201
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Yan H, Jiang J, Du A, Gao J, Zhang D, Song L. Genistein Enhances Radiosensitivity of Human Hepatocellular Carcinoma Cells by Inducing G2/M Arrest and Apoptosis. Radiat Res 2020; 193:286-300. [PMID: 32017668 DOI: 10.1667/rr15380.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
New radiosensitizers are urgently needed for radiation therapy patients with localized hepatocellular carcinoma (HCC) that is refractory to radical surgery. We previously found that genistein, a major soy isoflavone, exerts radioprotective effects on L-02 normal liver cells at low concentrations. Here, we report that 5 µM genistein shows less harm to L-02 cells than HCC cells and that it significantly enhances the radiosensitivity of HCC cells by enhancing DNA damage, chromosomal aberrations and cell cycle arrest at G2/M phase and by exacerbating apoptosis. Mechanistically, genistein aggravates X-ray-induced decreases in the levels of phospho-Bad (Ser136) but enhances the levels of phospho-Chk2 (Thr68), phospho-ATM (Ser1981) and γ-H2AX. Micro-array analysis indicated that downregulation of POU6F and CCNE2 expression and upregulation of FBXO32 and cyclin B1 expression might play vital roles in genistein-induced radiosensitivity. These findings suggest genistein as an interesting candidate for adjuvant radiotherapy for HCC and indicate that genistein causes less harm to normal cells than HCC cells by inducing G2/M arrest and apoptosis.
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Affiliation(s)
- Hongli Yan
- Department of Laboratory Medicine, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Jing Jiang
- Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China
| | - Aiying Du
- Department of Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, Shanghai, China
| | - Jinli Gao
- Department of Pathology, Shanghai East Hospital, Tongji University, Shanghai, China
| | - Daisong Zhang
- Department of Surgery, Penglai People's Hospital, Penglai 265600, Shandong Province, China
| | - Lihua Song
- Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China
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202
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Di Pillo E, Carrasco K, Brustolin B, Boufenzer A, Jolly L, Derive M, Lacolley P, Regnault V, Gibot S. Inhibition of triggering receptor expressed on myeloid cells-1 impairs thrombin generation. J Thromb Haemost 2020; 18:454-462. [PMID: 31680426 DOI: 10.1111/jth.14677] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 10/30/2019] [Indexed: 01/24/2023]
Abstract
BACKGROUND New evidence has shown the link between inflammation and thrombosis. Triggering receptor expressed on myeloid cells-1 (TREM-1) is an immunoreceptor expressed mostly on neutrophils and monocytes/macrophages. TREM-1 acts as an amplifier of the inflammatory response, and its pharmacological inhibition displays protective effects in various models of inflammatory disorders, in particular by dampening coagulation abnormalities and thrombocytopenia observed during acute inflammation. OBJECTIVES We aimed to decipher the role of TREM-1 in fostering thrombin generation. METHODS We measured thrombin generation (TG) by the use of calibrated automated thrombography with whole blood, and isolated primary human neutrophils and monocytes upon stimulation with lipopolysaccharide (LPS). Tissue factor (TF) expression was measured by flow cytometry and its activity by ELISA. Phosphatidylserine (PtdSer) exposure was determined by flow cytometry. A dodecapeptide (LR12) was used as a specific inhibitor of TREM-1. RESULTS LPS increased TG, TF expression, and activity, as well as the exposure of PtdSer on the surface of monocytes. LR12 dampened TF activity through the decrease of PtdSer exposure, leading to a reduction of thrombin generation. CONCLUSIONS TREM-1 inhibition decreases thrombin generation and could be an interesting target for the development of new inhibitors of leukocyte-associated thrombotic activity.
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Affiliation(s)
- Elisa Di Pillo
- Inserm UMR_S1116, Faculté de Médecine de Nancy, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | | | - Benjamin Brustolin
- Inserm UMR_S1116, Faculté de Médecine de Nancy, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | | | | | | | - Patrick Lacolley
- Inserm UMR_S1116, Faculté de Médecine de Nancy, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Véronique Regnault
- Inserm UMR_S1116, Faculté de Médecine de Nancy, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Sébastien Gibot
- Inserm UMR_S1116, Faculté de Médecine de Nancy, Université de Lorraine, Vandœuvre-lès-Nancy, France
- Service de Médecine Intensive Réanimation, Hôpital Central, Nancy, France
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203
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Nagata S, Sakuragi T, Segawa K. Flippase and scramblase for phosphatidylserine exposure. Curr Opin Immunol 2020; 62:31-38. [DOI: 10.1016/j.coi.2019.11.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/25/2019] [Indexed: 01/30/2023]
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204
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Infertility Caused by Inefficient Apoptotic Germ Cell Clearance in Xkr8-Deficient Male Mice. Mol Cell Biol 2020; 40:MCB.00402-19. [PMID: 31712393 DOI: 10.1128/mcb.00402-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/04/2019] [Indexed: 12/15/2022] Open
Abstract
During spermatogenesis, up to 75% of germ cells in the testes undergo apoptosis and are cleared by Sertoli cells. X-linked XK blood group-related 8 (Xkr8) is a plasma membrane protein that scrambles phospholipids in response to apoptotic signals, exposing phosphatidylserine (PtdSer). Here, we found that Xkr8 -/- male mice were infertile due to reduced sperm counts in their epididymides. Apoptotic stimuli could not induce PtdSer exposure in Xkr8 -/- germ cells. Consistent with the hypothesis that PtdSer functions as an "eat-me" signal to phagocytes, cells expressing phosphatidylserine receptor TIM4 and MER tyrosine kinase receptor efficiently engulfed apoptotic wild-type male germ cells but not Xkr8 -/- germ cells. Fluorescence and electron microscopy revealed Sertoli cells carrying engulfed and degenerated dead cells. However, many unengulfed apoptotic cells and residual bodies and much cell debris were present in Xkr8 -/- testes and epididymides. These results indicate that Xkr8-mediated PtdSer exposure is essential for the clearance of apoptotic germ cells by Sertoli cells. There was no apparent inflammation in Xkr8 -/- testes, suggesting that the unengulfed apoptotic cells may have undergone secondary necrosis, releasing noxious materials that affected the germ cells. Alternatively, failure to engulf the apoptotic germ cells may have caused the Sertoli cells to starve and lose their ability to support spermatogenesis.
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205
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Lin YC, Chipot C, Scheuring S. Annexin-V stabilizes membrane defects by inducing lipid phase transition. Nat Commun 2020; 11:230. [PMID: 31932647 PMCID: PMC6957514 DOI: 10.1038/s41467-019-14045-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 12/11/2019] [Indexed: 02/04/2023] Open
Abstract
Annexins are abundant cytoplasmic proteins, which bind to membranes that expose negatively charged phospholipids in a Ca2+-dependent manner. During cell injuries, the entry of extracellular Ca2+ activates the annexin membrane-binding ability, subsequently initiating membrane repair processes. However, the mechanistic action of annexins in membrane repair remains largely unknown. Here, we use high-speed atomic force microscopy (HS-AFM), fluorescence recovery after photobleaching (FRAP), confocal laser scanning microscopy (CLSM) and molecular dynamics simulations (MDSs) to analyze how annexin-V (A5) binds to phosphatidylserine (PS)-rich membranes leading to high Ca2+-concentrations at membrane, and then to changes in the dynamics and organization of lipids, eventually to a membrane phase transition. A5 self-assembly into lattices further stabilizes and likely structures the membrane into a gel phase. Our findings are compatible with the patch resealing through vesicle fusion mechanism in membrane repair and indicate that A5 retains negatively charged lipids in the inner leaflet in an injured cell. Annexins are cytoplasmic proteins, which bind to membranes exposing negatively charged phospholipids in a Ca2+-dependent manner. Here the authors use high-speed atomic force microscopy and other techniques to show that annexin-V self-assembles into highly structured lattices that lead to a membrane phase transition on PS-rich membranes.
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Affiliation(s)
- Yi-Chih Lin
- Department of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.,Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Christophe Chipot
- UMR 7019, Université de Lorraine, Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, Vandoeuvre-lès-Nancy, F-54500, France.,Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL, 61801, USA
| | - Simon Scheuring
- Department of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA. .,Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
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206
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Reconstitution of Proteoliposomes for Phospholipid Scrambling and Nonselective Channel Assays. Methods Mol Biol 2020; 2127:207-225. [PMID: 32112325 DOI: 10.1007/978-1-0716-0373-4_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Phospholipid scramblases catalyze the rapid trans-bilayer movement of lipids down their concentration gradients. This process is essential for numerous cellular signaling functions including cell fusion, blood coagulation, and apoptosis. The importance of scramblases is highlighted by the number of human diseases caused by mutations in these proteins. Because of their indispensable function, it is essential to understand and characterize the molecular function of phospholipid scramblases. Powerful tools to measure lipid transport in cells are available. However, these approaches provide limited mechanistic insights into the molecular bases of scrambling. Here we describe in detail an in vitro phospholipid scramblase assay and the accompanying analysis which allows for determination of the macroscopic rate constants associated with phospholipid scrambling. Notably, members of the TMEM16 family of scramblases also function as nonselective ion channels. To better understand the physiological relevance of this channel function as well as its relationship to the scrambling activity of the TMEM16s we also describe in detail an in vitro flux assay to measure nonselective channel activity. Together, these two assays can be used to investigate the dual activities of the TMEM16 scramblases/nonselective channels.
