Destacats

Cada any, un comitè d'experts s'ha d'enfrontar a la difícil tasca d'escolllir, d'entre totes les publicacions ICREA, unes poques que destaquin sobre la resta. És tot un repte: de vegades els debats s'acaloren, i sempre són difícils, però acaba sortint-ne una llista amb les millors publicacions de l'any. No es concedeix cap premi, i l'únic reconeixement addicional és l'honor d'ésser presentat com a Highlight. Cada publicació té alguna cosa especial, sia una solució especialment elegant a un vell problema, un resó espectacular als mitjans de comunicació o simplement, la fascinació d'una idea revolucionària. Independentment del motiu, es tracta dels millors dels millors i, com a tals, ens plau compartir-los aquí.

LIST OF SCIENTIFIC HIGHLIGHTS

Format: yyyy

  • Higgs Potential Instability Could Have Created Dark Matter (2018)

    Espinosa Sedano, José Ramón (IFAE)

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    Higgs Potential Instability Could Have Created Dark Matter

    Our Universe might be on the edge of destruction, as theory suggests that the Higgs field is in a metastable vacuum. If this field tunneled to its “true” minimum energy state, the release of energy would be cataclysmic. The danger may be over-stated, as other physical mechanisms could have kept the Universe stable throughout its history. Nevertheless, the Higgs instability could have a major cosmological impact as the source of dark matter. According to this new scenario, dark matter consists of a large population of subatomic-size black holes that formed from fluctuations in the Higgs field probing the potential instability at the dawn of the Universe. These so-called primordial black holes have been proposed before, but this is the first hypothesis that doesn’t require physics beyond the standard model (apart from a period of inflation).

    Physicists have long been aware that the Universe might rest in a “false vacuum.” This idea has recently taken on new urgency, as calculations based on the measured top and Higgs masses have shown that a lower energy state may exist for the Higgs field. Analyzing the implications of the Higgs instability, José R. Espinosa (IFAE, Barcelona), Davide Racco and Antonio Riotto (University of Geneva) have found that this menacing mechanism could be instrumental in creating the dark matter that makes galaxies and other life-accommodating structures possible. The team studied fluctuations in the Higgs field during the early inflationary expansion of the Universe. Under certain assumptions, these fluctuations become seeds for microscopic black holes with masses around 1015 kg that could have a density consistent with cosmological predictions of dark matter. If this scenario were correct, the Higgs field would not only be responsible for the masses of elementary particles but also for the dark matter content of our Universe.

    This research was awarded First Prize in the 2018 edition of the Buchalter Cosmology Prize. See http://www.buchaltercosmologyprize.org/

  • An epigenomic profile predicts response to immunotherpay in lung cancer (2018)

    Esteller Badosa, Manel (IDIBELL)

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    An epigenomic profile predicts response to immunotherpay in lung cancer

    A research led by Manel Esteller discovered how an epigenomic profile predicted the clinical response to immunotherapy in lung cancer. The article, published in the journal The Lancet Respiratory Medicine, showed how a particular DNA methylation signature was associated with sensitivity to anti-PD-1 immune checkpoint inhibitors. Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. Although immunotherapies have extended the lives of many patients with advanced disease, a substantial percentage of cancers don’t respond to this treatment strategy. Now, a new study shows that a DNA methylation profile is associated with improved progression-free and overall survival in patients with stage IV NSCLC who received antibodies that block programmed death-1 (PD-1).

    Esteller’s group first established an epigenomic profile based on a microarray DNA methylation signature (EPIMMUNE) in tumor samples from patients treated with different PD-1–targeted antibodies. Next, the EPIMMUNE signature was validated in an independent set of patients. Then, we identified the best single DNA methylation marker that could predict response to PD-1 blockade therapy in patients with NSCLC. The top gene candidate was the T cell-related forkhead box P1 (FOXP1) transcription factor, which the investigators validated by a single-methylation assay in another cohort of patients. It was interesting to see that those EPIMMUNE-positive patients, the responders, presented with a high number of activated T and B lymphocytes, whereas the EPIMMUNE-negative patients, the nonresponders, showed in their tumors more cells of the myeloid lineage, macrophages and neutrophils, more fibrosis and immature blood vessels. The described research also represents a starting point for other studies, such as investigations into whether the DNA methylation markers examined by his team could be new targets for epigenetic drugs, or if the  the identified epigenomic signature can be applied to other tumor types where immunotherapy treatments are starting to be used.

