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Watanabe H, Hanashima S, Yano Y, Yasuda T, Murata M. Passive Translocation of Phospholipids in Asymmetric Model Membranes: Solid-State 1H NMR Characterization of Flip-Flop Kinetics Using Deuterated Sphingomyelin and Phosphatidylcholine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15189-15199. [PMID: 37729012 DOI: 10.1021/acs.langmuir.3c01650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Although lateral and inter-leaflet lipid-lipid interactions in cell membranes play roles in maintaining asymmetric lipid bilayers, the molecular basis of these interactions is largely unknown. Here, we established a method to determine the distribution ratio of phospholipids between the outer and inner leaflets of asymmetric large unilamellar vesicles (aLUVs). The trimethylammonium group, (CH3)3N+, in the choline headgroup of N-palmitoyl-sphingomyelin (PSM) and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) gave rise to a relatively sharp signal in magic-angle spinning solid-state 1H NMR (MAS-ss-1H NMR). PSM and DOPC have the same headgroup structure, but one phospholipid was selectively observed by deuterating the trimethylammonium group of the other phospholipid. The addition of Pr3+ to the medium surrounding aLUVs selectively shifted the chemical shift of the (CH3)3N+ group in the outer leaflet from that in the inner leaflet, which allowed estimation of the inter-leaflet distribution ratio of the unlabeled lipid in aLUVs. Using this method, we evaluated the translocation of PSM and DOPC between the outer and inner leaflets of the cholesterol-containing aLUVs, with PSM and DOPC mostly distributed in the outer and inner leaflets, respectively, immediately after aLUV preparation; their flip and flop rates were approximately 2.7 and 6.4 × 10-6 s-1, respectively. During the passive symmetrization of aLUVs, the lipid translocation rate was decreased due to changes in the membrane order, probably through the formation of the registered liquid-ordered domains. Comparison of the result with that of symmetric LUVs revealed that lipid asymmetry may not significantly affect the lipid translocation rates, while the lateral lipid-lipid interaction may be a dominant factor in lipid translocation under these conditions. These findings highlight the importance of considering the effects of lateral lipid interactions within the same leaflet on lipid flip-flop rates when evaluating the asymmetry of phospholipids in the cell membrane.
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Affiliation(s)
- Hirofumi Watanabe
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
| | - Shinya Hanashima
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
- Graduate School of Engineering, Tottori University, 4-101 Koyama-cho Minami, Tottori 680-8550, Japan
| | - Yo Yano
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
| | - Tomokazu Yasuda
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, Toyonaka 560-0043, Osaka, Japan
| | - Michio Murata
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, Toyonaka 560-0043, Osaka, Japan
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Rudajev V, Novotny J. Cholesterol-dependent amyloid β production: space for multifarious interactions between amyloid precursor protein, secretases, and cholesterol. Cell Biosci 2023; 13:171. [PMID: 37705117 PMCID: PMC10500844 DOI: 10.1186/s13578-023-01127-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 09/05/2023] [Indexed: 09/15/2023] Open
Abstract
Amyloid β is considered a key player in the development and progression of Alzheimer's disease (AD). Many studies investigating the effect of statins on lowering cholesterol suggest that there may be a link between cholesterol levels and AD pathology. Since cholesterol is one of the most abundant lipid molecules, especially in brain tissue, it affects most membrane-related processes, including the formation of the most dangerous form of amyloid β, Aβ42. The entire Aβ production system, which includes the amyloid precursor protein (APP), β-secretase, and the complex of γ-secretase, is highly dependent on membrane cholesterol content. Moreover, cholesterol can affect amyloidogenesis in many ways. Cholesterol influences the stability and activity of secretases, but also dictates their partitioning into specific cellular compartments and cholesterol-enriched lipid rafts, where the amyloidogenic machinery is predominantly localized. The most complicated relationships have been found in the interaction between cholesterol and APP, where cholesterol affects not only APP localization but also the precise character of APP dimerization and APP processing by γ-secretase, which is important for the production of Aβ of different lengths. In this review, we describe the intricate web of interdependence between cellular cholesterol levels, cholesterol membrane distribution, and cholesterol-dependent production of Aβ, the major player in AD.
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Affiliation(s)
- Vladimir Rudajev
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jiri Novotny
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
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Al Badri YN, Chaw CS, Elkordy AA. Insights into Asymmetric Liposomes as a Potential Intervention for Drug Delivery Including Pulmonary Nanotherapeutics. Pharmaceutics 2023; 15:pharmaceutics15010294. [PMID: 36678922 PMCID: PMC9867527 DOI: 10.3390/pharmaceutics15010294] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/22/2022] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Liposome-based drug delivery systems are nanosized spherical lipid bilayer carriers that can encapsulate a broad range of small drug molecules (hydrophilic and hydrophobic drugs) and large drug molecules (peptides, proteins, and nucleic acids). They have unique characteristics, such as a self-assembling bilayer vesicular structure. There are several FDA-approved liposomal-based medicines for treatment of cancer, bacterial, and viral infections. Most of the FDA-approved liposomal-based therapies are in the form of conventional "symmetric" liposomes and they are administered mainly by injection. Arikace® is the first and only FDA-approved liposomal-based inhalable therapy (amikacin liposome inhalation suspension) to treat only adults with difficult-to-treat Mycobacterium avium complex (MAC) lung disease as a combinational antibacterial treatment. To date, no "asymmetric liposomes" are yet to be approved, although asymmetric liposomes have many advantages due to the asymmetric distribution of lipids through the liposome's membrane (which is similar to the biological membranes). There are many challenges for the formulation and stability of asymmetric liposomes. This review will focus on asymmetric liposomes in contrast to conventional liposomes as a potential clinical intervention drug delivery system as well as the formulation techniques available for symmetric and asymmetric liposomes. The review aims to renew the research in liposomal nanovesicle delivery systems with particular emphasis on asymmetric liposomes as future potential carriers for enhancing drug delivery including pulmonary nanotherapeutics.
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Affiliation(s)
| | | | - Amal Ali Elkordy
- Correspondence: ; Tel.: +44-(0)-1915152576; Fax: +44-(0)-1915153405
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Madsen JJ, Rossman JS. Cholesterol and M2 Rendezvous in Budding and Scission of Influenza A Virus. Subcell Biochem 2023; 106:441-459. [PMID: 38159237 DOI: 10.1007/978-3-031-40086-5_16] [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] [Indexed: 01/03/2024]
Abstract
The cholesterol of the host cell plasma membrane and viral M2 protein plays a crucial role in multiple stages of infection and replication of the influenza A virus. Cholesterol is required for the formation of heterogeneous membrane microdomains (or rafts) in the budozone of the host cell that serves as assembly sites for the viral components. The raft microstructures act as scaffolds for several proteins. Cholesterol may further contribute to the mechanical forces necessary for membrane scission in the last stage of budding and help to maintain the stability of the virus envelope. The M2 protein has been shown to cause membrane scission in model systems by promoting the formation of curved lipid bilayer structures that, in turn, can lead to membrane vesicles budding off or scission intermediates. Membrane remodeling by M2 is intimately linked with cholesterol as it affects local lipid composition, fluidity, and stability of the membrane. Thus, both cholesterol and M2 protein contribute to the efficient and proper release of newly formed influenza viruses from the virus-infected cells.
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Affiliation(s)
- Jesper J Madsen
- Global and Planetary Health, Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, FL, USA.
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Jeremy S Rossman
- School of Biosciences, University of Kent, Canterbury, Kent, UK
- Research-Aid Networks, Chicago, IL, USA
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Himbert S, Rheinstädter MC. Structural and mechanical properties of the red blood cell’s cytoplasmic membrane seen through the lens of biophysics. Front Physiol 2022; 13:953257. [PMID: 36171967 PMCID: PMC9510598 DOI: 10.3389/fphys.2022.953257] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/15/2022] [Indexed: 11/27/2022] Open
Abstract
Red blood cells (RBCs) are the most abundant cell type in the human body and critical suppliers of oxygen. The cells are characterized by a simple structure with no internal organelles. Their two-layered outer shell is composed of a cytoplasmic membrane (RBCcm) tethered to a spectrin cytoskeleton allowing the cell to be both flexible yet resistant against shear stress. These mechanical properties are intrinsically linked to the molecular composition and organization of their shell. The cytoplasmic membrane is expected to dominate the elastic behavior on small, nanometer length scales, which are most relevant for cellular processes that take place between the fibrils of the cytoskeleton. Several pathologies have been linked to structural and compositional changes within the RBCcm and the cell’s mechanical properties. We review current findings in terms of RBC lipidomics, lipid organization and elastic properties with a focus on biophysical techniques, such as X-ray and neutron scattering, and Molecular Dynamics simulations, and their biological relevance. In our current understanding, the RBCcm’s structure is patchy, with nanometer sized liquid ordered and disordered lipid, and peptide domains. At the same time, it is surprisingly soft, with bending rigidities κ of 2–4 kBT. This is in strong contrast to the current belief that a high concentration of cholesterol results in stiff membranes. This extreme softness is likely the result of an interaction between polyunsaturated lipids and cholesterol, which may also occur in other biological membranes. There is strong evidence in the literature that there is no length scale dependence of κ of whole RBCs.
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Affiliation(s)
- Sebastian Himbert
- Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada
- Origins Institute, McMaster University, Hamilton, ON, Canada
- *Correspondence: Sebastian Himbert, ; Maikel C. Rheinstädter,
| | - Maikel C. Rheinstädter
- Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada
- Origins Institute, McMaster University, Hamilton, ON, Canada
- *Correspondence: Sebastian Himbert, ; Maikel C. Rheinstädter,
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Astrocytic PTEN regulates neuropathic pain by facilitating HMGCR-dependent cholesterol biosynthesis. Pain 2022; 163:e1192-e1206. [PMID: 35559917 DOI: 10.1097/j.pain.0000000000002682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 04/01/2022] [Indexed: 11/25/2022]
Abstract
ABSTRACT Recent studies have noted the role of the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in developing neuropathic pain, but the underlying mechanisms are obscure. We found that PTEN was mainly expressed in astrocytes in the rat spinal cord and dramatically downregulated after chronic constriction injury (CCI). Intrathecal injection of a PTEN inhibitor induced pain-related behaviors in naïve rats. In contrast, administration of a PTEN protector effectively mitigated CCI-induced pain. Adeno-associated virus (AAV)-mediated overexpression of astrocytic PTEN in the spinal cord reduced glial activation and neuroinflammation and subsequently alleviated pain-related behaviors. Importantly, astrocyte-specific PTEN-knockout (Pten conditional knockout, Pten CKO) mice showed nociceptive sensitization and glial activation. Proteomic analysis revealed that PTEN overexpression upregulated at least 7 enzymes in the cholesterol biosynthesis pathway and the total cholesterol level in the spinal cord of CCI rats. Furthermore, PTEN directly interacted with enzymes, including 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), in the cholesterol biosynthesis pathway. Astrocytic HMGCR overexpression alleviated both CCI-induced pain and mechanical allodynia in Pten CKO mice. Finally, cholesterol replenishment attenuated CCI-induced pain and suppressed spinal glial activation. Taken together, these findings imply that spinal astrocytic PTEN plays a beneficial role in CCI-induced pain by regulating cholesterol biosynthesis, and increased level of PTEN may accelerate cholesterol biosynthesis and reduce glial activation, thereby alleviating neuropathic pain. Recovery of PTEN or cholesterol might be an effective therapeutic strategy for neuropathic pain.
