Bax Channel Inhibitors Prevent Mitochondrion-mediated Apoptosis and Protect Neurons in a Model of Global Brain Ischemia

• Published in: The Journal of biological chemistry Vol. 280; no. 52; pp. 42960 - 42970
• Main Authors: Hetz, Claudio, Vitte, Pierre-Alain, Bombrun, Agnes, Rostovtseva, Tatiana K., Montessuit, Sylvie, Hiver, Agnes, Schwarz, Matthias K., Church, Dennis J., Korsmeyer, Stanley J., Martinou, Jean-Claude, Antonsson, Bruno
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30.12.2005; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; Apoptosis; bcl-2-Associated X Protein - metabolism; Brain - pathology; Cell Death; Cell Line; Cell Separation; Cytochromes c - metabolism; Dose-Response Relationship, Drug; Electrophysiology; Flow Cytometry; Gerbillinae; HeLa Cells; Hippocampus - metabolism; Humans; Ischemia - pathology; Lipids - chemistry; Liposomes - chemistry; Liposomes - metabolism; Mice; Mitochondria - metabolism; Mitochondria - pathology; Models, Chemical; Neurons - metabolism; Protein Conformation; Protein Structure, Quaternary; Recombinant Proteins - chemistry; Reperfusion; Time Factors
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M505843200

Ischemic injuries are associated with several pathological conditions, including stroke and myocardial infarction. Several studies have indicated extensive apoptotic cell death in the infarcted area as well as in the penumbra region of the infarcted tissue. Studies with transgenic animals suggest that the mitochondrion-mediated apoptosis pathway is involved in ischemia-related cell death. This pathway is triggered by activation of pro-apoptotic Bcl-2 family members such as Bax. Here, we have identified and synthesized two low molecular weight compounds that block Bax channel activity. The Bax channel inhibitors prevented cytochrome c release from mitochondria, inhibited the decrease in the mitochondrial membrane potential, and protected cells against apoptosis. The Bax channel inhibitors did not affect the conformational activation of Bax or its translocation and insertion into the mitochondrial membrane in cells undergoing apoptosis. Furthermore, the compounds protected neurons in an animal model of global brain ischemia. The protective effect in the animal model correlated with decreased cytochrome c release in the infarcted area. This is the first demonstration that Bax channel activity is required in apoptosis.