Binucleated cells could be the key in heart regeneration

A research team led by the IBEC, in collaboration with the CMR [B], discovers a mechanism that generates binucleated cells.This mechanism has been identified during the regeneration of the heart of the zebrafish, and could be associated with the extraordinary regenerative power of this animal.

Cells of the epicardium of the zebrafish with two nuclei (in blue)

After an acute heart lesion, such as a myocardial infarction, the human heart is unable to regenerate. The adult cardiac cells cannot grow and divide to replace the damaged ones, and the lesion becomes irreversible. But this does not happen in all animals. A freshwater fish native to Southeast Asia, known as a zebrafish, can completely regenerate its heart even after 20% ventricular amputation.

This extraordinary regenerative capacity has attracted the attention of researchers from all over the world, who see the range of possibilities that would be opened up if this mechanism of cell regeneration could be applied in human therapies.

In an article published today in the Nature Materials journal, a team of researchers from the Institute of Bioengineering of Catalonia (IBEC) led by Xavier Trepat, in collaboration with the Centre for Regenerative Medicine in Barcelona (CMR [B]), have discovered a surprising mechanism by which zebrafish heart cells move and divide during regeneration.

Researchers have focused on the epicardium, which is the layer of cells on the outer surface of the heart. Although the epicardium cells represent only a small fraction of the heart’s mass, they play a fundamental role in its regeneration. “The epicardium is the origin of several of the heart’s cell types, and secretes biochemical signals that tell the cells what they have to do at all times. It’s a kind of regeneration ‘hub’”, states Angel Raya, ICREA Researcher and director of CMRB.

After a heart lesion, the epicardium cells begin to divide and move en masse to cover the wound. Researchers have observed that, during this process, the cells become binucleated: they duplicate the genetic material and separate it into two nuclei, but they are not divided into two independent cells. “We were very surprised to discover cells that, instead of having one nucleus, as is the case in most tissues, they have two nuclei, and each of them contains a copy of the cell’s DNA” says Trepat, ICREA researcher at IBEC and associate professor of the University of Barcelona.

Researchers have discovered that the mechanism by which cells become binucleated has a biomechanical origin. Once DNA has already separated into two nuclei, most animal cells form a contractile ring at its centre. As it contracts, this ring divides the mother cell into two daughter cells. In the case of the heart cells of the zebrafish, the study shows that the ring adheres to the fibres of its environment so that it cannot tighten. The result is that the two daughter cells cannot separate despite having correctly duplicated their DNA.

“Multinucleation is a well-known phenomenon in cancer, because it is a cause of genetic instability. In other words, cancer cells lose control of the proteins they synthesise and behave pathologically. In the case of the heart of zebrafish, the multinucleation is physiological and does not seem to cause any problem”, states Marina Uroz, the article’s main author. The next step will be to study the role of multinucleated cells during the regeneration of the heart and other organs.

Dr. Trepat and Dr. Raya are part of CIBER-BBN (Biomedical Research Networking Centre in Bioengineering, Biomaterials and Nanomedicine)

Pere Roca-Cusachs and Antoine Khalil participate at the 2019 Gordon Research Conference

Pere Roca-Cusachs and Antoina Khalil in Lucca during the GRC

Last 5th-10th May was held the 2019 Gordon Research Conference on “Fibronectin, Integrins and Related Molecules” where Pere Roca-Cusachs from IBEC and Antoine Khalil from UMCU presented talks discussing Mechanocontrol results on how mechanical signals and the extracellular matrix regulate cell responses and tumour invasion. During the keynote session titled “Mechanisms and Mechanics of Integrin ECM Connections” Pere Roca-Cusachs gave a talk on “Exploring the Substrate Dependence of Integrin-Mediated Mechanotransduction”. Antoine gave an oral presentation where he described how cell-ECM adhesion regulates the positioning of basal cells and their specification into invasive leader cells during collective invasion of breast cancer organoids.

The Gordon Research Conference was held in Lucca, Italy and is the premier international conference for academic, government and industry scientists interested in understanding how integrins and the extracellular matrix regulate virtually every aspect of cell and tissue function. The program of the conference reflected the interdisciplinary nature of the integrin and extracellular matrix field, spanning different areas of biology from inflammation to mechanobiology, cell migration, stem cells, development, and cancer. During the meeting unpublished data was highlighted and stimulated active discussion among all participants.

Registration for Mechanobiology of Cancer Summer School 2019 is now opened

The MECHANO·CONTROL consortuium is launching the website for the “Mechanobiology of Cancer Summer School 2019” for the application process and registration.

The application period opens today until the 8th May 2019, where you can submint an abstract if you are interested in giving a short talk during the summer school.

The application does not guarantee acceptance to the Summer School due to the limited number of participants, an email with the resolution of the applicaton process will be sent on June 15th 2019.

The summer school will be held in La Cerdanya at the Eco-Resort located in Prullans in the Catalan Pyrenees.

The participation fee is 300€ (taxes not included) and includes accomodation in shared double room (from 17th-20th September 2019), full-board, workshops and conferences, leisure activities and shuttle bus from Barcelona to the venue.

Two more exchanges within the Mechano·Control consortium

IBEC is hosting two members from the Mechano·Control network. On the one hand, Dimitri Kaurin, PhD student from Marino Arroyo group at Universitat Politècnica de Catalunya (UPC) that will be staying at IBEC for at least one year and on the other hand, Amy Beedle, postdoc from Sergi Garcia-Manyes at Kings College London (KCL).

Dimitri Kaurin started his stay at Pere Roca-Cusachs’ laboratory in December 2018 and it is planned to be for at least a year. One of the objectives of Dimitri’s stay is to work on a protocol to study cell-cell adhesion using a controlled system based on lipid bilayers of controlled viscosity. “Using AFM technique, we expect to access some information about cell-cell adhesion under force” says Dimitri. In the context of this research he will also visit Manuel Salmeron laboratory in Glasgow University this march to learn some techniques about functionalizing lipid bilayers with cadherins.


Dimitri Kaurin working in the laboratory at IBEC

On the other hand, Amy Beedle arrived this past January to Pere Roca-Cusachs’ laboratory. In the Garcia-Manyes lab Amy was looking at how mechanical forces can trigger conformational changes in individual proteins. Here at IBEC, she wants to incorporate the results at the single molecule level with the cellular level, to try to understand how individual bonds and proteins can contribute to cellular mechanosensing. “My aim is to expand my expertise in single molecule force spectroscopy to a larger cellular context” adds Amy.

Amy Beedle working in the laboratory at IBEC

This is the first time that both UPC and KCL teams meet with IBEC to share skills and ideas within the project’s framework.