Fragments of RNA age neurons
The mechanism of irreversible aging of the brain is revealed
Biologists at the Massachusetts Institute of Technology (USA) have found out that with age, short fragments of RNA accumulate in some neurons, which are formed during oxidative stress. This process leads to irreversible changes in the brain. The study is reported in a press release Biologists discover an unusual hallmark of aging in neurons
According to scientists, the accumulation of short-stranded RNA molecules is a marker of neurodegenerative diseases, the risk of which increases with age. It also helps to reduce the amount of synthesized proteins important for the functions of the central nervous system. This phenomenon has been observed in both mouse and human brains, including an area called the striatum (striatum). This anatomical structure is responsible for muscle function and is associated with Parkinson's and Huntington's diseases.
The neurons of 19-month-old mice (bottom row) show much higher levels of oxidative stress than the neurons of 9-week-old mice (top row). Lipofuscin, a molecule associated with age–related oxidative stress, is marked in red - VM.
There are various types of RNA, including matrix RNA (mRNA). mRNA performs the function of transferring genetic information from DNA to ribosomes, which build protein chains in accordance with the sequences of nucleotides in RNA. The scientists analyzed the RNA in the projection spiked neurons D1 and D2 in young and old mice. This type of neuron accounts for 95 percent of all striatum neurons.
It turned out that in D1 neurons in old animals, about 400 genes produce only short fragments of mRNA, called 3'-untranslated regions. They were attached to ribosomes, preventing the synthesis of the right proteins. The cause of the failure is oxidative stress caused by increased formation of reactive oxygen species in neurons. The radicals react with the active center of the enzyme ABCE1, which separates mRNA from ribosomes after protein synthesis is completed.
Scientists have also discovered a similar process in human brain tissues, including the frontal lobe of the cerebral cortex.
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