Lysosomal Targeting with Stable and Sensitive Fluorescent Probes (Superior LysoProbes): Applications for Lysosome Labeling and Tracking during Apoptosis

Abstract

Intracellular pH plays an important role in the response to cancer invasion. We have designed and synthesized a series of new fluorescent probes (Superior LysoProbes) with the capacity to label acidic organelles and monitor lysosomal pH. Unlike commercially available fluorescent dyes, Superior LysoProbes are lysosome-specific and are highly stable. The use of Superior LysoProbes facilitates the direct visualization of the lysosomal response to lobaplatin elicited in human chloangiocarcinoma (CCA) RBE cells, using confocal laser scanning microscopy. Additionally, we have characterized the role of lysosomes in autophagy, the correlation between lysosome function and microtubule strength, and the alteration of lysosomal morphology during apoptosis. Our findings indicate that Superior LysoProbes offer numerous advantages over previous reagents to examine the intracellular activities of lysosomes.

Discerning the Chemistry in Individual Organelles with Small‐Molecule Fluorescent Probes

“…[120,122] To monitor lysosomal enzymes,T ang, Liu, and co-workers recently designed asimple fluorescent probe (AIE-Lyso-1 (67), Scheme 25) that could specifically react with esterases in an acidic environment. [120,122,156] Hence as eries of LyTAFPs for pH value have been generated. In the absence of esterases,t he probe could freely rotate,t hereby dissipating the excited energy;i nt he presence of esterases, the acetoxy groups attached to the probe were removed, thereby leaving hydroxy groups that were able to form hydrogen bonds with the hydrazine,t hus locking the structure.I nt his manner,t he probe could be lit up within the lysosome compartment, as demonstrated by live cell imaging.The majority of the enzymes within the lysosome require an acidic environment to function properly,a nd fluctuations in the lysosomal pH values are usually outcomes of diseases.T herefore,r eal-time monitoring of the lysosomal pH value could facilitate disease diagnosis.…”

“…[155] Thel ysosomal pH value is av ital parameter to maintain normal digestive functions,and minor pH fluctuations may influence av ariety of physiological processes. [120,122,156] Hence as eries of LyTAFPs for pH value have been generated. [157] Aprominent example by the Ma research group features ap H-responsive probe based on the hemicyanine-xanthene combination (Lyso-pH (68), Scheme 25).…”

Exploring cells with targeted biosensors

“…Membrane potential Ca 2+ (Hajnóczky et al, 1995) Zn 2+ Sreenath et al, 2011;Liu et al, 2012b;Chyan et al, 2014) thiols H 2 O 2 (Dickinson and Chang, 2008) pH (Sarkar et al, 2016) superoxide (Robinson et al, 2006) membrane potential (Nicholls, 2012) Acidic compartments pH gradient, endocytosis pH Miao et al, 2013;Lv et al, 2014;Chen et al, 2015;Wang et al, 2015;Yapici et al, 2015) thiols (Kand et al, 2015) Ca 2+ (Gilroy and Jones, 1992;Schlatterer et al, 1992) vesicle recycling (Gaffield and Betz, 2007;Li et al, 2009) neurotransmitter release (Gubernator et al, 2009) At resting negative membrane potential (top), the permeable oxonols have a high concentration at the extracellular surface of the PM, and energy transfer from the extracellularly bound FL-WGA (acceptor molecule) is favored. FRET is symbolized as the fluorescent changes are small, and repetitive measurements are needed to obtain a good record of action potentials (for recent reviews see Peterka et al [2011] and St-Pierre et al [2015]).…”

MemBright: a Family of Fluorescent Membrane Probes for Advanced Cellular Imaging and Neuroscience

“…4, 5 The key challenge in cellular imaging is to stain cell compartments with high specificity and persistence. Although numerous efficient molecular probes have been designed to selectively stain specific cellular structures including mitochondria, 6 lipid droplets 7 , endoplasmic reticulum 8 , nucleus 7 and lysosomes 10–11 ,there is still a demand for efficient and bright fluorescent PM markers. 12 Fluorescently labelled lectins notably wheat germ agglutinin (WGA) and concanavalin A 9 are popular fluorescent membrane probes.…”