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Sullivan PG, Fiskum G. Editorial: Mitochondria and neurological diseases. Exp Neurol 2020; 334:113467. [PMID: 32980617 DOI: 10.1016/j.expneurol.2020.113467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Patrick G Sullivan
- Spinal Cord and Brain Injury Research Center, Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA.
| | - Gary Fiskum
- Department of Anesthesiology, Center for Shock, Trauma, Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Teng X, Yau E, Sing C, Hardwick JM. Whi2 signals low leucine availability to halt yeast growth and cell death. FEMS Yeast Res 2018; 18:5083179. [PMID: 30165592 PMCID: PMC6149368 DOI: 10.1093/femsyr/foy095] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 08/26/2018] [Indexed: 12/16/2022] Open
Abstract
Cells are exquisitely tuned to environmental ques. Amino acid availability is rapidly sensed, allowing cells to adjust molecular processes and implement short or long-term metabolic shifts accordingly. How levels of most individual amino acids may be sensed and subsequently signaled to inform cells of their nutrient status is largely unknown. We made the unexpected observation that small changes in the levels of specific amino acids can have a profound effect on yeast cell growth, leading to the identification of yeast Whi2 as a negative regulator of cell growth in low amino acids. Although Whi2 was originally thought to be fungi-specific, Whi2 appears to share a conserved structural domain found in a family of 25 largely uncharacterized human genes encoding the KCTD (potassium channel tetramerization domain) protein family. Insights gained from yeast Whi2 are likely to be revealing about human KCTDs, many of which have been implicated or demonstrated to cause disease when mutated. Here we report new evidence that Whi2 responds to specific amino acids in the medium, particularly low leucine levels. We also discuss the known pathways of amino acid signaling and potential points of regulation by Whi2 in nutrient signaling in yeast and mammals.
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Affiliation(s)
- Xinchen Teng
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205-2103, USA
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, 215123 Suzhou, Jiangsu Province, People's Republic of China
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2103, USA
| | - Eric Yau
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205-2103, USA
| | - Cierra Sing
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205-2103, USA
| | - J Marie Hardwick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205-2103, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2103, USA
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Luo J, Qin J, Fu Y, Zhang S, Zhang X, Yang M. 6'-Hydroxy Justicidin B Triggers a Critical Imbalance in Ca 2+ Homeostasis and Mitochondrion-Dependent Cell Death in Human Leukemia K562 Cells. Front Pharmacol 2018; 9:601. [PMID: 29950991 PMCID: PMC6008565 DOI: 10.3389/fphar.2018.00601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 05/18/2018] [Indexed: 12/13/2022] Open
Abstract
Justicia procumbens (J. procumbens) is a traditional Chinese herbal medicine which was used for the treatment of fever, pain, and cancer. A compound 6'-hydroxy justicidin B (HJB) isolated from J. procumbens exhibits promising biological properties. However, the mechanism of action and the in vivo behavior of HJB remain to be elucidated. In this study, we investigated the mechanism of action of HJB on human leukemia K562 cells and its pharmacokinetic properties in rats. The results demonstrated that HJB significantly inhibited the proliferation of K562 cells and promoted apoptosis. Besides, HJB resulted in decreased mitochondrial membrane potential deltaPSIm, increased the level of the calcium homeostasis regulator protein TRPC6 and cytosolic calcium. The activity of caspase-8, caspase-9 and the expression of p53 were significantly increased after treatment with HJB. Additionally, HJB has rapid absorption rate and relative long elimination t1/2, indicating a longer residence time in vivo. The results indicate that HJB inhibited the proliferation of K562 cells and induced apoptosis by affecting the function of mitochondria and calcium homeostasis to activate the p53 signaling pathway. The pharmacokinetic study of HJB suggested it is absorbed well and has moderate metabolism in vivo. These results present HJB as a potential novel alternative to standard human leukemia therapies.
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Affiliation(s)
- Jiaoyang Luo
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiaan Qin
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yanwei Fu
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shanshan Zhang
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xingguo Zhang
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Meihua Yang
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Hatok J, Racay P. Bcl-2 family proteins: master regulators of cell survival. Biomol Concepts 2017; 7:259-70. [PMID: 27505095 DOI: 10.1515/bmc-2016-0015] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/06/2016] [Indexed: 02/06/2023] Open
Abstract
The most prominent function of proteins of the Bcl-2 family is regulation of the initiation of intrinsic (mitochondrial) pathways of apoptosis. However, recent research has revealed that in addition to regulation of mitochondrial apoptosis, proteins of the Bcl-2 family play important roles in regulating other cellular pathways with a strong impact on cell survival like autophagy, endoplasmic reticulum (ER) stress response, intracellular calcium dynamics, cell cycle progression, mitochondrial dynamics and energy metabolism. This review summarizes the recent knowledge about functions of Bcl-2 family proteins that are related to cell survival.
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Clavier A, Rincheval-Arnold A, Colin J, Mignotte B, Guénal I. Apoptosis in Drosophila: which role for mitochondria? Apoptosis 2015; 21:239-51. [DOI: 10.1007/s10495-015-1209-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Dimorphic ovary differentiation in honeybee (Apis mellifera) larvae involves caste-specific expression of homologs of ark and buffy cell death genes. PLoS One 2014; 9:e98088. [PMID: 24844304 PMCID: PMC4028266 DOI: 10.1371/journal.pone.0098088] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 04/28/2014] [Indexed: 01/25/2023] Open
Abstract
The establishment of the number of repeated structural units, the ovarioles, in the ovaries is one of the critical events that shape caste polyphenism in social insects. In early postembryonic development, honeybee (Apis mellifera) larvae have a pair of ovaries, each one consisting of almost two hundred ovariole primordia. While practically all these ovarioles continue developing in queen-destined larvae, they undergo massive programmed cell death (PCD) in worker-destined larvae. So as to gain insight into the molecular basis of this fundamental process in caste differentiation we used quantitative PCR (qPCR) and fluorescent in situ hybridization (FISH) to investigate the expression of the Amark and Ambuffy genes in the ovaries of the two honeybee castes throughout the fifth larval instar. These are the homologs of ark and buffy Drosophila melanogaster genes, respectively, involved in activating and inhibiting PCD. Caste-specific expression patterns were found during this time-window defining ovariole number. Amark transcript levels were increased when ovariole resorption was intensified in workers, but remained at low levels in queen ovaries. The transcripts were mainly localized at the apical end of all the worker ovarioles, but appeared in only a few queen ovarioles, thus strongly suggesting a function in mediating massive ovariolar cell death in worker larvae. Ambuffy was mainly expressed in the peritoneal sheath cells covering each ovariole. The levels of Ambuffy transcripts increased earlier in the developing ovaries of queens than in workers. Consistent with a protective role against cell death, Ambuffy transcripts were localized in practically all queen ovarioles, but only in few worker ovarioles. The results are indicative of a functional relationship between the expression of evolutionary conserved cell death genes and the morphological events leading to caste-specific ovary differentiation in a social insect.
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Sacchetti S, Alavian KN, Lazrove E, Jonas EA. F1FO ATPase vesicle preparation and technique for performing patch clamp recordings of submitochondrial vesicle membranes. J Vis Exp 2013:e4394. [PMID: 23685483 DOI: 10.3791/4394] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Mitochondria are involved in many important cellular functions including metabolism, survival(1), development and, calcium signaling(2). Two of the most important mitochondrial functions are related to the efficient production of ATP, the energy currency of the cell, by oxidative phosphorylation, and the mediation of signals for programmed cell death(3). The enzyme primarily responsible for the production of ATP is the F1FO-ATP synthase, also called ATP synthase(4-5). In recent years, the role of mitochondria in apoptotic and necrotic cell death has received considerable attention. In apoptotic cell death, BCL-2 family proteins such as Bax enter the mitochondrial outer membrane, oligomerize and permeabilize the outer membrane, releasing pro-apoptotic factors into the cytosol(6). In classic necrotic cell death, such as that produced by ischemia or excitotoxicity in neurons, a large, poorly regulated increase in matrix calcium contributes to the opening of an inner membrane pore, the mitochondrial permeability transition pore or mPTP. This depolarizes the inner membrane and causes osmotic shifts, contributing to outer membrane rupture, release of pro-apoptotic factors, and metabolic dysfunction. Many proteins including Bcl-xL(7) interact with F1FO ATP synthase, modulating its function. Bcl-xL interacts directly with the beta subunit of F1FO ATP synthase, and this interaction decreases a leak conductance within the F1FOATPasecomplex, increasing the net transport of H+ by F1FO during F1FO ATPase activity(8) and thereby increasing mitochondrial efficiency. To study the activity and modulation of the ATP synthase, we isolated from rodent brain submitochondrial vesicles (SMVs) containing F1FO ATPase. The SMVs retain the structural and functional integrity of the F1FO ATPase as shown in Alavian et al. Here, we describe a method that we have used successfully for the isolation of SMVs from rat brain and we delineate the patch clamp technique to analyze channel activity (ion leak conductance) of the SMVs.
