Transcriptome changes in the Alzheimer's middle temporal gyrus: importance of RNA metabolism and mitochondria-associated membrane (MAM) genes
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ABSTRACT:
PROVIDER: PRJNA549443 | ENA |
REPOSITORIES: ENA
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Project description:We used Illumina Human HT-12 v4 arrays to compare RNA expression of middle temporal gyrus (MTG; BA21) in Alzheimer’s Disease (AD = 97) and non-demented controls (ND = 98). A total of 938 transcripts were highly differentially expressed (adj p < 0.01; log2 Fold Change (FC) ≥ |0.500|, with 411 overexpressed and 527 underexpressed in AD. Our results correlated with expression profiling in neurons from AD and ND obtained by Laser Capture Microscopy in MTG from an independent dataset (log2 FC correlation: r = 0.504; p = 2.2e-16). Additionally selected effects were validated by qPCR. ANOVA analysis yielded no difference between genders in response to AD, but some gender specific genes were detected (e.g: IL8 and AGRN in males, and HSPH1 and GRM1 in females). Several transcripts were associated with Braak Staging (e.g AEBP1 and DNALI1), ante-mortem MMSE (e.g. AEBP1 and GFAP) and Tangle density (eg. RNU1G2, and DNALI1). At the pathway level we detected enrichment of Synaptic Vesicle Processes and GABAergic transmission genes. Finally, applying the Weighted Correlation Network Analysis (WGCNA) we identified 4 expression modules enriched for neuronal and synaptic genes, mitochondria-associated membrane (MAM), chemical stimulus and olfactory receptor and non-coding RNA metabolism genes. Our results represent an extensive description of MTG mRNA profiling in a large sample of AD and ND. These data provide a list of genes associated with AD, and correlated to neurofibrillary tangles density. In addition, these data emphasize the importance of mitochondrial membranes and transcripts related to olfactory receptors in AD.
2019-06-19 | GSE132903 | GEO
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Project description:Amyotrophic lateral sclerosis (ALS) is a rapidly progressive, fatal neurodegenerative disorder, characterized by selective loss of motor neurons (MNs). A number of causative genetic mutations underlie the disease, including mutations in the fused in sarcoma (FUS) gene, which can lead to both juvenile and late onset ALS. Although ALS results from MN’s death, there is evidence that dysfunctional glial cells, including oligodendroglia, contribute to neurodegeneration. Here, we used human induced pluripotent stem cells (hiPSCs) with a FUSR521H or a FUSP525L mutation and their isogenic controls to generate oligodendrocyte progenitor cells (OPCs) by inducing SOX10 expression from a TET-On SOX10 cassette as described previously in our lab. Mutant and control iPSC differentiated efficiently into OPCs. RNA sequencing identified a myelin sheath-related phenotype in mutant OPCs. Subsequent lipidomics studies demonstrated defects in myelin lipids, with a reduction of phospholipids in mutant OPCs. Among them, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are the most two abundant phospholipid in mammalian cells and regulate the mitochondria-associated ER membrane (MAM) integrity. Interestingly, FUSR521H mutant OPCs displayed a decrease in the PC/PE ratio, known to be associated with maintaining membrane (mitochondria) integrity. Proximity ligation assay further indicated that MAM was diminished in mutant OPCs. Moreover, mutant OPCs displayed stronger activation of unfolded protein response markers, a hallmark of increased susceptibility to endoplasmic reticulum (ER) stress, when exposed to thapsigargin, and exhibited impaired mitochondrial respiration and reduced Ca2+ signaling from ER Ca2+ stores. Taken together, these results demonstrate that FUS mutant OPCs display defects in lipid metabolism associated with MAM disruption manifested by impaired mitochondrial metabolism with increased susceptibility to ER stress and suppressed physiological Ca2+ signaling events.
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Project description:Mitochondrial function is modulated by its functional interaction with the endoplasmic reticulum. Recent research indicates that these contacts are disrupted in familial models of amyotrophic lateral sclerosis. We report here this impairment in the crosstalk between mitochondria and the endoplasmic reticulum impedes the use of glucose-derived pyruvate as mitochondrial fuel, causing a shift to fatty acids to sustain energy production. Over time, this deficiency alters mitochondrial electron flow and the active/dormant status of complex I in spinal cord tissues, but not in the brain. These findings suggest MAM plays a crucial role in regulating cellular glucose metabolism and that its dysfunction may underlie the bioenergetic deficits observed in ALS.
