Gene Expression Profiles from PBMC are Sensitive to Short Processing Delays
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Michael Barnes
PROVIDER: E-GEOD-21039 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:In the analysis of peripheral blood gene expression, timely processing of samples is essential to ensure that measurements reflect in vivo biology, rather than ex vivo sample processing variables. The effect of processing delays on global gene expression patterns in peripheral blood mononuclear cells (PBMC) was assessed by isolating and stabilizing PBMC-derived RNA from three individuals either immediately after phlebotomy or following a 4 hour delay. RNA was labeled using NuGEN Ovation labeling and probed using the Affymetrix HG U133plus 2.0 GeneChip®. Comparison of gene expression levels (p<0.05 and ≥ 2-fold expression change) identified 327 probe sets representing genes with increased expression and 46 indicating decreased expression after 4 hours. The trends in expression patterns associated with delayed processing were also apparent in an independent set of 276 arrays of RNA from human PBMC samples with varying processing times. These data indicate that the time between sample acquisition, initiation of processing, and when the RNA is stabilized should be a prime consideration when designing protocols for translational studies involving PBMC gene expression analysis. Keywords: Technical comparison
2011-03-22 | GSE21039 | GEO
Project description:Objective. Previous observations suggest that active systemic juvenile idiopathic arthritis (sJIA) is associated with a prominent erythropoiesis gene expression signature. The aim of this study was to determine the association of this signature with peripheral blood mononuclear cell (PBMC) subpopulations and its specificity for sJIA as compared to related conditions. 125 patients with JIA (18 sJIA and 107 non-sJIA) and 29 controls were studied. PBMC were isolated and analyzed for multiple surface antigens by flow cytometry and for gene expression profiles. The proportions of different PBMC subpopulations were compared among sJIA, non-sJIA patients and controls and subsequently correlated with the strength of the erythropoiesis signature. Additional gene expression data from patients with familial hemophagocytic lymphohistiocytosis (FHLH) and from a published sJIA cohort were analyzed to determine if the erythropoiesis signature was present. Keywords: Patient Vs Control, reassassment of phenotype Peripheral blood samples were obtained from 29 healthy children and 125 children with JIA . RNA was purified from Ficoll-isolated mononuclear cells, fluorescently labeled and then hybridized to Affymetrix U133 Plus 2.0 GeneChips. Data were analyzed using ANOVA at a 5% false discovery rate threshold after Robust Multi-Array Average pre-processing and Distance Weighted Discrimination normalization.
2010-07-30 | E-GEOD-21521 | biostudies-arrayexpress
Project description:Objective: A multi-center study of recent onset juvenile idiopathic arthritis (JIA) subjects prior to treatment with DMARDS or biologics was undertaken to identify peripheral blood gene expression differences between JIA subclasses and controls. Methods: PBMC from 59 healthy children and 136 JIA subjects (28 enthesitis-related arthritis[ERA], 42 persistent oligoarthritis, 45 RF- polyarthritis, and 21 systemic) were isolated on Ficoll. Poly-A RNA was labeled using NuGEN Ovation and gene expression profiles were obtained using Affymetrix HG-U133 plus 2.0 Arrays. Results: 9,501 differentially expressed probe sets were identified among JIA subtypes and controls (ANOVA, FDR 5%). Specifically, 193, 1036, 873 and 7595 probe sets were different between controls and ERA, persistent oligoarthritis, RF- polyarthritis and systemic JIA samples respectively. In persistent oligoarthritis, RF- polyarthritis and systemic JIA subtypes, up-regulation of gene associated with IL-10 signaling was prominent. A hemoglobin cluster was identified that was under-expressed in ERA patients but over-expressed in systemic JIA. The influence of JAK/STAT, ERK/MAPK, IL-2 and B cell receptor signaling pathways was evident in persistent oligoarthritis. In systemic JIA, up regulation of innate immune pathways, including IL-6, TLR/IL1R, and PPAR signaling were noted, along with down regulation of gene networks related to NK and T cells. Complement and coagulation pathways were up-regulated in systemic JIA with a subset of these components differentially-expressed in the other three subtypes. Conclusions: Expression analysis identified differentially expressed genes in PBMCs between subclasses of JIA early in disease and controls, thus providing evidence for immunobiologic differences between these forms of childhood arthritis. Keywords: Gene expression. PBMC. Patients compared with controls. PBMC from 59 healthy children and 136 JIA subjects (28 enthesitis-related arthritis[ERA], 42 persistent oligoarthritis, 45 RF- polyarthritis, and 21 systemic) were isolated on Ficoll. Poly-A RNA was labeled using NuGEN Ovation and gene expression profiles were obtained using Affymetrix HG-U133 plus 2.0 Arrays
2009-06-30 | E-GEOD-13501 | biostudies-arrayexpress
Project description:Objective. To identify gene expression differences in peripheral blood from patients with early and late onset juvenile idiopathic arthritis (JIA). Methods. Peripheral blood mononuclear cells (PBMC) were isolated from 56 healthy controls and 104 patients with recent onset JIA (39 persistent oligoarticular, 45 RF-polyarticular, and 20 systemic). Poly(A) RNA was amplified and labeled using NuGEN Ovation, and gene expression assessed with Affymetrix HG-U133 Plus 2.0 GeneChips®. Results. A total of 832 probe sets revealed gene expression differences (false-discovery rate 5%) in PBMC from children with oligoarticular JIA whose disease began before 6 years of age (age at onset [AaO] <6; early onset), compared to subjects whose disease began at 6 years of age or later (AaO ?6; late onset). In early onset patients there was greater expression of genes related to B-cells, and lesser expression of genes related to cells of the myeloid lineage. Support Vector Machine algorithms identified samples from early or late onset oligoarticular (97% accuracy) or polyarticular (89% accuracy) JIA patients, but not systemic JIA patients or healthy controls. Principal component analysis showed that the major classifier of samples was AaO regardless of whether they had oligoarticular or polyarticular JIA. Conclusion. PBMC gene expression analysis reveals biologic differences between early and late onset JIA patients independent of classification based on the number of joints involved. These data suggest AaO may be an important parameter to consider in JIA classification. Furthermore, different pathologic mechanisms may influence AaO, and understanding these processes may lead to improved treatment of JIA. Methods. Peripheral blood mononuclear cells (PBMC) were isolated from 56 healthy controls and 104 patients with recent onset JIA (39 persistent oligoarticular, 45 RF-polyarticular, and 20 systemic). Poly(A) RNA was amplified and labeled using NuGEN Ovation, and gene expression assessed with Affymetrix HG-U133 Plus 2.0 GeneChips®.
2011-02-14 | E-GEOD-20307 | biostudies-arrayexpress
Project description:Juvenile idiopathic arthritis (JIA) is the most common chronic childhood rheumatic disease in the Western world. To identify novel JIA predisposing loci, a genome-wide association study (GWAS) in 814 Caucasian JIA cases and 3058 Caucasian controls was completed. After adjusting for the most significant HLA associations, the strongest novel associations included rs6479891 (10q21, odds ratio (OR)=1.59, P=1.3x10-8) and rs10761747 (OR=1.34, P=4.0x10-5) within JMJD1C; rs12719740 (15q26, OR=1.47, P=3.3x10-7) near FAM169B; rs4688011 (3q13, OR=1.33, P=1.1x10-4) within C3orf1 and rs4254850 (4q31, OR=0.85, P=7.8x10-3) near IL15. Eleven SNPs were genotyped in Caucasian replication cohorts (1744 cases, 7010 controls) and meta-analysis continued to provide evidence for association with three of the SNPs (rs6479891, P=4.3x10-5; rs12719740, P=5.2x10-4; rs4688011, P=3.6x10-7). Analysis of expression data from 68 JIA cases and 23 controls overlapping in the GWAS cohort1 and published lymphoblastoid cell lines (LCL)2 showed cis eQTL associations for JMJD1C SNPs (P=0.01 and P=1.6x10-6, respectively), and the C3orf1 SNP (P=5.7x10-6). Peripheral blood samples were obtained from 23 healthy children and 68 children with JIA. RNA was purified from Ficoll-isolated mononuclear cells, fluorescently labeled and then hybridized to Affymetrix U133 Plus 2.0 GeneChips. Data were imported using Robust Multi-Array Average pre-processing and Distance Weighted Discrimination normalization. eQTL analysis were performed using genomewide association data.
