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Mitochondria-associated membranes (MAMs) and inflammation. Cell Death Dis 2018; 9:329. [PMID: 29491386 PMCID: PMC5832426 DOI: 10.1038/s41419-017-0027-2] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/26/2017] [Accepted: 09/27/2017] [Indexed: 12/18/2022]
Abstract
The endoplasmic reticulum (ER) and mitochondria are tightly associated with very dynamic platforms termed mitochondria-associated membranes (MAMs). MAMs provide an excellent scaffold for crosstalk between the ER and mitochondria and play a pivotal role in different signaling pathways that allow rapid exchange of biological molecules to maintain cellular health. However, dysfunctions in the ER–mitochondria architecture are associated with pathological conditions and human diseases. Inflammation has emerged as one of the various pathways that MAMs control. Inflammasome components and other inflammatory factors promote the release of pro-inflammatory cytokines that sustain pathological conditions. In this review, we summarize the critical role of MAMs in initiating inflammation in the cellular defense against pathogenic infections and the association of MAMs with inflammation-mediated diseases.
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Sieprath T, Corne T, Robijns J, Koopman WJH, De Vos WH. Cellular Redox Profiling Using High-content Microscopy. J Vis Exp 2017. [PMID: 28570523 DOI: 10.3791/55449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Reactive oxygen species (ROS) regulate essential cellular processes including gene expression, migration, differentiation and proliferation. However, excessive ROS levels induce a state of oxidative stress, which is accompanied by irreversible oxidative damage to DNA, lipids and proteins. Thus, quantification of ROS provides a direct proxy for cellular health condition. Since mitochondria are among the major cellular sources and targets of ROS, joint analysis of mitochondrial function and ROS production in the same cells is crucial for better understanding the interconnection in pathophysiological conditions. Therefore, a high-content microscopy-based strategy was developed for simultaneous quantification of intracellular ROS levels, mitochondrial membrane potential (ΔΨm) and mitochondrial morphology. It is based on automated widefield fluorescence microscopy and image analysis of living adherent cells, grown in multi-well plates, and stained with the cell-permeable fluorescent reporter molecules CM-H2DCFDA (ROS) and TMRM (ΔΨm and mitochondrial morphology). In contrast with fluorimetry or flow-cytometry, this strategy allows quantification of subcellular parameters at the level of the individual cell with high spatiotemporal resolution, both before and after experimental stimulation. Importantly, the image-based nature of the method allows extracting morphological parameters in addition to signal intensities. The combined feature set is used for explorative and statistical multivariate data analysis to detect differences between subpopulations, cell types and/or treatments. Here, a detailed description of the assay is provided, along with an example experiment that proves its potential for unambiguous discrimination between cellular states after chemical perturbation.
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Affiliation(s)
- Tom Sieprath
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp; Cell Systems and Imaging Research Group (CSI), Department of Molecular Biotechnology, Ghent University
| | - Tobias Corne
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp; Cell Systems and Imaging Research Group (CSI), Department of Molecular Biotechnology, Ghent University
| | - Joke Robijns
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp
| | - Werner J H Koopman
- Department of Biochemistry , Radboud Institute for Molecular Life Sciences, Radboud University Medical Center
| | - Winnok H De Vos
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp; Cell Systems and Imaging Research Group (CSI), Department of Molecular Biotechnology, Ghent University;
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Sieprath T, Corne TDJ, Willems PHGM, Koopman WJH, De Vos WH. Integrated High-Content Quantification of Intracellular ROS Levels and Mitochondrial Morphofunction. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2016; 219:149-77. [PMID: 27207366 DOI: 10.1007/978-3-319-28549-8_6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oxidative stress arises from an imbalance between the production of reactive oxygen species (ROS) and their removal by cellular antioxidant systems. Especially under pathological conditions, mitochondria constitute a relevant source of cellular ROS. These organelles harbor the electron transport chain, bringing electrons in close vicinity to molecular oxygen. Although a full understanding is still lacking, intracellular ROS generation and mitochondrial function are also linked to changes in mitochondrial morphology. To study the intricate relationships between the different factors that govern cellular redox balance in living cells, we have developed a high-content microscopy-based strategy for simultaneous quantification of intracellular ROS levels and mitochondrial morphofunction. Here, we summarize the principles of intracellular ROS generation and removal, and we explain the major considerations for performing quantitative microscopy analyses of ROS and mitochondrial morphofunction in living cells. Next, we describe our workflow, and finally, we illustrate that a multiparametric readout enables the unambiguous classification of chemically perturbed cells as well as laminopathy patient cells.
