Differential expression of microRNAs in exhaled breath condensates of patients with asthma, patients with chronic obstructive pulmonary disease, and healthy adults

Let-7a is differentially expressed in bronchial biopsies of patients with severe asthma

“…Let-7a was also found to be reduced in the airway epithelial cells 12 and serum 15 of asthma patients. Thus, reduced expression of let-7a in bronchial biopsies from patients with severe asthma is consistent with the findings of other studies 3,[10][11][12][13][14][15]19,25 . Similar to let-7a, inconsistent results on miR-21 and miR-223 expression in asthma have also been reported 12,15,19,26,27 .…”

“…However, the data on miRNA expression in the lungs of human subjects with asthma are still scarce. Several miRNAs, such as let7a, miR-21, and miR-223, have been shown to have a role in airway inflammation, T H 1/T H 2 polarization, and eosinophil development either directly or indirectly repress the translation of several crucial factors, and were shown to be differentially expressed in asthma 3,4,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . In the present study we analyzed the expression of three miRNAs (let-7a, miR-21, and miR-223) in bronchial biopsy samples from patients with mild and severe asthma and non-asthmatic controls.…”

“…On the other hand, other studies have demonstrated reduced let-7a expression in asthma patients. Pinkerton et al examined miRNA expression in exhaled breath condensate in asthma patients, and found let-7a levels to be lower than in COPD and in healthy controls 14 . A microarray analysis performed on bronchoalveolar lavage fluid exosomes of asthma patients revealed 8 qPCR confirmed altered miRNAs, including down-regulated let-7a and miR-21.…”

“…The variability in treatment response is based on large asthma clinical heterogeneity, and understanding the pattern of airway inflammation and molecular factors regulating those processes could be helpful in defining asthma endotypes and understanding why therapy is not effective in all patients 6 . MicroRNAs (miRNAs), 19-25 nucleotides long non-coding small RNAs involved in regulation of gene expression through a process known as RNA interference 729 , may play a role in orchestrating the phenotypic programming of immune and airway epithelial cells to enhance the production of cytokines and other mediators that result in the inflammation that characterizes asthma 3,4,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . Therefore, miRNAs may contribute to asthma pathology.…”

The role of microRNAs in chronic respiratory disease: recent insights

“…Through miRNA profiling, several groups identified panels of miRNAs to be misregulated in serum, exhaled breath condensates, and in peripheral blood mononuclear cells from COPD patients compared to controls (Akbas et al, 2012;Pinkerton et al, 2013;Dang et al, 2017). Significantly higher levels of miR-21 and lower levels of miR-181a were evident in serum from individuals with COPD and asymptomatic heavy smokers, and an increased ratio of miR-21:miR-181a was associated with disease severity, implicating high miR-21 levels as a risk factor for COPD development (Xie et al, 2014).…”