After pretreatment with an ERK-specific inhibitor, U0126, but not a JNK-specific inhibitor, SP600125, IBD lysates induced increased levels of TGF-β1 in MC38 cells (Supplementary Fig. 6b) and in MC38 cell-derived EVs (MC38-EVs) were totally abolished (Fig. 7c). The gene discussed is MAPK8; the disease is inflammatory bowel disease.