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Perez-Salas U, Garg S, Gerelli Y, Porcar L. Deciphering lipid transfer between and within membranes with time-resolved small-angle neutron scattering. CURRENT TOPICS IN MEMBRANES 2021; 88:359-412. [PMID: 34862031 DOI: 10.1016/bs.ctm.2021.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This review focuses on time-resolved neutron scattering, particularly time-resolved small angle neutron scattering (TR-SANS), as a powerful in situ noninvasive technique to investigate intra- and intermembrane transport and distribution of lipids and sterols in lipid membranes. In contrast to using molecular analogues with potentially large chemical tags that can significantly alter transport properties, small angle neutron scattering relies on the relative amounts of the two most abundant isotope forms of hydrogen: protium and deuterium to detect complex membrane architectures and transport processes unambiguously. This review discusses advances in our understanding of the mechanisms that sustain lipid asymmetry in membranes-a key feature of the plasma membrane of cells-as well as the transport of lipids between membranes, which is an essential metabolic process.
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Affiliation(s)
- Ursula Perez-Salas
- Physics Department, University of Illinois at Chicago, Chicago, IL, United States.
| | - Sumit Garg
- Physics Department, University of Illinois at Chicago, Chicago, IL, United States
| | - Yuri Gerelli
- Department of Life and Environmental Sciences, Universita` Politecnica delle Marche, Ancona, Italy
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Liehn EA, Lupan AM, Diaconu R, Ioana M, Streata I, Manole C, Burlacu A. Heart function assessment during aging in apolipoprotein E knock-out mice. Discoveries (Craiova) 2021; 9:e136. [PMID: 34816004 PMCID: PMC8605688 DOI: 10.15190/d.2021.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Apolipoprotein (apo) E isoforms have strong correlations with metabolic and cardiovascular diseases. However, it is not clear if apoE has a role in development of non-ischemic cardiomyopathy. Our study aims to analyze the involvement of apoE in non-ischemic cardiomyopathy. METHODS AND RESULTS Serial echo-cardiographic measurements were performed in old wildtype and apoE deficient (apoE-/-) mice. Morphological and functional cardiac parameters were in normal range in both groups at the age of 12 month. At the age of 18 months, both groups had shown ventricular dilation and increased heart rates. However, the apoE-/- mice presented signs of diastolic dysfunction by hypertrophic changes in left ventricle, due probably to arterial hypertension. The right ventricle was not affected by age or genotype. CONCLUSION: Even in the absence of high fat diet, apoE deficiency in mice induces mild changes in the cardiac function of the left ventricle during aging, by developing diastolic dysfunction, which leads to heart failure with preserved ejection fraction. However, further studies are necessary to conclude over the role of apoE in cardiac physiology and its involvement in development of heart failure.
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Affiliation(s)
- Elisa A Liehn
- Human Genetic Laboratory, University of Medicine and Pharmacy of Craiova, Craiova, Romania.,Department of Cardiology, Angiology and Intensive Care, Medical Faculty, University Hospital Aachen, Aachen, Germany.,Victor Babes National Institute of Pathology, Bucharest, Romania
| | - Ana-Mihaela Lupan
- Nicolae Simionescu Institute of Cellular Biology and Pathology, Bucharest, Romania
| | - Rodica Diaconu
- Human Genetic Laboratory, University of Medicine and Pharmacy of Craiova, Craiova, Romania.,Department of Cardiology, Angiology and Intensive Care, Medical Faculty, University Hospital Aachen, Aachen, Germany
| | - Mihai Ioana
- Human Genetic Laboratory, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Ioana Streata
- Human Genetic Laboratory, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Catalin Manole
- Victor Babes National Institute of Pathology, Bucharest, Romania
| | - Alexandrina Burlacu
- Nicolae Simionescu Institute of Cellular Biology and Pathology, Bucharest, Romania
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9
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Diaconu R, Schaaps N, Afify M, Boor P, Cornelissen A, Florescu RA, Simsekyilmaz S, El-Khoury T, Schumacher D, Ioana M, Streata I, Militaru C, Donoiu I, Vogt F, Liehn EA. Apolipoprotein E4 Is Associated with Right Ventricular Dysfunction in Dilated Cardiomyopathy-An Animal and In-Human Comparative Study. Int J Mol Sci 2021; 22:ijms22189688. [PMID: 34575848 PMCID: PMC8468742 DOI: 10.3390/ijms22189688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 08/29/2021] [Accepted: 08/30/2021] [Indexed: 01/03/2023] Open
Abstract
ApoE abnormality represents a well-known risk factor for cardiovascular diseases. Beyond its role in lipid metabolism, novel studies demonstrate a complex involvement of apoE in membrane homeostasis and signaling as well as in nuclear transcription. Due to the large spread of apoE isoforms in the human population, there is a need to understand the apoE’s role in pathological processes. Our study aims to dissect the involvement of apoE in heart failure. We showed that apoE-deficient rats present multiple organ damages (kidney, liver, lung and spleen) besides the known predisposition for obesity and affected lipid metabolism (two-fold increase in tissular damages in liver and one-fold increase in kidney, lung and spleen). Heart tissue also showed significant morphological changes in apoE−/− rats, mostly after a high-fat diet. Interestingly, the right ventricle of apoE−/− rats fed a high-fat diet showed more damage and affected collagen content (~60% less total collagen content and double increase in collagen1/collagen3 ratio) compared with the left ventricle (no significant differences in total collagen content or collagen1/collagen3 ratio). In patients, we were able to find a correlation between the presence of ε4 allele and cardiomyopathy (χ2 = 10.244; p = 0.001), but also with right ventricle dysfunction with decreased TAPSE (15.3 ± 2.63 mm in ε4-allele-presenting patients vs. 19.8 ± 3.58 mm if the ε4 allele is absent, p < 0.0001*) and increased in systolic pulmonary artery pressure (50.44 ± 16.47 mmHg in ε4-allele-presenting patients vs. 40.68 ± 15.94 mmHg if the ε4 allele is absent, p = 0.0019). Our results confirm that the presence of the ε4 allele is a lipid-metabolism-independent risk factor for heart failure. Moreover, we show for the first time that the presence of the ε4 allele is associated with right ventricle dysfunction, implying different regulatory mechanisms of fibroblasts and the extracellular matrix in both ventricles. This is essential to be considered and thoroughly investigated before the design of therapeutical strategies for patients with heart failure.
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Affiliation(s)
- Rodica Diaconu
- Human Genetic Laboratory, Faculty of Medicine, University of Medicine and Pharmacy, 200349 Craiova, Romania; (R.D.); (M.I.); (I.S.)
- Department of Cardiology, University of Medicine and Pharmacy, 200349 Craiova, Romania; (C.M.); (I.D.)
| | - Nicole Schaaps
- Department of Cardiology, Angiology and Intensive Care, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (N.S.); (M.A.); (A.C.); (R.A.F.); (T.E.-K.); (F.V.)
| | - Mamdouh Afify
- Department of Cardiology, Angiology and Intensive Care, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (N.S.); (M.A.); (A.C.); (R.A.F.); (T.E.-K.); (F.V.)
- Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt
| | - Peter Boor
- Medical Faculty, Institute of Pathology, RWTH Aachen University, 52074 Aachen, Germany;
| | - Anne Cornelissen
- Department of Cardiology, Angiology and Intensive Care, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (N.S.); (M.A.); (A.C.); (R.A.F.); (T.E.-K.); (F.V.)
| | - Roberta A. Florescu
- Department of Cardiology, Angiology and Intensive Care, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (N.S.); (M.A.); (A.C.); (R.A.F.); (T.E.-K.); (F.V.)
| | - Sakine Simsekyilmaz
- Department for Pharmacology and Clinical Pharmacology, Medical Faculty, University Hospital Düsseldorf, 40225 Düsseldorf, Germany;
| | - Teddy El-Khoury
- Department of Cardiology, Angiology and Intensive Care, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (N.S.); (M.A.); (A.C.); (R.A.F.); (T.E.-K.); (F.V.)
| | - David Schumacher
- Department of Anesthesiology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany;
- Medical Faculty, Institute of Experimental Medicine and Systems Biology, RWTH Aachen University, 52074 Aachen, Germany
| | - Mihai Ioana
- Human Genetic Laboratory, Faculty of Medicine, University of Medicine and Pharmacy, 200349 Craiova, Romania; (R.D.); (M.I.); (I.S.)
| | - Ioana Streata
- Human Genetic Laboratory, Faculty of Medicine, University of Medicine and Pharmacy, 200349 Craiova, Romania; (R.D.); (M.I.); (I.S.)
| | - Constantin Militaru
- Department of Cardiology, University of Medicine and Pharmacy, 200349 Craiova, Romania; (C.M.); (I.D.)
| | - Ionut Donoiu
- Department of Cardiology, University of Medicine and Pharmacy, 200349 Craiova, Romania; (C.M.); (I.D.)
| | - Felix Vogt
- Department of Cardiology, Angiology and Intensive Care, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (N.S.); (M.A.); (A.C.); (R.A.F.); (T.E.-K.); (F.V.)
| | - Elisa A. Liehn
- Human Genetic Laboratory, Faculty of Medicine, University of Medicine and Pharmacy, 200349 Craiova, Romania; (R.D.); (M.I.); (I.S.)
- Department of Cardiology, Angiology and Intensive Care, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany; (N.S.); (M.A.); (A.C.); (R.A.F.); (T.E.-K.); (F.V.)
