library_construction_protocol: Tissues were incubated in buffered EGTA at 37 Celsius for 15 minutes to separate epithelium from lamina propria. Epithelium was digested in TrypLE express at 37 Celsius for 5 minutes. Lamina propria was digested in liberase TM at 37 Celsius for 20 minutes. Amplication product of cDNA was processed with Dnase fragmentation, A tailling, ligation of adaptors and index PCR per 10x Genomics 3'RNA v3.1 library construction protocol.