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Author

Binay Chaubey

Other affiliations: Gdańsk Medical University
Bio: Binay Chaubey is an academic researcher from University of Calcutta. The author has contributed to research in topics: NS5B & Viral replication. The author has an hindex of 9, co-authored 15 publications receiving 214 citations. Previous affiliations of Binay Chaubey include Gdańsk Medical University.

Papers
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Journal ArticleDOI
TL;DR: The results indicate that anti-HIV-1 PNA conjugated with MTD peptides are not only inhibitory to HIV-1 replication in vitro but are also potent virucidal agents which render HIV- 1 virions non-infectious upon brief exposure.
Abstract: The transactivator responsive region (TAR) present in the 5'-NTR of the HIV-1 genome represents a potential target for antiretroviral intervention and a model system for the development of specific inhibitors of RNA-protein interaction. Earlier, we have shown that an anti-TAR polyamide nucleotide analog (PNA(TAR)) conjugated to a membrane transducing (MTD) peptide, transportan, is efficiently taken up by the cells and displays potent antiviral and virucidal activity [B. Chaubey, S. Tripathi, S. Ganguly, D. Harris, R. A. Casale and V. N. Pandey (2005) Virology, 331, 418-428]. In the present communication, we have conjugated five different MTD peptides, penetratin, tat peptide, transportan-27, and two of its truncated derivatives, transportan-21 and transportan-22, to a 16mer PNA targeted to the TAR region of the HIV-1 genome. The individual conjugates were examined for their uptake efficiency as judged by FACScan analysis, uptake kinetics using radiolabeled conjugate, virucidal activity and antiviral efficacy assessed by inhibition of HIV-1 infection/replication. While FACScan analysis revealed concentration-dependent cellular uptake of all the PNA(TAR)-peptide conjugates where uptake of the PNA(TAR)-penetratin conjugate was most efficient as >90% MTD was observed within 1 min at a concentration of 200 nM. The conjugates with penetratin, transportan-21 and tat-peptides were most effective as an anti-HIV virucidal agents with IC50 values in the range of 28-37 nM while IC50 for inhibition of HIV-1 replication was lowest with PNA(TAR)-transportan-27 (0.4 microM) followed by PNA(TAR)-tat (0.72 microM) and PNA(TAR)-penetratin (0.8 microM). These results indicate that anti-HIV-1 PNA conjugated with MTD peptides are not only inhibitory to HIV-1 replication in vitro but are also potent virucidal agents which render HIV-1 virions non-infectious upon brief exposure.

53 citations

Journal ArticleDOI
TL;DR: It is hypothesized that EFV being a lipophilic molecule is internalized into the mitochondrial compartment causing depolarization of Δψm which subsequently leads to a cascade of events causing cell death in EFV-treated cells.
Abstract: Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and an active constituent of the highly active antiretroviral therapy regime. It has significantly contributed in control and management of human immunodeficiency virus propagation. However, EFV administration has also led to severe adverse effects, several reports highlighted the role of EFV in mitochondrial dysfunction and toxicity but the molecular mechanism has been poorly understood. In present study, human hepatoma cells Huh 7.5 were treated with clinically relevant concentrations of EFV and parameters like cytotoxicity, mitochondrial transmembrane potential, mitochondrial morphology, cytochrome c release, mitochondria-mediated apoptosis, mtDNA and mtRNA levels and EFV distribution into mitochondrial compartment were evaluated to understand sequence of events leading to cell death in EFV-treated cells. EFV at its clinically relevant concentration was significantly toxic after 48 and 72 h of treatments. EFV-mediated toxicity is initiated with the permeabilization of mitochondrial outer membrane and change in mitochondrial membrane potential (Δψm) which triggers a series of events like cytochrome c release, alteration in mitochondrial morphology and mitochondria-mediated apoptosis. Total mitochondrial content is reduced after 48 h of EFV treatment at IC50 concentration which is also reflected in reduced mitochondrial DNA and RNA levels. After detecting EFV in mitochondrial compartment after 12 h of incubation with EFV, we hypothesize that EFV being a lipophilic molecule is internalized into the mitochondrial compartment causing depolarization of Δψm which subsequently leads to a cascade of events causing cell death.

51 citations

Journal ArticleDOI
TL;DR: The present and future therapeutic potential of this class of compound as anti-HIV-1 drugs as well as potential antisense drugs are discussed.
Abstract: Since the discovery and synthesis of a novel DNA mimic, peptide nucleic acid (PNA) in 1991, PNAs have attracted tremendous interest and have shown great promise as potential antisense drugs. They have been used extensively as tools for specific modulation of gene expression by targeting translation or transcription processes. This review discusses the present and future therapeutic potential of this class of compound as anti-HIV-1 drugs.

29 citations

Journal ArticleDOI
TL;DR: The cytotoxic effects of ritonavir involved the interplay of ER stress and mitochondria-mediated apoptosis, a unusual mechanism of drug-induced toxicity that expands the knowledge in understanding side effects caused by ritonvir.
Abstract: Endoplasmic reticulum (ER) stress is a growing concern for drug-induced toxicity which causes several side effects. Ritonavir, a potent HIV protease inhibitor, induces both ER and mitochondrial stress; however, the missing link between ER stress and mitochondrial damage has been unknown. In the present study, we have studied the sequential events that occur during ritonavir-induced cell cytotoxicity and elucidate the link between ER stress and mitochondrial damage. Cytotoxicity of ritonavir was calculated on different cells; Huh-7.5, 293T, HeLa, and Hepa RG cells using the MTT assay and also by measuring total protein content. Cellular stress response was evaluated by RT-PCR for stress marker genes. Entry of drug into the mitochondrial compartment was evaluated by HPLC. Mitochondria-mediated apoptosis was analyzed by western blotting. Ritonavir treatment initially triggered ER stress during the early hours of treatment. Consequently, the BAX was activated which permeabilized the mitochondrial outer membrane. Simultaneously, upon entry of the drug into the mitochondrial compartment, change in mitochondrial membrane potential was observed which led to the release of cytochrome c in the cytoplasm. Release of cytochrome c activated mitochondria-mediated apoptosis by the activation of caspase-9/7 and parp-1. The cytotoxic effects of ritonavir involved the interplay of ER stress and mitochondria-mediated apoptosis. This unusual mechanism of drug-induced toxicity expands our knowledge in understanding side effects caused by ritonavir.

25 citations

Journal ArticleDOI
23 Jun 2013-Nucleus
TL;DR: Transgenic plants of Tylophora indica obtained via somatic embryogenesis through genetic transformation by Agrobacterium rhizogenes have been maintained in vitro for over 6 years and the comparison of long term cultures and field grown normal and transformed plants on various morphological, biochemical and molecular characterisation described.
Abstract: Transgenic plants of Tylophora indica obtained via somatic embryogenesis through genetic transformation by Agrobacterium rhizogenes have been maintained in vitro for over 6 years and the comparison of long term cultures and field grown normal and transformed plants on various morphological, biochemical and molecular characterisation described. Ri-transformed plants were found to be morphologically stable after 6 years in axenic culture as well as after transfer to the field. Genetic stability for rolA, rolB, rolC and rolD genes were obtained in Ri-transformed plants prior to and after transfer to field. The chromosome number, 2n = 22 was maintained in all the transgenic plants. The Ri-transformed plants retained and expressed all the four rol genes after transfer to the field and were able to synthesise and accumulate tylophorine. Thus, the Ri-transformed plants were found to be stable for more than 6 years in vitro and after 1year of field transfer.

19 citations


Cited by
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Journal ArticleDOI
TL;DR: To efficiently deliver siRNAs to the target cells and tissues, many different siRNA bioconjugates were synthesized and characterized, and their gene silencing efficiencies were tested in vitro and in vivo.

359 citations

Journal ArticleDOI
TL;DR: TAT-conjugated NPs enhanced the CNS bioavailability of the encapsulated PI and maintained therapeutic drug levels in the brain for a sustained period that could be effective in reducing the viral load in the CNS, which acts as a reservoir for the replicating HIV-1 virus.

286 citations

Journal ArticleDOI
TL;DR: The results show that CPP–PNA conjugates of different types can inhibit Tat-dependent trans-activation in HeLa cells and have potential for development as antiviral agents.
Abstract: The trans-activation response (TAR) RNA stem–loop that occurs at the 5′ end of HIV RNA transcripts is an important antiviral target and is the site of interaction of the HIV-1 Tat protein together with host cellular factors. Oligonucleotides and their analogues targeted to TAR are potential antiviral candidates. We have investigated a range of cell penetrating peptide (CPP) conjugates of a 16mer peptide nucleic acid (PNA) analogue targeted to the apical stem–loop of TAR and show that disulfide-linked PNA conjugates of two types of CPP (Transportan or a novel chimeric peptide R6-Penetratin) exhibit dose-dependent inhibition of Tat-dependent trans-activation in a HeLa cell assay when incubated for 24 h. Activity is reached within 6 h if the lysosomotropic reagent chloroquine is co-administered. Fluorescein-labelled stably-linked conjugates of Tat, Transportan or Transportan TP10 with PNA were inactive when delivered alone, but attained trans-activation inhibition in the presence of chloroquine. Confocal microscopy showed that such fluorescently labelled CPP–PNA conjugates were sequestered in endosomal or membrane-bound compartments of HeLa cells, which varied in appearance depending on the CPP type. Co-administration of chloroquine was seen in some cases to release fluorescence from such compartments into the nucleus, but with different patterns depending on the CPP. The results show that CPP–PNA conjugates of different types can inhibit Tat-dependent trans-activation in HeLa cells and have potential for development as antiviral agents. Endosomal or membrane release is a major factor limiting nuclear delivery and trans-activation inhibition.

236 citations

Journal ArticleDOI
TL;DR: A comprehensive coverage of the enormous amount of published data was not possible, so emphasis has been put on strategies that have proven to be effective in animal models of important human diseases and on examples taken from the authors' own expertise.

219 citations