The Experts below are selected from a list of 1398 Experts worldwide ranked by ideXlab platform

Catherine Brenner - One of the best experts on this subject based on the ideXlab platform.

  • Control of Mitochondrial Membrane Permeabilization by Adenine Nucleotide Translocator Interacting with HIV-1 Viral Protein R and Bcl-2
    2013
    Co-Authors: Etienne Jacotot, Helena L A Vieira, Sabine Druillennec, Johan Hoebeke, Chahrazed El Hamel, Catherine Brenner, Maurice Geuskens, Karine F Ferri, Markus Loeffler, Anne-sophie Belzacq
    Abstract:

    Viral protein R (Vpr), an apoptogenic accessory protein encoded by HIV-1, induces mitochondrial membrane permeabilization (MMP) via a specific interaction with the permeability transition pore complex, which comprises the voltage-dependent anion channel (VDAC) in the outer membrane (OM) and the Adenine Nucleotide Translocator (ANT) in the inner membrane. Here, we demonstrate that a synthetic Vpr-derived peptide (Vpr52-96) specifically binds to the intermembrane face of the ANT with an affinity in the nanomolar range. Taking advantage of this specific interaction, we determined the role of ANT in the control of MMP. In planar lipid bilayers, Vpr52-96 and purified ANT cooperatively form large conductance channels. This cooperative channel formation relies on a direct protein–protein interaction since it is abolished by the addition of a peptide corresponding to the Vpr binding site of ANT. Whe

  • inhibition of Adenine Nucleotide Translocator pore function and protection against apoptosis in vivo by an hiv protease inhibitor
    2005
    Co-Authors: Joel G R Weaver, Catherine Brenner, Agathe Tarze, Tia C Moffat, Morgane Lebras, Aurelien Deniaud, Gary D Bren, Mario Y Morin, Barbara N Phenix, Li Dong
    Abstract:

    Inhibitors of HIV protease have been shown to have antiapoptotic effects in vitro, yet whether these effects are seen in vivo remains controversial. In this study, we have evaluated the impact of the HIV protease inhibitor (PI) nelfinavir, boosted with ritonavir, in models of nonviral disease associated with excessive apoptosis. In mice with Fas-induced fatal hepatitis, Staphylococcal enterotoxin B-induced shock, and middle cerebral artery occlusion-induced stroke, we demonstrate that PIs significantly reduce apoptosis and improve histology, function, and/or behavioral recovery in each of these models. Further, we demonstrate that both in vitro and in vivo, PIs block apoptosis through the preservation of mitochondrial integrity and that in vitro PIs act to prevent pore function of the Adenine Nucleotide Translocator (ANT) subunit of the mitochondrial permeability transition pore complex.

  • the Adenine Nucleotide Translocator a new potential chemotherapeutic target
    2003
    Co-Authors: Anne-sophie Belzacq, Catherine Brenner
    Abstract:

    Identification of new targets is of utmost importance for the development of efficient apoptosis-modulating drugs. This has become possible from the unraveling of the basic apoptosis mechanisms and notably, from the demonstration of the mitochondrial membrane permeabilization as a central rate-limiting step of numerous models of cell death. Indeed, molecular and pharmacological studies revealed that the Adenine Nucleotide Translocator (ANT) could be a therapeutic target. First, ANT is a bi-functional protein. It mediates the exchange of cytosolic ADP and mitochondrial ATP, and contributes to apoptosis via its capacity to become a lethal pore. Second, both ANT functions are under the control of the (anti)-oncogenes from the Bax/Bcl-2 family, and third, agents as diverse as proteins, lipids, ions, pro-oxidants or chemotherapeutic agents directly modulate the pore-forming activity of ANT. Here, we will review the mode of apoptosis induction by various classes of chemotherapeutic agents, which all influence directly ANT pro-apoptotic function. Hopefully, this will yield several clues to the modulation of apoptosis from a therapeutic perspective.

  • the Adenine Nucleotide Translocator in apoptosis
    2002
    Co-Authors: Anne-sophie Belzacq, Helena L A Vieira, Guido Kroemer, Catherine Brenner
    Abstract:

    Alteration of mitochondrial membrane permeability is a central mechanism leading invariably to cell death, which results, at least in part, from the opening of the permeability transition pore complex (PTPC). Indeed, extended PTPC opening is sufficient to trigger an increase in mitochondrial membrane permeability and apoptosis. Among the various PTPC components, the Adenine Nucleotide Translocator (ANT) appears to act as a bi-functional protein which, on the one hand, contributes to a crucial step of aerobic energy metabolism, the ADP/ATP translocation, and on the other hand, can be converted into a pro-apoptotic pore under the control of onco- and anti-oncoproteins from the Bax/Bcl-2 family. In this review, we will discuss recent advances in the cooperation between ANT and Bax/Bcl-2 family members, the multiplicity of agents affecting ANT pore function and the putative role of ANT isoforms in apoptosis control.

