Immunofluorescence and immunohistochemistry were performed as previously described (Qi et al., 2017 (link)). Briefly, human intestinal tissues were washed in cold HBSS to remove muscle tissue, fixed with 4% formaldehyde solution for 2 h at 4°C, and dehydrated in 30% sucrose solution at 4°C overnight. Next, the tissue was embedded in optimal cutting temperature compound and stored at −80°C. The sections were prepared with vibrating blade microtome (HM650; Microm) and permeabilized with PBDT solution (3% BSA and 0.1% Triton X-100 in PBS) for 2 h at room temperature. Then, the sections were incubated overnight with the primary antibody at 4°C. The fluorescein-labeled secondary antibodies (1:300; Life Technologies) for immunofluorescence or secondary horseradish peroxidase–conjugated anti-rabbit antibody (1:200; Invitrogen) for immunohistochemistry were added for 2 h at room temperature. Confocal laser scanning (FV3000; Olympus) or 3,3′-diaminobenzidine development (Cytomation; Dako) was used to detect the staining signals.