The relevance of miRNA-21 in HSV-induced inflammation in a mouse model

The role of miRNAs in Behçet's disease

The symptoms of Behçet's disease (BD), a multisystemic condition with autoimmune and inflammation as hallmarks, include arthritis, recurring oral and vaginal ulcers, skin rashes and lesions, and involvement of the nervous, gastrointestinal, and vascular systems. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), may be important regulators of inflammation and autoimmune disease. These ncRNAs are essential to the physiological and pathophysiological disease course, and miRNA in particular has received significant attention for its role and function in BD and its potential use as a diagnostic biomarker in recent years. Although promising as therapeutic targets, miRNAs must be studied further to fully comprehend how miRNAs in BD act biologically.

High Expression Levels of miR-21-5p in Younger Hospitalized COVID-19 Patients Are Associated with Mortality and Critical Disease

In COVID-19, critical disease and invasive mechanical ventilation (IMV) increase the risk of death, mainly in patients over 60 years of age.

OBJECTIVES

To find the relationship between miR-21-5p and miR-146a-5p in terms of the severity, IMV, and mortality in hospitalized COVID-19 patients younger than 55 years of age.

METHODS

The patients were stratified according to disease severity using the IDSA/WHO criteria for severe and critical COVID-19 and subclassified into critical non-survivors and critical survivors.

RESULTS

Ninety-seven severe/critical COVID-19 patients were included; 81.3% of the deceased were male and 18.8% were female. Higher expression miR-21-5p levels were associated as follows: severe vs. critical disease (p = 0.007, FC = 0.498), PaO₂/FiO₂ index, mild vs. severe (p = 0.027, FC = 0.558), and survivors vs. non-survivors (p = 0.03, FC = 0.463). Moreover, we identified correlations with clinical variables: CRP (rho = -0.54, p < 0.001), D-dimer (rho = -0.47, p < 0.05), related to damage in the kidney (rho = 0.60, p < 0.001), liver (rho = 0.41, p < 0.05), and lung (rho = 0.54, p < 0.001). Finally, miR-21-5p thresholds were calculated according to severity (8.191), IMV (8.191), and mortality (8.237); these values increased the risk of developing a critical disease (OR = 4.19), the need for IMV (OR = 5.63), and death (OR = 6.00).

CONCLUSION

Increased expression levels of miR-21-5p are related to worse outcome of COVID-19 in younger hospitalized patients.

Eubacterium rectale Attenuates HSV-1 Induced Systemic Inflammation in Mice by Inhibiting CD83

The purpose of this study was to determine whether administration of the microorganism Eubacterium rectale (E. rectale) could regulate dendritic cell (DC) activation and systemic inflammation in herpes simplex virus type 1-induced Behçet's disease (BD). E. rectale, butyrate-producing bacteria, was administered to BD mice. Peripheral blood leukocytes (PBL) and lymph node cells were isolated and analyzed by flow cytometry. 16S rRNA metagenomic analysis was performed in the feces of mice to determine the differences in the composition of the microbial population between normal and BD mice. Serum cytokine levels were measured by enzyme-linked immunosorbent assay. The frequency of DC activation marker CD83 positive cells was significantly increased in PBL of BD mice. Frequencies of CD83+ cells were also significantly increased in patients with active BD. 16S rRNA metagenomic analysis revealed different gut microbiota composition between normal and BD mice. The administration of E. rectale to BD mice reduced the frequency of CD83+ cells and significantly increased the frequency of NK1.1+ cells with the improvement of symptoms. The co-administration of colchicine and E. rectale also significantly reduced the frequency of CD83+ cells. Differences in gut microbiota were observed between normal mice and BD mice, and the administration of E. rectale downregulated the frequency of CD83, which was associated with BD deterioration. These data indicate that E. rectale could be a new therapeutic adjuvant for BD management.

microRNA-21: a key modulator in oncogenic viral infections

Oncogenic viruses are associated with approximately 15% of human cancers. In viral infections, microRNAs play an important role in host-pathogen interactions. miR-21 is a highly conserved non-coding RNA that not only regulates the development of oncogenic viral diseases, but also responds to the regulation of intracellular signal pathways. Oncogenic viruses, including HBV, HCV, HPV, and EBV, co-evolve with their hosts and cause persistent infections. The upregulation of host miR-21 manipulates key cellular pathways to evade host immune responses and then promote viral replication. Thus, a better understanding of the role of miR-21 in viral infections may help us to develop effective genetically-engineered oncolytic virus-based therapies against cancer.

