Myelin Composition Influence on Bilayer Interactions in Multiple Sclerosis

髓磷脂成分对多发性硬化症双层相互作用的影响

• 批准号: 7297478
• 负责人: JACOB N ISRAELACHVILI
• 金额: $ 27.34万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7297478
• 关键词: Adhesions; Adhesives; Animal Model; Animals; Atomic Force Microscopy; Axon; Behavior; Brain; Callithrix; Cell membrane; Cerebrosides; Chemicals; Cholesterol; Classification; Complement component C1s; Condition; Couples; Data; Defect; Demyelinations; Disease Outcome; Electrostatics; Encephalomyelitis; Environment; Experimental Autoimmune Encephalomyelitis; Figs - dietary; Fluorescence; Fluorescence Microscopy; Goals; Healed; Image; Intervention; Lateral; Lead; Lecithin; Lipids; Liquid substance; Mechanics; Membrane; Membrane Lipids; Microscopy; Modeling; Multiple Sclerosis; Myelin; Myelin Basic Proteins; Myelin Proteins; Myelin Sheath; Nerve; Optics; Osmotic Pressure; Pharmaceutical Preparations; Phase; Phosphatidylserines; Poloxamer; Poloxamer 188; Poloxamers; Polyethylene Glycols; Polymers; Prevention; Protein Isoforms; Proteins; Range; Recombinants; Research Personnel; Rodent; Role; Side; Solutions; Sphingomyelins; Spinal cord injury; Structure; Surface; Swelling; Time; Variant; Water; Work; X ray diffraction analysis; X-Ray Diffraction; behavior influence; design; extracellular; healing; insight; interest; intracellular protein transport; monolayer; nanoscale; neurotransmission; novel; protein function; protein localization location; repaired; seal; tool; van der Waals force

DESCRIPTION (provided by applicant): Previous work has shown that potentially important changes in the lipid composition of brain myelin occur during experimental allergic encephalomyelitis (EAE), an established animal model of Multiple Sclerosis. The organization (structure) of normal and EAE lipids are different for both the cytoplasmic and extracellular monolayers. These differences in 'phase behavior' contribute to the differences in the interaction forces between myelin membranes that we have observed using the Surface Forces Apparatus (SFA), which appear to be related to the delamination of the myelin sheath. We hypothesize that the interactions between the cytoplasmic sides of the membranes are due primarily to myelin basic protein (MBP) that couples to the lipid composition, with the anionic lipid and protein isoform content being especially important. The interactions between the extracellular sides of the membrane are due exclusively to the lipids as there are no known adhesive proteins on this side. The adhesion between the extracellular surfaces is therefore likely due to non-specific interactions such as electrostatic and van der Waals forces, which should also be strongly influenced by alterations in the phase behavior and distribution of the lipids in EAE membranes. The SFA will be used to study the complete force vs distance curves of normal and EAE myelin to relate the composition and phase behavior variations to the interaction forces that hold the extracellular and cytoplasmic sides of the myelin sheath together. In addition to variations in lipid composition, the effects of different MBP isoforms (C1, C3, C8) on the membrane adhesion will be determined with the SFA to show how these isoforms couple to the lipid distribution. We will use Langmuir isotherms and fluorescence microscopy of model cytoplasmic and extracellular monolayers and bilayers to determine the relationship between lipid composition and lateral phase separation. We are especially interested in cholesterol, the anionic lipids phosphatdylserine and sphingomyelin, and the neutral lipid phosphatidylcholine, which show the greatest differences between control and EAE myelin. Atomic force microscopy (AFM) will be used in parallel to study the distribution of lipids and MBP and its isoforms at the nanometer scale. We hypothesize that polyethylene glycol (PEG) and poloxamers, non-toxic and FDA-approved polymers, recently used to treat spinal cord injuries in animals, might act to heal the myelin sheath via adding an attractive osmotic 'depletion' force to provide a similar effect that we have recently observed for MBP. This work will provide insights into the role of membrane-composition and organization on the interactions that lead to MS, as well as basic advances in understanding the relationships between lipid phase behavior, protein localization and function, and membrane demyelination.

描述（由申请人提供）：先前的工作表明，在实验性过敏性脑脊髓炎（EAE）期间，脑髓素脂质组成的潜在重要变化是多发性硬化症的既定动物模型。细胞质和细胞外单层的正常脂质和EAE脂质的组织（结构）不同。 “相行为”上的这些差异有助于使用表面力设备（SFA）观察到的髓磷脂膜之间的相互作用差异，这似乎与髓鞘的分层有关。我们假设膜的细胞质侧之间的相互作用主要归因于髓磷脂碱性蛋白（MBP）与脂质组成偶联，而阴离子脂质和蛋白质同型含量尤为重要。膜的细胞外侧之间的相互作用仅归因于脂质，因为这侧没有已知的粘合剂蛋白。因此，细胞外表面之间的粘附可能是由于非特异性相互作用（例如静电和范德华力）引起的，这也应受到EAE膜中脂质的相行为和脂质分布的变化的强烈影响。 SFA将用于研究正常和EAE髓磷脂的完整力与距离曲线，以将组成和相行为变化与固定髓鞘外鞘的细胞外和细胞质侧的相互作用力相关联。除了脂质组成的变化外，还将使用SFA确定不同MBP同工型（C1，C3，C8）对膜粘附的影响，以表明这些同工型如何与脂质分布。我们将使用模型细胞质和细胞外单层和双层的Langmuir等温线和荧光显微镜来确定脂质组成与侧相分离之间的关系。我们特别对胆固醇，阴离子脂质磷脂糖和鞘磷脂以及中性脂质磷脂酰胆碱感兴趣，这些脂质磷脂酰胆碱显示出对照和EAE髓磷脂之间最大的差异。原子力显微镜（AFM）将同时使用纳米尺度研究脂质和MBP及其同工型的分布。我们假设聚乙烯乙二醇（PEG）和戈洛沙姆，无毒和FDA批准的聚合物，最近用来治疗动物中的脊髓损伤，可能会通过增加有吸引力的渗透渗透性的“消耗”力来治愈髓磷脂鞘，以提供我们最近对MBP的类似效果，以提供类似的效果。这项工作将为膜组成和组织在导致MS的相互作用方面的作用以及理解脂质相行为，蛋白质定位和功能以及膜脱髓鞘之间的关系提供洞察力。