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207
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Quaglia M, Dellepiane S, Guglielmetti G, Merlotti G, Castellano G, Cantaluppi V. Extracellular Vesicles as Mediators of Cellular Crosstalk Between Immune System and Kidney Graft. Front Immunol 2020; 11:74. [PMID: 32180768 PMCID: PMC7057849 DOI: 10.3389/fimmu.2020.00074] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/13/2020] [Indexed: 12/11/2022] Open
Abstract
Extracellular vesicles (EVs) are known immune-modulators exerting a critical role in kidney transplantation (KT). EV bioactive cargo includes graft antigens, costimulatory/inhibitory molecules, cytokines, growth factors, and functional microRNAs (miRNAs) that may modulate expression of recipient cell genes. As paracrine factors, neutrophil- and macrophage-derived EVs exert immunosuppressive and immune-stimulating effects on dendritic cells, respectively. Dendritic cell-derived EVs mediate alloantigen spreading and modulate antigen presentation to T lymphocytes. At systemic level, EVs exert pleiotropic effects on complement and coagulation. Depending on their biogenesis, they can amplify complement activation or shed complement inhibitors and prevent cell lysis. Likewise, endothelial- and platelet-derived EVs can exert procoagulant/prothrombotic effects and also promote endothelial survival and angiogenesis after ischemic injury. Kidney endothelial- and tubular-derived EVs play a key role in ischemia-reperfusion injury (IRI) and during the healing process; additionally, they can trigger rejection by inducing both alloimmune and autoimmune responses. Endothelial EVs have procoagulant/pro-inflammatory effects and can release sequestered self-antigens, generating a tissue-specific autoimmunity. Renal tubule-derived EVs shuttle pro-fibrotic mediators (TGF-β and miR-21) to interstitial fibroblasts and modulate neutrophil and T-lymphocyte influx. These processes can lead to peritubular capillary rarefaction and interstitial fibrosis-tubular atrophy. Different EVs, including those from mesenchymal stromal cells (MSCs), have been employed as a therapeutic tool in experimental models of rejection and IRI. These particles protect tubular and endothelial cells (by inhibition of apoptosis and inflammation-fibrogenesis or by inducing autophagy) and stimulate tissue regeneration (by triggering angiogenesis, cell proliferation, and migration). Finally, urinary and serum EVs represent potential biomarkers for delayed graft function (DGF) and acute rejection. In conclusion, EVs sustain an intricate crosstalk between graft tissue and innate/adaptive immune systems. EVs play a major role in allorecognition, IRI, autoimmunity, and alloimmunity and are promising as biomarkers and therapeutic tools in KT.
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Affiliation(s)
- Marco Quaglia
- Nephrology and Kidney Transplantation Unit, Department of Translational Medicine, University of Piemonte Orientale (UPO), Novara, Italy
- Center for Autoimmune and Allergic Diseases (CAAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Sergio Dellepiane
- Nephrology and Kidney Transplantation Unit, Department of Translational Medicine, University of Piemonte Orientale (UPO), Novara, Italy
- Center for Autoimmune and Allergic Diseases (CAAD), University of Piemonte Orientale (UPO), Novara, Italy
- Division of Hematology/Medical Oncology, Icahn School of Medicine at Mount Sinai Hospital, The Tisch Cancer Institute, New York, NY, United States
| | - Gabriele Guglielmetti
- Nephrology and Kidney Transplantation Unit, Department of Translational Medicine, University of Piemonte Orientale (UPO), Novara, Italy
- Center for Autoimmune and Allergic Diseases (CAAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Guido Merlotti
- Nephrology and Kidney Transplantation Unit, Department of Translational Medicine, University of Piemonte Orientale (UPO), Novara, Italy
- Center for Autoimmune and Allergic Diseases (CAAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Giuseppe Castellano
- Nephrology Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Vincenzo Cantaluppi
- Nephrology and Kidney Transplantation Unit, Department of Translational Medicine, University of Piemonte Orientale (UPO), Novara, Italy
- Center for Autoimmune and Allergic Diseases (CAAD), University of Piemonte Orientale (UPO), Novara, Italy
- *Correspondence: Vincenzo Cantaluppi
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208
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Klein ME, Mauch S, Rieckmann M, Martínez DG, Hause G, Noutsias M, Hofmann U, Lucas H, Meister A, Ramos G, Loppnow H, Mäder K. Phosphatidylserine (PS) and phosphatidylglycerol (PG) nanodispersions as potential anti-inflammatory therapeutics: Comparison of in vitro activity and impact of pegylation. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2020; 23:102096. [DOI: 10.1016/j.nano.2019.102096] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 07/01/2019] [Accepted: 09/09/2019] [Indexed: 02/08/2023]
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209
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Svenningsen P, Sabaratnam R, Jensen BL. Urinary extracellular vesicles: Origin, role as intercellular messengers and biomarkers; efficient sorting and potential treatment options. Acta Physiol (Oxf) 2020; 228:e13346. [PMID: 31334916 DOI: 10.1111/apha.13346] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/16/2019] [Accepted: 07/16/2019] [Indexed: 12/14/2022]
Abstract
Urinary extracellular vesicles (uEVs) are a heterogenous group of vesicles consisting mainly of microvesicles and exosomes that originate predominantly (99.96%) from kidney, the urinary tract epithelium and the male reproductive tract. Secreted EVs contain molecular cargo from parental cells and provide an attractive source for biomarkers, a potential readout of physiological and pathophysiological mechanisms, and events associated with the urinary system. uEVs are readily enriched and isolated from urine samples and we review 6 standard methods that allow for downstream analysis of the uEV cargo. Although the use of uEVs as a surrogate readout for physiological changes in tissue protein levels is widespread, the protein abundance in uEVs is affected significantly by mechanisms that regulate protein sorting and secretion in uEVs. Data suggest that baseline kidney tissue and uEV levels of apical membrane-associated electrolyte transport proteins are not directly related in human patients. Recent evidence indicates that EVs may contribute to physiological and pathophysiological intercellular signalling and EVs confer protection against renal ischemia-reperfusion injury. The therapeutic use of EVs as information carriers has mainly been explored in vitro and a major hurdle lies in the translation of the in vitro findings into an in vivo setting. Thus, the EV research field is moving from a technical focus to a more physiological focus, allowing for a deeper understanding of human physiology, development of diagnostic tools and potential treatment strategies for precision medicine.
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Affiliation(s)
- Per Svenningsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | - Rugivan Sabaratnam
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine University of Southern Denmark Odense Denmark
- Section of Molecular Diabetes & Metabolism, Institute of Clinical Research, Steno Diabetes Center Odense Odense University Hospital Odense C Denmark
| | - Boye L. Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine University of Southern Denmark Odense Denmark
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210
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Ryoden Y, Fujii T, Segawa K, Nagata S. Functional Expression of the P2X7 ATP Receptor Requires Eros. THE JOURNAL OF IMMUNOLOGY 2019; 204:559-568. [PMID: 31862710 DOI: 10.4049/jimmunol.1900448] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 11/20/2019] [Indexed: 02/04/2023]
Abstract
In response to extracellular ATP, the purinergic receptor P2X7 mediates various biological processes, including phosphatidylserine (PtdSer) exposure, phospholipid scrambling, dye uptake, ion transport, and IL-1β production. A genome-wide CRISPR screen for molecules responsible for ATP-induced PtdSer exposure identified a transmembrane protein, essential for reactive oxygen species (Eros), as a necessary component for P2X7 expression. An Eros-null mouse T cell line lost the ability to expose PtdSer, to scramble phospholipids, and to internalize a dye YO-PRO-1 and Ca2+ ions. Eros-null mutation abolished the ability of an LPS-primed human THP-1 macrophage cell line and mouse bone marrow-derived macrophages to secrete IL-1β in response to ATP. Eros is localized to the endoplasmic reticulum and functions as a chaperone for NADPH oxidase components. Similarly, Eros at the endoplasmic reticulum transiently associated with P2X7 to promote the formation of a stable homotrimeric complex of P2X7. These results indicated that Eros acts as a chaperone not only for NADPH oxidase, but also for P2X7, and contributes to the innate immune reaction.
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Affiliation(s)
- Yuta Ryoden
- Laboratory of Biochemistry and Immunology, World Premier International Research Center, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Toshihiro Fujii
- Laboratory of Biochemistry and Immunology, World Premier International Research Center, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Katsumori Segawa
- Laboratory of Biochemistry and Immunology, World Premier International Research Center, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Shigekazu Nagata
- Laboratory of Biochemistry and Immunology, World Premier International Research Center, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
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211
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Conserved mechanism of phospholipid substrate recognition by the P4-ATPase Neo1 from Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158581. [PMID: 31786280 DOI: 10.1016/j.bbalip.2019.158581] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 12/17/2022]
Abstract
The type IV P-type ATPases (P4-ATPases) thus far characterized are lipid flippases that transport specific substrates, such as phosphatidylserine (PS) and phosphatidylethanolamine (PE), from the exofacial leaflet to the cytofacial leaflet of membranes. This transport activity generates compositional asymmetry between the two leaflets important for signal transduction, cytokinesis, vesicular transport, and host-pathogen interactions. Most P4-ATPases function as a heterodimer with a β-subunit from the Cdc50 protein family, but Neo1 from Saccharomyces cerevisiae and its metazoan orthologs lack a β-subunit requirement and it is unclear how these proteins transport substrate. Here we tested if residues linked to lipid substrate recognition in other P4-ATPases also contribute to Neo1 function in budding yeast. Point mutations altering entry gate residues in the first (Q209A) and fourth (S457Q) transmembrane segments of Neo1, where phospholipid substrate would initially be selected, disrupt PS and PE membrane asymmetry, but do not perturb growth of cells. Mutation of both entry gate residues inactivates Neo1, and cells expressing this variant are inviable. We also identified a gain-of-function mutation in the second transmembrane segment of Neo1 (Neo1[Y222S]), predicted to help form the entry gate, that substantially enhances Neo1's ability to replace the function of a well characterized phospholipid flippase, Drs2, in establishing PS and PE asymmetry. These results suggest a common mechanism for substrate recognition in widely divergent P4-ATPases.
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212
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Tran JQ, Muench MO, Heitman JW, Jackman RP. Pathogen reduction with riboflavin and ultraviolet light induces a quasi-apoptotic state in blood leukocytes. Transfusion 2019; 59:3501-3510. [PMID: 31599981 DOI: 10.1111/trf.15516] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/26/2019] [Accepted: 08/19/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND Alloimmunization to platelet-rich plasma (PRP) transfusions can cause adverse reactions such as platelet refractoriness or transplant rejection. Pathogen reduction treatment with ultraviolet light and riboflavin (UV + R) of allogeneic PRP was shown to reduce allogeneic antibody responses and confer partial antigen-specific immune tolerance to subsequent transfusions in mice. Studies have shown that UV + R was effective at both rapidly killing donor white blood cells (WBCs) and reducing their ability to stimulate an allogeneic response in vitro. However, the manner in which UV + R induces WBC death and its associated role in the immune response to treated PRP is unknown. METHODS AND MATERIALS This study evaluates whether UV + R causes WBC apoptosis by examining phosphatidylserine exposure on the plasma membrane, membrane asymmetry, caspase activity, and chromatin condensation by flow cytometry. The immunogenicity of WBCs killed with UV + R versus apoptotic or necrotic pathways was also examined in vivo. RESULTS WBCs after UV + R exhibited early apoptotic-like characteristics including phosphatidylserine exposure on the outer leaflet of the plasma membrane and loss of membrane asymmetry, but unlike canonical apoptotic cells, caspase activity and chromatin condensation were not apparent. However, in vivo studies demonstrated, unlike untreated or necrotic WBCs, both apoptotic WBCs and UV + R-treated WBCs failed to prime alloantibody responses to subsequent untreated transfusions. CONCLUSION Overall, the mechanism of WBC death following UV + R treatment shares some membrane characteristics of early apoptosis but is distinct from classic apoptosis. Despite these differences, UV + R-treated and apoptotic WBCs both offer some protection from alloimmunization.
