Interactions between BRD4S, LOXL2, and MED1 drive cell cycle transcription in triple‐negative breast cancer

Cell cycle; Gene expression; Triple-negative breast cancerCiclo celular; Expresión génica; Cáncer de mama triple negativoCicle cel·lular; Expressió gènica; Càncer de mama triple negatiuTriple‐negative breast cancer (TNBC) often develops resistance to single‐agent treatment, which can be circumvented using targeted combinatorial approaches. Here, we demonstrate that the simultaneous inhibition of LOXL2 and BRD4 synergistically limits TNBC proliferation in vitro and in vivo. Mechanistically, LOXL2 interacts in the nucleus with the short isoform of BRD4 (BRD4S), MED1, and the cell cycle transcriptional regulator B‐MyB. These interactions sustain the formation of BRD4 and MED1 nuclear transcriptional foci and control cell cycle progression at the gene expression level. The pharmacological co‐inhibition of LOXL2 and BRD4 reduces BRD4 nuclear foci, BRD4‐MED1 colocalization, and the transcription of cell cycle genes, thus suppressing TNBC cell proliferation. Targeting the interaction between BRD4S and LOXL2 could be a starting point for the development of new anticancer strategies for the treatment of TNBC.We thank the CRG genomics unit, the CRG‐UPF flow cytometry unit, and the VHIO mouse facility for their contribution. We thank Pharmaxis for the supply of PXS LOXL2 inhibitors. SS is supported by the Plan Estatal de I + D + I (COMBAT PID2019‐110598GA‐I00), and the ERC Starting Grant (ERC‐StG‐852343‐EPICAMENTE). LP‐R is supported by the Juan de la Cierva‐Formación fellowship (FJC2019‐040598‐I) and Fundación Franscico Cobos fellowship. TVT is supported by Plan Estatal de I + D + I (PID2019‐108008RJ‐I00), AECC (INVES20036TIAN), and a Ramón y Cajal investigator contract (RYC2020‐029098‐I). DC is supported by the la Caixa Foundation PhD fellowship (ID 100010434; fellowship code LCF/BQ/DI19/11730061)

Histone H1 depletion triggers an interferon response in cancer cells via activation of heterochromatic repeats

Histone H1 has seven variants in human somatic cells and contributes to chromatin compaction and transcriptional regulation. Knock-down (KD) of each H1 variant in breast cancer cells results in altered gene expression and proliferation differently in a variant specific manner with H1.2 and H1.4 KDs being most deleterious. Here we show combined depletion of H1.2 and H1.4 has a strong deleterious effect resulting in a strong interferon (IFN) response, as evidenced by an up-regulation of many IFN-stimulated genes (ISGs) not seen in individual nor in other combinations of H1 variant KDs. Although H1 participates to repress ISG promoters, IFN activation upon H1.2 and H1.4 KD is mainly generated through the activation of the IFN response by cytosolic nucleic acid receptors and IFN synthesis, and without changes in histone modifications at induced ISG promoters. H1.2 and H1.4 co-KD also promotes the appearance of accessibility sites genome wide and, particularly, at satellites and other repeats. The IFN response may be triggered by the expression of noncoding RNA generated from heterochromatic repeats or endogenous retroviruses upon H1 KD. In conclusion, redundant H1-mediated silencing of heterochromatin is important to maintain cell homeostasis and to avoid an unspecific IFN response

Distinct tissue niches direct lung immunopathology via CCL18 and CCL21 in severe COVID-19

Prolonged lung pathology has been associated with COVID-19, yet the cellular and molecular mechanisms behind this chronic inflammatory disease are poorly understood. In this study, we combine advanced imaging and spatial transcriptomics to shed light on the local immune response in severe COVID-19. We show that activated adventitial niches are crucial microenvironments contributing to the orchestration of prolonged lung immunopathology. Up-regulation of the chemokines CCL21 and CCL18 associates to endothelial-to-mesenchymal transition and tissue fibrosis within these niches. CCL21 over-expression additionally links to the local accumulation of T cells expressing the cognate receptor CCR7. These T cells are imprinted with an exhausted phenotype and form lymphoid aggregates that can organize in ectopic lymphoid structures. Our work proposes immune-stromal interaction mechanisms promoting a self-sustained and non-resolving local immune response that extends beyond active viral infection and perpetuates tissue remodeling

Chromatin reorganization during epithelial-to-mesenchymal transition : a role for euchromatin lamin B1 domains

