miR-34a in serum is involved in mild-to-moderate COPD in women exposed to biomass smoke

Abstract

Abstract Background Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities. The main causes of COPD are Gene-environment interactions associated with tobacco smoking (COPD-TS) and biomass smoke (COPD-BS). It is well know that microRNAs (miRNAs) participate in the control of post-transcriptional regulation and are involved in COPD-TS; nevertheless, those miRNAS are participating in the COPD-BS are unidentified. Thus, we studied which miRNAs are involved in COPD-BS (GOLD stages I–II). Methods In the screening phase, the profile of the miRNAs was analyzed in serum samples (n = 3) by means of a PCR array. Subsequently, the miRNAs were validated with RT-qPCR (n = 25) in the corresponding study groups. Additionally, the serum concentration of Notch1 was measured comparing COPD-BS vs COPD-TS. Results miR-34a was down-regulated in COPD- BS vs COPD-TS. In the other study groups, three miRNAs were differentially expressed: miR-374a was down-regulated in COPD-BS vs C, miR-191-5p was up-regulated in COPD-BS vs H-BS, and miR-21-5p was down-regulated in COPD-TS compared to the C group. Moreover, the serum concentration of Notch1, one of the targets of miR-34a, was increased in COPD-BS compared to women with COPD-TS. Conclusions This is the first study in patients with COPD due to biomass that demonstrates miRNA expression differences between patients. The observations support the concept that COPD by biomass has a different phenotype than COPD due to tobacco smoking, which could have important implications for the treatment of these diseases.

Keywords

• Biomass smoke exposure
• COPD
• microRNAs
• PCR arrays
• RT-qPCR
• Tobacco smoking