RESUMO
Background: COPD is characterized by a persistent inflammatory response, especially against cigarette smoke. COPD patients may develop varying degrees of emphysematous destruction of the lungs. A pathophysiological role for miRNAs in COPD has been suggested in several studies. We examined changes in microRNAs expression profile during 10 years follow-up in relation to COPD progression. Methods: Clinical and lung function parameters were registered from every subject included in the study. miRNAs expression was determined in 14 serum samples from 7 patients in two moments (4 smokers with COPD (BODE cohort) and 3 smokers without COPD) by next generation sequencing (NGS) at baseline and after 10 years follow-up. A validation study was performed by qPCR in 20 patients with COPD (13 emphysema-diagnosed by CTscan) and 10 smoker controls at baseline and after 10 years follow-up. hsa-miRNA-20a-5p and hsa-let-7d-5p were used as endogenous controls. Results: A total of 198 miRNAs (≥10TPM) were identified by NGS. Between these, hsa-miR-1246 was found significantly downregulated in COPD patients after 10 years when compared to baseline (p<0.0001, FDR=0.05). Seventy-five percent of these patients had an emphysema diagnose. In the validation analysis, when analyzed longitudinally, hsa-miR-1246 was significantly downregulated in COPD patients with emphysema after 10 years (p= 0.019). However, no association was found between the expression of miR-1246 and any other lung function parameters (FEV1, PaO2, DLCO, IC/TLC) within the follow-up period. GO and KEGG enrichment analysis revealed miR-1246 to be associated with target genes in several pathways involved in COPD/emphysema development. Conclusion: Our findings suggest that hsa-miR-1246 may act as a biomarker of emphysema in COPD. Functional analysis is guaranteed to elucidate its role in COPD.