A two-photon excited near-infrared fluorescent probe for imaging peroxynitrite during drug-induced hepatotoxicity and its remediation.

Drug-induced liver injury (DILI) has been a hot issue of public health, owing to its unpredictability and serious harm to public health. Peroxynitrite (ONOO-) is an important biomarker for the assessment and diagnosis of DILI. In this article, based on a kind of rhodamine analogue with a near-infrared (NIR) emission (610 nm-800 nm) and a two-photon absorption cross section (54 GM), a two-photon excited NIR fluorescence probe (NIR-ONOO) for ONOO- was developed. With a high selectivity and a high sensitivity to ONOO-, NIR-ONOO has a linear range for detection of ONOO- from 5.0 × 10-8 to 1.0 × 10-5 M, a good detection limit (15 nM) and a large fluorescence enhancement (340-fold). In addition, NIR-ONOO has been used to monitor ONOO- in cells with satisfactory results. Because of its two-photon excied NIR emission, NIR-ONOO also showed excellent performances for imaging ONOO- including low autofluorescence, stable and persistent fluorescence, and a deep penetration (204 µm). Finally, NIR-ONOO was successfully employed to image ONOO- in inflammatory mouse, drug-induced hepatotoxicity in cells and its remediation. All the results indicated that NIR-ONOO is a powerful chemical tool to image ONOO- and assay drug-induced hepatotoxicity.

A photostable Si-rhodamine-based near-infrared fluorescent probe for monitoring lysosomal pH during heat stroke.

Heat stroke is a symptom of hyperthermia with a temperature of more than 40 °C, which usually leads to all kinds of physical discomfort and even death. It is necessary to study the mechanism of action of heat stroke on cells or organelles (such as cytotoxicity of heat) and the processes of cells or organelles during heat stroke. Recent studies have shown that there is a certain correlation between heat stroke and lysosome acidity. In order to clarify their relationship, Lyso-NIR-pH, a photostable Si-rhodamine-based near-infrared fluorescent probe, was developed for sensing pH changes in lysosomes during heat stroke in this paper. For Lyso-NIR-pH, a morpholine group is employed as the lysosome-targeting unit and a H+-triggered openable deoxylactam is employed as the response unit to pH. Lyso-NIR-pH can detect pH with a high selectivity and a sensitivity, and its pKa is 4.63. Lyso-NIR-pH also has outstanding imaging performances, such as excellent lysosome-targeting ability, low autofluorescence and photostable fluorescence signal, which are in favor of long-term imaging of pH with accurate fluorescence signals. Moreover, we successfully applied Lyso-NIR-pH to monitor lysosomal pH increases induced by chloroquine and apoptosis in live cells. Finally, we successfully applied Lyso-NIR-pH for monitoring changes of lysosomal pH during heat stroke. These results confirmed that Lyso-NIR-pH is a powerful tool to monitor pH change in lysosomes and study its possible effects.

A mitochondria-targetable two-photon fluorescent probe with a far-red to near-infrared emission for sensing hypochlorite in biosystems.

Hypochlorite (ClO-), one of reactive oxygen species (ROS), is closely related with many physiological and pathological processes. Especially as one of cellular reactive oxygen species in mitochondria, ClO- can induce mitochondrial permeability, which leads to apoptosis. Thus, developing an effective method which is able to sense ClO- in mitochondria is important. Although fluorescent probe has become a powerful tool for imaging ClO- in mitochondria, most of them suffered from phototoxicity to biosamples, autofluorescence, and photobleaching phenomenon due to their short-wavelength excitations and emissions. Based on advantages of two-photon fluorescent probe and far-red to NIR fluorescent probe, a mitochondria-targetable two-photon fluorescent probe with a turn-on signal in far-red to NIR region, Mito-TP-ClO, was developed for ClO- in this paper. Mito-TP-ClO is consisted of a triphenylphosphonium cations as a mitochondria-targetable unit and a structure of dibenzoylhydrazine as a response unit to ClO-. Mito-TP-ClO exhibited a high sensitivity and a high selectivity to ClO-, with a linear range from 6.0 × 10-8 to 1.0 × 10-5 M and a detection limit of 2.5 × 10-8 M. Due to its large two-photon cross section (267 GM) and far-red to NIR emission, Mito-TP-ClO exhibits excellent performances including low autofluorescence, photostable fluorescence signal, and deep tissue penetration (230 µM). Moreover, Mito-TP-ClO was successfully used to detect endogenous ClO- in bacteria-infected cells and inflammatory mouse model, which confirmed that Mito-TP-ClO is a powerful tool to monitor ClO- in mitochondria and study on effects of hypochlorite on mitochondria.

The Maternal Effect Genes UTX and JMJD3 Play Contrasting Roles in Mus musculus Preimplantation Embryo Development.

During the process of embryonic development in mammals, epigenetic modifications must be erased and reconstructed. In particular, the trimethylation of histone 3 lysine 27 (H3K27me3) is associated with gene-specific transcriptional repression and contributes to the maintenance of the pluripotent embryos. In this study, we determined that the global levels of the H3K27me3 marker were elevated in MII oocyte chromatin and decrease to minimal levels at the 8-cell and morula stages. When the blastocyst hatched, H3K27me3 was re-established in the inner cell mass. We also determined that H3K27me3-specific demethylases, UTX and JMJD3, were observed at high transcript and protein levels in mouse preimplantation embryos. In the activated oocytes, when the H3K27me3 disappeared at the 8-cell stage, the UTX (but not JMJD3) protein levels were undetectable. Using RNA interference, we suppressed UTX and JMJD3 gene expression in the embryos and determined that the functions of UTX and JMJD3 were complementary. When JMJD3 levels were decreased by RNA interference, the embryo development rate and quality were improved, but the knockdown of UTX produced the opposite results. Understanding the epigenetic mechanisms controlling preimplantation development is critical to comprehending the basis of embryonic development and to devise methods and approaches to treat infertility.

Expression levels of GSTA2 and APOD genes might be associated with carotenoid coloration in golden pheasant (Chrysolophus pictus) plumage.

Carotenoids, which generate yellow, orange, and red colors, are crucial pigments in avian plumage. Investigations into genes associated with carotenoidbased coloration in avian species are important; however, such research is difficult because carotenoids cannot be synthetized in vertebrates as they are only derived from dietary sources. Here, the golden pheasant (Chrysolophus pictus) was used as a model in analysis of candidate gene expression profiles implicated in carotenoid binding and deposition. Using mass and Raman spectrometry to confirm the presence of carotenoids in golden pheasant feathers, we found C40H54O and C40H56O2 in feathers with yellow to red colors, and in the rachis of iridescent feathers. The global gene expression profiles in golden pheasant skins were analyzed by RNA-seq and all six carotenoid binding candidate genes sequenced were studied by realtime PCR. StAR4, GSTA2, Scarb1, and APOD in feather follicles showed different expressions in red breast and orange nape feathers compared with that of iridescent mantle feathers. Further comparison of golden pheasant yellow rump and Lady Amherst's pheasant (Chrysolophus amherstiae) white nape feathers suggested that GSTA2 and APOD played a potential role in carotenoid-based coloration in golden pheasant.