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Affiliation(s)
| | - Marcus O Muench
- Vitalant Research Institute, San Francisco, California.,Department of Laboratory Medicine, University of California, San Francisco, California
| | | | - Rachael P Jackman
- Vitalant Research Institute, San Francisco, California.,Department of Laboratory Medicine, University of California, San Francisco, California
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213
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Abstract
The plasma membrane is a ∼4 nm thick phospholipid bilayer that defines the boundary of a cell, segregating internal content from the external environment. Its hydrophobic interior presents a barrier to the exchange of ions and polar solutes between the inside and outside of the cell, as well as to the spontaneous reorientation of lipids between the two leaflets of the bilayer. Specific transport systems, e.g. ion channels and lipid flippases, are needed to enable the passage of these molecules across the plasma membrane at physiologically relevant rates. Although the influential fluid mosaic membrane model of 1972 depicted the membrane as an archipelago of protein islands within a uniform sea of lipids, its micrometer-scale lateral heterogeneity was recognized relatively quickly, evolving into the current picture of structural granularity at the nanoscale.
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Affiliation(s)
- Toshihide Kobayashi
- UMR 7213 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, F - 67401 Illkirch, France
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065, USA.
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214
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Platelet CD36 signaling through ERK5 promotes caspase-dependent procoagulant activity and fibrin deposition in vivo. Blood Adv 2019; 2:2848-2861. [PMID: 30381401 DOI: 10.1182/bloodadvances.2018025411] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 09/28/2018] [Indexed: 12/12/2022] Open
Abstract
Dyslipidemia is a risk factor for clinically significant thrombotic events. In this condition, scavenger receptor CD36 potentiates platelet reactivity through recognition of circulating oxidized lipids. CD36 promotes thrombosis by activating redox-sensitive signaling molecules, such as the MAPK extracellular signal-regulated kinase 5 (ERK5). However, the events downstream of platelet ERK5 are not clear. In this study, we report that oxidized low-density lipoprotein (oxLDL) promotes exposure of procoagulant phosphatidylserine (PSer) on platelet surfaces. Studies using pharmacologic inhibitors indicate that oxLDL-CD36 interaction-induced PSer exposure requires apoptotic caspases in addition to the downstream CD36-signaling molecules Src kinases, hydrogen peroxide, and ERK5. Caspases promote PSer exposure and, subsequently, recruitment of the prothrombinase complex, resulting in the generation of fibrin from the activation of thrombin. Caspase activity was observed when platelets were stimulated with oxLDL. This was prevented by inhibiting CD36 and ERK5. Furthermore, oxLDL potentiates convulxin/glycoprotein VI-mediated fibrin formation by platelets, which was prevented when CD36, ERK5, and caspases were inhibited. Using 2 in vivo arterial thrombosis models in apoE-null hyperlipidemic mice demonstrated enhanced arterial fibrin accumulation upon vessel injury. Importantly, absence of ERK5 in platelets or mice lacking CD36 displayed decreased fibrin accumulation in high-fat diet-fed conditions comparable to that seen in chow diet-fed animals. These findings suggest that platelet signaling through CD36 and ERK5 induces a procoagulant phenotype in the hyperlipidemic environment by enhancing caspase-mediated PSer exposure.
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215
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Kawano M, Nagata S. Efferocytosis and autoimmune disease. Int Immunol 2019; 30:551-558. [PMID: 30165442 PMCID: PMC6234909 DOI: 10.1093/intimm/dxy055] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 08/21/2018] [Indexed: 12/14/2022] Open
Abstract
An enormous number of cells in the body die by apoptosis during development and under homeostasis. Apoptotic cells are swiftly engulfed by macrophages and digested into units. This removal of apoptotic cells is called ‘efferocytosis’. For efferocytosis, macrophages recognize phosphatidylserine (PtdSer) exposed on the cell surface as an ‘eat me’ signal. In healthy cells, PtdSer is exclusively localized to the inner leaflet of the plasma membrane by the action of flippases. When cells undergo apoptosis, caspase cleaves flippases to inactivate them, while it cleaves pro-scramblases to active scramblases, which quickly translocate PtdSer to the cell surface. The PtdSer is then recognized by PtdSer-binding proteins or by PtdSer receptors on macrophages, which subsequently engulf the apoptotic cells. When efferocytosis fails, apoptotic cells can rupture, releasing cellular materials that can evoke an autoimmune response. Thus, a defect in the PtdSer-exposing or PtdSer-recognizing processes triggers autoimmunity, leading to a systemic lupus erythematosus-type autoimmune disease.
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Affiliation(s)
- Mahiru Kawano
- Laboratory of Biochemistry & Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Shigekazu Nagata
- Laboratory of Biochemistry & Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
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216
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Abstract
Tissue macrophages rapidly recognize and engulf apoptotic cells. These events require the display of so-called eat-me signals on the apoptotic cell surface, the most fundamental of which is phosphatidylserine (PtdSer). Externalization of this phospholipid is catalysed by scramblase enzymes, several of which are activated by caspase cleavage. PtdSer is detected both by macrophage receptors that bind to this phospholipid directly and by receptors that bind to a soluble bridging protein that is independently bound to PtdSer. Prominent among the latter receptors are the MER and AXL receptor tyrosine kinases. Eat-me signals also trigger macrophages to engulf virus-infected or metabolically traumatized, but still living, cells, and this 'murder by phagocytosis' may be a common phenomenon. Finally, the localized presentation of PtdSer and other eat-me signals on delimited cell surface domains may enable the phagocytic pruning of these 'locally dead' domains by macrophages, most notably by microglia of the central nervous system.
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Affiliation(s)
- Greg Lemke
- Molecular Neurobiology Laboratory, Immunobiology and Microbial Pathogenesis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.
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217
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Yang M, Silverstein RL. CD36 and ERK5 link dyslipidemia to apoptotic-like platelet procoagulant function. Curr Opin Hematol 2019; 26:357-365. [PMID: 31261174 PMCID: PMC9308374 DOI: 10.1097/moh.0000000000000522] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE OF REVIEW Metabolic diseases, including dyslipidemia, diabetes mellitus, and chronic inflammation are risk factors for clinically significant thrombotic events. Thrombosis in these settings is multifaceted with coordinated mechanisms between platelet activation and the hemostatic pathways. This review focuses on recent advances in platelet procoagulant and apoptotic signaling with emphasis on the pathophysiologic mechanisms induced by platelet CD36 in dyslipidemia, and the key unaddressed questions relating to the field. RECENT FINDINGS CD36 promotes platelet activation and increases the risk for thrombosis through signaling events. These include generation of reactive oxygen species, activation of redox-sensitive MAP kinase ERK5, and promotion of a pro-thrombotic phenotype. CD36 promotes phosphatidylserine externalization leading to a procoagulant function downstream from MAP kinase ERK5 that is separate from a pro-aggregatory function. Phosphatidylserine externalization requires maladaptive caspase activation, promotes assembly of the factor tenase and prothrombinase complex, and promotes fibrin formation. It is distinct from the canonical pathways mediating platelet procoagulant function by strong physiologic stimuli or by the platelet apoptotic-like Bak/Bax-mediated pathway for cellular clearance. SUMMARY Understanding CD36 signaling in the context of dyslipidemia, or other metabolic diseases will identify important and novel signaling hubs that could be potential therapeutic targets for intervention without impacting hemostasis.
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Affiliation(s)
- Moua Yang
- Department of Biochemistry, Medical College of Wisconsin
- Blood Research Institute, Versiti Blood Center of Wisconsin
| | - Roy L. Silverstein
- Blood Research Institute, Versiti Blood Center of Wisconsin
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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218
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Xia T, Zhang B, Duan W, Li Y, Zhang J, Song J, Zheng Y, Wang M. Hepatoprotective efficacy of Shanxi aged vinegar extract against oxidative damage in vitro and in vivo. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.103448] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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219
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Veit M, Ahrens B, Seidel J, Sommer A, Bhakdi S, Reiss K. Mutagenesis of the ADAM17-phosphatidylserine-binding motif leads to embryonic lethality in mice. Life Sci Alliance 2019; 2:2/5/e201900430. [PMID: 31455669 PMCID: PMC6712283 DOI: 10.26508/lsa.201900430] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/19/2019] [Accepted: 08/19/2019] [Indexed: 12/26/2022] Open
Abstract
ADAM17, prominent member of the "Disintegrin and Metalloproteinase" (ADAM) family, controls vital cellular functions through cleavage of transmembrane substrates. Several of these play central roles in oncogenesis and inflammation, yet despite its importance, the mechanism by which ADAM17 is activated is not fully understood. We recently presented evidence that surface exposure of phosphatidylserine (PS) is the penultimate event required for sheddase activation, which occurs upon binding of a membrane-proximal, cationic binding motif to the anionic phospholipid headgroup. Here, we show that mutagenesis of the 3 amino acids constituting the PS-binding motif leads to embryonic lethality in mice. Heterozygotes showed no abnormalities. Primary hepatocytes and fibroblasts were analysed and found to express the mutant protease on the cell surface. However, PMA-stimulated release of ADAM17 substrates was completely abolished. The results directly support the novel concept of transiently externalised PS as essential trigger of extracellular protease function in vivo.
