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Cigarette Smoke Extract Induces p38 MAPK-Initiated, Fas-Mediated Eryptosis. Int J Mol Sci 2022; 23:ijms232314730. [PMID: 36499060 PMCID: PMC9738679 DOI: 10.3390/ijms232314730] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
Eryptosis is a physiological mechanism for the clearance of senescent or damaged erythrocytes by phagocytes. Excessive eryptosis is stimulated under several pathologies and associated with endothelial injury and thrombosis. Cigarette smoke (CS) is an established risk factor for vascular diseases and cigarette smokers have high-levels of eryptotic erythrocytes. This study, for the first time, investigates the mechanism by which CS damages red blood cells (RBCs). CS extract (CSE) from commercial cigarettes was prepared and standardized for nicotine content. Cytofluorimetric analysis demonstrated that treatment of human RBCs with CSE caused dose-dependent, phosphatidylserine externalization and cell shrinkage, hallmarks of apoptotic death. CSE did not affect cellular levels of Ca2+, reactive oxygen species (ROS) or glutathione (GSH). Immununoprecipitation and immunoblotting revealed the assembly of the death-inducing signaling complex (DISC) and oligomerization of Fas receptor as well as cleaved caspase-8 and caspase-3 within 6 h from the treatment. At the same time-interval, CSE elicited neutral sphyngomielinase (nSMase) activity-dependent ceramide formation and phosphorylation of p38 MAPK. Through specific inhibitors' nSMase, caspase-8 or p38 MAPK activities, we demonstrated that p38 MAPK activation is required for caspase-8-mediated eryptosis and that ceramide generation is initiator caspase-dependent. Finally, ex vivo analysis detected phosphorylated p38 MAPK (p-p38) and Fas-associated signaling complex in erythrocytes from cigarette smokers. In conclusion, our study demonstrates that CSE exposure induces in erythrocytes an extrinsic apoptotic pathway involving p38 MAPK-initiated DISC formation followed by activation of caspase-8/caspase-3 via ceramide formation.
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Perla V, Nadimi M, Reddy R, Hankins GR, Nimmakayala P, Harris RT, Valluri J, Sirbu C, Reddy UK. Effect of ghost pepper on cell proliferation, apoptosis, senescence and global proteomic profile in human renal adenocarcinoma cells. PLoS One 2018; 13:e0206183. [PMID: 30379886 PMCID: PMC6209291 DOI: 10.1371/journal.pone.0206183] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/07/2018] [Indexed: 12/19/2022] Open
Abstract
Chili peppers are an important constituent of many foods and contain medicinally valuable compounds, such as capsaicin and dihydrocapsaicin. As various dietary botanicals have anticancer properties, this study was aimed to examine the effect of Ghost pepper (Bhut Jolokia), one of the hottest chili peppers in the world, on cell proliferation, apoptosis, senescence and the global proteomic profile in human renal cell adenocarcinoma in vitro. 769-P human renal adenocarcinoma cells were cultured on RPMI-1640 media supplemented with fetal bovine serum (10%) and antibiotic-antimycotic solution (1%). Treatment stock solutions were prepared in ethanol. Cell proliferation was tested with phenol red-free media with capsaicin (0-400 μM), dihydrocapsaicin (0-400 μM), capsaicin + dihydrocapsaicin (5:1), and dry Ghost peppers (0-3 g L-1) for 24, 48 and 72 h. Polycaspase and senescence associated-beta-galactosidase (SA-beta-gal) activities were tested with capsaicin (400 μM), dihydrocapsaicin (400 μM), capsaicin (400 μM) + dihydrocapsaicin (80 μM), and ghost pepper (3 g L-1) treatments. Global proteomic profile of cells in control and ghost pepper treatment (3 g L-1) was analyzed after 6 h by a shotgun proteomic approach using tandem mass spectrometry. At 24 h after treatment (24 HAT), relative to control, cell proportion with capsaicin (400 μM), dihydrocapsaicin (400 μM), capsaicin (400 μM) + dihydrocapsaicin (80 μM), and ghost pepper (3 g L-1) treatments was reduced to 36%, 18%, 33% and 20%, respectively, and further reduced at 48 and 72 HAT. All treatments triggered an early polycaspase response. SA-beta-gal activity was normal or suppressed with all treatments. About 68,220 protein isoforms were identified by shotgun proteomic approach. Among these, about 8.2% were significantly affected by ghost pepper. Ghost pepper regulated various proteins involved in intrinsic and extrinsic apoptotic pathways, Ras, Rb/E2F, p53, TGF-beta, WNT-beta catenin, and calcium induced cell death pathways. Ghost pepper also induced changes in proteins related to methylation, acetylation, genome stability, cell cycle check points, carbohydrate, protein and other metabolism and cellular mechanisms. Ghost pepper exhibited antiproliferation activity by inducing apoptosis through a complex network of proteins in human renal cell adenocarcinoma in vitro.
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Affiliation(s)
- Venu Perla
- Gus R. Douglass Land-Grant Institute and Department of Biology, West Virginia State University, Institute, West Virginia, United States of America
| | - Marjan Nadimi
- Gus R. Douglass Land-Grant Institute and Department of Biology, West Virginia State University, Institute, West Virginia, United States of America
| | - Rishi Reddy
- Gus R. Douglass Land-Grant Institute and Department of Biology, West Virginia State University, Institute, West Virginia, United States of America
| | - Gerald R. Hankins
- Gus R. Douglass Land-Grant Institute and Department of Biology, West Virginia State University, Institute, West Virginia, United States of America
| | - Padma Nimmakayala
- Gus R. Douglass Land-Grant Institute and Department of Biology, West Virginia State University, Institute, West Virginia, United States of America
| | - Robert T. Harris
- Gus R. Douglass Land-Grant Institute and Department of Biology, West Virginia State University, Institute, West Virginia, United States of America
| | - Jagan Valluri
- Department of Biological Sciences, One John Marshall Drive, Marshall University, Huntington, West Virginia, United States of America
| | - Cristian Sirbu
- Center for Cancer Research, Charleston Area Medical Center, SE, Charleston, West Virginia, United States of America
| | - Umesh K. Reddy
- Gus R. Douglass Land-Grant Institute and Department of Biology, West Virginia State University, Institute, West Virginia, United States of America
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Hage-Sleiman R, Hamze AB, El-Hed AF, Attieh R, Kozhaya L, Kabbani S, Dbaibo G. Ceramide inhibits PKCθ by regulating its phosphorylation and translocation to lipid rafts in Jurkat cells. Immunol Res 2017; 64:869-86. [PMID: 26798039 DOI: 10.1007/s12026-016-8787-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Protein kinase C theta (PKCθ) is a novel, calcium-independent member of the PKC family of kinases that was identified as a central player in T cell signaling and proliferation. Upon T cell activation by antigen-presenting cells, PKCθ gets phosphorylated and activated prior to its translocation to the immunological synapse where it couples with downstream effectors. PKCθ may be regulated by ceramide, a crucial sphingolipid that is known to promote differentiation, growth arrest, and apoptosis. To further investigate the mechanism, we stimulated human Jurkat T cells with either PMA or anti-CD3/anti-CD28 antibodies following induction of ceramide accumulation by adding exogenous ceramide, bacterial sphingomyelinase, or Fas ligation. Our results suggest that ceramide regulates the PKCθ pathway through preventing its critical threonine 538 (Thr538) phosphorylation and subsequent activation, thereby inhibiting the kinase's translocation to lipid rafts. Moreover, this inhibition is not likely to be a generic effect of ceramide on membrane reorganization. Other lipids, namely dihydroceramide, palmitate, and sphingosine, did not produce similar effects on PKCθ. Addition of the phosphatase inhibitors okadaic acid and calyculin A reversed the inhibition exerted by ceramide, and this suggests involvement of a ceramide-activated protein phosphatase. Such previously undescribed mechanism of regulation of PKCθ raises the possibility that ceramide, or one of its derivatives, and may prove valuable in novel therapeutic approaches for disorders involving autoimmunity or excessive inflammation-where PKCθ plays a critical role.
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Affiliation(s)
- Rouba Hage-Sleiman
- Department of Biology, Faculty of Sciences, Lebanese University, Hadath, Lebanon
| | - Asmaa B Hamze
- Department of Biomedical Science, Faculty of Health Sciences, Global University, Batrakiyye, Beirut, Lebanon
| | - Aimée F El-Hed
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Randa Attieh
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Lina Kozhaya
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Sarah Kabbani
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon
| | - Ghassan Dbaibo
- Department of Pediatrics and Adolescent Medicine, Center for Infectious Diseases Research, Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut, Lebanon.
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Kraft ML. Sphingolipid Organization in the Plasma Membrane and the Mechanisms That Influence It. Front Cell Dev Biol 2017; 4:154. [PMID: 28119913 PMCID: PMC5222807 DOI: 10.3389/fcell.2016.00154] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 12/27/2016] [Indexed: 11/13/2022] Open
Abstract
Sphingolipids are structural components in the plasma membranes of eukaryotic cells. Their metabolism produces bioactive signaling molecules that modulate fundamental cellular processes. The segregation of sphingolipids into distinct membrane domains is likely essential for cellular function. This review presents the early studies of sphingolipid distribution in the plasma membranes of mammalian cells that shaped the most popular current model of plasma membrane organization. The results of traditional imaging studies of sphingolipid distribution in stimulated and resting cells are described. These data are compared with recent results obtained with advanced imaging techniques, including super-resolution fluorescence detection and high-resolution secondary ion mass spectrometry (SIMS). Emphasis is placed on the new insight into the sphingolipid organization within the plasma membrane that has resulted from the direct imaging of stable isotope-labeled lipids in actual cell membranes with high-resolution SIMS. Super-resolution fluorescence techniques have recently revealed the biophysical behaviors of sphingolipids and the unhindered diffusion of cholesterol analogs in the membranes of living cells are ultimately in contrast to the prevailing hypothetical model of plasma membrane organization. High-resolution SIMS studies also conflicted with the prevailing hypothesis, showing sphingolipids are concentrated in micrometer-scale membrane domains, but cholesterol is evenly distributed within the plasma membrane. Reductions in cellular cholesterol decreased the number of sphingolipid domains in the plasma membrane, whereas disruption of the cytoskeleton eliminated them. In addition, hemagglutinin, a transmembrane protein that is thought to be a putative raft marker, did not cluster within sphingolipid-enriched regions in the plasma membrane. Thus, sphingolipid distribution in the plasma membrane is dependent on the cytoskeleton, but not on favorable interactions with cholesterol or hemagglutinin. The alternate views of plasma membrane organization suggested by these findings are discussed.
