Synthesis and Broad Antiviral Activity of Novel 2-aryl-isoindolin-1-ones towards Diverse Enterovirus A71 Clinical Isolates.

Enterovirus 71 (EV-A71) is the main causative pathogen of childhood hand, foot and mouth disease. Effective medicine is currently unavailable for the treatment of this viral disease. Using the fragment-hopping strategy, a series of 2-aryl-isoindolin-1-one compounds were designed, synthesized and investigated for their in vitro antiviral activity towards multiple EV-A71 clinical isolates (H, BrCr, Shenzhen98, Jiangsu52) in Vero cell culture in this study. The structure⁻activity relationship (SAR) studies identified 2-phenyl-isoindolin-1-ones as a new potent chemotype with potent antiviral activity against EV-A71. Ten out of the 24 tested compounds showed significant antiviral activity (EC50 < 10 µM) towards four EV-A71 strains. Compounds A3 and A4 exhibited broad and potent antiviral activity with the 50% effective concentration (EC50) values in the range of 1.23⁻1.76 µM. Moreover, the selectivity indices of A3 and A4 were significantly higher than those of the reference compound, pirodavir. The western blotting experiment indicated that the viral VP1 was significantly decreased at both the protein and RNA level in a dose-dependent manner following treatment with compound A3. Moreover, compound A3 inhibited the viral replication by acting on the virus entry stage. In summary, this study led to the discovery of 2-aryl-isoindolin-1-ones as a promising scaffold with potent anti-EV-A71 activities, which deserves further in-depth studies.

Tribbles pseudokinase 3 promotes enterovirus A71 infection via dual mechanisms.

Enterovirus A71 (EV-A71) is the main pathogen causing hand, foot and mouth disease (HFMD) in children and occasionally associated with neurological diseases such as aseptic meningitis, brainstem encephalitis (BE) and acute flaccid paralysis. We report here that cellular pseudokinase tribbles 3 (TRIB3) facilitates the infection of EV-A71 via dual mechanisms. In one hand, TRIB3 maintains the metabolic stability of scavenger receptor class B member 2 (SCARB2), the bona fide receptor of EV-A71, to enhance the infectious entry and spreading of the virus. On the other hand, TRIB3 facilitates the replication of EV-A71 RNA in a SCARB2-independent manner. The critical role of TRIB3 in EV-A71 infection and pathogenesis was further demonstrated in vivo in mice. In comparison to wild-type C57BL/6 mice, EV-A71 infection in TRIB3 knockdown mice (Trib3+/-) resulted in significantly lower viral loads in muscular tissues and reduced lethality and severity of clinical scores and tissue pathology. In addition, TRIB3 also promoted the replication of coxsackievirus B3 (CVB3) and coxsackievirus A16 (CVA16) in vitro. In conclusion, our results suggest that TRIB3 is one of key host cellular proteins required for the infection and pathogenesis of EV-A71 and some other human enteroviruses and may thus be a potential therapeutic target for combating the infection of those viruses.

The antiviral effect of 7-hydroxyisoflavone against Enterovirus 71 in vitro.

Enterovirus 71 (EV71) is the major causative agent of hand foot and mouth disease. And EV71 causes epidemics worldwide, particularly in the Asia-Pacific region. Unfortunately, currently there is no approved vaccine or antiviral drug for EV71-induced disease prevention and therapy. In screening for anti-EV71 candidates, we found that 7-hydroxyisoflavone was active against EV71. 7-Hydroxyisoflavone exhibited strong antiviral activity against three different EV71 strains. The 50% inhibitory concentration range was between 3.25 and 4.92 µM by cytopathic effect assay. 7-Hydroxyisoflavone could reduce EV71 viral RNA and protein synthesis in a dose-dependent manner. Time course study showed that treatment of Vero cells with 7-hydroxyisoflavone at indicated times after EV71 inoculation (0-6 h) resulted in significant antiviral activity. Results showed that 7-hydroxyisoflavone acted at an early step of EV71 replication. 7-Hydroxyisoflavone also exhibited strong antiviral activity against coxsackievirus B2, B3, and B6. In short, 7-hydroxyisoflavone may be used as a lead compound for anti-EV71 drug development.

Evaluation and mechanism study of Pien Tze Huang against EV-A71 infection.

Hand, foot, and mouth disease (HFMD) caused by enterovirus A71 (EV-A71) infection, currently lacks specific preventive and therapeutic interventions. Here, we demonstrated that Pien Tze Huang (PZH) could dose-dependently inhibit EV-A71 replication at the cellular level, resulting in significant reductions in EV-A71 virus protein 1 (VP1) expression and viral yields in Vero and human rhabdomyosarcoma cells. More importantly, we confirmed that PZH could protect mice from EV-A71 infection for the first time, with Ribavirin serving as a positive control. PZH treatment reduced EV-A71 VP1 protein expression, viral yields in infected muscles, and improved muscle pathology. Additionally, we conducted a preliminary mechanism study using quantitative proteomics. The results suggested that the suppression of the PI3K/AKT/mTOR and NF-κB signaling pathways may contribute to the anti-EV-A71 activity of PZH. These findings provide strong evidence supporting the potential therapeutic application of PZH for EV-A71 infection management.

