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Modified cell cycle status in a mouse model of altered neuronal vulnerability (slow Wallerian degeneration; Wlds).

Wishart TM, Pemberton HN, James SR, McCabe CJ, Gillingwater TH - Genome Biol. (2008)

Bottom Line: These include the following: elevated nicotinamide adenine dinucleotide (NAD) levels associated with nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1; a part of the chimeric Wlds gene); altered mRNA expression levels of genes such as pituitary tumor transforming gene 1 (Pttg1); changes in the location/activity of the ubiquitin-proteasome machinery via binding to valosin-containing protein (VCP/p97); and modified synaptic expression of proteins such as ubiquitin-activating enzyme E1 (Ube1).We show that previous reports of diverse changes occurring downstream from Wlds expression converge upon modifications in cell cycle status.These data suggest a strong correlation between modified cell cycle pathways and altered vulnerability of axonal and synaptic compartments in postmitotic, terminally differentiated neurons.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh, UK.

ABSTRACT

Background: Altered neuronal vulnerability underlies many diseases of the human nervous system, resulting in degeneration and loss of neurons. The neuroprotective slow Wallerian degeneration (Wlds) mutation delays degeneration in axonal and synaptic compartments of neurons following a wide range of traumatic and disease-inducing stimuli, providing a powerful experimental tool with which to investigate modulation of neuronal vulnerability. Although the mechanisms through which Wlds confers neuroprotection remain unclear, a diverse range of downstream modifications, incorporating several genes/pathways, have been implicated. These include the following: elevated nicotinamide adenine dinucleotide (NAD) levels associated with nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1; a part of the chimeric Wlds gene); altered mRNA expression levels of genes such as pituitary tumor transforming gene 1 (Pttg1); changes in the location/activity of the ubiquitin-proteasome machinery via binding to valosin-containing protein (VCP/p97); and modified synaptic expression of proteins such as ubiquitin-activating enzyme E1 (Ube1).

Results: Wlds expression in mouse cerebellum and HEK293 cells induced robust increases in a broad spectrum of cell cycle-related genes. Both NAD-dependent and Pttg1-dependent pathways were responsible for mediating different subsets of these alterations, also incorporating changes in VCP/p97 localization and Ube1 expression. Cell proliferation rates were not modified by Wlds, suggesting that later mitotic phases of the cell cycle remained unaltered. We also demonstrate that Wlds concurrently altered endogenous cell stress pathways.

Conclusion: We report a novel cellular phenotype in cells with altered neuronal vulnerability. We show that previous reports of diverse changes occurring downstream from Wlds expression converge upon modifications in cell cycle status. These data suggest a strong correlation between modified cell cycle pathways and altered vulnerability of axonal and synaptic compartments in postmitotic, terminally differentiated neurons.

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Related in: MedlinePlus

Up-regulation of cell cycle genes in terminally differentiated neurons from Wlds mouse cerebellum in vivo. Three-dimensional bar chart taken from SuperArray analysis software (cell cycle specific SuperArray; see Materials and methods) showing fold difference in expression levels for 84 cell cycle related genes, comparing wild-type cerebellum (control sample) with Wlds cerebellum (test sample). Individual genes with greater than twofold expression change can be found in Table 1.
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Figure 1: Up-regulation of cell cycle genes in terminally differentiated neurons from Wlds mouse cerebellum in vivo. Three-dimensional bar chart taken from SuperArray analysis software (cell cycle specific SuperArray; see Materials and methods) showing fold difference in expression levels for 84 cell cycle related genes, comparing wild-type cerebellum (control sample) with Wlds cerebellum (test sample). Individual genes with greater than twofold expression change can be found in Table 1.

Mentions: We used cell cycle pathway-specific RT2 profiler PCR arrays (see Materials and methods [below]) to quantify and compare the expression of cell cycle-related genes with high sensitivity. Initially, we used RNA extracted from the cerebellum of wild-type and Wlds mice because this tissue has proven ideal for comparative genomic experiments [22]. Wlds cerebellar granule cells are also known to express Wlds protein at high levels and exhibit a strong neuroprotective phenotype [22]. We compared expression levels of 84 genes that regulate the cell cycle, including transitions between each of the phases, DNA replication, checkpoints, and arrest. Seventeen out of the 84 genes examined (around 20%) had expression levels increased by more than twofold in Wlds cerebellum (Figure 1 and Table 1). The array identified changes in genes associated with many different stages of the cell cycle rather than one specific stage (Table 1). Interestingly, no cell cycle related genes appeared to be suppressed greater than twofold by Wlds (Figure 1 and Table 1).


