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Kim T, Morshed MN, Londhe AM, Lim JW, Lee HE, Cho S, Cho SJ, Hwang H, Lim SM, Lee JY, Lee J, Pae AN. The translocator protein ligands as mitochondrial functional modulators for the potential anti-Alzheimer agents. J Enzyme Inhib Med Chem 2021; 36:831-846. [PMID: 33752569 PMCID: PMC7996082 DOI: 10.1080/14756366.2021.1900158] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 11/06/2022] Open
Abstract
Small molecule modulators of mitochondrial function have been attracted much attention in recent years due to their potential therapeutic applications for neurodegenerative diseases. The mitochondrial translocator protein (TSPO) is a promising target for such compounds, given its involvement in the formation of the mitochondrial permeability transition pore in response to mitochondrial stress. In this study, we performed a ligand-based pharmacophore design and virtual screening, and identified a potent hit compound, 7 (VH34) as a TSPO ligand. After validating its biological activity against amyloid-β (Aβ) induced mitochondrial dysfunction and in acute and transgenic Alzheimer's disease (AD) model mice, we developed a library of analogs, and we found two most active compounds, 31 and 44, which restored the mitochondrial membrane potential, ATP production, and cell viability under Aβ-induced mitochondrial toxicity. These compounds recovered learning and memory function in acute AD model mice with improved pharmacokinetic properties.
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Affiliation(s)
- TaeHun Kim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
| | - Mohammad N. Morshed
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
- Center for Advanced Research in Sciences (CARS), University of Dhaka, Dhaka, Bangladesh
| | - Ashwini M. Londhe
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
| | - Ji W. Lim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, Republic of Korea
| | - Ha E. Lee
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
| | - Suengmok Cho
- Department of Food Science and Technology, Pukyong National University, Pusan, Republic of Korea
| | - Sung J. Cho
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu, Republic of Korea
| | - Hayoung Hwang
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu, Republic of Korea
| | - Sang M. Lim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
| | - Jae Y. Lee
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, Republic of Korea
| | - Jiyoun Lee
- Department of Global Medical Science, Sungshin University, Seoul, Republic of Korea
| | - Ae N. Pae
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, Republic of Korea
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Blevins LK, Crawford RB, Azzam DJ, Guilarte TR, Kaminski NE. Surface translocator protein 18 kDa (TSPO) localization on immune cells upon stimulation with LPS and in ART-treated HIV + subjects. J Leukoc Biol 2020; 110:123-140. [PMID: 33205494 DOI: 10.1002/jlb.3a1219-729rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 10/23/2020] [Accepted: 10/26/2020] [Indexed: 11/09/2022] Open
Abstract
Translocator protein 18 kDa (TSPO) is a well-known outer mitochondrial membrane protein and it is widely used as a biomarker of neuroinflammation and brain injury. Although it is thought that TSPO plays key roles in a multitude of host cell functions, including steroid biosynthesis, apoptosis, generation of reactive oxygen species, and proliferation, some of these functions have recently been questioned. Here, we report the unexpected finding that circulating immune cells differentially express basal levels of TSPO on their cell surface, with a high percentage of monocytes and neutrophils expressing cell surface TSPO. In vitro stimulation of monocytes with LPS significantly increases the frequency of cells with surface TSPO expression in the absence of altered gene expression. Importantly, the LPS increase in TSPO cell surface expression in monocytes appears to be selective for LPS because two other distinct monocyte activators failed to increase the frequency of cells with surface TSPO. Finally, when we quantified immune cell TSPO surface expression in antiretroviral therapy-treated HIV+ donors, a chronic inflammatory disease, we found significant increases in the frequency of TSPO surface localization, which could be pharmacologically suppressed with ∆9 -tetrahydrocannabinol. These findings suggest that cell surface TSPO in circulating leukocytes could serve as a peripheral blood-based biomarker of inflammation.
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Affiliation(s)
- Lance K Blevins
- Department of Pharmacology and Toxicology, Center for Research on Ingredient Safety, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Robert B Crawford
- Department of Pharmacology and Toxicology, Center for Research on Ingredient Safety, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Diana J Azzam
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, Florida, USA
| | - Tomás R Guilarte
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, Florida, USA
| | - Norbert E Kaminski
- Department of Pharmacology and Toxicology, Center for Research on Ingredient Safety, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
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Ammer LM, Vollmann-Zwerenz A, Ruf V, Wetzel CH, Riemenschneider MJ, Albert NL, Beckhove P, Hau P. The Role of Translocator Protein TSPO in Hallmarks of Glioblastoma. Cancers (Basel) 2020; 12:cancers12102973. [PMID: 33066460 PMCID: PMC7602186 DOI: 10.3390/cancers12102973] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 12/18/2022] Open
Abstract
Simple Summary The translocator protein (TSPO) has been under extensive investigation as a specific marker in positron emission tomography (PET) to visualize brain lesions following injury or disease. In recent years, TSPO is increasingly appreciated as a potential novel therapeutic target in cancer. In Glioblastoma (GBM), the most malignant primary brain tumor, TSPO expression levels are strongly elevated and scientific evidence accumulates, hinting at a pivotal role of TSPO in tumorigenesis and glioma progression. The aim of this review is to summarize the current literature on TSPO with respect to its role both in diagnostics and especially with regard to the critical hallmarks of cancer postulated by Hanahan and Weinberg. Overall, our review contributes to a better understanding of the functional significance of TSPO in Glioblastoma and draws attention to TSPO as a potential modulator of treatment response and thus an important factor that may influence the clinical outcome of GBM. Abstract Glioblastoma (GBM) is the most fatal primary brain cancer in adults. Despite extensive treatment, tumors inevitably recur, leading to an average survival time shorter than 1.5 years. The 18 kDa translocator protein (TSPO) is abundantly expressed throughout the body including the central nervous system. The expression of TSPO increases in states of inflammation and brain injury due to microglia activation. Not least due to its location in the outer mitochondrial membrane, TSPO has been implicated with a broad spectrum of functions. These include the regulation of proliferation, apoptosis, migration, as well as mitochondrial functions such as mitochondrial respiration and oxidative stress regulation. TSPO is frequently overexpressed in GBM. Its expression level has been positively correlated to WHO grade, glioma cell proliferation, and poor prognosis of patients. Several lines of evidence indicate that TSPO plays a functional part in glioma hallmark features such as resistance to apoptosis, invasiveness, and proliferation. This review provides a critical overview of how TSPO could regulate several aspects of tumorigenesis in GBM, particularly in the context of the hallmarks of cancer proposed by Hanahan and Weinberg in 2011.
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Affiliation(s)
- Laura-Marie Ammer
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
| | - Arabel Vollmann-Zwerenz
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
| | - Viktoria Ruf
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, 81377 Munich, Germany;
| | - Christian H. Wetzel
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany;
| | | | - Nathalie L. Albert
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, 81377 Munich, Germany;
| | - Philipp Beckhove
- Regensburg Center for Interventional Immunology (RCI) and Department Internal Medicine III, University Hospital Regensburg, 93053 Regensburg, Germany;
| | - Peter Hau
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
- Correspondence:
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Mnatsakanyan N, Jonas EA. The new role of F 1F o ATP synthase in mitochondria-mediated neurodegeneration and neuroprotection. Exp Neurol 2020; 332:113400. [PMID: 32653453 DOI: 10.1016/j.expneurol.2020.113400] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/23/2020] [Accepted: 07/07/2020] [Indexed: 02/08/2023]
Abstract
The mitochondrial F1Fo ATP synthase is one of the most abundant proteins of the mitochondrial inner membrane, which catalyzes the final step of oxidative phosphorylation to synthesize ATP from ADP and Pi. ATP synthase uses the electrochemical gradient of protons (ΔμH+) across the mitochondrial inner membrane to synthesize ATP. Under certain pathophysiological conditions, ATP synthase can run in reverse to hydrolyze ATP and build the necessary ΔμH+ across the mitochondrial inner membrane. Tight coupling between these two processes, proton translocation and ATP synthesis, is achieved by the unique rotational mechanism of ATP synthase and is necessary for efficient cellular metabolism and cell survival. The uncoupling of these processes, dissipation of mitochondrial inner membrane potential, elevated levels of ROS, low matrix content of ATP in combination with other cellular malfunction trigger the opening of the mitochondrial permeability transition pore in the mitochondrial inner membrane. In this review we will discuss the new role of ATP synthase beyond oxidative phosphorylation. We will highlight its function as a unique regulator of cell life and death and as a key target in mitochondria-mediated neurodegeneration and neuroprotection.
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Affiliation(s)
- Nelli Mnatsakanyan
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT, USA.
| | - Elizabeth Ann Jonas
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT, USA
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Mnatsakanyan N, Jonas EA. ATP synthase c-subunit ring as the channel of mitochondrial permeability transition: Regulator of metabolism in development and degeneration. J Mol Cell Cardiol 2020; 144:109-118. [PMID: 32461058 PMCID: PMC7877492 DOI: 10.1016/j.yjmcc.2020.05.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/07/2020] [Accepted: 05/20/2020] [Indexed: 12/29/2022]
Abstract
The mitochondrial permeability transition pore (mPTP) or mitochondrial megachannel is arguably one of the most mysterious phenomena in biology today. mPTP has been at the center of ongoing extensive scientific research for the last several decades. In this review we will discuss recent advances in the field that enhance our understanding of the molecular composition of mPTP, its regulatory mechanisms and its pathophysiological role. We will describe our recent findings on the role of ATP synthase c-subunit ring as a central player in mitochondrial permeability transition and as an important metabolic regulator during development and in degenerative diseases.
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Affiliation(s)
- Nelli Mnatsakanyan
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT, USA.
| | - Elizabeth Ann Jonas
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT, USA.
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Qiu ZK, Liu X, Chen Y, Wu RJ, Guan SF, Pan YY, Wang QB, Tang D, Zhu T, Chen JS. Translocator protein 18 kDa: a potential therapeutic biomarker for post traumatic stress disorder. Metab Brain Dis 2020; 35:695-707. [PMID: 32172519 DOI: 10.1007/s11011-020-00548-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 02/10/2020] [Indexed: 11/11/2022]
Abstract
Post traumatic stress disorder (PTSD) is widely regarded as a stress-related and trauma disorder. The symptoms of PTSD are characterized as a spectrum of vulnerabilities after the exposure to an extremely traumatic stressor. Considering as one of complex mental disorders, little progress has been made toward its diagnostic biomarkers, despite the involvement of PTSD has been studied. Many studies into the underlying neurobiology of PTSD implicated the dysfunction of neurosteroids biosynthesis and neuorinflammatory processes. Translocator protein 18 kDa (TSPO) has been considered as one of the promising therapeutic biomarkers for neurological stress disorders (like PTSD, depression, anxiety, et al) without the benzodiazepine-like side effects. This protein participates in the formation of neurosteroids and modulation of neuroinflammation. The review outlines current knowledge involving the role of TSPO in the neuropathology of PTSD and the anti-PTSD-like effects of TSPO ligands.
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Affiliation(s)
- Zhi-Kun Qiu
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Xu Liu
- Pharmacy Department of Medical Supplies Center of General Hospital of Chinese People's Armed Police Forces, Beijing, 100039, People's Republic of China
| | - Yong Chen
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Rong-Jia Wu
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Shi-Feng Guan
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Yun-Yun Pan
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Qian-Bo Wang
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Dan Tang
- Guangdong Provincial Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Tao Zhu
- Guangdong Provincial Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Ji-Sheng Chen
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China.
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Ovariectomy and obesity have equal impact in causing mitochondrial dysfunction and impaired skeletal muscle contraction in rats. Menopause 2019; 25:1448-1458. [PMID: 29994976 DOI: 10.1097/gme.0000000000001149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Previous studies have demonstrated that either an obese-insulin resistance condition or a condition involving loss of estrogen impaired skeletal muscle function as indicated by a decrease in muscle contraction. The differing effects of combined estrogen deficiency over obese-insulin resistance on skeletal muscle function have, however, not yet been determined. Our hypothesis was that estrogen deficiency aggravates skeletal muscle dysfunction in obese-insulin resistant rats, via increased muscle oxidative stress and mitochondrial dysfunction. METHODS Twenty-four female Wistar rats were divided into 2 groups and animals in each group were fed either a normal diet (ND) or a high-fat diet (HFD) for 24 weeks. At week 13, rats in each group were subdivided into 2 subgroups: sham-operated or ovariectomized (n = 6/subgroup). At the end of the experimental period the contraction of the gastrocnemius muscles was tested before the rats were sacrificed. Skeletal muscle was removed to assess oxidative stress and mitochondrial function. RESULTS We found that an obese-insulin resistant condition was observed in sham-operated HFD-fed rats, ovariectomized ND-fed rats, and ovariectomized HFD-fed rats. Skeletal muscle contractile function (peak-force ratio [g/g]; 25.40 ± 2.03 [ovariectomized ND-fed rats], 22.44 ± 0.85 [sham-operated HFD-fed rats] and 25.06 ± 0.61 [ovariectomized HFD-fed rats]), skeletal muscle mitochondrial function, and oxidative stress were equally significantly impaired in all 3 groups, when compared with those of sham-operated ND-fed rats (31.12 ± 1.88 g/g [NDS]; P < 0.05). Surprisingly, loss of estrogen did not aggravate these dysfunctions of skeletal muscles in HFD-fed rats. CONCLUSIONS These findings suggest that skeletal muscle dysfunction may occur due to increased muscle oxidative stress and mitochondrial dysfunction as a result of ovariectomy and obese-insulin resistance. Loss of estrogen, however, did not aggravate these impairments in the muscle of rats with obese-insulin resistant condition.
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Klee K, Storti F, Barben M, Samardzija M, Langmann T, Dunaief J, Grimm C. Systemic knockout of Tspo in mice does not affect retinal morphology, function and susceptibility to degeneration. Exp Eye Res 2019; 188:107816. [PMID: 31562844 DOI: 10.1016/j.exer.2019.107816] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 12/11/2022]
Abstract
Translocator protein (18 kDa) (TSPO) is a mitochondrial protein expressed by reactive microglia and astrocytes at the site of neuronal injury. Although TSPO function has not been fully determined, synthetic TSPO ligands have beneficial effects on different pathologies of the central nervous system, including the retina. Here, we studied the pattern of Tspo expression in the aging human retina and in two mouse models of retinal degeneration. Using a newly generated Tspo-KO mouse, we investigated the impact of the lack of TSPO on retinal morphology, function and susceptibility to degeneration. We show that TSPO was expressed in both human and mouse retina and retinal pigment epithelium (RPE). Tspo was induced in the mouse retina upon degeneration, but constitutively expressed in the RPE. Similarly, TSPO expression levels in healthy human retina and RPE were not differentially regulated during aging. Tspo-KO mice had normal retinal morphology and function up to 48 weeks of age. Photoreceptor loss caused either by exposure to excessive light levels or by a mutation in the phosphodiesterase 6b gene was not affected by the absence of Tspo. The reactivity states of retinal mononuclear phagocytes following light-damage were comparable in Tspo-KO and control mice. Our data suggest that lack of endogenous TSPO does not directly influence the magnitude of photoreceptor degeneration or microglia activation in these two models of retinal degeneration. We therefore hypothesize that the interaction of TSPO with its ligands may be required to modulate disease progression.
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Affiliation(s)
- Katrin Klee
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Federica Storti
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Maya Barben
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Marijana Samardzija
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Cologne, Germany
| | - Joshua Dunaief
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Christian Grimm
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Schlieren, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland; Neuroscience Center, University of Zurich, Zurich, Switzerland.
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Gong Z, Han Y, Wu L, Xia T, Ren H, Yang D, Gu D, Wang H, Hu C, He D, Zhou L, Zeng C. Translocator protein 18 kDa ligand alleviates neointimal hyperplasia in the diabetic rat artery injury model via activating PKG. Life Sci 2019; 221:72-82. [PMID: 30738868 DOI: 10.1016/j.lfs.2019.02.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 02/03/2019] [Accepted: 02/06/2019] [Indexed: 01/01/2023]
Abstract
AIMS The proliferation of VSMCs is the pathologic basis for intimal hyperplasia after angioplasty in diabetic patients. Translocator protein (TSPO), located in the outer mitochondrial membrane, has been found to regulate redox intermediate components in cell dysfunction. We hypothesized that TSPO may regulate VSMC proliferation and migration, and be involved in the intimal hyperplasia after angioplasty in diabetes. MATERIALS AND METHODS Cell proliferation was measured by cell counting and MTT assays. Cell migration was measured by Transwell® and scratch-wound assays. TSPO expression in arteries of rats and high glucose-treated A10 cells were detected by immunoblotting and immunofluorescence staining. Neointimal formation of carotid artery was induced by balloon injury in type 2 diabetic rat. KEY FINDINGS TSPO expression was increased in the arterial samples from diabetic rats and A10 cells treated with high glucose. Down-regulation of TSPO expression by siRNA decreased the high-glucose-induced VSMC proliferation and migration in A10 cells. This phenomenon could be simulated by using TSPO ligands, PK 11195 and Ro5-4864. cGMP/PKG signals were involved in the TSPO ligand action, since in the presence of cGMP or PKG inhibitor ODQ or KT5823 respectively, the effect of PK 11195 on VSMC proliferation was blocked. Furthermore, PK 11195 significantly inhibited neointimal formation by the inhibition of VSMC proliferation. SIGNIFICANCE This study suggests that TSPO inhibition suppresses the proliferation and migration of VSMCs induced by hyperglycemia, consequently, preventing atherosclerosis and restenosis after angioplasty in diabetic conditions. TSPO may be a potential therapeutic target to reduce arterial remodeling induced by angioplasty in diabetes.
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Affiliation(s)
- Zhengfan Gong
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Yu Han
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Lianpan Wu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Tianyang Xia
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Hongmei Ren
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Donghai Yang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Daqian Gu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - He Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China; Department of Cardiology, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, PR China
| | - Cuimei Hu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Duofen He
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China
| | - Lin Zhou
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China.
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China; Chongqing Institute of Cardiology, Chongqing Key Laboratory of Hypertension Research, Chongqing, PR China.
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Transcriptional regulation of Translocator protein (18 kDa) (TSPO) in microglia requires Pu.1, Ap1 and Sp factors. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:1119-1133. [PMID: 30412797 DOI: 10.1016/j.bbagrm.2018.10.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/12/2018] [Accepted: 10/31/2018] [Indexed: 11/21/2022]
Abstract
Mitochondrial Translocator protein (18 kDa) (TSPO) is strongly expressed in reactive microglia and serves as a therapeutic target for alleviation of neuronal degeneration. However, little is known about TSPO's transcriptional regulation in microglia. The aim of this study was to identify genetic elements and transcription factors required for basal and inducible TSPO expression in microglia. Murine Tspo promoter was cloned into the pGL4.10 luciferase vector and functionally characterized in BV-2 cells. Deletion mutagenesis indicated that -845 bases upstream were sufficient to reconstitute near maximal promoter activity in BV-2. Deletion of -593 to -520 sequences, which harbour an Ap1, Ets.2 and Nkx3.1 site which also serves as a non-canonical binding site for Sp1-family transcription factors, led to a dramatic decrease in both basal and LPS induced promoter activity. Further deletion of -168 to -39 sequences, which contains four GC boxes, also led to a significant decrease in promoter activity. Targeted mutations of Ap1, Ets.2, Nkx3.1/Sp1/3/4 and the GC boxes led to significant decreases in promoter activity. ChIP-qPCR revealed that Pu.1, Ap1, Stat3, Sp1, Sp3 and Sp4 bind to the endogenous Tspo promoter. Notably, binding of these factors, with the exception of Stat3, was significantly enhanced upon LPS treatment. RNAi silencing of Pu.1, cJun, cFos, Sp1, Sp3, Sp4 and Stat3 strongly lowered Tspo promoter activity while Ap1 silencing inhibited LPS induced increase in Tspo protein levels. These findings demonstrate that consensus binding sequences for Ap1, Ets.2, distal as well as proximal Sp1/3/4 sites regulate basal and LPS induced Tspo promoter activity in microglia.
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Görg B, Karababa A, Häussinger D. Hepatic Encephalopathy and Astrocyte Senescence. J Clin Exp Hepatol 2018; 8:294-300. [PMID: 30302047 PMCID: PMC6175776 DOI: 10.1016/j.jceh.2018.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/08/2018] [Indexed: 02/07/2023] Open
Abstract
Hepatic Encephalopathy (HE) is a severe complication of acute or chronic liver diseases with a broad spectrum of neurological symptoms including motor disturbances and cognitive impairment of different severity. Contrary to former beliefs, a growing number of studies suggest that cognitive impairment may not fully reverse after an acute episode of overt HE in patients with liver cirrhosis. The reasons for persistent cognitive impairment in HE are currently unknown but recent observations raise the possibility that astrocyte senescence may play a role here. Astrocyte senescence is closely related to oxidative stress and correlate with irreversible cognitive decline in aging and neurodegenerative diseases. In line with this, surrogate marker for oxidative stress and senescence were upregulated in ammonia-exposed cultured astrocytes and in post mortem brain tissue from patients with liver cirrhosis with but not without HE. Ammonia-induced senescence in astrocytes involves glutamine synthesis-dependent formation of reactive oxygen species (ROS), p53 activation and upregulation of cell cycle inhibitory factors p21 and GADD45α. More recent studies also suggest a role of ROS-induced downregulation of Heme Oxygenase (HO)1-targeting micro RNAs and upregulation of HO1 for ammonia-induced proliferation inhibition in cultured astrocytes. Further studies are required to identify the precise sequence of events that lead to astrocyte senescence and to elucidate functional implications of senescence for cognitive performance in patients with liver cirrhosis and HE.
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Key Words
- ARE, Antioxidant Response Elements
- BDNF, Brain-Derived Neurotrophic Factor
- Eph, Ephrine
- EphR, Ephrine Receptor
- GADD45α, Growth Arrest and DNA Damage Inducible 45α
- GS, Glutamine Synthetase
- HE, Hepatic Encephalopathy
- HO1, Heme Oxygenase 1
- LOLA, l-Ornithine-l-Aspartate
- MAP, Mitogen Activated Protein Kinases
- NAPDH, Reduced Form of Nicotinamide Adenine Dinucleotide Phosphate
- Nox, NADPH Oxidase
- Nrf2, Nuclear Factor-Like 2
- PBR, Peripheral-Type Benzodiazepine Receptor
- PTN, Protein Tyrosine Nitration
- RNOS, Reactive Nitrogen and Oxygen Species
- ROS, Reactive Oxygen Species
- SA-β-Gal, Senescence-Associated β-d-Galactosidase
- TSP, Trombospondin
- TrkBT, Truncated Tyrosine Receptor Kinase B
- ZnPP, Zinc Protoporphyrin
- ammonia
- astrocytes
- heme oxygenase 1
- hepatic encephalopathy
- mPT, Mitochondrial Permeability Transition
- miRNAs
- nNOS, Neuronal-Type Nitric-Oxide Synthase
- oxidative stress
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Affiliation(s)
| | | | - Dieter Häussinger
- Address for correspondence: Dieter Häussinger, Universitätsklinikum Düsseldorf, Klinik für Gastroenterologie, Hepatologie und Infektiologie, Moorenstrasse 5, 40225 Düsseldorf, Germany. Tel.: +49 211 811 7569; fax: +49 211 811 8838.
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12
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Bonsack F, Sukumari-Ramesh S. TSPO: An Evolutionarily Conserved Protein with Elusive Functions. Int J Mol Sci 2018; 19:ijms19061694. [PMID: 29875327 PMCID: PMC6032217 DOI: 10.3390/ijms19061694] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 12/22/2022] Open
Abstract
TSPO (18 kDa translocator protein) was identified decades ago in a search for peripheral tissue binding sites for benzodiazepines, and was formerly called the peripheral benzodiazepine receptor. TSPO is a conserved protein throughout evolution and it is implicated in the regulation of many cellular processes, including inflammatory responses, oxidative stress, and mitochondrial homeostasis. TSPO, apart from its broad expression in peripheral tissues, is highly expressed in neuroinflammatory cells, such as activated microglia. In addition, emerging studies employing the ligands of TSPO suggest that TSPO plays an important role in neuropathological settings as a biomarker and therapeutic target. However, the precise molecular function of this protein in normal physiology and neuropathology remains enigmatic. This review provides an overview of recent advances in our understanding of this multifaceted molecule and identifies the knowledge gap in the field for future functional studies.
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Affiliation(s)
- Frederick Bonsack
- Department of Neurosurgery, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA.
| | - Sangeetha Sukumari-Ramesh
- Department of Neurosurgery, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA.
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13
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Damaging Effects of Bisphenol A on the Kidney and the Protection by Melatonin: Emerging Evidences from In Vivo and In Vitro Studies. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:3082438. [PMID: 29670679 PMCID: PMC5835250 DOI: 10.1155/2018/3082438] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 12/11/2017] [Accepted: 12/31/2017] [Indexed: 12/12/2022]
Abstract
This study investigates the effects of bisphenol A (BPA) contamination on the kidney and the possible protection by melatonin in experimental rats and isolated mitochondrial models. Rats exposed to BPA (50, 100, and 150 mg/kg, i.p.) for 5 weeks demonstrated renal damages as evident by increased serum urea and creatinine and decreased creatinine clearance, together with the presence of proteinuria and glomerular injuries in a dose-dependent manner. These changes were associated with increased lipid peroxidation and decreased antioxidant glutathione and superoxide dismutase. Mitochondrial dysfunction was also evident as indicated by increased reactive oxygen species production, decreased membrane potential change, and mitochondrial swelling. Coadministration of melatonin resulted in the reversal of all the changes caused by BPA. Studies using isolated mitochondria showed that BPA incubation produced dose-dependent impairment in mitochondrial function. Preincubation with melatonin was able to sustain mitochondrial function and architecture and decreases oxidative stress upon exposure to BPA. The findings indicated that BPA is capable of acting directly on the kidney mitochondria, causing mitochondrial oxidative stress, dysfunction, and subsequently, leading to whole organ damage. Emerging evidence further suggests the protective benefits of melatonin against BPA nephrotoxicity, which may be mediated, in part, by its ability to diminish oxidative stress and maintain redox equilibrium within the mitochondria.
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14
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Notter T, Coughlin JM, Sawa A, Meyer U. Reconceptualization of translocator protein as a biomarker of neuroinflammation in psychiatry. Mol Psychiatry 2018; 23:36-47. [PMID: 29203847 DOI: 10.1038/mp.2017.232] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 09/05/2017] [Accepted: 10/02/2017] [Indexed: 02/06/2023]
Abstract
A great deal of interest in psychiatric research is currently centered upon the pathogenic role of inflammatory processes. Positron emission tomography (PET) using radiolabeled ligands selective for the 18 kDa translocator protein (TSPO) has become the most widely used technique to assess putative neuroimmune abnormalities in vivo. Originally used to detect discrete neurotoxic damages, TSPO has generally turned into a biomarker of 'neuroinflammation' or 'microglial activation'. Psychiatric research has mostly accepted these denotations of TSPO, even if they may be inadequate and misleading under many pathological conditions. A reliable and neurobiologically meaningful diagnosis of 'neuroinflammation' or 'microglial activation' is unlikely to be achieved by the sole use of TSPO PET imaging. It is also very likely that the pathological meanings of altered TSPO binding or expression are disease-specific, and therefore, not easily generalizable across different neuropathologies or inflammatory conditions. This difficulty is intricately linked to the varying (and still ill-defined) physiological functions and cellular expression patterns of TSPO in health and disease. While altered TSPO binding or expression may indeed mirror ongoing neuroinflammatory processes in some cases, it may reflect other pathophysiological processes such as abnormalities in cell metabolism, energy production and oxidative stress in others. Hence, the increasing popularity of TSPO PET imaging has paradoxically introduced substantial uncertainty regarding the nature and meaning of neuroinflammatory processes and microglial activation in psychiatry, and likely in other neuropathological conditions as well. The ambiguity of conceiving TSPO simply as a biomarker of 'neuroinflammation' or 'microglial activation' calls for alternative interpretations and complimentary approaches. Without the latter, the ongoing scientific efforts and excitement surrounding the role of the neuroimmune system in psychiatry may not turn into therapeutic hope for affected individuals.
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Affiliation(s)
- T Notter
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - J M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - A Sawa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - U Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
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15
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Thummasorn S, Shinlapawittayatorn K, Khamseekaew J, Jaiwongkam T, Chattipakorn SC, Chattipakorn N. Humanin directly protects cardiac mitochondria against dysfunction initiated by oxidative stress by decreasing complex I activity. Mitochondrion 2017; 38:31-40. [PMID: 28802666 DOI: 10.1016/j.mito.2017.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/12/2017] [Accepted: 08/07/2017] [Indexed: 10/19/2022]
Abstract
Humanin (HN) is an endogenous peptide that exerts cytoprotection against oxidative stress and apoptosis. We recently reported that Humanin analogue (HNG) pretreatment can reduce reactive oxygen species production in the heart subjected to ischemia/reperfusion (I/R) injury via attenuating mitochondrial dysfunction. However, it is unclear if HNG has direct effects on mitochondrial function against oxidative stress. Thus, we sought to determine the effects of HNG on mitochondrial function under hydrogen peroxide (H2O2) induced oxidative stress in isolated cardiac mitochondria. We found that HNG has direct protective effects on cardiac mitochondrial function against H2O2 induced oxidative stress through decreasing complex I activity.
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Affiliation(s)
- Savitree Thummasorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Krekwit Shinlapawittayatorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Juthamas Khamseekaew
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Thidarat Jaiwongkam
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand; Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai 50200, Thailand.
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16
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Mitochondria in Structural and Functional Cardiac Remodeling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:277-306. [PMID: 28551793 DOI: 10.1007/978-3-319-55330-6_15] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The heart must function continuously as it is responsible for both supplying oxygen and nutrients throughout the entire body, as well as for the transport of waste products to excretory organs. When facing either a physiological or pathological increase in cardiac demand, the heart undergoes structural and functional remodeling as a means of adapting to increased workload. These adaptive responses can include changes in gene expression, protein composition, and structure of sub-cellular organelles involved in energy production and metabolism. Mitochondria are essential for cardiac function, as they supply the ATP necessary to support continuous cycles of contraction and relaxation. In addition, mitochondria carry out other important processes, including synthesis of essential cellular components, calcium buffering, and initiation of cell death signals. Not surprisingly, mitochondrial dysfunction has been linked to several cardiovascular disorders, including hypertension, cardiac hypertrophy, ischemia/reperfusion and heart failure. The present chapter will discuss how changes in mitochondrial cristae structure, fusion/fission dynamics, fatty acid oxidation, ATP production, and the generation of reactive oxygen species might impact cardiac structure and function, particularly in the context of pathological hypertrophy and fibrotic response. In addition, the mechanistic role of mitochondria in autophagy and programmed cell death of cardiomyocytes will be addressed. Here we will also review strategies to improve mitochondrial function and discuss their cardioprotective potential.
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17
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Shackebaei D, Feizollahi F, Hesari M, Bahrami G. The Effect of Diazepam on the Function of Hypertrophied Rats’ Hearts in Ischemia-Reperfusion Conditions. Int Cardiovasc Res J 2016. [DOI: 10.17795/icrj-10(2)89] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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18
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Nanegrungsunk D, Apaijai N, Yarana C, Sripetchwandee J, Limpastan K, Watcharasaksilp W, Vaniyapong T, Chattipakorn N, Chattipakorn SC. Bevacizumab is superior to Temozolomide in causing mitochondrial dysfunction in human brain tumors. Neurol Res 2016; 38:285-93. [PMID: 27078710 DOI: 10.1080/01616412.2015.1114233] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Current chemotherapy treatments available for treating high-grade brain tumors, Temozolomide (TMZ) or Bevacizumab (BEV), not only have specific anti-tumor mechanisms, but also have an effect on mitochondria. However, effects of both drugs on mitochondria isolated from human brain tumors have not been thoroughly investigated. This study determined the direct effects of TMZ and BEV as well as the neurotoxic condition (calcium overload), on the function of mitochondria and compared these effects on mitochondria isolated from low- and high-grade human brain tumors. METHODS Mitochondria were isolated from either low- or high-grade human primary brain tumors. Calcium overload conditions (100 or 200 μM), TMZ (300 μM), and BEV (2 mg/mL) were applied to isolated mitochondria from low- and high-grade brain tumors. Following the treatment, mitochondrial function, including reactive oxygen species production, membrane potential changes, and swelling, were determined. The mitochondrial morphology was also examined. RESULTS In calcium overload conditions, mitochondrial dysfunction was only found to have occurred in low-grade tumors. In TMZ and BEV treatment, BEV, rather than TMZ, caused greater membrane depolarization and mitochondrial swelling in both grades of brain tumors. CONCLUSIONS TMZ and BEV can directly cause the dysfunction of mitochondria isolated from human brain tumors. However, BEV has a greater ability to disturb mitochondrial function in mitochondria isolated from human brain tumors than either TMZ or calcium overload conditions.
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Affiliation(s)
- Danop Nanegrungsunk
- a Department of Anesthesiology, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand.,b Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Nattayaporn Apaijai
- b Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Chontida Yarana
- b Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Jirapas Sripetchwandee
- b Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Kriengsak Limpastan
- c Neurosurgery Division, Department of Surgery, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Wanarak Watcharasaksilp
- c Neurosurgery Division, Department of Surgery, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Tanat Vaniyapong
- c Neurosurgery Division, Department of Surgery, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Nipon Chattipakorn
- b Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand
| | - Siriporn C Chattipakorn
- b Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine , Chiang Mai University , Chiang Mai , Thailand.,d Department of Oral Biology and Diagnostic Science, Faculty of Dentistry , Chiang Mai University , Chiang Mai , Thailand
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19
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Kumfu S, Chattipakorn SC, Fucharoen S, Chattipakorn N. Dual T-type and L-type calcium channel blocker exerts beneficial effects in attenuating cardiovascular dysfunction in iron-overloaded thalassaemic mice. Exp Physiol 2016; 101:521-39. [DOI: 10.1113/ep085517] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/27/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Sirinart Kumfu
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine; Chiang Mai University; Chiang Mai Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine; Chiang Mai University; Chiang Mai Thailand
- Center of Excellence in Cardiac Electrophysiology Research; Chiang Mai University; Chiang Mai Thailand
| | - Siriporn C. Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine; Chiang Mai University; Chiang Mai Thailand
- Center of Excellence in Cardiac Electrophysiology Research; Chiang Mai University; Chiang Mai Thailand
- Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry; Chiang Mai University; Chiang Mai Thailand
| | - Suthat Fucharoen
- Thalassemia Research Center, Institute of Molecular Biosciences; Mahidol University; Nakhon Pathom Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine; Chiang Mai University; Chiang Mai Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine; Chiang Mai University; Chiang Mai Thailand
- Center of Excellence in Cardiac Electrophysiology Research; Chiang Mai University; Chiang Mai Thailand
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20
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Morin D, Musman J, Pons S, Berdeaux A, Ghaleh B. Mitochondrial translocator protein (TSPO): From physiology to cardioprotection. Biochem Pharmacol 2015; 105:1-13. [PMID: 26688086 DOI: 10.1016/j.bcp.2015.12.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/04/2015] [Indexed: 01/08/2023]
Abstract
The mitochondrial translocator protein (TSPO) is a high affinity cholesterol binding protein which is primarily located in the outer mitochondrial membrane where it has been shown to interact with proteins implicated in mitochondrial permeability transition pore (mPTP) formation. TSPO is found in different species and is expressed at high levels in tissues that synthesize steroids but is also present in other peripheral tissues especially in the heart. TSPO has been involved in the import of cholesterol into mitochondria, a key step in steroidogenesis. This constitutes the main established function of the protein which was recently challenged by genetic studies. TSPO has also been associated directly or indirectly with a wide range of cellular functions such as apoptosis, cell proliferation, differentiation, regulation of mitochondrial function or porphyrin transport. In the heart the role of TSPO remains undefined but a growing body of evidence suggests that TSPO plays a critical role in regulating physiological cardiac function and that TSPO ligands may represent interesting drugs to protect the heart under pathological conditions. This article briefly reviews current knowledge regarding TSPO and discusses its role in the cardiovascular system under physiological and pathologic conditions. More particularly, it provides evidence that TSPO can represent an alternative strategy to develop new pharmacological agents to protect the myocardium against ischemia-reperfusion injury.
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Affiliation(s)
- Didier Morin
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Julien Musman
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Sandrine Pons
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Alain Berdeaux
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Bijan Ghaleh
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
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21
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Zhao AH, Tu LN, Mukai C, Sirivelu MP, Pillai VV, Morohaku K, Cohen R, Selvaraj V. Mitochondrial Translocator Protein (TSPO) Function Is Not Essential for Heme Biosynthesis. J Biol Chem 2015; 291:1591-1603. [PMID: 26627829 DOI: 10.1074/jbc.m115.686360] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Indexed: 01/08/2023] Open
Abstract
Function of the mammalian translocator protein (TSPO; previously known as the peripheral benzodiazepine receptor) remains unclear because its presumed role in steroidogenesis and mitochondrial permeability transition established using pharmacological methods has been refuted in recent genetic studies. Protoporphyrin IX (PPIX) is considered a conserved endogenous ligand for TSPO. In bacteria, TSPO was identified to regulate tetrapyrrole metabolism and chemical catalysis of PPIX in the presence of light, and in vertebrates, TSPO function has been linked to porphyrin transport and heme biosynthesis. Positive correlation between high TSPO expression in cancer cells and susceptibility to photodynamic therapy based on their increased ability to convert the precursor 5-aminolevulinic acid (ALA) to PPIX appeared to reinforce this mechanism. In this study, we used TSPO knock-out (Tspo(-/-)) mice, primary cells, and different tumor cell lines to examine the role of TSPO in erythropoiesis, heme levels, PPIX biosynthesis, phototoxic cell death, and mitochondrial bioenergetic homeostasis. In contrast to expectations, our results demonstrate that TSPO deficiency does not adversely affect erythropoiesis, heme biosynthesis, bioconversion of ALA to PPIX, and porphyrin-mediated phototoxic cell death. TSPO expression levels in cancer cells do not correlate with their ability to convert ALA to PPIX. In fibroblasts, we observed that TSPO deficiency decreased the oxygen consumption rate and mitochondrial membrane potential (ΔΨm) indicative of a cellular metabolic shift, without a negative impact on porphyrin biosynthetic capability. Based on these findings, we conclude that mammalian TSPO does not have a critical physiological function related to PPIX and heme biosynthesis.
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Affiliation(s)
- Amy H Zhao
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Lan N Tu
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Chinatsu Mukai
- the Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, and
| | - Madhu P Sirivelu
- the Department of Clinical Pathology, College of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Viju V Pillai
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Kanako Morohaku
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Roy Cohen
- the Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, and
| | - Vimal Selvaraj
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853,.
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TSPO ligand residence time influences human glioblastoma multiforme cell death/life balance. Apoptosis 2015; 20:383-98. [PMID: 25413799 DOI: 10.1007/s10495-014-1063-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ligands addressed to the mitochondrial Translocator Protein (TSPO) have been suggested as cell death/life and steroidogenesis modulators. Thus, TSPO ligands have been proposed as drug candidates in several diseases; nevertheless, a correlation between their binding affinity and in vitro efficacy has not been demonstrated yet, questioning the specificity of the observed effects. Since drug-target residence time is an emerging parameter able to influence drug pharmacological features, herein, the interaction between TSPO and irDE-MPIGA, a covalent TSPO ligand, was investigated in order to explore TSPO control on death/life processes in a standardized glioblastoma cell setting. After 90 min irDE-MPIGA cell treatment, 25 nM ligand concentration saturated irreversibly all TSPO binding sites; after 24 h, TSPO de-novo synthesis occurred and about 40 % TSPO binding sites resulted covalently bound to irDE-MPIGA. During cell culture treatments, several dynamic events were observed: (a) early apoptotic markers appeared, such as mitochondrial membrane potential collapse (at 3 h) and externalization of phosphatidylserine (at 6 h); (b) cell viability was reduced (at 6 h), without cell cycle arrest. After digitonin-permeabilized cell suspension treatment, a modulation of mitochondrial permeability transition pore was evidenced. Similar effects were elicited by the reversible TSPO ligand PIGA only when applied at micromolar dose. Interestingly, after 6 h, irDE-MPIGA cell exposure restored cell survival parameters. These results highlighted the ligand-target residence time and the cellular setting are crucial parameters that should be taken into account to understand the drug binding affinity and efficacy correlation and, above all, to translate efficiently cellular drug responses from bench to bedside.
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Bernardi P, Rasola A, Forte M, Lippe G. The Mitochondrial Permeability Transition Pore: Channel Formation by F-ATP Synthase, Integration in Signal Transduction, and Role in Pathophysiology. Physiol Rev 2015; 95:1111-55. [PMID: 26269524 DOI: 10.1152/physrev.00001.2015] [Citation(s) in RCA: 420] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The mitochondrial permeability transition (PT) is a permeability increase of the inner mitochondrial membrane mediated by a channel, the permeability transition pore (PTP). After a brief historical introduction, we cover the key regulatory features of the PTP and provide a critical assessment of putative protein components that have been tested by genetic analysis. The discovery that under conditions of oxidative stress the F-ATP synthases of mammals, yeast, and Drosophila can be turned into Ca(2+)-dependent channels, whose electrophysiological properties match those of the corresponding PTPs, opens new perspectives to the field. We discuss structural and functional features of F-ATP synthases that may provide clues to its transition from an energy-conserving into an energy-dissipating device as well as recent advances on signal transduction to the PTP and on its role in cellular pathophysiology.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Andrea Rasola
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Michael Forte
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Giovanna Lippe
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
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Guwiyang Wurra--'Fire Mouse': a global gene knockout model for TSPO/PBR drug development, loss-of-function and mechanisms of compensation studies. Biochem Soc Trans 2015; 43:553-8. [PMID: 26551692 DOI: 10.1042/bst20150039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Indexed: 12/27/2022]
Abstract
The highly conserved 18-kDa translocator protein (TSPO) or peripheral benzodiazepine receptor (PBR), is being investigated as a diagnostic and therapeutic target for disease conditions ranging from inflammation to neurodegeneration and behavioural illnesses. Many functions have been attributed to TSPO/PBR including a role in the mitochondrial permeability transition pore (MPTP), steroidogenesis and energy metabolism. In this review, we detail the recent developments in determining the physiological role of TSPO/PBR, specifically based on data obtained from the recently generated Tspo knockout mouse models. In addition to defining the role of TSPO/PBR, we also describe the value of Tspo knockout mice in determining the selectivity, specificity and presence of any off-target effects of TSPO/PBR ligands.
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Selvaraj V, Stocco DM. The changing landscape in translocator protein (TSPO) function. Trends Endocrinol Metab 2015; 26:341-8. [PMID: 25801473 PMCID: PMC7171652 DOI: 10.1016/j.tem.2015.02.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/11/2015] [Accepted: 02/18/2015] [Indexed: 11/25/2022]
Abstract
Translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor (PBR), is an outer mitochondrial membrane protein. TSPO has been shown to cooperate with steroidogenic acute regulatory protein (StAR) and function in the transport of cholesterol into mitochondria. TSPO has also been considered as a structural component of the mitochondrial permeability transition pore (MPTP). However, recent advances have changed these views of TSPO's functions and have prompted a re-evaluation of established concepts. This review summarizes the history of TSPO, key elements of the debate, and functional experiments that have changed our understanding. Moving forward, we examine how this fundamental change impacts our understanding of TSPO and affects the future of TSPO as a therapeutic and diagnostic target.
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Affiliation(s)
- Vimal Selvaraj
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
| | - Douglas M Stocco
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Lotz C, Kehl F. Volatile Anesthetic-Induced Cardiac Protection: Molecular Mechanisms, Clinical Aspects, and Interactions With Nonvolatile Agents. J Cardiothorac Vasc Anesth 2015; 29:749-60. [DOI: 10.1053/j.jvca.2014.11.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Indexed: 02/07/2023]
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27
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The mitochondrial translocator protein and arrhythmogenesis in ischemic heart disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:234104. [PMID: 25918579 PMCID: PMC4397036 DOI: 10.1155/2015/234104] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/18/2015] [Indexed: 12/19/2022]
Abstract
Mitochondrial dysfunction is a hallmark of multiple cardiovascular disorders, including ischemic heart disease. Although mitochondria are well recognized for their role in energy production and cell death, mechanisms by which they control excitation-contraction coupling, excitability, and arrhythmias are less clear. The translocator protein (TSPO) is an outer mitochondrial membrane protein that is expressed in multiple organ systems. The abundant expression of TSPO in macrophages has been leveraged to image the immune response of the heart to inflammatory processes. More recently, the recognition of TSPO as a regulator of energy-dissipating mitochondrial pathways has extended its utility from a diagnostic marker of inflammation to a therapeutic target influencing diverse pathophysiological processes. Here, we provide an overview of the emerging role of TSPO in ischemic heart disease. We highlight the importance of TSPO in the regenerative process of reactive oxygen species (ROS) induced ROS release through its effects on the inner membrane anion channel (IMAC) and the permeability transition pore (PTP). We discuss evidence implicating TSPO in arrhythmogenesis in the settings of acute ischemia-reperfusion injury and myocardial infarction.
