Transcriptomics identified a critical role for Th2 cell-intrinsic miR-155 in mediating allergy and antihelminth immunity

The role of microRNAs in atopic dermatitis

Atopic dermatitis (AD), known as eczema, is a chronic inflammatory skin condition affecting millions worldwide. This abstract provides an overview of the clinical features and underlying pathogenesis of AD, highlighting the role of specific microRNAs (miRNAs) in its development and progression. AD presents with distinct clinical manifestations that evolve with age, starting in infancy with dry, itchy skin and red patches, which can lead to sleep disturbances. In childhood, the rash spreads to flexural areas, resulting in lichenification. In adulthood, lesions may localize to specific areas, including the hands and eyelids. Pruritus (itchiness) is a hallmark symptom, often leading to excoriations and increased vulnerability to skin infections. The pathogenesis of AD is multifaceted, involving genetic, immunological, and environmental factors. Skin barrier dysfunction, immune dysregulation, genetic predisposition, microbiome alterations, and environmental triggers contribute to its development. Recent research has uncovered the role of miRNAs, such as miR-10a-5p, miR-29b, miR-124, miR-143, miR-146a-5p, miR-151a, miR-155, and miR-223, in AD pathogenesis. These microRNAs play crucial roles in regulating various aspects of immune responses, keratinocyte dynamics, and inflammation. MicroRNA-10a-5p orchestrates keratinocyte proliferation and differentiation, while miR-29b regulates keratinocyte apoptosis and barrier integrity. MicroRNA-124 exhibits anti-inflammatory effects by targeting the NF-κB signaling pathway. MicroRNANA-143 counters allergic inflammation by modulating IL-13 signaling. MicroRNA-146a-5p regulates immune responses and correlates with IgE levels in AD. MicroRNA-151a shows diagnostic potential and modulates IL-12 receptor β2. MicroRNA-155 plays a central role in immune responses and Th17 cell differentiation, offering diagnostic and therapeutic potential. MicroRNA-223 is linked to prenatal smoke exposure and immune modulation in AD. Understanding these microRNAs' intricate roles in AD pathogenesis promises more effective treatments, personalized approaches, and enhanced diagnostic tools. Further research into these molecular orchestrators may transform the landscape of AD management, improving the quality of life for affected individuals.

Non-coding RNAs in disease: from mechanisms to therapeutics

Non-coding RNAs (ncRNAs) are a heterogeneous group of transcripts that, by definition, are not translated into proteins. Since their discovery, ncRNAs have emerged as important regulators of multiple biological functions across a range of cell types and tissues, and their dysregulation has been implicated in disease. Notably, much research has focused on the link between microRNAs (miRNAs) and human cancers, although other ncRNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are also emerging as relevant contributors to human disease. In this Review, we summarize our current understanding of the roles of miRNAs, lncRNAs and circRNAs in cancer and other major human diseases, notably cardiovascular, neurological and infectious diseases. Further, we discuss the potential use of ncRNAs as biomarkers of disease and as therapeutic targets.

Lung proinflammatory microRNA and cytokine expression in a mouse model of allergic inflammation: role of sex chromosome complement and gonadal hormones

Epigenetic alterations such as dysregulation of miRNAs have been reported to play important roles in interactions between genetic and environmental factors. In this study, we tested the hypothesis that induction of lung inflammation by inhaled allergens triggers a sex-specific miRNA regulation that is dependent on chromosome complement and hormonal milieu. We challenged the four core genotypes (FCGs) model through intranasal sensitization with a house dust mite (HDM) solution (or PBS as a control) for 5 wk. The FCG model allows four combinations of gonads and sex chromosomes: 1) XX mice with ovaries (XXF), 2) XY mice with testes (XYM), 3) XX mice with testes (XXM), and 4) XY mice with ovaries (XYF). Following the challenge (n = 5-7/group), we assessed the expression of 84 inflammatory miRNAs in lung tissue using a PCR array and cytokine levels in bronchoalveolar lavage fluid (BAL) by a multiplex protein assay (n = 4-7 animals/group). Our results showed higher levels of the chemokine KC (an Il-8 homolog) and IL-7 in BAL from XYF mice challenged with HDM. In addition, IL-17A was significantly higher in BAL from both XXF and XYF mice. A three-way interaction among treatment, gonads, and sex chromosome revealed 60 of 64 miRNAs that differed in expression depending on genotype; XXF, XXM, XYF, and XYM mice had 45, 32, 4, and 52 differentially expressed miRNAs, respectively. Regulatory networks of miRNAs identified in this study were implicated in pathways associated with asthma. Female gonadal hormonal effects may alter miRNA expression and contribute to the higher susceptibility of females to asthma.NEW & NOTEWORTHY miRNAs play important roles in regulating gene and environmental interactions. However, their role in mediating sex differences in allergic responses and lung diseases has not been elucidated. Our study used a targeted omics approach to characterize the contributions of gonadal hormones and chromosomal components to lung responses to an allergen challenge. Our results point to the influence of sex hormones in miRNA expression and proinflammatory markers in allergic airway inflammation.

Hypoxia-inducible microRNA-155 negatively regulates epithelial barrier in eosinophilic esophagitis by suppressing tight junction claudin-7

MicroRNA (miRNA)-mediated mRNA regulation directs many homeostatic and pathological processes, but how miRNAs coordinate aberrant esophageal inflammation during eosinophilic esophagitis (EoE) is poorly understood. Here, we report a deregulatory axis where microRNA-155 (miR-155) regulates epithelial barrier dysfunction by selectively constraining tight junction CLDN7 (claudin-7). MiR-155 is elevated in the esophageal epithelium of biopsies from patients with active EoE and in cell culture models. MiR-155 localization using in situ hybridization (ISH) in patient biopsies and intra-epithelial compartmentalization of miR-155 show expression predominantly within the basal epithelia. Epithelial miR-155 activity was evident through diminished target gene expression in 3D organotypic cultures, particularly in relatively undifferentiated basal cell states. Mechanistically, generation of a novel cell line with enhanced epithelial miR-155 stable overexpression induced a functionally deficient epithelial barrier in 3D air-liquid interface epithelial cultures measured by transepithelial electrical resistance (TEER). Histological assessment of 3D esophageal organoid cultures overexpressing miR-155 showed notable dilated intra-epithelial spaces. Unbiased RNA-sequencing analysis and immunofluorescence determined a defect in epithelial barrier tight junctions and revealed a selective reduction in the expression of critical esophageal tight junction molecule, claudin-7. Together, our data reveal a previously unappreciated role for miR-155 in mediating epithelial barrier dysfunction in esophageal inflammation.

Loss of TRIM24 promotes IL-10 expression via CBP/p300-dependent IFNβ1 transcription during macrophage activation

BACKGROUND

As an anti-inflammatory cytokine, interleukin 10 (IL-10) plays a vital role in preventing inflammatory and autoimmune pathologies while also maintaining immune homeostasis. IL-10 production in macrophages is tightly regulated by multiple pathways. TRIM24, a member of the Transcriptional Intermediary Factor 1 (TIF1) family, contributes to antiviral immunity and macrophage M2 polarization. However, the role of TRIM24 in regulating IL-10 expression and its involvement in endotoxic shock remains unclear.

METHODS

In vitro, bone marrow derived macrophages cultured with GM-CSF or M-CSF were stimulated with LPS (100ng/ml). Murine models of endotoxic shock were established by challenging the mice with different dose of LPS (i.p). RTPCR, RNA sequencing, ELISA and hematoxylin and eosin staining were performed to elucidate the role and mechanisms of TRIM24 in endotoxic shock.

RESULTS

The expression of TRIM24 is downregulated in LPS-stimulated bone marrow-derived macrophages (BMDMs). Loss of TRIM24 boosted IL-10 expression during the late stage of LPS-stimulation in macrophages. RNA-seq analysis revealed the upregulation of IFNβ1, an upstream regulator of IL-10, in TRIM24 knockout macrophages. Treatment with C646, a CBP/p300 inhibitor, diminished the difference in both IFNβ1 and IL-10 expression between TRIM24 knockout and control macrophages. Loss of TRIM24 provided protection against LPS-induced endotoxic shock in mice.

CONCLUSION

Our results demonstrated that inhibiting TRIM24 promoted the expression of IFNβ1 and IL-10 during macrophage activation, therefore protecting mice from endotoxic shock. This study offers novel insights into the regulatory role of TRIM24 in IL-10 expression, making it a potentially attractive therapeutic target for inflammatory diseases.