2012-03-23 | E-GEOD-26554 | biostudies-arrayexpress
Project description:Familial hemophagocytic lymphohistiocytosis (FHL) is a rare, genetically heterogeneous autosomal recessive immune disorder that results when the critical regulatory pathways that mediate immune defense mechanisms and the natural termination of immune/inflammatory responses are disrupted or overwhelmed. In order to advance the understanding of FHL, we performed gene expression profiling of peripheral blood mononuclear cells (PBMCs) from 11 children with untreated FHL. Total RNA was isolated and gene expression levels were determined using microarray analysis. Comparisons between patients with FHL and normal pediatric controls (n = 30) identified 915 down-regulated and 550 up-regulated genes with 2.5-fold difference in expression (P = 0.05). The expression of genes associated with natural killer cell functions, innate and adaptive immune responses, pro-apoptotic proteins, and B- and T-cell differentiation were down-regulated in patients with FHL. Genes associated with the canonical pathways of IL-6, IL-10 IL-1, IL-8, TREM1, LXR/RXR activation, and PPAR signaling and genes encoding of anti-apoptotic proteins were overexpressed in patients with FHL. This, first study of genome-wide expression profiling in children with FHL demonstrates the complexity of gene expression patterns, which underly the immunobiology of FHL. 11 Patients and 33 controls
2011-12-12 | E-GEOD-26050 | biostudies-arrayexpress
Project description:Objective. Follistatin-like protein 1 (FSTL-1) is a secreted glycoprotein that is over-expressed in certain inflammatory diseases. Our objective in this study was to correlate FSTL-1 levels with measures of clinical disease activity in systemic juvenile idiopathic arthritis (sJIA), including macrophage activation syndrome (MAS). Methods. FSTL-1 serum levels were measured by ELISA in 28 patients with sJIA, including 7 patients who developed MAS, as well as in 30 normal controls. Levels were correlated with erythrocyte sedimentation rate (ESR), ferritin and sIL-2Rα expression. Differential gene expression based on FSTL-1 levels was analyzed in peripheral blood mononuclear cells (PBMCs). Results. FSTL-1 serum levels were elevated at time of presentation (pre-treatment) of sJIA (mean 200.7 ng/ml) and decreased to normal (mean 133.7 ng/ml) over 24 months (p<0.01). FSTL-1 levels were markedly elevated during acute MAS (mean 279.8 ng/ml) and decreased to normal (mean 120.3 ng/ml) following treatment (p<0.001). FSTL-1 levels correlated with serum markers of inflammation, including sIL-2Rα and ferritin, in patients with MAS. PBMCs from patients with FSTL-1 levels >200 ng/ml showed an increase in expression of genes related to innate immunity and erythropoiesis, and decrease in NK cell function. Patients with the highest FSTL-1 levels at disease onset (>300 ng/ml) ultimately required cyclosporine treatment. Conclusion. In patients with sJIA, serum FSTL-1 is a biomarker for MAS and FSTL-1 levels at presentation may predict subsequent disease course. Patients with FSTL-1 levels >200 ng/ml had altered gene expression patterns suggestive of subclinical MAS and may represent a subgroup of sJIA with more severe disease. FSTL-1 serum levels were measured by ELISA in 28 patients with sJIA, including 7 patients who developed MAS, as well as in 30 normal controls. Levels were correlated with erythrocyte sedimentation rate (ESR), ferritin and sIL-2Rα expression. Differential gene expression based on FSTL-1 levels was analyzed in peripheral blood mononuclear cells (PBMCs). Only 11 patients were run on microarray.
