Mitochondrial dysfunction underlying sporadic inclusion body myositis is ameliorated by the mitochondrial homing drug MA-5.

Sporadic inclusion body myositis (sIBM) is the most common idiopathic inflammatory myopathy, and several reports have suggested that mitochondrial abnormalities are involved in its etiology. We recruited 9 sIBM patients and found significant histological changes and an elevation of growth differential factor 15 (GDF15), a marker of mitochondrial disease, strongly suggesting the involvement of mitochondrial dysfunction. Bioenergetic analysis of sIBM patient myoblasts revealed impaired mitochondrial function. Decreased ATP production, reduced mitochondrial size and reduced mitochondrial dynamics were also observed in sIBM myoblasts. Cell vulnerability to oxidative stress also suggested the existence of mitochondrial dysfunction. Mitochonic acid-5 (MA-5) increased the cellular ATP level, reduced mitochondrial ROS, and provided protection against sIBM myoblast death. MA-5 also improved the survival of sIBM skin fibroblasts as well as mitochondrial morphology and dynamics in these cells. The reduction in the gene expression levels of Opa1 and Drp1 was also reversed by MA-5, suggesting the modification of the fusion/fission process. These data suggest that MA-5 may provide an alternative therapeutic strategy for treating not only mitochondrial diseases but also sIBM.

Inhibition of the DNA polymerase and RNase H activities of HIV-1 reverse transcriptase and HIV-1 replication by Brasenia schreberi (Junsai) and Petasites japonicus (Fuki) components.

Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) possesses two distinct enzymatic activities: those of RNA- and DNA-dependent DNA polymerases and RNase H. In the current HIV-1 therapy, all HIV-1 RT inhibitors inhibit the activity of DNA polymerase, but not that of RNase H. We previously reported that ethanol and water extracts of Brasenia schreberi (Junsai) inhibited the DNA polymerase activity of HIV-1 RT [Hisayoshi et al. (2014) J Biol Macromol 14:59-65]. In this study, we screened 43 edible plants and found that ethanol and water extracts of Brasenia schreberi and water extract of Petasites japonicus strongly inhibit not only the activity of DNA polymerase to incorporate dTTP into poly(rA)-p(dT)15 but also the activity of RNase H to hydrolyze the RNA strand of an RNA/DNA hybrid. In addition, these three extracts inhibit HIV-1 replication in human cells, with EC50 values of 1-2 µg/ml. These results suggest that Brasenia schreberi and Petasites japonicus contain substances that block HIV-1 replication by inhibiting the DNA polymerase activity and/or RNase H activity of HIV-1 RT.

A simple, rapid, and sensitive system for the evaluation of anti-viral drugs in rats.

The lack of small animal models for the evaluation of anti-human immunodeficiency virus type 1 (HIV-1) agents hampers drug development. Here, we describe the establishment of a simple and rapid evaluation system in a rat model without animal infection facilities. After intraperitoneal administration of test drugs to rats, antiviral activity in the sera was examined by the MAGI assay. Recently developed inhibitors for HIV-1 entry, two CXCR4 antagonists, TF14016 and FC131, and four fusion inhibitors, T-20, T-20EK, SC29EK, and TRI-1144, were evaluated using HIV-1(IIIB) and HIV-1(BaL) as representative CXCR4- and CCR5-tropic HIV-1 strains, respectively. CXCR4 antagonists were shown to only possess anti-HIV-1(IIIB) activity, whereas fusion inhibitors showed both anti-HIV-1(IIIB) and anti-HIV-1(BaL) activities in rat sera. These results indicate that test drugs were successfully processed into the rat sera and could be detected by the MAGI assay. In this system, TRI-1144 showed the most potent and sustained antiviral activity. Sera from animals not administered drugs showed substantial anti-HIV-1 activity, indicating that relatively high dose or activity of the test drugs might be needed. In conclusion, the novel rat system established here, "phenotypic drug evaluation", may be applicable for the evaluation of various antiviral drugs in vivo.

Epigallocatechin gallate inhibits the HIV reverse transcription step.

BACKGROUND: Epigallocatechin gallate (EGCG), the most abundant catechin in green tea, has been reported to inhibit HIV-1 replication prior to its integration into host DNA via various proposed mechanisms; however, the specific main target(s) of EGCG remain unclear. In this study, we investigated a number of these proposed detailed mechanism(s) using a cell-based model. METHODS: Multinuclear activation of galactosidase indicator assays were used for all experiments, including examination of the time of addition and the synergisms with a nucleoside reverse transcriptase inhibitor, 3'-azido-3'-deoxythymidine (AZT). RESULTS: The experiments revealed that EGCG suppressed both HIV-1(IIIB) and HIV-2(EHO) infection in HeLa-CD4-LTR-ß-gal cells, with relatively low 50% effective concentrations of 1.6 and 2.0 µM, respectively. The inhibitory profile of EGCG generated using a time-of-addition assay was identical to that of a non-nucleoside reverse transcriptase inhibitor (NNRTI), MKC-442. Furthermore, synergistic inhibition was observed in EGCG with AZT. CONCLUSIONS: Based on our findings, EGCG appears to act mainly as an allosteric reverse transcriptase inhibitor with mechanisms different from those of currently approved NNRTIs that directly interact with the NNRTI binding pocket. Thus, EGCG is a good candidate for use as an additional or supportive anti-HIV agent derived from natural plants.

Procyanidin B1 purified from Cinnamomi cortex suppresses hepatitis C virus replication.

BACKGROUND: A combination of pegylated interferon and ribavirin is the current standard therapy for hepatitis C virus (HCV) infection, but this combination provides relatively low efficacy, especially in some patients with HCV genotype 1 infection; therefore, the development of novel therapeutic agents is required for further improvement in the treatment of chronic HCV infection. METHODS: HCV pseudotype and subgenomic replicon assays were used in this study. The interaction of compounds with HCV receptors was examined using flow cytometry. Intracellular RNA levels were determined by semi-quantitative reverse transcriptase PCR. RESULTS: Procyanidin B1 (PB1), a dimer of (-)-epicatechin and (+)-catechin, purified from Cinnamomi cortex, inhibits infection by vesicular stomatitis virus and HCV pseudotype virus in Huh-7 cells, with 50% effective concentrations of 29 and 15 microM, respectively. No inhibitory effects were observed in each component of PB1. We found that PB1 does not interfere with viral entry or receptor expression, but inhibits HCV RNA synthesis in a dose-dependent manner. CONCLUSIONS: These results indicate that PB1 suppresses HCV RNA synthesis, possibly as a HCV RNA polymerase inhibitor. Our results might contribute towards the development of more effective inhibitors for HCV infection from natural plants.