Ratiometric and discriminative visualization of autophagic processes with a novel dual-responded lysosome-specific fluorescent probe.

Content Provider	Europe PMC
Author	Zheng, Fan Ma, Yeshuo Ding, Jipeng Huang, Shuai Zhang, Shengwang Huang, Xueyan Feng, Bin Zeng, Hongliang Chen, Fei Zeng, Wenbin
Abstract	BackgroundAutophagy is a critical self-eating pathway involved in numerous physiological and pathological processes. Lysosomal degradation of dysfunctional organelles and invading microorganisms is central to the autophagy mechanism and essential for combating disease-related conditions. Therefore, monitoring fluctuations in the lysosomal microenvironment is vital for tracking the dynamic process of autophagy. Although much effort has been put into designing probes for measuring lysosomal viscosity or pH separately, there is a need to validate the concurrent imaging of the two elements to enhance the understanding of the dynamic progression of autophagy.MethodsProbe HFI was synthesized in three steps and was developed to visualize changes in viscosity and pH within lysosomes for real-time autophagy tracking. Then, the spectrometric determination was carried out. Next, the probe was applied to image autophagy in cells under nutrient-deprivation or external stress. Additionally, the performance of HFI to monitor autophagy was employed to evaluate acetaminophen-induced liver injury.ResultsWe constructed a ratiometric dual-responsive probe, HFI, with a large Stokes shift over 200 nm, dual-wavelength emission, and small background interference. The ratiometric fluorescent signal (R = I 610/I 460) of HFI had an excellent correlation with both viscosity and pH. More importantly, high viscosity and low pH had a synergistic promotion effect on the emission intensity of HFI, which enabled it to specially lit lysosomes without disturbing the inherent microenvironment. We then successfully used HFI to monitor intracellular autophagy induced by starvation or drugs in real-time. Interestingly, HFI also enabled us to visualize the occurrence of autophagy in the liver tissue of a DILI model, as well as the reversible effect of hepatoprotective drugs on this event.ConclusionsIn this study, we developed the first ratiometric dual-responsive fluorescent probe, HFI, for real-time revealing autophagic details. It could image lysosomes with minimal perturbation to their inherent pH, allowing us to track changes in lysosomal viscosity and pH in living cells. Ultimately, HFI has great potential to serve as a useful indicator for autophagic changes in viscosity and pH in complex biological samples and can also be used to assess drug safety.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40824-023-00409-3.
Related Links	https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC10327318&blobtype=pdf
ISSN	12264601
Journal	Biomaterials Research [Biomater Res]
Volume Number	27
DOI	10.1186/s40824-023-00409-3
PubMed Central reference number	PMC10327318
Issue Number	1
PubMed reference number	37415205
e-ISSN	20557124
Language	English
Publisher	BioMed Central
Publisher Date	2023-07-06
Publisher Place	London
Access Restriction	Open
Rights License	Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. © The Author(s) 2023
Subject Keyword	Autophagy visualization Fluorescent probe Lysosome-specific Ratiometric imaging Dual-responsive pH Viscosity Acetaminophen-induced liver injury
Content Type	Text
Resource Type	Article
Subject	Ceramics and Composites Medicine Biomaterials Biomedical Engineering