1
|
Campellone KG, Lebek NM, King VL. Branching out in different directions: Emerging cellular functions for the Arp2/3 complex and WASP-family actin nucleation factors. Eur J Cell Biol 2023; 102:151301. [PMID: 36907023 DOI: 10.1016/j.ejcb.2023.151301] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 02/07/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
The actin cytoskeleton impacts practically every function of a eukaryotic cell. Historically, the best-characterized cytoskeletal activities are in cell morphogenesis, motility, and division. The structural and dynamic properties of the actin cytoskeleton are also crucial for establishing, maintaining, and changing the organization of membrane-bound organelles and other intracellular structures. Such activities are important in nearly all animal cells and tissues, although distinct anatomical regions and physiological systems rely on different regulatory factors. Recent work indicates that the Arp2/3 complex, a broadly expressed actin nucleator, drives actin assembly during several intracellular stress response pathways. These newly described Arp2/3-mediated cytoskeletal rearrangements are coordinated by members of the Wiskott-Aldrich Syndrome Protein (WASP) family of actin nucleation-promoting factors. Thus, the Arp2/3 complex and WASP-family proteins are emerging as crucial players in cytoplasmic and nuclear activities including autophagy, apoptosis, chromatin dynamics, and DNA repair. Characterizations of the functions of the actin assembly machinery in such stress response mechanisms are advancing our understanding of both normal and pathogenic processes, and hold great promise for providing insights into organismal development and interventions for disease.
Collapse
Affiliation(s)
- Kenneth G Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA.
| | - Nadine M Lebek
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
| | - Virginia L King
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
| |
Collapse
|
2
|
Anjum S, Chaudhary R, Khan AK, Hashim M, Anjum I, Hano C, Abbasi BH. Light-emitting diode (LED)-directed green synthesis of silver nanoparticles and evaluation of their multifaceted clinical and biological activities. RSC Adv 2022; 12:22266-22284. [PMID: 36043104 PMCID: PMC9364226 DOI: 10.1039/d2ra03503k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/25/2022] [Indexed: 11/21/2022] Open
Abstract
The trend of using plant extracts for the synthesis of nanoparticles has increased in recent years due to environmental safety, low cost, simplicity and sustainability of the green route. Moreover, the morphology of NPs can be fine-tuned by applying abiotic factors such as LEDs, which enhance the bio-reduction of the precursor salt and excite phytochemicals during their green synthesis. Considering this, in present study, the green synthesis of AgNPs was carried out using Dalbergia sissoo leaf extract under the illumination of red, green, blue, yellow and white LEDs. The phytochemical profile of the leaf extract in terms of total phenolic and flavonoid content was responsible for the effective synthesis of AgNPs, where alcohols and phenols were mainly involved in the capping and bio-reduction of the NPs. Moreover, the XRD data showed the face center cubic crystalline nature of the AgNPs with the interesting finding that the LEDs helped to reduce the size of the AgNPs significantly. Among the samples, Y-DS-AgNPs (34.63 nm) were the smallest in size, with the control having a size of 87.35 nm. The LEDs not only reduced the size of the AgNPs but also resulted in the synthesis of non-agglomerated AgNPs with different shapes including spherical, triangular, and hexagonal compared to the mixed-shape control AgNPs, as shown by the SEM analysis. These LED-directed AgNPs showed extraordinary therapeutic potential especially B-DS-AgNPs, which exhibited the highest anti-oxidant, anti-glycation and anti-bacterial activities. Alternatively, Y-DS-AgNPs were the most cytotoxic towards HepG2 cells, inducing intracellular ROS/RNS production, accompanied by a disruption in the mitochondrial membrane potential, caspase-3 gene activation and induction of caspase-3/7 activity. Lastly, AgNPs showed mild toxicity towards brine shrimp and moderately hemolyzed hRBCs, showing their biosafe nature. Here, we conclude that external factors such as LEDs are effective in controlling the morphology of AgNPs, which further enhanced their therapeutic efficacy.
Collapse
Affiliation(s)
- Sumaira Anjum
- Department of Biotechnology, Kinnaird College for Women 92-Jail Road Lahore-54000 Pakistan +92-3006957038
| | - Rimsha Chaudhary
- Department of Biotechnology, Kinnaird College for Women 92-Jail Road Lahore-54000 Pakistan +92-3006957038
| | - Amna Komal Khan
- Department of Biotechnology, Kinnaird College for Women 92-Jail Road Lahore-54000 Pakistan +92-3006957038
| | - Mariam Hashim
- Department of Biotechnology, Kinnaird College for Women 92-Jail Road Lahore-54000 Pakistan +92-3006957038
| | - Iram Anjum
- Department of Biotechnology, Kinnaird College for Women 92-Jail Road Lahore-54000 Pakistan +92-3006957038
| | - Christophe Hano
- Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRAE USC1328, University of Orleans 45067 Orléans CEDEX 2 France
| | - Bilal Haider Abbasi
- Department of Biotechnology, Quaid-i-Azam University Islamabad-45320 Pakistan
| |
Collapse
|
3
|
Biological Effects and Mechanisms of Caspases in Early Brain Injury after Subarachnoid Hemorrhage. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:3345637. [PMID: 35847583 PMCID: PMC9277153 DOI: 10.1155/2022/3345637] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 06/22/2022] [Indexed: 12/12/2022]
Abstract
Caspases are an evolutionarily conserved family of proteases responsible for mediating and initiating cell death signals. In the past, the dysregulated activation of caspases was reported to play diverse but equally essential roles in neurodegenerative diseases, such as brain injury and neuroinflammatory diseases. A subarachnoid hemorrhage (SAH) is a traumatic event that is either immediately lethal or induces a high risk of stroke and neurological deficits. Currently, the prognosis of SAH after treatment is not ideal. Early brain injury (EBI) is considered one of the main factors contributing to the poor prognosis of SAH. The mechanisms of EBI are complex and associated with oxidative stress, neuroinflammation, blood-brain barrier disruption, and cell death. Based on mounting evidence, caspases are involved in neuronal apoptosis or death, endothelial cell apoptosis, and increased inflammatory cytokine-induced by apoptosis, pyroptosis, and necroptosis in the initial stages after SAH. Caspases can simultaneously mediate multiple death modes and regulate each other. Caspase inhibitors (including XIAP, VX-765, and Z-VAD-FMK) play an essential role in ameliorating EBI after SAH. In this review, we explore the related pathways mediated by caspases and their reciprocal regulation patterns after SAH. Furthermore, we focus on the extensive crosstalk of caspases as a potential area of research on therapeutic strategies for treating EBI after SAH.
Collapse
|
4
|
Hiu JJ, Yap MKK. The myth of cobra venom cytotoxin: More than just direct cytolytic actions. Toxicon X 2022; 14:100123. [PMID: 35434602 PMCID: PMC9011113 DOI: 10.1016/j.toxcx.2022.100123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/03/2022] [Accepted: 03/31/2022] [Indexed: 12/26/2022] Open
Abstract
Cobra venom cytotoxin (CTX) is a non-enzymatic three-finger toxin that constitutes 40-60% of cobra venom. Thus, it plays an important role in the pathophysiology of cobra envenomation, especially in local dermonecrosis. The three-finger hydrophobic loops of CTX determine the cytotoxicity. Nevertheless, the actual mechanisms of cytotoxicity are not fully elucidated as they involve not only cytolytic actions but also intracellular signalling-mediated cell death pathways. Furthermore, the possible transition cell death pattern remains to be explored. The actual molecular mechanisms require further studies to unveil the relationship between different CTXs from different cobra species and cell types which may result in differential cell death patterns. Here, we discuss the biophysical interaction of CTX with the cell membrane involving four binding modes: electrostatic interaction, hydrophobic partitioning, isotropic phase, and oligomerisation. Oligomerisation of CTX causes pore formation in the membrane lipid bilayer. Additionally, the CTX-induced apoptotic pathway can be executed via death receptor-mediated extrinsic pathways and mitochondrial-mediated intrinsic pathways. We also discuss lysosomal-mediated necrosis and the occurrence of necroptosis following CTX action. Collectively, we provided an insight into concentration-dependent transition of cell death pattern which involves different mechanistic actions. This contributes a new direction for further investigation of cytotoxic pathways activated by the CTXs for future development of biotherapeutics targeting pathological effects caused by CTX.
Collapse
Affiliation(s)
- Jia Jin Hiu
- School of Science, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Michelle Khai Khun Yap
- School of Science, Monash University Malaysia, Bandar Sunway, Malaysia.,Tropical Medicine and Biology Multidisciplinary Platform, Monash University Malaysia, Bandar Sunway, Malaysia
| |
Collapse
|
5
|
Heib M, Weiß J, Saggau C, Hoyer J, Fuchslocher Chico J, Voigt S, Adam D. Ars moriendi: Proteases as sculptors of cellular suicide. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119191. [PMID: 34973300 DOI: 10.1016/j.bbamcr.2021.119191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
The Ars moriendi, which translates to "The Art of Dying," encompasses two Latin texts that gave advice on how to die well and without fear according to the Christian precepts of the late Middle Ages. Given that ten to hundred billion cells die in our bodies every day, it is obvious that the concept of a well and orderly ("regulated") death is also paramount at the cellular level. In apoptosis, as the most well-studied form of regulated cell death, proteases of the caspase family are the central mediators. However, caspases are not the only proteases that act as sculptors of cellular suicide, and therefore, we here provide an overview of the impact of proteases in apoptosis and other forms of regulated cell death.
Collapse
Affiliation(s)
- Michelle Heib
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Jonas Weiß
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Carina Saggau
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Justus Hoyer
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | | | - Susann Voigt
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany
| | - Dieter Adam
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105 Kiel, Germany.
| |
Collapse
|
6
|
Feng X, Yan Z, Zhou F, Lou J, Lyu X, Ren X, Zeng Z, Liu C, Zhang S, Zhu D, Huang H, Yang J, Zhao Y. Discovery of a selective and covalent small-molecule inhibitor of BFL-1 protein that induces robust apoptosis in cancer cells. Eur J Med Chem 2022; 236:114327. [DOI: 10.1016/j.ejmech.2022.114327] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/18/2022] [Accepted: 03/25/2022] [Indexed: 11/30/2022]
|
7
|
Anjum S, Khan AK, Qamar A, Fatima N, Drouet S, Renouard S, Blondeau JP, Abbasi BH, Hano C. Light Tailoring: Impact of UV-C Irradiation on Biosynthesis, Physiognomies, and Clinical Activities of Morus macroura-Mediated Monometallic (Ag and ZnO) and Bimetallic (Ag-ZnO) Nanoparticles. Int J Mol Sci 2021; 22:11294. [PMID: 34681952 PMCID: PMC8540622 DOI: 10.3390/ijms222011294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/19/2021] [Accepted: 09/20/2021] [Indexed: 12/30/2022] Open
Abstract
A nano-revolution based on the green synthesis of nanomaterials could affect all areas of human life, and nanotechnology represents a propitious platform for various biomedical applications. During the synthesis of nanoparticles, various factors can control their physiognomies and clinical activities. Light is one of the major physical factors that can play an important role in tuning/refining the properties of nanoparticles. In this study, biocompatible monometallic (AgNPs and ZnONPs) and bimetallic Ag-ZnONPs (0.1/0.1 and 0.1/0.5) were synthesized under UV-C light irradiation from the leaf extract of Morus macroura, which possesses enriched TPC (4.238 ± 0.26 mg GAE/g DW) and TFC (1.073 ± 0.18 mg QE/g DW), as well as strong FRSA (82.39%). These green synthesized NPs were evaluated for their anti-diabetic, anti-glycation, and biocompatibility activities. Furthermore, their anti-cancerous activity against HepG2 cell lines was assessed in terms of cell viability, production of reactive oxygen/nitrogen species, mitochondrial membrane potential, and apoptotic caspase-3/7 expression and activity. Synthesized NPs were characterized by techniques including ultraviolet-visible spectroscopy, SEM, EDX, FTIR, and XRD. UV-C mediated monometallic and bimetallic NPs showed well-defined characteristic shapes with a more disperse particle distribution, definite crystalline structures, and reduced sizes as compared to their respective controls. In the case of clinical activities, the highest anti-diabetic activity (67.77 ± 3.29% against α-amylase and 35.83 ± 2.40% against α-glucosidase) and anti-glycation activity (37.68 ± 3.34% against pentosidine-like AGEs and 67.87 ± 2.99% against vesperlysine-like AGEs) was shown by UV-C mediated AgNPs. The highest biocompatibility (IC50 = 14.23 ± 1.68 µg/mL against brine shrimp and 2.48 ± 0.32% hemolysis of human red blood cells) was shown by UV-C mediated ZnONPs. In the case of anti-cancerous activities, the lowest viability (23.45 ± 1.40%) with enhanced ROS/NOS production led to a significant disruption of mitochondrial membrane potential and greater caspase-3/7 gene expression and activity by UV-C mediated bimetallic Ag-ZnONPs (0.1/0.5). The present work highlights the positive effects of UV-C light on physico-chemical physiognomies as well as the clinical activities of NPs.