Trained innate immunity, epigenetics, and food allergy

In recent years the increased incidence of food allergy in Western culture has been associated with environmental factors and an inappropriate immune phenotype. While the adaptive immune changes in food allergy development and progression have been well-characterized, an increase in innate cell frequency and activation status has also recently received greater attention. Early in prenatal and neonatal development of human immunity there is a reliance on epigenetic and metabolic changes that stem from environmental factors, which are critical in training the immune outcomes. In the present review, we discuss how trained immunity is regulated by epigenetic, microbial and metabolic factors, and how these factors and their impact on innate immunity have been linked to the development of food allergy. We further summarize current efforts to use probiotics as a potential therapeutic approach to reverse the epigenetic and metabolic signatures and prevent the development of severe anaphylactic food allergy, as well as the potential use of trained immunity as a diagnostic and management strategy. Finally, trained immunity is presented as one of the mechanisms of action of allergen-specific immunotherapy to promote tolerogenic responses in allergic individuals.

Crosstalk of Transcriptional Regulators of Adaptive Immune System and microRNAs: An Insight into Differentiation and Development

MicroRNAs (miRNAs), as small regulatory RNA molecules, are involved in gene expression at the post-transcriptional level. Hence, miRNAs contribute to gene regulation of various steps of different cell subsets' differentiation, maturation, and activation. The adaptive immune system arm, which exhibits the most specific immune responses, is also modulated by miRNAs. The generation and maturation of various T-cell subsets concomitant with B-cells is under precise regulation of miRNAs which function directly on the hallmark genes of each cell subset or indirectly through regulation of signaling pathway mediators and/or transcription factors involved in this maturation journey. In this review, we first discussed the origination process of common lymphocyte progenitors from hematopoietic stem cells, which further differentiate into various T-cell subsets under strict regulation of miRNAs and transcription factors. Subsequently, the differentiation of B-cells from common lymphocyte progenitors in bone marrow and periphery were discussed in association with a network of miRNAs and transcription factors.

Studies on the role of non-coding RNAs in controlling the activity of T cells in asthma

Bronchial asthma, commonly known as asthma, is a chronic inflammatory disease characterized by airway inflammation, increased responsiveness and changes in airway structure. T cells, particularly T helper cells, play a crucial role in the disease. Non-coding RNAs, which are RNAs that do not code for proteins, mainly include microRNAs, long non-coding RNAs, and circular RNAs, play a role in regulating various biological processes. Studies have shown that non-coding RNAs have an important role in the activation and transformation of T cells and other biological processes in asthma. The specific mechanisms and clinical applications are worth further examination. This article reviews the recent research on the role of microRNAs, long non-coding RNAs and circular RNAs in T cells in asthma.

Expression and diagnostic value of miR-142-5p and miR-155-5p in the serum of children with allergic rhinitis

BACKGROUND

Recent studies have demonstrated that microRNAs (miRNAs) play an essential role in the regulation of allergic rhinitis (AR), but the underlying mechanism is still unclear.

OBJECTIVE

This case-control study aimed to measure the expression levels of serum miRNAs in children with AR, to evaluate their potential as diagnostic markers, and investigate the association between miRNAs and IL-4, total nasal symptom score (TNSS), and specific IgE (Artemisia).

METHODS

Twenty allergic rhinitis patients and 20 healthy controls were included. The expression levels of serum miR-18a-5p, miR-142-5p, miR-155-5p, and miR-3687 were measured using quantitative real-time polymerase chain reaction. Serum cytokine levels were measured using IL-4 enzyme-linked immunosorbent assay kits. Nasal symptoms were assessed using the TNSS. A receiver operating characteristic (ROC) curve was used to test the diagnostic ability of the study parameters.

RESULTS

The AR case group had a higher serum expression of miR-142-5p, miR-155-5p, and IL-4 than did the control group. However, there were no significant differences in the serum miR-18a-5p and miR-3687 expression levels between the two groups. We found that serum miR-142-5p and miR-155-5p levels were positively correlated with the expression of specific IgE (Artemisia). TNSS did not correlate with miR-142-5p or miR-155-5p levels. In addition, no significant correlation was identified between miR-142-5p and IL-4 expression, whereas miR-155-5p was positively correlated with IL-4 expression. The receiver operating characteristic curve did not look promising. The AUC was around 0.7 and it was not high enough for diagnostic tool.

CONCLUSION

The expression levels of serum miR-142-5p and miR-155-5p were upregulated in children with AR; however, they were insufficient as diagnostic tools for AR. MiR-155-5p may be involved in T helper type 2 cell-mediated immune response.

The Immune Response to Nematode Infection

Nematode infection is a major threat to the health of humans, domestic animals and wildlife. Nematodes vary in their effect on the host and in the mechanisms underlying immunity but the general features are becoming clear. There is considerable variation among individuals in resistance to infection and much of this variation is due to genetic variation in the immune response. The major histocompatibility complex has a strong influence on resistance to infection but other genes are collectively more important. Resistant individuals produce more IgA, eosinophils, IgE and mast cells than susceptible individuals and this is a consequence of stronger type 2 (Th2) immune responses. A variety of factors promote Th2 responses including genetic background, diet, molecules produced by the parasite and the location of the infection. A variety of cells and molecules including proteins, glycolipids and RNA act in concert to promote responses and to regulate the response. Nematodes themselves also modulate the host response and over 20 parasite-derived immunomodulatory molecules have been identified. Different species of nematodes modulate the immune response in different ways and probably use multiple molecules. The reasons for this are unclear and the interactions among immunomodulators have still to be investigated.

Multi-omics reveals the mechanisms of DEHP driven pulmonary toxicity in ovalbumin-sensitized mice

The plasticizer di- (2-ethylhexyl) phthalate (DEHP) is considered a risk factor for allergic diseases and has attracted public attention for its adverse effects on health. However, respiratory adverse effects after DEHP exposure in food allergies have rarely been reported. MiRNAs are considered to be key regulators in the complex interrelationships between the host and microbiome and may be a potential factor involved in DEHP-induced pulmonary toxicity. To investigate the adverse effects of DEHP on the lung during sensitization, we established an ovalbumin (OVA)-sensitized mouse model exposed to DEHP and performed 16S rDNA gene sequencing, miRNA sequencing, and correlation analysis. Our results showed that DEHP aggravated the immune disorder in OVA-sensitized mice, which was mainly characterized by an increase in the proportion of Th2 lymphocytes, and further enhanced OVA-induced airway inflammation without promoting pulmonary fibrosis. Compared with the OVA group, DEHP interfered with the lung microbial community, making Proteobacteria the dominant phylum, while Bacteroidetes were significantly reduced. Differentially expressed miRNAs were enriched in the PI3K/AKT pathway, which was closely related to immune function and airway inflammation. The expression of miR-146b-5p was elevated in the DEHP group, which was positively correlated with the proportion of Th2 cells and significantly negatively correlated with the abundance of Bacteroidetes. The results indicate that DEHP may interfere with the expression of miR-146b-5p, affect the composition of the lung microbiota, induce an imbalance in T cells, and lead to immune disorders and airway inflammation. The current study uses multi-omics to reveal the potential link between the plasticizer DEHP and allergic diseases and provides new insights into the ecotoxicology of environmental exposures to DEHP.

Mir155 regulates osteogenesis and bone mass phenotype via targeting S1pr1 gene

MicroRNA-155 (miR155) is overexpressed in various inflammatory diseases and cancer, in which bone resorption and osteolysis are frequently observed. However, the role of miR155 on osteogenesis and bone mass phenotype is still unknown. Here, we report a low bone mass phenotype in the long bone of Mir155-Tg mice compared with wild-type mice. In contrast, Mir155-KO mice showed a high bone mass phenotype and protective effect against inflammation-induced bone loss. Mir155-KO mice showed robust bone regeneration in the ectopic and orthotopic model, but Mir155-Tg mice showed compromised bone regeneration compared with the wild-type mice. Similarly, the osteogenic differentiation potential of bone marrow stromal stem cells (BMSCs) from Mir155-KO mice was robust and Mir155-Tg was compromised compared with that of wild-type mice. Moreover, Mir155 knockdown in BMSCs from wild-type mice showed higher osteogenic differentiation potential, supporting the results from Mir155-KO mice. TargetScan analysis predicted sphingosine 1-phosphate receptor-1 (S1pr1) as a target gene of Mir155, which was further confirmed by luciferase assay and Mir155 knockdown. S1pr1 overexpression in BMSCs robustly promoted osteogenic differentiation without affecting cell viability and proliferation. Furthermore, osteoclastogenic differentiation of Mir155-Tg bone marrow-derived macrophages was inhibited compared with that of wild-type mice. Thus, Mir155 showed a catabolic effect on osteogenesis and bone mass phenotype via interaction with the S1pr1 gene, suggesting inhibition of Mir155 as a potential strategy for bone regeneration and bone defect healing.

