Rheumatoid arthritis (RA) leads to progressive destruction of articular structures. Despite recent progress in controlling inflammation and pain, little cartilage repair has yet been observed. This in vitro study aims to determine the role of chondrocytes in RA-related cartilage destruction and antirheumatic drug-related regenerative processes. Human chondrocytes were three-dimensionally cultured in alginate beads. To determine the RA-induced gene expression pattern, human chondrocytes were stimulated with supernatant of RA synovial fibroblasts (RASF) and normal donor synovial fibroblasts (NDSF), respectively. To examine antirheumatic drug response signatures, human chondrocytes were stimulated with supernatant of RASF that have been treated with disease-modifying antirheumatic drugs (DMARD; azathioprine, sodium aurothiomalate, chloroquine phosphate, methotrexate), non-steroidal anti-inflammatory drugs (NSAID; piroxicam, diclofenac) or steroidal anti-inflammatory drugs (SAID; methylprednisolone, prednisolone). Genome-wide expression profiling with oligonucleotide microarrays was used to determine differentially expressed genes. Real-time RT-PCR and ELISA were performed for validation of microarray data. Following antirheumatic treatment, microarray analysis disclosed a reverted expression of 94 RA-induced chondrocyte genes involved in inflammation/NF-B signalling, cytokine/chemokine activity, immune response, proliferation/differentiation and matrix remodelling. Hierarchical clustering analysis showed that treatment of RASF with the DMARD azathioprine, gold sodium thiomalate and methotrexate resulted in chondrocyte gene expression signatures that were closely related to the healthy pattern. Treatment with the SAID methylprednisolone and prednisolone strongly reverted the RA-related chondrocyte gene expression, in particular the expression of genes involved in inflammation/NF-B and cytokine/chemokine activity. The NSAID piroxicam and diclofenac and the DMARD chloroquine phosphate had only moderate to marginal effects. Pathway analysis determined major mechanisms of drug action, for example pathways of cytokine-cytokine receptor interaction, TGF-/TLR/Jak-STAT signalling and ECM-receptor interaction were targeted. This in vitro study provides a comprehensive molecular insight into the antirheumatic drug response signatures in human chondrocytes, thereby revealing potential molecular targets, pathways and mechanisms of drug action involved in chondrocyte regeneration. Thus, the present study may contribute to the development of novel therapeutic chondro-protective compounds and strategies.
Antirheumatic drug response signatures in human chondrocytes: potential molecular targets to stimulate cartilage regeneration.
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View SamplesWe have studied the expression profile of 3D cultured human chondrocytes that were stimulated with supernatant of synovial fibroblasts derived from a RA patient (RASF=HSE cell line) and from a normal donor (NDSF=K4IM cell line), respectively. For this purpose, passage 2 human chondrocytes were cultured for 14 days in alginate beads and subsequently stimulated for 48 hours with supernatant of RASF and NDSF. Baseline expression was determined of unstimulated chondrocytes. Differential genome-wide microarray analysis of RASF and NDSF stimulated chondrocytes disclosed a distinct expression profile related to cartilage destruction involving marker genes of inflammation (COX-2), NF-kappa B signaling pathway (TLR2), cytokines/chemokines and receptors (CXCL1-3, CCL20, CXCL8, CXCR4, IL-6, IL-1beta), matrix degradation (MMP-10, MMP-12) and suppressed matrix synthesis (COMP). Thus, transcriptome profiling of RASF and NDSF stimulated chondrocytes revealed a disturbed catabolic-anabolic homeostasis of chondrocyte function. This study provides a comprehensive insight into the molecular regulatory processes induced in human chondrocytes during RA-related cartilage destruction.
Key regulatory molecules of cartilage destruction in rheumatoid arthritis: an in vitro study.
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View SamplesThe aim of the study was to identify markers for the early diagnosis of endoprosthesis loosening, for the differentiation between wear-particle induced and septic loosening, as well as to gather new insights into the pathogenesis.
