Adenosine triphosphate (ATP) is used as the energy source in cells and plays crucial roles in various cellular events. The cellular membrane is the protective barrier for the cytoplasm of living cells and involved in many essential biological processes. Many fluorescent probes for ATP have been successfully developed, but few of these probes were appropriate for visualizing ATP level fluctuation in cell membranes during the apoptotic cell death process. Herein, we report the synthesis of a new water-soluble cationic polythiophene derivative that can be utilized as a fluorescent sensor for detecting ATP in cell membranes. Poly((3-((4-methylthiophen-3-yl)oxy)propyl)triphenylphosphonium chloride) (PMTPP) exhibits high sensitivity and good selectivity to ATP, and the detection limit is 27 nM. The polymer shows low toxicity to live cells and excellent photostability in cell membranes. PMTPP was practically utilized for real-time monitoring of ATP levels in the cell membrane through fluorescence microscopy. We have demonstrated that the ATP levels in cell membranes increased during the apoptotic cell death process. The probe was also capable of imaging ATP levels in living mice.

•F482 was applied in ratiometrically detecting ONOO-.•Carboxylic BODIPY formation by ONOO--induced diene oxidation was confirmed.•F482 enables us to quantify ONOO- in phagosomes by high-throughput flow cytometry.•Visualizing and quantifying ONOO- fluxes in mouse inflammation model was realized.Reactions of peroxynitrite (ONOO−) with biomolecules can lead to cytotoxic and cytoprotective events. Due to the difficulty of directly and unambiguously measuring its levels, most of the beneficial effects associated with ONOO− in vivo remain controversial or poorly characterized. Recently, optical imaging has served as a powerful noninvasive approach to studying ONOO− in living systems. However, ratiometric probes for ONOO− are currently lacking. Herein, we report the design, synthesis, and biological evaluation of F482, a novel fluorescence indicator that relies on ONOO−-induced diene oxidation. The remarkable sensitivity, selectivity, and photostability of F482 enabled us to visualize basal ONOO− in immune-stimulated phagocyte cells and quantify its generation in phagosomes by high-throughput flow cytometry analysis. With the aid of in vivo ONOO− imaging in a mouse inflammation model assisted by F482, we envision that F482 will find widespread applications in the study of the ONOO− biology associated with physiological and pathological processes in vitro and in vivo.

We developed a dual-target theranostic F671, which could exhibit synergetic anticancer effects for inhibiting the activities of glutathione S-transferase and the accumulation of hypoxia inducible factor-1α. F671 undergoes self-immolative cleavage when exposed to GSTP1-1 in live cancer cells, facilitating the visualization of molecule release and distribution, as well as confirming the autophagy-induced apoptosis.

•PEMTEI is the first fluorescent probe for the detection of ATP in lysosome.•PEMTEI exhibits high selectivity and sensitivity to ATP in physiological conditions.•PEMTEI has low cytotoxicity, good permeability and high photostability in cells.•Lysosomes in HeLa cells can release ATP through Ca2+-dependent exocytosis.Lysosomes in astrocytes and microglia can release ATP as the signaling molecule for the cells through ca2+-dependent exocytosis in response to various stimuli. At present, fluorescent probes that can detect ATP in lysosomes have not been reported. In this work, we have developed a new water-soluble cationic polythiophene derivative that can be specifically localized in lysosomes and can be utilized as a fluorescent probe to sense ATP in cells. PEMTEI exhibits high selectivity and sensitivity to ATP at physiological pH values and the detection limit of ATP is as low as 10−11 M. The probe has low cytotoxicity, good permeability and high photostability in living cells and has been applied successfully to real-time monitoring of the change in concentrations of ATP in lysosomes though fluorescence microscopy. We also demonstrated that lysosomes in Hela cells can release ATP through Ca2+-dependent exocytosis in response to drug stimuli.

To enhance the therapeutic effects and decrease the adverse effects of arsenic on the treatment of acute promyelocytic leukemia, we investigated the co-effects of selenite (Se4+) and arsenite (As3+) on the apoptosis and differentiation of NB4 cells and primary APL cells. A 1.0-μM concentration of Se4+ prevented the cells from undergoing As3+-induced apoptosis by inhibiting As3+ uptake, eliminating As3+-generated reactive oxygen species, and repressing the mitochondria-mediated intrinsic apoptosis pathway. However, 4.0 μM Se4+ exerted synergistic effects with As3+ on cell apoptosis by promoting As3+ uptake, downregulating nuclear factor-кB, and activating caspase-3. In addition to apoptosis, 1.0 and 3.2 μM Se4+ showed contrasting effects on As3+-induced differentiation in NB4 cells and primary APL cells. The 3.2 μM Se4+ enhanced As3+-induced differentiation by promoting the degradation of promyelocytic leukemia protein–retinoic acid receptor-α (PML–RARα) oncoprotein, but 1.0 μM Se4+ did not have this effect. Based on mechanistic studies, Se4+, which is similar to As3+, might bind directly to Zn2+-binding sites of the PML RING domain, thus controlling the fate of PML–RARα oncoprotein.

Rare-earth doped UCNPs with a carboxyl coating on the surface have been widely used in many fields of biology, however, the modification of nanoparticles with a carboxyl polymer group is relatively complicated, and thus, fabricating carboxyl polymer-coated UCNPs using a simple method is significant. Herein, we synthesized carboxyl polymer-coated NaYF4:Yb3+/Tm3+ nanoparticles through a hydrothermal route during which methacrylic acid polymerized and bound to the surface of the nanoparticles. Dependence of structure and morphology on the dosage of NaOH was investigated. The polymerization degree of poly(methacrylic acid) and the amount of capping carboxyl group influenced by the dosage of NaOH were also studied. Other carboxyl-functionalized rare-earth fluorides could be obtained by using this method, the mechanism for which was also investigated. Thus, this method was universal for the carboxyl capping of rare-earth doped fluoride nano-materials, and also provided a new approach for carboxylic functionalization of nanoparticles. cis-Dichlorodiammineplatinum(II) (cisplatin, CDDP)-loaded NaYF4:Yb3+/Tm3+ nanoparticles (NaYF4–CDDP) were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, and CDDP was loaded in the form of Pt–O bonds. Upconversion luminescence images revealed the time course of intracellular CDDP delivery by NaYF4–CDDP. Compared with CDDP alone, the NaYF4–CDDP composite exerted cytotoxic effects on HeLa and MCF-7 cancer cell lines depending more on time and more slowly due to time-dependent cellular uptake and drug release. Non-loaded NaYF4:Yb3+/Tm3+ nanoparticles were also eligible for upconversion luminescence cell imaging. Therefore, the as-prepared NaYF4:Yb3+/Tm3+ nanoparticles allow simultaneous cell imaging and drug delivery as promising anti-cancer theranostic agents.

•A fluorescence assay of ATPS activity based on PPi probe was established firstly.•A fluorescence assay of ALP activity based on PPi probe was established.•[(ZnL)2–PPi] can be used to screen potentially ALP and ATPS inhibitors.An anthracene-armed tetraaza macrocyclic fluorescent probe 3-(9-anthrylmethyl)-3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene(l) for detecting Zn2+ in aqueous medium was synthesized. L–Zn2+ complex, showed selectivity toward pyrophosphate ion (PPi) by quenching the fluorescence in aqueous HEPES buffer (pH 7.4). Furthermore, L–Zn2+ was also used to set up a real-time fluorescence assay for monitoring enzyme activities of alkaline phosphatase (ALP) and adenosine triphosphate sulfurylase (ATPS). In the presence of ALP inhibitor Na3VO4 and ATPS inhibitor chlorate, two enzymes activities decreased obviously, respectively.We established a real-time fluorescence assay of ATP sulfurylase activity by employing PPi as substrate. Furthermore, our fluorescence system can be used to screen potentially eligible ATP sulfurylase inhibitors.

Cubic phase NH4Eu3F10 nanospheres with controllable sizes were synthesized via a modified hydrothermal route by varying the dosage of ammonium hydroxide solution. Dependence of structure and morphology on the dosage of ammonia water and reaction time were investigated by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). Being unstable, NH4Eu3F10 decomposed into EuF3 and NH4F during the long-time hydrothermal treatment. EDTA, as the chelation agent of Eu3+ and the capping ligand on the surface of as-obtained nanospheres, showed different chelating abilities depending on the dosage of ammonium hydroxide solution. Increasing the amount of ammonia not only decreased the effective concentration of Eu3+, but also decelerated the growth of NH4Eu3F10 nanospheres and stabilized them by reducing the surface energy. Given the satisfactory hydrophilicity, biocompatibility, and luminescence, the as-obtained nanospheres were applied as promising agents for cell imaging by presenting high contrast.

A Tb(III) complex of THP [1,4,7,10-tetrakis(2-hydroxypropyl)-cyclen] (THPTb) cleaved RNA phosphate ester bonds at A-specific sites to mimic RNase U2. The intermediates of the adducts of THPTb2+ and CPP− (cyclic propylene phosphate) or HPNP− (2-hydroxy propyl-p-nitrophenylphosphate) in the hydrolysis of HPNP were directly monitored by electrospray ionization mass spectrometry (ESI-MS).

An NBD-armed tetraaza macrocyclic lysosomal-targeted fluorescent probe for detecting Cu2+ was synthesized and used for fluorescence imaging in HeLa cells. The probe was specifically localized in lysosomes and successfully applied to visualize Cu2+ as well as to monitor Cu2+ level changes in the lysosomes of living cells.

Prolyl hydroxylase 3 (PHD3) controls hypoxia-inducible factor-1 (HIF-1) degradation by oxygen dependent hydroxylation. PHD3 inhibitors are potential targets for HIF-1α activation, thereby treating a number of HIF-related diseases. We herein rationally designed a novel scaffold for PHD3 inactivation under the guidance of enzyme–ligand docking simulation studies. The potent inhibitors were able to non-covalently bind to the active site of PHD3, and to stabilize the core domain resisting to trypsin proteolysis. The conformational changes of the protein occurred concomitant with inhibitor binding, which thus deactivated the enzyme. The up-regulated levels of HIF-1α protein and downstream genes (glucose transporter-1 (GLUT-1) and vascular endothelial growth factor (VEGF)) suggest that the PHD inhibitors manage to mimic the cellular signalling effects of hypoxia. Interestingly, unlike available PHD inhibitors, the iron-chelating motif is not found in all azole compounds, among which we identified a unique compound 1-(2-(1H-benzo[d]imidazol-2-yl)ethyl)-1H-benzo[d][1,2,3]triazole (BEBT) as the most effective inhibitor. BEBT binds to the enzyme with the lowest predicted binding energy, and activates HIF activity most significantly in cellular systems. This novel non-iron-chelating inhibitor offers a new target for the drug design towards hypoxia-related diseases therapy with possibly minimized iron-relating side effects.

•hAS3MT mutants D76P, D76N, D84P, D84N, D102P, D102N, D150P and D150N were designed.•All mutants except for D150N were inactive.•Asp76, 84, 102 and 150 of hAS3MT greatly affected hAS3MT catalytic activity.•Asp102 plays a dominant role in SAM-binding via forming hydrogen bonds with SAM.We prepared eight mutants (D76P, D76N, D84P, D84N, D102P, D102N, D150P and D150N) to investigate the functions of residues Asp76, 84, 102 and 150 in human arsenic(III) methyltransferase (hAS3MT) interacting with the S-adenosylmethionine (SAM)-binding. The affinity of all the mutants for SAM were weakened. All the mutants except for D150N completely lost their methylation activities. Residues Asp76, 84, 102 and 150 greatly influenced hAS3MT catalytic activity via affecting SAM-binding or methyl transfer. Asp76 and 84 were located in the SAM-binding pocket, and Asp102 significantly affected SAM-binding via forming hydrogen bonds with SAM.

An NBD-armed tetraaza macrocyclic lysosomal-targeted fluorescent probe for detecting Cu2+ was synthesized and used for fluorescence imaging in HeLa cells. The probe was specifically localized in lysosomes and successfully applied to visualize Cu2+ as well as to monitor Cu2+ level changes in the lysosomes of living cells.