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28
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Bonora M, Wieckowski MR, Chinopoulos C, Kepp O, Kroemer G, Galluzzi L, Pinton P. Molecular mechanisms of cell death: central implication of ATP synthase in mitochondrial permeability transition. Oncogene 2015; 34:1475-86. [PMID: 24727893 DOI: 10.1038/onc.2014.96] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 12/14/2022]
Abstract
The term mitochondrial permeability transition (MPT) is commonly used to indicate an abrupt increase in the permeability of the inner mitochondrial membrane to low molecular weight solutes. Widespread MPT has catastrophic consequences for the cell, de facto marking the boundary between cellular life and death. MPT results indeed in the structural and functional collapse of mitochondria, an event that commits cells to suicide via regulated necrosis or apoptosis. MPT has a central role in the etiology of both acute and chronic diseases characterized by the loss of post-mitotic cells. Moreover, cancer cells are often relatively insensitive to the induction of MPT, underlying their increased resistance to potentially lethal cues. Thus, intense efforts have been dedicated not only at the understanding of MPT in mechanistic terms, but also at the development of pharmacological MPT modulators. In this setting, multiple mitochondrial and extramitochondrial proteins have been suspected to critically regulate the MPT. So far, however, only peptidylprolyl isomerase F (best known as cyclophilin D) appears to constitute a key component of the so-called permeability transition pore complex (PTPC), the supramolecular entity that is believed to mediate MPT. Here, after reviewing the structural and functional features of the PTPC, we summarize recent findings suggesting that another of its core components is represented by the c subunit of mitochondrial ATP synthase.
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Affiliation(s)
- M Bonora
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
| | - M R Wieckowski
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - C Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - O Kepp
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - G Kroemer
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France [4] Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - L Galluzzi
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - P Pinton
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
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Kwong JQ, Molkentin JD. Physiological and pathological roles of the mitochondrial permeability transition pore in the heart. Cell Metab 2015; 21:206-214. [PMID: 25651175 PMCID: PMC4616258 DOI: 10.1016/j.cmet.2014.12.001] [Citation(s) in RCA: 303] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prolonged mitochondrial permeability transition pore (MPTP) opening results in mitochondrial energetic dysfunction, organelle swelling, rupture, and typically a type of necrotic cell death. However, acute opening of the MPTP has a critical physiologic role in regulating mitochondrial Ca(2+) handling and metabolism. Despite the physiological and pathological roles that the MPTP orchestrates, the proteins that comprise the pore itself remain an area of ongoing investigation. Here, we will discuss the molecular composition of the MPTP and its role in regulating cardiac physiology and disease. A better understanding of MPTP structure and function will likely suggest novel cardioprotective therapeutic approaches.
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Affiliation(s)
- Jennifer Q Kwong
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA; Howard Hughes Medical Institute, Cincinnati, OH 45229, USA.
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Bernardi P, Di Lisa F. The mitochondrial permeability transition pore: molecular nature and role as a target in cardioprotection. J Mol Cell Cardiol 2015; 78:100-6. [PMID: 25268651 PMCID: PMC4294587 DOI: 10.1016/j.yjmcc.2014.09.023] [Citation(s) in RCA: 355] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/15/2014] [Accepted: 09/19/2014] [Indexed: 12/18/2022]
Abstract
The mitochondrial permeability transition (PT) - an abrupt increase permeability of the inner membrane to solutes - is a causative event in ischemia-reperfusion injury of the heart, and the focus of intense research in cardioprotection. The PT is due to opening of the PT pore (PTP), a high conductance channel that is critically regulated by a variety of pathophysiological effectors. Very recent work indicates that the PTP forms from the F-ATP synthase, which would switch from an energy-conserving to an energy-dissipating device. This review provides an update on the current debate on how this transition is achieved, and on the PTP as a target for therapeutic intervention. This article is part of a Special Issue entitled "Mitochondria: from basic mitochondrial biology to cardiovascular disease".
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy; Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, 35121 Padova, Italy.
| | - Fabio Di Lisa
- Department of Biomedical Sciences, University of Padova, 35121 Padova, Italy; Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, 35121 Padova, Italy.
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Shoshan-Barmatz V, Ben-Hail D, Admoni L, Krelin Y, Tripathi SS. The mitochondrial voltage-dependent anion channel 1 in tumor cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:2547-75. [PMID: 25448878 DOI: 10.1016/j.bbamem.2014.10.040] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 10/20/2014] [Accepted: 10/24/2014] [Indexed: 02/06/2023]
Abstract
VDAC1 is found at the crossroads of metabolic and survival pathways. VDAC1 controls metabolic cross-talk between mitochondria and the rest of the cell by allowing the influx and efflux of metabolites, ions, nucleotides, Ca2+ and more. The location of VDAC1 at the outer mitochondrial membrane also enables its interaction with proteins that mediate and regulate the integration of mitochondrial functions with cellular activities. As a transporter of metabolites, VDAC1 contributes to the metabolic phenotype of cancer cells. Indeed, this protein is over-expressed in many cancer types, and silencing of VDAC1 expression induces an inhibition of tumor development. At the same time, along with regulating cellular energy production and metabolism, VDAC1 is involved in the process of mitochondria-mediated apoptosis by mediating the release of apoptotic proteins and interacting with anti-apoptotic proteins. The engagement of VDAC1 in the release of apoptotic proteins located in the inter-membranal space involves VDAC1 oligomerization that mediates the release of cytochrome c and AIF to the cytosol, subsequently leading to apoptotic cell death. Apoptosis can also be regulated by VDAC1, serving as an anchor point for mitochondria-interacting proteins, such as hexokinase (HK), Bcl2 and Bcl-xL, some of which are also highly expressed in many cancers. By binding to VDAC1, HK provides both a metabolic benefit and apoptosis-suppressive capacity that offer the cell a proliferative advantage and increase its resistance to chemotherapy. Thus, these and other functions point to VDAC1 as an excellent target for impairing the re-programed metabolism of cancer cells and their ability to evade apoptosis. Here, we review current evidence pointing to the function of VDAC1 in cell life and death, and highlight these functions in relation to both cancer development and therapy. In addressing the recently solved 3D structures of VDAC1, this review will point to structure-function relationships of VDAC as critical for deciphering how this channel can perform such a variety of roles, all of which are important for cell life and death. Finally, this review will also provide insight into VDAC function in Ca2+ homeostasis, protection against oxidative stress, regulation of apoptosis and involvement in several diseases, as well as its role in the action of different drugs. We will discuss the use of VDAC1-based strategies to attack the altered metabolism and apoptosis of cancer cells. These strategies include specific siRNA able to impair energy and metabolic homeostasis, leading to arrested cancer cell growth and tumor development, as well VDAC1-based peptides that interact with anti-apoptotic proteins to induce apoptosis, thereby overcoming the resistance of cancer cell to chemotherapy. Finally, small molecules targeting VDAC1 can induce apoptosis. VDAC1 can thus be considered as standing at the crossroads between mitochondrial metabolite transport and apoptosis and hence represents an emerging cancer drug target. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences, and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - Danya Ben-Hail
- Department of Life Sciences, and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Lee Admoni
- Department of Life Sciences, and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Yakov Krelin
- Department of Life Sciences, and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Shambhoo Sharan Tripathi
- Department of Life Sciences, and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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Stauch KL, Purnell PR, Fox HS. Quantitative proteomics of synaptic and nonsynaptic mitochondria: insights for synaptic mitochondrial vulnerability. J Proteome Res 2014; 13:2620-36. [PMID: 24708184 PMCID: PMC4015687 DOI: 10.1021/pr500295n] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Synaptic mitochondria are essential for maintaining calcium homeostasis and producing ATP, processes vital for neuronal integrity and synaptic transmission. Synaptic mitochondria exhibit increased oxidative damage during aging and are more vulnerable to calcium insult than nonsynaptic mitochondria. Why synaptic mitochondria are specifically more susceptible to cumulative damage remains to be determined. In this study, the generation of a super-SILAC mix that served as an appropriate internal standard for mouse brain mitochondria mass spectrometry based analysis allowed for the quantification of the proteomic differences between synaptic and nonsynaptic mitochondria isolated from 10-month-old mice. We identified a total of 2260 common proteins between synaptic and nonsynaptic mitochondria of which 1629 were annotated as mitochondrial. Quantitative proteomic analysis of the proteins common between synaptic and nonsynaptic mitochondria revealed significant differential expression of 522 proteins involved in several pathways including oxidative phosphorylation, mitochondrial fission/fusion, calcium transport, and mitochondrial DNA replication and maintenance. In comparison to nonsynaptic mitochondria, synaptic mitochondria exhibited increased age-associated mitochondrial DNA deletions and decreased bioenergetic function. These findings provide insights into synaptic mitochondrial susceptibility to damage.
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Affiliation(s)
- Kelly L Stauch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center , 985800 Nebraska Medical Center, Omaha, Nebraska 68198, United States
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Šileikytė J, Blachly-Dyson E, Sewell R, Carpi A, Menabò R, Di Lisa F, Ricchelli F, Bernardi P, Forte M. Regulation of the mitochondrial permeability transition pore by the outer membrane does not involve the peripheral benzodiazepine receptor (Translocator Protein of 18 kDa (TSPO)). J Biol Chem 2014; 289:13769-81. [PMID: 24692541 DOI: 10.1074/jbc.m114.549634] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Translocator protein of 18 kDa (TSPO) is a highly conserved, ubiquitous protein localized in the outer mitochondrial membrane, where it is thought to play a key role in the mitochondrial transport of cholesterol, a key step in the generation of steroid hormones. However, it was first characterized as the peripheral benzodiazepine receptor because it appears to be responsible for high affinity binding of a number of benzodiazepines to non-neuronal tissues. Ensuing studies have employed natural and synthetic ligands to assess the role of TSPO function in a number of natural and pathological circumstances. Largely through the use of these compounds and biochemical associations, TSPO has been proposed to play a role in the mitochondrial permeability transition pore (PTP), which has been associated with cell death in many human pathological conditions. Here, we critically assess the role of TSPO in the function of the PTP through the generation of mice in which the Tspo gene has been conditionally eliminated. Our results show that 1) TSPO plays no role in the regulation or structure of the PTP, 2) endogenous and synthetic ligands of TSPO do not regulate PTP activity through TSPO, 3) outer mitochondrial membrane regulation of PTP activity occurs though a mechanism that does not require TSPO, and 4) hearts lacking TSPO are as sensitive to ischemia-reperfusion injury as hearts from control mice. These results call into question a wide variety of studies implicating TSPO in a number of pathological processes through its actions on the PTP.
