We have recently shown a remarkable regenerative capacity of the prenatal heart using a genetic model of mosaic mitochondrial dysfunction in mice. This model is based on inactivation of the X-linked gene encoding holocytochrome c synthase (Hccs) specifically in the developing heart. Loss of HCCS activity results in respiratory chain dysfunction, disturbed cardiomyocyte differentiation and reduced cell cycle activity. The Hccs gene is subjected to X chromosome inactivation, such that in females heterozygous for the heart conditional Hccs knockout approximately 50% of cardiac cells keep the defective X chromosome active and develop mitochondrial dysfunction while the other 50% remain healthy. During heart development, however, the contribution of HCCS deficient cells to the cardiac tissue decreases from 50% at midgestation to 10% at birth. This regeneration of the prenatal heart is mediated by increased proliferation of the healthy cardiac cell population, which compensate for the defective cells and allow the formation of a fully functional heart at birth. Here we performed microarray expression ananlyses on 13.5 dpc control and heterozygous Hccs knockout hearts to identify molecular mechanisms that drive embryonic heart regeneration.
Embryonic cardiomyocytes can orchestrate various cell protective mechanisms to survive mitochondrial stress.
Sex, Specimen part
View SamplesWe observed that follicular dendritic cell line induced a new type of CD11b+ myeloid cells (FDMCs) when cultured with a lineage-negative c-kit+ population from mouse spleen cells.
CSF-1 receptor-mediated differentiation of a new type of monocytic cell with B cell-stimulating activity: its selective dependence on IL-34.
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View SamplesStaphylococcus aureus is a major human pathogen and resistant to numerous clinically used antibiotics. The first antibiotic developed for S. aureus infections was the nonribosomal petide secondary metabolite penicillin. We discovered cryptic nonribosomal peptide secondary metabolites, the aureusimines, made by S. aureus itself that are not antibiotics, but function as small molecule regulators of virulence factor expression. Using established rules and codes for nonribosomal peptide assembly we predicted these nonribosomal peptides, and used these predictions to identify them from S. aureus culture broths. Functional studies using global microarray and mouse bacteremia models established that the aureusimines control virulence factor expression and are necessary for productive infections. This is the first report of the aureusimines and has important implications for the treatment of drug resistant S. aureus. Targeting aureusimine synthesis may provide novel anti-infectives.
Staphylococcus aureus nonribosomal peptide secondary metabolites regulate virulence.
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View SamplesCryopreservation consists of preserving living cells or tissues at <-100C and has many applications in, for instance, stem cell and organ banking. Cryoprotectant agents, like ethylene glycol, are required for successful cryopreservation but have toxic side effects due to largely unknown mechanisms. In this work, we studied the toxicity of ethylene glycol in Human Umbilical Vein Endothelial Cells (HUVECs). Exposing cells to 60% ethylene glycol for two hours at 4C resulted in a slight decrease in cell growth, suggesting a modest toxicity of ethylene glycol and that HUVECs do not exhibit particular sensitivity to it. Gene expression analysis with whole genome micro-arrays revealed signatures indicative of a generalized stress response at 24 hours after stress and recovery at 72 hours, involving signaling pathways, glycoproteins, and genes involved in extracellular and transmembrane functions. These results reveal a new paradigm and signatures for future experiments in elucidating the toxicity effects of ethylene glycol in vascular endothelial cells.
Insights on cryoprotectant toxicity from gene expression profiling of endothelial cells exposed to ethylene glycol.
