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Peng Y, Jin H, Xue YH, Chen Q, Yao SY, Du MQ, Liu S. Current and future therapeutic strategies for Alzheimer's disease: an overview of drug development bottlenecks. Front Aging Neurosci 2023; 15:1206572. [PMID: 37600514 PMCID: PMC10438465 DOI: 10.3389/fnagi.2023.1206572] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/10/2023] [Indexed: 08/22/2023] Open
Abstract
Alzheimer's disease (AD) is the most common chronic neurodegenerative disease worldwide. It causes cognitive dysfunction, such as aphasia and agnosia, and mental symptoms, such as behavioral abnormalities; all of which place a significant psychological and economic burden on the patients' families. No specific drugs are currently available for the treatment of AD, and the current drugs for AD only delay disease onset and progression. The pathophysiological basis of AD involves abnormal deposition of beta-amyloid protein (Aβ), abnormal tau protein phosphorylation, decreased activity of acetylcholine content, glutamate toxicity, autophagy, inflammatory reactions, mitochondria-targeting, and multi-targets. The US Food and Drug Administration (FDA) has approved five drugs for clinical use: tacrine, donepezil, carbalatine, galantamine, memantine, and lecanemab. We have focused on the newer drugs that have undergone clinical trials, most of which have not been successful as a result of excessive clinical side effects or poor efficacy. Although aducanumab received rapid approval from the FDA on 7 June 2021, its long-term safety and tolerability require further monitoring and confirmation. In this literature review, we aimed to explore the possible pathophysiological mechanisms underlying the occurrence and development of AD. We focused on anti-Aβ and anti-tau drugs, mitochondria-targeting and multi-targets, commercially available drugs, bottlenecks encountered in drug development, and the possible targets and therapeutic strategies for future drug development. We hope to present new concepts and methods for future drug therapies for AD.
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Affiliation(s)
- Yong Peng
- Neurology Department, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- Neurology Department, The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Hong Jin
- Neurology Department, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- Neurology Department, The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Ya-hui Xue
- Neurology Department, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- Neurology Department, The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Quan Chen
- Neurology Department, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- Neurology Department, The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Shun-yu Yao
- Neurology Department, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- Neurology Department, The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Miao-qiao Du
- Neurology Department, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- Neurology Department, The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Shu Liu
- Neurology Department, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- Neurology Department, The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
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Steidemann MM, Liu J, Bayes K, Castro LP, Ferguson-Miller S, LaPres JJ. Evidence for crosstalk between the aryl hydrocarbon receptor and the translocator protein in mouse lung epithelial cells. Exp Cell Res 2023; 429:113617. [PMID: 37172753 DOI: 10.1016/j.yexcr.2023.113617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 04/07/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Cellular homeostasis requires the use of multiple environmental sensors that can respond to a variety of endogenous and exogenous compounds. The aryl hydrocarbon receptor (AHR) is classically known as a transcription factor that induces drug metabolizing enzymes when bound to toxicants such as 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD). The receptor has a growing number of putative endogenous ligands, such as tryptophan, cholesterol, and heme metabolites. Many of these compounds are also linked to the translocator protein (TSPO), an outer mitochondrial membrane protein. Given a portion of the cellular pool of the AHR has also been localized to mitochondria and the overlap in putative ligands, we tested the hypothesis that crosstalk exists between the two proteins. CRISPR/Cas9 was used to create knockouts for AHR and TSPO in a mouse lung epithelial cell line (MLE-12). WT, AHR-/-, and TSPO-/- cells were then exposed to AHR ligand (TCDD), TSPO ligand (PK11195), or both and RNA-seq was performed. More mitochondrial-related genes were altered by loss of both AHR and TSPO than would have been expected just by chance. Some of the genes altered included those that encode for components of the electron transport system and the mitochondrial calcium uniporter. Both proteins altered the activity of the other as AHR loss caused the increase of TSPO at both the mRNA and protein level and loss of TSPO significantly increased the expression of classic AHR battery genes after TCDD treatment. This research provides evidence that AHR and TSPO participate in similar pathways that contribute to mitochondrial homeostasis.