MicroRNAs in T Cell-Immunotherapy

MicroRNAs (miRNAs) act as master regulators of gene expression in homeostasis and disease. Despite the rapidly growing body of evidence on the theranostic potential of restoring miRNA levels in pre-clinical models, the translation into clinics remains limited. Here, we review the current knowledge of miRNAs as T-cell targeting immunotherapeutic tools, and we offer an overview of the recent advances in miRNA delivery strategies, clinical trials and future perspectives in RNA interference technologies.

The Role of Systems Biology in Deciphering Asthma Heterogeneity

Asthma is one of the most common and lifelong and chronic inflammatory diseases characterized by inflammation, bronchial hyperresponsiveness, and airway obstruction episodes. It is a heterogeneous disease of varying and overlapping phenotypes with many confounding factors playing a role in disease susceptibility and management. Such multifactorial disorders will benefit from using systems biology as a strategy to elucidate molecular insights from complex, quantitative, massive clinical, and biological data that will help to understand the underlying disease mechanism, early detection, and treatment planning. Systems biology is an approach that uses the comprehensive understanding of living systems through bioinformatics, mathematical, and computational techniques to model diverse high-throughput molecular, cellular, and the physiologic profiling of healthy and diseased populations to define biological processes. The use of systems biology has helped understand and enrich our knowledge of asthma heterogeneity and molecular basis; however, such methods have their limitations. The translational benefits of these studies are few, and it is recommended to reanalyze the different studies and omics in conjugation with one another which may help understand the reasons for this variation and help overcome the limitations of understanding the heterogeneity in asthma pathology. In this review, we aim to show the different factors that play a role in asthma heterogeneity and how systems biology may aid in understanding and deciphering the molecular basis of asthma.

Extracellular vesicles in respiratory disease

Extracellular vesicles (EVs) are membranous nanoparticles secreted by nearly all cell types and play a critical role in cell-to-cell crosstalk. EVs can be categorized based on their size, surface markers, or the cell type from which they originate. EVs carry "cargo," including but not limited to, RNA, DNA, proteins, and small signaling molecules. To date, many methods have been developed to isolate EVs from biological fluids, such as blood plasma, urine, bronchoalveolar lavage fluid, and urine. Once isolated, EVs can be characterized by dynamic light scattering, nanotracking analysis, nanoscale flow cytometry, and transmission electron microscopy. Given the ability of EVs to transport cargo between cells, research has recently focused on understanding their role in various human diseases. As understanding of their significance to disease processes grows, insight into the mechanisms behind the physiological role of their cargo in target cells can facilitate the development of a new type of biomarker and therapeutic target for diseases in future. In addition, their ability to deliver their cargo selectively to target cells within the human body means that they could serve as therapeutic agents or methods of drug delivery. In this review, we will first introduce EVs and the cargo they carry, outline current methods for EV isolation and characterization, and discuss their potential use as biomarkers and therapeutic agents in the near future.

Activated CLL cells regulate IL17F producing Th17 cells in miR155 dependent and outcome specific manners

Chronic lymphocytic leukemia (CLL) results from expansion of a CD5+ B-cell clone that requires interactions with other cell types, including T cells. Moreover, CLL patients have elevated circulating IL17A+ and IL17F+ CD4+ T cells (Th17s), with higher IL17A+Th17s correlating with better outcomes. We report that CLL Th17s express more miR155, a Th17 differentiation regulator, than control Th17s, despite naïve CD4+ T cell (TN) basal miR155 levels being similar in both. We also found that CLL cells directly regulate miR155 levels in TN, thereby affecting Th17 differentiation by documenting that: co-culturing TN with resting (Brest) or activated (Bact) CLL cells alters the magnitude and direction of T-cell miR155 levels; CLL Bact promote IL17A+ and IL17F+ T cell generation by a miR155-dependent mechanism, confirmed by miR155 inhibition; co-cultures of TN with CLL Bact lead to a linear correlation between the degree and direction of T-cell miR155 expression changes and IL17F production, but not IL17A; Bact-mediated changes in TN miR155 expression correlate with outcome, irrespective of IGHV mutation status, a strong prognostic indicator. Together, the results identify a previously unrecognized CLL Bact-dependent mechanism, upregulation of TN miR155 expression and subsequent enhancement of IL17F+ Th17 generation, that favors better clinical courses.

T cell-intrinsic miR-155 is required for Th2 and Th17-biased responses in acute and chronic airway inflammation by targeting several different transcription factors

Asthmatic airway inflammation is divided into two typical endotypes: Th2-mediated eosinophilic and Th1- or Th17-mediated neutrophilic airway inflammation. The miRNA miR-155 has well-documented roles in the regulation of adaptive T-cell responses and innate immunity. However, no specific cell-intrinsic role has yet been elucidated for miR-155 in T cells in the course of Th2-eosinophilic and Th17-neutrophilic airway inflammation using actual in vivo asthma models. Here, using conditional KO (miR155^ΔCD4 cKO) mice that have the specific deficiency of miR-155 in T cells, we found that the specific deficiency of miR-155 in T cells resulted in fully suppressed Th2-type eosinophilic airway inflammation following acute allergen exposure, as well as greatly attenuated the Th17-type neutrophilic airway inflammation induced by repeated allergen exposure. Furthermore, miR-155 in T cells appeared to regulate the expression of several different target genes in the functional activation of CD4+ Th2 and Th17 cells. To be more precise, the deficiency of miR-155 in T cells enhanced the expression of c-Maf, SOCS1, Fosl2, and Jarid2 in the course of CD4+ Th2 cell activation, while C/EBPβ was highly enhanced in CD4+ Th17 cell activation in the absence of miR-155 expression. Conclusively, our data revealed that miR-155 could promote Th2 and Th17-mediated airway inflammation via the regulation of several different target genes, depending on the context of asthmatic diseases. Therefore, these results provide valuable insights in actual understanding of specific cell-intrinsic role of miR-155 in eosinophilic and neutrophilic airway inflammation for the development of fine-tune therapeutic strategies.

miR-155: An Important Role in Inflammation Response

MicroRNAs (miRNAs) are a class of small, mature, noncoding RNA that lead to posttranscriptional gene silencing to regulate gene expression. miRNAs are instrumental in biological processes such as cell development, cell differentiation, cell proliferation, and cell apoptosis. The miRNA-mediated gene silencing is an important part of the regulation of gene expression in many kinds of diseases. miR-155, one of the best-characterized miRNAs, has been found to be closely related to physiological and pathological processes. What is more, miR-155 can be used as a potential therapeutic target for inflammatory diseases. We analyze the articles about miR-155 for nearly five years, review the advanced study on the function of miR-155 in different inflammatory cells like T cells, B cells, DCs, and macrophages, and then summarize the biological functions of miR-155 in different inflammatory cells. The widespread involvement of miR-155 in human diseases has led to a novel therapeutic approach between Chinese and Western medicine.

SJMHE1 Peptide from Schistosoma japonicum Inhibits Asthma in Mice by Regulating Th17/Treg Cell Balance via miR-155

Purpose

Helminths and their products can regulate immune response and offer new strategies to control and alleviate inflammation, including asthma. We previously found that a peptide named as SJMHE1 from Schistosoma japonicum can suppress asthma in mice. This study mainly investigated the molecular mechanism of SJMHE1 in inhibiting asthma inflammation.

Methods

SJMHE1 was administered to mice with OVA-induced asthma via subcutaneous injection, and its effects were detected by testing the airway inflammation of mice. The Th cell distribution was analyzed by flow cytometry. Th-related transcription factor and cytokine expression in the lungs of mice were analyzed using quantitative real-time PCR (qRT-PCR). The expression of miR-155 and levels of phosphorylated STAT3 and STAT5 were also determined after SJMHE1 treatment in mice by qRT-PCR and Western blot analysis. The in vitro mouse CD4⁺ T cells were transfected with lentivirus containing overexpressed or inhibited miR-155, and the proportion of Th17, Treg cells, CD4⁺p-STAT3⁺, and CD4⁺p-STAT5⁺ cells were analyzed by flow cytometry.

