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Bairos JA, Njoku U, Zafar M, Akl MG, Li L, Parlakgul G, Arruda AP, Widenmaier SB. Sterol O-acyltransferase (SOAT/ACAT) activity is required to form cholesterol crystals in hepatocyte lipid droplets. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159512. [PMID: 38761895 DOI: 10.1016/j.bbalip.2024.159512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/12/2024] [Accepted: 05/14/2024] [Indexed: 05/20/2024]
Abstract
OBJECTIVE Excess cholesterol storage can induce the formation of cholesterol crystals in hepatocyte lipid droplets. Such crystals distinguish metabolic dysfunction associated steatohepatitis (MASH) from simple steatosis and may underlie its pathogenesis by causing cell damage that triggers liver inflammation. The mechanism linking cholesterol excess to its crystallization in lipid droplets is unclear. As cholesteryl esters localize to and accumulate in lipid droplets more readily than unesterified free cholesterol, we investigated whether cholesterol esterification by sterol O-acyltransferase (SOAT), also known as acyl co-A cholesterol acyltransferase (ACAT), is required for hepatocyte lipid droplet crystal formation. METHOD Cholesterol crystals were measured in cholesterol loaded Hep3B hepatocytes, RAW264.7 macrophages, and mouse liver using polarizing light microscopy. We examined the effect of blocking SOAT activity on crystal formation and compared these results to features of cholesterol metabolism and the progression to intracellular crystal deposits. RESULTS Cholesterol loading of Hep3B cells caused robust levels of lipid droplet localized crystal formation in a dose- and time-dependent manner. Co-treatment with SOAT inhibitors and genetic ablation of SOAT1 blocked crystal formation. SOAT inhibitor also blocked crystal formation in low density lipoprotein (LDL) treated Hep3B cells, acetylated LDL treated RAW 264.7 macrophages, and in the liver of mice genetically predisposed to hepatic cholesterol overload and in mice with cholesterol enriched diet-induced MASH. CONCLUSION SOAT1-mediated esterification may underlie cholesterol crystals associated with MASH by concentrating it in lipid droplets. These findings imply that inhibiting hepatocyte SOAT1 may be able to alleviate cholesterol associated MASH. Moreover, that either a lipid droplet localized cholesteryl ester hydrolase is required for cholesterol crystal formation, or the crystals are composed of cholesteryl ester.
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Affiliation(s)
- Jordan A Bairos
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Uche Njoku
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Maria Zafar
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - May G Akl
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Physiology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Lei Li
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Gunes Parlakgul
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA, USA
| | - Ana Paula Arruda
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA, USA; Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Scott B Widenmaier
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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2
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Kataoka-Hamai C. Triacylglycerol-droplet-induced bilayer spontaneous curvature in giant unilamellar vesicles. Biophys J 2024; 123:1857-1868. [PMID: 38822522 PMCID: PMC11267425 DOI: 10.1016/j.bpj.2024.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 04/05/2024] [Accepted: 05/29/2024] [Indexed: 06/03/2024] Open
Abstract
This study investigated the incorporation of triacylglycerol droplets in the bilayers of giant unilamellar vesicles (GUVs) using four triacylglycerols and four phosphatidylcholines by confocal laser scanning microscopy. The triacylglycerol droplets were incorporated between the monolayer leaflets of the GUVs. Among the spherical droplets protruding on only one side of the bilayers, the droplets bound to the outer leaflets outnumbered those bound to the inner leaflets. The more frequent droplet binding to the outer leaflet caused transbilayer asymmetry in the droplet surface density. A vesicle consisting of a single-bilayer spherical segment and a double-bilayer spherical segment was also observed. The yield of these vesicles was comparable with or higher than that of the droplet-incorporating GUVs for many of the phosphatidylcholine-triacylglycerol combinations. In a vesicle consisting of single-bilayer and double-bilayer segments, most of the triacylglycerol droplets were localized on the outermost membrane surface along the segment boundary and in the double-bilayer segment. To rationalize the formation of these vesicle structures, we propose that the transbilayer asymmetry in the droplet surface density induces spontaneous curvature of the bilayer, with the bilayer spontaneously bending away from the droplets. Energy calculations performed assuming the existence of spontaneous curvature of the bilayer corroborated the experimentally determined membrane shapes for the vesicles consisting of unilamellar and bilamellar regions.
