The telomerase RNA component (TERC) is a critical determinant of cellular self renewal. Poly(A)-specific ribonuclease (PARN) is required for post-transcriptional maturation of TERC. PARN mutations lead to incomplete 3' end processing and increased destruction of nascent TERC RNA transcripts, resulting in telomerase deficiency and telomere diseases. Here, we determined that overexpression of TERC increased telomere length in PARN-deficient cells and hypothesized that decreasing post-transcriptional 3' oligo-adenylation of TERC would counteract the deleterious effects of PARN mutations. Inhibition of the noncanonical poly(A) polymerase PAP-associated domain–containing 5 (PAPD5) increased TERC levels in PARN-mutant patient cells. PAPD5 inhibition was also associated with increases in TERC stability, telomerase activity, and telomere elongation. Our results demonstrate that manipulating post-transcriptional regulatory pathways may be a potential strategy to reverse the molecular hallmarks of telomere disease. Overall design: mRNA sequencing of induced pluripotent stem cells and 293 cell line.
Posttranscriptional manipulation of TERC reverses molecular hallmarks of telomere disease.
Specimen part, Subject
View SamplesCockayne syndrome (CS) is an autossomal human disorder characterized by premature aging along with other symptoms. At the molecular level, CS is characterized by a deficiency in the Transcription-couple DNA repair pathway caused by a mutation mainly in ERCC6 gene and the absence of its functional protein. It has been shown that the presence of DNA damage and the lack of some functional proteins related to DNA repair constitute a barrier for somatic cell reprogramming. Recently, it was demonstrated that one protein involved in Genome Global Repair controls the expression of an important pluripotent gene, highligting its importance for cellular reprogramming.
Evidence for premature aging due to oxidative stress in iPSCs from Cockayne syndrome.
Specimen part, Disease, Cell line
View SamplesTransient expression of two factors, or from Oct4 alone, resulted in efficient generation of human iPSCs. The reprogramming strategy described revealed a potential transcriptional signature for human iPSCs yet retaining the gene expression of donor cells in human reprogrammed cells free of viral and transgene interference.
Transcriptional signature and memory retention of human-induced pluripotent stem cells.
Sex, Specimen part
View SamplesStem cells are a potential key strategy for treating neurodegenerative diseases in which the generation of new neurons is critical. A better understanding of the characteristics and molecular properties of neural stem cells (NSC) and differentiated neurons can help in assessing neuronal maturity and possibly in devising better therapeutic strategies. We have therefore performed an in-depth gene expression profiling study of the C17.2 NSC line and primary neurons (PN) derived from embryonic mouse brains. Microarray analysis revealed a neuron-specific gene expression signature that distinguishes PN from NSCs, with elevated levels of transcripts involved in neuronal functions such as neurite development, axon guidance, in PN. The same comparison revealed decreased levels of multiple cytokine transcripts such as IFN, TNF, TGF, and IL. Among the differentially expressed genes, we found a statistically significant enrichment of genes in the ephrin, neurotrophin, CDK5 and actin pathways which control multiple neuronal-specific functions. Furthermore, genes involved in cell cycle were among the most significantly changed in PN. In order to better understand the role of cell cycle arrest in mediating NSCs differentiation, we blocked the cell cycle of NSCs with Mitomycin C (MMC) and examined cellular morphology and gene expression signatures. Although these MMC-treated NSCs displayed a neuronal morphology and expressed some neuronal differentiation marker genes, their gene expression patterns was very different from primary neurons. We conclude that: 1) Fully differentiated primary neurons display a specific neuronal gene expression signature; 2) cell-cycle block in NSC does not induce the formation of fully differentiated neurons; 3) Cytokines such as IFN, TNF, TGF and IL are part of normal NSC function and/or physiology; 4) Signaling pathways of ephrin, neurotrophin, CDK5 and actin, related to major neuronal features, are dynamically enriched in genes showing changes in expression level.
Identification of a neuronal gene expression signature: role of cell cycle arrest in murine neuronal differentiation in vitro.
Sex, Specimen part, Cell line
View SamplesL1 retrotransposons are active elements in the genome, capable of mobilization in neuronal progenitor cells. Previously, we showed that chromatin remodeling during neuronal differentiation allows for a transient stimulation of L1 transcription. The activity of L1 retrotransposons during brain development can impact gene expression and neuronal function. Here we show that L1 neuronal retrotransposition in rodents is increased in the absence of MeCP2, a protein involved in global methylation and human neurodevelopmental diseases. Using neuronal progenitor cells derived from human induced pluripotent stem cells and human tissues, we revealed that Rett syndrome patients, with MeCP2 mutations, have increased susceptibility for L1 retrotransposition. Our data demonstrate that disease-related genetic mutations can influence the frequency of neuronal L1 retrotransposition, thereby increasing brain-specific genetic mosaicism.
A model for neural development and treatment of Rett syndrome using human induced pluripotent stem cells.
Sex, Specimen part, Subject
View SamplesWe generated iPS cells with a synthetic self-replicative RNA that expresses four independent reprogramming factors (OCT4, KLF4, SOX2 and either c-MYC or GLIS1). We performed whole genome RNA sequencing (RNA-seq) of iPS cell clones, parental BJ and HUES9 ES cell controls. All iPS cell clones analyzed by RNA-seq showed unsupervised hierarchical clustering and expression signatures characteristic of human HUES9 ES cells that were highly divergent from parental human fibroblasts. Overall design: RNA-seq in two OKS-iM iPS clones (generated from OCT4, KLF4, SOX2 and cMYC expressing RNA replicon), two OKS-iG clones (generated from OCT4, KLF4, SOX2 and GLIS1 expressing RNA replicon), HUES9 and BJ cells.
Efficient generation of human iPSCs by a synthetic self-replicative RNA.
Specimen part, Subject
View Samples[1] Lactic acidosis time course: MCF7 cells were exposed to lactic acidosis for different length of time. We used microarrays to examine the genomic programs of cells incubated under lactic acidosis for different length of time
Lactic acidosis triggers starvation response with paradoxical induction of TXNIP through MondoA.
Cell line, Treatment
View SamplesThe following abstract from the submitted manuscript describes the major findings of this work.
A role for peroxisome proliferator-activated receptor γ coactivator-1 in the control of mitochondrial dynamics during postnatal cardiac growth.
Specimen part
View SamplesSkeletal muscle adapts to exercise training of various modes, intensities and durations with a programmed gene expression response. This study dissects the independent and combined effects of exercise mode, intensity and duration to identify which exercise has the most positive effects on skeletal muscle health. Full details on exercise groups can be found in: Kraus et al Med Sci Sports Exerc. 2001 Oct;33(10):1774-84 and Bateman et al Am J Cardiol. 2011 Sep 15;108(6):838-44.
Metabolite signatures of exercise training in human skeletal muscle relate to mitochondrial remodelling and cardiometabolic fitness.
Sex, Age, Specimen part, Race, Subject
View SamplesPGC-1 transcription factor was customized to limit its interations to ERRalpha. This mutant (2x9) was used to dissect the transcription activation patterns that are attributable to the PGC1-ERR interaction and PGC-1 actions that are independent of ERR. Inactive mutant with the deleted LLXXL motifs (L2L3) and wt PGC-1 were used as negative and positive controls respectively. BGAL-expressing construct was used to control for non-specific effects of adenoviral infection.
Receptor-selective coactivators as tools to define the biology of specific receptor-coactivator pairs.
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