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Affiliation(s)
- Justina Šileikytė
- From the Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, I-35121 Padova, Italy
| | | | - Randall Sewell
- the Vollum Institute, Oregon Health and Sciences University, Portland, Oregon 97239, and
| | - Andrea Carpi
- From the Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, I-35121 Padova, Italy
| | - Roberta Menabò
- From the Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, I-35121 Padova, Italy
| | - Fabio Di Lisa
- From the Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, I-35121 Padova, Italy
| | - Fernanda Ricchelli
- the Consiglio Nazionale delle Ricerche Institute of Biomedical Technologies at the Department of Biology, University of Padova, I-35121 Padova, Italy
| | - Paolo Bernardi
- From the Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, I-35121 Padova, Italy,
| | - Michael Forte
- the Vollum Institute, Oregon Health and Sciences University, Portland, Oregon 97239, and
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Sripetchwandee J, Pipatpiboon N, Chattipakorn N, Chattipakorn S. Combined therapy of iron chelator and antioxidant completely restores brain dysfunction induced by iron toxicity. PLoS One 2014; 9:e85115. [PMID: 24400127 PMCID: PMC3882264 DOI: 10.1371/journal.pone.0085115] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 12/02/2013] [Indexed: 12/25/2022] Open
Abstract
Background Excessive iron accumulation leads to iron toxicity in the brain; however the underlying mechanism is unclear. We investigated the effects of iron overload induced by high iron-diet consumption on brain mitochondrial function, brain synaptic plasticity and learning and memory. Iron chelator (deferiprone) and antioxidant (n-acetyl cysteine) effects on iron-overload brains were also studied. Methodology Male Wistar rats were fed either normal diet or high iron-diet consumption for 12 weeks, after which rats in each diet group were treated with vehicle or deferiprone (50 mg/kg) or n-acetyl cysteine (100 mg/kg) or both for another 4 weeks. High iron-diet consumption caused brain iron accumulation, brain mitochondrial dysfunction, impaired brain synaptic plasticity and cognition, blood-brain-barrier breakdown, and brain apoptosis. Although both iron chelator and antioxidant attenuated these deleterious effects, combined therapy provided more robust results. Conclusion In conclusion, this is the first study demonstrating that combined iron chelator and anti-oxidant therapy completely restored brain function impaired by iron overload.
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Affiliation(s)
- Jirapas Sripetchwandee
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Noppamas Pipatpiboon
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- * E-mail:
| | - Siriporn Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Department of Oral Biology and Diagnostic Science, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
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Sripetchwandee J, Sanit J, Chattipakorn N, Chattipakorn SC. Mitochondrial calcium uniporter blocker effectively prevents brain mitochondrial dysfunction caused by iron overload. Life Sci 2013; 92:298-304. [PMID: 23333832 DOI: 10.1016/j.lfs.2013.01.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 12/22/2012] [Accepted: 01/02/2013] [Indexed: 12/12/2022]
Abstract
AIMS Although iron overload induces oxidative stress and brain mitochondrial dysfunction, and is associated with neurodegenerative diseases, brain mitochondrial iron uptake has not been investigated. We determined the role of mitochondrial calcium uniporter (MCU) in brain mitochondria as a major route for iron entry. We hypothesized that iron overload causes brain mitochondrial dysfunction, and that the MCU blocker prevents iron entry into mitochondria, thus attenuating mitochondrial dysfunction. MAIN METHODS Isolated brain mitochondria from male Wistar rats were used. Iron (Fe(2+) and Fe(3+)) at 0-286 μM were applied onto mitochondria at various incubation times (5-30 min), and the mitochondrial function was determined. Effects of MCU blocker (Ru-360) and iron chelator were studied. KEY FINDINGS Both Fe(2+) and Fe(3+) entered brain mitochondria and caused mitochondrial swelling in a dose- and time-dependent manner, and caused mitochondrial depolarization and increased ROS production. However, Fe(2+) caused more severe mitochondrial dysfunction than Fe(3+). Although all drugs attenuated mitochondrial dysfunction caused by iron overload, only an MCU blocker could completely prevent ROS production and mitochondrial depolarization. SIGNIFICANCE Our findings indicated that iron overload caused brain mitochondrial dysfunction, and that an MCU blocker effectively prevented this impairment, suggesting that MCU could be the major portal for brain mitochondrial iron uptake.
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Affiliation(s)
- Jirapas Sripetchwandee
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Jung M, Metzger D. Purkinje-neuron-specific down-regulation of p38 protects motoric function from the repeated use of benzodiazepine. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/abb.2013.46a009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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38
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Mitochondrial calcium uniporter blocker prevents cardiac mitochondrial dysfunction induced by iron overload in thalassemic mice. Biometals 2012; 25:1167-75. [DOI: 10.1007/s10534-012-9579-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/14/2012] [Indexed: 10/28/2022]
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Calcium-induced Cardiac Mitochondrial Dysfunction Is Predominantly Mediated by Cyclosporine A-dependent Mitochondrial Permeability Transition Pore. Arch Med Res 2012; 43:333-8. [DOI: 10.1016/j.arcmed.2012.06.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 06/06/2012] [Indexed: 12/17/2022]
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40
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Yarana C, Sanit J, Chattipakorn N, Chattipakorn S. Synaptic and nonsynaptic mitochondria demonstrate a different degree of calcium-induced mitochondrial dysfunction. Life Sci 2012; 90:808-14. [DOI: 10.1016/j.lfs.2012.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 04/04/2012] [Accepted: 04/05/2012] [Indexed: 10/28/2022]
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Gouriou Y, Demaurex N, Bijlenga P, De Marchi U. Mitochondrial calcium handling during ischemia-induced cell death in neurons. Biochimie 2011; 93:2060-7. [PMID: 21846486 DOI: 10.1016/j.biochi.2011.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 08/03/2011] [Indexed: 12/18/2022]
Abstract
Mitochondria sense and shape cytosolic Ca(2+) signals by taking up and subsequently releasing Ca(2+) ions during physiological and pathological Ca(2+) elevations. Sustained elevations in the mitochondrial matrix Ca(2+) concentration are increasingly recognized as a defining feature of the intracellular cascade of lethal events that occur in neurons during cerebral ischemia. Here, we review the recently identified transport proteins that mediate the fluxes of Ca(2+) across mitochondria and discuss the implication of the permeability transition pore in decoding the abnormally sustained mitochondrial Ca(2+) elevations that occur during cerebral ischemia.
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Affiliation(s)
- Yves Gouriou
- Department of Cell Physiology and Metabolism, University of Geneva, rue Michel-Servet 1, Genève, Switzerland
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42
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Surinkaew S, Chattipakorn S, Chattipakorn N. Roles of mitochondrial benzodiazepine receptor in the heart. Can J Cardiol 2011; 27:262.e3 -13. [PMID: 21459278 DOI: 10.1016/j.cjca.2010.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 06/02/2010] [Indexed: 12/01/2022] Open
Abstract
Mitochondrial benzodiazepine receptor (mBzR) is a type of peripheral benzodiazepine receptor that is located in the outer membrane of mitochondria. It is an 18-kDa protein that can form a multimeric complex with voltage-dependent anion channel (32 kDa) and adenine nucleotide translocator (30 kDa). mBzR is found in various species and abundantly distributed in peripheral tissues, including the cardiovascular system. The mitochondria are well known as the site of energy production, and the heart is the organ that highly requires this energy supply. In the past decades, it has been shown that mBzR plays a critical role in regulating mitochondrial and heart functions. A growing body of evidence demonstrates that mBzR is associated with regulation of mitochondrial respiration, mitochondrial membrane potential, apoptosis, and reactive oxygen species production. Moreover, mBzR has been suggested to play a role in alteration of physiological effects in the heart such as contractility and heart rate. mBzR is involved in the pathologic condition such as ischemia/reperfusion injury, responses to stress, and changes in electrophysiological properties and arrhythmogenesis. In this review, evidence of the roles of mBzR in the heart under both physiological and pathologic conditions is presented. Clinical studies regarding the use of pharmacologic intervention involving mBzR in the heart are also discussed as a possible target for the treatment of electrical and mechanical dysfunction in the heart.
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Affiliation(s)
- Sirirat Surinkaew
- Department of Physiology, Chiang Mai University, Chiang Mai, Thailand
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43
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Granulocyte-colony stimulating factor attenuates mitochondrial dysfunction induced by oxidative stress in cardiac mitochondria. Mitochondrion 2011; 11:457-66. [DOI: 10.1016/j.mito.2011.01.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 11/30/2010] [Accepted: 01/24/2011] [Indexed: 12/22/2022]
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King SR, Stocco DM. Steroidogenic acute regulatory protein expression in the central nervous system. Front Endocrinol (Lausanne) 2011; 2:72. [PMID: 22649383 PMCID: PMC3355896 DOI: 10.3389/fendo.2011.00072] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/24/2011] [Indexed: 11/13/2022] Open
Abstract
Locally produced neurosteroids are proposed to have many functions in the central nervous system. The identification of the steroidogenic acute regulatory protein in steroid-producing neural cells provides a new tool to understand the sites, regulation, and importance of their synthesis.
