Monitoring Mitophagy via the FRET Mechanism: Visualizing Mitochondria, Lysosomes, and Autolysosomes in Three Different Sets of Fluorescence Signals

Anal Chem. 2021 Jul 13;93(27):9471-9479. doi: 10.1021/acs.analchem.1c01237. Epub 2021 Jun 28.

Abstract

Mitophagy is a vital biological process playing central roles in the regulation of metabolic activity and quality control of mitochondria. The presented dual-color fluorescent probes to directly monitor mitophagy were based on the optical response to pH change during mitophagy, but pH fluctuation may lead to interference. To overcome this, herein, two fluorescent probes (G-Mito, R-Lyso) were rationally designed to visualize mitophagy directly in a dual-color manner, relying on the Förster resonance energy transfer (FRET) process for the first time. Green emissive G-Mito targeted and anchored the mitochondria via reaction with protein thiols. Red-emissive R-Lyso exclusively targeted lysosomes. Live cells loaded with the two probes demonstrated strong fluorescence in only the green channel with excitation at 405 nm. After mitophagy, G-Mito in mitochondria was delivered into the lysosomes, and red fluorescence evidently increased due to the FRET process. With the probes, mitochondria, lysosomes, and autolysosomes could be discriminatively visualized in three different sets of signals. Mitophagy induced by starvation and in normal physiological status were successfully observed. The probes revealed that a certain amount of H2O2 could induce mitophagy. We expect that the two probes can serve as molecular tools for validation of mitophagy and promote the development of related areas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fluorescence Resonance Energy Transfer*
  • Fluorescent Dyes / metabolism
  • Hydrogen Peroxide / metabolism
  • Lysosomes / metabolism
  • Mitochondria
  • Mitophagy*

Substances

  • Fluorescent Dyes
  • Hydrogen Peroxide