  • Adenine Nucleotide Translocator mediates the mitochondrial membrane permeabilization induced by lonidamine, arsenite and CD437
    2001
    Co-Authors: Anne-sophie Belzacq, Philippe Marchetti, Helena L A Vieira, Catherine Brenner, Didier Metivier, Isabel Cohen, Chahrazed El Hamel, Delphine Haouzi, Guido Kroemer
    Abstract:

    An increasing number of experimental chemotherapeutic agents induce apoptosis by directly triggering mitochondrial membrane permeabilization (MMP). Here we examined MMP induced by lonidamine, arsenite, and the retinoid derivative CD437. Cells overexpressing the cytomegalovirus-encoded protein vMIA, a protein which interacts with the Adenine Nucleotide Translocator, were strongly protected against the MMP-inducing and apoptogenic effects of lonidamine, arsenite, and CD437. In a cell-free system, lonidamine, arsenite, and CD437 induced the permeabilization of ANT proteoliposomes, yet had no effect on protein-free liposomes. The ANT-dependent membrane permeabilization was inhibited by the two ANT ligands ATP and ADP, as well as by recombinant Bcl-2 protein. Lonidamine, arsenite, and CD437, added to synthetic planar lipid bilayers containing ANT, elicited ANT channel activities with clearly distinct conductance levels of 20±7, 100±30, and 47±7 pS, respectively. Altering the ATP/ADP gradient built up on the inner mitochondrial membrane by inhibition of glycolysis and/or oxidative phosphorylation differentially modulated the cytocidal potential of lonidamine, arsenite, and CD437. Inhibition of F_0F_1ATPase without glycolysis inhibition sensitized to lonidamine-induced cell death. In contrast, only the combined inhibition of glycolysis plus F_0F_1ATPase sensitized to arsenite-induced cell death. No sensitization to cell death induction by CD437 was achieved by glucose depletion and/or oligomycin addition. These results indicate that ANT is a target of lonidamine, arsenite, and CD437 and unravel an unexpected heterogeneity in the mode of action of these three compounds.

Anne-sophie Belzacq - One of the best experts on this subject based on the ideXlab platform.

  • Control of Mitochondrial Membrane Permeabilization by Adenine Nucleotide Translocator Interacting with HIV-1 Viral Protein R and Bcl-2
    2013
    Co-Authors: Etienne Jacotot, Helena L A Vieira, Sabine Druillennec, Johan Hoebeke, Chahrazed El Hamel, Catherine Brenner, Maurice Geuskens, Karine F Ferri, Markus Loeffler, Anne-sophie Belzacq
    Abstract:

    Viral protein R (Vpr), an apoptogenic accessory protein encoded by HIV-1, induces mitochondrial membrane permeabilization (MMP) via a specific interaction with the permeability transition pore complex, which comprises the voltage-dependent anion channel (VDAC) in the outer membrane (OM) and the Adenine Nucleotide Translocator (ANT) in the inner membrane. Here, we demonstrate that a synthetic Vpr-derived peptide (Vpr52-96) specifically binds to the intermembrane face of the ANT with an affinity in the nanomolar range. Taking advantage of this specific interaction, we determined the role of ANT in the control of MMP. In planar lipid bilayers, Vpr52-96 and purified ANT cooperatively form large conductance channels. This cooperative channel formation relies on a direct protein–protein interaction since it is abolished by the addition of a peptide corresponding to the Vpr binding site of ANT. Whe

  • the Adenine Nucleotide Translocator a new potential chemotherapeutic target
    2003
    Co-Authors: Anne-sophie Belzacq, Catherine Brenner
    Abstract:

    Identification of new targets is of utmost importance for the development of efficient apoptosis-modulating drugs. This has become possible from the unraveling of the basic apoptosis mechanisms and notably, from the demonstration of the mitochondrial membrane permeabilization as a central rate-limiting step of numerous models of cell death. Indeed, molecular and pharmacological studies revealed that the Adenine Nucleotide Translocator (ANT) could be a therapeutic target. First, ANT is a bi-functional protein. It mediates the exchange of cytosolic ADP and mitochondrial ATP, and contributes to apoptosis via its capacity to become a lethal pore. Second, both ANT functions are under the control of the (anti)-oncogenes from the Bax/Bcl-2 family, and third, agents as diverse as proteins, lipids, ions, pro-oxidants or chemotherapeutic agents directly modulate the pore-forming activity of ANT. Here, we will review the mode of apoptosis induction by various classes of chemotherapeutic agents, which all influence directly ANT pro-apoptotic function. Hopefully, this will yield several clues to the modulation of apoptosis from a therapeutic perspective.

