Our research interests surround simian virus 40 (SV40), a small, non-pathogenic double-stranded DNA virus. Our research interest is to understand cellular processes at the molecular level and apply the knowledge for the development of medical applications.
BASIC BIOLOGICAL RESEARCH
The basic biological research encompasses investigations on SV40 cell entry and cellular signaling. Upon infection SV40 elicits multiple signaling in the host, which facilitate its endocytosis, intracellular trafficking and propagation. We specifically focus on signaling induced by the viral capsid proteins prior to nuclear entry of the viral genome and viral gene expression. We found that upon infection SV40 elicits complex signaling networks, including pro-apoptotic signaling and survival pathway. Intriguingly these two opposing pathways are robustly balanced, as the cells neither apoptose nor proliferate. Regulation of this balance is our major interest, presently under investigation.
p53 (Green) is activated in cells infected by SV40 immediately after the infection, as part of the host defense mechanism. Activation occurs, however, only in a subset of the infected cells. This cell-to-cell variability has clear consequences on the outcome of the infection. None of the cells with elevated p53 at the time of infection proceeded to express T-ag (red), arresting the viral life cycle and propagation, supporting a role for p53 in defending against the virus. However the p53-mediated host defense mechanism against SV40 is not facilitated by apoptosis nor via interferon-stimulated genes. Instead p53 binds to the viral DNA at the T-ag promoter region, prevents its transcriptional activation by Sp1, and halts the progress of the infection.
Prof. Galit Lahav, PhD, Chair, Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA
BASIC BIOPHYSICAL RESEARCH
We are interested in the assembly of the SV40 capsid in vivo, during viral propagation, and in vitro, in the test tube. We found that assembly in vitro requires a polymeric scaffold, and the size of the formed capsid depends on the size and nature of the scaffold, which may be DNA, RNA or another polymer. Empty virus nanoparticles may be formed by expressing the major viral capsid protein in insect cells.
We also study the properties of the virus, and empty nanoparticles, in response to changes in the external environment.
Empty SV40 nanoparticle
Wild type SV40
The images are shown at molecular resolution, based on Small Angle X-ray Scattering. The capsid shell is shown in light blue, the DNA double helix in dark blue and histone proteins in red. Lines represent backbones of molecules that form the structure, not including the atoms.
Prepared by Prof. Uri Raviv and his doctoral student Roi Asor.
Prof. Uri Raviv, PhD, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
Beginning with studies towards the development of SV40 as a gene therapy vector in the Eighties, we continued, in the Nineties, through developing a safe viral vector that would be assembled in vitro around plasmid DNA of choice. Experiments in animal models demonstrated that the empty capsids, without any enclosed DNA, function significantly better than the gene therapy vector containing the plasmid of choice! Since that discovery our studies are focused on the therapeutic properties of the empty capsids, SV40 nanoparticles (NPs). So far we focused on two severe diseases, that have no therapy except for mechanical support (and antibiotics when relevant) in intensive care units: acute kidney injury and sepsis. We found that the NPs significantly improved survival in pre-clinical models for both. The underlying mechanisms is through the activation (and suppression) of genes and pathways. Interestingly the genes and pathways activated for each of those diseases are widely different. Our recent sepsis study demonstrated that the pathways elicited by the NPs were associated with many biological functions, including immune response, anti-pathogenic pathways, regeneration, morphogenesis and homeostasis. Furthermore, the affected genes and pathways were modified with time, along the progress of the disease and recovery process. Significantly, when administered to control healthy rats, the NPs induced negligible changes in gene expression. Presently we continue to develop this reagent towards a therapeutic agent. We propose that the NPs acquired these fascinating properties during virus-host coevolution, selected for the “selfish goal” of the virus to propagate in a healthy host. In parallel we strive to understand the biological mechanism that facilitates this extraordinary property.
SV40 nanoparticles, produced from a single protein SV40 VP1, injected to septic rats, dramatically affect survival in comparison to vehicle injection to control rats. Transcript analyses of rat lung RNA reveals a wide scope of cellular and systemic functions that illuminate the therapeutic effect of the nanoparticles.
Dr. Arieh Eden, MD, Director, General Intensive Care Unit, Carmel, Lady Davis Medical Center, Haifa, Israel.
Relevant recent publications
Stanislav Kler, Joseph Che-Yen Wang, Mary Dhason, Ariella Oppenheim and Adam Zlotnick. 2013. Scaffold properties are a key determinant of the size and shape of self-assembled virus-derived particles. ACS chemical biology 8, 2753-2761. Link
Drayman, N., Glick, Y., Ben-Nun-Shaul, O., Zer, H., Zlotnick, A., Gerber, D., Schueler-Furman, O., Oppenheim, A. 2013. Pathogens use structural mimicry of native host ligands as a mechanism for host receptor engagement. Cell Host Microbe 14: 63-73. Link
Gadiel Saper, Stanislav Kler, Roi Asor, Ariella Oppenheim, Uri Raviv and Daniel Harries. 2013. Effect of capsid confinement on the chromatin organization of the SV40 minichromosome. Nucleic Acids Research 41:1569-1580. Link
Oren Kobiler, Nir Drayman, Veronika Butin-Israeli and Ariella Oppenheim. 2012. Virus strategies for passing the nuclear envelope barrier. Nucleus 3:6, 1–14. Link
Kler, S., Asor, R., Li, C., Ginsburg, A., Harries, D., Oppenheim, A., Zlotnick, A., Raviv, U. 2012. RNA rapidly assembles SV40 VP1 pentamers into T=1 nanoparticles without appreciable intermediate concentrations. J. Am. Chem. Soc, 134, 8823−8830. Link
Veronika Butin-Israeli, Orly Ben-nun-Shaul, Idit Kopatz, Stephen A . Adam, Takeshi Shimi, Robert D Goldman and Ariella Oppenheim. 2011. Simian Virus 40 Induces Lamin A/C Fluctuations And Nuclear Envelope Deformation During Cell Entry. Nucleus, 2(4): 320-330. Link
Veronika Butin-Israeli, Nir Drayman and Ariella Oppenheim. 2010. Simian virus 40 infection triggers balanced network that includes apoptotic, survival and stress pathways. J. Virol. 84:3431-3442. Link
Orly Ben-nun-Shaul, Hagit Bronfeld, Dan Reshef, Ora Schueler-Furman, Ariella Oppenheim. (2009). The SV40 Capsid Is Stabilized by a Conserved Pentapeptide Hinge of the Major Capsid Protein VP1. J. Mol. Biol. 386, 1382–1391. Link
Veronika Butin-Israeli, Dotan Uzi, Mahmoud Abd-El-Latif, Galina Pizov, Aryeh Eden, Yosef S. Haviv, and Ariella Oppenheim. 2008. DNA-free recombinant SV40 capsids protect mice from acute renal failure by inducing stress response, survival pathway and apoptotic arrest. PLoS ONE. Aug 20;3(8):e2998. Link
Luminita Eid, M.D., Zohar Bromberg, M.Sc., Mahmoud Abd EL-Latif, B.S., Evelyn Zeira, B.S, Ariella Oppenheim, Ph.D., Yoram G. Weiss, M.D. 2007. Simian Virus 40 Vectors for Pulmonary Gene Therapy. Respiratory Research, 8:74. Link