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Affiliation(s)
- Mary L Kraft
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana, IL, USA
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Metabolic Conversion of Ceramides in HeLa Cells - A Cholesteryl Phosphocholine Delivery Approach. PLoS One 2015; 10:e0143385. [PMID: 26599810 PMCID: PMC4658033 DOI: 10.1371/journal.pone.0143385] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/04/2015] [Indexed: 11/19/2022] Open
Abstract
Ceramides can be delivered to cultured cells without solvents in the form of complexes with cholesteryl phosphocholine. We have analysed the delivery of three different radiolabeled D-erythro-ceramides (C6-Cer, C10-Cer and C16-Cer) to HeLa cells, and followed their metabolism as well as the cell viability. We found that all three ceramides were successfully taken up by HeLa cells when complexed to CholPC in an equimolar ratio, and show that the ceramides show different rates of cellular uptake and metabolic fate. The C6-Cer had the highest incorporation rate, followed by C10-Cer and C16-Cer, respectively. The subsequent effect on cell viability strongly correlated with the rate of incorporation, where C6-Cer had the strongest apoptotic effects. Low-dose (1 μM) treatment with C6-Cer favoured conversion of the precursor to sphingomyelin, whereas higher concentrations (25–100 μM) yielded increased conversion to C6-glucosylceramide. Similar results were obtained for C10-Cer. In the lower-dose C16-Cer experiments, most of the precursor was degraded, whereas at high-dose concentrations the precursor remained un-metabolized. Using this method, we demonstrate that ceramides with different chain lengths clearly exhibit varying rates of cellular uptake. The cellular fate of the externally delivered ceramides are clearly connected to their rate of incorporation and their subsequent effects on cell viability may be in part determined by their chain length.
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Ziegler C, Finke J, Grüllich C. Features of cell death, mitochondrial activation and caspase dependence of rabbit anti-T-lymphocyte globulin signaling in lymphoblastic Jurkat cells are distinct from classical apoptosis signaling of CD95. Leuk Lymphoma 2015; 57:177-82. [PMID: 25927246 DOI: 10.3109/10428194.2015.1044449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Rabbit anti-T-lymphocyte-globulin (ATG) is used for immunosuppression in organ and stem cell transplantation. The aim of this study was to investigate ATG-induced cell death compared to CD95-signaling of apoptosis. We measured features of cell death at the cell membrane, mitochondria, nuclei and caspase-3 cleavage. We used the following inhibitors: the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp (O-Me)-fluoromethyl ketone (zVAD-fmk), the serine protease inhibitors 3,4 dichloroisocoumarin (DCI) and N-alpha-tosyl-L-lysinyl-chloromethylketone (TLCK) and the reducing agent N-acetycysteine (NAC). ATG-induced cellular changes were rapid, included mitochondrial membrane permeability (MMP) induction and annexin V/propidium iodide (PI) positivity but little caspase-3 activation and nuclear morphology changes. MMP was not sensitive to caspase inhibition, serine protease inhibition with DCI moderately reduced MMP. These findings were in contrast to CD95-signaling. Interestingly, TLCK massively augmented CD95-induced MMP which could be abrogated by NAC. In conclusion, ATG-signaling differs in features and kinetics from CD95-induced apoptosis with caspase-independent mechanisms involved in MMP.
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Affiliation(s)
- Christian Ziegler
- a Department of Medical Oncology , National Center for Tumor Diseases, Heidelberg University Hospital , Heidelberg , Germany.,b Department of Hematology and Oncology , Albert Ludwigs-University Medical Center Freiburg , Freiburg , Germany.,c Department of Hematology and Oncology , Charité Medical Center Berlin , Campus Virchow Klinik, Berlin, Germany
| | - Jürgen Finke
- b Department of Hematology and Oncology , Albert Ludwigs-University Medical Center Freiburg , Freiburg , Germany
| | - Carsten Grüllich
- a Department of Medical Oncology , National Center for Tumor Diseases, Heidelberg University Hospital , Heidelberg , Germany.,b Department of Hematology and Oncology , Albert Ludwigs-University Medical Center Freiburg , Freiburg , Germany
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Wang M, Yu T, Zhu C, Sun H, Qiu Y, Zhu X, Li J. Resveratrol triggers protective autophagy through the ceramide/Akt/mTOR pathway in melanoma B16 cells. Nutr Cancer 2014; 66:435-40. [PMID: 24579778 DOI: 10.1080/01635581.2013.878738] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Resveratrol (3,5,4'-trihydroxy-trans-stilbene, RSV), a natural polyphenolic compound, is known as a promising anti-cancer agent. In this study, we showed that RSV could inhibit the growth of B16 cells via induction of apoptosis. Moreover, our results showed for the first time that RSV induced autophagy in B16 cells, which might occur through ceramide accumulation and Akt/mTOR pathway inhibition. Inhibition of autophagy by an autophagic inhibitor 3-methyladenine (3-MA) or si-Beclin 1 enhanced RSV-induced cytotoxicity and apoptosis. Thus, autophagy inhibition represents a promising approach to improve the efficacy of RSV in the treatment of patients with melanoma.
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Affiliation(s)
- Meng Wang
- a Department of Oncology , Shandong Jining No.1 People's Hospital , Jining , China
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Lai X, Kang X, Zeng L, Li J, Yang Y, Liu D. The protective effects and genetic pathways of thorn grape seeds oil against high glucose-induced apoptosis in pancreatic β-cells. Altern Ther Health Med 2014; 14:10. [PMID: 24405938 PMCID: PMC3893577 DOI: 10.1186/1472-6882-14-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/07/2014] [Indexed: 01/26/2023]
Abstract
Background Excessive apoptosis of β-cell is closely related to diabetes mellitus. Chronic exposure to high glucose causes β-cell dysfunction and apoptosis in diabetes. Thorn grape (Vitis davidii Foex.) has been used to treat diabetes in Traditional Chinese medicine for many years. In our previous research, thorn grape seeds oil (TGSO) showed promising anti-diabetic effects in animal models. However, it is unknown whether TGSO played an anti-apoptotic role in the anti-diabetic effects and the mechanism regarding signal transduction pathway is unclear either. Methods The rattus pancreatic β-cell line RIN-m5F was treated with/without TGSO which was extracted by supercritical carbon dioxide (CO2) fluid extraction and analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). Cell apoptosis was detected by fluorescence activated cell sorting (FACS), insulin secretion was assayed by Enzyme-Linked Immunosorbent Assay (ELISA), and the apoptosis-related genes expressions were evaluated by quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Results TGSO, containing 87.02% unsaturated fatty acids (UFAs), significantly reduced pancreatic β-cell apoptosis and protected the insulin secretion impaired by high glucose. The expressions of pro-apoptotic genes such as iNOS, Caspase-3, ATF-3, JNK, p38 and Fas were down-regulated while the anti-apoptotic genes Akt and Bcl-2/Bax were up-regulated. Conclusions The results indicated that TGSO protected β-cells from high glucose-induced apoptosis and its protective activity may be linked to mitochondrial pathway, endoplasmic reticulum (ER) stress pathway and Fas signal pathway, which implied that TGSO might be an effective complementary or alternative medicine to reduce β-cell apoptosis and dysfunction.
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Compartmentalization of TNF-receptor 1 signaling: TNF-R1-associated caspase-8 mediates activation of acid sphingomyelinase in late endosomes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 691:605-16. [PMID: 21153367 DOI: 10.1007/978-1-4419-6612-4_64] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Apoptotic sphingolipid ceramide in cancer therapy. J Lipids 2011; 2011:565316. [PMID: 21490804 PMCID: PMC3066853 DOI: 10.1155/2011/565316] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/26/2010] [Indexed: 11/18/2022] Open
Abstract
Apoptosis, also called programmed cell death, is physiologically and pathologically involved in cellular homeostasis. Escape of apoptotic signaling is a critical strategy commonly used for cancer tumorigenesis. Ceramide, a derivative of sphingolipid breakdown products, acts as second messenger for multiple extracellular stimuli including growth factors, chemical agents, and environmental stresses, such as hypoxia, and heat stress as well as irradiation. Also, ceramide acts as tumor-suppressor lipid because a variety of stress stimuli cause apoptosis by increasing intracellular ceramide to initiate apoptotic signaling. Defects on ceramide generation and sphingolipid metabolism are developed for cancer cell survival and cancer therapy resistance. Alternatively, targeting ceramide metabolism to correct these defects might provide opportunities to overcome cancer therapy resistance.