Stretchable, freezing-tolerant conductive hydrogel for wearable electronics reinforced by cellulose nanocrystals toward multiple hydrogen bonding.

Conductive hydrogels have the mechanical properties and the electronic transport properties of conductive polymers, which have been widely used in the fields of energy storage and bioelectronics. However, the rigidity and brittleness of conductive polymers hinder the long-term stability of hydrogels and limit its application in new flexible electronic devices. It is a high challenging task to prepare ion-conductive hydrogels with excellent mechanical properties, anti-freeze and electrical conductivity through a simple preparation process under the action of hydrogen bonds. We present a facile strategy to prepare mechanically tough, swelling ability hydrogels reinforced by cellulose nanocrystals (CNCs). Herein, CNCs were produced by high pressure homogeneous and pretreated with deep eutectic solvent (DES). The conductivity of the hydrogel is 0.021 S/cm at room temperature. Due to the function of DMSO/H2O in organic solvent system, the ion-conducting hydrogel remains flexible and conductive (0.014 S/cm) at -70 °C. Hydrogel has excellent mechanical properties (stress about 1.4 MPa, strain about 1018%), excellent transparency, freezing resistance (-70 °C) and other comprehensive characteristics. The hydrogel can be assembled into a sensor for use in monitoring large and small movements of the human body, showing good responsiveness and stability.

Cellulose nanocrystalline hydrogel based on a choline chloride deep eutectic solvent as wearable strain sensor for human motion.

Owning to the viscoelastic properties, good biocompatibility and high strain sensitivity, choline chloride-based deep eutectic solvent (DES) hydrogels have been considered to be promising wearable strain sensors for human motion. However, traditional hydrogels are far away from the wearable strain sensor applications caused by their unsatisfied conductivity and weak mechanical properties. Herein, the strategy for functional ionic inorganic/organic interpenetrating (IPN) hydrogels preparation by cyclic freezing/thawing method was successfully developed. Polyvinyl alcohol (PVA) was proposed to dissolve in choline chlorede-based DES as hydrogel matrix for the first time. Encouragingly, the obtained DES/PVA/CNCs/g-C3N4 hydrogel (choline chloride with glucose) exhibits excellent mechanical properties, included excellent tensile strength (≈ 2.55 MPa), high elongation (≈1200 %) and satisfactory tensile modulus (≈3.65 MPa). Interestingly, the thermal diffusivity (the maximum value was 0.675 W/mK) and conductivity (the maximum value was 0.18 mm2/s) of the DES-hydrogels were successfully achieved through adding graphitic-like nitride nanosheet (g-C3N4) and sustainable cellulose nanocrystalline (CNCs). These enhancements were attributed to the synergistic interactions of powerful hydrogen bonding among DES, CNCs, g-C3N4 and PVA chains. More importantly, the as-prepared hydrogels have the potential as a human motion sensor to accurately in-situ detect human activities on the fingers, wrists, elbows and knee joints. Those hydrogel-type strain sensors with flexibility, excellent mechanical properties, self-recovery, good heat transfer, and electrical conductivity have broad application prospects in the fields of intelligent robot, bionic prostheses, and human care areas.

Microstructure and physiochemical properties of meat sausages based on nanocellulose-stabilized emulsions.

Here we prepared some meat sausages using soybean oil in pure liquid form or pre-emulsified form stabilized with nanocelluloses (NCs) to partially replace pork back-fat and investigated the effects of NC types (sisal cellulose nanofiber, cotton cellulose nanofiber, and cotton cellulose nanocrystal) on the physicochemical properties and microstructure of the sausages. The physicochemical properties, including cooking loss, water holding capacity (WHC), textural properties, and rheological behavior, were evaluated. The results show that the sausages with pre-emulsified oil exhibited much-improved water and fat binding capacities, with significantly increased hardness, springiness, and chewiness. Additionally, pre-emulsifying soybean oil provided a more compact structure with smaller cavities. The sausages with different NCs had no significant difference in textural and microstructural properties, whereas they presented different water and fat binding capacities. From the results, it is concluded that NC-based emulsions are a viable fat replacer for meat sausages by providing similar stability and textural attributes.

Recent Progress on Functional Genomics Research of Enterovirus 71.

Enterovirus 71 (EV71) is one of the main pathogens that causes hand-foot-and-mouth disease (HFMD). HFMD caused by EV71 infection is mostly self-limited; however, some infections can cause severe neurological diseases, such as aseptic meningitis, brain stem encephalitis, and even death. There are still no effective clinical drugs used for the prevention and treatment of HFMD. Studying EV71 protein function is essential for elucidating the EV71 replication process and developing anti-EV71 drugs and vaccines. In this review, we summarized the recent progress in the studies of EV71 non-coding regions (5' UTR and 3' UTR) and all structural and nonstructural proteins, especially the key motifs involving in viral infection, replication, and immune regulation. This review will promote our understanding of EV71 virus replication and pathogenesis, and will facilitate the development of novel drugs or vaccines to treat EV71.

