PURPOSE: Hyperoxia is toxic to photoreceptors, and this toxicity may be important in the progress of retinal dystrophies. This microarray study examines gene expression induced in the C57BL/6J mouse retina by hyperoxia over the 14-day period during which photoreceptors first resist, then succumb to, hyperoxia. METHODS: Young adult C57BL/6J mice were exposed to hyperoxia (75% oxygen) for up to 14 days. On day 0 (control), day 3, day 7, and day 14, retinal RNA was extracted and processed on Affymetrix GeneChip Mouse Genome 430 2.0 arrays. Microarray data were analyzed using GCOS Version 1.4 and GeneSpring Version 7.3.1. RESULTS: The overall numbers of hyperoxia-regulated genes increased monotonically with exposure. Within that increase, however, a distinctive temporal pattern was apparent. At 3 days exposure, there was prominent upregulation of genes associated with neuroprotection. By day 14, these early-responsive genes were downregulated, and genes related to cell death were strongly expressed. At day 7, the regulation of these genes was mixed, indicating a possible transition period from stability at day 3 to degeneration at day 14. CONCLUSIONS: Microarray analysis of the response of the retina to prolonged hyperoxia demonstrated a temporal pattern involving early neuroprotection and later cell death, and provided insight into the mechanisms involved in the two phases of response. As hyperoxia is a consistent feature of the late stages of photoreceptor degenerations, understanding the mechanisms of oxygen toxicity may be important therapeutically.
Gene regulation induced in the C57BL/6J mouse retina by hyperoxia: a temporal microarray study.
Specimen part
View SamplesPurpose: In the C57BL/6J mouse retina, hyperoxia-induced degeneration of photoreceptors shows strong regional variation, beginning at a locus ~0.5mm inferior to the optic disc. To identify gene expression differences that might underlie this variability in vulnerability, we have used microarray techniques to describe regional (superior-inferior) variations in gene expression in the retina.
Differential gene expression in mouse retina related to regional differences in vulnerability to hyperoxia.
Specimen part, Treatment
View SamplesAim: To identify the genes and non-coding RNAs (ncRNAs) involved in the neuroprotective actions of a dietary anti-oxidant (saffron) and of photobiomodulation.
Gene and noncoding RNA regulation underlying photoreceptor protection: microarray study of dietary antioxidant saffron and photobiomodulation in rat retina.
Specimen part
View SamplesCells with slow proliferation kinetics that retain the nuclear label over long time periods – the label-retaining cells (LRCs) – represent multipotent stem cells in a number of adult tissues. Since the identity of liver LRCs (LLRCs) had remained elusive we utilized a genetic approach to reveal LLRCs in normal non-injured livers and characterized their regenerative properties in vivo and in culture. We found that LLRCs were located in biliary vessels and participated in the regeneration of biliary but not hepatocyte injury. In culture experiments the sorted LLRCs displayed an enhanced self-renewal capacity but a unipotent biliary differentiation potential. Transcriptome analysis revealed a unique set of tumorigenesis- and nervous system-related genes upregulated in LLRCs when compared to non-LRC cholangiocytes. We conclude that the LLRCs established during the normal morphogenesis of the liver do not represent a multipotent primitive somatic stem cell population but act as unipotent biliary progenitor cells. Overall design: Transcriptome comparison of label-retaining biliary epithelial cells and non-label-retaining biliary epithelial cells (cells with GFP expression were compared to the cells without GFP). Illumina HiSeq 2000 was used to analyze 8 RNA samples from 4 mice.
A label-retaining but unipotent cell population resides in biliary compartment of mammalian liver.
Subject
View SamplesThe expression profiles of 64 neuroblastic tumors (mainly neuroblastoma) were determined on Affymetrix chips HG U133 Plus 2.0.
Somatic and germline activating mutations of the ALK kinase receptor in neuroblastoma.
No sample metadata fields
View SamplesAFN-1252 is an inhibitor of fatty acid biosynthesis. Gene expression profiles were generated by microarray analysis of S. aureus cells following treatment with AFN-1252, an inhibitor of fatty acid synthesis.
