Abstract
Exposure of SH-SY5Y neuroblastoma or rat cortical neurons to diethylenetriamine-NO (DETA-NO) rapidly depolarized mitochondria. In SH-SY5Y DETA-NO activated caspase 3 and produced cell death. Mitochondrial depolarization in SH-SY5Y was visualized both with JC-1 accumulation and as dequenching of calcein fluorescence in mitochondria initially loaded with calcein-AM and tetramethylrhodamine methyl ester (TMRM). Calcein/TMRM-visualized mitochondrial depolarization was prevented by cyclosporin A (CsA) or approximately two-fold increased levels of BclXL protein. Dynamic imaging of mitochondrial potential (Deltapsi M) with TMRM showed that DETA-NO induced cycles of mitochondrial depolarization/repolarization ("flickering"). Fifteen-30 min of DETA-NO exposure caused high-frequency flickering with small peak size; 2 h of DETA-NO produced large peaks with prolonged depolarization. NO-induced flickering but not that from Bax was blocked by the calcium uniporter antagonist Ru360. Our findings show rapid-onset, dynamic regulation of Deltapsi M by NO, implying that neuroprotective therapies for brain ischemia target cell death processes downstream of effects of NO on mitochondria.
Publication types
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Brain Ischemia / drug therapy
-
Brain Ischemia / metabolism*
-
Brain Ischemia / physiopathology
-
Calcium Channels
-
Calcium-Binding Proteins / antagonists & inhibitors
-
Calcium-Binding Proteins / metabolism
-
Caspase 3
-
Caspases / drug effects
-
Caspases / metabolism
-
Cell Death / drug effects
-
Cell Death / physiology*
-
Cell Membrane Permeability / drug effects
-
Cell Membrane Permeability / physiology
-
Cyclosporine / pharmacology
-
Dose-Response Relationship, Drug
-
Fluorescent Dyes
-
Humans
-
Intracellular Membranes / drug effects
-
Intracellular Membranes / metabolism
-
Ion Channels / drug effects
-
Ion Channels / metabolism*
-
Membrane Potentials / drug effects
-
Membrane Potentials / physiology
-
Mitochondria / drug effects
-
Mitochondria / metabolism*
-
Nerve Degeneration / drug therapy
-
Nerve Degeneration / metabolism*
-
Nerve Degeneration / physiopathology
-
Neurons / drug effects
-
Neurons / metabolism*
-
Nitric Oxide / metabolism*
-
Nitric Oxide / toxicity
-
Proto-Oncogene Proteins c-bcl-2 / metabolism
-
Rats
-
Rhodamines / pharmacology
-
Ruthenium Compounds / pharmacology
-
Triazenes / pharmacology
-
Tumor Cells, Cultured
-
bcl-X Protein
Substances
-
1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene
-
BCL2L1 protein, human
-
Bcl2l1 protein, rat
-
Calcium Channels
-
Calcium-Binding Proteins
-
Fluorescent Dyes
-
Ion Channels
-
Proto-Oncogene Proteins c-bcl-2
-
Rhodamines
-
Ru 360
-
Ruthenium Compounds
-
Triazenes
-
bcl-X Protein
-
mitochondrial calcium uniporter
-
tetramethylrhodamine methyl ester
-
Nitric Oxide
-
Cyclosporine
-
CASP3 protein, human
-
Casp3 protein, rat
-
Caspase 3
-
Caspases