-derived immune-modulatory miRNAs might be promising targets to counteract cancer immune escape, thereby increasing drug efficacy. In this review, we have compiled the role of miRNAs in overcoming the chemoresistance by modulating tumor microenvironment and discussed their preclinical and clinical implications.

miRNA-467b inhibits Th17 differentiation by targeting eIF4E in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) are neuroinflammatory autoimmune diseases characterized by the axonal loss, demyelination, and neurodegeneration of the central nervous system. Overactivation of CD4⁺ T cells, especially the migration of the Th1 and Th17 subsets into the central nervous system (CNS), leads to the secretion of inflammatory mediators and destruction of the contact between neurons and activated macrophages, which can then result in a series of neurocognitive and motor deficits. In this study, we intended to explore the role of miRNA-467b in regulating Th cell development in EAE. We found that the level of miRNA-467b was decreased and eukaryotic initiation factor 4 F (eIF4E) was increased in lymph nodes and the CNS at EAE peak. eIF4E was confirmed as the direct target of miRNA467b. Overexpression of miRNA-467b could suppress a percentage of CD4⁺ IL-17⁺ cells in EAE CD4 + T cells in vitro. In addition, we also identified miRNA-467b, which could suppress Th17 cell differentiation by targeting eIF4E in vitro. Furthermore, injecting miRNA-467b mimics into the caudal vein of EAE mice contributed to less inflammation in the peripheral lymphoid organs and CNS and alleviated disease severity. Taken together, our findings imply that miRNA-467b inhibits the differentiation and function of Th17 cells by targeting eIF4E, thereby alleviating EAE.

miRNA-Dependent CD4+ T Cell Differentiation in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is characterized by multifocal lesions, chronic inflammatory condition, and degenerative processes within the central nervous system (CNS) leading to demyelination. The most important cells involved in its pathogenesis are those which are CD4⁺, particularly proinflammatory Th1/Th17 and regulatory Treg. Signal cascades associated with CD4⁺ differentiation are regulated by microRNAs (miRNAs): short, single-stranded RNAs, responsible for negative regulation of gene expression at the posttranscriptional level. Several miRNAs have been consistently reported as showing dysregulated expression in MS, and their expression patterns may be elevated or decreased, depending on the function of specific miRNA in the immune system. Studies in MS patients indicate that, among others, miR-141, miR-200a, miR-155, miR-223, and miR-326 are upregulated, while miR-15b, miR-20b, miR-26a, and miR-30a are downregulated. Dysregulation of these miRNAs may contribute to the imbalance between pro- and anti-inflammatory processes, since their targets are associated with the regulation of Th1/Th17 and Treg cell differentiation. Highly expressed miRNAs can in turn suppress translation of key Th1/Th17 differentiation inhibitors. miRNA dysregulation may result from the impact of various factors at each stage of their biogenesis. Immature miRNA undergoes multistage transcriptional and posttranscriptional modifications; therefore, any protein involved in the processing of miRNAs can potentially lead to disturbances in their expression. Epigenetic modifications that have a direct impact on miRNA gene transcription may also play an important role.

Inflammatory Cytokines in Diabetic Kidney Disease: Pathophysiologic and Therapeutic Implications

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease and a main contributing factor for cardiovascular morbidity and mortality in patients with diabetes mellitus. Strategies employed to delay the progression of this pathology focus on the control of traditional risk factors, such as hyperglycemia, and elevated blood pressure. Although the intimate mechanisms involved in the onset and progression of DKD remain incompletely understood, inflammation is currently recognized as one of the main underlying processes. Untangling the mechanisms involved in the appearing of a harmful inflammatory response in the diabetic patient is crucial for the development of new therapeutic strategies. In this review, we focus on the inflammation-related pathogenic mechanisms involved in DKD and in the therapeutic utility of new anti-inflammatory strategies.