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Abstract
BCL-2 family proteins are the regulators of apoptosis, but also have other functions. This family of interacting partners includes inhibitors and inducers of cell death. Together they regulate and mediate the process by which mitochondria contribute to cell death known as the intrinsic apoptosis pathway. This pathway is required for normal embryonic development and for preventing cancer. However, before apoptosis is induced, BCL-2 proteins have critical roles in normal cell physiology related to neuronal activity, autophagy, calcium handling, mitochondrial dynamics and energetics, and other processes of normal healthy cells. The relative importance of these physiological functions compared to their apoptosis functions in overall organismal physiology is difficult to decipher. Apoptotic and noncanonical functions of these proteins may be intertwined to link cell growth to cell death. Disentanglement of these functions may require delineation of biochemical activities inherent to the characteristic three-dimensional shape shared by distantly related viral and cellular BCL-2 family members.
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Han YH, Kim SZ, Kim SH, Park WH. 2,4-Dinitrophenol induces apoptosis in As4.1 juxtaglomerular cells through rapid depletion of GSH. Cell Biol Int 2013; 32:1536-45. [DOI: 10.1016/j.cellbi.2008.08.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 07/10/2008] [Accepted: 08/19/2008] [Indexed: 12/16/2022]
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He XL, Zhang P, Dong XZ, Yang MH, Chen SL, Bi MG. JR6, a new compound isolated from Justicia procumbens, induces apoptosis in human bladder cancer EJ cells through caspase-dependent pathway. JOURNAL OF ETHNOPHARMACOLOGY 2012; 144:284-292. [PMID: 22985636 DOI: 10.1016/j.jep.2012.09.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 07/24/2012] [Accepted: 09/03/2012] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Numerous efforts have been conducted in searching for effective agents against cancer, in particular from herbal medicines. Justicia procumbens is a traditional herbal remedy which was produced in the south-western and southern provinces of China and Taiwan province used to treat fever, pain, and cancer. Here, we identified a new compound 6'-hydroxy justicidin A (JR6) from Justicia procumbens, which showed obvious anti-cancer effects. MATERIALS AND METHODS The cytotoxicity activity was assayed using MTT and SRB. Intracellular ROS visualization and quantification were acquired by using a laser scanning confocal microscopy. Apoptosis was measured using a propidium iodide (PI) apoptosis detection kit by flow cytometry. Activation of caspases (caspase-3, caspase-8, and caspase-9) was evaluated respectively using GloMax luminescence detector and Caspase-Glo 3,8,9 assay kits. Loss of mitochondrial membrane potential was observed by microscopy using JC-1 dye. Quantitative real-time PCR analysis was employed to detect the expression of protein associated with cell death. RESULTS JR6 remarkably inhibited growth in human bladder cancer EJ cells by decreasing cell proliferation, reduced the SOD activity, increased the content of reactive oxygen species (ROS), and induced apoptosis. Activation of caspase-8, caspase-9, and the subsequent activation of caspase-3 indicated that JR6 may be inducing intrinsic and extrinsic apoptosis pathways. Caspase-3, caspase-8, and caspase-9 inhibition rendered this extract ineffective, thus JR6-induced apoptosis is caspase-dependent. JR6 also disrupted the mitochondrial membrane potential (Δψm) and unregulated the Bax and p53 expressions in EJ cells. CONCLUSION These observations suggest that JR6 induce apoptosis through caspase-dependent pathway in human bladder cancer EJ cells, emphasizing the importance of this traditional medicine and thus presents a potential novel alternative to bladder cancer therapy.
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Affiliation(s)
- Xiao-Li He
- Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 151 Malianwa North Road, Haidian District, Beijing, China
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Monserrate JP, Chen MYY, Brachmann CB. Drosophila larvae lacking the bcl-2 gene, buffy, are sensitive to nutrient stress, maintain increased basal target of rapamycin (Tor) signaling and exhibit characteristics of altered basal energy metabolism. BMC Biol 2012; 10:63. [PMID: 22824239 PMCID: PMC3411425 DOI: 10.1186/1741-7007-10-63] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 07/24/2012] [Indexed: 01/07/2023] Open
Abstract
Background B cell lymphoma 2 (Bcl-2) proteins are the central regulators of apoptosis. The two bcl-2 genes in Drosophila modulate the response to stress-induced cell death, but not developmental cell death. Because null mutants are viable, Drosophila provides an optimum model system to investigate alternate functions of Bcl-2 proteins. In this report, we explore the role of one bcl-2 gene in nutrient stress responses. Results We report that starvation of Drosophila larvae lacking the bcl-2 gene, buffy, decreases survival rate by more than twofold relative to wild-type larvae. The buffy null mutant reacted to starvation with the expected responses such as inhibition of target of rapamycin (Tor) signaling, autophagy initiation and mobilization of stored lipids. However, the autophagic response to starvation initiated faster in larvae lacking buffy and was inhibited by ectopic buffy. We demonstrate that unusually high basal Tor signaling, indicated by more phosphorylated S6K, was detected in the buffy mutant and that removal of a genomic copy of S6K, but not inactivation of Tor by rapamycin, reverted the precocious autophagy phenotype. Instead, Tor inactivation also required loss of a positive nutrient signal to trigger autophagy and loss of both was sufficient to activate autophagy in the buffy mutant even in the presence of enforced phosphoinositide 3-kinase (PI3K) signaling. Prior to starvation, the fed buffy mutant stored less lipid and glycogen, had high lactate levels and maintained a reduced pool of cellular ATP. These observations, together with the inability of buffy mutant larvae to adapt to nutrient restriction, indicate altered energy metabolism in the absence of buffy. Conclusions All animals in their natural habitats are faced with periods of reduced nutrient availability. This study demonstrates that buffy is required for adaptation to both starvation and nutrient restriction. Thus, Buffy is a Bcl-2 protein that plays an important non-apoptotic role to promote survival of the whole organism in a stressful situation.
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12
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Bid protects the mouse hematopoietic system following hydroxyurea-induced replicative stress. Cell Death Differ 2012; 19:1602-12. [PMID: 22522598 DOI: 10.1038/cdd.2012.38] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Hematopoietic stem cells (HSCs) possess long-term self-renewal capacity and multipotent differentiative capacity, to maintain the hematopoietic system. Long-term hematopoietic homeostasis requires effective control of genotoxic damage to maintain HSC function and prevent propagation of deleterious mutations. Here we investigate the role of the BH3-only Bcl-2 family member Bid in the response of murine hematopoietic cells to long-term replicative stress induced by hydroxyurea (HU). The PI3-like serine/threonine kinase, ATR, initiates the DNA damage response (DDR) to replicative stress. The pro-apoptotic Bcl-2 family member, Bid, facilitates this response to replicative stress in hematopoietic cells, but the in vivo role of this DDR function of Bid has not been defined. Surprisingly, we demonstrate that long-term HU treatment expands wild-type myeloid progenitor cells (MPCs) and HSC-enriched Lin(-)Sca1(+)Kit(+) (LSK) cells to maintain bone marrow function as measured by long-term competitive repopulating ability. Bid-/- MPCs demonstrate increased sensitivity to HU and are depleted. Bid-/- LSK cells demonstrate increased mobilization manifest by increased Bromodeoxyuridine (BrdU) incorporation. Bid-/- MPCs and LSK cells are relatively depleted, however, and bone marrow from Bid-/- mice demonstrates decreased long-term competitive repopulating ability in both primary and secondary transplants. We thus describe a survival function of Bid in hematopoiesis in the setting of chronic replicative stress.
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Vogel S, Raulf N, Bregenhorn S, Biniossek ML, Maurer U, Czabotar P, Borner C. Cytosolic Bax: does it require binding proteins to keep its pro-apoptotic activity in check? J Biol Chem 2012; 287:9112-27. [PMID: 22277657 DOI: 10.1074/jbc.m111.248906] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bax is kept inactive in the cytosol by refolding its C-terminal transmembrane domain into the hydrophobic binding pocket. Although energetic calculations predicted this conformation to be stable, numerous Bax binding proteins were reported and suggested to further stabilize inactive Bax. Unfortunately, most of them have not been validated in a physiological context on the endogenous level. Here we use gel filtration analysis of the cytosol of primary and established cells to show that endogenous, inactive Bax runs 20-30 kDa higher than recombinant Bax, suggesting Bax dimerization or the binding of a small protein. Dimerization was excluded by a lack of interaction of differentially tagged Bax proteins and by comparing the sizes of dimerized recombinant Bax with cytosolic Bax on blue native gels. Surprisingly, when analyzing cytosolic Bax complexes by high sensitivity mass spectrometry after anti-Bax immunoprecipitation or consecutive purification by gel filtration and blue native gel electrophoresis, we detected only one protein, called p23 hsp90 co-chaperone, which consistently and specifically co-purified with Bax. However, this protein could not be validated as a crucial inhibitory Bax binding partner as its over- or underexpression did not show any apoptosis defects. By contrast, cytosolic Bax exhibits a slight molecular mass shift on SDS-PAGE as compared with recombinant Bax, which suggests a posttranslational modification and/or a structural difference between the two proteins. We propose that in most healthy cells, cytosolic endogenous Bax is a monomeric protein that does not necessarily need a binding partner to keep its pro-apoptotic activity in check.
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Affiliation(s)
- Sandra Vogel
- Institute of Molecular Medicine and Cell Research, Center for Biochemistry and Molecular Cell Research, Albert Ludwigs University, Freiburg, Germany
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Verma G, Datta M. The critical role of JNK in the ER-mitochondrial crosstalk during apoptotic cell death. J Cell Physiol 2012; 227:1791-5. [DOI: 10.1002/jcp.22903] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Hartman AL. Neuroprotection in metabolism-based therapy. Epilepsy Res 2011; 100:286-94. [PMID: 21872441 DOI: 10.1016/j.eplepsyres.2011.04.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Revised: 04/20/2011] [Accepted: 04/25/2011] [Indexed: 12/21/2022]
Abstract
Metabolism-based therapy has been used successfully in the treatment of seizures but study of its use in other neurodegenerative disorders is growing. Data demonstrating the use of different forms of metabolism-based therapy in human trials of Alzheimer disease and Parkinson disease are discussed. Animal and in vitro studies have shed light on metabolism-based therapy's mechanisms in these diseases, as well as ALS, aging, ischemia, trauma and mitochondrial cytopathies. Additional insights may be obtained by considering the role of metabolism-based therapy in cell disability and death (specifically apoptosis, excitotoxicity, and autophagy).
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Affiliation(s)
- Adam L Hartman
- Johns Hopkins University, Neurology, 600 N. Wolfe St., Meyer 2-147, Baltimore, MD 21287, USA.
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16
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BID binds to replication protein A and stimulates ATR function following replicative stress. Mol Cell Biol 2011; 31:4298-309. [PMID: 21859891 DOI: 10.1128/mcb.05737-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Proapoptotic BH3-interacting death domain agonist (BID) regulates apoptosis and the DNA damage response. Following replicative stress, BID associates with proteins of the DNA damage sensor complex, including replication protein A (RPA), ataxia telangiectasia and Rad3 related (ATR), and ATR-interacting protein (ATRIP), and facilitates an efficient DNA damage response. We have found that BID stimulates the association of RPA with components of the DNA damage sensor complex through interaction with the basic cleft of the N-terminal domain of the RPA70 subunit. Disruption of the BID-RPA interaction impairs the association of ATR-ATRIP with chromatin as well as ATR function, as measured by CHK1 activation and recovery of DNA replication following hydroxyurea (HU). We further demonstrate that the association of BID with RPA stimulates the association of ATR-ATRIP to the DNA damage sensor complex. We propose a model in which BID associates with RPA and stimulates the recruitment and/or stabilization of ATR-ATRIP to the DNA damage sensor complex.
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Duncan R, Gannavaram S, Dey R, Debrabant A, Lakhal-Naouar I, Nakhasi HL. Identification and characterization of genes involved in leishmania pathogenesis: the potential for drug target selection. Mol Biol Int 2011; 2011:428486. [PMID: 22091403 PMCID: PMC3200065 DOI: 10.4061/2011/428486] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/26/2011] [Accepted: 04/28/2011] [Indexed: 12/14/2022] Open
Abstract
Identifying and characterizing Leishmania donovani genes and the proteins they encode for their role in pathogenesis can reveal the value of this approach for finding new drug targets. Effective drug targets are likely to be proteins differentially expressed or required in the amastigote life cycle stage found in the patient. Several examples and their potential for chemotherapeutic disruption are presented. A pathway nearly ubiquitous in living cells targeted by anticancer drugs, the ubiquitin system, is examined. New findings in ubiquitin and ubiquitin-like modifiers in Leishmania show how disruption of those pathways could point to additional drug targets. The programmed cell death pathway, now recognized among protozoan parasites, is reviewed for some of its components and evidence that suggests they could be targeted for antiparasitic drug therapy. Finally, the endoplasmic reticulum quality control system is involved in secretion of many virulence factors. How disruptions in this pathway reduce virulence as evidence for potential drug targets is presented.
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Affiliation(s)
- Robert Duncan
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, FDA, Bethesda, MD 20852, USA
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18
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Chen Z, Zhu Y, Ren Y, Tong Y, Hua X, Zhu F, Huang L, Liu Y, Luo Y, Lu W, Zhao P, Qi Z. Hepatitis C virus protects human B lymphocytes from Fas-mediated apoptosis via E2-CD81 engagement. PLoS One 2011; 6:e18933. [PMID: 21526201 PMCID: PMC3079738 DOI: 10.1371/journal.pone.0018933] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Accepted: 03/13/2011] [Indexed: 12/13/2022] Open
Abstract
HCV infection is often associated with B-cell regulatory control disturbance and delayed appearance of neutralizing antibodies. CD81 is a cellular receptor for HCV and can bind to HCV envelope protein 2 (E2). CD81 also participates to form a B cell costimulatory complex. To investigate whether HCV influences B cell activation and immune function through E2 -CD81 engagement, here, human Burkitt's lymphoma cell line Raji cells and primary human B lymphocytes (PHB) were treated with HCV E2 protein and cell culture produced HCV particles (HCVcc), and then the related cell phenotypes were assayed. The results showed that both E2 and HCVcc triggered phosphorylation of IκBα, enhanced the expression of anti-apoptosis Bcl-2 family proteins, and protected Raji cells and PHB cells from Fas-mediated death. In addition, both E2 protein and HCVcc increased the expression of costimulatory molecules CD80, CD86 and CD81 itself, and decreased the expression of complement receptor CD21. The effects were dependent on E2-CD81 interaction on the cell surface, since CD81-silenced Raji cells did not respond to both treatments; and an E2 mutant that lose the CD81 binding activity, could not trigger the responses of both Raji cells and PHB cells. The effects were not associated with HCV replication in cells, for HCV pseudoparticle (HCVpp) and HCVcc failed to infect Raji cells. Hence, E2-CD81 engagement may contribute to HCV-associated B cell lymphoproliferative disorders and insufficient neutralizing antibody production.
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Affiliation(s)
- Zhihui Chen
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
- Department of Infectious Diseases, Affiliated Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Yongzhe Zhu
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Yanli Ren
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Yimin Tong
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Xian Hua
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Fenghui Zhu
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Libin Huang
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Yuan Liu
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Yuan Luo
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
| | - Wei Lu
- Department of Epidemiology, Second Military Medical University, Shanghai, China
| | - Ping Zhao
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
- * E-mail: (ZQ); (PZ)
| | - Zhongtian Qi
- Department of Microbiology, Shanghai Key Laboratory of Medical Biodefense, Second Military Medical University, Shanghai, China
- * E-mail: (ZQ); (PZ)
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Ofengeim D, Miyawaki T, Suzanne zukin R. Molecular and Cellular Mechanisms of Ischemia-Induced Neuronal Death. Stroke 2011. [DOI: 10.1016/b978-1-4160-5478-8.10006-5] [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]
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Shamas-Din A, Brahmbhatt H, Leber B, Andrews DW. BH3-only proteins: Orchestrators of apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:508-20. [PMID: 21146563 DOI: 10.1016/j.bbamcr.2010.11.024] [Citation(s) in RCA: 246] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/29/2010] [Accepted: 11/30/2010] [Indexed: 12/13/2022]
Abstract
The BH3-only proteins of Bcl-2 family are essential initiators of apoptosis that propagate extrinsic and intrinsic cell death signals. The interaction of BH3-only proteins with other Bcl-2 family members is critical for understanding the core machinery that controls commitment to apoptosis by permeabilizing the mitochondrial outer membrane. BH3-only proteins promote apoptosis by both directly activating Bax and Bak and by suppressing the anti-apoptotic proteins at the mitochondria and the endoplasmic reticulum. To prevent constitutive cell death, BH3-only proteins are regulated by a variety of mechanisms including transcription and post-translational modifications that govern specific protein-protein interactions. Furthermore, BH3-only proteins also control the initiation of autophagy, another important pathway regulating cell survival and death. Emerging evidence indicates that the interaction of BH3-only proteins with membranes regulates binding to other Bcl-2 family members, thereby specifying function. Due to the important role of BH3-only proteins in the regulation of cell death, several promising BH3-mimetic drugs that are active in pre-clinical models are currently being tested as anti-cancer agents. This article is part of a Special Issue entitled Mitochondria: the deadly organelle.