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Affiliation(s)
- Tom Sieprath
- Cell Systems and Imaging Research Group (CSI), Department of Molecular Biotechnology, Ghent University, Ghent, Belgium.,Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Tobias D J Corne
- Cell Systems and Imaging Research Group (CSI), Department of Molecular Biotechnology, Ghent University, Ghent, Belgium.,Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Peter H G M Willems
- Department of Biochemistry (286), Radboud University Medical Centre (RUMC), Radboud Institute for Molecular Life Sciences (RIMLS), Nijmegen, The Netherlands
| | - Werner J H Koopman
- Department of Biochemistry (286), Radboud University Medical Centre (RUMC), Radboud Institute for Molecular Life Sciences (RIMLS), Nijmegen, The Netherlands
| | - Winnok H De Vos
- Cell Systems and Imaging Research Group (CSI), Department of Molecular Biotechnology, Ghent University, Ghent, Belgium. .,Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium.
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4
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Morris G, Berk M, Walder K, Maes M. The Putative Role of Viruses, Bacteria, and Chronic Fungal Biotoxin Exposure in the Genesis of Intractable Fatigue Accompanied by Cognitive and Physical Disability. Mol Neurobiol 2015; 53:2550-71. [PMID: 26081141 DOI: 10.1007/s12035-015-9262-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 05/28/2015] [Indexed: 01/08/2023]
Abstract
Patients who present with severe intractable apparently idiopathic fatigue accompanied by profound physical and or cognitive disability present a significant therapeutic challenge. The effect of psychological counseling is limited, with significant but very slight improvements in psychometric measures of fatigue and disability but no improvement on scientific measures of physical impairment compared to controls. Similarly, exercise regimes either produce significant, but practically unimportant, benefit or provoke symptom exacerbation. Many such patients are afforded the exclusionary, non-specific diagnosis of chronic fatigue syndrome if rudimentary testing fails to discover the cause of their symptoms. More sophisticated investigations often reveal the presence of a range of pathogens capable of establishing life-long infections with sophisticated immune evasion strategies, including Parvoviruses, HHV6, variants of Epstein-Barr, Cytomegalovirus, Mycoplasma, and Borrelia burgdorferi. Other patients have a history of chronic fungal or other biotoxin exposure. Herein, we explain the epigenetic factors that may render such individuals susceptible to the chronic pathology induced by such agents, how such agents induce pathology, and, indeed, how such pathology can persist and even amplify even when infections have cleared or when biotoxin exposure has ceased. The presence of active, reactivated, or even latent Herpes virus could be a potential source of intractable fatigue accompanied by profound physical and or cognitive disability in some patients, and the same may be true of persistent Parvovirus B12 and mycoplasma infection. A history of chronic mold exposure is a feasible explanation for such symptoms, as is the presence of B. burgdorferi. The complex tropism, life cycles, genetic variability, and low titer of many of these pathogens makes their detection in blood a challenge. Examination of lymphoid tissue or CSF in such circumstances may be warranted.
