A proteoliposome containing apolipoprotein A-I mutant (V156K) enhances rapid tumor regression activity of human origin oncolytic adenovirus in tumor-bearing zebrafish and mice

Modeling oncolytic virus dynamics in the tumor microenvironment using zebrafish

We have adapted a zebrafish (Danio rerio) tumor xenograft model for use in the study of oncolytic virotherapy. Following implantation of mammalian cancer cells into the perivitelline space of developing zebrafish embryos, both local and intravenous oncolytic virus treatments produce a tumor-specific infection with measurable antitumor effects. Tumor cells are injected at 48 h post fertilization, with oncolytic virus treatment then being administered 24 h later to allow for an initial period of tumor development and angiogenesis. Confocal fluorescent imaging is used to quantify dynamics within the tumor environment. The natural translucency of zebrafish at the embryo stage, coupled with the availability of strains with fluorescent immune and endothelial cell reporter lines, gives the model broad potential to allow for real time, in vivo investigation of important events within tumors throughout the course of virotherapy. Zebrafish xenografts offer a system with biologic fidelity to processes in human cancer development that influence oncolytic virus efficacy, and to our knowledge this is the first demonstration of the model's use in the context of virotherapy. Compared with other models, our protocol offers a powerful, inexpensive approach to evaluating novel oncolytic viruses and oncolytic virus-based combination therapies, with potential application to investigating the impacts of virotherapy on immune response, tumor vasculature, and metastatic disease.

Susceptibility of Zebrafish to Vesicular Stomatitis Virus Infection

The zebrafish, Danio rerio, has become recognized as a valuable model for infectious diseases. Here we evaluated the susceptibility of zebrafish to be infected with the mammalian vesicular stomatitis virus (VSV). Both zebrafish cells and embryos were highly susceptible to VSV infection. Mortalities exceeded 80% in infected embryos and were preceded by the invasion of the central nervous system by VSV. Live imaging of the infection with GFP-VSV as well as virus titration from infected fish confirmed the viral replication. Immunohistochemical analysis of embryonic fish provided evidence of viral antigens as well as of the apoptosis marker caspase-3 in the brain, eye, liver, pronephros, and skeletal muscle. So far, this is the first report describing the susceptibility of zebrafish to the mammalian virus VSV.

Molecular Characterization and Growth Association of Two Apolipoprotein A-Ib Genes in Common Carp (Cyprinus carpio)

Apolipoprotein A-I (ApoA-I) is functionally involved in the transportation and metabolism of lipids in vertebrates. In this study, two isoforms of apoA-Ib in common carp (Cyprinus carpio L.) were characterized. Sequence comparison and phylogenetic analysis showed that C. carpio ApoA-Ib is relatively conserved within cyprinid fishes. During embryonic development, C. carpioapoA-Ib was first expressed at the stage of multi-cells, and the highest mRNA level was observed at the stage of optic vesicle. A ubiquitous expression pattern was detected in various tissues with extreme predominance in the liver. Significantly different expression levels were observed between light and heavy body weight groups and also in the compensatory growth test. Seventeen and eight single-nucleotide polymorphisms (SNPs) were identified in matured mRNA of the C. carpioapoA-Ib.1 and apoA-Ib.2, respectively. Two of these SNPs (apoA-Ib.2-g.183A>T and apoA-Ib.2-g.1753C>T) were significantly associated with body weight and body length in two populations of common carp. These results indicate that apoA-Ib may play an important role in the modulation of growth and development in common carp.

Redirecting adenovirus tropism by genetic, chemical, and mechanical modification of the adenovirus surface for cancer gene therapy

INTRODUCTION

Despite remarkable advancements, clinical evaluations of adenovirus (Ad)-mediated cancer gene therapies have highlighted the need for improved delivery and targeting.

AREA COVERED

Genetic modification of Ad capsid proteins has been extensively attempted. Although genetic modification enhances the therapeutic potential of Ad, it is difficult to successfully incorporate extraneous moieties into the capsid and the engineering process is laborious. Recently, chemical modification of the Ad surface with nanomaterials and targeting moieties has been found to enhance Ad internalization into the target by both passive and active mechanisms. Alternatively, external stimulus-mediated targeting can result in selective accumulation of Ad in the tumor and prevent dissemination of Ad into surrounding nontarget tissues. In the present review, we discuss various genetic, chemical, and mechanical engineering strategies for overcoming the challenges that hinder the therapeutic efficacy of Ad-based approaches.

EXPERT OPINION

Surface modification of Ad by genetic, chemical, or mechanical engineering strategies enables Ad to overcome the shortcomings of conventional Ad and enhances delivery efficiency through distinct and unique mechanisms that unmodified Ad cannot mimic. However, although the therapeutic potential of Ad-mediated gene therapy has been enhanced by various surface modification strategies, each strategy still possesses innate limitations that must be addressed, requiring innovative ideas and designs.

Zebrafish: modeling for herpes simplex virus infections

For many years, zebrafish have been the prototypical model for studies in developmental biology. In recent years, zebrafish has emerged as a powerful model system to study infectious diseases, including viral infections. Experiments conducted with herpes simplex virus type-1 in adult zebrafish or in embryo models are encouraging as they establish proof of concept with viral-host tropism and possible screening of antiviral compounds. In addition, the presence of human homologs of viral entry receptors in zebrafish such as 3-O sulfated heparan sulfate, nectins, and tumor necrosis factor receptor superfamily member 14-like receptor bring strong rationale for virologists to test their in vivo significance in viral entry in a zebrafish model and compare the structure-function basis of virus zebrafish receptor interaction for viral entry. On the other end, a zebrafish model is already being used for studying inflammation and angiogenesis, with or without genetic manipulations, and therefore can be exploited to study viral infection-associated pathologies. The major advantage with zebrafish is low cost, easy breeding and maintenance, rapid lifecycle, and a transparent nature, which allows visualizing dissemination of fluorescently labeled virus infection in real time either at a localized region or the whole body. Further, the availability of multiple transgenic lines that express fluorescently tagged immune cells for in vivo imaging of virus infected animals is extremely attractive. In addition, a fully developed immune system and potential for receptor-specific knockouts further advocate the use of zebrafish as a new tool to study viral infections. In this review, we focus on expanding the potential of zebrafish model system in understanding human infectious diseases and future benefits.

Bovine apolipoprotein (apo)A-I displays more enhanced antioxidant and anti-atherosclerotic activity in lipid-free and lipid-bound states than human and porcine apoA-I

Apolipoprotein A-I (apoA-I) is a major component of high-density lipoprotein (HDL), which displays anti-atherosclerotic activity in plasma. In the current study, we compared the functional and structural characteristics of human, bovine and porcine apoA-I as regards their antioxidant ability and protein stability. In the lipid-free state, the immunoreactivity of bovine and porcine apoA-I differed from that of human apoA-I and bovine and porcine apoA-I exhibited greater resistance to denaturation induced by urea treatment. Bovine apoA-I showed the weakest binding ability of dimyristoyl phosphatidylcholine; however, bovine apoA-I formed slightly larger reconstituted HDL (rHDL) particles with palmitoyl oleoyl phosphatidylcholine, with a higher number of apoA-I-containing particles. Bovine and porcine apoA-I comprised of pentameric structures, whereas human apoA-I in the rHDL state consisted of trimeric structures. Although apoA-I from all three species showed a similar content of α-helicity in the lipid-free state (approximately 53%), bovine apoA-I showed a lower α-helicity content (approximately 66%) compared with human apoA-I (approximately 74%) in the rHDL state. Bovine apoA-I was more resistant to denaturation and glycation upon treatment with urea and fructose, respectively. Furthermore, bovine apoA-I showed a greater inhibition of cupric ion-mediated low-density lipoprotein (LDL) oxidation and uptake of acetylated LDL by macrophages compared with human or porcine apoA-I in the lipid-free and lipid-bound states. In conclusion, bovine apoA-I has unique functional properties in the lipid-free and lipid-bound states, and displays significantly enhanced anti-atherosclerotic activity.