Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study links Alzheimer’s disease to abnormal cell division

18.01.2006


A new study in mice suggests that Alzheimer’s disease (AD) may be triggered when adult neurons try to divide. The finding helps researchers understand what goes wrong in the disease and may lead to new ways of treating it. The study was funded in part by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health, and appears in the January 18, 2006 issue of The Journal of Neuroscience.*



For unknown reasons, nerve cells (neurons) affected by AD and many other neurodegenerative diseases often start to divide before they die. The new study shows that, in animal models of AD, this abnormal cell division starts long before amyloid plaques or other markers of the disease appear. Cell division occurs through a process called the cell cycle. "If you could stop cell cycling, you might be able to stop neurons from dying prematurely. This could be a fresh approach to therapy for Alzheimer’s and other diseases, including stroke, amyotrophic lateral sclerosis [also known as Lou Gehrig’s disease], and HIV dementia," says Karl Herrup, Ph.D., of Case Western Reserve University in Cleveland, who led the study.

The researchers compared the brains of three different mouse models of AD to brains from normal mice, looking specifically for markers of cell cycling. They found that, in the AD mouse models, cell cycle-related proteins appeared in neurons 6 months before the first amyloid plaques or disease-related immune reactions developed in the brain. Many of the neurons also had increased numbers of chromosomes, which is typical of cells that have begun to divide. These changes were not seen in normal mice. The regions of the brain most affected by the neuronal cell cycling were the cortex and the hippocampus – the same regions most affected in AD. The cortex is important for thought and reasoning, while the hippocampus plays a key role in learning and memory. Some parts of the brainstem also showed evidence of cell cycling.


While the cell cycling appeared to be necessary for neurons to die, it was not an immediate cause of cell death in the mouse models of AD. Instead, the affected neurons appeared to live for many months in a near-functional state, with the mice showing only mild behavioral changes during that time. This suggests that another type of cellular problem, still unidentified, must damage the neurons in order for them to die.

The findings shed new light on the theory that the accumulation of amyloid beta in the brain causes the neuron death in AD. Because the abnormal cell cycling begins months before the formation of amyloid plaques, it is unlikely that the plaques themselves trigger the disease process. However, tiny clumps made up of several amyloid beta molecules (called micro-molecular aggregates) form before the plaques and may trigger the disease. Since the three mouse models tested in this study all had mutations in the gene that codes for amyloid precursor protein, the similarity between affected brain regions in these mice and in people with AD also supports the amyloid hypothesis.

While previous studies have linked AD to abnormal cell cycling, this is the first study to examine the link using standard mouse models of AD. The results indicate that the mice, which do not develop neurofibrillary tangles or the severe behavioral symptoms of AD, are accurate models of the early cellular processes that lead to the disease. "The cell cycle markers mimic the human situation rather well," says Dr. Herrup. "This opens a range of new experimental possibilities using the cell cycle events as indicators of neuronal distress."

Dr. Herrup and his colleagues are now trying to determine if feeding the mouse models the drug ibuprofen can stop abnormal cell cycling in neurons and halt neurodegeneration. Ibuprofen is an anti-inflammatory drug that reduces production of amyloid beta, and some studies have suggested that it may reduce the risk of AD. The researchers are also planning additional studies to identify why neurons start to divide when they are diseased and why entering the cell cycle appears to trigger cell death.

Natalie Frazin | EurekAlert!
Further information:
http://www.ninds.nih.gov/

More articles from Studies and Analyses:

nachricht Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>