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Affiliation(s)
- Aisha Shamas-Din
- Department of Biochemistry and Biomedical Sciences and McMaster University, Hamilton, Ontario, Canada
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Liu Y, Bertram CC, Shi Q, Zinkel SS. Proapoptotic Bid mediates the Atr-directed DNA damage response to replicative stress. Cell Death Differ 2010; 18:841-52. [PMID: 21113148 DOI: 10.1038/cdd.2010.151] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Proapoptotic BH3 interacting domain death agonist (Bid), a BH3-only Bcl-2 family member, is situated at the interface between the DNA damage response and apoptosis, with roles in death receptor-induced apoptosis as well as cell cycle checkpoints following DNA damage.(1, 2, 3) In this study, we demonstrate that Bid functions at the level of the sensor complex in the Atm and Rad3-related (Atr)-directed DNA damage response. Bid is found with replication protein A (RPA) in nuclear foci and associates with the Atr/Atr-interacting protein (Atrip)/RPA complex following replicative stress. Furthermore, Bid-deficient cells show an impaired response to replicative stress manifest by reduced accumulation of Atr and Atrip on chromatin and at DNA damage foci, reduced recovery of DNA synthesis following replicative stress, and decreased checkpoint kinase 1 activation and RPA phosphorylation. These results establish a direct role for the BH3-only Bcl-2 family member, Bid, acting at the level of the damage sensor complex to amplify the Atr-directed cellular response to replicative DNA damage.
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Affiliation(s)
- Y Liu
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Rinaldi T, Dallabona C, Ferrero I, Frontali L, Bolotin-Fukuhara M. Mitochondrial diseases and the role of the yeast models. FEMS Yeast Res 2010; 10:1006-22. [PMID: 20946356 DOI: 10.1111/j.1567-1364.2010.00685.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Nowadays, mitochondrial diseases are recognized and studied with much attention and they cannot be considered anymore as 'rare diseases'. Yeast has been an instrumental organism to understand the genetic and molecular aspects of the many roles of mitochondria within the cells. Thanks to the general conservation of mitochondrial genes and pathways between human and yeast, it can also be used to model some diseases. In this review, we focus on the most recent topics, exemplifying those for which yeast models have been especially valuable.
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Affiliation(s)
- Teresa Rinaldi
- Department of Cell and Developmental Biology, Pasteur Institute-Cenci Bolognetti Foundation, Sapienza University of Rome, Rome, Italy
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Wu JN, Nguyen N, Aghazarian M, Tan Y, Sevrioukov EA, Mabuchi M, Tang W, Monserrate JP, White K, Brachmann CB. grim promotes programmed cell death of Drosophila microchaete glial cells. Mech Dev 2010; 127:407-17. [PMID: 20558283 DOI: 10.1016/j.mod.2010.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 05/28/2010] [Accepted: 06/05/2010] [Indexed: 12/01/2022]
Abstract
The Inhibitor of apoptosis (IAP) antagonists Reaper (Rpr), Grim and Hid are central regulators of developmental apoptosis in Drosophila. Ectopic expression of each is sufficient to trigger apoptosis, and hid and rpr have been shown to be important for programmed cell death (PCD). To investigate the role for grim in PCD, a grim null mutant was generated. grim was not a key proapoptotic gene for embryonic PCD, confirming that grim cooperates with rpr and hid in embryogenesis. In contrast, PCD of glial cells in the microchaete lineage required grim, identifying a death process dependent upon endogenous grim. Grim associates with mitochondria and has been shown to activate a mitochondrial death pathway distinct from IAP antagonization; therefore, the Drosophila bcl-2 genes buffy and debcl were investigated for genetic interaction with grim. Loss of buffy led to microchaete glial cell survival and suppressed death in the eye induced by ectopic Grim. This is the first example of a developmental PCD process influenced by buffy, and places buffy in a proapoptotic role. PCD of microchaete glial cells represents an exceptional opportunity to study the mitochondrial proapoptotic process induced by Grim.
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Affiliation(s)
- Julie N Wu
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697-2300, USA
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Anagnostou VK, Lowery FJ, Zolota V, Tzelepi V, Gopinath A, Liceaga C, Panagopoulos N, Frangia K, Tanoue L, Boffa D, Gettinger S, Detterbeck F, Homer RJ, Dougenis D, Rimm DL, Syrigos KN. High expression of BCL-2 predicts favorable outcome in non-small cell lung cancer patients with non squamous histology. BMC Cancer 2010; 10:186. [PMID: 20459695 PMCID: PMC2875218 DOI: 10.1186/1471-2407-10-186] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 05/09/2010] [Indexed: 01/16/2023] Open
Abstract
Background Bcl-2 promotes cell survival by inhibiting adapters needed for the activation and cleavage of caspases thus blocking the proteolytic cascade that ultimately dismantles the cell. Bcl-2 has been investigated as a prognostic factor in non small cell lung cancer (NSCLC) patients with conflicting results. Methods Here, we quantitatively assessed Bcl-2 expression in two large and independent cohorts to investigate the impact of Bcl-2 on survival. AQUA®, a fluorescent-based method for analysis of in situ protein expression, was used to measure Bcl-2 protein levels and classify tumors by Bcl-2 expression in a cohort of 180 NSCLC patients. An independent cohort of 354 NSCLC patients was used to validate Bcl-2 classification and evaluate outcome. Results Fifty % and 52% of the cases were classified as high expressers in training and validation cohorts respectively. Squamous cell carcinomas were more likely to be high expressers compared to adenocarcinomas (63% vs. 45%, p = 0.002); Bcl-2 was not associated with other clinical or pathological characteristics. Survival analysis showed that patients with high BCL-2 expression had a longer median survival compared to low expressers (22 vs. 17.5 months, log rank p = 0.014) especially in the subset of non-squamous tumors (25 vs. 13.8 months, log rank p = 0.04). Multivariate analysis revealed an independent lower risk for all patients with Bcl-2 expressing tumors (HR = 0.53, 95% CI 0.37-0.75, p = 0.0003) and for patients with non-squamous tumors (HR = 0.5, 95% CI 0.31-0.81, p = 0.005). Conclusions Bcl-2 expression defines a subgroup of patients with a favorable outcome and may be useful for prognostic stratification of NSCLC patients.
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Affiliation(s)
- Valsamo K Anagnostou
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
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Lavoie JN, Landry MC, Faure RL, Champagne C. Src-family kinase signaling, actin-mediated membrane trafficking and organellar dynamics in the control of cell fate: lessons to be learned from the adenovirus E4orf4 death factor. Cell Signal 2010; 22:1604-14. [PMID: 20417707 DOI: 10.1016/j.cellsig.2010.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 04/15/2010] [Indexed: 12/15/2022]
Abstract
Evidence has accumulated that there are different modes of regulated cell death, which share overlapping signaling pathways. Cytoskeletal-dependent inter-organellar communication as a result of protein and lipid trafficking in and out of organelles has emerged as a common, key issue in the regulation of cell death modalities. The movement of proteins and lipids between cell compartments is believed to relay death signals in part through modifications of organelles dynamics. Little is known, however, regarding how trafficking is integrated within stress signaling pathways directing organelle-specific remodeling events. In this review, we discuss emerging evidence supporting a role for regulated changes in actin dynamics and intracellular membrane flow. Based on recent findings using the adenovirus E4orf4 death factor as a probing tool to tackle the mechanistic underpinnings that control alternative modes of cell death, we propose the existence of multifunctional platforms at the endosome-Golgi interface regulated by SFK-signaling. These endosomal platforms could be mobilized during cell activation processes to reorganize cellular membranes and promote inter-organelle signaling.
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Affiliation(s)
- Josée N Lavoie
- Centre de Recherche en Cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec, CRCHUQ, Québec, Canada.