Collapse
Affiliation(s)
- Sumaira Anjum
- Department of Biotechnology, Kinnaird College for Women, 93-Jail Road, Lahore 54000, Pakistan; (A.K.K.); (A.Q.); (N.F.)
| | - Amna Komal Khan
- Department of Biotechnology, Kinnaird College for Women, 93-Jail Road, Lahore 54000, Pakistan; (A.K.K.); (A.Q.); (N.F.)
| | - Anza Qamar
- Department of Biotechnology, Kinnaird College for Women, 93-Jail Road, Lahore 54000, Pakistan; (A.K.K.); (A.Q.); (N.F.)
| | - Noor Fatima
- Department of Biotechnology, Kinnaird College for Women, 93-Jail Road, Lahore 54000, Pakistan; (A.K.K.); (A.Q.); (N.F.)
| | - Samantha Drouet
- Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRAE USC1328, University of Orléans, CEDEX 2, 45067 Orléans, France; (S.D.); (C.H.)
| | - Sullivan Renouard
- Institut de Chimie et de Biologie des Membranes et des Nano-objets, CNRS UMR 5248, Bordeaux University, 33600 Pessac, France;
| | - Jean Philippe Blondeau
- Conditions Extrêmes et Matériaux: Haute Température et Irradiation (CEMHTI) CNRS UPR3079, 1D Avenue de la Recherche Scientifique, 45071 Orléans, France;
| | - Bilal Haider Abbasi
- Department of Biotechnology, Quaid-i-Azam University, Islamabad 15320, Pakistan;
| | - Christophe Hano
- Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRAE USC1328, University of Orléans, CEDEX 2, 45067 Orléans, France; (S.D.); (C.H.)
| |
Collapse
|
8
|
Sahebazzamani F, Hosseinkhani S, Eriksson LA, Fearnhead HO. Apoptosome Formation through Disruption of the K192-D616 Salt Bridge in the Apaf-1 Closed Form. ACS OMEGA 2021; 6:22551-22558. [PMID: 34514227 PMCID: PMC8427654 DOI: 10.1021/acsomega.1c02274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
The molecular mechanism of apoptosome activation through conformational changes of Apaf-1 auto-inhibited form remains largely enigmatic. The crystal structure of Apaf-1 suggests that some ionic bonds, including the bond between K192 and D616, are critical for the preservation of the inactive "closed" form of Apaf-1. Here, a split luciferase complementation assay was used to monitor the effect of disrupting this ionic bond on apoptosome activation and caspase-3 activity in cells. The K192E mutation, predicted to disrupt the ionic interaction with D616, increased apoptosome formation and caspase activity, suggesting that this mutation favors the "open"/active form of Apaf-1. However, mutation of D616 to alanine or lysine had different effects. While both mutants favored apoptosome formation such as K192E, D616K cannot activate caspases and D616A activates caspases poorly, and not as well as wild-type Apaf-1. Thus, our data show that the ionic bond between K192 and D616 is critical for maintaining the closed form of Apaf-1 and that disrupting the interaction enhances apoptosome formation. However, our data also reveal that after apoptosome formation, D616 and K192 play a previously unsuspected role in caspase activation. The molecular explanation for this observation is yet to be elucidated.
Collapse
Affiliation(s)
- Fatemeh Sahebazzamani
- Department
of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saman Hosseinkhani
- Department
of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Leif A. Eriksson
- Department
of Chemistry and Molecular Biology, University
of Gothenburg, Göteborg 405 30, Sweden
| | - Howard O. Fearnhead
- Pharmacology
and Therapeutics, School of Medicine, NUI
Galway, Galway, Ireland
| |
Collapse
|
9
|
Duxbury Z, Wu CH, Ding P. A Comparative Overview of the Intracellular Guardians of Plants and Animals: NLRs in Innate Immunity and Beyond. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:155-184. [PMID: 33689400 DOI: 10.1146/annurev-arplant-080620-104948] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nucleotide-binding domain leucine-rich repeat receptors (NLRs) play important roles in the innate immune systems of both plants and animals. Recent breakthroughs in NLR biochemistry and biophysics have revolutionized our understanding of how NLR proteins function in plant immunity. In this review, we summarize the latest findings in plant NLR biology and draw direct comparisons to NLRs of animals. We discuss different mechanisms by which NLRs recognize their ligands in plants and animals. The discovery of plant NLR resistosomes that assemble in a comparable way to animal inflammasomes reinforces the striking similarities between the formation of plant and animal NLR complexes. Furthermore, we discuss the mechanisms by which plant NLRs mediate immune responses and draw comparisons to similar mechanisms identified in animals. Finally, we summarize the current knowledge of the complex genetic architecture formed by NLRs in plants and animals and the roles of NLRs beyond pathogen detection.
Collapse
Affiliation(s)
- Zane Duxbury
- Jealott's Hill International Research Centre, Syngenta, Bracknell RG42 6EY, United Kingdom;
| | - Chih-Hang Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan;
| | - Pingtao Ding
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
- Current affiliation: Institute of Biology Leiden, Leiden University, Leiden 2333 BE, The Netherlands;
| |
Collapse
|
10
|
Transient transfection of WT-αS and A53T-αS brought about a mild apoptosis due to degradation of released cytochrome c through PARC. Int J Biol Macromol 2020; 166:374-384. [PMID: 33122072 DOI: 10.1016/j.ijbiomac.2020.10.196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/07/2020] [Accepted: 10/24/2020] [Indexed: 11/22/2022]
Abstract
α-Synuclein (αS) aggregates plays a pivotal role in the pathogenesis of synucleinopathies including Parkinson's Disease. The toxicity of αS aggregates has been broadly studied and variant defects have been reported through which these aggregates lead in cell death. Although cell death through apoptosis pathway has been proposed in many studies, the molecular details underlying in this pathway have not been uncovered. To shed a light on the relationships between αS aggregates and apoptotic cell death, changes in levels and behavior of molecular indicators of the intrinsic apoptotic pathway was investigated in HEK-293T cells overexpressing wild-type α-synuclein and A53T-α-synuclein. Overexpression of both WT-αS and A53T-αS resulted in the increase of caspase-9 activity, and rise in Cytochrome c (Cyt c) and PARC content, concurrently. We assume that rising in PARC level may result in Cyt c degradation, and consequently suppressing/attenuating intrinsic apoptosis pathway. Besides, increasing of Casp-9 activity can be related to αS aggregates and subsequent degradation of Cyt c. To understand the mechanisms behind this using theoretical model, molecular dynamic simulation was also applied to investigate the possible interaction of Casp-9 with α-synuclein aggregates. The results showed that the interaction between Casp-9 with αS aggregates could activate Casp-9 by changing the conformation of some crucial residues.
Collapse
|
11
|
Kwak AW, Lee MH, Yoon G, Cho SS, Choi JS, Chae JI, Shim JH. Deoxypodophyllotoxin, a Lignan from Anthriscus sylvestris, Induces Apoptosis and Cell Cycle Arrest by Inhibiting the EGFR Signaling Pathways in Esophageal Squamous Cell Carcinoma Cells. Int J Mol Sci 2020; 21:ijms21186854. [PMID: 32961992 PMCID: PMC7555783 DOI: 10.3390/ijms21186854] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/16/2020] [Accepted: 09/16/2020] [Indexed: 12/16/2022] Open
Abstract
Deoxypodophyllotoxin (DPT) derived from Anthriscus sylvestris (L.) Hoffm has attracted considerable interest in recent years because of its anti-inflammatory, antitumor, and antiviral activity. However, the mechanisms underlying DPT mediated antitumor activity have yet to be fully elucidated in esophageal squamous cell carcinoma (ESCC). We show here that DPT inhibited the kinase activity of epidermal growth factor receptor (EGFR) directly, as well as phosphorylation of its downstream signaling kinases, AKT, GSK-3β, and ERK. We confirmed a direct interaction between DPT and EGFR by pull-down assay using DPT-beads. DPT treatment suppressed ESCC cell viability and colony formation in a time- and dose-dependent manner, as shown by MTT analysis and soft agar assay. DPT also down-regulated cyclin B1 and cdc2 expression to induce G2/M phase arrest of the cell cycle and upregulated p21 and p27 expression. DPT treatment of ESCC cells triggered the release of cytochrome c via loss of mitochondrial membrane potential, thereby inducing apoptosis by upregulation of related proteins. In addition, treatment of KYSE 30 and KYSE 450 cells with DPT increased endoplasmic reticulum stress, reactive oxygen species generation, and multi-caspase activation. Consequently, our results suggest that DPT has the potential to become a new anticancer therapeutic by inhibiting EGFR mediated AKT/ERK signaling pathway in ESCC.
Collapse
Affiliation(s)
- Ah-Won Kwak
- Department of Pharmacy, College of Pharmacy, Mokpo National University, Jeonnam 58554, Korea; (A.-W.K.); (G.Y.); (S.-S.C.)
| | - Mee-Hyun Lee
- College of Korean Medicine, Dongshin University, Naju, Jeonnam 58245, Korea;
| | - Goo Yoon
- Department of Pharmacy, College of Pharmacy, Mokpo National University, Jeonnam 58554, Korea; (A.-W.K.); (G.Y.); (S.-S.C.)
| | - Seung-Sik Cho
- Department of Pharmacy, College of Pharmacy, Mokpo National University, Jeonnam 58554, Korea; (A.-W.K.); (G.Y.); (S.-S.C.)
| | - Joon-Seok Choi
- College of Pharmacy, Daegu Catholic University, Hayang-Ro 13-13, Hayang-Eup, Gyeongsan-si, Gyeongbuk 38430, Korea;
| | - Jung-Il Chae
- Department of Dental Pharmacology, School of Dentistry and Institute of Oral Bioscience, BK21 Plus, Jeonbuk National University, Jeonju 54896, Korea
- Correspondence: (J.-I.C.); (J.-H.S.); Tel.: +82-63-270-4024 (J.-I.C.); +82-61-450-2684 (J.-H.S.); Fax: +82-63-270-4037 (J.-I.C.); +82-61-450-2689 (J.-H.S.)
| | - Jung-Hyun Shim
- Department of Pharmacy, College of Pharmacy, Mokpo National University, Jeonnam 58554, Korea; (A.-W.K.); (G.Y.); (S.-S.C.)
- Department of Biomedicine, Health & Life Convergence Sciences, BK21 Four, College of Pharmacy, Mokpo National University, Jeonnam 58554, Korea
- Correspondence: (J.-I.C.); (J.-H.S.); Tel.: +82-63-270-4024 (J.-I.C.); +82-61-450-2684 (J.-H.S.); Fax: +82-63-270-4037 (J.-I.C.); +82-61-450-2689 (J.-H.S.)
| |
Collapse
|
12
|
Cepharanthine induces ROS stress in glioma and neuronal cells via modulation of VDAC permeability. Saudi Pharm J 2020; 28:1364-1373. [PMID: 33250643 PMCID: PMC7679435 DOI: 10.1016/j.jsps.2020.08.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/31/2020] [Indexed: 01/22/2023] Open
Abstract
Cepharanthine (CEP) is a bisbenzylisoquinoline alkaloid. Molecular dynamics studies show that CEP interacts with Voltage-dependent anion channel (VDAC), inducing the voltage-independent channel narrowing. In the new conformation, transport between mitochondria and cytoplasm is altered, which leads to the dose-dependent cytotoxicity. The biological effects of the interaction were investigated on glioblastoma multiforme (SNB-19) and neuronal (PC-12 + NGF) cell lines. The cytotoxic potential of cepharanthine was determined by MTT assay and flow cytometry apoptosis/necrosis studies. T-type calcium channel and VDAC were labelled by the immunocytochemical method. Additionally, fluorescent labelling of reactive oxygen species and mitochondria was performed. Changes in the pore size of VDAC were calculated as well. Molecular dynamics simulations were carried out to examine the interactions of cepharanthine with VDAC. The obtained results prove that cepharanthine enhances the apoptosis in glioma and neuronal cells by the release of reactive oxygen species. Cepharanthine alters the mitochondria-to-cytoplasm transport and thus induces the cytotoxicity with no selectivity.
