Project description:Hippocampal neurons exhibit heterogeneous properties, such as physiological and molecular expression patterns. To identify the gene expression patterns related to the physiological properties, we used single-cell RNA sequencing for neurons recorded juxtacellularly in vivo.
Project description:Gene expression changes induced by alpha-secretase cleaved amyloid precursor protein (sAPPalpha) in organotypic hippocampal slice cultures of male, postnatal day 15 mice (C57B6/SJL). Hippocampal slice cultures were treated with phosphate buffered saline (GSM26700, GSM26701, GSM26702) or 1 nM sAPPalpha (GSM26703, GSM26704, GSM26705) for 24 h. Each sample consists of total RNA isolated from 8-12 slices from 4 mice. Data were analyzed with MAS 5.0 and scaled to 2500. sAPPalpha induces the amyloid sequestration protein transthyretin, insulin-like growth factor 2, insulin-like growth factor binding protein 2, and other genes involved in protective pathways such as apoptosis inhibition, detoxification, and retinol transport. Keywords = Alzheimer's disease Keywords = neuroprotection Keywords = sAPPalpha
Project description:Gene expression changes induced by alpha-secretase cleaved amyloid precursor protein (sAPPalpha) in organotypic hippocampal slice cultures of male, postnatal day 15 mice (C57B6/SJL). Hippocampal slice cultures were treated with phosphate buffered saline (GSM26700, GSM26701, GSM26702) or 1 nM sAPPalpha (GSM26703, GSM26704, GSM26705) for 24 h. Each sample consists of total RNA isolated from 8-12 slices from 4 mice. Data were analyzed with MAS 5.0 and scaled to 2500. sAPPalpha induces the amyloid sequestration protein transthyretin, insulin-like growth factor 2, insulin-like growth factor binding protein 2, and other genes involved in protective pathways such as apoptosis inhibition, detoxification, and retinol transport. See Stein, TD, Anders, NJ, DeCarli, C, Chan, SL, Mattson, MP, and Johnson JA. Neutralization of transthyretin reverses the neuroprotective effects of secreted APP in APPSw mice resulting in tau phosphorylation and loss of hippocampal neurons: support for the amyloid hypothesis. J Neurosci. in press.
Project description:The neurite outgrowth inhibitory myelin protein Nogo-A has been well studied in the context of central nervous system (CNS) injury and disease. We studied the effects of the application of neutralizing anti-Nogo-A antibodies (11C7 and 7B12) in intact CNS tissue in vitro using rat organotypic hippocampal slice cultures. This study had the purpose of elucidating the role of Nogo-A in the adult intact CNS and determining the consequences of its neutralization through antibody application. In vitro cultures treated with anti-Nogo-A antibody showed an elicited growth response. The results also gave indications that hippocampal circuitry might be altered due to the regulation at the synaptic and neurotransmission level.
Project description:The neurite outgrowth inhibitory myelin protein Nogo-A has been well studied in the context of central nervous system (CNS) injury and disease. We studied the effects of the application of neutralizing anti-Nogo-A antibodies (11C7 and 7B12) in intact CNS tissue in vitro using rat organotypic hippocampal slice cultures. This study had the purpose of elucidating the role of Nogo-A in the adult intact CNS and determining the consequences of its neutralization through antibody application. In vitro cultures treated with anti-Nogo-A antibody showed an elicited growth response. The results also gave indications that hippocampal circuitry might be altered due to the regulation at the synaptic and neurotransmission level. Experiment Overall Design: Nogo-A function in the intact CNS tissue is not well known, but its neutralization in vivo produced a transitory growth response of Purkinje axons and of the corticospinal tract in intact adult rats (Buffo et al., 2000; Bareyre et al., 2002; Gianola et al., 2003). Nogo-A is relatively highly expressed in oligodendrocytes and some neurons of the hippocampus (Huber et al., 2002; Meier et al., 2003; Gil et al., 2006; Trifunovski et al., 2006). Organotypic hippocampal slice cultures are a good in vitro model to study hippocampal function and structure (Stoppini et al., 1991; 1993; Bahr, 1995; Gahwiler et al., 1997; Hakkoum et al., 2006). They mature in vitro and retain many in vivo features from a structural and functional perspective. We chose this model to study the effects of acute Nogo-A neutralization, using two function blocking monoclonal antibodies, 11C7 and 7B12 (Oertle et al., 2003; Wiessner et al., 2003; Liebscher et al., 2005), exclusively targeted against the Nogo-A specific region. Hippocampal slices from P7 Wistar rats were cultured for 21 DIV. Control untreated cultures where cultured for additional 5days for a total of 26DIV, while control IgG, and 11C7 and 7B12 were added to 21DIV cultures which were then further cultured for 5days, changing medium every 2 days. All the conditions were repeated in triplicates with separate cultures from different animals. For each condition and experimental replicate 24 cultures were pooled together before being processed for RNA extraction. Data analysis was performed by GeneSpring 7.2 (Silicon Genetics, Agilent, CA, US) comparing 11C7 and 7B12 treated samples versus Not treated and IgG treated, as controls. A present call filter (2 out of 3 present calls in at least one out of the 3 experimental replicates) was applied. Normalization was run per chip as well as per gene to the median of the control replicates. Data were statistical restricted through a 1-way Anova (pâ?¤0.05). A final threshold of â?¥1.2 fold of increase or decrease in the expression level of each single transcript was applied. Regulated transcripts have been assigned to functional categories according to GeneOntology as well as literature and database mining (Pubmed; Bioinformatics Harvester EMBL Heidelberg; Rat Genome Database).
