A team of scientists led by Dr. Thorsten Müller from the Cell Signalling group at the Department of Molecular Biochemistry of the Ruhr University Bochum (RUB) is developing so-called brain organoids from human induced pluripotent stem cells. In the cells, a fluorescence-labelled gene sequence for the expression of the amyloid precursor protein APP was integrated so that the development and further fate of this "Alzheimer's protein" could be closely monitored. Brain organoids are well suited for these more detailed, mechanistic investigations.

While researchers previously believed that the deposits of the APP protein (plaques) is responsible for the development of Alzheimer's, the research team is pursuing a partly different working hypothesis.

They found out that the APP protein in Alzheimer's patients is split twice and breaks down into three parts. The middle parts of several of these cleavages clump together and form the known plaques typical of Alzheimer's outside the nerve cells. However, they do not lead to symptoms instead the researchers concentrated on the split-off part inside the cell.

They observed that this part interacts with another protein and via intermediate steps ultimately leads to this residue migrating into the cell nucleus forming complexes with other residues over time. In cell culture experiments, this led to the death of the nerve cell.

Source:
https://www.mta-dialog.de/artikel/suche-nach-alzheimer-ursachen-im-mini-gehirn.html