Leptin binding to the leptin receptor (LepR) causes rapid signaling to the nucleus. We investigated the early (2 hr) transcriptional response to acute leptin injection (intracerebroventricular)
Leptin Induces Mitosis and Activates the Canonical Wnt/β-Catenin Signaling Pathway in Neurogenic Regions of <i>Xenopus</i> Tadpole Brain.
Treatment
View SamplesPurpose: Zebrafish neurons regenerate from Müller glia following retinal lesions. Genes and signaling pathways important for retinal regeneration in zebrafish have been described, but our understanding of how Mu¨ller glial stem cell properties are regulated is incomplete. Mammalian Mu¨ller glia possess a latent neurogenic capacity that might be enhanced in regenerative therapies to treat degenerative retinal diseases. Methods: To identify transcriptional changes associated with stem cell properties in zebrafish Mu¨ller glia, we performed a comparative transcriptome analysis from isolated cells at 8 and 16 hours following an acute, photic lesion, prior to the asymmetric division that produces retinal progenitors. Results: We report a rapid, dynamic response of zebrafish Müller glia, characterized by activation of pathways related to stress, NF-kappa B signaling, cytokine signaling, immunity, prostaglandin metabolism, circadian rhythm, and pluripotency, and an initial repression of Wnt signaling. When we compared publicly available transcriptomes of isolated mouse Mu¨ller glia from two retinal degeneration models, we found that mouse Müller glia showed evidence of oxidative stress, variable responses associated with immune regulation, and repression of pathways associated with pluripotency, development, and proliferation. Conclusions: Categories of biological processes/pathways activated following photoreceptor loss in regeneration-competent zebrafish Mu¨ller glia, which distinguished them from mouse Mu¨ller glia in retinal degeneration models, included: cytokine signaling (notably NF-kappa B), prostaglandin E2 synthesis, expression of core clock genes, and pathways/metabolic states associated with pluripotency. These regulatory mechanisms are relatively unexplored as potential mediators of stem cell properties likely to be important in Müller glial cells for successful retinal regeneration. Overall design: Transcriptional profiles of 0, 8, and 16 hour post-lesion zebrafish Müller glia (in triplicate) were generated by high-throughput sequencing in an Illumina GAIIx.
Rapid, Dynamic Activation of Müller Glial Stem Cell Responses in Zebrafish.
No sample metadata fields
View SamplesHigher order chromosome structure and nuclear architecture can have profound effects on gene regulation. We analyzed how compartmentalizing the genome by tethering heterochromatic regions to the nuclear lamina affects dosage compensation in the nematode C. elegans. In this organism, the dosage compensation complex (DCC) binds both X chromosomes of hermaphrodites to repress transcription two-fold, thus balancing gene expression between XX hermaphrodites and XO males. X chromosome structure is disrupted by mutations in DCC subunits. Using X chromosome paint fluorescence microscopy, we found that X chromosome structure and subnuclear localization are also disrupted when the mechanisms that anchor heterochromatin to the nuclear lamina are defective. Strikingly, the heterochromatic left end of the X chromosome is less affected than the gene-rich middle region, which lacks heterochromatic anchors. These changes in X chromosome structure and subnuclear localization are accompanied by small, but significant levels of derepression of X-linked genes as measured by RNA-seq, without any observable defects in DCC localization and DCC-mediated changes in histone modifications. We propose a model in which heterochromatic tethers on the left arm of the X cooperate with the DCC to compact and peripherally relocate the X chromosomes, contributing to gene repression. Overall design: RNA-seq profiles of C. elegans L1 wild type hermaphrodites, cec-4, met-2 set-25, and DPY-27 RNAi. RNA-seq profiles or C. elegans. Strains are N2 Bristol strain (wild type), RB2301 cec-4(ok3124) IV, and EKM99 met-2(n4256) set-25(n5021) III. Biological replicates for each strain/stage listed separately.
Anchoring of Heterochromatin to the Nuclear Lamina Reinforces Dosage Compensation-Mediated Gene Repression.
Specimen part, Subject
View SamplesThe goal of this study is to analyzed transcriptome changes caused by POLA1 deficiency. Our data represents the first detailed analysis of molecular basis of XLPDR syndrome. We report than POLA1 deficiency leads to over-activation of IRF and NF-kB pathways with overexpression of typical markers of autoimmune syndromes. Overall design: Wild type and XLPDR-derived dermal fibroblasts are analyzed under non-stimulated (basal) conditions, after TNF treatment (2 and 12 h, 1000 U/mL), and poly(dA:dT) stimulation (16h, 1 mkg/mL). Obtained data were confirmed using the cellular model of XLPDR - normal dermal fibroblasts pretreated with control or anti-POLA1 siRNA and stimulated in analogous way.
NK cell defects in X-linked pigmentary reticulate disorder.
No sample metadata fields
View SamplesThe Microarray study was designed to characterize the whole genome transcription profile of two subpopulations of H1 human embryonic stem cells we identified by size using flow cytometry.The heterogeneous nature of stem cells is an important issue in both research and therapeutic use in terms of directing cell lineage differentiation pathways, as well as self-renewal properties. Using flow cytometry we have identified two distinct subpopulations by size within the H1 and BGN1 human embryonic stem (hES) cell lines. Both populations express stem the cell markers Oct-4, Nanog, Tra-1-60, Tra-1-80 and SSea-4 and express very low levels of differentiation markers common to the three germ layers. To investigate if the two populations possessed different transcription profiles, we performed whole genome microarray analysis, and identified approximately 400 genes with significant differential expression (p<0.01). Cloning experiments indicate that both populations are able to repopulate each other and maintain the parental population. The large cell population responds to retinoic acid (RA) differentiation as evidenced by greater than a 50% loss of gated cell number and loss of Oct-4 expression; while the small cell population number does not change and maintains Oct-4 protein expression. The presence of these two populations could be vitally important with respect to stem cell therapy and research as they respond differently to differentiation signals, which may be important in directing stem cell differentiation for disease therapy.
Differential responses to retinoic acid and endocrine disruptor compounds of subpopulations within human embryonic stem cell lines.
Specimen part, Disease, Cell line
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