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Affiliation(s)
- Chiho Kataoka-Hamai
- Research Center for Macromolecules and Biomaterials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan.
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3
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Yanagawa M, Shimobayashi SF. Multi-dimensional condensation of intracellular biomolecules. J Biochem 2024; 175:179-186. [PMID: 37993409 DOI: 10.1093/jb/mvad095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/09/2023] [Indexed: 11/24/2023] Open
Abstract
Liquid-liquid phase separation has been recognized as universal mechanisms in living cells for the formation of RNA-protein condensates and ordered lipid domains. These biomolecular condensates or domains nucleate, diffuse and interact with each other across physical dimensions to perform their biological functions. Here we summarize key features of biophysical principles underlying the multi-dimensional condensation of RNA-protein condensates and ordered lipid domains, which are related to nuclear transcription, and signaling on cell membranes. Uncovering physicochemical factors that govern the spatiotemporal coupling of those condensates presents a new avenue in their functions and associated human diseases.
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Affiliation(s)
- Masataka Yanagawa
- Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan
- Cellular Informatics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Shunsuke F Shimobayashi
- Department of Life Science Frontiers, Center for iPS Cell Research and Application, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
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4
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Nencini R, Regnier MLG, Backlund SM, Mantzari E, Dunn CD, Ollila OHS. Probing the dynamic landscape of peptides in molecular assemblies by synergized NMR experiments and MD simulations. Commun Chem 2024; 7:28. [PMID: 38351219 PMCID: PMC10864328 DOI: 10.1038/s42004-024-01115-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 01/25/2024] [Indexed: 02/16/2024] Open
Abstract
Peptides or proteins containing small biomolecular aggregates, such as micelles, bicelles, droplets and nanodiscs, are pivotal in many fields ranging from structural biology to pharmaceutics. Monitoring dynamics of such systems has been limited by the lack of experimental methods that could directly detect their fast (picosecond to nanosecond) timescale dynamics. Spin relaxation times from NMR experiments are sensitive to such motions, but their interpretation for biomolecular aggregates is not straightforward. Here we show that the dynamic landscape of peptide-containing molecular assemblies can be determined by a synergistic combination of solution state NMR experiments and molecular dynamics (MD) simulations. Solution state NMR experiments are straightforward to implement without an excessive amount of sample, while direct combination of spin relaxation data to MD simulations enables interpretation of dynamic landscapes of peptides and other aggregated molecules. To demonstrate this, we interpret NMR data from transmembrane, peripheral, and tail anchored peptides embedded in micelles. Our results indicate that peptides and detergent molecules do not rotate together as a rigid body, but peptides rotate in a viscous medium composed of detergent micelle. Spin relaxation times also provide indirect information on peptide conformational ensembles. This work gives new perspectives on peptide dynamics in complex biomolecular assemblies.
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Affiliation(s)
- Ricky Nencini
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | | | - Sofia M Backlund
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | | | - Cory D Dunn
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - O H Samuli Ollila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
- VTT Technical Research Centre of Finland, Espoo, Finland.
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5
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Henne WM. The (social) lives, deaths, and biophysical phases of lipid droplets. Curr Opin Cell Biol 2023; 82:102178. [PMID: 37295067 PMCID: PMC10782554 DOI: 10.1016/j.ceb.2023.102178] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023]
Abstract
Lipid droplets (LDs) are major lipid storage organelles, sequestering energy-rich triglycerides and serving as nutrient sinks for cellular homeostasis. Observed for over a century but generally ignored, LDs are now appreciated to play key roles in organismal physiology and disease. They also form numerous functional contacts with other organelles. Here, we highlight recent studies examining LDs from distinct perspectives of their life cycle: their biogenesis, "social" life as they interact with other organelles, and deaths via lipolysis or lipophagy. We also discuss recent work showing how changes in LD lipid content alter the biophysical phases of LD lipids, and how this may fine-tune the LD protein landscape and ultimately LD function.
