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）（一种已建立的多发性硬化症动物模型）过程中，脑髓磷脂的脂质成分发生了潜在的重要变化。正常脂质和 EAE 脂质的细胞质和细胞外单层的组织（结构）不同。这些“相行为”的差异导致了我们使用表面力装置（SFA）观察到的髓磷脂膜之间相互作用力的差异，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是由于与脂质成分偶联的髓磷脂碱性蛋白（MBP），其中阴离子脂质和蛋白质亚型含量尤其重要。膜的细胞外侧之间的相互作用完全归因于脂质，因为该侧没有已知的粘附蛋白。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，这也应该受到EAE膜中脂质的相行为和分布的改变的强烈影响。 SFA 将用于研究正常和 EAE 髓磷脂的完整力与距离曲线，以将成分和相行为变化与将髓鞘的细胞外侧和细胞质侧固定在一起的相互作用力联系起来。除了脂质组成的变化之外，还将使用 SFA 确定不同 MBP 亚型（C1、C3、C8）对膜粘附的影响，以显示这些亚型如何与脂质分布耦合。我们将使用朗缪尔等温线和模型细胞质和细胞外单层和双层的荧光显微镜来确定脂质组成和横向相分离之间的关系。我们对胆固醇、阴离子脂质磷脂酰丝氨酸和鞘磷脂以及中性脂质磷脂酰胆碱特别感兴趣，它们在对照和 EAE 髓磷脂之间显示出最大的差异。原子力显微镜 (AFM) 将同时用于研究脂质和 MBP 及其亚型在纳米尺度的分布。我们假设聚乙二醇 (PEG) 和泊洛沙姆（FDA 批准的无毒聚合物）最近用于治疗动物脊髓损伤，可能通过增加有吸引力的渗透“耗竭”力来治愈髓鞘，从而提供类似的作用。我们最近观察到的 MBP 效应。这项工作将深入了解膜组成和组织在导致 MS 的相互作用中的作用，以及理解脂相行为、蛋白质定位和功能以及膜脱髓鞘之间关系的基本进展。