We have observed that follicular B cells from mice with a hypomorphic mutation (IkL/L) in the Ikzf1 gene (which encodes the Ikaros transcription factor) exhibit an increased proliferative response to anti-IgM stimulation (Kirstetter et al, Eur J Immunol, 32:720-30, 2002). We asked if Ikaros controls the transcriptional response that unfolds after activation, or if differences in the transcriptional landscape of resting B cells could explain the altered response. To this end, we have determined the transcriptome of unstimulated WT and IkL/L follicular B cells, as well as that of cells stimulated for 3h and 12h with anti-IgM. Samples from 2 independent experients were analyzed.
Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways.
Age, Specimen part
View SamplesInherited genetic risk factors play an important role in cancer. However, other than cancer susceptibility genes found in familial cancer syndromes and inherited in a Mendelian fashion, little is known about modifier genes (germline variants that interact with each other and with environmental factors) that contribute to individual susceptibility. Here we develop a strategy parental strain expression mapping (PSEM), which utilizes the homogeneity of inbred mice and genome-wide mRNA expression analyses, to directly identify candidate germline modifier genes and pathways underlying phenotypic differences among murine strains exposed to transgenic activation of AKT1. We identified multiple candidate modifier pathways and specifically, the glycolysis pathway as a candidate negative modulator of AKT1-induced proliferation. In keeping with findings in murine models, the expression of the glycolysis pathway was strongly enriched in the non-cancer prostate tissue from patients with prostate cancer who did not recur after surgical resection. Together these data suggest that PSEM can directly identify germline modifier pathways of relevance to human disease.
Identification of prostate cancer modifier pathways using parental strain expression mapping.
Age
View SamplesGlobal restriction of protein synthesis is a hallmark of cellular stress. Using hydrogen peroxide, we monitor the transcript level and also the translation status for each RNA using cycloheximide to freeze elongating ribosomes. Polyribosome fractionation of cell extracts was used to separate highly translated and poorly translated mRNAs that were then separately analysed.
Global translational responses to oxidative stress impact upon multiple levels of protein synthesis.
Sex, Compound
View SamplesHistologic diagnosis of T cell-mediated rejection in kidney transplant biopsies has limited reproducibility because it is based on non-specific lesions using arbitrary rules that are subject to differing interpretations. We used microarray results from 403 indication biopsies previously given histologic diagnoses to develop a molecular classifier that assigned a molecular T cell-mediated rejection score to each biopsy. Independent assessment of the biopsies by multiple pathologists confirmed considerable disagreement on the presence of TCMR features: 79-88% accuracy and 35-69% sensitivity. The agreement of the molecular T cell-mediated rejection score with the histology diagnosis was similar to agreement among individual pathologists: accuracy 89%, sensitivity 51%. However, the score also predicted the consensus among pathologists, being highest when all agreed. Many discrepancies between the scores and the histologic diagnoses were in situations where histology is unreliable e.g. scarred biopsies. The score correlated with histologic lesions and gene sets associated with T cell-mediated rejection. The transcripts most often selected by the classifier were expressed in effector T cells, dendritic cells, or macrophages or inducible by interferon-gamma. Thus the T cell-mediated rejection score offers an objective assessment of kidney transplant biopsies, predicting the consensus opinion among multiple pathologists, and offering insights into underlying disease mechanisms.
Molecular diagnosis of T cell-mediated rejection in human kidney transplant biopsies.
