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1.
Nat Commun ; 13(1): 5383, 2022 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-36104323

RESUMEN

Adaptive immunity depends on cell surface presentation of antigenic peptides by major histocompatibility complex class I (MHC I) molecules and on stringent ER quality control in the secretory pathway. The chaperone tapasin in conjunction with the oxidoreductase ERp57 is crucial for MHC I assembly and for shaping the epitope repertoire for high immunogenicity. However, how the tapasin-ERp57 complex engages MHC I clients has not yet been determined at atomic detail. Here, we present the 2.7-Å crystal structure of a tapasin-ERp57 heterodimer in complex with peptide-receptive MHC I. Our study unveils molecular details of client recognition by the multichaperone complex and highlights elements indispensable for peptide proofreading. The structure of this transient ER quality control complex provides the mechanistic basis for the selector function of tapasin and showcases how the numerous MHC I allomorphs are chaperoned during peptide loading and editing.


Asunto(s)
Antígenos de Histocompatibilidad Clase I , Proteínas de Transporte de Membrana , Antígenos HLA , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Proteínas de Transporte de Membrana/metabolismo , Chaperonas Moleculares/metabolismo , Péptidos/química , Proteína Disulfuro Isomerasas/metabolismo
2.
Cell Death Differ ; 29(3): 492-503, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34535764

RESUMEN

Primary or acquired therapy resistance is a major obstacle to the effective treatment of cancer. Resistance to apoptosis has long been thought to contribute to therapy resistance. We show here that recombinant TRAIL and CDK9 inhibition cooperate in killing cells derived from a broad range of cancers, importantly without inducing detectable adverse events. Remarkably, the combination of TRAIL with CDK9 inhibition was also highly effective on cancers resistant to both, standard-of-care chemotherapy and various targeted therapeutic approaches. Dynamic BH3 profiling revealed that, mechanistically, combining TRAIL with CDK9 inhibition induced a drastic increase in the mitochondrial priming of cancer cells. Intriguingly, this increase occurred irrespective of whether the cancer cells were sensitive or resistant to chemo- or targeted therapy. We conclude that this pro-apoptotic combination therapy has the potential to serve as a highly effective new treatment option for a variety of different cancers. Notably, this includes cancers that are resistant to currently available treatment modalities.


Asunto(s)
Antineoplásicos , Neoplasias , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis , Línea Celular Tumoral , Mitocondrias , Neoplasias/tratamiento farmacológico , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología
3.
Mol Cell ; 77(5): 970-984.e7, 2020 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-31982308

RESUMEN

Cytosolic caspase-8 is a mediator of death receptor signaling. While caspase-8 expression is lost in some tumors, it is increased in others, indicating a conditional pro-survival function of caspase-8 in cancer. Here, we show that tumor cells employ DNA-damage-induced nuclear caspase-8 to override the p53-dependent G2/M cell-cycle checkpoint. Caspase-8 is upregulated and localized to the nucleus in multiple human cancers, correlating with treatment resistance and poor clinical outcome. Depletion of caspase-8 causes G2/M arrest, stabilization of p53, and induction of p53-dependent intrinsic apoptosis in tumor cells. In the nucleus, caspase-8 cleaves and inactivates the ubiquitin-specific peptidase 28 (USP28), preventing USP28 from de-ubiquitinating and stabilizing wild-type p53. This results in de facto p53 protein loss, switching cell fate from apoptosis toward mitosis. In summary, our work identifies a non-canonical role of caspase-8 exploited by cancer cells to override the p53-dependent G2/M cell-cycle checkpoint.


Asunto(s)
Caspasa 8/metabolismo , Núcleo Celular/enzimología , Proliferación Celular , Puntos de Control de la Fase G2 del Ciclo Celular , Neoplasias/enzimología , Proteína p53 Supresora de Tumor/metabolismo , Ubiquitina Tiolesterasa/metabolismo , Antineoplásicos/farmacología , Apoptosis , Caspasa 8/genética , Núcleo Celular/efectos de los fármacos , Núcleo Celular/genética , Núcleo Celular/patología , Proliferación Celular/efectos de los fármacos , Resistencia a Antineoplásicos , Femenino , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Regulación Enzimológica de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Células HCT116 , Células HeLa , Humanos , Células MCF-7 , Masculino , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Neoplasias/patología , Células PC-3 , Estabilidad Proteica , Transducción de Señal , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/genética , Ubiquitina Tiolesterasa/genética
4.
NPJ Syst Biol Appl ; 4: 39, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30416750

