Molecular insight into neurodegeneration – Langmuir monolayer study on the influence of oxysterols on model myelin sheath. Issue 202 (September 2020)

• Record Type: Journal Article
• Authors: Chachaj-Brekiesz, Anna; Wnętrzak, Anita; Włodarska, Sara; Lipiec, Ewelina; Dynarowicz-Latka, Patrycja
• Is Part Of: Journal of steroid biochemistry and molecular biology. Issue 202(2020)
• Publication Date: 2020-09
• Subjects: AFM atomic force microscope -- BAM Brewster angle microscope -- chol cholesterol -- LB Langmuir–Blodgett -- MBP myelin basic protein -- PLP Folch–Lees proteolipid protein -- RMS Rot Mean Square -- 25−OH 25–hydroxycholesterol -- 7α−OH 7α–hydroxycholesterol -- 7β−OH 7β–hydroxycholesterol -- 7–K 7–ketocholesterol; Oxysterols -- Membrane models -- Myelin -- Demyelination -- Langmuir films; Steroid hormones -- Periodicals; Biochemistry -- Periodicals; Hormones -- Periodicals; Molecular Biology -- Periodicals; Hormones stéroïdes -- Périodiques; Steroid hormones; Periodicals; 572.579
• DOI: 10.1016/j.jsbmb.2020.105727
• Languages: English
• ISSNs: 0960-0760

Abstract

Highlights: Influence of oxysterols on myelin mimicked by Langmuir film was examined. Model myelin loses homogeneous structure in the oxysterols presence at 30–35 mN/m. Oxysterols influence fluidity of myelin model by altering the lipid organization. Oxysterols modified thermodynamic interactions and electrical properties of model. Effect of chain–oxidized sterols on myelin model integrity is more pronounced. Abstract: Systematic studies on the influence of selected ring–oxidized (7α–hydroxycholesterol, 7α−OH; 7β–hydroxycholesterol, 7β−OH; 7–ketocholesterol, 7–K) and chain–oxidized (25−OH) sterols on lipid layer of myelin were performed. Myelin sheath was modeled as five–component Langmuir monolayer (Chol:PE:SM:PS:PC 50:20:12:9:9). Particular oxysterols have been incorporated into the model myelin sheath by replacing cholesterol totally or partially (1:1). The effect of oxysterol incorporation was characterized with surface pressure and electric surface potential – area isotherms and visualized with Brewster angle microscopy (BAM) and atomic force microscopy (AFM). It has been noticed that model myelin loses its homogeneous structure (due to the appearance of domains) at physiological bilayer conditions (30–35 mN/m). In the presence of oxysterols, the fluidity of myelin model increases and the organization of lipids is altered, which is reflected in the decrease of electric surface potential changes (ΔV). The strongest myelin/oxysterol interactions have been observed for 7–K and 25−OH, being the most cytotoxic oxysterols found in biological tests.