Abstract
Cellular and molecular mechanisms of methamphetamine (METH)‐induced neurotoxicity may involve alterations of cellular redox status and induction of inflammatory genes in endothelial cells. To study these hypotheses, molecular signaling pathways of METH‐induced inflammatory responses via activation of redox‐sensitive transcription factors were investigated in human brain microvascular endothelial cells (HBMEC). A dose‐dependent depletion of total glutathione levels was detected in HBMEC exposed to METH. In addition, electrophoretic mobility shift assay (EMSA) showed significant increases in DNA binding activities of redox‐responsive transcription factors, AP‐1 and NF‐κB, in HBMEC treated with METH. METH‐mediated AP‐1 or NF‐κB activation was accompanied by induction of transactivation of AP‐1 or NF‐κB, as measured by dual luciferase assay using specific reporter plasmids. Because NF‐κB and AP‐1 are known to regulate expression of inflammatory genes, expression of the gene encoding for tumor necrosis factor‐α (TNF‐α) was also studied in METH‐treated HBMEC. A dose‐dependent overexpression of the TNF‐α gene was observed in HBMEC treated with METH. The importance of AP‐1 and NF‐κB in METH‐induced TNF‐α gene was confirmed in functional promoter studies using constructs of the TNF‐α promoter with mutated AP‐1 or NF‐κB sites. These results indicate that METH‐induced disturbances in cellular redox status and activation of AP‐1 and NF‐κB can play critical roles in the signaling pathways leading to upregulation of inflammatory genes in human brain endothelial cells. J. Neurosci. Res. 66:583–591, 2001. © 2001 Wiley‐Liss, Inc.