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Affiliation(s)
- Martin Veit
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Björn Ahrens
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Jana Seidel
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Anselm Sommer
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Sucharit Bhakdi
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Karina Reiss
- Department of Dermatology, University of Kiel, Kiel, Germany
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220
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Phosphatidylserine flipping by the P4-ATPase ATP8A2 is electrogenic. Proc Natl Acad Sci U S A 2019; 116:16332-16337. [PMID: 31371510 DOI: 10.1073/pnas.1910211116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phospholipid flippases (P4-ATPases) utilize ATP to translocate specific phospholipids from the exoplasmic leaflet to the cytoplasmic leaflet of biological membranes, thus generating and maintaining transmembrane lipid asymmetry essential for a variety of cellular processes. P4-ATPases belong to the P-type ATPase protein family, which also encompasses the ion transporting P2-ATPases: Ca2+-ATPase, Na+,K+-ATPase, and H+,K+-ATPase. In comparison with the P2-ATPases, understanding of P4-ATPases is still very limited. The electrogenicity of P4-ATPases has not been explored, and it is not known whether lipid transfer between membrane bilayer leaflets can lead to displacement of charge across the membrane. A related question is whether P4-ATPases countertransport ions or other substrates in the opposite direction, similar to the P2-ATPases. Using an electrophysiological method based on solid supported membranes, we observed the generation of a transient electrical current by the mammalian P4-ATPase ATP8A2 in the presence of ATP and the negatively charged lipid substrate phosphatidylserine, whereas only a diminutive current was generated with the lipid substrate phosphatidylethanolamine, which carries no or little charge under the conditions of the measurement. The current transient seen with phosphatidylserine was abolished by the mutation E198Q, which blocks dephosphorylation. Likewise, mutation I364M, which causes the neurological disorder cerebellar ataxia, mental retardation, and disequilibrium (CAMRQ) syndrome, strongly interfered with the electrogenic lipid translocation. It is concluded that the electrogenicity is associated with a step in the ATPase reaction cycle directly involved in translocation of the lipid. These measurements also showed that no charged substrate is being countertransported, thereby distinguishing the P4-ATPase from P2-ATPases.
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221
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Ye W, Han TW, He M, Jan YN, Jan LY. Dynamic change of electrostatic field in TMEM16F permeation pathway shifts its ion selectivity. eLife 2019; 8:e45187. [PMID: 31318330 PMCID: PMC6690719 DOI: 10.7554/elife.45187] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 07/17/2019] [Indexed: 12/11/2022] Open
Abstract
TMEM16F is activated by elevated intracellular Ca2+, and functions as a small-conductance ion channel and as a phospholipid scramblase. In contrast to its paralogs, the TMEM16A/B calcium-activated chloride channels, mouse TMEM16F has been reported as a cation-, anion-, or non-selective ion channel, without a definite conclusion. Starting with the Q559K mutant that shows no current rundown and less outward rectification in excised patch, we found that the channel shifted its ion selectivity in response to the change of intracellular Ca2+ concentration, with an increased permeability ratio of Cl- to Na+ (PCl-/PNa+) at a higher Ca2+ level. The gradual shift of relative ion permeability did not correlate with the channel activation state. Instead, it was indicative of an alteration of electrostatic field in the permeation pathway. The dynamic change of ion selectivity suggests a charge-screening mechanism for TMEM16F ion conduction, and it provides hints to further studies of TMEM16F physiological functions.
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Affiliation(s)
- Wenlei Ye
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Tina W Han
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Mu He
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Yuh Nung Jan
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
- Department of Biochemistry and BiophysicsUniversity of California, San FranciscoSan FranciscoUnited States
| | - Lily Yeh Jan
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
- Department of Biochemistry and BiophysicsUniversity of California, San FranciscoSan FranciscoUnited States
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222
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
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223
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Muller MP, Jiang T, Sun C, Lihan M, Pant S, Mahinthichaichan P, Trifan A, Tajkhorshid E. Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation. Chem Rev 2019; 119:6086-6161. [PMID: 30978005 PMCID: PMC6506392 DOI: 10.1021/acs.chemrev.8b00608] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.
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Affiliation(s)
- Melanie P. Muller
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chang Sun
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paween Mahinthichaichan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Anda Trifan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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224
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Manna M, Nieminen T, Vattulainen I. Understanding the Role of Lipids in Signaling Through Atomistic and Multiscale Simulations of Cell Membranes. Annu Rev Biophys 2019; 48:421-439. [DOI: 10.1146/annurev-biophys-052118-115553] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cell signaling controls essentially all cellular processes. While it is often assumed that proteins are the key architects coordinating cell signaling, recent studies have shown more and more clearly that lipids are also involved in signaling processes in a number of ways. Lipids do, for instance, act as messengers, modulate membrane receptor conformation and dynamics, and control membrane receptor partitioning. Further, through structural modifications such as oxidation, the functions of lipids as part of signaling processes can be modified. In this context, in this article we discuss the understanding recently revealed by atomistic and coarse-grained computer simulations of nanoscale processes and underlying physicochemical principles related to lipids’ functions in cellular signaling.
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Affiliation(s)
- Moutusi Manna
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh 462 066, India
| | - Tuomo Nieminen
- Computational Physics Laboratory, Tampere University, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Computational Physics Laboratory, Tampere University, FI-33014 Tampere, Finland
- Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland
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225
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Takar M, Huang Y, Graham TR. The PQ-loop protein Any1 segregates Drs2 and Neo1 functions required for viability and plasma membrane phospholipid asymmetry. J Lipid Res 2019; 60:1032-1042. [PMID: 30824614 PMCID: PMC6495175 DOI: 10.1194/jlr.m093526] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Indexed: 02/06/2023] Open
Abstract
Membrane asymmetry is a key organizational feature of the plasma membrane. Type IV P-type ATPases (P4-ATPases) are phospholipid flippases that establish membrane asymmetry by translocating phospholipids, such as phosphatidylserine (PS) and phospatidylethanolamine, from the exofacial leaflet to the cytosolic leaflet. Saccharomyces cerevisiae expresses five P4-ATPases: Drs2, Neo1, Dnf1, Dnf2, and Dnf3. The inactivation of Neo1 is lethal, suggesting Neo1 mediates an essential function not exerted by the other P4-ATPases. However, the disruption of ANY1, which encodes a PQ-loop membrane protein, allows the growth of neo1Δ and reveals functional redundancy between Golgi-localized Neo1 and Drs2. Here we show Drs2 PS flippase activity is required to support neo1Δ any1Δ viability. Additionally, a Dnf1 variant with enhanced PS flipping ability can replace Drs2 and Neo1 function in any1Δ cells. any1Δ also suppresses drs2Δ growth defects but not the loss of membrane asymmetry. Any1 overexpression perturbs the growth of cells but does not disrupt membrane asymmetry. Any1 coimmunoprecipitates with Neo1, an association prevented by the Any1-inactivating mutation D84G. These results indicate a critical role for PS flippase activity in Golgi membranes to sustain viability and suggests Any1 regulates Golgi membrane remodeling through protein-protein interactions rather than a previously proposed scramblase activity.
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Affiliation(s)
- Mehmet Takar
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Yannan Huang
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235.
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226
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Membrane Lipid Composition: Effect on Membrane and Organelle Structure, Function and Compartmentalization and Therapeutic Avenues. Int J Mol Sci 2019; 20:ijms20092167. [PMID: 31052427 PMCID: PMC6540057 DOI: 10.3390/ijms20092167] [Citation(s) in RCA: 401] [Impact Index Per Article: 80.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/26/2019] [Accepted: 04/30/2019] [Indexed: 12/17/2022] Open
Abstract
Biological membranes are key elements for the maintenance of cell architecture and physiology. Beyond a pure barrier separating the inner space of the cell from the outer, the plasma membrane is a scaffold and player in cell-to-cell communication and the initiation of intracellular signals among other functions. Critical to this function is the plasma membrane compartmentalization in lipid microdomains that control the localization and productive interactions of proteins involved in cell signal propagation. In addition, cells are divided into compartments limited by other membranes whose integrity and homeostasis are finely controlled, and which determine the identity and function of the different organelles. Here, we review current knowledge on membrane lipid composition in the plasma membrane and endomembrane compartments, emphasizing its role in sustaining organelle structure and function. The correct composition and structure of cell membranes define key pathophysiological aspects of cells. Therefore, we explore the therapeutic potential of manipulating membrane lipid composition with approaches like membrane lipid therapy, aiming to normalize cell functions through the modification of membrane lipid bilayers.
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227
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Le T, Jia Z, Le SC, Zhang Y, Chen J, Yang H. An inner activation gate controls TMEM16F phospholipid scrambling. Nat Commun 2019; 10:1846. [PMID: 31015464 PMCID: PMC6478717 DOI: 10.1038/s41467-019-09778-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/27/2019] [Indexed: 12/15/2022] Open
Abstract
Transmembrane protein 16F (TMEM16F) is an enigmatic Ca2+-activated phospholipid scramblase (CaPLSase) that passively transports phospholipids down their chemical gradients and mediates blood coagulation, bone development and viral infection. Despite recent advances in the structure and function understanding of TMEM16 proteins, how mammalian TMEM16 CaPLSases open and close, or gate their phospholipid permeation pathways remains unclear. Here we identify an inner activation gate, which is established by three hydrophobic residues, F518, Y563 and I612, in the middle of the phospholipid permeation pathway of TMEM16F-CaPLSase. Disrupting the inner gate profoundly alters TMEM16F phospholipid permeation. Lysine substitutions of F518 and Y563 even lead to constitutively active CaPLSases that bypass Ca2+-dependent activation. Strikingly, an analogous lysine mutation to TMEM16F-F518 in TMEM16A (L543K) is sufficient to confer CaPLSase activity to the Ca2+-activated Cl- channel (CaCC). The identification of an inner activation gate can help elucidate the gating and permeation mechanism of TMEM16 CaPLSases and channels.
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Affiliation(s)
- Trieu Le
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Zhiguang Jia
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
| | - Son C Le
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Yang Zhang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, 01003, MA, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA.
- Department of Neurobiology, Duke University Medical Center, Durham, 27710, NC, USA.
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228
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Zdenek CN, Hay C, Arbuckle K, Jackson TNW, Bos MHA, Op den Brouw B, Debono J, Allen L, Dunstan N, Morley T, Herrera M, Gutiérrez JM, Williams DJ, Fry BG. Coagulotoxic effects by brown snake (Pseudonaja) and taipan (Oxyuranus) venoms, and the efficacy of a new antivenom. Toxicol In Vitro 2019; 58:97-109. [PMID: 30910521 DOI: 10.1016/j.tiv.2019.03.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 03/12/2019] [Accepted: 03/21/2019] [Indexed: 01/03/2023]
Abstract
Snakebite is a neglected tropical disease that disproportionately affects the poor. Antivenom is the only specific and effective treatment for snakebite, but its distribution is severely limited by several factors, including the prohibitive cost of some products. Papua New Guinea (PNG) is a snakebite hotspot but the high costs of Australian antivenoms (thousands of dollars per treatment) makes it unaffordable in PNG. A more economical taipan antivenom has recently been developed at the Instituto Clodomiro Picado (ICP) in Costa Rica for PNG and is currently undergoing clinical trials for the treatment of envenomations by coastal taipans (Oxyuranus scutellatus). In addition to potentially having the capacity to neutralise the effects of envenomations of non-PNG taipans, this antivenom may have the capacity to neutralise coagulotoxins in venom from closely related brown snakes (Pseudonaja spp.) also found in PNG. Consequently, we investigated the cross-reactivity of taipan antivenom across the venoms of all Oxyuranus and Pseudonaja species. In addition, to ascertain differences in venom biochemistry that influence variation in antivenom efficacy, we tested for relative cofactor dependence. We found that the new ICP taipan antivenom exhibited high selectivity for Oxyuranus venoms and only low to moderate cross-reactivity with any Pseudonaja venoms. Consistent with this genus level distinction in antivenom efficacy were fundamental differences in the venom biochemistry. Not only were the Pseudonaja venoms significantly more procoagulant, but they were also much less dependent upon the cofactors calcium and phospholipid. There was a strong correlation between antivenom efficacy, clotting time and cofactor dependence. This study sheds light on the structure-function relationships of the procoagulant toxins within these venoms and may have important clinical implications including for the design of next-generation antivenoms.
