A natural product phillygenin suppresses osteosarcoma growth and metastasis by regulating the SHP-1/JAK2/STAT3 signaling.

Osteosarcoma represents one of the most devastating cancers due to its high metastatic potency and fatality. Osteosarcoma is insensitive to traditional chemotherapy. Identification of a small molecule that blocks osteosarcoma progression has been a challenge in drug development. Phillygenin, a plant-derived tetrahydrofurofuran lignin, has shown to suppress cancer cell growth and inflammatory response. However, how phillygenin plays functional roles in osteosarcoma has remained unveiled. In this study, we showed that phillygenin inhibited osteosarcoma cell growth and motility in vitro. Further mechanistic studies indicated that phillygenin blocked STAT3 signaling pathway. Phillygenin led to significant downregulation of Janus kinase 2 and upregulation of Src homology region 2 domain-containing phosphatase 1. Gene products of STAT3 regulating cell survival and invasion were also inhibited by phillygenin. Therefore, our studies provided the first evidence that phillygenin repressed osteosarcoma progression by interfering STAT3 signaling pathway. Phillygenin is a potential candidate in osteosarcoma therapy.

mRNA-Initiated, Three-Dimensional DNA Amplifier Able to Function inside Living Cells.

DNA molecular machines show great promise in fields such as biomarker discovery and biological activity regulation, but operating DNA machines with specific functions within living systems remains extremely challenging. Although DNA machines have been engineered with exact molecular-level specifications, some intrinsic imperfections such as poor cell permeation and fragility in complex cytoplasmic milieu persist due to the well-established character of nucleic acid molecules. To circumvent these problems, we herein report a molecularly engineered, entropy-driven three-dimensional DNA amplifier (EDTD) that can operate inside living cells in response to a specific mRNA target. In particular, mRNA target/EDTD interaction can specifically initiate an autonomous DNA circuit inside living cells owing to the exclusive entropy-driven force, thus providing enormous signal amplification for ultrasensitive detection of the mRNA. Moreover, owing to molecular engineering of a unique DNA tetrahedral framework into the DNA amplifier, EDTD exhibits significantly enhanced biostability and cellular uptake efficiency, which are prerequisites for DNA machines used for in vivo applications. This programmable DNA machine presents a simple and modular amplification mechanism for the detection of intracellular biomarkers. Moreover, this study provides a potentially valuable molecular tool for understanding the chemistry of cellular systems and offers a design blueprint for further expansion of DNA nanotechnology in living systems.

Localizable and photoactivatable fluorophore for spatiotemporal two-photon bioimaging.

Photoactivatable probe-based fluorescent imaging has become an efficient and attractive technique for spatiotemporal microscopic studies of biological events. However, almost all previously reported photoactivatable organic probes have been based on hydrosoluble precursors, which have produced water-soluble active fluorophores able to readily diffuse away from the photocleavage site, thereby dramatically reducing spatial resolution. Hydroxyphenylquinazolinone (HPQ), a small organic dye known for its classic luminescence mechanism through excited-state intramolecular proton transfer (ESIPT), shows strong light emission in the solid state, but no emission in solution. In this work, HPQ was employed as a precursor to develop a localizable, photoactivatable two-photon probe (PHPQ) for spatiotemporal bioimaging applications. After photocleavage, PHPQ releases a precipitating HPQ fluorophore which shows both one-photon and two-photon excited yellow-green fluorescence, thereby producing a localizable fluorescence signal that affords high spatial resolution for bioimaging, with more than 200-fold one-photon and 150-fold two-photon fluorescence enhancement.

An efficient ratiometric fluorescent probe for tracking dynamic changes in lysosomal pH.