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Affiliation(s)
- Gerwyn Morris
- Tir Na Nog, Bryn Road seaside 87, Llanelli, SA15 2LW, Wales, UK
| | - Michael Berk
- IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia.,Orygen, The National Centre of Excellence in Youth Mental Health, Department of Psychiatry and The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Ken Walder
- Centre for Molecular and Medical Research, School of Medicine, Deakin University, Geelong, Australia
| | - Michael Maes
- IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia. .,Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
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5
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Lopimune-induced mitochondrial toxicity is attenuated by increased uncoupling protein-2 level in treated mouse hepatocytes. Biochem J 2015; 468:401-7. [PMID: 26173235 DOI: 10.1042/bj20150195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/13/2015] [Indexed: 02/01/2023]
Abstract
Although the protease inhibitor (PI) Lopimune has proven to be effective, no studies have examined the side effects of Lopimune on mitochondrial bioenergetics in hepatocytes. The objective of the present study is to evaluate mitochondrial respiration, production of reactive oxygen species (ROS) and expression of uncoupling protein-2 (UCP2) in mouse hepatocytes following Lopimune administration. Mitochondria were extracted from mouse liver using differential centrifugation and hepatocytes were isolated by the collagenase perfusion procedure. Mitochondrial respiration was measured using a Rank Brothers oxygen electrode. ROS production in hepatocytes was monitored by flow cytometry using a 2',7'-dichlorofluorescin diacetate probe and UCP2 protein expression was detected by Western blotting. We found that Lopimune induced a significant decrease of approximately 30% in the respiratory control ratio (RCR) starting from day 4 until day 9 of treatment. This decrease was due to an increase in state 4 respiration, reflecting an increase in mitochondrial proton leak. State 2 and state 3 respirations were not affected. Moreover, ROS production significantly increased by about 2-fold after day 1 of treatment and decreased after day 3, returning to the resting level on day 5. Interestingly, UCP2 which is absent from control hepatocytes, was expressed starting from day 4 of treatment. Our findings indicate that Lopimune-induced proton leak, mediated by UCP2, may represent a response to inhibit the production of ROS as a negative feedback regulatory mechanism. These results imply a potential involvement of UCP2 in the regulation of oxidative stress and add new insights into the understanding of mitochondrial toxicity induced by PIs.
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6
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Superresolution imaging of viral protein trafficking. Med Microbiol Immunol 2015; 204:449-60. [PMID: 25724304 DOI: 10.1007/s00430-015-0395-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 02/13/2015] [Indexed: 12/25/2022]
Abstract
The endoplasmic reticulum (ER) membrane is closely apposed to the outer mitochondrial membrane (OMM), which facilitates communication between these organelles. These contacts, known as mitochondria-associated membranes (MAM), facilitate calcium signaling, lipid transfer, as well as antiviral and stress responses. How cellular proteins traffic to the MAM, are distributed therein, and interact with ER and mitochondrial proteins are subject of great interest. The human cytomegalovirus UL37 exon 1 protein or viral mitochondria-localized inhibitor of apoptosis (vMIA) is crucial for viral growth. Upon synthesis at the ER, vMIA traffics to the MAM and OMM, where it reprograms the organization and function of these compartments. vMIA significantly changes the abundance of cellular proteins at the MAM and OMM, including proteins that regulate calcium homeostasis and cell death. Through the use of superresolution imaging, we have shown that vMIA is distributed at the OMM in nanometer scale clusters. This is similar to the clusters reported for the mitochondrial calcium channel, VDAC, as well as electron transport chain, translocase of the OMM complex, and mitochondrial inner membrane organizing system components. Thus, aside from addressing how vMIA targets the MAM and regulates survival of infected cells, biochemical studies and superresolution imaging of vMIA offer insights into the formation, organization, and functioning of MAM. Here, we discuss these insights into trafficking, function, and organization of vMIA at the MAM and OMM and discuss how the use of superresolution imaging is contributing to the study of the formation and trafficking of viruses.
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Bociąga-Jasik M, Polus A, Góralska J, Czech U, Gruca A, Śliwa A, Garlicki A, Mach T, Dembińska-Kieć A. Metabolic effects of the HIV protease inhibitor--saquinavir in differentiating human preadipocytes. Pharmacol Rep 2014; 65:937-50. [PMID: 24145088 DOI: 10.1016/s1734-1140(13)71075-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 03/12/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND The iatrogenic, HIV-related lipodystrophy is associated with development of the significant metabolic and cardiovascular complications. The underlying mechanisms of antiretroviral (ARV) drugs are not completely explored. METHODS The aim of the study was to characterize effects of the protease inhibitor (PI)--saquinavir (SQV) on metabolic functions, and gene expression during differentiation in cells (Chub-S7) culture. RESULTS SQV in concentrations observed during antiretroviral therapy (ART) significantly decreased mitochondrial membrane potential (MMP), oxygen consumption and ATP generation. The effects were greater in already differentiated cells. This was accompanied by characteristic changes in the expression of the genes involved in endoplasmic reticulum (ER) stress, and differentiation (lipid droplet formation) process such as: WNT10a, C/EBPa, AFT4, CIDEC, ADIPOQ, LPIN1. CONCLUSIONS The results indicate that SQV affects not only metabolic (mitochondrial) activity of adipocytes, but affects the expression of genes related to differentiation and to a lesser extent to cell apoptosis.
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Affiliation(s)
- Monika Bociąga-Jasik
- Chair of Gastroenterology, Hepatology and Infectious Diseases, Department of Infectious Diseases, Jagiellonian University, Collegium Medicum, Sniadeckich 5, PL 31-501 Kraków, Poland.
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8
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Bhuvanendran S, Salka K, Rainey K, Sreetama SC, Williams E, Leeker M, Prasad V, Boyd J, Patterson GH, Jaiswal JK, Colberg-Poley AM. Superresolution imaging of human cytomegalovirus vMIA localization in sub-mitochondrial compartments. Viruses 2014; 6:1612-36. [PMID: 24721787 PMCID: PMC4014713 DOI: 10.3390/v6041612] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/16/2014] [Accepted: 03/27/2014] [Indexed: 01/04/2023] Open
Abstract
The human cytomegalovirus (HCMV) viral mitochondria-localized inhibitor of apoptosis (vMIA) protein, traffics to mitochondria-associated membranes (MAM), where the endoplasmic reticulum (ER) contacts the outer mitochondrial membrane (OMM). vMIA association with the MAM has not been visualized by imaging. Here, we have visualized this by using a combination of confocal and superresolution imaging. Deconvolution of confocal microscopy images shows vMIA localizes away from mitochondrial matrix at the Mitochondria-ER interface. By gated stimulated emission depletion (GSTED) imaging, we show that along this interface vMIA is distributed in clusters. Through multicolor, multifocal structured illumination microscopy (MSIM), we find vMIA clusters localize away from MitoTracker Red, indicating its OMM localization. GSTED and MSIM imaging show vMIA exists in clusters of ~100–150 nm, which is consistent with the cluster size determined by Photoactivated Localization Microscopy (PALM). With these diverse superresolution approaches, we have imaged the clustered distribution of vMIA at the OMM adjacent to the ER. Our findings directly compare the relative advantages of each of these superresolution imaging modalities for imaging components of the MAM and sub-mitochondrial compartments. These studies establish the ability of superresolution imaging to provide valuable insight into viral protein location, particularly in the sub-mitochondrial compartments, and into their clustered organization.
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Affiliation(s)
- Shivaprasad Bhuvanendran
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
| | - Kyle Salka
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
| | - Kristin Rainey
- Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Sen Chandra Sreetama
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
| | - Elizabeth Williams
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
| | - Margretha Leeker
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
| | - Vidhya Prasad
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
| | - Jonathan Boyd
- Life Science Division, Leica Microsystems, Inc., 1700 Leider Lane, Buffalo Grove, IL 60089, USA.
| | - George H Patterson
- Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jyoti K Jaiswal
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
| | - Anamaris M Colberg-Poley
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Health System, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
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Reyskens KMSE, Essop MF. HIV protease inhibitors and onset of cardiovascular diseases: a central role for oxidative stress and dysregulation of the ubiquitin-proteasome system. Biochim Biophys Acta Mol Basis Dis 2013; 1842:256-68. [PMID: 24275553 DOI: 10.1016/j.bbadis.2013.11.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/09/2013] [Accepted: 11/18/2013] [Indexed: 12/18/2022]
Abstract
The successful roll-out of highly active antiretroviral therapy (HAART) has extended life expectancy and enhanced the overall well-being of HIV-positive individuals. There are, however, increased concerns regarding HAART-mediated metabolic derangements and its potential risk for cardiovascular diseases (CVD) in the long-term. Here certain classes of antiretroviral drugs such as the HIV protease inhibitors (PIs) are strongly implicated in this process. This article largely focuses on the direct PI-linked development of cardio-metabolic complications, and reviews the inter-linked roles of oxidative stress and the ubiquitin-proteasome system (UPS) as key mediators driving this process. It is proposed that PIs trigger reactive oxygen species (ROS) production that leads to serious downstream consequences such as cell death, impaired mitochondrial function, and UPS dysregulation. Moreover, we advocate that HIV PIs may also directly lower myocardial UPS function. The attenuation of cardiac UPS can initiate transcriptional changes that contribute to perturbed lipid metabolism, thereby fueling a pro-atherogenic milieu. It may also directly alter ionic channels and interfere with electrical signaling in the myocardium. Therefore HIV PI-induced ROS together with a dysfunctional UPS elicit detrimental effects on the cardiovascular system that will eventually result in the onset of heart diseases. Thus while HIV PIs substantially improve life expectancy and quality of life in HIV-positive patients, its longer-term side-effects on the cardiovascular system should lead to a) greater clinical awareness regarding its benefit-harm paradigm, and b) the development and evaluation of novel co-treatment strategies.