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Affiliation(s)
- Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Chris Hay
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia; Reptile Kingdom Australia, Carrara, QLD, Australia
| | - Kevin Arbuckle
- Department of Biosciences, College of Science, Swansea University, SA2 8PP, United Kingdom
| | - Timothy N W Jackson
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, 3010, VIC, Australia
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Albinusdreef 2, 2333, ZA, Leiden, the Netherlands
| | - Bianca Op den Brouw
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jordan Debono
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Luke Allen
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | - Nathan Dunstan
- Venom Supplies Pty Ltd, Stonewell Rd, Tanunda, SA 5352, Australia
| | | | - María Herrera
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - José M Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - David J Williams
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, University of Melbourne, 3010, VIC, Australia; Charles Campbell Toxinology Centre, School of Medicine and Health Sciences, University of Papua New Guinea, Boroko 121, National Capital District, Papua New Guinea
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia.
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229
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Liou AY, Molday LL, Wang J, Andersen JP, Molday RS. Identification and functional analyses of disease-associated P4-ATPase phospholipid flippase variants in red blood cells. J Biol Chem 2019; 294:6809-6821. [PMID: 30850395 DOI: 10.1074/jbc.ra118.007270] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/06/2019] [Indexed: 02/04/2023] Open
Abstract
ATP-dependent phospholipid flippase activity crucial for generating lipid asymmetry was first detected in red blood cell (RBC) membranes, but the P4-ATPases responsible have not been directly determined. Using affinity-based MS, we show that ATP11C is the only abundant P4-ATPase phospholipid flippase in human RBCs, whereas ATP11C and ATP8A1 are the major P4-ATPases in mouse RBCs. We also found that ATP11A and ATP11B are present at low levels. Mutations in the gene encoding ATP11C are responsible for blood and liver disorders, but the disease mechanisms are not known. Using heterologous expression, we show that the T415N substitution in the phosphorylation motif of ATP11C, responsible for congenital hemolytic anemia, reduces ATP11C expression, increases retention in the endoplasmic reticulum, and decreases ATPase activity by 61% relative to WT ATP11C. The I355K substitution in the transmembrane domain associated with cholestasis and anemia in mice was expressed at WT levels and trafficked to the plasma membrane but was devoid of activity. We conclude that the T415N variant causes significant protein misfolding, resulting in low protein expression, cellular mislocalization, and reduced functional activity. In contrast, the I355K variant folds and traffics normally but lacks key contacts required for activity. We propose that the loss in ATP11C phospholipid flippase activity coupled with phospholipid scramblase activity results in the exposure of phosphatidylserine on the surface of RBCs, decreasing RBC survival and resulting in anemia.
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Affiliation(s)
- Angela Y Liou
- From the Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada and
| | - Laurie L Molday
- From the Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada and
| | - Jiao Wang
- From the Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada and
| | - Jens Peter Andersen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Building 1160, DK-8000 Aarhus C, Denmark
| | - Robert S Molday
- From the Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada and
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230
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Kalienkova V, Clerico Mosina V, Bryner L, Oostergetel GT, Dutzler R, Paulino C. Stepwise activation mechanism of the scramblase nhTMEM16 revealed by cryo-EM. eLife 2019; 8:e44364. [PMID: 30785398 PMCID: PMC6414200 DOI: 10.7554/elife.44364] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 02/08/2019] [Indexed: 12/26/2022] Open
Abstract
Scramblases catalyze the movement of lipids between both leaflets of a bilayer. Whereas the X-ray structure of the protein nhTMEM16 has previously revealed the architecture of a Ca2+-dependent lipid scramblase, its regulation mechanism has remained elusive. Here, we have used cryo-electron microscopy and functional assays to address this question. Ca2+-bound and Ca2+-free conformations of nhTMEM16 in detergent and lipid nanodiscs illustrate the interactions with its environment and they reveal the conformational changes underlying its activation. In this process, Ca2+ binding induces a stepwise transition of the catalytic subunit cavity, converting a closed cavity that is shielded from the membrane in the absence of ligand, into a polar furrow that becomes accessible to lipid headgroups in the Ca2+-bound state. Additionally, our structures demonstrate how nhTMEM16 distorts the membrane at both entrances of the subunit cavity, thereby decreasing the energy barrier for lipid movement.
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Affiliation(s)
| | - Vanessa Clerico Mosina
- Department of Structural Biology, Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenThe Netherlands
| | - Laura Bryner
- Department of BiochemistryUniversity of ZurichZurichSwitzerland
| | - Gert T Oostergetel
- Department of Structural Biology, Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenThe Netherlands
| | - Raimund Dutzler
- Department of BiochemistryUniversity of ZurichZurichSwitzerland
| | - Cristina Paulino
- Department of Structural Biology, Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenThe Netherlands
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231
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Alvadia C, Lim NK, Clerico Mosina V, Oostergetel GT, Dutzler R, Paulino C. Cryo-EM structures and functional characterization of the murine lipid scramblase TMEM16F. eLife 2019; 8:e44365. [PMID: 30785399 PMCID: PMC6414204 DOI: 10.7554/elife.44365] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 02/19/2019] [Indexed: 12/13/2022] Open
Abstract
The lipid scramblase TMEM16F initiates blood coagulation by catalyzing the exposure of phosphatidylserine in platelets. The protein is part of a family of membrane proteins, which encompasses calcium-activated channels for ions and lipids. Here, we reveal features of murine TMEM16F (mTMEM16F) that underlie its function as a lipid scramblase and an ion channel. The cryo-EM data of mTMEM16F in absence and presence of Ca2+ define the ligand-free closed conformation of the protein and the structure of a Ca2+-bound intermediate. Both conformations resemble their counterparts of the scrambling-incompetent anion channel mTMEM16A, yet with distinct differences in the region of ion and lipid permeation. In conjunction with functional data, we demonstrate the relationship between ion conduction and lipid scrambling. Although activated by a common mechanism, both functions appear to be mediated by alternate protein conformations that are at equilibrium in the ligand-bound state.
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Affiliation(s)
| | - Novandy K Lim
- Department of BiochemistryUniversity of ZurichZurichSwitzerland
| | - Vanessa Clerico Mosina
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenNetherlands
| | - Gert T Oostergetel
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenNetherlands
| | - Raimund Dutzler
- Department of BiochemistryUniversity of ZurichZurichSwitzerland
| | - Cristina Paulino
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenNetherlands
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232
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Phosphorylation-mediated activation of mouse Xkr8 scramblase for phosphatidylserine exposure. Proc Natl Acad Sci U S A 2019; 116:2907-2912. [PMID: 30718401 DOI: 10.1073/pnas.1820499116] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The exposure of phosphatidylserine (PtdSer) to the cell surface is regulated by the down-regulation of flippases and the activation of scramblases. Xkr8 has been identified as a scramblase that is activated during apoptosis, but its exogenous expression in the mouse Ba/F3 pro B cell line induces constitutive PtdSer exposure. Here we found that this Xkr8-mediated PtdSer exposure occurred at 4 °C, but not at 20 °C, although its scramblase activity was observed at 20 °C. The Xkr8-mediated PtdSer exposure was inhibited by a kinase inhibitor and enhanced by phosphatase inhibitors. Phosphorylated Xkr8 was detected by Phos-tag PAGE, and a mass spectrometric and mutational analysis identified three phosphorylation sites. Their phosphomimic mutation rendered Xkr8 resistant to the kinase inhibitor for PtdSer exposure at 4 °C, but unlike phosphatase inhibitors, it did not induce constitutive PtdSer exposure at 20 °C. On the other hand, when the flippase genes were deleted, the Xkr8 induced constitutive PtdSer exposure at high temperature, indicating that the flippase activity normally counteracted Xkr8's ability to expose PtdSer. These results indicate that PtdSer exposure can be increased by the phosphorylation-mediated activation of Xkr8 scramblase and flippase down-regulation.
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233
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Le T, Le SC, Yang H. Drosophila Subdued is a moonlighting transmembrane protein 16 (TMEM16) that transports ions and phospholipids. J Biol Chem 2019; 294:4529-4537. [PMID: 30700552 DOI: 10.1074/jbc.ac118.006530] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/25/2019] [Indexed: 12/19/2022] Open
Abstract
Transmembrane protein 16 (TMEM16) family members play numerous important physiological roles, ranging from controlling membrane excitability and secretion to mediating blood coagulation and viral infection. These diverse functions are largely due to their distinct biophysical properties. Mammalian TMEM16A and TMEM16B are Ca2+-activated Cl- channels (CaCCs), whereas mammalian TMEM16F, fungal afTMEM16, and nhTMEM16 are moonlighting (multifunctional) proteins with both Ca2+-activated phospholipid scramblase (CaPLSase) and Ca2+-activated, nonselective ion channel (CAN) activities. To further understand the biological functions of the enigmatic TMEM16 proteins in different organisms, here, by combining an improved annexin V-based CaPLSase-imaging assay with inside-out patch clamp technique, we thoroughly characterized Subdued, a Drosophila TMEM16 ortholog. We show that Subdued is also a moonlighting transport protein with both CAN and CaPLSase activities. Using a TMEM16F-deficient HEK293T cell line to avoid strong interference from endogenous CaPLSases, our functional characterization and mutagenesis studies revealed that Subdued is a bona fide CaPLSase. Our finding that Subdued is a moonlighting TMEM16 expands our understanding of the molecular mechanisms of TMEM16 proteins and their evolution and physiology in both Drosophila and humans.
