Tatischeff I, Bomsel M, de Paillerets C, Durand H, Geny B, Segretain D, Turpin E, Alfsen A
Laboratoire de Physicochimie Biomoléculaire et Cellulaire, CNRS URA 2056, Université Pierre et Marie Curie, Paris, France.
Cell Mol Life Sci. 1998 May;54(5):476-87. doi: 10.1007/s000180050176.
Dictyostelium discoideum cells are highly resistant to xenobiotics. We previously observed that these primitive eukaryotic cells contain a 170-kDa P-glycoprotein, mediating multidrug resistance in mammalian cells, but nonfunctional in Dictyostelium cells. We show here that D. discoideum cells vitally stained with the DNA-specific dye, Hoechst 33342, release fluorescent material in their culture medium. Electron microscopy and lipid analysis demonstrate the vesicular nature of this material. Moreover, nucleic acids associate with these extracellular vesicles independently of Hoechst vital staining. The main vesicular DNA component exhibits a size > 21 kb. Shedding of microvesicles during cell growth is not concomitant with programmed cell death. We propose that these extracellular vesicles are involved in a new cellular resistance mechanism against xenobiotics. Furthermore, since the association of DNA with vesicles occurs in physiological growth conditions and independently of vital staining, the new shedding process might be involved in a more general intercellular mechanism.
盘基网柄菌细胞对异生物质具有高度抗性。我们之前观察到这些原始真核细胞含有一种170 kDa的P-糖蛋白，该蛋白介导哺乳动物细胞中的多药耐药性，但在盘基网柄菌细胞中无功能。我们在此表明，用DNA特异性染料Hoechst 33342进行活体染色的盘基网柄菌细胞会在其培养基中释放荧光物质。电子显微镜和脂质分析证明了这种物质的囊泡性质。此外，核酸与这些细胞外囊泡的结合独立于Hoechst活体染色。主要的囊泡DNA成分大小> 21 kb。细胞生长过程中微囊泡的脱落与程序性细胞死亡无关。我们提出这些细胞外囊泡参与了一种针对异生物质的新的细胞抗性机制。此外，由于DNA与囊泡的结合发生在生理生长条件下且独立于活体染色，这种新的脱落过程可能参与了一种更普遍的细胞间机制。
