scholarly journals Inhibition of mitochondrial permeability transition by deletion of the ANT family and CypD

2019 ◽  
Vol 5 (8) ◽  
pp. eaaw4597 ◽  
Author(s):  
Jason Karch ◽  
Michael J. Bround ◽  
Hadi Khalil ◽  
Michelle A. Sargent ◽  
Nadina Latchman ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Adenine Nucleotide ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Null Mouse ◽  
Cyclophilin D ◽  
Inner Membrane ◽  
Membrane Pore ◽  
Mitochondrial Permeability

The mitochondrial permeability transition pore (MPTP) has resisted molecular identification. The original model of the MPTP that proposed the adenine nucleotide translocator (ANT) as the inner membrane pore-forming component was challenged when mitochondria from Ant1/2 double null mouse liver still had MPTP activity. Because mice express three Ant genes, we reinvestigated whether the ANTs comprise the MPTP. Liver mitochondria from Ant1, Ant2, and Ant4 deficient mice were highly refractory to Ca2+-induced MPTP formation, and when also given cyclosporine A (CsA), the MPTP was completely inhibited. Moreover, liver mitochondria from mice with quadruple deletion of Ant1, Ant2, Ant4, and Ppif (cyclophilin D, target of CsA) lacked Ca2+-induced MPTP formation. Inner-membrane patch clamping in mitochondria from Ant1, Ant2, and Ant4 triple null mouse embryonic fibroblasts showed a loss of MPTP activity. Our findings suggest a model for the MPTP consisting of two distinct molecular components: The ANTs and an unknown species requiring CypD.

scholarly journals Inhibition of mitochondrial permeability transition by deletion of the ANT family and CypD

2018 ◽  
Author(s):  
Jason Karch ◽  
Michael J. Bround ◽  
Hadi Khalil ◽  
Michelle A. Sargent ◽  
Nadina Latchman ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Adenine Nucleotide ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Null Mouse ◽  
Inner Membrane ◽  
Membrane Pore ◽  
Mitochondrial Permeability

AbstractThe mitochondrial permeability transition pore (MPTP) has resisted molecular identification for decades. The original model of the MPTP had the adenine nucleotide translocator (ANT) as the inner membrane pore-forming component. Indeed, reconstitution experiments showed that recombinant or purified ANT generates MPTP-like pores in lipid bilayers. This model was challenged when mitochondria from Ant1/2 double null mouse liver still showed MPTP activity. Because mice contain and express 3 Ant genes, here we reinvestigated the genetic basis for the ANTs as comprising the MPTP. Liver mitochondria from Ant1, Ant2, and Ant4 deficient mice were highly refractory to Ca2+-induced MPT, and when also given cyclosporine A, MPT was completely inhibited. Moreover, liver mitochondria from mice with quadruple deletion of Ant1, Ant2, Ant4 and Ppif (cyclophilin D, target of CsA) lacked Ca2+-induced MPT. Finally, inner membrane patch clamping in mitochondria from Ant1, Ant2 and Ant4 triple null mouse embryonic fibroblasts (MEFs) showed a loss of MPT-like pores. Our findings suggest a new model of MPT consisting of two distinct molecular components, one of which is the ANTs and the other of which is unknown but requires CypD.One Sentence SummaryGenetic deletion of Ant1/2/4 and Ppif in mice fully inhibits the mitochondrial permeability transition pore

scholarly journals Cyclophilin-D promotes the mitochondrial permeability transition but has opposite effects on apoptosis and necrosis

2004 ◽  
Vol 383 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Yanmin LI ◽  
Nicholas JOHNSON ◽  
Michela CAPANO ◽  
Mina EDWARDS ◽  
Martin CROMPTON
Keyword(s):  
Oxidative Stress ◽  
Cell Injury ◽  
Mitochondrial Permeability Transition ◽  
Adenine Nucleotide ◽  
Permeability Transition ◽  
Cyclophilin D ◽  
Intact Cells ◽  
Inner Membrane ◽  
Mitochondrial Permeability ◽  
Apoptosis And Necrosis

