Browse
Submit Data
Databases
API
Help

Dataset Information

29 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A near-infrared fluorescent probe reveals decreased mitochondrial polarity during mitophagy† † Electronic supplementary information (ESI) available. See DOI: 10.1039/c9sc05505c

ABSTRACT: Mitophagy is a selective form of autophagy by which dysfunctional and damaged mitochondria are degraded in autolysosomes. Since defective mitophagy is closely related to various pathological processes, investigation on the detailed mitophagy process is of great importance. In this respect, disclosing the alterations of mitochondrial microenvironments is expected to be a promising way. However, an appropriate method for monitoring the fluctuations of mitochondrial polarity during mitophagy is still lacking. Here, we report a near-infrared hydroxyl-hemicyanine fluorescent probe that responds to polarity exclusively. Both the shift of emission maxima and the fluorescence intensity ratios at two different wavelengths of the probe can be applied to quantifying the polarity accurately. With ratiometric fluorescence imaging, the polarity differences of normal and cancer cells are clearly discriminated. Most importantly, the mitochondrial polarity variations during starvation and drug-induced mitophagy are determined for the first time. The observed decrease of mitochondrial polarity during mitophagy, together with the rationally designed probe, may facilitate the study on the vital role of mitophagy in physiological and pathological bioprocesses. A near-infrared mitochondria-targeting fluorescent probe has been developed to monitor the mitophagy-specific polarity dynamics in living cells.

SUBMITTER: Li X

PROVIDER: S-EPMC8148031 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

An ultrasensitive near-infrared ratiometric fluorescent probe for imaging mitochondrial polarity in live cells and in vivo.

Project description:Mitochondrial polarity is a crucial characteristic of these indispensable organelles, and tremendously impacts cellular events. Herein, we describe a new mitochondria-targeting fluorescent probe MCY-BF2 that is singularly sensitive and specifically responsive to mitochondrial polarity. The pull-push system in the conjugated structure of MCY-BF2 is responsible for the polarity-ultrasensitivity due to the excited state intramolecular charge transfer (ICT). By combining with cardiolipin, MCY-BF2 preferentially accumulates in mitochondria. Because the fluorescence emission wavelengths exhibit an obvious red-shift with increasing media polarity, the fluorescence intensity ratio at two different wavelengths versus the solvent dielectric constant can quantify the mitochondrial polarity. Experimental results demonstrate that the fluorescent intensity of MCY-BF2 in a non-polar solvent, dioxane, is 120 times higher than that in a polar solvent, dimethyl sulfoxide. As the first near-infrared (NIR) and most sensitive fluorescent imaging probe for polarity, MCY-BF2 can locate exclusively in mitochondria in various cells and discriminate polarity differences between normal and cancer cells. Also, the intrinsic polarity variance at different developmental stages in Caenorhabditis elegans (C. elegans) was reported here for the first time. Interestingly, the embryonic development stage has a more non-polar environment with a dielectric constant of 7.20, and in contrast the polarity at the young adult stage changes to 10.07. In addition, in vivo imaging results suggest that the tumor tissues of mice have an obviously lower polarity than that in normal tissues. Altogether, the merits of the NIR property, high sensitivity and moderate Stokes shift all greatly promote the accuracy of imaging. This probe will be a promising tool for studying biological processes and the pathological mechanism of polarity-related diseases.

| S-EPMC5964966 | biostudies-literature

Engineering of a near-infrared fluorescent probe for real-time simultaneous visualization of intracellular hypoxia and induced mitophagy.

Project description:Mitophagy induced by hypoxia plays an important role in regulating cellular homeostasis via the removal of dysfunctional mitochondria in the lysosomal degradation pathway, which results in physiological changes in the mitochondria, such as the pH, polarity and viscosity. However, the lack of an effective method for imaging of both the hypoxic microenvironment and the resulting variable mitochondria limits the visualization of hypoxia-induced mitophagy. Based on the specific mitochondrial pH changes during the hypoxia-induced mitophagy process, we have reported a near-infrared fluorescent probe (NIR-HMA) for real-time simultaneous visualization of the hypoxic microenvironment and the subsequent mitophagy process in live cells. NIR-HMA selectively accumulated in the hypoxic mitochondria in the NIR-MAO form, emitting at 710 nm, and then transformed into NIR-MAOH, emitting at 675 nm, in the acidified mitochondria-containing autolysosomes. Importantly, by smartly tethering the hypoxia-responsive group to the hydroxyl group of the NIR-fluorochrome, which shows ratiometric pH changes, NIR-HMA can differentiate between different levels of the hypoxic microenvironment and mitophagy. Furthermore, using NIR-HMA, we could track the complete mitophagy process from the mitochondria to the autolysosomes and visualize mitophagy caused only by hypoxia both in cancer cells and normal cells. Finally, NIR-HMA was applied to investigate the role that mitophagy plays in the hypoxic microenvironment via the cycling hypoxia-reoxygenation model. We observed a decreased fluorescence ratio after reoxygenation and a further increased mitophagy level after hypoxia was induced again, suggesting that mitophagy might be a self-protective process that allows cells to adapt to hypoxia. Our work may provide an attractive way for real-time visualization of relevant physiological processes in hypoxic microenvironments.

| S-EPMC6009437 | biostudies-literature

Near-infrared fluorescent probe for imaging of pancreatic beta cells.

Project description:The ability to image and ultimately quantitate beta-cell mass in vivo will likely have far reaching implications in the study of diabetes biology, in the monitoring of disease progression or response to treatment, and for drug development. Here, using animal models, we report on the synthesis, characterization, and intravital microscopic imaging properties of a near-infrared fluorescent exendin-4 analogue with specificity for the GLP-1 receptor on beta cells (E4(K12)-Fl). The agent demonstrated subnanomolar EC(50) binding concentrations, with high specificity and binding that could be inhibited by GLP-1R agonists. Following intravenous administration to mice, pancreatic islets were readily distinguishable from exocrine pancreas, achieving target-to-background ratios within the pancreas of 6:1, as measured by intravital microscopy. Serial imaging revealed rapid accumulation kinetics (with initial signal within the islets detectable within 3 min and peak fluorescence within 20 min of injection), making this an ideal agent for in vivo imaging.

| S-EPMC2912453 | biostudies-literature

A Ultrasensitive Near-Infrared Fluorescent Probe Reveals Pyroglutamate Aminopeptidase 1 Can Be a New Inflammatory Cytokine.

Project description:Previous study showed that pyroglutamate aminopeptidase 1 (PGP-1) has a relationship with the immune response in cells. However, whether PGP-1 is involved in inflammatory response in vivo and can serve as a new inflammatory cytokine are still unclear. To address these issues, a new near-infrared fluorescent probe, which exhibits high selectivity and super sensitivity, is developed. With this probe, the up-regulation of PGP-1 (evidenced by western blot) in BALB/c mice legs and livers under the stimulation of two main immunopotentiators is revealed for the first time. The occurrence of inflammatory process (including tissue necrosis) in mice is determined by up-regulation of tumor necrosis factor-α and hematoxylin-eosin staining. Interestingly, it is revealed for the first time that knocking down PGP-1 leads to the weakness of inflammatory process in RAW264.7 cells. These new findings suggest that PGP-1 is indeed involved in inflammatory response in vivo and can be a new inflammatory cytokine.

| S-EPMC5908353 | biostudies-literature

A ratiometric near-infrared fluorescent probe based on a novel reactive cyanine platform for mitochondrial pH detection.

Project description:A near-infrared reactive cyanine platform (probe A) was prepared by condensation of 9-chloro-1,2,3,4-tetrahydro-10-methyl-acridinium iodide with Fisher's aldehyde. A near-infrared fluorescent probe (probe B) was prepared by modifying a reactive chlorine atom of probe A with tert-butyl(2-aminoethyl)carbamate through a substitution reaction. The deprotection of the Boc group of probe B was achieved under an acidic condition, affording an amine-functionalized cyanine dye (probe C). A near-infrared ratiometric fluorescent probe (probe D) for mitochondrial pH detection was synthesized by conjugating a FRET coumarin donor to a FRET cyanine acceptor (probe C) through an amide bond connection. Probe A shows low fluorescence of 2% due to an electron-withdrawing chlorine atom, while probes B-D display high fluorescence quantum yields of 60%, 32%, and 35% in aqueous solutions containing 10% ethanol, respectively. Probes B-D show strong fluorescence with push-pull molecular structures in neutral and basic pH conditions. However, protonation of the probe's second amine at the 9-position under acidic condition disrupts the push-pull feature of the probes, resulting in fluorescence quenching of the new cyanine fluorophores. The probes can selectively stain mitochondria, while probe D was employed to detect pH changes in HeLa cells and Drosophila melanogaster first-instar larvae.

| S-EPMC8265329 | biostudies-literature

A high-affinity near-infrared fluorescent probe to target bombesin receptors.

Project description:PURPOSE:This study aimed to create new optical surgical navigation NIRF probes for prostate and breast cancers. PROCEDURES:IR800-linker-QWAVGHLM-NH2 with linker = GSG, GGG, and G-Abz4 were synthesized and characterized. IC50 for bombesin receptors (BBN-R) in PC-3 prostate and T47D breast cancer cells, fluorescence microscopy in PC-3 cells, and NIRF imaging in mice PC-3 tumor xenografts were studied. RESULTS:GGG, GSG, and G-Abz4 derivatives had IC50 (nM) for BBN-R+ PC-3 cells?=?187?±?31, 56?±?5, and 2.6?±?0.2 and T47D cells?=?383?±?1, 57.4?±?1.2, and 3.1?±?1.1, respectively. By microscopy the Abz4 derivative showed the highest uptake, was competed with by BBN, and had little to no binding to BBN-R- cells. In NIRF imaging the G-Abz4 probe was brighter than GGG probe in BBN-R+ tissues in vivo and tissues, tumors, and tumor slices ex vivo. Uptake could be partially blocked in BBN-R+ pancreas but not visibly in tumor. CONCLUSIONS:Linker choice can dominate peptidic BBN-R binding. The G-Abz4 linker yields a higher affinity and specific BBN-R binder in this series of molecules.

| S-EPMC5885141 | biostudies-literature

Near-Infrared Fluorescent pH Responsive Probe for Targeted Photodynamic Cancer Therapy.

Project description:We developed a pH dependent amino heptamethine cyanine based theranostic probe (I2-IR783-Mpip) that can be activated by near infrared light. I2-IR783-Mpip, in acidic condition, exhibited an intense, broad NIR absorption band (820-950 nm) with high singlet oxygen generation upon exposure to NIR light (~850 nm). Theoretical calculations showed that the protonation of the probe in an acidic environment decreased the molecular orbital energy gaps and increased the intramolecular charge transfer efficiency. I2-IR783-Mpip exhibited good photodynamic efficiency towards liver hepatocellular carcinoma cells under physiological and slightly acidic conditions while normal human embryonic kidney cells remained alive under the same conditions. Detection of intracellular reactive oxygen species (ROS) in cells treated with I2-IR783-Mpip after NIR light exposure confirmed PDT efficiency of the probe in acidic environment. Moreover, I2-IR783-Mpip also demonstrated efficient phototoxicity under deep-seated tumour cell system. We believed this is the first PDT agent that possesses intrinsic tumour binding and selectively eradicate tumour in acidic environment under 850 nm NIR lamp.

| S-EPMC6987190 | biostudies-literature

A Simple Near-Infrared Fluorescent Probe for the Detection of Peroxynitrite.

Project description:Herein, we report the evaluation and synthesis of a reaction based fluorescent probe DCM-Bpin for the detection of Peroxynitrite (ONOO-). DCM-Bpin exhibits selective fluorescence off-on response for ONOO- over other reactive oxygen species, including H2O2. Moreover, DCM-Bpin is biocompatible and has been used to visualize exogenous ONOO- in HeLa cells.

| S-EPMC6900745 | biostudies-literature

A near-infrared fluorescent probe based on a hemicyanine dye with an oxazolidine switch for mitochondrial pH detection.

Project description:A near-infrared fluorescent probe (AH+) has been prepared by incorporating an oxazolidine switch into a near-infrared hemicyanine dye. The probe shows fast and sensitive responses to pH from an oxazolidine switch to the hemicyanine dye upon pH decreases from 10.0 to 5.0. The probe shows good photostability, low cytotoxicity, and reversible fluorescence responses to pH changes with a pKa value of 7.6. It has been successfully used to determine pH changes in mitochondria.

| S-EPMC7855747 | biostudies-literature