Structural characterization of self-assembled inspired myelin sheath

complexes: biophysical perspective on adrenoleukodystrophy

The neuronal axons are enwrapped in myelin sheaths, a repeating multi-lamellar stack of lipid-rich membrane structure. The myelin sheaths act as an electrical insulator, forming a capacitor surrounding the axons and account functionally for fast nerve conduction in thin fibres [1]. In several neurodegenerative diseases, such as multiple sclerosis (MS) and adrenoleukodystrophy (ALD), the myelin sheaths are disrupted following neural dysfunction. Recently, we correlated the alteration of myelin's lipid stoichiometry found in MS patients to the transition from lamellar to inverted hexagonal phase in reconstituted myelin membrane [2]. Here, we wish to correlate similar phase transition as a result of alterations in the lipid`s hydrocarbon chain lengths as reported for ALD patients [3]. Comparison will be made between normal healthy lipid composition to diseased ALD one. In order to disclose the key physical interactions we aim to change gradually the distribution of the chain lengths, in addition to the temperature, which will allow future theoretical modelling. We will present our preliminary results conducted with our in-house SAXS. Clearly a major difference between native and modified lipid compositions is detected. The native lipid composition exhibits lamellar self-assembled structures, while the modified composition show coexisting of lamellar phase and inverted hexagonal phase.

1. Martenson RE (1992) Myelin--Biology and Chemistry CRC Press, Boca Raton, FL.

2. Shaharabani R, Ram-On M, Avinery R, Aharoni R, Arnon R, Talmon Y & Beck R (2016) Structural Transition in Myelin Membrane as Initiator of Multiple Sclerosis. J. Am. Chem. Soc.

3. Wilson R & Sargent J (1993) Lipid and fatty acid composition of brain tissue from adrenoleukodystrophy patients. J. Neurochem 61, 290–297.