Les làmines nuclears (A/C i B) són els majors constituents de la làmina nuclear (NL). Els estructuralment conservats dominis associats a les làmines (LADs) estan formats per regions genòmiques que contacten amb la NL. Tot i així, les làmines també s’han trobat dins del nucleoplasma però el paper de les làmines nuceloplasmàtiques encara està per definir. En aquesta tesis, hem mapat la localització de la Lamina B1 en tot el genoma de ratolí en una fracció enriquida en eucromatina i hem seguit el seu dinamisme durant la transició epiteli-mesènquima (EMT). La lamina B1 s’associa amb eucromatina activament expressada i oberta, formant dominis d’eucromatina associats a la lamina B1 (eLADs) dinàmics amb una mida mitjana de 0.3Mb. Les dades del Hi-C relacionen els eLADs amb la organització tri-dimensional del genoma de ratolí durant el procés de transició epiteli-mesènquima i correlaciona l’enriquiment de la lamina B1 a les fronteres de dominis d’associació topològics (TADs) amb un increment de la força de les fronteres. Nivells reduïts de lamina B1 alteren el la EMT i comprometen l’adquisició de característiques mesenquimals. Per tant, el genoma de ratolí necessita de dominis plàstics i dinàmics (eLADs) que continguin nivells predeterminats de lamina B1 per tal que es completi la EMT.The nuclear lamins A/C and B are major constituents of the nuclear lamina (NL). Structurally conserved lamina-associated domains (LADs) are formed by genomic regions that contact the NL. However, lamins are also found in the nucleoplasm, where their role is still unknown. In this thesis, we map the genome-wide localization of lamin B1 into an euchromatin-enriched fraction of the mouse genome and follow its dynamics during the epithelial-to-mesenchymal transition (EMT). Lamin B1 associates with actively expressed and open euchromatin, forming dynamic euchromatin laminB1-associated domains (eLADs) with an average size of 0.3 Mb. Hi-C data link eLADs to the three-dimensional (3D) organization of the mouse genome during EMT process and correlate lamin B1 enrichment at topologically associating domain (TAD) borders with increased border strength. Importantly, reduced levels of lamin B1 alter the EMT signature and compromise acquisition of mesenchymal traits. Therefore, the mouse genome requires dynamic and plastic domains (eLADs) that contain predetermined lamin B1 levels in order to undergo EMT

Multiplexed histology of COVID-19 post-mortem lung samples - CONTROL CASE 1 FOV3

Image-based data set of a post-mortem lung sample from a non-COVID-related pneumonia donor (CONTROL CASE 1 FOV3) Each image shows the same field of view (FOV), sequentially stained with the depicted fluorescence-labelled antibodies, including surface proteins, intracellular proteins and transcription factors. Images contain 2024 x 2024 pixels and are generated using an inverted wide-field fluorescence microscope with a 20x objective, a lateral resolution of 325 nm and an axial resolution above 5 µm. Images have been normalized and intensities adjusted.Funding: Deutsche Forschungsgemeinschaft HA5354/10-1, SPP1937 (HA5354/8-2) and TRR130 P17 and C01 (to Anja Hauser

Entschlüsselung von gewebsspezifischen Signalen und molekularen Mechanismen unter der Kontrolle von TH17 Zellen