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Affiliation(s)
- Trieu Le
- From the Departments of Biochemistry and
| | - Son C Le
- From the Departments of Biochemistry and
| | - Huanghe Yang
- From the Departments of Biochemistry and .,Neurobiology, Duke University Medical Center, Durham, North Carolina 27710
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234
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Davis HW, Vallabhapurapu SD, Chu Z, Vallabhapurapu SL, Franco RS, Mierzwa M, Kassing W, Barrett WL, Qi X. Enhanced phosphatidylserine-selective cancer therapy with irradiation and SapC-DOPS nanovesicles. Oncotarget 2019; 10:856-868. [PMID: 30783515 PMCID: PMC6368238 DOI: 10.18632/oncotarget.26615] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/29/2018] [Indexed: 02/06/2023] Open
Abstract
Normal living cells exhibit phosphatidylserine (PS) primarily within the intracellular leaflet of the plasma membrane. In contrast, viable cancer cells have high levels of PS on the external surface, and exhibit a broad range of surface PS, even within specific types of cancer. Agents that target surface PS have recently been developed to treat tumors and are expected to be more effective with higher surface PS levels. In this context, we examined whether surface PS is increased with irradiation. In vitro irradiation of cancer cell lines selected surviving cells that had higher surface PS in a dose- and time-dependent manner. This was more pronounced if surface PS was initially in the lower range for cancer cells. Radiation also increased the surface PS of tumor cells in subcutaneous xenografts in nude mice. We found an inverse relationship between steady state surface PS level of cancer cell lines and their sensitivity to radiation-induced cell death. In addition, serial irradiation, which selected surviving cells with higher surface PS, also increased resistance to radiation and to some chemotherapeutic drugs, suggesting a PS-dependent mechanism for development of resistance to therapy. On the other hand, fractionated radiation enhanced the effect of a novel anti-cancer, PS-targeting drug, SapC-DOPS, in some cancer cell lines. Our data suggest that we can group cancer cells into cells with low surface PS, which are sensitive to radiation, and high surface PS, which are sensitive to SapC-DOPS. Combination of these interventions may provide a potential new combination therapy.
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Affiliation(s)
- Harold W Davis
- Division of Hematology/Oncology, Translational Research Laboratory, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Subrahmanya D Vallabhapurapu
- Division of Hematology/Oncology, Translational Research Laboratory, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Zhengtao Chu
- Division of Hematology/Oncology, Translational Research Laboratory, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Swarajya L Vallabhapurapu
- Division of Hematology/Oncology, Translational Research Laboratory, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Robert S Franco
- Division of Hematology/Oncology, Translational Research Laboratory, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Michelle Mierzwa
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - William Kassing
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - William L Barrett
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Xiaoyang Qi
- Division of Hematology/Oncology, Translational Research Laboratory, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Division of Human Genetics, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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235
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Bricogne C, Fine M, Pereira PM, Sung J, Tijani M, Wang Y, Henriques R, Collins MK, Hilgemann DW. TMEM16F activation by Ca 2+ triggers plasma membrane expansion and directs PD-1 trafficking. Sci Rep 2019; 9:619. [PMID: 30679690 PMCID: PMC6345885 DOI: 10.1038/s41598-018-37056-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/03/2018] [Indexed: 12/22/2022] Open
Abstract
TMEM16F is a Ca2+ -gated ion channel that is required for Ca2+ -activated phosphatidylserine exposure on the surface of many eukaryotic cells. TMEM16F is widely expressed and has roles in platelet activation during blood clotting, bone formation and T cell activation. By combining microscopy and patch clamp recording we demonstrate that activation of TMEM16F by Ca2+ ionophores in Jurkat T cells triggers large-scale surface membrane expansion in parallel with phospholipid scrambling. With continued ionophore application,TMEM16F-expressing cells then undergo extensive shedding of ectosomes. The T cell co-receptor PD-1 is selectively incorporated into ectosomes. This selectivity depends on its transmembrane sequence. Surprisingly, cells lacking TMEM16F not only fail to expand surface membrane in response to elevated cytoplasmic Ca2+, but instead undergo rapid massive endocytosis with PD-1 internalisation. These results establish a new role for TMEM16F as a regulator of Ca2+ activated membrane trafficking.
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Affiliation(s)
| | - Michael Fine
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, Texas, USA
| | - Pedro M Pereira
- MRC Laboratory for Molecular Cell Biology, University College London, Gower St, London, UK
| | - Julia Sung
- National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Herts, UK
| | - Maha Tijani
- National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Herts, UK
| | - Youxue Wang
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, Texas, USA
| | - Ricardo Henriques
- MRC Laboratory for Molecular Cell Biology, University College London, Gower St, London, UK
| | - Mary K Collins
- UCL Cancer Institute, University College London, Gower St, London, UK.
- National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Herts, UK.
- Okinawa Institute of Science and Technology, Onna-son, Okinawa, Japan.
| | - Donald W Hilgemann
- University of Texas Southwestern Medical Center, Department of Physiology, Dallas, Texas, USA.
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236
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Nguyen DM, Chen LS, Yu WP, Chen TY. Comparison of ion transport determinants between a TMEM16 chloride channel and phospholipid scramblase. J Gen Physiol 2019; 151:518-531. [PMID: 30670476 PMCID: PMC6445582 DOI: 10.1085/jgp.201812270] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/02/2019] [Indexed: 01/03/2023] Open
Abstract
The I-V relation of the TMEM16A channel is linear, whereas that of the TMEM16F scramblase is outwardly rectifying. Nguyen et al. show that rectification of TMEM16A is regulated by the charge of residue 584 but that rectification of TMEM16F is affected by aromatic residues at the equivalent position. Two TMEM16 family members, TMEM16A and TMEM16F, have different ion transport properties. Upon activation by intracellular Ca2+, TMEM16A—a Ca2+-activated Cl− channel—is more selective for anions than cations, whereas TMEM16F—a phospholipid scramblase—appears to transport both cations and anions. Under saturating Ca2+ conditions, the current–voltage (I-V) relationships of these two proteins also differ; the I-V curve of TMEM16A is linear, while that of TMEM16F is outwardly rectifying. We previously found that mutating a positively charged lysine residue (K584) in the ion transport pathway to glutamine converted the linear I-V curve of TMEM16A to an outwardly rectifying curve. Interestingly, the corresponding residue in the outwardly rectifying TMEM16F is also a glutamine (Q559). Here, we examine the ion transport functions of TMEM16 molecules and compare the roles of K584 of TMEM16A and Q559 of TMEM16F in controlling the rectification of their respective I-V curves. We find that rectification of TMEM16A is regulated electrostatically by the side-chain charge on the residue at position 584, whereas the charge on residue 559 in TMEM16F has little effect. Unexpectedly, mutation of Q559 to aromatic amino acid residues significantly alters outward rectification in TMEM16F. These same mutants show reduced Ca2+-induced current rundown (or desensitization) compared with wild-type TMEM16F. A mutant that removes the rundown of TMEM16F could facilitate the study of ion transport mechanisms in this phospholipid scramblase in the same way that a CLC-0 mutant in which inactivation (or closure of the slow gate) is suppressed was used in our previous studies.
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Affiliation(s)
- Dung M Nguyen
- Graduate Group of Pharmacology and Toxicology, University of California, Davis, Davis, CA
| | - Louisa S Chen
- Center for Neuroscience, University of California, Davis, Davis, CA
| | - Wei-Ping Yu
- Center for Neuroscience, University of California, Davis, Davis, CA
| | - Tsung-Yu Chen
- Center for Neuroscience, University of California, Davis, Davis, CA .,Department of Neurology, University of California, Davis, Davis, CA
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237
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Han TW, Ye W, Bethel NP, Zubia M, Kim A, Li KH, Burlingame AL, Grabe M, Jan YN, Jan LY. Chemically induced vesiculation as a platform for studying TMEM16F activity. Proc Natl Acad Sci U S A 2019; 116:1309-1318. [PMID: 30622179 PMCID: PMC6347726 DOI: 10.1073/pnas.1817498116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Calcium-activated phospholipid scramblase mediates the energy-independent bidirectional translocation of lipids across the bilayer, leading to transient or, in the case of apoptotic scrambling, sustained collapse of membrane asymmetry. Cells lacking TMEM16F-dependent lipid scrambling activity are deficient in generation of extracellular vesicles (EVs) that shed from the plasma membrane in a Ca2+-dependent manner, namely microvesicles. We have adapted chemical induction of giant plasma membrane vesicles (GPMVs), which require both TMEM16F-dependent phospholipid scrambling and calcium influx, as a kinetic assay to investigate the mechanism of TMEM16F activity. Using the GPMV assay, we identify and characterize both inactivating and activating mutants that elucidate the mechanism for TMEM16F activation and facilitate further investigation of TMEM16F-mediated lipid translocation and its role in extracellular vesiculation.
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Affiliation(s)
- Tina W Han
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Wenlei Ye
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Neville P Bethel
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94143
| | - Mario Zubia
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Andrew Kim
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Kathy H Li
- Mass Spectrometry Facility, University of California, San Francisco, CA 94143
| | - Alma L Burlingame
- Mass Spectrometry Facility, University of California, San Francisco, CA 94143
| | - Michael Grabe
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94143
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Lily Y Jan
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143;
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
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238
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Falzone ME, Rheinberger J, Lee BC, Peyear T, Sasset L, Raczkowski AM, Eng ET, Di Lorenzo A, Andersen OS, Nimigean CM, Accardi A. Structural basis of Ca 2+-dependent activation and lipid transport by a TMEM16 scramblase. eLife 2019; 8:e43229. [PMID: 30648972 PMCID: PMC6355197 DOI: 10.7554/elife.43229] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/02/2019] [Indexed: 12/21/2022] Open
Abstract
The lipid distribution of plasma membranes of eukaryotic cells is asymmetric and phospholipid scramblases disrupt this asymmetry by mediating the rapid, nonselective transport of lipids down their concentration gradients. As a result, phosphatidylserine is exposed to the outer leaflet of membrane, an important step in extracellular signaling networks controlling processes such as apoptosis, blood coagulation, membrane fusion and repair. Several TMEM16 family members have been identified as Ca2+-activated scramblases, but the mechanisms underlying their Ca2+-dependent gating and their effects on the surrounding lipid bilayer remain poorly understood. Here, we describe three high-resolution cryo-electron microscopy structures of a fungal scramblase from Aspergillus fumigatus, afTMEM16, reconstituted in lipid nanodiscs. These structures reveal that Ca2+-dependent activation of the scramblase entails global rearrangement of the transmembrane and cytosolic domains. These structures, together with functional experiments, suggest that activation of the protein thins the membrane near the transport pathway to facilitate rapid transbilayer lipid movement.
