Evaluation of the virucidal effects of rosmarinic acid against enterovirus 71 infection via in vitro and in vivo study.

BACKGROUND: Although enterovirus 71 (EV71) is an important public health threat, especially in the Asia-Pacific region, there are still no effective drugs or vaccines to treat and prevent EV71 infection. Therefore, it is critical to develop prophylactic and therapeutic agents against EV71. Rosmarinic acid (RA), a phytochemical, has been discovered to possess a broad spectrum of biological activities. METHODS: The virucidal effects of RA on EV71 were determined by MTT, western blot, median cell culture infectious dose, apoptosis detection, plaque reduction, semi-quantitative real-time polymerase chain reaction, immunofluorescence detection, molecular docking analysis, and mouse protection assay. RESULTS: RA showed a strong protective effect against EV71 infection in human rhabdomyosarcoma cells when the multiplicity of infection was 1, with a low IC50 value (4.33 ± 0.18 µM) and high therapeutic index (340). RA not only protected cells from EV71-induced cytopathic effects, but also from EV71-induced apoptosis. The results of time-of-addition analysis demonstrated that the inhibitory activity of RA was highest at the early stage of viral infection. Consistent with this, the infectivity of EV71 in the early stage of viral infection also was observed to be limited in neonatal mice treated with RA. Further, molecular docking predicts that RA could replace the natural pocket factor within the VP1 capsid-binding hydrophobic pocket. CONCLUSIONS: This study suggests that RA has the potential to be developed as an antiviral agent against initial EV71 infection to prevent or reduce EV71-induced pathogenesis and complications, since RA can effectively reduce EV71 infection in the early stages of viral infection.

Tyrosine kinase SYK is a potential therapeutic target for liver fibrosis.

Spleen tyrosine kinase (SYK) plays a critical role in immune cell signaling pathways and has been reported as a biomarker for human hepatocellular carcinoma (HCC). We sought to investigate the mechanism by which SYK promotes liver fibrosis and to evaluate SYK as a therapeutic target for liver fibrosis. We evaluated the cellular localization of SYK and the association between SYK expression and liver fibrogenesis in normal, hepatitis B virus (HBV)-infected, hepatitis C virus (HCV)-infected and non-alcoholic steatohepatitis (NASH) liver tissue (n=36, 127, 22 and 30, respectively). A polymerase chain reaction (PCR) array was used to detect the changes in transcription factor (TF) expression in hepatic stellate cells (HSCs) with SYK knockdown. The effects of SYK antagonism on liver fibrogenesis were studied in LX-2 cells, TWNT-4 cells, primary human HSCs, and three progressive fibrosis/cirrhosis animal models, including a CCL4 mouse model, and diethylnitrosamine (DEN) and bile duct ligation (BDL) rat models. We found that SYK protein in HSCs and hepatocytes correlated positively with liver fibrosis stage in human liver tissue. HBV or HCV infection significantly increased SYK and cytokine expression in hepatocytes. Increasing cytokine production further induced SYK expression and fibrosis-related gene transcription in HSCs. Up-regulated SYK in HSCs promoted HSC activation by increasing the expression of specific TFs related to activation of HSCs. SYK antagonism effectively suppressed liver fibrosis via inhibition of HSC activation, and decreased obstructive jaundice and reduced HCC development in animal models. Conclusion: SYK promotes liver fibrosis via activation of HSCs and is an attractive potential therapeutic target for liver fibrosis and prevention of HCC development. (Hepatology 2018).

Prevalence, characteristics, mapping, and catheter ablation of potential rotors in nonparoxysmal atrial fibrillation.

BACKGROUND: Identification of critical atrial substrates in patients with nonparoxysmal atrial fibrillation (AF) failing to respond to pulmonary vein isolation is important. This study investigated the signal characteristics, substrate nature, and ablation results of rotors during AF. METHODS AND RESULTS: In total, 53 patients (age=55±8), 31 with persistent AF and 22 with long-lasting AF, underwent pulmonary vein isolation and substrate modification of complex fractionated atrial electrograms. Small-radius-reentrant rotors were identified from signal analyses of the dominant frequency and fractionation interval and nonlinear analyses (newly developed, beat-to-beat nonlinear measurement of the repetitiveness of the electrogram morphology>6 seconds). In 15% of the patients, activation maps demonstrated occurrences of rotor-like small-radius reentrant circuits (n=9; 1.1 per patient; cycle length=110±21 ms; diameter=11±6 mm) with fibrillation occurring outside these areas. Rotors were identified by conventional point-by-point mapping and signal analyses and were subsequently eradicated by catheter ablation in these patients. Persistent AF for <1 year, a smaller left atrial size, substrates with higher mean voltages and shorter total activation durations predicted a higher incidence of rotors (all P<0.05). In the multivariable model, areas of reentrant circuits exhibited a higher dominant frequency, kurtosis, and higher degree of a beat-to-beat electrogram similarity than areas without or outside the rotors (all P<0.05). CONCLUSIONS: Rotor-like re-entry with fibrillatory conduction was found in a limited number of patients with nonparoxysmal AF after pulmonary vein isolation. Those areas were characterized by rapid repetitive activity with a high degree of electrogram similarity.