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Affiliation(s)
- Michelle M Steidemann
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - Kalin Bayes
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - Lizbeth P Castro
- Department of Cell and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - John J LaPres
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States.
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Baburina YL, Zvyagina AI, Odinokova IV, Krestinina OV. [Effect of erastin and G3139 on rat liver mitochondria in chronic alcoholic intoxication]. BIOMEDITSINSKAIA KHIMIIA 2023; 69:62-71. [PMID: 36857428 DOI: 10.18097/pbmc20236901062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
The effect of modulators of VDAC channels - G3139 and erastin on the mitochondrial permeability transition pore (mPTP) functioning and changes in the content of proteins involved in regulation of mPTP (VDAC, CNPase, and TSPO) has been investigated in liver mitochondria of rats with chronic alcohol intoxication. It was shown that the mitochondria of rats treated with ethanol were more sensitive to mPTP induction. Moreover, ethanol induced changes in the expression of mPTP regulator proteins. G3139 and erastin were also able to influence the studied mitochondrial parameters, and they increased their effect in the liver mitochondria of rats treated with ethanol, as compared to the mitochondria of control rats. We hypothesize that the results of this study may help to elucidate the mechanisms of chronic action of ethanol on mitochondria and contribute to the development of new therapeutic strategies for treating the consequences of ethanol-related diseases.
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Affiliation(s)
- Yu L Baburina
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
| | - A I Zvyagina
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
| | - I V Odinokova
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
| | - O V Krestinina
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Science, Pushchino, Russia
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Carbenoxolon Is Capable to Regulate the Mitochondrial Permeability Transition Pore Opening in Chronic Alcohol Intoxication. Int J Mol Sci 2021; 22:ijms221910249. [PMID: 34638588 PMCID: PMC8549702 DOI: 10.3390/ijms221910249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/15/2021] [Accepted: 09/21/2021] [Indexed: 11/25/2022] Open
Abstract
Background: carbenoxolone, which is a derivative of glyceretic acid, is actively used in pharmacology for the treatment of diseases of various etiologies. In addition, we have shown carbenoxolone as an effective inducer of mitochondrial permeability transition pore in rat brain and liver mitochondria. Methods: in the course of this work, comparative studies were carried out on the effect of carbenoxolone on the parameters of mPTP functioning in mitochondria isolated from the liver of control and alcoholic rats. Results: within the framework of this work, it was found that carbenoxolone significantly increased its effect in the liver mitochondria of rats with chronic intoxication. In particular, this was expressed in a reduction in the lag phase, a decrease in the threshold calcium concentration required to open a pore, an acceleration of high-amplitude cyclosporin-sensitive swelling of mitochondria, as well as an increase in the effect of carbenoxolone on the level of mitochondrial membrane-bound proteins. Thus, as a result of the studies carried out, it was shown that carbenoxolone is involved in the development/modulation of alcohol tolerance and dependence in rats.
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Song N, Yang M, Zhang H, Yang SK. Intracellular Calcium Homeostasis and Kidney Disease. Curr Med Chem 2021; 28:3647-3665. [PMID: 33138745 DOI: 10.2174/0929867327666201102114257] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/30/2020] [Accepted: 09/30/2020] [Indexed: 11/22/2022]
Abstract
Kidney disease is a serious health problem that burdens our healthcare system. It is crucial to find the accurate pathogenesis of various types of kidney disease to provide guidance for precise therapies for patients suffering from these diseases. However, the exact molecular mechanisms underlying these diseases have not been fully understood. Disturbance of calcium homeostasis in renal cells plays a fundamental role in the development of various types of kidney disease, such as primary glomerular disease, diabetic nephropathy, acute kidney injury and polycystic kidney disease, through promoting cell proliferation, stimulating extracellular matrix accumulation, aggravating podocyte injury, disrupting cellular energetics as well as dysregulating cell survival and death dynamics. As a result, preventing the disturbance of calcium homeostasis in specific renal cells (such as tubular cells, podocytes and mesangial cells) is becoming one of the most promising therapeutic strategies in the treatment of kidney disease. The endoplasmic reticulum and mitochondria are two vital organelles in this process. Calcium ions cycle between the endoplasmic reticulum and mitochondria at the conjugation of these two organelles known as the mitochondria-associated endoplasmic reticulum membrane, maintaining calcium homeostasis. The pharmacologic modulation of cellular calcium homeostasis can be viewed as a novel therapeutic method for renal diseases. Here, we will introduce calcium homeostasis under physiological conditions and the disturbance of calcium homeostasis in kidney diseases. We will focus on the calcium homeostasis regulation in renal cells (including tubular cells, podocytes and mesangial cells), especially in the mitochondria- associated endoplasmic reticulum membranes of these renal cells.
