Using electron and confocal microscopy we recently showed that prolonged sleep restriction (~5 days) reduced myelin thickness and increased node of Ranvier length without affecting internodal length, thus suggesting that sleep loss can lead to plastic remodeling of myelin. Since optimal plasma membrane fluidity is an essential requirement for cellular plasticity, we hypothesized that the fluidity of membranes forming myelin could be affected by sleep loss. Membrane fluidity of myelin enriched brain samples from sleeping (S, n=6, killed after 6 hrs of sleep during the light cycle) and sleep deprived C57BL/6 mice (SD, n=6, killed after 4 hrs of enforced wake during the light cycle) was assessed by steady-state fluorescence spectroscopy. Two fluorophores were used, 2-dimethylamino-(lauroyl)-naphtalene (Laurdan) located at hydrophobic-hydrophilic interface of the membrane, and 1,6 diphenyl-1,3,5-hexatriene, incorporated in hydrophobic lipid region. Moreover, in mouse forebrain samples, genome-wide analysis of messenger RNA profiling of oligodendrocyte lineage was conducted as a function of S and SD to detect differentially expressed genes. A significant increase in membrane fluidity was found in myelin membrane core in SD relative to S (DPH anisotropy: S [0.231±0.008]; SD [0.222±0.005], p<0.00019), while no differences were detected at the polar headgroups level. In addition, analysis of the oligodendroglia transcriptome revealed the up-regulation of Fad3 in SD (+176%; p=0.004). Fad3 codes for a fatty acid desaturase that regulates unsaturation of fatty acids and thus influences membrane fluidity. In conclusion, increased fluidity of the inner myelin membrane region could contribute to morphological modifications of myelin induced by sleep loss.

Sleep loss increases membrane fluidity of myelin sheaths / ABOUFARES EL ALAOUI, Amina; Fiorini, R.; Fabri, M.; Bellesi, M.. - ELETTRONICO. - (2019). (Intervento presentato al convegno Neuroscience 2019 tenutosi a Chicago, Illinois, USA nel October 19-23, 2019).

Sleep loss increases membrane fluidity of myelin sheaths

ABOUFARES EL ALAOUI, AMINA;R. FIORINI;M. FABRI;
2019-01-01

Abstract

Using electron and confocal microscopy we recently showed that prolonged sleep restriction (~5 days) reduced myelin thickness and increased node of Ranvier length without affecting internodal length, thus suggesting that sleep loss can lead to plastic remodeling of myelin. Since optimal plasma membrane fluidity is an essential requirement for cellular plasticity, we hypothesized that the fluidity of membranes forming myelin could be affected by sleep loss. Membrane fluidity of myelin enriched brain samples from sleeping (S, n=6, killed after 6 hrs of sleep during the light cycle) and sleep deprived C57BL/6 mice (SD, n=6, killed after 4 hrs of enforced wake during the light cycle) was assessed by steady-state fluorescence spectroscopy. Two fluorophores were used, 2-dimethylamino-(lauroyl)-naphtalene (Laurdan) located at hydrophobic-hydrophilic interface of the membrane, and 1,6 diphenyl-1,3,5-hexatriene, incorporated in hydrophobic lipid region. Moreover, in mouse forebrain samples, genome-wide analysis of messenger RNA profiling of oligodendrocyte lineage was conducted as a function of S and SD to detect differentially expressed genes. A significant increase in membrane fluidity was found in myelin membrane core in SD relative to S (DPH anisotropy: S [0.231±0.008]; SD [0.222±0.005], p<0.00019), while no differences were detected at the polar headgroups level. In addition, analysis of the oligodendroglia transcriptome revealed the up-regulation of Fad3 in SD (+176%; p=0.004). Fad3 codes for a fatty acid desaturase that regulates unsaturation of fatty acids and thus influences membrane fluidity. In conclusion, increased fluidity of the inner myelin membrane region could contribute to morphological modifications of myelin induced by sleep loss.
2019
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11566/271397
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