title: Inhibition of the AIF/CypA complex protects against intrinsic death pathways induced by oxidative stress.
abstract: Delayed neuronal cell death largely contributes to the progressive infarct development and associated functional impairments after cerebral ischemia or brain trauma. Previous studies exposed a key role for the interaction of the mitochondrial protein apoptosis-inducing factor (AIF) and cytosolic cyclophilin A (CypA) in pathways of programmed cell death in neurons in vitro and in vivo. These studies suggested that pro-apoptotic activities of AIF, such as its translocation to the nucleus and subsequent DNA degradation, depend on the physical interaction of AIF with CypA. Hence, this protein complex may represent a new pharmacological target for inhibiting the lethal action of AIF on the brain tissue. In this study, we show that the AIF amino-acid residues 370-394 mediate the protein complex formation of AIF with CypA. The synthetic AIF(370-394) peptide inhibited AIF/CypA complex formation in vitro by binding CypA with a K(D) of 12 μM. Further, the peptide exerted pronounced neuroprotective effects in a model of glutamate-induced oxidative stress in cultured HT-22 cells. In this model system of AIF-dependent cell death, the AIF(370-394) peptide preserved mitochondrial integrity, as detected by measurements of the mitochondrial membrane potential and quantification of mitochondrial fragmentation. Further, the AIF(370-394) peptide inhibited perinuclear accumulation of fragmented mitochondria, mitochondrial release of AIF to the nucleus and glutamate-induced cell death to a similar extent as CypA-siRNA. These data indicate that the targeting of the AIF-CypA axis is an effective strategy of neuroprotection.
authors.affiliation: 1] Institute of Biostructures and Bioimaging (IBB)-CNR, CIRPEB, Via Mezzocannone, 16, Naples 80134, Italy [2] Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg 35032, Germany [3] Department of Neurodegeneration, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
authors.forename: N
authors.initials: N
authors.lastname: Doti
authors.affiliation: Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg 35032, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Reuther
authors.affiliation: Institute of Biostructures and Bioimaging (IBB)-CNR, CIRPEB, Via Mezzocannone, 16, Naples 80134, Italy.
authors.forename: P L
authors.initials: PL
authors.lastname: Scognamiglio
authors.affiliation: Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg 35032, Germany.
authors.forename: A M
authors.initials: AM
authors.lastname: Dolga
authors.affiliation: 1] Department of Neurodegeneration, Royal College of Surgeons in Ireland, Dublin 2, Ireland [2] Institute for Stroke and Dementia Research (ISD), University of Munich Medical School-Campus Großhadern, Max-Lebsche Platz 30, Munich D-81377, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Plesnila
authors.affiliation: Institute of Biostructures and Bioimaging (IBB)-CNR, CIRPEB, Via Mezzocannone, 16, Naples 80134, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Ruvo
authors.affiliation: Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg 35032, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Culmsee
mesh_terms: D020816:Amino Acid Motifs; D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021984:Cyclophilin A / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D006801:Humans; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism*; D018384:Oxidative Stress; D011485:Protein Binding
chemical_list: D051033:Apoptosis Inducing Factor; D021984:Cyclophilin A