Why is the heart not being renewed
A mechanism has been discovered that prevents the heart tissue from self-healing
Anna Stavina, XX2 century
The tissue of the heart muscle is actually not capable of recovery. That is why cardiovascular diseases are so dangerous - in many countries (including the USA and They are the most common cause of death for both men and women. Scientists from the Baylor College of Medicine and the Texas Heart Institute, inspired by the idea of self-healing of the heart, decided to study the signaling pathways used by heart tissue cells. Researchers were able to discover a previously unknown connection between the processes that prevents the heart from recovering. The results of the work of Dystrophin glycoprotein complex sequesters Yap to inhibit cardiomyocyte proliferation, published in the journal Nature, in the future may lead to the emergence of strategies that will make the renewal of cardiac tissue possible.
"We are finding out why the heart muscles are not being renewed," says lead author of the study, Dr. James Martin, professor of regenerative medicine at Baylor College of Medicine. – In the course of the new study, we focused on two signaling pathways used by cardiomyocytes, muscle cells of the heart. We studied the Hippo signaling pathway, which stops the renewal of mature cardiomyocytes, and the signaling pathway of the dystrophin-associated glycoprotein complex (DAG complex), which is necessary for the normal functioning of these cells."
A signaling pathway is a sequence of molecules by which information from a cellular receptor is transmitted inside a cell. The signal is transmitted from molecule to molecule in a strictly defined order, which allows us to talk about the signaling pathway. Most signaling pathways are activated in response to signals external to the cell, such as neurotransmitters, hormones, and growth factors. The minority begins with signals generated inside the cell.
Scientists have also studied mutations of genes associated with the synthesis of the DAG complex, since people with such mutations develop dangerous genetic diseases, myodystrophy or, as they are also called, muscular dystrophy.
In previous studies, it was shown that the components of the signaling pathway of the DAG complex can somehow interact with the components of the Hippo signaling complex. In the new study, Dr. Martin and his colleagues studied the effects of these interactions in animal models. Using genetic engineering, the researchers derived lines of mice that lacked genes associated with the first, second, or both signaling pathways. Then the scientists observed the condition of the animals' heart tissue and its ability to renew. During the study, it was shown for the first time that dystroglycan-1, a component of the signaling pathway of the DAG complex, is directly attached to the Yap protein, a component of the Hippo signaling pathway. It is this attachment that blocks the process of division of cardiomyocytes.
"The discovery of the fact that Hippo and DAG signaling pathways intersect in heart cells and act as a "brake" on cell division opens up new prospects. Perhaps someday the destruction of this interaction of signaling pathways will lead to the fact that we will "teach" mature cardiomyocytes to multiply, for example, to heal the damage caused by myocardial infarction," says Dr. Martin (in a press release Baylor College of Medicine New insight into why the heart does not repair itself - VM).
Also, the results of the new study can be used to improve the functioning of the heart in children suffering from myodystrophy.
"Patients with muscular dystrophy often also suffer from serious cardiac disorders," explains Dr. Martin. – Our findings may help in the development of medications that slow the progression of these disorders by stimulating the reproduction of cardiomyocytes. But to achieve this, we need to conduct additional research on the signaling pathways that control the growth of heart cells."
Portal "Eternal youth" http://vechnayamolodost.ru
07.06.2017