  • the Adenine Nucleotide Translocator in apoptosis
    2002
    Co-Authors: Anne-sophie Belzacq, Helena L A Vieira, Guido Kroemer, Catherine Brenner
    Abstract:

    Alteration of mitochondrial membrane permeability is a central mechanism leading invariably to cell death, which results, at least in part, from the opening of the permeability transition pore complex (PTPC). Indeed, extended PTPC opening is sufficient to trigger an increase in mitochondrial membrane permeability and apoptosis. Among the various PTPC components, the Adenine Nucleotide Translocator (ANT) appears to act as a bi-functional protein which, on the one hand, contributes to a crucial step of aerobic energy metabolism, the ADP/ATP translocation, and on the other hand, can be converted into a pro-apoptotic pore under the control of onco- and anti-oncoproteins from the Bax/Bcl-2 family. In this review, we will discuss recent advances in the cooperation between ANT and Bax/Bcl-2 family members, the multiplicity of agents affecting ANT pore function and the putative role of ANT isoforms in apoptosis control.

  • Adenine Nucleotide Translocator mediates the mitochondrial membrane permeabilization induced by lonidamine, arsenite and CD437
    2001
    Co-Authors: Anne-sophie Belzacq, Philippe Marchetti, Helena L A Vieira, Catherine Brenner, Didier Metivier, Isabel Cohen, Chahrazed El Hamel, Delphine Haouzi, Guido Kroemer
    Abstract:

    An increasing number of experimental chemotherapeutic agents induce apoptosis by directly triggering mitochondrial membrane permeabilization (MMP). Here we examined MMP induced by lonidamine, arsenite, and the retinoid derivative CD437. Cells overexpressing the cytomegalovirus-encoded protein vMIA, a protein which interacts with the Adenine Nucleotide Translocator, were strongly protected against the MMP-inducing and apoptogenic effects of lonidamine, arsenite, and CD437. In a cell-free system, lonidamine, arsenite, and CD437 induced the permeabilization of ANT proteoliposomes, yet had no effect on protein-free liposomes. The ANT-dependent membrane permeabilization was inhibited by the two ANT ligands ATP and ADP, as well as by recombinant Bcl-2 protein. Lonidamine, arsenite, and CD437, added to synthetic planar lipid bilayers containing ANT, elicited ANT channel activities with clearly distinct conductance levels of 20±7, 100±30, and 47±7 pS, respectively. Altering the ATP/ADP gradient built up on the inner mitochondrial membrane by inhibition of glycolysis and/or oxidative phosphorylation differentially modulated the cytocidal potential of lonidamine, arsenite, and CD437. Inhibition of F_0F_1ATPase without glycolysis inhibition sensitized to lonidamine-induced cell death. In contrast, only the combined inhibition of glycolysis plus F_0F_1ATPase sensitized to arsenite-induced cell death. No sensitization to cell death induction by CD437 was achieved by glucose depletion and/or oligomycin addition. These results indicate that ANT is a target of lonidamine, arsenite, and CD437 and unravel an unexpected heterogeneity in the mode of action of these three compounds.

  • The Adenine Nucleotide Translocator: a target of nitric oxide, peroxynitrite, and 4-hydroxynonenal
    2001
    Co-Authors: Helena L A Vieira, Anne-sophie Belzacq, Francesca Bernassola, Isabel Cohen, Etienne Jacotot, Karine F Ferri, Chahrazed El Hamel, Laura M Bartle, Delphine Haouzi, Gerry Melino
    Abstract:

    Nitric oxide (NO), peroxynitrite, and 4-hydroxynonenal (HNE) may be involved in the pathological demise of cells via apoptosis. Apoptosis induced by these agents is inhibited by Bcl-2, suggesting the involvement of mitochondria in the death pathway. In vitro , NO, peroxynitrite and HNE can cause direct permeabilization of mitochondrial membranes, and this effect is inhibited by cyclosporin A, indicating involvement of the permeability transition pore complex (PTPC) in the permeabilization event. NO, peroxynitrite and HNE also permeabilize proteoliposomes containing the Adenine Nucleotide Translocator (ANT), one of the key components of the PTPC, yet have no or little effects on protein-free control liposomes. ANT-dependent, NO-, peroxynitrite- or HNE-induced permeabilization is at least partially inhibited by recombinant Bcl-2 protein, as well as the antioxidants trolox and butylated hydroxytoluene. In vitro , none of the tested agents (NO, peroxynitrite, HNE, and tert -butylhydroperoxide) causes preferential carbonylation HNE adduction, or nitrotyrosylation of ANT. However, all these agents induced ANT to undergo thiol oxidation/derivatization. Peroxynitrite and HNE also caused significant lipid peroxidation, which was antagonized by butylated hydroxytoluene but not by recombinant Bcl-2. Transfection-enforced expression of vMIA, a viral apoptosis inhibitor specifically targeted to ANT, largely reduces the mitochondrial and nuclear signs of apoptosis induced by NO, peroxynitrite and HNE in intact cells. Taken together these data suggest that NO, peroxynitrite, and HNE may directly act on ANT to induce mitochondrial membrane permeabilization and apoptosis.

