Direct Observations of Amyloid β Self-Assembly in Live Cells Provide Insights into Differences in the Kinetics of Aβ(1–40) and Aβ(1–42) Aggregation

Abstract

SummaryInsight into how amyloid β (Aβ) aggregation occurs in vivo is vital for understanding the molecular pathways that underlie Alzheimer’s disease and requires new techniques that provide detailed kinetic and mechanistic information. Using noninvasive fluorescence lifetime recordings, we imaged the formation of Aβ(1–40) and Aβ(1–42) aggregates in live cells. For both peptides, the cellular uptake via endocytosis is rapid and spontaneous. They are then retained in lysosomes, where their accumulation leads to aggregation. The kinetics of Aβ(1–42) aggregation are considerably faster than those of Aβ(1–40) and, unlike those of the latter peptide, show no detectable lag phase. We used superresolution fluorescence imaging to examine the resulting aggregates and could observe compact amyloid structures, likely because of spatial confinement within cellular compartments. Taken together, these findings provide clues as to how Aβ aggregation may occur within neurons.

Amyloid β Protein and Alzheimer’s Disease: When Computer Simulations Complement Experimental Studies

“…Compact amyloid aggregates were observed for both alloforms. (486) While, these experiments represent one step ahead towards understanding aggregation in the cells, higher spatial resolution methods and how the cellular environment affects the dynamics of Aβ1-40/42 and their variants are major concerns. To this end, in cell-NMR of Aβ protein is an ideal tool for gaining information at the atomic level, but several obstacles remain.…”

Aβ42 and Aβ40: similarities and differences

“…However, Esbjörner et al . used fluorescence lifetime imaging to monitor amyloid formation in living cells, and they found that both A β 40 and A β 42 were ingested by cell via endocytosis. More researches are required to understand the difference of A β 40 and A β 42 in cellular uptake pathways.…”

A Guide to Structured Illumination TIRF Microscopy at High Speed with Multiple Colors

“…For applications in cell biology and molecular self-assembly reactions [7][8][9][10][11][12] that require imaging with high temporal resolution over many time points, structured illumination microscopy (SIM) can be well-suited as it is not dependent on the photophysical properties of a particular fluorescent probe. Despite this inherent advantage of SIM, up to now its use has been mainly confined to imaging fixed cells or slow moving processes.…”