Purpose: Investigate the molecular determinants of retinal regeneration in adult vertebrates by analyzing the gene expression profiles of control and post-lesion retina of adult zebrafish, a system that regenerates following injury.
Gene expression profiles of intact and regenerating zebrafish retina.
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View SamplesLow-oxygen tolerance is supported by an adaptive response that includes a coordinate shift in metabolism and the activation of a transcriptional program that is driven by the hypoxia-inducible factor (HIF) pathway. The precise contribution of HIF-1 in the adaptive response, however, has not been determined. Here we investigate how HIF-1 influences hypoxic adaptation throughout Drosophila development. We find that hypoxic-induced transcriptional changes are comprised of HIF-dependent and HIF-independent pathways that are distinct and separable. We show that normoxic set-points of carbohydrate metabolites are significantly altered in dHIF mutants and that these animals are unable to mobilize glycogen in hypoxia. Furthermore, we find that the estrogen-related receptor (dERR), which is a global regulator of aerobic glycolysis in larvae, is required for a competent hypoxic response. dERR binds to dHIF and participates in the HIF-dependent transcriptional program in hypoxia. In addition, dERR acts in the absence of dHIF in hypoxia and a significant portion of HIF-independent transcriptional responses can be attributed to dERR actions, including upregulation of glycolytic transcripts. These results indicate that competent hypoxic responses arise from complex interactions between HIF-dependent and -independent mechanisms, and that dERR plays a central role in both of these programs.
HIF- and non-HIF-regulated hypoxic responses require the estrogen-related receptor in Drosophila melanogaster.
Specimen part
View SamplesMethods: RNA-seq libraries were prepared using the Illumina TruSeq technology. The libraries were quantified and samples were multiplexed in each lane of the flowcell. Cluster generation was performed and then sequenced on the Illumina HiSeq2500 system. Reads were mapped on the Human Genome Reference (GRCh38) and normalized expression table was generated. Results: Among differentially expressed genes, compared with DMSO-treated hiPSC-CMs, 505 genes were upregulated in FM+WY+TID-treated hiPSC-CMs, with 72 genes commonly upregulated in both FM+WY+TID-treated hiPSC-CMs and LV groups and 949 genes were downregulated in FM+WY+TID-treated hiPSC-CMs and 2137 genes were downregulated in LV, with 437 genes downregulated in both FM+WY+TID-treated hiPSC-CMs and LV compared with DMSO-treated hiPSC-CMs . Conclusions: Data demonstrate increased expression of genes associated with many metabolic processes which are also highly enriched in human pediatric heart samples including many interconnected metabolic processes that are upstream of lipid metabolism and FAO, agreeing with the shift to FAO for energy utilization in more mature CMs, and decreased expression of genes involved in developmental processes, adhesion and signaling in both FM+WY+TID-treated hiPSC-CMs and LV. The overlap in both upregulated and downregulated genes in both groups confirmed an advanced degree of cardiomyocyte maturation in response to FM+WY+TID. Overall design: RNA-sequencing analysis was performed to compare global gene expression profiles of hiPSC-CMs at differentiation day 28 with maturation factors (FM+WY+TID) treatment (Treat) vs. DMSO treatment (DMSO) vs. left ventricle tissue sample (LV).
Targeting HIF-1α in combination with PPARα activation and postnatal factors promotes the metabolic maturation of human induced pluripotent stem cell-derived cardiomyocytes.
Specimen part, Subject
View SamplesThe neuronal ceroid lipofuscinoses (NCL) are a group of childhood inherited neurodegenerative disorders characterized by blindness, early dementia and pronounced cortical atrophy. The similar pathological and clinical profiles of different forms of NCL suggest that common disease mechanisms may be involved. Here, we have performed quantitative gene expression profiling of cortex from targeted knock out mice produced for Cln1 and Cln5 to explore NCL-associated molecular pathways. Combined microarray datasets from both mouse models exposed a common affected pathway: genes regulating cytoskeletal dynamics and neuronal growth cone stabilization display similar aberrations. We analyzed locus specific gene expression and showed regional clustering of Cln1 and three major genes of this pathway, further supporting a close functional relationship between the corresponding gene products, Cap1, Ptprf and Ptp4a2. The evidence from the gene expression data was substantiated by immunohistochemical staining data of Cln1-/- and Cln5-/- cortical neurons. These primary neurons displayed abnormalities in beta-tubulin and actin as well as abnormal intracellular distribution of growth cone associated proteins GAP-43, synapsin and Rab3. Our data provide the first evidence for a common molecular pathogenesis behind neuronal degeneration in CLN1 and CLN5. Since CLN1 and CLN5 code for proteins with distinct functional roles these data may have implications for other forms of NCL.
Brain gene expression profiles of Cln1 and Cln5 deficient mice unravels common molecular pathways underlying neuronal degeneration in NCL diseases.
