In recent years, researchers have been interested in learning more about the increased risk of Alzheimer’s in diabetics. Well now there is a group of researchers from the City College of New York (CCNY) who have been able to shed some light on the link between diabetes and Alzheimer’s. CCNY biology professor, Chris Li, and some of her colleagues have discovered that there is actually a single gene which forms a common link between the two diseases.
(see also: diabetes clinical trials)
This gene had already been known to be present in many cases of Alzheimer’s, but only recently did they discover that it also affects the insulin pathway. When this pathway is disrupted, it can cause diabetes. This incredible discovery could lead to a new therapeutic target for both diseases. These findings were first reported in the June 2012 issue of Genetics journal.
Research has shown that people who have been diagnosed with type 2 diabetes will have a higher risk of dementia. Professor Li noted that the link is not far-fetched, since the insulin pathways play a role in a number of different metabolic processes. One of the most important of these processes is keeping the nervous system healthy.
Currently, medical researchers are still unsure of exactly what causes Alzheimer’s. One of the ways Alzheimer’s is diagnosed after death is if they find any sticky plaques of amyloid protein present in the decimated portions of the patient’s brain. Mutations in the “amyloid precursor protein” (APP) gene, or in the genes responsible for processing APP, often show up in Alzheimer cases which have affected families. During their clinical study, Professor Li and her colleagues investigated an APL-1 protein, which was made by a gene in the Caenorhabditis elegans (a type of worm). This actually happens to be a perfect substitute for the human Alzheimer’s gene.
Li and her colleagues found that there were mutations which occurred in the worm-equivalent of the APP gene. These mutations caused their development to slow down, which was indicative of a metabolic pathway being disrupted. The researchers then examined exactly how the worm equivalent of APP changed the different metabolic pathways, and they discovered that it was inhibiting the insulin pathway. These results suggested that the APP gene likely plays a part in both diabetes and Alzheimer’s disease. Additionally, they found that added mutations in the insulin pathway caused a reversal of the APP mutation defects. Professor Li stated that this last discovery helped explain the functional link in these genes.
The APL-1 turned out to be very important. In fact, Li noted that if you knock out the worm equivalent of APP, the worm will die. Li went on to explain that the APP family of proteins is just as essential in worms as it is in mammals (that’s you and me!).
Professor Li’s goal is that this crucial new insight will help to redirect research in ways that might lead to more effective therapies in the treatment of both diabetes and Alzheimer’s disease. This new discovery is undoubtedly important, especially given the U.S. government’s new goal to treat Alzheimer’s disease by 2025. This discovery should reveal new options for treating and preventing both diseases, as it has helped to shed light on a most ponderous mystery.
This latest study was able to identify one of the links in the chain, that there is an Alzheimer’s related protein linked to the insulin pathway. This should be able to help researchers learn even more about why type 2 diabetes patients have a higher risk of Alzheimer’s. Unfortunately, there is still much work to be done. This protein actually fragments into many parts, and each fragment has the ability to attach to and signal other cells and neutrons. According to professor Li, the next biggest question is, “how the amyloid precursor protein and its cleavage products intersect with the insulin pathway.”
This clinical study was funded by the Alzheimer’s Association, the National Institute of Health (NIH), and the National Science Foundation (NSF). Professor Li has stated her intent to continue conducting more research on this topic, and she knows that each new insight offers new targets for medication and other treatments.