RESUMEN

Metastatic melanoma remains a life-threatening disease because most tumors develop resistance to targeted kinase inhibitors thereby regaining tumorigenic capacity. We show the 2nd generation hexavalent TRAIL receptor-targeted agonist IZI1551 to induce pronounced apoptotic cell death in mutBRAF melanoma cells. Aiming to identify molecular changes that may confer IZI1551 resistance we combined Dynamic Bayesian Network modelling with a sophisticated regularization strategy resulting in sparse and context-sensitive networks and show the performance of this strategy in the detection of cell line-specific deregulations of a signalling network. Comparing IZI1551-sensitive to IZI1551-resistant melanoma cells the model accurately and correctly predicted activation of NFκB in concert with upregulation of the anti-apoptotic protein XIAP as the key mediator of IZI1551 resistance. Thus, the incorporation of multiple regularization functions in logical network optimization may provide a promising avenue to assess the effects of drug combinations and to identify responders to selected combination therapies.

5.
J Vis Exp ; (135)2018 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-29863656

RESUMEN

Malignant transformation of melanocytes, the pigment cells of human skin, causes formation of melanoma, a highly aggressive cancer with increased metastatic potential. Recently, mono-chemotherapies continue to improve by melanoma specific combination therapies with targeted kinase inhibitors. Still, metastatic melanoma remains a life-threatening disease because tumors exhibit primary resistance or develop resistance to novel therapies, thereby regaining tumorigenic capacity. In order to improve the therapeutic success of malignant melanoma, the determination of molecular mechanisms conferring resistance against conventional treatment approaches is necessary; however, it requires innovative cellular in vitro models. Here, we introduce an in vitro three-dimensional (3D) organotypic melanoma spheroid model that can portray the in vivo architecture of malignant melanoma and may warrant new insights into intra-tumoral as well as tumor-host interactions. The model incorporates defined numbers of mature and differentiated melanoma spheroids in a 3D human full skin reconstruction model consisting of primary skin cells. The cellular composition and differentiation status of the embedded melanoma spheroids is similar to the one of cutaneous melanoma metastasis in vivo. Using this organotypic melanoma spheroid model as a drug screening platform may support the identification of responders to selected combination therapies, while sparing the unnecessary treatment burden for non-responders, thereby increasing the benefit of therapeutic interventions.


Asunto(s)
Transformación Celular Neoplásica/genética , Melanoma/diagnóstico , Neoplasias Cutáneas/diagnóstico , Esferoides Celulares/patología , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Humanos , Melanoma/patología , Neoplasias Cutáneas/patología , Melanoma Cutáneo Maligno
6.
Sci Rep ; 8(1): 7808, 2018 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-29773864

RESUMEN

Single-chain formats of TNF-related apoptosis inducing ligand (scTRAIL) can serve as effector components of tumour-associated antigen-targeted as well as non-targeted fusion proteins, being characterized by high tumour cell-specific induction of apoptosis through death receptor activation. We studied the suitability of immunoglobulin G as a scaffold for oligovalent and bispecific TRAIL fusion proteins. Thus, we developed novel targeted hexa- and dodecavalent IgG-scTRAIL molecules by fusing scTRAIL to the C-terminus of either light (LC-scTRAIL) or heavy immunoglobulin chain (HC-scTRAIL), or to both ends (LC/HC-scTRAIL) of the anti-EGFR IgG antibody hu225. The binding specificity to EGFR and death receptors was retained in all IgG-scTRAIL formats and translated into high antigen-specific bioactivity on EGFR-positive Colo205, HCT116 and WM1366 tumour cell lines, with or without sensitization to apoptosis by bortezomib. In vivo, therapeutic potential was assessed for one of the targeted variants, HC-scTRAIL, compared to the non-targeted Fc-scTRAIL. Both molecules showed a significant reduction of tumour volume and synergism with a Smac mimetic in a Colo205 xenograft tumour model. The IgG-scTRAIL format allows directing a defined, highly bioactive form of TRAIL to a wide variety of tumour antigens, enabling customized solutions for a patient-specific targeted cancer therapy with a reduced risk of side effects.


Asunto(s)
Inmunoglobulina G/farmacología , Proteínas Recombinantes de Fusión/farmacología , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Anticuerpos Monoclonales Humanizados/farmacología , Antineoplásicos/farmacología , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Receptores ErbB/inmunología , Humanos , Inmunoglobulina G/química , Ligando Inductor de Apoptosis Relacionado con TNF/química
7.
Nat Commun ; 9(1): 341, 2018 01 23.
Artículo en Inglés | MEDLINE | ID: mdl-29362459

RESUMEN

G protein-independent, arrestin-dependent signaling is a paradigm that broadens the signaling scope of G protein-coupled receptors (GPCRs) beyond G proteins for numerous biological processes. However, arrestin signaling in the collective absence of functional G proteins has never been demonstrated. Here we achieve a state of "zero functional G" at the cellular level using HEK293 cells depleted by CRISPR/Cas9 technology of the Gs/q/12 families of Gα proteins, along with pertussis toxin-mediated inactivation of Gi/o. Together with HEK293 cells lacking ß-arrestins ("zero arrestin"), we systematically dissect G protein- from arrestin-driven signaling outcomes for a broad set of GPCRs. We use biochemical, biophysical, label-free whole-cell biosensing and ERK phosphorylation to identify four salient features for all receptors at "zero functional G": arrestin recruitment and internalization, but-unexpectedly-complete failure to activate ERK and whole-cell responses. These findings change our understanding of how GPCRs function and in particular of how they activate ERK1/2.


Asunto(s)
Proteínas de Unión al GTP/genética , Sistema de Señalización de MAP Quinasas , Receptores Acoplados a Proteínas G/metabolismo , beta-Arrestina 1/metabolismo , Arrestina beta 2/metabolismo , Sistemas CRISPR-Cas , Subunidades alfa de la Proteína de Unión al GTP/genética , Subunidades alfa de la Proteína de Unión al GTP G12-G13/genética , Subunidades alfa de la Proteína de Unión al GTP Gs/genética , Proteínas de Unión al GTP/metabolismo , Técnicas de Inactivación de Genes , Células HEK293 , Humanos , Fosforilación , Transducción de Señal , beta-Arrestinas/metabolismo
8.
Mol Cancer Ther ; 16(12): 2792-2802, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28904131

RESUMEN

The TNF-related apoptosis-inducing ligand (TRAIL) has been considered as a promising molecule for cancer treatment. However, clinical studies with soluble TRAIL failed to show therapeutic activity, which resulted in subsequent development of more potent TRAIL-based therapeutics. In this study, we applied defined oligomerization and tumor targeting as strategies to further improve the activity of a single-chain version of TRAIL (scTRAIL). We compared three different formats of EGF receptor (EGFR)-targeting dimeric scTRAIL fusion proteins [Diabody (Db)-scTRAIL, scFv-IgE heavy chain domain 2 (EHD2)-scTRAIL, scFv-Fc-scTRAIL] as well as two nontargeted dimeric scTRAIL molecules (EHD2-scTRAIL, Fc-scTRAIL) to reveal the influence of targeting and protein format on antitumor activity. All EGFR-targeted dimeric scTRAIL molecules showed similar binding properties and comparable cell death induction in vitro, exceeding the activity of the respective nontargeted dimeric format and monomeric scTRAIL. Superior properties were observed for the Fc fusion proteins with respect to production and in vivo half-life. In vivo studies using a Colo205 xenograft model revealed potent antitumor activity of all EGFR-targeting formats and Fc-scTRAIL and furthermore highlighted the higher efficacy of fusion proteins comprising an Fc part. Despite enhanced in vitro cell death induction of targeted scTRAIL molecules, however, comparable antitumor activities were found for the EGFR-targeting scFv-Fc-scTRAIL and the nontargeting Fc-scTRAIL in vivoMol Cancer Ther; 16(12); 2792-802. ©2017 AACR.


Asunto(s)
Proteínas Recombinantes de Fusión/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Animales , Apoptosis , Línea Celular Tumoral , Femenino , Humanos , Ratones , Ensayos Antitumor por Modelo de Xenoinjerto
9.
Beilstein J Nanotechnol ; 6: 300-12, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25821668

RESUMEN

In the research field of nanoparticles, many studies demonstrated a high impact of the shape, size and surface charge, which is determined by the functionalization, of nanoparticles on cell viability and internalization into cells. This work focused on the comparison of three different nanoparticle types to give a better insight into general rules determining the biocompatibility of gold, Janus and semiconductor (quantum dot) nanoparticles. Endothelial cells were subject of this study, since blood is the first barrier after intravenous nanoparticle application. In particular, stronger effects on the viability of endothelial cells were found for nanoparticles with an elongated shape in comparison to spherical ones. Furthermore, a positively charged nanoparticle surface (NH2, CyA) leads to the strongest reduction in cell viability, whereas neutral and negatively charged nanoparticles are highly biocompatible to endothelial cells. These findings are attributed to a rapid internalization of the NH2-functionalized nanoparticles in combination with the damage of intracellular membranes. Interestingly, the endocytotic pathway seems to be a size-dependent process whereas nanoparticles with a size of 20 nm are internalized by caveolae-mediated endocytosis and nanoparticles with a size of 40 nm are taken up by clathrin-mediated internalization and macropinocytosis. Our results can be summarized to formulate five general rules, which are further specified in the text and which determine the biocompatibility of nanoparticles on endothelial cells. Our findings will help to design new nanoparticles with optimized properties concerning biocompatibility and uptake behavior with respect to the respective intended application.

10.
J Invest Dermatol ; 135(3): 851-860, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25380350

RESUMEN

In response to genotoxic stress, including UVB radiation, transcription factors NF-κB and p53 inevitably influence the cellular fate. Loss of p53 function has been attributed to malignant transformation and interferes with therapeutic interventions, whereas "gain of function" mutants even enhance tumor promotion. Constitutive NF-κB activation is linked to tumor maintenance and resistance against chemotherapy. The cross talk between p53 and NF-κB, however, is still under debate. Using the non-transformed keratinocyte cell line HaCaT, we shed light on the interplay between p53 and NF-κB by providing clear evidence that chronically activated NF-κB together with designated "gain of function" mutp53 promotes apoptosis via cooperative tumor necrosis factor (TNF) production in response to UVB+IL-1. Performing chromatin immunoprecipitation analysis we demonstrate that both transcription factors bind to the TNF promoter, whereas UVB-induced inhibition of Ser-Thr-phosphatase protein phosphatase 2A facilitates prolonged phosphorylation of NF-κB and the transcriptional cofactor cAMP response element-binding protein, both being required for extended TNF transcription. Thus, two major anti-apoptotic factors, NF-κB and mutp53, in concert may generate pro-apoptotic responses. As human skin is constantly exposed to UVB, causing IL-1 production as well, we hypothesize that the remarkable amount of hotspot p53 mutations within the epidermis (4%) may serve a protective function to eliminate precancerous cells at an early stage.


Asunto(s)
Apoptosis/fisiología , Interleucina-1/farmacología , Queratinocitos/efectos de los fármacos , Queratinocitos/efectos de la radiación , FN-kappa B/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta/efectos adversos , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Línea Celular , Inmunoprecipitación de Cromatina , Ensayo de Unidades Formadoras de Colonias , Daño del ADN/efectos de los fármacos , Daño del ADN/efectos de la radiación , Humanos , Queratinocitos/metabolismo , Fosforilación , Transcripción Genética , Factor de Necrosis Tumoral alfa/genética
11.
BMC Genomics ; 15: 537, 2014 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-24973960

RESUMEN

BACKGROUND: Segmental duplications (SDs) are not evenly distributed along chromosomes. The reasons for this biased susceptibility to SD insertion are poorly understood. Accumulation of SDs is associated with increased genomic instability, which can lead to structural variants and genomic disorders such as the Williams-Beuren syndrome. Despite these adverse effects, SDs have become fixed in the human genome. Focusing on chromosome 7, which is particularly rich in interstitial SDs, we have investigated the distribution of SDs in the context of evolution and the three dimensional organisation of the chromosome in order to gain insights into the mutual relationship of SDs and chromatin topology. RESULTS: Intrachromosomal SDs preferentially accumulate in those segments of chromosome 7 that are homologous to marmoset chromosome 2. Although this formerly compact segment has been re-distributed to three different sites during primate evolution, we can show by means of public data on long distance chromatin interactions that these three intervals, and consequently the paralogous SDs mapping to them, have retained their spatial proximity in the nucleus. Focusing on SD clusters implicated in the aetiology of the Williams-Beuren syndrome locus we demonstrate by cross-species comparison that these SDs have inserted at the borders of a topological domain and that they flank regions with distinct DNA conformation. CONCLUSIONS: Our study suggests a link of nuclear architecture and the propagation of SDs across chromosome 7, either by promoting regional SD insertion or by contributing to the establishment of higher order chromatin organisation themselves. The latter could compensate for the high risk of structural rearrangements and thus may have contributed to their evolutionary fixation in the human genome.


Asunto(s)
Cromatina/genética , Cromosomas Humanos Par 7 , Duplicaciones Segmentarias en el Genoma , Acetilación , Cromatina/metabolismo , Cromosomas Humanos Par 2 , Epistasis Genética , Evolución Molecular , Sitios Genéticos , Genómica , Histonas/metabolismo , Humanos , Transcripción Genética , Síndrome de Williams/genética
12.
J Med Genet ; 51(6): 375-87, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24714694

RESUMEN

BACKGROUND: NKX2-1 encodes a transcription factor with large impact on the development of brain, lung and thyroid. Germline mutations of NKX2-1 can lead to dysfunction and malformations of these organs. Starting from the largest coherent collection of patients with a suspected phenotype to date, we systematically evaluated frequency, quality and spectrum of phenotypic consequences of NKX2-1 mutations. METHODS: After identifying mutations by Sanger sequencing and array CGH, we comprehensively reanalysed the phenotype of affected patients and their relatives. We employed electrophoretic mobility shift assay (EMSA) to detect alterations of NKX2-1 DNA binding. Gene expression was monitored by means of in situ hybridisation and compared with the expression level of MBIP, a candidate gene presumably involved in the disorders and closely located in close genomic proximity to NKX2-1. RESULTS: Within 101 index patients, we detected 17 point mutations and 10 deletions. Neurological symptoms were the most consistent finding (100%), followed by lung affection (78%) and thyroidal dysfunction (75%). Novel symptoms associated with NKX2-1 mutations comprise abnormal height, bouts of fever and cardiac septum defects. In contrast to previous reports, our data suggest that missense mutations in the homeodomain of NKX2-1 not necessarily modify its DNA binding capacity and that this specific type of mutations may be associated with mild pulmonary phenotypes such as asthma. Two deletions did not include NKX2-1, but MBIP, whose expression spatially and temporarily coincides with NKX2-1 in early murine development. CONCLUSIONS: The high incidence of NKX2-1 mutations strongly recommends the routine screen for mutations in patients with corresponding symptoms. However, this analysis should not be confined to the exonic sequence alone, but should take advantage of affordable NGS technology to expand the target to adjacent regulatory sequences and the NKX2-1 interactome in order to maximise the yield of this diagnostic effort.


Asunto(s)
Enfermedades Genéticas Congénitas , Proteínas Nucleares/genética , Factores de Transcripción/genética , Adolescente , Niño , Preescolar , Hibridación Genómica Comparativa , Variaciones en el Número de Copia de ADN/genética , Ensayo de Cambio de Movilidad Electroforética , Femenino , Eliminación de Gen , Enfermedades Genéticas Congénitas/genética , Enfermedades Genéticas Congénitas/fisiopatología , Humanos , Lactante , Recién Nacido , Masculino , Fenotipo , Mutación Puntual/genética , Factor Nuclear Tiroideo 1
13.
J Mol Microbiol Biotechnol ; 24(1): 19-36, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24158107

RESUMEN

Analysis of the completely determined genomes of the plant-derived Acholeplasma brassicae strain O502 and A. palmae strain J233 revealed that the circular chromosomes are 1,877,792 and 1,554,229 bp in size, have a G + C content of 36 and 29%, and encode 1,690 and 1,439 proteins, respectively. Comparative analysis of these sequences and previously published genomes of A. laidlawii strain PG-8, 'Candidatus Phytoplasma asteris' strains, 'Ca. P. australiense' and 'Ca. P. mali' show a limited shared basic genetic repertoire. The acholeplasma genomes are characterized by a low number of rearrangements, duplication and integration events. Exceptions are the unusual duplication of rRNA operons in A. brassicae and an independently introduced second gene for a single-stranded binding protein in both genera. In contrast to phytoplasmas, the acholeplasma genomes differ by encoding the cell division protein FtsZ, a wide variety of ABC transporters, the F0F1 ATP synthase, the Rnf-complex, SecG of the Sec-dependent secretion system, a richly equipped repertoire for carbohydrate metabolism, fatty acid, isoprenoid and partial amino acid metabolism. Conserved metabolic proteins encoded in phytoplasma genomes such as the malate dehydrogenase SfcA, several transporters and proteins involved in host-interaction, and virulence-associated effectors were not predicted for the acholeplasmas.


