Project description:The main goal of this study is to characterize the transcriptional modulations induced by antiviral compounds derived from chloroquine on Huh7 cells infected with HCV. And thus to identify among the genes modulated by infection, those who are regulated by chloroquine and potentially involved in the antiviral activity of the compound.Two HCV cell models were used: a non-infectious HCV replicon and the infectious HCV cell culture (HCVcc). In addition, this study aimed to highlight the characteristics of derivatives of antiviral chloroquine, compared with chloroquine itself. Abstract from the associated publication: Autophagy is a process of self-degradation of cellular components in which double-membrane autophagosomes sequester organelles or portion of cytosol and fuse with lysosomes or vacuoles for breakdown by resident hydrolases. Autophagy is upregulated in response to extra- or intracellular stress and signals such as starvation, growth factor deprivation, ER stress, and pathogen infection. Indeed, infection with hepatitis C virus (HCV) was shown to induce autophagy through ER stress signaling and subsequent Unfolded Protein Response (UPR) activation. Moreover, a role of autophagy in promoting HCV infection has been suggested and chloroquine (CQ), a lysosomal protease inhibitor, has been seen blocking autophagy as well as inhibiting HCV replication. In the present report, mechanisms accounting for these inhibitory effects were investigated. Gene expression profiling was performed on CQ treated JFH-1-infected Huh7 cells to identify the host cellular genes that are transcriptionally regulated by infection, and silenced by CQ-based treatment. Herein, we demonstrate that CQ reduces the expression of genes induced by the viral infection such as those encoding autophagic key factors triggering the turn-off of mTOR activity as well as factors involved in p53 and NF-KappaB activities. However, we present several lines of evidence demonstrating that the CQ repressive effect observed on the HCV-induced pathways results from a decrease of ER stress due to the upstream pH-dependent inhibitory effect of CQ on viral replication. Gene expression modulations were measured in Huh7 harboring replicon cells stimulated with a 10M-BM-5M of a Chloroquine derivative compound called CQd, during 6h, 12h and 24h. Two independent experiments were performed at each time. An untreated control condition was performed in each experiment, expression was measured at the 24h time point. For the HCVcc model, gene expression analysis was analyzed in two conditions: infection and treatment of infected cells. To characterize modulations in time course of infection, Huh7 naM-CM-/ve cells were infected with JFH1/CS-N6-A4 viral stock and gene expression was measured at 6h, 24h and 48h postinfection. For each kinetic time point, an uninfected condition was performed and gene expression was measured. An additional control testing the interferon (IFN) induced modulations on infected cells was included and gene expression was measured after a 48h stimulation with 100 IU of IFN (alpha 2 b). To characterize the antiviral modulations resulting from treatment with Chloroquine (CQ) or a derivative compound (CQd), gene expression was measured in JFH1/CS-N6-A4 infected Huh7 cells treated with 40M-BM-5M of CQ or CQd during 12h or 48h post-treatment and infection. For each kinetic time point 12h and 48h, an untreated infected control was also performed and gene expression measured.

Project description:To determine the transcriptional effects of a novel plant-based compound, dehydrobrachylaenolide, on P. falciparum, parasite cultures were treated with the compound over time. Samples were taken for analysis 2, 6, and 12 hours post-invasion of human red blood cells. Control cultures were treated simultaneously with DMSO, and samples isolated at 2, 6, and 12 hours for transcriptional analysis. Background Antimalarial drug resistance threatens to undermine efforts to eliminate this deadly disease. The resulting omnipresent requirement for drugs with novel modes of action prompted a national consortium initiative to discover new antiplasmodial agents from South African medicinal plants. One of the plants selected for investigation was Dicoma anomala subsp. gerrardii, based on its ethnomedicinal profile. Methods Standard phytochemical analysis techniques including solvent-solvent extraction, thin-layer and column chromatography, were used to isolate the main active constituent of Dicoma anomala subsp. gerrardii. The crystallised pure compound was identified using nuclear magnetic resonance spectroscopy, mass spectrometry and X-ray crystallography. The compound was tested in vitro on Plasmodium falciparum cultures using the parasite lactate dehydrogenase assay. The effects of treatment on the P. falciparum transcriptome were subsequently investigated by treating ring-stage parasites (alongside untreated controls) with the pure compound, followed by oligonucleotide microarray and data analysis. Results The main active constituent was identified as dehydrobrachylaenolide, a eudesmanolide-type sesquiterpene lactone. The compound demonstrated an in vitro IC50 of 245.6 nM, which was comparable to the IC50 of chloroquine, against a chloroquine-resistant strain (K1) of P. falciparum. Microarray data analysis identified a cluster of unique genes that were differentially expressed as a result of the treatment and gene ontology analysis identified various biological processes that were significantly affected. Comparison of the dehydrobrachylaenolide treatment transcriptional dataset with a published artesunate (also a sesquiterpene lactone) dataset revealed little overlap. This suggests differentiated modes of action between the two compounds. Conclusions Dehydrobrachylaenolide could play a valuable role as a drug candidate to generate new antimalarial compounds with novel modes of action and favourable ADMET properties.

Project description:The main goal of this study is to characterize the transcriptional modulations induced by antiviral compounds derived from chloroquine on Huh7 cells infected with HCV. And thus to identify among the genes modulated by infection, those who are regulated by chloroquine and potentially involved in the antiviral activity of the compound.Two HCV cell models were used: a non-infectious HCV replicon and the infectious HCV cell culture (HCVcc). In addition, this study aimed to highlight the characteristics of derivatives of antiviral chloroquine, compared with chloroquine itself. Abstract from the associated publication: Autophagy is a process of self-degradation of cellular components in which double-membrane autophagosomes sequester organelles or portion of cytosol and fuse with lysosomes or vacuoles for breakdown by resident hydrolases. Autophagy is upregulated in response to extra- or intracellular stress and signals such as starvation, growth factor deprivation, ER stress, and pathogen infection. Indeed, infection with hepatitis C virus (HCV) was shown to induce autophagy through ER stress signaling and subsequent Unfolded Protein Response (UPR) activation. Moreover, a role of autophagy in promoting HCV infection has been suggested and chloroquine (CQ), a lysosomal protease inhibitor, has been seen blocking autophagy as well as inhibiting HCV replication. In the present report, mechanisms accounting for these inhibitory effects were investigated. Gene expression profiling was performed on CQ treated JFH-1-infected Huh7 cells to identify the host cellular genes that are transcriptionally regulated by infection, and silenced by CQ-based treatment. Herein, we demonstrate that CQ reduces the expression of genes induced by the viral infection such as those encoding autophagic key factors triggering the turn-off of mTOR activity as well as factors involved in p53 and NF-KappaB activities. However, we present several lines of evidence demonstrating that the CQ repressive effect observed on the HCV-induced pathways results from a decrease of ER stress due to the upstream pH-dependent inhibitory effect of CQ on viral replication.

Dataset Information

Calcium dysregulation is the critical initiator in high dose chloroquine-induced programmed cell death of Plasmodium falciparum

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets