N-Butyldeoxynojirimycin is a broadly effective anti-HIV therapy significantly enhanced by targeted liposome delivery
Oxford Antiviral Drug Discovery Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, UK. AIDS (London, England)
(Impact Factor: 5.55).
11/2008; 22(15):1961-9. DOI: 10.1097/QAD.0b013e32830efd96
N-Butyldeoxynojirimycin (NB-DNJ), an inhibitor of HIV gp120 folding, was assessed as a broadly active therapy for the treatment of HIV/AIDS. Furthermore, to reduce the effective dose necessary for antiviral activity, NB-DNJ was encapsulated inside liposomes and targeted to HIV-infected cells.
Thirty-one primary isolates of HIV (including drug-resistant isolates) were cultured in peripheral blood mononuclear cells to quantify the effect of NB-DNJ on viral infectivity. pH-sensitive liposomes capable of mediating the intracellular delivery of NB-DNJ inside peripheral blood mononuclear cells were used to increase drug efficacy.
NB-DNJ decreased viral infectivity with a single round of treatment by an average of 80% in HIV-1-infected and 95% in HIV-2-infected cultures. Two rounds of treatment reduced viral infectivity to below detectable levels for all isolates tested, with a calculated IC50 of 282 and 211 micromol/l for HIV-1 and HIV-2, respectively. When encapsulated inside liposomes, NB-DNJ inhibited HIV-1 with final concentrations in the nmol/l range (IC50 = 4 nmol/l), a 100 000-fold enhancement in IC50 relative to free NB-DNJ. Targeting liposomes to the gp120/gp41 complex with a CD4 molecule conjugated to the outer bilayer increased drug/liposome uptake five-fold in HIV-infected cells compared with uninfected cells. NB-DNJ CD4 liposomes demonstrated additional antiviral effects, reducing viral secretion by 81% and effectively neutralizing free viral particles to prevent further infections.
The use of targeted liposomes encapsulating NB-DNJ provides an attractive therapeutic option against all clades of HIV, including drug-resistant isolates, in an attempt to prevent disease progression to AIDS.
Available from: PubMed Central
- "This is the first empirical evidence that incorporation of bryostatin-2 into nanoparticles may provide advantages over using drug alone. Consistent with the data presented here, previous studies of other LNP-drug preparations have also documented increased drug uptake in cells exposed to lipid-drug formulations compared with drug alone , . "
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ABSTRACT: Antiretroviral therapy is currently only capable of controlling HIV replication rather than completely eradicating virus from patients. This is due in part to the establishment of a latent virus reservoir in resting CD4+ T cells, which persists even in the presence of HAART. It is thought that forced activation of latently infected cells could induce virus production, allowing targeting of the cell by the immune response. A variety of molecules are able to stimulate HIV from latency. However no tested purging strategy has proven capable of eliminating the infection completely or preventing viral rebound if therapy is stopped. Hence novel latency activation approaches are required. Nanoparticles can offer several advantages over more traditional drug delivery methods, including improved drug solubility, stability, and the ability to simultaneously target multiple different molecules to particular cell or tissue types. Here we describe the development of a novel lipid nanoparticle with the protein kinase C activator bryostatin-2 incorporated (LNP-Bry). These particles can target and activate primary human CD4+ T-cells and stimulate latent virus production from human T-cell lines in vitro and from latently infected cells in a humanized mouse model ex vivo. This activation was synergistically enhanced by the HDAC inhibitor sodium butyrate. Furthermore, LNP-Bry can also be loaded with the protease inhibitor nelfinavir (LNP-Bry-Nel), producing a particle capable of both activating latent virus and inhibiting viral spread. Taken together these data demonstrate the ability of nanotechnological approaches to provide improved methods for activating latent HIV and provide key proof-of-principle experiments showing how novel delivery systems may enhance future HIV therapy.
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ABSTRACT: In this paper the cellular neural network (CNN) with ratio memory
(RM) is implemented in CMOS to recognize and classify the image
patterns. In the implemented CMOS CNN, the BJT-based combined
four-quadrant multiplier and two-quadrant divider with separated
magnitude and sign is used to implement the Hebbien learning function
and the ratio memory. Thus, the combined multiplier and divider and the
CNN have simple structure and large input/output signal range. The
pattern learning and recognition function of the 9×9 CNN with RM
is simulated by both Matlab software and HSPICE. It has been verified
that the CNN with RM has the advantages of more stored patterns for
processing and longer memory time with feature enhancement as compared
to the CNN without RM. Thus, the proposed CNN with RM has great
potential in the applications of neural associate memory for image
Available from: Stefana M Petrescu
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ABSTRACT: Few endocytosed ligands, including bacterial toxins and simian virus 40 (SV40) have been shown to reach the endoplasmic reticulum (ER) in mammalian cells. Using calcein and fluorescently labelled lactoferrin encapsulated in fusogenic liposomes we found that the cargo uses a microtubule-based pathway with ER delivery. Endocytic uptake of the lipid vesicles was cholesterol dependent in all cell lines tested, including the caveolin-1-deficient human hepatoma 7 cell line. The ligand was transported in non-caveosome organelles requiring acidic pH for maturation, but able to escape the lysosomal route. These organelles were not recycling endosomes either, as shown by the lack of co-localization with recycling transferrin. Co-localization with the ER-tracker, orange fluorescent protein with KDEL signal retention and cholera toxin in live microscopy revealed an ER distribution of the fluorescent ligand. Brefeldin A, which prevents Golgi-dependent retrograde trafficking, does not disrupt the cargo delivery to the ER. This new endocytic pathway making use of acidic endosome-like organelles is an alternative to the reported SV40 caveolae pathways. Exploiting a cellular route linking the cell surface to the ER, fusogenic liposomes may become efficient drug delivery vehicles for ER stress and diseases.
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