Results

SJMHE1 ameliorated the airway inflammation of asthmatic mice, upregulated the proportion of Th1 and Treg cells, and the expression of Th1 and Treg-related transcription factor and cytokines. Simultaneously, SJMHE1 treatment reduced the percentage of Th2 and Th17 cells and the expression of Th2 and Th17-related transcription factor and cytokines. SJMHE1 treatment decreased the expression of miR-155 and p-STAT3 but increased p-STAT5 expression. In vitro, the percentage of Th17 and CD4⁺p-STAT3⁺ cells increased in CD4⁺ T cells transfected over-expression of miR-155, but SJMHE1 inhibited the miR-155-mediated increase of Th17 cells. Furthermore, SJMHE1 increased the proportion of Treg and CD4⁺p-STAT5⁺ cells after transfected over-expression or inhibition of miR-155.

Conclusion

SJMHE1 regulated the balance of Th17 and Treg cells by modulating the activation of STAT3 and STAT5 via miR-155 in asthma. SJMHE1 might be a promising treatment for asthma.

Cell-intrinsic and -extrinsic roles of miRNAs in regulating T cell immunity

T cells are crucial to generate an effective response against numerous invading microbial pathogens and play a pivotal role in tumor surveillance and elimination. However, unwanted T cell activation can also lead to deleterious immune-mediated inflammation and tissue damage. To ensure that an optimal T cell response can be established, each step, beginning from T cell development in the thymus to their activation and function in the periphery, is tightly regulated by many transcription factors and epigenetic regulators including microRNAs (miRNAs). Here, we first summarize recent progress in identifying major immune regulatory miRNAs in controlling the differentiation and function of distinct T cell subsets. Moreover, as emerging evidence has demonstrated that miRNAs can impact T cell immunity through targeting both immune- and non-immune cell populations that T cells closely interact with, the T cell-extrinsic role of miRNAs in regulating different aspects of T cell biology is also addressed. Finally, we discuss the complex nature of miRNA-mediated control of T cell immunity and highlight important questions that remain to be further investigated.

Dual role of the miR-146 family in rhinovirus-induced airway inflammation and allergic asthma exacerbation

Rhinovirus (RV) infections are associated with asthma exacerbations. MicroRNA-146a and microRNA-146b (miR-146a/b) are anti-inflammatory miRNAs that suppress signaling through the nuclear factor kappa B (NF-κB) pathway and inhibit pro-inflammatory chemokine production in primary human bronchial epithelial cells (HBECs). In the current study, we aimed to explore whether miR-146a/b could regulate cellular responses to RVs in HBECs and airways during RV-induced asthma exacerbation. We demonstrated that expression of miR-146a/b and pro-inflammatory chemokines was increased in HBECs and mouse airways during RV infection. However, transfection with cell-penetrating peptide (CPP)-miR-146a nanocomplexes before infection with RV significantly reduced the expression of the pro-inflammatory chemokines CCL5, IL-8 and CXCL1, increased interferon-λ production, and attenuated infection with the green fluorescent protein (GFP)-expressing RV-A16 in HBECs. Concordantly, compared to wild-type (wt) mice, Mir146a/b-/- mice exhibited more severe airway neutrophilia and increased T helper (Th)1 and Th17 cell infiltration in response to RV-A1b infection and a stronger Th17 response with a less prominent Th2 response in house dust mite extract (HDM)-induced allergic airway inflammation and RV-induced exacerbation models. Interestingly, intranasal administration of CPP-miR-146a nanocomplexes reduced HDM-induced allergic airway inflammation without a significant effect on the Th2/Th1/Th17 balance in wild-type mice. In conclusion, the overexpression of miR-146a has a strong anti-inflammatory effect on RV infection in HBECs and a mouse model of allergic airway inflammation, while a lack of miR-146a/b leads to attenuated type 2 cell responses in mouse models of allergic airway inflammation and RV-induced exacerbation of allergic airway inflammation. Furthermore, our data indicate that the application of CPP-miR-146a nanocomplexes has therapeutic potential for targeting airway inflammation.

Spotlight on microRNAs in allergy and asthma

In past 10 years, microRNAs (miRNAs) have gained scientific attention due to their importance in the pathophysiology of allergic diseases and their potential as biomarkers in liquid biopsies. They act as master post‐transcriptional regulators that control most cellular processes. As one miRNA can target several mRNAs, often within the same pathway, dysregulated expression of miRNAs may alter particular cellular responses and contribute, or lead, to the development of various diseases. In this review, we give an overview of the current research on miRNAs in allergic diseases, including atopic dermatitis, allergic rhinitis, and asthma. Specifically, we discuss how individual miRNAs function in the regulation of immune responses in epithelial cells and specialized immune cells in response to different environmental factors and respiratory viruses. In addition, we review insights obtained from experiments with murine models of allergic airway and skin inflammation and offer an overview of studies focusing on miRNA discovery using profiling techniques and bioinformatic modeling of the network effect of multiple miRNAs. In conclusion, we highlight the importance of research into miRNA function in allergy and asthma to improve our knowledge of the molecular mechanisms involved in the pathogenesis of this heterogeneous group of diseases.

Expression analysis of circulating miR-146a and miR-155 as novel biomarkers related to effective immune responses in human cystic echinococcosis

Cystic echinococcosis, an important zoonotic disease, is caused by Echinococcus granulosus. MicroRNAs are a small group of single-stranded noncoding RNAs, which play an effective role in biological processes. This study aimed at comparing the expression levels of miR-146a and miR-155 in the plasma of patients with hydatidosis and healthy individuals. A group of 20 patients with hydatid cyst formed a study group and 20 healthy individuals with no known chronic diseases formed a control group. Plasma samples were collected from hydatidosis patients as well as sex- and age-matched healthy volunteers. After that, RNA extraction and cDNA synthesis were done and the expression levels of miR-146a and miR-155 were determined by quantitative real-time polymerase chain reaction (PCR) for both groups. The results indicated that the level of miR-146a increased in all patients with hydatidosis compared to the control group. Also, the level of miR-155 increased in all hydatidosis patients, but no correlation was observed in the level of miR-155 between the two groups. The results also revealed that miR-146a and miR-155 upregulation in the plasma leads to the development of novel biomarkers for echinococcosis. One of the reasons for the increase of miRNAs in hydatidosis may be their role in modulating the immune system. These miRNAs are likely to be considered as one of the most important biomarkers in determining the severity of hydatidosis.

MicroRNA155 Plays a Critical Role in the Pathogenesis of Cutaneous Leishmania major Infection by Promoting a Th2 Response and Attenuating Dendritic Cell Activity

Interferon (IFN)-γ is indispensable in the resolution of cutaneous leishmaniasis (CL), while the Th2 cytokines IL-4, IL-10, and IL-13 mediate susceptibility. A recent study found that miR155, which promotes CD4⁺ Th1 response and IFN-γ production, is dispensable in the control of Leishmania donovani infection. Here, the role of miR155 in CL caused by L. major was investigated using miR155-deficient (miR155^-/-) mice. Infection was controlled significantly quicker in the miR155^-/- mice than in their wild-type (WT) counterparts, indicating that miR155 contributes to the pathogenesis of CL. Faster resolution of infection in miR155^-/- mice was associated with increased levels of Th1-associated IL-12 and IFN-γ and reduced production of Th2- associated IL-4, IL-10, and IL-13. Concentrations of IFN-γ⁺CD8⁺ T cells and natural killer cells in draining lymph nodes were significantly higher in the L. major-infected miR155^-/- mice than in the infected WT mice, as indicated by flow-cytometry. After in vitro IFN-γ stimulation, nitric oxide and IL-12 production were increased, IL-10 production was decreased, and parasite clearance was enhanced in L. major-infected miR155^-/- DCs compared to those in WT DCs. Furthermore, IFN-γ production from activated miR155^-/- T cells was significantly enhanced in L. major-infected miR155^-/- DCs. Together, these findings demonstrate that miR155 promotes susceptibility to CL caused by L. major by promoting Th2 response and inhibiting DC function.

