title: Inhibition of the mitochondrial permeability transition by the nonimmunosuppressive cyclosporin derivative NIM811.
abstract: Cyclosporin A (CsA) shows cytoprotective properties in many cellular and in vivo models that may depend on interference of the interaction of cyclophilin A with calcineurin or of cyclophilin D with the mitochondrial permeability transition (PT) pore. The nonimmunosuppressive cyclosporin derivative N-methyl-4-valine-cyclosporin (PKF220-384) inhibits the mitochondrial permeability transition (MPT) like CsA but without calcineurin inactivation. PKF220-384 has been used to discriminate between PT pore- and calcineurin mediated effects but is no longer available. Here, we evaluated the effects of another nonimmunosuppressive cyclosporin derivative, N-methyl-4-isoleucine-cyclosporin (NIM811) on the MPT. Using two newly developed microtiter plate assays, one measuring mitochondrial swelling from absorbance and the other measuring mitochondrial membrane potential from changes in safranin fluorescence, we show that NIM811 blocks the MPT induced by calcium and inorganic phosphate, alone or in combination with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, the complex I inhibitor rotenone, and the prooxidant t-butylhydroperoxide. NIM811 was equipotent to CsA and half as potent as PKF220-384. Additionally, we show that NIM811 blocks cell killing and prevents in situ mitochondrial inner membrane permeabilization and depolarization during tumor necrosis factor-alpha-induced apoptosis to cultured rat hepatocytes. NIM811 inhibition of apoptosis was equipotent with CsA except at higher concentrations: CsA lost efficacy but NIM 811 did not. We conclude that NIM811 is a useful alternative to PKF220-384 to investigate the role of the mitochondrial permeability transition in apoptotic and necrotic cell death.
authors.affiliation: Nervous System Research, Novartis Pharma Ltd., Basel, Switzerland. peter.waldmeier@pharma.novartis.com
authors.forename: Peter C
authors.initials: PC
authors.lastname: Waldmeier
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Feldtrauer
authors.forename: Ting
authors.initials: T
authors.lastname: Qian
authors.forename: John J
authors.initials: JJ
authors.lastname: Lemasters
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D002118:Calcium / Q000494:pharmacology; D002138:Calibration; D016572:Cyclosporine / Q000737:chemistry / Q000494:pharmacology*; D004347:Drug Interactions; D007473:Ion Channels / Q000037:antagonists & inhibitors*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling / Q000187:drug effects*; D010619:Phenazines / Q000378:metabolism; D020011:Protective Agents / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012402:Rotenone / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D010619:Phenazines; D020011:Protective Agents; D014409:Tumor Necrosis Factor-alpha; D014475:Uncoupling Agents; D012402:Rotenone; D016572:Cyclosporine; C090438:(melle-4)cyclosporin; D015655:1-Methyl-4-phenylpyridinium; D002118:Calcium; C009195:safranine T