How are exosomes formed?

Exosomes are of endocytic origin. Their formation begins inside the cell, where certain structures called endosomes capture and engulf specific molecules and cellular components. These endosomes then mature and transform into multivesicular bodies (MVBs).

Inside the MVBs, the endosomes develop small pouches or vesicles within them, called intraluminal vesicles (ILVs). These ILVs contain various molecules, including proteins, RNA, and lipids.

Eventually, the MVBs can take one of two paths - they can fuse with the cell's membrane and release their contents outside the cell, or they can be targeted to a specific destination within the cell.

When MVBs fuse with the cell's outer membrane, the ILVs inside are released into the extracellular space, becoming exosomes. These exosomes can then travel through the body, carrying their cargo of molecules to other cells, where they can be taken up and affect cellular processes.