A key event in the pathogenic process of prion diseases is the conversion of the cellular prion protein (PrPC) to an abnormal and protease-resistant isoform (PrPSc). Mice lacking PrP are resistant to prion infection, and down-regulation of PrPC during prion infection prevents neuronal loss and the progression to clinical disease. These results are suggestive of the potential beneficial effect of silencing PrPC during prion diseases. However, the silencing of a protein that is widely expressed throughout the CNS could be detrimental to brain homeostasis. The physiological role of PrPC remains still unclear, but several putative functions have been proposed. Among these, several lines of evidence support PrPC function in neuronal development and maintenance.
Developmental influence of the cellular prion protein on the gene expression profile in mouse hippocampus.
Specimen part
View SamplesBackground:
Natural variants of AtHKT1 enhance Na+ accumulation in two wild populations of Arabidopsis.
Specimen part
View SamplesDownregulation of expression and activity levels of the astroglial glutamate transporter EAAT2 is thought to be implicated in motor neuron excitotoxicity in amyotrophic lateral sclerosis (ALS). We previously reported that EAAT2 is cleaved by caspase-3 at the cytosolic C-terminus domain, impairing the transport activity and generating a proteolytic fragment found to be SUMO1 conjugated (CTE-SUMO1). We show here that this fragment accumulates in the nucleus of spinal cord astrocytes in vivo throughout the disease stages of the SOD1-G93A mouse model of ALS. In vitro expression in spinal cord astrocytes of the C-terminus peptide of EAAT2 (CTE), which was artificially fused to SUMO1 (CTE-SUMO1fus) to mimic the endogenous SUMOylation reaction, recapitulates the nuclear accumulation of the fragment seen in vivo and causes caspase-3 activation and axonal growth impairment in motor neuron-derived NSC-34 cells and primary motor neurons co-cultured with CTE-SUMO1fus-expressing spinal cord astrocytes. This indicates that CTE-SUMO1fus could trigger non-cell autonomous mechanisms of neurodegeneration. Prolonged nuclear accumulation of CTE-SUMO1fus in astrocytes leads to their degeneration, although the time frame of the cell-autonomous toxicity is longer than the one for the indirect toxic effect on motor neurons. As more evidence on the implication of SUMO substrates in neurodegenerative diseases emerges, our observations strongly suggest that the nuclear accumulation in spinal cord astrocytes of a SUMOylated proteolytic fragment of the astroglial glutamate transporter EAAT2 could take part to the pathogenesis of ALS and suggest a novel, unconventional role for EAAT2 in motor neuron degeneration in ALS.
Motor neuron impairment mediated by a sumoylated fragment of the glial glutamate transporter EAAT2.
Specimen part
View SamplesThe regulation of necrotic death and its relevance in anti-cancer therapy are largely unknown. Here we have investigated the pro-apoptotic and pro-necrotic activities of two ubiquitin-proteasome system inhibitors (UPSIs): bortezomib and G5. The present study points out that the glioblastoma cell lines U87MG and T98G are useful models to study the susceptibility to apoptosis and necrosis in response to UPSIs. U87MG cells are resistant to apoptosis induced by bortezomib and G5 but susceptible to necrosis induced by G5. On the opposite T98G cells are susceptible to apoptosis induced by both inhibitors but show some resistance to G5-induced necrosis. By comparing the transcriptional profiles of the two cell lines, we have found that the resistance to G5-induced necrosis could arise from differences in glutathione synthesis/utilization and in the microenvironment. In particular collagen IV, which is highly expressed in T98G cells, and fibronectin, whose adhesive function is counteracted by tenascin-C in U87MG cells, can restrain the necrotic response to G5. Collectively, our results provide an initial characterization of the molecular signals governing cell death by necrosis in glioblastoma cell lines.
Characterization of caspase-dependent and caspase-independent deaths in glioblastoma cells treated with inhibitors of the ubiquitin-proteasome system.
Cell line
View SamplesCXCR4 cDNA transcripts were subcloned into plenti-IRES-GFP vectors, and stably transduced using a lentiviral system In addition to wild-type CXCR4, vectors with the mutations c.1013C>G (p.Ser338*), c.932_933insT (p.Thr311fs), and c.1030_1041delinsGT (p.Ser344fs) were generated.
Transcriptome sequencing reveals a profile that corresponds to genomic variants in Waldenström macroglobulinemia.
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A transcriptome analysis identifies molecular effectors of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells.
