Distinct Roles of Candida albicans Drug Resistance Transcription Factors TAC1, MRR1, and UPC2 in Virulence.

Azoles are widely used in antifungal therapy in medicine. Resistance to azoles can occur in Candida albicans principally by overexpression of multidrug transporter gene CDR1, CDR2, or MDR1 or by overexpression of ERG11, which encodes the azole target. The expression of these genes is controlled by the transcription factors (TFs) TAC1 (involved in the control of CDR1 and CDR2), MRR1 (involved in the control of MDR1), and UPC2 (involved in the control of ERG11). Several gain-of-function (GOF) mutations are present in hyperactive alleles of these TFs, resulting in the overexpression of target genes. While these mutations are beneficial to C. albicans survival in the presence of the antifungal drugs, their effects could potentially alter the fitness and virulence of C. albicans in the absence of the selective drug pressure. In this work, the effect of GOF mutations on C. albicans virulence was addressed in a systemic model of intravenous infection by mouse survival and kidney fungal burden assays. We engineered a set of strains with identical genetic backgrounds in which hyperactive alleles were reintroduced in one or two copies at their genomic loci. The results obtained showed that neither TAC1 nor MRR1 GOF mutations had a significant effect on C. albicans virulence. In contrast, the presence of two hyperactive UPC2 alleles in C. albicans resulted in a significant decrease in virulence, correlating with diminished kidney colonization compared to that by the wild type. In agreement with the effect on virulence, the decreased fitness of an isolate with UPC2 hyperactive alleles was observed in competition experiments with the wild type in vivo but not in vitro. Interestingly, UPC2 hyperactivity delayed filamentation of C. albicans after phagocytosis by murine macrophages, which may at least partially explain the virulence defects. Combining the UPC2 GOF mutation with another hyperactive TF did not compensate for the negative effect of UPC2 on virulence. In conclusion, among the major TFs involved in azole resistance, only UPC2 had a negative impact on virulence and fitness, which may therefore have consequences for the epidemiology of antifungal resistance.

Defective tumor necrosis factor-alpha-dependent control of astrocyte glutamate release in a transgenic mouse model of Alzheimer disease.

The cytokine tumor necrosis factor-alpha (TNFalpha) induces Ca2+-dependent glutamate release from astrocytes via the downstream action of prostaglandin (PG) E2. By this process, astrocytes may participate in intercellular communication and neuromodulation. Acute inflammation in vitro, induced by adding reactive microglia to astrocyte cultures, enhances TNFalpha production and amplifies glutamate release, switching the pathway into a neurodamaging cascade (Bezzi, P., Domercq, M., Brambilla, L., Galli, R., Schols, D., De Clercq, E., Vescovi, A., Bagetta, G., Kollias, G., Meldolesi, J., and Volterra, A. (2001) Nat. Neurosci. 4, 702-710). Because glial inflammation is a component of Alzheimer disease (AD) and TNFalpha is overexpressed in AD brains, we investigated possible alterations of the cytokine-dependent pathway in PDAPP mice, a transgenic model of AD. Glutamate release was measured in acute hippocampal and cerebellar slices from mice at early (4-month-old) and late (12-month-old) disease stages in comparison with age-matched controls. Surprisingly, TNFalpha-evoked glutamate release, normal in 4-month-old PDAPP mice, was dramatically reduced in the hippocampus of 12-month-old animals. This defect correlated with the presence of numerous beta-amyloid deposits and hypertrophic astrocytes. In contrast, release was normal in cerebellum, a region devoid of beta-amyloid deposition and astrocytosis. The Ca2+-dependent process by which TNFalpha evokes glutamate release in acute slices is distinct from synaptic release and displays properties identical to those observed in cultured astrocytes, notably PG dependence. However, prostaglandin E2 induced normal glutamate release responses in 12-month-old PDAPP mice, suggesting that the pathology-associated defect involves the TNFalpha-dependent control of secretion rather than the secretory process itself. Reduced expression of DENN/MADD, a mediator of TNFalpha-PG coupling, might account for the defect. Alteration of this neuromodulatory astrocytic pathway is described here for the first time in relation to Alzheimer disease.

