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The Molecular Mechanisms of Defective Copper Metabolism in Diabetic Cardiomyopathy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5418376. [PMID: 36238639 PMCID: PMC9553361 DOI: 10.1155/2022/5418376] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/22/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022]
Abstract
Copper is an essential trace metal element that significantly affects human physiology and pathology by regulating various important biological processes, including mitochondrial oxidative phosphorylation, connective tissue crosslinking, and antioxidant defense. Copper level has been proved to be closely related to the morbidity and mortality of cardiovascular diseases such as atherosclerosis, heart failure, and diabetic cardiomyopathy (DCM). Copper deficiency can induce cardiac hypertrophy and aggravate cardiomyopathy, while copper excess can mediate various types of cell death, such as autophagy, apoptosis, cuproptosis, pyroptosis, and cardiac hypertrophy and fibrosis. Both copper excess and copper deficiency lead to redox imbalance, activate inflammatory response, and aggravate diabetic cardiomyopathy. This defective copper metabolism suggests a specific metabolic pattern of copper in diabetes and a specific role in the pathogenesis and progression of DCM. This review is aimed at providing a timely summary of the effects of defective copper homeostasis on DCM and discussing potential underlying molecular mechanisms.
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Zhu Y, Schrecke S, Tang S, Odenkirk MT, Walker T, Stover L, Lyu J, Zhang T, Russell D, Baker ES, Yan X, Laganowsky A. Cupric Ions Selectively Modulate TRAAK-Phosphatidylserine Interactions. J Am Chem Soc 2022; 144:7048-7053. [PMID: 35421309 DOI: 10.1021/jacs.2c00612] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
TRAAK and TREK2 are two-pore domain K+ (K2P) channels and are modulated by diverse factors including temperature, membrane stretching, and lipids, such as phosphatidic acid. In addition, copper and zinc, both of which are essential for life, are known to regulate TREK2 and a number of other ion channels. However, the role of ions in the association of lipids with integral membrane proteins is poorly understood. Here, we discover cupric ions selectively modulate the binding of phosphatidylserine (PS) to TRAAK but not TREK2. Other divalent cations (Ca2+, Mg2+, and Zn2+) bind both channels but have no impact on binding PS and other lipids. Additionally, TRAAK binds more avidly to Cu2+ and Zn2+ than TREK2. In the presence of Cu2+, TRAAK binds similarly to PS with different acyl chains, indicating a crucial role of the serine headgroup in coordinating Cu2+. High-resolution native mass spectrometry (MS) enables the determination of equilibrium binding constants for distinct Cu2+-bound stoichiometries and uncovered the highest coupling factor corresponds to a 1:1 PS-to-Cu2+ ratio. Interestingly, the next three highest coupling factors had a ∼1.5:1 PS-to-Cu2+ ratio. Our findings bring forth the role of cupric ions as an essential cofactor in selective TRAAK-PS interactions.
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Affiliation(s)
- Yun Zhu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Samantha Schrecke
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Shuli Tang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Melanie T Odenkirk
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Thomas Walker
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Lauren Stover
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jixing Lyu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Tianqi Zhang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Erin S Baker
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Xin Yan
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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Lee S, Roesel D, Roke S. Imaging Cu 2+ binding to charged phospholipid membranes by high-throughput second harmonic wide-field microscopy. J Chem Phys 2021; 155:184704. [PMID: 34773948 DOI: 10.1063/5.0063362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The interaction of divalent copper ions (Cu2+) with cell membranes is crucial for a variety of physiological processes of cells, such as hormone synthesis and cellular energy production. These interactions would not be possible without membrane hydration. However, the role of water has not received a lot of attention in membrane studies. Here, we use high-throughput wide-field second harmonic (SH) microscopy to study the interaction between Cu2+ and hydrated freestanding Montal-Müller lipid membranes. The symmetric lipid membranes are composed of 1,2-diphytanoyl-sn-glycero-3-phosphocholine and either 1,2-diphytanoyl-sn-glycero-3-phosphate or 1,2-diphytanoyl-sn-glycero-3-phospho L-serine and are brought into contact with divalent Cu2+, which are added to one leaflet while maintaining the ionic strength balance. We observe transient domains of high SH intensity. In these areas, Cu2+ ions bind to the charged head groups, leading to charge neutralization on one side of the membrane. This exposes the ordered water at the non-interacting side of the membrane interface, which can be used to compute the interfacial membrane potential difference. We find that the domains of lipids with phosphatidic acid head groups display a higher interfacial membrane potential than those with phosphatidylserine head groups, which converts into higher dynamic electrostatic free energies and binding constants.
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Affiliation(s)
- Seonwoo Lee
- Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - David Roesel
- Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sylvie Roke
- Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Poyton MF, Pullanchery S, Sun S, Yang T, Cremer PS. Zn 2+ Binds to Phosphatidylserine and Induces Membrane Blebbing. J Am Chem Soc 2020; 142:18679-18686. [PMID: 33078929 DOI: 10.1021/jacs.0c09103] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Herein, we show that Zn2+ binds to phosphatidylserine (PS) lipids in supported lipid bilayers (SLBs), forming a PS-Zn2+ complex with an equilibrium dissociation constant of ∼100 μM. Significantly, Zn2+ binding to SLBs containing more than 10 mol % PS induces extensive reordering of the bilayer. This reordering is manifest through bright spots of high fluorescence intensity that can be observed when the bilayer contains a dye-labeled lipid. Measurements using atomic force microscopy (AFM) reveal that these spots represent three-dimensional unilamellar blebs. Bleb formation is ion specific, inducible by exposing the bilayer to μM concentrations of Zn2+ but not Mg2+, Cu2+, Co2+, or Mn2+. Moreover, Ca2+ can induce some blebbing at mM concentrations but not nearly as effectively as Zn2+. The interactions of divalent metal cations with PS lipids were further investigated by a combination of vibrational sum frequency spectroscopy (VSFS) and surface pressure-area isotherm measurements. VSFS revealed that Zn2+ and Ca2+ were bound to the phosphate and carboxylate moieties on PS via contact ion pairing, dehydrating the lipid headgroup, whereas Mg2+ and Cu2+ were bound without perturbing the hydration of these functional groups. Additionally, Zn2+ was found to dramatically reduce the area per lipid in lipid monolayers, while Mg2+ and Cu2+ did not. Ca2+ could also reduce the area per lipid but only when significantly higher surface pressures were applied. These measurements suggest that Zn2+ caused lipid blebbing by decreasing the area per lipid on the side of the bilayer to which the salt was exposed. Such findings have implications for blebbing, fusion, oxidation, and related properties of PS-rich membranes in biological systems where Zn2+ concentrations are asymmetrically distributed.
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Plasma Membrane MCC/Eisosome Domains Promote Stress Resistance in Fungi. Microbiol Mol Biol Rev 2020; 84:84/4/e00063-19. [PMID: 32938742 DOI: 10.1128/mmbr.00063-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
There is growing appreciation that the plasma membrane orchestrates a diverse array of functions by segregating different activities into specialized domains that vary in size, stability, and composition. Studies with the budding yeast Saccharomyces cerevisiae have identified a novel type of plasma membrane domain known as the MCC (membrane compartment of Can1)/eisosomes that correspond to stable furrows in the plasma membrane. MCC/eisosomes maintain proteins at the cell surface, such as nutrient transporters like the Can1 arginine symporter, by protecting them from endocytosis and degradation. Recent studies from several fungal species are now revealing new functional roles for MCC/eisosomes that enable cells to respond to a wide range of stressors, including changes in membrane tension, nutrition, cell wall integrity, oxidation, and copper toxicity. The different MCC/eisosome functions are often intertwined through the roles of these domains in lipid homeostasis, which is important for proper plasma membrane architecture and cell signaling. Therefore, this review will emphasize the emerging models that explain how MCC/eisosomes act as hubs to coordinate cellular responses to stress. The importance of MCC/eisosomes is underscored by their roles in virulence for fungal pathogens of plants, animals, and humans, which also highlights the potential of these domains to act as novel therapeutic targets.
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Baxter AJ, Santiago-Ruiz AN, Yang T, Cremer PS. Modulation of Cu 2+ Binding to Sphingosine-1-Phosphate by Lipid Charge. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:824-830. [PMID: 30638371 DOI: 10.1021/acs.langmuir.8b03718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite that is thought to participate in the regulation of many physiological processes and may play a key role in several diseases. Herein, we found that Cu2+ binds tightly to supported lipid bilayers (SLBs) containing S1P. Specifically, we demonstrated via fluorescence assays that Cu2+-S1P binding was bivalent and sensitive to the concentration of S1P in the SLB. In fact, the apparent equilibrium dissociation constant, KDApp, tightened by a factor of 132 from 4.5 μM to 34 nM as the S1P density was increased from 5.0 to 20 mol %. A major driving force for this apparent tightening was the more negative surface potential with increasing S1P concentration. This potential remained unaltered upon Cu2+ binding at pH 7.4 because two protons were released for every Cu2+ that bound. At pH 5.4, however, Cu2+ could not outcompete protons for the amine and no binding occurred. Moreover, at pH 9.4, the amine was partially deprotonated before Cu2+ binding and the surface potential became more positive on binding. The results for Cu2+-S1P binding were reminiscent of those for Cu2+-phosphatidylserine binding, where a carboxylate group helped to deprotonate the amine. In the case of S1P, however, the phosphate needed to bear two negative charges to facilitate amine deprotonation in the presence of Cu2+.
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Affiliation(s)
| | - Adriana N Santiago-Ruiz
- Department of Chemistry , The University of Puerto Rico , Cayey , Puerto Rico 00736 , United States
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Douglas LM, Konopka JB. Plasma membrane architecture protects Candida albicans from killing by copper. PLoS Genet 2019; 15:e1007911. [PMID: 30633741 PMCID: PMC6345494 DOI: 10.1371/journal.pgen.1007911] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 01/24/2019] [Accepted: 12/20/2018] [Indexed: 12/21/2022] Open
Abstract
The ability to resist copper toxicity is important for microbial pathogens to survive attack by innate immune cells. A sur7Δ mutant of the fungal pathogen Candida albicans exhibits decreased virulence that correlates with increased sensitivity to copper, as well as defects in other stress responses and morphogenesis. Previous studies indicated that copper kills sur7Δ cells by a mechanism distinct from the known resistance pathways involving the Crp1 copper exporter or the Cup1 metallothionein. Since Sur7 resides in punctate plasma membrane domains known as MCC/eisosomes, we examined overexpression of SUR7 and found that it rescued the copper sensitivity of a mutant that fails to form MCC/eisosomes (pil1Δ lsp1Δ), indicating that these domains act to facilitate Sur7 function. Genetic screening identified new copper-sensitive mutants, the strongest of which were similar to sur7Δ in having altered plasma membranes due to defects in membrane trafficking, cortical actin, and morphogenesis (rvs161Δ, rvs167Δ, and arp2Δ arp3Δ). Consistent with the mutants having altered plasma membrane organization, they were all more readily permeabilized by copper, which is known to bind phosphatidylserine and phosphatidylethanolamine and cause membrane damage. Although these phospholipids are normally localized to the intracellular leaflet of the plasma membrane, their exposure on the surface of the copper-sensitive mutants was indicated by increased susceptibility to membrane damaging agents that bind to these phospholipids. Increased copper sensitivity was also detected for a drs2Δ mutant, which lacks a phospholipid flippase that is involved in maintaining phospholipid asymmetry. Copper binds phosphatidylserine with very high affinity, and deleting CHO1 to prevent phosphatidylserine synthesis rescued the copper sensitivity of sur7Δ cells, confirming a major role for phosphatidylserine in copper sensitivity. These results highlight how proper plasma membrane architecture protects fungal pathogens from copper and attack by the immune system, thereby opening up new avenues for therapeutic intervention. The transition metal copper is used by the innate immune system to attack microbial pathogens. To better understand how the human fungal pathogen Candida albicans resists this type of stress, we screened for mutants that were more susceptible to killing by copper. Interestingly, we identified a new class of copper-sensitive mutants whose plasma membranes are more readily permeabilized by copper. The common characteristic of these new copper-sensitive mutants is that they have an altered cell surface, which weakened their resistance to copper. These results help to explain the toxic effects of copper and suggest novel therapeutic strategies for fungal infections.
