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.
Schwamborn
Jens
J
Institute of Neurobiochemistry, University of Witten/Herdecke, Stockumer Str, 10, D-58448 Witten, Germany. JSchwamborn@yahoo.de
Lindecke
Antje
A
Elvers
Margitta
M
Horejschi
Volker
V
Kerick
Martin
M
Rafigh
Mehran
M
Pfeiffer
Julia
J
Prüllage
Maria
M
Kaltschmidt
Barbara
B
Kaltschmidt
Christian
C
D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D016000:Cluster Analysis; D004797:Enzyme-Linked Immunosorbent Assay; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D018932:Chemokine CCL2; D014409:Tumor Necrosis Factor-alpha