Combination of TLR agonist and miR146a mimics attenuates ovalbumin-induced asthma

circRNA/TLR interaction: key players in immune regulation and autoimmune diseases

Circular RNAs are a class of non-coding RNAs with covalently closed loops. They have been revealed to regulate immune responses by affecting gene expression. Although initially considered splicing byproducts, new studies have indicated their role in transcriptional and post-transcriptional control, especially with TLRs. TLRs start inflammatory signaling and let the innate immune system recognize PAMPs. circRNAs interact context-dependently with TLR pathways to influence immune homeostasis and inflammation in either pathogenic or protective roles. In autoimmune diseases, dysregulated circRNA expression can aggravate immune responses and damage tissue. CircRNAs can interact with RNA-binding proteins, function as molecular sponges for miRNAs, and change inflammatory pathways like the NF-κB signaling cascade, influencing immune responses. They control adaptive immunity, function of antigen-presenting cells, and cytokine generation. The stability and presence of circRNAs in many body fluids make them therapeutic targets and biomarkers for inflammatory and autoimmune diseases. The several immune control roles of circRNA-TLR interactions are discussed in this review, as well as their consequences for immunologically mediated disease diagnosis and treatment.

Regulation of B-cell function by miRNAs impacting Systemic lupus erythematosus progression

Systemic lupus erythematosus (SLE) is a complex autoimmune disease marked by abnormal B-cell proliferation and increased autoantibodies. miRNAs play a crucial role in regulating B-cell dysfunction and SLE pathology. miRNAs influence DNA methylation, B-cell activation, and gene expression, contributing to SLE pathogenesis. miRNAs impact B cells through key processes like proliferation, differentiation, tolerance, and apoptosis. miRNAs also exacerbate inflammation and immune responses by modulating Interleukin 4 (IL-4), IL-6, and interferon cytokines. Autophagy, a key degradation mechanism, is also regulated by specific miRNAs that impact SLE pathology. This article explores the role of multiple miRNAs in regulating B-cell development, proliferation, survival, and immune responses, influencing SLE pathogenesis. miRNAs like miR-23a, the miR-17 ∼ 92 family, and miR-125b/miR-221 affect B-cell development by regulating transcription factors, signaling pathways, and cell cycle genes. miRNAs such as miR-181a-5p and miR-23a-5p are differentially regulated across developmental stages, emphasizing their complex regulatory roles in B-cell biology. This article synthesizes miRNA-B cell interactions to offer new strategies and directions for SLE diagnosis and treatment.

Oral Delivery of miR146a Conjugated to Cerium Oxide Nanoparticles Improves an Established T Cell-Mediated Experimental Colitis in Mice

Background: Dysregulated inflammation and oxidative stress are strongly implicated in the pathogenesis of inflammatory bowel disease. We have developed a novel therapeutic that targets inflammation and oxidative stress. It is comprised of microRNA-146a (miR146a)-loaded cerium oxide nanoparticles (CNPs) (CNP-miR146a). We hypothesized that oral delivery of CNP-miR146a would reduce colonic inflammation in a mouse model of established, chronic, T cell-mediated colitis. Methods: The stability of CNP-miR146a and mucosal delivery was assessed in vitro with simulated gastrointestinal fluid and in vivo after oral gavage by quantitative real-time RT-PCR. The efficacy of orally administered CNP-miR146a was tested in mice with established colitis using the model of adoptive naïve T-cell transfer in recombinant activating gene 2 knockout (Rag2-/-) mice. Measured outcomes included histopathology; CD45+ immune cell infiltration; oxidative DNA damage (tissue 8-hydroxy-2'-deoxyguanosine; 8-OHdG); expression of IL-6 and TNF mRNA and protein, and flow cytometry analysis of lamina propria Th1 and Th17 cell populations. Results: miR146a expression remained stable in simulated gastric and intestinal conditions. miR146a expression increased in the intestines of mice six hours following oral gavage of CNP-miR146a. Oral delivery of CNP-miR146a in mice with colitis was associated with reduced inflammation and oxidative stress in the proximal and distal colons as evidenced by histopathology scoring, reduced immune cell infiltration, reduced IL-6 and TNF expression, and decreased populations of CD4+Tbet+IFNg+ Th1, CD4+RorgT+IL17+ Th17, as well as pathogenic double positive IFNg+IL17+ T cells. Conclusions: CNP-miR146a represents a novel orally available therapeutic with high potential to advance into clinical trials.

Integrating nontargeted metabolomics and RNA sequencing of dexamethasone-treated and untreated asthmatic mice reveals changes of amino acids and aminoacyl-tRNA in group 2 innate lymphoid cells

Bronchial asthma is the most common multifactorial and heterogeneous disease in childhood. The glucocorticoid dexamethasone is a classic treatment for asthma. Research indicates that group 2 innate lymphoid cells (ILC2s) are crucial to the pathogenesis of asthma. However, few studies have focused on ILC2s metabolism and transcription. This study aims to establish an ovalbumin (OVA)-induced asthma model and a dexamethasone-treated asthma model to explore the regulation of lung ILC2s at the genetic and metabolic levels during the progression and remission of asthma, utilizing single-cell metabolomics and transcriptomics approaches. The results showed that ILC2s regulated the metabolic pathways and transcriptional levels of amino acids (such as arginine, proline, and histidine) and linoleic acid, as well as the metabolic biomarkers of arginine, urocanic acid, and linoleic acid in asthma. Additionally, the cytokine pathways and NF-γB pathways have been altered at the genetic level. At the same time, we revealed that dexamethasone regulates ILC2s amino acid and aminoacyl tRNA metabolism, as well as related genes, thereby alleviating asthma symptoms. Furthermore, we identified the genes Eno3 and Tap1, which are significantly associated with asthma. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to verify the accuracy of the RNA sequencing results. This study, for the first time, revealed the mechanistic changes of ILC2s in the development and treatment of asthma using multiomics techniques, laying a foundation for targeted therapies in asthma.

Circulating miRNAs act as potential biomarkers for asthma

Background

Identification of new clinical markers contributes to a better understanding of the pathogenesis of asthma. Considering the crucial role of LIGHT in asthma, it may become a potential target for asthma. The aim of current study was to determine if circulating microRNAs (miRNAs) targeting LIGHT may be used as diagnostic biomarkers to distinguish asthma.

Methods

Blood serum from a cohort of 60 subjects, including 20 cases with mild asthma, 20 cases with moderate-to-severe asthma, and 20 healthy controls were included. Serum was analyzed for circulating miRNAs profiles through miRNAs microarray. Real Time PCR was conducted to verify the results of miRNA microarray. Correlations between circulating miRNAs targeting LIGHT and clinical characteristics were investigated.

Results

A total of 365 miRNAs were differentially expressed in asthma patients. Among them, miR-107 and miR-140-5p were found to target LIGHT, and varied in asthmatics. Additionally, miR-107 and miR-140-5p expressions were positively correlated with the absolute value of peripheral eosinophils. Finally, miR-140-5p and miR-107 were demonstrated to have good diagnostic efficacy for asthma (AUC= 0.8667 and 0.9400) with good sensitivity (0.8000 and 0.8667,respectively) and specificity (0.8667 and 0.867). Thus, circulating miRNAs expressed differentially between healthy control and asthma patients.

Conclusion

Plasma miR-140-5p and miR-107 can be used as diagnostic biomarkers to distinguish patients with asthma from healthy control, and may take part in asthma pathogenesis by negatively regulating LIGHT. Further research was needed to evaluate their roles as potential biomarkers in the diagnosis of asthma.

Exosomal microRNA/miRNA Dysregulation in Respiratory Diseases: From Mycoplasma-Induced Respiratory Disease to COVID-19 and Beyond

Respiratory diseases represent a significant economic and health burden worldwide, affecting millions of individuals each year in both human and animal populations. MicroRNAs (miRNAs) play crucial roles in gene expression regulation and are involved in various physiological and pathological processes. Exosomal miRNAs and cellular miRNAs have been identified as key regulators of several immune respiratory diseases, such as chronic respiratory diseases (CRD) caused by Mycoplasma gallisepticum (MG), Mycoplasma pneumoniae pneumonia (MMP) caused by the bacterium Mycoplasma pneumoniae, coronavirus disease 2019 (COVID-19), chronic obstructive pulmonary disease (COPD), asthma, and acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Consequently, miRNAs seem to have the potential to serve as diagnostic biomarkers and therapeutic targets in respiratory diseases. In this review, we summarize the current understanding of the functional roles of miRNAs in the above several respiratory diseases and discuss the potential use of miRNAs as stable diagnostic biomarkers and therapeutic targets for several immune respiratory diseases, focusing on the identification of differentially expressed miRNAs and their targeting of various signaling pathways implicated in disease pathogenesis. Despite the progress made, unanswered questions and future research directions are discussed to facilitate personalized and targeted therapies for patients with these debilitating conditions.

Development of microRNA-based therapeutics for central nervous system diseases

MicroRNA (miRNA)-mediated gene silencing is a method of RNA interference in which a miRNA binds to messenger RNA sequences and regulates target gene expression. MiRNA-based therapeutics have shown promise in treating a variety of central nervous system diseases, as verified by results from diverse preclinical model organisms. Over the last decade, several miRNA-based therapeutics have entered clinical trials for various kinds of diseases, such as tumors, infections, and inherited diseases. However, such clinical trials for central nervous system diseases are scarce, and many central nervous system diseases, including hemorrhagic stroke, ischemic stroke, traumatic brain injury, intractable epilepsy, and Alzheimer's disease, lack effective treatment. Considering its effectiveness for central nervous system diseases in preclinical experiments, microRNA-based intervention may serve as a promising treatment for these kinds of diseases. This paper reviews basic principles and recent progress of miRNA-based therapeutics and summarizes general procedures to develop such therapeutics for treating central nervous system diseases. Then, the current obstacles in drug development are discussed. This review also provides a new perspective on possible solutions to these obstacles in the future.

A non-invasive strategy for suppressing asthmatic airway inflammation and remodeling: Inhalation of nebulized hypoxic hUCMSC-derived extracellular vesicles

Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) are extremely promising nanoscale cell-free therapeutic agents. We previously identified that intravenous administration (IV) of human umbilical cord MSC-EVs (hUCMSC-EVs), especially hypoxic hUCMSC-EVs (Hypo-EVs), could suppress allergic airway inflammation and remodeling. Here, we further investigated the therapeutic effects of Hypo-EVs administration by atomizing inhalation (INH), which is a non-invasive and efficient drug delivery method for lung diseases. We found that nebulized Hypo-EVs produced by the atomization system (medical/household air compressor and nebulizer) maintained excellent structural integrity. Nebulized Dir-labeled Hypo-EVs inhaled by mice were mainly restricted to lungs. INH administration of Hypo-EVs significantly reduced the airway inflammatory infiltration, decreased the levels of IL-4, IL-5 and IL-13 in bronchoalveolar lavage fluid (BALF), declined the content of OVA-specific IgE in serum, attenuated the goblet cell metaplasia, and the expressions of subepithelial collagen-1 and α-smooth muscle actin (α-SMA). Notably, Hypo-EV INH administration was generally more potent than Hypo-EV IV in suppressing IL-13 levels and collagen-1 and α-SMA expressions. RNA sequencing revealed that various biological processes, such as cell adhesion, innate immune response, B cell activation, and extracellular space, were associated with the activity of Hypo-EV INH against asthma mice. In addition, Hypo-EVs could load exogenous miR-146a-5p (miR-146a-5p-EVs). Furthermore, INH administration of miR-146a-5p-EVs resulted in a significantly increased expression of miR-146a-5p mostly in lungs, and offered greater protection against the OVA-induced increase in airway inflammation, subepithelial collagen accumulation and myofibroblast compared with nebulized Hypo-EVs. Overall, nebulized Hypo-EVs effectively attenuated allergic airway inflammation and remodeling, potentially creating a non-invasive route for the use of MSC-EVs in asthma treatment.

ESP-B4 promotes nasal epithelial cell-derived extracellular vesicles containing miR-146a-5p to modulate Smad3/GATA-3 thus relieving allergic rhinitis: ESP-B4/miR-146a-5p in AR

BACKGROUND

Though generally a mild affliction, allergic rhinitis (AR) is very common and causes considerable discomfort. Ephedra sinica polysaccharide is a candidate cost-effective therapy to relieve AR symptoms.