Implications of miRNAs on TGF-β/TAK1/mTOR pathway in mediating the renoprotective effects of pentoxifylline against cisplatin-induced nephrotoxicity in rats

Cisplatin (CIS)-mediated nephrotoxicity is induced via transforming growth factor-beta (TGF-β) and TGF-β-activated kinase (TAK1). TGF-β and TAK1 are known to interact with microRNA-let-7b and microRNA-26b, respectively. Additionally, TGF-β1 is reported to down-regulate the autophagy marker microtubule-associated protein 1 light chain 3-II (LC3-II) through upregulation of microRNA-34a. Pentoxifylline (PTX) anti-inflammatory effects are mediated via suppressing TGF-β and regulating mammalian target of rapamycin (mTOR). The current study aimed to investigate the involvement of microRNAs let-7b, 26b, and 34a, and the modulating impact of PTX on CIS-induced nephrotoxicity. Moreover, we aimed at examining the ability of PTX to interact with TGF-β receptor-1 (TGFβR-1), and TAK1, and examine its ability to downgrade the previously reported toxicities. Hence, the expression of the aforementioned microRNAs, and protein levels of TGFβR-1, TGF-β1, TAK1, mTOR, LC3-II, and NF-κB were assessed. Molecular docking studies of PTX on TGFβR-1 and TAK1 were also executed. CIS induced TGF-β1, with down-regulation of microRNA-let-7b and -26b, and up-regulation of microRNA-34a. TGFβR-1, TAK1, and mTOR levels were increased, while LC3-II level was decreased. PTX significantly protected renal cells against CIS-induced changes as indicated by reverting the level of the investigated parameters, while exhibiting an antagonistic effect on TGFβR-1 and TAK1. Our results postulate a possible role of epigenetic regulation of CIS-induced nephrotoxicity through the investigated microRNAs proposing them as potential future targets for controlling this serious toxicity. PTX was able to shield CIS-induced toxicity possibly through blocking TGF-β pathway, while promoting autophagy in a TAK1 independent manner with the involvement of the examined microRNAs.

Immunomodulatory role for MicroRNAs: Regulation of PD-1/PD-L1 and CTLA-4 immune checkpoints expression

The development and progression of different pathologies including, cancer, are associated with suppressed immune responses. This restrained immune activity could be associated with the activation of different immune checkpoint pathways that mediate immunosuppressive functions. Therapeutic Protocols based on abolishing the activity of immune check points provided a promising potential for treating cancer. Among the distinct known immune checkpoints, PD-1/PD-L1 and CTLA-4, are the most studied and have been the focus for development of different blocking agents. Monoclonal antibodies that can block PD-1, PD-L1 or CTLA4 have been approved for treatment of different cancers. MicroRNAs (miRNAs), short non-coding regulatory RNA molecules, could repress mRNA expression at a post-transcriptional level. Many miRNAs have been reported to modulate the expression of CTLA-4 and PD-1/PD-L1, either directly or indirectly, in multiple pathological cases, mainly cancer. In this review, after a brief introduction about T cell activation and immune checkpoints, the miRNAs regulating the expression of CTLA-4 and PD-1/PD-L1 are discussed with highlights on their role in cancer. Many of these miRNAs could serve as novel treatments in different types of cancer as detailed throughout the review.

The PD-1/PD-L pathway in rheumatic diseases

BACKGROUND/PURPOSE

Autoimmune diseases are diseases in which the body produces an abnormal immune response to self-antigens and damages its own tissues. Programmed death-1 (PD-1) and its ligands (PD-Ls) have been discovered to be important negative regulators of the immune system, playing crucial roles in autoimmunity.