Helena L A Vieira - One of the best experts on this subject based on the ideXlab platform.

  • Control of Mitochondrial Membrane Permeabilization by Adenine Nucleotide Translocator Interacting with HIV-1 Viral Protein R and Bcl-2
    2013
    Co-Authors: Etienne Jacotot, Helena L A Vieira, Sabine Druillennec, Johan Hoebeke, Chahrazed El Hamel, Catherine Brenner, Maurice Geuskens, Karine F Ferri, Markus Loeffler, Anne-sophie Belzacq
    Abstract:

    Viral protein R (Vpr), an apoptogenic accessory protein encoded by HIV-1, induces mitochondrial membrane permeabilization (MMP) via a specific interaction with the permeability transition pore complex, which comprises the voltage-dependent anion channel (VDAC) in the outer membrane (OM) and the Adenine Nucleotide Translocator (ANT) in the inner membrane. Here, we demonstrate that a synthetic Vpr-derived peptide (Vpr52-96) specifically binds to the intermembrane face of the ANT with an affinity in the nanomolar range. Taking advantage of this specific interaction, we determined the role of ANT in the control of MMP. In planar lipid bilayers, Vpr52-96 and purified ANT cooperatively form large conductance channels. This cooperative channel formation relies on a direct protein–protein interaction since it is abolished by the addition of a peptide corresponding to the Vpr binding site of ANT. Whe

  • the Adenine Nucleotide Translocator in apoptosis
    2002
    Co-Authors: Anne-sophie Belzacq, Helena L A Vieira, Guido Kroemer, Catherine Brenner
    Abstract:

    Alteration of mitochondrial membrane permeability is a central mechanism leading invariably to cell death, which results, at least in part, from the opening of the permeability transition pore complex (PTPC). Indeed, extended PTPC opening is sufficient to trigger an increase in mitochondrial membrane permeability and apoptosis. Among the various PTPC components, the Adenine Nucleotide Translocator (ANT) appears to act as a bi-functional protein which, on the one hand, contributes to a crucial step of aerobic energy metabolism, the ADP/ATP translocation, and on the other hand, can be converted into a pro-apoptotic pore under the control of onco- and anti-oncoproteins from the Bax/Bcl-2 family. In this review, we will discuss recent advances in the cooperation between ANT and Bax/Bcl-2 family members, the multiplicity of agents affecting ANT pore function and the putative role of ANT isoforms in apoptosis control.

  • Adenine Nucleotide Translocator mediates the mitochondrial membrane permeabilization induced by lonidamine, arsenite and CD437
    2001
    Co-Authors: Anne-sophie Belzacq, Philippe Marchetti, Helena L A Vieira, Catherine Brenner, Didier Metivier, Isabel Cohen, Chahrazed El Hamel, Delphine Haouzi, Guido Kroemer
    Abstract:

    An increasing number of experimental chemotherapeutic agents induce apoptosis by directly triggering mitochondrial membrane permeabilization (MMP). Here we examined MMP induced by lonidamine, arsenite, and the retinoid derivative CD437. Cells overexpressing the cytomegalovirus-encoded protein vMIA, a protein which interacts with the Adenine Nucleotide Translocator, were strongly protected against the MMP-inducing and apoptogenic effects of lonidamine, arsenite, and CD437. In a cell-free system, lonidamine, arsenite, and CD437 induced the permeabilization of ANT proteoliposomes, yet had no effect on protein-free liposomes. The ANT-dependent membrane permeabilization was inhibited by the two ANT ligands ATP and ADP, as well as by recombinant Bcl-2 protein. Lonidamine, arsenite, and CD437, added to synthetic planar lipid bilayers containing ANT, elicited ANT channel activities with clearly distinct conductance levels of 20±7, 100±30, and 47±7 pS, respectively. Altering the ATP/ADP gradient built up on the inner mitochondrial membrane by inhibition of glycolysis and/or oxidative phosphorylation differentially modulated the cytocidal potential of lonidamine, arsenite, and CD437. Inhibition of F_0F_1ATPase without glycolysis inhibition sensitized to lonidamine-induced cell death. In contrast, only the combined inhibition of glycolysis plus F_0F_1ATPase sensitized to arsenite-induced cell death. No sensitization to cell death induction by CD437 was achieved by glucose depletion and/or oligomycin addition. These results indicate that ANT is a target of lonidamine, arsenite, and CD437 and unravel an unexpected heterogeneity in the mode of action of these three compounds.