2024-07-19 | PXD053253 | Pride
Project description:Methylazoxymethanol (MAM), the genotoxic metabolite of the cycad azoxyglucoside cycasin, induces genetic alterations in bacteria, yeast, plants, insects and mammalian cells, but adult nerve cells are thought to be unaffected. We show that the brains of young adult mice treated with a single systemic dose of MAM display DNA damage (O6-methylguanine lesions) that peaks at 48 hours and decline to near-normal levels at 7 days post-treatment. By contrast, at this time, MAM-treated mice lacking the gene encoding the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT), showed persistent O6-methylguanine DNA damage. The DNA damage was linked to cell-signaling pathways that are perturbed in cancer and neurodegenerative disease. These data are consistent with the established carcinogenic and developmental neurotoxic properties of MAM in rodents, and they support the proposal that cancer and neurodegeneration share common signal transduction pathways. They also strengthen the hypothesis that early life exposure to the MAM glucoside cycasin has an etiological association with a declining, prototypical neurodegenerative disease seen in Guam, Japan, and New Guinea populations that formerly used the neurotoxic cycad plant for medicine and/or food. Exposure to environmental genotoxins may have relevance to the etiology of related tauopathies, notably, Alzheimer’s disease, as well as cancer. Mouse brains from eleven-week-old male C57BL6 wild-type and Mgmt-/- mice were exposed to either MAM or Vehicle for 6 hr, 24 hr, 48 hr, 168 hr. Five or six mice per group for a total of 94 mice.
2013-01-10 | E-GEOD-26600 | biostudies-arrayexpress
Project description:Gestational and perinatal disruption of neural development increases the risk of developing schizophrenia (SCZ) later in life. Embryonic day 17 (E17) methylazoxymethanol (MAM) treatment leads to histological, physiological and behavioural abnormalities in post-puberty rats resembling those described in SCZ patients. However, the validity of E17 MAM-exposed mice as a SCZ model has not been explored. Here we treated E17 C57BL/6 mouse dams with various dosages of MAM. We found that this mouse strain was more vulnerable to MAM treatment than rats and there were gender difference in behavioural abnormalities, histological changes and prefrontal cortical gene expression profiles in MAM (7.5 mg/kg)-exposed mice. Both male and female MAM-exposed mice had deficits in prepulse inhibition but were normal in social interaction and novel object recognition tasks. Female MAM-exposed mice were hyperactive in spontaneous locomotion while male mice were normal. Consistently, only female MAM-exposed mice exhibited reduced brain weight, decreased size of prefrontal cortex (PFC) and enlarged lateral ventricles. Transcriptome analysis of the PFC revealed that there were more differentially expressed genes in female MAM-exposed mice than those in male mice. Moreover, expression of Pvalb, Arc and genes in their association networks were downregulated in the PFC of female MAM-exposed mice. These results show that E17 MAM-exposure in C57BL/6 mice leads to behavioural changes that mimic positive symptoms and sensorimotor gating deficits associated with SCZ. MAM-exposed female mice may be used to study gene expression changes, inhibitory neural circuit dysfunction and glutamatergic synaptic plasticity deficits related to SCZ.
2019-01-09 | GSE108925 | GEO
Project description:Mitochondrial function is modulated by its functional interaction with the endoplasmic reticulum. Recent research indicates that these contacts are disrupted in familial models of amyotrophic lateral sclerosis. We report here this impairment in the crosstalk between mitochondria and the endoplasmic reticulum impedes the use of glucose-derived pyruvate as mitochondrial fuel, causing a shift to fatty acids to sustain energy production. Over time, this deficiency alters mitochondrial electron flow and the active/dormant status of complex I in spinal cord tissues, but not in the brain. These findings suggest MAM plays a crucial role in regulating cellular glucose metabolism and that its dysfunction may underlie the bioenergetic deficits observed in ALS.
2024-07-19 | PXD053415 | Pride
Project description:Methylazoxymethanol (MAM), the genotoxic metabolite of the cycad azoxyglucoside cycasin, induces genetic alterations in bacteria, yeast, plants, insects and mammalian cells, but adult nerve cells are thought to be unaffected. We show that the brains of young adult mice treated with a single systemic dose of MAM display DNA damage (O6-methylguanine lesions) that peaks at 48 hours and decline to near-normal levels at 7 days post-treatment. By contrast, at this time, MAM-treated mice lacking the gene encoding the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT), showed persistent O6-methylguanine DNA damage. The DNA damage was linked to cell-signaling pathways that are perturbed in cancer and neurodegenerative disease. These data are consistent with the established carcinogenic and developmental neurotoxic properties of MAM in rodents, and they support the proposal that cancer and neurodegeneration share common signal transduction pathways. They also strengthen the hypothesis that early life exposure to the MAM glucoside cycasin has an etiological association with a declining, prototypical neurodegenerative disease seen in Guam, Japan, and New Guinea populations that formerly used the neurotoxic cycad plant for medicine and/or food. Exposure to environmental genotoxins may have relevance to the etiology of related tauopathies, notably, Alzheimer’s disease, as well as cancer.
2013-01-10 | GSE26600 | GEO