MiR-146a overexpression effectively improves experimental allergic conjunctivitis through regulating CD4+CD25-T cells

Challenging corneal diseases and microRNA expression: Focus on rare diseases and new therapeutic frontiers

MicroRNAs (miRNAs) function as posttranscriptional regulators of gene expression by targeting specific messenger RNA (mRNA). This interaction modulates mRNA stability or translational efficiency, ultimately impacting the level of protein production. Emerging evidence suggests that miRNAs act as critical regulators in corneal diseases. These molecules finetune key processes like cell proliferation, differentiation, inflammation, and wound healing. We reviewed the literature to understand the role that miRNAs may play in the development of challenging and poorly understood corneal diseases. We focused on vernal keratoconjunctivitis, neurotrophic keratitis, keratoconus, Fuchs endothelial corneal dystrophy, and limbal stem cell deficiency. Furthermore, we explored currently studied agonists or antagonists of miRNAs that share similar pathways with ocular diseases and could be employed in ophthalmology in the future. The distinct miRNA expression profiles observed in different ocular surface pathologies, combined with the remarkable stability and relatively easy access of miRNA sampling in biofluids, present possibilities for the development of noninvasive and highly accurate diagnostic tools. Furthermore, comprehending miRNA's pathophysiological role could open new frontiers to a more comprehensive understanding of the pathophysiology underlying ocular surface diseases, thereby paving the way for the creation of novel therapeutic strategies.

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.

Development of a Temperature and pH Dual-Sensitive In-Situ Gel for Treating Allergic Conjunctivitis

The purpose of this study was to improve the efficacy of olopatadine hydrochloride (OT) in treating allergic conjunctivitis (AC). To achieve this goal, we developed an eye formulation without antimicrobial agents using a temperature-pH dual-sensitive in situ gel technology combined with heat sterilization. Various types of carbomers were evaluated and their optimal doses determined. The prescription containing poloxamer 407 (P407) and poloxamer 188 (P188) was optimized using central composite design for response surface methodology (CCD-RSM). The final optimized dual-sensitive in situ gel (TP-gel) consisted of 0.1% olopatadine hydrochloride, 18.80% P407, 0.40% P188, 0.30% Pemulen™TR-1(TR-1), 4.0% mannitol, and 0.08% Tri(hydroxymethyl)aminomethane(Tris).Sterilization was performed at a temperature of 121℃ for a duration of 20 min. Experimental results showed that TP-gel had good safety profile and remained on the ocular surface for approximately (65.83 ± 8.79) minutes, which is four times longer than eye drops. The expression levels of IL-13, IL-17, and OVA-IgE in mouse ocular tissues with allergic conjunctivitis treated with TP-gel were significantly reduced. This suggests that TP-gel has the potential to be an effective treatment method for allergic conjunctivitis.

miR‑146a‑5p negatively regulates the IL‑1β‑stimulated inflammatory response via downregulation of the IRAK1/TRAF6 signaling pathway in human intestinal epithelial cells

The primary pathophysiological alteration caused by inflammatory bowel disease (IBD) is prolonged, excessive inflammatory response to stimulation factors, which leads to intestinal mucosal lesions. microRNA (miR)-146a-5p is broadly activated in the mucosal immune response. At present, the biogenesis, function and role of miR-146a-5p in intestinal epithelial cells (IECs) during the pathogenesis of IBD remain elusive. The human colon cancer epithelial Caco-2 cell line was cultured with 10 ng/ml recombinant human IL-1β for 3 h to establish an in vitro IECs inflammatory model. Relative levels of miR-146a-5p and inflammatory factors (IL-6, IL-1β, TNF-α and IP-10) were measured by reverse transcription-quantitative PCR (RT-qPCR) and western blotting. Transfection of miR-146a-5p mimic or inhibitor into Caco-2 cells was performed to identify the influence of miR-146a-5p on Caco-2 cell inflammatory factors expression. The targeting relationship between miR-146a-5p and interleukin 1 receptor associated kinase 1 (IRAK1)/tumor necrosis factor receptor-associated factor 6 (TRAF6) was predicted by TargetScan 8.0. The present study demonstrated that miR-146a-5p and inflammatory factors (IL-6, IL-1β, TNF-α and IP-10) were upregulated in a dose- and time-dependent manner in IL-1β-stimulated Caco-2 cells. Moreover, upregulation of miR-146a-5p negatively regulated the expression of inflammatory factors, but the downregulation of miR-146a-5p increased their expression. The results of the present study demonstrated that miR-146a-5p decreased the expression of the inflammatory factors through targeted downregulation of IRAK1/TRAF6. These results suggest that miR-146a-5p negatively regulates the IL-1β-stimulated inflammatory response via downregulation of the IRAK1/TRAF6 signaling pathway in human IECs. Therefore, miR-146a-5p may act as an important diagnostic biomarker and treatment target of IBD.

