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Cells use a great variety of mechanisms in order to reach their purpose.

During the last few years, it has been acknowledged the existence of a type of nanoparticles called exosomes as one of the many signalling tools employed by the cells.

Exosomes are part of an even greater family, known as extracellular vesicles. These vesicles are secreted by the cells and allow them to communicate with their environment.

Their ways of communication include the use of proteins or nucleic acids such as RNA. Besides, because of their particular characteristics, for instance their biological composition or size, exosomes have become particles of utmost importance when talking about therapeutics.

Their potential to overcome obstacles that more traditional therapies such as cells or drugs must face puts them in the spotlight.

What does the project consist of?

The main area of expertise in the Laboratory of Immune Regulation is the study of thymic-derived regulatory T cells (thyTregs) in order to reach their highest therapeutic effect.

One of the lines of research pursuing this goal is the identification and understanding of thyTregs signalling mechanisms and particularly exosomes so that they can be used as therapy.

Moreover, since many studies have reported the relevance of plasma exosomes as biomarkers to predict disease development, plasma exosomes in paediatric heart-transplanted patients are also being investigated in the laboratory.

Defining a plasma exosome profile that could predict the probability of rejection in these patients may allow taking action as soon as possible, reducing the damage caused or even preventing it from happening.

Currently, cardiac biopsy is a widely used tool to evaluate the chances of rejection.

By developing a plasma exosome profile that can reach the same conclusion as the traditional ways may be life-changing, especially for patients, since plasma can be easily obtained from a blood sample and therefore represents a much less invasive approach.

Exosomes are identified as the white dots moving from left to right. The measurement was performed using a nanoparticle analysis device.

EXOSOMES are represented by each of the points that are observed on the screen and move from right to left in a fluid.


So far, thyTregs-derived exosomes have been obtained. Their characterization is now in a very advanced state, which may allow concluding that, yes, thyTregs do secrete these vesicles.

ThyTregs exosomes have been defined based on their size, concentration of particles, and their biological morphology or phenotype by a variety of techniques performed in the laboratory.

An exosome isolation protocol from plasma has also been developed, allowing as well the characterization of these particles by their size and phenotype.


  • Ectopic FOXP3 Expression in Combination with TGF-β1 and IL-2 Stimulation Generates Limited Suppressive Function in Human Primary Activated Thymocytes Ex Vivo.Jorge Gallego-Valle, Sergio Gil-Manso, Ana Pita, Esther Bernaldo-de-Quirós, Rocío López-Esteban, Marta Martínez-Bonet, Verónica Astrid Pérez-Fernández, Ramón Pérez-Caballero, Carlos Pardo, Juan-Miguel Gil-Jaurena, Rafael Correa-Rocha and Marjorie Pion. Biomedicines 2021, 9(5), 461


  • Marta Fernández, Laboratorio de Inmuno-Regulación. Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM).
  • Rocío López, Laboratorio de Inmuno-Regulación. Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM).
  • Marjorie Pion, Laboratorio de Inmuno-Regulación. Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM).
  • Rafael Correa, Laboratorio de Inmuno-Regulación. Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM).