Salivary microRNAs in pediatric eosinophilic esophagitis.

Background: Diagnosis and management of eosinophilic esophagitis (EoE) occur via esophagogastroduodenoscopy with tissue biopsy. Objective: We sought to determine if salivary microribonucleic acid (miRNA) levels could differentiate children with EoE, serving as a noninvasive biomarker. Methods: Saliva was collected from children undergoing esophagogastroduodenoscopy (N = 291). miRNA analysis was conducted on 150 samples: EoE (n = 50), no pathologic alteration (n = 100). RNA was quantified with high throughput sequencing and aligned to build hg38 of the human genome using sequencing and alignment software. Quantile normalized levels of robustly expressed miRNAs (raw counts > 10 in 10% of samples) were compared across EoE and non-EoE groups with Wilcoxon rank sum testing. miRNA biomarker candidates were selected based on variable importance projection (VIP) scoring with partial least squared discriminant analysis (VIP > 1.5). Ability of these miRNAs to differentiate EoE status was assessed via logistic regression. Putative biologic targets for the miRNA candidates were determined in miRNA pathway analysis software. Results: Of the 56 salivary miRNAs reliably detected, miR-205-5p displayed the largest difference between EoE and non-EoE groups (V = 1623, adjusted p = 0.029). Six miRNAs (miR-26b-5p, miR-27b-3p, Let-7i-5p, miR-142-5p, miR-30a-5p, miR-205-5p) displayed elevated VIP scores (>1.5) and were able to differentiate EoE samples on logistic regression analysis with 70% sensitivity and 68% specificity. These six miRNAs demonstrated significant enrichment for gene targets involved in valine, leucine, and isoleucine biosynthesis (p = 0.0012), 2-oxycarboxylic acid metabolism (p = 0.043), and steroid hormone biosynthesis (p = 0.048). Conclusions: Salivary miRNAs represent a noninvasive, biologically relevant measure that may aid disease monitoring of EoE.

Isolation and profiling of plasma microRNAs: Biomarkers for asthma and allergic rhinitis.

Chronic inflammatory diseases can be particularly challenging to diagnose and characterize, as inflammatory changes in tissue may not be present in blood. There is a crucial need to develop non-invasive biomarkers that would be useful in diagnosing disease and selecting medical therapies. For example, there are no blood tests to diagnose asthma, a common inflammatory lung disease. MicroRNA (miRNA) expression profiling in blood is emerging as a potentially sensitive and useful biomarker of many diseases. In particular, we have characterized a cost-effective PCR-based array technology to measure and profile circulating miRNAs in the plasma of patients with allergic rhinitis and asthma. Here, we describe the methods to isolate, quantify, and analyze miRNAs in the plasma of human subjects as well as ways to determine their diagnostic utility.

MicroRNA-146a is induced by inflammatory stimuli in airway epithelial cells and augments the anti-inflammatory effects of glucocorticoids.

BACKGROUND: MicroRNAs (miRNAs) are emerging as central regulators of inflammation, but their role in asthma and airway epithelial cells is not well studied. Glucocorticoids are the cornerstone of therapy in asthma and other inflammatory disease, yet their mechanisms of action are not completely elucidated, and it is not clear whether miRNAs modulate their effects. OBJECTIVE: We aimed to identify miRNAs that regulate cytokine and chemokine expression in airway epithelial cells and whether these miRNAs are subject to the effects of glucocorticoids. METHODS AND RESULTS: MicroRNAomic analyses of immortalized, normal human bronchial epithelial cells identified 7 miRNAs that were altered by inflammatory cytokine treatment and 22 that were regulated by glucocorticoids (n = 3 for each treatment condition). MiR-146a emerged as a central candidate, whose expression was induced by TNF-α and repressed by glucocorticoids. Its role as a candidate in asthmatic inflammation was supported by expression profiling in human asthmatics, which showed that plasma miR-146a expression was elevated in asthma and associated with measures related to worse asthma outcomes, including elevated blood eosinophil counts, higher asthma control questionnaire scores, and need for higher doses of inhaled glucocorticoids. However, transfection of miR-146a in A549 cells treated with TNF-α +/- glucocorticoids produced an anti-inflammatory effect and increased efficacy of glucocorticoids. CONCLUSIONS: We propose a model whereby miR-146a is induced by inflammatory conditions as a feedback mechanism to limit inflammation. Exogenous administration of miR-146a augmented the effects of glucocorticoids and could be a novel therapeutic strategy to enhance efficacy of these medications.