Let-7f-5p suppresses Th17 differentiation via targeting STAT3 in multiple sclerosis

T helper 17 (Th17) cells are regarded as key factors in the pathogenesis of multiple sclerosis (MS). Although the involvement of certain microRNAs (miRNAs) in the development of MS has been reported, their roles in Th17 cell differentiation and MS pathogenesis remain elusive. In this study, we identified that let-7f-5p expression is significantly downregulated in CD4⁺ T cells from MS patients and during the process of Th17 differentiation. The overexpression of let-7f-5p suppressed Th17 differentiation, whereas the knockdown of let-7f-5p expression enhanced this progress. We then explored the molecular mechanism through which let-7f-5p suppressed Th17 differentiation and identified signal transducer and activator of transcription 3 (STAT3), a pivotal transcription factor of Th17 cells, as a direct target of let-7f-5p. In contrast to the downregulated expression of let-7f-5p, STAT3 and p-STAT3 protein levels were dramatically upregulated and inversely correlated with let-7f-5p in peripheral blood CD4⁺ T cells from MS patients. In conclusion, let-7f-5p functions as a potential inhibitor of Th17 differentiation in the pathogenesis of MS by targeting STAT3 and may serve as a new therapeutic target.

Epigenetics in Multiple Sclerosis

Multiple sclerosis (MS) is an aggravating autoimmune disease that cripples young patients slowly with physical, sensory and cognitive deficits. The break of self-tolerance to neuronal antigens is the key to the pathogenesis of MS, with autoreactive T cells causing demyelination that subsequently leads to inflammation-mediated neurodegenerative events in the central nervous system. The exact etiology of MS remains elusive; however, the interplay of genetic and environmental factors contributes to disease development and progression. Given that genetic variation only accounts for a fraction of risk for MS, extrinsic risk factors including smoking, infection and lack of vitamin D or sunshine, which cause changes in gene expression, contribute to disease development through epigenetic regulation. To date, there is a growing body of scientific evidence to support the important roles of epigenetic processes in MS. In this chapter, the three main layers of epigenetic regulatory mechanisms, namely DNA methylation, histone modification and microRNA-mediated gene regulation, will be discussed, with a particular focus on the role of epigenetics on dysregulated immune responses and neurodegenerative events in MS. Also, the potential for epigenetic modifiers as biomarkers and therapeutics for MS will be reviewed.

microRNAs: key modulators of disease-modifying therapies in multiple sclerosis

There is a high level of heterogeneity in symptom manifestations and response to disease-modifying therapies (DMTs) in multiple sclerosis (MS), an immune-based neurodegenerative disease with ever-increasing prevalence in recent decades. Because of unknown aspects of the etiopathology of MS and mechanism of action of DMTs, the reason for this variability is undetermined, and much remains to be understood. Traditionally, physicians consider switching to other DMTs based on the exacerbation of symptoms and/or change in the results of magnetic resonance imaging and biochemical factors. Therefore, identifying biological treatment response markers that help us recognizing non-responders rapidly and subsequently choosing another DMTs is necessary. microRNAs (miRNAs) are micromanagers of gene expression which have been profiled in different samples of MS patients, highlighting their role in pathogenetic of MS. Recent studies have investigated expression profiling of miRNAs after treatment with DMTs to clarify possible DMTs-mediated mechanism and obtaining response to therapy biomarkers. In this review, we will discuss the modulation of miRNAs by DMTs in cells and pathways involved in MS.

miR-145 Inhibits Th9 Cell Differentiation by Suppressing Activation of the PI3K/Akt/mTOR/p70S6K/HIF-1α Pathway in Malignant Ascites from Liver Cancer

Purpose

Our previous experiments confirmed that T helper type 9 (Th9) cells were involved in the occurrence and development of malignant ascites caused by liver cancer. The current study investigated the mechanism underlying microRNA (miR-145)-mediated inhibition of Th9 cells in an malignant ascites model with liver cancer.

