Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Nrf2-related oxidative stress response and impaired dopamine biosynthesis in a PC12 cell model of Huntingtonâs disease

ABSTRACT: Huntingtonâs disease (HD) is a devastating disease for which currently no therapy is available. It is a progressive autosomal dominant neurodegenerative disorder that is caused by a CAG repeat expansion in the HD gene, resulting in an expansion of polyglutamines at the N-terminal end of the encoded protein, designated huntingtin, and the accumulation of cytoplasmic and nuclear aggregates. Not only is there a loss of normal huntingtin function, upon expansion of the CAG repeat there is also a gain of toxic function of the huntingtin protein and this affects a wide range of cellular processes. To identify groups of genes that could play a role in the pathology of Huntingtonâs disease, we studied mRNA changes in an inducible PC12 model of Huntingtonâs disease before and after aggregates became visible. This is the first study to show the involvement Nrf2-responsive genes in the oxidative stress response in HD. Oxidative stress related transcripts were altered in expression suggesting a protective response in cells expressing mutant huntingtin at an early stage of cellular pathology. Furthermore, there was a down-regulation of catecholamine biosynthesis resulting in lower dopamine levels in culture. Our results further demonstrate an early impairment of transcription, the cytoskeleton, ion channels and receptors. Given the pathogenic impact of oxidative stress and neuroinflammation, the Nrf2-ARE signaling pathway is an attractive therapeutic target for neurodegenerative diseases. Keywords: Gene expression analysis, Huntington's disease, oxidative stress, PC12 cell model For each construct, we performed duplicate experiments with 2 independent cell lines for each construct yielding 2 biological replicates. Furthermore, from each cell line, two separate RNA isolations were performed serving as technical replicates. For PC12 cells with no construct, only a technical replicate was used. RNA was harvested prior to induction (day 0), after 24 hours of induction (day 1) and after 5 days of induction of exon 1 huntingtin fragments with normal (Q23) and extended (Q74) glutamine repeat length.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Peter 't Hoen

PROVIDER: E-GEOD-10581 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Mutant huntingtin activates Nrf2-responsive genes and impairs dopamine synthesis in a PC12 model of Huntington's disease.

van Roon-Mom Willeke M C WM Pepers Barry A BA 't Hoen Peter A C PA Verwijmeren Carola A C M CA den Dunnen Johan T JT Dorsman Josephine C JC van Ommen Gertjan B GB

BMC molecular biology 20081009

<h4>Background</h4>Huntington's disease is a progressive autosomal dominant neurodegenerative disorder that is caused by a CAG repeat expansion in the HD or Huntington's disease gene. Although micro array studies on patient and animal tissue provide valuable information, the primary effect of mutant huntingtin will inevitably be masked by secondary processes in advanced stages of the disease. Thus, cell models are instrumental to study early, direct effects of mutant huntingtin. mRNA changes wer ...[more]

PMID: 18844975

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Project description:HuntingtonÂs disease (HD) is a devastating neurodegenerative disease, with out effective treatment. Despite significant advances, our understanding of how an expanded CAG repeat in the amino terminus of the large ubiquitously expressed HD gene product remains incomplete. Augmented adult neurogenesis in response to acute and chronic injury, including HuntingtonÂs disease, has been demonstrated, but its role development, disease, and recovery is largely unknown, as are the factors controlling it. The HD gene product, huntingtin (htt) is know to interact with a number of transcription factors which subsequently influence gene expression. Understanding the factors involved in controlling neurogenesis in response to disease would bridge a significant knowledge gap and have tremendous therapeutic potential. We propose to identify transcripts responsible for CAG repeat facilitated neurogenesis. Our hypothesis is that expanded CAG repeats in the HuntingtonÂs disease gene facilitates neurogenesis by altering transcription of genes critical in neurogenesis. We have developed a model in which mouse embryonic stem cells (ESC) with expanded CAG repeats have facilitated neurogenesis. In this model more ESC with expanded CAG repeats transition to neuronal precursors and then develop into mature neurons more rapidly than control ESC. We propose to compare the gene expression profiles between ESC with expanded CAG repeats and control ESCs on days 4 and 6 of neuronal differentiation. Initial studies indicate that key transcriptional differences are occurring at these time points. Control ECS and a an ESC line with150 CAG repeats will be differentiated in triplicate, and RNA isolated form each replicate. It is anticipated that comparison of gene expression between the control and CAG repeat lines at each time point will identify transcripts involved in CAG repeat facilitated neurogenesis. Observed differences at day 4 may be more relevant to the transition from ESC to neuronal precursor whereas differences at day 6 may be more relevant to the neuronal precursor to neuron transition.

Project description:Achieving a mechanistic understanding of disease and initiating preclinical therapeutic trials necessitate the study of huntingtin toxicity and its remedy in model systems. To allow the engagement of appropriate experimental paradigms, Huntingtonâs disease (HD) models need to be validated in terms of how they recapitulate a particular aspect of human disease. In order to examine transcriptome-related effects of mutant huntingtin, we compared striatal mRNA profiles from seven genetic mouse models of disease to that of postmortem human HD caudate using microarray analysis. Transgenic models expressing short N-terminal fragments of mutant huntingtin (R6/1 and R6/2 mice) exhibited the most rapid effects on gene expression, consistent with previous studies. Although changes in the brains of knock-in models of HD took longer to appear, 15-month and 22-month CHL2Q150/Q150, 18-month HdhQ92/Q92 and 2-year-old YAC128 animals also exhibited significant HD-like mRNA signatures. When the affected genes were compared across models, a robust concordance was observed. Importantly, changes concordant across multiple lines mice were also in excellent agreement with the mRNA changes seen in human HD caudate. Although it was expected that the expression of full-length huntingtin transprotein might result in unique gene expression changes compared to those caused by expression of an N-terminal huntingtin fragment, no discernable differences between full-length and fragment models were detected. There was, however, an overall concordance between transcriptomic signature and disease stage. We thus conclude that the transcriptional changes of HD can be modelled in several available lines of transgenic mice, comprising lines expressing both N-terminal and full-length mutant huntingtin proteins. The combined analysis of mouse and human HD transcriptomes provides an important chronology of mutant huntingtin's gene expression effects. Experiment Overall Design: Striatal samples from 4 CHL2 Q150/Q150 mutant mice and 4 age-matched wild-type mice.

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Nrf2-related oxidative stress response and impaired dopamine biosynthesis in a PC12 cell model of Huntingtonâs disease

Publications

Mutant huntingtin activates Nrf2-responsive genes and impairs dopamine synthesis in a PC12 model of Huntington's disease.

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Dataset Information

Nrf2-related oxidative stress response and impaired dopamine biosynthesis in a PC12 cell model of Huntingtonâs disease

Publications

Mutant huntingtin activates Nrf2-responsive genes and impairs dopamine synthesis in a PC12 model of Huntington's disease.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

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Nrf2-related oxidative stress response and impaired dopamine biosynthesis in a PC12 cell model of Huntingtonâs disease