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Caspase-8 and caspase-7 sequentially mediate proteolytic activation of acid sphingomyelinase in TNF-R1 receptosomes. EMBO J 2010; 30:379-94. [PMID: 21157428 DOI: 10.1038/emboj.2010.326] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 11/16/2010] [Indexed: 01/02/2023] Open
Abstract
We previously demonstrated that tumour necrosis factor (TNF)-induced ceramide production by endosomal acid sphingomyelinase (A-SMase) couples to apoptosis signalling via activation of cathepsin D and cleavage of Bid, resulting in caspase-9 and caspase-3 activation. The mechanism of TNF-mediated A-SMase activation within the endolysosomal compartment is poorly defined. Here, we show that TNF-induced A-SMase activation depends on functional caspase-8 and caspase-7 expression. The active forms of all three enzymes, caspase-8, caspase-7 and A-SMase, but not caspase-3, colocalize in internalized TNF receptosomes. While caspase-8 and caspase-3 are unable to induce activation of purified pro-A-SMase, we found that caspase-7 mediates A-SMase activation by direct interaction resulting in proteolytic cleavage of the 72-kDa pro-A-SMase zymogen at the non-canonical cleavage site after aspartate 253, generating an active 57 kDa A-SMase molecule. Caspase-7 down modulation revealed the functional link between caspase-7 and A-SMase, confirming proteolytic cleavage as one further mode of A-SMase activation. Our data suggest a signalling cascade within TNF receptosomes involving sequential activation of caspase-8 and caspase-7 for induction of A-SMase activation by proteolytic cleavage of pro-A-SMase.
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Föger N, Bulfone-Paus S, Chan AC, Lee KH. Subcellular compartmentalization of FADD as a new level of regulation in death receptor signaling. FEBS J 2009; 276:4256-65. [PMID: 19583773 DOI: 10.1111/j.1742-4658.2009.07134.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Fas-associated protein with death domain (FADD) is an essential adaptor protein in death receptor-mediated signal transduction. During apoptotic signaling, FADD functions in the cytoplasm, where it couples activated receptors with initiator caspase-8. However, in resting cells, FADD is predominantly stored in the nucleus. In this study, we examined the modalities of FADD intracellular trafficking. We demonstrate that, upon CD95 activation, FADD redistributes from the nucleus to the cytoplasm. This inducible nuclear-cytoplasmic translocation of FADD is independent of CD95 internalization, formation of the death-inducing signaling complex, and caspase-8 activation. In contrast to nuclear export of FADD, its subsequent recruitment and accumulation at endosomes containing internalized CD95 requires a caspase-8-dependent feedback loop. These data indicate the existence of differential pathways directing FADD nuclear export and cytoplasmic trafficking, and identify subcellular compartmentalization of FADD as a novel regulatory mechanism in death receptor signaling.
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Affiliation(s)
- Niko Föger
- Department of Immunology and Cell Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Germany
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Zhang Y, Li X, Becker KA, Gulbins E. Ceramide-enriched membrane domains--structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1788:178-83. [PMID: 18786504 DOI: 10.1016/j.bbamem.2008.07.030] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 07/28/2008] [Accepted: 07/29/2008] [Indexed: 12/28/2022]
Abstract
Membrane lipids seem to be organized and not randomly distributed in the cell membrane. In particular, sphingolipids seem to interact with cholesterol in the outer leaflet of the cell membrane resulting in the formation of distinct membrane domains, i.e. rafts. The generation of ceramide within rafts alters their biophysical properties and results in the formation of large ceramide-enriched membrane platforms. These platforms serve to cluster receptor molecules and to organize intracellular signalling molecules to facilitate signal transduction via a receptor upon stimulation. Thus, ceramide-enriched membrane domains amplify not only receptor-, but also stress-mediated signalling events. Although many receptors cluster, the molecular mechanisms mediating this important and general event in signal transduction need to be identified.
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Affiliation(s)
- Yang Zhang
- Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
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Ex vivo detection of primary leukemia cells resistant to granule cytotoxin-induced cell death: a rapid isolation method to study granzyme-B-mediated cell death. Ann Hematol 2008; 87:701-8. [PMID: 18437383 DOI: 10.1007/s00277-008-0485-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 03/10/2008] [Indexed: 10/22/2022]
Abstract
Cytotoxic T lymphocytes and natural killer cells (CTL/NK) induce cell death in leukemia cells by the granzyme B (grB)-dependent granule cytotoxin (GC) pathway. Resistance to GC may be involved in immune evasion of leukemia cells. The delivery of active grB into the cytoplasma is dependent on the presence of perforin (PFN) and grB complexes. We developed a rapid method for the isolation of GC to investigate GC-mediated cell death in primary leukemia cells. We isolated GC containing grB, grB complexes and PFN by detergent free hypotonic lysis of the human NK cell leukemia line YT. The GC induce grB-mediated, caspase-dependent apoptosis in live cells. The human leukemia cell lines KG-1, U937, K562 (myeloid leukemia), Jurkat, Daudi, and BV173 (lymphoblastic leukemia) treated with GC internalized grB and underwent cell death. In primary leukemia cells analyzed ex vivo, we found GC-resistant leukemia cells in three out of seven patients with acute myeloid leukemia and one out of six patients with acute lymphoblastic leukemia. We conclude that our method is fast (approximately 1 h) and yields active GC that induce grB-dependent cell death. Furthermore, resistance to GC can be observed in acute leukemias and may be an important mechanism contributing to leukemia cell immune evasion.
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Abstract
Sphingolipids (SLs) have been considered for many years as predominant building blocks of biological membranes with key structural functions and little relevance in cellular signaling. However, this view has changed dramatically in recent years with the recognition that certain SLs such as ceramide, sphingosine 1-phosphate and gangliosides, participate actively in signal transduction pathways, regulating many different cell functions such as proliferation, differentiation, adhesion and cell death. In particular, ceramide has attracted considerable attention in cell biology and biophysics due to its key role in the modulation of membrane physical properties, signaling and cell death regulation. This latter function is largely exerted by the ability of ceramide to activate the major pathways governing cell death such as the endoplasmic reticulum and mitochondria. Overall, the evidence so far indicates a key function of SLs in disease pathogenesis and hence their regulation may be of potential therapeutic relevance in different pathologies including liver diseases, neurodegeneration and cancer biology and therapy.
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Affiliation(s)
- Albert Morales
- Liver Unit and Centro de Investigaciones Biomédicas Esther Koplowitz, IMDiM, Hospital, Clínic i Provincial, Instituto Investigaciones Biomédicas August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
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Reinehr R, Sommerfeld A, Keitel V, Grether-Beck S, Häussinger D. Amplification of CD95 Activation by Caspase 8-induced Endosomal Acidification in Rat Hepatocytes. J Biol Chem 2008; 283:2211-22. [DOI: 10.1074/jbc.m706853200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Arboleda G, Waters C, Gibson R. Inhibition of caspases but not of calpains temporarily protect against C2-ceramide-induced death of CAD cells. Neurosci Lett 2007; 421:245-9. [PMID: 17573191 DOI: 10.1016/j.neulet.2007.05.032] [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: 03/15/2007] [Revised: 04/26/2007] [Accepted: 05/20/2007] [Indexed: 10/23/2022]
Abstract
Evidence has implicated apoptosis as a mechanism underlying cell death in diverse neurodegenerative diseases including Parkinson's disease (PD). Endogenous agents such as TNF-alpha, INF-gamma, IL-1beta and others stress signals activate the sphingomyelin pathway increasing ceramide levels. Ceramide triggers apoptotic pathways while inhibiting survival signalling, and is involved in the regulation of intracellular Ca(2+) homeostasis and compartmentalisation. The contribution of caspases in neuronal apoptosis has been highlighted by the increased survival exerted by caspase inhibition, but the involvement of calpains during neuronal apoptosis and the potential benefit of their inhibition is still controversial. In the present paper, we have analysed the contribution of caspases and calpains to cell death of CAD cells, a catecholaminergic cell line of mesencephalic origin, following C2-ceramide exposure. Ceramide caused CAD cell death by a dose and time dependant mechanism. 25microM of C2-ceramide caused apoptosis. Analysis of activation of caspases and calpains by differential cleavage of alpha-fodrin showed that although calpains are activated before caspases following C2-ceramide exposure, only caspase inhibition increased cell survival. These results demonstrate the activation of caspases and calpains in C2-ceramide-induced cell death, and support the role of caspase inhibition as a neuroprotective strategy and a plausible therapeutic approach to decrease catecholaminergic cell death.
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Affiliation(s)
- Gonzalo Arboleda
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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Grassmé H, Riethmüller J, Gulbins E. Biological aspects of ceramide-enriched membrane domains. Prog Lipid Res 2007; 46:161-70. [PMID: 17490747 DOI: 10.1016/j.plipres.2007.03.002] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 03/14/2007] [Accepted: 03/23/2007] [Indexed: 01/23/2023]
Abstract
Ceramide has been shown to be critically involved in many aspects of cellular responses to receptor-dependent and -independent stimuli. For instance, ceramide was demonstrated to be a central component of the signaling cascades mediating apoptosis after death receptor stimulation, treatment with chemotherapy or exposure to gamma-irradiation or UV-A light. Further studies indicated the importance of ceramide for the infection of mammalian cells with bacterial, viral and parasitic pathogens. Ceramide is released by the activity of acid, neutral or alkaline sphingomyelinases or de novo synthesized. A concept unifying the diverse biological functions of ceramide indicates that ceramide forms distinct membrane domains, named ceramide-enriched membrane domains or platforms. These domains serve the clustering of receptor molecules, the re-organization of signaling proteins, the exclusion of inhibitory signals and, thus, initiate and greatly amplify a primary signal. In addition, ceramide directly interacts with and stimulates intracellular enzymes that may act together with signals initiated in ceramide-enriched membrane domains to transmit signals into a cell.
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Affiliation(s)
- Heike Grassmé
- Institute of Molecular Biology, University of Duisburg-Essen, 45122 Essen, Germany
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19
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Simak J, Gelderman MP. Cell Membrane Microparticles in Blood and Blood Products: Potentially Pathogenic Agents and Diagnostic Markers. Transfus Med Rev 2006; 20:1-26. [PMID: 16373184 DOI: 10.1016/j.tmrv.2005.08.001] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cell membrane microparticles (MPs) circulate in the blood of healthy donors, and their elevated counts have been documented in various pathologies. Microparticles are phospholipid microvesicles of 0.05 to 1.5 microm in size, containing certain membrane proteins of their parental cells. Thus, different phenotypes of MPs derived from platelets, blood cells, endothelial cells, and some other cell types have been identified in plasma. Microparticles are released by various stimuli including shear stress, complement attack, or proapoptotic stimulation. Microparticle release is a highly controlled process and likely independent from metabolic energy. Elevated MPs in various diseases indicate their diagnostic importance, particularly in vascular pathologies. Moreover, MPs in blood possess a broad spectrum of biologic activities. Microparticles may facilitate cell-to-cell interactions, induce cell signaling, or even transfer receptors between different cell types. The physiological roles of MPs in various tissue defense processes have been suggested and the pathophysiologic implications of MPs in thrombosis, inflammation, cancer metastasis, or response to pathogens have been proposed. This is important for transfusion medicine because MPs are present in both plasma and cellular blood products. Thus, the investigation of potentially pathogenic effects of MPs in blood products and of MP release associated with blood product processing and storage have yet to come.
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Affiliation(s)
- Jan Simak
- Laboratory of Cellular Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA.
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20
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Hetz CA, Torres V, Quest AFG. Beyond apoptosis: nonapoptotic cell death in physiology and disease. Biochem Cell Biol 2005; 83:579-88. [PMID: 16234846 DOI: 10.1139/o05-065] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Apoptosis is a morphologically defined form of programmed cell death (PCD) that is mediated by the activation of members of the caspase family. Analysis of death-receptor signaling in lymphocytes has revealed that caspase-dependent signaling pathways are also linked to cell death by nonapoptotic mechanisms, indicating that apoptosis is not the only form of PCD. Under physiological and pathological conditions, cells demonstrate a high degree of flexibility in cell-death responses, as is reflected in the existence of a variety of mechanisms, including necrosis-like PCD, autophagy (or type II PCD), and accidental necrosis. In this review, we discuss recent data suggesting that canonical apoptotic pathways, including death-receptor signaling, control caspase-dependent and -independent cell-death pathways.Key words: apoptosis, necrosis, nonapoptotic programmed cell death, death receptors, ceramides.
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Affiliation(s)
- Claudio A Hetz
- Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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21
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Bollinger CR, Teichgräber V, Gulbins E. Ceramide-enriched membrane domains. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1746:284-94. [PMID: 16226325 DOI: 10.1016/j.bbamcr.2005.09.001] [Citation(s) in RCA: 256] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 09/05/2005] [Accepted: 09/06/2005] [Indexed: 01/05/2023]
Abstract
Cellular activation involves the re-organization of receptor molecules and the intracellular signalosom in the cell membrane. Recent studies indicate that specialized domains of the cell membrane, termed rafts, are central for the spatial organization of receptors and signaling molecules. Rafts are converted into larger membrane platforms by activity of the acid sphingomyelinase, which hydrolyses raft-sphingomyelin to ceramide. Ceramide molecules spontaneously associate to form ceramide-enriched microdomains, which fuse to large ceramide-enriched membrane platforms. The acid sphingomyelinase is activated by multiple stimuli including CD95, CD40, DR5/TRAIL, CD20, FcgammaRII, CD5, LFA-1, CD28, TNF, the Interleukin-1 receptor, the PAF-receptor, CD14, infection with P. aeruginosa, S. aureus, N. gonorrhoeae, Sindbis-Virus, Rhinovirus, treatment with gamma-irradiation, UV-light, doxorubicin, cisplatin, disruption of integrin-signaling and under some conditions of developmental death. Ceramide-enriched membrane platforms serve the clustering of receptors, the recruitment of intracellular signaling molecules and the exclusion of inhibitory signaling factors and, thus, facilitate signal transduction initiated by the specific stimulus.
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Affiliation(s)
- Claudia R Bollinger
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
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22
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Maloney M, Bishop S, Torrence G, DeLeon M. Comparison of Total Lipid Composition in Gb3‐Positive and Gb3‐Deficient Burkitt's Lymphoma Cells. J LIQ CHROMATOGR R T 2005. [DOI: 10.1080/10826070500189802] [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]
Affiliation(s)
- Mark Maloney
- a Department of Biology , Spelman College , Atlanta, Georgia, USA
| | - Shanita Bishop
- a Department of Biology , Spelman College , Atlanta, Georgia, USA
| | | | - Marisela DeLeon
- a Department of Biology , Spelman College , Atlanta, Georgia, USA
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23
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Rotolo JA, Zhang J, Donepudi M, Lee H, Fuks Z, Kolesnick R. Caspase-dependent and -independent Activation of Acid Sphingomyelinase Signaling. J Biol Chem 2005; 280:26425-34. [PMID: 15849201 DOI: 10.1074/jbc.m414569200] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent evidence suggests clustering of plasma membrane rafts into ceramide-enriched platforms serves as a transmembrane signaling mechanism for a subset of cell surface receptors and environmental stresses (Grassme, H., Jekle, A., Riehle, A., Schwarz, H., Berger, J., Sandhoff, K., Kolesnick, R., and Gulbins, E. (2001) J. Biol. Chem. 276, 20589-20596; Cremesti, A., Paris, F., Grassme, H., Holler, N., Tschopp, J., Fuks, Z., Gulbins, E., and Kolesnick, R. (2001) J. Biol. Chem. 276, 23954-23961). Translocation of the secretory form of acid sphingomyelinase (ASMase) into microscopic rafts generates therein the ceramide that drives raft coalescence. This process serves to feed forward Fas activation, with approximately 2% of full caspase 8 activation sufficient for maximal ASMase translocation, leading to death-inducing signaling complex formation within ceramide-rich platforms, and apoptosis. Here we report that treatment of Jurkat T cells with UV-C also induces ASMase translocation into rafts within 1 min, catalyzing sphingomyelin hydrolysis to ceramide and raft clustering. In contrast to Fas, UV-induced ASMase translocation and activation were caspase-independent. Nonetheless, ceramide-rich platforms promoted UV-C-induced death signaling, because ASMase inhibition or raft disruption inhibited apoptosis, improving clonogenic cell survival. These studies thus define two distinct mechanisms for biologically relevant ASMase activation within rafts; a Fas-mediated mechanism dependent upon caspase 8 and FADD, and a UV-induced mechanism independent of caspase activation. Consistent with this notion, genetic depletion or pharmacologic inhibition of caspase 8 or FADD, which render Jurkat cells incapable of sphingolipid signaling and apoptosis upon Fas ligation, did not impair these events upon UV-C stimulation.
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Affiliation(s)
- Jimmy A Rotolo
- Laboratory of Signal Transduction and Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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24
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Han X, Gross RW. Shotgun lipidomics: electrospray ionization mass spectrometric analysis and quantitation of cellular lipidomes directly from crude extracts of biological samples. MASS SPECTROMETRY REVIEWS 2005; 24:367-412. [PMID: 15389848 DOI: 10.1002/mas.20023] [Citation(s) in RCA: 879] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Lipidomics, after genomics and proteomics, is a newly and rapidly expanding research field that studies cellular lipidomes and the organizational hierarchy of lipid and protein constituents mediating life processes. Lipidomics is greatly facilitated by recent advances in, and novel applications of, electrospray ionization mass spectrometry (ESI/MS). In this review, we will focus on the advances in ESI/MS, which have facilitated the development of shotgun lipidomics and the utility of intrasource separation as an enabling strategy for utilization of 2D mass spectrometry in shotgun lipidomics of biological samples. The principles and experimental details of the intrasource separation approach will be extensively discussed. Other ESI/MS approaches towards the quantitative analyses of global cellular lipidomes directly from crude lipid extracts of biological samples will also be reviewed and compared. Multiple examples of lipidomic analyses from crude lipid extracts employing these approaches will be given to show the power of ESI/MS techniques in lipidomics. Currently, modern society is plagued by the sequelae of lipid-related diseases. It is our hope that the integration of these advances in multiple disciplines will catalyze the development of lipidomics, and such development will lead to improvements in diagnostics and therapeutics, which will ultimately result in the extended longevity and an improved quality of life for humankind.
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Affiliation(s)
- Xianlin Han
- Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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25
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Söderström TS, Nyberg SD, Eriksson JE. CD95 capping is ROCK-dependent and dispensable for apoptosis. J Cell Sci 2005; 118:2211-23. [PMID: 15855233 DOI: 10.1242/jcs.02343] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Upon engagement, the CD95 receptor is rapidly clustered into cellular 'caps'. This receptor capping is one of the first events to take place following activation and it has been proposed to be important for the initiation of apoptotic signaling. As the biological roles of CD95 capping are still elusive, we explored in detail the role of capping in induction of apoptosis in lymphocytes. CD95 capping was shown to be uncoupled from apoptosis, as apoptosis could occur in the absence of CD95 capping and, vice versa, capping could occur without inducing apoptosis. CD95 capping occurred concomitantly with reorganization of the actin cytoskeleton and aggregation of lipid rafts. While inhibition of actin polymerization and caspase-8 activity had cell type-specific effects on capping in type I and type II cells, the rapid CD95-mediated cellular polarization, as visualized by the orchestrated reorganization of CD95, F-actin and lipid rafts, was shown to be dependent on signaling by Rho kinase (ROCK) in both cell types, however, by distinct activation mechanisms in the respective cell type. CD95 activated RhoA exclusively in the type II cell, whereas ROCK activation was caspase-dependent in the type I cell. Taken together, our results imply that CD95 capping and the subsequent cellular polarization is a ROCK signaling-regulated process that does not correlate with the induction of apoptosis, but is more likely to be involved in the emerging non-apoptotic functions of CD95.
