HIF1A and colitis: As the gut mucosa is characterized by low oxygen viability at steady state, HIF-1α is commonly active in intestinal epithelial and LP cells.5,7 The absence of HIF-1α in the intestinal epithelium aggravates colitis and impairs the epithelial barrier.41,44 However, the cell type – specific expression of HIF-1α has been shown to play distinct functions, mainly in the innate compartment.