Collapse
|
13
|
Rahman T, Nagar A, Duffy EB, Okuda K, Silverman N, Harton JA. NLRP3 Sensing of Diverse Inflammatory Stimuli Requires Distinct Structural Features. Front Immunol 2020; 11:1828. [PMID: 32983094 PMCID: PMC7479093 DOI: 10.3389/fimmu.2020.01828] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/08/2020] [Indexed: 12/30/2022] Open
Abstract
The NLRP3 inflammasome is central to host defense and implicated in various inflammatory diseases and conditions. While the favored paradigm of NLRP3 inflammasome activation stipulates a unifying signal intermediate that de-represses NLRP3, this view has not been tested. Further, structures within NLRP3 required for inflammasome activation are poorly defined. Here we demonstrate that while the NLRP3 LRRs are not auto-repressive and are not required for inflammasome activation by all agonists, distinct sequences within the NLRP3 LRRs positively and negatively modulate inflammasome activation by specific ligands. In addition, elements within the HD1/HD2 “hinge” of NLRP3 and the nucleotide-binding domain have contrasting functions depending upon the specific agonists. Further, while NLRP3 1–432 is minimally sufficient for inflammasome activation by all agonists tested, the pyrin, and linker domains (1–134) function cooperatively and are sufficient for inflammasome activation by certain agonists. Conserved cysteines 8 and 108 appear important for inflammasome activation by sterile, but not infectious insults. Our results define common and agonist-specific regions of NLRP3 that likely mediate ligand-specific responses, discount the hypothesis that NLRP3 inflammasome activation has a unified mechanism, and implicate NLRP3 as an integrator of agonist-specific, inflammasome activating signals.
Collapse
Affiliation(s)
- Tabassum Rahman
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Abhinit Nagar
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Ellen B Duffy
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Kendi Okuda
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Neal Silverman
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Jonathan A Harton
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| |
Collapse
|
14
|
Mermigka G, Amprazi M, Mentzelopoulou A, Amartolou A, Sarris PF. Plant and Animal Innate Immunity Complexes: Fighting Different Enemies with Similar Weapons. TRENDS IN PLANT SCIENCE 2020; 25:80-91. [PMID: 31677931 DOI: 10.1016/j.tplants.2019.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/20/2019] [Accepted: 09/30/2019] [Indexed: 05/06/2023]
Abstract
Both animals and plants express intracellular innate immunity receptors known as NLR (NOD-like receptors or nucleotide-binding domain and leucine-rich repeat receptors, respectively). For various mammalian systems, the specific formation of macromolecular structures, such as inflammasomes by activated NLR receptors, has been extensively reported. However, for plant organisms, the formation of such structures was an open scientific question for many years. This year, the first plant 'resistosome' structure was reported, revealing significant structural similarities to mammalian apoptosome and inflammasome structures. In this review, we summarize the key components comprising the mammalian apoptosome/inflammasome structures and the newly discovered plant resistosome, highlighting their commonalities and differences.
Collapse
Affiliation(s)
- Glykeria Mermigka
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, 70013, Crete, Greece
| | - Maria Amprazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, 70013, Crete, Greece; Department of Biology, University of Crete, 714 09 Heraklion, Crete, Greece
| | | | - Argyro Amartolou
- Department of Biology, University of Crete, 714 09 Heraklion, Crete, Greece
| | - Panagiotis F Sarris
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, 70013, Crete, Greece; Department of Biology, University of Crete, 714 09 Heraklion, Crete, Greece; Biosciences, University of Exeter, Geoffrey Pope Building, Exeter EX4 4QD, UK.
| |
Collapse
|
15
|
|
16
|
Dieli-Crimi R, Martínez-Gallo M, Franco-Jarava C, Antolin M, Blasco L, Paramonov I, Semidey ME, Álvarez Fernández A, Molero X, Velásquez J, Martín-Nalda A, Pujol-Borrell R, Colobran R. Th1-skewed profile and excessive production of proinflammatory cytokines in a NFKB1-deficient patient with CVID and severe gastrointestinal manifestations. Clin Immunol 2018; 195:49-58. [PMID: 30063981 DOI: 10.1016/j.clim.2018.07.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/13/2018] [Accepted: 07/27/2018] [Indexed: 02/03/2023]
Abstract
Monoallelic loss-of-function mutations in NFKB1 were recently recognized as the most common monogenic cause of common variable immunodeficiency (CVID). The prototypic clinical phenotype of NFKB1-deficient patients includes common CVID features, such as hypogammaglobulinaemia and sinopulmonary infections, plus other highly variable individual manifestations. Here, we describe a patient with a profound CVID phenotype and severe gastrointestinal manifestations, including chronic and recurrent diarrhoea. Using an NGS customized panel of 323 genes related to primary immunodeficiencies, we identified a novel monoallelic loss-of-function mutation in NFKB1 leading to a truncated protein (c.1149delT/p.Gly384Glu ∗ 48). Interestingly, we also found a rare variant in NOD2 previously associated with Crohn's disease (p.His352Arg). Our patient had hypogammaglobulinaemia with a small number of B cells, most of which were naïve. The most noteworthy findings included marked skewing towards a Th1 phenotype in peripheral blood T cells and excessive production of proinflammatory cytokines (IL-1β, TNFα). The patient's 6-year-old daughter, a carrier of the NFKB1 mutation, is clinically asymptomatic, but has started to show cellular and molecular changes. This case of NFKB1 deficiency appears to be a combination of immunodeficiency and a hyperinflammatory state. The current situation of the patient's daughter provides a glimpse of the preclinical phase of the condition.
Collapse
Affiliation(s)
- Romina Dieli-Crimi
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Catalonia, Spain; Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain
| | - Mónica Martínez-Gallo
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Catalonia, Spain; Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain
| | - Clara Franco-Jarava
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Catalonia, Spain; Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain
| | - Maria Antolin
- Area of Clinical and Molecular Genetics, Hospital Universitari Vall d'Hebron (HUVH), Barcelona, Catalonia, Spain
| | - Laura Blasco
- Area of Clinical and Molecular Genetics, Hospital Universitari Vall d'Hebron (HUVH), Barcelona, Catalonia, Spain
| | - Ida Paramonov
- Area of Clinical and Molecular Genetics, Hospital Universitari Vall d'Hebron (HUVH), Barcelona, Catalonia, Spain
| | - Maria E Semidey
- Pathology Department, Hospital Universitari Vall d'Hebron (HUVH), Barcelona, Catalonia, Spain
| | | | - Xavier Molero
- Exocrine Pancreas Research Unit, Department of Digestive Diseases, Hospital Universitari Vall d'Hebron (HUVH), Autonomous University of Barcelona (UAB), CiberEHD, Barcelona, Catalonia, Spain
| | - Julio Velásquez
- Exocrine Pancreas Research Unit, Department of Digestive Diseases, Hospital Universitari Vall d'Hebron (HUVH), Autonomous University of Barcelona (UAB), CiberEHD, Barcelona, Catalonia, Spain
| | - Andrea Martín-Nalda
- Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain; Pediatric Infectious Diseases and Immunodeficiencies Unit (UPIIP), Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona (UAB), Barcelona, Catalonia, Spain
| | - Ricardo Pujol-Borrell
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Catalonia, Spain; Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain
| | - Roger Colobran
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Catalonia, Spain; Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain; Area of Clinical and Molecular Genetics, Hospital Universitari Vall d'Hebron (HUVH), Barcelona, Catalonia, Spain.
| |
Collapse
|
17
|
Dorstyn L, Akey CW, Kumar S. New insights into apoptosome structure and function. Cell Death Differ 2018; 25:1194-1208. [PMID: 29765111 PMCID: PMC6030056 DOI: 10.1038/s41418-017-0025-z] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 02/08/2023] Open
Abstract
The apoptosome is a platform that activates apical procaspases in response to intrinsic cell death signals. Biochemical and structural studies in the past two decades have extended our understanding of apoptosome composition and structure, while illuminating the requirements for initiator procaspase activation. A number of studies have now provided high-resolution structures for apoptosomes from C. elegans (CED-4), D. melanogaster (Dark), and H. sapiens (Apaf-1), which define critical protein interfaces, including intra and interdomain interactions. This work also reveals interactions of apoptosomes with their respective initiator caspases, CED-3, Dronc and procaspase-9. Structures of the human apoptosome have defined the requirements for cytochrome c binding, which triggers the conversion of inactive Apaf-1 molecules to an extended, assembly competent state. While recent data have provided a detailed understanding of apoptosome formation and procaspase activation, they also highlight important evolutionary differences with functional implications for caspase activation. Comparison of the CARD/CARD disks and apoptosomes formed by CED-4, Dark and Apaf-1. Cartoons of the active states of the CARD-CARD disks, illustrating the two CED-4 CARD tetrameric ring layers (CED4a and CED4b; top row) and the binding of 8 Dronc CARDs and between 3-4 pc-9 CARDs, to the Dark and Apaf-1 CARD disk respectively (middle and lower rows). Ribbon diagrams of the active CED-4, Dark and Apaf-1 apoptosomes are shown (right column).
Collapse
Affiliation(s)
- Loretta Dorstyn
- Center for Cancer Biology, University of South Australia and SA Pathology, Frome Road, Adelaide, SA, 5001, Australia.
| | - Christopher W Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA, 02118, USA
| | - Sharad Kumar
- Center for Cancer Biology, University of South Australia and SA Pathology, Frome Road, Adelaide, SA, 5001, Australia.
| |
Collapse
|
18
|
Constructing Penrose-like tilings with 7-fold symmetry. Struct Chem 2018. [DOI: 10.1007/s11224-018-1083-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
19
|
Stavrou M, Philip B, Traynor-White C, Davis CG, Onuoha S, Cordoba S, Thomas S, Pule M. A Rapamycin-Activated Caspase 9-Based Suicide Gene. Mol Ther 2018; 26:1266-1276. [PMID: 29661681 PMCID: PMC5993966 DOI: 10.1016/j.ymthe.2018.03.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 02/26/2018] [Accepted: 03/03/2018] [Indexed: 01/20/2023] Open
Abstract
Engineered T cell therapies show considerable promise in the treatment of refractory malignancies. Given the ability of engineered T cells to engraft and persist for prolonged periods along with unpredicted toxicities, incorporation of a suicide gene to allow selective depletion after administration is desirable. Rapamycin is a safe and widely available immunosuppressive pharmaceutical that acts by heterodimerization of FKBP12 with the FRB fragment of mTOR. The apical caspase caspase 9 is activated by homodimerization through its CARD domain. We developed a rapamycin-induced caspase 9 suicide gene. First, we showed that caspase 9 could be activated by a two-protein format with replacement of the CARD domain with both FRB and FKBP12. We next identified an optimal compact single-protein rapamycin caspase 9 (rapaCasp9) by fusing both FRB and FKBP12 with the catalytic domain of caspase 9. Functionality of rapaCasp9 when co-expressed with a CD19 CAR was demonstrated in vitro and in vivo.
