Lysosome triggered near-infrared fluorescence imaging of cellular trafficking processes in real time

• Published in: Nature communications 2016-03, Vol.7 (1), p.10855-10855, Article 10855
• Main Authors: Grossi, Marco, Morgunova, Marina, Cheung, Shane, Scholz, Dimitri, Conroy, Emer, Terrile, Marta, Panarella, Angela, Simpson, Jeremy C., Gallagher, William M., O’Shea, Donal F.
• Format: Article
• Language: English
• Subjects: 14; 14/10; 14/19; 14/34; 14/35; 639/638/11/874; 639/638/309; 639/638/92; Adenocarcinoma - metabolism; Animals; Breast Neoplasms; Cell Communication; Cell Line, Tumor; Female; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; Humanities and Social Sciences; Humans; Lysosomes - metabolism; Mice; Microscopy, Fluorescence; Molecular Structure; multidisciplinary; Neoplasms, Experimental - metabolism; Optical Imaging - methods; Science; Science (multidisciplinary); Spectroscopy, Near-Infrared - methods
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms10855

Bioresponsive NIR-fluorophores offer the possibility for continual visualization of dynamic cellular processes with added potential for direct translation to in vivo imaging. Here we show the design, synthesis and lysosome-responsive emission properties of a new NIR fluorophore. The NIR fluorescent probe design differs from typical amine functionalized lysosomotropic stains with off/on fluorescence switching controlled by a reversible phenol/phenolate interconversion. Emission from the probe is shown to be highly selective for the lysosomes in co-imaging experiments using a HeLa cell line expressing the lysosomal-associated membrane protein 1 fused to green fluorescent protein. The responsive probe is capable of real-time continuous imaging of fundamental cellular processes such as endocytosis, lysosomal trafficking and efflux in 3D and 4D. The advantage of the NIR emission allows for direct translation to in vivo tumour imaging, which is successfully demonstrated using an MDA-MB-231 subcutaneous tumour model. This bioresponsive NIR fluorophore offers significant potential for use in live cellular and in vivo imaging, for which currently there is a deficit of suitable molecular fluorescent tools. Real time cellular fluorescence imaging requires a probe that displays high degrees of localisation, low toxicity and good photostability. Here, the authors report a near infrared fluorophore that displays pH-sensitive fluorescence based on phenol/phenolate interconversion, showing real time imaging of cellular processes.