Perturbation of Staphylococcus aureus gene expression by the enoyl-acyl carrier protein reductase inhibitor AFN-1252.
No sample metadata fields
View SamplesStabilin-1/CLEVER-1 is a multidomain protein present in lymphatic and vascular endothelial cells and in M2 immunosuppressive macrophages. Stabilin-1 functions in scavenging, endocytosis and leukocyte adhesion to and transmigration through the endothelial cells. Overall design: The transcriptome of liver tissue in 5wk old Stab1 knock-out mice was compared to that of corresponding wild type mice
Stabilin-1 expression defines a subset of macrophages that mediate tissue homeostasis and prevent fibrosis in chronic liver injury.
Age, Specimen part, Subject
View SamplesSir2 is an NAD+-dependent histone deacetylase, and is the founding member of a large, phylogentically conserved, family of such deacetylases called the Sirtuins. The budding yeast, Saccharomyces cerevisiae, harbors 4 paralogs of Sir2, known as Hst1, Hst2, Hst3, and Hst4. Reducing the intracellular NAD+ concentration is inhibitory for the Sirtuins, and raising the intracellular nicotinamide (NAM) concentration is inhibitory. Microarray gene expression analysis was used to identify novel classes of yeast genes whose expression is altered when either NAD+ concentration is reduced or NAM is elevated. A subset of genes involved in thiamine biosynthesis was identified as being upregulated when Sir2 or Hst1 was inactivated.
Thiamine biosynthesis in Saccharomyces cerevisiae is regulated by the NAD+-dependent histone deacetylase Hst1.
No sample metadata fields
View SamplesThe chronological lifespan (CLS) of Saccharomyces cerevisiae is defined as the number days that non-dividing cells remain viable, typically in stationary phase cultures or in water. CLS is extended by restricting glucose in the starting cultures, and is considered a form of caloric restriction (CR). Through a previous genetic screen our lab determined that deleting components of the de novo purine biosynthesis pathway also significantly increased CLS. Significant similarities in gene expression profiles between calorie restricted WT cells and a non-restricted ade4 mutant suggested the possibility of common gene expression biomarkers of all chronologically long lived cells that could also provide insights into general mechanisms of lifespan extension. We have identified additional growth conditions that extend CLS of WT cells, including supplementation of the media with isonicotinamide (INAM), a known sirtuin activator, or by supplementation with a concentrate collected from the expired media of a calorie restricted yeast culture, presumably due to an as yet unidentified longevity factor. Using these varied methods to extend CLS, we compared gene expression profiles in the aging cells (at day 8) to identify functionally relevant biomarkers of longevity. Nineteen genes were differentially regulated in all 4 of the long-lived populations relative to wild type. Of these 19 genes, viable haploid deletion mutants were available for 16 of them, and 12 were found to have a significant impact on CLS.
Functional genomic analysis reveals overlapping and distinct features of chronologically long-lived yeast populations.
No sample metadata fields
View SampleshTERT/cdk4 immortalized myogenic human cell lines represent an important tool for skeletal muscle research, being used as therapeutically-pertinent models of various neuromuscular disorders and in numerous fundamental studies of muscle cell function. However, the cell cycle is linked to other cellular processes such as integrin regulation, the PI3K/Akt pathway, and microtubule stability, raising the question as to whether transgenic modification of the cell cycle results in secondary effects that could undermine the validity of these cell models. Here we subjected healthy and disease lines to intensive transcriptomic analysis, comparing immortalized lines with their parent primary populations in both differentiated and undifferentiated states, and testing their myogenic character by comparison with non-myogenic (CD56-negative) cells. We found that immortalization has no measurable effect on the myogenic cascade or on any other cellular processes, and that it was protective against the systems level effects of senescence that are observed at higher division counts of primary cells.
Skeletal muscle characteristics are preserved in hTERT/cdk4 human myogenic cell lines.
Specimen part, Disease, Disease stage
View Samples