A preliminary study on the interaction between Asn-Gly-Arg (NGR)-modified multifunctional nanoparticles and vascular epithelial cells

Liu, Chunxi; Liu, Tingxian; Yu, Xiaoyue; Gu, Yizhu

In evaluating the interaction between TPIC and CD13, we found that TPIC could bind to CD13 (Fig. 5A, 4 1C) and enter HUVEC together with CD13 at 37 1C (Fig. 5A, 37 1C) . However, TPIC changed the distribution of CD13 on HUVEC, causing CD13 clustering. The cluster of CD13 was possibly because of the accumulation after interacting with NGR on the TPIC surface. This aggregation of receptors was a ubiquitous phenomenon in the process of receptor-mediated endocytosis, which further demonstrated that the The groups in the presence of TPIC but without inhibitor treatment as controls and their fluorescence intensities were expressed as 100%. The decreased fluorescence of other groups compared with control suggested the potential mechanism of internalization. uptake of TPIC in HUVEC was via CD13-mediated active targeting endocytosis. Moreover, CD13 and TPIC were not completely colocalized, and some separately entered the cells, which might be because CD13 needed to separate from the CD13-NGR complex and recycle to the cell surface to be used again. This type of receptor cycle was verified in the following endocytosis kinetic experiments (Fig. 7) .