METHODS

We analyzed the existing scientific literature dealing with this issue. In this review, the PD-1/PD-L pathway in the genetic susceptibility to and pathogenesis of rheumatic diseases is discussed. The PD-1/PD-L pathway might be helpful for diagnosing, evaluating the disease activity of and treating rheumatic diseases.

RESULTS

PD-1/PD-L gene polymorphisms are associated with a genetic predisposition to rheumatic disorders, which can provide reference information for diagnosis and disease activity. The conclusion of the crucial role of the PD-1/PD-L pathway in the pathogenesis of rheumatic diseases is consistent, but the details remain controversial. In some animal models, manipulating the PD-1/PD-L pathway could decrease disease severity. PD-1/PD-Ls may enable us to develop new therapeutics for patients with rheumatic diseases in the future.

CONCLUSION

The PD-1/PD-L pathway plays crucial roles in rheumatic disease. More work is needed to provide a better mechanistic understanding of the PD-1/PD-L pathway and to facilitate the precise therapeutic manipulation of this pathway.

Past and Present Behçet's Disease Animal Models

Behçet's disease (BD) is presumably an autoinflammatory disease of unknown etiology for which several animal models have been described over the years. Agents and methods used for the development of these models have ranged from the herpes simplex type one virus (hsv-1) pathogen to the use of transgenic mice. Other models have also been used to investigate a possible autoimmune component. Each model possesses its own unique set of benefits and shortcomings, with no one model fully being able to recapitulate the disease phenotype. Here, we review the proposed models and provide commentary on their effectiveness and usefulness in studying the disease.

Regulation of PD-1/PD-L1 Pathway in Cancer by Noncoding RNAs

Immune checkpoint blockade has demonstrated significant anti-tumor immunity in an array of cancer types, yet the underlying regulatory mechanism of it is still obscure, and many problems remain to be solved. As an inhibitory costimulatory signal of T-cells, the programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway can paralyze T-cells at the tumor site, enabling the immune escape of tumor cells. Although many antibodies targeting PD-1/PD-L1 have been developed to block their interaction for the treatment of cancer, the reduced response rate and resistance to the therapies call for further comprehension of this pathway in the tumor microenvironment. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are two main types of noncoding RNAs that play critical parts in the regulation of immune response in tumorigenesis, including the PD-1/PD-L1 pathway. Here we summarize the most recent studies on the control of this pathway by noncoding RNAs in cancer and hopefully will offer new insights into immune checkpoint blockade therapies.

The role of CCR1 and therapeutic effects of anti-CCL3 antibody in herpes simplex virus-induced Behçet's disease mouse model

Behçet's disease (BD) is a chronic systemic inflammatory disease with unclear etiopathogenesis. Although gene variants of CC chemokine receptor type 1 (CCR1) have been reported, the protein expression of CCR1 in patients with BD remains unclear. The objective of this study was to analyze the frequencies of CCR1⁺ cells in a herpes simplex virus‐induced mouse model of BD. The frequencies of CCR1⁺ cells on the surface and in the cytoplasm of peripheral blood mononuclear cells and lymph nodes were analyzed by flow cytometry. The CCR1⁺ cells were significantly down‐regulated in BD mice compared with the normal control and symptom‐free control mice. Colchicine and pentoxifylline treatment improved the symptoms of BD and increased the frequencies of CCR1⁺ cells in BD mice. Treatment with chemokine CC motif ligand 3 (CCL3), a ligand of CCR1, caused BD symptoms to deteriorate in 10 of 16 BD mice (62·5%) via down‐regulation of CCR1⁺ cells. Anti‐CCL3 antibody treatment ameliorated BD symptoms in 10 of 20 mice (50%) and significantly decreased the disease severity score compared with CCL3‐treated BD mice (P = 0·01) via up‐regulation of CCR1⁺ cell frequencies. In patients with BD, plasma levels of CCL3 in an active state were significantly higher than in healthy control individuals (P = 0·02). These results show that the up‐regulation of CCR1⁺ cells was related to the control of systemic inflammation of BD in mouse models.