- Medical Faculty, Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, 52074 Aachen, Germany
- Institute for Pathology “Victor Babes”, 050096 Bucharest, Romania
- Correspondence:
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Kim DH, Triet HM, Ryu SH. Regulation of EGFR activation and signaling by lipids on the plasma membrane. Prog Lipid Res 2021; 83:101115. [PMID: 34242725 DOI: 10.1016/j.plipres.2021.101115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/02/2021] [Accepted: 07/01/2021] [Indexed: 12/12/2022]
Abstract
Lipids on the plasma membrane are not only components of the membrane biophysical structures but also regulators of receptor functions. Recently, the critical roles of lipid-protein interactions have been intensively highlighted. Epidermal growth factor receptor (EGFR) is one of the most extensively studied receptors exhibiting various lipid interactions, including interactions with phosphatidylcholine, phosphatidylserine, phosphatidylinositol phosphate, cholesterol, gangliosides, and palmitate. Here, we review recent findings on how direct interaction with these lipids regulates EGFR activation and signaling, providing unprecedented insight into the comprehensive roles of various lipids in the control of EGFR functions. Finally, the current limitations in investigating lipid-protein interactions and novel technologies to potentially overcome these limitations are discussed.
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Affiliation(s)
- Do-Hyeon Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hong Minh Triet
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sung Ho Ryu
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.
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11
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García‐Sanz P, M.F.G. Aerts J, Moratalla R. The Role of Cholesterol in α-Synuclein and Lewy Body Pathology in GBA1 Parkinson's Disease. Mov Disord 2021; 36:1070-1085. [PMID: 33219714 PMCID: PMC8247417 DOI: 10.1002/mds.28396] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023] Open
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disease where dopaminergic neurons in the substantia nigra are lost, resulting in a decrease in striatal dopamine and, consequently, motor control. Dopaminergic degeneration is associated with the appearance of Lewy bodies, which contain membrane structures and proteins, including α-synuclein (α-Syn), in surviving neurons. PD displays a multifactorial pathology and develops from interactions between multiple elements, such as age, environmental conditions, and genetics. Mutations in the GBA1 gene represent one of the major genetic risk factors for PD. This gene encodes an essential lysosomal enzyme called β-glucocerebrosidase (GCase), which is responsible for degrading the glycolipid glucocerebroside into glucose and ceramide. GCase can generate glucosylated cholesterol via transglucosylation and can also degrade the sterol glucoside. Although the molecular mechanisms that predispose an individual to neurodegeneration remain unknown, the role of cholesterol in PD pathology deserves consideration. Disturbed cellular cholesterol metabolism, as reflected by accumulation of lysosomal cholesterol in GBA1-associated PD cellular models, could contribute to changes in lipid rafts, which are necessary for synaptic localization and vesicle cycling and modulation of synaptic integrity. α-Syn has been implicated in the regulation of neuronal cholesterol, and cholesterol facilitates interactions between α-Syn oligomers. In this review, we integrate the results of previous studies and describe the cholesterol landscape in cellular homeostasis and neuronal function. We discuss its implication in α-Syn and Lewy body pathophysiological mechanisms underlying PD, focusing on the role of GCase and cholesterol. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Patricia García‐Sanz
- Instituto Cajal, CSICMadridSpain
- Centro de Investigación Biomédica en Red sobre Enfermedades NeurodegenerativasInstituto de Salud Carlos IIIMadridSpain
| | - Johannes M.F.G. Aerts
- Medical Biochemistry, Leiden Institute of Chemistry, Leiden UniversityFaculty of ScienceLeidenthe Netherlands
| | - Rosario Moratalla
- Instituto Cajal, CSICMadridSpain
- Centro de Investigación Biomédica en Red sobre Enfermedades NeurodegenerativasInstituto de Salud Carlos IIIMadridSpain
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12
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El-Beyrouthy J, Freeman E. Characterizing the Structure and Interactions of Model Lipid Membranes Using Electrophysiology. MEMBRANES 2021; 11:319. [PMID: 33925756 PMCID: PMC8145864 DOI: 10.3390/membranes11050319] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/22/2021] [Accepted: 04/25/2021] [Indexed: 11/16/2022]
Abstract
The cell membrane is a protective barrier whose configuration determines the exchange both between intracellular and extracellular regions and within the cell itself. Consequently, characterizing membrane properties and interactions is essential for advancements in topics such as limiting nanoparticle cytotoxicity. Characterization is often accomplished by recreating model membranes that approximate the structure of cellular membranes in a controlled environment, formed using self-assembly principles. The selected method for membrane creation influences the properties of the membrane assembly, including their response to electric fields used for characterizing transmembrane exchanges. When these self-assembled model membranes are combined with electrophysiology, it is possible to exploit their non-physiological mechanics to enable additional measurements of membrane interactions and phenomena. This review describes several common model membranes including liposomes, pore-spanning membranes, solid supported membranes, and emulsion-based membranes, emphasizing their varying structure due to the selected mode of production. Next, electrophysiology techniques that exploit these structures are discussed, including conductance measurements, electrowetting and electrocompression analysis, and electroimpedance spectroscopy. The focus of this review is linking each membrane assembly technique to the properties of the resulting membrane, discussing how these properties enable alternative electrophysiological approaches to measuring membrane characteristics and interactions.
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Affiliation(s)
| | - Eric Freeman
- School of Environmental, Civil, Agricultural and Mechanical Engineering, College of Engineering, University of Georgia, Athens, GA 30602, USA;
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13
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Aghaaminiha M, Farnoud AM, Sharma S. Quantitative relationship between cholesterol distribution and ordering of lipids in asymmetric lipid bilayers. SOFT MATTER 2021; 17:2742-2752. [PMID: 33533367 DOI: 10.1039/d0sm01709d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The plasma membrane of eukaryotic cells is known to be compositionally asymmetric. Certain phospholipids, such as sphingomyelin and phosphatidylcholine species, are predominantly localized in the outer leaflet, while phosphatidylethanolamine and phosphatidylserine species primarily reside in the inner leaflet. While phospholipid asymmetry between the membrane leaflets is well established, there is no consensus about cholesterol distribution between the two leaflets. We have performed a systematic study, via molecular simulations, of how the spatial distribution of cholesterol molecules in different "asymmetric" lipid bilayers are affected by the lipids' backbone, head-type, unsaturation, and chain-length by considering an asymmetric bilayer mimicking the plasma membrane lipids of red blood cells, as well as seventeen other asymmetric bilayers comprising of different lipid types. Our results reveal that the distribution of cholesterol in the leaflets is solely a function of the extent of ordering of the lipids within the leaflets. The ratio of the amount of cholesterol matches the ratio of lipid order in the two leaflets, thus providing a quantitative relationship between the two. These results are understood by the observation that asymmetric bilayers with equimolar amount of lipids in the two leaflets develop tensile and compressive stresses due to differences in the extent of lipid order. These stresses are alleviated by the transfer of cholesterol from the leaflet in compressive stress to the one in tensile stress. These findings are important in understanding the biology of the cell membrane, especially with regard to the composition of the membrane leaflets.
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Affiliation(s)
- Mohammadreza Aghaaminiha
- Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, OH 45701, USA.
| | - Amir M Farnoud
- Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, OH 45701, USA.
| | - Sumit Sharma
- Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, OH 45701, USA.
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14
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Jakubec M, Bariås E, Furse S, Govasli ML, George V, Turcu D, Iashchishyn IA, Morozova-Roche LA, Halskau Ø. Cholesterol-containing lipid nanodiscs promote an α-synuclein binding mode that accelerates oligomerization. FEBS J 2021; 288:1887-1905. [PMID: 32892498 DOI: 10.1111/febs.15551] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 07/28/2020] [Accepted: 09/01/2020] [Indexed: 01/09/2023]
Abstract
Dysregulation of the biosynthesis of cholesterol and other lipids has been implicated in many neurological diseases, including Parkinson's disease. Misfolding of α-synuclein (α-Syn), the main actor in Parkinson's disease, is associated with changes in a lipid environment. However, the exact molecular mechanisms underlying cholesterol effect on α-Syn binding to lipids as well as α-Syn oligomerization and fibrillation remain elusive, as does the relative importance of cholesterol compared to other factors. We probed the interactions and fibrillation behaviour of α-Syn using styrene-maleic acid nanodiscs, containing zwitterionic and anionic lipid model systems with and without cholesterol. Surface plasmon resonance and thioflavin T fluorescence assays were employed to monitor α-Syn binding, as well as fibrillation in the absence and presence of membrane models. 1 H-15 N-correlated NMR was used to monitor the fold of α-Syn in response to nanodisc binding, determining individual residue apparent affinities for the nanodisc-contained bilayers. The addition of cholesterol inhibited α-Syn interaction with lipid bilayers and, however, significantly promoted α-Syn fibrillation, with a more than a 20-fold reduction of lag times before fibrillation onset. When α-Syn bilayer interactions were analysed at an individual residue level by solution-state NMR, we observed two different effects of cholesterol. In nanodiscs made of DOPC, the addition of cholesterol modulated the NAC part of α-Syn, leading to stronger interaction of this region with the lipid bilayer. In contrast, in the nanodiscs comprising DOPC, DOPE and DOPG, the NAC part was mostly unaffected by the presence of cholesterol, while the binding of the N and the C termini was both inhibited.
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Affiliation(s)
- Martin Jakubec
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Espen Bariås
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Samuel Furse
- Department of Molecular Biology, University of Bergen, Norway
| | - Morten L Govasli
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
- Division of Infection and Immunity, University College London, London, UK
| | - Vinnit George
- Department of Chemistry, University of Bergen, Norway
| | - Diana Turcu
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
| | - Igor A Iashchishyn
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | | | - Øyvind Halskau
- Department of Biological Sciences, University of Bergen, Norway
- Department of Molecular Biology, University of Bergen, Norway
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15
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Pathan-Chhatbar S, Drechsler C, Richter K, Morath A, Wu W, OuYang B, Xu C, Schamel WW. Direct Regulation of the T Cell Antigen Receptor's Activity by Cholesterol. Front Cell Dev Biol 2021; 8:615996. [PMID: 33490080 PMCID: PMC7820176 DOI: 10.3389/fcell.2020.615996] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 12/09/2020] [Indexed: 11/14/2022] Open
Abstract
Biological membranes consist of hundreds of different lipids that together with the embedded transmembrane (TM) proteins organize themselves into small nanodomains. In addition to this function of lipids, TM regions of proteins bind to lipids in a very specific manner, but the function of these TM region-lipid interactions is mostly unknown. In this review, we focus on the role of plasma membrane cholesterol, which directly binds to the αβ T cell antigen receptor (TCR), and has at least two opposing functions in αβ TCR activation. On the one hand, cholesterol binding to the TM domain of the TCRβ subunit keeps the TCR in an inactive, non-signaling conformation by stabilizing this conformation. This assures that the αβ T cell remains quiescent in the absence of antigenic peptide-MHC (the TCR's ligand) and decreases the sensitivity of the T cell toward stimulation. On the other hand, cholesterol binding to TCRβ leads to an increased formation of TCR nanoclusters, increasing the avidity of the TCRs toward the antigen, thus increasing the sensitivity of the αβ T cell. In mouse models, pharmacological increase of the cholesterol concentration in T cells caused an increase in TCR clustering, and thereby enhanced anti-tumor responses. In contrast, the γδ TCR does not bind to cholesterol and might be regulated in a different manner. The goal of this review is to put these seemingly controversial findings on the impact of cholesterol on the αβ TCR into perspective.
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Affiliation(s)
- Salma Pathan-Chhatbar
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Carina Drechsler
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Kirsten Richter
- Immunology, Infectious Diseases and Ophthalmology Disease Translational Area, Roche Innovation Center Basel, Basel, Switzerland
| | - Anna Morath
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Wei Wu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Bo OuYang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Chenqi Xu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wolfgang W. Schamel
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
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16
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Luchini A, Vitiello G. Mimicking the Mammalian Plasma Membrane: An Overview of Lipid Membrane Models for Biophysical Studies. Biomimetics (Basel) 2020; 6:biomimetics6010003. [PMID: 33396534 PMCID: PMC7838988 DOI: 10.3390/biomimetics6010003] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 12/23/2020] [Accepted: 12/28/2020] [Indexed: 02/07/2023] Open
Abstract
Cell membranes are very complex biological systems including a large variety of lipids and proteins. Therefore, they are difficult to extract and directly investigate with biophysical methods. For many decades, the characterization of simpler biomimetic lipid membranes, which contain only a few lipid species, provided important physico-chemical information on the most abundant lipid species in cell membranes. These studies described physical and chemical properties that are most likely similar to those of real cell membranes. Indeed, biomimetic lipid membranes can be easily prepared in the lab and are compatible with multiple biophysical techniques. Lipid phase transitions, the bilayer structure, the impact of cholesterol on the structure and dynamics of lipid bilayers, and the selective recognition of target lipids by proteins, peptides, and drugs are all examples of the detailed information about cell membranes obtained by the investigation of biomimetic lipid membranes. This review focuses specifically on the advances that were achieved during the last decade in the field of biomimetic lipid membranes mimicking the mammalian plasma membrane. In particular, we provide a description of the most common types of lipid membrane models used for biophysical characterization, i.e., lipid membranes in solution and on surfaces, as well as recent examples of their applications for the investigation of protein-lipid and drug-lipid interactions. Altogether, promising directions for future developments of biomimetic lipid membranes are the further implementation of natural lipid mixtures for the development of more biologically relevant lipid membranes, as well as the development of sample preparation protocols that enable the incorporation of membrane proteins in the biomimetic lipid membranes.
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Affiliation(s)
- Alessandra Luchini
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark;
| | - Giuseppe Vitiello
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
- CSGI-Center for Colloid and Surface Science, via della Lastruccia 3, 50019 Sesto Fiorentino (Florence), Italy
- Correspondence:
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17
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Fibrillization of 40-Residue β-Amyloid Peptides in Membrane-Like Environments Leads to Different Fibril Structures and Reduced Molecular Polymorphisms. Biomolecules 2020; 10:biom10060881. [PMID: 32521743 PMCID: PMC7356566 DOI: 10.3390/biom10060881] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/28/2020] [Accepted: 06/04/2020] [Indexed: 12/31/2022] Open
Abstract
The molecular-level polymorphism in β-Amyloid (Aβ) fibrils have recently been considered as a pathologically relevant factor in Alzheimer’s disease (AD). Studies showed that the structural deviations in human-brain-seeded Aβ fibrils potentially correlated with the clinical histories of AD patients. For the 40-residue Aβ (Aβ40) fibrils derived from human brain tissues, a predominant molecular structure was proposed based on solid-state nuclear magnetic resonance (ssNMR) spectroscopy. However, previous studies have shown that the molecular structures of Aβ40 fibrils were sensitive to their growth conditions in aqueous environments. We show in this work that biological membranes and their phospholipid bilayer mimics serve as environmental factors to reduce the structural heterogeneity in Aβ40 fibrils. Fibrillization in the presence of membranes leads to fibril structures that are significantly different to the Aβ40 fibrils grown in aqueous solutions. Fibrils grown from multiple types of membranes, including the biological membranes extracted from the rats’ synaptosomes, shared similar ssNMR spectral features. Our studies emphasize the biological relevance of membranes in Aβ40 fibril structures and fibrillization processes.
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18
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Wang J, Li W, Zhou F, Feng R, Wang F, Zhang S, Li J, Li Q, Wang Y, Xie J, Wen T. ATP11B deficiency leads to impairment of hippocampal synaptic plasticity. J Mol Cell Biol 2019; 11:688-702. [PMID: 31152587 PMCID: PMC7261485 DOI: 10.1093/jmcb/mjz042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/28/2019] [Accepted: 03/15/2019] [Indexed: 12/13/2022] Open
Abstract
Synaptic plasticity is known to regulate and support signal transduction between neurons, while synaptic dysfunction contributes to multiple neurological and other brain disorders; however, the specific mechanism underlying this process remains unclear. In the present study, abnormal neural and dendritic morphology was observed in the hippocampus following knockout of Atp11b both in vitro and in vivo. Moreover, ATP11B modified synaptic ultrastructure and promoted spine remodeling via the asymmetrical distribution of phosphatidylserine and enhancement of glutamate release, glutamate receptor expression, and intracellular Ca2+ concentration. Furthermore, experimental results also indicate that ATP11B regulated synaptic plasticity in hippocampal neurons through the MAPK14 signaling pathway. In conclusion, our data shed light on the possible mechanisms underlying the regulation of synaptic plasticity and lay the foundation for the exploration of proteins involved in signal transduction during this process.
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Affiliation(s)
- Jiao Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Weihao Li
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Fangfang Zhou
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Ruili Feng
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Fushuai Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Shibo Zhang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Jie Li
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Qian Li
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Yajiang Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Jiang Xie
- School of Computer Engineering and Science, Shanghai University, Shanghai, China
| | - Tieqiao Wen
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
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19
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DelBove CE, Strothman CE, Lazarenko RM, Huang H, Sanders CR, Zhang Q. Reciprocal modulation between amyloid precursor protein and synaptic membrane cholesterol revealed by live cell imaging. Neurobiol Dis 2019; 127:449-461. [PMID: 30885793 PMCID: PMC6588454 DOI: 10.1016/j.nbd.2019.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 02/03/2019] [Accepted: 03/12/2019] [Indexed: 12/20/2022] Open
Abstract
The amyloid precursor protein (APP) has been extensively studied because of its association with Alzheimer's disease (AD). However, APP distribution across different subcellular membrane compartments and its function in neurons remains unclear. We generated an APP fusion protein with a pH-sensitive green fluorescent protein at its ectodomain and a pH-insensitive blue fluorescent protein at its cytosolic domain and used it to measure APP's distribution, subcellular trafficking, and cleavage in live neurons. This reporter, closely resembling endogenous APP, revealed only a limited correlation between synaptic activities and APP trafficking. However, the synaptic surface fraction of APP was increased by a reduction in membrane cholesterol levels, a phenomenon that involves APP's cholesterol-binding motif. Mutations at or near binding sites not only reduced both the surface fraction of APP and membrane cholesterol levels in a dominant negative manner, but also increased synaptic vulnerability to moderate membrane cholesterol reduction. Our results reveal reciprocal modulation of APP and membrane cholesterol levels at synaptic boutons.
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Affiliation(s)
- Claire E DelBove
- Department of Pharmacology, Vanderbilt University, United States of America
| | - Claire E Strothman
- Department of Cell and Developmental Biology, Vanderbilt University, United States of America
| | - Roman M Lazarenko
- Department of Pharmacology, Vanderbilt University, United States of America
| | - Hui Huang
- Department of Biochemistry, Vanderbilt University, United States of America
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, United States of America; Department of Medicine, Vanderbilt University Medical Center, United States of America
| | - Qi Zhang
- Department of Pharmacology, Vanderbilt University, United States of America; Brain Institute, Florida Atlantic University, United States of America.
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20
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Rivel T, Ramseyer C, Yesylevskyy S. The asymmetry of plasma membranes and their cholesterol content influence the uptake of cisplatin. Sci Rep 2019; 9:5627. [PMID: 30948733 PMCID: PMC6449338 DOI: 10.1038/s41598-019-41903-w] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/18/2019] [Indexed: 12/20/2022] Open
Abstract
The composition of the plasma membrane of malignant cells is thought to influence the cellular uptake of cisplatin and to take part in developing resistance to this widespread anti-cancer drug. In this work we study the permeation of cisplatin through the model membranes of normal and cancer cells using molecular dynamics simulations. A special attention is paid to lipid asymmetry and cholesterol content of the membranes. The loss of lipid asymmetry, which is common for cancer cells, leads to a decrease in their permeability to cisplatin by one order of magnitude in comparison to the membranes of normal cells. The change in the cholesterol molar ratio from 0% to 33% also decreases the permeability of the membrane by approximately one order of magnitude. The permeability of pure DOPC membrane is 5-6 orders of magnitude higher than one of the membranes with realistic lipid composition, which makes it as an inadequate model for the studies of drug permeability.
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Affiliation(s)
- Timothée Rivel
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France.
| | - Christophe Ramseyer
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
| | - Semen Yesylevskyy
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France.,Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, 03028, Kyiv, Ukraine
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21
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Liehn EA, Ponomariov V, Diaconu R, Streata I, Ioana M, Crespo-Avilan GE, Hernández-Reséndiz S, Cabrera-Fuentes HA. Apolipoprotein E in Cardiovascular Diseases: Novel Aspects of an Old-fashioned Enigma. Arch Med Res 2018; 49:522-529. [PMID: 30213474 DOI: 10.1016/j.arcmed.2018.08.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 08/24/2018] [Indexed: 12/30/2022]
Abstract
The presence of different APOE isoforms represents a well-known risk factor for cardiovascular diseases. Besides the pleiotropic effects of APOE polymorphism on heart and neurological diseases, this review summarizes the less-known functions of APOE and the possible implications for cardiovascular disorders. Beyond the role as lipid transporting protein, its involvement in lipid membrane homeostasis and signaling, as well as its nuclear transcriptional effects suggests a more complex role of APOE, receiving great interest from researchers and physicians from all medical fields. Due to the presence of different APOE isoforms in human population, understanding APOE's role in pathological processes represents not only a challenge, but a demand for further development of therapeutic strategies for cardiovascular diseases.