Cyclophilin-D is a peptidylprolyl cis–trans isomerase of the mitochondrial matrix. It is involved in mitochondrial permeability transition, in which the adenine nucleotide translocase of the inner membrane is transformed from an antiporter to a non-selective pore. The permeability transition has been widely considered as a mechanism in both apoptosis and necrosis. The present study examines the effects of cyclophilin-D on the permeability transition and lethal cell injury, using a neuronal (B50) cell line stably overexpressing cyclophilin-D in mitochondria. Cyclophilin-D overexpression rendered isolated mitochondria far more susceptible to the permeability transition induced by Ca2+ and oxidative stress. Similarly, cyclophilin-D overexpression brought forward the onset of the permeability transition in intact cells subjected to oxidative stress. In addition, in the absence of stress, the mitochondria of cells overexpressing cyclophilin-D maintained a lower inner-membrane potential than those of normal cells. All these effects of cyclophilin-D overexpression were abolished by cyclosporin A. It is concluded that cyclophilin-D promotes the permeability transition in B50 cells. However, cyclophilin-D overexpression had opposite effects on apoptosis and necrosis; whereas NO-induced necrosis was promoted, NO- and staurosporine-induced apoptosis were inhibited. These findings indicate that the permeability transition leads to cell necrosis, but argue against its involvement in apoptosis.

The mitochondrial permeability transition pore

1999 ◽  
Vol 66 ◽  
pp. 167-179 ◽  
Author(s):  
Martin Crompton ◽  
Sukaina Virji ◽  
Veronica Doyle ◽  
Nicholas Johnson ◽  
John M. Ward
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Adenine Nucleotide ◽  
Permeability Transition Pore ◽  
Anion Channel ◽  
Permeability Transition ◽  
Adenine Nucleotide Translocase ◽  
Voltage Dependent Anion Channel ◽  
Inner Membrane ◽  
Membrane Pore ◽  
Voltage Dependent

This chapter reviews recent advances in the identification of the structural elements of the permeability transition pore. The discovery that cyclosporin A (CsA) inhibits the pore proved instrumental. Various approaches indicate that CsA blocks the pore by binding to cyclophilin (CyP)-D. In particular, covalent labelling of CyP-D in situ by a photoactive CsA derivative has shown that pore ligands have the same effects on the degree to which CsA both blocks the pore and binds to CyP-D. The recognition that CyP-D is a key component has enabled the other constituents to be resolved. Use of a CyP-D fusion protein as affinity matrix has revealed that CyP-D binds very strongly to 1:1 complexes of the voltage-dependent anion channel (from the outer membrane) and adenine nucleotide translocase (inner membrane). Our current model envisages that the pore arises as a complex between these three components at contact sites between the mitochondrial inner and outer membranes. This is in line with recent reconstitutions of pore activity from protein fractions containing these proteins. The strength of interaction between these proteins suggests that it may be a permanent feature rather than assembled only under pathological conditions. Calcium, the key activator of the pore, does not appear to affect pore assembly; rather, an allosteric action allowing pore flicker into an open state is indicated. CsA inhibits pore flicker and lowers the binding affinity for calcium. Whether adenine nucleotide translocase or the voltage-dependent anion channel (via inner membrane insertion) provides the inner membrane pore has not been settled, and data relevant to this issue are also documented.

scholarly journals Phosphate is not an absolute requirement for the inhibitory effects of cyclosporin A or cyclophilin D deletion on mitochondrial permeability transition

2012 ◽  
Vol 443 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Allison M. McGee ◽  
Christopher P. Baines
Keyword(s):  
Cyclosporin A ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Cyclophilin D ◽  
Wild Type ◽  
Inhibitory Effects ◽  
Mitochondrial Permeability ◽  
Pre Treatment

CypD (cyclophilin D) has been established as a critical regulator of the MPT (mitochondrial permeability transition) pore, and pharmacological or genetic inhibition of CypD attenuates MPT in numerous systems. However, it has recently been suggested that the inhibitory effects of CypD inhibition only manifest when Pi (inorganic phosphate) is present, and that inhibition is lost when Pi is replaced by Asi (inorganic arsenate) or Vi (inorganic vanadate). To test this, liver mitochondria were isolated from wild-type and CypD-deficient (Ppif−/−) mice and then incubated in buffer containing Pi, Asi or Vi. MPT was induced under both energized and de-energized conditions by the addition of Ca2+, and the resultant mitochondrial swelling was measured spectrophotometrically. For pharmacological inhibition of CypD, wild-type mitochondria were pre-incubated with CsA (cyclosporin A) before the addition of Ca2+. In energized and de-energized mitochondria, Ca2+ induced MPT regardless of the anion present, although the magnitude differed between Pi, Asi and Vi. However, in all cases, pre-treatment with CsA significantly inhibited MPT. Moreover, these effects were independent of mouse strain, organ type and rodent species. Similarly, attenuation of Ca2+-induced MPT in the Ppif−/− mitochondria was still observed irrespective of whether Pi, Asi or Vi was present. We conclude that the pharmacological and genetic inhibition of CypD is still able to attenuate MPT even in the absence of Pi.

