Comprehensive coverage

Inventory count of senescent cells

Removing aging cells from the body may prevent disease and possibly even prolong life. Scientists from the Weizmann Institute have developed a method to count these cells

Senescent cells (top) and normal cells (bottom) from the inner lining of a mouse lung, stained with colors that highlight the markers of aging (left) or the characteristics of the lining (right). Filmed with ImageStreamX technology. Source: Weizmann Institute magazine.
Senescent cells (top) and normal cells (bottom) from the inner lining of a mouse lung, stained with colors that highlight the markers of aging (left) or the characteristics of the lining (right). Filmed with ImageStreamX technology. Source: Weizmann Institute magazine.

The human body contains aging cells that resemble the walking dead: they no longer divide, but refuse to end their journey. Studies have revealed that LAging cells These (senescent cells) actually have a role in wound healing and protection against cancer, but as we grow older, they accumulate in organs and may cause more harm than good - including diseases such as osteoarthritis or arteriosclerosis. Recent studies in mice indicate that eliminating aging cells from the body may prevent diseases related to old age and may even prolong life.

"If you want to kill aging cells in order to prevent or cure diseases, it is important to know, first of all, how many such cells this or that tissue contains," says Prof. Valery Kryzhnovsky From the Department of Molecular Biology of the Cell at the Weizmann Institute. Together with the members of his group, he developed a method that allows counting senescent cells in mice. The method may make it possible to develop in the future ways to count these cells in humans, as well as help determine at what age these cells begin to accumulate and the degree of success of treatments designed to remove them from the body. This research was recently published in the scientific journal aging cell.

Prof. Krizhnovsky and his colleagues managed to count Aging cells in mouse tissue using a combination of two methods: the first, tissue staining in order to highlight a desired cellular or molecular characteristic - in this case, characteristics that can be used to identify an aging cell. The second, flow cytometry - which was implemented in collaboration with Dr Ziv PoratFrom the Department of Life Science Research Infrastructures - allows the cells to be counted after detection in the solution and the creation of their high-resolution images. Using this combined approach, the scientists discovered that in the tissues of two-month-old mice, the concentration of senescent cells was less than 1%, while in two-year-old mice, the concentration in certain organs jumped up to 15%. "In the old mice, the concentration was many times higher than we expected," says Prof. Krzyznovsky.

"If you want to kill aging cells in order to prevent or cure diseases, it is important to know, first of all, how many such cells this or that tissue contains"

From the right: Prof. Valery Krizhnovsky, Dr. Hila Gal, Lior Roitman and Dr. Yosef Ovadia. Source: Weizmann Institute magazine.
From the right: Prof. Valery Krizhnovsky, Dr. Hila Gal, Lior Roitman and Dr. Yosef Ovadia. Source: Weizmann Institute magazine.

Cells race to their death

Another surprise awaited scientists in another study, which Recently published in the scientific journal The EMBO Journal. In this study, Prof. Krzychnovsky and his colleagues focused on one of the mechanisms that cause cells to become "walking dead". This mechanism consists of a chain of molecular reactions in which the p21 gene functions as a "brake" that prevents cells from dividing after their DNA is damaged. This gene is activated, among others, by the p53 gene, known as the "guardian of the genome" and known for its role in suppressing cancer tumors. Thus, it has been suggested that p21 is also a tumor suppressor. However, if this were the case, it would be possible to find mutant copies of it in cancer tumors, but these mutations were found only rarely in the cancer genome reviews.

Prof. Krzyznowski and his group set out to discover exactly how p21 causes cells to remain in senescence. They reduced its activity in aging cells and expected that as a result the cells would begin to divide again. But right here a surprise awaited them: instead of multiplying, the aging cells died.

Without sufficient activity of p21 the cells apparently entered a kind of spiral: their DNA quickly absorbed more and more damage that eventually led to their death. "When we released the 'brake', the cells simply raced forward to their death," says Prof. Krzyznowski.

Later, the scientists investigated the involvement of p21 in liver fibrosis - a disease in which aging cells accumulate in the liver and participate in the production of scar tissue. They studied the course of the disease in mice and found that in those lacking the p21 gene, the amount of senescent cells in the liver was smaller than in normal mice and there was an improvement in their fibrosis markers. These results indicate that in the future it may be possible to remove aging cells from the body with the help of silencing the p21 gene, thus helping to maintain the health of the tissues and prevent deterioration in their condition associated with old age.

The research group included Dr. Hila Gal, Dr. Anat Biran, Dr. Reot Yosef, Dr. Noam Falfel, Dr. Yosef Ovadia, Nurit Papismedov, Lior Reutman, Lior Zada, Pula Abu Kerem, Stav Miller and Ezra Vaday from the Department of Molecular Biology of the Cell; and Dr. Shipra Ben Dor from the Department of Life Sciences Research Infrastructures.

#Science_Numbers

The number of senescent cells in finite tissues is about 15 times greater in old mice compared to young ones

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.