  • The Adenine Nucleotide Translocator: a target of nitric oxide, peroxynitrite, and 4-hydroxynonenal
    2001
    Co-Authors: Helena L A Vieira, Anne-sophie Belzacq, Francesca Bernassola, Isabel Cohen, Etienne Jacotot, Karine F Ferri, Chahrazed El Hamel, Laura M Bartle, Delphine Haouzi, Gerry Melino
    Abstract:

    Nitric oxide (NO), peroxynitrite, and 4-hydroxynonenal (HNE) may be involved in the pathological demise of cells via apoptosis. Apoptosis induced by these agents is inhibited by Bcl-2, suggesting the involvement of mitochondria in the death pathway. In vitro , NO, peroxynitrite and HNE can cause direct permeabilization of mitochondrial membranes, and this effect is inhibited by cyclosporin A, indicating involvement of the permeability transition pore complex (PTPC) in the permeabilization event. NO, peroxynitrite and HNE also permeabilize proteoliposomes containing the Adenine Nucleotide Translocator (ANT), one of the key components of the PTPC, yet have no or little effects on protein-free control liposomes. ANT-dependent, NO-, peroxynitrite- or HNE-induced permeabilization is at least partially inhibited by recombinant Bcl-2 protein, as well as the antioxidants trolox and butylated hydroxytoluene. In vitro , none of the tested agents (NO, peroxynitrite, HNE, and tert -butylhydroperoxide) causes preferential carbonylation HNE adduction, or nitrotyrosylation of ANT. However, all these agents induced ANT to undergo thiol oxidation/derivatization. Peroxynitrite and HNE also caused significant lipid peroxidation, which was antagonized by butylated hydroxytoluene but not by recombinant Bcl-2. Transfection-enforced expression of vMIA, a viral apoptosis inhibitor specifically targeted to ANT, largely reduces the mitochondrial and nuclear signs of apoptosis induced by NO, peroxynitrite and HNE in intact cells. Taken together these data suggest that NO, peroxynitrite, and HNE may directly act on ANT to induce mitochondrial membrane permeabilization and apoptosis.

  • apoptosis induction by the photosensitizer verteporfin identification of mitochondrial Adenine Nucleotide Translocator as a critical target
    2001
    Co-Authors: Anne-sophie Belzacq, Helena L A Vieira, Etienne Jacotot, Guido Kroemer, John C Reed, Dominique Mistro, David J Granville, Zhihua Xie, Catherine Brenner
    Abstract:

    We report that the photosensitizer verteporfin kills lymphoma cells by an apoptotic process involving a dissipation of the mitochondrial inner transmembrane potential (deltapsim). Light-activated verteporfin-induced apoptosis was abolished by transfection with Bcl-2, a procedure reported to inhibit the mitochondrial permeability transition pore complex (PTPC). Verteporfin triggered the deltapsim loss in isolated mitochondria in vitro, and this effect was suppressed by bongrekic acid and cyclosporin A. Verteporfin plus light also permeabilized proteoliposomes containing the semipurified PTPC or the purified PTPC component Adenine Nucleotide Translocator (ANT), yet had no effect on protein-free control liposomes. Verteporfin phototoxicity on ANT proteoliposomes was mediated by reactive oxygen species and was prevented by recombinant Bcl-2 or the Adenine Nucleotides ATP and ADP. In conclusion, verteporfin belongs to a class of clinically used chemotherapeutic agents acting on PTPC and ANT.

Guido Kroemer - One of the best experts on this subject based on the ideXlab platform.

  • the Adenine Nucleotide Translocator in apoptosis
    2002
    Co-Authors: Anne-sophie Belzacq, Helena L A Vieira, Guido Kroemer, Catherine Brenner
    Abstract:

    Alteration of mitochondrial membrane permeability is a central mechanism leading invariably to cell death, which results, at least in part, from the opening of the permeability transition pore complex (PTPC). Indeed, extended PTPC opening is sufficient to trigger an increase in mitochondrial membrane permeability and apoptosis. Among the various PTPC components, the Adenine Nucleotide Translocator (ANT) appears to act as a bi-functional protein which, on the one hand, contributes to a crucial step of aerobic energy metabolism, the ADP/ATP translocation, and on the other hand, can be converted into a pro-apoptotic pore under the control of onco- and anti-oncoproteins from the Bax/Bcl-2 family. In this review, we will discuss recent advances in the cooperation between ANT and Bax/Bcl-2 family members, the multiplicity of agents affecting ANT pore function and the putative role of ANT isoforms in apoptosis control.

  • Adenine Nucleotide Translocator mediates the mitochondrial membrane permeabilization induced by lonidamine, arsenite and CD437
    2001
    Co-Authors: Anne-sophie Belzacq, Philippe Marchetti, Helena L A Vieira, Catherine Brenner, Didier Metivier, Isabel Cohen, Chahrazed El Hamel, Delphine Haouzi, Guido Kroemer
    Abstract:

    An increasing number of experimental chemotherapeutic agents induce apoptosis by directly triggering mitochondrial membrane permeabilization (MMP). Here we examined MMP induced by lonidamine, arsenite, and the retinoid derivative CD437. Cells overexpressing the cytomegalovirus-encoded protein vMIA, a protein which interacts with the Adenine Nucleotide Translocator, were strongly protected against the MMP-inducing and apoptogenic effects of lonidamine, arsenite, and CD437. In a cell-free system, lonidamine, arsenite, and CD437 induced the permeabilization of ANT proteoliposomes, yet had no effect on protein-free liposomes. The ANT-dependent membrane permeabilization was inhibited by the two ANT ligands ATP and ADP, as well as by recombinant Bcl-2 protein. Lonidamine, arsenite, and CD437, added to synthetic planar lipid bilayers containing ANT, elicited ANT channel activities with clearly distinct conductance levels of 20±7, 100±30, and 47±7 pS, respectively. Altering the ATP/ADP gradient built up on the inner mitochondrial membrane by inhibition of glycolysis and/or oxidative phosphorylation differentially modulated the cytocidal potential of lonidamine, arsenite, and CD437. Inhibition of F_0F_1ATPase without glycolysis inhibition sensitized to lonidamine-induced cell death. In contrast, only the combined inhibition of glycolysis plus F_0F_1ATPase sensitized to arsenite-induced cell death. No sensitization to cell death induction by CD437 was achieved by glucose depletion and/or oligomycin addition. These results indicate that ANT is a target of lonidamine, arsenite, and CD437 and unravel an unexpected heterogeneity in the mode of action of these three compounds.

  • apoptosis induction by the photosensitizer verteporfin identification of mitochondrial Adenine Nucleotide Translocator as a critical target
    2001
    Co-Authors: Anne-sophie Belzacq, Helena L A Vieira, Etienne Jacotot, Guido Kroemer, John C Reed, Dominique Mistro, David J Granville, Zhihua Xie, Catherine Brenner
    Abstract:

    We report that the photosensitizer verteporfin kills lymphoma cells by an apoptotic process involving a dissipation of the mitochondrial inner transmembrane potential (deltapsim). Light-activated verteporfin-induced apoptosis was abolished by transfection with Bcl-2, a procedure reported to inhibit the mitochondrial permeability transition pore complex (PTPC). Verteporfin triggered the deltapsim loss in isolated mitochondria in vitro, and this effect was suppressed by bongrekic acid and cyclosporin A. Verteporfin plus light also permeabilized proteoliposomes containing the semipurified PTPC or the purified PTPC component Adenine Nucleotide Translocator (ANT), yet had no effect on protein-free control liposomes. Verteporfin phototoxicity on ANT proteoliposomes was mediated by reactive oxygen species and was prevented by recombinant Bcl-2 or the Adenine Nucleotides ATP and ADP. In conclusion, verteporfin belongs to a class of clinically used chemotherapeutic agents acting on PTPC and ANT.

  • bcl 2 and bax regulate the channel activity of the mitochondrial Adenine Nucleotide Translocator
    2000
    Co-Authors: Catherine Brenner, Helena L A Vieira, Isabel Marzo, Naoufal Zamzami, John C Reed, Herve Cadiou, Brian Leber, David W Andrews, H Duclohier, Guido Kroemer
    Abstract:

    Bcl-2 family protein including anti-apoptotic (Bcl-2) or pro-apoptotic (Bax) members can form ion channels when incorporated into synthetic lipid bilayers. This contrasts with the observation that Bcl-2 stabilizes the mitochondrial membrane barrier function and inhibits the permeability transition pore complex (PTPC). Here we provide experimental data which may explain this apparent paradox. Bax and Adenine Nucleotide Translocator (ANT), the most abundant inner mitochondrial membrane protein, can interact in artificial lipid bilayers to yield an efficient composite channel whose electrophysiological properties differ quantitatively and qualitatively from the channels formed by Bax or ANT alone. The formation of this composite channel can be observed in conditions in which Bax protein alone has no detectable channel activity. Cooperative channel formation by Bax and ANT is stimulated by the ANT ligand atractyloside (Atr) but inhibited by ATP, indicating that it depends on the conformation of ANT. In contrast to the combination of Bax and ANT, ANT does not form active channels when incorporated into membranes with Bcl-2. Rather, ANT and Bcl-2 exhibit mutual inhibition of channel formation. Bcl-2 prevents channel formation by Atr-treated ANT and neutralizes the cooperation between Bax and ANT. Our data are compatible with a menage a trois model of mitochondrial apoptosis regulation in which ANT, the likely pore forming protein within the PTPC, interacts with Bax or Bcl-2 which influence its pore forming potential in opposing manners.

  • oxidation of a critical thiol residue of the Adenine Nucleotide Translocator enforces bcl 2 independent permeability transition pore opening and apoptosis
    2000
    Co-Authors: Paola Costantini, Helena L A Vieira, Catherine Brenner, Anne-sophie Belzacq, Naoufal Zamzami, Santos A Susin, Nathanael Larochette, M De Pablo, Guido Kroemer
    Abstract:

    : Mitochondrial membrane permeabilization is a critical event in the process leading to physiological or chemotherapy-induced apoptosis. This permeabilization event is at least in part under the control of the permeability transition pore complex (PTPC), which interacts with oncoproteins from the Bcl-2 family as well as with tumor suppressor proteins from the Bax family, which inhibit or facilitate membrane permeabilization, respectively. Here we show that thiol crosslinking agents including diazenedicarboxylic acid bis 5N, N-dimethylamide (diamide), dithiodipyridine (DTDP), or bis-maleimido-hexane (BMH) can act on the Adenine Nucleotide Translocator (ANT), one of the proteins within the PTPC. ANT alone reconstituted into artificial lipid bilayers suffices to confer a membrane permeabilization response to thiol crosslinking agents. Diamide, DTDP, and BMH but not tert-butylhydroperoxide or arsenite cause the oxidation of a critical cysteine residue (Cys 56) of ANT. Thiol modification within ANT is observed in intact cells, isolated mitochondria, and purified ANT. Recombinant Bcl-2 fails to prevent thiol modification of ANT. Concomitantly, a series of different thiol crosslinking agents (diamide, DTDP, and BMH, phenylarsine oxide) but not tert-butylhydroperoxide or arsenite induce mitochondrial membrane permeabilization and cell death irrespective of the expression level of Bcl-2. These data indicate that thiol crosslinkers cause a covalent modification of ANT which, beyond any control by Bcl-2, leads to mitochondrial membrane permeabilization and cell death.

Douglas C Wallace - One of the best experts on this subject based on the ideXlab platform.

  • adeno associated virus mediated gene transfer of the heart muscle Adenine Nucleotide Translocator ant in mouse
    2005
    Co-Authors: Adrian Flierl, Douglas C Wallace, Y Chen, Pinar Coskun, Richard Jude Samulski
    Abstract:

    Mitochondrial myopathy, associated with muscle weakness and progressive external ophthalmoplegia, is caused by mutations in mitochondria oxidative phosphorylation genes including the heart–muscle isoform of the mitochondrial Adenine Nucleotide Translocator (ANT1). To develop therapies for mitochondrial disease, we have prepared a recombinant adeno-associated viral vector (rAAV) carrying the mouse Ant1 cDNA. This vector has been used to transduce muscle cells and muscle from Ant1 mutant mice, which manifest mitochondrial myopathy. AAV-ANT1 transduction resulted in long-term, stable expression of the Ant1 transgene in muscle precursor cells as well as differentiated muscle fibers. The transgene ANT1 protein was targeted to the mitochondrion, was inserted into the mitochondrial inner membrane, formed a functional ADP/ATP carrier, increased the mitochondrial export of ATP and reversed the histopathological changes associated with the mitochondrial myopathy. Thus, AAV transduction has the potential of providing symptomatic relief for the ophthalmoplegia and ptosis resulting from paralysis of the extraocular eye muscles cause by mutations in the Ant1 gene.

  • tgf β1 induction of the Adenine Nucleotide Translocator 1 in astrocytes occurs through smads and sp1 transcription factors
    2004
    Co-Authors: Alick K T Law, Douglas C Wallace, Deepak K Gupta, Shawn Levy, Robert J Mckeon, Charles Buck
    Abstract:

