Time Until Neuron Death After Initial Puncture From an Amyloid-Beta Oligomer

TL;DR

This study models the time until neuron death after amyloid-beta oligomer-induced membrane puncture, concluding that cell death occurs within one second of contact, addressing criticisms of previous pore models in Alzheimer's research.

Contribution

We developed a method to estimate neuron death timing after amyloid-beta pore formation, providing a concrete time frame and addressing prior criticisms of pore model assumptions.

Findings

Neuron death occurs within one second after pore contact.

The model challenges the criticism of instant cell death in pore theories.

Identifies potential improvements in pore dynamics and calcium modeling.

Abstract

Hardy and Higgins first proposed the amyloid cascade hypothesis in 1992, stating that the decrease in neuronal function observed in Alzheimer's Disease (AD) is due to a process initiated by the oligomerization of amyloid-beta peptides. One hypothesis states that toxicity arises from the aggregation of amyloid-beta into a pore structure, which can then puncture the brain cell membrane; this allow toxic calcium ions to flood through the opening, causing eventual cell death. In 2007, neurobiologist Ruth Nussinov calculated the three pore sizes most likely to occur within the brain. Based on her findings, we constructed a method to determine the time it takes for a cell to die after the cell is punctured by the pore. Our findings have shown that cell death occurs within one second after the oligomer makes contact with the cell. We believe this is important because instant cell death has been one criticism of Nussinov's model, and we have calculated a concrete time value for that criticism. We identify two potential deficiencies with our model that could be improved: first, we treat the calcium as an ideal gas, which it is not; second, we assume that the pores are static (i.e. constantly open), while recent developments suggest that they may open and close dynamically.