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Affiliation(s)
- Elisa A Liehn
- Institute for Molecular Cardiovascular Research, Rheinisch Westfälische Technische Hochschule Aachen University, Aachen, Germany; Human Genomics Laboratory, University of Medicine and Pharmacy Craiova, Craiova, Romania; Department of Cardiology, Pulmonology, Angiology and Intensive Care, University Hospital, Rheinisch Westfälische Technische Hochschule, Aachen, Germany
| | - Victor Ponomariov
- Institute for Molecular Cardiovascular Research, Rheinisch Westfälische Technische Hochschule Aachen University, Aachen, Germany; Human Genomics Laboratory, University of Medicine and Pharmacy Craiova, Craiova, Romania
| | - Rodica Diaconu
- Human Genomics Laboratory, University of Medicine and Pharmacy Craiova, Craiova, Romania
| | - Ioana Streata
- Human Genomics Laboratory, University of Medicine and Pharmacy Craiova, Craiova, Romania
| | - Mihai Ioana
- Human Genomics Laboratory, University of Medicine and Pharmacy Craiova, Craiova, Romania
| | - Gustavo E Crespo-Avilan
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore; National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore
| | - Sauri Hernández-Reséndiz
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore; National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore
| | - Hector A Cabrera-Fuentes
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore, Singapore; National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore; Kazan Federal University, Department of Microbiology, Kazan, Russian Federation; Escuela de Ingenieria y Ciencias, Centro de Biotecnologia-FEMSA, Tecnologico de Monterrey, Nuevo Leon, México; Institute of Biochemistry, Medical School, Justus-Liebig-University, Giessen, Germany.
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22
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Steck TL, Lange Y. Transverse distribution of plasma membrane bilayer cholesterol: Picking sides. Traffic 2018; 19:750-760. [PMID: 29896788 DOI: 10.1111/tra.12586] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 12/23/2022]
Abstract
The transverse asymmetry (sidedness) of phospholipids in plasma membrane bilayers is well characterized, distinctive, actively maintained and functionally important. In contrast, numerous studies using a variety of techniques have concluded that plasma membrane bilayer cholesterol is either mostly in the outer leaflet or the inner leaflet or is fairly evenly distributed. Sterols might simply partition according to their differing affinities for the asymmetrically disposed phospholipids, but some studies have proposed that it is actively transported to the outer leaflet. Other work suggests that the sterol is enriched in the inner leaflet, driven by either positive interactions with the phosphatidylethanolamine on that side or by its exclusion from the outer leaflet by the long chain sphingomyelin molecules therein. This uncertainty raises three questions: is plasma membrane cholesterol sidedness fixed in a given cell or cell type; is it generally the same among mammalian species; and does it serve specific physiological functions? This review grapples with these issues.
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Affiliation(s)
- Theodore L Steck
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois
| | - Yvonne Lange
- Department of Pathology, Rush University Medical Center, Chicago, Illinois
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23
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Niu Z, Zhang Z, Zhao W, Yang J. Interactions between amyloid β peptide and lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1663-1669. [PMID: 29679539 DOI: 10.1016/j.bbamem.2018.04.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/12/2018] [Accepted: 04/12/2018] [Indexed: 10/17/2022]
Abstract
The presence of amyloid plaques in the brain is a typical characteristic of Alzheimer's disease (AD). Amyloid plaques are formed from the deposits of aggregated amyloid β peptide (Aβ). The toxicity induced by Aβ aggregates is correlated with Aβ-membrane interactions. The mutual influences between aggregation and membranes are complicated and unclear. In recent years advanced experiments and findings are emerging to give us more detailed information on Aβ-membrane interactions. In this review, we mainly focus on the Aβ-membrane interactions and membrane-induced Aβ structures. The mechanism of Aβ-membrane interactions is also summarized, which provides insights into the prevention and treatment of AD.
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Affiliation(s)
- Zheng Niu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, 430071 Wuhan, PR China
| | - Zhengfeng Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, 430071 Wuhan, PR China
| | - Weijing Zhao
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, 430071 Wuhan, PR China
| | - Jun Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, 430071 Wuhan, PR China.
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24
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Preferential selection of Arginine at the lipid-water-interface of TRPV1 during vertebrate evolution correlates with its snorkeling behaviour and cholesterol interaction. Sci Rep 2017; 7:16808. [PMID: 29196683 PMCID: PMC5711878 DOI: 10.1038/s41598-017-16780-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 11/11/2017] [Indexed: 02/07/2023] Open
Abstract
TRPV1 is a thermo-sensitive ion channel involved in neurosensory and other physiological functions. The trans-membrane helices of TRPV1 undergo quick and complex conformational changes governed by thermodynamic parameters and membrane components leading to channel opening. However, the molecular mechanisms underlying such events are poorly understood. Here we analysed the molecular evolution of TRPV1 at the lipid-water-interface region (LWI), typically defined as a layer of 6 Å thickness on each side of the membrane with less availability of free water. Amino acids demarcating the end of the trans-membrane helices are highly conserved. Residues present in the inner leaflet are more conserved and have been preferentially selected over others. Amino acids with snorkeling properties (Arginine and Tyrosine) undergo specific selection during the vertebrate evolution in a cholesterol-dependent and/or body temperature manner. Results suggest that H-bond formation between the OH- group of cholesterol and side chain of Arg557 or Arg575 at the inner leaflet is a critical parameter that can regulate channel functions. Different LWI mutants of TRPV1 have altered membrane localization and deficient colocalization with lipid raft markers. These findings may help to understand the lipid-protein interactions, and molecular basis of different neuronal functions. Such findings may have broad importance in the context of differential sensory responses, pathophysiologies, and application of pharmacological drugs such as anaesthetics acting on TRPVs.
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Brown AM, Bevan DR. Molecular Dynamics Simulations of Amyloid β-Peptide (1-42): Tetramer Formation and Membrane Interactions. Biophys J 2017; 111:937-49. [PMID: 27602722 DOI: 10.1016/j.bpj.2016.08.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/29/2016] [Accepted: 08/02/2016] [Indexed: 01/10/2023] Open
Abstract
The aggregation cascade and peptide-membrane interactions of the amyloid β-peptide (Aβ) have been implicated as toxic events in the development and progression of Alzheimer's disease. Aβ42 forms oligomers and ultimately plaques, and it has been hypothesized that these oligomeric species are the main toxic species contributing to neuronal cell death. To better understand oligomerization events and subsequent oligomer-membrane interactions of Aβ42, we performed atomistic molecular-dynamics (MD) simulations to characterize both interpeptide interactions and perturbation of model membranes by the peptides. MD simulations were utilized to first show the formation of a tetramer unit by four separate Aβ42 peptides. Aβ42 tetramers adopted an oblate ellipsoid shape and showed a significant increase in β-strand formation in the final tetramer unit relative to the monomers, indicative of on-pathway events for fibril formation. The Aβ42 tetramer unit that formed in the initial simulations was used in subsequent MD simulations in the presence of a pure POPC or cholesterol-rich raft model membrane. Tetramer-membrane simulations resulted in elongation of the tetramer in the presence of both model membranes, with tetramer-raft interactions giving rise to the rearrangement of key hydrophobic regions in the tetramer and the formation of a more rod-like structure indicative of a fibril-seeding aggregate. Membrane perturbation by the tetramer was manifested in the form of more ordered, rigid membranes, with the pure POPC being affected to a greater extent than the raft membrane. These results provide critical atomistic insight into the aggregation pathway of Aβ42 and a putative toxic mechanism in the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Anne M Brown
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia
| | - David R Bevan
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia.
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26
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Marquardt D, Kučerka N, Wassall SR, Harroun TA, Katsaras J. Cholesterol's location in lipid bilayers. Chem Phys Lipids 2016; 199:17-25. [DOI: 10.1016/j.chemphyslip.2016.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/01/2016] [Accepted: 04/02/2016] [Indexed: 02/07/2023]
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Egawa J, Pearn ML, Lemkuil BP, Patel PM, Head BP. Membrane lipid rafts and neurobiology: age-related changes in membrane lipids and loss of neuronal function. J Physiol 2016; 594:4565-79. [PMID: 26332795 PMCID: PMC4983616 DOI: 10.1113/jp270590] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 08/13/2015] [Indexed: 12/15/2022] Open
Abstract
A better understanding of the cellular physiological role that plasma membrane lipids, fatty acids and sterols play in various cellular systems may yield more insight into how cellular and whole organ function is altered during the ageing process. Membrane lipid rafts (MLRs) within the plasma membrane of most cells serve as key organizers of intracellular signalling and tethering points of cytoskeletal components. MLRs are plasmalemmal microdomains enriched in sphingolipids, cholesterol and scaffolding proteins; they serve as a platform for signal transduction, cytoskeletal organization and vesicular trafficking. Within MLRs are the scaffolding and cholesterol binding proteins named caveolin (Cav). Cavs not only organize a multitude of receptors including neurotransmitter receptors (NMDA and AMPA receptors), signalling proteins that regulate the production of cAMP (G protein-coupled receptors, adenylyl cyclases, phosphodiesterases (PDEs)), and receptor tyrosine kinases involved in growth (Trk), but also interact with components that modulate actin and tubulin cytoskeletal dynamics (e.g. RhoGTPases and actin binding proteins). MLRs are essential for the regulation of the physiology of organs such as the brain, and age-related loss of cholesterol from the plasma membrane leads to loss of MLRs, decreased presynaptic vesicle fusion, and changes in neurotransmitter release, all of which contribute to different forms of neurodegeneration. Thus, MLRs provide an active membrane domain that tethers and reorganizes the cytoskeletal machinery necessary for membrane and cellular repair, and genetic interventions that restore MLRs to normal cellular levels may be exploited as potential therapeutic means to reverse the ageing and neurodegenerative processes.
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Affiliation(s)
- Junji Egawa
- Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA
- Department of Anesthesiology, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Matthew L Pearn
- Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA
- Department of Anesthesiology, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Brian P Lemkuil
- Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA
- Department of Anesthesiology, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Piyush M Patel
- Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA
- Department of Anesthesiology, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Brian P Head
- Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA
- Department of Anesthesiology, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
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Pannuzzo M. On the physiological/pathological link between Aβ peptide, cholesterol, calcium ions and membrane deformation: A molecular dynamics study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1380-9. [DOI: 10.1016/j.bbamem.2016.03.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/23/2016] [Accepted: 03/17/2016] [Indexed: 01/12/2023]
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Sharma S, Kim BN, Stansfeld PJ, Sansom MSP, Lindau M. A Coarse Grained Model for a Lipid Membrane with Physiological Composition and Leaflet Asymmetry. PLoS One 2015; 10:e0144814. [PMID: 26659855 PMCID: PMC4681583 DOI: 10.1371/journal.pone.0144814] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 11/24/2015] [Indexed: 11/24/2022] Open
Abstract
The resemblance of lipid membrane models to physiological membranes determines how well molecular dynamics (MD) simulations imitate the dynamic behavior of cell membranes and membrane proteins. Physiological lipid membranes are composed of multiple types of phospholipids, and the leaflet compositions are generally asymmetric. Here we describe an approach for self-assembly of a Coarse-Grained (CG) membrane model with physiological composition and leaflet asymmetry using the MARTINI force field. An initial set-up of two boxes with different types of lipids according to the leaflet asymmetry of mammalian cell membranes stacked with 0.5 nm overlap, reliably resulted in the self-assembly of bilayer membranes with leaflet asymmetry resembling that of physiological mammalian cell membranes. Self-assembly in the presence of a fragment of the plasma membrane protein syntaxin 1A led to spontaneous specific positioning of phosphatidylionositol(4,5)bisphosphate at a positively charged stretch of syntaxin consistent with experimental data. An analogous approach choosing an initial set-up with two concentric shells filled with different lipid types results in successful assembly of a spherical vesicle with asymmetric leaflet composition. Self-assembly of the vesicle in the presence of the synaptic vesicle protein synaptobrevin 2 revealed the correct position of the synaptobrevin transmembrane domain. This is the first CG MD method to form a membrane with physiological lipid composition as well as leaflet asymmetry by self-assembly and will enable unbiased studies of the incorporation and dynamics of membrane proteins in more realistic CG membrane models.
