Highlights

Every year, a committee of experts sits down with a tough job to do: from among all ICREA publications, they must find a handful that stand out from all the others. This is indeed a challenge. The debates are sometimes heated and always difficult but, in the end, a shortlist of  the most outstanding publications of the year is produced. No prize is awarded, and the only additional acknowledge is the honour of being chosen and highlighted by ICREA. Each piece has something unique about it, whether it be a particularly elegant solution, the huge impact it has in the media or the sheer fascination it generates as a truly new idea. For whatever the reason, these are the best of the best and, as such, we are proud to share them here.

LIST OF SCIENTIFIC HIGHLIGHTS

Format: yyyy

  • The cultural diversity of immigrants' social networks predicts their cultural identification(s) and their psychological and behavioral adjustment. (2018)

    Benet-Martínez, Verónica (UPF)

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    The cultural diversity of immigrants' social networks predicts their cultural identification(s) and their psychological and behavioral adjustment.

    Using social-network methodology, we asked Moroccan, Pakistani, Ecuadorian, and Romanian immigrants residing in Barcelona to nominate 25 individuals (i.e., alters) representative of their habitual social networks and to provide demographic (e.g., ethnicity), relationship type (e.g., family, friend, neighbor), and structural (who knew whom) information for each of these alters. Even after controlling for individual-level demographic variables (e.g., time in Spain, income, education), the content and structure of these immigrants’ personal social networks predicted their level of adjustment (both psychological and socio-cultural) and their feelings regarding how compatible their ethnic and Catalan cultures are.

    Specifically, the overall degree of cultural diversity in the network, the amount of Catalan (but not Spanish) “weak” ties (i.e., acquaintances, colleagues, neighbors) in the network, and the amount of interconnectedness between local coethnic and Catalan/Spanish alters positively predicted the above adjustment outcomes. Furthermore, against a “culture and language similarity” hypothesis, Moroccan and Pakistani participants had social networks that were more culturally well-integrated, relative to Ecuadorians and Romanians. Results from this study attest to the importance of examining actual intercultural relations and going beyond individuals’ verbalized acculturation preferences to understand immigrants’ overall adaptation and cultural identity dynamics. Lastly, results highlight the interplay between interculturalism experienced at the meso, interpersonal level (i.e., having culturally diverse networks that also include ties between ethnic and Catalan alters) and intra-personal, subjective level (i.e., feeling that ethnic and Catalan cultures are compatible). 

  • A big machine to look at tiny details: synchrotron-based X-ray imaging of the heart and vessels (2018)

    Bijnens, Bart (UPF)

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    A big machine to look at tiny details: synchrotron-based X-ray imaging of the heart and vessels

    Visualizing and quantifying tissues and organs at a microscopic level of detail has always been an important tool for biomedical research and daily clinical practice. While many microscopic approaches exist nowadays, only recently there are possibilities to study large pieces of tissue or complete organs at high resolution and in 3 dimensions. However, on the one hand, most techniques still require a lot of tissue processing like fixing, staining or optical clearing to use the (mostly optical) imaging approaches. On the other hand, there are the clinical imaging modalities such as X-ray computed tomography, magnetic resonance and ultrasound imaging which provide great information in clinical practice but have limited resolution or contrast, especially for soft tissues.

    Recently, we have shown that using wave-propagation properties of X-rays, rather than only X-ray absorption by tissues, provides a novel way to look at unprocessed tissues and even organs with great contrast and resolution [1,2]. This novel X-ray phase-contrast tomography (X-PCI) requires bright and coherent X-ray beams, which currently can only be produced using synchrotrons, namely large electron accelerators producing bright photon bundles, predominantly for research purposes. 

    The images below show examples of where this approach can shed light and understanding on microscopic tissue remodelling associated with cardiovascular diseases. Fig 1 shows the damage to the elastic laminas of the aorta in (mouse) Marfan syndrome, of which it is known that patients show gradual damage and enlargement of their aortas, often requiring replacement surgery by the age of 40. Fig 2 shows microstructural details of the heart of a normal human fetus as well as a fetus with congenital heart disease, where the homogeneous unique pattern of cardiac muscle cell orientation is importantly distorted, thus leading to an intrinsic inefficient heart muscle and problems to pump blood around.

  • Our bones are flexoelectric – and that’s a good thing (2018)

    Catalán Bernabé, Gustau (ICN2)

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    Our bones are flexoelectric – and that’s a good thing

    Bones have a remarkable ability to fix their own fractures. It has long been known that the repair is carried out by specialized cells. It has also been known for a long time that bones generate electricity in response to mechanical efforts. How, or whether, the self-repair process and the electromechanical properties are related has been less clear until now.

