Vascular pathology, imaging, atherosclerosis, restenosis, gene therapy, adenovirus, adeno-associated virus, NO, NO synthase, ROS, nanotechnology
In general terms my main research interests are in the field of vascular gene therapy.
My postdoctoral studies explored a strategy of local arterial wall delivery of adenoviral vectors immobilized on the stent surface. Using monomolecular layer of metal-coordinating polymer as a bridging moiety we were able to achieve covalent attachment of adenoviral affinity adapters (either anti-adenoviral antibody, or D1 domain of the native Cocxackie-Adenovirus Receptor; CAR) to metal surfaces. Subsequent reversible vector tethering allows for highly efficient spatially restricted gene transfer in vitro and has shown promising results in rat and pig angioplasty/stenting model, demonstrating significant reporter gene activity in all layers of stented arterial segment.
Lately we investigated an alternative strategy of direct covalent vector tethering to the metal surface via hydrolysable cross-linker, which might be advantageous since it seems to be more robust and versatile in terms of vector type. Presently we are conducting large animal study with therapeutic adenoviral vector (Ad-eNOS) to assess antirestenotic efficacy of gene delivery stents in the pig angioplasty/stenting model.
Additionally we have recently developed a novel strategy for localized delivery of viral and non-viral gene therapy vectors co-formulated with magnetic nanoparticles to stented arteries using uniform magnetic field-induced targeting. The latter approach allows as well a targeted delivery of cells transduced with the abovementioned vectors to stented arteries, facilitating the process of reendothelialization.
Gene delivery from biodegradable stents
Recent advent of drug-eluting metal stents has significantly improved short-term and intermediate outcomes in patients undergoing coronary stenting. However, animal and clinical data shows that long-term efficacy of this new treatment is questionable. Most experts in the field agree that a presence of a stent per se perpetuate chronic foreign body response leading to eventual revascularization failure. To this end, attempts have been made to formulate stent fabricated from biodegradable polymers. Polyesters (e.g. polylactic acid; PLA) possess mechanical properties comparable to metals and thus represent uppermost interest. Fabrication of PLA stents is compatible with either bulk immobilization, or surface tethering of adenoviral vectors via cleavable cross-linker developed in our lab. Therapeutic gene constructs delivered from degradable stent platform might address excessive smooth muscle proliferation, migration and synthetic activity or/and accelerate stent decomposition.
Vascular homing of genetically modified macrophages
Cells of monocyte/macrophage lineage play central role in the initiation of atherosclerotic lesions due to selective homing in the areas of dysfunctional endothelium and vascular inflammation. Likewise, macrophages accumulate in the injured/stented arteries and induce smooth muscle cell activation owing to the secretion of PDGF, bFGF and several other growth factors and cytokines. Strategies directed on temporary elimination or functional impairment of macrophages have been shown to reduce restenosis in animal models.
I would like to exploit intrinsic vasculature homing traits of monocytes to achieve selective cell/gene delivery to evolving atherosclerotic and restenotic lesions. The suggested approach is based on stable genetic modification of autologous monocytes ex vivo with subsequent systemic administration in hypercholesterolemic transgenic Apo E-deficient mice and in rats with injury-induced restenosis. A list of possible genetic modification of monocytes comprises the loss of function interventions inhibiting the synthesis/secretion of growth factors or downregulation of NFkB and TNFa to block inflammatory cascade, or the gain of function gene therapy emphasizing secreted antiproliferative gene products.
Surface modification of adenoviral vectors
Cell types constituting vasculature has relatively low susceptibility to adenoviral infection, primarily because of limited CAR expression. Moreover, duration of transgene expression in the arterial wall does not usually exceed several weeks due to marked immune response elicited by adenoviruses. To address these two problems I recently examined a strategy of adenoviral vector surface modification by polyallylamine-based polymer derivatized with photo-reactive (benzophenone) and thiol-reactive (pyridyl-dithio) groups. Upon 30 sec UV irradiation of the virus/polymer mixture activated benzophenone groups covalently tether polymer to the capsid proteins of virus vector. Thiol-reactive moieties of the virus-conjugated polymer were further derivatized with protein transduction domain peptides, TAT and Antp. The latter were shown to mediate facilitated cellular internalization of liposomes and viruses notwithstanding of specific receptor repertoire. Our first in vitro experiments with TAT/Antp-modified adenoviral vectors have shown more than 100-fold increase in reporter gene transduction in comparison with non-modified vector in the cell line of endothelial origin.
We also predict enhanced in vivo activity of modified vector since surface-bound polymer fibers should create protective layer hindering virus inactivation by neutralizing antibodies, as was previously shown for polyethylene glycol-modified adenovirus.
Lastly, the suggested strategy will allow us to co-modify vector surface with other relevant targeting ligands thus increasing tissue residence of the adenovector and its specificity for the activated endothelium and smooth muscle cells.
- Research Assistant Professor of Pediatrics at University of Pennsylvania School of Medicine (2005– present)
- PhD, Pharmaceutical Science, Hebrew University of Jerusalem: Jerusalem, Israel (2000)
- MD, University of Saratov; Saratov, Russia (1987)
- Fishbein Ilia, Forbes Scott P, Chorny Michael, Connolly Jeanne M, Adamo Richard F, Corrales Ricardo A, Alferiev Ivan S, Levy Robert J. Adenoviral vector tethering to metal surfaces via hydrolyzable cross-linkers for the modulation of vector release and transduction.. Biomaterials. Vol 34(28) . 2013 Sep:6938-48.
- Forbes, Scott P., Alferiev, Ivan S., Chorny, Michael, Adamo, Richard F., Levy, Robert J., Fishbein, Ilia. Modulation of NO and ROS production by AdiNOS transduced vascular cells through supplementation with L-Arg and BH4: Implications for gene therapy of restenosis. Atherosclerosis. Vol 230(1) . 2013 September:23-32.
- Chorny Michael, Fishbein Ilia, Tengood Jillian E, Adamo Richard F, Alferiev Ivan S, Levy Robert J. Site-specific gene delivery to stented arteries using magnetically guided zinc oleate-based nanoparticles loaded with adenoviral vectors.. FASEB journal. Vol 27(6) . 2013 Jun:2198-206.
- Ma Guilei, Wang Yong, Fishbein Ilia, Yu Mei, Zhang Linhua, Alferiev Ivan S, Yang Jing, Song Cunxian, Levy Robert J. Anchoring of self-assembled plasmid DNA/anti-DNA antibody/cationic lipid micelles on bisphosphonate-modified stent for cardiovascular gene delivery.. International J Nanomedicine. Vol 8. 2013 March:1029-35.
- Chorny Michael, Alferiev Ivan S, Fishbein Ilia, Tengood Jillian E, Folchman-Wagner Zoë, Forbes Scott P, Levy Robert J. Formulation and in vitro characterization of composite biodegradable magnetic nanoparticles for magnetically guided cell delivery.. Pharmaceutical research. Vol 29(5) . 2012 May:1232-41.
- Chorny Michael, Fishbein Ilia, Yellen Benjamin B, Alferiev Ivan S, Bakay Marina, Ganta Srinivas, Adamo Richard, Amiji Mansoor, Friedman Gary, Levy Robert J. Targeting stents with local delivery of paclitaxel-loaded magnetic nanoparticles using uniform fields.. Proceedings of the National Academy of Sciences of the United States of America. Vol 107(18) . 2010 May:8346-51.
- Chorny Michael, Fishbein Ilia, Alferiev Ivan, Levy Robert J. Magnetically responsive biodegradable nanoparticles enhance adenoviral gene transfer in cultured smooth muscle and endothelial cells.. Molecular pharmaceutics. Vol 6(5) . 2009 Sep-Oct:1380-7.
- Fishbein Ilia, Alferiev Ivan, Bakay Marina, Stachelek Stanley J, Sobolewski Peter, Lai Meizan, Choi Hoon, Chen I-W, Levy Robert J. Local delivery of gene vectors from bare-metal stents by use of a biodegradable synthetic complex inhibits in-stent restenosis in rat carotid arteries.. Circulation. Vol 117(16) . 2008 Apr:2096-103.