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 SamplesTo study the gene expression profile of salivary glands with varying degrees of inflammation in Sjogren's and non Sjogren's patients
Chitinases in the salivary glands and circulation of patients with Sjögren's syndrome: macrophage harbingers of disease severity.
Specimen part, Disease
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 SamplesEstrogen receptor positive (ER+) breast cancers that develop resistance to therapies that target the ER are the most common cause of breast cancer death. Beyond mutations in ER, which occur in 25-30% of patients treated with aromatase inhibitors (AIs), our understanding of clinical mechanisms of resistance to ER-directed therapies remains incomplete. We identified activating HER2 mutations in metastatic biopsies from eight patients with ER+ metastatic breast cancer who had developed resistance to ER-directed agents, including AIs, tamoxifen, and fulvestrant. Examination of treatment-naïve primary tumors in five patients revealed no evidence of pre-existing mutations in four of five patients, suggesting that these mutations were acquired under the selective pressure of ER-directed therapy. These mutations were mutually exclusive with ER mutations, suggesting a distinct mechanism of acquired resistance to ER-directed therapies. In vitro analysis confirmed that these mutations conferred estrogen independence. In addition, and in contrast to ER mutations, these mutations resulted in resistance to tamoxifen, fulvestrant, and the CDK4/6 inhibitor palbociclib. Resistance was overcome by combining ER-directed therapy with the irreversible HER2 kinase inhibitor neratinib, highlighting an effective treatment strategy in these patients. Overall design: Examination of the transcriptional output (mRNA) of the HER2 activating mutations compared with controls under various drugs. Specifically, we expressed the activating mutations S653C, L755S, V777L, and L869R in ER+/HER2- breast cancer cell line (T47D), and controls (GFP, wild-type HER2, kinase-dead HER2, and ESR1 Y537S). Cell were then treated with DMSO, 1µM fulvestrant, 1µM neratinib, 10µM palbociclib, 1µM fulvestrant + 1µM neratinib, or 1µM fulvestrant + 10µM palbociclib for 24 hours. All experimental conditions were done in 6 replicates, sequenced in 3 replicates
Acquired HER2 mutations in ER<sup>+</sup> metastatic breast cancer confer resistance to estrogen receptor-directed therapies.
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View SamplesHomeobox genes of the Hox class are required for proper patterning of skeletal elements and play a role in cartilage differentiation. In transgenic mice with overexpression of Hoxd4 during cartilage development, we observed severe defects, namely physical instability of cartilage, accumulation of immature chondrocytes, and decreased maturation to hypertrophy. To define the molecular basis underlying these defects, we performed gene expression profiling using the Affymetrix microarray platform.
Microarray Analysis of Defective Cartilage in Hoxc8- and Hoxd4-Transgenic Mice.
Specimen part
View SamplesHomeobox genes of the Hox class are required for proper patterning of skeletal elements and play a role in cartilage differentiation. In transgenic mice with overexpression of Hoxc8 during cartilage development, we observed severe defects, namely physical instability of cartilage, accumulation of immature chondrocytes, and decreased maturation to hypertrophy. To define the molecular basis underlying these defects, we performed gene expression profiling using the Affymetrix microarray platform.
Microarray Analysis of Defective Cartilage in Hoxc8- and Hoxd4-Transgenic Mice.
Specimen part
View SamplesAnalysis of gene expression data in two C.elegans mutant strains: KP3293 tom-1(nu468) and KP3365 unc-43(n1186); hif-1(nu469). These results support the utility of microarray hybridizations to facilitate positional cloning.
Using microarrays to facilitate positional cloning: identification of tomosyn as an inhibitor of neurosecretion.
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View SamplesDiabetic embryopathy can affect any developing organ system, although cardiovascular malformations, neural tube defects and caudal dysgenesis syndrome are the most prominent congenital malformations. We hypothesize that the metabolic imbalance occurring in diabetic pregnancy de-regulates tissue specific gene expression programs in the developing embryo. In order to identify genes whose expression is affected by maternal diabetes, we analyzed gene expression profiles of diabetes-exposed mouse embryos by using Affymetrix microarrays. We identified 129 genes with altered expression levels; 21 genes had increased and 108 genes had decreased expression levels in diabetes-exposed embryos relative to controls. A substantial fraction of these genes (35) are essential for normal embryonic development as shown by functional studies in mouse models. The largest fraction of diabetes-affected genes was in transcription factor and DNA-binding/chromatin remodeling functional categories (19%), which directly affect transcription. These findings suggest that transcriptional regulation in the developing embryos is perturbed by maternal diabetes and that transcriptional regulation plays a major role in the responses of embryos to intrauterine exposure to diabetic conditions. Interestingly, we found the expression of hypoxia-inducible factor 1 (Hif1) deregulated in the embryos exposed to the conditions of maternal diabetes. Since hypoxic stress is associated with the complications of diabetic pregnancy, we performed a post-hoc analysis of our microarray data with a specific focus on known HIF1 target genes. Of 39 genes detected in our microarrays, the expression changes of 22 genes (20 were increased and two genes were decreased in diabetes-exposed embryos) were statistically significant. These results indicate that HIF1-regulated pathways are affected in diabetes-exposed embryos. These results strongly suggest that de-regulation of hypoxia/HIF1 activated pathways could be the one of the key molecular events associated with the exposure to the teratogenic intrauterine environment of a diabetic mother.
Maternal diabetes alters transcriptional programs in the developing embryo.
Specimen part
View SamplesExposure to maternal diabetes during pregnancy alters transcriptional profiles in the developing embryo. The enrichment, within the set of de-regulated genes, of those encoding transcriptional regulatory molecules provides support for the hypothesis that maternal diabetes affects specific developmental programs.
Maternal diabetes alters transcriptional programs in the developing embryo.
Specimen part, Disease, Disease stage
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