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Affiliation(s)
- Na Song
- Department of Nephrology, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, China
| | - Ming Yang
- Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan Province, China
| | - Hao Zhang
- Department of Nephrology, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, China
| | - Shi-Kun Yang
- Department of Nephrology, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, China
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Seidlmayer LK, Hanson BJ, Thai PN, Schaefer S, Bers DM, Dedkova EN. PK11195 Protects From Cell Death Only When Applied During Reperfusion: Succinate-Mediated Mechanism of Action. Front Physiol 2021; 12:628508. [PMID: 34149440 PMCID: PMC8212865 DOI: 10.3389/fphys.2021.628508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/28/2021] [Indexed: 11/13/2022] Open
Abstract
Aim: Reperfusion after myocardial ischemia causes cellular injury, in part due to changes in mitochondrial Ca2+ handling, oxidative stress, and myocyte energetics. We have previously shown that the 18-kDa translocator protein of the outer mitochondrial membrane (TSPO) can modulate Ca2+ handling. Here, we aim to evaluate the role of the TSPO in ischemia/reperfusion (I/R) injury. Methods: Rabbit ventricular myocytes underwent simulated acute ischemia (20 min) and reperfusion (at 15 min, 1 h, and 3 h) in the absence and presence of 50 μM PK11195, a TSPO inhibitor. Cell death was measured by lactate dehydrogenase (LDH) assay, while changes in mitochondrial Ca2+, membrane potential (ΔΨm), and reactive oxygen species (ROS) generation were monitored using confocal microscopy in combination with fluorescent indicators. Substrate utilization was measured with Biolog mitochondrial plates. Results: Cell death was increased by ~200% following I/R compared to control untreated ventricular myocytes. Incubation with 50 μM PK11195 during both ischemia and reperfusion did not reduce cell death but increased mitochondrial Ca2+ uptake and ROS generation. However, application of 50 μM PK11195 only at the onset and during reperfusion effectively protected against cell death. The large-scale oscillations in ΔΨm observed after ~1 h of reperfusion were significantly delayed by 1 μM cyclosporin A and almost completely prevented by 50 μM PK11195 applied during 3 h of reperfusion. After an initial increase, mitochondrial Ca2+, measured with Myticam, rapidly declined during 3 h of reperfusion after the initial transient increase. This decline was prevented by application of PK11195 at the onset and during reperfusion. PK11195 prevented a significant increase in succinate utilization following I/R and succinate-induced forward-mode ROS generation. Treatment with PK11195 was also associated with a significant increase in glutamate and a decrease in leucine utilization. Conclusion: PK11195 administered specifically at the moment of reperfusion limited ROS-induced ROS release and cell death, likely in part, by a shift from succinate to glutamate utilization. These data demonstrate a unique mechanism to limit cardiac injury after I/R.
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Affiliation(s)
- Lea K Seidlmayer
- Department of Cardiology, University Hospital Olbenburg, Olbenburg, Germany
| | - Benjamin J Hanson
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Phung N Thai
- Department of Internal Medicine, Division of Cardiovascular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Saul Schaefer
- Department of Internal Medicine, Division of Cardiovascular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Donald M Bers
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Elena N Dedkova
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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Cui Y, Pan M, Ma J, Song X, Cao W, Zhang P. Recent progress in the use of mitochondrial membrane permeability transition pore in mitochondrial dysfunction-related disease therapies. Mol Cell Biochem 2021; 476:493-506. [PMID: 33000352 DOI: 10.1007/s11010-020-03926-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/23/2020] [Indexed: 12/13/2022]
Abstract
Mitochondria have various cellular functions, including ATP synthesis, calcium homeostasis, cell senescence, and death. Mitochondrial dysfunction has been identified in a variety of disorders correlated with human health. Among the many underlying mechanisms of mitochondrial dysfunction, the opening up of the mitochondrial permeability transition pore (mPTP) is one that has drawn increasing interest in recent years. It plays an important role in apoptosis and necrosis; however, the molecular structure and function of the mPTP have still not been fully elucidated. In recent years, the abnormal opening up of the mPTP has been implicated in the development and pathogenesis of diverse diseases including ischemia/reperfusion injury (IRI), neurodegenerative disorders, tumors, and chronic obstructive pulmonary disease (COPD). This review provides a systematic introduction to the possible molecular makeup of the mPTP and summarizes the mitochondrial dysfunction-correlated diseases and highlights possible underlying mechanisms. Since the mPTP is an important target in mitochondrial dysfunction, this review also summarizes potential treatments, which may be used to inhibit pore opening up via the molecules composing mPTP complexes, thus suppressing the progression of mitochondrial dysfunction-related diseases.
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Affiliation(s)
- Yuting Cui
- School of Life Science, Shandong University of Technology, Zibo, Shandong Province, China
| | - Mingyue Pan
- Department of Pharmacy, Shenzhen Luohu People's Hospital, Shenzhen, Guangdong Province, China
| | - Jing Ma
- The Eighth Affiliated Hospital, Sun Yat-Sen University, Shenzhen, Guangdong Province, China
| | - Xinhua Song
- School of Life Science, Shandong University of Technology, Zibo, Shandong Province, China
| | - Weiling Cao
- Department of Pharmacy, Shenzhen Luohu People's Hospital, Shenzhen, Guangdong Province, China.
| | - Peng Zhang
- Department of Pharmacy, Shenzhen Luohu People's Hospital, Shenzhen, Guangdong Province, China.
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Shoshan-Barmatz V, Shteinfer-Kuzmine A, Verma A. VDAC1 at the Intersection of Cell Metabolism, Apoptosis, and Diseases. Biomolecules 2020; 10:E1485. [PMID: 33114780 PMCID: PMC7693975 DOI: 10.3390/biom10111485] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/02/2020] [Accepted: 10/22/2020] [Indexed: 02/07/2023] Open
Abstract
The voltage-dependent anion channel 1 (VDAC1) protein, is an important regulator of mitochondrial function, and serves as a mitochondrial gatekeeper, with responsibility for cellular fate. In addition to control over energy sources and metabolism, the protein also regulates epigenomic elements and apoptosis via mediating the release of apoptotic proteins from the mitochondria. Apoptotic and pathological conditions, as well as certain viruses, induce cell death by inducing VDAC1 overexpression leading to oligomerization, and the formation of a large channel within the VDAC1 homo-oligomer. This then permits the release of pro-apoptotic proteins from the mitochondria and subsequent apoptosis. Mitochondrial DNA can also be released through this channel, which triggers type-Ι interferon responses. VDAC1 also participates in endoplasmic reticulum (ER)-mitochondria cross-talk, and in the regulation of autophagy, and inflammation. Its location in the outer mitochondrial membrane, makes VDAC1 ideally placed to interact with over 100 proteins, and to orchestrate the interaction of mitochondrial and cellular activities through a number of signaling pathways. Here, we provide insights into the multiple functions of VDAC1 and describe its involvement in several diseases, which demonstrate the potential of this protein as a druggable target in a wide variety of pathologies, including cancer.
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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; (A.S.-K.); (A.V.)