Modified cell cycle status in a mouse model of altered neuronal vulnerability (slow Wallerian degeneration; Wlds).

Wishart TM, Pemberton HN, James SR, McCabe CJ, Gillingwater TH - Genome Biol. (2008)

Up-regulation of cell cycle genes in terminally differentiated neurons from Wlds mouse cerebellum in vivo. Three-dimensional bar chart taken from SuperArray analysis software (cell cycle specific SuperArray; see Materials and methods) showing fold difference in expression levels for 84 cell cycle related genes, comparing wild-type cerebellum (control sample) with Wlds cerebellum (test sample). Individual genes with greater than twofold expression change can be found in Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2481432&req=5

Figure 1: Up-regulation of cell cycle genes in terminally differentiated neurons from Wlds mouse cerebellum in vivo. Three-dimensional bar chart taken from SuperArray analysis software (cell cycle specific SuperArray; see Materials and methods) showing fold difference in expression levels for 84 cell cycle related genes, comparing wild-type cerebellum (control sample) with Wlds cerebellum (test sample). Individual genes with greater than twofold expression change can be found in Table 1.
Mentions: We used cell cycle pathway-specific RT2 profiler PCR arrays (see Materials and methods [below]) to quantify and compare the expression of cell cycle-related genes with high sensitivity. Initially, we used RNA extracted from the cerebellum of wild-type and Wlds mice because this tissue has proven ideal for comparative genomic experiments [22]. Wlds cerebellar granule cells are also known to express Wlds protein at high levels and exhibit a strong neuroprotective phenotype [22]. We compared expression levels of 84 genes that regulate the cell cycle, including transitions between each of the phases, DNA replication, checkpoints, and arrest. Seventeen out of the 84 genes examined (around 20%) had expression levels increased by more than twofold in Wlds cerebellum (Figure 1 and Table 1). The array identified changes in genes associated with many different stages of the cell cycle rather than one specific stage (Table 1). Interestingly, no cell cycle related genes appeared to be suppressed greater than twofold by Wlds (Figure 1 and Table 1).

Bottom Line: These include the following: elevated nicotinamide adenine dinucleotide (NAD) levels associated with nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1; a part of the chimeric Wlds gene); altered mRNA expression levels of genes such as pituitary tumor transforming gene 1 (Pttg1); changes in the location/activity of the ubiquitin-proteasome machinery via binding to valosin-containing protein (VCP/p97); and modified synaptic expression of proteins such as ubiquitin-activating enzyme E1 (Ube1).We show that previous reports of diverse changes occurring downstream from Wlds expression converge upon modifications in cell cycle status.These data suggest a strong correlation between modified cell cycle pathways and altered vulnerability of axonal and synaptic compartments in postmitotic, terminally differentiated neurons.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh, UK.

ABSTRACT

Background: Altered neuronal vulnerability underlies many diseases of the human nervous system, resulting in degeneration and loss of neurons. The neuroprotective slow Wallerian degeneration (Wlds) mutation delays degeneration in axonal and synaptic compartments of neurons following a wide range of traumatic and disease-inducing stimuli, providing a powerful experimental tool with which to investigate modulation of neuronal vulnerability. Although the mechanisms through which Wlds confers neuroprotection remain unclear, a diverse range of downstream modifications, incorporating several genes/pathways, have been implicated. These include the following: elevated nicotinamide adenine dinucleotide (NAD) levels associated with nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1; a part of the chimeric Wlds gene); altered mRNA expression levels of genes such as pituitary tumor transforming gene 1 (Pttg1); changes in the location/activity of the ubiquitin-proteasome machinery via binding to valosin-containing protein (VCP/p97); and modified synaptic expression of proteins such as ubiquitin-activating enzyme E1 (Ube1).

Results: Wlds expression in mouse cerebellum and HEK293 cells induced robust increases in a broad spectrum of cell cycle-related genes. Both NAD-dependent and Pttg1-dependent pathways were responsible for mediating different subsets of these alterations, also incorporating changes in VCP/p97 localization and Ube1 expression. Cell proliferation rates were not modified by Wlds, suggesting that later mitotic phases of the cell cycle remained unaltered. We also demonstrate that Wlds concurrently altered endogenous cell stress pathways.

Conclusion: We report a novel cellular phenotype in cells with altered neuronal vulnerability. We show that previous reports of diverse changes occurring downstream from Wlds expression converge upon modifications in cell cycle status. These data suggest a strong correlation between modified cell cycle pathways and altered vulnerability of axonal and synaptic compartments in postmitotic, terminally differentiated neurons.

Show MeSH
Related in: MedlinePlus