Simultaneous and discriminative visualization of endoplasmic reticulum and lysosomes in apoptosis and autophagy using a single fluorescent probe

The interplay of organelles plays indispensable roles in various biological processes, and their precise interactions contribute to a series of biological functions. Therefore, the exploitation of single probes capable of simultaneously visualizing two organelles is significant yet challenging. In this study, a novel fluorescent probe able to visualize both the endoplasmic reticulum (ER) and lysosomes concurrently was utilized to monitor apoptosis and autophagy. Leveraging the photoinduced electron transfer (PET) mechanisms, the probe (named EL) demonstrated distinct variations in fluorescent intensity within solutions of different pH levels, which enables the differentiation of ER and lysosomes due to their diverse pH values. EL was also effective in monitoring apoptosis with a decrease in fluorescent intensity, and it could visualize the increase of fluorescent intensity in autophagy. Consequently, the discrimination of apoptosis and autophagy processes was achieved. The potential applications of EL in visualizing ER and lysosomes and tracking their dynamic changes during various physiological processes are significant, so this probe would prompt the development of physiology and pathology related to ER and lysosomes.