Materials and Methods

CD4+ T cells were induced to differentiate Th9 cells after transfection with miR-145 mimics or negative control. A malignant ascites mouse model was transfected with miR-145agomir or negative control. Th9 cells were detected by flow cytometry. Enzyme-linked immunosorbent assay was applied to detect the interleukin 9 (IL-9) cytokine and hypoxia-inducible factor 1 alpha (HIF-1α). RT-PCR was used to detect the expression of miR-145 and phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin/p70 ribosomal protein S6 kinase/HIF-1α (PI3K/Akt/mTOR/p70S6K/HIF-1α) mRNA. Western blotting and immunofluorescence were performed to detect the expression of PI3K/Akt/mTOR/p70S6K/HIF-1α-related proteins.

Results

In vitro experiments showed that miR-145 inhibited Th9 cell polarization, HIF-1α expression, and PI3K/Akt/mTOR/p70S6K pathway activation. In the malignant ascites mouse model, miR-145 also demonstrated inhibitory effects on Th9 cell differentiation through the PI3K/Akt/mTOR/p70S6K/HIF-1α pathway.

Conclusion

miR-145 may inhibit Th9 cell differentiation through the PI3K/Akt/mTOR/p70S6K/HIF-1α pathway. These findings suggest a novel therapeutic target for malignant ascites from liver cancer.

Long non-coding RNA MALAT1 aggravates human retinoblastoma by sponging miR-20b-5p to upregulate STAT3

OBJECTIVE

Retinoblastoma (RB) is an uncommon childhood carcinoma of the developing retina. Long non-coding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (MALAT1), microRNA-20b-5p (miR-20b-5p) and signal transducer and activator of transcription 3 (STAT3) was revealed to partake in RB. But their relationship was still to be investigated, so we intended to discuss the specific interaction of MALAT1, miR-20b-5p and STAT3 in RB.

METHODS

By RNA isolation and quantitation, we measured the MALAT1 expression in RB tissues and cell lines. Then, to determine the influence of MALAT1 on RB cells, RB cells were transfected with siRNA-MALAT1 or pcDNA-MALAT1. The interplay among MALAT1, miR-20b-5p and STAT3 were evaluated through dual luciferase reporter gene assay and RNA pull-down after RB cells treated with siRNA/pcDNA-MALAT1 or/and miR-20b-5p mimic/inhibitor. The influence of their interaction on cells was evaluated by cell counting kit-8, EdU assay and flow cytometry. Finally, the involvement of MALAT1 in tumorigenesis was elucidated in vivo.

RESULTS

Both RB tissues and cells showed highly expressed MALAT1. When MALAT1 was downregulated, RB cell proliferation was hindered and apoptosis was accelerated. MALAT1 sponged miR-20b-5p and upregulated STAT3. Silencing MALAT1 or overexpressing miR-20b-5p inhibited proliferation and promoted apoptosis in RB cells. The tumor growth of nude mice treated with siRNA-MALAT1 was inhibited.

CONCLUSION

MALAT1 could increase proliferation and reduce apoptosis by sponging miR-20b-5p to upregulate STAT3 in RB cells. Therefore, MALAT1 might be a latent target in the RB treatment.

The impact of microRNAs on alterations of gene regulatory networks in allergic diseases