Disease
View SamplesThe capability to detect target organ toxicity as well as to determine the molecular mechanisms underlying such toxicity by employing surrogate biospecimens that can be obtained by a non-invasive or minimally invasive procedure has significant advantage in occupational toxicology. Pulmonary toxicity and global gene expression profile in the lungs, peripheral blood and bronchoalveolar lavage (BAL) cells were determined in rats at 44-weeks following pulmonary exposure to crystalline silica (15 mg/m3, 6-hours/day, 5 days). A significant elevation in lactate dehydrogenase activity and albumin content observed in the BAL fluid suggested the induction of pulmonary toxicity in the silica exposed rats. Similarly, the observation of histological alterations, mainly type II pneumocyte hyperplasia and fibrosis, in the lungs further confirmed silica-induced pulmonary toxicity in the rats. A significant increase in the number of neutrophils and elevated monocyte chemotactic protein 1 level in the BAL fluids suggested silica-induced pulmonary inflammation in the rats. Determination of global gene expression profile in the lungs, BAL cells, and peripheral blood of the silica exposed rats identified 144, 236, and 51 significantly differentially expressed genes (SDEGs), respectively, compared with the corresponding control samples. Bioinformatics analysis of the SDEGs demonstrated a remarkable similarity in the biological functions, molecular networks and canonical pathways that were significantly affected by silica exposure in the lungs, BAL cells and blood of the rats. Induction of inflammation was identified, based on the bioinformatics analysis of the significantly differentially expressed genes in the lungs, blood and BAL cells, as the major molecular mechanism underlying the silica-induced pulmonary toxicity. The findings of our study demonstrated the potential application of global gene expression profiling of peripheral blood and BAL cells as a valuable minimally invasive approach to study silica-induced pulmonary toxicity in rats.
Molecular mechanisms of pulmonary response progression in crystalline silica exposed rats.
Sex, Specimen part, Time
View SamplesFibroblasts from patients with Type I bipolar disorder (BPD) and their unaffected siblings were obtained from an Old Order Amish pedigree with a high incidence of BPD and reprogrammed to induced pluripotent stem cells (iPSCs). Established iPSCs were subsequently differentiated into neuroprogenitors (NPs) and then to neurons. Transcriptomic microarray analysis was conducted on RNA samples from iPSCs, NPs and neurons matured in culture for either 2 weeks (termed early neurons, E) or 4 weeks (termed late neurons, L). Global RNA profiling indicated that BPD and control iPSCs differentiated into NPs and neurons at a similar rate, enabling studies of differentially expressed genes in neurons from controls and BPD cases. Significant disease-associated differences in gene expression were observed only in L neurons. Specifically, 328 genes were differentially expressed between BPD and control L neurons including GAD1, glutamate decarboxylase 1 (2.5 fold) and SCN4B, the voltage gated type IV sodium channel beta subunit (-14.6 fold). Quantitative RT-PCR confirmed the up-regulation of GAD1 in BPD compared to control L neurons. Gene Ontology, GeneGo and Ingenuity Pathway Analysis of differentially regulated genes in L neurons suggest that alterations in RNA biosynthesis and metabolism, protein trafficking as well as receptor signaling pathways GSK3 signaling may play an important role in the pathophysiology of BPD.
Transcriptomic Analysis of Induced Pluripotent Stem Cells Derived from Patients with Bipolar Disorder from an Old Order Amish Pedigree.
Specimen part, Disease, Disease stage
View SamplesPurpose: Conducted expression profiling by RNA-seq as unbiased screen to identify genes that are altered in motor neurons of PbxMN? mice at e12.5 at brachial and thoracic levels of the spinal cord. Because loss of Pbx genes affects MN organization at all rostrocaudal levels, we focused on genes whose profiles were altered at both brachial and thoracic levels. Methods: We compared gene expression profiles in MNs isolated from control Hb9::GFP and PbxMN?; Hb9::GFP embryos at e12.5. MNs were purified by FACS, and RNA was extracted from 9 PbxMN?; Hb9::GFP and 9 control Hb9::GFP embryos at brachial and thoracic levels using the Arcturus Picopure RNA isolation kit. 10ng of RNA was pooled from 3 RNA samples of each genotype, and used to amplify 100ng of cDNA using Nugene''s Ovation RNA-Seq System V2 kit, 100ng of cDNA for each sample was used as in input to prepare 12 bar coded libraries using the Ovation Ultralow Library system. We then performed expression profiling by RNA-seq. The samples were mixed into two pools and run on two 50-nucleotide paired end read rapid run flow cell lanes with the Illumina HiSeq 2500 sequencer. Generating on average 74 and 101 million reads passing filter for brachial and thoracic samples respectively. Results: This analysis yielded 64 brachial and 124 thoracic genes that were differentially expressed with a stringent cutoff of padj.<0.05. Of these genes, we found 31 genes in common between the two, brachial and thoracic, levels of the spinal cord that may play a role in motor neuron columnar organization. Furthermore our expression profiling of control brachial and control thoracic MNs identified 61 genes with (padj.<0.05), that represent distinct molecular profiles of MNs generated at brachial and thoracic levels which may be used to further characterize MNs involved in forelimb and thoracic innervation. Conclusions: Our study represents a detailed transcriptional analysis of embryonic spinal motor neurons and revealed a number of novel motor neuron-specific genes that are under transcriptional regulation of Pbx genes. Overall design: Examination of embryonic spinal MN expression profiles at 2 different spinal cord levels, brachial and thoracic. From RNA collected from 9 pooled Control and 9 PbxMN? e12.5 Hb9::GFP FACS MNs.
