Visualization of lipophagy using a supramolecular FRET pair

Area of Science:

• Biochemistry
• Cell Biology
• Supramolecular Chemistry

Background:

• Autophagy is a crucial cellular process for degrading and recycling cellular components.
• Selective autophagy targets specific organelles like lipid droplets (LDs) for degradation.
• Visualizing organelle-specific autophagy, such as lipophagy, remains challenging.

Purpose of the Study:

• To develop a novel supramolecular imaging tool for visualizing organelle-specific autophagy.
• To demonstrate the application of a rationally designed FRET pair for tracking lipophagy.
• To investigate the potential of bio-orthogonal host-guest interactions in cellular imaging.

Main Methods:

• Design and synthesis of a Förster Resonance Energy Transfer (FRET) pair: cyanine3-cucurbit[7]uril (Cy3-CB[7]) and boron-dipyrromethene 630/650-adamantylammonium (BDP-AdA).
• Utilizing the specific intracellular localization of Cy3-CB[7] in lysosomes and BDP-AdA in LDs.
• Observing FRET signal generation upon the formation of an intracellular host-guest complex between Cy3-CB[7] and BDP-AdA.

Main Results:

• Cy3-CB[7] selectively accumulated in lysosomes, while BDP-AdA localized to LDs.
• Formation of a supramolecular host-guest complex between Cy3-CB[7] and BDP-AdA was observed intracellularly.
• Successful visualization of LD-lysosome fusion (lipophagy) through FRET signal detection.

Conclusions:

• The developed supramolecular FRET pair enables visualization of organelle-specific autophagy events.
• Supramolecular imaging based on bio-orthogonal host-guest interactions is a powerful tool for studying selective autophagy.
• This approach provides new insights into the mechanisms of lipophagy and other selective autophagy pathways.