    The ability of bones to generate electricity in response to pressure (known as piezoelectricity) is itself a bit of a mistery, because the mineral component of bones, hydroxyapatite, is not piezoelectric. Scientists have therefore attributed the piezoelectric properties of bone to its main organic component, collagen, which is piezoelectric. However, we have discovered that, even if all the collagen is removed from a bone, it can still generate an electric signal in response to bending. This property is known as “flexoelectricity”, and hydroxyapatite has it. Moreover, when calculating the flexoelectric fields generated around the apex of a bone fracture, we have discovered that they are theoretically large enough to stimulate a strong cellular response from the cells near the fracture.

    The electromechanical link between fractures and repair cells is thus established: when we put pressure on our bones, their fractures will emit an electric signal that acts as a “starting shot” for the initiation of the repair process by the cells. Being very localized around the fracture apex, it also serves as a guiding light to direct the cells to the centre of damage. We hope that this discovery will stimulate the investigation of therapeutic and prosthetic uses of flexoelectricity.

  • A gene visualization tool to see genes in living cells with nanoscopic resolution (2018)

    Cosma, Maria Pia (CRG)

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    A gene visualization tool to see genes in living cells with nanoscopic resolution

    Understanding how our genes are organized in the cell nucleus and how they move in space and time is one of the most exciting and challenging research areas in biology. To unveil the secrets of gene behaviour it is necessary to develop tools to visualize genes in living cells.

    We have recently developed “PoSTAC”, a gene visualization tool to image multiple genes at the same time with high efficiency. Using PoSTAC we could track gene movements with high temporal resolution and visualize them with super-resolution microscopy. We reached ten times greater spatial resolution than with conventional imaging methods. PoSTAC is a flexible tool that can be applied to a wide variety of cell types and genes.

    These technological improvements are key to reveal how genes work in our cells and to dissect at a molecular level how genes get organized during key biological processes and in disease conditions.

  • Advanced computational modelling of the brain explains the effects of LSD (2018)

    Deco, Gustavo (UPF)

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    Advanced computational modelling of the brain explains the effects of LSD

    New work by the research teams led by Gustavo Deco, ICREA research professor and director of the Center for Brain and Cognition, UPF, and  Morten Kringelbach, University of Oxford and Aarhus, published on 27 September 2018 in the journal Current Biology may mean a breakthrough for the treatment of neuropsychiatric diseases.

    A new method to model neuroimaging data could help to predict potential treatment outcomes for patients with mental health disorders. The study by researchers from ICREA/Pompeu Fabra University, and the University of Oxford looked specifically at people with mental disorders attributable to diseases of the nervous system such as depression and addiction. The team used neuroimaging data of healthy participants who had been given LSD (lysergic acid diethylamide) and placebo treatments to prove the concept of the new computer model.

    They used an advanced computer model of human neuroimaging data that precisely modelled whole-brain dynamics using the actual brain connectivity between regions. For the first time, this whole-brain model of neural activity was integrated with the concentrations of the chemical messenger – a serotoninergic neurotransmitter- called 5HT2A, in each brain region. Integrating this information in the model allowed the team to investigate the causal non-linear interactions between neural activity and neurotransmitter concentration. As the concentration of neurotransmitter changes in one or more regions so thus the brain dynamics, but crucially in a non-linear way that requires a model to predict.

  • Researchers discover role of chemical ‘tags’ at two-way gene switches (2018)

    Di Croce, Luciano (CRG)
    Martí-Renom, Marc (CNAG)

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    Researchers discover role of chemical ‘tags’ at two-way gene switches

    ICREA scientists at the Centre for Genomic Regulation in Barcelona, Spain, have uncovered the role of special chemical ‘tags’ in controlling vital genes involved in early mammalian development.

    Led by L Di Croce and MA. Marti-Renom, the study focused on a set of genes with what’s known as bivalent promoters – two-way genetic ‘control switches’ that are poised either to turn on in early development and rapidly drive high levels of gene activity, or to switch off and shut down the gene completely. These genes play essential roles in early development where cells have to make quick decisions about which fate to adopt, so the poised switches allow them to quickly flip into the correct pattern of gene activity.

    Previous work had already shown that there are opposing types of chemical ‘tags’, known as histone modifications, that are present on these two-way switches – one set is associated with gene activation and the other with gene silencing. The active tags are put in place by a molecule called MLL2, while the silencing marks are put on by Polycomb proteins.

    To find out more about the interplay between the two type of histone modifications on the switches, they studied mouse embryonic stem cells growing in the lab. These cells are capable of changing into all the different tissues in the body, and genes with bivalent switches play a key role in setting them off on the right developmental pathway. 

    The researchers used genetic engineering techniques to remove MLL2 from embryonic stem cells, removing all the activating histone modifications from the bivalent gene switches and leaving only the silencing tags and associated Polycomb proteins. They found that these modified cells were no longer able to grow into embryoid bodies, and that many important developmental genes weren’t activated when they should have been. 

    Not only do the team’s findings shed light on the earliest points in development when cells are quickly making decisions about what to do in order to build an embryo, there are also implications for understanding what might have gone wrong when development fails or in diseases involving disrupted gene activity, including cancer. 

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