    The Adenine Nucleotide Translocator 1 (Ant1) is an inner mitochondrial membrane protein involved with energy mobilization during oxidative phosphorylation. We recently showed that rodent Ant1 is upregulated by transforming growth factor-beta (TGF-β) in reactive astrocytes following CNS injury. In the present study, we describe the molecular mechanisms by which TGF-β1 regulates Ant1 gene expression in cultured primary rodent astrocytes. Transcription reporter analysis verified that TGF-β1 regulates transcription of the mouse Ant1 gene, but not the gene encoding the closely related Ant2 isoform. A 69 basepair TGF-β1 responsive element of the Ant1 promoter was also identified. Electrophoretic mobility shift assays demonstrated that astrocyte nuclear proteins bind to this response element and TGF-β1 treatment recruits additional nuclear protein binding to this element. Antibody supershift and promoter deletion analyses demonstrated that Sp1 consensus binding sites in the RE are important for TGF-β1 regulation of Ant1 in astrocytes. Additionally, we demonstrate that Smad 2, 3 and 4 transcription factors are expressed in injured cerebral cortex and in primary astrocyte cultures. TGF-β1 activated Smad transcription factors also contribute to Ant1 regulation since transcription reporter assays in the presence of dominant negative (DN)-Smads 3 and 4 significantly reduced induction of Ant1 by TGF-β1. The specific regulation of Ant1 by TGF-β1 in astrocytes involves a cooperative interaction of both Smad and Sp1 binding elements located immediately upstream of the transcriptional start site. The first report of expression of Smads 2, 3 and 4 in astrocytes provided here is consistent with a regulation of Ant1 gene expression by these transcription factors in reactive astrocytes. Given the similarity in TGF-β1 regulation of Ant1 with other genes that are thought to promote neuronal survival, this interaction may represent a general mechanism that underlies the neuroprotective effects of TGF-β1.

  • up regulation of nuclear and mitochondrial genes in the skeletal muscle of mice lacking the heart muscle isoform of the Adenine Nucleotide Translocator
    1999
    Co-Authors: Deborah G Murdock, Braden E Boone, Luke A Esposito, Douglas C Wallace
    Abstract:

    Mice deficient in the heart/muscle specific isoform of the Adenine Nucleotide Translocator (ANT1) exhibit many of the hallmarks of human oxidative phosphorylation (OXPHOS) disease, including a dramatic proliferation of skeletal muscle mitochondria. Because many of the genes necessary for mitochondrial biosynthesis, OXPHOS function, and response to OXPHOS disease might be expected to be up-regulated in the Ant1(-/-) mouse, we used differential display reverse transcription-polymerase chain reaction techniques in an effort to identify these genes. 17 genes were identified as up-regulated in Ant1-deficient mice, and they fall into four categories: 1) nuclear and mitochondrial genes encoding OXPHOS components, 2) mitochondrial tRNA and rRNA genes, 3) genes involved in intermediary metabolism, and 4) an eclectic group of other genes. Among the latter genes, we identified the gene encoding anti-apoptotic Mcl-1, the Skd3 gene, and the WS-3 gene, which were previously unknown to be related to mitochondrial function. These results indicate that identification of genes up-regulated in the skeletal muscle of the Ant1-deficient mouse provides a novel method for identifying mammalian genes required for mitochondrial biogenesis.

  • a mouse model for mitochondrial myopathy and cardiomyopathy resulting from a deficiency in the heart muscle isoform of the Adenine Nucleotide Translocator
    1997
    Co-Authors: Brett H Graham, Katrina G Waymire, Barbara A Cottrell, Ian A Trounce, Grant R Macgregor, Douglas C Wallace
    Abstract:

    In an attempt to create an animal model of tissue-specif ic mitochondrial disease, we generated ‘knockout’ mice deficient in the heart/muscle isoform of the Adenine Nucleotide Translocator (Ant1). Histological and ultrastructural examination of skeletal muscle from Ant1 null mutants revealed ragged-red muscle fibers and a dramatic proliferation of mitochondria, while examination of the heart revealed cardiac hypertrophy with mitochondrial proliferation. Mitochondria isolated from mutant skeletal muscle exhibited a severe defect in coupled respiration. Ant1 mutant adults also had a resting serum lactate level fourfold higher than that of controls, indicative of metabolic acidosis. Significantly, mutant adults manifested severe exercise intolerance. Therefore, Ant1 mutant mice have the biochemical, histological, metabolic and physiological characteristics of mitochondrial myopathy and cardiomyopathy.

  • differential expression of Adenine Nucleotide Translocator isoforms in mammalian tissues and during muscle cell differentiation
    1992
    Co-Authors: G Stepien, Antonio Torroni, A B Chung, J A Hodge, Douglas C Wallace
    Abstract:

    The Adenine Nucleotide Translocator (ANT) catalyzes the exchange of ADP and ATP across the mitochondrial internal membrane. Its three isoforms, ANT1, ANT2, and ANT3 are coded by differentially regulated nuclear genes. The patterns of expression of these genes in human, bovine, and mouse tissue are similar. ANT1 is highly expressed in heart and skeletal muscle and is induced during myoblast differentiation. It is coordinately regulated with the nuclear gene for the mitochondrial ATP synthase beta subunit, with which it shares the positive muscle cis element, the OXBOX. ANT2 is either absent or weakly expressed in all tissues. ANT3 is ubiquitously expressed in all tissues, and its transcript level is proportional to the level of oxidative metabolism. The tissue-specific expression of the ANT gene family thus provides insight into the molecular basis of the differential reliance of mammalian tissues on oxidative phosphorylation.