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26
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Morales A, Colell A, Mari M, Garcia-Ruiz C, Fernandez-Checa JC. Glycosphingolipids and mitochondria: role in apoptosis and disease. Glycoconj J 2005; 20:579-88. [PMID: 15454696 DOI: 10.1023/b:glyc.0000043294.62504.2c] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Glycosphingolipids (GSLs) comprise a class of lipids with important structural and signaling functions. Synthesized from ceramide in the Golgi, they are subsequently distributed to different compartments, most predominantly in the plasma membrane where they integrate signaling platforms. A recently characterized trafficking of ganglioside GD3 (GD3), a GSLs with two sialic-acid residues, to mitochondria has revealed a novel function of this lipid as a death effector. In addition to the interaction of GD3 with mitochondria recruiting these organelles to apoptotic pathways, GD3 disables survival paths dependent on NF-kappaB, thus favoring the balance towards cell death. The present review gathers the evidence documenting this emerging function of GSLs in cell death and their involvement in pathological states.
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Affiliation(s)
- Albert Morales
- Liver Unit, Instituto de Malalties Digestives, Hospital Clinic i Provincial, Instituto Investigaciones Biomédicas August Pi i Sunyer, Barcelona 08036, Spain
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27
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Hepatitis B virus mutations associated with fulminant hepatitis induce apoptosis in primary Tupaia hepatocytes. Hepatology 2005; 41:247-56. [PMID: 15660384 DOI: 10.1002/hep.20553] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hepatitis B virus (HBV) core promoter mutations have been implicated in the pathogenesis of fulminant hepatitis B. Due to the limited availability of primary human hepatocytes, the functional characterization of HBV mutants has been performed predominantly in transformed cells, which may not represent ideal model systems for studying virus-cell interactions. We and others have shown that primary hepatocytes of the tree shrew Tupaia belangeri support HBV infection and replication. In this study, we used primary Tupaia hepatocytes to analyze the phenotype of two HBV core promoter mutations that have been associated with a clinical outbreak of fatal fulminant hepatitis. Similar to previous findings in human hepatoma cells, the HBV core promoter mutations resulted in enhanced viral replication and core expression. Surprisingly, however, the presence of the mutations had a marked effect on hepatocyte viability not previously observed in hepatoma cells. Reduced cell viability was found to be due to the induction of apoptosis, as evidenced by caspase-3 activation and nuclear fragmentation. In conclusion, HBV mutants exhibit a novel phenotype in primary hepatocytes distinctly different from previous findings in hepatoma cell lines. This phenotype may have important implications for the understanding of the fulminant clinical course associated with HBV mutations.
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28
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Akundi RS, Candelario-Jalil E, Hess S, Hüll M, Lieb K, Gebicke-Haerter PJ, Fiebich BL. Signal transduction pathways regulating cyclooxygenase-2 in lipopolysaccharide-activated primary rat microglia. Glia 2005; 51:199-208. [PMID: 15800925 DOI: 10.1002/glia.20198] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Microglia are the major cell type involved in neuroinflammatory events in brain diseases such as encephalitis, stroke, and neurodegenerative disorders, and contribute significantly to the release of prostaglandins (PGs) during neuronal insults. In this report, we studied the immediate-early intracellular signalling pathways in microglia, following bacterial lipopolysaccharide (LPS) stimulation, leading to the synthesis and release of PGE2. Here we show that LPS induces cyclooxygenase (COX) 2 by activating sphingomyelinases leading to the release of ceramides, which in turn, activate the p38 mitogen-activated protein kinases (MAPK), but not the p42/44 MAPK. We further show that exogenously added ceramide analogue (C2-ceramide) also induce PGE2 synthesis through a p38 MAPK-dependent pathway. This potential nature of ceramides in activating microglia suggests that endogenously produced ceramides during neuronal apoptosis in ischemia or neurodegenerative diseases could also contribute to the amplification of neuroinflammatory events. In contrast to protein kinase C (PKC) and phosphocholine-specific phospholipase C (PC-PLC), which transcriptionally regulate LPS-induced COX-2 synthesis, inhibition of phospholipase A2 (PLA2) has no effect on COX-2 transcription, although it inhibits the release of PGE2. Transcriptional regulation of LPS-induced COX-2 by PKC is further proved by the ability of the PKC inhibitor, Gö 6976, to inhibit LPS-induced 8-isoprostane synthesis, but not affecting LPS-induced COX-2 activity. Our data with 8-isoprostane also indicates that COX-2 plays a major role in ROS production in LPS-activated microglia. This detailed view of the intracellular signaling pathway in microglial activation and COX-2 expression opens a new therapeutic window in the search for new and more effective central anti-inflammatory agents.
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Affiliation(s)
- Ravi Shankar Akundi
- Department of Psychiatry, University of Freiburg Medical School, Freiburg, Germany
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29
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Marchesini N, Hannun YA. Acid and neutral sphingomyelinases: roles and mechanisms of regulation. Biochem Cell Biol 2004; 82:27-44. [PMID: 15052326 DOI: 10.1139/o03-091] [Citation(s) in RCA: 259] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Ceramide, an emerging bioactive lipid and second messenger, is mainly generated by hydrolysis of sphingomyelin through the action of sphingomyelinases. At least two sphingomyelinases, neutral and acid sphingomyelinases, are activated in response to many extracellular stimuli. Despite extensive studies, the precise cellular function of each of these sphingomyelinases in sphingomyelin turnover and in the regulation of ceramide-mediated responses is not well understood. Therefore, it is essential to elucidate the factors and mechanisms that control the activation of acid and neutral sphingomyelinases to understand their the roles in cell regulation. This review will focus on the molecular mechanisms that regulate these enzymes in vivo and in vitro, especially the roles of oxidants (glutathione, peroxide, nitric oxide), proteins (saposin, caveolin 1, caspases), and lipids (diacylglycerol, arachidonic acid, and ceramide).
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Affiliation(s)
- Norma Marchesini
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, 29425, USA
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30
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Lépine S, Lakatos B, Courageot MP, Le Stunff H, Sulpice JC, Giraud F. Sphingosine Contributes to Glucocorticoid-Induced Apoptosis of Thymocytes Independently of the Mitochondrial Pathway. THE JOURNAL OF IMMUNOLOGY 2004; 173:3783-90. [PMID: 15356125 DOI: 10.4049/jimmunol.173.6.3783] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
During the selection process in the thymus, most thymocytes are eliminated by apoptosis through signaling via TCR or glucocorticoids. The involvement of ceramide (Cer) and sphingosine (SP), important apoptotic mediators, remains poorly defined in glucocorticoid-induced apoptosis. We report that, in mouse thymocytes, apoptosis triggered by 10(-6) M dexamethasone (DX) was preceded by a caspase-dependent Cer and SP generation, together with activation of acidic and neutral ceramidases. Apoptosis was drastically reduced by blocking either sphingolipid production (by acid sphingomyelinase inhibitor) or SP production (by ceramidase inhibitors), but not by inhibition of de novo Cer synthesis. Thus, SP generated through acid sphingomyelinase and ceramidase activity would contribute to the apoptotic effect of DX. Consistent with this hypothesis, SP addition or inhibition of SP kinase induced thymocyte apoptosis. DX induced a proteasome-dependent loss of mitochondrial membrane potential (Deltapsim) and caspase-8, -3, and -9 processing. Apoptosis was abolished by inhibition of Deltapsim loss or caspase-8 or -3, but not caspase-9. Deltapsim loss was independent of SP production and caspase-8, -3, and -9 activation. However, inhibition of SP production reduced caspase-8 and -3, but not caspase-9 processing. Proteasome inhibition impaired activation of the three caspases, whereas inhibition of Deltapsim loss solely blocked caspase-9 activation. These data indicate that DX-induced apoptosis is mediated in part by SP, which contributes, together with proteasome activity, to caspase-8-3 processing independently of mitochondria, and in part by the proteasome/mitochondria pathway, although independently of caspase-9 activation.
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Affiliation(s)
- Sandrine Lépine
- Biomembranes et Messagers Cellulaires, Centre National de la Recherche Scientifique, Université Paris XI, Orsay, France
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31
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Huang ST, Yang RC, Chen MY, Pang JHS. Phyllanthus urinaria induces the Fas receptor/ligand expression and ceramide-mediated apoptosis in HL-60 cells. Life Sci 2004; 75:339-51. [PMID: 15135654 DOI: 10.1016/j.lfs.2003.12.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2003] [Accepted: 12/20/2003] [Indexed: 11/21/2022]
Abstract
Phyllanthus urinaria (P. urinaria), a widely used herb medicine, was tested for the anticancer effect on human myeloid leukemia cells in this study. The water extract of P. urinaria induced the apoptosis of HL-60 cells as demonstrated by morphological change, DNA fragmentation and increased caspase-3 activity. However, normal human peripheral mononuclear cells remained viable under the same treatment. The P. urinaria-induced apoptosis of HL-60 cells was associated with the increased Bax gene expression and decreased Bcl-2 gene expression. In addition, the gene expressions of Fas receptor and Fas ligand, but not p53, were also induced in HL-60 cells dose- and time-dependently. The inhibitor of ceramide synthase, fumonisin B1, completely suppressed the apoptosis induced by P. urinaria and this inhibitory effect of fumonisin B1 could be eliminated by the addition of ceramide. It indicated that the activity of ceramide synthase is critical for the P. urinaria-induced apoptosis in HL-60 cells. The P. urinaria-induced apoptosis in HL-60 cells is mediated through a ceramide-related pathway.
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Affiliation(s)
- Sheng-Teng Huang
- Chinese Herbal Pharmacy, Chang Gung Memorial Hospital, Tao-Yuan, Taiwan, ROC
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32
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Testai FD, Landek MA, Goswami R, Ahmed M, Dawson G. Acid sphingomyelinase and inhibition by phosphate ion: role of inhibition by phosphatidyl-myo-inositol 3,4,5-triphosphate in oligodendrocyte cell signaling. J Neurochem 2004; 89:636-44. [PMID: 15086520 DOI: 10.1046/j.1471-4159.2004.02374.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
There is ample evidence that both acid (ASMase) and neutral (NSMase) sphingomyelinases play a role in cell death so inhibitors of either enzyme could have significant value as protectors against neurodegeneration. We used a fluorogenic sphingomyelinase substrate, 6-hexadecanoylamino-4-methylumbelliferyl-phosphorylcholine, and a [(14)C]choline-labeled sphingomyelin substrate to screen large numbers of phosphocompounds for inhibition of ASMase in extracts of human oligodendroglioma cells (HOG) and neonatal rat oligodendrocytes. Non-competitive inhibition was observed with inorganic phosphate and AMP, which was a more potent inhibitor of ASMase than cyclic AMP, ADP or ATP. However, other nucleotide phosphates, sugar phosphates, nucleotide sugars and glycerol phosphate did not inhibit ASMase. Our key finding was that phosphatidyl-myo-inositol 3,4,5-triphosphate [PtdIns (3,4,5)P(3)] was a much more potent inhibitor of ASMase than lysophosphatidic acid or phosphatidyl-myo-inositol 4,5-diphosphate [PtdIns(4,5)P(2)]. When PtdIns(3,4,5)P(3) was added to cultured cells we observed 50% inhibition of ASMase but no inhibition of other lysosomal hydrolases. After transfection of HOG cells with the tumor supressor phosphatase and tensin homolog protein (PTEN), which hydrolyses PtdIns(3,4,5)P(3) to PtdIns(4,5)P(2), we observed a two-fold increase in ASMase activity. Furthermore, the phosphatidylinositol-3-kinase inhibitor wortmannin (which reduces PtdIns(3,4,5)P(3) levels) also resulted in activation of ASMase. We propose that the small amount of ASMase activity associated with detergent-resistant cell membranes (Rafts) is regulated by PtdIns(3,4,5)P(3) and is most likely involved in receptor clustering and capping.
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Affiliation(s)
- F D Testai
- Department of Pediatrics, University of Chicago, Chicago, Illinois, USA
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33
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Marí M, Colell A, Morales A, Pañeda C, Varela-Nieto I, García-Ruiz C, Fernández-Checa JC. Acidic sphingomyelinase downregulates the liver-specific methionine adenosyltransferase 1A, contributing to tumor necrosis factor-induced lethal hepatitis. J Clin Invest 2004; 113:895-904. [PMID: 15067322 PMCID: PMC362116 DOI: 10.1172/jci19852] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Accepted: 01/13/2004] [Indexed: 12/23/2022] Open
Abstract
S-adenosyl-L-methionine (SAM) is synthesized by methionine adenosyltransferases (MATs). Ablation of the liver-specific MAT1A gene results in liver neoplasia and sensitivity to oxidant injury. Here we show that acidic sphingomyelinase (ASMase) mediates the downregulation of MAT1A by TNF-alpha. The levels of MAT1A mRNA as well as MAT I/III protein decreased in cultured rat hepatocytes by in situ generation of ceramide from exogenous human placenta ASMase. Hepatocytes lacking the ASMase gene (ASMase-/-) were insensitive to TNF-alpha but were responsive to exogenous ASMase-induced downregulation of MAT1A. In an in vivo model of lethal hepatitis by TNF-alpha, depletion of SAM preceded activation of caspases 8 and 3, massive liver damage, and death of the mice. In contrast, minimal hepatic SAM depletion, caspase activation, and liver damage were seen in ASMase-/- mice. Moreover, therapeutic treatment with SAM abrogated caspase activation and liver injury, thus rescuing ASMase+/+ mice from TNF-alpha-induced lethality. Thus, we have demonstrated a new role for ASMase in TNF-alpha-induced liver failure through downregulation of MAT1A, and maintenance of SAM may be useful in the treatment of acute and chronic liver diseases.
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Affiliation(s)
- Montserrat Marí
- Liver Unit, Institut de Malalties Digestives, Hospital Clínic i Provincial, Instituto Investigaciones Biomédicas August Pi i Sunyer, Barcelona, Spain
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Marí M, Colell A, Morales A, Pañeda C, Varela-Nieto I, García-Ruiz C, Fernández-Checa JC. Acidic sphingomyelinase downregulates the liver-specific methionine adenosyltransferase 1A, contributing to tumor necrosis factor–induced lethal hepatitis. J Clin Invest 2004. [DOI: 10.1172/jci200419852] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Testai FD, Landek MA, Dawson G. Regulation of sphingomyelinases in cells of the oligodendrocyte lineage. J Neurosci Res 2004; 75:66-74. [PMID: 14689449 DOI: 10.1002/jnr.10816] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Controversy exists regarding the nature of the "executioner" sphingomyelinase (SMase) in cells and its subcellular localization. A new fluorescence-based assay with the substrate 6-hexadecanoylamino-4-methylumbelliferyl-phosphorylcholine allowed rapid and reliable microassays of neutral (N) and acid (A) SMase activity in cell extracts from primary cultures of neonatal rat oligodendrocytes (OPC) and a human oligodendroglioma cell line (HOG). Total SMase activity was much higher in OPC than in HOG cells. Both staurosporine and tumor necrosis factor-alpha (TNF-alpha) induced apoptosis and activated NSMase in a multiphasic manner in both OPC and HOG cells. The increase in caspase 8 activity preceded the 1 hr peak of NSMase activation, which was followed by caspase 3 activation. In contrast, ASMase activity, which constituted >90% of the total SMase activity, was unresponsive to proapoptotic drugs. Neither reducing ASMase levels by 50% by pretreatment with desipramine nor inhibiting sphingolipid synthesis by 50% with fumonisin B1 had any effect on cell death. Isolation of sphingolipid-rich plasma membrane microdomains (rafts) from the cells by sucrose density gradient ultracentrifugation revealed an enrichment of sphingomyelin, ceramide, and caspase 8. Proapoptotic drugs such as staurosporine promoted the translocation of NSMase to the raft fraction. In contrast, ASMase, other lysosomal hydrolases, and caspase 3 remained absent from rafts even after staurosporine treatment. The staurosporine-induced concomitant increase of ceramide in the raft fraction and caspase 3 in the cytosol could be mimicked by the addition of exogenous bacterial SMase. We conclude that caspase 8 activates NSMase in rafts in oligodendrocytes and that the downstream apoptotic signal is via caspase 3.
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Affiliation(s)
- F D Testai
- Departments of Pediatrics, Biochemistry, and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA
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Abstract
Apoptosis, also known as programmed cell death, is the major type of cell death involved in normal development, regeneration, proliferation and pathologic degeneration in the central nervous system (CNS). The apoptotic process can be divided further into two pathways depending on the involvement of mitochondria and related biochemical cascades. The internal pathway of apoptosis is initiated by a variety of cytotoxic stimuli and mediated by the release of cytochrome c and subsequent activation of downstream caspases. The external pathway is mainly triggered by ligation of death receptors such as Fas, tumor necrosis factor (TNF)-related apoptosis inducing ligand-R1 (TRAIL-R1), TRAIL-R2 and TNFRp55, and mediated by direct activation of upstream caspases. The Fas-FasL system has been known as a prototypic inducer of extrinsic cell death responsible for cell-mediated cytotoxicity, peripheral immune regulation, immune privilege and "counterattack" of malignant tumor cells against the host immune system. Fas and FasL are expressed in the normal CNS, and expression increases in inflamed and degenerated brains. Like other specialized tissues such as the eye and testis, the Fas-FasL system is thought to be involved in immune suppressed status in the CNS. Expression of Fas and FasL is significantly elevated in a variety of the neurologic disorders, suggesting the possibility that this system may play roles in degenerative and inflammatory responses in the CNS. Therefore, the FasL-Fas system should be considered as a double-edged sword in the CNS: maintaining the immune suppressed status in normal brain and inducing neuronal cell death and inflammation in a variety of neurologic disorders.
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Affiliation(s)
- Chulhee Choi
- The Center for Cell Signaling Research and Division of Molecular Life Sciences, Ewha Womans University, 11-1 Daehyun-dong, Sudaemun-gu, Seoul 120-750, South Korea.
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Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a clinically useful cytokine. TRAIL induces apoptosis in a wide variety of transformed cells, but does not cause toxicity to most normal cells. Recent studies show that death receptors (DR4 and DR5), decoy receptors (DcR1 and DcR2), and death inhibitors (FLIP, FAP-1, and IAP) are responsible for the differential sensitivity to TRAIL of normal and tumor cells. Several researchers have also shown that genotoxic agents, such as chemotherapeutic agents and ionizing radiation, enhance TRAIL-induced cytotoxicity by increasing DR5 gene expression or decreasing the intracellular level of FLIP, an antiapoptotic protein. Previous studies have shown that ceramide helps to regulate a cell's response to various forms of stress. Stress-induced alterations in the intracellular concentration of ceramide occur through the activation of a variety of enzymes that synthesize or catabolize ceramide. Increases in intracellular ceramide levels modulate apoptosis by acting through key proteases, phosphatases, and kinases. This review discusses the interaction between TRAIL and ceramide signaling pathways in regulating apoptotic death.