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Affiliation(s)
- W Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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6
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Cholesterol esters form supercooled lipid droplets whose nucleation is facilitated by triacylglycerols. Nat Commun 2023; 14:915. [PMID: 36807572 PMCID: PMC9938224 DOI: 10.1038/s41467-023-36375-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 01/27/2023] [Indexed: 02/19/2023] Open
Abstract
Cellular cholesterol can be metabolized to its fatty acid esters, cholesteryl esters (CEs), to be stored in lipid droplets (LDs). With triacylglycerols (TGs), CEs represent the main neutral lipids in LDs. However, while TG melts at ~4 °C, CE melts at ~44 °C, raising the question of how CE-rich LDs form in cells. Here, we show that CE forms supercooled droplets when the CE concentration in LDs is above 20% to TG and, in particular, liquid-crystalline phases when the fraction of CEs is above 90% at 37 °C. In model bilayers, CEs condense and nucleate droplets when the CE/phospholipid ratio reaches over 10-15%. This concentration is reduced by TG pre-clusters in the membrane that thereby facilitate CE nucleation. Accordingly, blocking TG synthesis in cells is sufficient to strongly dampen CE LD nucleation. Finally, CE LDs emerged at seipins, which cluster and nucleate TG LDs in the ER. However, when TG synthesis is inhibited, similar numbers of LDs are generated in the presence and absence of seipin, suggesting that seipin controls CE LD formation via its TG clustering capacity. Our data point to a unique model whereby TG pre-clusters, favorable at seipins, catalyze the nucleation of CE LDs.
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7
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A liquid crystal world for the origins of life. Emerg Top Life Sci 2022; 6:557-569. [PMID: 36373852 DOI: 10.1042/etls20220081] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/23/2022] [Accepted: 10/27/2022] [Indexed: 11/16/2022]
Abstract
Nucleic acids (NAs) in modern biology accomplish a variety of tasks, and the emergence of primitive nucleic acids is broadly recognized as a crucial step for the emergence of life. While modern NAs have been optimized by evolution to accomplish various biological functions, such as catalysis or transmission of genetic information, primitive NAs could have emerged and been selected based on more rudimental chemical-physical properties, such as their propensity to self-assemble into supramolecular structures. One such supramolecular structure available to primitive NAs are liquid crystal (LC) phases, which are the outcome of the collective behavior of short DNA or RNA oligomers or monomers that self-assemble into linear aggregates by combinations of pairing and stacking. Formation of NA LCs could have provided many essential advantages for a primitive evolving system, including the selection of potential genetic polymers based on structure, protection by compartmentalization, elongation, and recombination by enhanced abiotic ligation. Here, we review recent studies on NA LC assembly, structure, and functions with potential prebiotic relevance. Finally, we discuss environmental or geological conditions on early Earth that could have promoted (or inhibited) primitive NA LC formation and highlight future investigation axes essential to further understanding of how LCs could have contributed to the emergence of life.
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Rogers S, Gui L, Kovalenko A, Zoni V, Carpentier M, Ramji K, Ben Mbarek K, Bacle A, Fuchs P, Campomanes P, Reetz E, Speer NO, Reynolds E, Thiam AR, Vanni S, Nicastro D, Henne WM. Triglyceride lipolysis triggers liquid crystalline phases in lipid droplets and alters the LD proteome. J Cell Biol 2022; 221:213472. [PMID: 36112368 PMCID: PMC9485706 DOI: 10.1083/jcb.202205053] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/10/2022] [Accepted: 08/22/2022] [Indexed: 01/08/2023] Open
Abstract
Lipid droplets (LDs) are reservoirs for triglycerides (TGs) and sterol-esters (SEs), but how these lipids are organized within LDs and influence their proteome remain unclear. Using in situ cryo-electron tomography, we show that glucose restriction triggers lipid phase transitions within LDs generating liquid crystalline lattices inside them. Mechanistically this requires TG lipolysis, which decreases the LD's TG:SE ratio, promoting SE transition to a liquid crystalline phase. Molecular dynamics simulations reveal TG depletion promotes spontaneous TG and SE demixing in LDs, additionally altering the lipid packing of the PL monolayer surface. Fluorescence imaging and proteomics further reveal that liquid crystalline phases are associated with selective remodeling of the LD proteome. Some canonical LD proteins, including Erg6, relocalize to the ER network, whereas others remain LD-associated. Model peptide LiveDrop also redistributes from LDs to the ER, suggesting liquid crystalline phases influence ER-LD interorganelle transport. Our data suggests glucose restriction drives TG mobilization, which alters the phase properties of LD lipids and selectively remodels the LD proteome.