Asunto(s)
Acholeplasmataceae/genética , ADN Bacteriano/química , ADN Bacteriano/genética , Genoma Bacteriano , Análisis de Secuencia de ADN , Acholeplasmataceae/aislamiento & purificación , Proteínas Bacterianas/genética , Composición de Base , Orden Génico , Datos de Secuencia Molecular , Phytoplasma/genética , Sintenía
14.
J Lipid Res ; 54(11): 3170-6, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24023261

RESUMEN

Although numerous genes are known to regulate serum lipid traits, identified variants explain only a small proportion of the expected heritability. We intended to identify further genetic variants associated with lipid phenotypes in a self-contained population of Sorbs in Germany. We performed a genome-wide association study (GWAS) on LDL-cholesterol, HDL-cholesterol (HDL-C), and triglyceride (TG) levels in 839 Sorbs. All single-nucleotide polymorphisms with a P value <0.01 were subjected to a meta-analysis, including an independent Swedish cohort (Diabetes Genetics Initiative; n = ∼3,100). Novel association signals with the strongest effects were subjected to replication studies in an additional German cohort (Berlin, n = 2,031). In the initial GWAS in the Sorbs, we identified 14 loci associated with lipid phenotypes reaching P values <10⁻5 and confirmed significant effects for 18 previously reported loci. The combined meta-analysis of the three study cohorts (n(HDL) = 6041; n(LDL) = 5,995; n(TG) = 6,087) revealed a novel association for a variant in THOC5 (rs8135828) with serum HDL-C levels (P = 1.78 × 10⁻7; Z-score = -5.221). Consistently, the variant was also associated with circulating APOA1 levels in Sorbs. The small interfering RNA-mediated mRNA silencing of THOC5 in HepG2 cells resulted in lower mRNA levels of APOA1, SCARB1, and ABCG8 (all P < 0.05). We propose THOC5 to be a novel gene involved in the regulation of serum HDL-C levels.


Asunto(s)
HDL-Colesterol/metabolismo , Proteínas Nucleares/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Estudio de Asociación del Genoma Completo , Alemania/etnología , Células Hep G2 , Humanos , Masculino , Metaanálisis como Asunto , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , ARN Mensajero/genética , ARN Mensajero/metabolismo , Adulto Joven
15.
Brain Behav ; 3(5): 495-502, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24392270

RESUMEN

INTRODUCTION: The glutamate receptor, metabotropic 8 gene (GRM8) encodes a G-protein-coupled glutamate receptor and has been associated with smoking behavior and liability to alcoholism implying a role in addiction vulnerability. Data from animal studies suggest that GRM8 may be involved in the regulation of the neuropeptide Y and melanocortin pathways and might influence food intake and metabolism. This study aimed to investigate the effects of the genetic variant rs2237781 within GRM8 on human eating behavior. METHODS: The initial analysis included 548 Sorbs from Germany who have been extensively phenotyped for metabolic traits and who completed the German version of the three-factor eating questionnaire. In addition, we analyzed two independent sample sets comprising 293 subjects from another German cohort and 430 Old Order Amish individuals. Genetic associations with restraint, disinhibition, and hunger were assessed in an additive linear regression model. RESULTS: Among the Sorbs the major G allele of rs2237781 was significantly associated with increased restraint scores in eating behavior (P = 1.9 × 10(-4); ß = +1.936). The German cohort and the Old Order Amish population revealed a trend in the same direction for restraint (P = 0.242; ß = +0.874; P = 0.908; ß = +0.096; respectively). A meta-analysis resulted in a combined P = 3.1 × 10(-3) (Z-score 2.948). CONCLUSION: Our data suggest that rs2237781 within GRM8 may influence human eating behavior factors probably via pathways involved in addictive behavior.

16.
J Virol ; 86(19): 10444-55, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22811533

RESUMEN

Shiga toxin 2 (Stx2)-producing Escherichia coli (STEC) O104:H4 caused one of the world's largest outbreaks of hemorrhagic colitis and hemolytic uremic syndrome in Germany in 2011. These strains have evolved from enteroaggregative E. coli (EAEC) by the acquisition of the Stx2 genes and have been designated enteroaggregative hemorrhagic E. coli. Nucleotide sequencing has shown that the Stx2 gene is carried by prophages integrated into the chromosome of STEC O104:H4. We studied the properties of Stx2-encoding bacteriophages which are responsible for the emergence of this new type of E. coli pathogen. For this, we analyzed Stx bacteriophages from STEC O104:H4 strains from Germany (in 2001 and 2011), Norway (2006), and the Republic of Georgia (2009). Viable Stx2-encoding bacteriophages could be isolated from all STEC strains except for the Norwegian strain. The Stx2 phages formed lysogens on E. coli K-12 by integration into the wrbA locus, resulting in Stx2 production. The nucleotide sequence of the Stx2 phage P13374 of a German STEC O104:H4 outbreak was determined. From the bioinformatic analyses of the prophage sequence of 60,894 bp, 79 open reading frames were inferred. Interestingly, the Stx2 phages from the German 2001 and 2011 outbreak strains were found to be identical and closely related to the Stx2 phages from the Georgian 2009 isolates. Major proteins of the virion particles were analyzed by mass spectrometry. Stx2 production in STEC O104:H4 strains was inducible by mitomycin C and was compared to Stx2 production of E. coli K-12 lysogens.