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Danial NN, Gimenez-Cassina A, Tondera D. Homeostatic functions of BCL-2 proteins beyond apoptosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 687:1-32. [PMID: 20919635 DOI: 10.1007/978-1-4419-6706-0_1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Since its introduction in 1930 by physiologist Walter Bradford Cannon, the concept of homeostasis remains the cardinal tenet of biologic regulation. Cells have evolved a highly integrated network of control mechanisms, including positive and negative feedback loops, to safeguard homeostasis in face of a wide range of stimuli. Such control mechanisms ultimately orchestrate cell death, division and repair in a manner concordant with cellular energy and ionic balance to achieve proper biologic fitness. The interdependence of these homeostatic pathways is also evidenced by shared control points that decode intra- and extracellular cues into defined effector responses. As critical control points of the intrinsic apoptotic pathway, the BCL-2 family of cell death regulators plays an important role in cellular homeostasis. The different anti- and pro-apoptotic members of this family form a highly selective network of functional interactions that ultimately governs the permeabilization of the mitochondrial outer membrane and subsequent release of apoptogenic factors such as cytochrome c. The advent of loss- and gain-of-function genetic models for the various BCL-2 family proteins has not only provided important insights into apoptosis mechanisms but also uncovered unanticipated roles for these proteins in other physiologic pathways beyond apoptosis (Fig. 1). Here, we turn our attention to these alternative cellular functions for BCL-2 proteins. We begin with a brief introduction of the cast of characters originally known for their capacity to regulate apoptosis and continue to highlight recent advances that have shaped and reshaped our views on their physiologic relevance in integration of apoptosis with other homeostatic pathways.
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Affiliation(s)
- Nika N Danial
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA.
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Han YH, Moon HJ, You BR, Kim SZ, Kim SH, Park WH. Effects of carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone on the growth inhibition in human pulmonary adenocarcinoma Calu-6 cells. Toxicology 2009; 265:101-7. [PMID: 19819288 DOI: 10.1016/j.tox.2009.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 10/01/2009] [Accepted: 10/01/2009] [Indexed: 12/20/2022]
Abstract
Carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) is an uncoupler of mitochondrial oxidative phosphorylation in eukaryotic cells. Here, we evaluated the in vitro effects of FCCP on the growth of Calu-6 lung cancer cells. FCCP inhibited the growth of Calu-6 cells with an IC(50) of approximately 6.64+/-1.84 microM at 72 h, as shown by MTT. DNA flow cytometric analysis indicated that FCCP induced G1 phase arrest below 20 microM of FCCP. Treatment with FCCP decreased the level of CDKs and cyclines in relation to G1 phase. In addition, FCCP not only increased the p27 level but also enhanced its binding with CDK4, which was associated with hypophosphorylation of Rb protein. While transfection of p27 siRNA inhibited G1 phase arrest in FCCP-treated cells, it did not enhance Rb phosphorylation. FCCP also efficiently induced apoptosis. The apoptotic process was accompanied with an increase in sub-G1 cells, annexin V staining cells, mitochondria membrane potential (MMP) loss and cleavage of PARP protein. All of the caspase inhibitors (caspase-3, -8, -9 and pan-caspase inhibitor) markedly rescued the Calu-6 cells from FCCP-induced cell death. However, knock down of p27 protein intensified FCCP-induced cell death. Moreover, FCCP induced the depletion of GSH content in Calu-6 cells, which was prevented by all of the caspase inhibitors. In summary, our results demonstrated that FCCP inhibits the growth of Calu-6 cells in vitro. The growth inhibitory effect of FCCP might be mediated by cell cycle arrest and apoptosis via decrease of CDKs and caspase activation, respectively. These findings now provide a better elucidation of the mechanisms involved in FCCP-induced growth inhibition in lung cancer.
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Affiliation(s)
- Yong Hwan Han
- Department of Physiology, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju 561-180, Republic of Korea
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Abstract
OBJECTIVES To study the molecular mechanism of arsenic trioxide-induced cell death on cerulein-stimulated AR42J cells. METHODS AR42J cells were incubated for 24 hours, and cerulein (10 nmol/L) and different concentrations of arsenic trioxide were added for another 24 hours. The cells were collected and analyzed for apoptosis and oncosis by using rhodamine 123 and propidium iodide staining, and the changes in the genes that related to cell death were detected by a gene chip. RESULTS After cerulein stimulation, apoptosis was significantly increased in the AR42J cells. The addition of arsenic trioxide increased the number of apoptotic cells, and the apoptotic index reached its peak in the 1-micromol/L group. Regarding oncosis, low concentrations of arsenic trioxide (0.5, 1, 2, and 4 micromol/L) reduced the development of oncosis, and in the 2-micromol/L group, it was most significant, whereas high concentration of arsenic trioxide (8 micromol/L) promoted the development of oncosis. A total of 96 genes related to apoptosis were detected, and 36 genes were differentially expressed. CONCLUSIONS Appropriate concentrations of arsenic trioxide can induce apoptosis in AR42J cells that were induced by cerulein and lead to changes in the expressions of certain genes.
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Abstract
The BH3-only pro-apoptotic proteins are upstream sensors of cellular damage that selectively respond to specific, proximal death and survival signals. Genetic models and biochemical studies indicate that these molecules are latent killers until activated through transcriptional or post-translational mechanisms in a tissue-restricted and signal-specific manner. The large number of BH3-only proteins, their unique subcellular localization, protein-interaction network and diverse modes of activation suggest specialization of their damage-sensing function, ensuring that the core apoptotic machinery is poised to receive input from a wide range of cellular stress signals. The apoptotic response initiated by the activation of BH3-only proteins ultimately culminates in allosteric activation of pro-apoptotic BAX and BAK, the gateway proteins to the mitochondrial pathway of apoptosis. From activation of BH3-only proteins to oligomerization of BAX and BAK and mitochondrial outer membrane permeabilization, an intricate network of interactions between the pro- and anti-apoptotic members of the BCL-2 family orchestrates the decision to undergo apoptosis. Beyond regulation of apoptosis, multiple BCL-2 proteins have recently emerged as active components of select homeostatic pathways carrying other cellular functions. This review focuses on BAD, which was the first BH3-only protein linked to proximal survival signals through phosphorylation by survival kinases. In addition to findings that delineated the physiological role of BAD in apoptosis and its dynamic regulation by phosphorylation, studies pointing to new roles for this protein in other physiological pathways, such as glucose metabolism, are highlighted. By executing its 'day' and 'night' jobs in metabolism and apoptosis, respectively, BAD helps coordinate mitochondrial fuel metabolism and the apoptotic machinery.
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Gregg C, Kyryakov P, Titorenko VI. Purification of mitochondria from yeast cells. J Vis Exp 2009:1417. [PMID: 19704406 DOI: 10.3791/1417] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Mitochondria are the main site of ATP production during aerobic metabolism in eukaryotic non-photosynthetic cells. These complex organelles also play essential roles in apoptotic cell death, cell survival, mammalian development, neuronal development and function, intracellular signalling, and longevity regulation. Our understanding of these complex biological processes controlled by mitochondria relies on robust methods for assessing their morphology, their protein and lipid composition, the integrity of their DNA, and their numerous vital functions. The budding yeast Saccharomyces cerevisiae, a genetically and biochemically manipulable unicellular eukaryote with annotated genome and well-defined proteome, is a valuable model for studying the molecular and cellular mechanisms underlying essential biological functions of mitochondria. For these types of studies, it is crucial to have highly pure mitochondria. Here we present a detailed description of a rapid and effective method for purification of yeast mitochondria. This method enables the isolation of highly pure mitochondria that are essentially free of contamination by other organelles and retain their structural and functional integrity after their purification. Mitochondria purified by this method are suitable for cell-free reconstitution of essential mitochondrial processes and can be used for the analysis of mitochondrial structure and functions, mitochondrial proteome and lipidome, and mitochondrial DNA.
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Montes-Rodríguez CJ, Alavez S, Soria-Gómez E, Rueda-Orozco PE, Guzman K, Morán J, Prospéro-García O. BCL-2 and BAX proteins expression throughout the light-dark cycle and modifications induced by sleep deprivation and rebound in adult rat brain. J Neurosci Res 2009; 87:1602-9. [DOI: 10.1002/jnr.21987] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Heme oxygenase-1 prevents hyperthyroidism induced hepatic damage via an antioxidant and antiapoptotic pathway. J Surg Res 2009; 164:266-75. [PMID: 19665148 DOI: 10.1016/j.jss.2009.04.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 03/16/2009] [Accepted: 04/03/2009] [Indexed: 12/15/2022]
Abstract
BACKGROUND The exact pathogenesis of hepatic dysfunction in hyperthyroidism is still unknown. We aimed to investigate the pathogenesis of liver dysfunction caused by hyperthyroidism through inducing heme oxygenase-1 (HO-1) expression, which has antioxidant and anti-apoptotic properties. METHODS Rats were divided into six groups: untreated (group 1), treated with zinc protoporphyrin (ZnPP) (group 2), treated with hemin (group 3), treated with tri-iodothyronine (T3) (group 4), treated with T3 and ZnPP (group 5), and treated with T3 and hemin (group 6). After 22 d, oxidative stress and antioxidant enzymes and the expression of HO-1, mitochondrial permeability transition, cytochrome c, Bax, Bcl-2, caspase-3, caspase-8, and caspase-3 activity, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay were examined. RESULTS Hyperthyroidism induced oxidative stress of liver tissue was ameliorated by HO-1 induction. Administration of hemin (HO-1 inducer) increased Bcl-2 expression. Decreased expression of cytochrome c was accompanied by a decrease in caspase-3, caspase-8, Bax expression, and caspase-3 activity. The apoptotic activity and oxidative damage were found to be increased by the administration of ZnPP (HO-1 inhibitor). Immunohistochemistry findings supported these results. CONCLUSION HO-1 induction plays a protective role in the pathogenesis of the liver dysfunction in hyperthyroidism. This effect is dependent on modulation of the antiapoptotic and antioxidative pathways by HO-1 expression.