Specimen part, Cell line, Treatment
View SamplesThe deposition of unconjugated bilirubin (UCB) in selected regions of the brain results in irreversible neuronal damage, or Bilirubin Encephalopathy (BE). Although UCB impairs a large number of cellular functions, the basic mechanisms of neurotoxicity have not yet been fully clarified. While cells can accumulate UCB by passive diffusion, cell protection may involve multiple mechanisms including the extrusion of the pigment as well as pro-survival homeostatic responses that are still unknown. The effects of UCB treatment to SH-SY5Y neuroblastoma cell line were examined by high density oligonucleotide microarrays. 230 genes were induced after 24 hours. A Gene Ontology (GO) analysis showed that a large group of UCB-induced genes were components of the ER stress response. Independent experimental validation of molecular events crucial for the ER stress response is presented. The results show that UCB exposure induces ER stress response as major intracellular homeostatic response in neuroblastoma cells in vitro. Our finding may provide valuable information for new therapeutic strategies in the treatment of BE.
A transcriptome analysis identifies molecular effectors of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells.
Specimen part
View SamplesThe deposition of unconjugated bilirubin (UCB) in selected regions of the brain results in irreversible neuronal damage, or Bilirubin Encephalopathy (BE). Although UCB impairs a large number of cellular functions, the basic mechanisms of neurotoxicity have not yet been fully clarified. While cells can accumulate UCB by passive diffusion, cell protection may involve multiple mechanisms including the extrusion of the pigment as well as pro-survival homeostatic responses that are still unknown. The effects of UCB treatment to SH-SY5Y neuroblastoma cell line were examined by high-density oligonucleotide microarrays. 230 genes were induced after 24 hours. A Gene Ontology (GO) analysis showed that a large group of UCB-induced genes were components of the ER stress response. Independent experimental validation of molecular events crucial for the ER stress response is presented. The results show that UCB exposure induces the ER stress response as a major intracellular homeostatic response in neuroblastoma cells in vitro. Our finding may provide valuable information for new therapeutic strategies in the treatment of BE.
A transcriptome analysis identifies molecular effectors of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells.
Specimen part, Cell line, Treatment
View SamplesThe deposition of unconjugated bilirubin (UCB) in selected regions of the brain results in irreversible neuronal damage, or Bilirubin Encephalopathy (BE). Although UCB impairs a large number of cellular functions, the basic mechanisms of neurotoxicity have not yet been fully clarified. While cells can accumulate UCB by passive diffusion, cell protection may involve multiple mechanisms including the extrusion of the pigment as well as pro-survival homeostatic responses that are still unknown. The effects of UCB treatment to SH-SY5Y neuroblastoma cell line were examined by high-density oligonucleotide microarrays. 230 genes were induced after 24 hours. A Gene Ontology (GO) analysis showed that a large group of UCB-induced genes were components of the ER stress response. Independent experimental validation of molecular events crucial for the ER stress response is presented. The results show that UCB exposure induces the ER stress response as a major intracellular homeostatic response in neuroblastoma cells in vitro. Our finding may provide valuable information for new therapeutic strategies in the treatment of BE.
A transcriptome analysis identifies molecular effectors of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells.
Specimen part, Cell line, Treatment
View SamplesDJ-1 is an atypical peroxiredoxin-like peroxidase that may act as a redox-dependent chaperone and a regulator of transcription. To explore DJ-1-mediated transcriptional control in Parkinsons disease (PD), we generated human neuroblastoma cells with inducible knock-down of DJ-1 expression. We then used functional genomic techniques to identify novel pathways dysregulated by loss of DJ-1 function. Using microarray gene expression profiling, we found that DJ-1 silencing alters the expression of 26 genes, with 10 down-regulated and 16 up-regulated transcripts. Among the down-regulated genes we found Ret, tyrosine kinase receptor for the neurotrophic factor GDNF. Taking advantage of Ingenuity Pathways Analysis, we identified hypoxia inducible factor 1 alpha (Hif1a) as a possible mediator of the interplay between DJ-1 and Ret. We show that Hif1a is stabilized in the absence of DJ-1, and that loss of DJ-1 generates hypoxia and accumulation of free radical species (ROS). Overexpression of wt DJ-1, but not of C106A and L166P mutants deficient in ROS scavenger activity, rescues Ret expression in neuroblastoma cells. These findings reveal novel players in PD pathogenesis and provide evidence for additional pathways involved in DJ-1-mediated neurodegeneration.
Parkinson disease-associated DJ-1 is required for the expression of the glial cell line-derived neurotrophic factor receptor RET in human neuroblastoma cells.
Specimen part, Cell line
View Samples