Zhong S, Chen C, Liu N, et al. - Researchers looked for regulatory roles of special miRNA–mRNA axis in chronic obstructive pulmonary disease (COPD) development. They used the LIMMA package in R software to screen differentially expressed miRNAs and downstream mRNAs from the Gene Expression Omnibus dataset. They developed a co-expression network for COPD by using weighted Gene Co-expression Network Analysis. In vitro study was performed to determine the regulatory roles of candidate miRNAs and targeted mRNAs. In COPD patients, significant upregulation of hsa-miR-664a-3p was confirmed in this study. The downregulation of its target gene FHL1, as well as its positive correlation with forced expiratory volume in 1 sec/FVC% (forced vital capacity), was evident; cigarette smoke extract could regulate both hsa-miR-664a-3p and FHL1. A possible pivotal role of the axis from hsa-miR-664a-3p to FHL1 in cigarette smoke-induced COPD was indicated by bioinformatic analyses and expanded validation.