Figure 2.

Schematic drawing showing alterations in the exosomal biogenic pathways in DS. Exosomal secretion is increased in individuals with DS, due to a reduced lysosomal/autophagy function and increased levels of the tetraspanin CD63. Endocytosis leads to the accumulation of misfolded Tau (oligomeric and/or fibrillar, red threads) intracellularly into NFTs. Exosomes containing the toxic Tau species can either undergo autophagy or be expelled. It has been shown that exosomes released from neurons can be taken up by other neurons and glial cells in the vicinity. Stars = exosomes; MVB = multivesicular bodies; NFT = neurofibrillary tangles.