Analysis of serum micro-RNAs as potential biomarker in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) as a complex disease with genetic and environmental compound is one of the leading causes of death in worldwide. This disease is characterized by lower airway inflammation, and increases risk of lung cancer in smokers. Micro-RNA (miRNA) molecules are key regulators in gene expression that have been widely associated with a several diseases. Differential expression of miRNAs is involved in lung tissue of COPD, but there is no information about biomarker potential of circulating miRNAs in patients. To analyze the miRNA expression profile in COPD, levels of serum miRNAs were profiled by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) array system. The authors examined 72 miRNAs by qRT-PCR array, in 20 COPD patients and 12 control subjects. U6snRNA was used for normalization of the expression of miRNAs for each sample. According to the results, 5 miRNAs were found to be significantly dysregulated. There was down-regulation of miR-20a, miR-28-3p, miR-34c-5p, and miR-100, and up-regulation of miR-7, compared with the controls. This was the first study in COPD for screening of serum miRNAs for searching for biomarker. These results are preliminary screening data and should be confirmed with large patient groups. If so, these miRNAs are likely being involved in pathogenesis of COPD and may give clues for designing therapeutic strategy.