The -amyloid precursor protein APP and the related APLPs, undergo complex proteolytic processing giving rise to several fragments. Whereas it is well established that A accumulation is a central trigger for Alzheimer disease (AD), the physiological role of APP family members and their diverse proteolytic products is still largely unknown. 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 transciptional regulator in heterologous reporter assays, although its role for endogenous gene regulation has remained controversial. To gain further insight into the molecular changes associated with knockout phenotypes and to elucidate the physiological functions of APP family members including their proposed role as transcriptional regulators we performed a DNA microarray transcriptome profiling of the frontal cortex of adult wild type, APP-/-, APLP2-/- and APPs knockin (KI) mice, APP/, expressing solely the secreted APPs ectodomain. Biological pathways affected by the lack of APP family members included regulation of neurogenesis, regulation of transcription and regulation of neuron projection development. Comparative analysis of transcriptome changes and qPCR validation identified co-regulated gene sets. Interestingly, these included heat shock proteins and plasticity related genes that were down-regulated in knock-out cortices. In contrast, we failed to detect significant differences in expression of previously proposed AICD target genes including Bace1, Kai1, Gsk3b, p53, Tip60 and Vglut2. Only Egfr was slightly up-regulated in APLP2-/- mice. Comparison of APP-/- and APP/ with wild-type mice revealed a high proportion of co-regulated genes indicating an important role of the C-terminus for cellular signaling. Finally, comparison of APLP2-/- on different genetic backgrounds revealed that background related transcriptome changes may dominate over changes due to the knockout of a single gene. Shared transcriptome profiles corroborated closely related physiological functions of APP family members in the adult central nervous system. As expression of proposed AICD target genes was not altered in adult cortex, this may indicate that these genes are not affected by lack of APP under resting conditions or only in a small subset of cells.
Comparative transcriptome profiling of amyloid precursor protein family members in the adult cortex.
Sex, Specimen part
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
View SamplesNo description.
No associated publication
Sex, Specimen part, Cell line, Treatment
View SamplesWe profiled transcripts from sorted phloem cells of wild-type and apl mutants to identify the genes regulated by APL in phloem.
Plant development. Arabidopsis NAC45/86 direct sieve element morphogenesis culminating in enucleation.
Specimen part
View SamplesTo examine the transcriptome alteration caused by ZIC5 knockdown in melanoma, we performed gene expression microarray analysis.
ZIC5 Drives Melanoma Aggressiveness by PDGFD-Mediated Activation of FAK and STAT3.
Cell line
View Samplesprofiling gene transcription in a mouse model of permanent focal cerebral ischemia that was induced by middle cerebral artery occlusion (MCAO)
Discovery of transcriptional programs in cerebral ischemia by in silico promoter analysis
Specimen part, Treatment, Time
View SamplesAlzheimer's disease (AD) is characterized by massive neurodegeneration and multiple changes in cellular processes, including neurogenesis. Proteolytic processing of the amyloid precursor protein (APP) plays a central role in AD. Due to varying APP processing, several beta-amyloid peptides are generated. In contrast to the form with 40 amino acids, the variant with 42 amino acids is thought to be the pathogenic form triggering the pathophysiological cascade in AD. Here, we studied the transcriptomic response to increased or decreased Abeta42 levels generated in human neuroblastoma cells. Genome-wide expression profiles (Affymetrix)were used to analyze the cellular response to the changed Abeta42 and Abeta40-levels. <br></br><br></br>Human neuroblastoma cell line SH-SY5Y is a thrice cloned (SK-N-SH -> SH-SY -> SH-SY5 -> SH-SY5Y) subline of the neuroblastoma cell line SK-N-SH which was isolated and established in 1970. This cell line has 47 chromosomes. The cells possess a unique marker comprised of a chromosome 1 with a complex insertion of an additional copy of a 1q segment into the long arm, resulting in trisomy of 1q. The cell lines used in this study are SHSY5Y transfected with the constructs pCEP-C99I45F, pCEP-C99V50F, pCEP-C99 wildtype or mock transfected with an empty vector. Independent cell clones of each transfected line were used to provide biological replicates.<br></br> Overexpressed C99 I45F is intracellularly cleaved resulting in high Abeta42, but low Abeta40 levels.<br></br> Overexpressed C99V50F is intracellularly cleaved resulting in low Abeta42, but high Abeta40 levels.<br></br>Overexpressed C99 wildtype is intracellularly cleaved resulting in medium Abeta42 and Abeta40 levels<br></br>Mock is the SHSY5Y cell line transfected with the empty vector pCEP (Invitrogen) as a negative control
New Alzheimer amyloid beta responsive genes identified in human neuroblastoma cells by hierarchical clustering.
Cell line, Subject
View SamplesCalyx of Held giant presynaptic terminals in the medial nucleus of the trapezoid body of the auditory brainstem form axosomatic synapses that have advanced to one of the best-studied synaptic system of the mammalian brain. As the auditory system matures and adjusts to high fidelity synaptic transmission, the calyx undergoes extensive structural and functional changes: it is formed around postnatal day 3 (P3), achieves immature function until hearing onset around P10 and can be considered mature from P21 onwards. This setting provides the unique opportunity to examine the repertoire of genes driving synaptic structure and function.
Gene expression profile during functional maturation of a central mammalian synapse.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
No associated publication
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Alteration of mRNA and microRNA expression profiles in rat muscular type vasculature in early postnatal development.
Sex
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