EDA Fibronectin Contributes to Epithelial-to-Mesenchymal Transition and Peritoneal Fibrosis in a Murine Model of Peritoneal Fibrosis

Background: Peritoneal dialysis (PD) is an important mode of renal replacement therapy and long-term treatment is dependent on the structural and functional integrity of the peritoneum. We previously demonstrated that extra domain A-spliced variant of fibronectin (EDA FN) contributed to peritoneal inflammation and fibrosis. This study investigated changes in transcriptomic profiling and molecular pathways in the peritoneum of mice maintained on PD following increased EDA FN expression. Methods: Male wild-type (WT) and EDA-FN knockout (KO) mice were randomized to receive saline (Control Group) or glucose-based PD fluid containing 20 mM methylglyoxal (PDF Group) by intra-peritoneal injection twice daily for 12 weeks, after which time the parietal peritoneum was harvested. Total RNA was extracted and subjected to bulk RNA-sequencing. Differentially expressed genes (DEGs) were identified based on |log2(fold change)|>1 and adjusted p<0.05. Enrichment analyses were conducted for GO category genes and KEGG pathways. Results: PDF-treated WT mice developed submesothelial thickening after 12 weeks compared to saline-treated mice. Transcriptomic analysis revealed increased expression of acta2, bgn, col1a1, fn1, lama1, lamb3, lamc3, mmp2, mmp14,snai1 and snai2 in PDF-treated WT mice compared to saline-treated WT mice. Peritoneal membrane thickening was reduced in PDF-treated EDA FN KO mice and was associated with a decrease in genes related to epithelial-to-mesenchymal transition (EMT) and fibrosis, the levels of which were comparable to that detected in saline-treated WT mice. GO and KEGG pathway analyses revealed significant changes in fatty acid metabolism, and AGE-RAGE, MAPK and Rho GTPase signaling pathways. Conclusion: Our data suggest that increased peritoneal EDA-FN expression contributes to peritoneal fibrosis through induction of EMT and alterations in AGE-RAGE and MAPK signaling pathways in PD. Funding: Government Support – Non-U.S.