Herpes Simplex Virus 1 Deregulation of Host MicroRNAs

Viruses utilize microRNAs (miRNAs) in a vast variety of possible interactions and mechanisms, apparently far beyond the classical understanding of gene repression in humans. Likewise, herpes simplex virus 1 (HSV-1) expresses numerous miRNAs and deregulates the expression of host miRNAs. Several HSV-1 miRNAs are abundantly expressed in latency, some of which are encoded antisense to transcripts of important productive infection genes, indicating their roles in repressing the productive cycle and/or in maintenance/reactivation from latency. In addition, HSV-1 also exploits host miRNAs to advance its replication or repress its genes to facilitate latency. Here, we discuss what is known about the functional interplay between HSV-1 and the host miRNA machinery, potential targets, and the molecular mechanisms leading to an efficient virus replication and spread.

Regulatory Role of rno-miR-30b-5p in IL-10 and Toll-like Receptor 4 Expressions of T Lymphocytes in Experimental Autoimmune Uveitis In Vitro

Uveitis is a serious eye disease that usually damages young adult's health. MicroRNAs (miRNAs) are a class of small noncoding RNAs which regulate messenger RNA (mRNA) expression. It is predicted that rno-miR-30b-5p can regulate the expressions of interleukin-10 (IL-10) and Toll-like receptor 4 (TLR4). In this study, the regulatory role of rno-miR-30b-5p in IL-10 and TLR4 gene expressions was validated using luciferase activity assay. Further, the inflammatory manifestation of the anterior segment and pathological examination of the eye were explored in experimental autoimmune uveitis (EAU) rats. Meanwhile, the levels of rno-miR-30b-5p in eye tissues, spleen, and lymph nodes were measured using quantitative PCR (Q-PCR). IL-10 and TLR4 in spleen and lymph nodes were further separately determined by using Q-PCR and Enzyme-Linked Immunosorbent Assay (ELISA). Moreover, rno-miR-30b-5p mimic and its inhibitor were separately transfected into purified T cells, and the levels of IL-10 and TLR4 were detected using PCR, flow cytometry, and ELISA techniques. Results indicate that rno-miR-30b-5p was downregulated in spleen, lymph nodes, and eye tissues whereas the expressions of IL-10 and TLR4 at mRNA and protein levels were upregulated. The levels of IL-10 and TLR4 were negatively correlated to rno-miR-30b-5p levels. The result of in vitro cell transfection experiment indicates that IL-10 and TLR4 expressions were inhibited at mRNA and protein levels after T cells incubated with rno-miR-30b-5p mimic. However, the IL-10 and TLR4 mRNA levels were upregulated in purified T cells from spleen and lymph nodes after treatment with miR-30b-5p antagonist. In addition, there was no evident change of IL-10 and TLR4 proteins in spleen and lymph node T cells between EAU control and negative treatment groups. Flow cytometry analysis revealed that rno-miR-30b-5p mimic could reduce the number of both IL-10 and TLR4 positive cells, whereas rno-miR-30b-5p inhibitor could increase the number of IL-10 and TLR4 positive cells. Our study demonstrates that rno-miR-30b-5p influences the development of uveitis by regulating the level of IL-10 and TLR4 positive cells, thereby playing a role in the pathogenesis of uveitis.

HSV-Induced Systemic Inflammation as an Animal Model for Behçet's Disease and Therapeutic Applications

Behçet’s disease (BD) affects multiple organs. It is mainly characterized by recurrent oral, skin, and genital aphthous ulcers, and eye involvement. Successful management of BD is increasing, although its etiology remains unclear. A number of etiologies have been proposed, including environmental, genetic, viral, and immunological factors. To understand its complex etiology and improve its management, animal models of BD have been used to enable more effective therapeutic applications with increased clinical significance. An herpes simplex virus (HSV) type 1-induced BD mouse model has shown disease characteristics similar to those seen in BD patients. An HSV-induced BD animal model has been used to test various therapeutic modalities. The applied modalities are several materials that are derived from natural products, conventional therapeutics, and possible biologics. In this review, we provided how they regulate inflammation in an HSV-induced BD model.

