Authors: Erica Lana Mahbod Khanbolouki Charline Degavre EvaBritt Samuelsson Elisabet Åkesson Bengt Winblad Evren Alici Christina Unger Lithner Homira Behbahani
Publish Date: 2016/01/16
Volume: 54, Issue: 2, Pages: 874-887
Abstract
Studies on the mechanisms of neuronal amyloidβ Aβ internalisation are crucial for understanding the neuropathological progression of Alzheimer’s disease AD We here investigated how extracellular Aβ peptides are internalised and focused on three different pathways i via endocytic mechanisms ii via the receptor for advanced glycation end products RAGE and iii via the poreforming protein perforin Both Aβ40 and Aβ42 were internalised in retinoic acid differentiated neuroblastoma RASHSY5Y cells A higher concentration was required for Aβ40 250 nM compared with Aβ42 100 nM The internalised Aβ40 showed a dotlike pattern of distribution whereas Aβ42 accumulated in larger and distinct formations By confocal microscopy we showed that Aβ40 and Aβ42 colocalised with mitochondria endoplasmic reticulum ER and lysosomes Aβ treatment of human primary cortical neurons hPCN confirmed our findings in RASHSY5Y cells but hPCN were less sensitive to Aβ therefore a 20 Aβ40 and 50 Aβ42 times higher concentration was needed for inducing uptake The blocking of endocytosis completely inhibited the internalisation of Aβ peptides in RASHSY5Y cells and hPCN indicating that this is a major pathway by which Aβ enters the cells In addition the internalisation of Aβ42 but not Aβ40 was reduced by 55 by blocking RAGE Finally for the first time we showed that pore formation in cell membranes by perforin led to Aβ internalisation in hPCN Understanding how Aβ is internalised sheds light on the pathological role of Aβ and provides further ideas of inhibitory strategies for preventing Aβ internalisation and the spreading of neurodegeneration in ADThis research was founded by grants from Gun and Bertil Stohne’s Foundation Alzheimer Foundation Olle Engkvist Byggmästare Foundation OE and Edla Johansson’s Scientific Foundation Sigurd and Elsa Golje’s Memorial Foundation Foundation for Old Servants Tore Nilson’s Foundation for Medical Research Dementia Association Karolinska Institutet Foundations and Sheikha Salama bint Hamdan Al Nahyan Foundation Abu Dhabi The authors would like to thank Dr Lars O Tjernberg for the critical reading of this manuscript
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