Lipid-Conjugated Rigidochromic Probe Discloses Membrane Alteration in Model Cells of Krabbe Disease

Area of Science:

• Cell Biology
• Biophysics
• Neuroscience

Background:

• Cell membranes feature distinct lipid domains (L_o and L_d) influencing cellular functions.
• Understanding these domains is crucial for cellular health and disease mechanisms.

Purpose of the Study:

• To develop a method for quantifying ordered (L_o) and disordered (L_d) membrane domains in living cells.
• To investigate the effects of galactosylsphingosine (psychosine) on oligodendrocyte plasma membrane composition.

Main Methods:

• Utilized a novel fluorescent analog of the green fluorescent protein chromophore conjugated to a phospholipid.
• Employed phasor analysis of confocal fluorescence lifetime imaging for domain quantification.
• Applied the technique to human oligodendrocytes at rest and treated with psychosine.

Main Results:

• The fluorescent probe enabled direct quantification of L_o and L_d domains.
• Psychosine treatment led to a progressive destabilization of the plasma membrane.
• A significant reduction in the L_o lipid domain fraction was observed upon psychosine administration.

Conclusions:

• The developed imaging strategy accurately quantifies membrane domain composition in living cells.
• Psychosine directly alters plasma membrane structure by reducing ordered lipid domains, recapitulating aspects of Krabbe disease.
• This provides insights into the physical mechanisms underlying globoid cell leukodystrophy pathogenesis.