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Affiliation(s)
- Kathleen M S E Reyskens
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7600, South Africa
| | - M Faadiel Essop
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7600, South Africa.
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10
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Smith RL, de Boer R, Brul S, Budovskaya Y, van Spek H. Premature and accelerated aging: HIV or HAART? Front Genet 2013; 3:328. [PMID: 23372574 PMCID: PMC3556597 DOI: 10.3389/fgene.2012.00328] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/29/2012] [Indexed: 01/09/2023] Open
Abstract
Highly active antiretroviral therapy (HAART) has significantly increased life expectancy of the human immunodeficiency virus (HIV)-positive population. Nevertheless, the average lifespan of HIV-patients remains shorter compared to uninfected individuals. Immunosenescence, a current explanation for this difference invokes heavily on viral stimulus despite HAART efficiency in viral suppression. We propose here that the premature and accelerated aging of HIV-patients can also be caused by adverse effects of antiretroviral drugs, specifically those that affect the mitochondria. The nucleoside reverse transcriptase inhibitor (NRTI) antiretroviral drug class for instance, is known to cause depletion of mitochondrial DNA via inhibition of the mitochondrial specific DNA polymerase-γ. Besides NRTIs, other antiretroviral drug classes such as protease inhibitors also cause severe mitochondrial damage by increasing oxidative stress and diminishing mitochondrial function. We also discuss important areas for future research and argue in favor of the use of Caenorhabditis elegans as a novel model system for studying these effects.
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Affiliation(s)
- Reuben L Smith
- Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands
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11
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Apostolova N, Blas-García A, Esplugues JV. Mitochondrial interference by anti-HIV drugs: mechanisms beyond Pol-γ inhibition. Trends Pharmacol Sci 2011; 32:715-25. [PMID: 21899897 DOI: 10.1016/j.tips.2011.07.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/27/2011] [Accepted: 07/29/2011] [Indexed: 02/06/2023]
Abstract
The combined pharmacological approach to the treatment of HIV infection, known as highly active antiretroviral therapy (HAART), has dramatically reduced AIDS-related morbidity and mortality. However, its use has been associated with serious adverse reactions, of which those resulting from mitochondrial dysfunction are particularly widespread. Nucleos(t)ide-reverse transcriptase inhibitors (NRTIs) have long been considered the main source of HAART-related mitochondrial toxicity due to their ability to inhibit Pol-γ, the DNA polymerase responsible for the synthesis of mitochondrial DNA. Nevertheless, accumulating evidence points to a more complex relationship between these organelles and NRTIs. Also, alternative pathways by which other groups of anti-HIV drugs (non-nucleoside reverse transcriptase inhibitors and protease inhibitors) interfere with mitochondria have been suggested, although their implications, both pharmacological and clinical, are open to debate. This review aims to provide a comprehensive overview of the mechanisms and factors which influence the mitochondrial involvement in the toxicity of all three major classes of anti-HIV drugs.