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Affiliation(s)
- Maria E Falzone
- Department of BiochemistryWeill Cornell Medical CollegeNew YorkUnited States
| | - Jan Rheinberger
- Department of AnesthesiologyWeill Cornell Medical CollegeNew YorkUnited States
| | - Byoung-Cheol Lee
- Department of AnesthesiologyWeill Cornell Medical CollegeNew YorkUnited States
- Department of Structure and Function on Neural NetworkKorea Brain Research InstituteDeaguRepublic of Korea
| | - Thasin Peyear
- Department of Physiology and BiophysicsWeill Cornell Medical CollegeNew YorkUnited States
| | - Linda Sasset
- Department of PathologyWeill Cornell Medical CollegeNew YorkUnited States
| | - Ashleigh M Raczkowski
- Simons Electron Microscopy CenterNew York Structural Biology CenterNew YorkUnited States
| | - Edward T Eng
- Simons Electron Microscopy CenterNew York Structural Biology CenterNew YorkUnited States
| | | | - Olaf S Andersen
- Department of Physiology and BiophysicsWeill Cornell Medical CollegeNew YorkUnited States
| | - Crina M Nimigean
- Department of BiochemistryWeill Cornell Medical CollegeNew YorkUnited States
- Department of AnesthesiologyWeill Cornell Medical CollegeNew YorkUnited States
- Department of Physiology and BiophysicsWeill Cornell Medical CollegeNew YorkUnited States
| | - Alessio Accardi
- Department of BiochemistryWeill Cornell Medical CollegeNew YorkUnited States
- Department of AnesthesiologyWeill Cornell Medical CollegeNew YorkUnited States
- Department of Physiology and BiophysicsWeill Cornell Medical CollegeNew YorkUnited States
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239
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Taylor J, Bebawy M. Proteins Regulating Microvesicle Biogenesis and Multidrug Resistance in Cancer. Proteomics 2019; 19:e1800165. [PMID: 30520565 DOI: 10.1002/pmic.201800165] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 12/02/2018] [Indexed: 01/01/2023]
Abstract
Microvesicles (MV) are emerging as important mediators of intercellular communication. While MVs are important signaling vectors for many physiological processes, they are also implicated in cancer pathology and progression. Cellular activation is perhaps the most widely reported initiator of MV biogenesis, however, the precise mechanism remains undefined. Uncovering the proteins involved in regulating MV biogenesis is of interest given their role in the dissemination of deleterious cancer traits. MVs shed from drug-resistant cancer cells transfer multidrug resistance (MDR) proteins to drug-sensitive cells and confer the MDR phenotype in a matter of hours. MDR is attributed to the overexpression of ABC transporters, primarily P-glycoprotein and MRP1. Their expression and functionality is dependent on a number of proteins. In particular, FERM domain proteins have been implicated in supporting the functionality of efflux transporters in drug-resistant cells and in recipient cells during intercellular transfer by vesicles. Herein, the most recent research on the proteins involved in MV biogenesis and in the dissemination of MV-mediated MDR are discussed. Attention is drawn to unanswered questions in the literature that may prove to be of benefit in ongoing efforts to improve clinical response to chemotherapy and circumventing MDR.
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Affiliation(s)
- Jack Taylor
- Discipline of Pharmacy, Graduate School of Health, The University of Technology Sydney, Sydney, Australia
| | - Mary Bebawy
- Discipline of Pharmacy, Graduate School of Health, The University of Technology Sydney, Sydney, Australia
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240
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Ashokkumar P, Ashoka AH, Collot M, Das A, Klymchenko AS. A fluorogenic BODIPY molecular rotor as an apoptosis marker. Chem Commun (Camb) 2019; 55:6902-6905. [DOI: 10.1039/c9cc03242h] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Based on a BODIPY molecular rotor, we designed a probe that lights up its green fluorescence in apoptotic cells and distinguishes between early and late apoptosis.
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Affiliation(s)
- Pichandi Ashokkumar
- Laboratoire de Bioimagerie et Pathologies
- UMR 7021 CNRS
- Faculté de Pharmacie
- Université de Strasbourg
- Strasbourg CS 60024
| | - Anila Hoskere Ashoka
- Laboratoire de Bioimagerie et Pathologies
- UMR 7021 CNRS
- Faculté de Pharmacie
- Université de Strasbourg
- Strasbourg CS 60024
| | - Mayeul Collot
- Laboratoire de Bioimagerie et Pathologies
- UMR 7021 CNRS
- Faculté de Pharmacie
- Université de Strasbourg
- Strasbourg CS 60024
| | - Amitava Das
- CSIR-Central Salt & Marine Chemicals Research Institute
- Bhavnagar 364002
- India
| | - Andrey S. Klymchenko
- Laboratoire de Bioimagerie et Pathologies
- UMR 7021 CNRS
- Faculté de Pharmacie
- Université de Strasbourg
- Strasbourg CS 60024
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Gasecka A, Nieuwland R, Budnik M, Dignat-George F, Eyileten C, Harrison P, Huczek Z, Kapłon-Cieślicka A, Lacroix R, Opolski G, Pluta K, van der Pol E, Postuła M, Leroyer A, Siljander P, Sturk A, Filipiak KJ. Randomized controlled trial protocol to investigate the antiplatelet therapy effect on extracellular vesicles (AFFECT EV) in acute myocardial infarction. Platelets 2018; 31:26-32. [PMID: 30585111 DOI: 10.1080/09537104.2018.1557616] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Activated platelets contribute to thrombosis and inflammation by the release of extracellular vesicles (EVs) exposing P-selectin, phosphatidylserine (PS) and fibrinogen. P2Y12 receptor antagonists are routinely administered to inhibit platelet activation in patients after acute myocardial infarction (AMI), being a combined antithrombotic and anti-inflammatory therapy. The more potent P2Y12 antagonist ticagrelor improves cardiovascular outcome in patients after AMI compared to the less potent clopidogrel, suggesting that greater inhibition of platelet aggregation is associated with better prognosis. The effect of ticagrelor and clopidogrel on the release of EVs from platelets and other P2Y12-exposing cells is unknown. This study compares the effects of ticagrelor and clopidogrel on (1) the concentrations of EVs from activated platelets (primary end point), (2) the concentrations of EVs exposing fibrinogen, exposing PS, from leukocytes and from endothelial cells (secondary end points) and (3) the procoagulant activity of plasma EVs (tertiary end points) in 60 consecutive AMI patients. After the percutaneous coronary intervention, patients will be randomized to antiplatelet therapy with ticagrelor (study group) or clopidogrel (control group). Blood will be collected from patients at randomization, 48 hours after randomization and 6 months following the index hospitalization. In addition, 30 age- and gender-matched healthy volunteers will be enrolled in the study to investigate the physiological concentrations and procoagulant activity of EVs using recently standardized protocols and EV-dedicated flow cytometry. Concentrations of EVs will be determined by flow cytometry. Procoagulant activity of EVs will be determined by fibrin generation test. The compliance and response to antiplatelet therapy will be assessed by impedance aggregometry. We expect that plasma from patients treated with ticagrelor (1) contains lower concentrations of EVs from activated platelets, exposing fibrinogen, exposing PS, from leukocytes and from endothelial cells and (2) has lower procoagulant activity, when compared to patients treated with clopidogrel. Antiplatelet therapy effect on EVs may identify a new mechanism of action of ticagrelor, as well as create a basis for future studies to investigate whether lower EV concentrations are associated with improved clinical outcomes in patients treated with P2Y12 antagonists.
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Affiliation(s)
- Aleksandra Gasecka
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland.,Vesicle Observation Centre and Laboratory of Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Rienk Nieuwland
- Vesicle Observation Centre and Laboratory of Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Monika Budnik
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland
| | | | - Ceren Eyileten
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology, Warsaw, Poland
| | - Paul Harrison
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Zenon Huczek
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland
| | | | - Romaric Lacroix
- Aix Marseille University, INSERM, INRA, C2VN, Marseille, France
| | - Grzegorz Opolski
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland
| | - Kinga Pluta
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland
| | - Edwin van der Pol
- Vesicle Observation Centre and Laboratory of Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Biomedical Engineering & Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Marek Postuła
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology, Warsaw, Poland
| | - Aurélie Leroyer
- Aix Marseille University, INSERM, INRA, C2VN, Marseille, France
| | - Pia Siljander
- Division of Biochemistry and Biotechnology, Department of Biosciences, University of Helsinki, Helsinki, Finland.,Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Auguste Sturk
- Vesicle Observation Centre and Laboratory of Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Krzysztof J Filipiak
- 1st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland
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243
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AnnexinA5-pHrodo: a new molecular probe for measuring efferocytosis. Sci Rep 2018; 8:17731. [PMID: 30532026 PMCID: PMC6286334 DOI: 10.1038/s41598-018-35995-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/09/2018] [Indexed: 01/08/2023] Open
Abstract
Efferocytosis, the clearing of dead or dying cells from living tissues, is a highly programmed, vital process to maintain the healthy functioning of every organism. Disorders of efferocytosis have been linked to several chronic diseases including atherosclerosis and auto-immune diseases. To date several different assays to determine phagocytosis, using microscopy or FACS analysis with labelled targets, have been developed. However, many of these are unable to differentiate between cells that have truly been phagocytosed and those still present on the surface of the macrophages hindering exact assessment of efferocytotic capacity. We herein describe AnxA5-pHrodo and its negative control M1234-pHrodo as new molecular probes to measure in vitro as well as ex-vivo efferocytotic capacity.
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244
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Hallock MJ, Greenwood AI, Wang Y, Morrissey JH, Tajkhorshid E, Rienstra CM, Pogorelov TV. Calcium-Induced Lipid Nanocluster Structures: Sculpturing of the Plasma Membrane. Biochemistry 2018; 57:6897-6905. [PMID: 30456950 DOI: 10.1021/acs.biochem.8b01069] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The plasma membrane of the cell is a complex, tightly regulated, heterogeneous environment shaped by proteins, lipids, and small molecules. Ca2+ ions are important cellular messengers, spatially separated from anionic lipids. After cell injury, disease, or apoptotic events, anionic lipids are externalized to the outer leaflet of the plasma membrane and encounter Ca2+, resulting in dramatic changes in the plasma membrane structure and initiation of signaling cascades. Despite the high chemical and biological significance, the structures of lipid-Ca2+ nanoclusters are still not known. Previously, we demonstrated by solid-state nuclear magnetic resonance (NMR) spectroscopy that upon binding to Ca2+, individual phosphatidylserine lipids populate two distinct yet-to-be-characterized structural environments. Here, we concurrently employ extensive all-atom molecular dynamics (MD) simulations with our accelerated membrane mimetic and detailed NMR measurements to identify lipid-Ca2+ nanocluster conformations. We find that major structural characteristics of these nanoclusters, including interlipid pair distances and chemical shifts, agree with observable NMR parameters. Simulations reveal that lipid-ion nanoclusters are shaped by two characteristic, long-lived lipid structures induced by divalent Ca2+. Using ab initio quantum mechanical calculations of chemical shifts on MD-captured lipid-ion complexes, we show that computationally observed conformations are validated by experimental NMR data. Both NMR measurements of diluted specifically labeled lipids and MD simulations reveal that the basic structural unit that reshapes the membrane is a Ca2+-coordinated phosphatidylserine tetramer. Our combined computational and experimental approach presented here can be applied to other complex systems in which charged membrane-active molecular agents leave structural signatures on lipids.