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Krajewska M, Kitada S, Winter JN, Variakojis D, Lichtenstein A, Zhai D, Cuddy M, Huang X, Luciano F, Baker CH, Kim H, Shin E, Kennedy S, Olson AH, Badzio A, Jassem J, Meinhold-Heerlein I, Duffy MJ, Schimmer AD, Tsao M, Brown E, Sawyers A, Andreeff M, Mercola D, Krajewski S, Reed JC. Bcl-B expression in human epithelial and nonepithelial malignancies. Clin Cancer Res 2008; 14:3011-21. [PMID: 18483366 DOI: 10.1158/1078-0432.ccr-07-1955] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE Apoptosis plays an important role in neoplastic processes. Bcl-B is an antiapoptotic Bcl-2 family member, which is known to change its phenotype upon binding to Nur77/TR3. The expression pattern of this protein in human malignancies has not been reported. EXPERIMENTAL DESIGN We investigated Bcl-B expression in normal human tissues and several types of human epithelial and nonepithelial malignancy by immunohistochemistry, correlating results with tumor stage, histologic grade, and patient survival. RESULTS Bcl-B protein was strongly expressed in all normal plasma cells but found in only 18% of multiple myelomas (n = 133). Bcl-B immunostaining was also present in normal germinal center centroblasts and centrocytes and in approximately half of diffuse large B-cell lymphoma (n = 48) specimens, whereas follicular lymphomas (n = 57) did not contain Bcl-B. In breast (n = 119), prostate (n = 66), gastric (n = 180), and colorectal (n = 106) adenocarcinomas, as well as in non-small cell lung cancers (n = 82), tumor-specific overexpression of Bcl-B was observed. Bcl-B expression was associated with variables of poor prognosis, such as high tumor grade in breast cancer (P = 0.009), microsatellite stability (P = 0.0002), and left-sided anatomic location (P = 0.02) of colorectal cancers, as well as with greater incidence of death from prostate cancer (P = 0.005) and shorter survival of patients with small cell lung cancer (P = 0.009). Conversely, although overexpressed in many gastric cancers, Bcl-B tended to correlate with better outcome (P = 0.01) and more differentiated tumor histology (P < 0.0001). CONCLUSIONS Tumor-specific alterations in Bcl-B expression may define subsets of nonepithelial and epithelial neoplasms with distinct clinical behaviors.
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Affiliation(s)
- Maryla Krajewska
- Burnham Institute for Medical Research, La Jolla, California 92037, USA
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Bonner MR, Shen M, Liu CS, Divita M, He X, Lan Q. Mitochondrial DNA content and lung cancer risk in Xuan Wei, China. Lung Cancer 2008; 63:331-4. [PMID: 18691788 DOI: 10.1016/j.lungcan.2008.06.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 06/17/2008] [Accepted: 06/22/2008] [Indexed: 01/28/2023]
Abstract
Smoky coal contains polycyclic aromatic hydrocarbons (PAHs) and has been strongly implicated in etiology of lung cancer in Xuan Wei, China. While PAHs form bulky adducts in nuclear DNA, they have a 40-90-fold greater affinity for mitochondrial DNA (mtDNA). mtDNA content may increase to compensate for mtDNA damage. We conducted a population-based case-control study of lung cancer in Xuan Wei, China hypothesizing that mtDNA content is positively associated with lung cancer risk. Cases (n=122) and controls (n=121) were individually matched on age (+/-2 years), sex, village of residence, and current fuel type. Lifetime smoky coal use and potential confounders were determined with questionnaires. mtDNA was extracted from sputum and mtDNA content was determined with quantitative PCR. ORs and 95% CIs were calculated with unconditional logistic regression. mtDNA content >157 copies per cell was associated with lung cancer risk (OR=1.8; 95% CI=1.0-3.2) compared with those with <or=157 copies. In summary, mtDNA content was positively associated with lung cancer risk. Furthermore, mtDNA content was more strongly associated with lung cancer risk among older individuals. However, due to the small sample size, additional studies are needed to evaluate this potential association.
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Affiliation(s)
- Matthew R Bonner
- Department of Social and Preventive Medicine, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY 14214, United States.
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Low CP, Shui G, Liew LP, Buttner S, Madeo F, Dawes IW, Wenk MR, Yang H. Caspase-dependent and -independent lipotoxic cell-death pathways in fission yeast. J Cell Sci 2008; 121:2671-84. [PMID: 18653539 DOI: 10.1242/jcs.028977] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Understanding the mechanisms underlying lipid-induced cell death has significant implications in both cell biology and human diseases. Previously, we showed that fission-yeast Schizosaccharomyces pombe cells deficient in triacylglycerol synthesis display apoptotic markers upon entry into stationary phase. Here, we characterize the sequential molecular events that take place at the onset of cell death in S. pombe, including a surge of diacylglycerol, post-mitotic arrest, alterations in mitochondrial activities and in intracellular redox balance, chromatin condensation, nuclear-envelope fragmentation, and eventually plasma-membrane permeabilization. Our results demonstrated active roles of mitochondria and reactive oxygen species in cell death, and identified novel cell-death regulators--including metacaspase Pca1, BH3-domain protein Rad9, and diacylglycerol-binding proteins Pck1 and Bzz1. Most importantly, we show that, under different conditions and stimuli, failure to maintain intracellular-lipid homeostasis can lead to cell death with different phenotypic manifestations, genetic criteria and cellular mechanisms, pointing to the existence of multiple lipotoxic pathways in this organism. Our study represents the first in-depth analysis of cell-death pathways in S. pombe.
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Affiliation(s)
- Choon Pei Low
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Republic of Singapore
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The pleiotropic effects of heterologous Bax expression in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1449-65. [DOI: 10.1016/j.bbamcr.2007.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 12/14/2007] [Accepted: 12/30/2007] [Indexed: 12/27/2022]
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Shukla S, Gupta S. Apigenin-induced prostate cancer cell death is initiated by reactive oxygen species and p53 activation. Free Radic Biol Med 2008; 44:1833-45. [PMID: 18342637 PMCID: PMC2538676 DOI: 10.1016/j.freeradbiomed.2008.02.007] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 01/24/2008] [Accepted: 02/06/2008] [Indexed: 11/20/2022]
Abstract
Apigenin, a plant flavone, potentially activates wild-type p53 and induces apoptosis in cancer cells. We conducted detailed studies to understand its mechanism of action. Exposure of human prostate cancer 22Rv1 cells, harboring wild-type p53, to growth-suppressive concentrations (10-80 microM) of apigenin resulted in the stabilization of p53 by phosphorylation on critical serine sites, p14ARF-mediated downregulation of MDM2 protein, inhibition of NF-kappaB/p65 transcriptional activity, and induction of p21/WAF-1 in a dose- and time-dependent manner. Apigenin at these doses resulted in ROS generation, which was accompanied by rapid glutathione depletion, disruption of mitochondrial membrane potential, cytosolic release of cytochrome c, and apoptosis. Interestingly, we observed accumulation of a p53 fraction to the mitochondria, which was rapid and occurred between 1 and 3 h after apigenin treatment. All these effects were significantly blocked by pretreatment of cells with the antioxidant N-acetylcysteine, p53 inhibitor pifithrin-alpha, and enzyme catalase. Apigenin-mediated p53 activation and apoptosis were further attenuated by p53 antisense oligonucleotide treatment. Exposure of cells to apigenin led to a decrease in the levels of Bcl-XL and Bcl-2 and increase in Bax, triggering caspase activation. Treatment with the caspase inhibitors Z-VAD-FMK and DEVD-CHO partially rescued these cells from apigenin-induced apoptosis. In vivo, apigenin administration demonstrated p53-mediated induction of apoptosis in 22Rv1 tumors. These results indicate that apigenin-induced apoptosis in 22Rv1 cells is initiated by a ROS-dependent disruption of the mitochondrial membrane potential through transcriptional-dependent and -independent p53 pathways.