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Affiliation(s)
- Nadezda Apostolova
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Avda Blasco Ibáñez n.15-17, 46010 Valencia, Spain
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12
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Emerging Role for Members of the Bcl-2 Family in Mitochondrial Morphogenesis. Mol Cell 2009; 36:355-63. [DOI: 10.1016/j.molcel.2009.10.011] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 10/19/2009] [Indexed: 12/23/2022]
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13
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Williamson CD, Colberg-Poley AM. Access of viral proteins to mitochondria via mitochondria-associated membranes. Rev Med Virol 2009; 19:147-64. [PMID: 19367604 DOI: 10.1002/rmv.611] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
By exploiting host cell machineries, viruses provide powerful tools for gaining insight into cellular pathways. Proteins from two unrelated viruses, human CMV (HCMV) and HCV, are documented to traffic sequentially from the ER into mitochondria, probably through the mitochondria-associated membrane (MAM) compartment. The MAM are sites of ER-mitochondrial contact enabling the direct transfer of membrane bound lipids and the generation of high calcium (Ca2+) microdomains for mitochondria signalling and responses to cellular stress. Both HCV core protein and HCMV UL37 proteins are associated with Ca2+ regulation and apoptotic signals. Trafficking of viral proteins to the MAM may allow viruses to manipulate a variety of fundamental cellular processes, which converge at the MAM, including Ca2+ signalling, lipid synthesis and transfer, bioenergetics, metabolic flow, and apoptosis. Because of their distinct topologies and targeted MAM sub-domains, mitochondrial trafficking (albeit it through the MAM) of the HCMV and HCV proteins predictably involves alternative pathways and, hence, distinct targeting signals. Indeed, we found that multiple cellular and viral proteins, which target the MAM, showed no apparent consensus primary targeting sequences. Nonetheless, these viral proteins provide us with valuable tools to access the poorly characterised MAM compartment, to define its cellular constituents and describe how virus infection alters these to its own end. Furthermore, because proper trafficking of viral proteins is necessary for their function, discovering the requirements for MAM to mitochondrial trafficking of essential viral proteins may provide novel targets for the rational design of anti-viral drugs.
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Affiliation(s)
- Chad D Williamson
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Medical Center, 111 Michigan Ave, NW, Washington, DC 20010, USA.
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14
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Zhang S, Carper MJ, Lei X, Cade WT, Yarasheski KE, Ramanadham S. Protease inhibitors used in the treatment of HIV+ induce beta-cell apoptosis via the mitochondrial pathway and compromise insulin secretion. Am J Physiol Endocrinol Metab 2009; 296:E925-35. [PMID: 19208856 PMCID: PMC2670620 DOI: 10.1152/ajpendo.90445.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inclusion of HIV protease inhibitors (PIs) in the treatment of people living with HIV+ has markedly decreased mortality but also increased the incidence of metabolic abnormalities, causes of which are not well understood. Here, we report that insulinopenia is exacerbated when Zucker fa/fa rats are exposed to a PI for 7 wk, suggesting that chronic PI exposure adversely affects pancreatic islet beta-cell function. In support of this possibility, we find increased apoptosis, as reflected by TUNEL fluorescence analyses, and reduced insulin-secretory capacity in insulinoma cells and human pancreatic islet cells after in vitro exposures (48-96 h) to clinically relevant PIs (ritonavir, lopinavir, atazanavir, or tipranavir). Furthermore, pancreatic islets isolated from rats administered an HIV-PI for 3 wk exhibit greater cell death than islets isolated from vehicle-administered rats. The higher incidence of HIV-PI-induced cell death was associated with cleavage and, hence, activation of caspase-3 and poly(ADP)-ribose polymerase but not with activation of phospho-pancreatic endoplasmic reticulum (ER) kinase or induction of ER stress apoptotic factor C/EBP homologous protein. Exposure to the HIV-PIs, however, led to activation of mitochondria-associated caspase-9, caused a loss in mitochondrial membrane potential, and promoted the release of cytochrome c, suggesting that HIV-PIs currently in clinically use can induce beta-cell apoptosis by activating the mitochondrial apoptotic pathway. These findings therefore highlight the importance of considering beta-cell viability and function when assessing loss of glycemic control and the course of development of diabetes in HIV+ subjects receiving a protease inhibitor.