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Affiliation(s)
- Michael J Hallock
- School of Chemical Sciences , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Alexander I Greenwood
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Yan Wang
- Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - James H Morrissey
- Department of Biological Chemistry , University of Michigan Medical School , Ann Arbor , Michigan 48103 , United States
| | - Emad Tajkhorshid
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Chad M Rienstra
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Taras V Pogorelov
- School of Chemical Sciences , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,National Center for Supercomputing Applications , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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245
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Shin HW, Takatsu H. Substrates of P4‐ATPases: beyond aminophospholipids (phosphatidylserine and phosphatidylethanolamine). FASEB J 2018; 33:3087-3096. [DOI: 10.1096/fj.201801873r] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hye-Won Shin
- Graduate School of Pharmaceutical SciencesKyoto University Kyoto Japan
| | - Hiroyuki Takatsu
- Graduate School of Pharmaceutical SciencesKyoto University Kyoto Japan
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246
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Asaro RJ, Zhu Q, Cabrales P. Erythrocyte Aging, Protection via Vesiculation: An Analysis Methodology via Oscillatory Flow. Front Physiol 2018; 9:1607. [PMID: 30505281 PMCID: PMC6250888 DOI: 10.3389/fphys.2018.01607] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/25/2018] [Indexed: 01/09/2023] Open
Abstract
We demonstrate that erythrocyte deformations, specifically of a type as occur in splenic flow (Zhu et al., 2017), and of the type that promote vesiculation can be caused by simple, yet tailored, oscillatory shear flow. We show that such oscillatory shear flow provides an ideal environment to explore a wide variety of metabolic and biochemical effects that promote erythrocyte vesiculation. Deformation details, typical of splenic flow, such as in-folding and implications for membrane/skeleton interaction are demonstrated and quantitatively analyzed. We introduce a theoretical, essentially analytical, vesiculation model that directly couples to our more complex numerical, multilevel, model that clearly delineates various fundamental elements, i.e., sub-processes, that are involved and mediate the vesiculation process. This analytical model highlights particulary important vesiculation precursors such as areas of membrane/skeleton disruptions that trigger the vesiculation process. We demonstrate, using flow cytometry, that the deformations we experimentally induce on cells, and numerically simulate, do not induce lethal forms of cell damage but do induce vesiculation as theoretically forecasted. This, we demonstrate, provides a direct link to cell membrane/skeletal damage such as is associated with metabolic and aging damage. An additional noteworthy feature of this approach is the avoidance of artificial devices, e.g., micro-fluidic chambers, in which deformations and their time scales are often unrepresentative of physiological processes such as splenic flow.
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Affiliation(s)
- Robert J. Asaro
- Department of Structural Engineering, University of California, San Diego, San Diego, CA, United States
| | - Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, San Diego, CA, United States
| | - Pedro Cabrales
- Biological Engineering, University of California, San Diego, La Jolla, CA, United States
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247
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Phosphatidylserine is a marker for axonal debris engulfment but its exposure can be decoupled from degeneration. Cell Death Dis 2018; 9:1116. [PMID: 30389906 PMCID: PMC6214901 DOI: 10.1038/s41419-018-1155-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/25/2018] [Accepted: 10/08/2018] [Indexed: 02/08/2023]
Abstract
Apoptotic cells expose Phosphatidylserine (PS), that serves as an “eat me” signal for engulfing cells. Previous studies have shown that PS also marks degenerating axonsduring developmental pruning or in response to insults (Wallerian degeneration), but the pathways that control PS exposure on degenerating axons are largely unknown. Here, we used a series of in vitro assays to systematically explore the regulation of PS exposure during axonal degeneration. Our results show that PS exposure is regulated by the upstream activators of axonal pruning and Wallerian degeneration. However, our investigation of signaling further downstream revealed divergence between axon degeneration and PS exposure. Importantly, elevation of the axonal energetic status hindered PS exposure, while inhibition of mitochondrial activity caused PS exposure, without degeneration. Overall, our results suggest that the levels of PS on the outer axonal membrane can be dissociated from the degeneration process and that the axonal energetic status plays a key role in the regulation of PS exposure.
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248
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Veit M, Koyro KI, Ahrens B, Bleibaum F, Munz M, Rövekamp H, Andrä J, Schreiber R, Kunzelmann K, Sommer A, Bhakdi S, Reiss K. Anoctamin-6 regulates ADAM sheddase function. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2018; 1865:1598-1610. [PMID: 30327201 DOI: 10.1016/j.bbamcr.2018.08.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 08/17/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
ADAM17, a prominent member of the "Disintegrin and Metalloproteinase" (ADAM) family, controls vital cellular functions through cleavage of transmembrane substrates including TGF-alpha, Amphiregulin (AREG) and TNF-Receptor 1 (TNFR1). We recently presented evidence that surface exposure of phosphatidylserine (PS) is pivotal for ADAM17 to exert sheddase activity. Anoctamin-6 (ANO6) has Ca2+-dependent phospholipid scramblase activity and it followed that the functions of ANO6 and ADAM17 might be linked. We report that overexpression of ANO6 in HEK293T cells led to increased Ca2+-mediated PS-exposure that was indeed accompanied by enhanced release of AREG and TGF-alpha. The effect was not observed when cells were treated with the PKC-dependent ADAM17 activator PMA. Transformation of cells with a constitutively active ANO6 mutant led to spontaneous PS-exposure and to the release of ADAM17-substrates in the absence of any stimuli. Inhibitor experiments indicated that ANO6-mediated enhancement of substrate cleavage simultaneously broadened the spectrum of participating metalloproteinases. In complementary experiments, siRNA-mediated downregulation of ANO6 was shown to decrease ionophore-mediated release of TNFR1 in human umbilical vein endothelial cells (HUVECs). We conclude that ANO6, by virtue of its scramblase activity, may play a role as an important regulator of the ADAM-network in the plasma membrane.
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Affiliation(s)
- Martin Veit
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Björn Ahrens
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Martin Munz
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Hagen Rövekamp
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Jörg Andrä
- Hamburg University of Applied Science, Ulmenliet 20, 21033 Hamburg, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Anselm Sommer
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Sucharit Bhakdi
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Karina Reiss
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany.
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249
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Phospholipid flippases enable precursor B cells to flee engulfment by macrophages. Proc Natl Acad Sci U S A 2018; 115:12212-12217. [PMID: 30355768 DOI: 10.1073/pnas.1814323115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
ATP11A and ATP11C, members of the P4-ATPases, are flippases that translocate phosphatidylserine (PtdSer) from the outer to inner leaflet of the plasma membrane. Using the W3 T lymphoma cell line, we found that Ca2+ ionophore-induced phospholipid scrambling caused prolonged PtdSer exposure in cells lacking both the ATP11A and ATP11C genes. ATP11C-null (ATP11C -/y ) mutant mice exhibit severe B-cell deficiency. In wild-type mice, ATP11C was expressed at all B-cell developmental stages, while ATP11A was not expressed after pro-B-cell stages, indicating that ATP11C -/y early B-cell progenitors lacked plasma membrane flippases. The receptor kinases MerTK and Axl are known to be essential for the PtdSer-mediated engulfment of apoptotic cells by macrophages. MerTK -/- and Axl -/- double deficiency fully rescued the lymphopenia in the ATP11C -/y bone marrow. Many of the rescued ATP11C -/y pre-B and immature B cells exposed PtdSer, and these cells were engulfed alive by wild-type peritoneal macrophages, in a PtdSer-dependent manner. These results indicate that ATP11A and ATP11C in precursor B cells are essential for rapidly internalizing PtdSer from the cell surface to prevent the cells' engulfment by macrophages.
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250
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Whitlock JM, Yu K, Cui YY, Hartzell HC. Anoctamin 5/TMEM16E facilitates muscle precursor cell fusion. J Gen Physiol 2018; 150:1498-1509. [PMID: 30257928 PMCID: PMC6219693 DOI: 10.1085/jgp.201812097] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 08/12/2018] [Accepted: 09/10/2018] [Indexed: 12/19/2022] Open
Abstract
Limb-girdle muscular dystrophy type 2L arises from mutations in the anoctamin ANO5, whose role in muscle physiology is unknown. Whitlock et al. show that loss of ANO5 perturbs phosphatidylserine exposure and cell–cell fusion in muscle precursor cells, which is an essential step in muscle repair. Limb-girdle muscular dystrophy type 2L (LGMD2L) is a myopathy arising from mutations in ANO5; however, information about the contribution of ANO5 to muscle physiology is lacking. To explain the role of ANO5 in LGMD2L, we previously hypothesized that ANO5-mediated phospholipid scrambling facilitates cell–cell fusion of mononucleated muscle progenitor cells (MPCs), which is required for muscle repair. Here, we show that heterologous overexpression of ANO5 confers Ca2+-dependent phospholipid scrambling to HEK-293 cells and that scrambling is associated with the simultaneous development of a nonselective ionic current. MPCs isolated from adult Ano5−/− mice exhibit defective cell fusion in culture and produce muscle fibers with significantly fewer nuclei compared with controls. This defective fusion is associated with a decrease of Ca2+-dependent phosphatidylserine exposure on the surface of Ano5−/− MPCs and a decrease in the amplitude of Ca2+-dependent outwardly rectifying ionic currents. Viral introduction of ANO5 in Ano5−/− MPCs restores MPC fusion competence, ANO5-dependent phospholipid scrambling, and Ca2+-dependent outwardly rectifying ionic currents. ANO5-rescued MPCs produce myotubes having numbers of nuclei similar to wild-type controls. These data suggest that ANO5-mediated phospholipid scrambling or ionic currents play an important role in muscle repair.
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Affiliation(s)
- Jarred M Whitlock
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
| | - Kuai Yu
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
| | - Yuan Yuan Cui
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
| | - H Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA
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