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Affiliation(s)
- Sanjeev Shukla
- Department of Urology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sanjay Gupta
- Department of Urology, Case Western Reserve University, Cleveland, OH 44106, USA
- University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA
- *Corresponding author. Department of Urology, Case Western Reserve University, Cleveland, OH 44106, USA. Fax: +1 216 368 0213. E-mail address: (S. Gupta)
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39
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Cheng WC, Leach KM, Hardwick JM. Mitochondrial death pathways in yeast and mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1272-9. [PMID: 18477482 DOI: 10.1016/j.bbamcr.2008.04.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 04/14/2008] [Accepted: 04/25/2008] [Indexed: 12/30/2022]
Abstract
In mammals, mitochondria are important mediators of programmed cell death, and this process is often regulated by Bcl-2 family proteins. However, a role for mitochondria-mediated cell death in non-mammalian species is more controversial. New evidence from a variety of sources suggests that mammalian mitochondrial fission/division proteins also have the capacity to promote programmed cell death, which may involve interactions with Bcl-2 family proteins. Homologues of these fission factors and several additional mammalian cell death regulators are conserved in flies, worms and yeast, and have been suggested to regulate programmed cell death in these species as well. However, the molecular mechanisms by which these phylogenetically conserved proteins contribute to cell death are not known for any species. Some have taken the conserved pro-death activity of mitochondrial fission factors to mean that mitochondrial fission per se, or failed attempts to undergo fission, are directly involved in cell death. Other evidence suggests that the fission function and the cell death function of these factors are separable. Here we consider the evidence for these arguments and their implications regarding the origins of programmed cell death.
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Affiliation(s)
- Wen-Chih Cheng
- W Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD 21205, USA
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40
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Lack of pathology in a triple transgenic mouse model of Alzheimer's disease after overexpression of the anti-apoptotic protein Bcl-2. J Neurosci 2008; 28:3051-9. [PMID: 18354008 DOI: 10.1523/jneurosci.5620-07.2008] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of plaques containing beta-amyloid (Abeta) and neurofibrillary tangles (NFTs) consisting of modified tau. Although Abeta deposition is thought to precede the formation of NFTs in AD, the molecular steps connecting these two pathologies is not known. Previous studies have suggested that caspase activation plays an important role in promoting the pathology associated with AD. To further understand the contribution of caspases in disease progression, a triple transgenic Alzheimer's mouse model overexpressing the anti-apoptotic protein Bcl-2 was generated. Here we show that overexpression of Bcl-2 limited caspase-9 activation and reduced the caspase cleavage of tau. Moreover, overexpression of Bcl-2 attenuated the processing of APP (amyloid precursor protein) and tau and reduced the number of NFTs and extracellular deposits of Abeta associated with these animals. In addition, overexpression of Bcl-2 in 3xTg-AD mice improved place recognition memory. These findings suggest that the activation of apoptotic pathways may be an early event in AD and contributes to the pathological processes that promote the disease mechanisms underlying AD.
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41
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Low CP, Yang H. Programmed cell death in fission yeast Schizosaccharomyces pombe. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1335-49. [PMID: 18328827 DOI: 10.1016/j.bbamcr.2008.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 01/25/2008] [Accepted: 02/04/2008] [Indexed: 02/06/2023]
Abstract
Yeasts have proven to be invaluable, genetically tractable systems to study various fundamental biological processes including programmed cell death. Recent advances in the elucidation of the molecular pathways underlying apoptotic cell death in yeasts have revealed remarkable similarities to mammalian apoptosis at cellular, organelle and macromolecular levels, thus making a strong case for the relevance of yeast models of regulated cell death. Programmed cell death has been reported in fission yeast Schizosaccharomyces pombe, primarily in the contexts of perturbed intracellular lipid metabolism, defective DNA replication, improper mitotic entry, chronological and replicative aging. Here we review the current understanding of the programmed cell death in fission yeast, paying particular attention to lipid-induced cell death. We discuss our recent findings that fission yeast exhibits plasticity of apoptotic and non-apoptotic modes of cell death in response to different lipid stimuli and growth conditions, and that mitochondria, reactive oxygen species and novel cell death mediators including metacaspase Pca1, SpRad9 and Pck1 are involved in the lipotoxic cell death. We also present perspectives on how various aspects of the cell and molecular biology of this organism can be explored to shed light on the governing principles underlying lipid-mediated signaling and cell demise.
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Affiliation(s)
- Choon Pei Low
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Republic of Singapore
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42
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Gannavaram S, Vedvyas C, Debrabant A. Conservation of the pro-apoptotic nuclease activity of endonuclease G in unicellular trypanosomatid parasites. J Cell Sci 2008; 121:99-109. [DOI: 10.1242/jcs.014050] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Endonuclease G is a mitochondrial protein implicated in DNA fragmentation during apoptosis in cell types ranging from fungi to mammals. Features of programmed cell death have been reported in a number of single-celled organisms, including the human trypanosomatid parasites Leishmania and Trypanosoma. However, the protozoan cell death pathways and the effector molecules involved in such processes remain to be identified. In this report, we describe the pro-apoptotic function of endonuclease G in trypanosomatid parasites. Similar to metazoans, trypanosome endoG showed intrinsic nuclease activity, is localized in mitochondria and is released from this organelle when cell death is triggered. Overexpression of endoG strongly promoted apoptotic cell death under oxidant or differentiation-related stress in Leishmania and, conversely, loss of endoG expression conferred robust resistance to oxidant-induced cell death in T. brucei. These data demonstrate the conservation of the pro-apoptotic endonuclease activity of endoG in these evolutionarily ancient eukaryotic organisms. Furthermore, nuclear DNA degradation by endoG upon release from mitochondria might represent a caspase-independent cell death mechanism in trypanosomatid parasites as genes encoding caspase-like proteins have not been identified in their genomes.
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Affiliation(s)
- Sreenivas Gannavaram
- Laboratory of Bacterial, Parasitic and Unconventional Agents, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda MD 20892, USA
| | - Chetan Vedvyas
- Laboratory of Bacterial, Parasitic and Unconventional Agents, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda MD 20892, USA
| | - Alain Debrabant
- Laboratory of Bacterial, Parasitic and Unconventional Agents, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda MD 20892, USA
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43
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van Doorn WG, Woltering EJ. Physiology and molecular biology of petal senescence. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:453-80. [PMID: 18310084 DOI: 10.1093/jxb/erm356] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Petal senescence is reviewed, with the main emphasis on gene expression in relation to physiological functions. Autophagy seems to be the major mechanism for large-scale degradation of macromolecules, but it is still unclear if it contributes to cell death. Depending on the species, petal senescence is controlled by ethylene or is independent of this hormone. EIN3-like (EIL) transcription factors are crucial in ethylene-regulated senescence. The presence of adequate sugar levels in the cell delays senescence and prevents an increase in the levels of EIL mRNA and the subsequent up-regulation of numerous senescence-associated genes. A range of other transcription factors and regulators are differentially expressed in ethylene-sensitive and ethylene-insensitive petal senescence. Ethylene-independent senescence is often delayed by cytokinins, but it is still unknown whether these are natural regulators. A role for caspase-like enzymes or metacaspases has as yet not been established in petal senescence, and a role for proteins released by organelles such as the mitochondrion has not been shown. The synthesis of sugars, amino acids, and fatty acids, and the degradation of nucleic acids, proteins, lipids, fatty acids, and cell wall components are discussed. It is claimed that there is not enough experimental support for the widely held view that a gradual increase in cell leakiness, resulting from gradual plasma membrane degradation, is an important event in petal senescence. Rather, rupture of the vacuolar membrane and subsequent rapid, complete degradation of the plasma membrane seems to occur. This review recommends that more detailed analysis be carried out at the level of cells and organelles rather than at that of whole petals.
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Affiliation(s)
- Wouter G van Doorn
- Wageningen University and Research Centre, PO Box 17, 6700 AA Wageningen, The Netherlands.