TH17 cells are major drivers of inflammation and are involved in several autoimmune diseases. Tissue inflammation is a beneficial host response to infection but, when deregulated, can also contribute to autoimmunity. The crosstalk between the inflamed tissue and the immune system during an inflammatory response is the key for preserving tissue integrity and to maintain physiological processes. However, how the inflamed tissue is able to regulate the magnitude of an immune response by controlling pro-inflammatory T cells is not well characterized. In addition, during the resolution of tissue inflammation several antigen presenting cells (APCs) with tolerogenic properties are known to further push the system back to homeostasis through the expression of anti-inflammatory mediators that ultimately influence T cell fate. Here, we show that intestinal epithelial cells (IEC) are the main source of the alarmin interleukin-33 (IL-33) upon T cell dependent intestinal inflammation and that TH17 cells express the IL-33 receptor (ST2) in vivo. Also, we show that monocytes repopulating the lamina propria (LP) during the resolution of inflammation are the main source of Oncostatin (OSM) and that TH17 cells express the OSM receptor (OSMRβ). Both IL-33 and OSM promote a reduced expression of pro-inflammatory genes (Tbx21, Ifng and Csf2) and induce the expression of the anti-inflammatory gene Il10 in mouse and human TH17 cells. In vivo experiments performed with St2-/- mice demonstrate that IL-33 signaling limits the pro-inflammatory capacity of TH17 cells in the small intestine (SI) upon acute inflammation, thereby ameliorating the clinical course. Similarly, in vivo experiments performed with Experimental Autoimmune Encephalomyelitis (EAE)-induced mice demonstrate that OSM also restrains TH17 pathogenicity, thereby attenuating disease severity. Finally, we show that pro-inflammatory TH17 cells acquire a regulatory phenotype with immune- suppressive properties in response to both IL-33 and OSM. Our results provide new insights into the mechanisms by which IEC, via IL-33/ST2 axis, and monocytes, via OSM/OSMRβ axis, may control pro-inflammatory TH17 cells in the small intestine in order to sustain homeostasis.TH17-Zellen spielen eine große Rolle bei Entzündungen und sind in einigen Autoimmunerkrankungen involviert. Die Entzündungsreaktion im Gewebe ist eine protektive Antwort des Organismus auf Infektionen, kann allerdings, wenn sie fehlreguliert ist, auch zur Autoimmunität führen. Während einer Immunantwort ist der Austausch zwischen dem entzündlichen Gewebe und dem Immunsystem der Schlüssel, um die Gewebeintegrität zu erhalten und physiologische Prozesse aufrechtzuerhalten. Wie das inflammatorische Gewebe das Ausmaß der Immunreaktion durch die Kontrolle von proinflammatorischen T-Zellen reguliert, ist nicht genau charakterisiert. Zusätzlich sind einige Antigen-präsentierende Zellen (APCs) bekannt, die zum Rückgang einer Gewebeentzündung und zur Wiederherstellung der Homöostase durch deren Expression von antiinflammatorischen Mediatoren führen, und schließlich das Schicksal der T-Zellen beeinflussen. Hier konnten wir zeigen, dass intestinale Epithelzellen (IEC) die größte Quelle für das Alarmin Interleukin-33 (IL-33) nach einer T -Zell-abhängigen Inflammation ist und dass TH17-Zellen den IL-33-Rezeptor (ST2) in vivo exprimieren. Daneben konnten wir zeigen, dass Monozyten, die die Lamina propria (LP) während des Rückgangs der Entzündung neu besiedeln, die Hauptquelle für Oncostatin (OSM) sind und dass TH17-Zellen den OSM-Rezeptor (OSMRβ) exprimieren. IL-33 und OSM reduzieren beide die Expression von proinflammatorischen Genen (Tbx21, Ifng und Csf2) und induzieren die Expression des antiinflammatorischen Gens Il10 in der Maus und in humanen TH17-Zellen. In vivo-Experimente, die in St2-/--Mäusen durchgeführt wurden, zeigten, dass IL-33-Signale die proinflammatorischen Kapazitäten von TH17-Zellen im Dünndarm nach akuter Entzündung limitieren, und somit den klinischen Verlauf positiv beeinflussen. Passend dazu zeigten in vivo- Experimente in Mäusen, in denen experimentelle autoimmune Enzephalomyelitis (EAE) induziert wurde, dass OSM auch die TH17-Pathogenität eindämmt, und folglich die Schwere der Erkrankung reduziert. Schließlich zeigen wir, dass sich während der Antwort auf IL-33 und OSM proinflammatorische TH17-Zellen entwickeln, die einen regulatorischen Phänotyp mit immunsuppressiven Eigenschaften aufweisen. Unsere Ergebnisse liefern neue Einblicke in den Mechanismus, wie IEC über die IL-33/ST-Achse und wie Monozyten über die OSM /OSMRβ-Achse proinflammatorische TH17-Zellen im Dünndarm kontrollieren könnten, um die Homöostase aufrechtzuerhalten

Chromatin reorganization during epithelial-to-mesenchymal transition : a role for euchromatin lamin B1 domains

Les làmines nuclears (A/C i B) són els majors constituents de la làmina nuclear (NL). Els estructuralment conservats dominis associats a les làmines (LADs) estan formats per regions genòmiques que contacten amb la NL. Tot i així, les làmines també s’han trobat dins del nucleoplasma però el paper de les làmines nuceloplasmàtiques encara està per definir. En aquesta tesis, hem mapat la localització de la Lamina B1 en tot el genoma de ratolí en una fracció enriquida en eucromatina i hem seguit el seu dinamisme durant la transició epiteli-mesènquima (EMT). La lamina B1 s’associa amb eucromatina activament expressada i oberta, formant dominis d’eucromatina associats a la lamina B1 (eLADs) dinàmics amb una mida mitjana de 0.3Mb. Les dades del Hi-C relacionen els eLADs amb la organització tri-dimensional del genoma de ratolí durant el procés de transició epiteli-mesènquima i correlaciona l’enriquiment de la lamina B1 a les fronteres de dominis d’associació topològics (TADs) amb un increment de la força de les fronteres. Nivells reduïts de lamina B1 alteren el la EMT i comprometen l’adquisició de característiques mesenquimals. Per tant, el genoma de ratolí necessita de dominis plàstics i dinàmics (eLADs) que continguin nivells predeterminats de lamina B1 per tal que es completi la EMT.The nuclear lamins A/C and B are major constituents of the nuclear lamina (NL). Structurally conserved lamina-associated domains (LADs) are formed by genomic regions that contact the NL. However, lamins are also found in the nucleoplasm, where their role is still unknown. In this thesis, we map the genome-wide localization of lamin B1 into an euchromatin-enriched fraction of the mouse genome and follow its dynamics during the epithelial-to-mesenchymal transition (EMT). Lamin B1 associates with actively expressed and open euchromatin, forming dynamic euchromatin laminB1-associated domains (eLADs) with an average size of 0.3 Mb. Hi-C data link eLADs to the three-dimensional (3D) organization of the mouse genome during EMT process and correlate lamin B1 enrichment at topologically associating domain (TAD) borders with increased border strength. Importantly, reduced levels of lamin B1 alter the EMT signature and compromise acquisition of mesenchymal traits. Therefore, the mouse genome requires dynamic and plastic domains (eLADs) that contain predetermined lamin B1 levels in order to undergo EMT

Els teus ulls t'enganyen?

Treball de recerca realitzat per alumnes d’ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l’any 2008. Per què cada persona interpreta d’una manera diferent una il•lusió òptica? Quins són els factors que afecten a aquesta interpretació diferent de la realitat? S’analitzen els conceptes de percepció i il•lusió òptica mitjançant una recerca bibliogràfica. Posteriorment s’ha investigat per esbrinar els possibles factors que distorsionen la percepció. Algunes limitacions, com ara el temps i els recursos necessaris només han permés centrar-se en quatre factors: la miopia, l’astigmatisme, l’edat i el sexe. La recerca que s’ha dut a terme consisteix en la realització d’unes enquestes i la posterior extracció de les conclusions a partir d’aquestes mitjançant un programa estadístic. Es conclou que els defectes visuals i l’edat són factors importants que alteren la percepció visual; els factors socioculturals afecten en part la mateixa percepció, i el sexe no afecta la percepció visual

Multiplexed histology of COVID-19 post-mortem lung samples - CONTROL CASE 2 FOV1

Image-based data set of a post-mortem lung sample from a non-COVID-19-related pneumonia donor (CONTROL CASE 2 FOV1) Each image shows the same field of view (FOV), sequentially stained with the depicted fluorescence-labelled antibodies, including surface proteins, intracellular proteins and transcription factors. Images contain 2024 x 2024 pixels and are generated using an inverted wide-field fluorescence microscope with a 20x objective, a lateral resolution of 325 nm and an axial resolution above 5 µm. Images have been normalized and intensities adjusted.Funding: Deutsche Forschungsgemeinschaft HA5354/10-1, SPP1937 (HA5354/8-2) and TRR130 P17 and C01 (to Anja Hauser

Multiplexed histology of COVID-19 post-mortem lung samples - ACUTE CASE 3 FOV2

Image-based data set of a post-mortem lung sample from a COVID-19 donor (ACUTE CASE 3 FOV2) Each image shows the same field of view (FOV), sequentially stained with the depicted fluorescence-labelled antibodies, including surface proteins, intracellular proteins and transcription factors. Images contain 2024 x 2024 pixels and are generated using an inverted wide-field fluorescence microscope with a 20x objective, a lateral resolution of 325 nm and an axial resolution above 5 µm. Images have been normalized and intensities adjusted.Funding: Deutsche Forschungsgemeinschaft HA5354/10-1, SPP1937 (HA5354/8-2) and TRR130 P17 and C01 (to Anja Hauser