Simultaneous visualization of lipid droplets and lysosomes using a single fluorescent probe

Abstract

Lipid droplets (LDs) and lysosomes, as the important subcellular organelles, play vital roles in cell metabolism and physiology. The finding that LDs can be degraded by lysosomes through lipophagy demonstrated the communication between LDs and lysosomes. Thus, simultaneous visualization of LDs and lysosomes is extremely valuable for studying the LD-lysosome interplay. However, single fluorescent probe for simultaneous imaging LDs and lysosomes in live cells and tissues has been rarely reported. Herein, we developed a polarity-sensitive naphthalimide derivative LD-Lys as fluorescent probe with high photostability and low cytotoxicity. Due to its TICT feature, LD-Lys is highly sensitive to the nuance of polarity between LDs and lysosomes, and show strong and weak fluorescence, respectively. The simultaneous two-color imaging of LDs with bright yellow emission and lysosomes with weak red emission is also realized by using the Lambda mode of confocal laser scanning microscope. By monitoring the location changes, real-time tracking the movement of LDs and lysosomes in cells by LD-Lys could be visualized. Interestingly, the size, morphology and distribution of LDs and lysosomes in different tissues could be also visualized clearly. These excellent properties made LD-Lys a promising fluorescent agent for studying the LD-lysosome interplay and metabolism diseases.