Collapse
Affiliation(s)
| | - Brian Philip
- Cancer Institute, University College London, London, UK
| | | | | | | | | | - Simon Thomas
- Autolus Ltd., Forest House, White City, London, UK
| | - Martin Pule
- Autolus Ltd., Forest House, White City, London, UK; Cancer Institute, University College London, London, UK.
| |
Collapse
|
20
|
Genome-Wide Identification and Characterization of WD40 Protein Genes in the Silkworm, Bombyx mori. Int J Mol Sci 2018; 19:ijms19020527. [PMID: 29425159 PMCID: PMC5855749 DOI: 10.3390/ijms19020527] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/27/2018] [Accepted: 02/06/2018] [Indexed: 12/18/2022] Open
Abstract
WD40 proteins are scaffolding molecules in protein-protein interactions and play crucial roles in fundamental biological processes. Genome-wide characterization of WD40 proteins in animals has been conducted solely in humans. We retrieved 172 WD40 protein genes in silkworm (BmWD40s) and identified these genes in 7 other insects, 9 vertebrates and 5 nematodes. Comparative analysis revealed that the WD40 protein gene family underwent lineage-specific expansions during animal evolution, but did not undergo significant expansion during insect evolution. The BmWD40s were categorized into five clusters and 12 classes according to the phylogenetic classification and their domain architectures, respectively. Sequence analyses indicated that tandem and segmental duplication played minor roles in producing the current number of BmWD40s, and domain recombination events of multi-domain BmWD40s might have occurred mainly after gene duplication events. Gene Ontology (GO) analysis revealed that a higher proportion of BmWD40s was involved in processes, such as binding, transcription-regulation and cellular component biogenesis, compared to all silkworm genes annotated in GO. Microarray-based analysis demonstrated that many BmWD40s had tissue-specific expression and exhibited high and/or sex-related expression during metamorphosis. These findings contribute to a better understanding of the evolution of the animal WD40 protein family and assist the study of the functions of BmWD40s.
Collapse
|
21
|
Noori AR, Hosseini ES, Nikkhah M, Hosseinkhani S. Apoptosome formation upon overexpression of native and truncated Apaf-1 in cell-free and cell-based systems. Arch Biochem Biophys 2018; 642:46-51. [PMID: 29410086 PMCID: PMC5856089 DOI: 10.1016/j.abb.2018.01.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/17/2018] [Accepted: 01/30/2018] [Indexed: 11/27/2022]
Abstract
Apaf-1 is a cytosolic multi-domain protein in the apoptosis regulatory network. When cytochrome c releases from mitochondria; it binds to WD-40 repeats of Apaf-1 molecule and induces oligomerization of Apaf-1. Here in, a split luciferase assay was used to compare apoptosome formation in cell-free and cell-based systems. This assay uses Apaf-1 tagged with either N-terminal fragment or C-terminal fragment of P. pyralis luciferase. In cell based-system, the apoptosome formation is induced inside the cells which express Apaf-1 tagged with complementary fragments of luciferase while in cell-free system, the apoptosome formation is induced in extracts of the cells. In cell-free system, cytochrome c dependent luciferase activity was observed with full length Apaf-1. However, luciferase activity due to apoptosome formation was much higher in cell based system compared to cell-free system. The truncated Apaf-1 which lacks WD-40 repeats (ΔApaf-1) interacted with endogenous Apaf-1 in a different fashion compared to native form as confirmed by different retention time of eluate in gel filtration and binding to affinity column. The interactions between endogenous Apaf-1 and ΔApaf-1 is stronger than its interaction with native exogenous Apaf-1 as indicated by dominant negative effect of ΔApaf-1 on caspase-3 processing.
Collapse
Affiliation(s)
- Ali Reza Noori
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Elaheh Sadat Hosseini
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maryam Nikkhah
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saman Hosseinkhani
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
| |
Collapse
|
22
|
Caicedo A, Aponte PM, Cabrera F, Hidalgo C, Khoury M. Artificial Mitochondria Transfer: Current Challenges, Advances, and Future Applications. Stem Cells Int 2017; 2017:7610414. [PMID: 28751917 PMCID: PMC5511681 DOI: 10.1155/2017/7610414] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/30/2017] [Accepted: 05/15/2017] [Indexed: 12/18/2022] Open
Abstract
The objective of this review is to outline existing artificial mitochondria transfer techniques and to describe the future steps necessary to develop new therapeutic applications in medicine. Inspired by the symbiotic origin of mitochondria and by the cell's capacity to transfer these organelles to damaged neighbors, many researchers have developed procedures to artificially transfer mitochondria from one cell to another. The techniques currently in use today range from simple coincubations of isolated mitochondria and recipient cells to the use of physical approaches to induce integration. These methods mimic natural mitochondria transfer. In order to use mitochondrial transfer in medicine, we must answer key questions about how to replicate aspects of natural transport processes to improve current artificial transfer methods. Another priority is to determine the optimum quantity and cell/tissue source of the mitochondria in order to induce cell reprogramming or tissue repair, in both in vitro and in vivo applications. Additionally, it is important that the field explores how artificial mitochondria transfer techniques can be used to treat different diseases and how to navigate the ethical issues in such procedures. Without a doubt, mitochondria are more than mere cell power plants, as we continue to discover their potential to be used in medicine.
Collapse
Affiliation(s)
- Andrés Caicedo
- Colegio de Ciencias de la Salud, Escuela de Medicina, Universidad San Francisco de Quito (USFQ), 170901 Quito, Ecuador
- Colegio de Ciencias Biológicas y Ambientales, Instituto de Microbiología, Universidad San Francisco de Quito (USFQ), 170901 Quito, Ecuador
- Mito-Act Research Consortium, Quito, Ecuador
| | - Pedro M. Aponte
- Mito-Act Research Consortium, Quito, Ecuador
- Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito (USFQ), 170901 Quito, Ecuador
| | - Francisco Cabrera
- Mito-Act Research Consortium, Quito, Ecuador
- Colegio de Ciencias de la Salud, Escuela de Medicina Veterinaria, Universidad San Francisco de Quito (USFQ), 170901 Quito, Ecuador
- Institute for Regenerative Medicine and Biotherapy (IRMB), INSERM U1183, 2 Montpellier University, Montpellier, France
| | - Carmen Hidalgo
- Mito-Act Research Consortium, Quito, Ecuador
- Laboratory of Nano-Regenerative Medicine, Faculty of Medicine, Universidad de Los Andes, Santiago, Chile
| | - Maroun Khoury
- Mito-Act Research Consortium, Quito, Ecuador
- Laboratory of Nano-Regenerative Medicine, Faculty of Medicine, Universidad de Los Andes, Santiago, Chile
- Consorcio Regenero, Chilean Consortium for Regenerative Medicine, Santiago, Chile
- Cells for Cells, Santiago, Chile
| |
Collapse
|
23
|
Glushakova OY, Glushakov AA, Wijesinghe DS, Valadka AB, Hayes RL, Glushakov AV. Prospective clinical biomarkers of caspase-mediated apoptosis associated with neuronal and neurovascular damage following stroke and other severe brain injuries: Implications for chronic neurodegeneration. Brain Circ 2017; 3:87-108. [PMID: 30276309 PMCID: PMC6126261 DOI: 10.4103/bc.bc_27_16] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/10/2017] [Accepted: 04/17/2017] [Indexed: 12/11/2022] Open
Abstract
Acute brain injuries, including ischemic and hemorrhagic stroke, as well as traumatic brain injury (TBI), are major worldwide health concerns with very limited options for effective diagnosis and treatment. Stroke and TBI pose an increased risk for the development of chronic neurodegenerative diseases, notably chronic traumatic encephalopathy, Alzheimer's disease, and Parkinson's disease. The existence of premorbid neurodegenerative diseases can exacerbate the severity and prognosis of acute brain injuries. Apoptosis involving caspase-3 is one of the most common mechanisms involved in the etiopathology of both acute and chronic neurological and neurodegenerative diseases, suggesting a relationship between these disorders. Over the past two decades, several clinical biomarkers of apoptosis have been identified in cerebrospinal fluid and peripheral blood following ischemic stroke, intracerebral and subarachnoid hemorrhage, and TBI. These biomarkers include selected caspases, notably caspase-3 and its specific cleavage products such as caspase-cleaved cytokeratin-18, caspase-cleaved tau, and a caspase-specific 120 kDa αII-spectrin breakdown product. The levels of these biomarkers might be a valuable tool for the identification of pathological pathways such as apoptosis and inflammation involved in injury progression, assessment of injury severity, and prediction of clinical outcomes. This review focuses on clinical studies involving biomarkers of caspase-3-mediated pathways, following stroke and TBI. The review further examines their prospective diagnostic utility, as well as clinical utility for improved personalized treatment of stroke and TBI patients and the development of prophylactic treatment chronic neurodegenerative disease.
Collapse
Affiliation(s)
- Olena Y Glushakova
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA, USA
| | - Andriy A Glushakov
- Department of Neurosurgery, University of South Florida College of Medicine, Tampa, FL, USA
| | - Dayanjan S Wijesinghe
- Department of Pharmacotherapy and Outcomes Sciences, Laboratory of Pharmacometabolomics and Companion Diagnostics, Virginia Commonwealth University, Richmond, VA, USA
| | - Alex B Valadka
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA, USA
| | - Ronald L Hayes
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA, USA
- Banyan Biomarkers, Inc., Alachua, 32615, USA
| | | |
Collapse
|
24
|
Zaker F, Nasiri N, Amirizadeh N, Razavi SM, Yaghmaie M, Teimoori-Toolabi L, Maleki A, Bakhshayesh M. Aberrant Methylation-Mediated Suppression of APAF1 in Myelodysplastic Syndrome. Int J Hematol Oncol Stem Cell Res 2017; 11:114-120. [PMID: 28875006 PMCID: PMC5575724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Background: Myelodysplastic syndromes (MDSs) include a diverse group of clonal bone marrow disorders characterized by ineffective hematopoiesis and pancytopenia. It was found that down regulation of APAF1, a putative tumor suppressor gene (TSG), leads to resistance to chemotherapy and disease development in some cancers. In this study, we investigated the relation of APAF1 methylation status with its expression and clinicopathological factors in myelodysplastic syndrome (MDS) patients. Materials andMethods: Methylation Sensitive-High Resolution Melting Curve Analysis (MS-HRM) was employed in studying the methylation of CpG islands in the APAF1promoter region in MDS. Gene expression was analyzed by using real time RT-PCR. Results: 42.6% of patient samples were methylated in promoter region of APAF1analyzed, while methylation of the gene was not seen in controls (P<0.05). Methylation of APAF1was significantly associated with the suppression of its mRNA expression (P=0.00). The methylation status of APAF1in advanced-stage MDS patients (80%) was significantly higher than that of the early-stage MDS patients (28.2%) (P=0.001). The difference in frequency of hypermethylatedAPAF1 gene was significant between good (37.5%) and poor (85.71%) cytogenetic risk groups (P=0.043). In addition, a higher frequency of APAF1hypermethylation was observed in higher-risk MDS group (69.2%) compared to lower-risk MDS group (34.14%) (P=0.026). Conclusion: Our study indicated that APAF1hypermethylation in MDS was associated to high-risk disease classified according to the IPSS, WHO and cytogenetic risk.
Collapse
Affiliation(s)
- Farhad Zaker
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran,Dept. of Hematology, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Nahid Nasiri
- Dept. of Hematology, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Naser Amirizadeh
- Blood Transfusion Research Center, High Institute for Education and Research in Transfusion Medicine, Tehran, Iran
| | - Seyed Mohsen Razavi
- Hematology and Oncology Department, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Marjan Yaghmaie
- Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Science, Tehran, Iran
| | - Ladan Teimoori-Toolabi
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Ali Maleki
- Dept of Hematology, School of Allied Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoumeh Bakhshayesh
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
25
|
Abstract
Dying cells have an important role in the initiation of CD8+ T cell-mediated immunity. The cross-presentation of antigens derived from dying cells enables dendritic cells to present exogenous tissue-restricted or tumour-restricted proteins on MHC class I molecules. Importantly, this pathway has been implicated in multiple autoimmune diseases and accounts for the priming of tumour antigen-specific T cells. Recent data have revealed that in addition to antigen, dying cells provide inflammatory and immunogenic signals that determine the efficiency of CD8+ T cell cross-priming. The complexity of these signals has been evidenced by the multiple molecular pathways that result in cell death and that have now been shown to differentially influence antigen transfer and immunity. In this Review, we provide a detailed summary of both the passive and active signals that are generated by dying cells during their initiation of CD8+ T cell-mediated immunity. We propose that molecules generated alongside cell death pathways - inducible damage-associated molecular patterns (iDAMPs) - are upstream immunological cues that actively regulate adaptive immunity.
