Melatonin-Induced Modulation of Cholesterol-Enriched Model Neuronal Membranes

Area of Science:

• Neuroscience
• Biophysics
• Biochemistry

Background:

• Melatonin regulates circadian rhythms and affects neuronal membrane properties.
• Its amphiphilic nature allows integration into lipid bilayers and interaction with lipid rafts.
• The molecular basis of melatonin's interaction with different lipid phases is not well understood.

Purpose of the Study:

• To investigate the molecular mechanisms of melatonin's interaction with coexisting liquid-ordered (L_o) and liquid-disordered (L_d) phases in model neuronal membranes.
• To elucidate melatonin's role in modulating membrane heterogeneity and its receptor-independent actions.

Main Methods:

• Small-angle neutron scattering (SANS) was used to analyze model neuronal membranes.
• All-atom molecular dynamics simulations were employed to examine membrane-melatonin interactions.
• Model membranes were composed of DSPC, DOPC, POPC, and cholesterol.

Main Results:

• Melatonin incorporates into lipid bilayers and adopts distinct orientations within the membrane.
• It interacts with both liquid-ordered and liquid-disordered lipid phases, bridging across them.
• Melatonin preserves the domain morphology of the neuronal membranes.

Conclusions:

• Melatonin modulates neuronal membrane heterogeneity through direct interaction with lipid phases.
• These findings support melatonin's receptor-independent membrane-associated functions.
• Understanding melatonin's membrane activity provides insights into its neuroprotective roles.