In 2016, Bosma et al. first discovered that [2] FNDC4 can be cleaved and secreted as the extracellular N-terminal fibronectin type III domain (sFNDC4), which plays an anti-inflammatory role in inflammatory bowel disease (IBD) by affecting macrophage phagocytosis, survival, cytokine secretion, and cell polarization. Here, FN1 is linked to inflammatory bowel disease.