C70-21 Sex-Specific Transcriptional Networks Associated With Elexacaftor-Tezacaftor-Ivacaftor (ETI) Therapies

Abstract Rationale Cystic Fibrosis (CF) results from variants in the CF transmembrane conductance regulator (CFTR) gene. Sexual dimorphism in clinical features associated with CF is well documented. Untreated females experience more frequent pulmonary exacerbations and have worse lung function, as measured by forced expiratory volume (FEV1), compared to their male counterparts. Triple combination CFTR modulators, like Elexacaftor-Tezacaftor-Ivacaftor (ETI), are associated with improved FEV1 and lower exacerbation rates. However, sexual disparities persist after ETI treatment, with females continuing to experience worse pulmonary morbidity than males . Here, we aim to identify ETI-sensitive networks that could serve as therapeutic targets for modulating inflammation. Methods We conducted a study that compared the immune transcriptional networks of patients affiliated with the Yale Adult CF Program (5 males M, 7 females F ) before and after starting ETI therapy. Sputum samples were collected from CF patients prior to beginning ETI therapy and at least 30 days after starting ETI therapy. Following sputum induction, we generated cDNA libraries from single cells following our previously established scRNAseq protocols. We defined four analysis groups based on sex (M, F) and treatment condition (untreated, ETI treated). We utilized a standardized Connectome pipeline (R package Seurat 4.3.1) to investigate how transcriptional networks shift following ETI treatment. Results We identified potential signaling networks as the interaction between ligand and receptor genes. The collection of networks established between signaling and receiving networks was defined as the Connectome. The thickness of each gene-gene interaction is known as edgeweight (w), the scaled and normalized product of the average expression of both genes. A thicker edgeweight represents a stronger connection between a ligand and its receptor. In females, the IL1RN to IL1R2 edgeweight (wuntreated=0.50, wETI=0.70, diff=0.20) and the IL15 to IL2RA edgeweight (wuntreated=0.017, wETI=0.20, diff=0.18) increased after ETI therapy. However, in males, the IL1RN to IL1R2 (wuntreated=0.44, wETI=0.28, diff=-0.16) edgeweight decreased and the IL15 to IL2RA edgeweight remained relatively constant after ETI therapy (wuntreated=0.026, wETI=0.006, diff=-0.02). Overall, we observed a reduction in outgoing monocyte signaling and in the total number of edgeweights formed between monocytes and other cell types in ETI-treated females. Conclusion These findings suggest that sex-specific differential monocyte expression is not limited to individual genes but also extends to multiple genes within signaling pathways. These subgroup-specific differentially expressed networks show promise for the development of personalized therapeutic approaches to narrow the sex gap in sexually dimorphic features of CF. This abstract is funded by: CFF, NIH