[1,2,4]Triazolo[1,5-a]pyrimidine derivative (Mol-5) is a new NS5-RdRp inhibitor of DENV2 proliferation and DENV2-induced inflammation.

Dengue fever is an acute infectious disease caused by dengue virus (DENV) and transmitted by Aedes mosquitoes. There is no effective vaccine or antiviral drug available to date to prevent or treat dengue disease. Recently, RNA-dependent RNA polymerase (RdRp), a class of polymerases involved in the synthesis of complementary RNA strands using single-stranded RNA, has been proposed as a promising drug target. Hence, we screened new molecules against DENV RdRp using our previously constructed virtual screening method. Mol-5, [1,2,4]triazolo[1,5-a]pyrimidine derivative, was screened out from an antiviral compound library (~8000 molecules). Using biophysical methods, we confirmed the direct interactions between mol-5 and purified DENV RdRp protein. In luciferase assay, mol-5 inhibited NS5-RdRp activity with an IC50 value of 1.28 ± 0.2 µM. In the cell-based cytopathic effect (CPE) assay, mol-5 inhibited DENV2 infectivity with an EC50 value of 4.5 ± 0.08 µM. Mol-5 also potently inhibited DENV2 RNA replication as observed in immunofluorescence assay and qRT-PCR. Both the viral structural (E) and non-structural (NS1) proteins of DENV2 were dose-dependently decreased by treatment with mol-5 (2.5-10 µM). Mol-5 treatment suppressed DENV2-induced inflammation in host cells, but had no direct effect on host defense (JAK/STAT-signaling pathway). These results demonstrate that mol-5 could be a novel RdRp inhibitor amenable for further research and development.

[ADS-J1 antagonizes semen-derived enhancer of virus infection-mediated enhancement of transmitted founder HIV-1 and its matched chronic control strain infection].

OBJECTIVE: To investigate the effect of semen-derived enhancer of virus infection (SEVI) on the infection of transmitted/founder (TF) HIV-1 and its matched chronic control (CC) viruses and the antagonism of ADS-J1 on SEVI-mediated enhancement of TF and CC virus infection in vitro. METHODS: PAP248-286 self-assembling into SEVI amyloid fibrils was validated by ThT assay. We generated the virus stocks of TF and CC virus pair. TZM-bl cells were infected with the mixture of SEVI and TF or CC viruses for 72 h. Luciferase activity was used to observe the enhancement of SEVI. SEVI was treated with different concentrations of ADS-J1 and incubated with TF or CC viruses. TZM-bl cells were then infected with the mixture and luciferase activity was detected 72 h after infection to analyze the antagonism of ADS-J1 on the enhancing effect of SEVI. ADS-J1 was also incubated with TF and CC viruses directly and TZM-bl cells were infected for 72 h to evaluate the antiviral effect using luciferase assay. SEVI was treated with ADS-J1 and Zeta potential was determined to explore the antagonistic mechanism of ADS-J1. RESULTS: ThT assay showed that PAP248-286 was capable of self-assembly into SEVI amyloid fibrils. SEVI significantly accelerated TF and CC viruses infection (P<0.05), and ADS-J1 not only significantly antagonized the enhancement of SEVI (P<0.05) but also directly inhibited the infection of TF and CC viruses (P<0.05). ADS-J1 neutralized the positive charge of SEVI in a dose-dependent manner. CONCLUSIONS: SEVI promotes the infection of TF and CC strains, and ADS-J1 antagonizes SEVI-mediated enhancement of TF and CC viruses by neutralizing the positive charge of SEVI.

BBT improves glucose homeostasis by ameliorating ß-cell dysfunction in type 2 diabetic mice.

Impaired glucose-stimulated insulin secretion (GSIS) and increasing ß-cell death are two typical dysfunctions of pancreatic ß-cells in individuals that are destined to develop type 2 diabetes, and improvement of ß-cell function through GSIS enhancement and/or inhibition of ß-cell death is a promising strategy for anti-diabetic therapy. In this study, we discovered that the small molecule, N-(2-benzoylphenyl)-5-bromo-2-thiophenecarboxamide (BBT), was effective in both potentiating GSIS and protecting ß-cells from cytokine- or streptozotocin (STZ)-induced cell death. Results of further studies revealed that cAMP/PKA and long-lasting (L-type) voltage-dependent Ca(2) (+) channel/CaMK2 pathways were involved in the action of BBT against GSIS, and that the cAMP/PKA pathway was essential for the protective action of BBT on ß-cells. An assay using the model of type 2 diabetic mice induced by high-fat diet combined with STZ (STZ/HFD) demonstrated that BBT administration efficiently restored ß-cell functions as indicated by the increased plasma insulin level and decrease in the ß-cell loss induced by STZ/HFD. Moreover, the results indicated that BBT treatment decreased fasting blood glucose and HbA1c and improved oral glucose tolerance further highlighting the potential of BBT in anti-hyperglycemia research.