Inhibition of miR-99a-5p prevents allergen-driven airway exacerbations without compromising type-2 memory responses in the intestine following helminth infection

Acute exacerbations (AE) of asthma, remain one of the biggest concerns for patients living with asthma. As such, identifying the causes, the molecular mechanisms involved and new therapeutic interventions to prevent AE is a high priority. Immunity to intestinal helminths involves the reactivation of type-2 immune responses leading to smooth muscle contraction and mucus hypersecretion-physiological processes very similar to acute exacerbations in the airways following allergen exposure. In this study, we employed a murine model of intestinal helminth infection, using Heligmosomoides polygyrus, to identify miRNAs during active expulsion, as a system for the identification of miRNAs that may contribute to AE in the airways. Concomitant with type-2 immunity and expulsion of H. polygyrus, we identified miR-99a-5p, miR-148a-3p and miR-155-5p that were differentially regulated. Systemic inhibition of these miRNAs, alone or in combination, had minimal impact on expulsion of H. polygyrus, but inhibition of miR-99a-5p or miR-155-5p significantly reduced house dust mite (HDM)-driven acute inflammation, modelling human acute exacerbations. Immunological, pathological and transcriptional analysis identified that miR-155-5p or miR-99a-5p contribute significantly to HDM-driven AE and that transient inhibition of these miRNAs may provide relief from allergen-driven AE, without compromising anti-helminth immunity in the gut.

Lysolipids in Vascular Development, Biology, and Disease

Membrane phospholipid metabolism forms lysophospholipids, which possess unique biochemical and biophysical properties that influence membrane structure and dynamics. However, lysophospholipids also function as ligands for G-protein-coupled receptors that influence embryonic development, postnatal physiology, and disease. The 2 most well-studied species-lysophosphatidic acid and S1P (sphingosine 1-phosphate)-are particularly relevant to vascular development, physiology, and cardiovascular diseases. This review summarizes the role of lysophosphatidic acid and S1P in vascular developmental processes, endothelial cell biology, and their roles in cardiovascular disease processes. In addition, we also point out the apparent connections between lysophospholipid biology and the Wnt (int/wingless family) pathway, an evolutionarily conserved fundamental developmental signaling system. The discovery that components of the lysophospholipid signaling system are key genetic determinants of cardiovascular disease has warranted current and future research in this field. As pharmacological approaches to modulate lysophospholipid signaling have entered the clinical sphere, new findings in this field promise to influence novel therapeutic strategies in cardiovascular diseases.

Innate lymphoid cells in isocyanate-induced asthma: role of microRNA-155

BACKGROUND

Occupational asthma, induced by workplace exposures to low molecular weight agents such as toluene 2,4-diisocyanate (TDI), causes a significant burden to patients and society. Little is known about innate lymphoid cells (ILCs) in TDI-induced asthma. A critical regulator of ILC function is microRNA-155, a microRNA associated with asthma.

OBJECTIVE

To determine whether TDI exposure modifies the number of ILCs in the lung and whether microRNA-155 contributes to TDI-induced airway inflammation and hyperresponsiveness.

METHODS

C57BL/6 wild-type and microRNA-155 knockout mice were sensitised and challenged with TDI or vehicle. Intracellular cytokine expression in ILCs and T-cells was evaluated in bronchoalveolar lavage (BAL) fluid using flow cytometry. Peribronchial eosinophilia and goblet cells were evaluated on lung tissue, and airway hyperresponsiveness was measured using the forced oscillation technique. Putative type 2 ILCs (ILC2) were identified in bronchial biopsies of subjects with TDI-induced occupational asthma using immunohistochemistry. Human bronchial epithelial cells were exposed to TDI or vehicle.

RESULTS

TDI-exposed mice had higher numbers of airway goblet cells, BAL eosinophils, CD4⁺ T-cells and ILCs, with a predominant type 2 response, and tended to have airway hyperresponsiveness. In TDI-exposed microRNA-155 knockout mice, inflammation and airway hyperresponsiveness were attenuated. TDI exposure induced IL-33 expression in human bronchial epithelial cells and in murine lungs, which was microRNA-155 dependent in mice. GATA3⁺CD3^- cells, presumably ILC2, were present in bronchial biopsies.

CONCLUSION

TDI exposure is associated with increased numbers of ILCs. The proinflammatory microRNA-155 is crucial in a murine model of TDI asthma, suggesting its involvement in the pathogenesis of occupational asthma due to low molecular weight agents.

Oxysophocarpine protects airway epithelial cells against inflammation and apoptosis by inhibiting miR-155 expression

Oxysophocarpine (OSC) has been documented for anti-inflammatory activity. However, the mechanisms of OSC in anti-inflammation are unclear. Aim: To investigate the protective effects of OSC on inflammation and apoptosis induced by lipopolysaccharide in NCI-H292 and human primary airway epithelial cells. Materials & methods: MTT and Annexin V-FITC/PI staining were used to detect cells viability. Inflammatory responses were determined by ELISA. The quantitative real-time PCR (qRT-PCR) and western blot were used to detect mRNA/miRNA and protein expressions respectively. Co-immunoprecipitation was investigated for protein interactions. Results & conclusion: miR-155 mimics significantly induced cell apoptosis, inflammatory responses and MAPK and NF-κB pathways. NDFIP1 was identified as the target of miR-155. OSC protected cells against apoptosis and inflammatory responses and compromised miR-155 activity by attenuating MAPK and NF-κB pathways.

MicroRNAs in chronic airway diseases: Clinical correlation and translational applications

MicroRNAs (miRNAs) are short single-stranded RNAs that have pivotal roles in disease pathophysiology through transcriptional and translational modulation of important genes. It has been implicated in the development of many diseases, such as stroke, cardiovascular conditions, cancers and inflammatory airway diseases. There is recent evidence that miRNAs play important roles in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD), and could help to distinguish between T2-low (non-eosinophilic, steroid-insensitive) versus T2-high (eosinophilic, steroid-sensitive) disease endotypes. As these are the two most prevalent chronic respiratory diseases globally, with rising disease burden, miRNA research might lead to the development of new diagnostic and therapeutic targets. Research involving miRNAs in airway disease is challenging because: (i) asthma and COPD are heterogeneous inflammatory airway diseases; there are overlapping but distinct inter- and intra-disease differences in the immunological pathophysiology, (ii) there exists more than 2000 known miRNAs and a single miRNA can regulate multiple targets, (iii) differential effects of miRNAs could be present in different cellular subtypes and tissues, and (iv) dysregulated miRNA expression might be a direct consequence of an indirect effect of airway disease onset or progression. As miRNAs are actively secreted in fluids and remain relatively stable, they have the potential for biomarker development and therapeutic targets. In this review, we summarize the preclinical data on potential miRNA biomarkers that mediate different pathophysiological mechanisms in airway disease. We discuss the framework for biomarker development using miRNA and highlight the need for careful patient characterization and endotyping in the screening and validation cohorts, profiling both airway and blood samples to determine the biological fluids of choice in different disease states or severity, and adopting an untargeted approach. Collaboration between the various stakeholders - pharmaceutical companies, laboratory professionals and clinician-scientists is crucial to reduce the difficulties and cost required to bring miRNA research into the translational stage for airway diseases.

Emerging role of extracellular vesicles in the respiratory system

Extracellular vesicles (EVs) present numerous biomedical ways of studying disease and pathology. They function as protective packaging for the delivery of controlled concentrations of miRNAs and effector molecules, including cytokines, chemokines, genetic material, and small signaling molecules. Previous studies of EVs have yielded valuable insights into pathways of intercellular communication that affect a variety of biological processes and disease responses. The roles of EVs, specifically microRNA-containing EVs (EV-miRNAs), in either mitigating or exacerbating pulmonary disease symptoms are numerous and show promise in helping us understand pulmonary disease pathology. Because of their well-documented involvement in pulmonary diseases, EVs show promise both as possible diagnostic biomarkers and as therapeutic agents. This review surveys the physiological functions of EVs in the respiratory system and outlines the pulmonary disease states in which EVs are involved in intercellular crosstalk. This review also discusses the potential clinical applications of EV-miRNAs in pulmonary diseases.