PURPOSE

We explore the molecular mechanism of pure polysaccharide ESP-B4 action in AR.

METHODS

RPMI2650 cells were treated with lipopolysaccharide to induce an in vitro sensitization model, and extracellular vesicles (EVs) were isolated. A rat model of AR was established using ovalbumin as the allergen and was treated with Ephedra sinica polysaccharide to observe changes in rhinitis symptoms, nasal mucosa histopathology and molecular pathology. ESP-B4-treated sensitized cells were adopted in vitro to verify effect of Ephedra sinica polysaccharide on miR-146a-5p expression in RPMI2650 cell-derived EVs and helper T cell differentiation.

RESULTS

miR-146a-5p inhibited Smad3, impeded the Smad3/GATA-3 interaction, upregulated IFN-γ expression, and promoted CD4⁺T cell Th1 differentiation. Treatment with ESP-B4 relieved AR in rats, and elevated miR-146a-5p in the EVs from the nasal epithelial cells, apparently in relation to effects on helper T cell Th1/Th2 equilibrium.

CONCLUSION

Overall, ESP-B4 can promote miR-146a-5p secretion, affect the Th1/Th2 balance of helper T cells, and relieve AR symptoms through Smad3/GATA-3 interaction, thus presenting a potential strategy for AR treatment.

Interaction between non-coding RNAs and Toll-like receptors

Toll-like receptors (TLRs) are a large group of pattern recognition receptors which are involved in the regulation of innate immune responses. Based on the interplay between TLRs and adapter molecules, two distinctive signaling cascades, namely the MyD88-dependent and TRIF-dependent pathways have been recognized. TLRs are involved in the development of a wide variety of diseases including cancer and autoimmune disorders. A large body of evidence has shown interaction between two classes of non-coding RNAs, namely microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). These interactions have prominent roles in the pathogenesis of several disorders including infectious disorders, autoimmune conditions and neoplastic disorders. This review aims at description of the interaction between these non-coding RNAs and TLRs.

Tectorigenin regulates migration, invasion, and apoptosis in dexamethasone-induced human airway epithelial cells through up-regulating miR-222-3p

Glucocorticoids (GCs) can effectively control airway inflammation, but can also cause airway epithelial injury. Tectorigenin, a type of isoflavone isolated from various medicinal plants, has hypolipidemic activity, hepatoprotective, and antioxidant effects. We aimed to investigate whether Tectorigenin can repair GCs-induced airway epithelial injury. Airway epithelial cell line (9HTE cells) were treated with dexamethasone (Dex), Tectorigenin, or further transfected, then cell viability, migration, and invasion were examined by Cell Counting Kit (CCK-8), wound healing, and Transwell assays. The expressions of potential miRNAs related to the effect of Tectorigenin were detected by quantitative polymerase chain reaction (qPCR). Expressions of poptosis-related proteins Bcl-2-associated protein-X (Bax), B-cell lymphoma-2 (Bcl-2), Cleaved Caspase-3, and related to Mitorgen-activated protein kinase (MAPK) signaling pathway serine/threonine kinase (Raf1), extracellular signal-regulated kinase kinase 1/2 (MEK1/2), and extracellular signal-regulated kinase 1/2 (ERK1/2) were detected by Western blot. Dex inhibited the cell viability, migration and invasion by promoting Bax and Cleaved Caspase-3 expressions (p <.001) and by inhibiting the expressions of Bcl-2 and miR-222-3p (p <.001). Then, 10 μmol/L Tectorigenin itself did not affect cell viability but could inhibit the effect of Dex on cell viability, migration, and invasion. Tectorigenin up-regulated the expressions of miR-222-3p, Bcl-2, p-Raf1, p-MEK1/2, and p-ERK1/2 (p <.01), but down-regulated the expressions of Bax and Cleaved Caspase-3 (p <.05) in Dex-induced cells. MiR-222-3p inhibitor reversed the antagonistic effect of Tectorigenin on Dex. The study demonstrates that Tectorigenin inhibits apoptosis of Dex-induced 9HTE cells by up-regulating the expression of miR-222-3p, which involves with the MAPK pathway.

