MicroRNAs are inversely correlated with biological pathways downregulated with increasing regional emphysema severity. Expression-based association matrix of the 35 significantly upregulated microRNAs (rows) and those MSigDB canonical pathway gene sets (columns) that are significantly enriched amongst genes correlated with the microRNA (FDR <0.25). Red indicates positive correlation, blue indicates negative correlation, and white indicates no significant correlation. The color bar at the top of the heatmap indicates pathways also correlated with emphysema (FDR <0.25) where red indicates positive correlation and grey negative correlation. The grey and white bar below the heatmap highlights clusters of downregulated pathways. The group of pathways indicated by bar 1 includes those most downregulated with emphysema (for example, those involved in ECM maintenance and cell signaling). The second bar highlights an additional cluster of pathways most anti-correlated with upregulated microRNA expression; it includes mainly pathways involved in RNA transcription and processing, cell cycle progression, mitochondrial functioning, DNA repair, and protein degradation.