The microRNA miR-21 conditions the brain to protect against ischemic and traumatic injuries

Ischemic and traumatic injuries to CNS remain leading causes of death and disability worldwide, despite decades of research into risk factors, therapies, and preventative measures. Recent studies showed that CNS injuries significantly alter the cerebral microRNAome that impact the secondary brain damage as well as plasticity and recovery. Many microRNA based therapies are currently in various clinical trials for different pathologic conditions indicating their therapeutic potential. In the present review, we discuss the role of miR-21 in acute CNS injuries which is currently thought to be a potent neuroprotective microRNA. We emphasize on the potential of miR-21 in promoting cell and tissue survival and preventing inflammation and apoptosis. We also discussed the role of miR-21 in conditioning the brain to promote ischemic tolerance. Finally, we discussed some of the challenges and difficulties to develop miR-21 as a neuroprotective therapy in humans.

MicroRNA-21 Limits Uptake of Listeria monocytogenes by Macrophages to Reduce the Intracellular Niche and Control Infection

MiRNAs are important post-transcriptional regulators of gene expression. MiRNA expression is a crucial part of host responses to bacterial infection, however there is limited knowledge of their impact on the outcome of infections. We investigated the influence of miR-21 on macrophage responses during infection with Listeria monocytogenes, which establishes an intracellular niche within macrophages. MiR-21 is induced following infection of bone marrow-derived macrophages (BMDMs) with Listeria. MiR-21^−/− macrophages display an increased bacterial burden with Listeria at 30 min and 2 h post-infection. This phenotype was reversed by the addition of synthetic miR-21 mimics to the system. To assess the immune response of wildtype (WT) and miR-21^−/− macrophages, BMDMs were treated with bacterial LPS or infected with Listeria. There was no difference in IL-10 and IL-6 between WT and miR-21^−/− BMDMs in response to LPS or Listeria. TNF-α was increased in miR-21^−/− BMDMs stimulated with LPS or Listeria compared to WT macrophages. We next assessed the production of nitric oxide (NO), a key bactericidal factor in Listeria infection. There was no significant difference in NO production between WT and miR-21^−/− cells, indicating that the increased bacterial burden may not be due to impaired killing. As the increased bacterial load was observed early following infection (30 min), we questioned whether this is due to differences in uptake of Listeria by WT and miR-21^−/− macrophages. We show that miR-21-deficiency enhances uptake of FITC-dextran and FITC-Escherichia coli bioparticles by macrophages. The previously observed Listeria burden phenotype was ablated by pre-treatment of cells with the actin polymerization inhibitor cytochalasin-D. From analysis of miR-21 targets, we selected the pro-phagocytic regulators myristoylated alanine-rich C-kinase substrate (MARCKS) and Ras homolog gene family, member B (RhoB) for further investigation. MARCKS and RhoB are increased in miR-21^−/− BMDMs, correlating with increased uptake of Listeria. Finally, intra-peritoneal infection of mice with Listeria led to increased bacterial burden in livers of miR-21^−/− mice compared to WT mice. These findings suggest a possible role for miR-21 in regulation of phagocytosis during infection, potentially by repression of MARCKS and RhoB, thus serving to limit the availability of the intracellular niche of pathogens like L. monocytogenes.

Hidradenitis suppurativa treated with tetracycline in combination with colchicine: a prospective series of 20 patients

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder of the follicular epithelium.

OBJECTIVES

The objective of the present study was to evaluate the effectiveness of the combination of tetracycline with colchicine in the treatment of HS.

METHODS

Twenty patients (10 women and 10 men) with HS were included in an open, prospective, pilot study. All patients were treated with 100 mg minocycline administered orally once per day in combination with 0.5 mg colchicine administered twice per day for 6 months followed by a maintenance regimen of 0.5 mg colchicine administered orally twice per day for 3 months. Patients were examined at baseline and thereafter every 3 months for a total of 9 months. The efficacy of the treatment was evaluated using a physician's global assessment (PGA) scale, the Hurley scoring system, and the Dermatology Life Quality Index (DLQI).