Allergic diseases including asthma are worldwide on the rise and contribute significantly to health expenditures. Allergic diseases are prototypic diseases with a strong gene by environment interaction component and epigenetic mechanisms might mediate the effects of the environment on the disease phenotype. MicroRNAs, small non-coding RNAs (miRNAs), regulate gene expression post-transcriptionally. Functional single-stranded miRNAs are generated in multiple steps of enzymatic processing from their precursors and mature miRNAs are included into the RNA-induced silencing complex (RISC). They imperfectly base-pair with the 3'UTR region of targeted genes leading to translational repression or mRNA decay. The cellular context and microenvironment as well the isoform of the mRNA control the dynamics and complexity of the regulatory circuits induced by miRNAs that regulate cell fate decisions and function. MiR-21, miR-146a/b and miR-155 are among the best understood miRNAs of the immune system and implicated in different diseases including allergic diseases. MiRNAs are implicated in the induction of the allergy reinforcing the Th2 phenotype (miR-19a, miR-24, miR-27), while other miRNAs promote regulatory T cells associated with allergen tolerance or unresponsiveness. In the current chapter we describe in detail the biogenesis and regulatory function of miRNAs and summarize current knowledge on miRNAs in allergic diseases and allergy relevant cell fate decisions focusing mainly on immune cells. Furthermore, we evoke the principles of regulatory loops and feedback mechanisms involving miRNAs on examples with relevance for allergic diseases. Finally, we show the potential of miRNAs and exosomes containing miRNAs present in several biological fluids that can be exploited with non-invasive procedures for diagnostic and potentially therapeutic purposes.

Roles of mTORC1 and mTORC2 in controlling γδ T1 and γδ T17 differentiation and function

The metabolism-controlled differentiation of αβ T cells has been well documented; however, the role of a metabolism program in γδ T cell differentiation and function has not been clarified. Here, using CD2-cre; mTORC1 Raptor-f/f, and mTORC2 Rictor-f/f mice (KO mice), we found that mTORC1, but not mTORC2, was required for the proliferation and survival of peripheral γδ T cells, especially Vγ4 γδ T cells. Moreover, mTORC1 was essential for both γδ T1 and γδ Τ17 differentiation, whereas mTORC2 was required for γδ T17, but not for γδ Τ1, differentiation. We further studied the underlying molecular mechanisms and found that depletion of mTORC1 resulted in the increased expression of SOCS1, which in turn suppressed the key transcription factor Eomes, consequentially reducing IFN-γ production. Whereas the reduced glycolysis resulted in impaired γδ Τ17 differentiation in Raptor KO γδ T cells. In contrast, mTORC2 potentiated γδ Τ17 induction by suppressing mitochondrial ROS (mitoROS) production. Consistent with their cytokine production profiles, the Raptor KO γδ T cells lost their anti-tumor function both in vitro and in vivo, whereas both Raptor and Rictor KO mice were resistant to imiquimod (IMQ)-induced psoriasis-like skin pathogenesis. In summary, we identified previously unknown functions of mTORC1 and mTORC2 in γδ T cell differentiation and clarified their divergent roles in mediating the activity of γδ T cells in tumors and autoimmunity.

LncRNA GAS5 inhibits Th17 differentiation and alleviates immune thrombocytopenia via promoting the ubiquitination of STAT3

BACKGROUND

The increased differentiation of T helper 17 cells (Th17) accelerates the development of immune thrombocytopenia (ITP), which is a common autoimmune disease with limited therapeutic methods. Recent studies have revealed that long non-coding RNAs (lncRNAs) play a critical role in autoimmune diseases, thus this study aims to investigate the effect of lncRNA GAS5 on the differentiation of Th17 cells in ITP.

METHODS

The expression of GAS5 in peripheral blood mononuclear cells (PBMCs) of ITP patients and spleen tissues of ITP mice was measured by qRT-PCR. The percentage of Th17 cells in CD4⁺ cells was measured by flow cytometry. The combination between GAS5 and STAT3 was confirmed by RNA pull-down assay and RNA Binding Protein Immunoprecipitation (RIP). The ubiquitination of STAT3 was detected by ubiquitination assay and the interaction between STAT3 and TRAF6 was measured by Co-Immunoprecipitation (Co-IP). Finally, the effect of GAS5 on Th17 differentiation was investigated in vitro and in vivo using lentivirus (lenti)-GAS5.

