The Nuclear Receptor LXR Limits Bacterial Infection of Host Macrophages through a Mechanism that Impacts Cellular NAD Metabolism

Macrophages exert potent effector functions against invading microorganisms but constitute, paradoxically, a preferential niche for many bacterial strains to replicate. Using a model of infection by Salmonella Typhimurium, we have identified a molecular mechanism regulated by the nuclear receptor LXR that limits infection of host macrophages through transcriptional activation of the multifunctional enzyme CD38. LXR agonists reduced the intracellular levels of NAD+ in a CD38-dependent manner, counteracting pathogen-induced changes in macrophage morphology and the distribution of the F-actin cytoskeleton and reducing the capability of non-opsonized Salmonella to infect macrophages. Remarkably, pharmacological treatment with an LXR agonist ameliorated clinical signs associated with Salmonella infection in vivo, and these effects were dependent on CD38 expression in bone-marrow-derived cells. Altogether, this work reveals an unappreciated role for CD38 in bacterial-host cell interaction that can be pharmacologically exploited by activation of the LXR pathway

La formación técnico profesional en el nivel superior no universitario de Argentina

El presente trabajo pretende problematizar la Formación Técnico Profesional en el Nivel Superior No Universitario en Argentina, habida cuenta de que la misma se constituye en el objeto de conocimiento del proceso de investigación que está desarrollando un equipo docente de la Facultad de Educación de la Universidad Católica de Córdoba de nuestro país, dirigido por el Dr. Horacio A. Ferreyra.Luego de una breve caracterización de las principales políticas públicas para la Educación Superior No Universitaria en Argentina en las últimas dos décadas (1990-2009), se presenta un marco teórico y conceptual producto de un relevamiento del estado del arte en el tema para abordar el estudio y análisis de este subsistema de la Educación Superior Argentina.Finalmente, este trabajo propone alternativas de mejoramiento de la calidad a modo de anticipaciones de sentido y posibles líneas de investigación a futuro. La convicción que moviliza el Proyecto y la Ponencia es la necesidad e importancia de construir aportes y propuestas para reorientar la transformación del subsistema ligado a las políticas de desarrollo socio-económico de la región y del país

Educación no formal y desarrollo regional en la provincia de Córdoba. Demandas, necesidades y ofertas de formación para el trabajo 2006 - 2007

Actualmente, la formación profesional enfrenta el desafío de adecuar su enfoque y sus prácticas para poder operar como un verdadero “nexo” entre las personas y el trabajo. El sistema de educación no formal de la provincia de Córdoba, debe asumir este desafío. El objetivo general de este trabajo fue conocer las demandas de formación profesional que surgen de la realidad socio-productiva de las diferentes regiones de la provincia de Córdoba a los efectos de contribuir con el rediseño de las ofertas educativas no formales de gestión estatal.Se realizó un estudio de tipo exploratorio-descriptivo de corte transversal, que partió del análisis de la oferta formativa que brindan los Centros de Desarrollo Regional (CEDER)2 en la Provincia de Córdoba. Se realizó una investigación bibliográfica acompañada de un trabajo de campo focalizado en los CEDER.Se centró en el análisis de la situación (Institucional y curricular) de los 31 CEDER (2006) y en el relevamiento de las ofertas y requerimientos de formación a nivel regional.Se elaboró y aplicó un cuestionario autoadministrado a todas las Instituciones, se realizaron entrevistas y encuestas individuales y grupales a informantes claves, a empresarios del sector primario, secundario y terciario de la economía provincial, a instituciones educativas, municipios y representantes de ONG.El informe se organizó en cuatro capítulos, una conclusión y un anexo. Resultados: se profundizó el conocimiento sobre la oferta de formación no formal existente en la provincia de Córdoba lo que posibilitó acercar propuestas tendientes a rediseñar la misma y contribuir a potenciar el desarrollo social y productivo regional

Exclusion of NFAT5 from Mitotic Chromatin Resets Its Nucleo-Cytoplasmic Distribution in Interphase

The transcription factor NFAT5 is a major inducer of osmoprotective genes and is required to maintain the proliferative capacity of cells exposed to hypertonic stress. In response to hypertonicity, NFAT5 translocates to the nucleus, binds to regulatory regions of osmoprotective genes and activates their transcription. Besides stimulus-specific regulatory mechanisms, the activity of transcription factors in cycling cells is also regulated by the passage through mitosis, when most transcriptional processes are downregulated. It was not known whether mitosis could be a point of control for NFAT5.Using confocal microscopy we observed that NFAT5 was excluded from chromatin during mitosis in both isotonic and hypertonic conditions. Analysis of NFAT5 deletions showed that exclusion was mediated by the carboxy-terminal domain (CTD). NFAT5 mutants lacking this domain showed constitutive binding to mitotic chromatin independent of tonicity, which caused them to localize in the nucleus and remain bound to chromatin in the subsequent interphase without hypertonic stimulation. We analyzed the contribution of the CTD, DNA binding, and nuclear import and export signals to the subcellular localization of this factor. Our results indicated that cytoplasmic localization of NFAT5 in isotonic conditions required both the exclusion from mitotic DNA and active nuclear export in interphase. Finally, we identified several regions within the CTD of NFAT5, some of them overlapping with transactivation domains, which were separately capable of causing its exclusion from mitotic chromatin.Our results reveal a multipart mechanism regulating the subcellular localization of NFAT5. The transactivating module of NFAT5 switches its function from an stimulus-specific activator of transcription in interphase to an stimulus-independent repressor of binding to DNA in mitosis. This mechanism, together with export signals acting in interphase, resets the cytoplasmic localization of NFAT5 and prevents its nuclear accumulation and association with DNA in the absence of hypertonic stress

The predictive value of p53, p53R2, and p21 for the effect of chemoradiation therapy on oesophageal squamous cell carcinoma

The p53 family regulates cell-cycle arrest, triggers apoptosis or is involved in repair of DNA damage. In the present study, we analysed the expression of some p53 family proteins and their responses to chemoradiation therapy (CRT) in cases of oesophageal squamous cell carcinoma (ESCC). We immunohistochemically investigated the relationship between p53, p53R2, and p21 expression in biopsy specimens of untreated primary tumours and their clinical and histological responses to CRT in 62 patients with ESCC. Chemoradiation therapy consisted of 5-fluorouracil plus cisplatin and 40 Gy of radiation. The rates of clinical and histological responses (complete or partial) to CRT were 71.0% (clinical) and 52.8% (histological). The rate of positive expression was 43.5% for p53, 37.1% for p53R2, and 54.8% for p21 expression. Statistically significant correlations were found between p53 or p53R2 expression and favourable response to CRT (P=0.0001 or 0.041 clinical, P=0.016 or 0.0018 histological, respectively). Furthermore, in p53-negative tumours, CRT was more effective in tumours with p53R2 negative expression than those with p53R2 positive expression (P=0.0014). We demonstrated that the negative expression of p53 and p53R2 expression was closely related to the effect of CRT and should predict the CRT outcome in patients with ESCC

Proteolytic cleavage of p53 mutants in response to mismatched DNA

Interaction of p53 with mismatched DNA induces proteolytic cleavage with release of a 35-kDa protein fragment from the p53–DNA complexes. The 35-kDa cleavage product is activated for specific biochemical function(s) and may play a role in the cellular response to DNA damage (Molinari et al (1996) Oncogene13: 2077–2086; Okorokov et al (1997) EMBO J16: 6008–6017). In the present study we have asked if mutants of p53 retain the ability to undergo similar proteolytic cleavage, and compared sequence-specific ‘DNA contact’ with ‘structural’ mutants commonly found in human cancer. In addition, a series of phosphorylation site mutants were generated to investigate the possible effects of phosphorylation/dephosphorylation on the proteolytic cleavage of p53. All mutants tested bound to a mismatched DNA target in vitro. Moreover, studies in vitro and in vivo indicate that p53 mutants with intact conformational structure (as determined by immunoreactivity with PAb246 and PAb1620) retain the ability to undergo proteolytic cleavage similar, if not identical, to the wild-type p53 protein. Our results suggest that the capacity for p53 to bind mismatched DNA is independent of structural conformation of the central core domain. Proteolytic cleavage, however, is crucially dependent upon a wild-type conformation of the protein. © 1999 Cancer Research Campaig

Prediction of cis-regulatory elements controlling genes differentially expressed by retinal and choroidal vascular endothelial cells

Cultured endothelial cells of the human retina and choroid demonstrate distinct patterns of gene expression. We hypothesized that differential gene expression reflected differences in the interactions of transcription factors and respective cis-regulatory motifs(s) in these two endothelial cell subpopulations, recognizing that motifs often exist as modules. We tested this hypothesis in silico by using TRANSFAC Professional and CisModule to identify cis-regulatory motifs and modules in genes that were differentially expressed by human retinal versus choroidal endothelial cells, as identified by analysis of a microarray data set. Motifs corresponding to eight transcription factors were significantly (p < 0.05) differentially abundant in genes that were relatively highly expressed in retinal (i.e., glucocorticoid receptor, high mobility group AT-hook 1, heat shock transcription factor 1, p53, vitamin D receptor) or choroidal (i.e., transcription factor E2F, Yin Yang 1, zinc finger 5) endothelial cells. Predicted cis-regulatory modules were quite different for these two groups of genes. Our findings raise the possibility of exploiting specific cis-regulatory motifs to target therapy at the ocular endothelial cells subtypes responsible for neovascular age-related macular degeneration or proliferative diabetic retinopathy

Antimetastatic gene expression profiles mediated by retinoic acid receptor beta 2 in MDA-MB-435 breast cancer cells

