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SummaryHematopoietic stem cells (HSCs) develop within a short time window from the hemogenic endothelium in the aorta- gonads-and mesonephros (AGM) region during embryonic development. The first HSCs reside within Intra-aortic hematopoietic clusters (IAHC) along with hematopoietic progenitors (HPC). The signalling mechanisms that divert HSCs from HPCs are unknown. Notch signaling is essential for arterial specification, IAHC formation and HSC activity, but current studies on how Notch drives these different fates are inconsistent. To determine the role of Notch in the specification of hemogenic endothelium, HSC and/or HPCs, we extensively analyzed Notch dynamics in the period of HSC generation. We defined the expression pattern of Notch signalling molecules at the gene and protein level and established a molecular mechanism that reconcile previous studies demonstrating the loss of HSC activity in NOTCH1, JAG1 and RBPJ null mutants, the enhanced HSC generation by blocking specific Notch activities or the abrogation of emerging HSCs by high Notch activation. We now demonstrate that Notch activity is highest in a subset of Gfi1+ hemogenic endothelial cells and is gradually lost with HSC maturation. We uncover that the HSC phenotype is maintained through loss of Notch activity due to increasing levels of NOTCH1 and JAG1 interactions on the surface of the same cell (cis) that renders the NOTCH1 receptor from being activated. Forcing activation of the NOTCH1 receptor in IAHC cells activates a hematopoietic differentiation program and supports acis-inhibitory function for JAG1 and NOTCH1. Furthermore, we demonstrate that thiscis-inhibitory interaction is enabled by RADICAL FRINGE (RFNG), a glycosyltransferase that enhances the affinity of NOTCH1 to JAG1 incis. Finally, our results indicate that NOTCH1-JAG1cis-inhibition is necessary for preserving the HSC phenotype in the hematopoietic clusters of the aorta.

Multiple transcription factors have been shown to promote pancreatic β-cell differentiation, yet much less is known about negative regulators. Earlier epigenomic studies suggested that the transcriptional repressor REST could be a suppressor of endocrinogenesis in the embryonic pancreas. However, pancreatic Rest knockout mice failed to show abnormal numbers of endocrine cells, suggesting that REST is not a major regulator of endocrine differentiation. Using a different conditional allele that enables profound REST inactivation, we observed a marked increase in pancreatic endocrine cell formation. REST inhibition also promoted endocrinogenesis in zebrafish and mouse early postnatal ducts and induced β-cell-specific genes in human adult duct-derived organoids. We also defined genomic sites that are bound and repressed by REST in the embryonic pancreas. Our findings show that REST-dependent inhibition ensures a balanced production of endocrine cells from embryonic pancreatic progenitors. This research was supported by Ministerio de Ciencia, Innovación y Universidades (SAF2015-73226-JIN [Agencia Estatal de Investigación {AEI}/European Regional Development Fund, European Union {UE}] and RYC-2017-21950 [AEI/European Social Fund, UE] to M.R., and BFU2014-54284-R and RTI2018-095666-B-I00 to J.F.); the Medical Research Council (MR/L02036X/1), Wellcome Trust (WT101033), and European Research Council Advanced Grant (789055) (to J.F.); the Instituto de Salud Carlos III (CA18/00045 to J.L.M.); and a Spanish Ministry of Science, Innovation, and Universities (MCIU) fellowship (PTA2018-016371-I to M.M.). J.K.-C.'s and F.P.'s research was supported by L'Agence Nationale de la Recherche (ANR) grants, L'Institut Européen de Génomique du Diabète (EGID), ANR-10-LABX-0046, a French state fund managed by ANR under the frame program Investissements d'Avenir (I-SITE ULNE/ANR-16-IDEX-0004 ULNE to F.P.), and the European Consortium for Islet Transplantation funded by the Juvenile Diabetes Research Foundation International. Work in the Centre for Genomic Regulation was supported by the Centres de Recerca de Catalunya (CERCA) Programme, Generalitat de Catalunya, and Centro de Excelencia Severo Ochoa (SEV-2015-0510). Work at Institut d'Investigació Biomèdica de Bellvitge was supported by the CERCA Programme and Generalitat de Catalunya

Large cell carcinoma (LCC) is a rare and aggressive lung cancer subtype with poor prognosis and no targeted therapies. Tumor-associated fibroblasts (TAFs) derived from LCC tumors exhibit premature senescence, and coculture of pulmonary fibroblasts with LCC cell lines selectively induces fibroblast senescence, which in turn drives LCC cell growth and invasion. Here we identify MMP1 as overexpressed specifically in LCC cell lines, and we show that expression of MMP1 by LCC cells is necessary for induction of fibroblast senescence and consequent tumor promotion in both cell culture and mouse models. We also show that MMP1, in combination with TGF-β1, is sufficient to induce fibroblast senescence and consequent LCC promotion. Furthermore, we implicate PAR-1 and oxidative stress in MMP1/TGF-β1-induced TAF senescence. Our results establish an entirely new role for MMP1 in cancer, and support a novel therapeutic strategy in LCC based on targeting senescent TAFs., This work was further supported by grants from the Agencia Estatal de Investigaci´on (AEI/FEDER) (PI13/02368, SAF2016-79527-R and PID2019-110944RB-I00 (AEI/ 10.13039/501100011033) to JA, PI16/ 00890 to NR), Fundaci´o Privada Cellex (to JA), National Institutes of Health (grant R01 GM132100 to ER), Generalitat de Catalunya (AGAUR SGR661 and CERCA Programme to JA), Junta Provincial de Barcelona de l’Associaci´o Espanyola Contra el C`ancer (AECC-B16-917 to JA), Italian Ministry of Health (RF-2016-02362946 to LR), Italian Association for Cancer Research (AIRC-IG21431 to LR), Sociedad Espa˜nola de Neumología y Cirugía Tor´acica – SEPAR (SEPAR 437 to NR), COST Action (PROTEOSTASIS BM1307), and by fellowships from Ciˆencia sem Fronteiras CNPq (to RI), and Universitat de Barcelona/beca APIF (to PD).

Decellularization; Ocular progenitors; Retina Descelularización; Progenitores oculares; Retina Descel·lularització; Progenitors oculars; Retina The retinal extracellular matrix (ECM) provides architectural support, adhesion and signal guidance that controls retinal development. Decellularization of the ECM affords great potential to tissue engineering; however, how structural retinal ECM affects in vitro development, differentiation and maturation of ocular cells remains to be elucidated. Here, mouse and porcine retinas were decellularized and the protein profile analyzed. Acellular retinal ECM (arECM) scaffolds were then repopulated with human iPSC-derived retinal pigment epithelial (RPE) cells or ocular progenitor cells (OPC) to assess their integration, proliferation and organization. 3837 and 2612 unique proteins were identified in mouse and porcine arECM, respectively, of which 93 and 116 proteins belong to the matrisome. GO analysis shows that matrisome-related proteins were associated with the extracellular region and cell junction and KEGG pathways related to signalling transduction, nervous and endocrine systems and cell junctions were enriched. Interestingly, mouse and porcine arECMs were successfully repopulated with both RPE and OPC, the latter exhibiting cell lineage-specific clusters. Retinal cells organized into different layers containing well-defined areas with pigmented cells, photoreceptors, Müller glia, astrocytes, and ganglion cells, whereas in other areas, conjunctival/limbal, corneal and lens cells re-arranged in cell-specific self-organized areas. In conclusion, our results demonstrated that decellularization of both mouse and porcine retinas retains common native ECM components that upon cell repopulation could guide similar ocular cell adhesion, migration and organization. This work was supported by La Marató de TV3 Foundation (484/C/2012); ERA-NET EuroNanoMed III-AC19/00080/ISCIII (CELLUX); Instituto de Salud Carlos III (CA18/00045 and PI18/00219); and the European Social Fund, the Ministerio de Ciencia, Innovación y Universidades, which is part of the Agencia Estatal de Investigación (PTA2018-016371-I). A.D. was supported by PT13/0001/0041 PRB2-ISCIII-SGEFI-FEDER-PE I+D+i 2013–2016 and ISCIII-FEDER RETICS (Oftared; RD16/0008). We thank the CERCA Programme/Generalitat de Catalunya for institutional support.

Large cell carcinoma (LCC) is an aggressive lung cancer subtype with poor prognosis and no targeted therapies. We previously reported that tumor-associated fibroblasts (TAFs) derived from LCC tumors exhibit premature senescence, and coculture of pulmonary fibroblasts with LCC cell lines selectively induces fibroblast senescence, which in turn drives LCC cell growth and invasion. Here we report that MMP1 is overexpressed specifically in LCC cell lines. Notably, silencing MMP1 expression in LCC cancer cell lines using shRNA revealed that MMP1 expression by LCC cells is necessary for induction of fibroblast senescence in coculture experiments with normal pulmonary fibroblasts, as revealed by the analysis of a panel of standard senescence markers, including β-galactosidase (SA-βgal) staining, permanent growth arrest and expression of senescence-associated secretory factors. Injecting control (shScr) or shMMP1 LCC cells into immunodeficient nude mice revealed that tumor growth, tumor take and cancer cell dissemination to the lung were reduced in shMMP1 H460 tumors compared to control tumors. We also observed fewer senescent fibroblasts in tumors from shMMP1 H460 cells using Sentragor staining, which allows identification of senescent cells in paraffin embedded tissues. Moreover, we found that recombinant active MMP1 in combination with TGF-β1 were sufficient to induce normal fibroblast senescence. In terms of the potential underlying mechanisms, treatment with the antioxidant n-acetyl cysteine (NAC) significantly attenuated the increase in SA-βgal+ fibroblasts elicited by co-stimulation with rMMP1 and TGF-β1, and its corresponding conditioned medium elicited a significantly lower growth and invasion in LCC cancer cells, revealing the oxidative stress implication in fibroblast senescence induction and associated pro-tumorigenic secretome. In summary, our results establish a new role for MMP1 in cancer and support that LCC cells elicit a tumor-supporting niche through the aberrant secretion of MMP1 and TGF-β1 to induce senescence in adjacent fibroblasts. Furthermore, we implicate oxidative stress in MMP1/TGF-β1-induced TAF senescence and support a novel therapeutic strategy in LCC based on targeting senescent TAFs. Citation Format: Marta Gabasa, Evette S. Radisky, Rafael Ikemori, Giulia Bertolini, Marselina Arshakyan, Alexandra Hockla, Paula Duch, Ornella Rondinone, Alejandro Llorente, Maria Maqueda, Alexandre Perera, Noemí Reguart, Luca Roz, Derek C. Radisky, Jordi Alcaraz. MMP1 and TGF-β1 cooperate to drive tumor progression in large cell carcinoma of the lung through fibroblast senescence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2515.

Gene expression (GE) analyses on blood samples from marathon and half-marathon runners have reported significant impacts on the immune and inflammatory systems. An ultra-marathon trail (UMT) represents a greater effort due to its more testing conditions. For the first time, we report the genome-wide GE profiling in a group of 16 runners participating in an 82 km UMT competition. We quantified their differential GE profile before and after the race using HuGene2.0st microarrays (Affymetrix Inc., California, US). The results obtained were decomposed by means of an independent component analysis (ICA) targeting independent expression modes. We observed significant differences in the expression levels of 5,084 protein coding genes resulting in an overrepresentation of 14% of the human biological pathways from the Kyoto Encyclopedia of Genes and Genomes database. These were mainly clustered on terms related with protein synthesis repression, altered immune system and infectious diseases related mechanisms. In a second analysis, 27 out of the 196 transcriptional regulators (TRs) included in the Open Regulatory Annotation database were overrepresented. Among these TRs, we identified transcription factors from the hypoxia-inducible factors (HIF) family EPAS1 (p< 0.01) and HIF1A (p

There is growing interest in defining the aberrant molecular differences between normal and tumor-associated fibroblasts (TAFs) that support tumor progression. For this purpose, we recently conducted a genome-wide DNA methylation profiling of TAFs and paired control fibroblasts (CFs) from non-small cell lung cancer (NSCLC) patients, and reported a widespread hypomethylation concomitantly with focal gain of DNA methylation; in addition, we found evidence that a fraction of lung TAFs are fibrocytes in origin. Of note, the aberrant epigenome of lung TAFs had a global impact in gene expression and a selective impact on the TGF-β pathway. To get insights on the functional implications of the latter impact, we analyzed the response of lung TAFs to exogenous TGF-β1 in terms of activation and contractility. We found a larger expression of a panel of activation markers including α-SMA and collagen-I in TAFs compared to control fibroblasts. Likewise, TGF-β1 elicited a larger contractility in TAFs than in CFs as assessed by traction force microscopy. These findings reveal that lung TAFs are hyperresponsive to TGF-β1, which may underlie the expansion and/or maintenance of the tumor-promoting desmoplastic stroma in lung cancer. Citation Format: Miguel Vizoso, Marta Puig, F. Javier Carmona, María Maqueda, Antonio Gomez, Anna Labernardie, Marta Gabasa, Saioa Mendizuri, Rafael Ikemori, Xavier Trepat, Sebastian Moran, Enrique Vidal, Noemí Reguart, Alexandre Perera, Manel Esteller, Jordi Alcaraz. DNA methylation profiling unveils TGF-β hyperresponse in tumor associated fibroblasts from lung cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2763.

The objective of this chapter is to identify and characterise measures for the abatement of NOx and NMVOC, which are currently available and likely to become instrumental in the period until 2010.