blockade of trpm7 channel activity and cell death by inhibitors of 5-lipoxygenase封锁trpm7通道活动和细胞死亡5-lipoxygenase的抑制剂.pdfVIP

Blockade of TRPM7 Channel Activity and Cell Death by Inhibitors of 5-Lipoxygenase 1 2 2 1 2 1 Hsiang-Chin Chen , Jia Xie , Zheng Zhang , Li-Ting Su , Lixia Yue *, Loren W. Runnels * 1 Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, United States of America, 2 Calhoun Cardiology Center and Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America Abstract TRPM7 is a ubiquitous divalent-selective ion channel with its own kinase domain. Recent studies have shown that suppression of TRPM7 protein expression by RNA interference increases resistance to ischemia-induced neuronal cell death in vivo and in vitro, making the channel a potentially attractive pharmacological target for molecular intervention. Here, we report the identification of the 5-lipoxygenase inhibitors, NDGA, AA861, and MK886, as potent blockers of the TRPM7 channel. Using a cell-based assay, application of these compounds prevented cell rounding caused by overexpression of TRPM7 in HEK-293 cells, whereas inhibitors of 12-lipoxygenase and 15-lipoxygenase did not prevent the change in cell morphology. Application of the 5-lipoxygenase inhibitors blocked heterologously expressed TRPM7 whole-cell currents without affecting the protein’s expression level or its cell surface concentration. All three inhibitors were also effective in blocking the native TRPM7 current in HEK-293 cells. However, two other 5-lipoxygenase specific inhibitors, 5,6-dehydro- arachidonic acid and zileuton, were ineffective in suppressing TRPM7 channel activity. Targe