Hematopoietic stem cell transplantation in Switzerland: a comprehensive quality control report on centre effect.

Interest groups advocate centre-specific outcome data as a useful tool for patients in choosing a hospital for their treatment and for decision-making by politicians and the insurance industry. Haematopoietic stem cell transplantation (HSCT) requires significant infrastructure and represents a cost-intensive procedure. It therefore qualifies as a prime target for such a policy. We made use of the comprehensive database of the Swiss Blood Stem Cells Transplant Group (SBST) to evaluate potential use of mortality rates. Nine institutions reported a total of 4717 HSCT - 1427 allogeneic (30.3%), 3290 autologous (69.7%) - in 3808 patients between the years 1997 and 2008. Data were analysed for survival- and transplantation-related mortality (TRM) at day 100 and at 5 years. The data showed marked and significant differences between centres in unadjusted analyses. These differences were absent or marginal when the results were adjusted for disease, year of transplant and the EBMT risk score (a score incorporating patient age, disease stage, time interval between diagnosis and transplantation, and, for allogeneic transplants, donor type and donor-recipient gender combination) in a multivariable analysis. These data indicate comparable quality among centres in Switzerland. They show that comparison of crude centre-specific outcome data without adjustment for the patient mix may be misleading. Mandatory data collection and systematic review of all cases within a comprehensive quality management system might, in contrast, serve as a model to ascertain the quality of other cost-intensive therapies in Switzerland.

Metabolic predictors of obesity. Contribution of resting energy expenditure, thermic effect of food, and fuel utilization to four-year weight gain of post-obese and never-obese women.

This prospective study was designed to identify abnormalities of energy expenditure and fuel utilization which distinguish post-obese women from never-obese controls. 24 moderately obese, postmenopausal, nondiabetic women with a familial predisposition to obesity underwent assessments of body composition, fasting and postprandial energy expenditure, and fuel utilization in the obese state and after weight loss (mean 12.9 kg) to a post-obese, normal-weight state. The post-obese women were compared with 24 never-obese women of comparable age and body composition. Four years later, without intervention, body weight was reassessed in both groups. Results indicated that all parameters measured in the post-obese women were similar to the never-obese controls: mean resting energy expenditure, thermic effect of food, and fasting and postprandial substrate oxidation and insulin-glucose patterns. Four years later, post-obese women regained a mean of 10.9 kg while control subjects remained lean (mean gain 1.7 kg) (P < 0.001 between groups). Neither energy expenditure nor fuel oxidation correlated with 4-yr weight changes, whereas self-reported physical inactivity was associated with greater weight regain. The data suggest that weight gain in obesity-prone women may be due to maladaptive responses to the environment, such as physical inactivity or excess energy intake, rather than to reduced energy requirements.

Tumor-host interactions Part 1: Stromal signatures of breast and prostate cancer Part 2: GLG1 and the control of the secretory pathway in tumor cells