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Affiliation(s)
- Lois M. Douglas
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - James B. Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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Anomalous behavior of membrane fluidity caused by copper-copper bond coupled phospholipids. Sci Rep 2018; 8:14093. [PMID: 30237448 PMCID: PMC6148289 DOI: 10.1038/s41598-018-32322-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/17/2018] [Indexed: 11/09/2022] Open
Abstract
Membrane fluidity, essential for cell functions, is obviously affected by copper, but the molecular mechanism is poorly understood. Here, we unexpectedly observed that a decrease in phospholipid (PL) bilayer fluidity caused by Cu2+ was more significant than those by Zn2+ and Ca2+, while a comparable reduction occurred in the last two ions. This finding disagrees with the placement in the periodic table of Cu just next to Zn and far from Ca. The physical nature was revealed to be an anomalous attraction between Cu+ cations, as well as the induced motif of two phospholipids coupled by Cu-Cu bond (PL-diCu-PL). Namely, upon Cu2+ ion binding to a negatively charged phosphate group of lipid, Cu2+ was reduced to Cu+. The attraction of the cations then caused one Cu+ ion simultaneously binding to two lipids and another Cu+, resulting in the formation of PL-diCu-PL structure. In contrast, this attraction cannot occur in the cases of Zn and Ca ions. Remarkably, besides lipids, the phosphate group also widely exists in other biological molecules, including DNA, RNA, ADP and ATP. Our findings thus provide a new view for understanding the biological functions of copper and the mechanism underlying copper-related diseases, as well as lipid assembly.
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Liu Y, Liu J. Cu 2+-Directed Liposome Membrane Fusion, Positive-Stain Electron Microscopy, and Oxidation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7545-7553. [PMID: 29804456 DOI: 10.1021/acs.langmuir.8b00864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Natural lipid headgroups contain a few types of metal ligands, such as phosphate, amine, and serine, which interact with metal ions differently. Herein, we studied the binding between Cu2+ and liposomes with four types of headgroups: phosphocholine (PC), phosphoglycerol (PG), phosphoserine (PS), and cholinephosphate (CP). Using fluorescently headgroup-labeled liposomes, Cu2+ strongly quenched the CP and PS liposomes, whereas quenching of PC and PG was weaker. Dynamic light scattering indicated that all of the four liposomes aggregated at high Cu2+ concentrations, and ethylenediaminetetraacetic acid (EDTA) only restored the original size of the PC liposome, implying fusion of the other three types of liposomes. The leakage tests revealed that the integrity of PC liposomes was not affected by Cu2+, but the other three liposomes leaked. Under TEM, all of the liposomes show a positive-stain feature in the presence of Cu2+ and Cu2+-stained individual liposomes with a short incubation time (<1 min). The oxidative catalytic property of Cu2+ was also tested, and a tight binding by the PS liposome inhibited the activity of Cu2+. Finally, a model of interaction for each liposome was proposed, and each one has a different metal-binding and interaction mechanism.
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Affiliation(s)
- Yibo Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
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Liu Y, Liu J. Zn 2+ Induced Irreversible Aggregation, Stacking, and Leakage of Choline Phosphate Liposomes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:14472-14479. [PMID: 29178805 DOI: 10.1021/acs.langmuir.7b03209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The interaction between lipids and metal ions is important for metal sensing, cellular signal transduction, and oxidative lipid damage. While most previous work overlooked the phosphate group of lipids for metal binding, we herein highlight its importance. Phosphocholine (PC) and its headgroup inversed choline phosphate (CP) lipids were used to prepare liposomes. From dynamic light scattering (DLS), Zn2+ causes significant aggregation or fusion of the CP liposomes, but not PC liposomes. The size change induced by Zn2+ is not fully reversed by adding EDTA, implying liposome fusion induced by Zn2+. Isothermal titration calorimetry (ITC) shows that binding between Zn2+ and CP liposomes is endothermic with a Kd of 110 μM Zn2+, suggesting an entropy driven reaction likely due to the release of bound water. In comparison, no heat was detected by titrating Zn2+ into PC liposomes or Ca2+ into CP liposomes. Furthermore, Zn2+ causes a transient leakage of the CP liposomes, and further leakage is observed upon removing Zn2+ by EDTA. Transmission electron microscopy (TEM) with negative stained samples showed multilamellar CP lipid structures attributable to Zn2+ sandwiched between lipid bilayers, leading to a proposed reaction mechanism. This work provides an interesting system for studying metal interacting with terminal phosphate groups in liposomes, affecting the size, charge, and membrane integrity of the liposomes.
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Affiliation(s)
- Yibo Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
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Hsu SK, Chang ZJ, Chang SM. Fluorescent Determination of Copper(II) in Industrial Wastewater Using Thiol-Capped Cadmium Sulfide–Zinc Sulfide Quantum Dots as the Probe. ANAL LETT 2017. [DOI: 10.1080/00032719.2017.1338715] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Shu-Kang Hsu
- Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Zhao-Jun Chang
- Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Sue-Min Chang
- Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan
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