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Affiliation(s)
- Yong J Lee
- Department of Surgery and Pharmacology, University of Pittsburgh, Pennsylvania 15213, USA
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Grassmé H, Cremesti A, Kolesnick R, Gulbins E. Ceramide-mediated clustering is required for CD95-DISC formation. Oncogene 2003; 22:5457-70. [PMID: 12934106 DOI: 10.1038/sj.onc.1206540] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Early events required for induction of apoptosis by CD95 are preassociation of CD95, the formation of the death-inducing signaling complex (DISC) and clustering of CD95 in distinct membrane domains. Here, we identify the molecular ordering of these events and show that the acid sphingomyelinase (ASM) functions upstream of the DISC to mediate CD95 clustering in ceramide-enriched membrane platforms, an event that is required for DISC formation. Experiments in ASM-deficient cells revealed that CD95 ligation, in the absence of ceramide generation, triggers <1% of full caspase 8 activation at the receptor. This event, however, is both necessary and sufficient to trigger translocation of ASM onto the outer leaflet of the plasma membrane, ASM activation and ceramide release, but insufficient for apoptosis induction. Ceramide-mediated CD95 clustering then amplifies the primary CD95 signaling and drives the second step of CD95 signaling, that is, formation of the DISC yielding 100% caspase activity and apoptosis. These studies suggest that the most parsimonious interpretation of the molecular ordering of the earliest events in CD95 signaling, at least in some cells, is: CD95 ligation-->1% of maximum caspase 8 activation-->ASM translocation-->ceramide generation-->CD95 clustering-->DISC formation-->100% of maximum caspase 8 activation-->apoptosis.
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Affiliation(s)
- Heike Grassmé
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
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Broxterman HJ, Lankelma J, Hoekman K. Resistance to cytotoxic and anti-angiogenic anticancer agents: similarities and differences. Drug Resist Updat 2003; 6:111-27. [PMID: 12860459 DOI: 10.1016/s1368-7646(03)00026-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Intrinsic resistance to anticancer drugs, or resistance developed during chemotherapy, remains a major obstacle to successful treatment. This is the case both for resistance to cytotoxic agents, directed at malignant cells, and for resistance to anti-angiogenic agents, directed at non-malignant endothelial cells. In this review, we will discuss mechanisms of resistance which have a bearing on both these conceptually different classes of drugs. The complexity of drug resistance, involving drug transporters, such as P-glycoprotein, as well as resistance related to the tissue structure of solid tumors and its consequences for drug delivery is discussed. Possible mechanisms of resistance to endothelial cell-targeted drugs, including inhibitors of the VEGF receptor and EGF receptor family, are reviewed. The resistance of cancer cells as well as endothelial cells related to anti-apoptotic signaling events initiated by cell integrin-matrix interactions is discussed. Current strategies to overcome resistance mechanisms are summarized; they include high-dose chemotherapy, tumor targeting of cytotoxics to improve tumor uptake, low-dose protracted (metronomic) chemotherapy and combinations of classical agents with anti-angiogenic agents. This review discusses primarily literature published in 2001 and 2002.
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Affiliation(s)
- Henk J Broxterman
- Department of Medical Oncology, VU University Medical Center, BR 232, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
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40
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Abstract
Apoptosis can be regulated at multiple levels. A number of proteins with regulatory function in cell death are sensitive to cellular redox environment. The antioxidant glutathione (GSH) and redox-sensitive proteins, thioredoxin and glutathione S-transferase, thus regulate cell death pathways by modulating the redox state of specific thiol residues of target proteins including stress kinases, transcription factors, and caspases. GSH in mitochondria plays an important role in the integrity of mitochondrial proteins and lipids known to play a vital role in the permeabilization of mitochondrial membranes and release of proapoptotic factors. The regulation of mitochondrial GSH (mGSH) is determined by its uptake from the cytosol which is dependent on appropriate membrane dynamics. The deposition of cholesterol in mitochondria induced by alcohol intake impairs this translocation, resulting in severe depletion of mGSH and in sensitization to apoptosis stimuli. Although the interaction of proapoptotic proteins with mitochondria initiates apoptotic pathways, recent data indicate that the mitochondrial trafficking of glycosphingolipids, e.g., ganglioside GD3, induced by apoptotic stimuli is a key event that sets off mitochondrial-dependent apoptotic cascades.
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Affiliation(s)
- José C Fernández-Checa
- Liver Unit, Instituto Malalties Digestives, Hospital Clinic i Provincial, Instituto Investigaciones Biomedicas August Pi I Sunyer, Consejo Superior Investigaciones Científicas, 08036 Barcelona, Spain.
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Kilkus J, Goswami R, Testai FD, Dawson G. Ceramide in rafts (detergent-insoluble fraction) mediates cell death in neurotumor cell lines. J Neurosci Res 2003; 72:65-75. [PMID: 12645080 DOI: 10.1002/jnr.10549] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Detergent-resistant lipid microdomains (Rafts) were isolated from human oligodendroglioma (HOG), human neuroblastoma (LA-N-5), and immortalized dorsal root ganglion (F-11) cell lines by sucrose-density gradient ultracentrifugation and shown to be enriched in cholesterol, sphingomyelin, and ceramide. [(3)H]palmitate labeling allowed the Raft fraction to be easily identified as a sharp peak of (3)H radioactivity in the 5-30% sucrose interphase. Treatment of [(3)H]palmitate-labeled cells with staurosporine (to activate caspase 8 and induce apoptosis) or exogenous sphingomyelinase specifically increased the [(3)H]ceramide content of the Raft fraction. Depletion of cholesterol with beta-methylcyclodextran decreased Raft formation and partially blocked staurosporine-induced apoptosis. Similarly, treatment of cells with Fumonisin B1 to inhibit de novo sphingolipid synthesis by 50% reduced the labeling of the Raft fraction and partially blocked staurosporine-induced apoptosis. Staurosporine treatment activated neutral sphingomyelinase but had no effect on acid sphingomyelinase activity or on other lysosomal hydrolases, such as alpha-L-fucosidase. Most of the neutral sphingomyelinase activity is in the Raft fraction, suggesting that the conversion of sphingomyelin to ceramide in Rafts is an important event in neural cell apoptosis.
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Affiliation(s)
- John Kilkus
- Departments of Pediatrics, Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 30637, USA
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Frago LM, Cañón S, de la Rosa EJ, León Y, Varela-Nieto I. Programmed cell death in the developing inner ear is balanced by nerve growth factor and insulin-like growth factor I. J Cell Sci 2003; 116:475-86. [PMID: 12508109 DOI: 10.1242/jcs.00223] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nerve growth factor induces cell death in organotypic cultures of otic vesicle explants. This cell death has a restricted pattern that reproduces the in vivo pattern of apoptosis occurring during inner ear development. In this study, we show that binding of nerve growth factor to its low affinity p75 neurotrophin receptor is essential to achieve the apoptotic response. Blockage of binding to p75 receptor neutralized nerve-growth-factor-induced cell death, as measured by immunoassays detecting the presence of cytosolic oligonucleosomes and by TUNEL assay to visualize DNA fragmentation. Nerve growth factor also induced a number of cell-death-related intracellular events including ceramide generation, caspase activation and poly-(ADP ribose) polymerase cleavage. Again, p75 receptor blockade completely abolished all of these effects. Concerning the intracellular pathway, ceramide increase depended on initiator caspases, whereas its actions depended on both initiator and effector caspases, as shown by using site-specific caspase inhibitors. Conversely, insulin-like growth factor I, which promotes cell growth and survival in the inner ear, abolished apoptosis induced by nerve growth factor. Insulin-like growth factor cytoprotective actions were accomplished, at least in part, by decreasing endogenous ceramide levels and activating Akt. Taken together, these results strongly suggest that regulation of nerve-growth-factor-induced apoptosis in the otocysts occurs via p75 receptor binding and is strictly controlled by the interaction with survival signalling pathways.
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Affiliation(s)
- Laura M Frago
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain
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García-Ruiz C, Colell A, Marí M, Morales A, Calvo M, Enrich C, Fernández-Checa JC. Defective TNF-alpha-mediated hepatocellular apoptosis and liver damage in acidic sphingomyelinase knockout mice. J Clin Invest 2003; 111:197-208. [PMID: 12531875 PMCID: PMC151862 DOI: 10.1172/jci16010] [Citation(s) in RCA: 171] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This study addressed the contribution of acidic sphingomyelinase (ASMase) in TNF-alpha-mediated hepatocellular apoptosis. Cultured hepatocytes depleted of mitochondrial glutathione (mGSH) became sensitive to TNF-alpha, undergoing a time-dependent apoptotic cell death preceded by mitochondrial membrane depolarization, cytochrome c release, and caspase activation. Cyclosporin A treatment rescued mGSH-depleted hepatocytes from TNF-alpha-induced cell death. In contrast, mGSH-depleted hepatocytes deficient in ASMase were resistant to TNF-alpha-mediated cell death but sensitive to exogenous ASMase. Furthermore, although in vivo administration of TNF-alpha or LPS to galactosamine-pretreated ASMase(+/+) mice caused liver damage, ASMase(-/-) mice exhibited minimal hepatocellular injury. To analyze the requirement of ASMase, we assessed the effect of glucosylceramide synthetase inhibition on TNF-alpha-mediated apoptosis. This approach, which blunted glycosphingolipid generation by TNF-alpha, protected mGSH-depleted ASMase(+/+) hepatocytes from TNF-alpha despite enhancement of TNF-alpha-stimulated ceramide formation. To further test the involvement of glycosphingolipids, we focused on ganglioside GD3 (GD3) because of its emerging role in apoptosis through interaction with mitochondria. Analysis of the cellular redistribution of GD3 by laser scanning confocal microscopy revealed the targeting of GD3 to mitochondria in ASMase(+/+) but not in ASMase(-/-) hepatocytes. However, treatment of ASMase(-/-) hepatocytes with exogenous ASMase induced the colocalization of GD3 and mitochondria. Thus, ASMase contributes to TNF-alpha-induced hepatocellular apoptosis by promoting the mitochondrial targeting of glycosphingolipids.
