PTGS2 and chronic obstructive pulmonary disease: In line with this hypothesis the relative production of the proteoglycan versican as well as the expression of the pro-inflammatory enzyme cyclooxygenase-2 (COX-2), both direct targets of WNT/β-catenin signaling [29], [49], [50], are higher in parenchymal fibroblasts from COPD patients than controls [15], [17].