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Affiliation(s)
- Steven R. King
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, TX, USA
| | - Douglas M. Stocco
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, TX, USA
- *Correspondence: Douglas M. Stocco, Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA. e-mail:
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Sileikyte J, Petronilli V, Zulian A, Dabbeni-Sala F, Tognon G, Nikolov P, Bernardi P, Ricchelli F. Regulation of the inner membrane mitochondrial permeability transition by the outer membrane translocator protein (peripheral benzodiazepine receptor). J Biol Chem 2010; 286:1046-53. [PMID: 21062740 DOI: 10.1074/jbc.m110.172486] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We studied the properties of the permeability transition pore (PTP) in rat liver mitochondria and in mitoplasts retaining inner membrane ultrastructure and energy-linked functions. Like mitochondria, mitoplasts readily underwent a permeability transition following Ca(2+) uptake in a process that maintained sensitivity to cyclosporin A. On the other hand, major differences between mitochondria and mitoplasts emerged in PTP regulation by ligands of the outer membrane translocator protein of 18 kDa, TSPO, formerly known as the peripheral benzodiazepine receptor. Indeed, (i) in mitoplasts, the PTP could not be activated by photo-oxidation after treatment with dicarboxylic porphyrins endowed with protoporphyrin IX configuration, which bind TSPO in intact mitochondria; and (ii) mitoplasts became resistant to the PTP-inducing effects of N,N-dihexyl-2-(4-fluorophenyl)indole-3-acetamide and of other selective ligands of TSPO. Thus, the permeability transition is an inner membrane event that is regulated by the outer membrane through specific interactions with TSPO.
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Affiliation(s)
- Justina Sileikyte
- Department of Biomedical Sciences, Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of Padova, I-35121 Padova, Italy
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Leducq-Alet N, Vin V, Savi P, Bono F. TNF-alpha induced PMN apoptosis in whole human blood: Protective effect of SSR180575, a potent and selective peripheral benzodiazepine ligand. Biochem Biophys Res Commun 2010; 399:475-9. [DOI: 10.1016/j.bbrc.2010.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 07/03/2010] [Indexed: 10/19/2022]
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47
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A pore way to die: the role of mitochondria in reperfusion injury and cardioprotection. Biochem Soc Trans 2010; 38:841-60. [DOI: 10.1042/bst0380841] [Citation(s) in RCA: 238] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In addition to their normal physiological role in ATP production and metabolism, mitochondria exhibit a dark side mediated by the opening of a non-specific pore in the inner mitochondrial membrane. This mitochondrial permeability transition pore (MPTP) causes the mitochondria to breakdown rather than synthesize ATP and, if unrestrained, leads to necrotic cell death. The MPTP is opened in response to Ca2+ overload, especially when accompanied by oxidative stress, elevated phosphate concentration and adenine nucleotide depletion. These conditions are experienced by the heart and brain subjected to reperfusion after a period of ischaemia as may occur during treatment of a myocardial infarction or stroke and during heart surgery. In the present article, I review the properties, regulation and molecular composition of the MPTP. The evidence for the roles of CyP-D (cyclophilin D), the adenine nucleotide translocase and the phosphate carrier are summarized and other potential interactions with outer mitochondrial membrane proteins are discussed. I then review the evidence that MPTP opening mediates cardiac reperfusion injury and that MPTP inhibition is cardioprotective. Inhibition may involve direct pharmacological targeting of the MPTP, such as with cyclosporin A that binds to CyP-D, or indirect inhibition of MPTP opening such as with preconditioning protocols. These invoke complex signalling pathways to reduce oxidative stress and Ca2+ load. MPTP inhibition also protects against congestive heart failure in hypertensive animal models. Thus the MPTP is a very promising pharmacological target for clinical practice, especially once more specific drugs are developed.
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Martín A, Boisgard R, Thézé B, Van Camp N, Kuhnast B, Damont A, Kassiou M, Dollé F, Tavitian B. Evaluation of the PBR/TSPO radioligand [(18)F]DPA-714 in a rat model of focal cerebral ischemia. J Cereb Blood Flow Metab 2010; 30:230-41. [PMID: 19794397 PMCID: PMC2949091 DOI: 10.1038/jcbfm.2009.205] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 09/02/2009] [Accepted: 09/06/2009] [Indexed: 12/23/2022]
Abstract
Focal cerebral ischemia leads to an inflammatory reaction involving an overexpression of the peripheral benzodiazepine receptor (PBR)/18-kDa translocator protein (TSPO) in the cerebral monocytic lineage (microglia and monocyte) and in astrocytes. Imaging of PBR/TSPO by positron emission tomography (PET) using radiolabeled ligands can document inflammatory processes induced by cerebral ischemia. We performed in vivo PET imaging with [(18)F]DPA-714 to determine the time course of PBR/TSPO expression over several days after induction of cerebral ischemia in rats. In vivo PET imaging showed significant increase in DPA (N,N-diethyl-2-(2-(4-(2-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide) uptake on the injured side compared with that in the contralateral area on days 7, 11, 15, and 21 after ischemia; the maximal binding value was reached 11 days after ischemia. In vitro autoradiography confirmed these in vivo results. In vivo and in vitro [(18)F]DPA-714 binding was displaced from the lesion by PK11195 and DPA-714. Immunohistochemistry showed increased PBR/TSPO expression, peaking at day 11 in cells expressing microglia/macrophage antigens in the ischemic area. At later times, a centripetal migration of astrocytes toward the lesion was observed, promoting the formation of an astrocytic scar. These results show that [(18)F]DPA-714 provides accurate quantitative information of the time course of PBR/TSPO expression in experimental stroke.
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Affiliation(s)
- Abraham Martín
- INSERM U803, Orsay, France
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
| | - Raphaël Boisgard
- INSERM U803, Orsay, France
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
| | - Benoit Thézé
- INSERM U803, Orsay, France
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
| | - Nadja Van Camp
- INSERM U803, Orsay, France
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
| | - Bertrand Kuhnast
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
| | - Annelaure Damont
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
| | - Michael Kassiou
- University of Sydney, Sydney, New South Wales, Australia
- Discipline of Medical Radiation Sciences, University of Sydney, Sydney, New South Wales, Australia
- School of Chemistry, University of Sydney, Sydney, New South Wales, Australia
| | - Frédéric Dollé
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
| | - Bertrand Tavitian
- INSERM U803, Orsay, France
- CEA, DSV, FBM, SHFJ, Laboratoire Imagerie Moléculaire Expérimentale, Orsay, France
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Buckingham SD, Higashino Y, Sattelle DB. Allosteric modulation by benzodiazepines of GABA-gated chloride channels of an identified insect motor neurone. INVERTEBRATE NEUROSCIENCE 2009; 9:85-9. [PMID: 19847463 DOI: 10.1007/s10158-009-0091-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 09/18/2009] [Indexed: 02/05/2023]
Abstract
The actions of benzodiazepines were studied on the responses to GABA of the fast coxal depressor (D(f)) motor neurone of the cockroach, Periplaneta americana. Ro5-4864, diazepam and clonazepam were investigated. Responses to GABA receptors were enhanced by both Ro5-4864 and diazepam, whereas clonazepam, a potent-positive allosteric modulator of human GABA(A) receptors, was ineffective on the native insect GABA receptors of the D(f) motor neurone. Thus, clear pharmacological differences exist between insect and mammalian native GABA-gated chloride channels with respect to the actions of benzodiazepines. The results enhance our understanding of invertebrate GABA-gated chloride channels which have recently proved important in (a) comparative studies aimed at identifying human allosteric drug-binding sites and (b) understanding the actions of compounds used to control ectoparasites and insect crop pests.
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Affiliation(s)
- Steven D Buckingham
- MRC Functional Genomics Unit, Department of Physiology Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
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Mazurika C, Veenman L, Weizman R, Bidder M, Leschiner S, Golani I, Spanier I, Weisinger G, Gavish M. Estradiol modulates uterine 18 kDa translocator protein gene expression in uterus and kidney of rats. Mol Cell Endocrinol 2009; 307:43-9. [PMID: 19524125 DOI: 10.1016/j.mce.2009.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 03/30/2009] [Accepted: 04/02/2009] [Indexed: 11/19/2022]
Abstract
We examined the effect of ovariectomy, with and without estradiol treatment, on 18 kDa translocator protein (TSPO) gene expression and its binding density in the uterus and kidney of rats. Ovariectomy causes a significant decrease in uterine, but not renal TSPO binding density, while estradiol treatment of ovariectomized rats restored TSPO binding density in the uterus. These TSPO density levels did not correlate with steady state or new RNA transcription. Our in vivo study suggests that estradiol is responsible for the maintenance of uterine TSPO density via transcriptional mechanisms. Our in vivo study also suggests that in the kidney estradiol appears to operate via post-transcriptional mechanisms to maintain TSPO density.
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Affiliation(s)
- Caroline Mazurika
- Department of Molecular Pharmacology, the Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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