Tumor-host interaction is a key determinant during cancer progression, from primary tumor growth to metastatic dissemination. At each step, tumor cells have to adapt to and subvert different types of microenvironment, leading to major phenotypic and genotypic alterations that affect both tumor and surrounding stromal compartments. Understanding the molecular mechanisms that govern tumor-host interplay may be essential for better comprehension of tumorigenesis in an effort to improve current anti-cancer therapies. The present work is composed of two projects that address tumor-host interactions from two different perspectives, the first focusing on the characterization of tumor-associated stroma and the second on membrane trafficking in tumor cells. Part 1. To selectively address stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to analyze the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Comparison showed that invasive breast and prostate cancer elicit distinct, tumor-specific stromal responses, with a limited panel of shared induced and/or repressed genes. Both breast and prostate tumor-specific deregulated stromal gene sets displayed statistically significant survival-predictive ability for their respective tumor type. By contrast, a stromal gene signature common to both tumor types did not display prognostic value, although expression of two individual genes within this common signature was found to be associated with patient survival. Part 2. GLG1 is known as an E-selectin ligand and an intracellular FGF receptor, depending on cell type and context. Immunohistochemical and immunofluorescence analyses showed that GLG1 is primarily localized in the Golgi of human tumor cells, a central location in the biosynthetic/secretory pathways. GLG1 has been shown to interact with and to recruit the ARF GEF BIGI to the Golgi membrane. Depletion of GLG1 or BIGI markedly reduced ARF3 membrane localization and activation, and altered the Golgi structure. Interestingly, these perturbations did not impair constitutive secretion in general, but rather seemed to impair secretion of a specific subset of proteins that includes MMP-9. Thus, GLG1 coordinates ARF3 activation by recruiting BIGI to the Golgi membrane, thereby affecting secretion of specific molecules. - Les interactions tumeur-hôte constituent un élément essentiel à la progression tumorale, de la croissance de la tumeur primaire à la dissémination des métastases. A chaque étape, les cellules tumorales doivent s'adapter à différents types de microenvironnement et les détourner à leur propre avantage, donnant lieu à des altérations phénotypiques et génotypiques majeures qui affectent aussi bien la tumeur elle-même que le compartiment stromal environnant. L'étude des mécanismes moléculaires qui régissent les interactions tumeur-hôte constitue une étape essentielle pour une meilleure compréhension du processus de tumorigenèse dans le but d'améliorer les thérapies anti cancer existantes. Le travail présenté ici est composé de deux projets qui abordent la problématique des interactions tumeur-hôte selon différentes perspectives, le premier se concentrant sur la caractérisation du stroma tumoral et le second sur le trafic intracellulaire des cellules tumorales. Partie 1. Pour examiner les changements d'expression des gènes dans le stroma en réponse à la progression du cancer, des puces à ADN Affymetrix ont été utilisées afin d'analyser les transcriptomes des cellules stromales issues de carcinomes invasifs du sein et de la prostate et collectées par microdissection au laser. L'analyse comparative a montré que les cancers invasifs du sein et de la prostate provoquent des réponses stromales spécifiques à chaque type de tumeur, et présentent peu de gènes induits ou réprimés de façon similaire. L'ensemble des gènes dérégulés dans le stroma associé au cancer du sein, ou à celui de la prostate, présente une valeur pronostique pour les patients atteints d'un cancer du sein, respectivement de la prostate. En revanche, la signature stromale commune aux deux types de cancer n'a aucune valeur prédictive, malgré le fait que l'expression de deux gènes présents dans cette liste soit liée à la survie des patients. Partie 2. GLG1 est connu comme un ligand des sélectines E ainsi que comme récepteur intracellulaire pour des facteurs de croissances FGFs selon le type de cellule dans lequel il est exprimé. Des analyses immunohistochimiques et d'immunofluorescence ont montré que dans les cellules tumorales, GLG1 est principalement localisé au niveau de l'appareil de Golgi, une place centrale dans la voie biosynthétique et sécrétoire. Nous avons montré que GLG1 interagit avec la protéine BIGI et participe à son recrutement à la membrane du Golgi. L'absence de GLG1 ou de BIGI réduit drastiquement le pool d'ARF3 associé aux membranes ainsi que la quantité d'ARF3 activés, et modifie la structure de l'appareil de Golgi. Il est particulièrement intéressant de constater que ces perturbations n'ont pas d'effet sur la sécrétion constitutive en général, mais semblent plutôt affecter la sécrétion spécifique d'un sous-groupe défini de protéines comprenant MMP-9. GLG1 coordonne donc l'activation de ARF3 en recrutant BIGI à la membrane du Golgi, agissant par ce moyen sur la sécrétion de molécules spécifiques.

