A. James Clark School of Engineering
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Investigation of Vesicular-Mediated Transport of Intercellular Adhesion Molecule-1-Targeted Carriers for Treatment of Lysosomal Storage Disorders(2017) Manthe, Rachel Lee; Muro, Silvia; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Numerous cellular processes and therapeutic interventions rely on vesicular-mediated endocytosis to gain entry into cells and sub-cellular compartments, as well as for transcellular transport across biological barriers such as found at the blood-brain interface. Yet, endocytic behavior can be altered in disease, representing an additional hurdle in the design of effective therapeutic strategies. Lysosomal storage disorders (LSDs), characterized by lysosomal accumulation of undigested substrates as a result of deficient enzymatic activity, illustrate this paradigm. Currently, intravenous infusion of recombinant lysosomal enzymes to replace those deficient is the standard clinical approach for these disorders. However, clathrin-mediated endocytosis utilized by replacement enzymes for cellular uptake and lysosomal trafficking is altered, thereby impacting treatment efficacy as recently demonstrated in acid sphingomyelinase-deficient type A Niemann-Pick disease (NPD). Therefore, alternative means to bypass defunct routes is warranted. Therapeutic delivery via polymer nanocarriers targeting intercellular adhesion molecule-1 (anti-ICAM NCs), a cell-surface molecule overexpressed in endothelial and subjacent tissue cells during inflammation, such as in LSDs, represents a viable option since it permits uptake, intra- and transcellular transport via a unique endocytic route called the cell adhesion molecule (CAM) pathway. In this dissertation, cell culture and animal models were used to examine the (1) endocytic activity of the CAM pathway and other clathrin-independent routes in type A NPD, (2) role of targeting valency (i.e., density of ICAM-1-targeting molecules on the NC surface) in regulating the CAM pathway, and (3) effects induced via engagement of ICAM-1 on cells by anti-ICAM NCs. The results herein demonstrate the CAM pathway is more active in diseased cells compared to other classical endocytic pathways, making it the most amenable route for therapeutic enzyme replacement. Further, modulating targeting valency of NCs optimized this strategy for enhanced enzyme delivery to the brain, a target organ for type A NPD. Lastly, anti-ICAM NCs attenuated endothelial release of soluble ICAM-1, an inflammatory regulator, representing a secondary benefit of this system. Overall, this work validates utility of anti-ICAM NCs for enzyme replacement to treat NPD and likely other LSDs, and provides insight into biological processes and design parameters that influence the therapeutic efficacy of targeted drug carriers.Item Targeting Intercellular Adhesion Molecule-1 to Enhance Delivery of Therapeutic Enzymes for Treatment of Lysosomal Storage Diseases(2014) Hsu, Janet; Muro, Silvia; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Lysosomal storage diseases (LSDs) are a group of more than 40 genetically inherited diseases that result from dysfunction of specific proteins, often an enzyme, located in lysosomes within cells which leads to abnormal lysosomal accumulation of specific macromolecules. As a result, cell malfunction occurs and escalates into multi-tissue and multi-organ failures, often resulting in premature death. For several early onset LSDs, the central nervous system (CNS) is also affected and manifests fatal neuropathic and/or neurodegenerative symptoms. Within the last two decades, treatment for selective LSDs has become clinically available. Specifically, enzyme replacement therapy (ERT) by intravenous injection of recombinant enzymes holds relevant promise. Yet current ERT results in suboptimal enzyme biodistribution to many target organs, including the peripheral organs and also the CNS. Delivery to the CNS is particularly impeded due to the tight blood-brain barrier (BBB) that strictly regulates passage between the circulation system and the brain tissue. We explored the use of targeted drug delivery systems to address this issue. Specifically, we focused on targeting intercellular adhesion molecule-1 (ICAM-1), a cell surface glycoprotein that is upregulated under pathological conditions, including LSDs. In this dissertation, using in vitro, cell culture, and in vivo techniques, we examined whether ICAM-1-targeted polymer nanocarriers: (1) enhance binding, uptake, and lysosomal delivery of different enzymes in cells, (2) provide targeting and transport across endothelial and subendthelial cells of the BBB, and (3) improve accumulation of lysosomal enzymes to peripheral organs and the brain. Results suggest that after intravenous injection of enzyme coupled to ICAM-1-targeted nanocarriers, ICAM-1 targeting shift these enzymes from the circulation to tissues, enhancing enzyme accumulation over non-targeted counterparts both in peripheral organs and the brain. This could be modulated by varying parameters such as the density of targeting antibodies on the carrier coat or the carrier bulk concentration. Also, ICAM-1-targeted nanocarriers were transported across BBB models followed by uptake and lysosomal transport to neuron-like cells. ICAM-1-targeted nanocarriers preferentially bound to diseased cells and were internalized and trafficked to lysosomes, resulting in degradation of the accumulated substrate. Therefore, overall, ICAM-1-targeting shows promise in improving ERT for LSD treatment.