Fauré J, Lachenal G, Court M, Hirrlinger J, Chatellard-Causse C, Blot B, Grange J, Schoehn G, Goldberg Y, Boyer V, Kirchhoff F, Raposo G, Garin J, Sadoul R
Laboratoire Neurodégénérescence et Plasticité, INSERM-Université Joseph Fourier, Pavillon de Neurologie, Hopital A. Michallon, BP 217, 38043 Grenoble Cedex 9, France.
Mol Cell Neurosci. 2006 Apr;31(4):642-8. doi: 10.1016/j.mcn.2005.12.003. Epub 2006 Jan 30.
Accumulating evidence shows that several cell types have the capacity to secrete membrane proteins by incorporating them into exosomes, which are small lipid vesicles derived from the intralumenal membranes of multivesicular bodies (MVBs) of the endocytic pathway. Exosomes are expelled in the extracellular space upon fusion of the MVB with the plasma membrane. Exosomal release is a way of secreting membrane proteins meant to be discarded, or to be passed on to other cells. Here, we demonstrate, using primary cortical cultures, that neurones and astrocytes can secrete exosomes. We find that exosomes released by cortical neurones contain the L1 cell adhesion molecule, the GPI-anchored prion protein, and the GluR2/3 but not the NR1 subunits of glutamate receptors. We also show that exosomal release is regulated by depolarisation. Our observation suggests that exosomes may have a regulatory function at synapses and could also allow intercellular exchange of membrane proteins within the brain.
越来越多的证据表明，几种细胞类型能够通过将膜蛋白整合到外泌体中来分泌膜蛋白，外泌体是源自内吞途径多泡体（MVB）内腔膜的小脂质囊泡。当MVB与质膜融合时，外泌体被排出到细胞外空间。外泌体释放是一种分泌膜蛋白的方式，这些膜蛋白要么被丢弃，要么传递给其他细胞。在这里，我们使用原代皮质培养物证明，神经元和星形胶质细胞可以分泌外泌体。我们发现皮质神经元释放的外泌体含有L1细胞粘附分子、糖基磷脂酰肌醇锚定的朊病毒蛋白以及谷氨酸受体的GluR2/3亚基，但不含有NR1亚基。我们还表明，外泌体释放受去极化调节。我们的观察结果表明，外泌体可能在突触处具有调节功能，并且还可能允许大脑内细胞间膜蛋白的交换。
