Quinone-Derived π-Extended Phenazines as New Fluorogenic Probes for Live-Cell Imaging of Lipid Droplets.

Fabio de Moliner,Aaron King,Carlos A de Simone,Eufrânio N da Silva Júnior,Gleiston G Dias,Guilherme F de Lima,Marc Vendrell

doi:10.3389/fchem.2018.00339

Abstract

We describe a new synthetic methodology for the preparation of fluorescent π-extended phenazines from the naturally-occurring naphthoquinone lapachol. These novel structures represent the first fluorogenic probes based on the phenazine scaffold for imaging of lipid droplets in live cells. Systematic characterization and analysis of the compounds in vitro and in cells led to the identification of key structural features responsible for the fluorescent behavior of quinone-derived π-extended phenazines. Furthermore, live-cell imaging experiments identified one compound (P1) as a marker for intracellular lipid droplets with minimal background and enhanced performance over the lipophilic tracker Nile Red.

Highlights

Lipid droplets (LDs) are ubiquitous intracellular organelles which represent the main storage of fatty acids and neutral lipids within the cytoplasm (Martin and Parton, 2006; Farese and Walther, 2009)
LDs have a close relationship with endoplasmic reticulum, in a fashion which strongly points at the existence of an extensive lipids trafficking between these two subcellular compartments (Robenek et al, 2006)
The new fluorescent π-extended phenazines were prepared according to the synthetic procedures shown in Scheme 2

Summary

Introduction

Lipid droplets (LDs) are ubiquitous intracellular organelles which represent the main storage of fatty acids and neutral lipids within the cytoplasm (Martin and Parton, 2006; Farese and Walther, 2009). As such, they display the unique feature of containing highly hydrophobic phases within the aqueous environment of the cytosol (Walther and Farese, 2012). LDs have a close relationship with endoplasmic reticulum, in a fashion which strongly points at the existence of an extensive lipids trafficking between these two subcellular compartments (Robenek et al, 2006) This phenomenon involves complex mechanisms that still need to be fully elucidated (Martin et al, 2005).

Methods

Results

Conclusion