Lipoprotein complex of equine lysozyme with oleic acid (ELOA) interactions with the plasma membrane of live cells.
Abstract: Recent evidence supports the idea that early aggregates, protein, and lipoprotein oligomers but not large aggregates like fibrils that are formed at late stages of the aggregation process are responsible for cytotoxicity. Oligomers can interact with the cellular plasma membrane affecting its structure and/or dynamics or may be taken up by the cells. In either case, disparate cascades of molecular interactions are activated in the attempt to counteract the disturbance induced by the oligomers. If unsuccessful, cell death follows. Here, we study the molecular and cellular mechanisms underlying PC12 cell death caused by ELOA oligomers. ELOA, a lipoprotein complex formed by equine lysozyme (EL) and oleic acid (OA), induces cell death in all tested cell lines, but the actual mechanism of its action is not known. We have used methods with single-molecule sensitivity, fluorescence correlation spectroscopy (FCS), fluorescence cross-correlation spectroscopy (FCCS), and confocal laser scanning microscopy (CLSM) imaging by avalanche photodiodes (APD), so-called APD imaging, to study ELOA interactions with the plasma membrane in live PC12 cells. We detected ELOA accumulation in the cell surroundings, observed ELOA interactions with the plasma membrane, and local changes in plasma membrane lipid dynamics in the vicinity of ELOA complexes. These interactions resulted in plasma membrane rupture, followed by rapid influx and distribution of ELOA inside the already dead cell. In order to probe the ELOA-plasma membrane interaction sites at the molecular and atomic levels, the ELOA complexes were further studied by photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy, nuclear magnetic resonance (NMR) and atomic force microscopy (AFM). We observed a novel mechanism of oligomer toxicity-cell death induced by continuous disturbance of the plasma membrane, eventually causing permanent plasma membrane damage and identified the sites in ELOA that are potentially involved in the interactions with the plasma membrane.
Publication Date: 2010-08-26 PubMed ID: 20735022DOI: 10.1021/la1026416Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research article investigates the interactions of a lipoprotein complex (ELOA) with the plasma membrane of live cells, and the subsequent cellular death it causes. The researchers aim to identify the molecular and cellular mechanisms driving this biological process.
Background and Purpose of the Study
- The investigators’ focus was on a complex of equine lysozyme (EL) and oleic acid (OA), known as ELOA. Previous studies suggested that early stage aggregates, like ELOA oligomers, could be cytotoxic, causing cell death by disrupting the cell membrane or by being absorbed.
- While the impact of ELOA and similar complexes on cell mortality has been recognized across various cell types, the specific mechanism leading to cell death is not well understood.
- The purpose of this study was to explore these mechanisms in greater detail, using various microscopy and spectroscopy techniques to examine ELOA’s impact on the membranes of living PC12 cells (a cell line derived from a pheochromocytoma of the rat adrenal medulla).
Methods Used in the Research
- Several high-sensitivity methods were applied, including fluorescence correlation spectroscopy (FCS), fluorescence cross-correlation spectroscopy (FCCS), and confocal laser scanning microscopy (CLSM). These techniques allowed the team to track ELOA’s interactions with and effect on the plasma membrane.
- The complex’s impacts on the cellular level were observed through avalanche photodiodes (APD) imaging.
- Additionally, photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy, nuclear magnetic resonance (NMR) and atomic force microscopy (AFM) were used to further investigate the ELOA-plasma membrane interaction sites at the molecular and atomic levels.
Main Findings of the Study
- The researchers found that ELOA aggregates interfered with the dynamics of the plasma membrane lipids, ultimately causing damage and rupture of the membrane. This chain of events facilitated the influx and distribution of ELOA inside the cell, which was already in a state of cell death.
- Significantly, the study surfaced a previously unknown method of oligomer toxicity, in which continuous disturbance of the cell plasma membrane led to permanent damage and cell death.
- The team also identified specific points on the ELOA complexes that appeared to play a role in the interaction with the cell membrane, potentially paving the way for future research or therapeutic strategies to mitigate such cytotoxic interactions.
Cite This Article
APA
Vukojević V, Bowen AM, Wilhelm K, Ming Y, Ce Z, Schleucher J, Hore PJ, Terenius L, Morozova-Roche LA.
(2010).
Lipoprotein complex of equine lysozyme with oleic acid (ELOA) interactions with the plasma membrane of live cells.
Langmuir, 26(18), 14782-14787.
https://doi.org/10.1021/la1026416 Publication
Researcher Affiliations
- Department of Clinical Neuroscience, Karolinska Institutet, 17176 Stockholm, Sweden. vladana.vukojevic@ki.se
MeSH Terms
- Animals
- Binding Sites
- Cell Membrane / metabolism
- Cell Survival
- Color
- Fluorescent Dyes / metabolism
- Horses
- Lipoproteins / metabolism
- Muramidase / metabolism
- Oleic Acid / metabolism
- PC12 Cells
- Protein Binding
- Rats
- Spectrometry, Fluorescence
Grant Funding
- Biotechnology and Biological Sciences Research Council
Citations
This article has been cited 5 times.- El-Fakharany EM, Redwan EM. Protein-lipid complexes: molecular structure, current scenarios and mechanisms of cytotoxicity. RSC Adv 2019 Nov 11;9(63):36890-36906.
- Elizarova A, Sokolov A, Kostevich V, Kisseleva E, Zelenskiy E, Zakharova E, Panasenko O, Budevich A, Semak I, Egorov V, Pontarollo G, De Filippis V, Vasilyev V. Interaction of Lactoferrin with Unsaturated Fatty Acids: In Vitro and In Vivo Study of Human Lactoferrin/Oleic Acid Complex Cytotoxicity. Materials (Basel) 2021 Mar 25;14(7).
- Rath EM, Cheng YY, Pinese M, Sarun KH, Hudson AL, Weir C, Wang YD, Håkansson AP, Howell VM, Liu GJ, Reid G, Knott RB, Duff AP, Church WB. BAMLET kills chemotherapy-resistant mesothelioma cells, holding oleic acid in an activated cytotoxic state. PLoS One 2018;13(8):e0203003.
- Kataev A, Zherelova O, Grishchenko V. A Characeae Cells Plasma Membrane as a Model for Selection of Bioactive Compounds and Drugs: Interaction of HAMLET-Like Complexes with Ion Channels of Chara corallina Cells Plasmalemma. J Membr Biol 2016 Dec;249(6):801-811.
- Ho JC, Storm P, Rydström A, Bowen B, Alsin F, Sullivan L, Ambite I, Mok KH, Northen T, Svanborg C. Lipids as tumoricidal components of human α-lactalbumin made lethal to tumor cells (HAMLET): unique and shared effects on signaling and death. J Biol Chem 2013 Jun 14;288(24):17460-71.
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