miRNA profiles change during grass pollen immunotherapy irrespective of clinical outcome

Background: Subcutaneous immunotherapy (SCIT) is widely used in the treatment of allergic rhinitis (AR). This study aimed to determine the expression of 48 miRNAs in patients with AR undergoing grass pollen SCIT and investigate relations with clinical outcomes. Methodology: Expression of selected miRNAs was determined using RT-PCR in the full blood of 16 patients with AR and seven healthy controls. Results: miR-136, miR-208 and miR-190 were upregulated in the AR group. After 6 months of SCIT, significant downregulation of some proinflammatory miRNAs and upregulation of several miRNAs regulating Th1/Th2 balance were found. No differences were found between good and poor responders. Conclusion: miRNAs may play a regulatory role in SCIT, leading to tolerance induction.

Emerging Roles of Non-Coding RNAs in Childhood Asthma

Asthma is a chronic airway inflammatory disease in children characterized by airway inflammation, airway hyperresponsiveness and airway remodeling. Childhood asthma is usually associated with allergy and atopy, unlike adult asthma, which is commonly associated with obesity, smoking, etc. The pathogenesis and diagnosis of childhood asthma also remains more challenging than adult asthma, such as many diseases showing similar symptoms may coexist and be confused with asthma. In terms of the treatment, although most childhood asthma can potentially be self-managed and controlled with drugs, approximately 5-10% of children suffer from severe uncontrolled asthma, which carries significant health and socioeconomic burdens. Therefore, it is necessary to explore the pathogenesis of childhood asthma from a new perspective. Studies have revealed that non-coding RNAs (ncRNAs) are involved in the regulation of respiratory diseases. In addition, altered expression of ncRNAs in blood, and in condensate of sputum or exhalation affects the progression of asthma via regulating immune response. In this review, we outline the regulation and pathogenesis of asthma and summarize the role of ncRNAs in childhood asthma. We also hold promise that ncRNAs may be used for the development of biomarkers and support a new therapeutic strategy for childhood asthma.

Emerging Advances of Non-coding RNAs and Competitive Endogenous RNA Regulatory Networks in Asthma

Asthma is a chronic inflammatory disease characterized by airway remodeling and bronchial hyperresponsiveness. A variety of effector cells and cytokines jointly stimulate the occurrence of inflammatory response in asthma. Although the pathogenesis of asthma is not entirely clear, the possible roles of non-coding RNAs (ncRNAs) have been recently demonstrated. NcRNAs are non-protein-coding RNA molecules, such as circular RNAs (circRNAs), long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), which are involved in the regulation of a variety of biological processes. Mounting studies have shown that ncRNAs play pivotal roles in the occurrence and progression of asthma via competing endogenous RNA (ceRNA) regulatory networks. However, the specific mechanism and clinical application of ncRNAs and ceRNA regulatory networks in asthma have not been fully elucidated, which are worthy of further investigation. This paper comprehensively summarized the current progress on the roles of miRNAs, lncRNAs, circRNAs, and ceRNA regulatory networks in asthma, which can provide a better understanding for the disease pathogenesis and is helpful for identifying novel biomarkers for asthma.

MiR-21-5p in Macrophage-Derived Exosomes Targets Smad7 to Promote Epithelial Mesenchymal Transition of Airway Epithelial Cells

Background

Asthma is usually associated with airway inflammation and airway remodeling. Epithelial mesenchymal transition (EMT) often occurs in airway remodeling. The purpose of this study is to identify the effect of miR-21-5p and Smad7 signaling pathway in macrophage-derived exosomes on EMT of airway epithelial cells.

Methods

HE staining and Masson staining were used to verify the successful establishment of the asthma model. The levels of epithelial cell adhesion factor and stromal cell markers were detected by Western blot. The levels of miR-21-5p were detected by qRT-PCR. The expression of miR-21-5p in lung tissue was further verified by fluorescence in situ hybridization (FISH). Exosome morphology was observed by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Luciferase reporter assay was applied to analyze the interaction of miR-21-5p with Smad7.

Results

The expression of miR-21-5p was upregulated in macrophages of rats in vivo with OVA-induced asthma. In vitro cultured alveolar macrophages stimulated by LPS could secrete exosomes with high levels of miR-21-5p. The exosome-derived miR-21-5p promotes EMT in rat tracheal epithelial cells through TGFβ1/Smad signaling pathway by downregulating Smad7. This process can be blocked by miR-21-5p inhibitor.

Conclusion

Rat alveolar macrophages produced high levels of miR-21-5p-containing exosomes, which transported miR-21-5p to tracheal epithelial cells, thus promoting EMT through TGF-β1/Smad signaling pathway by targeting Smad7.