RESULTS

GAS5 expression was downregulated both in PBMCs of ITP patients and spleen tissues of ITP mice. Overexpression of GAS5 suppressed Th17 differentiation while had no effect on Treg differentiation in naïve CD4⁺ cells. RNA pull-down and RNA immunoprecipitation assays confirmed the interaction between GAS5 and STAT3. Further studies showed GAS5 accelerated the degradation of STAT3 via promoting TRAF6-mediated ubiquitination. Overexpressing GAS5 suppressed Th17 differentiation in vitro and alleviated ITP in vivo via reducing STAT3.

CONCLUSION

LncRNA GAS5 inhibited Th17 differentiation through promoting the TRAF6-mediated ubiquitination of STAT3, thus relieving ITP.

Environmental Influencers, MicroRNA, and Multiple Sclerosis

Multiple sclerosis (MS) is a complex neurological disorder characterized by an aberrant immune system that affects patients' quality of life. Several environmental factors have previously been proposed to associate with MS pathophysiology, including vitamin D deficiency, Epstein-Barr virus (EBV) infection, and cigarette smoking. These factors may influence cellular molecularity, interfering with cellular proliferation, differentiation, and apoptosis. This review argues that small noncoding RNA named microRNA (miRNA) influences these factors' mode of action. Dysregulation in the miRNAs network may deeply impact cellular hemostasis, thereby possibly resulting in MS pathogenicity. This article represents a literature review and an author's theory of how environmental factors may induce dysregulations in the miRNAs network, which could ultimately affect MS pathogenicity.

Could IL-17A Be a Novel Therapeutic Target in Diabetic Nephropathy?

Chronic kidney disease has become a major medical issue in recent years due to its high prevalence worldwide, its association with premature mortality, and its social and economic implications. A number of patients gradually progress to end-stage renal disease (ESRD), requiring then dialysis and kidney transplantation. Currently, approximately 40% of patients with diabetes develop kidney disease, making it the most prevalent cause of ESRD. Thus, more effective therapies for diabetic nephropathy are needed. In preclinical studies of diabetes, anti-inflammatory therapeutic strategies have been used to protect the kidneys. Recent evidence supports that immune cells play an active role in the pathogenesis of diabetic nephropathy. Th17 immune cells and their effector cytokine IL-17A have recently emerged as promising targets in several clinical conditions, including renal diseases. Here, we review current knowledge regarding the involvement of Th17/IL-17A in the genesis of diabetic renal injury, as well as the rationale behind targeting IL-17A as an additional therapy in patients with diabetic nephropathy.

MicroRNAs as disease progression biomarkers and therapeutic targets in experimental autoimmune encephalomyelitis model of multiple sclerosis

Multiple sclerosis is an autoimmune neurodegenerative disease of the central nervous system characterized by pronounced inflammatory infiltrates entering the brain, spinal cord and optic nerve leading to demyelination. Focal demyelination is associated with relapsing-remitting multiple sclerosis, while progressive forms of the disease show axonal degeneration and neuronal loss. The tests currently used in the clinical diagnosis and management of multiple sclerosis have limitations due to specificity and sensitivity. MicroRNAs (miRNAs) are dysregulated in many diseases and disorders including demyelinating and neuroinflammatory diseases. A review of recent studies with the experimental autoimmune encephalomyelitis animal model (mostly female mice 6–12 weeks of age) has confirmed miRNAs as biomarkers of experimental autoimmune encephalomyelitis disease and importantly at the pre-onset (asymptomatic) stage when assessed in blood plasma and urine exosomes, and spinal cord tissue. The expression of certain miRNAs was also dysregulated at the onset and peak of disease in blood plasma and urine exosomes, brain and spinal cord tissue, and at the post-peak (chronic) stage of experimental autoimmune encephalomyelitis disease in spinal cord tissue. Therapies using miRNA mimics or inhibitors were found to delay the induction and alleviate the severity of experimental autoimmune encephalomyelitis disease. Interestingly, experimental autoimmune encephalomyelitis disease severity was reduced by overexpression of miR-146a, miR-23b, miR-497, miR-26a, and miR-20b, or by suppression of miR-182, miR-181c, miR-223, miR-155, and miR-873. Further studies are warranted on determining more fully miRNA profiles in blood plasma and urine exosomes of experimental autoimmune encephalomyelitis animals since they could serve as biomarkers of asymptomatic multiple sclerosis and disease course. Additionally, studies should be performed with male mice of a similar age, and with aged male and female mice.