Studies of tiny membrane-bound sacs called extracellular vesicles (EVs), which bud from cells naturally but are also implicated in disease, offer insights into respiratory health and disease, and could be used to deliver therapies into respiratory system cells. Joshua Holtzman at Oberlin College, Ohio, USA, and Heedoo Lee at Changwon National University in South Korea review current understanding of the role of EVs in the respiratory system and their potential uses in treatment. Researchers are discovering how EVs deliver signaling molecules to promote respiratory health, and how they can be involved in cancer, autoimmunity, asthma and other diseases. Early trials using EVs to deliver conventional drugs, and small RNA molecules that can control gene activity suggest great potential for treating a range of serious respiratory conditions. Analysis of EVs may also assist in diagnosis.

Airway mir-155 responses are associated with TH1 cytokine polarization in young children with viral respiratory infections

BACKGROUND

MicroRNAs (miRs) control gene expression and the development of the immune system and antiviral responses. MiR-155 is an evolutionarily-conserved molecule consistently induced during viral infections in different cell systems. Notably, there is still an unresolved paradox for the role of miR-155 during viral respiratory infections. Despite being essential for host antiviral TH1 immunity, miR-155 may also contribute to respiratory disease by enhancing allergic TH2 responses and NFkB-mediated inflammation. The central goal of this study was to define how airway miR-155 production is related to TH1, TH2, and pro-inflammatory cytokine responses during naturally occurring viral respiratory infections in young children.

METHODS

Normalized nasal airway levels of miR-155 and nasal protein levels of IFN-γ, TNF-α, IL-1β, IL-13, IL-4 were quantified in young children (≤2 years) hospitalized with viral respiratory infections and uninfected controls. These data were linked to individual characteristics and respiratory disease parameters.

RESULTS

A total of 151 subjects were included. Increased miR-155 levels were observed in nasal samples from patients with rhinovirus, RSV and all respiratory viruses analyzed. High miR-155 levels were strongly associated with high IFN-γ production, increased airway TH1 cytokine polarization (IFN-γ/IL-4 ratios) and increased pro-inflammatory responses. High airway miR-155 levels were linked to decreased respiratory disease severity in individuals with high airway TH1 antiviral responses.

CONCLUSIONS

The airway secretion of miR-155 during viral respiratory infections in young children is associated with enhanced antiviral immunity (TH1 polarization). Further studies are needed to define additional physiological roles of miR-155 in the respiratory tract of human infants and young children during health and disease.

Depletion of microRNA-451 in response to allergen exposure accentuates asthmatic inflammation by regulating Sirtuin2

The incidence of asthma has increased from 5.5% to near 8% of the population, which is a major health concern. The hallmarks of asthma include eosinophilic airway inflammation that is associated with chronic airway remodeling. Allergic airway inflammation is characterized by a complex interplay of resident and inflammatory cells. MicroRNAs (miRNAs) are small noncoding RNAs that function as posttranscriptional modulators of gene expression. However, the role of miRNAs, specifically miR-451, in the regulation of allergic airway inflammation is unexplored. Our previous findings showed that oxidant stress regulates miR-451 gene expression in macrophages during an inflammatory process. In this paper, we examined the role of miR-451 in regulating macrophage phenotype using an experimental poly-allergenic murine model of allergic airway inflammation. We found that miR-451 contributes to the allergic induction of CCL17 in the lung and plays a key role in proasthmatic macrophage activation. Remarkably, administration of a Sirtuin 2 (Sirt2) inhibitor diminished alternate macrophage activation and markedly abrogated triple-allergen [dust mite, ragweed, Aspergillus fumigatus (DRA)]-induced lung inflammation. These data demonstrate a role for miR-451 in modulating allergic inflammation by influencing allergen-mediated macrophages phenotype.

DsRNA induction of microRNA-155 disrupt tight junction barrier by modulating claudins

Background

The impaired barrier function of the airway epithelium due to RNA virus infection is closely related to the development and exacerbation of allergic airway inflammation.

Objective

In this study, we investigated the roles of microRNAs on the mechanisms of double-stranded RNA (dsRNA)-induced epithelial barrier dysfunction.

Methods

16HBE14o- human bronchial epithelial cells were grown to confluence on Transwell inserts and exposed to poly-I:C. We studied epithelial barrier function by measuring transepithelial electrical resistance and paracellular flux of fluorescent markers and structure of tight junctions by immunofluorescence microscopy.

Results

Poly-I:C treated 16HBE14o- cells increased paracellular permeability. Knockdown of Toll-like receptor 3 and TRIF abrogated these effects. The expression of microRNA-155 (miR-155) was increased by poly-I:C in dose-dependent manner. Transfection of mir155 mimics into 16HBE14o- cells increased permeability and inhibited tight junction formation. Transfection of miR-155 inhibitor suppressed poly-I:C-induced barrier disruption. Poly-I:C treatment significantly decreased the expression of claudin members—claudin-1, -3, -4, -5, -9, -11, -16, -18 and -19. Transfection of miR-155 mimics showed similar changing expression pattern of claudin members with those of poly-I:C treatment.

Conclusion

These results suggest that RNA virus infection can impair the epithelial barrier disruption mechanism by down-regulation of claudin members through the induction of miR-155.

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

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

CD29 identifies IFN-γ-producing human CD8+ T cells with an increased cytotoxic potential

Cytotoxic CD8+ T cells can effectively kill target cells by producing cytokines, chemokines, and granzymes. Expression of these effector molecules is however highly divergent, and tools that identify and preselect CD8+ T cells with a cytotoxic expression profile are lacking. Human CD8+ T cells can be divided into IFN-γ- and IL-2-producing cells. Unbiased transcriptomics and proteomics analysis on cytokine-producing fixed CD8+ T cells revealed that IL-2+ cells produce helper cytokines, and that IFN-γ+ cells produce cytotoxic molecules. IFN-γ+ T cells expressed the surface marker CD29 already prior to stimulation. CD29 also marked T cells with cytotoxic gene expression from different tissues in single-cell RNA-sequencing data. Notably, CD29+ T cells maintained the cytotoxic phenotype during cell culture, suggesting a stable phenotype. Preselecting CD29-expressing MART1 TCR-engineered T cells potentiated the killing of target cells. We therefore propose that CD29 expression can help evaluate and select for potent therapeutic T cell products.

ncRNAs in Type-2 Immunity

Immunological diseases, including asthma, autoimmunity and immunodeficiencies, affect a growing percentage of the population with significant unmet medical needs. As we slowly untangle and better appreciate these complex genetic and environment-influenced diseases, new therapeutically targetable pathways are emerging. Non-coding RNA species, which regulate epigenetic, transcriptional and translational responses are critical regulators of immune cell development, differentiation and effector function, and may represent one such new class of therapeutic targets. In this review we focus on type-2 immune responses, orchestrated by T_H2 cell-derived cytokines, IL-4, IL-5 and IL-13, which stimulate a variety of immune and tissue responses- commonly referred to as type-2 immunity. Evolved to protect us from parasitic helminths, type-2 immune responses are observed in individuals with allergic diseases, including Asthma, atopic dermatitis and food allergy. A growing number of studies have identified the involvement of various RNA species, including microRNAs (miRNA) and long non-coding (lncRNA), in type-2 immune responses and in both clinical and pre-clinical disease settings. We highlight these recent findings, identify gaps in our understanding and provide a perspective on how our current understanding can be harnessed for novel treat opportunities to treat type-2 immune-mediated diseases.

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.

Systems biology and big data in asthma and allergy: recent discoveries and emerging challenges

Asthma is a common condition caused by immune and respiratory dysfunction, and it is often linked to allergy. A systems perspective may prove helpful in unravelling the complexity of asthma and allergy. Our aim is to give an overview of systems biology approaches used in allergy and asthma research. Specifically, we describe recent "omic"-level findings, and examine how these findings have been systematically integrated to generate further insight.Current research suggests that allergy is driven by genetic and epigenetic factors, in concert with environmental factors such as microbiome and diet, leading to early-life disturbance in immunological development and disruption of balance within key immuno-inflammatory pathways. Variation in inherited susceptibility and exposures causes heterogeneity in manifestations of asthma and other allergic diseases. Machine learning approaches are being used to explore this heterogeneity, and to probe the pathophysiological patterns or "endotypes" that correlate with subphenotypes of asthma and allergy. Mathematical models are being built based on genomic, transcriptomic and proteomic data to predict or discriminate disease phenotypes, and to describe the biomolecular networks behind asthma.The use of systems biology in allergy and asthma research is rapidly growing, and has so far yielded fruitful results. However, the scale and multidisciplinary nature of this research means that it is accompanied by new challenges. Ultimately, it is hoped that systems medicine, with its integration of omics data into clinical practice, can pave the way to more precise, personalised and effective management of asthma.