Gene expression in endoprosthesis loosening: chitinase activity for early diagnosis?
Sex, Age
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sex, Age, Specimen part, Treatment, Subject, Time
View SamplesThe carcinogenic potential of chemicals is currently evaluated with rodent life-time bioassays, which are time consuming, and expensive with respect to cost, number of animals and amount of compound required. For insight into early mechanisms of non-genotoxoc carcinogenesis and for identification of potential early biomarkers of non-genotoxic carcinogenesis, groups of rats were treated with a range of known non-genotoxic carcinogens for a period of 14, 28, or 90 days, and liver tissue was harvested for expression profiling. Control groups were treated with appropriate vehicles.
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sex, Specimen part, Treatment, Subject
View SamplesConventional notion regards the action of non-genotoxic carcinogens (NGC) an autonomous process largely confined to parenchymal cells. Here we aim to elucidate the role of the hepatic mesenchyme for the action of two prototypical NGC, phenobarbital (PB), an anti-epileptic drug, and cyproterone acetate (CPA) a gestagen used in contraceptive pills.
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sex, Specimen part, Treatment
View SamplesHere we investigate the difference in global gene expression in different tumor types found in the liver of rats after NNM-initiation/PB-promotion of tumor growth. We aim to identify tumor characteristic expression in nodules, focii, adenomas and carcinomas.
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sex, Specimen part, Treatment
View SamplesEvidence suggests that epigenetic perturbations are involved in the adverse effects associated with some drugs and toxicants, including certain classes of non-genotoxic carcinogens. Such epigenetic changes (altered DNA methylation and covalent histone modifications) may take place at the earliest stages of carcinogenesis and their identification holds great promise for biomedical research. Here, we evaluate the sensitivity and specificity of genome-wide epigenomic and transcriptomic profiling in phenobarbital (PB)-treated B6C3F1 mice, a well-characterized rodent model of non-genotoxic liver carcinogenesis. Methylated DNA Immunoprecipitation (MeDIP)-coupled microarray profiling of 17,967 promoter regions and 4,566 intergenic CpG islands was combined with genome-wide mRNA expression profiling to identify liver tissue-specific PB-mediated DNA methylation and transcriptional alterations. Only a limited number of significant anti-correlations were observed between PB-induced transcriptional and promoter-based DNA methylation perturbations. However, the constitutive androstane receptor (CAR) target gene Cyp2b10 was found to be concomitantly hypomethylated and transcriptionally activated in a liver tissue-specific manner following PB treatment. Furthermore, analysis of active and repressive histone modifications using chromatin immunoprecipitation revealed a strong PB-mediated epigenetic switch at the Cyp2b10 promoter. Our data reveal that PB-induced transcriptional perturbations are not generally associated with broad changes in the DNA methylation status at proximal promoters and suggest that the drug-inducible CAR pathway regulates an epigenetic switch from repressive to active chromatin at the target gene Cyp2b10. This study demonstrates the utility of integrated epigenomic and transcriptomic profiling for elucidating early mechanisms and biomarkers of non-genotoxic carcinogenesis.
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sex, Specimen part, Treatment, Subject
View SamplesSignaling through the Wnt/b-catenin pathway is a crucial determinant of hepatic zonal gene expression, liver development, regeneration, and tumorigenesis. The gene encoding b-catenin is called Ctnnb1. We have previously shown, that liver tumour promotion mediated by the model tumour promoter phenobarbital (PB) is completely lost in mice, where Ctnnb1 has been conditionally knocked out in hepatocytes (CTNNB1KO mice; Rignall et al., Carcinogenesis 32, 52-57, 2010). In the present study, the effect of a 12 weeks PB exposure on the liver miRNA expression pattern was investigated, in order to potentially get information on the nature of the loss of promotional activity in the CTNNB1KO mice.
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sex, Specimen part
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