Cognitive behavioural therapy for weight gain associated with antipsychotic drugs

BACKGROUND: Overweight and obesity are common concerns in individuals with severe mental disorders. In particular, antipsychotic drugs (AP) frequently induce weight gain. This phenomenon lacks current management and no previous controlled studies seem to use cognitive therapy to modify eating and weight-related cognitions. Moreover, none of these studies considered binge eating or eating and weight-related cognitions as possible outcomes. AIM: The main aim of this study is to assess the effectivity of cognitive and behavioural treatment (CBT) on eating and weight-related cognitions, binge eating symptomatology and weight loss in patients who reported weight gain during AP treatment. METHOD: A randomized controlled study (12-week CBT vs. Brief Nutritional Education) was carried out on 61 patients treated with an antipsychotic drug who reported weight gain following treatment. Binge eating symptomatology, eating and weight-related cognitions, as well as weight and body mass index were assessed before treatment, at 12 weeks and at 24 weeks. RESULTS: The CBT group showed some improvement with respect to binge eating symptomatology and weight-related cognitions, whereas the control group did not. Weight loss occurred more progressively and was greater in the CBT group at 24 weeks. CONCLUSION: The proposed CBT treatment is particularly interesting for patients suffering from weight gain associated with antipsychotic treatment

Increased fat oxidation in prepubertal obese children: a metabolic defense against further weight gain?

The purpose of this study was to measure postabsorptive fat oxidation at rest and to assess the association between fat mass and fat oxidation rate in prepubertal children, who were assigned to two groups: 35 obese children (weight, 44.5 +/- 9.7 kg; fat mass; 31.7 +/- 5.4%) and 37 nonobese children (weight, 30.8 +/- 6.8 kg; fat mass, 17.5 +/- 6.7%). Postabsorptive fat oxidation expressed in absolute value was significantly higher in obese than in nonobese children (31.4 +/- 9.7 mg/min vs 21.9 +/- 10.2 mg/min; p < 0.001) but not when adjusted for fat-free mass by analysis of covariance with fat-free mass as the covariate (28.2 +/- 10.6 mg/min vs 24.9 +/- 10.5 mg/min). In obese children and in the total group, fat mass and fat oxidation were significantly correlated (r = 0.65; p < 0.001). The slope of the relationship indicated that for each 10 kg additional fat mass, resting fat oxidation increased by 18 gm/day. We conclude that obese prepubertal children have a higher postabsorptive rate of fat oxidation than nonobese children. This metabolic process may favor the achievement of a new equilibrium in fat balance, opposing further adipose tissue gain.

Image quality assessment in digital mammography: part II. NPWE as a validated alternative for contrast detail analysis.

Assessment of image quality for digital x-ray mammography systems used in European screening programs relies mainly on contrast-detail CDMAM phantom scoring and requires the acquisition and analysis of many images in order to reduce variability in threshold detectability. Part II of this study proposes an alternative method based on the detectability index (d') calculated for a non-prewhitened model observer with an eye filter (NPWE). The detectability index was calculated from the normalized noise power spectrum and image contrast, both measured from an image of a 5 cm poly(methyl methacrylate) phantom containing a 0.2 mm thick aluminium square, and the pre-sampling modulation transfer function. This was performed as a function of air kerma at the detector for 11 different digital mammography systems. These calculated d' values were compared against threshold gold thickness (T) results measured with the CDMAM test object and against derived theoretical relationships. A simple relationship was found between T and d', as a function of detector air kerma; a linear relationship was found between d' and contrast-to-noise ratio. The values of threshold thickness used to specify acceptable performance in the European Guidelines for 0.10 and 0.25 mm diameter discs were equivalent to threshold calculated detectability indices of 1.05 and 6.30, respectively. The NPWE method is a validated alternative to CDMAM scoring for use in the image quality specification, quality control and optimization of digital x-ray systems for screening mammography.

The early IL-4 response to Leishmania major responsible for progressive disease in BALB/c mice is subject to the control of autocrine IL-2 production and regulatory CD4+C25+ T cells