Collapse
|
26
|
Shakeri R, Kheirollahi A, Davoodi J. Apaf-1: Regulation and function in cell death. Biochimie 2017; 135:111-125. [PMID: 28192157 DOI: 10.1016/j.biochi.2017.02.001] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/01/2017] [Accepted: 02/02/2017] [Indexed: 01/08/2023]
Abstract
Apoptosis, a form of programmed cell death, is responsible for eliminating damaged or unnecessary cells in multicellular organisms. Various types of intracellular stress trigger apoptosis by induction of cytochrome c release from mitochondria into the cytosol. Apoptotic protease activating factor-1 (Apaf-1) is a key molecule in the intrinsic or mitochondrial pathway of apoptosis, which oligomerizes in response to cytochrome c release and forms a large complex known as apoptosome. Procaspase-9, an initiator caspase in the mitochondrial pathway, is recruited and activated by the apoptosome leading to downstream caspase-3 processing. Various cellular proteins and small molecules can modulate apoptosome formation and function directly or indirectly. Despite recent progress in understanding the mitochondrial pathway of apoptosis, numerous questions such as the molecular mechanism of Apaf-1 oligomerization and caspase-9 activation remain poorly understood. In addition, reports have emerged showing non-apoptotic functions for Apaf-1. The current review summarizes the latest findings regarding structure-function relationship of Apaf-1 as well as its modifiers.
Collapse
Affiliation(s)
- Raheleh Shakeri
- Department of Biological Science and Biotechnology, Faculty of Science, University of Kurdistan, Sanandaj, Iran
| | - Asma Kheirollahi
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Science, Tehran, Iran
| | - Jamshid Davoodi
- Institute of Biochemistry and Biophysics, Department of Biochemistry, University of Tehran, Tehran, Iran.
| |
Collapse
|
27
|
Mechanistic insights into caspase-9 activation by the structure of the apoptosome holoenzyme. Proc Natl Acad Sci U S A 2017; 114:1542-1547. [PMID: 28143931 DOI: 10.1073/pnas.1620626114] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Mammalian intrinsic apoptosis requires activation of the initiator caspase-9, which then cleaves and activates the effector caspases to execute cell killing. The heptameric Apaf-1 apoptosome is indispensable for caspase-9 activation by together forming a holoenzyme. The molecular mechanism of caspase-9 activation remains largely enigmatic. Here, we report the cryoelectron microscopy (cryo-EM) structure of an apoptotic holoenzyme and structure-guided biochemical analyses. The caspase recruitment domains (CARDs) of Apaf-1 and caspase-9 assemble in two different ways: a 4:4 complex docks onto the central hub of the apoptosome, and a 2:1 complex binds the periphery of the central hub. The interface between the CARD complex and the central hub is required for caspase-9 activation within the holoenzyme. Unexpectedly, the CARD of free caspase-9 strongly inhibits its proteolytic activity. These structural and biochemical findings demonstrate that the apoptosome activates caspase-9 at least in part through sequestration of the inhibitory CARD domain.
Collapse
|
28
|
Structural Insights into DD-Fold Assembly and Caspase-9 Activation by the Apaf-1 Apoptosome. Structure 2017; 25:407-420. [PMID: 28111022 DOI: 10.1016/j.str.2016.12.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/19/2016] [Accepted: 12/30/2016] [Indexed: 01/07/2023]
Abstract
Death domain (DD)-fold assemblies play a crucial role in regulating the signaling to cell survival or death. Here we report the crystal structure of the caspase recruitment domain (CARD)-CARD disk of the human apoptosome. The structure surprisingly reveals that three 1:1 Apaf-1:procaspase-9 CARD protomers form a novel helical DD-fold assembly on the heptameric wheel-like platform of the apoptosome. The small-angle X-ray scattering and multi-angle light scattering data also support that three protomers could form an oligomeric complex similar to the crystal structure. Interestingly, the quasi-equivalent environment of CARDs could generate different quaternary CARD assemblies. We also found that the type II interaction is conserved in all DD-fold complexes, whereas the type I interaction is found only in the helical DD-fold assemblies. This study provides crucial insights into the caspase activation mechanism, which is tightly controlled by a sophisticated and highly evolved CARD assembly on the apoptosome, and also enables better understanding of the intricate DD-fold assembly.
Collapse
|
29
|
Cheng TC, Akey IV, Yuan S, Yu Z, Ludtke SJ, Akey CW. A Near-Atomic Structure of the Dark Apoptosome Provides Insight into Assembly and Activation. Structure 2016; 25:40-52. [PMID: 27916517 DOI: 10.1016/j.str.2016.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/11/2016] [Accepted: 10/27/2016] [Indexed: 11/19/2022]
Abstract
In Drosophila, the Apaf-1-related killer (Dark) forms an apoptosome that activates procaspases. To investigate function, we have determined a near-atomic structure of Dark double rings using cryo-electron microscopy. We then built a nearly complete model of the apoptosome that includes 7- and 8-blade β-propellers. We find that the preference for dATP during Dark assembly may be governed by Ser325, which is in close proximity to the 2' carbon of the deoxyribose ring. Interestingly, β-propellers in V-shaped domains of the Dark apoptosome are more widely separated, relative to these features in the Apaf-1 apoptosome. This wider spacing may be responsible for the lack of cytochrome c binding to β-propellers in the Dark apoptosome. Our structure also highlights the roles of two loss-of-function mutations that may block Dark assembly. Finally, the improved model provides a framework to understand apical procaspase activation in the intrinsic cell death pathway.
Collapse
Affiliation(s)
- Tat Cheung Cheng
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
| | - Ildikó V Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
| | - Shujun Yuan
- Department of Biologics Research - Protein Sciences, U.S. Innovation Center, Bayer Healthcare, 455 Mission Bay Boulevard South, San Francisco, CA 94158, USA
| | - Zhiheng Yu
- Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Steven J Ludtke
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Christopher W Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
| |
Collapse
|
30
|
Cheng TC, Hong C, Akey IV, Yuan S, Akey CW. A near atomic structure of the active human apoptosome. eLife 2016; 5. [PMID: 27697150 PMCID: PMC5050015 DOI: 10.7554/elife.17755] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/12/2016] [Indexed: 01/19/2023] Open
Abstract
In response to cell death signals, an active apoptosome is assembled from Apaf-1 and procaspase-9 (pc-9). Here we report a near atomic structure of the active human apoptosome determined by cryo-electron microscopy. The resulting model gives insights into cytochrome c binding, nucleotide exchange and conformational changes that drive assembly. During activation an acentric disk is formed on the central hub of the apoptosome. This disk contains four Apaf-1/pc-9 CARD pairs arranged in a shallow spiral with the fourth pc-9 CARD at lower occupancy. On average, Apaf-1 CARDs recruit 3 to 5 pc-9 molecules to the apoptosome and one catalytic domain may be parked on the hub, when an odd number of zymogens are bound. This suggests a stoichiometry of one or at most, two pc-9 dimers per active apoptosome. Thus, our structure provides a molecular framework to understand the role of the apoptosome in programmed cell death and disease. DOI:http://dx.doi.org/10.7554/eLife.17755.001 An adult human loses around 50–70 billion cells every day via a process termed apoptosis. The term arises from the Greek word that describes leaves “falling off” a tree, and the process entails damaged or unwanted cells essentially committing suicide in a controlled manner. As such, apoptosis keeps the number of cells in tissues and organs in check. It also allows components of old cells to be recycled to make new ones. In cells that are targeted to die, a protein called cytochrome c interacts with another protein, named Apaf-1, together with a nucleotide triphosphate molecule. These steps work in concert to trigger the assembly of the apoptosome: a large wheel-like complex that contains seven copies each of Apaf-1 and cytochrome c. The central hub of the wheel then recruits a specific protein-cutting enzyme, which once activated sets in motion a cascade of events that dismantle the cell from the inside out. Cheng et al. now use an electron microscope to reveal the three-dimensional structure of the active human apoptosome, in enough detail to determine the positions of many of the amino acids that make up the complex. The three dimensional model provides new insights into how Apaf-1 changes shape as the complex assembles in the presence of cytochrome c and nucleotide triphosphate. Cheng et al. went on to reveal a disk-like structure made from the parts of four Apaf-1 proteins that interact with the protein-cutting enzymes. This disk forms a spiral that sits atop the central hub of the wheel-like apoptosome. Finally, the findings suggest that, although the wheel like complex has seven spokes, at any one time the active apoptosome may only need two (or at most four) copies of the protein-cutting enzyme to trigger the cascade of events that lead to cell death In the future, emerging technologies may provide high enough resolution to visualize fine details of the interactions between cytochrome c and Apaf-1, and reveal more about the disk-like spiral as well. This in turn will give a better understanding of how the apoptosome assembles and how the protein-cutting enzyme becomes activated. DOI:http://dx.doi.org/10.7554/eLife.17755.002
Collapse
Affiliation(s)
- Tat Cheung Cheng
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, United States
| | - Chuan Hong
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Ildikó V Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, United States
| | - Shujun Yuan
- Department of Biologics Research - Protein Sciences, U.S. Innovation Center, Bayer Healthcare, San Franciso, United States
| | - Christopher W Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, United States
| |
Collapse
|
31
|
Caria S, Marshall B, Burton RL, Campbell S, Pantaki-Eimany D, Hawkins CJ, Barry M, Kvansakul M. The N Terminus of the Vaccinia Virus Protein F1L Is an Intrinsically Unstructured Region That Is Not Involved in Apoptosis Regulation. J Biol Chem 2016; 291:14600-8. [PMID: 27151220 DOI: 10.1074/jbc.m116.726851] [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] [Received: 03/15/2016] [Indexed: 12/21/2022] Open
Abstract
Subversion of host cell apoptotic responses is a prominent feature of viral immune evasion strategies to prevent premature clearance of infected cells. Numerous poxviruses encode structural and functional homologs of the Bcl-2 family of proteins, and vaccinia virus harbors antiapoptotic F1L that potently inhibits the mitochondrial apoptotic checkpoint. Recently F1L has been assigned a caspase-9 inhibitory function attributed to an N-terminal α helical region of F1L spanning residues 1-15 (1) preceding the domain-swapped Bcl-2-like domains. Using a reconstituted caspase inhibition assay in yeast we found that unlike AcP35, a well characterized caspase-9 inhibitor from the insect virus Autographa californica multiple nucleopolyhedrovirus, F1L does not prevent caspase-9-mediated yeast cell death. Furthermore, we found that deletion of the F1L N-terminal region does not impede F1L antiapoptotic activity in the context of a viral infection. Solution analysis of the F1L N-terminal regions using small angle x-ray scattering indicates that the region of F1L spanning residues 1-50 located N-terminally from the Bcl-2 fold is an intrinsically unstructured region. We conclude that the N terminus of F1L is not involved in apoptosis inhibition and may act as a regulatory element in other signaling pathways in a manner reminiscent of other unstructured regulatory elements commonly found in mammalian prosurvival Bcl-2 members including Bcl-xL and Mcl-1.