Accelerated aging induced by deficiency of Zmpste24 protects old mice to develop bleomycin-induced pulmonary fibrosis

Idiopathic pulmonary fibrosis is a devastating aging-associated disease of unknown etiology. Despite that aging is a major risk factor, the mechanisms linking aging with this disease are uncertain, and experimental models to explore them in lung fibrosis are scanty. We examined the fibrotic response to bleomycin-induced lung injury in Zmpste24-deficient mice, which exhibit nuclear lamina defects developing accelerated aging. We found that young WT and Zmpste24(-/-) mice developed a similar fibrotic response to bleomycin. Unexpectedly, while old WT mice developed severe lung fibrosis, accelerated aged Zmpste24-/- mice were protected showing scant lung damage. To investigate possible mechanisms associated with this resistance to fibrosis, we compared the transcriptome signature of the lungs and found that Zmpste24(-/-) mice showed downregulation of several core and associated matrisome genes compared with WT mice. Interestingly, some microRNAs that target extracellular matrix molecules such as miR23a, miR27a, miR29a, miR29b-1, miR145a, and miR491 were dysregulated resulting in downregulation of profibrotic pathways such as TGF-β/SMAD3/NF-κB and Wnt3a/β-catenin signaling axis. These results indicate that the absence of Zmpste24 in aging mice results in impaired lung fibrotic response after injury, which is likely associated to the dysregulation of fibrosis-related miRNAs.

The inflammatory effect of epigenetic factors and modifications in type 2 diabetes

Inflammation has a central role in the etiology of type 2 diabetes (T2D) and its complications. Both genetic and epigenetic factors have been implicated in the development of T2D-associated inflammation. Epigenetic mechanisms regulate the function of several components of the immune system. Diabetic conditions trigger aberrant epigenetic alterations that contribute to the progression of insulin resistance and β-cell dysfunction by induction of inflammatory responses. Thus, targeting epigenetic factors and modifications, as one of the underlying causes of inflammation, could lead to the development of novel immune-based strategies for the treatment of T2D. The aim of this review is to provide an overview of the epigenetic mechanisms involved in the propagation and perpetuation of chronic inflammation in T2D. We also discuss the possible anti-inflammatory approaches that target epigenetic factors for the treatment of T2D.

RORγT is overexpressed in iNKT and γδ T cells during relapse in relapsing-remitting multiple sclerosis

The aim of the current study is to evaluate IL-17 production and RORγT, and IL-23R expression by iNKT, Th17 and γδ T cells in the peripheral blood of relapsing-remitting multiple sclerosis patients. Samples of peripheral blood from 21 relapse patients and 12 remission patients, and 15 healthy volunteers were stained with monoclonal antibodies for flow cytometry analysis. No significant differences in iNKT, γδ T and Th17 percentages were noted. The significant overexpression of RORγT was observed in all three subpopulations - therefore, iNKT, γδ T and Th cells may be an important source of IL-17 shortly prior to the relapse.

Small non-coding RNAs as important players, biomarkers and therapeutic targets in multiple sclerosis: A comprehensive overview

