title: Apoptotic signaling activated by modulation of the F0F1-ATPase: implications for selective killing of autoimmune lymphocytes.
abstract: 7-Chloro-5-(4-hydroxyphenyl)-1-methyl-3-(napthalen-2-ylmetyl)-4,5,-dihydro-1H-benzo[b][1,4]diazepin-2(3H)-one (Bz-423) is a proapoptotic 1,4-benzodiazepine that potently suppresses disease in the murine model of lupus by selectively killing pathogenic lymphocytes. In MRL/MpJ-Fas(lpr) (MRL-lpr) mice, Bz-423 overcomes deficient expression of the Fas death receptor and hyperactivation of antiapoptotic phosphatidylinositol 3-kinase (PI3K)-Akt signaling to specifically kill pathogenic CD4(+) T cells. Bz-423 binds to the oligomycin-sensitivity-conferring protein component of the mitochondrial F(0)F(1)-ATPase, which modulates the enzyme leading to formation of superoxide by the mitochondrial respiratory chain. Scavenging this reactive oxygen species blocks all subsequent components of the apoptotic cascade. To gain insight into how apoptotic signaling activated by Bz-423-induced superoxide contributes to the selective depletion of MRL-lpr CD4(+) T cells, we characterized the death mechanism in a CD4(+) T cell leukemia line (Jurkat). Although Bz-423-induced superoxide indirectly inactivates Akt, this response is not required for T cell death. Apoptosis instead results from parallel increases in levels of the proapoptotic Bcl-2 proteins Noxa and Bak leading to specific activation of Bak, mitochondrial outer membrane permeabilization, and a commitment to apoptosis. By directly up-regulating proteins that trigger loss of mitochondrial outer membrane integrity, Bz-423 bypasses defective Fas function and antiapoptotic PI3K-Akt signaling in MRL-lpr CD4(+) T cells. Moreover, because disease-associated abnormalities should sensitize autoreactive CD4(+) T cells to transcriptional up-regulation of Noxa by redox signals and to Bak-dependent apoptosis, the apoptotic mechanism elucidated in Jurkat cells provides important clues into the cell-type- and disease-selective effects of Bz-423 in MRL-lpr mice.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Sundberg
authors.forename: Lara
authors.initials: L
authors.lastname: Swenson
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Wahl
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Opipari
authors.forename: Gary D
authors.initials: GD
authors.lastname: Glick
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015551:Autoimmunity / Q000276:immunology*; D001569:Benzodiazepines / Q000494:pharmacology*; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D019169:Jurkat Cells; D008214:Lymphocytes / Q000276:immunology*; D048670:MAP Kinase Kinase 4 / Q000235:genetics; D051379:Mice; D008856:Microscopy, Fluorescence; D051058:Oncogene Protein v-akt / Q000235:genetics; D006180:Proton-Translocating ATPases / Q000502:physiology*; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D050998:bcl-2 Homologous Antagonist-Killer Protein; D001569:Benzodiazepines; D000255:Adenosine Triphosphate; D004247:DNA; D051058:Oncogene Protein v-akt; D048670:MAP Kinase Kinase 4; D006180:Proton-Translocating ATPases; C468549:Bz-423
references.citation: Curr Opin Cell Biol. 2007 Apr;19(2):142-9
references.pmid: 17303404
references.citation: Genes Dev. 2005 Jun 1;19(11):1294-305
references.pmid: 15901672
references.citation: Arthritis Rheum. 2009 Jan;60(1):207-18
references.pmid: 19116915
references.citation: J Clin Invest. 2002 Oct;110(8):1123-32
references.pmid: 12393848
references.citation: Proc Natl Acad Sci U S A. 2001 Nov 20;98(24):13681-6
references.pmid: 11717429
references.citation: Science. 2004 Apr 23;304(5670):554
references.pmid: 15016963
references.citation: J Inorg Biochem. 2001 Jun;85(2-3):201-8
references.pmid: 11410240
references.citation: Clin Immunol. 2004 Oct;113(1):4-13
references.pmid: 15380523
references.citation: Neuropharmacology. 2007 Feb;52(2):536-41
references.pmid: 17027047
references.citation: Proc Natl Acad Sci U S A. 1994 May 24;91(11):4708-12
references.pmid: 8197123
references.citation: Immunol Rev. 2005 Jun;205:158-69
references.pmid: 15882352
references.citation: Oncogene. 2005 Jun 2;24(24):3954-63
references.pmid: 15782121
references.citation: Oncogene. 2005 May 26;24(23):3797-809
references.pmid: 15782127
references.citation: J Biol Chem. 2008 Feb 8;283(6):3357-3364
references.pmid: 18056701
references.citation: Nat Med. 2005 Sep;11(9):933-5
references.pmid: 16127435
references.citation: Biochem Pharmacol. 2009 Oct 15;78(8):966-73
references.pmid: 19481066
references.citation: Free Radic Biol Med. 2008 Nov 1;45(9):1232-42
references.pmid: 18718527
references.citation: Mol Cell. 2006 Mar 17;21(6):749-60
references.pmid: 16543145
references.citation: Arthritis Rheum. 2003 Mar;48(3):757-66
references.pmid: 12632430
references.citation: Science. 2007 Feb 9;315(5813):856-9
references.pmid: 17289999
references.citation: Biochim Biophys Acta. 2004 Mar 11;1697(1-2):3-16
references.pmid: 15023346
references.citation: Blood. 2006 Dec 15;108(13):3967-75
references.pmid: 16926289
references.citation: Science. 2006 Feb 10;311(5762):847-51
references.pmid: 16469926
references.citation: Autoimmun Rev. 2004 Jan;3(1):33-9
references.pmid: 14871647
references.citation: Nat Rev Mol Cell Biol. 2008 Jan;9(1):47-59
references.pmid: 18097445
references.citation: Oncogene. 2006 Nov 16;25(54):7192-200
references.pmid: 16732318
references.citation: Carcinogenesis. 2009 Sep;30(9):1517-27
references.pmid: 19578044
references.citation: Microbiol Mol Biol Rev. 2008 Dec;72(4):590-641, Table of Contents
references.pmid: 19052322
references.citation: Cell Death Differ. 2007 Mar;14(3):534-47
references.pmid: 16888645
references.citation: Proc Natl Acad Sci U S A. 2008 Feb 26;105(8):3035-40
references.pmid: 18287039
references.citation: Cell Death Differ. 2003 Jan;10(1):36-44
references.pmid: 12655294
references.citation: J Immunol. 1997 Nov 1;159(9):4197-204
references.pmid: 9379013
references.citation: Trends Immunol. 2001 Sep;22(9):490-6
references.pmid: 11525939
references.citation: Nat Rev Immunol. 2007 Mar;7(3):191-201
references.pmid: 17290298
references.citation: Curr Mol Med. 2008 Mar;8(2):138-47
references.pmid: 18336294
references.citation: Mol Cell Endocrinol. 2008 Jan 16;281(1-2):47-55
references.pmid: 18035477
references.citation: Cell. 2004 Jan 23;116(2):205-19
references.pmid: 14744432
references.citation: Arch Biochem Biophys. 1999 Mar 1;363(1):91-7
references.pmid: 10049502
references.citation: EMBO J. 2007 Feb 7;26(3):825-34
references.pmid: 17235284
references.citation: Chem Biol. 2005 Apr;12(4):485-96
references.pmid: 15850986