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Affiliation(s)
- Sean Rogers
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Long Gui
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Anastasiia Kovalenko
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Valeria Zoni
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Maxime Carpentier
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Kamran Ramji
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Kalthoum Ben Mbarek
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Amelie Bacle
- Institute Jacques Monod, Centre national de la recherche scientifique, University of Paris, Paris, France
| | - Patrick Fuchs
- Laboratoire des Biomolécules, Paris, France.,Université de Paris, UFR Sciences du Vivant, Paris, France
| | - Pablo Campomanes
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Evan Reetz
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Natalie Ortiz Speer
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Emma Reynolds
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l'École Normale Supérieure, École normale supérieure, Université Paris Sciences et Lettres, Centre national de la recherche scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Stefano Vanni
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Daniela Nicastro
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - W Mike Henne
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
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Windham IA, Cohen S. Lipid droplets go through a (liquid crystalline) phase. J Cell Biol 2022; 221:e202210008. [PMID: 36264229 PMCID: PMC9587377 DOI: 10.1083/jcb.202210008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Lipid droplets (LDs) are key organelles for fat storage and trafficking. In this issue, Rogers et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202205053) show that glucose restriction triggers liquid crystalline lattice formation within LDs, which in turn alters the recruitment of proteins to the LD surface.
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Affiliation(s)
- Ian A. Windham
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Sarah Cohen
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC
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10
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Luo Z, Liu Y, Li H, Zhou Y, Peng Y, Lin X, Fang Y, Wan J, Wei B. Associations of PNPLA3 rs738409 Polymorphism with Plasma Lipid Levels: A Systematic Review and Meta-Analysis. Horm Metab Res 2022; 54:686-695. [PMID: 36206762 DOI: 10.1055/a-1929-1677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Accumulating evidence has shown that the rs738409 polymorphism of patatin-like phospholipase domain-containing 3 (PNPLA3) is associated with non-alcoholic fatty liver disease (NAFLD). Since NAFLD has been reported to be associated with lipid metabolism, this study is conducted to explore whether the rs738409 polymorphism of PNPLA3 was associated with lipid levels. By searching PubMed and the Cochrane database from May 31, 2020, to June 30, 2021. Sixty-three studies (81 003 subjects) were included for the analysis. The consistent findings for the associations of rs738409 polymorphism with lipid levels were the significantly decreased triglycerides (TG) (SMD=-0.04, 95% CI=-0.07 to -0.01, p=0.02) and total cholesterol (TC) (SMD=-0.03, 95% CI=-0.05 to -0.01, p<0.01) levels. Subgroup analysis indicated that the associations of rs738409 polymorphism with TG and TC levels were stronger in Caucasians, obesity patients, and adult subjects than in Asians, T2DM patients, and children subjects. The rs738409 polymorphism of PNPLA3 was associated with lower TG and TC levels in Caucasians, obese and adult subjects, which may contribute to the reduced coronary artery disease (CAD) risk between PNPLA3 rs738409 polymorphism and CAD.
