Identification and characterization of a new type of inhibitor against the human immunodeficiency virus type-1 nucleocapsid protein.

BACKGROUND: The human immunodeficiency virus type-1 (HIV-1) nucleocapsid protein (NC) is an essential and multifunctional protein involved in multiple stages of the viral life cycle such as reverse transcription, integration of proviral DNA, and especially genome RNA packaging. For this reason, it has been considered as an attractive target for the development of new anti-HIV drugs. Although a number of inhibitors of NC have been reported thus far, the search for NC-specific and functional inhibitor(s) with a good antiviral activity continues. RESULTS: In this study, we report the identification of A1752, a small molecule with inhibitory action against HIV-1 NC, which shows a strong antiviral efficacy and an IC50 around 1 µM. A1752 binds directly to HIV-1 NC, thereby inhibiting specific chaperone functions of NC including Psi RNA dimerization and complementary trans-activation response element (cTAR) DNA destabilization, and it also disrupts the proper Gag processing. Further analysis of the mechanisms of action of A1752 also showed that it generates noninfectious viral particles with defects in uncoating and reverse transcription in the infected cells. CONCLUSIONS: These results demonstrate that A1752 is a specific and functional inhibitor of NC with a novel mode of action and good antiviral efficacy. Thus, this agent provides a new type of anti-HIV NC inhibitor candidate for further drug development.

Correlation between surface hydrophilicity and osteoblastic differentiation on microgrooved titanium substrata.

Surface microgrooves and acid etching on titanium (Ti) have been proposed to enhance various cell behaviors. In this study, surface hydrophilicity, protein adsorption, and alkaline phosphatase activity of osteoblasts were analyzed and compared between microgrooved Ti, Ti with microgrooves and further acid etching, smooth Ti, and acid-etched smooth Ti. Correlations between the results of each experiment were analyzed using Pearson's correlation analysis, and the influential factor on alkaline phosphatase activity was determined using multiple stepwise regression analysis. Among groups, the Ti substrata with microgrooves and subsequent acid etching showed significantly greater surface hydrophilicity and alkaline phosphatase activity compared with smooth Ti, whereas the Ti substrata with only microgrooves showed the greatest protein adsorption. Multiple stepwise regression analysis determined the surface hydrophilicity of Ti as the influential factor on alkaline phosphatase activity. This study indicates that surface microgrooves and acid etching on Ti substrata enhance surface hydrophilicity, leading to increased alkaline phosphatase activity.

Identification of a novel type of small molecule inhibitor against HIV-1.

Here we report a new chemical inhibitor against HIV-1 with a novel structure and mode of action. The inhibitor, designated as A1836, inhibited HIV-1 replication and virus production with a 50% inhibitory concentration (IC50) of 2.0 µM in an MT-4 cell-based and cytopathic protection antiviral assay, while its 50% cytotoxic concentration (CC50) was much higher than 50 µM. Examination of the effect of A1836 on in vitro HIV-1 reverse transcriptase (RT) and integrase showed that neither were molecular targets of A1836. The characterization and re-infection assay of the HIV-1 virions generated in the presence of A1836 showed that the synthesis of early RT products in the cells infected with the virions was inhibited dose-dependently, due in part to abnormal protein formation within the virions, thus resulting in an impaired infectivity. These results suggest that A1836 might be a novel candidate for the development of a new type of HIV-1 inhibitor.

Identification of anti-HIV and anti-reverse transcriptase activity from Tetracera scandens.

We report here that an ethanol extract of Tetracera scandens, a Vietnamese medicinal plant, has anti-HIV activity and possesses strong inhibitory activity against HIV-1 reverse transcriptase (RTase). Using a MT-4 cell-based assay, we found that the T. scandens extract inhibited effectively HIV virus replication with an IC(50) value in the range of 2.0-2.5 µg/ml while the cellular toxicity value (CC50) was more than 40-50 µg/ml concentration, thus yielding a minimum specificity index of 20-fold. Moreover, the anti-HIV efficacy of the T. scandens extract was determined to be due, in part, to its potent inhibitory activity against HIV-1 RTase activity in vitro. The inhibitory activity against the RTase was further confirmed by probing viral cDNA production, an intermediate of viral reverse transcription, in virus-infected cells using quantitative DNA-PCR analysis. Thus, these results suggest that T. scandens can be a useful source for the isolation and development of new anti- HIV-1 inhibitor(s). [BMB reports 2012; 45(3): 165-170].

Effect of etched microgrooves on hydrophilicity of titanium and osteoblast responses: A pilot study.

PURPOSE: The aim of this pilot study was to investigate the effect of etched microgrooves on the hydrophilicity of Ti and osteoblast responses. MATERIAL AND METHODS: Microgrooves were applied on Ti to have 15 and 60 µm width, and 3.5 and 10 µm depth by photolithography, respectively. Further acid etching was applied to create Ti surfaces with etched microgrooves. Both smooth- and acid-etched Ti were used as the controls. The hydrophilicity of Ti was analyzed by determining contact angles. Cell proliferation and osteogenic activity of MC3T3 mouse preosteoblasts were analyzed by bromodeoxyuridine assay and alkaline phosphatase (ALP) activity test, respectively. One-way ANOVA, Pearson's correlation analysis and multiple regression analysis were used for statistics. RESULTS: Etched microgrooves significantly increased the hydrophilicity of Ti compared to the smooth Ti. 60 µm-wide etched microgrooves significantly enhanced cell proliferation, whereas the osteogenic activity showed statistically non-significant differences between groups. Result of the osteogenic activity significantly correlated with those of hydrophilicity and cell proliferation. Hydrophilicity was determined to be an influential factor on osteogenic activity. CONCLUSION: This study indicates that increase in hydrophilicity of Ti caused by etched microgrooves acts as an influential factor on osteogenic activity. However, statistically non-significant increase in the ALP activity suggests further investigation.

Anti-inflammatory effects of BT-201, an n-butanol extract of Panax notoginseng, observed in vitro and in a collagen-induced arthritis model.

BACKGROUND & AIMS: Although there has been some success with protein-based anti-tumor necrosis factor alpha (TNF-alpha) therapeutics, the problems associated with protein-based drugs demand alternative approaches. We screened various herbal extracts for their ability to inhibit TNF-alpha secretions and found that BT-201, an n-butanol extract of Panax notoginseng (Burk.) F. H. Chen (P. notoginseng) has such an ability. METHODS: The purpose of this study has been to evaluate the anti-inflammatory and anti-rheumatic effects of BT-201. The anti-inflammatory effects were evaluated by measuring the effects of BT-201 on the production of TNF-alpha, interleukin (IL)-1beta, inducible nitric oxide (iNO), and matrix metalloproteinase-13 (MMP-13), in vitro. The anti-rheumatic effects were evaluated by treating mice with collagen-induced arthritis (CIA) using a daily oral administration of BT-201 at 15 mg/kg/day. In addition, the effects on NF-kappaB and mitogen-activated protein kinase (MAPK) pathways were evaluated by Western blotting using phospho-specific antibodies. RESULTS: BT-201 significantly inhibited all the inflammatory parameters evaluated in vitro and delayed the onset and progression of CIA. BT-201 inhibited the activation of NF-kappaB, ERK, p38, and JNK pathways. CONCLUSIONS: Our results demonstrated that BT-201 can modulate various aspects of inflammation in vitro and that it has disease-modifying, anti-rheumatic effects in vivo, suggesting that it can be a potential alternative to the current anti-TNF-alpha therapeutics for rheumatoid arthritis and other inflammatory disease.