Is premature aging curable?
Mice treat children from old age
Scientists have managed to cope with the phenomenon of premature aging,
by turning off just one enzyme
Grigory Kolpakov, Newspaper.
A way has been found to defeat progeria – premature aging. So far, experiments are being conducted only on mice, but there is hope that children who live their lives too quickly can be cured by turning off just one enzyme. Studies of this disease and methods of combating it can become the basis for solving the problem of normal aging in humans.
Progeria is a rare disease, also known as Hutchison–Guilford progeric syndrome, which is caused by a sporadic mutation of just one gene. Sporadic mutations are called, which are not inherited from the parents to the child, but occur during the maturation of germ cells or during the development of the embryo.
Progeria is a genetic disease, but not hereditary. The guilty Imna gene encodes a protein called "prelamin A", from which the shell of the cell nucleus is formed. Prelamin A, created according to the patterns of the mutant gene, makes this shell imperfect, which leads to a change in the structure of the nucleus, instability of the genome and disruption of gene expression. Children with progeria quickly go bald, their skin ages, and their bones become brittle. At the age of six, they look old, and at about thirteen they die of a stroke or heart attack due to severe atherosclerosis.
This, in fact, explains the sporadic nature of the mutation: patients with childhood progeria simply do not have time to live to reproductive age and pass on the defect by inheritance.
A group of Swedish biologists from Gothenburg, led by Professor Martin Berge, after years of research, found a way, if not to repair the mutant protein, then at least to disarm it, deprive it of the ability to age the body. The researchers described their method tested on mice in an article published in the latest issue of the journal Science (Ibrahim et al., Targeting Isoprenylcysteine Methylation Ameliorates Disease in a Mouse Model of Progeria). They found that the main troubles with the mutant protein begin to occur after an enzyme called ICMT attaches a small chemical group to one of its ends. This does not happen if the ICMT action is blocked. To test this, a group of biologists from Singapore, collaborating with the Gothenburg team, has developed a potential inhibitor (blocker) of ICMT.
The scientists worked on a mouse model of progeria: genetically modified mice that carried the mutant gene aged prematurely in the same way as humans. "When we used this drug to reduce the production of the enzyme in mice with the mutant Imna gene," says Professor Berge, "all the clinical symptoms of progeria in them either significantly weakened or disappeared altogether.
We also examined cell cultures taken from children with progeria, and found that when the enzyme is suppressed, the cells begin to grow faster, just as it happened with mouse cell cultures, and in both cases the mechanism of the process was the same.
This, of course, does not mean that the medicine developed in Singapore can be used to treat children with progeria tomorrow. According to Berge, so far studies are conducted only on mice.
As already mentioned, Hutchison–Guilford syndrome is not just a rare, but a rare disease. Now only about a hundred children suffer from it all over the world.
Of course, it will be a great happiness for their parents to save the little old people from a terrible fate, but this is not the only reason for the extraordinary interest shown in research in the scientific community.
"The reason for this interest is obvious," says Professor Berge. – This is an extraordinary similarity between the course of the normal aging process and accelerated aging in children with progeria, which means that progeria can clarify many secrets of normal aging. Children develop osteoporosis, muscle weakness, myocardial infarction, stroke – everything is like old people, but they never have cancer or dementia."
Continuing experiments on mice, Berge's group is now investigating the effect of the ICMT inhibitor on normal mice for this very purpose – to deal not only with accelerated, but also with normal aging.
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17.05.2013