(137d) Regenerative Engineering of the Endothelial Cell Glycocalyx Using Nanomedicine

The long term goal of this project is to apply regenerative engineering to rebuild the endothelial cell (EC) surface sugar coat, the glycocalyx (GCX). The GCX lines and protects the blood vessel wall, interfaces with flowing blood and mediates mechanotransduction, plays an important role in vascular homeostasis, and in its absence causes EC de-differentiation and dysfunction [Ebong et al., Integr Biol (Camb) 6, 3, 2014] that promote atherosclerosis leading to cardiovascular disease. Our regenerative engineering goal is to reconstitute the GCX to treat atherosclerosis and cardiovascular disease. In a present study, we are using a nanoparticle-based approach to replace GCX components and to deliver drugs that stimulate their synthesis. Here, we report on foundational experiments in which we assess how EC-specific nanoparticle delivery is impacted by baseline GCX conditions. We exposed rat fat pad EC (RFPEC) with intact GCX to ultra-small PEGylated gold nanoparticles [Kumar et al., Transl Cancer Res 2, 4, 2013]. RFPEC with intact GCX did not exhibit any nanoparticle uptake. In contrast, some nanoparticles were retained by RFPEC with protein deficient and collapsed GCX, characteristic of certain disease conditions. A more substantial number of nanoparticles were retained by RFPEC with enzymatically degraded GCX heparan sulfate, the most abundant component of the GCX. In another case, after enzymatic heparan sulfate degradation, we induced GCX regeneration by adding heparan sulfate to the culture media for its incorporation into the GCX. HS regeneration resulted in restoring blockage of nanoparticle entry into RFPEC. This work indicates that the GCX integrity and composition influence nanoparticle uptake by EC. The observed passive targeting of nanoparticles to GCX-deficient EC is promising for future work on this project. We look forward to further developing our PEGylated gold and other nanoparticles to delivery replacement GCX components or drugs to induce EC to regenerate GCX. Funding: Northeastern University and IGERT Nanomedicine Science & Technology Program at Northeastern University (NSF/DGE-096843).