- Microvesicles
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Microvesicles (sometimes called exosomes, circulating microvesicles, or microparticles) are fragments of plasma membrane ranging from 50 nm to 1000 nm shed from almost all cell types. Microvesicles play a role in intercellular communication and can deliver mRNA, miRNA, and proteins between cells.[1] They have been implicated in the process of cancer tumor immune suppression, metastasis, tumor-stroma interactions and angiogenesis along with having a role in tissue regeneration.[2][3][4][5] They originate directly from the plasma membrane of the cell and reflect the antigenic content of the cells from which they originate.
Mechanism of shedding of MV
Under physiologic conditions, the plasma membrane of cells has an asymmetric distribution of phospholipids. Aminophospholipids, phosphatidylserine and phosphatidilethanolammine are specifically sequestered in the inner leaflet of the membrane. The transbilayer lipid distribution is under the control of three phospholipidic pumps: an inward-directed pump, or flippase; an outward-directed pump, or floppase; and a lipid scramblase, responsible for non-specific redistribution of lipids across the membrane. After cell stimulation, including apoptosis, a subsequent cytosolic Ca2+ increase promotes the loss of phospholipid asymmetry of the plasma membrane, subsequent phosphatidylserine exposure and a transient phospholipidic imbalance between the external leaflet at the expense of the inner leaflet leading to blebbing of the plasma membrane and microvesicles release.[6]
References
- ^ Balaj, L.; Lessard, R.; Dai, L.; Cho, Y. J.; Pomeroy, S. L.; Breakefield, X. O.; Skog, J. (2011). "Tumour microvesicles contain retrotransposon elements and amplified oncogene sequences". Nature Communications 2 (2): 180. Bibcode 2011NatCo...2E.180B. doi:10.1038/ncomms1180. PMC 3040683. PMID 21285958. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3040683.
- ^ Ratajczak, J.; Miekus, K.; Kucia, M.; Zhang, J.; Reca, R.; Dvorak, P.; Ratajczak, M. Z. (2006). "Embryonic stem cell-derived microvesicles reprogram hematopoietic progenitors: evidence for horizontal transfer of mRNA and protein delivery". Leukemia 20 (5): 847–856. doi:10.1038/sj.leu.2404132. PMID 16453000.
- ^ Hunter, M.; Ismail, N.; Zhang, X.; Aguda, B.; Lee, E.; Yu, L.; Xiao, T.; Schafer, J. et al. (2008). Lo, Yuk Ming Dennis. ed. "Detection of microRNA Expression in Human Peripheral Blood Microvesicles". PloS one 3 (11): e3694. Bibcode 2008PLoSO...3.3694H. doi:10.1371/journal.pone.0003694. PMC 2577891. PMID 19002258. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2577891.
- ^ Aliotta, J.; Pereira, M.; Johnson, K.; De Paz, N.; Dooner, M.; Puente, N.; Ayala, C.; Brilliant, K. et al. (2010). "Microvesicle entry into marrow cells mediates tissue-specific changes in mRNA by direct delivery of mRNA and induction of transcription". Experimental hematology 38 (3): 233–245. doi:10.1016/j.exphem.2010.01.002. PMC 2829939. PMID 20079801. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2829939.
- ^ Castellana, D.; Zobairi, F.; Martinez, M. C.; Panaro, M. A.; Mitolo, V.; Freyssinet, J. -M.; Kunzelmann, C. (2009). "Membrane Microvesicles as Actors in the Establishment of a Favorable Prostatic Tumoral Niche: A Role for Activated Fibroblasts and CX3CL1-CX3CR1 Axis". Cancer Research 69 (3): 785. doi:10.1158/0008-5472.CAN-08-1946. PMID 19155311.
- ^ Hugel, B.; Martinez, M. C.; Kunzelmann, C.; Freyssinet, J. -M. (2005). "Membrane Microparticles: Two Sides of the Coin". Physiology 20: 22–27. doi:10.1152/physiol.00029.2004. PMID 15653836.
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