1. OxLDL alterations in endothelial cell membrane dynamics leads to changes in vesicle trafficking and increases cell susceptibility to injury.
- Author
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Couto NF, Rezende L, Fernandes-Braga W, Alves AP, Agero U, Alvarez-Leite J, Damasceno NRT, Castro-Gomes T, and Andrade LO
- Subjects
- Actins metabolism, Cell Membrane physiology, Cell Movement, Cells, Cultured, Cholesterol metabolism, Cytoskeleton metabolism, Endocytosis physiology, Endothelial Cells metabolism, Endothelium, Vascular metabolism, Exocytosis physiology, Human Umbilical Vein Endothelial Cells, Humans, Lipoproteins, LDL physiology, Lysosomes metabolism, Membranes metabolism, Protein Transport, Cell Membrane metabolism, Lipoproteins, LDL metabolism
- Abstract
Plasma membrane repair (PMR) is an important process for cell homeostasis, especially for cells under constant physical stress. Repair involves a sequence of Ca
2+ -dependent events, including lysosomal exocytosis and subsequent compensatory endocytosis. Cholesterol sequestration from plasma membrane causes actin cytoskeleton reorganization and polymerization, increasing cell stiffness, which leads to exocytosis and reduction of a peripheral pool of lysosomes involved in PMR. These changes in mechanical properties are similar to those observed in cells exposed to oxidized Low Density Lipoprotein (oxLDL), a key molecule during atherosclerosis development. Using a human umbilical vein endothelial cell line (EAhY926) we evaluated the influence of mechanical modulation induced by oxLDL in PMR and its effect in endothelial fragility. Similar to MβCD (a drug capable of sequestering cholesterol) treatment, oxLDL exposure led to actin reorganization and de novo polymerization, as well as an increase in cell rigidity and lysosomal exocytosis. Additionally, for both MβCD and oxLDL treated cells, there was an initial increase in endocytic events, likely triggered by the peak of exocytosis induced by both treatments. However, no further endocytic events were observed, suggesting that constitutive endocytosis is blocked upon treatment and that the reorganized cytoskeleton function as a mechanical barrier to membrane traffic. Finally, the increase in cell rigidity renders cells more prone to mechanical injury. Together, these data show that mechanical modulation induced by oxLDL exposure not only alters membrane traffic in cells, but also makes them more susceptible to mechanical injury, which may likely contribute to the initial steps of atherosclerosis development., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2020
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