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The cells of the immune system help in learning and memory abilities, and in the regeneration of brain cells

This is the result of a study conducted at the Weizmann Institute

A group of scientists from the Weizmann Institute of Science, led by Prof. Michal Schwartz from the Department of Neurobiology, propose a new concept, according to which the cells of the immune system contribute to maintaining the ability to carry out learning and memory processes, as well as to the regeneration processes of nerve cells in the brain throughout life. This new concept is described in an article published today in the scientific journal "Nature Neuroscience".

For a long time, scientists believed that man was born with a fixed amount of nerve cells in his brain, which gradually die over time and cannot be regenerated. But in recent years, several research groups from different parts of the world have published studies according to which new cells are nevertheless formed in certain areas of the brain, including one of the areas involved in certain processes of learning and memory (hippocampus). This process of creating new nerve cells occurs especially after exposure to an environment rich in environmental stimuli, as well as following physical activity. The function of these new cells is still unclear, but one of the assumptions is that they are designed to preserve and renew the brain's abilities. One of the main questions that remains open is how the body sends signals to the brain instructing it to increase the formation of new cells. Weizmann Institute scientists now offer an explanation for this phenomenon.

The new explanation is based on a new concept of the role of the immune system in the "space of action" of the central nervous system, which includes the brain, the spinal cord and some individual nerves such as the optic nerve. In fact, for many years, the brain was considered a "forbidden city" for the immune system, which was perceived as a factor that could harm the complex and dynamic networks of nerve cells. An even greater danger has been attributed to the presence and activity of autoimmune cells in the brain. These cells (unlike the other cells in the immune system, which attack foreign invaders and disease-causing agents), recognize the body's own components, a process that, if left unchecked, may cause the development of an autoimmune disease, such as multiple sclerosis. Thus, in the past, scientists discovered the presence of autoimmune cells
In a healthy central nervous system, this is attributed to the body's failure to eliminate these unwanted cells. In contrast, the scientists of the Weizmann Institute of Science, led by Prof. Schwartz, believe that autoimmunity in itself is not harmful and even necessary, and that it is a question of "good measure". Uncontrolled autoimmunity can indeed be harmful, but when it exists to the right extent, the same phenomenon itself may actually be beneficial and help delay degenerative diseases such as Parkinson's, Alzheimer's, glaucoma, ALS and neurodegeneration due to stroke, or any damage to the central nervous system.

Prof. Schwartz's research group previously showed that the cells of the immune system (T cells) that recognize components of the central nervous system, regulate the immune response against toxic substances that are secreted in damaged areas, and are involved in neurodegenerative processes. (a known phenomenon in cases of head injuries, as well as after a stroke).

In the current study, the scientists showed that the same immune cells that recognize self-proteins (autoimmune cells) also help in central processes that take place in a healthy brain, such as learning and memory. They hypothesize that this assistance is expressed by encouraging the formation of new brain cells in the hippocampus area that serves to create new memories of certain types. The research group that carried out this study includes, in addition to Prof. Schwartz, the research students Yaniv Ziv, Nega Ron and Oleg Botovsky who worked with the then research student Dr. Yonatan Kipnis, and with Dr. Hagit Cohen from Ben-Gurion University of the Negev.

Several groups of researchers previously reported that in the brain (hippocampus) of rats living in an environment rich in stimuli, more new brain cells are created compared to the amount of new cells created in the brains of rats living in a normal environment. The current study for the first time links this phenomenon to the presence of cells of the immune system in the hippocampus. To examine whether the presence of immune system cells, including T cells, is indeed essential for cell regeneration in the brain, the scientists tested mice with a damaged immune system. It was found that in the brains of these mice, much fewer new nerve cells were formed. In addition, it turns out that when

By injecting T cells taken from a normal mouse into mice with a damaged immune system, it is possible to increase the amount of new nerve cells formed in the brain, almost to the level typical of a healthy mouse. From this, the scientists concluded that T cells are essential for the regeneration processes of nerve cells in the brain, and that repairing the immune system can compensate for this deficiency in the brain.

Another series of experiments was performed with the aim of characterizing the specific T cells that enable the creation of new nerve cells. It was found that in mice genetically engineered so that all the T cells in their body recognize components of the nervous system, more new nerve cells were formed compared to normal mice. These mice also performed better on learning and memory tasks compared to normal mice. Conversely, in mice whose T cells in their bodies do not recognize any components of the nervous system, fewer new nerve cells were formed, similar to mice with a damaged immune system. These mice also had difficulty performing learning and memory tasks.

Prof. Schwartz: "We believe that autoimmune T cells may help the organism realize the full potential of its brain. The findings of our research show that the body transmits messages to the brain, through the immune system, that regulate, among other things, learning and memory abilities. It is also possible that memory loss that occurs at advanced ages is due, at least in part, to the weakening of the immune system, or alternatively to the loss of activity of those cells responsible for brain maintenance. If this is, indeed, the face of things, it is possible that our discoveries may contribute, in the future, to the development of new ways to treat memory loss resulting from aging."

2 תגובות

  1. I wanted to find out if you did an experiment on optic nerve loss due to glaucoma and injected new auto-immune T cells
    And unused optic nerves started to work and vision improved after going blind due to glaucoma?

    My father is a book man who is literally tormented by his lack of sight

    We will do everything to help him see. With God's help

    If you are people from Shura, I would appreciate it if you could send an e-mail
    Thanks in advance
    Rachel

  2. Avi Blizovsky's scientific article, which describes the process of the formation of learning and memory cells as a result of exposure to an environment rich in stimuli as well as physical activity, aligns nicely with Prof. Feuerstein's work with populations with specific learning difficulties. Learning abilities, even damaged ones, can be improved through structured stimuli and an enriching environment. As a veteran teacher working with populations of students with learning difficulties and learning disabilities, I know that the right work improves even limited cognitive abilities.

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