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A systematic review of post-translational modifications in the mitochondrial permeability transition pore complex associated with cardiac diseases. Biochim Biophys Acta Mol Basis Dis 2020; 1867:165992. [PMID: 33091565 DOI: 10.1016/j.bbadis.2020.165992] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/23/2020] [Accepted: 10/08/2020] [Indexed: 12/28/2022]
Abstract
The mitochondrial permeability transition pore (mPTP) opening is involved in the pathophysiology of multiple cardiac diseases, such as ischemia/reperfusion injury and heart failure. A growing number of evidence provided by proteomic screening techniques has demonstrated the role of post-translational modifications (PTMs) in several key components of the pore in response to changes in the extra/intracellular environment and bioenergetic demand. This could lead to a fine, complex regulatory mechanism that, under pathological conditions, can shift the state of mitochondrial functions and, thus, the cell's fate. Understanding the complex relationship between these PTMs is still under investigation and can provide new, promising therapeutic targets and treatment approaches. This review, using a systematic review of the literature, presents the current knowledge on PTMs of the mPTP and their role in health and cardiac disease.
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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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Shevtsova EF, Maltsev AV, Vinogradova DV, Shevtsov PN, Bachurin SO. Mitochondria as a promising target for developing novel agents for treating Alzheimer's disease. Med Res Rev 2020; 41:803-827. [PMID: 32687230 DOI: 10.1002/med.21715] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022]
Abstract
The mitochondria-targeting drugs can be conventionally divided into the following groups: those compensating for the energy deficit involved in neurodegeneration, including stimulants of mitochondrial bioenergetics and activators of mitochondrial biogenesis; and neuroprotectors, that are compounds increasing the resistance of mitochondria to opening of mitochondrial permeability transition (MPT) pores. Although compensating for the energy deficit and inhibition of MPT are obvious targets for drugs used in the very early stages of Alzheimer-like pathology, but their use as the monotherapy for patients with severe symptoms is unlikely to be sufficiently effective. It would be optimal to combine targets that would provide the cognitive-stimulating, the neuroprotective effects and the ability to affect specific disease-forming mechanisms. In the design of such drugs, assessment of their potential mitochondrial-targeted effects is of particular importance. The possibility of targeted drug design for simultaneous action on mitochondrial and neurotransmitter's receptors targets is, in particularly, based on the known interplay of various cellular pathways and the presence of common structural components. Of particular interest is directed search for multitarget drugs that would act simultaneously on mitochondrial calcium-dependent functions, the targets (receptors, enzymes, etc.) facilitating neurotransmission, and the molecular targets related to the action of so-called disease-modifying factors, in particular, the formation and overcoming of the toxicity of β-amyloid or hyperphosphorylated tau protein. The examples of such approaches realized on the level of preclinical and clinical trials are presented below.
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Affiliation(s)
- Elena F Shevtsova
- Department of Medicinal and Biological Chemistry, Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Moscow Region, Russia
| | - Andrey V Maltsev
- Department of Medicinal and Biological Chemistry, Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Moscow Region, Russia
| | - Darya V Vinogradova
- Department of Medicinal and Biological Chemistry, Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Moscow Region, Russia
| | - Pavel N Shevtsov
- Department of Medicinal and Biological Chemistry, Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Moscow Region, Russia
| | - Sergey O Bachurin
- Department of Medicinal and Biological Chemistry, Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Moscow Region, Russia
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Lee Y, Park Y, Nam H, Lee JW, Yu SW. Translocator protein (TSPO): the new story of the old protein in neuroinflammation. BMB Rep 2020. [PMID: 31818362 PMCID: PMC6999824 DOI: 10.5483/bmbrep.2020.53.1.273] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Translocator protein (TSPO), also known as peripheral benzodiazepine receptor, is a transmembrane protein located on the outer mitochondria membrane (OMM) and mainly expressed in glial cells in the brain. Because of the close correlation of its expression level with neuropathology and therapeutic efficacies of several TSPO binding ligands under many neurological conditions, TSPO has been regarded as both biomarker and therapeutic target, and the biological functions of TSPO have been a major research focus. However, recent genetic studies with animal and cellular models revealed unexpected results contrary to the anticipated biological importance of TSPO and cast doubt on the action modes of the TSPO-binding drugs. In this review, we summarize recent controversial findings on the discrepancy between pharmacological and genetic studies of TSPO and suggest some future direction to understand this old and mysterious protein.