  • New variations uncovered in the silent parts of the genome with a relevance in cancer (2018)

    Eyras Jiménez, Eduardo (UPF)

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    New variations uncovered in the silent parts of the genome with a relevance in cancer

    Cancer genomics has highlighted the prevalence of sequence variants of unknown significance. In our publication we hypothesized that a fraction of these mutations may reflect RNA-related selection processes, thereby impacting RNA metabolism and contributing to oncogenic processes. Analyzing whole genome sequencing data from multiple cancers we uncovered frequent mutations in binding sites for RNA binding proteins and splicing regulators. Furthermore, using RNA sequencing from the same samples validated a change in RNA processing in association to these mutations. We described new alterations in cancer that impact RNA processing and proposed a systematic method for the interpretation of noncoding variants in cancer genomes.

  • Citizens and scientists chart the oral microbiome (2018)

    Gabaldón Estevan, Toni (CRG)

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    Citizens and scientists chart the oral microbiome

    We are not alone. every square inch of our internal and external body surface is populated by a rich and diverse microbial community. Our mouth is not an exception. In fact it is estimated that each milliliter of saliva may contain about 100 million microbial cells, and over 700 bacterial genera have been described in this niche. Identifying the composition of the oral microbiome in adolescents and how it may change with varying dietary and higiene habits was the main research purpose of the “Stick out your tongue” project (http://www.sacalalengua.org).  One particularity of this project is that we took a citizen-science approach, aiming to involve citizens in all steps of the research, from hypothesis generation, through sample collection, to data analysis and interpretation. This approach has enabled us to access a large number of samples and data from a so-far poorly studied population (healthy adolescents) and also to contribute to the empowerment of our citizens in scientific issues. Our results show, for the first time, a relationship of variations in the oral microbiome with the chemical composition of tap water. In addition, many other relationships with dietary and hygiene habits are related. Living in a rural or densely populated environment, in contrast, seemed to have very little effect. Overall, we found that the microbial diversity found in the oral cavity of adolescents belonged to two main "ecotypes" (which we named stomatotypes) that seem to represent two different possible equilibria between microbial communities and our mouths. 

  • Super-resolution microscopy goes multicolour (2018)

    García Parajo, Maria F. (ICFO)

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    Super-resolution microscopy goes multicolour

    Fluorescence microscopy is one of the most powerful tools employed in life sciences as it allows imaging of different molecular components in cells with high specificity and sensitivity. With the advent of super-resolution microscopy, the possibility of visualizing cellular structures at the nanoscale is now within reach. Therefore, the next grand challenge in biology aims at deciphering spatiotemporal molecular interactions within supramolecular complexes and/or sub-cellular organelles. Although molecular interactions play a vital role in diverse cellular functions, so far they have been poorly addressed as fluorescence microscopy is limited in the number of different labels that can be distinguished simultaneously. 

    In 2018 we developed a new approach for simultaneous multicolour confocal or multicolour super-resolution microscopy that overcomes current challenges in fluorescence imaging and dramatically increases image acquisition time. The method relies on the absorption spectra of  fluorescence probes instead of their fluorescence emissions. The method is based on multiplexing optical excitation signals in the frequency domain using single colour-blind detection. Since the spectral information is fully encoded during excitation, the method enables the simultaneous identification of multiple colour channels in a single measurement. We first implemented the method in a confocal configuration and demonstrated simultaneous imaging of six spectrally- and spatially-overlapping fluorophores on fixed cells using four excitation wavelengths. In the case of super-resolution microscopy, we implemented the method in two single molecule localization modalities: DNA-PAINT and STORM. We showed that frequency-multiplexed DNA-PAINT acquires multiple colours at the same time as single-color DNA-PAINT, dramatically improving image acquisition time without compromising the field-of-view or signal throughput. 

    Our new methodology is fully compatible with live cell imaging and as such it will open up wide-ranging opportunities for exploring the molecular mechanisms that underpin supramolecular and/or organelle interactions in living cells with unprecedented levels of detail. 

  • Laser Emission and Amplification of Light in Periodically Ordered Atomic Arrays (2018)

    García de Abajo, Francisco Javier (ICFO)

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    Laser Emission and Amplification of Light in Periodically Ordered Atomic Arrays

    The group lead by García de Abajo have explored the ability of two-dimensional periodic arrays of atoms to produce light amplification and generate laser emission when optical gain is introduced in the system by means of external illumination (i.e., an optical pump). Specifically, they have predicted that light emission of a laser type can take place for arbitrarily weak atomic scatterers (i.e., regardless of how weak is the interaction between light and the atomic transition used for the laser emission), assisted by cooperative interaction among atoms in a 2D periodic lattice. They have based this conclusion on analytical theory for three-level atoms, which additionally revealed a rich interplay between lattice and atomic resonances. Lattice resonances are well known in optics and lie at the heart of widely known phenomena such as the Wood anomalies and extraordinary optical transmission (i.e., funneling of light through arrays of small holes). Their results should provide a general background to understand light amplification and emission of laser light in periodic atomic arrays, with promising applications in the generation, manipulation, and control of coherent photon states at the nanoscale.

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