Multiple sclerosis (MS) is a leading cause of progressive disability among young adults caused by inflammation, demyelination and axonal loss in the central nervous system. Small non-coding RNAs (sncRNAs) are important regulators of various biological processes and could therefore play important roles in MS. Over the past decade, a large number of studies investigated sncRNAs in MS patients, focusing primarily on microRNAs (miRNAs). Overwhelming 500 miRNAs have been reported as dysregulated in MS. Nevertheless, owing to a large heterogeneity between studies it is challenging to evaluate the reproducibility of findings, in turn hampering our knowledge about the functional roles of miRNAs in disease. We systematically searched main databases and evaluated results from all studies that examined sncRNAs in MS to date (n = 61) and provided a detailed overview of experimental design and findings of these studies. We focused on the mechanisms of the most dysregulated sncRNAs and used predicted targets of the most dysregulated sncRNAs as input for functional enrichment analysis to highlight affected pathways. The prime affected pathway was TGF-β signaling. This multifunctional cytokine is important in the differentiation and function of T helper type 17 (Th17) and regulatory T (Treg) cells, with opposing functions in the disease. Recent studies demonstrate the importance of miRNAs in controlling the balance between Th17/Th1 cells and Tregs and, importantly, the potential to exploit this paradigm for therapeutic purposes. Additionally, some of the discussed miRNAs could potentially serve as biomarkers of disease. In order to assist researchers in evaluating the evidence of a particular sncRNA in the pathogenesis of MS, we provide a detailed overview of experimental design and findings of these studies to date.

Cytokine Targeting by miRNAs in Autoimmune Diseases

Persistent and excessive cytokine production is a hallmark of autoimmune diseases and may play a role in disease pathogenesis and amplification. Therefore, cytokine neutralization is a useful therapeutic strategy to treat immune-mediated conditions. MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression in diverse biological processes. Altered miRNA levels are observed in most autoimmune diseases and are recognized to influence autoimmunity through different mechanisms. Here, we review the impact of altered miRNA levels on the expression of cytokines that play a relevant pathogenic role in autoimmunity, namely primary pro-inflammatory cytokines, the IL-17/IL-23 axis, type I interferons and IL-10. Regulation can be either “direct” on the target cytokine, or “indirect,” meaning that one given miRNA post-transcriptionally regulates the expression of a protein that in turn influences the level of the cytokine. In addition, miRNAs associated with extracellular vesicles can regulate cytokine production in neighboring cells, either post-transcriptionally or via the stimulation of innate immune RNA-sensors, such as Toll-like receptors. Because of their tremendous potential as physiological and pathological regulators, miRNAs are in the limelight as promising future biopharmaceuticals. Thus, these studies may lead in the near future to the design and testing of therapeutic miRNAs as next generation drugs to target pathogenic cytokines in autoimmunity.

High expression of RAB38 promotes malignant progression of pancreatic cancer

Ras-Related Protein Rab-38 (RAB38), which belongs to the RAB family, is involved in the biogenesis of lysosome-related organelles and defense against certain microbial infections. However, the clinical significance and potential function of RAB38 in pancreatic adenocarcinoma remain unclear. In the present study, an immunohistochemical assay was performed to analyze the expression of RAB38 in pancreatic adenocarcinoma tumor specimens from 82 patients, and the clinicopathological characteristics and survival rate of these patients were further examined. To validate the role of RAB38 in tumors, the effect of RAB38 on tumor cell proliferation, migration and invasion was assessed by establishing RAB38 knockdown cell lines. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to examine the expression levels of proteins associated with the cancer cell behavior. In addition, the inhibitory effect of RAB38 silencing on pancreatic cancer was examined in mice. The immunohistochemistry results revealed that RAB38 was upregulated and positively correlated with the grade of progression in pancreatic adenocarcinoma patients. Further investigation indicated that RAB38 downregulation significantly suppressed the proliferation, migration and invasive capacity of pancreatic cancer cells, as well as decreased the expression levels of Ki67, proliferating cell nuclear antigen, and matrix metalloproteinases 2 and 9. RAB38 silencing also inhibited the development of pancreatic cancer in vivo. Taken together, a high level of RAB38 was significantly associated with the malignant phenotypes of pancreatic cancer, suggesting that RAB38 may serve as a novel biomarker and a potential therapeutic target for pancreatic cancer.

