Investigating neuronal and photoreceptor regeneration in the retina of zebrafish has begun to yield insights into both the cellular and molecular means by which this lower vertebrate is able to repair its central nervous system. However, knowledge about the signaling molecules in the local microenvironment of a retinal injury and the transcriptional events they activate during neuronal death and regeneration is still lacking. To identify genes involved in photoreceptor regeneration, we combined light-induced photoreceptor lesions, laser-capture microdissection (LCM) of the outer nuclear layer (ONL) and analysis of gene expression to characterize transcriptional changes for cells in the ONL as photoreceptors die and are regenerated. Using this approach, we were able to characterize aspects of the molecular signature of injured and dying photoreceptors, cone photoreceptor progenitors and microglia within the ONL. We validated changes in gene expression and characterized the cellular expression for three novel, extracellular signaling molecules that we hypothesize are involved in regulating regenerative events in the retina.
Identification of the molecular signatures integral to regenerating photoreceptors in the retina of the zebra fish.
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View SamplesIn the retina of adult teleosts, stem cells are sustained in two specialized niches: the ciliary marginal zone (CMZ) and the microenvironment surrounding adult Mller glia. Recently, Mller glia were identified as the regenerative stem cells in the teleost retina. Secreted signaling molecules that regulate neuronal regeneration in the retina are largely unknown. In a microarray screen to discover such factors, we identified midkine-b (mdkb). Midkine is a highly conserved heparin-binding growth factor with numerous biological functions. The zebrafish genome encodes two distinct midkine genes: mdka and mdkb. Here, we describe the cellular expression of mdka and mdkb during retinal development and the initial, proliferative phase of photoreceptor regeneration. The results show that in the embryonic and larval retina mdka and mdkb are expressed in stem cells, retinal progenitors and neurons in distinct patterns that suggest different functions for the two molecules. Following the selective death of photoreceptors in the adult, mdka and mdkb are co-expressed in horizontal cells and proliferating Mller glia and their neurogenic progeny. These data reveal that Mdka and Mdkb are signaling factors present in the retinal stem cell niches in both embryonic and mature retinas, and that their cellular expression is actively modulated during retinal development and regeneration.
Cellular expression of midkine-a and midkine-b during retinal development and photoreceptor regeneration in zebrafish.
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View SamplesIDH1-R132H is expressed in Low Grade Glioma (LGG) in combination with loss of function mutation in ATRX and TP53 genes. IDH1-R132H results in gain of function with production of 2-hydroxygluatrate, that in turn generates a hypermethylatyed phenotype in DNA and histone with consequences in epigenetic regulation of gene expression. Here we will compare the gene expression profile between IDH1-R132H and IDH1 Wt LLG animal brain tumors in reponse to radiation Overall design: Evaluate differential gene expression between Brain DH1-R132H and IDH1 wt in response to 10Gy ionizing radiation at 14 days after tumor neurospheres implantation
IDH1-R132H acts as a tumor suppressor in glioma via epigenetic up-regulation of the DNA damage response.
Specimen part, Treatment, Subject
View SamplesBACKGROUND. Perineural invasion (PNI) is the dominant pathway for local invasion in prostate cancer. To date, only few studies have investigated the molecular differences between prostate tumors with PNI and those without it.
Expression of microRNAs and protein-coding genes associated with perineural invasion in prostate cancer.
Race
View SamplesWe show that numerous miRNAs are transcriptionally up-regulated in papillary thyroid carcinoma (PTC) tumors compared with unaffected thyroid tissue. Among the predicted target genes of the three most upregulated miRNAs (miRs 221, 222 and 146b), only less than 15% showed significant downexpression in transcript level between tumor and unaffected tissue. The KIT gene which is known to be downregulated by miRNAs 221 and 222 displayed dramatic loss of transcript and protein in those tumors that had abundant mir-221, mir-222, and mir-146b transcript.
The role of microRNA genes in papillary thyroid carcinoma.
Specimen part
View SamplesMicroRNAs (miRNAs) are small non-protein-coding RNAs that are incorporated into the RNA-induced silencing complex (RISC) and inhibit gene expression by regulating the stability and/or the translational efficiency of target mRNAs. Previously, we demonstrated that miR-210 is a key player of endothelial cell (EC) response to hypoxia, modulating EC survival, migration and ability to form capillary like-structures. Moreover, the receptor tyrosine kinase ligand Ephrin-A3 was identified as one functionally relevant target. Since each miRNA regulates hundreds of mRNAs, different approaches were combined to identify new miR-210 targets: a Using target prediction software, 32 new miR-210 potential targets were identified. b The proteomic profiling of miR-210 over-expressing ECs identified 11 proteins that were specifically inhibited by miR-210, either directly or indirectly. c Affymetrix based gene expression profiles identified 51 genes that were both down-modulated by miR-210 over-expression and de-repressed when miR-210 was blocked. Surprisingly, only few genes identified either by proteomics or transcriptomics were recognized as miR-210 targets by target prediction algorithms. However, a low-stringency pairing research revealed enrichment for miR-210 putative binding sites, raising the possibility that these genes were targeted via non-canonical recognition sequences. To clarify this issue, miR-210-loaded RISC was purified by immuno-precipitation along with its mRNA targets. The presence of Ephrin-A3 mRNA in the complex validated this approach. We found that 32 potential targets were indeed enriched in miR-210-loaded RISC, and thus can be considered as genuine miR-210 targets. In keeping with this conclusion, we were able to further validate a sub-set of them by 3UTR-reporter assays. Gene ontology analysis of the targets confirmed the known miR-210 activity in differentiation and cell cycle regulation, highlighting new functions such as involvement in RNA processing, DNA binding, development, membrane trafficking and amino acid catabolism. In conclusion, we validated a multidisciplinary approach for miRNAs target identification and indicated novel molecular mechanisms underpinning miR-210 role in EC response to hypoxia.
An integrated approach for experimental target identification of hypoxia-induced miR-210.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Cancer exosomes perform cell-independent microRNA biogenesis and promote tumorigenesis.
Specimen part, Cell line
View SamplesThe cancer-risk associated rs6983267 single nucleotide polymorphism (SNP) and the accompanying long non-coding RNA CCAT2 in the highly amplified 8q24.21 region has been implicated in cancer predisposition, though causality has not been established. Here, using allele-specific CCAT2 transgenic mice, we demonstrate that CCAT2 overexpression leads to spontaneous myeloid malignancies. CCAT2 is overexpressed in bone marrow and peripheral blood of myelodysplastic/myeloproliferative neoplasms (MDS/MPN) patients. CCAT2 induces global deregulation of gene expression by downregulating EZH2 in vitro and in vivo in an allele-specific manner. We also identified a novel disease-specific RNA mutation (named DNA-to-RNA allelic imbalance, DRAI) at the SNP locus in MDS/MPN patients and CCAT2-transgenic mice. The RNA transcribed from the SNP locus in malignant hematopoietic cells have different allelic composition from the corresponding genomic DNA, a phenomenon rarely observed in normal cells. Our findings provide fundamental insights into the functional role of rs6983267 SNP and CCAT2 in myeloid malignancies.
Cancer-associated rs6983267 SNP and its accompanying long noncoding RNA <i>CCAT2</i> induce myeloid malignancies via unique SNP-specific RNA mutations.
Specimen part
View SamplesDetermine the effect of miR-203 expression on the global mRNA expression in mesenchymal breast cancer cell line.
Epigenetic silencing of microRNA-203 is required for EMT and cancer stem cell properties.
Specimen part, Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The effects of EBV transformation on gene expression levels and methylation profiles.
Sex, Specimen part, Subject
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