To TRIM the Immunity: From Innate to Adaptive Immunity

The tripartite motif (TRIM) proteins have been intensively studied as essential modulators in various biological processes, especially in regulating a wide range of signaling pathways involved in immune responses. Most TRIM proteins have E3 ubiquitin ligase activity, mediating polyubiquitination of target proteins. Emerging evidence demonstrates that TRIM proteins play important roles in innate immunity by regulating pattern recognition receptors, vital adaptor proteins, kinases, and transcription factors in innate immune signaling pathways. Additionally, the critical roles of TRIM proteins in adaptive immunity, especially in T cell development and activation, are increasingly appreciated. In this review, we aim to summarize the studies on TRIMs in both innate and adaptive immunity, focusing on their E3 ubiquitin ligase functions in pattern recognition receptor signaling pathways and T cell functions, shedding light on the developing new strategies for modulating innate and adaptive immune responses against invading pathogens and avoiding autoimmunity.

Molecular techniques for respiratory diseases: MicroRNA and extracellular vesicles

miRNA are a class of evolutionarily conserved non-coding 19- to 22-nt regulatory RNA. They affect various cellular functions through modulating the transcriptional and post-transcriptional levels of their target mRNA by changing the stability of protein-coding transcripts or attenuating protein translation. miRNA were discovered in the early 1990s, and they have been the focus of new research in both basic and clinical medical sciences. Today, it has become clear that specific miRNA are linked to the pathogenesis of respiratory diseases, as well as cancer and cardiovascular disease. In addition, EV, including exosomes, which are small membrane-bound vesicles secreted by cells, were found to contain various functional miRNA that can be used for diagnostic and therapeutic purposes. As body fluids, such as blood and respiratory secretions, are major miRNA sources in the body, EV carrying extracellular miRNA are considered potentially useful for the diagnosis and assessment of pathological conditions, as well as the treatment of respiratory or other diseases. Although research in the field of lung cancer is actively progressing, studies in other respiratory fields have emerged recently as well. In this review, we provide an update in the topics of miRNA and EV focused on airway inflammatory diseases, such as asthma and COPD, and explore their potential for clinical applications on respiratory diseases.

Helminth-induced Th2 cell dysfunction is distinct from exhaustion and is maintained in the absence of antigen

T cell-intrinsic regulation, such as anergy, adaptive tolerance and exhaustion, is central to immune regulation. In contrast to Type 1 and Type 17 settings, knowledge of the intrinsic fate and function of Th2 cells in chronic Type 2 immune responses is lacking. We previously showed that Th2 cells develop a PD-1/PD-L2-dependent intrinsically hypo-responsive phenotype during infection with the filarial nematode Litomosoides sigmodontis, denoted by impaired functionality and parasite killing. This study aimed to elucidate the transcriptional changes underlying Th2 cell-intrinsic hypo-responsiveness, and whether it represents a unique and stable state of Th2 cell differentiation. We demonstrated that intrinsically hypo-responsive Th2 cells isolated from L. sigmodontis infected mice stably retained their dysfunctional Th2 phenotype upon transfer to naïve recipients, and had a divergent transcriptional profile to classical Th2 cells isolated prior to hypo-responsiveness and from mice exposed to acute Type 2 stimuli. Hypo-responsive Th2 cells displayed a distinct transcriptional profile to exhausted CD4+ T cells, but upregulated Blimp-1 and the anergy/regulatory-associated transcription factors Egr2 and c-Maf, and shared characteristics with tolerised T cells. Hypo-responsive Th2 cells increased mRNA expression of the soluble regulatory factors Fgl2, Cd38, Spp1, Areg, Metrnl, Lgals3, and Csf1, and a subset developed a T-bet+IFN-γ+ Th2/Th1 hybrid phenotype, indicating that they were not functionally inert. Contrasting with their lost ability to produce Th2 cytokines, hypo-responsive Th2 cells gained IL-21 production and IL-21R blockade enhanced resistance to L. sigmodontis. IL-21R blockade also increased the proportion of CD19+PNA+ germinal centre B cells and serum levels of parasite specific IgG1. This indicates a novel regulatory role for IL-21 during filarial infection, both in controlling protection and B cell responses. Thus, Th2 cell-intrinsic hypo-responsiveness is a distinct and stable state of Th2 cell differentiation associated with a switch from a classically active IL-4+IL-5+ Th2 phenotype, to a non-classical dysfunctional and potentially regulatory IL-21+Egr2+c-Maf+Blimp-1+IL-4loIL-5loT-bet+IFN-γ+ Th2 phenotype. This divergence towards alternate Th2 phenotypes during chronicity has broad implications for the outcomes and treatment of chronic Type 2-related infections and diseases.

Maternal Obesity in Mice Exacerbates the Allergic Inflammatory Response in the Airways of Male Offspring

It was previously demonstrated that non-allergen-sensitized rodents born to mothers exposed to a high-fat diet (HFD) spontaneously develop lower respiratory compliance and higher respiratory resistance. In the present study, we sought to determine if mice born to mothers consuming HFD would exhibit changes in inflammatory response and lung remodeling when subjected to ovalbumin (OVA) sensitization/challenge in adult life. Mice born to dams consuming either HFD or standard chow had increased bronchoalveolar lavage (BAL) levels of IL-1β, IL-4, IL-5, IL-10, IL-13, TNF-α and TGF-β1 after challenge with OVA. IL-4, IL-13, TNF-α and TGF-β1 levels were further increased in the offspring of HFD-fed mothers. Mice born to obese dams also had exacerbated values of leukocyte infiltration in lung parenchyma, eosinophil and neutrophil counts in BAL, mucus overproduction and collagen deposition. The programming induced by maternal obesity was accompanied by increased expression of miR-155 in peripheral-blood mononuclear cells and reduced miR-133b in trachea and lung tissue in adult life. Altogether, the present data support the unprecedented notion that the progeny of obese mice display exacerbated responses to sensitization/challenge with OVA, leading to the intensification of the morphological changes of lung remodeling. Such changes are likely to result from long-lasting changes in miR-155 and miR-133b expression.

Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration

Background

The role of miRNAs in the pathogenesis and determining the phenotypes of asthma is not fully elucidated. miR-146a has been previously shown to suppress inflammatory responses in different cells. In this study, we investigated the functions of miR-146a in human bronchial epithelial cells (HBECs) in association with neutrophilic, eosinophilic, and paucigranulocytic phenotypes of asthma.

Methods

Bronchial brushing specimens and brochial mucosal biopsy samples were collected from adult patients with asthma and from age- and gender-matched non-asthmatic individuals. The expression of miR-146a in bronchial brushing specimens, bronchial biopsy tissue sections or cultured primary bronchial epithelial cells was analyzed by RT-qPCR or by in situ hybridization. The expression of direct and indirect miR-146a target genes was determined by RT-qPCR or ELISA. The migration of neutrophils was studied by neutrophil chemotaxis assay and flow cytometry. For statistical analysis, unpaired two-way Student’s t test, one-way ANOVA or linear regression analysis were used.

Results

Reduced expression of miR-146a was found in bronchial brushing specimens from asthma patients as compared to non-asthmatics and irrespective of the phenotype of asthma. In the same samples, the neutrophil attracting chemokines IL-8 and CXCL1 showed increased expression in patients with neutrophilic asthma and increased IL-33 expression was found in patients with eosinophilic asthma. Linear regression analysis revealed a significant negative association between the expression of miR-146a in bronchial brushings and neutrophil cell counts in bronchoalveolar lavage fluid of patients with asthma. In bronchial biopsy specimens, the level of miR-146a was highest in the epithelium as determined with in situ hybridization. In primary conventional HBEC culture, the expression of miR-146a was induced in response to the stimulation with IL-17A, TNF-α, and IL-4. The mRNA expression and secretion of IL-8 and CXCL1 was inhibited in both stimulated and unstimulated HBECs transfected with miR-146a mimics. Supernatants from HBECs transfected with miR-146a had reduced capability of supporting neutrophil migration in neutrophil chemotaxis assay.

Conclusion

Our results suggest that decreased level of miR-146a in HBECs from patients with asthma may contribute to the development of neutrophilic phenotype of asthma.

