Project description: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. To assess the influence of PrPC on gene expression profile during development in the mouse brain, we undertook a microarray analysis by using RNA isolated from the hippocampus, at two different developmental stages: newborn (4-day-old) and adult (3-month-old) mice, both from Prnp+/+ and Prnp0/0 animals. The comparison of the different datasets allowed us to identify “commonly” co-regulated genes and “uniquely” de-regulated genes during postnatal development in these animal models. The lack of PrPC during neuronal development affected several biological pathways, among which the most representative were cell signaling, cell-cell communication and transduction process. In addition, the absence of PrPC influenced genes involved in calcium homeostasis, nervous system development, synaptic transmission and cell adhesion. There was only a moderate alteration of the gene expression profile during neuronal development in the animal models we studied. PrPC deficiency does not lead to a dramatic alteration of gene expression profile, and produces moderate altered gene expression levels from young to adult animals. Thus, our results may provide additional support to silencing endogenous PrPC levels as a therapeutic approach to prion diseases.

Project description: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. To assess the influence of PrPC on gene expression profile during development in the mouse brain, we undertook a microarray analysis by using RNA isolated from the hippocampus, at two different developmental stages: newborn (4-day-old) and adult (3-month-old) mice, both from Prnp+/+ and Prnp0/0 animals. The comparison of the different datasets allowed us to identify “commonly” co-regulated genes and “uniquely” de-regulated genes during postnatal development in these animal models. The lack of PrPC during neuronal development affected several biological pathways, among which the most representative were cell signaling, cell-cell communication and transduction process. In addition, the absence of PrPC influenced genes involved in calcium homeostasis, nervous system development, synaptic transmission and cell adhesion. There was only a moderate alteration of the gene expression profile during neuronal development in the animal models we studied. PrPC deficiency does not lead to a dramatic alteration of gene expression profile, and produces moderate altered gene expression levels from young to adult animals. Thus, our results may provide additional support to silencing endogenous PrPC levels as a therapeutic approach to prion diseases. To analyze the influence of PrPC expression on CNS gene expression profile during development, we investigated WT PrPC (Prnp+/+) and Prnp0/0 mice at two different developmental stages: in neonatal animals (postnatal day 4, P4) and in adult animals (3 months old). For each developmental stage, hippocampi of 3 (pups) or 4 (adult) animals were dissected immediately after animal sacrifice and promptly processed for RNA extraction and purification, for a total of 14 samples.

Project description:RET/GDNF and ET3/EDNRB regulate cell survival, differentiation and migration of neural crest-derived cells. Many signalling mediators of RET have been characterized but the target genes at the end of the signalling cascade are largely unknown. Since the RET/EDNRB crosstalk has been previously shown, we used a Caenorhabditis elegans knockout strain of Nep-1, a homologue of human ECE1 (endothelin-converting enzyme-1), to identify new target genes. Transcriptome comparison between wild-type and Nep-1 strains at different stages identified vit-3 as a differentially expressed gene. Molecular studies of the vit3 mammalian homologue, Apoliporotein B (APOB), were performed in the murine Neuro2a cell line, a model of ENS development. Apob expression in Neuro2a is specifically activated by the RET/GDNF signalling pathway, since Ret silencing abolished Apob increase, and this effect is induced by MAPK P38 kinase activation. Mouse Apob promoter study revealed that there is a p53-dependent repressor element in the promoter region which blocks Apob expression and we show that actually p53 binds to this region. We demonstrated that RET/GDNF and EDNRB/endothelin 3 (ET-3) cooperate in inducing neuronal differentiation resulting in Apob activation. We also show that Apob expression is downregulated in mouse embryos homozygous for the mutation RetC620R and presenting a severe HSCR phenotype, whereas heterozygous mice, phenotypically normal, present a significant increase in Apob expression. These data suggest that Apob has an important role in RET-mediated neuronal development and APOB decrease may have an impact in human disorders where RET absence has been already identified, such as HSCR and Parkinson disease. Gene expression analysis using Affymetrix GeneChip C. elegans arrays in order to identify genes up- or down-regulated in nep-1 strains, homologue of human ECE1 (endothelin-converting enzyme 1). Comparison of the transcriptomes between wt and nep-1 strains in larval stage L3 and adult C. elegans.

Dataset Information

Mus musculus

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets