Heparin is a classic anticoagulant that is commonly used in the treatment of acute ischemic stroke (AIS). Its use remains controversial, however, due to the risk of cerebral hemorrhagic transformation. In addition to anticoagulant effects, diverse effects on transcription factors can be caused by heparin. Among the transcription factors potentially affected is nuclear factor kappa B (NF-κB), a protein that is reportedly related to the survival of cerebral endothelial cells. We investigated the effect of heparin on NF-κB activation and cell death following oxygen-glucose deprivation (OGD), an experimental model of AIS. We subjected bEnd.3 cells from a murine cerebral microvascular endothelial cell line to OGD. We examined the effect of heparin on OGD-induced NF-κB activation and its mechanism of action, using electrophoretic mobility shift assays, reporter gene analysis, real-time RT-PCR, Western blot analysis, and confocal microscopy. We also measured the effect of heparin on OGD-induced cell death using an MTT assay. Heparin inhibited both tumor necrosis factor α- and OGD-induced NF-κB activation. Heparin was taken up by endocytosis and then entered the nucleus. Heparin did not affect the nuclear translocation of NF-κB, but instead inhibited the DNA binding of NF-κB in the nucleus. Cells were more susceptible to OGD-induced cell death after heparin treatment. Besides producing an anticoagulation effect, heparin also inhibits NF-κB activation, resulting in increased susceptibility to OGD-induced cell death. This effect may be responsible for hemorrhagic transformation in patients following heparin treatment for AIS.
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Acknowledgements Reporter plasmids expressing luciferase were kindly provided by Dr. Guy Haegeman (Flanders Interuniversity Institute for Biotechnology and University of Gent, Belgium). This study was supported by a Faculty Research Grant of Yonsei University College of Medicine for 2004 (6-2004-1078)
All Science Journal Classification (ASJC) codes
- Cellular and Molecular Neuroscience