scholarly journals Chronic ethanol consumption enhances sensitivity to Ca2+-mediated opening of the mitochondrial permeability transition pore and increases cyclophilin D in liver

2010 ◽  
Vol 299 (4) ◽  
pp. G954-G966 ◽  
Author(s):  
Adrienne L. King ◽  
Telisha M. Swain ◽  
Dale A. Dickinson ◽  
Mathieu J. Lesort ◽  
Shannon M. Bailey
Keyword(s):  
Gene Expression ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Cyclophilin D ◽  
Retention Capacity ◽  
Mitochondrial Permeability ◽  
Chronic Ethanol Consumption

Chronic ethanol consumption increases mitochondrial oxidative stress and sensitivity to form the mitochondrial permeability transition pore (MPTP). The mechanism responsible for increased MPTP sensitivity in ethanol-exposed mitochondria and its relation to mitochondrial Ca2+ handling is unknown. Herein, we investigated whether increased sensitivity to MPTP induction in liver mitochondria from ethanol-fed rats compared with controls is related to an ethanol-dependent change in mitochondrial Ca2+ accumulation. Liver mitochondria were isolated from control and ethanol-fed rats, and Ca2+-mediated induction of the MPTP and mitochondrial Ca2+ retention capacity were measured. Levels of proposed MPTP proteins as well as select pro- and antiapoptotic proteins were measured along with gene expression. We observed increased steatosis and TUNEL-stained nuclei in liver of ethanol-fed rats compared with controls. Liver mitochondria from ethanol-fed rats had increased levels of proapoptotic Bax protein and reduced Ca2+ retention capacity compared with control mitochondria. We observed increased cyclophilin D (Cyp D) gene expression in liver and protein in mitochondria from ethanol-fed animals compared with controls, whereas there was no change in the adenine nucleotide translocase and voltage-dependent anion channel. Together, these results suggest that enhanced sensitivity to Ca2+-mediated MPTP induction may be due, in part, to higher Cyp D levels in liver mitochondria from ethanol-fed rats. Therefore, therapeutic strategies aimed at normalizing Cyp D levels may be beneficial in preventing ethanol-dependent mitochondrial dysfunction and liver injury.

scholarly journals Time Dependent Ca2+ Induction Led to the Formation of Mitochondrial Permeability Transition Pore as a Function of Age

2020 ◽  
Vol 5 (6) ◽  
pp. 572-581
Author(s):  
Mohan Kumar BS ◽  
Mahaboob Basha P
Keyword(s):  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Adenine Nucleotide ◽  
Age Groups ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Time Dependent ◽  
Cyclophilin D ◽  
Mitochondrial Permeability ◽  
Age Related

Ca2+ sequestration and its homeostasis is disrupted when mitochondrial membrane permeabilises to form a large opening - the mitochondrial permeability transition pore (MPTP). The MPTP formation is common during aging and age related pathologies, activating cell death pathways to avoid unhealthy consequences and malignancies in the brain tissue. Several studies have identified the participation of Cyclophilin-D (Cyp-D) and adenine nucleotide translocase(ANT) in forming MPTP. However, Ca2+ is known to participate significantly in MPTP induction, although its concentration and time dependent permeabilization mechanisms are still elusive. In this work, we have focused on the contribution of Ca2+ participation, its concentration and time taken to permeabilze the mitochondrial inner membrane as a measure of light scattering at 540 ηM. We have observed that MPTP formation is increased in mitochondria isolated from aged rats in comparison to young adult and neonatal rats. The cyclosporin A application blocks the cyclophilin interaction thus avoiding MPTP formation confirming the crucial role of Ca2+ inducted MPTP opening. A 100 µM Ca2+ incubation for 15 minutes allowed the 50% probability of formation of MPTP in mitochondria isolated from all age groups. Thus, alleviating its role in aging and neurodegeneration.

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