1. Investigación

Although atherosclerosis preferentially develops at arterial curvatures and bifurcations where disturbed flow (DF) activates endothelium, therapies targeting flow-dependent mechanosensing pathways in the vasculature are unavailable. Here, we provided experimental evidence demonstrating a previously unidentified causal role of DF-induced endothelial TXNDC5 (thioredoxin domain containing 5) in atherosclerosis. TXNDC5 was increased in human and mouse atherosclerotic lesions and induced in endothelium subjected to DF. Endothelium-specific Txndc5 deletion markedly reduced atherosclerosis in ApoE−/− mice. Mechanistically, DF-induced TXNDC5 increases proteasome-mediated degradation of heat shock factor 1, leading to reduced heat shock protein 90 and accelerated eNOS (endothelial nitric oxide synthase) protein degradation. Moreover, nanoparticles formulated to deliver Txndc5-targeting CRISPR-Cas9 plasmids driven by an endothelium-specific promoter (CDH5) significantly increase eNOS protein and reduce atherosclerosis in ApoE−/− mice. These results delineate a new molecular paradigm that DF-induced endothelial TXNDC5 promotes atherosclerosis and establish a proof of concept of targeting endothelial mechanosensitive pathways in vivo against atherosclerosis.

Phage-inducible chromosomal islands (PICIs) are a widespread family of highly mobile genetic elements that disseminate virulence and toxin genes among bacterial populations. Since their life cycle involves induction by helper phages, they are important players in phage evolution and ecology. PICIs can interfere with the lifecycle of their helper phages at different stages resulting frequently in reduced phage production after infection of a PICIcontaining strain. Since phage defense systems have been recently shown to be beneficial for the acquisition of exogenous DNA via horizontal gene transfer, we hypothesized that PICIs could provide a similar benefit to their hosts and tested the impact of PICIs in recipient strains on host cell viability, phage propagation and transfer of genetic material. Here we report an important role for PICIs in bacterial evolution by promoting the survival of phagemediated transductants of chromosomal or plasmid DNA. The presence of PICIs generates favorable conditions for population diversification and the inheritance of genetic material being transferred, such as antibiotic resistance and virulence genes. Our results show that by interfering with phage reproduction, PICIs can protect the bacterial population from phage attack, increasing the overall survival of the bacterial population as well as the transduced cells. Moreover, our results also demonstrate that PICIs reduce the frequency of lysogenization after temperate phage infection, creating a more genetically diverse bacterial population with increased bet-hedging opportunities to adapt to new niches. In summary, our results identify a new role for the PICIs and highlight them as important drivers of bacterial evolution.

Mobile genetic elements control their life cycles by the expression of amaster repressor, whose function must be disabled to allow the spread of these elements in nature. Here,we describe an unprecedented repression-derepression mechanism involved in the transfer of Staphylococcus aureus pathogenicity islands (SaPIs). Contrary to the classical phage and SaPI repressors, which are dimers, the SaPI1 repressor StlSaPI1 presents a unique tetrameric conformation never seen before. Importantly, not just one but two tetramers are required for SaPI1 repression, which increases the novelty of the system. To derepress SaPI1, the phage-encoded protein Sri binds to and induces a conformational change in the DNA binding domains of StlSaPI1, preventing the binding of the repressor to its cognate StlSaPI1 sites. Finally, our findings demonstrate that this system is not exclusive to SaPI1 but widespread in nature. Overall, our results characterize a novel repression-induction system involved in the transfer of MGE-encoded virulence factors in nature.

Diabetes and metabolic syndrome are associated with the typical American high glycemia diet and result in accumulation of high levels of advanced glycation end products (AGEs), particularly upon aging. AGEs form when sugars or their metabolites react with proteins. Associated with a myriad of age-related diseases, AGEs accumulate in many tissues and are cytotoxic. To date, efforts to limit glycation pharmacologically have failed in human trials. Thus, it is crucial to identify systems that remove AGEs, but such research is scanty. Here, we determined if and how AGEs might be cleared by autophagy. Our in vivo mouse and C. elegans models, in which we altered proteolysis or glycative burden, as well as experiments in five types of cells, revealed more than six criteria indicating that p62-dependent autophagy is a conserved pathway that plays a critical role in the removal of AGEs. Activation of autophagic removal of AGEs requires p62, and blocking this pathway results in accumulation of AGEs and compromised viability. Deficiency of p62 accelerates accumulation of AGEs in soluble and insoluble fractions. p62 itself is subject to glycative inactivation and accumulates as high mass species. Accumulation of p62 in retinal pigment epithelium is reversed by switching to a lower glycemia diet. Since diminution of glycative damage is associated with reduced risk for age-related diseases, including age-related macular degeneration, cardiovascular disease, diabetes, Alzheimer's, and Parkinson's, discovery of methods to limit AGEs or enhance p62-dependent autophagy offers novel potential therapeutic targets to treat AGEs-related pathologies.