MicroRNA-155-5p is a key regulator of allergic inflammation, modulating the epithelial barrier by targeting PKIα

Recent studies have demonstrated that microRNA-155-5p (miR-155-5p) plays an essential role in the regulation of allergen-induced inflammation and is overexpressed in the skin of patients with atopic dermatitis (AD), although the mechanism is unknown. In this study, silencing miR-155-5p attenuated the thickening of the epidermis in AD model and reduced the infiltration of inflammatory cells and the secretion of Th2 cytokines. Protein kinase inhibitor α (PKIα) was identified as a direct target of miR-155-5p and correlated negatively with miR-155-5p in our AD model. Fluorescence in situ hybridization showed that miR-155-5p-expressing cells were predominantly present in the epidermis. When epithelial cells were transfected with an miR-155-5p inhibitor, the expression of PKIα, occludin, and CLDN16 increased and that of TSLP decreased significantly, whereas the overexpression of miR-155-5p resulted in the opposite changes. The increased expression of PKIα and tight junction (TJ) proteins, with reduced TSLP and IL-33, was also detected in miR-155-5p-blocked mice, in both the initial and elicitation stages of AD. The expression of TJ proteins also decreased when cells were transfected with PKIα siRNA. TJ proteins increased and TSLP and IL-33 decreased significantly after the overexpression of PKIα. Our data provide the first evidence that miR-155-5p is critical for the allergic inflammation in a mouse model of AD by directly regulating PKIα and thus epithelial TJ expression. These findings suggest new therapeutic strategies that target miR-155-5p in patients with allergic disorders.

Isorhynchophylline exerts anti-asthma effects in mice by inhibiting the proliferation of airway smooth muscle cells: The involvement of miR-200a-mediated FOXC1/NF-κB pathway

Hyperplasia of airway smooth muscle cells (ASMCs) is key to the progression of asthma. Isorhynchophylline (IRN) derived from Uncaria rhynchophylla can inhibit the proliferation of AMSCs. The major purpose of the current study was to assess the effect of IRN on the asthma symptoms was assessed both in vitro and in vivo, and the associated mechanism of the effect was also explored by focusing on the function of miR-200a. Asthma model was induced using ovalbumin (OVA) method and AMSC hyperplasia model was induced using TGF-β1. The effect of IRN on allergic asthma mice and the effect of IRN on the proliferation of ASMCs were investigated as well, and the changes in miR-200a level and FOXC1/NF-κB pathway were detected. The administration of IRN attenuated the eosinophils recruitment in BALF, reduced collagen deposition in lung tissues, and suppressed production of IgE and pro-inflammation cytokines. IRN also inhibited the proliferation and induced the apoptosis of ASMCs. Moreover, the administration of IRN increased the level of miR-200a while inhibited the activation of FOXC1/NF-κB pathway. However, after the inhibition of miR-200a level, the function of IRN on ASMCs was impaired. Collectively, it was demonstrated that the effect of IRN on asthma relied on the up-regulation of miR-200a, which then deactivated FOXC1/NF-κB pathway.

A translational perspective on epigenetics in allergic diseases

The analysis of epigenetic modifications in allergic diseases has recently attracted substantial interest because epigenetic modifications can mediate the effects of the environment on the development of or protection from allergic diseases. Furthermore, recent research has provided evidence for an altered epigenomic landscape in disease-relevant cell populations. Although still in the early phase, epigenetic modifications, particularly DNA methylation and microRNAs, might have potential for assisting in the stratification of patients for treatment and complement or replace in the future biochemical or clinical tests. The first epigenetic biomarkers correlating with the successful outcome of immunotherapy have been reported, and with personalized treatment options being rolled out, epigenetic modifications might well play a role in monitoring or even predicting the response to tailored therapy. However, further studies in larger cohorts with well-defined phenotypes in specific cell populations need to be performed before their implementation. Furthermore, the epigenome provides an interesting target for therapeutic intervention, with microRNA mimics, inhibitors, and antisense oligonucleotides being evaluated in clinical trials in patients with other diseases. Selection or engineering of populations of extracellular vesicles and epigenetic editing represent novel tools for modulation of the cellular phenotype and responses, although further technological improvements are required. Moreover, interactions between the host epigenome and the microbiome are increasingly recognized, and interventions of the microbiome could contribute to modulation of the epigenome with a potential effect on the overall goal of prevention of allergic diseases.

ILC2 Activation by Protozoan Commensal Microbes

Group 2 innate lymphoid cells (ILC2s) are a member of the ILC family and are involved in protective and pathogenic type 2 responses. Recent research has highlighted their involvement in modulating tissue and immune homeostasis during health and disease and has uncovered critical signaling circuits. While interactions of ILC2s with the bacterial microbiome are rather sparse, other microbial members of our microbiome, including helminths and protozoans, reveal new and exciting mechanisms of tissue regulation by ILC2s. Here we summarize the current field on ILC2 activation by the tissue and immune environment and highlight particularly new intriguing pathways of ILC2 regulation by protozoan commensals in the intestinal tract.

Multiple roles of microRNA-146a in immune responses and hepatocellular carcinoma

MicroRNAs (miRNAs/miRs), consisting of ~22 nucleotides of single-stranded RNA, participate in post-transcriptional gene regulation by binding to the 3′-untranslated region (UTR) of mRNAs, repressing their translation and promoting their degradation. Studies have shown that certain miRNAs play a key role in the control of various cellular activities, such as inhibiting inflammation, modulating cell differentiation and suppressing cancer growth. The role of miR-146a in the immune response and in the pathogenesis of hepatocellular carcinoma (HCC) has also been investigated. Although some studies have shown that increased miR-146a levels are associated with HCC, others have revealed that miR-146a suppresses cancer cell proliferation, invasion and metastasis. Toll-like receptor 4 (TLR4) signaling has an important role in regulating innate and adaptive immune responses. In addition, TLR4 is functionally expressed in HCC cells and promotes HCC cell proliferation, which can be regulated by miR-146a. The present review focuses on the recent progress in analyzing the multiple roles of miR-146a in mediating the TLR4 pathway and adaptive immune response. Finally, the function of miR-146a in the pathogenesis of HCC is also discussed.

Immune promotive effect of bioactive peptides may be mediated by regulating the expression of SOCS1/miR-155

The present study was designed to evaluate the effect of bioactive hepatic peptide (BHP) on the immune function of mice and to examine the mechanism mediated by the related factors cytokine suppressor of cytokine signaling 1 (SOCS1) and microRNA (miR)-155. The mice were divided into eight groups, including a normal mouse group, normal peptide groups (low-dose, mid-dose and high-dose), an immunosuppressed group, and immunosuppressed with peptide groups (low-dose, mid-dose and high-dose). The proliferative ability of splenic lymphocytes was determined in vitro using a Cell Counting kit-8 assay. Wright's staining was used to assess the phagocytic function of macrophages. Histological changes in the spleen were evaluated by hematoxylin-eosin staining. The relevant factors SOCS1/miR-155 were assessed by immunohistochemistry and reverse transcription fluorescence-quantitative polymerase chain reaction analysis. The levels of the cytokines TGF-β1, IL-10 and IL-17A were determined by enzyme-linked immunosorbent assay. First, the organ index, percentage of lymphocytes, phagocytosis experiments and splenic lymphocyte proliferation test results revealed that the immunodeficient mouse model had been successfully established. Second, compared with the control mice, the normal peptide group mice exhibited increased spleen and thymus indices, percentages of lymphocyte subsets, macrophage phagocytosis percentages, phagocytic indices, splenic lymphocyte proliferation and expression of miR-155; however, the expression of SOCS1 was decreased in the normal peptide groups to varying extents. In addition, the expression of SOCS1 was upregulated, whereas that of miR-155 was downregulated in the immunosuppressed group. Compared with the mice in the immunosuppressed group, the mice in the immunosuppressed with peptide groups had increased spleen and thymus indices, percentages of lymphocyte subsets, macrophage phagocytosis percentages, phagocytic indices, splenic lymphocyte proliferation and expression of miR-155; however, the expression of SOCS1 was decreased in the immunosuppressed with peptide groups to varying extents. Following treatment with BHP, the secretion of TGF-β1 in the spleen of the normal mice and immunosuppressed mice was significantly decreased, and the secretion of IL-10 was significantly increased. No significant difference in the expression of IL-17A was observed among the groups. In summary, BHP improved the immune function of the normal mice and immunosuppressed mice. This data provides a scientific basis for the development of bioactive peptide health products.