Asunto(s)
Bacteriófagos/genética , Escherichia coli/metabolismo , Toxina Shiga II/metabolismo , Adulto , Secuencia de Aminoácidos , Niño , Femenino , Georgia (República) , Alemania , Humanos , Lisogenia , Masculino , Espectrometría de Masas/métodos , Microscopía Electrónica de Transmisión/métodos , Mitomicina/química , Datos de Secuencia Molecular , Myoviridae/metabolismo , Noruega , Análisis de Secuencia de ADN , Escherichia coli Shiga-Toxigénica/metabolismo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Virión
17.
Appl Environ Microbiol ; 78(13): 4732-9, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22544244

RESUMEN

To advance the understanding of the molecular mechanisms controlling microbial activities involved in carbon cycling and mitigation of environmental pollution in freshwaters, the influence of heavy metals and natural as well as xenobiotic organic compounds on laccase gene expression was quantified using quantitative real-time PCR (qRT-PCR) in an exclusively aquatic fungus (the aquatic hyphomycete Clavariopsis aquatica) for the first time. Five putative laccase genes (lcc1 to lcc5) identified in C. aquatica were differentially expressed in response to the fungal growth stage and potential laccase inducers, with certain genes being upregulated by, e.g., the lignocellulose breakdown product vanillic acid, the endocrine disruptor technical nonylphenol, manganese, and zinc. lcc4 is inducible by vanillic acid and most likely encodes an extracellular laccase already excreted during the trophophase of the organism, suggesting a function during fungal substrate colonization. Surprisingly, unlike many laccases of terrestrial fungi, none of the C. aquatica laccase genes was found to be upregulated by copper. However, copper strongly increases extracellular laccase activity in C. aquatica, possibly due to stabilization of the copper-containing catalytic center of the enzyme. Copper was found to half-saturate laccase activity already at about 1.8 µM, in favor of a fungal adaptation to low copper concentrations of aquatic habitats.


Asunto(s)
Ascomicetos/enzimología , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Lacasa/biosíntesis , Manganeso/metabolismo , Fenoles/metabolismo , Ácido Vanílico/metabolismo , Zinc/metabolismo , Ascomicetos/efectos de los fármacos , Ascomicetos/genética , Cobre/metabolismo , ADN de Hongos/química , ADN de Hongos/genética , Perfilación de la Expresión Génica , Datos de Secuencia Molecular , Reacción en Cadena en Tiempo Real de la Polimerasa , Análisis de Secuencia de ADN
18.
Pharmacogenomics ; 12(8): 1119-26, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21830867

RESUMEN

AIMS: Mutations in the sodium-glucose cotransporter 2 (SGLT2), as well as treatment with SGLT2 inhibitors result in reduced fasting glucose levels, HbA(1c) and BMI. We therefore investigated the effects of common genetic variation in SGLT2 on human Type 2 diabetes and related traits. MATERIALS & METHODS: Four HapMap tagging SNPs covering the common genetic variation in SGLT2 (r² > 0.8 and minor allele frequency > 0.01) were genotyped for subsequent association studies on BMI, Type 2 diabetes and related metabolic traits in 1013 Sorbs (Germany). An independent cohort from Berlin (n = 2042) was taken for replication. RESULTS: The rs9934336 G-allele was nominally associated with increased 30-min plasma glucose, 120-min insulin concentrations and AUC120min(glucose) during oral glucose tolerance test in 907 nondiabetic Sorbs (p < 0.05). In the combined analysis including the Sorbs and the Berlin cohort, rs9934336 was nominally associated with 120-min insulin concentrations (adjusted p < 0.05) in nondiabetic subjects (n = 2590). CONCLUSION: Our data suggest a role of SGLT2 genetic variation in the regulation of glucose homeostasis and promote pharmacogenomic studies to clarify the efficacy of antidiabetic treatment by SGLT2 inhibitors.


Asunto(s)
Glucemia/genética , Homeostasis/genética , Transportador 2 de Sodio-Glucosa/genética , Anciano , Área Bajo la Curva , Glucemia/fisiología , Índice de Masa Corporal , Estudios de Cohortes , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Femenino , Frecuencia de los Genes , Variación Genética , Alemania/epidemiología , Prueba de Tolerancia a la Glucosa , Homeostasis/fisiología , Humanos , Insulina/sangre , Masculino , Persona de Mediana Edad , Fenotipo , Polimorfismo de Nucleótido Simple
19.
J Immunol ; 186(9): 5478-88, 2011 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-21441453

RESUMEN

In macrophages, two signaling pathways, dependent on MyD88 or TIR domain-containing adaptor-inducing IFN-ß (TRIF) signaling, emanate from the LPS receptor TLR4/MD-2. In this study, we show that in murine bone marrow-derived mast cells (BMMCs), only the MyD88-dependent pathway is activated by LPS. The TRIF signaling branch leading both to NF-κB activation and enhanced proinflammatory cytokine production, as well as to IRF3 activation and subsequent IFN-ß production, is absent in LPS-stimulated BMMCs. IRF3 activation is also absent in peritoneal mast cells from LPS-injected mice. We observed strongly diminished TRAM expression in BMMCs, but overexpression of TRAM only moderately enhanced IL-6 and did not boost IFN-ß responses to LPS in these cells. A combination of very low levels of TRAM and TLR4/MD-2 with the known absence of membrane-bound CD14 are expected to contribute to the defective TRIF signaling in mast cells. We also show that, unlike in macrophages, in BMMCs the TRIF-dependent and -independent IFN-αß responses to other recognized IFN inducers (dsRNA, adenovirus, and B-DNA) are absent. These results show how the response to the same microbial ligand using the same receptor can be regulated in different cell types of the innate immune system.


Asunto(s)
Proteínas Adaptadoras del Transporte Vesicular/inmunología , Lipopolisacáridos/inmunología , Mastocitos/inmunología , Transducción de Señal/inmunología , Proteínas Adaptadoras Transductoras de Señales , Animales , Western Blotting , Separación Celular , Inmunoprecipitación de Cromatina , Citocinas/biosíntesis , Citocinas/inmunología , Citometría de Flujo , Antígeno 96 de los Linfocitos , Ratones , Ratones Endogámicos C57BL , Receptores de Interleucina/inmunología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Receptor Toll-Like 4 , Transfección
20.
Stroke ; 41(12): 2918-23, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21071720

RESUMEN

BACKGROUND AND PURPOSE: Aneurysmal subarachnoid hemorrhage (SAH) is a cerebrovascular disease with a high mortality rate and severe disability. Longitudinal studies investigating health-economic costs in SAH are scare and only one of them analyzed cost-driving factors. The objective was to evaluate first-year costs in German patients with aneurysmal SAH and to identify independent determinants of costs. METHODS: One hundred thirteen incident cases of aneurysmal SAH treated in the Department of Neurosurgery and Neuroradiology at the University of Bonn (catchment area of 500,000 people) between January 2004 and December 2005 were eligible for the study. Cost data were collected using health-economic questionnaires applied at baseline and 6- and 12-month follow-up time. All costs are expressed in (year 2009 values). Clinical assessments were performed using Hunt and Hess scale, Barthel Index, and Rankin Scale. Independent cost-driving factors were determined using multiple regression analysis. RESULTS: The total first-year costs were 38,300 (95% CI, 34 490 to 43,100) per patient. Direct costs accounted for 58.7% of total costs and were mainly paid by the health insurance (92.0%). Inpatient costs were the main cost component of direct and total costs (42.8% of total costs). The major cost-driving factors of total costs were younger age and worse functional outcome at 12-month follow-up (Barthel Index). CONCLUSIONS: Aneurysmal SAH is a cerebrovascular disease with considerable health-economic burden. Healthcare programs aimed at reducing the burden of SAH on society and individuals should consider cost-driving factors of SAH. Further health-economic studies investigating cost-driving factors of SAH in different countries are needed.


Asunto(s)
Hemorragia Subaracnoidea/economía , Adulto , Anciano , Costo de Enfermedad , Femenino , Alemania , Humanos , Seguro de Salud/economía , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Factores Socioeconómicos
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