Fidaxomicin Reduces Collagen Expression in Intestinal Fibroblasts Via Platelet-Derived Growth Factor Receptor Beta and Glycogen Synthase Kinase-3 Beta Inhibition

BACKGROUND & AIMS: About 30%-50% of patients with Crohn's disease (CD) eventually develop intestinal strictures, with intestinal fibrosis being a major component of them. There is currently no approved medication to treat fibrotic strictures. METHODS: 10X Genomics Visium spatial RNA sequencing and high-throughput screening were used to discover the molecular targets of intestinal fibrosis. Stricturing Crohn's disease (CDS) patient-derived primary human intestinal fibroblasts (CD-HIFs), stricturing Crohn's disease patient-derived serum exosomes (CDSE), fresh surgically resected whole-thickness ileal tissues, and mouse models of intestinal fibrosis were used. RESULTS: Spatial RNA sequencing found overexpression of platelet-derived growth factor receptor beta (PDGFRB) in the fibrotic ileal tissues of CDS patients. PDGFRB small interfering RNA inhibited collagen expression in the CDSE-treated CD-HIFs. High-throughput screening identified PDGFRB inhibitors that suppressed collagen promoter activity in CDSE-treated CD-HIFs. A machine learning algorithm and molecular docking predicted PDGFR as a target for fidaxomicin. Fidaxomicin, a Food and Drug Administration-approved drug for Clostridioidesdifficile infection, inhibited collagen and PDGFRB messenger RNA (mRNA) expression in CDSE-treated CD-HIFs and CDS patient-derived ileal tissues. CDSE-treated CD-HIFs had increased PDGFRβ and glycogen synthase kinase-3 alpha/beta (GSK3ɑ/β) phosphorylation. Fidaxomicin inhibited PDGFRβ phosphorylation, PDGFRB mRNA expression, and GSK3β phosphorylation in CDSE-treated CD-HIFs. The antifibrogenic effect of fidaxomicin was attenuated by platelet-derived growth factor-BB (PDGF-BB) and insulin-like growth factor 1, which are a PDGFRβ ligand and a GSK3ɑ/β phosphorylation activator, respectively. In the SAMP1/YitFc mice, oral fidaxomicin treatment inhibited ileal fibrosis and ileal PDGFRB mRNA expression and PDGFRβ and GSK3β phosphorylation, which were abolished by Pdgfrb and Gsk3b overexpression. CONCLUSIONS: Fidaxomicin inhibits intestinal fibrosis by reducing PDGFRβ phosphorylation and expression, GSK3β phosphorylation, and collagen expression in intestinal fibroblasts.