Natural product vindoline stimulates insulin secretion and efficiently ameliorates glucose homeostasis in diabetic murine models.

ETHNOPHARMACOLOGICAL RELEVANCE: Catharanthus roseus (L). Don (Catharanthus roseus) is a traditional anti-diabetic herb widely used in many countries, and the alkaloids of Catharanthus roseus are considered to possess hypoglycemic ability. AIM OF THE STUDY: To systematically investigate the potential anti-diabetic effects and the underlying anti-diabetic mechanisms of vindoline, one of the alkaloids in Catharanthus roseus. MATERIALS AND METHODS: The regulation of vindoline against the glucose-stimulated insulin secretion (GSIS) was examined in insulinoma MIN6 cells and primary pancreatic islets. Insulin concentration was detected by Elisa assay. Diabetic models of db/db mice and type 2 diabetic rats induced by high-fat diet combining with streptozotocin (STZ/HFD-induced type 2 diabetic rats) were used to evaluate the anti-diabetic effect of vindoline in vivo. Daily oral treatment with vindoline (20mg/kg) to diabetic mice/rats for 4 weeks, body weight and blood glucose were determined every week, oral glucose tolerance test (OGTT) was performed after 4 weeks. RESULTS: Vindoline enhanced GSIS in both glucose- and dose-dependent manners (EC50 = 50 µM). It was determined that vindoline acted as a Kv2.1 inhibitor able to reduce the voltage-dependent outward potassium currents finally enhancing insulin secretion. It protected ß-cells from the cytokines-induced apoptosis following its inhibitory role in Kv2.1. Moreover, vindoline (20mg/kg) treatment significantly improved glucose homeostasis in db/db mice and STZ/HFD-induced type 2 diabetic rats, as reflected by its functions in increasing plasma insulin concentration, protecting the pancreatic ß-cells from damage, decreasing fasting blood glucose and glycated hemoglobin (HbA1c), improving OGTT and reducing plasma triglyceride (TG). CONCLUSION: Our findings suggested that vindoline might contribute to the anti-diabetic effects of Catharanthus roseus, and this natural product may find its more applications in the improvement of ß-cell dysfunction and further the potential treatment of type 2 diabetes.

Arctigenin effectively ameliorates memory impairment in Alzheimer's disease model mice targeting both ß-amyloid production and clearance.

Alzheimer's disease (AD) chiefly characterizes a progressively neurodegenerative disorder of the brain, and eventually leads to irreversible loss of intellectual abilities. The ß-amyloid (Aß)-induced neurodegeneration is believed to be the main pathological mechanism of AD, and Aß production inhibition or its clearance promotion is one of the promising therapeutic strategies for anti-AD research. Here, we report that the natural product arctigenin from Arctium lappa (L.) can both inhibit Aß production by suppressing ß-site amyloid precursor protein cleavage enzyme 1 expression and promote Aß clearance by enhancing autophagy through AKT/mTOR signaling inhibition and AMPK/Raptor pathway activation as investigated in cells and APP/PS1 transgenic AD model mice. Moreover, the results showing that treatment of arctigenin in mice highly decreased Aß formation and senile plaques and efficiently ameliorated AD mouse memory impairment strongly highlight the potential of arctigenin in anti-AD drug discovery.

(+)-Rutamarin as a dual inducer of both GLUT4 translocation and expression efficiently ameliorates glucose homeostasis in insulin-resistant mice.

Glucose transporter 4 (GLUT4) is a principal glucose transporter in response to insulin, and impaired translocation or decreased expression of GLUT4 is believed to be one of the major pathological features of type 2 diabetes mellitus (T2DM). Therefore, induction of GLUT4 translocation or/and expression is a promising strategy for anti-T2DM drug discovery. Here we report that the natural product (+)-Rutamarin (Rut) functions as an efficient dual inducer on both insulin-induced GLUT4 translocation and expression. Rut-treated 3T3-L1 adipocytes exhibit efficiently enhanced insulin-induced glucose uptake, while diet-induced obese (DIO) mice based assays further confirm the Rut-induced improvement of glucose homeostasis and insulin sensitivity in vivo. Subsequent investigation of Rut acting targets indicates that as a specific protein tyrosine phosphatase 1B (PTP1B) inhibitor Rut induces basal GLUT4 translocation to some extent and largely enhances insulin-induced GLUT4 translocation through PI3 kinase-AKT/PKB pathway, while as an agonist of retinoid X receptor α (RXRα), Rut potently increases GLUT4 expression. Furthermore, by using molecular modeling and crystallographic approaches, the possible binding modes of Rut to these two targets have been also determined at atomic levels. All our results have thus highlighted the potential of Rut as both a valuable lead compound for anti-T2DM drug discovery and a promising chemical probe for GLUT4 associated pathways exploration.