Allelic imbalance of tissue-type plasminogen activator (t-PA) gene expression in human brain tissue

Anna Tjarnlund-Wolf, Karin Hultman, Maurice Curtis, Richard Faull, Robert Medcalf, Christina Jern

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Abstract

We have identified a single-nucleotide polymorphism (SNP) in the t-PA enhancer (-7351C>T), which is associated with endothelial t-PA release in vivo. In vitro studies demonstrated that this SNP is functional at the level of transcription. In the brain, t-PA has been implicated in both physiologic and pathophysiologic processes. The aim of the present study was to examine the effect of the t-PA -7351C>T SNP on t-PA gene expression in human brain tissue. Allelic mRNA expression was measured in heterozygous post-mortem brain tissues using quantitative TaqMan genotyping assay. Protein-DNA interactions were assessed using electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). Significantly higher levels of t-PA mRNA were generated from chromosomes that harboured the wild-type -7351C allele, as compared to those generated from the mutant T allele (for the hippocampus, C to T allelic ratio of a??1.3, p=0.010, n=12; and for the cortex, C to T allelic ratio of a??1.2, p=0.017, n=12). EMSA showed reduced neuronal and astrocytic nuclear protein binding affinity to the T allele, and identified Sp1 and Sp3 as the major transcription factors that bound to the -7351 site. ChIP analyses confirmed that Sp1 recognises this site in intact cells. In conclusion, the t-PA -7351C>T SNP affects t-PA gene expression in human brain tissue. This finding might have clinical implications for neurological conditions associated with enhanced t-PA levels, such as in the acute phase of cerebral ischaemia, and also for stroke recovery. A? Schattauer 2011.
Original languageEnglish
Pages (from-to)945 - 953
Number of pages9
JournalThrombosis and Haemostasis
Volume105
Issue number6
DOIs
Publication statusPublished - 2011

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