Mitochondrial permeability transition in neuronal damage promoted by Ca2+ and respiratory chain complex II inhibition

Abstract Background Macrophages, besides resting latently infected CD4+ T cells, constitute the predominant stable, major non-T cell HIV reservoirs. Therefore, it is essential to eliminate both latently infected CD4+ T cells and tissue macrophages to completely eradicate HIV in patients. Until now, most of the research focus is directed towards eliminating latently infected CD4+ T cells. However, few approaches have been directed at killing of HIV-infected macrophages either in vitro or in vivo. HIV infection dysregulates the expression of many host genes essential for the survival of infected cells. We postulated that exploiting this alteration may yield novel targets for the selective killing of infected macrophages. Methods We applied a pooled shRNA-based genome-wide approach by employing a lentivirus-based library of shRNAs to screen novel gene targets whose inhibition should selectively induce apoptosis in HIV-infected macrophages. Primary human MDMs were infected with HIV-eGFP and HIV-HSA viruses. Infected MDMs were transfected with siRNAs specific for the promising genes followed by analysis of apoptosis by flow cytometry using labelled Annexin-V in HIV-infected, HIV-exposed but uninfected bystander MDMs and uninfected MDMs. The results were analyzed using student’s t-test from at least four independent experiments. Results We validated 28 top hits in two independent HIV infection models. This culminated in the identification of four target genes, Cox7a2, Znf484, Cstf2t, and Cdk2, whose loss-of-function induced apoptosis preferentially in HIV-infected macrophages. Silencing these single genes killed significantly higher number of HIV-HSA-infected MDMs compared to the HIV-HSA-exposed, uninfected bystander macrophages, indicating the specificity in the killing of HIV-infected macrophages. The mechanism governing Cox7a2-mediated apoptosis of HIV-infected macrophages revealed that targeting respiratory chain complex II and IV genes also selectively induced apoptosis of HIV-infected macrophages possibly through enhanced ROS production. Conclusions We have identified above-mentioned novel genes and specifically the respiratory chain complex II and IV genes whose silencing may cause selective elimination of HIV-infected macrophages and eventually the HIV-macrophage reservoirs. The results highlight the potential of the identified genes as targets for eliminating HIV-infected macrophages in physiological environment as part of an HIV cure strategy.

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Cocaine- and amphetamine-regulated transcript peptide increases mitochondrial respiratory chain complex II activity and protects against oxygen–glucose deprivation in neurons

Brain Research ◽

10.1016/j.brainres.2014.07.043 ◽

2014 ◽

Vol 1582 ◽

pp. 107-113 ◽

Cited By ~ 9

Author(s):

Dujuan Sha ◽

Luna Wang ◽

Jun Zhang ◽

Lai Qian ◽

Qiming Li ◽

...

Keyword(s):

Respiratory Chain ◽

Chain Complex ◽

Glucose Deprivation ◽

Mitochondrial Respiratory Chain ◽

Oxygen Glucose Deprivation ◽

Respiratory Chain Complex ◽

Complex Ii ◽

Mitochondrial Respiratory Chain Complex ◽

Mitochondrial Respiratory

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The P66Shc/Mitochondrial Permeability Transition Pore Pathway Determines Neurodegeneration

Oxidative Medicine and Cellular Longevity ◽

10.1155/2013/719407 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 28

Author(s):

Costanza Savino ◽

PierGiuseppe Pelicci ◽

Marco Giorgio

Keyword(s):

Oxidative Stress ◽

Knockout Mice ◽

Mitochondrial Permeability Transition ◽

Neuronal Damage ◽

Permeability Transition Pore ◽

Permeability Transition ◽

Mitochondrial Swelling ◽

Cyclophilin D ◽

Knock Out ◽

Mitochondrial Permeability

Mitochondrial-mediated oxidative stress and apoptosis play a crucial role in neurodegenerative disease and aging. Both mitochondrial permeability transition (PT) and swelling of mitochondria have been involved in neurodegeneration. Indeed, knockout mice for cyclophilin-D (Cyc-D), a key regulatory component of the PT pore (PTP) that triggers mitochondrial swelling, resulted to be protected in preclinical models of multiple sclerosis (MS), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS). However, how neuronal stress is transduced into mitochondrial oxidative stress and swelling is unclear. Recently, the aging determinant p66Shc that generates H2O2reacting with cytochrome c and induces oxidation of PTP and mitochondrial swelling was found to be involved in MS and ALS. To investigate the role of p66Shc/PTP pathway in neurodegeneration, we performed experimental autoimmune encephalomyelitis (EAE) experiments in p66Shc knockout mice (p66Shc−/−), knock out mice for cyclophilin-D (Cyc-D−/−), and p66Shc Cyc-D double knock out (p66Shc/Cyc-D−/−) mice. Results confirm that deletion of p66Shc protects from EAE without affecting immune response, whereas it is not epistatic to the Cyc-D mutation. These findings demonstrate that p66Shc contributes to EAE induced neuronal damage most likely through the opening of PTP suggesting that p66Shc/PTP pathway transduces neurodegenerative stresses.

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