Lysosomes are acidic organelles (approximately pH 4.5-5.5) and tracking the changes in lysosomal pH is of great biological importance. To address this issue, quite a few of fluorescent probes have been developed. However, few of these probes can realize the tracking of dynamic changes in lysosomal pH. Herein, we report a new lysosome-targeted ratiometric fluorescent probe (FR-Lys) by hybridizing morpholine with a xanthane derivative and an o-hydroxy benzoxazole group. In this probe, the morpholine group serves as a targeting unit for lysosome, the xanthane derivative exhibits a pH-modulated open/close reaction of the spirocycle, while the o-hydroxy benzoxazole moiety shows a pH modulated excited-state intramolecular proton transfer (ESIPT) process. Such a design affords the probe a ratiometric fluorescence response towards pH with pH values ranging from 4.0 to 6.3. The response of the probe to pH was fast and reversible with high selectivity. Moreover, this probe possesses further advantages such as easy synthesis, high photostability and low cytotoxicity. These features are favorable for tracking dynamic pH changes in biosystems. It was then applied for dynamic imaging pH changes in lysosomes with satisfactory results.

Preparation of amino-modified carbon quantum dots-ZnO/cellulose nanofiber multifunctional hydrogel: Enhanced adsorption synergistic photoreduction and reversible fluorescence response visual recognition of Cr(VI).

This work innovatively used cellulose nanofibers as a photocatalyst carrier, which could recycle nano-photocatalysts and minimize nanoparticle aggregation. The morphology, structures, chemical composition, optical-electronic properties and photocatalytic performance of amino-modified carbon quantum dots-ZnO/cellulose nanofiber (N-CQDs-ZnO/CNF: ZCH-2) hydrogel were characterized by SEM, TEM, BET, EDS, XRD, FTIR, UV-vis, XPS, PL and other techniques. The mechanism of Cr(VI) adsorption synergistic photoreduction by ZCH-2 was discussed in detail. The results showed that the prepared ZCH-2 had excellent removal performance for Cr(VI). After 120 min of adsorption and 40 min of photoreduction, the removal efficiency of Cr(VI) was 98.9 %. Compared with ZnO/CNF hydrogel, the adsorption performance of ZCH-2 increased by 268 % and the photoreduction performance increased by 116 %. The adsorption of Cr(VI) by ZCH-2 was controlled by electrostatic attraction and chemical adsorption. The photoreduction kinetic constant of ZCH-2 was 0.106 min-1, which was 8.9 times that of ZnO/CNF hydrogel. The N-CQDs in ZCH-2 could form N-CQDs-metal complexes with Cr(VI), resulting in fluorescence quenching, so Cr(VI) could be visually identified by fluorescence changes. This study provides a new idea for the design and optimization of a new multifunctional hydrogel with efficient adsorption-photoreduction-fluorescence recognition.

High-sensitivity naphthalene-based two-photon fluorescent probe suitable for direct bioimaging of H2S in living cells.

H2S is the third endogenously generated gaseous signaling compound and has also been known to involve a variety of physiological processes. To better understand its physiological and pathological functions, efficient methods for monitoring of H2S in living systems are desired. Although quite a few one photon fluorescence probes have been reported for H2S, two-photon (TP) probes are more favorable for intracellular imaging. In this work, by employing a donor-π-acceptor-structured naphthalene derivative as the two-photon fluorophore and an azide group as the recognition unit, we reported a new two-photon bioimaging probe 6-(benzo[d]thiazol-2'-yl)-2-azidonaphthalene (NHS1) for H2S with improved sensitivity. The probe shows very low background fluorescence in the absence of H2S. In the presence of H2S, however, a significant enhancement for both one photon and TP excited fluorescence were observed, resulting in a high sensitivity to H2S in aqueous solutions with a detection limit of 20 nM observed, much lower than the previously reported TP probe. The probe also exhibits a wide linear response concentration range (0-5 µM) to H2S with high selectivity. All these features are favorable for direct monitoring of H2S in complex biological samples. It was then applied for direct TP imaging of H2S in living cells with satisfactory sensitivity, demonstrating its value of practical application in biological systems.

CALB1: Anovel antiviral factor in chicken ileal mucus.

