Figure 1.

Formation of exosomes and functions/mechanisms of exosomes in IBD. Exosomes are formed by inward budding of cell membrane and are released through fusion of multi-vesicular body (MVB) with the membrane. MVB can be degraded by fusion with lysosome and losing the activity of components inside. Golgi apparatus in origin cells can accumulate some exosomal proteins before their secreting into the exosomes. The effects of secreted exosomes on IBD includes ➀ the exosomes isolated from serum and saliva may be novel biomarkers of IBD; ➁ Exosomes from colon cancer cells, IECs, and platelets, can maintain TJ barrier function; ➂ Exosomes from DCs may influence intestinal microbiota profile in heat shock proteins dependent manner; ➃ Intestinal epithelial cell (IEC)-derived exosomes can fuse with the membrane of dendritic cells (DCs) to induce immune tolerance; ➄ Exosomes from colitis serum or treated DCs regulates immune cell proliferation through MAPK, NF-κB, and other inflammation related signaling pathways.