BACKGROUND: The retinoic acid receptor beta 2 (RARβ2) gene modulates proliferation and survival of cultured human breast cancer cells. Previously we showed that ectopic expression of RARβ2 in a mouse xenograft model prevented metastasis, even in the absence of the ligand, all-trans retinoic acid. We investigated both cultured cells and xenograft tumors in order to delineate the gene expression profiles responsible for an antimetastatic phenotype. METHODS: RNA from MDA-MB-435 human breast cancer cells transduced with RARβ2 or empty retroviral vector (LXSN) was analyzed using Agilent Human 1A Oligo microarrays. The one hundred probes with the greatest differential intensity (p < 0.004, jointly) were determined by selecting the top median log ratios from eight-paired microarrays. Validation of differences in expression was done using Northern blot analysis and quantitative RT-PCR (qRT-PCR). We determined expression of selected genes in xenograft tumors. RESULTS: RARβ2 cells exhibit gene profiles with overrepresentation of genes from Xq28 (p = 2 × 10(-8)), a cytogenetic region that contains a large portion of the cancer/testis antigen gene family. Other functions or factors impacted by the presence of exogenous RARβ2 include mediators of the immune response and transcriptional regulatory mechanisms. Thirteen of fifteen (87%) of the genes evaluated in xenograft tumors were consistent with differences we found in the cell cultures (p = 0.007). CONCLUSION: Antimetastatic RARβ2 signalling, direct or indirect, results in an elevation of expression for genes such as tumor-cell antigens (CTAG1 and CTAG2), those involved in innate immune response (e.g., RIG-I/DDX58), and tumor suppressor functions (e.g., TYRP1). Genes whose expression is diminished by RARβ2 signalling include cell adhesion functions (e.g, CD164) nutritional or metabolic processes (e.g., FABP6), and the transcription factor, JUN

Transcriptional repression of the human collagenase-1 (MMP-1) gene in MDA231 breast cancer cells by all-trans-retinoic acid requires distal regions of the promoter

In the present study, we investigated the mechanisms controlling constitutive transcription of collagenase-1 and its repression by all-trans-retinoic acid (RA) in the highly invasive metastatic and oestrogen-receptor-negative breast cancer cell line MDA231. A combination of in vivo and in vitro experiments that include DNAase I hypersensitivity assays, transient transfection of collagenase-1 promoter constructs, and electrophoretic mobility shift assays implicate several PEA3 sites, binding sites for Ets-related transcription factors, in the constitutive expression of the human collagenase-1 promoter. Transient transfection of promoter constructs linked to the luciferase reporter, along with gel retardation assays, revealed that repression of collagenase-1 transcription by RA is not dependent on the proximal AP-1 site, but, rather, requires sequences located in distal regions of the promoter. Transcriptional analyses and electrophoretic mobility shift assays suggest that the PEA3 site located at –3108 bp facilitates, at least in part, the transcriptional repression of the human collagenase-1 gene in MDA231 cells. We conclude that collagenase-1 repression in MDA231 cells occurs by a novel regulatory pathway that does not depend on the proximal AP-1 site at –73 bp, but does depend on distal regions in the collagenase-1 promoter. © 1999 Cancer Research Campaig

Computational Identification of Transcriptional Regulators in Human Endotoxemia

One of the great challenges in the post-genomic era is to decipher the underlying principles governing the dynamics of biological responses. As modulating gene expression levels is among the key regulatory responses of an organism to changes in its environment, identifying biologically relevant transcriptional regulators and their putative regulatory interactions with target genes is an essential step towards studying the complex dynamics of transcriptional regulation. We present an analysis that integrates various computational and biological aspects to explore the transcriptional regulation of systemic inflammatory responses through a human endotoxemia model. Given a high-dimensional transcriptional profiling dataset from human blood leukocytes, an elementary set of temporal dynamic responses which capture the essence of a pro-inflammatory phase, a counter-regulatory response and a dysregulation in leukocyte bioenergetics has been extracted. Upon identification of these expression patterns, fourteen inflammation-specific gene batteries that represent groups of hypothetically ‘coregulated’ genes are proposed. Subsequently, statistically significant cis-regulatory modules (CRMs) are identified and decomposed into a list of critical transcription factors (34) that are validated largely on primary literature. Finally, our analysis further allows for the construction of a dynamic representation of the temporal transcriptional regulatory program across the host, deciphering possible combinatorial interactions among factors under which they might be active. Although much remains to be explored, this study has computationally identified key transcription factors and proposed a putative time-dependent transcriptional regulatory program associated with critical transcriptional inflammatory responses. These results provide a solid foundation for future investigations to elucidate the underlying transcriptional regulatory mechanisms under the host inflammatory response. Also, the assumption that coexpressed genes that are functionally relevant are more likely to share some common transcriptional regulatory mechanism seems to be promising, making the proposed framework become essential in unravelling context-specific transcriptional regulatory interactions underlying diverse mammalian biological processes