Résumé : La majorité des souches de souris de laboratoire sont résistantes à l'infection par le parasite Leishmania major (L. major). A l'opposé, les souris de la souche BALB développent une maladie évolutive. La résistance et la sensibilité sont corrélées avec l'apparition de lymphocytes T CD4+ spécifiques du parasite, Th1 (de l'anglais T helper) ou Th2 respectivement. La réponse aberrante Th2 chez les souris de la souche BALB/c dépend, au moins en partie, de façon critique de la production rapide d'IL-4 suite à l'infection. Ce pic précoce d'IL-4 est produit par une population de lymphocytes T CD4+ restreinte aux molécules du MHC de classe II, exprimant les chaînes du récepteur des cellules T Vß4-Va8. Ces lymphocytes sont spécifiques d'un épitope de l'homologue Leishmania de la molécule RACK1 des mammifères, appelée LACK. Il a été clairement démontré que l'IL-4 rapidement produite par ces cellules T CD4+ Vß4-Va8 induit la maturation Th2 responsable de la sensibilité vis-à-vis de L. major. Des expériences ont été entreprises pour étudier la régulation de cette réponse précoce d'IL-4. Dans ce travail, nous avons documenté, dans les cellules provenant des ganglions de souris sensibles infectées par L. major, une augmentation de la transcription de l'ARNm de l'IL-2 qui précède la réponse précoce d'IL-4. La neutralisation de l'IL-2 durant les premiers jours d'infection induit la maturation des cellules Thl et la résistance vis-à-vis de L. major. Ces effets de l'anticorps anti-IL-2 neutralisant sont liés à sa capacité d'interférer avec la transcription rapide d'IL-4 des cellules CD4+ réactives à l'antigène LACK. Une augmentation similaire d'IL-2 survient chez les souris résistantes C57BL/6 qui sont incapables de générer la réponse précoce d'IL-4. Cependant, la protéiné LACK induit une transcription précoce d'IL-2 uniquement chez les souris sensibles. Des expériences de reconstitution utilisant des souris C.B.-17 SCID et des cellules T CD4+ réactives à LACK provenant de souris BALB/c IL-2-~démontrent un mode d'action autocrine de l'IL-2 sur la régulation de la réponse précoce d'IL4. Par conséquent, chez les souris C57BL/6, l'absence du pic précoce d'ARNm de l'IL-4 important pour la progression de la maladie paraît liée à l'incapacité des cellules T CD4+ réactives à LACK de produire de l'IL-2. Un rôle dans le contrôle de la production précoce d'IL-4 par les cellules T régulatrices CD4+CD25+ a été investigué en déplétant in vivo cette population de cellules. La déplétion induit une élévation du pic précoce de l'ARNm de l'IL-4 dans les ganglions drainant de souris BALB/c, ainsi qu'une exacerbation du cours de la maladie avec des taux augmentés d'IL-4 dans les ganglions. La réponse rapide d'IL-2 vis-à-vis de L. major est aussi significativement augmentée chez les souris BALB/c déplétées en cellules CD4+CD25+. De plus, nous avons démontré que le transfert de 10puissance(7) cellules provenant de la rate de souris BALB/c déplétées en cellules T régulatrices CD4+CD25+ rend les souris SCID sensibles à l'infection et permet la différentiation Th2. Au contraire, les souris SCID reconstituées avec 10' cellules de la rate de souris BALB/c contrôle sont résistantes à infection par L. major et développent une réponse Thl. Chez les souris SCID reconstituées avec des cellules de rate déplétées en cellules exprimant le marqueur CD25, le traitement avec un anticorps neutralisant l'IL-4 au moment de l'infection par L. major prévient le développement de la réponse Th2 et rend ces souris résistantes à l'infection. Ces résultats démontrent que les cellules T régulatrices CD4+CD25+ jouent un rôle dans la régulation du pic précoce d'IL-4 responsable du développement cellulaire Th2 dans ce modèle d'infection. Summary Mice from most strains are resistant to infection with Leishmania major (L. major). In contrast, BALB mice develop progressive disease. Resistance and susceptibility result from parasite-specific CD4+ Thl or Th2 cells, respectively. The aberrant Th2 response in BALB/c mice depends, at least in part, upon the production of IL-4 early after infection. The CD4+ T cells responsible for this early IL-4 response to L. major express a restricted TCR repertoire (Vß4-Va8) and respond to an I-Ad-restricted epitope of the Leishmania homologue of mammalian RACK1, designated LACK. The role of these cells and the IL-4 they produce for subsequent Th2 cell development and disease progression in BALB/c mice was demonstrated. Experiments have been undertaken to study the regulation of the rapid IL-4 production to L. major. In this report, we document an IL-2 mRNA burst, preceding the reported early IL-4 response, in draining lymph nodes of susceptible mice infected with L. major. Neutralization of IL-2 during the first days of infection redirected Thl cell maturation and resistance to L. major, through interference with the rapid IL-4 transcription in LACKreactive CD4+ cells. A burst of IL-2 transcripts also occurred in infected C57BL/6 mice that do not mount an early IL-4 response. However, although the LACK protein induced IL-2 transcripts in susceptible mice, it failed to trigger this response in resistant C57BL/6 mice. Reconstitution experiments using C.B.-17 SCID mice and LACK-reactive CD4+ T cells from IL-2-/- BALB/c mice showed that triggering of the early IL-4 response required autocrine IL2. Thus, in C57BL/6 mice, the inability of LACK-reactive CD4+ T cells to express early IL-4 mRNA transcription, important for disease progression, appears due to an incapacity of these cells to produce IL-2. A role for CD4+CD25+ regulatory T cells in the control of this early IL-4 production was investigated by depleting in vivo this regulatory T cell population. Depletion induced an increase in the early burst of IL-4 mRNA in the draining lymph nodes of BALB/c mice, and exacerbated the course of disease with higher levels of IL-4 mRNA and protein in their lymph nodes. The rapid IL-2 response to L. major is also significantly enhanced in BALB/c mice depleted of CD4+CD25+ cells. We further showed that transfer of 10~ BALB/c spleen cells that were depleted of CD4+CD25+ regulatory T cells rendered SCID mice susceptible to infection and allowed Th2 differentiation while SCID mice reconstituted with 10 control BALB/c spleen cells were resistant to infection with L. major and developed a Thl response. Treatment with a mAb against IL-4 upon infection with L. major in SCID mice reconstituted with CD25-depleted spleen cells prevented the development of Th2 polarization and rendered them resistant to infection. These results demonstrate that CD4+CD25+ regulatory T cells play a role in regulating the early IL-4 mRNA and the subsequent development of a Th2 response in this model of infection.