Intestinal mucus is the first line of defense against pathogens and has several active components. Poultry have a short intestine, the mucus of which may contain antiviral components. We hence investigated the antiviral components of mucus and explored their mechanisms of action. Initially, we isolated chicken intestinal mucus proteins that significantly inhibited the replication of avian viruses. The ileum 10-30 kDa protein fraction showed the greatest inhibition of viral replication. Moreover, liquid chromatography-mass spectrometry revealed 12 high-abundance proteins in the ileum 10-30 kDa protein fraction. Among them, we investigated the antiviral activity of calcium binding protein 1 (CALB1). Furthermore, eukaryotically and prokaryotically expressed CALB1 significantly suppressed the replication of avian viruses, possibly by binding calcium ions and/or inducing autophagy. In conclusion, we isolated and identified CALB1 from chicken intestinal mucus, which suppressed replication of avian viruses by regulating cellular calcium-ion homeostasis and autophagy.

IBV QX affects the antigen presentation function of BMDCs through nonstructural protein16.

The gamma-coronavirus infectious bronchitis virus (IBV) has a high mutation rate and mainly invades the respiratory mucosa, making it difficult to prevent and causing great economic losses. Nonstructural protein 16 (NSP16) of IBV QX also not only plays an indispensable role in virus invading but also might hugely influence the antigen's recognition and presentation ability of host BMDCs. Hence, our study tries to illustrate the underline mechanism of how NSP16 influences the immune function of BMDCs. Initially, we found that NSP16 of the QX strain significantly inhibited the antigen presentation ability and immune response of mouse BMDCs, which was stimulated by Poly (I:C) or AIV RNA. Besides mouse BMDCs, we also found that NSP16 of the QX strain also significantly stimulated the chicken BMDCs to activate the interferon signaling pathway. Furthermore, we preliminarily demonstrated that IBV QX NSP16 inhibits the antiviral system by affecting the antigen-presenting function of BMDCs.

Study on the Influencing Factors of Osteoarthritis in Southern China.

Background: Osteoarthritis (OA) is a common chronic disease with numerous and interacting influencing factors, and current inadequate patient perceptions and behaviors in access to care contribute to the difficulties in the diagnosis, treatment, and management of osteoarthritis. Objective: The purpose of this study was to investigate the influencing factors of osteoarthritis (OA) in a southern Chinese population and to provide a scientific basis for the prevention and treatment of OA. Methods: A 1 : 2 matched case-control study was used to select 160 patients with OA from three hospitals in southern China as a case group. Three hundred and twenty cases of the same sex and similar age (within ± 2 years) were selected as the control group, and relevant data were collected for univariate and multivariate conditional logistic regression analysis. Results: There were no significant differences between the two groups of participants in terms of age, sex, and education (P > 0.05). Logistic regression statistical analysis showed that genetic factors (OR = 4.52, 95% CI = 1.56-7.83), body mass index (OR = 2.57, 95% CI = 1.16-5.84), alcohol consumption (OR = 3.81, 95% CI = 1.53-5.87), and a history of external joint limb injury (OR = 3.37, 95% CI = 1.67-5.24) would increase the risk of OA. In contrast, eating more fresh vegetables (OR = 0.08, 95% CI = 0.03-0.31), more fresh fruits (OR = 0.34, 95% CI = 0.12-0.96), more soy products (OR = 0.11, 95% CI = 0.04-0.45), and exposure to sunlight (OR = 0.31, 95% CI = 0.14-0.71) would reduce the OA risk of OA. Conclusion: Obesity, alcohol consumption, and a history of joint trauma all increase the risk of OA in a southern Chinese population, whereas a diet rich in fresh vegetables, fresh fruit, soy products, and sun exposure would reduce the risk of OA. In the future, we should focus on improving patients' awareness of medical care and developing their self-management skills, improving GPs' treatment skills, improving negative attitudes of both doctors and patients, and promoting positive patient care.

Selective Recognition of Gallic Acid Using Hollow Magnetic Molecularly Imprinted Polymers with Double Imprinting Surfaces.

Gallic acid is widely used in the field of food and medicine due to its diversified bioactivities. The extraction method with higher specificity and efficiency is the key to separate and purify gallic acid from complex biological matrix. Herein, using self-made core-shell magnetic molecularly imprinted polymers (MMIP) with gallic acid as template, a hollow magnetic molecularly imprinted polymer (HMMIP) with double imprinting/adsorption surfaces was prepared by etching the mesoporous silica intermediate layer of MMIP. The characterization and adsorption research showed that the HMMIP had larger specific surface area, higher magnetic response strength and a more stable structure, and the selectivity and saturated adsorption capacity (2.815 mmol/g at 318 K) of gallic acid on HMMIP were better than those of MMIP. Thus, in addition to MMIP, the improved HMMIP had excellent separation and purification ability to selectively extract gallic acid from complex matrix with higher specificity and efficiency.

Molecular beacon-based junction probes for efficient detection of nucleic acids via a true target-triggered enzymatic recycling amplification.

This work reports the development of a new molecular beacon-based junction sensing system with highly sensitive DNA detection and a strong capability to identify SNPs. The single linear probe typically labels the midsection of the oligonucleotide, but our next-generation junction sensing system uses a hairpin-structured MB with labels on each end of the oligonucleotide to maintain the cleaving activity of our newly designed ssDNA-cleaved endonuclease, Nt.BbvCI, rather than the typical dsDNA-cleaved endonuclease. These design improvements guarantee a true and efficient target-triggered enzymatic recycling amplification process in our sensing system. They also afford a faster and more sensitive response toward target DNA than the first-generation junction sensing system.

Fluorescent probe for the detection of hypochlorous acid in water samples and cell models.

Hypochlorous acid (HClO) is a special kind of reactive oxygen species, which plays an important role in resisting pathogen invasion and maintaining cell redox balance and other physiological processes. In addition, HClO is commonly used in daily life as a bleaching and disinfectant agent. Its excessive use can also lead to death of water animals and serious respiratory and skin diseases in humans. Therefore, it is of great significance to develop a quick and convenient tool for detecting HClO in the environment and organisms. In this paper, we utilize the specific reaction of HClO with dimethylthiocarbamate to develop a novel naphthalene derivative fluorescent probe (BNA-HClO), it was designed and synthesized by using 6-(2-benzothiazolyl)-2-naphthol as the fluorophore and N,N-dimethylthiocarbamate as the recognition group. BNA-HClO shows large fluorescence enhancement (374-fold), high sensitivity (a detection limit of 37.56 nM), rapid response (<30 s), strong anti-interference ability and good specificity in vitro. Based on the outstanding in vitro sensing capability of BNA-HClO, it has been successfully used to detect spiked HClO in tap water, medical wastewater and fetal bovine serum with good recovery. BNA-HClO has also been successfully used as a portable test strip for the in situ semi-quantitative detection of HClO in tap water solutions. In addition, BNA-HClO can successfully enable the detection and imaging of exogenous and endogenous HClO in living cells. This work provides a simple and effective tool for the detection and imaging of HClO in environmental and biological systems, and provides some theoretical guidance for future exploration of biological and pathological studies related to HClO.

A two-photon "turn-on" fluorescent probe for both exogenous and endogenous selenocysteine detection and imaging in living cells and zebrafish.

Selenocysteine (Sec) is recognized as the 21st amino acid employing as an essential building block for selenoproteins (SePs), which plays a significant role in various physiological processes. Therefore, there is an urgent need to reasonably develop some reliable and rapid methods for Sec detection in biological systems. In this work, we reported a new two-photon (TP) fluorescent probe BNT-Sec for Sec detection and imaging in living cells and zebrafish with two part: (1) a D-π-A-structured naphthalene derivative as a TP fluorophore; (2) a well-know Sec responsive site with strong intromolecular charge transfer effect (ICT) to selectively detect endogenous and exogenous. In the presence of Sec, probe BNT-Sec can initiate a Se-dependent specific aromatic nucleophilic substitution reaction, which exhibited BNT-Sec had a large fluorescence intensity enhancement with ~18.9-fold at 510 nm, a high sensitivity low LOD value' 10.6 nM, good light stability, strong specificity, pH stability and low cytotoxicity. In addition, BNT-Sec can be conveniently used to detect Sec in living cells and zebrafish for TP imaging due to the great TP measurement properties of fluorophore, exhibiting it has the potential to reveal the role of selenocysteine in physiological and pathological processes in further biological applications.

