He was also found to have beta-amyloid plaques and tau protein clumps
The aggregation (plaque) of beta-amyloid (Aβ), a toxic protein found in the brains of Alzheimer’s patients, and clumps of tau protein, which is responsible for transporting substances in the nervous system, are also found in chromosomes that cause Down syndrome. , a new study has been published. This is the content reported on the 22nd (local time) by the health medical journal ‘Health Day’ based on a thesis by a researcher at the University of California, San Francisco (UCSF) that was recently published in the Proceedings of the National Academy of the USA. Sciences (PNAS).
Researchers at UCSF’s Weill Neuroscience Institute analyzed brain tissue samples from 28 people who died of Down syndrome and found Aβ plaques and tau tangles in almost all of them. The patients ranged in age from 19 to 65, and the majority died before the age of 40.
Aβ plaques and tau tangles have been analyzed as one of the main symptoms of Alzheimer’s disease. This is related to prions, which are known as protein plague agents. Prion is a compound word of protein and virus particle. Viruses contain nucleic acids such as DNA and RNA and proteins. Prions, which are produced by modifying normal proteins, infect other proteins like viruses without nucleic acids. Prions are produced by excessive accumulation of Aβ in the brain, and have been identified as a causative agent of tau association.
Professor Stanley Pruschner of UCSF, who discovered the prion as research director, said, “Down syndrome and Alzheimer’s disease have completely different causes, but they have been found to cause the same biological phenomenon.” “Because people with Down syndrome show Aβ plaques and tau tangles at a much younger age than people with Alzheimer’s disease, studies of their brains will help us better understand the early stages of disease formation before brain structures become more complicated with age,” he said. “It can help us and provide insight into therapies.”
Down syndrome is caused by three copies of chromosome 21, where there should normally be two. One of the genes on chromosome 21, APP, encodes one of the main components of Aβ. The extra copy of chromosome 21 may shed light on the early formation of Aβ plaques, as it leads to excessive production of APP, the researchers discovered.
The results of this study show that prions are involved in the degeneration of the brain found in Down syndrome, the researchers said. In addition, it was considered that it could be one of the indirect evidence that supports the current theory that excessive accumulation of Aβ causes tau protein entanglement.
“This study confirms the intersection between the two pathologies,” said Carlo Condello, professor of neurology at USCF and first author of the paper. In particular, in the case of Down syndrome, it is explained that he has an extra chromosome that drives Aβ, but it shows that the expression of tau protein increases even though the chromosome does not have a gene related to tau protein.
This also provides new insight into how prions begin to form, he added. “If we can understand how this neurodegeneration begins, we can intervene at a meaningful time and come one step closer to preventing these large brain lesions from forming.”
The paper can be found at the following link (https://www.pnas.org/doi/10.1073/pnas.2212954119).