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Affiliation(s)
- Sheng Zhang
- Washington University School of Medicine, Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, 660 S. Euclid Ave., Box 8127, St. Louis, MO 63110, USA
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15
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Unexpected role of the phosphate carrier in mitochondrial fragmentation. Cell Death Differ 2008; 15:616-8. [PMID: 18174900 DOI: 10.1038/sj.cdd.4402295] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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16
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Sharon-Friling R, Goodhouse J, Colberg-Poley AM, Shenk T. Human cytomegalovirus pUL37x1 induces the release of endoplasmic reticulum calcium stores. Proc Natl Acad Sci U S A 2006; 103:19117-22. [PMID: 17135350 PMCID: PMC1748185 DOI: 10.1073/pnas.0609353103] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The human CMV UL37x1-encoded protein, also known as the viral mitochondria-localized inhibitor of apoptosis, traffics to the endoplasmic reticulum and mitochondria of infected cells. It induces the fragmentation of mitochondria and blocks apoptosis. We demonstrate that UL37x1 protein mobilizes Ca(2+) from the endoplasmic reticulum into the cytosol. This release is accompanied by cell rounding, cell swelling, and reorganization of the actin cytoskeleton, and these morphological changes can be substantially blocked by a Ca(2+) chelating agent. The UL37x1-mediated release of Ca(2+) from the endoplasmic reticulum likely has multiple consequences, including induction of the unfolded protein response, modulation of mitochondrial function, induction of mitochondrial fission, and protection against apoptotic stimuli.
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Affiliation(s)
- Ronit Sharon-Friling
- *Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014; and
| | - Joseph Goodhouse
- *Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014; and
| | - Anamaris M. Colberg-Poley
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010
| | - Thomas Shenk
- *Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014; and
- To whom correspondence should be addressed. E-mail:
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17
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Poncet D, Pauleau AL, Szabadkai G, Vozza A, Scholz SR, Le Bras M, Brière JJ, Jalil A, Le Moigne R, Brenner C, Hahn G, Wittig I, Schägger H, Lemaire C, Bianchi K, Souquère S, Pierron G, Rustin P, Goldmacher VS, Rizzuto R, Palmieri F, Kroemer G. Cytopathic effects of the cytomegalovirus-encoded apoptosis inhibitory protein vMIA. ACTA ACUST UNITED AC 2006; 174:985-96. [PMID: 16982800 PMCID: PMC2064390 DOI: 10.1083/jcb.200604069] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Replication of human cytomegalovirus (CMV) requires the expression of the viral mitochondria–localized inhibitor of apoptosis (vMIA). vMIA inhibits apoptosis by recruiting Bax to mitochondria, resulting in its neutralization. We show that vMIA decreases cell size, reduces actin polymerization, and induces cell rounding. As compared with vMIA-expressing CMV, vMIA-deficient CMV, which replicates in fibroblasts expressing the adenoviral apoptosis suppressor E1B19K, induces less cytopathic effects. These vMIA effects can be separated from its cell death–inhibitory function because vMIA modulates cellular morphology in Bax-deficient cells. Expression of vMIA coincided with a reduction in the cellular adenosine triphosphate (ATP) level. vMIA selectively inhibited one component of the ATP synthasome, namely, the mitochondrial phosphate carrier. Exposure of cells to inhibitors of oxidative phosphorylation produced similar effects, such as an ATP level reduced by 30%, smaller cell size, and deficient actin polymerization. Similarly, knockdown of the phosphate carrier reduced cell size. Our data suggest that the cytopathic effect of CMV can be explained by vMIA effects on mitochondrial bioenergetics.
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Affiliation(s)
- Delphine Poncet
- Centre National de la Recherche Scientifique, FRE2939, Institut Gustave Roussy, F-94805 Villejuif, France
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18
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Szabadkai G, Simoni AM, Bianchi K, De Stefani D, Leo S, Wieckowski MR, Rizzuto R. Mitochondrial dynamics and Ca2+ signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:442-9. [PMID: 16750865 DOI: 10.1016/j.bbamcr.2006.04.002] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 03/28/2006] [Accepted: 04/04/2006] [Indexed: 11/18/2022]
Abstract
Recent data shed light on two novel aspects of the mitochondria-Ca2+ liaison. First, it was extensively investigated how Ca2+ handling is controlled by mitochondrial shape, and positioning; a playground also of cell death and survival regulation. On the other hand, significant progress has been made to explore how intra- and near-mitochondrial Ca2+ signals modify mitochondrial morphology and cellular distribution. Here, we shortly summarize these advances and provide a model of Ca2+-mitochondria interactions.
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Affiliation(s)
- G Szabadkai
- Department of Experimental and Diagnostic Medicine and Interdisciplinary Center for the Study of Inflammation and ER-GenTech, University of Ferrara, Italy
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