Although acute promyelocytic leukemia (APL) is one of the most characterized forms of acute myeloid leukemia (AML), the molecular mechanisms involved in the development and progression of this disease are still a matter of study. APL is defined by the PML-RARA rearrangement as a consequence of the translocation t(15;17)(q24;q21). However, this abnormality alone is not able to trigger the whole leukemic phenotype and secondary cooperating events might contribute to APL pathogenesis. Additional somatic mutations are known to occur recurrently in several genes, such as FLT3, WT1, NRAS and KRAS, whereas mutations in other common AML genes are rarely detected, resulting in a di erent molecular profile compared to other AML subtypes. How this mutational spectrum, including point mutations in the PML-RARA fusion gene, could contribute to the 10%–15% of relapsed or resistant APL patients is still unknown. Moreover, due to the uncertain impact of additional mutations on prognosis, the identification of the APL-specific genetic lesion is still the only method recommended in the routine evaluation/screening at diagnosis and for minimal residual disease (MRD) assessment. However, the gene expression profile of genes, such as ID1, BAALC, ERG, and KMT2E, once combined with the molecular events, might improve future prognostic models, allowing us to predict clinical outcomes and to categorize APL patients in di erent risk subsets, as recently reported. In this review, we will focus on the molecular characterization of APL patients at diagnosis, relapse and resistance, in both children and adults. We will also describe di erent standardized molecular approaches to study MRD, including those recently developed. Finally, we will discuss how novel molecular findings can improve the management of this disease.

El cáncer de mama representa la principal causa de muerte por cáncer en las mujeres españolas y valencianas. Con la introducción de los programas de cribado se ha detectado un aumento en la incidencia de cáncer de mama en estadios iniciales y del carcinoma intraductal. El carcinoma in situ es, por definición, una proliferación celular limitada exclusivamente al sistema ductal mamario que carece de capacidad de invasión y ,por tanto, de producir metástasis a distancia. La tasa de afectación axilar es baja, oscilando entre el 0 y el 5%, según las series. La biopsia selectiva del ganglio centinela es una técnica estandarizada para la valoración de afectación ganglionar axilar en pacientes con cáncer de mama invasivo. Su papel en CDIS es controvertido por la baja probabilidad de metástasis. Existen determinadas características clínico-patológicas (tamaño tumoral, alto grado histológico, presencia de comedonecrosis, masa palpable al diagnóstico, pacientes candidatas a mastectomía…) asociadas en la literatura con la capacidad de invasión y de producir metástasis. Este subgrupo de pacientes podría beneficiarse de la realización de la biopsia selectiva del ganglio centinela. Los objetivos de este trabajo son:  Analizar los factores clínico-patológicos (tamaño tumoral, alto grado histológico, presencia de comedonecrosis, masa palpable al diagnóstico y pacientes candidatas a mastectomía) asociados con la existencia de afectación ganglionar axilar en una muestra poblacional.  Determinar los criterios establecidos para la realización de la biopsia selectiva del ganglio centinela en cada caso.  Valorar la aplicación de las recomendaciones establecidas por el Consenso del Grupo Español de Senología y Patología Mamaria para la realización de ganglio centinela en CDIS. La población a estudio han sido 117 mujeres con carcinoma in situ de mama confirmado histopatológicamente, intervenidas y tratadas en el Hospital General y en el Consorcio Hospitalario Provincial de Castellón entre Octubre de 2006 y Noviembre de 2013. Se han descartado 8 pacientes por diferentes motivos por lo que la muestra ha quedado reducida a 109 pacientes. Se elaboró una base de datos con el programa SPSS Statistics® versión 20 de IBM®. Se han recogido diferentes variables agrupadas en los siguientes apartados:  Variables relacionadas con la población a estudio.  Variables relacionadas con la forma de presentación y diagnóstico.  Variables relacionadas con las características histopatológicas del tumor.  Variables relacionadas con el tratamiento.  Variables relacionadas con el resultado de la BSGC. Además de la estadística descriptiva de las variables, se ha realizado comparación estadística. En las variables cualitativas se aplicó el ji-cuadrado con la corrección de Yates y la prueba exacta de Fisher. En las cuantitativas se ha utilizado el análisis de la varianza o la prueba no paramétrica de Kruskall-Wallis en caso de ausencia de normalidad. En la comparación de variables cuantitativas se ha utilizado la prueba T para muestras independientes, tras comprobación de la normalidad de la distribución mediante la prueba de Kolmogorov-Smirnov. En la estadística analítica se han estudiado las posibles asociaciones entre las variables establecidas por el Consenso Español de Senología y Patología Mamaria para la realización del ganglio centinela y el resultado obtenido en el mismo. Se han detectado algunas asociaciones estadísticamente significativas. Esto puede estar en concordancia con la tasa de realización del ganglio y el número de pacientes en las que se ha realizado.