Project description:One of the major challenges in cancer research is to find models closely resembling the tumor within patients. Human tissue slice cultures represent a promising approach to display the patient's biology ex vivo. Recently, it was shown that these slices can be successfully analyzed by whole transcriptome sequencing as well as automated histochemistry, increasing their usability as preclinical model. Glioblastoma multiforme (GBM) is a highly malignant brain tumor with poor prognosis and little is known about its genetic background and heterogeneity regarding therapy success. In this study, tissue of 25 patients with primary GBM were processed into slice cultures and treated with standard therapy (irradiation and temozolomide). Total RNA sequencing and automated histochemistry were performed to display treatment-mediated effects at a transcriptional and histological level. Slice cultures from long-term survivors (OS > 24 months) exhibited higher apoptosis than cultures from patients with shorter OS. Proliferation within these slices was slightly increased in contrast to other groups, but not significant. Among all samples, 58 protein-coding genes were upregulated and 32 downregulated in treated vs. untreated slice cultures. In general, an upregulation of DNA damage-related and cell cycle checkpoint genes as well as enrichment of genotoxicity pathways and p53-dependent signaling was found after treatment. In conclusion, we demonstrate that treatment-mediated effects in GBM slice cultures can be determined by RNA sequencing and histological staining. The slice culture model reproduces knowledge from former studies regarding transcriptomic changes and its applicability is further improved by a comprehensible correlation with survival data of the patients.
Project description:Fragile X syndrome (FXS), caused by mutations in fragile X mental retardation 1 gene (FMR1), is a prevailing genetic disorder of intellectual disability and autism. Analysis of transcriptome outcome (differentially expressed genes between WT and Fmr1 KO hippocampal neuron) associated with FXS reveal promising value of gene signature-based computation in repurposing drugs for potential practical treatment.
Project description:Background: Evidence has recently accumulated suggesting that mature hepatocytes have the unique capacity to autonomously decide their replication fate. The molecular mechanism by which hepatocytes switch from an essentially quiescent state to rapidly proliferation after liver injury is not fully understood. To provide molecular insights into the self-renewal of mature hepatocytes, we have applied an ex vivo liver slice culture system. Results: After liver injury, activation of p38 and Erk1/2 began in mature hepatocytes within 5 min. Erk1/2 was activated at the edge of the cut as well as on the surface of liver slices. The number of hepatocytes that contain activated Erk1/2 increased within 1 h and then decreased. Concomitantly, immediate early genes (IEGs), such as Jun, early gene response 1 (Egr1) and Myc were induced and Ki67 positive hepatocytes appeared 24 h after liver injury in the slices. In agreement with in vivo studies, transcriptome analysis using 2 h slice culture reveals that 63% of upregulated genes were downstream of lipopolysaccharide (LPS) stimulation which induces interleukin 6 (IL 6) or tumor necrosis factor (TNF) alpha pathways. Furthermore, circadian clock regulator, such as members of the basic helix-loop-helix family, Bhlhe40 and Bhlhe41, were highly upregulated for 4 h after injury. Although upon injury Jun or Egr1 were induced in liver slices from proliferation-defective liver, no circadian clock regulator genes were upregulated. Moreover, using an in vitro cell culture system we show that Bhlhe40 is required for the G0-G1 transition. Conclusion: Our data suggest that the circadian clock regulator, Bhlhe40, is involved in the G0-G1 transition. An ex vivo system using normal and proliferation defective KO liver is a useful tool for identification of genes that trigger cell proliferation shortly after liver injury. This method may also be applied for measurement of the liver regeneration potential of individual livers at the priming phase. In one dual-color microarray hybridization, mRNA expression changes after 2h ex vivo incubation of liver slices were examined.