Exosomes

EXOSOMES ARE THE IDEAL TOOLS FOR BIO-DRUGS

TRIGGER HIGH IMMUNE RESPONSES

CROSS ALL BARRIERS

These nano-vesicles are produced naturally by the cells. Long regarded as simple cell cleaners, they have acquired a major attraction for 10 years with the progressive understanding of their properties :

They have natural immunostimulatory properties leading to high immune responses
They are “intercellular membrane messengers” required to the proper functioning of the body
They are biocompatible without any toxicity
They perfectly mimic a virus in size and shape
They can cross all the barriers of the body including the blood brain barrier
They transfer various types of information or signals via different molecules (RNA, proteins, lipids, small molecules) between cells

KNOWLEDGE ABOUT EXOSOMES

MEMBRANE NANO-VESICLES

Exosomes are membrane vesicles of 50 to 150 nm in diameter, secreted by a wide range of eucaryotic cell types. They come from late endosomes called MultiVesicular Bodies (MVB) that contain intraluminal nano-vesicles. Upon fusion with the plasma membrane, the intraluminal nano-vesicles are released in the extracellular environment and become exosomes. Exosomes can fuse back to plasma and/or endosomal membranes.

Exosomes contain membrane proteins, cytosolic proteins and different RNAs (miRNAs, mRNAs…). A growing body of evidence reveals that exosomes are intercellular vehicles that serve as mediators able to reprogram the target cells through the delivery of cargo (proteins and RNAs). They cross all the body barriers, including the blood brain barrier.

GREAT IMMUNOSTIMULATORY POTENTIAL

There is strong evidence that exosomes are potent modulators of immune information in an inhibitory or stimulating manner. In the presence of immunogens, the activated dendritic cells produce exosomes that transmit the immune information to the T cells. Consequently, the exosomes can trigger cellular and/or humoral immune responses that result in tumor regression or protection against pathogens.

STILL A LOT TO DISCOVER

The molecular mechanisms of exosome secretion and protein sorting in exosomes are not yet fully understood. Indeed, several types of extracellular vesicles (EVs) exist, differing in their origin and/or function. It has been reported that the budding of vesicles in MVB could be triggered by sphingolipid ceramide, but several reports showed also that ESCRT machinery is at work in vesicle budding and EV secretion.