MicroRNAs as Potential Regulators of Immune Response Networks in Asthma and Chronic Obstructive Pulmonary Disease

Chronic respiratory diseases (CRDs) are an important factor of morbidity and mortality, accounting for approximately 6% of total deaths worldwide. The main CRDs are asthma and chronic obstructive pulmonary disease (COPD). These complex diseases have different triggers including allergens, pollutants, tobacco smoke, and other risk factors. It is important to highlight that although CRDs are incurable, various forms of treatment improve shortness of breath and quality of life. The search for tools that can ensure accurate diagnosis and treatment is crucial. MicroRNAs (miRNAs) are small non-coding RNAs and have been described as promising diagnostic and therapeutic biomarkers for CRDs. They are implicated in multiple processes of asthma and COPD, regulating pathways associated with inflammation, thereby showing that miRNAs are critical regulators of the immune response. Indeed, miRNAs have been found to be deregulated in several biofluids (sputum, bronchoalveolar lavage, and serum) and in both structural lung and immune cells of patients in comparison to healthy subjects, showing their potential role as biomarkers. Also, miRNAs play a part in the development or termination of histopathological changes and comorbidities, revealing the complexity of miRNA regulation and opening up new treatment possibilities. Finally, miRNAs have been proposed as prognostic tools in response to both conventional and biologic treatments for asthma or COPD, and miRNA-based treatment has emerged as a potential approach for clinical intervention in these respiratory diseases; however, this field is still in development. The present review applies a systems biology approach to the understanding of miRNA regulatory networks in asthma and COPD, summarizing their roles in pathophysiology, diagnosis, and treatment.

Hypoxic hUCMSC-derived extracellular vesicles attenuate allergic airway inflammation and airway remodeling in chronic asthma mice

BACKGROUND

As one of the main functional forms of mesenchymal stem cells (MSCs), MSC-derived extracellular vesicles (MSC-EVs) have shown an alternative therapeutic option in experimental models of allergic asthma. Oxygen concentration plays an important role in the self-renewal, proliferation, and EV release of MSCs and a recent study found that the anti-asthma effect of MSCs was enhanced by culture in hypoxic conditions. However, the potential of hypoxic MSC-derived EVs (Hypo-EVs) in asthma is still unknown.

METHODS

BALB/c female mice were sensitized and challenged with ovalbumin (OVA), and each group received PBS, normoxic human umbilical cord MSC-EVs (Nor-EVs), or Hypo-EVs weekly. After treatment, the animals were euthanized, and their lungs and bronchoalveolar lavage fluid (BALF) were collected. With the use of hematoxylin and eosin (HE), periodic acid-Schiff (PAS) and Masson's trichrome staining, enzyme-linked immune sorbent assay (ELISA), Western blot analysis, and real-time PCR, the inflammation and collagen fiber content of airways and lung parenchyma were investigated.

RESULTS

Hypoxic environment can promote human umbilical cord MSCs (hUCMSCs) to release more EVs. In OVA animals, the administration of Nor-EVs or Hypo-EVs significantly ameliorated the BALF total cells, eosinophils, and pro-inflammatory mediators (IL-4 and IL-13) in asthmatic mice. Moreover, Hypo-EVs were generally more potent than Nor-EVs in suppressing airway inflammation in asthmatic mice. Compared with Nor-EVs, Hypo-EVs further prevented mouse chronic allergic airway remodeling, concomitant with the decreased expression of pro-fibrogenic markers α-smooth muscle actin (α-SMA), collagen-1, and TGF-β1-p-smad2/3 signaling pathway. In vitro, Hypo-EVs decreased the expression of p-smad2/3, α-SMA, and collagen-1 in HLF-1 cells (human lung fibroblasts) stimulated by TGF-β1. In addition, we showed that miR-146a-5p was enriched in Hypo-EVs compared with that in Nor-EVs, and Hypo-EV administration unregulated the miR-146a-5p expression both in asthma mice lung tissues and in TGF-β1-treated HLF-1. More importantly, decreased miR-146a-5p expression in Hypo-EVs impaired Hypo-EV-mediated lung protection in OVA mice.

CONCLUSION

Our findings provided the first evidence that hypoxic hUCMSC-derived EVs attenuated allergic airway inflammation and airway remodeling in chronic asthma mice, potentially creating new avenues for the treatment of asthma.