Enhancement of long-lived luminescence in nanophosphors by surface defect passivation.

Herein, we found that surface defects quench persistent luminescence in nanophosphors. Passivation of surface defects by thermal treatment or surface coating can effectively enhance the intensity and prolong the decay time of persistent luminescence. The surface passivated persistent nanophosphors are promising in autofluorescence-free bioimaging and time-gated steganography.

Vinyl Phosphate-Functionalized, Magnetic, Molecularly-Imprinted Polymeric Microspheres' Enrichment and Carbon Dots' Fluorescence-Detection of Organophosphorus Pesticide Residues.

The rapid detection of organophosphorus pesticide residues in food is crucial to food safety. One type of novel, magnetic, molecularly-imprinted polymeric microsphere (MMIP) was prepared with vinyl phosphate and 1-octadecene as a collection of dual functional monomers, which were screened by Gaussian09W molecular simulation. MMIPs were used to enrich organic phosphorus, which then detected by fluorescence quenching in vinyl phosphate-modified carbon dots (CDs@VPA) originated from anhydrous citric acid. MMIPs and CDs@VPA were characterized by TEM, particle size analysis, FT-IR, VSM, XPS, adsorption experiments, and fluorescence spectrophotometry in turn. Through the fitting data from experiment and Gaussian quantum chemical calculations, the molecular recognition properties and the mechanism of fluorescence detection between organophosphorus pesticides and CDs@VPA were also investigated. The results indicated that the MMIPs could specifically recognize and enrich triazophos with the saturated adsorption capacity 0.226 mmol g-1, the imprinting factor 4.59, and the limit of recognition as low as 0.0006 mmol L-1. Under optimal conditions, the CDs@VPA sensor has shown an extensive fluorescence property with a LOD of 0.0015 mmol L-1 and the linear range from 0.0035 mmol L-1 to 0.20 mmol L-1 (R2 = 0.9988) at 390 nm. The mechanism of fluorescence detection of organic phosphorus with CDs@VPA sensor might be attributable to hydrogen bonds formed between heteroatom O, N, S, or P, and the O-H group, which led to fluorescent quenching. Meanwhile, HN-C=O and Si-O groups in CDs@VPA system might contribute to cause excellent blue photoluminescence. The fluorescence sensor was thorough successfully employed to the detection of triazophos in cucumber samples, illustrating its tremendous value towards food sample analysis in complex matrix.

A label-free and sensitive photoluminescence sensing platform based on long persistent luminescence nanoparticles for the determination of antibiotics and 2,4,6-trinitrophenol.

The rapid detection of pollutants with high sensitivity and selectivity is of considerable significance for security screening, environmental safety, and human health. In this study, we prepared persistent luminescence nanoparticles (PLNPs) and constructed a label-free sensor for sensitive and selective detection of pollutants in real samples and test papers. Following excitation, PLNPs could store absorbed light energy and release it in the form of luminescence. Compared with a fluorescence-based technique, a PLNPs-based measurement could effectively avoid background interference. Under optimal conditions, the limit of detection for TNP was found to be 10 nM, while for an antibiotic it was 5 nM. The nanoprobe was successfully applied for the detection of pollutants in real samples including milk and Dianchi Lake water samples. Due to the long-lasting afterglow nature of PLNPs, the signal-to-noise ratio could be greatly increased in complex real samples. By hand-writing with TNP solution as ink on filter paper, the photoluminescence (PL) of the part stained with TNP was immediately quenched. Moreover, after direct exposure under a UV lamp for 10 min and without further excitation, the luminescence of the test paper was investigated to avoid interferents. This PLNP material could be potentially employed as a multi-responsive luminescent sensor. In addition, these easy-to-use visual techniques could provide a powerful tool for a convenient POC assay of organic pollutants.

