MicroRNA-21 inhibition attenuates airway inflammation and remodelling by modulating the transforming growth factor β-Smad7 pathway

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

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

Milk-Derived Small Extracellular Vesicles Promote Osteogenic Differentiation and Inhibit Inflammation via microRNA-21

Chronic apical periodontitis (CAP) is a disease with characteristics of inflammation and bone loss. In this study, our objective was to examine the function of small extracellular vesicles (sEVs) obtained from milk in encouraging osteogenic differentiation and inhibiting inflammation by miR-21 in CAP. The expression of miR-21 was detected using qRT-PCR in human CAP samples. The impact of miR-21 on the process of osteogenic differentiation was investigated using CCK-8, qRT-PCR, immunofluorescence staining, and Western blot analysis. The evaluation of RAW 264.7 cell polarization and the assessment of inflammatory factor expression were conducted through qRT-PCR. The influence of sEVs on MC3T3-E1 cells and RAW 264.7 cells was examined, with a particular emphasis on the involvement of miR-21. In human CAP samples, a decrease in miR-21 expression was observed. MiR-21 increased the expression of osteogenesis-related genes and M2 polarization genes while decreasing the expression of M1 polarization genes and inflammatory cytokines. Treatment with milk-derived sEVs also promoted osteogenesis and M2 polarization while inhibiting M1 polarization and inflammation. Conversely, the addition of miR-21 inhibitors resulted in opposite effects. Our results indicated that sEVs derived from milk had a positive effect on bone formation and activation of anti-inflammatory (M2) macrophages and simultaneously reduced inflammation by regulating miR-21 in CAP.

Noncoding RNAs in asthmatic airway smooth muscle cells

Asthma is a complex and heterogeneous airway disease caused by genetic, environmental and epigenetic factors treated with hormones and biologics. Irreversible pathological changes to airway smooth muscle cells (ASMCs) such as hyperplasia and hypertrophy can occur in asthmatic patients. Determining the mechanisms responsible is vital for preventing such changes. In recent years, noncoding RNAs (ncRNAs), especially microRNAs, long noncoding RNAs and circular RNAs, have been found to be associated with abnormalities of the ASMCs. This review highlights recent ncRNA research into ASMC pathologies. We present a schematic that illustrates the role of ncRNAs in pathophysiological changes to ASMCs that may be useful in future research in diagnostic and treatment strategies for patients with asthma.

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.

Evaluation of asthma-chronic obstructive pulmonary disease overlap using a mouse model of pulmonary disease

BACKGROUND

Features of asthma and chronic obstructive pulmonary disease (COPD) can coexist in the same patient, in a condition termed asthma- chronic obstructive pulmonary disease overlap (ACO). ACO is heterogeneous condition exhibiting various combinations of asthma and COPD features. No clinically acceptable experimental model of ACO has been established. We aimed to establish an animal model of ACO.

METHODS

We generated two phenotypes of ACO by administering ovalbumin and porcine pancreatic elastase in combination, and papain. The proinflammatory cytokines and cell types in bronchoalveolar lavage fluid (BALF) were investigated, and lung function parameters were measured using the FlexiVent system.

RESULTS

Greater airway inflammation was observed in the asthma and both ACO models, and emphysema was found in the COPD and both ACO models. The proportion of eosinophils in BALF was elevated in the asthma and ACO-a model. Type 2 inflammatory cytokine levels were highest in the ACO-a model, and the neutrophil gelatinase-associated lipocalin level was elevated in the asthma and ACO-a model. Of lung function parameters, compliance was greater in the COPD and ACO-b model, in which elastance was lower than in the asthma model. Airway resistance increased with the methacholine concentration in the asthma and both ACO models, but not in the control or COPD model.

CONCLUSION

We established two murine models of ACO that exhibit features of asthma and COPD. We validated the clinical relevance of the ACO models based on changes in cytokine profiles and lung function. These models will be useful in further studies of the pathogenesis of, and therapeutic targets for ACO.

MicroRNA-21-5p promotes mucosal type 2 inflammation via regulating GLP1R/IL-33 signaling in chronic rhinosinusitis with nasal polyps

BACKGROUND

It has been known that chronic rhinosinusitis with nasal polyps (CRSwNP) is a type 2 inflammation-dominated disease; however, the reasons causing such type of mucosal inflammation in CRSwNP are not well elucidated.

OBJECTIVE

We sought to investigate the role of microRNA-21-5p (miR-21-5p) in regulating mucosal type 2 inflammation in CRSwNP.

METHODS

miR-21-5p expression was detected in nasal mucosa of patients with CRSwNP. Correlations between miR-21-5p and indicators of type 2 inflammation were further analyzed. miR-21 knockout mice were used to explore the role of miR-21-5p in a murine model of eosinophilic (E) CRSwNP. Target gene of miR-21-5p related to type 2 inflammation in CRSwNP was identified.

RESULTS

The upregulated miR-21-5p in the nasal mucosa of patients with CRSwNP, compared with control subjects, was expressed higher in patients with ECRSwNP than in patients with nonECRSwNP. miR-21-5p expression was positively correlated with mucosal eosinophil infiltrations and the expression of type 2 inflammatory cytokines. In the CRSwNP mice, miR-21 knockout significantly attenuated type 2 inflammation, as indicated by eosinophil infiltrations and expression of cytokines/chemokines in nasal mucosa and lavage fluid; moreover, genes associated with type 2 inflammation were extensively downregulated at the transcriptome level in miR-21 knockout mice. Glucagon-like peptide-1 receptor, which was negatively correlated with miR-21-5p expression in human nasal mucosa, was identified as the target of miR-21-5p. Overexpression of miR-21-5p induced IL-33 expression, whereas glucagon-like peptide-1 receptor agonist decreased IL-33 production in airway epithelial cells.

CONCLUSIONS

miR-21-5p aggravates type 2 inflammation in the nasal mucosa of patients with CRSwNP via targeting glucagon-like peptide-1 receptor/IL-33 signaling, which may be a potential therapeutic target for CRSwNP.

Recent miRNA Research in Asthma

PURPOSE OF REVIEW

The study of microRNA in asthma has revealed a vibrant new level of gene regulation underlying asthma pathology. Several miRNAs have been shown to be important in asthma, influencing various biological mechanisms which lead to asthma pathology and symptoms. In addition, miRNAs have been proposed as biomarkers of asthma affection status, asthma severity, and asthma treatment response. We review all recent asthma-miRNA work, while also presenting comprehensive tables of all miRNA results related to asthma.

RECENT FINDINGS

We here reviewed 63 recent studies published reporting asthma and miRNA research, and an additional 14 reviews of the same. We summarized the information for both adult and childhood asthma, as well as research on miRNAs in asthma-COPD overlap syndrome (ACOs), and virus-induced asthma exacerbations. We attempted to present a comprehensive collection of recently published asthma-associated miRNAs as well as tables of all published asthma-related miRNA results.