Collapse
Affiliation(s)
- Sofia Caria
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Bevan Marshall
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Robyn-Lee Burton
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Stephanie Campbell
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Delara Pantaki-Eimany
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Christine J Hawkins
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| | - Michele Barry
- Li Ka Shing Institute for Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | - Marc Kvansakul
- From the La Trobe Institute for Molecular Science, Department of Biochemistry and Genetics, La Trobe University, Victoria 3086, Australia and
| |
Collapse
|
32
|
Joseph AP, Malhotra S, Burnley T, Wood C, Clare DK, Winn M, Topf M. Refinement of atomic models in high resolution EM reconstructions using Flex-EM and local assessment. Methods 2016; 100:42-9. [PMID: 26988127 PMCID: PMC4854230 DOI: 10.1016/j.ymeth.2016.03.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/09/2016] [Accepted: 03/14/2016] [Indexed: 01/19/2023] Open
Abstract
As the resolutions of Three Dimensional Electron Microscopic reconstructions of biological macromolecules are being improved, there is a need for better fitting and refinement methods at high resolutions and robust approaches for model assessment. Flex-EM/MODELLER has been used for flexible fitting of atomic models in intermediate-to-low resolution density maps of different biological systems. Here, we demonstrate the suitability of the method to successfully refine structures at higher resolutions (2.5-4.5Å) using both simulated and experimental data, including a newly processed map of Apo-GroEL. A hierarchical refinement protocol was adopted where the rigid body definitions are relaxed and atom displacement steps are reduced progressively at successive stages of refinement. For the assessment of local fit, we used the SMOC (segment-based Manders' overlap coefficient) score, while the model quality was checked using the Qmean score. Comparison of SMOC profiles at different stages of refinement helped in detecting regions that are poorly fitted. We also show how initial model errors can have significant impact on the goodness-of-fit. Finally, we discuss the implementation of Flex-EM in the CCP-EM software suite.
Collapse
Affiliation(s)
- Agnel Praveen Joseph
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London WC1E 7HX, United Kingdom
| | - Sony Malhotra
- Scientific Computing Department, Science and Technology Facilities Council, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
| | - Tom Burnley
- Scientific Computing Department, Science and Technology Facilities Council, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
| | - Chris Wood
- Scientific Computing Department, Science and Technology Facilities Council, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
| | - Daniel K Clare
- Electron Bio-Imaging Centre (eBIC), Diamond Light Source, Harwell Science & Innovation Campus, OX11 0DE, United Kingdom
| | - Martyn Winn
- Scientific Computing Department, Science and Technology Facilities Council, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom.
| | - Maya Topf
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London WC1E 7HX, United Kingdom.
| |
Collapse
|
33
|
Wang C, Dong X, Han L, Su XD, Zhang Z, Li J, Song J. Identification of WD40 repeats by secondary structure-aided profile-profile alignment. J Theor Biol 2016; 398:122-9. [PMID: 27021623 DOI: 10.1016/j.jtbi.2016.03.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 01/20/2016] [Accepted: 03/16/2016] [Indexed: 12/31/2022]
Abstract
A WD40 protein typically contains four or more repeats of ~40 residues ended with the Trp-Asp dipeptide, which folds into β-propellers with four β strands in each repeat. They often function as scaffolds for protein-protein interactions and are involved in numerous fundamental biological processes. Despite their important functional role, the "velcro" closure of WD40 propellers and the diversity of WD40 repeats make their identification a difficult task. Here we develop a new WD40 Repeat Recognition method (WDRR), which uses predicted secondary structure information to generate candidate repeat segments, and further employs a profile-profile alignment to identify the correct WD40 repeats from candidate segments. In particular, we design a novel alignment scoring function that combines dot product and BLOSUM62, thereby achieving a great balance of sensitivity and accuracy. Taking advantage of these strategies, WDRR could effectively reduce the false positive rate and accurately identify more remote homologous WD40 repeats with precise repeat boundaries. We further use WDRR to re-annotate the Pfam families in the β-propeller clan (CL0186) and identify a number of WD40 repeat proteins with high confidence across nine model organisms. The WDRR web server and the datasets are available at http://protein.cau.edu.cn/wdrr/.
Collapse
Affiliation(s)
- Chuan Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.
| | - Xiaobao Dong
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
| | - Lei Han
- Center for Cancer Molecular Diagnosis, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, China.
| | - Xiao-Dong Su
- State Key Laboratory of Protein and Plant Gene Research and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China.
| | - Ziding Zhang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
| | - Jinyan Li
- Advanced Analytics Institute and Centre for Health Technologies, University of Technology Sydney, 81 Broadway, Sydney, NSW 2007, Australia.
| | - Jiangning Song
- National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Faculty of Medicine, Monash University, Melbourne, VIC 3800, Australia; Monash Centre for Data Science, Faculty of Information Technology, Monash University, Melbourne, VIC 3800, Australia.
| |
Collapse
|
34
|
Kwon SB, Kim MJ, Yang JM, Lee HP, Hong JT, Jeong HS, Kim ES, Yoon DY. Cudrania tricuspidata Stem Extract Induces Apoptosis via the Extrinsic Pathway in SiHa Cervical Cancer Cells. PLoS One 2016; 11:e0150235. [PMID: 26960190 PMCID: PMC4784787 DOI: 10.1371/journal.pone.0150235] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/10/2016] [Indexed: 01/06/2023] Open
Abstract
The focus of this study is the anti-cancer effects of Cudrania tricuspidata stem (CTS) extract on cervical cancer cells. The effect of CTS on cell viability was investigated in HPV-positive cervical cancer cells and HaCaT human normal keratinocytes. CTS showed significant dose-dependent cytotoxic effects in cervical cancer cells. However, there was no cytotoxic effect of CTS on HaCaT keratinocytes at concentrations of 0.125-0.5 mg/mL. Based on this cytotoxic effect, we demonstrated that CTS induced apoptosis by down-regulating the E6 and E7 viral oncogenes. Apoptosis was detected by DAPI staining, annexin V-FITC/PI staining, cell cycle analysis, western blotting, RT-PCR, and JC-1 staining in SiHa cervical cancer cells. The mRNA expression levels of extrinsic pathway molecules such as Fas, death receptor 5 (DR5), and TNF-related apoptosis-inducing ligand (TRAIL) were increased by CTS. Furthermore, CTS treatment activated caspase-3/caspase-8 and cleavage of poly (ADP-ribose) polymerase (PARP). However, the mitochondrial membrane potential and expression levels of intrinsic pathway molecules such as Bcl-2, Bcl-xL, Bax, and cytochrome C were not modulated by CTS. Taken together, these results indicate that CTS induced apoptosis by activating the extrinsic pathway, but not the intrinsic pathway, in SiHa cervical cancer cells. These results suggest that CTS can be used as a modulating agent in cervical cancer.
Collapse
Affiliation(s)
- Sae-Bom Kwon
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, Korea
| | - Min-Je Kim
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, Korea
| | - Jin Mo Yang
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, Korea
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, United States of America
| | - Hee-Pom Lee
- College of Pharmacy, Medical Research Center, Chungbuk National University, Osong, Chungbuk, Korea
| | - Jin Tae Hong
- College of Pharmacy, Medical Research Center, Chungbuk National University, Osong, Chungbuk, Korea
| | - Heon-Sang Jeong
- Agriculture, Life and Environments Sciences, Chungbuk National University, Cheongju, Chungbuk, Korea
| | - Eun Suk Kim
- Chungcheongbukdo Bio CS, Osong, Chungbuk, Korea
| | - Do-Young Yoon
- Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, Korea
- * E-mail:
| |
Collapse
|
35
|
Abstract
Inflammasomes are oligomeric signaling complexes that promote caspase activation and maturation of proinflammatory cytokines. Structural and biophysical studies have shed light on the mechanisms of nucleic acid recognition and signaling complex assembly involving the AIM2 (absent in myeloma 2) and IFI16 (γ-interferon-inducible protein 16) inflammasomes. However, our understanding of the mechanisms of the NLRP3 (nucleotide-binding oligomerization-like receptor family, pyrin domain-containing protein 3) activation, either by nucleic acids or by other reported stimuli, has remained elusive. Exciting recent progress on the filament formation by the ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain) pyrin domain and the IFI16-double stranded DNA complex has established that the formation of higher order polymers is one of the general mechanisms for signaling platform assembly in innate immune system. The paradigm-changing discovery of the extracellular function of the NLRP3-ASC inflammasome has opened the door for therapeutic targeting the inflammasome filament formation for various clinical conditions. Future characterization of the canonical and non-canonical inflammasome complexes will undoubtedly reveal more surprises on their structure and function and enrich our understanding of the molecular mechanisms of ligand recognition, activation, and regulation.
Collapse
Affiliation(s)
- Tsan Sam Xiao
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| |
Collapse
|
36
|
Abstract
In multicellular organisms, cell death is a critical and active process that maintains tissue homeostasis and eliminates potentially harmful cells. There are three major types of morphologically distinct cell death: apoptosis (type I cell death), autophagic cell death (type II), and necrosis (type III). All three can be executed through distinct, and sometimes overlapping, signaling pathways that are engaged in response to specific stimuli. Apoptosis is triggered when cell-surface death receptors such as Fas are bound by their ligands (the extrinsic pathway) or when Bcl2-family proapoptotic proteins cause the permeabilization of the mitochondrial outer membrane (the intrinsic pathway). Both pathways converge on the activation of the caspase protease family, which is ultimately responsible for the dismantling of the cell. Autophagy defines a catabolic process in which parts of the cytosol and specific organelles are engulfed by a double-membrane structure, known as the autophagosome, and eventually degraded. Autophagy is mostly a survival mechanism; nevertheless, there are a few examples of autophagic cell death in which components of the autophagic signaling pathway actively promote cell death. Necrotic cell death is characterized by the rapid loss of plasma membrane integrity. This form of cell death can result from active signaling pathways, the best characterized of which is dependent on the activity of the protein kinase RIP3.
Collapse
Affiliation(s)
- Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Fabien Llambi
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| |
Collapse
|
37
|
Wu L, Yang W, Zhang SN, Lu JB. Alpinetin inhibits lung cancer progression and elevates sensitization drug-resistant lung cancer cells to cis-diammined dichloridoplatium. Drug Des Devel Ther 2015; 9:6119-27. [PMID: 26604699 PMCID: PMC4655908 DOI: 10.2147/dddt.s92702] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Alpinetin is a novel flavonoid that has demonstrated potent antitumor activity in previous studies. However, the efficacy and mechanism of alpinetin in treating lung cancer have not been determined. METHODS We evaluated the impact of different doses and durations of alpinetin treatment on the cell proliferation, the apoptosis of lung cancer cells, as well as the drug-resistant lung cancer cells. RESULTS This study showed that the alpinetin inhibited the cell proliferation, enhanced the apoptosis, and inhibited the PI3K/Akt signaling in lung cancer cells. Moreover, alpinetin significantly increased the sensitivity of drug-resistant lung cancer cells to the chemotherapeutic effect of cis-diammined dichloridoplatium. Taken together, this study demonstrated that alpinetin significantly suppressed the development of human lung cancer possibly by influencing mitochondria and the PI3K/Akt signaling pathway and sensitized drug-resistant lung cancer cells. CONCLUSION Alpinetin may be used as a potential compound for combinatorial therapy or as a complement to other chemotherapeutic agents when multiple lines of treatments have failed to reduce lung cancer.
Collapse
Affiliation(s)
- Lin Wu
- Department of Thoracic Surgery, Sheng Jing Hospital of China Medical University, Shenyang, People’s Republic of China
| | - Wei Yang
- Department of Thoracic Surgery, Sheng Jing Hospital of China Medical University, Shenyang, People’s Republic of China
| | - Su-ning Zhang
- Department of Thoracic Surgery, Sheng Jing Hospital of China Medical University, Shenyang, People’s Republic of China
| | - Ji-bin Lu
- Department of Thoracic Surgery, Sheng Jing Hospital of China Medical University, Shenyang, People’s Republic of China
| |
Collapse
|
38
|
Diebolder CA, Halff EF, Koster AJ, Huizinga EG, Koning RI. Cryoelectron Tomography of the NAIP5/NLRC4 Inflammasome: Implications for NLR Activation. Structure 2015; 23:2349-2357. [PMID: 26585513 DOI: 10.1016/j.str.2015.10.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 09/24/2015] [Accepted: 10/01/2015] [Indexed: 10/22/2022]
Abstract
Inflammasomes are high molecular weight protein complexes that play a crucial role in innate immunity by activating caspase-1. Inflammasome formation is initiated when molecules originating from invading microorganisms activate nucleotide-binding domain and leucine-rich repeat-containing receptors (NLRs) and induce NLR multimerization. Little is known about the conformational changes involved in NLR activation and the structural organization of NLR multimers. Here, we show by cryoelectron tomography that flagellin-induced NAIP5/NLRC4 multimers form right- and left-handed helical polymers with a diameter of 28 nm and a pitch of 6.5 nm. Subtomogram averaging produced an electron density map at 4 nm resolution, which was used for rigid body fitting of NLR subdomains derived from the crystal structure of dormant NLRC4. The resulting structural model of inflammasome-incorporated NLRC4 indicates that a prominent rotation of the LRR domain of NLRC4 is necessary for multimer formation, providing unprecedented insight into the conformational changes that accompany NLR activation.
