Exosome

B cells also have impact on T-cell differentiation. B-cell antigen presentation plays an important role at promoting Th2 responses and pathophysiology during allergic disorders. It has been shown that B-cell -/- mice and in mice selectively deficient in MHCII on B cells had decreased Th2 cytokines IL-4 and IL-5 [152]. Also in another study it has been reported that B-cell-derived exosomes can present allergen peptides and activate allergen-specific T cells to proliferate and produce Th2 cytokines IL-5 and IL-13 [42]. 

Valenta R, Scheynius A, Gabrielsson S B-cell- SS derived exosomes can present allergen peptides and activate allergen-specific X cells to prohferate and Sb produce Tjj2-like cytokines. J Allergy Chn Immunol 2007 120 1418-1424. 

Goyal A, GH Delves GH, M Chopra, BA Lwaleed, and AJ Cooper. 2006b. Prostate cells exposed to lycopene in vitro liberate lycopene-enriched exosomes. BJU Int 98(4) 907—911. 

Mukherjee, D., Gao, M., O Connor, J. P., Raijmakers, R., Pruijn, G., Lutz, C. S., and Wilusz, J. (2002). The mammalian exosome mediates the efficient degradation of mRNAs that contain AU-rich elements. EMBO J. 21, 165-174. 

Wang, Z., and Kiledjian, M. (2001). Functional link between the mammalian exosome and mRNA decapping. Cell 107, 751-762. 

Simons M, Raposo G (2009) Exosomes-vesicular carriers for intercellular communication. Curr Opin Cell Biol 21 575-581... 

Jacobs, J. S., Anderson, A. R., and Parker, R. P. (1998) The 3 to 5 degradation of yeast mRNAs is a general mechanism for mRNA turnover that requires the SKI2 DEVH box protein and 3 to 5 exonucleases of the exosome complex. EMBO J. 17, 1497-1506. 

MICROVESICLES A NOVEL SOURCE OF BIOMARKERS 6.1 Metabolomics in Exosomes Research... 

Exosomes are membranous vesicles 40-100 nm sized, released by cells in different extracellular fluids. Blood exosomes, despite being previously considered inert debris without specific function, have been demonstrated to be important in the regulation of different mechanisms in vascular pathologies... 

By LC-MS/MS, lysophosphatidylethanolamine has been tentatively associated with a renal cell carcinoma signature in urinary exosomes, although further validation in wider and independent cohort of samples is yet pendant... 

Although studies focused on the alterations at the metabolome level in exosomes are scarce, there is enough evidence to prove their potential role as key messengers of organism disturbances, which will nicely translate into a more accessible fluid (i.e., urine) those changes occurring at tissue (i.e., kidney) level. 

Cell-Derived Microparticles and Exosomes in Neuroinflammatory Disorders... 

Dendritic cell-derived exosomes DNA fragmentation factor... 

Exosome A precise definition is a work in process, but an exosome can be considered... 

Such microvesicles have size variable between 50 nm to 1 (xm and differ from other vesicles (like exosomes (30-100 nm)). In general, microparticles are phospholipids vesicles derived from eukaryotic cells as a result of different types of stimulation. Microparticles can also be defined as phospholipids microvesicles containing certain membrane proteins originating from the parental cell. Microparticles circulate in the blood and contribute to numerous physiological processes. MPs have been described in various haematopoietic cells as platelets (Heijnen et al. 1999), T-cells (Blanchard et al. 2002), polynuclear neutrophils (Mesri and Altieri 1999) or dendritic cells. After have been considered as cell dust, MPs are now considered to reflect cell activation. Platelet derived microparticles have been the most extensively studied until now. They are now accepted to play an important role in the procoagulant... 

Blanchard, N., Lankar, D., Faure, F., Regnault, A., Dumont, C., Raposo, G. and Hivroz, C. (2002) TCR activation of human T cells induces the production of exosomes bearing the TCR/CD3/zeta complex. J. Immunol. 168, 3235-3241. 

Heijnen, H.F., SchiefA.E., Fijnheer, R., Geuze, H.J. and Sixma, J.J. (1999)Activatedplatelets release two types of membrane vesicles microvesicles by surface shedding and exosomes derived from exocytosis of multivesicular bodies and alpha-granules. Blood 94, 3791-3799. 

Thery, C., Boussac, M., Veron, P., Ricciardi-Castagnoli, P., Raposo, G., Garin, J. and Amigorena, S. (2001) Proteomic analysis of dendritic cell-derived exosomes a secreted subcellular compartment distinct from apoptotic vesicles. J. Immunol. 166, 7309—7318. 

Wubbolts, R., Leckie, R.S., Veenhuizen, P.T., Schwarzmann, G., Mobius, W., Hoemschemeyer, J., Slot, J.W., Geuze, H.J. and Stoorvogel, W. (2003) Proteomic and biochemical analyses of human B cell-derived exosomes. Potential implications for their function and multivesicular body formation. J. Biol. Chem. 278,10963-10972. 

Historically, the word exosome, (beside designating the multienzyme ribonuclease complex identified in S, cerevisiae), has been used to define different types of vesicles released by cells (Figure 1). We feel it is critical to differentiate between the various kinds of vesicles since their mode of biogenesis could be directly related to their physiologic function and/or to the state of the productive cell. 

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