190 research outputs found

    The Environment and Directed Technical Change: Comment

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    This paper discusses the growth model with environmental constraints recently presented in (Acemoglu et al., 2011) which focuses on the redirection of technical change by climate policies with research subsidies and a carbon tax. First, Acemoglu et al.'s model and chosen parameters yield numerical results that do not support the conclusion that ambitious climate policies can be conducted “without sacrificing (much or any) long-run growth”. Second, they select unrealistic key parameters for carbon sinks and elasticity of substitution. We find that more realistic parameters lead to very different results. Third, the model leads to an unrealistic conclusion when used to analyse endogenous growth, suggesting specification problems.Technological Change, Endogenous Growth, Climate, Energy Substitutability

    The environment and directed technical change : comment

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    This paper discusses the growth model with environmental constraints recently presented in (Acemoglu et al., 2011) which focuses on the redirection of technical change by climate policies with research subsidies and a carbon tax. First, Acemoglu et al.'s model and chosen parameters yield numerical results that do not support the conclusion that ambitious climate policies can be conducted " without sacrificing (much or any) long-run growth ". Second, they select unrealistic key parameters for carbon sinks and elasticity of substitution. We find that more realistic parameters lead to very different results. Third, the model leads to an unrealistic conclusion when used to analyse endogenous growth, suggesting specification problems.Cet article analyse le modèle de croissance sous contraintes environnementales présenté par Acemoglu et al. (2011), lequel met l'accent sur la réorientation du changement technique au moyen de politiques climatiques combinant une taxe carbone et des subventions à la recherche. En premier lieu, le modèle de Acemoglu et al.'s avec les paramètres retenus fait ressortir des résultats numériques qui ne soutiennent nullement la conclusion selon laquelle des politiques climatiques ambitieuses peuvent être conduites " sans (guère ou pas du tout) sacrifier la croissance de long terme ". Par ailleurs, Acemoglu et al. ont choisi des valeurs irréalistes pour des paramètres cruciaux comme les puits de carbone ou l'élasticité de substitution. Des valeurs plus réalistes donnent des résultats très différents. En troisième lieu, utilisé pour analyser la croissance endogène, le modèle aboutit à des incohérences, ce qui suggère des problèmes de spécification

    Auditorio «Maurice Ravel» Lyon – Francia

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    Shaped like a St. Jacques shell, the «Maurice Ravel» Auditorium has a capacity for over 2000 people with excellent acoustic and comfort conditions. This was, precisely, one of the main problems the architects had to solve: creating an atmosphere, a climate of musical receptivity, without sacrificing the technical acoustic and visibility requirements or the need to contain differently sized musical groups. The Auditorium consists of the audience hall, the stage, the orchestra pit, the lobby, sitting rooms and is completed by two annexes, the first, used for orchestra rehearsals and the second, a L-shaped, three storied building containing artists' apartments, camerinos, administration services and mechanical rooms.Con su forma-de concha de Santiago, el Auditorio «Maurice Ravel» ofrece capacidad para más de 2.000 personas en inmejorables condiciones acústicas y de confort. Este fue, precisamente, uno de los principales problemas que tuvieron que resolver los arquitectos: crear un ambiente y un clima de receptividad musical, sin sacrificar los imperativos técnicos debidos a la acústica, a la visibilidad y a las exigencias de dar cabida a formaciones musicales de diversa importancia. El auditorio, compuesto por la sala del público, el plato, el foso de la orquesta, el vestíbulo de entrada y los salones de descanso, se completó con dos anexos: el primero destinado a sala de ensayos para la orquesta; y el segundo, en forma de «L» y con tres niveles de altura, que alberga los alojamientos de artistas, vestuarios, servicios administrativos y los locales técnicos y de servicios

    Periostin in lymph node pre-metastatic niches governs lymphatic endothelial cell functions and metastatic colonization.

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    peer reviewedAlthough lymph node (LN) metastasis is an important prognostic parameter in cervical cancer, the tissue remodeling at a pre-metastatic state is poorly documented in LNs. We here identified periostin (POSTN) as a component of non-metastatic LNs by applying proteomic analyses and computerized image quantifications on LNs of patients with cervical cancer. We provide evidence for remarkable modifications of POSTN and lymphatic vessel distributions and densities in non-metastatic sentinel and metastatic human LNs, when compared to distant non-metastatic LNs. POSTN deposition at a pre-metastatic stage was demonstrated in a pre-clinical murine model (the ear sponge assay). Its expression by fibroblastic LN cells was assessed by in situ hybridization and in vitro cultures. In vitro, POSTN promoted lymphatic endothelial cell functions and tumor cell proliferation. Accordingly, the in vivo injection of recombinant POSTN together with VEGF-C boosted the lymphangiogenic response, while the metastatic potential of tumor cells was drastically reduced using a POSTN blocking antibody. This translational study also supports the existence of an unprecedented dialog "in cascade", between the primary tumor and the first pelvic nodal relay in early cervical cancer, and subsequently from pelvic LN to para-aortic LNs in locally advanced cervical cancers. Collectively, this work highlights the association of POSTN deposition with lymphangiogenesis in LNs, and provides evidence for a key contribution of POSTN in promoting VEGF-C driven lymphangiogenesis and the seeding of metastatic cells

    The role of microRNA-155/liver X receptor pathway in experimental and idiopathic pulmonary fibrosis

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    Background: Idiopathic Pulmonary Fibrosis (IPF) is progressive and rapidly fatal. Improved understanding of pathogenesis is required to prosper novel therapeutics. Epigenetic changes contribute to IPF therefore microRNAs may reveal novel pathogenic pathways. Objectives: To determine the regulatory role of microRNA(miR)-155 in the pro-fibrotic function of murine lung macrophages and fibroblasts, IPF lung fibroblasts and its contribution to experimental pulmonary fibrosis. Methods: Bleomycin-induced lung fibrosis in wild-type and miR-155-/- mice was analyzed by histology, collagen and pro-fibrotic gene expression. Mechanisms were identified by in silico and molecular approaches; validated in mouse lung fibroblasts and macrophages, and in IPF lung fibroblasts, using loss-and-gain of function assays, and in vivo using specific inhibitors. Results: miR-155-/- mice developed exacerbated lung fibrosis, increased collagen deposition, collagen 1 and 3 mRNA expression, TGFβ production, and activation of alternatively-activated macrophages, contributed by deregulation of the microRNA-155 target gene the liver X receptor (LXR)α in lung fibroblasts and macrophages. Inhibition of LXRα in experimental lung fibrosis and in IPF lung fibroblasts reduced the exacerbated fibrotic response. Similarly, enforced expression of miR-155 reduced the pro-fibrotic phenotype of IPF and miR-155-/- fibroblasts. Conclusion: We describe herein a molecular pathway comprising miR-155 and its epigenetic LXRα target that when deregulated enables pathogenic pulmonary fibrosis. Manipulation of the miR-155/LXR pathway may have therapeutic potential for IPF

    Tumor resistance to ferroptosis driven by Stearoyl-CoA Desaturase-1 (SCD1) in cancer cells and Fatty Acid Biding Protein-4 (FABP4) in tumor microenvironment promote tumor recurrence.

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    PROBLEM: Tumor recurrence is a major clinical issue that represents the principal cause of cancer-related deaths, with few targetable common pathways. Mechanisms by which residual tumors persist and progress under a continuous shift between hypoxia-reoxygenation after neoadjuvent-therapy are unknown. In this study, we investigated the role of lipid metabolism and tumor redox balance in tumor recurrence. METHODS: Lipidomics, proteomics and mass spectrometry imaging approaches where applied to mouse tumor models of recurrence. Genetic and pharmacological inhibitions of lipid mediators in tumors were used in vivo and in functional assays in vitro. RESULTS: We found that stearoyl-CoA desaturase-1 (SCD1) expressed by cancer cells and fatty acid binding protein-4 (FABP4) produced by tumor endothelial cells (TECs) and adipocytes in the tumor microenvironment (TME) are essential for tumor relapse in response to tyrosine kinase inhibitors (TKI) and chemotherapy. SCD1 and FABP4 were also found upregulated in recurrent human breast cancer samples and correlated with worse prognosis of cancer patients with different types of tumors. Mechanistically, SCD1 leads to fatty acid (FA) desaturation and FABP4 derived from TEM enhances lipid droplet (LD) in cancer cells, which cooperatively protect from oxidative stress-induced ferroptosis. We revealed that lipid mobilization and desaturation elicit tumor intrinsic antioxidant and anti-ferroptotic resources for survival and regrowth in a harsh TME. Inhibition of lipid transport from TME by FABP4 inhibitor reduced tumor regrowth and by genetic - or by pharmacological - targeting SCD1 in vivo, tumor regrowth was abolished completely. CONCLUSION: This finding unveils that it is worth taking advantage of tumor lipid addiction, as a tumor vulnerability to design novel treatment strategy to prevent cancer recurrence

    A candidate regulatory variant at the TREM gene cluster associates with decreased Alzheimer's disease risk and increased TREML1 and TREM2 brain gene expression

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    Introduction: We hypothesized that common Alzheimer's disease (AD)-associated variants within the triggering receptor expressed on myeloid (TREM) gene cluster influence disease through gene expression. Methods: Expression microarrays on temporal cortex and cerebellum from ∼400 neuropathologically diagnosed subjects and two independent RNAseq replication cohorts were used for expression quantitative trait locus analysis. Results: A variant within a DNase hypersensitive site 5′ of TREM2, rs9357347-C, associates with reduced AD risk and increased TREML1 and TREM2 levels (uncorrected P = 6.3 × 10−3 and 4.6 × 10−2, respectively). Meta-analysis on expression quantitative trait locus results from three independent data sets (n = 1006) confirmed these associations (uncorrected P = 3.4 × 10−2 and 3.5 × 10−3, Bonferroni-corrected P = 6.7 × 10−2 and 7.1 × 10−3, respectively). Discussion: Our findings point to rs9357347 as a functional regulatory variant that contributes to a protective effect observed at the TREM locus in the International Genomics of Alzheimer's Project genome-wide association study meta-analysis and suggest concomitant increase in TREML1 and TREM2 brain levels as a potential mechanism for protection from AD

    NALP3 inflammasome upregulation and CASP1 cleavage of the glucocorticoid receptor cause glucocorticoid resistance in leukemia cells

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    Glucocorticoids are universally used in the treatment of acute lymphoblastic leukemia (ALL), and resistance to glucocorticoids in leukemia cells confers poor prognosis. To elucidate mechanisms of glucocorticoid resistance, we determined the prednisolone sensitivity of primary leukemia cells from 444 patients newly diagnosed with ALL and found significantly higher expression of CASP1 (encoding caspase 1) and its activator NLRP3 in glucocorticoid-resistant leukemia cells, resulting from significantly lower somatic methylation of the CASP1 and NLRP3 promoters. Overexpression of CASP1 resulted in cleavage of the glucocorticoid receptor, diminished the glucocorticoid-induced transcriptional response and increased glucocorticoid resistance. Knockdown or inhibition of CASP1 significantly increased glucocorticoid receptor levels and mitigated glucocorticoid resistance in CASP1-overexpressing ALL. Our findings establish a new mechanism by which the NLRP3-CASP1 inflammasome modulates cellular levels of the glucocorticoid receptor and diminishes cell sensitivity to glucocorticoids. The broad impact on the glucocorticoid transcriptional response suggests that this mechanism could also modify glucocorticoid effects in other diseases

    Genome-wide analyses as part of the international FTLD-TDP whole-genome sequencing consortium reveals novel disease risk factors and increases support for immune dysfunction in FTLD

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    Frontotemporal lobar degeneration with neuronal inclusions of the TAR DNA-binding protein 43 (FTLD-TDP) represents the most common pathological subtype of FTLD. We established the international FTLD-TDP whole genome sequencing consortium to thoroughly characterize the known genetic causes of FTLD-TDP and identify novel genetic risk factors. Through the study of 1,131 unrelated Caucasian patients, we estimated that C9orf72 repeat expansions and GRN loss-of-function mutations account for 25.5% and 13.9% of FTLD-TDP patients, respectively. Mutations in TBK1 (1.5%) and other known FTLD genes (1.4%) were rare, and the disease in 57.7% of FTLD-TDP patients was unexplained by the known FTLD genes. To unravel the contribution of common genetic factors to the FTLD-TDP etiology in these patients, we conducted a two-stage association study comprising the analysis of whole-genome sequencing data from 517 FTLD-TDP patients and 838 controls, followed by targeted genotyping of the most associated genomic loci in 119 additional FTLD-TDP patients and 1653 controls. We identified three genome-wide significant FTLD-TDP risk loci: one new locus at chromosome 7q36 within the DPP6 gene led by rs118113626 (pvalue=4.82e-08, OR=2.12), and two known loci: UNC13A, led by rs1297319 (pvalue=1.27e-08, OR=1.50) and HLA-DQA2 led by rs17219281 (pvalue=3.22e-08, OR=1.98). While HLA represents a locus previously implicated in clinical FTLD and related neurodegenerative disorders, the association signal in our study is independent from previously reported associations. Through inspection of our whole genome sequence data for genes with an excess of rare loss-of-function variants in FTLD-TDP patients (n≥3) as compared to controls (n=0), we further discovered a possible role for genes functioning within the TBK1-related immune pathway (e.g. DHX58, TRIM21, IRF7) in the genetic etiology of FTLD-TDP. Together, our study based on the largest cohort of unrelated FTLD-TDP patients assembled to date provides a comprehensive view of the genetic landscape of FTLD-TDP, nominates novel FTLD-TDP risk loci, and strongly implicates the immune pathway in FTLD-TDP pathogenesis
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