Ethanol inhibits the proliferation of neural stem cells in the fetal, adolescent, and adult brain. The consequences are cognitive deficits associated with fetal alcohol spectrum disorder and alcohol use disorder. We tested the hypothesis that ethanol affects progression through cell cycle checkpoints by differentially modifying transcriptional processes. Monolayer cultures of NS-5 neural stem cells were treated for 48 hr with the mitogenic agent FGF2 or the anti-mitogenic TGF1 in the absence or presence of ethanol. Cell cycle elongation was induced by a global down-regulation of genes involved in cell cycle progression, including the cyclin E system. Checkpoint regulation occurred downstream of p21 and Jun-oncogene signaling cascades. Thus, ethanol can affect cell cycle progression by altering transcript expression of strategic genes downstream of the G1/S checkpoint.
Ethanol-induced methylation of cell cycle genes in neural stem cells.
Specimen part, Treatment
View SamplesDespite its key role in Alzheimer pathogenesis, the physiological function(s) of the amyloid precursor protein (APP) and of its proteolytic fragments are still poorly understood. The secreted APPs ectodomain has been shown to be involved in neuroprotection and synaptic plasticity. The -secretase generated APP intracellular domain, AICD, functions as a transcriptional regulator in heterologous reporter assays although its role for endogenous gene regulation has remained controversial. Previously, we have generated APPs knockin (KI) mice expressing solely the secreted ectodomain APPs. Here, we generated double mutants (APPs-DM) by crossing APPs-KI mice onto an APLP2-deficient background and show that APPs rescues the postnatal lethality of the majority of APP/APLP2 double knockout mice. Despite normal CNS morphology and unaltered basal synaptic transmission, young APPs-DM mice already showed pronounced hippocampal dysfunction, impaired spatial learning and a deficit in LTP. To gain further mechanistic insight into which domains/proteolytic fragments are crucial for hippocampal APP/APLP2 mediated functions, we performed a DNA microarray transcriptome profiling of prefrontal cortex and hippocampus of adult APLP2-KO (APLP2-/-) and APPs-DM mice (APP/APLP2-/- mice).Interestingly, this analysis failed to reveal major genotype-related transcriptional differences. Expression differences between cortex and hippocampus were, however, readily detectable.
APP and APLP2 are essential at PNS and CNS synapses for transmission, spatial learning and LTP.
Sex, Specimen part
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