Expression of Serum MicroRNAs 221, 222, 15a and Level of VEGF-A in Children with Bronchial Asthma.

Bronchial asthma (BA) remains the most common chronic respiratory disease in children and is characterized by reversible airway obstruction and airway hyperresponsiveness. MicroRNAs (miRNAs) are a class of small, highly conserved non-coding RNA molecules that regulate gene expression at the posttranscriptional level. MiRNAs can either augment or minimize the allergic inflammation in asthma. It has been noted that a group of miRNAs may affect the development of asthma and related inflammatory response. The vascular endothelial growth factor (VEGF) is produced by different types of cells and has a major role in both, physiological and pathological angiogenesis. Our aim was to study serum expression of three microRNAs; 221, 222,15a and Vascular Endothelial Growth Factor A (VEGF-A) levels in children with bronchial asthma. The study included 30 children with BA and a control group of 20 apparently healthy, age and sex matched, children. Quantitative reverse transcription (q RT) polymerase chain reaction (PCR) was performed to examine the expression levels of miR-221, 222 and 15a in patients' sera. Levels of serum VEGF-A were quantified utilizing an ELISA technique. Serum levels of both miRNA-221 and miRNA-222 were not significantly different between pediatric asthmatic patients versus controls (P=0.76 and 0.52, respectively), but showed increase with the disease severity (persistent versus intermittent) (P= 0.09, 0.07, respectively). Serum miRNA-15a expression was significantly down-regulated in asthmatic patients versus the control group (P=0.03). miRNA-15a expression did not differ among various grades of BA (P=0.33) and was not correlated with serum levels of VEGF-A (P=0.56). The level of VEGF-A was significantly increased in serum of pediatrics with bronchial asthma in comparison to the control group (P=0.026). In conclusion, miRNA-15a and VEGF-A may have a role in BA pathogenesis, while miRNA-221 and 222 may reflect BA disease severity. Copyright© by the Egyptian Association of Immunologists.