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Affiliation(s)
- Zhi Luo
- Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yang Liu
- Endocrinology, China Resources and WISCO General Hospital, Wuhan, China
| | - Hang Li
- Geratology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yawen Zhou
- Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yuanyuan Peng
- Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xuan Lin
- Endocrinology, China Resources and WISCO General Hospital, Wuhan, China
| | - Ying Fang
- Endocrinology, China Resources and WISCO General Hospital, Wuhan, China
| | - Jing Wan
- Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, China
| | - Baozhu Wei
- Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, China
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11
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Kowert BA. Diffusion of Squalene in Nonaqueous Solvents. ACS OMEGA 2022; 7:31424-31430. [PMID: 36092635 PMCID: PMC9454272 DOI: 10.1021/acsomega.2c03842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Capillary flow techniques have been used to determine the translational diffusion constant, D, of squalene in seven alkanes and five cyclohexanes. The alkanes are n-hexane, n-octane, n-decane, n-dodecane, n-tetradecane, 2,2,4,4,6,8,8-heptamethylnonane (isocetane), and 2,6,10,14-tetramethylpentadecane (pristane). The cyclohexanes are cyclohexane, n-butylcyclohexane, n-hexylcyclohexane, n-octylcyclohexane, and n-dodecylcyclohexane. When combined with published data in CD2Cl2, ethyl acetate, n-hexadecane, squalane, n-octane-squalane mixtures, and supercritical CO2, the 35 diffusion constants and viscosities, η, vary by factors of ∼230 and ∼500, respectively. A fit to the modified Stokes-Einstein equation (MSE, D/T = A SE/η p ) gives an average absolute percentage difference (AAPD) of 7.72% between the experimental and calculated D values where p and A SE are constants, T is the absolute temperature, and the AAPD is the average value of (102) (|D calcd - D exptl|/D exptl). Two other MSE fits using subsets of the 35 diffusion constants may be useful for (a) estimating the viscosity of the hydrophobic core of lipid droplets, where squalene is a naturally occurring component, and (b) providing estimates of the D values needed to design extraction processes by which squalene is obtained from plant oils. The Wilke-Chang equation also was considered and found to give larger AAPDs than the corresponding MSE fits.
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Actis Dato V, Benitez-Amaro A, Garcia E, Claudi L, Lhoëst MTL, Iborra A, Escola-Gil JC, Guerra JM, Samouillan V, Enrich C, Chiabrando G, Llorente-Cortés V. Targeting cholesteryl ester accumulation in the heart improves cardiac insulin response. Biomed Pharmacother 2022; 152:113270. [PMID: 35709652 DOI: 10.1016/j.biopha.2022.113270] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/02/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Antibodies against the P3 sequence (Gly1127-Cys1140) of LRP1 (anti-P3 Abs) specifically block cholesteryl ester (CE) accumulation in vascular cells. LRP1 is a key regulator of insulin receptor (InsR) trafficking in different cell types. The link between CE accumulation and the insulin response are largely unknown. Here, the effects of P3 peptide immunization on the alterations induced by a high-fat diet (HFD) in cardiac insulin response were evaluated. METHODS Irrelevant (IrP)- or P3 peptide-immunized rabbits were randomized into groups fed either HFD or normal chow. Cardiac lipid content was characterized by thin-layer chromatography, confocal microscopy, and electron microscopy. LRP1, InsR and glucose transporter type 4 (GLUT4) levels were determined in membranes and total lysates from rabbit heart. The interaction between InsR and LRP1 was analyzed by immunoprecipitation and confocal microscopy. Insulin signaling activity and glucose uptake were evaluated in HL-1 cells exposed to rabbit serum from the different groups. FINDINGS HFD reduces cardiac InsR and GLUT4 membrane levels and the interactions between LRP1/InsR. Targeting the P3 sequence on LRP1 through anti-P3 Abs specifically reduces CE accumulation in the heart independently of changes in the circulating lipid profile. This restores InsR and GLUT4 levels in cardiac membranes as well as the LRP1/InsR interactions of HFD-fed rabbits. In addition, anti-P3 Abs restores the insulin signaling cascade and glucose uptake in HL-1 cells exposed to hypercholesterolemic rabbit serum. INTERPRETATION LRP1-immunotargeting can block CE accumulation within the heart with specificity, selectivity, and efficacy, thereby improving the cardiac insulin response; this has important therapeutic implications for a wide range of cardiac diseases. FUNDING Fundació MARATÓ TV3: grant 101521-10, Instiuto de Salud Carlos III (ISCIII) and ERDFPI18/01584, Fundación BBVA Ayudas a Equipos de Investigación 2019. SECyT-UNC grants PROYECTOS CONSOLIDAR 2018-2021; FONCyT, Préstamo BID PICT grant 2015-0807 and grant 2017-4497.