RESULTS

A significant improvement in clinical manifestation was reflected in scores on the Hurley scoring system and DLQI. According to the PGA, patients achieved substantial improvement or complete remission. Clinically, all patients started to show signs of improvement within the first 3 months of therapy and continued to improve over the next 6 months.

CONCLUSIONS

This study indicates that the combination of the anti-inflammatory actions of colchicine and minocycline is effective in disease control in HS. Colchicine emerged as a safe option for the maintenance of the obtained result.

The role of microRNAs in enteroviral infections

The genus Enterovirus, a member of the Picornavirus family, are RNA viruses that can cause poliomyelitis, hand-food-mouth disease, viral meningitis or meningoencephalitis, viral myocarditis and so on. MicroRNAs are a class of highly conserved, small noncoding RNAs recognized as important regulators of gene expression. Recent studies found that MicroRNAs play a significant role in the infection of Enterovirus, such as enterovirus 71, coxsackievirus B3 and other Enterovirus. Enteroviral infection can alter the expression of cellular MicroRNAs, and cellular MicroRNAs can modulate viral pathogenesis and replication by regulating the expression level of viral or host's genes. Herein, this review summarizes the role of MicroRNAs in enteroviral infection.

Regulation of IL-17 in autoimmune diseases by transcriptional factors and microRNAs

In recent years, IL-17A (IL-17), a pro-inflammatory cytokine, has received intense attention of researchers and clinicians alike with documented effects in inflammation and autoimmune diseases. IL-17 mobilizes, recruits and activates different cells to increase inflammation. Although protective in infections, overproduction of IL-17 promotes inflammation in autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, psoriasis, among others. Regulating IL-17 levels or action by using IL-17-blocking antibodies or IL-17R antagonist has shown to attenuate experimental autoimmune diseases. It is now known that in addition to IL-17-specific transcription factor, RORγt, several other transcription factors and select microRNAs (miRNA) regulate IL-17. Given that miRNAs are dysregulated in autoimmune diseases, a better understanding of transcriptional factors and miRNA regulation of IL-17 expression and function will be essential for devising potential new therapies. In this review, we will overview IL-17 induction and function in relation to autoimmune diseases. In addition, current findings on transcriptional regulation of IL-17 induction and plausible interplay between IL-17 and miRNA in autoimmune diseases are highlighted.

Down-Regulation of miR-146a Expression Induces Allergic Conjunctivitis in Mice by Increasing TSLP Level

Background

Pollen is the most common aeroallergen to cause conjunctivitis. In this study, we established a short ragweed (SRW)-induced mouse model of allergic conjunctivitis (AC) and aimed to explore the potential role of miR-146a and its downstream molecules in the development of ocular allergic inflammation.

Material/Methods

The mouse model of challenge pollen was used for in vivo study. The culture model of primary human limbal epithelium (HLE) exposed to lipopolysaccharide (LPS) was performed for in vitro research. The numbers of eosinophils and total inflammatory cells were examined using Giemsa staining. The expression of mRNA and miR-146a was determined by quantitative RT-PCR, and protein production was evaluated by Western blotting.

Results

In vivo of mice, pollen challenge induced conjunctiva inflammatory response indicated by increased number of eosinophils and total inflammatory cells. Interestingly, pollen significantly attenuated miR-146a expression while it enhanced expression of thymic stromal lymphopoietin (TSLP) and its downstream molecules, including TSLP receptor (TSLPR)/ OX40 ligand (OX40L)/CD11C. In vitro of HCE, downregulation effect of miR-146a expression induced by LPS was reversed by Bay treatment, an inhibitor for nuclear factor kappa B (NF-κB), and LPS-induced cell inflammation is mediated by miR-146a-TSLP/TSLPR/OX40L/CD11C signaling pathway. This was further demonstrated by overexpression of miR-146a in mouse abrogated pollen-triggered conjunctiva inflammatory reaction as well as pollen-induced activity of TSLP/TSLPR/OX40L/CD11C signaling.

Conclusions

Down-regulation of miR-146a expression induces allergic conjunctivitis in mice by increasing TSLP level.