Specimen part, Treatment
View SamplesMolecular mechanisms that influence susceptibility to multiple sclerosis are poorly understood. We conducted a gene expression study in healthy subjects that subsequently developed the disease. Gene expression profiles (HG U133A and A2, Affymetrix, 22,215 transcripts) of peripheral blood mononuclear cells were analyzed in 9 healthy subjects (mean age 19.8+1.1 years) up to 9 years (mean 5.11.2 years) before onset of MS (MS to be, MS2b), 11 age-, gender-, and origin-matched subjects that remained MS-free (MSf), and 31 clinically isolated syndrome (CIS) patients. Most informative genes (p<0.05) and significant biological processes were compared. 1051 genes (611 up-regulated, 440 down-regulated) were significantly different between MS2b and MSf subjects. MS2b signature was characterized by down-regulation of the nuclear receptor (NR) family genes including NR subfamily 4 group A member1 (NR4A1, p=0.01), member 3 (NR4A3, p=0.01), NR subfamily 2 group F member 2 (NR2F1, p=0.03) and vitamin D receptor (VDR, p=0.02), all known to be involved in T-cell regulation by apoptosis. Comparison between MS2b and CIS operating networks demonstrated evolution of the altered NR dependent apoptosis regulation. Decreased NR4A1 expression was verified at the mRNA and protein level in an independent cohort of 20 relapsing-remitting MS patients. The identified MS trait is associated with suppressed transcription of NR networks that leads to altered apoptosis of activated T cells and the development of clinical disease. MS2b subjects have already an ongoing process that eventually will lead to clinical disease and our finding are of importance as they suggest the possibility of early detection and prevention of MS.
Microarray analysis identifies altered regulation of nuclear receptor family members in the pre-disease state of multiple sclerosis.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesWe used microarray analysis to further our understanding of the mode of action of the well know caloric restriction mimetic rapamycin and the compound Allantoin first studied in the context of aging in this study. His work helps build on our understanding of potential caloric restriction mimetics predicted from our bioinformatic aproach of quering the Connectivity Map, a database of drug-induced gene expression profiles, using the transcriptional profile of CR to identify drugs that induce a similar or opposite gene expression profile.
A network pharmacology approach reveals new candidate caloric restriction mimetics in C. elegans.
Age, Specimen part
View SamplesInterferon (IFN) beta-1a is an approved treatment for relapsing remitting multiple sclerosis (RRMS) and has been examined for use in secondary progressive multiple sclerosis (SPMS). However, no information regarding blood transcriptional changes induced by IFN treatment in SPMS patients is available.
Transcriptional response to interferon beta-1a treatment in patients with secondary progressive multiple sclerosis.
Sex, Age, Treatment
View SamplesExpression of the proendocrine gene neurogenin 3 (Ngn3) is required for the development of pancreatic islets. In order to better characterize the molecular events regulated by Ngn3 during development, we have determined the expression profile of differentiating murine embryonic stem cells (mESCs) uniformly induced to overexpress Ngn3. An ESC line was created that allows for the induction of Ngn3 by adding doxycycline (Dox) to the culture medium. Genome-wide microarray analysis was performed to identify genes regulated by Ngn3 in a variety of both undifferentiated and differentiated conditions. Characterization of pancreatic developmental markers during embryoid body (EB) formation revealed an optimum context for Ngn3 induction. Neuroendocrine genes including neurogenic differentiation 1 (NeuroD1) and single minded 1 (Sim1) were found to be significantly upregulated. Genes regulated by Ngn3 independent of the context were analyzed using systematic gene ontology tools and revealed Notch signaling as the most significantly regulated signaling pathway (p=0.009). This result is consistent with the hypothesis that Ngn3 expression makes the cell competent for Notch signaling to be activated and conversely, more sensitive to Notch signaling inhibition. Indeed, EBs induced to express Ngn3 were significantly more sensitive to gamma-secretase inhibitor-mediated Notch signaling inhibition (p<0.0001). Moreover, we find that Ngn3 induction in differentiating ESCs results in significant increases in insulin, glucagon, and somatostatin transcription.
Differentiation of embryonic stem cells conditionally expressing neurogenin 3.
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View SamplesIn this experiment we compared total RNA from two commonly used choriocarcinoma cell lines, JEG3 and BeWo, to identify differentially expressed transcripts.
Microarray analysis of BeWo and JEG3 trophoblast cell lines: identification of differentially expressed transcripts.
No sample metadata fields
View SamplesTwo T7 based methods One round of Amplification (Affymetrix) and Two round of Amplification were compared to two Ribo-SPIA based systems, RiboSPIA and pico Ribo SPIA systems. Data for Pico-RiboSPIA are listed here.
Microarray-based comparison of three amplification methods for nanogram amounts of total RNA.
No sample metadata fields
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