A set of new technologies allows you to immerse yourself in the body of living beings and explore all your organs, cell by cell. It is a vision of life that until a few years ago was impossible. This set of techniques, known as individual cell RNA sequencing, is the discovery of the year, according to the prestigious journal Science.
These techniques, whose use has been universalized since 2013, allow us to know which genes are active in a cell, to know its function, to mark it to follow it throughout its life and to see how it interacts with other cells in a three-dimensional plane. So you can see how an embryo of some cells gives rise to different organs to generate a healthy individual or unravel the molecular processes that cause cancer and other diseases.
About five years ago, these techniques allowed for sequencing as many hundreds of cells at a time; now several hundred thousand can be analyzed. This allows to characterize entire organs and even whole organisms. One of the applications of this technology is to find new types of cells in the human body. This year, a new class of cells present in the area of contact between the uterus and the placenta, which perform a task of mediation with the mother's immune system, was discovered so that the mother recognizes the fetus and does not attack during the first months gestation. The same thing happened in the brain or in the respiratory system.
"If we used to think there were about 3,000 different types of cells in the human body, we now believe that they are 10 times more," explains Holger Heyn, a researcher at the National Center for Genomic Analysis in Barcelona and one of the coordinators of Atlas Cell phone. Human
This initiative, which emerged in 2016 and involves more than 1,000 scientific teams from 58 countries, will provide the first cellular map of 10 human organs in 2022. "These techniques will provide us with a full human body Google Maps in which we can zoom into each organ and we will first have a reference to a healthy body and then they will be aggregating specific disease profiles, "he explains.
The Heyn team focuses on the atlas of the B cells of the immune system. "These cells play a key role in chronic lymphocytic leukemia and, thanks to this technique, we can know what's wrong with these cells. For example, we'll look at the blood of non-responders and others who do not relapse after receiving the drugs, so we can predict the prognosis of a particular patient and adapt the treatments, for example, to give a very aggressive treatment or not, "he explains.
From the development of the first atlas of human cells, the European project LifeTime aims to analyze the origin and progression of cancer and other diseases at the cellular level. This initiative also contributes to obtain funding of 1 billion euros from the European Commission. These types of techniques are used in animal models and human tissues, but can not be applied for the time being in living people. In any case, experts emphasize that this need not be a limitation for possible medical uses.
The Nikolaus Rajewsky team, one of the coordinators of the European project, develops human mini-organs created from reprogrammed patient cells for which individual cell sequencing can be applied and see how they change with different drugs.