2014-01-01 | E-GEOD-38849 | biostudies-arrayexpress
Project description:Blood is one of the most common biospecimens used in clinical and translational research. However, minimizing the variability in collection and processing of human blood samples remains a challenge. Delaying plasma or serum isolation after phlebotomy (processing delay) can cause perturbations of numerous analytes used in research studies and clinical practice. We used microarrays to investigate the effects of time delay and temperature changes on whole blood transcriptomics.
2020-10-22 | GSE147788 | GEO
Project description:Objective. Microarray analysis was used to determine whether children with recent onset polyarticular juvenile idiopathic arthritis (JIA) exhibit biologically or clinically informative gene expression signatures in peripheral blood mononuclear cells (PBMC). Methods. Peripheral blood samples were obtained from 59 healthy children and 61 children with polyarticular JIA prior to treatment with second-line medications, such as methotrexate or biological agents. RNA was purified from Ficoll-isolated mononuclear cells, fluorescently labeled and then hybridized to Affymetrix U133 Plus 2.0 GeneChips. Data were analyzed using ANOVA at a 5% false discovery rate threshold after Robust Multi-Array Average pre-processing and Distance Weighted Discrimination normalization. Results. Initial analysis revealed 873 probe sets for genes that were differentially expressed between polyarticular JIA and controls. Hierarchical clustering of these probe sets distinguished three subgroups within polyarticular JIA. Prototypical subjects within each subgroup were identified and used to define subgroup-specific gene expression signatures. One of these signatures was associated with monocyte markers, another with transforming growth factor-beta-inducible genes, and a third with immediate-early genes. Correlation of these gene expression signatures with clinical and biological features of JIA subgroups suggests direct relevance to aspects of disease activity and supports the division of polyarticular JIA into distinct subsets. Conclusions. PBMC gene expression signatures in recent onset polyarticular JIA reflect discrete disease processes and offer a molecular classification of disease. Keywords: Patient vs. control, reassessment of phenotype PBMC samples were obtained from 59 healthy children and 61 children with polyarticular JIA prior to treatment with second-line medications, such as methotrexate or biological agents. RNA was purified from Ficoll-isolated mononuclear cells, fluorescently labeled and then hybridized to Affymetrix U133 Plus 2.0 GeneChips. Data were analyzed using ANOVA at a 5% false discovery rate threshold after Robust Multi-Array Average pre-processing and Distance Weighted Discrimination normalization.
2009-06-30 | E-GEOD-13849 | biostudies-arrayexpress
Project description:Phosphorylation is a dynamic, highly regulated post-translational modification that may be affected by variation in pre-analytical sample handling, hampering the translational value of phosphoproteomic-based data. Here, we investigate the temporal effect of delay in mononuclear cell isolation on acute myeloid leukemia (AML) phosphorylation profiles. We performed MS on immuno-precipitated phosphotyrosine (pY)-containing peptides isolated from AML samples after seven pre-defined delays before sample processing (direct processing, thirty minutes, one hour, two hours, three hours, four hours and 24 hours delay). Up to four hours, phosphorylation profiles showed limited variation. However, in samples processed with a delay of 24 hours, we observed significant change in phosphorylation profiles, with differential phosphorylation of 22 phosphopeptides (p < 0.01). This included increased phosphorylation of phosphopeptides of JNK and p38 kinases indicative of stress response activation. Based on these results, we conclude that processing of AML samples should be standardized at all times and should occur within four hours after sample collection.
2021-02-22 | PXD022019 | Pride