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Affiliation(s)
- Satyan Sharma
- Laboratory for Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
- * E-mail:
| | - Brian N. Kim
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, United States of America
| | - Phillip J. Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, England, United Kingdom
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, England, United Kingdom
| | - Manfred Lindau
- Laboratory for Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, United States of America
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30
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Milianta PJ, Muzzio M, Denver J, Cawley G, Lee S. Water Permeability across Symmetric and Asymmetric Droplet Interface Bilayers: Interaction of Cholesterol Sulfate with DPhPC. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:12187-12196. [PMID: 26492572 DOI: 10.1021/acs.langmuir.5b02748] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cellular membranes employ a variety of strategies for controlling the flow of small molecules into the cytoplasmic space, including incorporation of sterols for modulation of permeability and maintenance of lipid asymmetry to provide both sides of the membrane with differing biophysical properties. The specific case of cholesterol asymmetry, especially, is known to have profound effects in neurological cellular systems. Synthetic membrane models that can readily determine valuable physical parameters, such as water transport rates, for sterol-containing membranes of defined lipid composition remain in demand. We report the use of the droplet interface bilayer (DIB), composed of adherent aqueous droplets surrounded by a lipid monolayer and immersed in a hydrophobic medium, for measurement of water permeability across the membrane, with rapid visualization and ease of experimental setup. We studied droplet bilayer membranes composed of the prototypical synthetic membrane lipid (i.e., the archaeal lipid DPhPC) as well as of symmetric and asymmetric DIBs formed by DPhPC and sodium cholesterol sulfate (S-Chol). The presence of S-Chol in DPhPC in symmetric DIB reduced the passive water permeability rate (P(f)) at all concentrations and increased the activation energy (E(a)) to 17-18 kcal/mol. When only one side of the DIB contains S-Chol (asymmetric DIB), an E(a) of 14-15 kcal/mol was obtained, a value intermediate that of pure lipid and symmetrical DIB containing lipid and S-Chol. Our data are consistent with a capability for regulation of water transport by one leaflet independent of the other. The engineering of our various systems is believed to have implications for garnering detailed knowledge regarding the transport of small moieties across bilayers in a wide variety of lipid systems.
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Affiliation(s)
- Peter J Milianta
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Michelle Muzzio
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Jacqueline Denver
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Geoffrey Cawley
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Sunghee Lee
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
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31
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Nickels JD, Smith JC, Cheng X. Lateral organization, bilayer asymmetry, and inter-leaflet coupling of biological membranes. Chem Phys Lipids 2015; 192:87-99. [DOI: 10.1016/j.chemphyslip.2015.07.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/20/2015] [Accepted: 07/25/2015] [Indexed: 11/28/2022]
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32
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Marquardt D, Geier B, Pabst G. Asymmetric lipid membranes: towards more realistic model systems. MEMBRANES 2015; 5:180-96. [PMID: 25955841 PMCID: PMC4496639 DOI: 10.3390/membranes5020180] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 04/28/2015] [Indexed: 01/23/2023]
Abstract
Despite the ubiquity of transbilayer asymmetry in natural cell membranes, the vast majority of existing research has utilized chemically well-defined symmetric liposomes, where the inner and outer bilayer leaflets have the same composition. Here, we review various aspects of asymmetry in nature and in model systems in anticipation for the next phase of model membrane studies.
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Affiliation(s)
- Drew Marquardt
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
| | - Barbara Geier
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
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33
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Visco I, Chiantia S, Schwille P. Asymmetric supported lipid bilayer formation via methyl-β-cyclodextrin mediated lipid exchange: influence of asymmetry on lipid dynamics and phase behavior. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:7475-84. [PMID: 24885372 DOI: 10.1021/la500468r] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Supported lipid bilayers (SLBs) are broadly used as minimal membrane models and commonly produced by vesicle fusion (VF) on solid supports. Despite its advantages, VF does not allow the controlled formation of bilayers that mimic the leaflet asymmetry in lipid composition normally found in biological systems. Here we present a simple, quick, and versatile method to produce SLBs with a desired asymmetric lipid composition which is stable for ca. 4 h. We apply methyl-β-cyclodextrin mediated lipid exchange to SLBs formed by VF to enrich the upper leaflet of the bilayer with sphingomyelin. The bilayer asymmetry is assessed by fluorescence correlation spectroscopy, measuring the lipid mobility separately in each leaflet. To check the compatibility of the method with the most common protein reconstitution approaches, we report the production of asymmetric SLBs (aSLBs) in the presence of a glycosylphosphatidylinositol-anchored protein, reconstituted in the bilayer both, via direct protein insertion, and via proteoliposomes fusion. We finally apply aSLBs to study phase separation and transbilayer lipid movement of raft-mimicking lipid mixtures. The observed differences in terms of phase separation in symmetric and asymmetric SLBs with the same overall lipid composition provide further experimental evidence that the transversal lipid distribution affects the overall lipid miscibility and allow to temporally investigate leaflet mixing.
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Affiliation(s)
- Ilaria Visco
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany
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34
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Yandrapalli N, Muriaux D, Favard C. Lipid domains in HIV-1 assembly. Front Microbiol 2014; 5:220. [PMID: 24904536 PMCID: PMC4033000 DOI: 10.3389/fmicb.2014.00220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 04/26/2014] [Indexed: 12/14/2022] Open
Abstract
In CD+4 T cells, HIV-1 buds from the host cell plasma membrane. The viral Gag polyprotein is mainly responsible for this process. However, the intimate interaction of Gag and lipids at the plasma membrane as well as its consequences, in terms of lipids lateral organization and virus assembly, is still under debate. In this review we propose to revisit the role of plasma membrane lipids in HIV-1 Gag targeting and assembly, at the light of lipid membranes biophysics and literature dealing with Gag-lipid interactions.
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Affiliation(s)
- Naresh Yandrapalli
- Centre d'étude des Pathogènes et de Biotechnologies pour la Santé, CNRS UMR-5236 Montpellier Cedex, France
| | - Delphine Muriaux
- Centre d'étude des Pathogènes et de Biotechnologies pour la Santé, CNRS UMR-5236 Montpellier Cedex, France
| | - Cyril Favard
- Centre d'étude des Pathogènes et de Biotechnologies pour la Santé, CNRS UMR-5236 Montpellier Cedex, France
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35
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Wood WG, Li L, Müller WE, Eckert GP. Cholesterol as a causative factor in Alzheimer's disease: a debatable hypothesis. J Neurochem 2014; 129:559-72. [PMID: 24329875 PMCID: PMC3999290 DOI: 10.1111/jnc.12637] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 11/24/2013] [Accepted: 12/09/2013] [Indexed: 12/17/2022]
Abstract
High serum/plasma cholesterol levels have been suggested as a risk factor for Alzheimer's disease (AD). Some reports, mostly retrospective epidemiological studies, have observed a decreased prevalence of AD in patients taking the cholesterol lowering drugs, statins. The strongest evidence causally linking cholesterol to AD is provided by experimental studies showing that adding/reducing cholesterol alters amyloid precursor protein (APP) and amyloid beta-protein (Ab) levels. However, there are problems with the cholesterol-AD hypothesis. Cholesterol levels in serum/plasma and brain of AD patients do not support cholesterol as a causative factor in AD.Prospective studies on statins and AD have largely failed to show efficacy. Even the experimental data are open to interpretation given that it is well-established that modification of cholesterol levels has effects on multiple proteins, not only amyloid precursor protein and Ab. The purpose of this review, therefore, was to examine the above-mentioned issues, discuss the pros and cons of the cholesterol-AD hypothesis, involvement of other lipids in the mevalonate pathway, and consider that AD may impact cholesterol homeostasis.
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Affiliation(s)
- W. Gibson Wood
- Geriatric Research, Education and Clinical Center, VAMC, Department of Pharmacology, University of Minnesota School of Medicine, Minneapolis, MN 55455 USA
| | - Ling Li
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455 USA
| | - Walter E. Müller
- Department of Pharmacology, Biocenter Niederursel, Goethe University, Max-von-Laue-St. 9, 60438 Frankfurt, Germany
| | - Gunter P. Eckert
- Department of Pharmacology, Biocenter Niederursel, Goethe University, Max-von-Laue-St. 9, 60438 Frankfurt, Germany
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36
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Rice LM, Donigan M, Yang M, Liu W, Pandya D, Joseph BK, Sodi V, Gearhart TL, Yip J, Bouchard M, Nickels JT. Protein phosphatase 2A (PP2A) regulates low density lipoprotein uptake through regulating sterol response element-binding protein-2 (SREBP-2) DNA binding. J Biol Chem 2014; 289:17268-79. [PMID: 24770487 DOI: 10.1074/jbc.m114.570390] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
LDL-cholesterol (LDL-C) uptake by Ldlr is regulated at the transcriptional level by the cleavage-dependent activation of membrane-associated sterol response element-binding protein (SREBP-2). Activated SREBP-2 translocates to the nucleus, where it binds to an LDLR promoter sterol response element (SRE), increasing LDLR gene expression and LDL-C uptake. SREBP-2 cleavage and translocation steps are well established. Several SREBP-2 phosphorylation sites have been mapped and functionally characterized. The phosphatases dephosphorylating these sites remain elusive. The phosphatase(s) regulating SREBP-2 represents a novel pharmacological target for treating hypercholesterolemia. Here we show that protein phosphatase 2A (PP2A) promotes SREBP-2 LDLR promoter binding in response to cholesterol depletion. No binding to an LDLR SRE was observed in the presence of the HMG-CoA reductase inhibitor, lovastatin, when PP2A activity was inhibited by okadaic acid or depleted by siRNA methods. SREBP-2 cleavage and nuclear translocation were not affected by loss of PP2A. PP2A activity was required for SREBP-2 DNA binding. In response to cholesterol depletion, PP2A directly interacted with SREBP-2 and altered its phosphorylation state, causing an increase in SREBP-2 binding to an LDLR SRE site. Increased binding resulted in induced LDLR gene expression and increased LDL uptake. We conclude that PP2A activity regulates cholesterol homeostasis and LDL-C uptake.