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Affiliation(s)
- Virginia Actis Dato
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Córdoba, Argentina
| | - Aleyda Benitez-Amaro
- Institute of Biomedical Research of Barcelona (IIBB)-Spanish National Research Council (CSIC), Barcelona, Spain; Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain
| | - Eduardo Garcia
- Institute of Biomedical Research of Barcelona (IIBB)-Spanish National Research Council (CSIC), Barcelona, Spain; Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain
| | - Lene Claudi
- Institute of Biomedical Research of Barcelona (IIBB)-Spanish National Research Council (CSIC), Barcelona, Spain; Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain
| | - Maria Teresa LaChica Lhoëst
- Institute of Biomedical Research of Barcelona (IIBB)-Spanish National Research Council (CSIC), Barcelona, Spain; Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain
| | - Antoni Iborra
- SCAC, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
| | - Joan Carles Escola-Gil
- Metabolic Basis of Cardiovascular Risk, Biomedical Research Institute Sant Pau (IIB Sant Pau), Hospital de la Santa Creu i Sant Pau. CIBER de Diabetes y enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona. Spain
| | - Jose Maria Guerra
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau (IIB Sant Pau), Universitat Autonoma de Barcelona, Barcelona, Spain; CIBERCV, Institute of Health Carlos III, 28029 Madrid, Spain
| | - Valerie Samouillan
- CIRIMAT, Université de Toulouse, Université Paul Sabatier, Equipe PHYPOL, 31062 Toulouse, France
| | - Carlos Enrich
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Gustavo Chiabrando
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Córdoba, Argentina.
| | - Vicenta Llorente-Cortés
- Institute of Biomedical Research of Barcelona (IIBB)-Spanish National Research Council (CSIC), Barcelona, Spain; Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain; CIBERCV, Institute of Health Carlos III, 28029 Madrid, Spain.
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Jung Y, Jin JH, Kim Y, Oh JH, Moon H, Jeong H, Kim J, Park YK, Oh Y, Park S, Kim D. Development of a fluorescent nanoprobe based on an amphiphilic single-benzene-based fluorophore for lipid droplet detection and its practical applications. Org Biomol Chem 2022; 20:5423-5433. [PMID: 35758412 DOI: 10.1039/d2ob00830k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lipid droplets (LDs) are crucial biological organelles connected with metabolic pathways in biological systems and diseases. To monitor the locations and accumulation of LDs in lipid-related diseases, the development of a visualization tool for LDs has gained importance. In particular, LD visualization using fluorescent probes has gained attention. Herein, a new fluorescent nanoprobe, BMeS-Ali, is developed that can sense LDs based on an amphiphilic single benzene-based fluorophore (SBBF). BMeS-Ali consists of hydrophilic (-NH2) and hydrophobic (-C12H25) moieties and exists as a micelle nanostructure in aqueous media. BMeS-Ali has a weak fluorescence, but its emission was dramatically enhanced upon exposure to the LD components such as oleic acids (OA) by reassembling its nano-formulation. BMeS-Ali showed a selective LD staining ability and great biocompatibility in cells (cancer cells and stem cells). It also showed a practical sensing ability towards biologically derived lipids and can be applied to the visualization of human fingerprints. We found that the nanoprobe BMeS-Ali has significant potential to serve as a practical dye and sensor for lipids, especially for LD imaging in the biomedical research area and broader industrial applications.
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Affiliation(s)
- Yuna Jung
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
| | - Ji Hye Jin
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
| | - Youngseo Kim
- Department of Chemistry, Korea University, Seoul, 02841, Republic of Korea
| | - Ji Hyeon Oh
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
| | - Heechang Moon
- Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea
| | - Huisu Jeong
- Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea
| | - Jaehoon Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
| | - Yoon Kyung Park
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea.
