Neutrophil-fibroblast crosstalk drives immunofibrosis in Crohn’s disease through IFNα pathway

Abstract

Crohn’s disease (CD) is characterized by chronic inflammation and intestinal fibrosis leading to lifelong complications. However, disease pathogenesis is elusive and the therapeutic options are limited. We investigated the interaction between neutrophils and intestinal fibroblasts in the development of CD immunofibrosis. Peripheral neutrophils, enriched neutrophil extracellular traps (eNETs), serum, primary intestinal fibroblasts (PIFs) and intestinal biopsies from CD and ulcerative colitis (UC) patients, and healthy individuals (HI), were studied. Neutrophil-targeted transcriptomics, multi-cytokine profiling and cell-based functional assays at mRNA/protein level were performed. Compared to UC, PIFs from CD patients displayed a distinct fibrotic phenotype characterized by negative Krüppel-like Factor-2 (KLF2) and increased cellular communication network factor-2 (CCN2) expression leading to collagen production. In UC and CD, PIFs-derived IL-8 appears as a culprit chemoattractant of neutrophils in the intestine, where CD neutrophils were accumulated close to fibrotic lesions. Functionally, only CD neutrophilsviaeNETs can induce a CD-like phenotype in HI PIFs, suggesting their fibrotic plasticity. High IFNα in serum and IFΝ-responsive signature in peripheral neutrophils were observed in CD, distinguishing it from UC. Moreover, CD serum can stimulate the release of fibrogenic eNETs from neutrophils in an IFNα-dependent manner, suggesting the priming role of IFNα in circulating neutrophils. Inhibition of eNETs or JAK signaling in neutrophils or PIFs prevented the neutrophil-mediated fibrotic effect on PIFs. Furthermore, serum IFNα and transcripts of key IFN-signaling components in neutrophils were well-correlated with CD severity. This study reveals the important role of IFNα/neutrophil/fibroblast axis in CD immunofibrosis, suggesting candidate biomarkers and putative therapeutic targets.