Lycorine Derivative LY-55 Inhibits EV71 and CVA16 Replication Through Downregulating Autophagy.

Hand, foot, and mouth disease (HFMD) is a global health concern, especially in the Asia-Pacific region. HFMD caused by Enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16) infection is usually self-limited but occasionally leads to severe pulmonary edema, neurological complications, and even death. Unfortunately, no effective drugs are currently available in clinical practice for the prevention and treatment of HFMD. Thus, anti-HFMD drugs must be urgently developed. A previous study had reported that lycorine could inhibit EV71 replication. In the present study, we found that LY-55, a lycorine derivative, inhibited the replication of EV71 and CVA16 in vitro and provided partial protection to mice from EV71 infection, as indicated by the decreased viral load and protein expression levels in muscles, clinical scores, and increased survival rates of infected mice. Mechanistically, LY-55 was not directly viricidal. Instead, the LY-55-mediated inhibition of EV71 and CVA16 was found to be mechanistically possible, at least in part, through downregulating autophagy, which plays an important role for EV71 and CVA16 replication. These findings suggest that LY-55 could be a potential lead or supplement for the development of anti-HFMD agents in the future.

APOBEC3G is a restriction factor of EV71 and mediator of IMB-Z antiviral activity.

Enterovirus 71 (EV71), a single-stranded positive-sense RNA virus, is the causative agent of hand, foot, and mouth disease (HFMD), for which no effective antiviral therapy is currently available. Apolipoprotein B messenger RNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G or A3G) is a cytidine deaminase that inhibits the replication of several viruses, such as human immunodeficiency virus-1, hepatitis B virus and hepatitis C virus. In our efforts toward understanding the antiviral spectrum and mechanism of A3G, we found that ectopic expression of A3G inhibited EV71 replication, whereas knockdown of endogenous A3G expression promoted EV71 replication. Moreover, inhibition of EV71 replication by IMB-Z, a N-phenylbenzamide derivative, is associated with increased levels of intracellular A3G, but reducing the level of A3G by RNA interference diminished the antiviral activity of IMB-Z. Mechanistically, we obtained evidence suggesting that the cytidine deaminase activity is not required for A3G inhibition of EV71 replication. Instead, we demonstrated that A3G can interact with viral 3D RNA-dependent RNA polymerase (RdRp) and viral RNA and be packaged into progeny virions to reduce its infectivity. Taken together, our results indicate that A3G is a cellular restriction factor of EV71 and mediator of the antiviral activity of IMB-Z. Pharmacological induction and/or stabilization of A3G is a potential therapeutic approach to treat diseases caused by EV71 infection, such as HFMD.

Conductive hydrogel composed of 1,3,5-benzenetricarboxylic acid and Fe3+ used as enhanced electrochemical immunosensing substrate for tumor biomarker.

In this work, a new conductive hydrogel was prepared by a simple cross-linking coordination method using 1,3,5-benzenetricarboxylic acid as the ligand and Fe3+ as the metal ion. The hydrogel film was formed on a glassy carbon electrode (GCE) by a drop coating method, which can dramatically facilitate the transport of electrons. A sensitive label-free electrochemical immunosensor was fabricated following electrodeposition of gold nanoparticles (AuNPs) on a hydrogel film and immobilization of an antibody. Neuron-specific enolase (NSE), a lung cancer biomarker, was used as the model analyte to be detected. The proposed immunosensor exhibited a wide linear detection range of 1pgmL-1 to 200ngmL-1 and a limit of detection of 0.26pgmL-1 (the ratio of signal to noise (S/N)=3). Moreover, the detection of NSE in human serum samples showed satisfactory accuracy compared with the data determined by enzyme-linked immunosorbent assay (ELISA), indicating good analytical performance of the immunoassay.

Polyhydroquinone-graphene composite as new redox species for sensitive electrochemical detection of cytokeratins antigen 21-1.

Polyhydroquinone-graphene composite as a new redox species was synthesized simply by a microwave-assisted one-pot method through oxidative polymerization of hydroquinone by graphene oxide, which exhibited excellent electrochemical redox activity at 0.124 V and can remarkably promote electron transfer. The as-prepared composite was used as immunosensing substrate in a label-free electrochemical immunosensor for the detection of cytokeratins antigen 21-1, a kind of biomarker of lung cancer. The proposed immunosensor showed wide liner range from 10 pg mL(-1) to 200 ng mL(-1) with a detection limit 2.3 pg mL(-1), and displayed a good stability and selectivity. In addition, this method has been used for the analysis of human serum sample, and the detection results showed good consistence with those of ELISA. The present substrate can be easily extended to other polymer-based nanocomposites.