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Affiliation(s)
- Younghwan Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Youngjin Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Hyeri Nam
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Ji-Won Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
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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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14
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Weber JJ, Clemensson LE, Schiöth HB, Nguyen HP. Olesoxime in neurodegenerative diseases: Scrutinising a promising drug candidate. Biochem Pharmacol 2019; 168:305-318. [PMID: 31283931 DOI: 10.1016/j.bcp.2019.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/03/2019] [Indexed: 12/14/2022]
Abstract
Over the last years, the experimental compound olesoxime, a mitochondria-targeting cholesterol derivative, has emerged as a promising drug candidate for neurodegenerative diseases. Numerous preclinical studies have successfully proved olesoxime's neuroprotective properties in cell and animal models of clinical conditions such as amyotrophic lateral sclerosis, Huntington disease, Parkinson disease, peripheral neuropathy and spinal muscular atrophy. The beneficial effects were attributed to olesoxime's potential impact on oxidative stress, mitochondrial permeability transition or cholesterol homoeostasis. Although no significant benefits have been demonstrated in patients of amyotrophic lateral sclerosis, and only the first 12 months of a phase II/III clinical trial showed an improvement in motor symptoms of spinal muscular atrophy, this orphan drug may still offer undiscovered potential in the treatment of neurological diseases. In our earlier preclinical studies, we demonstrated that administration of olesoxime in mouse and rat models of Huntington disease improved psychiatric and molecular phenotypes. Aside from stabilising mitochondrial function, the drug reduced the overactivation of calpains, a class of calcium-dependent proteases entangled in neurodegenerative conditions. This observation may be credited to olesoxime's action on calcium dyshomeostasis, a further hallmark in neurodegeneration, and linked to its targets TSPO and VDAC, two proteins of the outer mitochondrial membrane associated with mitochondrial calcium handling. Further research into the mode of action of olesoxime under pathological conditions, including its effect on neuronal calcium homeostasis, may strengthen the untapped potential of olesoxime or other similar compounds as a therapeutic for neurodegenerative diseases.
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Affiliation(s)
- Jonasz Jeremiasz Weber
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.
| | | | - Helgi Birgir Schiöth
- Department of Neuroscience, Uppsala University, Uppsala, Sweden; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia.
| | - Huu Phuc Nguyen
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany; Department of Human Genetics, Ruhr-University Bochum, Bochum, Germany.
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15
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Papadopoulos V, Fan J, Zirkin B. Translocator protein (18 kDa): an update on its function in steroidogenesis. J Neuroendocrinol 2018; 30:10.1111/jne.12500. [PMID: 28667781 PMCID: PMC5748373 DOI: 10.1111/jne.12500] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 12/15/2022]
Abstract
Translocator protein (18 kDa) (TSPO) is a ubiquitous mitochondrial protein. Studies of its responses to drug and endogenous ligands have shown TSPO to be involved either directly or indirectly in numerous biological functions, including mitochondrial cholesterol transport and steroid hormone biosynthesis, porphyrin transport and heme synthesis, apoptosis, cell proliferation, and anion transport. Localised to the outer mitochondrial membrane of steroidogenic cells, TSPO has been shown to associate with cytosolic and mitochondrial proteins as part of a large multiprotein complex involved in mitochondrial cholesterol transport, the rate-limiting step in steroidogenesis. There is general agreement as to the structure and pharmacology of TSPO. Stimulation of TSPO has been shown to have therapeutic use as anxiolytics by inducing allopregnanolone production in the brain, and also potentially for re-establishing androgen levels in hypogonadal ageing animals. Until recently, there has been general agreement regarding the role of TSPO in steroidogenesis. However, recent studies involving genetic depletion of TSPO in mice have created controversy about the role of this protein in steroid and heme synthesis. We review the data on the structure and function of TSPO, as well as the recent results obtained using various genetic animal models. Taken together, these studies suggest that TSPO is a unique mitochondrial pharmacological target for diseases that involve increased mitochondrial activity, including steroidogenesis. Although there is no known mammalian species that lacks TSPO, it is likely that, because of the importance of this ancient protein in evolution and mitochondrial function, redundant mechanisms may exist to replace it under circumstances when it is removed.