A gain-of-function allele of TPC1 activates oxylipin biogenesis after leaf wounding in Arabidopsis.

Jasmonates, potent lipid mediators of defense gene expression in plants, are rapidly synthesized in response to wounding. These lipid mediators also stimulate their own production via a positive feedback circuit, which depends on both JA synthesis and JA signaling. To date, molecular components regulating the activation of jasmonate biogenesis and its feedback loop have been poorly characterized. We employed a genetic screen capable of detecting the misregulated activity of 13-lipoxygenase, which operates at the entry point of the jasmonate biosynthesis pathway. Leaf extracts from the Arabidopsis fou2 (fatty acid oxygenation upregulated 2) mutant displayed an increased capacity to catalyze the synthesis of lipoxygenase (LOX) metabolites. Quantitative oxylipin analysis identified less than twofold increased jasmonate levels in healthy fou2 leaves compared to wild-type; however, wounded fou2 leaves strongly increased jasmonate biogenesis compared to wounded wild-type. Furthermore, the plants displayed enhanced resistance to the fungus Botrytis cinerea. Higher than wild-type LOX activity and enhanced resistance in the fou2 mutant depend fully on a functional jasmonate response pathway. The fou2 mutant carries a missense mutation in the putative voltage sensor of the Two Pore Channel 1 gene (TPC1), which encodes a Ca(2+)-permeant non-selective cation channel. Patch-clamp analysis of fou2 vacuolar membranes showed faster time-dependent conductivity and activation of the mutated channel at lower membrane potentials than wild-type. The results indicate that cation fluxes exert strong control over the positive feedback loop whereby JA stimulates its own synthesis.

Influence of HLA-C expression level on HIV control.

