Impact of overexpression of wild-type CFTR and elexacaftor-tezacaftor-ivacaftor on oxylipin production by the CFBE41o- bronchial epithelial cell line.

A hallmark of cystic fibrosis (CF) is dysregulated lipid metabolism marked by an imbalance of pro-inflammatory to pro-resolving metabolites. Despite the breadth of evidence associating mutation of the cystic fibrosis conductance regulator (CFTR) with dysregulation of the production of oxylipins, oxidized lipid mediators with specialized functions generated during inflammation, few studies have directly measured whether overexpression of wild-type (WT) CFTR is sufficient to equilibrate oxylipin levels in CF models. In this study, targeted lipidomics was used to compare the oxylipin profiles of the parental CFBE41o- immortalized bronchial epithelial cell line homozygous for F508del CFTR, the most common CFTR mutation in people with CF, with the same cell line overexpressing WT CFTR (CFBE41o- o/e WT CFTR). Overexpression of WT CFTR in the CFBE41o- background resulted in decreased production of prostaglandins and increased production of precursors of specialized pro-resolving mediators, including 14,15-epoxyeicosatrienoic acid (14(15)-EET) compared to the parent CFBE41o- cell line, likely due to a decrease in production of inducible COX-2 associated with inflammation and an increase in COX-1 and PPARγ associated with resolution of inflammation. Additionally, highly effective modulator therapy (HEMT) improves pulmonary health for people with CF (PwCF) by targeting the underlying biochemical dysfunction of mutant CFTR. However, its impact on dysregulated lipid metabolism remains under-investigated. Despite inducing production and trafficking of F508del CFTR, treatment of the CFBE41o- parental cell line monolayers with the HEMT elexacaftor-tezacaftor-ivacaftor (ETI) increased levels of the prostaglandin E2 (PGE2). This disparity in cellular response by CFBE41o- cells to overexpression of WT CFTR and exposure to ETI was due to differences in production of prostaglandin biosynthetic and regulatory proteins upstream of oxylipin biosynthesis.