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Affiliation(s)
- Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
- Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, H4A 3J1, Canada
| | - Jinjiang Fan
- Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, H4A 3J1, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
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16
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Shoshan-Barmatz V, Maldonado EN, Krelin Y. VDAC1 at the crossroads of cell metabolism, apoptosis and cell stress. Cell Stress 2017; 1:11-36. [PMID: 30542671 PMCID: PMC6287957 DOI: 10.15698/cst2017.10.104] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This review presents current knowledge related to VDAC1 as a multi-functional mitochondrial protein acting on both sides of the coin, regulating cell life and death, and highlighting these functions in relation to disease. It is now recognized that VDAC1 plays a crucial role in regulating the metabolic and energetic functions of mitochondria. The location of VDAC1 at the outer mitochondrial membrane (OMM) allows the control of metabolic cross-talk between mitochondria and the rest of the cell and also enables interaction of VDAC1 with proteins involved in metabolic and survival pathways. Along with regulating cellular energy production and metabolism, VDAC1 is also involved in the process of mitochondria-mediated apoptosis by mediating the release of apoptotic proteins and interacting with anti-apoptotic proteins. VDAC1 functions in the release of apoptotic proteins located in the mitochondrial intermembrane space via oligomerization to form a large channel that allows passage of cytochrome c and AIF and their release to the cytosol, subsequently resulting in apoptotic cell death. VDAC1 also regulates apoptosis via interactions with apoptosis regulatory proteins, such as hexokinase, Bcl2 and Bcl-xL, some of which are also highly expressed in many cancers. This review also provides insight into VDAC1 function in Ca2+ homeostasis, oxidative stress, and presents VDAC1 as a hub protein interacting with over 100 proteins. Such interactions enable VDAC1 to mediate and regulate the integration of mitochondrial functions with cellular activities. VDAC1 can thus be considered as standing at the crossroads between mitochondrial metabolite transport and apoptosis and hence represents an emerging cancer drug target.
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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
| | - Eduardo N Maldonado
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC. USA
| | - 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
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17
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Shoshan-Barmatz V, Krelin Y, Shteinfer-Kuzmine A. VDAC1 functions in Ca 2+ homeostasis and cell life and death in health and disease. Cell Calcium 2017; 69:81-100. [PMID: 28712506 DOI: 10.1016/j.ceca.2017.06.007] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/21/2017] [Accepted: 06/21/2017] [Indexed: 01/15/2023]
Abstract
In the outer mitochondrial membrane (OMM), the voltage-dependent anion channel 1 (VDAC1) serves as a mitochondrial gatekeeper, controlling the metabolic and energy cross-talk between mitochondria and the rest of the cell. VDAC1 also functions in cellular Ca2+ homeostasis by transporting Ca2+ in and out of mitochondria. VDAC1 has also been recognized as a key protein in mitochondria-mediated apoptosis, contributing to the release of apoptotic proteins located in the inter-membranal space (IMS) and regulating apoptosis via association with pro- and anti-apoptotic members of the Bcl-2 family of proteins and hexokinase. VDAC1 is highly Ca2+-permeable, transporting Ca2+ to the IMS and thus modulating Ca2+ access to Ca2+ transporters in the inner mitochondrial membrane. Intra-mitochondrial Ca2+ controls energy metabolism via modulating critical enzymes in the tricarboxylic acid cycle and in fatty acid oxidation. Ca2+ also determines cell sensitivity to apoptotic stimuli and promotes the release of pro-apoptotic proteins. However, the precise mechanism by which intracellular Ca2+ mediates apoptosis is not known. Here, the roles of VDAC1 in mitochondrial Ca2+ homeostasis are presented while emphasizing a new proposed mechanism for the mode of action of pro-apoptotic drugs. This view, proposing that Ca2+-dependent enhancement of VDAC1 expression levels is a major mechanism by which apoptotic stimuli induce apoptosis, position VDAC1 oligomerization at a molecular focal point in apoptosis regulation. The interactions of VDAC1 with many proteins involved in Ca2+ homeostasis or regulated by Ca2+, as well as VDAC-mediated control of cell life and death and the association of VDAC with disease, are also presented.