A variant upstream of human leukocyte antigen C (HLA-C) shows the most significant genome-wide effect on HIV control in European Americans and is also associated with the level of HLA-C expression. We characterized the differential cell surface expression levels of all common HLA-C allotypes and tested directly for effects of HLA-C expression on outcomes of HIV infection in 5243 individuals. Increasing HLA-C expression was associated with protection against multiple outcomes independently of individual HLA allelic effects in both African and European Americans, regardless of their distinct HLA-C frequencies and linkage relationships with HLA-B and HLA-A. Higher HLA-C expression was correlated with increased likelihood of cytotoxic T lymphocyte responses and frequency of viral escape mutation. In contrast, high HLA-C expression had a deleterious effect in Crohn's disease, suggesting a broader influence of HLA expression levels in human disease.

Chromosome 7 gain and DNA hypermethylation at the HOXA10 locus are associated with expression of a stem cell related HOX-signature in glioblastoma.

BACKGROUND: HOX genes are a family of developmental genes that are expressed neither in the developing forebrain nor in the normal brain. Aberrant expression of a HOX-gene dominated stem-cell signature in glioblastoma has been linked with increased resistance to chemo-radiotherapy and sustained proliferation of glioma initiating cells. Here we describe the epigenetic and genetic alterations and their interactions associated with the expression of this signature in glioblastoma. RESULTS: We observe prominent hypermethylation of the HOXA locus 7p15.2 in glioblastoma in contrast to non-tumoral brain. Hypermethylation is associated with a gain of chromosome 7, a hallmark of glioblastoma, and may compensate for tumor-driven enhanced gene dosage as a rescue mechanism by preventing undue gene expression. We identify the CpG island of the HOXA10 alternative promoter that appears to escape hypermethylation in the HOX-high glioblastoma. An additive effect of gene copy gain at 7p15.2 and DNA methylation at key regulatory CpGs in HOXA10 is significantly associated with HOX-signature expression. Additionally, we show concordance between methylation status and presence of active or inactive chromatin marks in glioblastoma-derived spheres that are HOX-high or HOX-low, respectively. CONCLUSIONS: Based on these findings, we propose co-evolution and interaction between gene copy gain, associated with a gain of chromosome 7, and additional epigenetic alterations as key mechanisms triggering a coordinated, but inappropriate, HOX transcriptional program in glioblastoma.

Ultra-high-resolution 3D imaging of atherosclerosis in mice with synchrotron differential phase contrast: a proof of concept study.

The goal of this study was to investigate the performance of 3D synchrotron differential phase contrast (DPC) imaging for the visualization of both macroscopic and microscopic aspects of atherosclerosis in the mouse vasculature ex vivo. The hearts and aortas of 2 atherosclerotic and 2 wild-type control mice were scanned with DPC imaging with an isotropic resolution of 15 μm. The coronary artery vessel walls were segmented in the DPC datasets to assess their thickness, and histological staining was performed at the level of atherosclerotic plaques. The DPC imaging allowed for the visualization of complex structures such as the coronary arteries and their branches, the thin fibrous cap of atherosclerotic plaques as well as the chordae tendineae. The coronary vessel wall thickness ranged from 37.4 ± 5.6 μm in proximal coronary arteries to 13.6 ± 3.3 μm in distal branches. No consistent differences in coronary vessel wall thickness were detected between the wild-type and atherosclerotic hearts in this proof-of-concept study, although the standard deviation in the atherosclerotic mice was higher in most segments, consistent with the observation of occasional focal vessel wall thickening. Overall, DPC imaging of the cardiovascular system of the mice allowed for a simultaneous detailed 3D morphological assessment of both large structures and microscopic details.

