The tangles, which were first identified in the early 1900s by German psychiatrist and neuropathologist Aloysius Alzheimer, are formed when changes in a protein called tau cause it to aggregate in an insoluble mass in the cytoplasm of cells. Normally, the tau protein is involved in the formation of microtubules, hollow filaments that provide cells with support and structure; abnormal tau tangles, however, cause that structure to break down, and lead to cell death.
Researchers have long puzzled over just what produces the tangles – and, indeed, if they are a cause or a side effect of Alzheimer's and similar neurodegenerative diseases. Now, new research by Eva Chi, an assistant professor of chemical engineering at the University of New Mexico, and her colleagues suggests that changes to the lipid membranes of nerve cells initiate tangle formation.
"Proteins in the brain do not aggregate spontaneously to form amyloid fibrils to cause diseases," says Chi. Rather, she says, "there are physiological triggers that cause these proteins to start aggregating and the lipid membrane may serve such a role." At the AVS Symposium in Nashville, Tenn., held Oct. 30 – Nov. 4, Chi will discuss these tangling triggers and their implications for the development of new Alzheimer's therapies.
Using a combination of techniques, including fluorescence microscopy and X-ray and neutron scattering imaging, Chi and her colleagues found that tau proteins inside nerve cells interact strongly with negatively charged lipids, which are found on the inner surface of cell membranes. "In diseased brains, tau proteins become hyperphosphorylated" – adorned with multiple phosphate (PO43-) groups – "and detach from microtubules. They can then interact with the negatively charged lipids on the cell membrane and start to aggregate into fibrils and cause disease."
When tau proteins interact with the lipid membrane, they can damage the structure of the membrane, "which can possibly make the membranes 'leaky' and cause neurons to die," Chi explains. "There has been much uncertainty about what causes neurodegeneration in these diseases, but now the field is converging on the idea that neuronal death in Alzheimer's disease is caused by the proteins acquiring toxicity as they aggregate."
The researchers suggests that compounds that prevent the proteins from interacting with the lipid membrane – or protect the membrane from being disrupted – could offer hope to Alzheimer's patients. "We are currently looking at how naturally occurring flavonoids [antioxidants found in plants] can protect the cells from protein aggregate-induced toxicity and have found that they reduce protein interaction with membranes," Chi says.
The AVS 58th International Symposium & Exhibition will be held Oct. 30 – Nov. 4 at the Nashville Convention Center.
Presentation NT+AS-WeA8, "Interaction of Alzheimer's Disease Tau Protein with Model Lipid Membranes," is at 4:20 p.m. on Wednesday, Nov. 2.
Main meeting website: http://www2.avs.org/symposium/AVS58/pages/greetings.html
Technical Program: http://www2.avs.org/symposium
Catherine Meyers | EurekAlert!
Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH
Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences