Can a person live many times longer and not get cancer - scientists hope to find out by studying naked mole rats, unsightly rodents from Africa. Vadim Gladyshev, a renowned geneticist from Moscow State University and Harvard, explains what these "immortal" creatures can and cannot, and also what we can learn from them.
Stop time
The naked mole rat (Heterocephalus glaber) is a unique mammal with many amazing properties. This hairless underground rodent is about the size of a mouse and weighs 30-50 grams, native to East Africa.
In the 1970s, scientists discovered that these creatures live unusually long lives for their size, ten times their normal size. They later found out that they are almost immune to cancer. In addition, mole rats do not feel some types of pain. For example, they do not react to skin irritation upon contact with acids.
Their main unusual feature is that they violate the so-called Gompertz distribution - a pattern according to which the probability of death increases exponentially with age. For example, for a person, the chances of dying double every eight years.
Naked mole rats, as recent observations of biologists from the United States show, die equally rarely at an early age, and at 20-30 years, already many times exceeding the lifespan for rodents of this size.
Gladyshev and his colleagues have been trying to uncover the secret of these unusual animals for a long time. Back in 2011, they decoded the genome of Heterocephalus glaber, and two years later discovered some of the mechanisms responsible for cancer immunity and longevity.
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For example, two other Russian excavator specialists, Vera Gorbunova and Andrei Seluyanov of the University of Rochester, are engaged in similar experiments.
Recently, they and Gladyshev tested the hypothesis that the cells of mole rats are not subject to aging. Biologists believed that cells in these animals can divide indefinitely, and not 40-50 times, as in humans and other mammals.
Having reached this limit, the cells of humans and other "mortals" transfer themselves to a special regime, stop dividing and participate in the life of the organism. This prevents the formation of cancerous tumors in the body, but the accumulation of such cells leads to decrepitude, old age.
There are other forms of cellular aging, when a cell "retires" for very different reasons - as a result of fatal DNA damage, during the development of tissues of the embryo, or when the level of cellular stress is too high. All this, as was previously believed, is not typical of naked mole rats.
Russian-American biologists have shown that this is not so: the cells of mole rats are susceptible to all three types of cellular aging.
At the same time, they resisted the action of both oncogenes and gamma rays unusually well in comparison with similar samples of mouse tissues.
End of eternity
These experiments are already under way with the participation of Russian specialists working in Russia and leading American research centers. As Gorbunova said, speaking at Moscow State University at the Frontiers in Aging conference organized by Gladyshev, they recently conducted the first experiment on transplanting Heterocephalus glaber genes into the genome of mice.
One of these DNA regions, which is responsible for the "adhesion" of cells to each other, significantly extended the life of rodents. They lived several weeks longer than normal mice, which is equivalent to ten years for humans.
This longevity was also due to the fact that such transgenic mice suffered from tumors about half as often as their relatives from the control group. This, however, did not end with the positive effect of such gene therapy.
As shown by observations of mice, their body had significantly more "adult" stem cells, they were much less likely to suffer from osteoporosis, problems with lungs and other senile diseases. In addition, these rodents were more resilient and stronger than their older counterparts.
The successful completion of such experiments makes many people think about whether there is a hard limit on life expectancy set from above by evolution, whether it can be overcome, and whether it is worth doing at all.
According to the Harvard geneticist, the truth is most likely somewhere in between. The number of centenarians in recent years has been growing at about the same rate, without slowing down, but the age at which the oldest people die each year is increasing extremely slowly.
The moral of immortality
Such results of experiments, according to Gladyshev, indicate that at the limit of life it is not a rigid, but a mobile character - it can be overcome, but the price of each step will grow rapidly. In addition, editing the human genome is not only technically difficult, but often such experiments raise ethical questions.
If scientists find harmful mutations associated with aging, it will be possible to prolong life with gene therapy. How to use it, where the border between the fight against disease and aging and "human improvement", according to Gladyshev, must be decided by society.
The prospect of a significant increase in human life expectancy with the help of diggers and other long-lived creatures makes philosophers and psychologists wonder how a long or potentially infinite life will affect a person. Will people become more human or cruel, and what will society be like?
