Exosome-like vesicles derived by Schistosoma japonicum adult worms mediates M1 type immune- activity of macrophage
【摘要】：Background: Exosomes play an important role in intercellular signaling and exert regulatory function by carrying bioactive molecules. As numerous pathogens, adult worm of Schistosoma japonicum(S. japonicum) resides in mesenteric veins of definitive host including man and mammal animals. It was reported that the worms or the eggs also has specialize secretion systems to export effecter proteins or other molecules into host target cells. However, the mechanisms involved remained unclear. This study investigated the isolation of the exosome-like vesicles secreted by Schistosoma japonicum adult worms and its immune- activity on microphage in vitro. Methods AND Results: Exosomes are 30–100 nm membrane vesicles of endocytic origin that are released into the extracellular space upon fusion of the multi-vesicular bodies(MVB) with the plasma membrane. While initial studies described that the role of exosomes was a reticulocyte cargo-disposal mechanism allowing remodeling of the plasma membrane during the maturation of reticulocytes to erythrocytes. Recent studies indicate that exosomes are secreted by most cells and pathogens; which contain protein, nucleic acid and lipid and involved in cell– cell communication, modulating immune responses, transfer virulence factors. In this report, we identified exosome-based secretion as a new mechanism for protein secretion by S. japonicum. Electron microscopy tomography revealed the previously unidentified ultrastructural detail of exosome-like vesicles with high resolution. Exosome-like vesicles were found to be typical spherical shape and to have a diverse population that varies in size of 30–100 nm. Exosome-like vesicles isolated from S. japonicum contained a significantly different protein compare with debris pelleted and the apoptosis body. We also demonstrate that macrophages were preferentially differentiated into the M1 subtype while treated with S. japonicum exosome-like vesicles.Conclusions: This study reveals there are exosome-like vesicles derived by Schistosoma japonicum adult worms, and the exosome-like vesicles can mediates M1 type immune- activity of macrophage.