Molecular engineering of a mitochondrial-targeting two-photon in and near-infrared out fluorescent probe for gaseous signal molecules H2S in deep tissue bioimaging.

Hydrogen sulfide (H2S), one of the biologically important gaseous signal molecules, plays an essential role in diverse normal biochemical functions and pathological processes. Herein, an efficient two-photon in and near-infrared out mitochondria-targeting dye has been designed, synthesized and characterized. It is easily synthesized by the condensation reaction (CË­C) of 4-hydroxybenzaldehyde and 6-(diethylamino)-1,2,3,4-tetrahydroxanthylium (mitochondria-targeting), which possesses large two-photon action absorption cross-section ~160g and high fluorescence quantum yield ~0.15. Encouraged by the results, we proceeded to conjugate this new dye with a H2S recognition moiety (4-dinitrobenzene-ether, DNB), on the basis of the intramolecular charge transfer (ICT) strategy, to construct a novel H2S fluorescent probe (TP-NIR-HS), which shows a targeting ability with high sensitivity and selectivity, and low cytotoxicity. This new probe was then applied for two-photon imaging of living cells and tissues and showed high imaging resolution and a deep-tissue imaging depth of ~350µm, thus demonstrating its practical application in biological systems, and providing a valuable theoretical basis and technical support for the study of physiological and pathological functions of H2S.

Tetraphenylethene derivative modified DNA oligonucleotide for in situ potassium ion detection and imaging in living cells.

The monitoring of K+ is very important and emergency because of their unique relationship in various disease diagnosis and treatment. G-quadruplex analogue is a classical recognition unit for K+ detection and has been widely applied in K+ relevant research. Common fluorescent dyes were employed for design of G-quadruplex structure-based K+ probes which suffered from the aggregation-caused quenching effect, and possibly limited the biological applications in living systems. Herein, we report an aggregation-induced emission (AIE) effect-based fluorescent probe for cellular K+ analysis and imaging. Benefitting from the K+ triggered AIE phenomenon, the designed TPE derivative modified guanine (G)-rich oligonucleotide fluorescent probe (TPE-oligonucleotide probe) exhibits high sensitivity (∼10-fold higher than most reported G-quadruplex-based probes) with extended photostability which facilitates the prolonged fluorescence observations of K+ in living cells. On the basis of these advantages, the TPE-oligonucleotide probe serves as a promising candidate for the functional study and analysis of K+.

A universal aptameric biosensor: Multiplexed detection of small analytes via aggregated perylene-based broad-spectrum quencher.

A universal aptameric system based on the taking advantage of double-stranded DNA/perylene diimide (dsDNA/PDI) as the signal probe was developed for multiplexed detection of small molecules. Aptamers are single-stranded DNA or RNA oligonucleotides which are selected in vitro by a process known as systematic evolution of ligands by exponential enrichment. In this work, we synthesized a new kind of PDI and reported this aggregated PDI could quench the double-stranded DNA (dsDNA)-labeled fluorophores with a high quenching efficiency. The quenching efficiencies on the fluorescence of FAM, TAMRA and Cy5 could reach to 98.3%±0.9%, 97.2%±0.6% and 98.1%±1.1%, respectively. This broad-spectrum quencher was then adopted to construct a multicolor biosensor via a label-free approach. A structure-switching-triggered enzymatic recycling amplification was employed for signal amplification. High quenching efficiency combined with autocatalytic target recycling amplification afforded the biosensor with high sensitivity towards small analytes. For other targets, changing the corresponding aptamer can achieve the goal. The quencher did not interfere with the catalytic activity of nuclease. The biosensor could be manipulated with similar sensitivity no matter in pre-addition or post-addition manner. Moreover, simultaneous and multiplexed analysis of several small molecules in homogeneous solution was achieved, demonstrating its potential application in the rapid screening of multiple biotargets.