Novel carbon nanodots for modulation of OxLDL mediated inflammation and inhibition of atherosclerosis

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PROJECT SUMMARY/ABSTRACT The long-term goal of this research is to develop carbon nanodots as the foundation of a new approach to "nanopharmacology" for the treatment of cardiovascular diseases. Vascular inflammation and its subsequent endothelial dysfunction play an important role in the development and progression of atherosclerotic vascular disease. As a known biomarker of inflammation, oxidized low-density lipoprotein (OxLDL) induces inflammatory gene expression, and monocyte extravasation that leads to atherosclerotic development. A search for a new approach to the treatment of inflammation is of great clinical significance for patients with atherosclerosis. Nanomaterials are important to the development of nanotechnology and carbon nanodots (C-dots) are fascinating newcomers with sizes below 10 nm and have emerged in the past decade to the world of nanoparticles. Due to its variability on surface modifications, green synthesis methods, unique luminescence properties, and excellent biocompatibility, C-dots have drawn considerable attention. The results of our cell viability studies have shown that C-dots have low cytotoxicity, which complied with earlier studies. Based on our more recent studies, we found C-dots could reduce Ox-LDL that are related to monocyte adhesion in endothelial cells, thus demonstrating the anti-inflammatory effects of C-dots. On the other hand, the overproduction of reactive oxygen species (ROS) is known to cause endothelial dysfunction. By using electron paramagnetic resonance (EPR) spectroscopy, the most sensitive and specific technique for ROS detection, our studies have also showed that C-dots could directly lower the in vitro levels of superoxide and hydroxyl radicals. These results together suggest C-dots hold a great potential to become a new avenue of "nanopharmacology" for more effective treatment of inflammatory disorders such as atherosclerosis. Extensive studies demonstrated that the activation of NF-κB is essential for the transcriptional regulation of inflammatory response. We, therefore, hypothesize that the antioxidant properties of C-dots can suppress OxLDL-induced adhesion of monocytes to endothelial cells by inhibiting NF-κB signaling that subsequently regulates the expression of chemokine and adhesion molecules. The specific aims of this R15 proposal are: 1a) to determine whether C-dots inhibit the expression of OxLDL-induced adhesion molecule and vascular inflammatory markers; 1b) to investigate whether the NF-κB signaling in endothelial cells is involved in the anti-inflammatory mechanism(s) of C-dots; and 2) to carry out a bio-distribution and safety studies of C-dots in C57BL/6 mice, and the protective effects of C-dots on vascular oxidative stress, inflammation, and atherosclerosis in low–density lipoprotein receptor (LDLr−/−) knockout mice. The proposed studies will also provide valuable training opportunities for undergraduate students interested in basic science research. Fulfillment of this research project is expected to provide new information on the potential applications of novel carbon nanodots to modulate OxLDL mediated inflammation and atherosclerosis.