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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.
| | - 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
| | - Anna Shteinfer-Kuzmine
- 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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18
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Classical and Novel TSPO Ligands for the Mitochondrial TSPO Can Modulate Nuclear Gene Expression: Implications for Mitochondrial Retrograde Signaling. Int J Mol Sci 2017; 18:ijms18040786. [PMID: 28387723 PMCID: PMC5412370 DOI: 10.3390/ijms18040786] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 03/24/2017] [Accepted: 03/27/2017] [Indexed: 12/22/2022] Open
Abstract
It is known that knockdown of the mitochondrial 18 kDa translocator protein (TSPO) as well as TSPO ligands modulate various functions, including functions related to cancer. To study the ability of TSPO to regulate gene expression regarding such functions, we applied microarray analysis of gene expression to U118MG glioblastoma cells. Within 15 min, the classical TSPO ligand PK 11195 induced changes in expression of immediate early genes and transcription factors. These changes also included gene products that are part of the canonical pathway serving to modulate general gene expression. These changes are in accord with real-time, reverse transcriptase (RT) PCR. At the time points of 15, 30, 45, and 60 min, as well as 3 and 24 h of PK 11195 exposure, the functions associated with the changes in gene expression in these glioblastoma cells covered well known TSPO functions. These functions included cell viability, proliferation, differentiation, adhesion, migration, tumorigenesis, and angiogenesis. This was corroborated microscopically for cell migration, cell accumulation, adhesion, and neuronal differentiation. Changes in gene expression at 24 h of PK 11195 exposure were related to downregulation of tumorigenesis and upregulation of programmed cell death. In the vehicle treated as well as PK 11195 exposed cell cultures, our triple labeling showed intense TSPO labeling in the mitochondria but no TSPO signal in the cell nuclei. Thus, mitochondrial TSPO appears to be part of the mitochondria-to-nucleus signaling pathway for modulation of nuclear gene expression. The novel TSPO ligand 2-Cl-MGV-1 appeared to be very specific regarding modulation of gene expression of immediate early genes and transcription factors.
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Effect of the CRAC Peptide, VLNYYVW, on mPTP Opening in Rat Brain and Liver Mitochondria. Int J Mol Sci 2016; 17:ijms17122096. [PMID: 27983605 PMCID: PMC5187896 DOI: 10.3390/ijms17122096] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 12/01/2016] [Accepted: 12/07/2016] [Indexed: 01/08/2023] Open
Abstract
The translocator protein (TSPO; 18 kDa) is a high-affinity cholesterol-binding protein located in the outer membrane of mitochondria. A domain in the C-terminus of TSPO was characterized as the cholesterol recognition/interaction amino acid consensus (CRAC). The ability of the CRAC domain to bind to cholesterol led us to hypothesize that this peptide may participate in the regulation of mitochondrial membrane permeability. Herein, we report the effect of the synthetic CRAC peptide, VLNYYVW, on mitochondrial permeability transition pore (mPTP) opening. It was found that the CRAC peptide alone prevents the mPTP from opening, as well as the release of apoptotic factors (cytochrome c, AIF, and EndoG) in rat brain mitochondria (RBM). Co-incubation of CRAC, together with the TSPO drug ligand, PK 11195, resulted in the acceleration of mPTP opening and in the increase of apoptotic factor release. VLNYYVW did not induce swelling in rat liver mitochondria (RLM). 3,17,19-androsten-5-triol (19-Atriol; an inhibitor of the cholesterol-binding activity of the CRAC peptide) alone and in combination with the peptide was able to stimulate RLM swelling, which was Ca2+- and CsA-sensitive. Additionally, a combination of 19-Atriol with 100 nM PK 11195 or with 100 µM PK 11195 displayed the opposite effect: namely, the addition of 19-Atriol with 100 µM PK 11195 in a suspension of RLM suppressed the Ca2+-induced swelling of RLM by 40%, while the presence of 100 nM PK 11195 with 19-Atriol enhanced the swelling of RLM by 60%. Taken together, these data suggest the participation of the TSPO’s CRAC domain in the regulation of permeability transition.
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