Magnesium lithospermate B mediates anti-inflammation targeting activator protein-1 and nuclear factor-kappa B signaling pathways in human peripheral T lymphocytes.

The activation of T lymphocytes contributes to the inflammatory processes of atherosclerotic diseases. Danshen is a traditional Chinese medicine and has shown therapeutic effects in patients with cardiovascular and cerebrovascular diseases. We investigated the effects of aqueous extract of Danshen (magnesium lithospermate B (MLB)) on phorbol 12-myristate acetate+ionomycin and anti-CD3+anti-CD28 monoclonal antibody-activated T cells. We showed that MLB inhibited interleukin (IL)-2, IL-4, tumor necrosis factor-alpha and interferon-gamma production from activated T cells. The expressions of T cell activation markers CD 25 and CD 69 were effectively reduced. EMSA analysis indicated that MLB down-regulated activator protein-1 (AP-1), nuclear factor kappa B (NF-κB) and octamer binding transcription factor (Oct-1) DNA-binding activity. In addition, MLB inhibited c-jun N-terminal kinase (JNK) but not extracellular signal regulated protein kinase activity. MLB also inhibited IκBα degradation, nuclear translocation of p65 and p50 as well as decreased IκBα kinase (IKK) activity. Through suppressing JNK-AP-1, IKK-IκBα-NF-κB and Oct-1 signaling pathways by MLB in activated T cells, our results provide support for efficacy of MLB in inflammatory diseases and raise its therapeutic potential in activated T cell-mediated pathologies.

Rapid authentication of Bupleurum species using an array of immobilized sequence-specific oligonucleotide probes.

Standardization and modernization of Chinese medicinal herbs are limited partially by misidentification of processed materials. Our goal was to develop an efficient method for verification of Chinese medicinal herbs, based on the variable sites of the rDNA internal transcribed spacer (ITS) region. We analyzed sequence differences in ITS of three Bupleurum species, B. kaoi Liu Chao et Chuang, B. falcatum L. and B. chinense DC., and developed a rapid detection method using a sequence-specific oligonucleotide probe (SSOP) array. The SSOP array, composed of poly-T tailed sequence-specific oligonucleotides, was hybridized to the digoxigenin (DIG)-labeled target ITS DNA of the Bupleurum species. The detected signals corresponded precisely to the specific sequences. This array provides a reliable and economical method for authenticating a large number of Chinese medicinal herbs. The short duration of the procedure (within 30 h) makes it an especially useful tool in verifying processed plant material.

Identification of novel epoxide inhibitors of hepatitis C virus replication using a high-throughput screen.

Using our high-throughput hepatitis C replicon assay to screen a library of over 8,000 novel diversity-oriented synthesis (DOS) compounds, we identified several novel compounds that regulate hepatitis C virus (HCV) replication, including two libraries of epoxides that inhibit HCV replication (best 50% effective concentration, < 0.5 microM). We then synthesized an analog of these compounds with optimized activity.

Antitubercular constituents from the roots of Engelhardia roxburghiana.

Three new compounds, engelhardione, (-)-5-hydroxy-4-methoxy-1-tetralone, and 3-methoxycarbonyl-1,5-dihydroxyanthraquinone, together with twelve known compounds have been isolated from the roots of Engelhardia roxburghiana. The structures of these new compounds were determined through spectral analyses. Engelhardione, 3-methoxyjuglone, and (-)-4-hydroxy-1-tetralone showed antitubercular activities with MIC values=3.125, 3.125, and 6.25 microg/mL against Mycobacterium tuberculosis 90-221,387, respectively, and with MIC values=0.2, 0.2, and 4.0 microg/mL against M. tuberculosis H37Rv, individually.