Collapse
Affiliation(s)
- Christoph A Diebolder
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, the Netherlands; Crystal and Structural Chemistry, Department of Chemistry, Faculty of Science, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Els F Halff
- Crystal and Structural Chemistry, Department of Chemistry, Faculty of Science, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Abraham J Koster
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, the Netherlands
| | - Eric G Huizinga
- Crystal and Structural Chemistry, Department of Chemistry, Faculty of Science, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Roman I Koning
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, the Netherlands.
| |
Collapse
|
39
|
Zhou M, Li Y, Hu Q, Bai XC, Huang W, Yan C, Scheres SHW, Shi Y. Atomic structure of the apoptosome: mechanism of cytochrome c- and dATP-mediated activation of Apaf-1. Genes Dev 2015; 29:2349-61. [PMID: 26543158 PMCID: PMC4691890 DOI: 10.1101/gad.272278.115] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 10/13/2015] [Indexed: 12/11/2022]
Abstract
In this study, Zhou et al. report the first atomic structure of the mammalian apoptosome, determined at 3.8 Å resolution by cryo-electron microscopy. These findings provide novel insight into how CytC relieves the autoinhibition of Apaf-1 and how dATP triggers Apaf-1 oligomerization. The apoptotic protease-activating factor 1 (Apaf-1) controls the onset of many known forms of intrinsic apoptosis in mammals. Apaf-1 exists in normal cells as an autoinhibited monomer. Upon binding to cytochrome c and dATP, Apaf-1 oligomerizes into a heptameric complex known as the apoptosome, which recruits and activates cell-killing caspases. Here we present an atomic structure of an intact mammalian apoptosome at 3.8 Å resolution, determined by single-particle, cryo-electron microscopy (cryo-EM). Structural analysis, together with structure-guided biochemical characterization, uncovered how cytochrome c releases the autoinhibition of Apaf-1 through specific interactions with the WD40 repeats. Structural comparison with autoinhibited Apaf-1 revealed how dATP binding triggers a set of conformational changes that results in the formation of the apoptosome. Together, these results constitute the molecular mechanism of cytochrome c- and dATP-mediated activation of Apaf-1.
Collapse
Affiliation(s)
- Mengying Zhou
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Yini Li
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Qi Hu
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xiao-Chen Bai
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Weiyun Huang
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Chuangye Yan
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Sjors H W Scheres
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Yigong Shi
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| |
Collapse
|
40
|
Structure and function of legumain in health and disease. Biochimie 2015; 122:126-50. [PMID: 26403494 DOI: 10.1016/j.biochi.2015.09.022] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/18/2015] [Indexed: 12/27/2022]
Abstract
The last years have seen a steady increase in our understanding of legumain biology that is driven from two largely uncoupled research arenas, the mammalian and the plant legumain field. Research on legumain, which is also referred to as asparaginyl endopeptidase (AEP) or vacuolar processing enzyme (VPE), is slivered, however. Here we summarise recent important findings and put them into a common perspective. Legumain is usually associated with its cysteine endopeptidase activity in lysosomes where it contributes to antigen processing for class II MHC presentation. However, newly recognized functions disperse previously assumed boundaries with respect to their cellular compartmentalisation and enzymatic activities. Legumain is also found extracellularly and even translocates to the cytosol and the nucleus, with seemingly incompatible pH and redox potential. These different milieus translate into changes of legumain's molecular properties, including its (auto-)activation, conformational stability and enzymatic functions. Contrasting its endopeptidase activity, legumain can develop a carboxypeptidase activity which remains stable at neutral pH. Moreover, legumain features a peptide ligase activity, with intriguing mechanistic peculiarities in plant and human isoforms. In pathological settings, such as cancer or Alzheimer's disease, the proper association of legumain activities with the corresponding cellular compartments is breached. Legumain's increasingly recognized physiological and pathological roles also indicate future research opportunities in this vibrant field.
Collapse
|
41
|
Shakeri R, Hosseinkhani S, Los MJ, Davoodi J, Jain MV, Cieślar-Pobuda A, Rafat M, Ardestani SK. Role of the salt bridge between glutamate 546 and arginine 907 in preservation of autoinhibited form of Apaf-1. Int J Biol Macromol 2015; 81:370-4. [PMID: 26277751 DOI: 10.1016/j.ijbiomac.2015.08.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 08/09/2015] [Accepted: 08/10/2015] [Indexed: 11/18/2022]
Abstract
Apaf-1, the key element of apoptotic mitochondrial pathway, normally exists in an auto-inhibited form inside the cytosol. WRD-domain of Apaf-1 has a critical role in the preservation of auto-inhibited form; however the underlying mechanism is unclear. It seems the salt bridges between WRD and NOD domains are involved in maintaining the inactive conformation of Apaf-1. At the present study, we have investigated the effect of E546-R907 salt bridge on the maintenance of auto-inhibited form of human Apaf-1. E546 is mutated to glutamine (Q) and arginine (R). Over-expression of wild type Apaf-1 and its E546Q and E546R variants in HEK293T cells does not induce apoptosis unlike - HL-60 cancer cell line. In vitro apoptosome formation assay showed that all variants are cytochrome c and dATP dependent to form apoptosome and activate endogenous procaspase-9 in Apaf-1-knockout MEF cell line. These results suggest that E546 is not a critical residue for preservation of auto-inhibited Apaf-1. Furthermore, the behavior of Apaf-1 variants for in vitro apoptosome formation in HEK293T cell is similar to exogenous wild type Apaf-1. Wild type and its variants can form apoptosome in HEK293T cell with different procaspase-3 processing pattern in the presence and absence of exogenous cytochrome c and dATP.
Collapse
Affiliation(s)
- Raheleh Shakeri
- Institute of Biochemistry and Biophysics, Department of Biochemistry, University of Tehran, Tehran, Iran
| | - Saman Hosseinkhani
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Marek J Los
- Department of Clinical & Experimental Medicine (IKE), Division of Cell Biology, Integrative Regenerative Med. Center (IGEN), Linköping University, Linköping, Sweden; Department of Pathology, Pomeranian Medical University, Szczecin, Poland
| | - Jamshid Davoodi
- Institute of Biochemistry and Biophysics, Department of Biochemistry, University of Tehran, Tehran, Iran
| | - Mayur V Jain
- Department of Clinical & Experimental Medicine (IKE), Division of Cell Biology, Integrative Regenerative Med. Center (IGEN), Linköping University, Linköping, Sweden
| | - Artur Cieślar-Pobuda
- Department of Clinical & Experimental Medicine (IKE), Division of Cell Biology, Integrative Regenerative Med. Center (IGEN), Linköping University, Linköping, Sweden; Institute of Automatic Control, Silesian University of Technology, Gliwice, Poland
| | - Mehrdad Rafat
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | | |
Collapse
|
42
|
Shalaeva DN, Dibrova DV, Galperin MY, Mulkidjanian AY. Modeling of interaction between cytochrome c and the WD domains of Apaf-1: bifurcated salt bridges underlying apoptosome assembly. Biol Direct 2015. [PMID: 26014357 DOI: 10.1186/s13062-015-0059- 4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Binding of cytochrome c, released from the damaged mitochondria, to the apoptotic protease activating factor 1 (Apaf-1) is a key event in the apoptotic signaling cascade. The binding triggers a major domain rearrangement in Apaf-1, which leads to oligomerization of Apaf-1/cytochrome c complexes into an apoptosome. Despite the availability of crystal structures of cytochrome c and Apaf-1 and cryo-electron microscopy models of the entire apoptosome, the binding mode of cytochrome c to Apaf-1, as well as the nature of the amino acid residues of Apaf-1 involved remain obscure. RESULTS We investigated the interaction between cytochrome c and Apaf-1 by combining several modeling approaches. We have applied protein-protein docking and energy minimization, evaluated the resulting models of the Apaf-1/cytochrome c complex, and carried out a further analysis by means of molecular dynamics simulations. We ended up with a single model structure where all the lysine residues of cytochrome c that are known as functionally-relevant were involved in forming salt bridges with acidic residues of Apaf-1. This model has revealed three distinctive bifurcated salt bridges, each involving a single lysine residue of cytochrome c and two neighboring acidic resides of Apaf-1. Salt bridge-forming amino acids of Apaf-1 showed a clear evolutionary pattern within Metazoa, with pairs of acidic residues of Apaf-1, involved in bifurcated salt bridges, reaching their highest numbers in the sequences of vertebrates, in which the cytochrome c-mediated mechanism of apoptosome formation seems to be typical. CONCLUSIONS The reported model of an Apaf-1/cytochrome c complex provides insights in the nature of protein-protein interactions which are hard to observe in crystallographic or electron microscopy studies. Bifurcated salt bridges can be expected to be stronger than simple salt bridges, and their formation might promote the conformational change of Apaf-1, leading to the formation of an apoptosome. Combination of structural and sequence analyses provides hints on the evolution of the cytochrome c-mediated apoptosis.
Collapse
Affiliation(s)
- Daria N Shalaeva
- School of Physics, Osnabrück University, 49069, Osnabrück, Germany. .,School of Bioengineering and Bioinformatics, 117999, Moscow, Russia.
| | - Daria V Dibrova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 117999, Moscow, Russia.
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 20894, Bethesda, MD, USA.
| | - Armen Y Mulkidjanian
- School of Physics, Osnabrück University, 49069, Osnabrück, Germany. .,School of Bioengineering and Bioinformatics, 117999, Moscow, Russia. .,A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 117999, Moscow, Russia.
| |
Collapse
|
43
|
Shalaeva DN, Dibrova DV, Galperin MY, Mulkidjanian AY. Modeling of interaction between cytochrome c and the WD domains of Apaf-1: bifurcated salt bridges underlying apoptosome assembly. Biol Direct 2015; 10:29. [PMID: 26014357 PMCID: PMC4445527 DOI: 10.1186/s13062-015-0059-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 05/13/2015] [Indexed: 12/19/2022] Open
Abstract
Background Binding of cytochrome c, released from the damaged mitochondria, to the apoptotic protease activating factor 1 (Apaf-1) is a key event in the apoptotic signaling cascade. The binding triggers a major domain rearrangement in Apaf-1, which leads to oligomerization of Apaf-1/cytochrome c complexes into an apoptosome. Despite the availability of crystal structures of cytochrome c and Apaf-1 and cryo-electron microscopy models of the entire apoptosome, the binding mode of cytochrome c to Apaf-1, as well as the nature of the amino acid residues of Apaf-1 involved remain obscure. Results We investigated the interaction between cytochrome c and Apaf-1 by combining several modeling approaches. We have applied protein-protein docking and energy minimization, evaluated the resulting models of the Apaf-1/cytochrome c complex, and carried out a further analysis by means of molecular dynamics simulations. We ended up with a single model structure where all the lysine residues of cytochrome c that are known as functionally-relevant were involved in forming salt bridges with acidic residues of Apaf-1. This model has revealed three distinctive bifurcated salt bridges, each involving a single lysine residue of cytochrome c and two neighboring acidic resides of Apaf-1. Salt bridge-forming amino acids of Apaf-1 showed a clear evolutionary pattern within Metazoa, with pairs of acidic residues of Apaf-1, involved in bifurcated salt bridges, reaching their highest numbers in the sequences of vertebrates, in which the cytochrome c-mediated mechanism of apoptosome formation seems to be typical. Conclusions The reported model of an Apaf-1/cytochrome c complex provides insights in the nature of protein-protein interactions which are hard to observe in crystallographic or electron microscopy studies. Bifurcated salt bridges can be expected to be stronger than simple salt bridges, and their formation might promote the conformational change of Apaf-1, leading to the formation of an apoptosome. Combination of structural and sequence analyses provides hints on the evolution of the cytochrome c-mediated apoptosis. Reviewers This article was reviewed by Andrei L. Osterman, Narayanaswamy Srinivasan, Igor N. Berezovsky, and Gerrit Vriend (nominated by Martijn Huynen). Electronic supplementary material The online version of this article (doi:10.1186/s13062-015-0059-4) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Daria N Shalaeva
- School of Physics, Osnabrück University, 49069, Osnabrück, Germany. .,School of Bioengineering and Bioinformatics, 117999, Moscow, Russia.
| | - Daria V Dibrova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 117999, Moscow, Russia.
