Engineering a Viscosity-Gated Dual-Rotor Probe for Comprehensive Mapping of Lipid Droplet Heterogeneity

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Imaging

Background:

• Lipid droplets (LDs) are crucial in lipid metabolism and disease.
• Small, highly viscous LDs are metabolically active but difficult to study.
• Conventional probes have limitations in visualizing LD heterogeneity.

Purpose of the Study:

• To develop a novel fluorophore for high-fidelity imaging of LDs.
• To investigate LD heterogeneity and metabolic states using the new probe.
• To enable subcellular resolution of lipid remodeling in disease.

Main Methods:

• Design and synthesis of YTT-Z, a viscosity-gated dual-rotor fluorophore.
• Optimization of YTT-Z for fixed-cell imaging and ratiometric analysis.
• Application of YTT-Z in diverse cell types to map LDs and their metabolic status.

Main Results:

• YTT-Z exhibits enhanced brightness, photostability, and microviscosity sensitivity.
• Selective accumulation of YTT-Z in LD cores reveals small, high-viscosity LD subpopulations.
• YTT-Z uncovers mitochondria-associated LDs and spatial variations in LD metabolic status.

Conclusions:

• YTT-Z is a powerful new tool for dissecting LD substructures and metabolic gradients.
• The probe facilitates studies on organelle mapping and lipid metabolism.
• YTT-Z aids in understanding disease-linked lipid remodeling at subcellular resolution.