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44
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Choi AO, Brown SE, Szyf M, Maysinger D. Quantum dot-induced epigenetic and genotoxic changes in human breast cancer cells. J Mol Med (Berl) 2007; 86:291-302. [DOI: 10.1007/s00109-007-0274-2] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 08/14/2007] [Accepted: 09/24/2007] [Indexed: 12/21/2022]
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45
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Schwartz PS, Manion MK, Emerson CB, Fry JS, Schulz CM, Sweet IR, Hockenbery DM. 2-Methoxy antimycin reveals a unique mechanism for Bcl-x(L) inhibition. Mol Cancer Ther 2007; 6:2073-80. [PMID: 17620436 DOI: 10.1158/1535-7163.mct-06-0767] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Overexpression of Bcl-x(L) in multiple cancers correlates with resistance to chemotherapy and radiation therapy, and provides a rationale for development of small-molecule Bcl-x(L) inhibitors. Based on knockout studies, nonneoplastic cells also require Bcl-x(L) survival functions, particularly when challenged with cytotoxic agents. We analyze the selective cytotoxicity of one Bcl-x(L) inhibitor, 2-methoxy antimycin A, toward cells with excess exogenous Bcl-x(L) in isogenic cell line pairs. This selectivity, characteristic of a gain-of-function mechanism, is not shared by other known Bcl-x(L) inhibitors, including BH3I-2, HA14-1, ABT-737, gossypol, or the stapled BH3 helical peptide SAHB-BID. We show that Bcl-x(L) overexpression induces a shift in energy metabolism from oxidative phosphorylation to glycolysis. Treatment with 2-methoxy antimycin A acutely reverses the metabolic effects of Bcl-x(L), causing mitochondrial hyperpolarization and a progressive increase in mitochondrial NAD(P)H. We identify an additional small-molecule Bcl-x(L) inhibitor, NSC 310343, establishing a class of Bcl-x(L) inhibitors with gain-of-function activity. In contrast to other Bcl-x(L) inhibitors, combining gain-of-function Bcl-x(L) inhibitors with a standard inducer of apoptosis, staurosporine, enhances selective cytotoxicity toward Bcl-x(L)-overexpressing cells. These results provide an example of the intersection of bioenergetic metabolism and Bcl-x(L) functions and suggest a metabolic basis for the gain-of-function mechanism of Bcl-x(L) inhibitors.
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Affiliation(s)
- Pamela S Schwartz
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue D2-190, Seattle, WA 98109, USA
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46
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Zeidan YH, Wu BX, Jenkins RW, Obeid LM, Hannun YA. A novel role for protein kinase Cdelta-mediated phosphorylation of acid sphingomyelinase in UV light-induced mitochondrial injury. FASEB J 2007; 22:183-93. [PMID: 17698617 DOI: 10.1096/fj.07-8967com] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Multiple studies have addressed the mechanisms by which ultraviolet (UV) light induces cell death, and a few have focused on stress mediators such as acid sphingomyelinase (ASMase) or protein kinase Cdelta (PKCdelta). Based on a recent study that identified a novel mechanism of activation of ASMase through phosphorylation, the current study was undertaken to determine the upstream mechanisms regulating ASMase in response to UV and to investigate the role of ASMase and its phosphorylation at S508 as an integral event during UV light-induced cell death. Exposure of MCF-7 breast cancer cells to UV light type C (UVC) transiently activated ASMase with maximal activity detected at 10 min postirradiation. A significant increase in C16-ceramide was detected concomitant with a decrease in C16-sphingomyelin. In marked contrast, cells overexpressing the ASMase(S508A) mutant, which could not be phosphorylated, had no change in either ASMase activity or ceramide levels post-UV radiation. Loss of PKCdelta by RNA interference or its inhibition by rottlerin blocked ASMase phosphorylation and membrane targeting, thus implicating PKCdelta upstream of ASMase activation by UV light. Further investigations revealed that UV radiation altered mitochondrial morphology from elongated tubules to fragmented perinuclear organelles, consistent with the onset of the apoptotic cascade. Importantly, cells overexpressing ASMase(S508A) were protected (>50%) from UV light-induced mitochondrial fragmentation. Mechanistically, the results showed that ASMase(S508A) cells had 50% less active Bax than ASMase(WT) cells. These molecular differences culminated in resistance of ASMase(S508) cells to UVC-induced cell death (25%) as compared to ASMase(WT) cells (46%). Taken together, this study provides key molecular insights into activation of ASMase in response to UV light, the role of PKCdelta in this activation, and the role of ASMase in mediating apoptotic responses.
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Affiliation(s)
- Youssef H Zeidan
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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47
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Tseng HC, Chow SN, Huang LY, Chien CH. Desialylation of human cancer cells leading apoptosis by treatment with purified and overexpressed nanI cloned from Clostridium perfringens ATCC 10543. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2006.11.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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48
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Sevrioukov EA, Burr J, Huang EW, Assi HH, Monserrate JP, Purves DC, Wu JN, Song EJ, Brachmann CB. Drosophila Bcl-2 proteins participate in stress-induced apoptosis, but are not required for normal development. Genesis 2007; 45:184-93. [PMID: 17417787 DOI: 10.1002/dvg.20279] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many developing tissues require programmed cell death (PCD) for proper formation. In mice and C. elegans, developmental PCD is regulated by the Bcl-2 family of proteins. Two bcl-2 genes are encoded in the Drosophila genome (debcl/dBorg1/Drob-1/dBok and buffy/dBorg2) and previous RNAi-based studies suggested a requirement for these in embryonic development. However, we report here that, despite the fact that many tissues in fruit flies are shaped by PCD, deletion of the bcl-2 genes does not perturb normal development. We investigated whether the fly bcl-2 genes regulate non-apoptotic processes that require caspases, but found these to be bcl-2 gene-independent. However, irradiation of the mutants demonstrates that DNA damage-induced apoptosis, mediated by Reaper, is blocked by buffy and that debcl is required to inhibit buffy. Our results demonstrate that developmental PCD regulation in the fly does not rely upon the Bcl-2 proteins, but that they provide an added layer of protection in the apoptotic response to stress.
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Affiliation(s)
- Evgueni A Sevrioukov
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, California 92697, USA
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49
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Cho YE, Ko JH, Kim YJ, Yim JH, Kim SM, Park JH. mHGTD-P mediates hypoxic neuronal cell death via the release of apoptosis-inducing factor. Neurosci Lett 2007; 416:144-9. [PMID: 17316997 DOI: 10.1016/j.neulet.2007.01.073] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 01/31/2007] [Accepted: 01/31/2007] [Indexed: 01/05/2023]
Abstract
HGTD-P is a pro-apoptotic target protein of hypoxia-inducible factor 1alpha (HIF-1alpha). It localizes to mitochondria and induces the mitochondrial permeability transition through its interaction with voltage dependent anion channels when overexpressed. However, the molecular mechanisms responsible for its induction and its downstream effector molecules required during cell death, especially in neuronal cell death by hypoxia, are largely unknown. We performed this work to elucidate the effects of the pro-apoptotic protein HGTD-P on neuronal cell death induced by hypoxia and to investigate the cell death mechanisms activated during this process. In this report, we show that mouse HGTD-P (mHGTD-P) is transcriptionally increased by hypoxia and that its overexpression triggers neuronal cell death with affected cells displaying shrunken cytoplasm and condensed pyknotic nuclei in a caspase-independent manner. In addition, suppression of endogenous mHGTD-P expression by siRNA rescues neuronal cells from hypoxic injury. Finally, we show that mHGTD-P induces the mitochondrial release of apoptosis-inducing factor into the cytoplasm. Taken together, our data suggest that mHGTD-P participates in caspase-independent hypoxic neuronal cell death. Future studies will be necessary in order to determine whether hypoxia-induced mHGTD-P expression has any relevance in an ischemic animal model or clinical hypoxia-induced disorders.
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Affiliation(s)
- Young-Eun Cho
- Department of Pathology and Biomedical Research Center for Reactive Oxygen Species, College of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
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50
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Büttner S, Eisenberg T, Carmona-Gutierrez D, Ruli D, Knauer H, Ruckenstuhl C, Sigrist C, Wissing S, Kollroser M, Fröhlich KU, Sigrist S, Madeo F. Endonuclease G regulates budding yeast life and death. Mol Cell 2007; 25:233-46. [PMID: 17244531 DOI: 10.1016/j.molcel.2006.12.021] [Citation(s) in RCA: 269] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Revised: 11/11/2006] [Accepted: 12/27/2006] [Indexed: 12/20/2022]
Abstract
Endonuclease G (EndoG) is located in mitochondria yet translocates into the nucleus of apoptotic cells during human degenerative diseases. Nonetheless, a direct involvement of EndoG in cell-death execution remains equivocal, and the mechanism for mitochondrio-nuclear translocation is not known. Here, we show that the yeast homolog of EndoG (Nuc1p) can efficiently trigger apoptotic cell death when excluded from mitochondria. Nuc1p induces apoptosis in yeast independently of metacaspase or of apoptosis inducing factor. Instead, the permeability transition pore, karyopherin Kap123p, and histone H2B interact with Nuc1p and are required for cell death upon Nuc1p overexpression, suggesting a pathway in which mitochondrial pore opening, nuclear import, and chromatin association are successively involved in EndoG-mediated death. Deletion of NUC1 diminishes apoptotic death when mitochondrial respiration is increased but enhances necrotic death when oxidative phosphorylation is repressed, pointing to dual--lethal and vital--roles for EndoG.
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Affiliation(s)
- Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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