Parallel Pbx-Dependent Pathways Govern the Coalescence and Fate of Motor Columns.
Specimen part, Cell line, Subject
View SamplesThe experiment aimed at determining the genes that are under the control of the Ikaros transcription factor in mouse splenic B1 and B2 B lymphocyte subsets. To this aim, we used Ikf/f R26-CreERT2+ (Cre+) or Ikf/f R26-CreERT2- (Cre-) mice, which correspond to mice with floxed null alleles for Ikzf1 (Heizmann et al., JEM 210:2823-32, 2013) that were crossed with the R26-CreERT2 mice, which harbor a knock-in of the cDNA encoding the tamoxifen (TAM) inducible CreERT2 recombinase in the Rosa26 gene (Badea et al, J. Neurosci 23:2314-22, 2003). 6-8 week-old mice were injected daily with TAM for 3d (50mg/kg). Mice were sacrificed 10d after the first injection, and splenic B1 and B2 B cell populations sorted by flow cytometry.
Ikaros Is a Negative Regulator of B1 Cell Development and Function.
Sex, Specimen part
View SamplesMicroarray analysis of human kidneys with acute kidney injury (AKI) has been limited because such kidneys are seldom biopsied. However, all kidney transplants experience AKI, and early kidney transplants without rejection are an excellent model for human AKI: they are screened to exclude chronic kidney disease, frequently biopsied, and have extensive follow-up. We used histopathology and microarrays to compare indication biopsies from 28 transplants with AKI to 11 pristine protocol biopsies of stable transplants. Kidneys with AKI showed increased expression of 394 injury-repair response associated transcripts, including many known epithelial injury molecules (e.g. ITGB6, LCN2), tissue remodeling molecules (e.g. VCAN), and inflammation molecules (S100A8, ITGB3). Many other genes also predict the phenotype, depending on statistical filtering rules, including AKI biomarkers as HAVCR1 and IL18. Most mouse orthologs of the top injury-repair transcripts were increased in published mouse AKI models. Pathway analysis of the injury-repair transcripts revealed similarities to cancer, development, and cell movement. The injury-repair transcript score AKI kidneys correlated with reduced function, future recovery, brain death, and need for dialysis, but not future graft loss. In contrast, histologic features of "acute tubular injury" did not correlate with function or with the molecular changes. Thus the injury-repair associated transcripts represent a massive coordinate injury-repair response of kidney parenchyma to AKI, similar to mouse AKI models, and provide an objective measure for assessing the severity of AKI in kidney biopsies and validation for the use of many AKI biomarkers.
Molecular phenotypes of acute kidney injury in kidney transplants.
Specimen part, Disease
View SamplesOne common form of translational control is mediated by proteins that bind to the mRNA 5' cap-binding protein eIF4E. These proteins are collectively called 4E binding proteins (4EBPs). Saccharomyces cerevisiae possesses two 4EBPs that are encoded by non-essential genes called CAF20 and EAP1. To determine the impact of gene deletion on gene expression, we monitored the transcript level and also the translation status for each RNA using cycloheximide to freeze elongating ribosomes in wild-type, caf20 and eap1 cells. Polyribosome fractionation of cell extracts was used to separate highly translated and poorly translated mRNAs that were then separately analyzed.
Identifying eIF4E-binding protein translationally-controlled transcripts reveals links to mRNAs bound by specific PUF proteins.
Sex
View Samples