| | - Yohan Oh
- Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea.,Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Seoul 04763, Korea
| | - Sungnam Park
- Department of Chemistry, Korea University, Seoul, 02841, Republic of Korea
| | - Dokyoung Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea. .,Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, Kyung Hee University, Seoul 02447, Republic of Korea.,Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea.,Center for Converging Humanities, Kyung Hee University, Seoul 02447, Republic of Korea.,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, Republic of Korea
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14
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Kim S, Swanson JMJ, Voth GA. Computational Studies of Lipid Droplets. J Phys Chem B 2022; 126:2145-2154. [PMID: 35263109 PMCID: PMC8957551 DOI: 10.1021/acs.jpcb.2c00292] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/26/2022] [Indexed: 02/05/2023]
Abstract
Lipid droplets (LDs) are intracellular organelles whose primary function is energy storage. Known to emerge from the endoplasmic reticulum (ER) bilayer, LDs have a unique structure with a core consisting of neutral lipids, triacylglycerol (TG) or sterol esters (SE), surrounded by a phospholipid (PL) monolayer and decorated by proteins that come and go throughout their complex lifecycle. In this Feature Article, we review recent developments in computational studies of LDs, a rapidly growing area of research. We highlight how molecular dynamics (MD) simulations have provided valuable molecular-level insight into LD targeting and LD biogenesis. Additionally, we review the physical properties of TG from different force fields compared with experimental data. Possible future directions and challenges are discussed.
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Affiliation(s)
- Siyoung Kim
- Pritzker
School of Molecular Engineering, University
of Chicago, Chicago, Illinois 60637, United States
| | - Jessica M. J. Swanson
- Department
of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Gregory A. Voth
- Department
of Chemistry, Chicago Center for Theoretical Chemistry, James Franck
Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois 60637, United States
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15
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Jing Y, Liu G, Zhang C, Yu B, Sun J, Lin D, Qu J. Lipophilic Red-Emitting Carbon Dots for Detecting and Tracking Lipid Droplets in Live Cells. ACS APPLIED BIO MATERIALS 2022; 5:1187-1193. [PMID: 35195413 DOI: 10.1021/acsabm.1c01230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lipid droplets (LDs), a dynamic organelle, are of vital importance in regulating the storage of neutral lipids and energy homeostasis. The aberrant expression of LDs is found to be highly associated with diverse metabolic diseases. Thus, detecting and monitoring LDs are essential to study the pathological and physiological processes of LDs in living bodies. However, it remains challenging to obtain suitable imaging probes to track LDs in vivo. Fortunately, the emergence of carbon dots (CDs), which are fluorescent nanomaterials with good biocompatibility and high stability, has provided us an unprecedented choice. In this work, CDs were synthesized via a solvothermal treatment of commercial reagents, 3-dimethylaminophenol. Interestingly, the prepared CDs show an intense red emission in non-hydrogen-bonding solution and have strong LD-targeting ability without any postmodification of ligands. Moreover, due to their low phototoxicity and excellent photostability, CDs were successfully applied to track the dynamics of LDs in live cells and image LDs in different cell lines and lipid-rich tissues. Overall, this work here proposed an LD-specific red-emitting CD probe, which will be of great value for learning more about LD-associated behaviors and diseases.
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Affiliation(s)
- Yingying Jing
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Center for Biomedical Photonics, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Guoyong Liu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
| | - Chenshuang Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Center for Biomedical Photonics, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Bin Yu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Center for Biomedical Photonics, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jian Sun
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
| | - Danying Lin
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Center for Biomedical Photonics, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Junle Qu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Center for Biomedical Photonics, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
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16
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Butovich IA, Wilkerson A, Yuksel S. Depletion of Cholesteryl Esters Causes Meibomian Gland Dysfunction-Like Symptoms in a Soat1-Null Mouse Model. Int J Mol Sci 2021; 22:1583. [PMID: 33557318 PMCID: PMC7915537 DOI: 10.3390/ijms22041583] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 02/08/2023] Open
Abstract
Previous studies on ablation of several key genes of meibogenesis related to fatty acid elongation, omega oxidation, and esterification into wax esters have demonstrated that inactivation of any of them led to predicted changes in the meibum lipid profiles and caused severe abnormalities in the ocular surface and Meibomian gland (MG) physiology and morphology. In this study, we evaluated the effects of Soat1 ablation that were expected to cause depletion of the second largest class of Meibomian lipids (ML)-cholesteryl esters (CE)-in a mouse model. ML of the Soat1-null mice were examined using liquid chromatography high-resolution mass spectrometry and compared with those of Soat1+/- and wild-type mice. Complete suppression of CE biosynthesis and simultaneous accumulation of free cholesterol (Chl) were observed in Soat1-null mice, while Soat1+/- mutants had normal Chl and CE profiles. The total arrest of the CE biosynthesis in response to Soat1 ablation transformed Chl into the dominant lipid in meibum accounting for at least 30% of all ML. The Soat1-null mice had clear manifestations of dry eye and MG dysfunction. Enrichment of meibum with Chl and depletion of CE caused plugging of MG orifices, increased meibum rigidity and melting temperature, and led to a massive accumulation of lipid deposits around the eyes of Soat1-null mice. These findings illustrate the role of Soat1/SOAT1 in the lipid homeostasis and pathophysiology of MG.