Lactobacillus acidophilus KLDS 1.0738 inhibits TLR4/NF-κB inflammatory pathway in β-lactoglobulin-induced macrophages via modulating miR-146a

Our previous study has confirmed that Lactobacillus acidophilus KLDS 1.0738 (La KLDS 1.0738) could alleviate β-lactoglobulin (β-Lg)-induced allergic inflammation. This study further explored its molecular regulation mechanism through an in vitro macrophage model. β-Lg-induced macrophages were treated with strains of viable or non-viable L. acidophilus and Toll-like receptor 4 (TLR4) inhibitor or miR-146a inhibitor. Our results revealed that β-Lg stimulation led to the increased expression of TLR4/NF-κB signal pathway in macrophages. Similar to TLR4 inhibitor treatment, La KLDS 1.0738 interventions significantly reduced the allergic inflammation by inhibition of TLR4 pathway, which was superior to the commercial L. acidophilus GMNL-185 strains (La GMNL-185) or the control, especially in living L. acidophilus-treated group. Furthermore, La KLDS 1.0738 strains could remarkably reduce transduction of TLR4 and inflammatory cytokine production, which was closely associated with up-regulation of miR-146a levels. MiR-146a inhibitor attenuated the alleviative effect of La KLDS 1.0738, indicating miR-146a might be a crucial mediator of L. acidophilus strains to reduce β-Lg-induced inflammation in macrophages through TLR4 pathway. In conclusion, these observations highlighted that probiotics might regulate host miRNA levels to down-regulate TLR4/NF-κB-dependent inflammation. PRACTICAL APPLICATIONS: Cow's milk allergy (CMA) is one of the most common diseases of food allergy, which has a high prevalence in infants and young children. La KLDS 1.0738 has been shown to be effective in alleviating β-Lg-induced allergic inflammation. Our study further found that treatment with La KLDS 1.0738 could suppress the TLR4/NF-κB signaling pathway via modulating miR-146a expression, thereby reducing the overexpression of downstream inflammatory factors. This study not only elucidates the specific pathway of La KLDS 1.0738 to relieve allergic inflammation, but also provides a new insight into the molecular mechanism for the remission and treatment of CMA by probiotics.

MicroRNAs: future biomarkers and targets of therapy in asthma?

PURPOSE OF REVIEW

MicroRNAs (miRNAs) are small noncoding RNA molecules that are considered one of the fundamental regulatory mechanisms of gene expression. They are involved in many biologic processes, such as signal transduction, cell proliferation and differentiation, apoptosis and stress responses. The purpose of this review is to present recent knowledge about the role of miRNAs in asthma and outline possible applications of miRNAs.

RECENT FINDINGS

A core set of miRNAs involved in asthma includes downregulated let-7 family, miR-193b, miR-375 as well as upregulated miR-21, miR-223, miR-146a, miR-142-5p, miR-142-3p, miR-146b and miR-155. Recently it has been shown that most of the involved miRNAs increase secretion of Th2 cytokines, decrease secretion of Th1 cytokines, promote differentiation of T cells towards Th2 or play a role in hyperplasia and hypertrophy of bronchial smooth muscle cells. The profiles of miRNAs correlate with clinical characteristics, including lung function, phenotype and severity of asthma.

SUMMARY

Recent publications confirmed crucial regulatory role of miRNAs in the pathomechanism of asthma. Some single miRNAs or their sets hold the promise for their use as asthma biomarkers facilitating diagnosis or prediction of treatment outcomes. They are also possible target of future therapies. The studies in this field are lacking though.

MicroRNAs: Potential Biomarkers and Targets of Therapy in Allergic Diseases?

MicroRNAs (miRNAs) are small non-coding RNA molecules that are 18-22 nucleotides long and highly conserved throughout evolution. Currently, they are considered one of the fundamental regulatory mechanisms of genes expression. It has been demonstrated that miRNAs are involved in many biologic processes, such as signal transduction, cell proliferation and differentiation, apoptosis and stress responses. More recently, the role of miRNA has also been revealed in numerous immunological and inflammatory disorders, including allergic inflammation. Specific miRNA profiles were demonstrated in asthma, allergic rhinitis and atopic dermatitis. A core set of miRNAs involved in atopic diseases include upregulated miR-21, miR-223, miR-146a, miR-142-5p, miR-142-3p, miR-146b, miR-155 and downregulated let-7 family, miR-193b and miR-375. Most of the involved miRNAs increase secretion of Th2 cytokines (miR-1248, miR-146b), decrease secretion of Th1 cytokines (miR-513-5p, miR-625-5p) or promote differentiation of T cells towards Th2 (miR-21, miR-19a). In asthma miR-140-3p, miR-708 and miR-142-3p play a role in hyperplasia and hypertrophy of bronchial smooth muscle cells. Some single miRNAs or, more probably, their sets hold the promise for their use as biomarkers of atopic diseases. They are also promising target of future therapies.