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Affiliation(s)
- Carmen García-Ruiz
- Liver Unit, Instituto de Malalties Digestives, Hospital Clinic i Provincial, Instituto de Investigaciones Biomédicas August Pi Suñer, Barcelona, Spain
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Pettus BJ, Bielawska A, Kroesen BJ, Moeller PDR, Szulc ZM, Hannun YA, Busman M. Observation of different ceramide species from crude cellular extracts by normal-phase high-performance liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2003; 17:1203-1211. [PMID: 12772277 DOI: 10.1002/rcm.1043] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Normal-phase high-performance liquid chromatography (NP-HPLC) coupled to atmospheric pressure chemical ionization mass spectrometry (APCI-MS) allows qualitative analysis of endogenous ceramide and dihydroceramide species from crude lipid extracts utilizing chromatographic methods readily adaptable from commonly used thin layer chromatography (TLC) conditions. Qualitative information for the species comes from observation of differences in chromatographic and mass spectrometric behavior between species. Application to the analysis of ceramide and dihydroceramide from various cell lines is demonstrated. The results show the species profile in each cell line to be unique despite growth under identical conditions. The results from APCI-MS analysis corroborate and enhance information acquired from use of the diacylglycerol kinase assay for total ceramide measurement. This technique readily allows the previously difficult distinction between ceramide and dihydroceramide species.
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Affiliation(s)
- Benjamin J Pettus
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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Pettus BJ, Chalfant CE, Hannun YA. Ceramide in apoptosis: an overview and current perspectives. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1585:114-25. [PMID: 12531544 DOI: 10.1016/s1388-1981(02)00331-1] [Citation(s) in RCA: 579] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Recent years have witnessed significant advances in the understanding of the role of ceramide in apoptosis. This review summarizes these recent findings and discusses insights from studies of ceramide metabolism, topology, and effector actions. The recent identification of several genes for enzymes of ceramide metabolism, the development of mass spectrometric methods for ceramide analysis, and the increasing molecular and pharmacological tools to probe ceramide metabolism and function promise an accelerated phase in defining the molecular and biochemical details of the role of ceramide in apoptosis.
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Affiliation(s)
- Benjamin J Pettus
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
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Abstract
Acid sphingomyelinase (ASM) has been shown to be activated by a variety of receptor molecules and stimuli including CD95, the tumor necrosis factor receptor (TNF-R), CD40, CD28, LFA-1, CD5, during development, irradiation, heat shock, UV light or bacterial and viral infections. The central role of ASM-released ceramide in the response to those stimuli is confirmed by several genetic studies. ASM and ceramide might mediate their biological effects by the activation of several intracellular signaling molecules including cathepsin D, phospholipase A(2) or the kinase suppressor of Ras. In addition, recent fluorescence microscopy studies indicate that distinct, small membrane domains, termed rafts, are modified by ceramide to form larger domains, which serve to cluster receptor molecules. The generation of a high receptor density might be required for initiation of receptor-specific signaling and explain the function of the ASM and ceramide in multiple signaling pathways.
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Affiliation(s)
- Erich Gulbins
- Department of Molecular Biology, University of Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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Erdreich-Epstein A, Tran LB, Bowman NN, Wang H, Cabot MC, Durden DL, Vlckova J, Reynolds CP, Stins MF, Groshen S, Millard M. Ceramide signaling in fenretinide-induced endothelial cell apoptosis. J Biol Chem 2002; 277:49531-7. [PMID: 12388538 DOI: 10.1074/jbc.m209962200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Stress stimuli can mediate apoptosis by generation of the lipid second messenger, ceramide. Herein we investigate the molecular mechanism of ceramide signaling in endothelial apoptosis induced by fenretinide (N-(4-hydroxyphenyl)retinamide (4-HPR)). 4-HPR, a synthetic derivative of retinoic acid that induces ceramide in tumor cell lines, has been shown to have antiangiogenic effects, but the molecular mechanism of these is largely unknown. We report that 4-HPR was cytotoxic to endothelial cells (50% cytotoxicity at 2.4 microm, 90% at 5.36 microm) and induced a caspase-dependent endothelial apoptosis. 4-HPR (5 microm) increased ceramide levels in endothelial cells 5.3-fold, and the increase in ceramide was required to achieve the apoptotic effect of 4-HPR. The 4-HPR-induced increase in ceramide was suppressed by inhibitors of ceramide synthesis, fumonisin B(1), myriocin, and l-cycloserine, and 4-HPR transiently activated serine palmitoyltransferase, demonstrating that 4-HPR induced de novo ceramide synthesis. Sphingomyelin levels were not altered by 4-HPR, and desipramine had no effect on ceramide level, suggesting that sphingomyelinase did not contribute to the 4-HPR-induced ceramide increase. Finally, the pancaspase inhibitor, t-butyloxycarbonyl-aspartyl[O-methyl]-fluoromethyl ketone, suppressed 4-HPR-mediated apoptosis but not ceramide accumulation, suggesting that ceramide is upstream of caspases. Our results provide the first evidence that increased ceramide biosynthesis is required for 4-HPR-induced endothelial apoptosis and present a molecular mechanism for its antiangiogenic effects.
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Affiliation(s)
- Anat Erdreich-Epstein
- Division of Hematology-Oncology, Department of Pediatrics, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA.
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García-Ruiz C, Colell A, Morales A, Calvo M, Enrich C, Fernández-Checa JC. Trafficking of ganglioside GD3 to mitochondria by tumor necrosis factor-alpha. J Biol Chem 2002; 277:36443-8. [PMID: 12118012 DOI: 10.1074/jbc.m206021200] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The interaction of mitochondria with proapoptotic proteins activates apoptosis pathways. Previous findings have identified ganglioside GD3 (GD3) as an emerging apoptotic lipid intermediate that targets mitochondria in response to death signals. Using immunoelectron and laser scanning confocal microscopy, we characterize the trafficking of GD3 to mitochondria in response to tumor necrosis factor-alpha (TNF-alpha) in rat hepatocytes. In control hepatocytes, GD3 is present predominantly at the plasma membrane as well as in the endosomal/Golgi network, as verified by its colocalization with the asialoglycoprotein receptor. Following TNF-alpha exposure, GD3 undergoes a rapid cellular redistribution with a gradual loss from the plasma membrane before its colocalization with mitochondria. This process is mimicked by acidic sphingomyelinase and ionizing radiation but not by neutral sphingomyelinase or staurosporin. TNF-alpha stimulated the colocalization of GD3 with early and late endosomal markers, Rab 5 and Rab 7, whereas perturbation of plasma membrane cholesterol or actin cytoskeleton or inhibition of glucosylceramide synthase prevented the trafficking of GD3 to mitochondria. Finally, prevention of the TNF-alpha-stimulated neosynthesis of GD3, cyclosporin A, and latrunculin A or filipin protected sensitized hepatocytes from TNF-alpha-mediated cell death. Thus, the intracellular redistribution and mitochondrial targeting of GD3 during TNF-alpha signaling occurs through actin cytoskeleton vesicular trafficking and contributes to TNF-alpha-mediated hepatocellular cell death.
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Affiliation(s)
- Carmen García-Ruiz
- Liver Unit, Instituto de Malalties Digestives, Hospital Clinic i Provincial, Barcelona, 08036, Spain
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49
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Affiliation(s)
- Erich Gulbins
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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50
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Šimák J, Holada K, Vostal JG. Release of annexin V-binding membrane microparticles from cultured human umbilical vein endothelial cells after treatment with camptothecin. BMC Cell Biol 2002; 3:11. [PMID: 12052248 PMCID: PMC116580 DOI: 10.1186/1471-2121-3-11] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2002] [Accepted: 05/28/2002] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Elevated plasma counts of endothelial microparticles (MP) have been demonstrated in various diseases with a vascular injury component. We used flow cytometry to study the MP-release from cultured human umbilical vein endothelial cells (HUVEC) stimulated by various agonists. MP-release by a topoisomerase I inhibitor camptothecin has been studied in detail. RESULTS Overnight stimulation of HUVEC with either LPS or TNFalpha, or 30 min stimulation with thrombin, phorbol-myristate-acetate, tissue plasminogen activator, or angiotensin-II did not cause a significant release of annexin V-binding MP. In contrast, induction of apoptosis with 5 microM camptothecin, documented by 60-70% desquamation of HUVEC culture, annexin V-binding to the cells and DNA-fragmentation, led to a release of annexin V-binding microparticles (approximately 80,000 MP/103 cells). This microparticle-release was prevented by Z-Val-Ala-Asp-fluoromethyl-ketone (ZVAD). Lower concentration of camptothecin (500 nM) induced comparable microparticle-release without loss of the culture confluence and without increase in annexin V-binding to the cells or DNA-fragmentation. Analyzed microparticles were free of nucleic acids and 95% of microparticles were 0.3-1 microm in size. Double-labeling flow cytometry assay showed that all annexin V-binding Microparticles expressed CD59 but only approximately 50% of these also expressed CD105. CONCLUSIONS Camptothecin treated HUVEC released different populations of annexin V-binding membrane microparticles at early stage after proapoptotic stimulation before detection of phosphatidylserine exposure on the cells or DNA fragmentation. The microparticle-release was ZVAD sensitive but was not enhanced at the executive phase of apoptosis. These observations offer a new insight into microparticle-release as a marker of endothelial stimulation and injury.
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Affiliation(s)
- Jan Šimák
- Laboratory of Cellular Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA
| | - Karel Holada
- Laboratory of Cellular Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA
| | - Jaroslav G Vostal
- Laboratory of Cellular Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA
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