MPO and colitis: G-CSF is a crucial regulator of neutrophil differentiation and enhances the bactericidal function of neutrophils, whereas MCP-1 is a necessary component of the inflammatory response required for tissue protection, remodeling, and healthy expansion.30 Mice lacking G-CSF are more susceptible to DSS-induced colitis.31 This would support the weak staining for MPO+ cell infiltration for neutrophils with immunofluorescent staining in the CO diet compared to the other diet groups (Figure S2).