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Affiliation(s)
| | - Melissa Donigan
- the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691 and
| | - Muhua Yang
- the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691 and
| | - Weidong Liu
- the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691 and
| | - Devanshi Pandya
- the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691 and
| | - Biny K Joseph
- the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691 and
| | | | - Tricia L Gearhart
- the Department of Molecular Biology and Biochemistry, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Jenny Yip
- the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691 and
| | - Michael Bouchard
- the Department of Molecular Biology and Biochemistry, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Joseph T Nickels
- the Institute of Metabolic Disorders, Genesis Biotechnology Group, Hamilton, New Jersey 08691 and
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37
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Eckmann J, Clemens LE, Eckert SH, Hagl S, Yu-Taeger L, Bordet T, Pruss RM, Muller WE, Leuner K, Nguyen HP, Eckert GP. Mitochondrial membrane fluidity is consistently increased in different models of Huntington disease: restorative effects of olesoxime. Mol Neurobiol 2014; 50:107-18. [PMID: 24633813 DOI: 10.1007/s12035-014-8663-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/18/2014] [Indexed: 12/12/2022]
Abstract
Huntington disease (HD) is a fatal neurodegenerative disorder caused by a CAG repeat expansion in exon 1 of the huntingtin gene (HTT). One prominent target of the mutant huntingtin protein (mhtt) is the mitochondrion, affecting its morphology, distribution, and function. Thus, mitochondria have been suggested as potential therapeutic targets for the treatment of HD. Olesoxime, a cholesterol-like compound, promotes motor neuron survival and neurite outgrowth in vitro, and its effects are presumed to occur via a direct interaction with mitochondrial membranes (MMs). We examined the properties of MMs isolated from cell and animal models of HD as well as the effects of olesoxime on MM fluidity and cholesterol levels. MMs isolated from brains of aged Hdh Q111/Q111 knock-in mice showed a significant decrease in 1,6-diphenyl-hexatriene (DPH) anisotropy, which is inversely correlated with membrane fluidity. Similar increases in MM fluidity were observed in striatal STHdh Q111/Q111 cells as well as in MMs isolated from brains of BACHD transgenic rats. Treatment of STHdh cells with olesoxime decreased the fluidity of isolated MMs. Decreased membrane fluidity was also measured in olesoxime-treated MMs isolated from brains of HD knock-in mice. In both models, treatment with olesoxime restored HD-specific changes in MMs. Accordingly, olesoxime significantly counteracted the mhtt-induced increase in MM fluidity of MMs isolated from brains of BACHD rats after 12 months of treatment in vivo, possibly by enhancing MM cholesterol levels. Thus, olesoxime may represent a novel pharmacological tool to treat mitochondrial dysfunction in HD.
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Affiliation(s)
- Janett Eckmann
- Department of Pharmacology, Biocenter, Goethe-University Campus Riedberg, Biocentre Geb. N260, R.1.09, Max-von-Laue Str. 9, 60438, Frankfurt, Germany
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38
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Sonnino S, Aureli M, Grassi S, Mauri L, Prioni S, Prinetti A. Lipid Rafts in Neurodegeneration and Neuroprotection. Mol Neurobiol 2013; 50:130-48. [DOI: 10.1007/s12035-013-8614-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/08/2013] [Indexed: 11/28/2022]
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39
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Song Y, Kenworthy AK, Sanders CR. Cholesterol as a co-solvent and a ligand for membrane proteins. Protein Sci 2013; 23:1-22. [PMID: 24155031 DOI: 10.1002/pro.2385] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 09/27/2013] [Accepted: 10/01/2013] [Indexed: 01/23/2023]
Abstract
As of mid 2013 a Medline search on "cholesterol" yielded over 200,000 hits, reflecting the prominence of this lipid in numerous aspects of animal cell biology and physiology under conditions of health and disease. Aberrations in cholesterol homeostasis underlie both a number of rare genetic disorders and contribute to common sporadic and complex disorders including heart disease, stroke, type II diabetes, and Alzheimer's disease. The corresponding author of this review and his lab stumbled only recently into the sprawling area of cholesterol research when they discovered that the amyloid precursor protein (APP) binds cholesterol, a topic covered by the Hans Neurath Award lecture at the 2013 Protein Society Meeting. Here, we first provide a brief overview of cholesterol-protein interactions and then offer our perspective on how and why binding of cholesterol to APP and its C99 domain (β-CTF) promotes the amyloidogenic pathway, which is closely related to the etiology of Alzheimer's disease.
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Affiliation(s)
- Yuanli Song
- Department of Biochemistry, Center for Structural Biology and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, 37232
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40
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Raina V, Gupta S, Yadav S, Surolia A. Simvastatin induced neurite outgrowth unveils role of cell surface cholesterol and acetyl CoA carboxylase in SH-SY5Y cells. PLoS One 2013; 8:e74547. [PMID: 24040277 PMCID: PMC3770597 DOI: 10.1371/journal.pone.0074547] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/02/2013] [Indexed: 01/08/2023] Open
Abstract
Statins are known to modulate cell surface cholesterol (CSC) and AMP-activated protein kinase (AMPK) in non-neural cells; however no study demonstrates whether CSC and AMPK may regulate simvastatin induced neuritogenesis (SIN). We found that simvastatin (SIM) maintains CSC as shown by Fillipin III staining, Flotillin-2 protein expression / localization and phosphorylation of various receptor tyrosine kinases (RTKs) in the plasma membrane. Modulation of CSC revealed that SIN is critically dependent on this CSC. Simultaneously, phospho array for mitogen activated protein kinases (MAPKs) revealed PI3K / Akt as intracellular pathway which modulates lipid pathway by inhibiting AMPK activation. Though, SIM led to a transient increase in AMPK phosphorylation followed by a sudden decline; the effect was independent of PI3K. Strikingly, AMPK phosphorylation was regulated by protein phosphatase 2A (PP2A) activity which was enhanced upon SIM treatment as evidenced by increase in threonine phosphorylation. Moreover, it was observed that addition of AMP analogue and PP2A inhibitor inhibited SIN. Bio-composition of neurites shows that lipids form a major part of neurites and AMPK is known to regulate lipid metabolism majorly through acetyl CoA carboxylase (ACC). AMPK activity is negative regulator of ACC activity and we found that phosphorylation of ACC started to decrease after 6 hrs which becomes more pronounced at 12 hrs. Addition of ACC inhibitor showed that SIN is dependent on ACC activity. Simultaneously, addition of Fatty acid synthase (FAS) inhibitor confirmed that endogenous lipid pathway is important for SIN. We further investigated SREBP-1 pathway activation which controls ACC and FAS at transcriptional level. However, SIM did not affect SREBP-1 processing and transcription of its target genes likes ACC1 and FAS. In conclusion, this study highlights a distinct role of CSC and ACC in SIN which might have implication in process of neuronal differentiation induced by other agents.
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Affiliation(s)
- Varshiesh Raina
- Molecular Sciences Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, Delhi, India
| | - Sarika Gupta
- Molecular Sciences Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, Delhi, India
- * E-mail: (AS); (SG)
| | - Saurabh Yadav
- Molecular Sciences Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, Delhi, India
| | - Avadhesha Surolia
- Molecular Biophysics Unit, Indian Institute of Science, Bangaluru, Karnataka, India
- * E-mail: (AS); (SG)
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41
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Liguori N, Nerenberg P, Head-Gordon T. Embedding Aβ42 in heterogeneous membranes depends on cholesterol asymmetries. Biophys J 2013; 105:899-910. [PMID: 23972842 PMCID: PMC3752101 DOI: 10.1016/j.bpj.2013.06.046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 05/20/2013] [Accepted: 06/07/2013] [Indexed: 12/11/2022] Open
Abstract
Using a coarse-grained lipid and peptide model, we show that the free energy stabilization of amyloid-β in heterogeneous lipid membranes is predicted to have a dependence on asymmetric distributions of cholesterol compositions across the membrane leaflets. We find that a highly asymmetric cholesterol distribution that is depleted on the exofacial leaflet but enhanced on the cytofacial leaflet of the model lipid membrane thermodynamically favors membrane retention of a fully embedded Aβ peptide. However, in the case of cholesterol redistribution that increases concentration of cholesterol on the exofacial layer, typical of aging or Alzheimer's disease, the free energy favors peptide extrusion of the highly reactive N-terminus into the extracellular space that may be vulnerable to aggregation, oligomerization, or deleterious oxidative reactivity.
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Affiliation(s)
| | - Paul S. Nerenberg
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California
| | - Teresa Head-Gordon
- Department of Chemistry, University of California, Berkeley, California
- Department of Bioengineering, University of California, Berkeley, California
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California
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42
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Zito G, Polimanti R, Panetta V, Ventriglia M, Salustri C, Siotto MC, Moffa F, Altamura C, Vernieri F, Lupoi D, Cassetta E, Rossini PM, Squitti R. Antioxidant status and APOE genotype as susceptibility factors for neurodegeneration in Alzheimer's disease and vascular dementia. Rejuvenation Res 2013; 16:51-6. [PMID: 23216585 DOI: 10.1089/rej.2012.1383] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Different factors interact to develop neurodegeneration in patients with dementia and other neurodegenerative disorders. Oxidative stress and the ε4 allele of apolipoprotein E (ApoE) are associated with significant alteration in lipid metabolism, in turn connected to a variety of neurodegenerative diseases and aging. Thus, a better understanding of the pathogenetic pathways associated with lipid dyshomeostasis may elucidate the causes of neurodegenerative processes. To address this issue, we evaluated the effects of antioxidant status and APOE genotype on neurodegeneration in patients with dementia of the Alzheimer type (AD), with vascular dementia (VaD), and in elderly healthy controls. Eighty-two AD, 42 VaD patients, and 26 healthy controls were recruited and underwent medial temporal lobe atrophy (MTA) assessment, white matter hyperintensities rating (WMH), serum total antioxidant status assaying (TAS), and APOE genotyping. A logistic regression algorithm applied to our data revealed that a 0.01 mmol/L decrease of TAS concentration increased the probability of MTA by 24% (p=0.038) and that carriers of the APOE ε4 allele showed higher WMH scores (p=0.018), confirming that small variations in antioxidant systems homeostasis are associated with relevant modifications of disease risk. Furthermore, in individuals with analogous TAS values, the presence of the ε4 allele increased the predicted probability of having MTA. These outcomes further sustain the interaction of oxidative stress and APOE genotype to neurodegeneration.