Management Control for Corporate Sustainability Execution: The Role of Employee Compensation

The research described in this thesis examines the characteristics, the benefits and the challenges associated with the implementation of management accounting systems in the field of Corporate Social Responsibility (CSR). Applied to the CSR context, management accounting relates to the identification, elaboration and communication of information about an organization's interactions with the society and the environment. Based on this information, firms are able to make decisions to achieve social and environmental objectives and provide evidence justifying the benefits and the costs of such actions. The study begins by focusing on green management and exploring the characteristics of Environmental Management Accounting (EMA) systems within firms. The first chapter informs the reader about the growing body of EMA research and reveals unexplored relevant aspects that need to be further investigated. The work also emphasizes the importance of developing new theoretical hypotheses and appropriate research designs to empirically tackle new aspects of EMA and gain understanding on the use of these practices. Subsequently, given the acknowledged importance of control systems in influencing the behaviour of individuals within organizations, the remaining two chapters of the dissertation focus on the functioning of CSR-linked incentives assigned to employees in the form of compensation plans. The second chapter examines the determinants influencing corporate provision of incentives for the attainment of environmental targets. Empirical analysis of a sample of international firms reveals that companies are likely to use green incentives as mechanisms to increase the efficacy in contracting with their employees as well as to respond to social influences. Finally, the third chapter investigates the effectiveness of contracting associated with the use of CSR-linked executive compensation. Empirical analysis of a sample of US-based companies shows that corporate choice to tie senior executives' pay to CSR targets promotes the firm's CSR performance. Cette thèse examine les caractéristiques, avantages et défis associés à l'utilisation des systèmes de contrôle de gestion dans le domaine de la Responsabilité Sociale des Entreprises (RSE). Dans le contexte de la RSE, les activités du contrôle de gestion impliquent l'identification, l'élaboration et la communication d'informations qui concernent les interactions des organisations avec la société et l'environnement. Avec ces informations les entreprises sont en mesure de prendre des décisions visant à atteindre les objectifs sociaux et environnementaux de l'organisation et de documenter les bénéfices et coûts de ces actions. Dès le début, la thèse se concentre sur les caractéristiques des systèmes de contrôle de gestion environnementale au sein des entreprises. Le premier chapitre passe en revue la littérature existante et révèle des aspects inexplorés. Pour ce faire, le travail suggère le développement de nouvelles théories ainsi que l'utilisation de méthodes appropriées. Ces dernières doivent permettre d'aborder empiriquement de nouveaux aspects des systèmes de contrôle environnemental et faciliter la compréhension sur l'utilisation de ces pratiques. Considérant l'importance des systèmes de contrôle pour influencer le comportement des individus au sein des organisations, la suite du travail se concentre sur le fonctionnement des contrats de rémunération des employées liées aux résultats de la RSE. Plus particulièrement, le deuxième chapitre examine les facteurs qui influencent la décision des entreprises d'assigner des objectifs environnementaux aux employées. L'analyse empirique d'un échantillon d'entreprises internationales montre que les entreprises sont susceptibles d'utiliser des mécanismes incitatifs écologiques pour augmenter l'efficacité des contrats ainsi que pour répondre aux influences sociales. Finalement, le troisième chapitre analyse l'efficacité des contrats de rémunération des dirigeants liés aux résultats de la RSE. L'analyse empirique d'un échantillon de sociétés américaines indique que le choix de l'entreprise de lier la rémunération des dirigeants à des objectifs de la RSE favorise la performance RSE de l'organisation.

Regulatable and modulable background expression control in prokaryotic synthetic circuits by auxiliary repressor binding sites.

Expression control in synthetic genetic circuitry, for example, for construction of sensitive biosensors, is hampered by the lack of DNA parts that maintain ultralow background yet achieve high output upon signal integration by the cells. Here, we demonstrate how placement of auxiliary transcription factor binding sites within a regulatable promoter context can yield an important gain in signal-to-noise output ratios from prokaryotic biosensor circuits. As a proof of principle, we use the arsenite-responsive ArsR repressor protein from Escherichia coli and its cognate operator. Additional ArsR operators placed downstream of its target promoter can act as a transcription roadblock in a distance-dependent manner and reduce background expression of downstream-placed reporter genes. We show that the transcription roadblock functions both in cognate and heterologous promoter contexts. Secondary ArsR operators placed upstream of their promoter can also improve signal-to-noise output while maintaining effector dependency. Importantly, background control can be released through the addition of micromolar concentrations of arsenite. The ArsR-operator system thus provides a flexible system for additional gene expression control, which, given the extreme sensitivity to micrograms per liter effector concentrations, could be applicable in more general contexts.