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Affiliation(s)
- Igor A. Butovich
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA; (A.W.); (S.Y.)
- The Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA
| | - Amber Wilkerson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA; (A.W.); (S.Y.)
| | - Seher Yuksel
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA; (A.W.); (S.Y.)
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17
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Wang HY, Bharti D, Levental I. Membrane Heterogeneity Beyond the Plasma Membrane. Front Cell Dev Biol 2020; 8:580814. [PMID: 33330457 PMCID: PMC7710808 DOI: 10.3389/fcell.2020.580814] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/02/2020] [Indexed: 01/21/2023] Open
Abstract
The structure and organization of cellular membranes have received intense interest, particularly in investigations of the raft hypothesis. The vast majority of these investigations have focused on the plasma membrane of mammalian cells, yielding significant progress in understanding membrane heterogeneity in terms of lipid composition, molecular structure, dynamic regulation, and functional relevance. In contrast, investigations on lipid organization in other membrane systems have been comparatively scarce, despite the likely relevance of membrane domains in these contexts. In this review, we summarize recent observations on lipid organization in organellar membranes, including endoplasmic reticulum, Golgi, endo-lysosomes, lipid droplets, and secreted membranes like lung surfactant, milk fat globule membranes, and viral membranes. Across these non-plasma membrane systems, it seems that the biophysical principles underlying lipid self-organization contribute to lateral domains.
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Affiliation(s)
- Hong-Yin Wang
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
| | - Deepti Bharti
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
- National Institute of Technology, Rourkela, India
| | - Ilya Levental
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
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18
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Lipid Stores and Lipid Metabolism Associated Gene Expression in Porcine and Bovine Parthenogenetic Embryos Revealed by Fluorescent Staining and RNA-seq. Int J Mol Sci 2020; 21:ijms21186488. [PMID: 32899450 PMCID: PMC7555686 DOI: 10.3390/ijms21186488] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 12/27/2022] Open
Abstract
Compared to other mammalian species, porcine oocytes and embryos are characterized by large amounts of lipids stored mainly in the form of droplets in the cytoplasm. The amount and the morphology of lipid droplets (LD) change throughout the preimplantation development, however, relatively little is known about expression of genes involved in lipid metabolism of early embryos. We compared porcine and bovine blastocyst stage embryos as well as dissected inner cell mass (ICM) and trophoblast (TE) cell populations with regard to lipid droplet storage and expression of genes functionally annotated to selected lipid gene ontology terms using RNA-seq. Comparing the number and the volume occupied by LD between bovine and porcine blastocysts, we have found significant differences both at the level of single embryo and a single blastomere. Aside from different lipid content, we found that embryos regulate the lipid metabolism differentially at the gene expression level. Out of 125 genes, we found 73 to be differentially expressed between entire porcine and bovine blastocyst, and 36 and 51 to be divergent between ICM and TE cell lines. We noticed significant involvement of cholesterol and ganglioside metabolism in preimplantation embryos, as well as a possible shift towards glucose, rather than pyruvate dependence in bovine embryos. A number of genes like DGAT1, CD36 or NR1H3 may serve as lipid associated markers indicating distinct regulatory mechanisms, while upregulated PLIN2, APOA1, SOAT1 indicate significant function during blastocyst formation and cell differentiation in both models.
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