Biomedical subjects

Antje Lindecke

Publications and source records attributed to Antje Lindecke.

5 recordsLinked to original sources

PubMed2006

Long-term depression activates transcription of immediate early transcription factor genes: involvement of serum response factor/Elk-1.

Long-term depression (LTD) is one of the paradigms used in vivo or ex vivo for studying memory formation. In order to identify genes with potential relevance for memory formation we used mouse organotypic hippocampal slice cultures in which chemical LTD was induced by applications of 3,5-dihydroxyphenylglycine (DHPG). The induction of chemical LTD was robust, as monitored electrophysiologically. Gene expression analysis after chemical LTD induction was performed using cDNA microarrays containing >7,000 probes. The DHPG-induced expression of immediate early genes (c-fos, junB, egr1 and nr4a1) was subsequently verified by TaqMan polymerase chain reaction. Bioinformatic analysis suggested a common regulator element [serum response factor (SRF)/Elk-1 binding sites] within the promoter region of these genes. Indeed, here we could show a DHPG-dependent binding of SRF at the SRF response element (SRE) site within the promoter region of c-fos and junB. However, SRF binding to egr1 promoter sites was constitutive. The phosphorylation of the ternary complex factor Elk-1 and its localization in the nucleus of hippocampal neurones after DHPG treatment was shown by immunofluorescence using a phosphospecific antibody. We suggest that LTD leads to SRF/Elk-1-regulated gene expression of immediate early transcription factors, which could in turn promote a second broader wave of gene expression.

Animals↗

PubMed2006

NF-kappaB regulates spatial memory formation and synaptic plasticity through protein kinase A/CREB signaling.

Synaptic activity-dependent de novo gene transcription is crucial for long-lasting neuronal plasticity and long-term memory. In a forebrain neuronal conditional NF-kappaB-deficient mouse model, we demonstrate here that the transcription factor NF-kappaB regulates spatial memory formation, synaptic transmission, and plasticity. Gene profiling experiments and analysis of regulatory regions identified the alpha catalytic subunit of protein kinase A (PKA), an essential memory regulator, as a new NF-kappaB target gene. Consequently, NF-kappaB inhibition led to a decrease in forskolin-induced CREB phosphorylation. Collectively, these results disclose a novel hierarchical transcriptional network involving NF-kappaB, PKA, and CREB that leads to concerted nuclear transduction of synaptic signals in neurons, accounting for the critical function of NF-kappaB in learning and memory.

Animals↗

PubMed2005

A microarray analysis of developmentally regulated genes during macronuclear differentiation in the stichotrichous ciliate Stylonychia lemnae.

After sexual reproduction in ciliated protozoa a new macronucleus differentiates from a micronuclear derivative. In the course of macronuclear development dramatic DNA- and chromatin reorganisation processes occur, which include splicing of DNA sequences such as IES (internal eliminated sequences) and transposon-like elements during formation of polytene chromosomes, degradation of the polytene chromosomes and specific elimination of micronuclear-specific DNA, de novo addition of telomeres and specific amplification of DNA sequences. In order to understand the molecular basis of this nuclear differentiation process, analysis of developmentally regulated genes seems to be a necessary prerequisite. We performed a microarray analysis to identify genes differentially expressed during macronuclear differentiation. 467 sequences from cDNA libraries were identified as possible candidates from which 384 sequences were further characterised by sequence analysis. These sequences were identified, if possible, by DNA and protein BLAST analysis. Expression of one of these sequences was silenced by RNAi and a preliminary functional analysis performed. Results presented in this study provide the basis for a functional characterisation of genes differentially expressed during this nuclear differentiation process.

Animals↗

PubMed2004

Induction of a metastatogenic tumor cell type by neurotransmitters and its pharmacological inhibition by established drugs.

The active migration of tumor cells, a crucial requirement for metastasis development and cancer progression, is regulated by signal substances including neurotransmitters. We investigated the migration of tumor cells within a three-dimensional collagen matrix using time-lapse videomicroscopy and computer-assisted analysis of the migration path. Tumor cell migration is induced by norepinephrine, dopamine and substance P. We show that this induced migration, using MDA-MB-468 breast and PC-3 prostate carcinoma cells, can be inhibited by using specific, clinically established receptor antagonists to the beta2-adrenoceptor, the D2 receptor, or the neurokinin-1 receptor, respectively. All of the investigated neurotransmitters significantly activated the cyclic adenosine-monophosphate response element binding protein (CREB). Furthermore, microarray analysis revealed changes of gene expression toward a highly motile tumor cell type, including an upregulation of the alpha2 integrin, which is an essential adhesion receptor for collagen in migration. The gene for the tumor suppressor gelsolin was downregulated. These 2 critical alterations were confirmed on the protein level by flow-cytometry and immunoblotting, respectively. Neurotransmitters thus induce a metastatogenic tumor cell type by directly regulating gene expression and increased migratory activity, which can be prevented by established neurotransmitter antagonists.

Breast Neoplasms↗

PubMed2003

Microarray analysis of tumor necrosis factor alpha induced gene expression in U373 human glioblastoma cells.

BACKGROUND: Tumor necrosis factor alpha (TNF) is able to induce a variety of biological responses in the nervous system including inflammation and neuroprotection. Human astrocytoma cells U373 have been widely used as a model for inflammatory cytokine actions in the nervous system. Here we used cDNA microarrays to analyze the time course of the transcriptional response from 1 h up to 12 h post TNF treatment in comparison to untreated U373 cells. TNF activated strongly the NF-kappaB transcriptional pathway and is linked to other pathways via the NF-kappaB target genes JUNB and IRF-1. Part of the TNF-induced gene expression could be inhibited by pharmacological inhibition of NF-kappaB with pyrrolidine-dithiocarbamate (PDTC). NF-kappaB comprises a family of transcription factors which are involved in the inducible expression of genes regulating neuronal survival, inflammatory response, cancer and innate immunity. RESULTS: In this study we show that numerous genes responded to TNF (> 880 from 7500 tested) with a more than two-fold induction rate. Several novel TNF-responsive genes (about 60% of the genes regulated by a factor > or = 3) were detected. A comparison of our TNF-induced gene expression profiles of U373, with profiles from 3T3 and Hela cells revealed a striking cell-type specificity. SCYA2 (MCP-1, CCL2, MCAF) was induced in U373 cells in a sustained manner and at the highest level of all analyzed genes. MCP-1 protein expression, as monitored with immunofluorescence and ELISA, correlated exactly with microarray data. Based on these data and on evidence from literature we suggest a model for the potential neurodegenerative effect of NF-kappaB in astroglia: Activation of NF-kappaB via TNF results in a strongly increased production of MCP-1. This leads to a exacerbation of neurodegeneration in stoke or Multiple Sclerosis, presumably via infiltration of macrophages. CONCLUSIONS: The vast majority of genes regulated more than 3-fold were previously not linked to tumor necrosis factor alpha as a search in published literature revealed. Striking co-regulation for several functional groups such as proteasome and ribosomal proteins were detected.

Cell Line, Tumor↗