Date of Award

Spring 2022

Document Type


Degree Name

Doctor of Philosophy (PhD)


Molecular Biophysics and Biochemistry

First Advisor

Saltzman, W. Mark


The human endothelium extends throughout nearly all tissues in the body, and has an estimated total surface area of up to seven thousand square meters [1]. This expansive monolayer of endothelial cells (ECs) serves as the interface between materials circulating in the bloodstream and the internal tissues of the body. Even in its quiescent state, the endothelium is actively signaling and reacting in order to support the basic functions of the vascular system – transporting oxygen, nutrients, and waste. A closer look reveals that the cells that make up this endothelial lining are diverse in their phenotypes and functions, dependent on the organ or tissue in which they reside. When activated under inflammatory conditions or in other disease states, endothelial cells further differentiate themselves through expression of surface antigens. Being a large, easily accessible surface that interfaces with almost all other tissues in the body, and consisting of distinctly identifiable subcategories as well as some universal characteristics, the endothelium is an attractive therapeutic target. Of particular interest in this dissertation is applying gene therapies to treat or prevent inflammation.We describe a polymeric delivery system for nucleic acids that can be modulated by exchanging polymer end-groups and conjugating cell surface targeting molecules to the delivery vehicle. We show that conjugating EC targeting antibodies to the surface of a cationic poly(amine-co-ester) (PACE) nucleic acid delivery vehicle enhances its transfection efficiency in cultured human ECs. This can enable delivery of gene therapies to ECs, either in vitro as cellular components of an engineered vascular graft, ex vivo in donated human organs for transplantation, or for targeting the endothelium in vivo. In the work presented here we apply the EC-targeted polymeric delivery vehicle to deliver siRNA against IL-15, a cytokine involved the activation of T cells during acute inflammation. Our work with transplant-declined human organs motivated the development of a new digital pathology tool for color-based quantification of histologic specimens, which we have applied to quantify vascular assembly in engineered grafts as well as vascular pathologies in human and animal tissue samples. We demonstrate the benefits of an automated program for color-based detection of pathological features in histologic specimens, in particular in a setting in which large numbers of images are generated. We propose further investigations into the antibody-targeted PACE polyplex delivery platform including a broader exploration of targeting in different cell types in vitro and in vivo. The work described in this dissertation aims to advance the therapeutic potential of targeted nanocarriers for treating pathologies in the endothelium.