Sex, Age, Specimen part, Disease
View SamplesReprogramming of somatic cells is a valuable tool to understand the mechanisms of regaining pluripotency and further opens up the possibility of generating patient-specific pluripotent stem cells. Reprogramming of mouse and human somatic cells into pluripotent stem cells, designated as induced pluripotent stem (iPS) cells, has been possible with the expression of the transcription factor quartet Oct4 (also known as Pou5f1), Sox2, c-Myc, and Klf4. Considering that ectopic expression of c-Myc causes tumourigenicity in offspring and retroviruses themselves can cause insertional mutagenesis, the generation of iPS cells with a minimal number of factors may hasten the clinical application of this approach. Here, we show that adult mouse neural stem cells express higher endogenous levels of Sox2 and c-Myc than embryonic stem cells, and that exogenous Oct4 together with either Klf4 or c-Myc are sufficient to generate iPS cells from neural stem cells. These two-factor (2F) iPS cells are similar to embryonic stem cells at the molecular level, contribute to development of the germ line, and form chimeras. We propose that, in inducing pluripotency, the number of reprogramming factors can be reduced when using somatic cells that endogenously express appropriate levels of complementing factors.
Pluripotent stem cells induced from adult neural stem cells by reprogramming with two factors.
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View SamplesTopoisomerase 1 (TOP1) poisons like camptothecin (CPT), which are used as chemotherapeutic agents in cancer, elicit DNA damage in quiescient neurons. In this study, we examined the effects of CPT and actinomycin D (ActD) on neuronal cells. Motor (MNs) and cortical (CNs) neurons were more susceptible to the toxic effects of CPT and ActD than fibroblasts. MNs and CNs exhibited a delayed DNA damage responseincrease in nuclear -H2AX focirelative to fibroblasts. Neuronal cells expressed higher levels of Top1 mRNA than fibroblasts which could explain their enhanced vulnerability to CPT and ActD toxicity. Microarray analysis was performed to identify differentially regulated transcripts in MNs treated with CPT for 2 hours. Many immediate-early genes including Fos and Egr-1 were upregulated in CPT-treated MNs. Fos mRNA levels were elevated in all cells types treated with CPT; Egr-1 transcript levels, however, were reduced in CPT-treated fibroblasts even though they were elevated in treated MNs and CNs. Pathway and network analysis of the differentially expressed transcripts revealed activation of ERK and JNK signaling cascades in CPT-treated MNs. In conclusion, MNs were more vulnerable than fibroblasts to the damaging effects of TOP1 poisons and they elicit a unique intracellular response to CPT treatment.
Identification of early gene expression changes in primary cultured neurons treated with topoisomerase I poisons.
Specimen part, Treatment
View SamplesIn this analysis we have compared the gene expression profiles of lymphatic endothelial cells (LECs) isolated from human intestine (iLECs) versus LECs from human skin (dLECs).
Liprin (beta)1 is highly expressed in lymphatic vasculature and is important for lymphatic vessel integrity.
Specimen part
View SamplesExpression of germ cell nuclear factor (GCNF, Nr6a1), an orphan member of the nuclear receptor gene family of transcription factors, during gastrulation and neurulation is critical for normal embryogenesis in mice. Gcnf represses the expression of the POU domain transcription factor Oct4 (Pou5f1) during mouse post-implantation development. Although Gcnf expression is not critical for the embryonic segregation of the germ cell lineage, we found that sexually dimorphic expression of Gcnf in germ cells correlates with the expression of pluripotency-associated genes, such as Oct4, Sox2, and Nanog, as well as the early meiotic marker gene Stra8. To elucidate the role of Gcnf during mouse germ cell differentiation, we generated an ex vivo Gcnf-knockdown model in combination with a regulated CreLox mutation of Gcnf. Lack of Gcnf impairs normal spermatogenesis and oogenesis in vivo, as well as the derivation of germ cells from embryonic stem cells (ESCs) in vitro. Inactivation of the Gcnf gene in vivo leads to loss of repression of Oct4 expression in both male and female gonads.
Germ cell nuclear factor regulates gametogenesis in developing gonads.
Specimen part
View SamplesConrad et al. Nature 456, 344349 (2008) have generated human adult germline stem cells (haGSCs) from human testicular tissue, which they claim have similar pluripotent properties to human embryonic stem cells (hESCs). Here we investigate the pluripotency of haGSCs by using global gene-expression analysis based on their gene array data and comparing the expression of pluripotency marker genes in haGSCs and hESCs, and in haGSCs and human fibroblast samples derived from different laboratories, including our own. We find that haGSCs and fibroblasts have a similar gene-expression profile, but that haGSCs and hESCs do not. The pluripotency of Conrad and colleagues haGSCs is therefore called into question.
Human adult germline stem cells in question.
Specimen part
View SamplesOld C57BL/6 mice cannot mount an effective innate immune response
Aged mice are unable to mount an effective myeloid response to sepsis.
Specimen part, Treatment, Time
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