2020-07-12 17:48:35
The development of the embryo is incredibly complex and marvelous, complex because it must obtain, from a single cell, the trillions of exquisitely differentiated cells to form a living being. It doesn’t take much to realize such wonder, just look in the mirror.
The first cell from which we start, the embryo, contains within it all the information necessary to build the complete being and to achieve this, as it generates daughter cells, it modulates its generation capacity, endowing the daughters with different qualities. according to the role they are going to play in each tissue and in each organ. That specialization comes at a price. The total information is maintained, but it is the way of reading and interpreting that information that varies.
He ADN, the marvelous molecule that contains the genetic code, that is, the complete manufacturing instructions of the living being, resembles a huge library where each step, each instruction, is written in the form of intricate chemical reactions that activate and deactivate genes at each step. exact moment of development. All the cells of our body, with very few exceptions, contain the complete library, however, depending on the tissue to which they belong, they are only capable of reading and executing a part of the information. Thus, a skin cell reads and executes the orders, that is, it activates or deactivates genes, from a section of the library that is different from the section activated by a kidney, heart or liver cell, to give a few examples.
The problem with specialization is that it is not reversible. Once the choice has been made that allows the formation of a particular cell of heart tissue, that specialized cell cannot go back and “reprogram” itself to give daughter cells of another type, at least not naturally. Nature sets a rhythm at which embryonic cells reproduce and change, and there is no turning back from that path. Thus, the embryo is capable of generating all types of daughter cells, regardless of the tissue, and for this reason it is said that it is a “totipotent stem cell”, a capacity that it shares with the cells that form the first stages of development. Later they lose that capacity and in later stages the generated cells continue to be capable of generating different types of cells, but not all of them, they are what are called “pluripotent stem cells” and, thus, burning phases in development they lose that capacity to diversify.
Living beings are not perfect machines, sometimes, due to illness or accidents, their cells suffer damage that needs repair to restore balance. For this reason, in recent years many researchers have placed their hopes in stem cells to treat muscle diseases, nervous system disorders, degenerative processes, etc. This has been called regenerative medicine. The idea is based on obtaining stem cells from a forced “reprogramming”, that is, a reversal in the differentiation process of certain adult and differentiated cells.
Two of the researchers who paved the way for the reprogramming of adult cells to become stem cells were Sir John B. Gurdon and Shinya Yamanaka, for which they received the Nobel Prize in Physiology and Medicine in 2012. Since then, a good number of techniques or protocols that achieve that purpose. However, one of the main limitations in the application of these cell therapies is that, although the return of adult cells to stem cells is achieved, this transformation gives cells that do not have the same quality as the natural ones and that prevents their use. for therapeutic purposes.
Now, a team from the “National Center for Oncological Research (CNIO)”: to which our guest in Talking to Scientists belongs, Maria Salazar Roaa researcher in the Cell Division and Cancer Group, has developed a new, simple and rapid technology that improves the in vitro and in vivo potential of stem cells to differentiate into adult cells.
“In recent years, several protocols have been proposed to obtain reprogrammed stem cells in the laboratory from adult cells, but very few to improve the cells we already have. The method we developed can significantly increase the quality of stem cells obtained by any other protocol, thus favoring the efficiency of the production of specialized cell types”, says María Salazar-Roa.
The improvement is due to the use of a sequence of ARN, called microRNA 203, which is present in the early stages of embryo development, when it is formed by totipotent stem cells. By adding this 203 microRNA to stem cells obtained by different protocols in the laboratory, the researchers discovered that there was a marked improvement in the cells’ ability to convert to other cell types.
The study, which has been published in the journal EMBO J, indicates that the cells modified by this new protocol are more efficient in the generation of functional cardiac cells, opening the door to an improved generation of different types of cells necessary for the treatment of degenerative diseases.
I invite you to listen to Maria Salazar Roaresearcher of the Cell Division and Cancer Group of the “National Center for Oncological Research (CNIO)”:
References:
Transient exposure to miR-203 enhances the differentiation capacity of established pluripotent stem cells. María Salazar-Roa, Marianna Trakala, Mónica Álvarez-Fernández, Fátima Valdés-Mora, Cuiqing Zhong, Jaime Muñoz, Yang Yu, Timothy Peters, Osvaldo Graña-Castro, Rosa Serrano, Elisabet Zapatero-Solana, María Abad, María J. Bueno , Marta Gómez de Cedrón, José Fernández-Piqueras, Manuel Serrano, María Blasco, Da-Zhi Wang, Susan Clark, Juan Carlos Izpisúa-Belmonte, Sagrario Ortega and Marcos Malumbres (EMBO J, 2020). DOI: 10.15252/embj.2019104324
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