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 20894, Bethesda, MD, USA.
| | - Armen Y Mulkidjanian
- School of Physics, Osnabrück University, 49069, Osnabrück, Germany. .,School of Bioengineering and Bioinformatics, 117999, Moscow, Russia. .,A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 117999, Moscow, Russia.
| |
Collapse
|
44
|
Phosphanegold(I) thiolates, Ph3PAu[SC(OR)=NC6H4Me-4] for R = Me, Et and iPr, induce apoptosis, cell cycle arrest and inhibit cell invasion of HT-29 colon cancer cells through modulation of the nuclear factor-κB activation pathway and ubiquitination. J Biol Inorg Chem 2015; 20:855-73. [DOI: 10.1007/s00775-015-1271-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 05/10/2015] [Indexed: 11/27/2022]
|
45
|
Azad T, Tashakor A, Rahmati F, Hemmati R, Hosseinkhani S. Oscillation of apoptosome formation through assembly of truncated Apaf-1. Eur J Pharmacol 2015; 760:64-71. [PMID: 25895636 DOI: 10.1016/j.ejphar.2015.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 04/03/2015] [Accepted: 04/08/2015] [Indexed: 02/08/2023]
Abstract
In this study, we used spilt luciferase complementation assay strategy in order to further elucidate the main role of WD-40 repeats of Apaf-1 molecules in apoptosome formation. In the presence of ATP and cytochrome c, Apaf-1 monomers oligomerize and provide a platform for the activation of procaspase-9 and subsequently procaspase-3/7. For a detailed biochemical and structural investigation of Apaf-1 function and apoptosome formation, several studies have been made in recent years. However, many questions related to in vivo evaluation of this phenomenon have been persisting to answer. Some of the most important of these questions are related to WD-40 repeats at the carboxy terminus of Apaf-1 and its function in apoptosome complex formation and caspase activation. When truncated Apaf-1 molecules conjugated with luciferase fragments place in close proximity, light signal emits and real time evaluation of protein-protein interactions becomes possible. Here, we observed, for the first time, the autoassembly of truncated Apaf-1 molecules disappeared after several hours without any caspase-3/7 activation. However, we observed that, truncated Apaf-1 molecules can activate caspase-3/7 upon the induction of apoptosis via doxorubicin. Moreover, oscillation in luciferase activity upon complementation was revealed which implicates the dynamism of apoptosome formation.
Collapse
Affiliation(s)
- Taha Azad
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, P.O.Box: 14115-154, Tehran, Iran
| | - Amin Tashakor
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, P.O.Box: 14115-154, Tehran, Iran
| | - Fereshteh Rahmati
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, P.O.Box: 14115-154, Tehran, Iran
| | - Roohullah Hemmati
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, P.O.Box: 14115-154, Tehran, Iran
| | - Saman Hosseinkhani
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, P.O.Box: 14115-154, Tehran, Iran.
| |
Collapse
|
46
|
Pang Y, Bai XC, Yan C, Hao Q, Chen Z, Wang JW, Scheres SHW, Shi Y. Structure of the apoptosome: mechanistic insights into activation of an initiator caspase from Drosophila. Genes Dev 2015; 29:277-87. [PMID: 25644603 PMCID: PMC4318144 DOI: 10.1101/gad.255877.114] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The autocatalytic activation of an initiator caspase, exemplified by caspase-9 in mammals or its ortholog, Dronc, in fruit flies, is facilitated by a multimeric adaptor complex known as the apoptosome. Pang et al. report two cryo-EM structures: the complete Dark apoptosome at an overall resolution of 4.0 Å and a complex between the Dark apoptosome and the CARD of Dronc at 4.1 Å resolution. The structural findings, together with structure-guided biochemical analyses, allow delineation of the molecular mechanisms for Dronc activation. Apoptosis is executed by a cascade of caspase activation. The autocatalytic activation of an initiator caspase, exemplified by caspase-9 in mammals or its ortholog, Dronc, in fruit flies, is facilitated by a multimeric adaptor complex known as the apoptosome. The underlying mechanism by which caspase-9 or Dronc is activated by the apoptosome remains unknown. Here we report the electron cryomicroscopic (cryo-EM) structure of the intact apoptosome from Drosophila melanogaster at 4.0 Å resolution. Analysis of the Drosophila apoptosome, which comprises 16 molecules of the Dark protein (Apaf-1 ortholog), reveals molecular determinants that support the assembly of the 2.5-MDa complex. In the absence of dATP or ATP, Dronc zymogen potently induces formation of the Dark apoptosome, within which Dronc is efficiently activated. At 4.1 Å resolution, the cryo-EM structure of the Dark apoptosome bound to the caspase recruitment domain (CARD) of Dronc (Dronc-CARD) reveals two stacked rings of Dronc-CARD that are sandwiched between two octameric rings of the Dark protein. The specific interactions between Dronc-CARD and both the CARD and the WD40 repeats of a nearby Dark protomer are indispensable for Dronc activation. These findings reveal important mechanistic insights into the activation of initiator caspase by the apoptosome.
Collapse
Affiliation(s)
- Yuxuan Pang
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xiao-chen Bai
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Chuangye Yan
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Qi Hao
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Zheqin Chen
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Jia-Wei Wang
- Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Sjors H W Scheres
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Yigong Shi
- Ministry of Education Protein Science Laboratory, Center for Structural Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China;
| |
Collapse
|
47
|
Zamaraev AV, Kopeina GS, Zhivotovsky B, Lavrik IN. Cell death controlling complexes and their potential therapeutic role. Cell Mol Life Sci 2015; 72:505-517. [PMID: 25323133 PMCID: PMC11113151 DOI: 10.1007/s00018-014-1757-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/18/2014] [Accepted: 10/09/2014] [Indexed: 12/26/2022]
Abstract
Programmed cell death plays a central role in the regulation of homeostasis and development of multicellular organisms. Deregulation of programmed cell death is connected to a number of disorders, including cancer and autoimmune diseases. Initiation of cell death occurs in the multiprotein complexes or high molecular weight platforms. Composition, structure, and molecular interactions within these platforms influence the cellular decision toward life or death and, therefore, define the induction of a particular cell death program. Here, we discuss in detail the key cell-death complexes-including DISC, complex II, and TNFRI complex I/II, and the necrosome, RIPoptosome, apoptosome, and PIDDosome-that control apoptosis or necroptosis pathways as well as their regulation. The possibility of their pharmacological targeting leading to the development of new strategies of interference with cell death programs via control of the high molecular weight platforms will be discussed.
Collapse
Affiliation(s)
- Alexey V Zamaraev
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991, Moscow, Russia
| | - Gelina S Kopeina
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991, Moscow, Russia
| | - Boris Zhivotovsky
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991, Moscow, Russia.
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden.
| | - Inna N Lavrik
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991, Moscow, Russia
- Department of Translational Inflammation, Institute of Experimental Internal Medicine, Otto von Guericke University, Magdeburg, Germany
| |
Collapse
|
48
|
Lu A, Wu H. Structural mechanisms of inflammasome assembly. FEBS J 2014; 282:435-44. [PMID: 25354325 DOI: 10.1111/febs.13133] [Citation(s) in RCA: 159] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 10/14/2014] [Accepted: 10/24/2014] [Indexed: 01/20/2023]
Abstract
Inflammasomes are supramolecular signaling complexes that activate a subset of caspases known as the inflammatory caspases, an example of which is caspase 1. Upon stimulation by microbial and damage-associated signals, inflammasomes assemble to elicit the first line of host defense via the proteolytic maturation of cytokines interleukin-1β and interleukin-18, and by induction of pyroptotic cell death. Inflammasome assembly requires activation of an upstream sensor, a downstream effector and, in most cases, an adaptor molecule such as apoptosis-associate speck-like protein containing a caspase recruitment domain (ASC). Depending on whether ASC is required, inflammasomes can be categorized into ASC-dependent and ASC-independent inflammasomes. Here, we review current understandings of the structures of inflammasomes, as probed using traditional structural methods, as well as biochemical, biophysical and single-molecule methods. The key structural scaffold for inflammasome assembly is composed of filaments of Pyrin domains and caspase recruitment domains (CARD) in the sensor, adaptor and effector components. Nucleated polymerization appears to govern the ordered assembly process from activation of a Pyrin domain-containing sensor such as AIM2 by dsDNA or NLRP3 by extracellular particulates, to recruitment of the Pyrin domain and CARD-containing adaptor ASC, and finally to activation of CARD-containing caspase 1. The underlying filamentous architecture of inflammasomes and the cooperativity in the assembly may explain the 'all-or-none' response in inflammasome activation. Inflammasomes are tightly regulated by a number of cytosolic inhibitors, which may change the morphology and assembly kinetics of inflammasomes. Biochemical and cellular studies suggest that Pyrin domain and CARD filaments possess prion-like properties in propagating inflammasome activation within and between cells.
Collapse
Affiliation(s)
- Alvin Lu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Cambridge, MA, USA; Chemical Biology PhD Program, Harvard University, Cambridge, MA, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | | |
Collapse
|
49
|
Molecular determinants of caspase-9 activation by the Apaf-1 apoptosome. Proc Natl Acad Sci U S A 2014; 111:16254-61. [PMID: 25313070 DOI: 10.1073/pnas.1418000111] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Autocatalytic activation of an initiator caspase triggers the onset of apoptosis. In dying cells, caspase-9 activation is mediated by a multimeric adaptor complex known as the Apaf-1 apoptosome. The molecular mechanism by which caspase-9 is activated by the Apaf-1 apoptosome remains largely unknown. Here we demonstrate that the previously reported 1:1 interaction between Apaf-1 caspase recruitment domain (CARD) and caspase-9 CARD is insufficient for the activation of caspase-9. Rather, formation of a multimeric CARD:CARD assembly between Apaf-1 and caspase-9, which requires three types of distinct interfaces, underlies caspase-9 activation. Importantly, an additional surface area on the multimeric CARD assembly is essential for caspase-9 activation. Together, these findings reveal mechanistic insights into the activation of caspase-9 by the Apaf-1 apoptosome and support the induced conformation model for initiator caspase activation by adaptor complexes.
Collapse
|
50
|
Würstle ML, Rehm M. A systems biology analysis of apoptosome formation and apoptosis execution supports allosteric procaspase-9 activation. J Biol Chem 2014; 289:26277-26289. [PMID: 25107908 DOI: 10.1074/jbc.m114.590034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protease caspase-9 is activated on the apoptosome, a multiprotein signal transduction platform that assembles in response to mitochondria-dependent apoptosis initiation. Despite extensive molecular research, the assembly of the holo-apoptosome and the process of caspase-9 activation remain incompletely understood. Here, we therefore integrated quantitative data on the molecular interactions and proteolytic processes during apoptosome formation and apoptosis execution and conducted mathematical simulations to investigate the resulting biochemical signaling, quantitatively and kinetically. Interestingly, when implementing the homodimerization of procaspase-9 as a prerequisite for activation, the calculated kinetics of apoptosis execution and the efficacy of caspase-3 activation failed to replicate experimental data. In contrast, assuming a scenario in which procaspase-9 is activated allosterically upon binding to the apoptosome backbone, the mathematical simulations quantitatively and kinetically reproduced all experimental data. These data included a XIAP threshold concentration at which apoptosis execution is suppressed in HeLa cervical cancer cells, half-times of procaspase-9 processing, as well as the molecular timer function of the apoptosome. Our study therefore provides novel mechanistic insight into apoptosome-dependent apoptosis execution and suggests that caspase-9 is activated allosterically by binding to the apoptosome backbone. Our findings challenge the currently prevailing dogma that all initiator procaspases require homodimerization for activation.
Collapse
Affiliation(s)
- Maximilian L Würstle
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland; Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Markus Rehm
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland; Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
| |
Collapse
|