MiRNAs and inflammatory bowel disease: An interesting new story

Inflammatory bowel disease (IBD), as a chronic and recurrent inflammatory disorder, is caused by a dysregulated and aberrant immune response to exposed environmental factors in genetically susceptible individuals. Despite huge efforts in determining the molecular pathogenesis of IBD, an increasing worldwide incidence of IBD has been reported. MicroRNAs (miRNAs) are a set of noncoding RNA molecules that are about 22 nucleotides long, and these molecules are involved in the regulation of the gene expression. By clarifying the important role of miRNAs in a number of diseases, their role was also considered in IBD; numerous studies have been performed on this topic. In this review, we attempt to summarize a number of studies and discuss some of the recent developments in the roles of miRNAs in the pathophysiology, diagnosis, and treatment of IBD.

Control of Immunoregulatory Molecules by miRNAs in T Cell Activation

MiRNA targeting of key immunoregulatory molecules fine-tunes the immune response. This mechanism boosts or dampens immune functions to preserve homeostasis while supporting the full development of effector functions. MiRNA expression changes during T cell activation, highlighting that their function is constrained by a specific spatiotemporal frame related to the signals that induce T cell-based effector functions. Here, we update the state of the art regarding the miRNAs that are differentially expressed during T cell stimulation. We also revisit the existing data on miRNA function in T cell activation, with a special focus on the modulation of the most relevant immunoregulatory molecules.

Roles of microRNAs in T cell immunity: Implications for strategy development against infectious diseases

T cell immunity plays a vital role in pathogen infections. MicroRNA (miRNAs) are small, single-stranded noncoding RNAs that regulate T cell immunity by targeting key transcriptional factors, signaling proteins, and cytokines associated with T cell activation, differentiation, and function. The dysregulation of miRNA expression in T cells may lead to specific immune responses and can provide new therapeutic opportunities against various infectious diseases. Here, we summarize recent studies that focus on the roles of miRNAs in T cell immunity and highlight miRNA functions in prevalent infectious diseases. Additionally, we also provide insights into the functions of extracellular vesicle miRNAs and attempt to delineate the mechanism of miRNA sorting into extracellular vesicles and their immunomodulatory functions. Moreover, methodologies and strategies for miRNA delivery against infectious diseases are summarized. Finally, potential strategies for miRNA-based therapies are proposed.

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.

GLK-IKKβ signaling induces dimerization and translocation of the AhR-RORγt complex in IL-17A induction and autoimmune disease

Retinoic-acid-receptor-related orphan nuclear receptor γt (RORγt) controls the transcription of interleukin-17A (IL-17A), which plays critical roles in the pathogenesis of autoimmune diseases. Severity of several human autoimmune diseases is correlated with frequencies of germinal center kinase-like kinase (GLK) (also known as MAP4K3)-overexpressing T cells; however, the mechanism of GLK overexpression-induced autoimmunity remains unclear. We report the signal transduction converging on aryl hydrocarbon receptor (AhR)-RORγt interaction to activate transcription of the IL-17A gene in T cells. T cell-specific GLK transgenic mice spontaneously developed autoimmune diseases with selective induction of IL-17A in T cells. In GLK transgenic T cells, protein kinase Cθ (PKCθ) phosphorylated AhR at Ser³⁶ and induced AhR nuclear translocation. AhR also interacted with RORγt and transported RORγt into the nucleus. IKKβ (inhibitor of nuclear factor κB kinase β)-mediated RORγt Ser⁴⁸⁹ phosphorylation induced the AhR-RORγt interaction. T cell receptor (TCR) signaling also induced the novel RORγt phosphorylation and subsequent AhR-RORγt interaction. Collectively, TCR signaling or GLK overexpression induces IL-17A transcription through the IKKβ-mediated RORγt phosphorylation and the AhR-RORγt interaction in T cells. Our findings suggest that inhibitors of GLK or the AhR-RORγt complex could be used as IL-17A-blocking agents for IL-17A-mediated autoimmune diseases.