PhD candidate, Johns Hopkins University
I am engineering nanoparticles that enable non-viral delivery of genes to retinal cells
Many ophthalmological diseases are a result of erroneous gene expression in the retina, either through the absence of a gene or upregulation. In many cases the absence of a gene or the lack of one of two functional copies means that patients become blind over the course of their lifetime. Gene delivery has the potential to ameliorate or even cure these diseases but currently suffers from low efficacy that limits its application. I am working on developing non-viral, biodegradable polymeric nanoparticle for delivery of nucleic acids like DNA and RNA to retinal cells by engineering polymers that specifically enable these materials to reach different retinal cell populations. Working both in vitro with cells isolated from mouse pups and in vivo by injecting in mouse eyes, I have demonstrated that the nanoparticles I've engineered can deliver nucleic acids to retinal cells including photoreceptor rod and cone cells as well as retinal ganglion neurons and retinal pigment epithelial cells.
Moving forward, I am working to demonstrate the mechanism by which these nanoparticles enable delivery of nucleic acids to these cell types. This is particularly important for developing more effective nanoparticles in the future that demonstrate even greater efficacy. I hope to see this technology further developed with pre-clinical models that have the potential to be picked up by industrial collaborations and brought to the clinic through clinical trials.
Abstract: Biodegradable polymeric nanoparticles have the potential to be safer alternatives to viruses for gene delivery; however, their use has been limited by poor efficacy in vivo. In this work, we synthesize and characterize polymeric gene delivery nanoparticles and evaluate their efficacy for DNA delivery of herpes simplex virus type I thymidine kinase (HSVtk) combined with the prodrug ganciclovir (GCV) in a malignant glioma model. We investigated polymer structure for gene delivery in two rat glioma cell lines, 9L and F98, to discover nanoparticle formulations more effective than the leading commercial reagent Lipofectamine 2000. The lead polymer structure, poly(1,4-butanediol diacrylate-co-4-amino-1-butanol) end-modified with 1-(3-aminopropyl)-4-methylpiperazine, is a poly(β-amino ester) (PBAE) and formed nanoparticles with HSVtk DNA that were 138 ± 4 nm in size and 13 ± 1 mV in zeta potential. These nanoparticles containing HSVtk DNA showed 100% cancer cell killing in vitro in the two glioma cell lines when combined with GCV exposure, while control nanoparticles encoding GFP maintained robust cell viability. For in vivo evaluation, tumor-bearing rats were treated with PBAE/HSVtk infusion via convection-enhanced delivery (CED) in combination with systemic administration of GCV. These treated animals showed a significant benefit in survival (p = 0.0012 vs control). Moreover, following a single CED infusion, labeled PBAE nanoparticles spread completely throughout the tumor. This study highlights a nanomedicine approach that is highly promising for the treatment of malignant glioma.
Pub.: 03 Feb '15, Pinned: 28 Jun '17