Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder that is clinically defined in terms of motor symptoms. These are preceded by prodromal non-motor manifestations that prove the systemic nature of the disease. Identifying genes and pathways altered in living patients provide new information on the diagnosis and pathogenesis of sporadic PD. We study changes in gene expression in the blood of 40 sporadic PD patients and 20 healthy controls (Discovery set) by taking advantage of the Affymetrix platform. Patients were at the onset of motor symptoms and before initiating any pharmacological treatment. By applying Ranking-Principal Component Analysis, PUMA and Significance Analysis of Microarrays, gene expression profiling discriminates patients from healthy controls and identifies differentially expressed genes in blood. The majority of these are also present in dopaminergic neurons of the Substantia Nigra, the key site of neurodegeneration. Together with neuronal apoptosis, lymphocyte activation and mitochondrial dysfunction, already found in previous analysis of PD blood and post-mortem brains, we unveiled transcriptome changes enriched in biological terms related to epigenetic modifications including chromatin remodeling and methylation. Candidate transcripts were validated by RT-qPCR in an independent cohort of 12 patients and controls (Validation set). Our data support the use of blood transcriptomics to study neurodegenerative diseases. It identifies changes in crucial components of chromatin remodeling and methylation machineries as early events in sporadic PD suggesting epigenetics as target for therapeutic intervention.
Blood transcriptomics of drug-naïve sporadic Parkinson's disease patients.
Specimen part, Disease
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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 SamplesA 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 SamplesDiamond-Blackfan Anemia (DBA) is a rare inherited red cell hypoplasia characterized by a defect in the maturation of erythroid progenitors and is in some cases associated to malformations. Patients have an increased risk of solid tumors. Mutations have been found in several ribosomal protein (RP) genes. Studies in hematopoietic progenitors from patients show that the haploinsufficiency of an RP impairs rRNA processing and ribosome biogenesis. DBA lymphocytes and fibroblasts show reduced protein synthesis, and the latter display abnormal rRNA processing and impaired proliferation.
Fibroblasts from patients with Diamond-Blackfan anaemia show abnormal expression of genes involved in protein synthesis, amino acid metabolism and cancer.
Sex, Disease, Disease stage
View SamplesTo identify altered pathways in SCA28 LCLs, we performed a whole genome expression profiling, based on Affymetrix Human Genome U133A 2.0 Chip Array, on LCLs from four unrelated patients, each carrying a different AFG3L2 mutation.
Genome-wide expression profiling and functional characterization of SCA28 lymphoblastoid cell lines reveal impairment in cell growth and activation of apoptotic pathways.
Sex, Specimen part
View SamplesMurine ES-derived neural stem cells (NSC) were not irradiated (ctrl) or irradiated with 10Gy and cultured for 7 days (irr).
DNA damage in mammalian neural stem cells leads to astrocytic differentiation mediated by BMP2 signaling through JAK-STAT.
Specimen part
View SamplesLineage-specific transcription factors, which drive cellular identity during embryogenesis, have been shown to convert cell fate when express ectopically in heterologous cells. Herein, we screened the key molecular factors governing the dopaminergic neuronal specification during brain development for their ability to generate similar neurons directly from mouse and human fibroblasts. Remarkably, we found a minimal set of three factors Mash1, Nurr1 and Lmx1a/b able to elicit such cellular reprogramming. Molecular and transcriptome studies showed reprogrammed DA neurons to faithfully recapitulate gene expression of their brain homolog cells while lacking expression of other catecholaminergic neuronal types. Induced neurons showed spontaneous electrical activity organized in regular spikes consistent with the pacemaker activity featured by brain DA neurons. The three factors were able to elicit DA neuronal conversion in human fibroblasts from prenatal or adult fibroblasts of healthy donors and a Parkinsons disease patient. Generation of DA induced neurons from somatic cells might have significant implications in studies of neural development, disease in vitro modeling and cell replacement therapies.
Direct generation of functional dopaminergic neurons from mouse and human fibroblasts.
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 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 SamplesThe mesencephalic dopaminergic (mDA) cell system is composed by two major groups of projecting cells in the Substantia Nigra (A9 neurons) and the Ventral Tegmental Area (A10 cells). A9 neurons form the nigrostriatal pathway and are involved in regulating voluntary movements and postural reflexes. Their selective degeneration leads to Parkinsons disease (PD). We used cDNA microarrays and nanoCAGE technology coupled with Laser Capture Microdissection (LCM) to characterize the intrinsic physiological properties of A9 DA neurons. Surprisingly, we found that these cells express alpha- and beta- chains of haemoglobin. Here we report that globin-immunoreactivity decorates the majority of A9 DA neurons, a subpopulation of cortical and hippocampal astrocytes as well as mature oligodendrocytes. This pattern of expression was confirmed in different mouse strains, in rat and human. This is the first report showing that haemoglobin is expressed in the Substantia Nigra of human post mortem brain. Our data suggest that the most famed oxygen-carrying globin is not exclusively restricted to the blood, but it may play a role in the normal physiology of the brain as well as in neurodegenerative disorders.
Unexpected expression of alpha- and beta-globin in mesencephalic dopaminergic neurons and glial cells.
Cell line
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