Dystroglycan Depletion Impairs Actin-Dependent Functions of Differentiated Kasumi-1 Cells

Background Dystroglycan has recently been characterised in blood tissue cells, as part of the dystrophin glycoprotein complex involved in the differentiation process of neutrophils. Purpose In the present study we have investigated the role of dystroglycan in the human promyelocytic leukemic cell line Kasumi-1 differentiated to macrophage-like cells. Methods We characterised the pattern expression and subcellular distribution of dystroglycans in non-differentiated and differentiated Kasumi-1 cells. Results Our results demonstrated by WB and flow cytometer assays that during the differentiation process to macrophages, dystroglycans were down-regulated; these results were confirmed with qRT-PCR assays. Additionally, depletion of dystroglycan by RNAi resulted in altered morphology and reduced properties of differentiated Kasumi-1 cells, including morphology, migration and phagocytic activities although secretion of IL-1β and expression of markers of differentiation are not altered. Conclusion Our findings strongly implicate dystroglycan as a key membrane adhesion protein involved in actin-based structures during the differentiation process in Kasumi-1 cells

A role for dystroglycan in the pathophysiology of acute leukemic cells.

AIMS: Previous reports have demonstrated that alterations or reduced expression of Dystroglycan (Dg) complex (αDg and βDg subunits) are related to progression and severity of neoplastic solid tissues. Therefore we determined the expression pattern and subcellular distribution of Dg complex in Acute Myeloid Leukemia (AML) primary blasts (M1, M2, and M3 phenotypes), as well as HL-60 and Kasumi-1 leukemia cell lines. Additionally, we evaluated the relative expression of the main enzymes controlling α-Dg glycosylation to ascertain the post-translational modifications in the leukemia cell phenotype. MAIN METHODS: Primary leukemia blasts and leukemia cell lines were processed by confocal analysis to determine the subcellular distribution of α-Dg, β-Dg, and phosphorylated β-Dg (Y892), to evaluate the expression pattern of the different Dg species we performed Western Blot (WB) assays, while the messenger RNA (mRNA) expression of enzymes involved in α-Dg glycosylation, such as POMGnT1, POMT1, POMT2, LARGE, FKTN, and FKRP, were evaluated by qualitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). Finally, in an attempt to ameliorate the leukemia cell phenotype, we transfected leukemia cells with a plasmid expressing the Dg complex. KEY FINDINGS: The Dg complex was altered in leukemia cells, including decreased mRNA, protein, and α-Dg glycosylated levels, mislocalization of β-Dg, and a diminution of mRNA expression of LARGE in patients leukemia blasts and in cell lines. Interestingly, the exogenous expression of Dg complex promoted filopodial formation, differentiation, and diminished proliferation, attenuating some HL-60 and Kasumi cells characteristics. SIGNIFICANCE: Dg complex integrity and balance are required for a proper hematopoietic cell function, in that its disruption might contribute to leukemia pathophysiology

The molecular basis and biologic significance of the β-dystroglycan-emerin interaction

β-dystroglycan (β-DG) assembles with lamins A/C and B1 and emerin at the nuclear envelope (NE) to maintain proper nuclear architecture and function. To provide insight into the nuclear function of β-DG, we characterized the interaction between β-DG and emerin at the molecular level. Emerin is a major NE protein that regulates multiple nuclear processes and whose deficiency results in Emery–Dreifuss muscular dystrophy (EDMD). Using truncated variants of β-DG and emerin, via a series of in vitro and in vivo binding experiments and a tailored computational analysis, we determined that the β-DG–emerin interaction is mediated at least in part by their respective transmembrane domains (TM). Using surface plasmon resonance assays we showed that emerin binds to β-DG with high affinity (KD in the nanomolar range). Remarkably, the analysis of cells in which DG was knocked out demonstrated that loss of β-DG resulted in a decreased emerin stability and impairment of emerin-mediated processes. β-DG and emerin are reciprocally required for their optimal targeting within the NE, as shown by immunofluorescence, western blotting and immunoprecipitation assays using emerin variants with mutations in the TM domain and B-lymphocytes of a patient with EDMD. In summary, we demonstrated that β-DG plays a role as an emerin interacting partner modulating its stability and function

The intracellular domain of β-dystroglycan mediates the nucleolar stress response by suppressing UBF transcriptional activity

β-dystroglycan (β-DG) is a key component of multiprotein complexes in the plasma membrane and nuclear envelope. In addition, β-DG undergoes two successive proteolytic cleavages that result in the liberation of its intracellular domain (ICD) into the cytosol and nucleus. However, stimuli-inducing ICD cleavage and the physiological relevance of this proteolytic fragment are largely unknown. In this study we show for the first time that β-DG ICD is targeted to the nucleolus where it interacts with the nuclear proteins B23 and UBF (central factor of Pol I-mediated rRNA gene transcription) and binds to rDNA promoter regions. Interestingly DG silencing results in reduced B23 and UBF levels and aberrant nucleolar morphology. Furthermore, β-DG ICD cleavage is induced by different nucleolar stressors, including oxidative stress, acidosis, and UV irradiation, which implies its participation in the response to nucleolar stress. Consistent with this idea, overexpression of β-DG elicited mislocalization and decreased levels of UBF and suppression of rRNA expression, which in turn provoked altered ribosome profiling and decreased cell growth. Collectively our data reveal that β-DG ICD acts as negative regulator of rDNA transcription by impeding the transcriptional activity of UBF, as a part of the protective mechanism activated in response to nucleolar stress

Oportunidad ecológica y radiación adaptativa en Salvia (subgen. calosphace): El rol de los polinizadores en la diversificación

La Oportunidad Ecológica (OE), definida como las circunstancias que promueven la diversificación ecológica de especies, puede originarse mediante diferentes mecanismos como la aparición de rasgos clave, colonización de áreas geográficas nuevas o aparición de nuevos recursos en un área determinada. Las Radiaciones Adaptativas (RA), generalmente promovidas por OE, constituyen uno de los procesos más importantes que integran ecología y evolución. En varios grupos de plantas sujetos a RA mediadas por polinizadores, la evolución hacia la polinización por aves (ornitofilia) constituye una de las transiciones más comunes, generalmente desde la polinización por abejas (melitofilia), y ha tenido grandes efectos en su evolución. En las especies neotropicales de Salvia (subgen. Calosphace, de origen mexicano), proponemos que la aparición de los picaflores durante la recolonización de América del Norte (AN) desde América del Sur (AS), generó la OE que promovió la radiación del grupo. Para probar esta hipótesis, utilizamos diferentes métodos filogenéticos comparativos para indagar y discutir sobre, a) la historia evolutiva de los síndromes de polinización, utilizando dos métodos de reconstrucción ancestral, b) los patrones macroevolutivos de diversificación morfológica y de especies (usando DTT y BAMM, respectivamente) y c) el papel de grandes eventos históricos/geológicos que habrían determinado la coexistencia de las especies de Calosphace y sus polinizadores. Ambas reconstrucciones ancestrales estimaron un origen melitófilo, al menos 6 transiciones independientes a la ornitofilia y numerosas reversiones. El primer origen de la ornitofilia en Calosphace, coincide temporalmente con la recolonización de AN por los picaflores sudamericanos, y además con el aumento en la tasa de especiación (BAMM). Además, el origen de los Andes centrales (hace ~10-5 Ma) parece haber modulado la distribución y diversificación de picaflores y de especies sudamericanas de Calosphace. Los análisis de diversificación morfológica (DTT) también muestran un aumento de disparidad coincidente con el primer origen de la ornitofilia (hace ~11 Ma). Adicionalmente, encontramos que los patrones de correlación de dos rasgos florales se conservan en clados con distintos síndromes, sin embargo la tasa de diversificación de uno de ellos (longitud operativa) es mayor en clados ornitófilos, sugiriendo un mecanismo de evolución a través de un eje alométrico. En este trabajo mostramos, desde diferentes enfoques, que el encuentro e interacción con picaflores constituyó la OE que derivó en la diversificación de Calosphace y que se ve reflejada en los patrones macroevolutivos de diversidad morfológica y de especies en este grupo megadiverso de plantas.Fil: Sazatornil, Federico David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Fornoni, Juan Enrique. Universidad Nacional Autonoma de Mexico. Instituto de Ecologia. Departamento de Ecologia Funcional; MéxicoFil: Fragoso Martínez, I.. Universidad Nacional Autónoma de México. Instituto de Biología; MéxicoFil: Pérez Ishiwara, J.R.. Universidad Nacional Autonoma de Mexico. Instituto de Ecologia. Departamento de Ecologia Funcional; MéxicoFil: Salazar, G.. Universidad Nacional Autónoma de México. Instituto de Biología; MéxicoFil: Benitez Vieyra, Santiago Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaIII Reunión Argentina de Biología EvolutivaBuenos AiresArgentinaSociedad Argentina de Biología Evolutiv

Excavacions arqueològiques al monestir de Sant Pere de Rodes: primers resultats

Sobre els primers resultats de les excavacions arqueològiques al monestir de Sant Pere de Rode

Calidad y cumplimiento de guías de práctica clínica de enfermedades crónicas no transmisibles en el primer nivel

Objetivo. Evaluar la calidad y cumplimiento de guías de práctica clínica (GPC) aplicables a las enfermedades crónicas no transmisibles (ECNT) en Centros de Salud (CS), y opinión del personal sobre las barreras, facilitadores y su utilización. Material y métodos. De 18 GPC valoradas con Appraisal of Guidelines Research and Evaluation II (AGREEII), se seleccionan tres para elaborar indicadores y evaluar cumplimiento usando Lot Quality Assurance Sampling (LQAS) estándar 75/95%, umbral 40/75%, respectivamente, α:0.05, β:0.10) en cinco CS. 70 profesionales fueron encuestados sobre conocimiento y utilización de GPC. Resultados. La calidad formal promedio de las GPC fue 57.2%; baja calificación en dominios:“Aplicabilidad” (<25%), “Participación de los implicados”(43.5%) y “Rigor en la elaboración” (55.0%). Su cumplimiento en CS oscila entre 39 y 53.4%. Los profesionales muestran conocimiento desigual de GPC; de 44 a 45% (según GPC)declaran que no se utilizan e identifican como principales barreras la ausencia de capacitación y su difícil accesibilidad y anejo. Conclusiones. La calidad e implantación de GPC evaluadas es deficiente, lo que constituye una oportunidad de mejora en los servicios de salud

Phylogeny of the Neotropical sages (Salvia subg. Calosphace; Lamiaceae) and insights into pollinator and area shifts

Salvia subg. Calosphace (Lamiaceae, Lamiales) is a highly diverse clade endemic to the New World. The phylogenetic relationships of Calosphace have been previously investigated using DNA sequences of nuclear ITS region and plastid psbA–trnH intergenic spacer, but the resulting trees lack resolution and support for many clades. The present paper reassesses the phylogenetic relationships of subgenus Calosphace, including a broader taxon sampling, with a special focus on representing previously unsampled sections, and using an additional plastid marker (trnL–trnF region). Our results show increased resolution and overall patterns of support, recovering ten main clades. Within core Calosphace, the most inclusive of these main clades, 17 new subclades were identified. Of the 42 sections for which more than one species was analysed, only 12 are monophyletic. Our biogeographical analysis identified at least twelve migrations to South America from Mexican and Central American lineages, in agreement with previous suggestions of multiple origins of South American Calosphace diversity. This analysis also confirmed a colonization of the Antilles by Andean lineages. The reconstruction of ancestral states of pollination syndromes showed multiple shifts to ornithophily from melittophily and one reversal to the latter.Fil: Fragoso-Martínez, Itzi. Universidad Nacional Autónoma de México; MéxicoFil: Martínez-Gordillo, Martha. Universidad Nacional Autónoma de México; MéxicoFil: Salazar, Gerardo A.. Universidad Nacional Autónoma de México; MéxicoFil: Sazatornil, Federico David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Jenks, Aaron A.. Berkeley University; Estados UnidosFil: García Peña, María del Rosario. Universidad Nacional Autónoma de México; MéxicoFil: Barrera-Aveleida, Giovanna. Universidad Nacional Autónoma de México; MéxicoFil: Benitez Vieyra, Santiago Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Magallón, Susana. Universidad Nacional Autónoma de México; MéxicoFil: Cornejo-Tenorio, Guadalupe. Universidad Nacional Autónoma de México; MéxicoFil: Granados Mendoza, Carolina. Universidad Nacional Autónoma de México; Méxic

Nuclear targeting of dystroglycan promotes the expression of androgen regulated transcription factors in prostate cancer

Dystroglycan is frequently lost in adenocarcinoma, but the mechanisms and consequences are poorly understood. We report an analysis of beta-dystroglycan in prostate cancer in human tissue samples and in LNCaP cells in vitro. There is progressive loss of beta-dystroglycan immunoreactivity from basal and lateral surfaces of prostate epithelia which correlates significantly with increasing Gleason grade. In about half of matched bone metastases there is significant dystroglycan re-expression. In tumour tissue and in LNCaP cells there is also a tyrosine phosphorylation-dependent translocation of beta-dystroglycan to the nucleus. Analysis of gene expression data by microarray, reveals that nuclear targeting of beta-dystroglycan in LNCaP cells alters the transcription of relatively few genes, the most unregulated being the transcription factor ETV1. These data suggest that proteolysis, tyrosine phosphorylation and translocation of dystroglycan to the nucleus resulting in altered gene transcription could be important mechanisms in the progression of prostate cancer