CH25H and chronic obstructive pulmonary disease: CH25H upregulation is driven by TLR4 Myd88‐independent signaling (Diczfalusy et al, 2009), and indeed, GSEA revealed a strong enrichment of both total TLR‐ and TLR4‐dependent signaling in small airway epithelial cells taken from the lungs of COPD patients compared to smoking controls (Fig EV1B).