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Affiliation(s)
- Giancarlo Zito
- Casa di Cura San Raffale Cassino & IRCCS San Raffale Pisana, Cassino, Italy.
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43
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Rondelli V, Del Favero E, Motta S, Cantù L, Fragneto G, Brocca P. Neutrons for rafts, rafts for neutrons. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:73. [PMID: 23852579 DOI: 10.1140/epje/i2013-13073-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 03/08/2013] [Accepted: 03/11/2013] [Indexed: 06/02/2023]
Abstract
The determination of the structure of membrane rafts is a challenging issue in biology. The selection of membrane components both in the longitudinal and transverse directions plays a major role as it determines the creation of stable or tunable platforms that host interactions with components of the outer environment. We focus here on the possibility to apply neutron scattering to the study of raft mimics. With this aim, we realized two extreme experimental models for the same complex membrane system (phospholipid : cholesterol : ganglioside GM1), involving two of the characteristic components of glycolipid-enriched rafts. One consists of a thick stack of tightly packed membranes, mixed and symmetric in composition, deposited on a silicon wafer and analyzed by neutron diffraction. The other consists of a free floating individual membrane, mixed and asymmetric in composition in the two layers, studied by neutron reflection. We present here results on the ganglioside-cholesterol coupling. Ganglioside GM1 is found to force the redistribution of cholesterol between the two layers of the model membranes. This causes cholesterol exclusion from compositionally symmetric ganglioside-containing membranes, or, alternatively, asymmetric cholesterol enrichment in raft-mimics, where gangliosides reside into the opposite layer.
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Affiliation(s)
- V Rondelli
- Department of Medical Biotechnologies and Traslational Medicine, University of Milan, Segrate, Italy
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44
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Santos AJM, Meinecke M, Fessler MB, Holden DW, Boucrot E. Preferential invasion of mitotic cells by Salmonella reveals that cell surface cholesterol is maximal during metaphase. J Cell Sci 2013; 126:2990-6. [PMID: 23687374 DOI: 10.1242/jcs.115253] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cell surface-exposed cholesterol is crucial for cell attachment and invasion of many viruses and bacteria, including the bacterium Salmonella, which causes typhoid fever and gastroenteritis. Using flow cytometry and 3D confocal fluorescence microscopy, we found that mitotic cells, although representing only 1-4% of an exponentially growing population, were much more efficiently targeted for invasion by Salmonella. This targeting was not dependent on the spherical shape of mitotic cells, but was instead SipB and cholesterol dependent. Thus, we measured the levels of plasma membrane and cell surface cholesterol throughout the cell cycle using, respectively, brief staining with filipin and a fluorescent ester of polyethylene glycol-cholesterol that cannot flip through the plasma membrane, and found that both were maximal during mitosis. This increase was due not only to the rise in global cell cholesterol levels along the cell cycle but also to a transient loss in cholesterol asymmetry at the plasma membrane during mitosis. We measured that cholesterol, but not phosphatidylserine, changed from a ∼2080 outerinner leaflet repartition during interphase to ∼5050 during metaphase, suggesting this was specific to cholesterol and not due to a broad change of lipid asymmetry during metaphase. This explains the increase in outer surface levels that make dividing cells more susceptible to Salmonella invasion and perhaps to other viruses and bacteria entering cells in a cholesterol-dependent manner. The change in cholesterol partitioning also favoured the recruitment of activated ERM (Ezrin, Radixin, Moesin) proteins at the plasma membrane and thus supported mitotic cell rounding.
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Affiliation(s)
- António J M Santos
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
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45
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Ganglioside GM1 forces the redistribution of cholesterol in a biomimetic membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2860-7. [DOI: 10.1016/j.bbamem.2012.07.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 07/05/2012] [Accepted: 07/17/2012] [Indexed: 11/22/2022]
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46
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Jiang L, Bechtel MD, Galeva NA, Williams TD, Michaelis EK, Michaelis ML. Decreases in plasma membrane Ca²⁺-ATPase in brain synaptic membrane rafts from aged rats. J Neurochem 2012; 123:689-99. [PMID: 22889001 DOI: 10.1111/j.1471-4159.2012.07918.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/31/2012] [Accepted: 08/07/2012] [Indexed: 12/18/2022]
Abstract
Precise regulation of free intracellular Ca(2+) concentrations [Ca(2+) ](i) is critical for normal neuronal function, and alterations in Ca(2+) homeostasis are associated with brain aging and neurodegenerative diseases. One of the most important proteins controlling [Ca(2+) ](i) is the plasma membrane Ca(2+) -ATPase (PMCA), the high-affinity transporter that fine tunes the cytosolic nanomolar levels of Ca(2+) . We previously found that PMCA protein in synaptic plasma membranes (SPMs) is decreased with advancing age and the decrease in enzyme activity is much greater than that in protein levels. In this study, we isolated raft and non-raft fractions from rat brain SPMs and used quantitative mass spectrometry to show that the specialized lipid microdomains in SPMs, the rafts, contain 60% of total PMCA, comprised all four isoforms. The raft PMCA pool had the highest specific activity and this decreased progressively with age. The reduction in PMCA protein could not account for the dramatic activity loss. Addition of excess calmodulin to the assay did not restore PMCA activity to that in young brains. Analysis of the major raft lipids revealed a slight age-related increase in cholesterol levels and such increases might enhance membrane lipid order and prevent further loss of PMCA activity.
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Affiliation(s)
- Lei Jiang
- Department of Pharmacology and Toxicology and Higuchi Biosciences Center, The University of Kansas, Lawrence, KS, USA
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47
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Zhao H, Zhao X, Cao X, Wu G. Age-Dependent Neuroimmune Modulation of IGF-1R in the Traumatic Mice. IMMUNITY & AGEING 2012; 9:12. [PMID: 22640633 PMCID: PMC3416715 DOI: 10.1186/1742-4933-9-12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 05/28/2012] [Indexed: 12/25/2022]
Abstract
Background Age-dependent neuroimmune modulation following traumatic stress is accompanied by discordant upregulation of Fyn signaling in the frontal cortex, but the mechanistic details of the potential cellular behavior regarding IGF-1R/Fyn have not been established. Methods Trans-synaptic IGF-1R signaling during the traumatic stress was comparably examined in wild type, Fyn (−/−) and MOR (−/−) mice. Techniques included primary neuron culture, in vitro kinase activity, immunoprecipitation, Western Blot, sucrose discontinuous centrifugation. Besides that, [3 H] incorporation was used to assay lymphocyte proliferation and NK cell activity. Results We demonstrate robust upregulation of synaptic Fyn activity following traumatic stress, with higher amplitude in 2-month mice than that in 1-year counterpart. We also established that the increased Fyn signaling is accompanied by its molecular connection with IGF-1R within the synaptic zone. Detained analysis using Fyn (−/−) and MOR (−/−) mice reveal that IGF-1R/Fyn signaling is governed to a large extent by mu opioid receptor (MOR), and with age-dependent manner; these signaling cascades played a central role in the modulation of lymphocyte proliferation and NK cell activity. Conclusions Our data argued for a pivotal role of synaptic IGF-1R/Fyn signaling controlled by MOR downstream signaling cascades were crucial for the age-dependent neuroimmune modulation following traumatic stress. The result here might present a new quality of synaptic cellular communication governing the stress like events and have significant potential for the development of therapeutic approaches designed to minimize the heightened vulnerability during aging.
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Affiliation(s)
- Hui Zhao
- Department of Integrative Medicine and Neurobiology, National Key lab of Medical Neurobiology, Institute of Brain Research Sciences, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
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48
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Stepanyants N, Jeffries GDM, Orwar O, Jesorka A. Radial sizing of lipid nanotubes using membrane displacement analysis. NANO LETTERS 2012; 12:1372-1378. [PMID: 22313341 PMCID: PMC3303199 DOI: 10.1021/nl203983e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/30/2012] [Indexed: 05/31/2023]
Abstract
We report a novel method for the measurement of lipid nanotube radii. Membrane translocation is monitored between two nanotube-connected vesicles, during the expansion of a receiving vesicle, by observing a photobleached region of the nanotube. We elucidate nanotube radii, extracted from SPE vesicles, enabling quantification of membrane composition and lamellarity. Variances of nanotube radii were measured, showing a growth of 40-56 nm, upon increasing cholesterol content from 0 to 20%.
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Affiliation(s)
| | | | | | - Aldo Jesorka
- Tel +46 31-772 6112; fax +46 31-772 2750; e-mail
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49
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Apolipoprotein E level and cholesterol are associated with reduced synaptic amyloid beta in Alzheimer's disease and apoE TR mouse cortex. Acta Neuropathol 2012; 123:39-52. [PMID: 22020632 DOI: 10.1007/s00401-011-0892-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 10/12/2011] [Accepted: 10/13/2011] [Indexed: 12/31/2022]
Abstract
The apolipoprotein E4 allele (APOE4) contributes to Alzheimer's disease (AD) risk and APOE2 is protective, but the relevant cellular mechanisms are unknown. We have used flow cytometry analysis to measure apolipoprotein E (apoE) and amyloid beta peptide (Aβ) levels in large populations of synaptic terminals from AD and aged cognitively normal controls, and demonstrate that modest but significant increases in soluble apoE levels accompany elevated Aβ in AD cortical synapses and in an APP/PS1 rat model of AD. Dual labeling experiments document co-localization of apoE and Aβ in individual synapses with concentration of Aβ in a small population of apoE-positive synapses in both AD and controls. Consistent with a clearance role, the apoE level was higher in Aβ-positive synapses in control cases. In aged targeted replacement mice expressing human apoE, apoE2/4 synaptic terminals demonstrated the highest level of apoE and the lowest level of Aβ compared to apoE3/3 and apoE4/4 lines. In apoE2/4 terminals, the pattern of immunolabeling for apoE and Aβ closely resembled the pattern in human control cases, and elevated apoE was accompanied by elevated free cholesterol in apoE2/4 synaptic terminals. These results are consistent with a role for APOE in Aβ clearance in AD synapses, and suggest that optimal lipidation of apoE2 compared to E3 and E4 makes an important contribution to Aβ clearance and synaptic function.
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50
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Gangliosides and the multiscale modulation of membrane structure. Chem Phys Lipids 2011; 164:796-810. [DOI: 10.1016/j.chemphyslip.2011.09.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/12/2011] [Accepted: 09/13/2011] [Indexed: 02/07/2023]
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