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

Previously developed Asn-Gly-Arg (NGR) peptide-modified multifunctional poly(ethyleneimine)-poly(ethylene glycol) (PEI-PEG)-based nanoparticles (TPIC) have been considered to be promising carriers for the co-delivery of DNA and doxorubicin (DOX). As a continued effort, the aim of the present study was to further evaluate the interaction between TPIC and human umbilical vein endothelial cells (HUVEC) to better understand the cellular entry mechanism. In the present investigation, experiments relevant to co-localization, endocytosis inhibitors and factors influencing the internalization were performed. Without any treatment, there was no co-localization between aminopeptidase N/CD13 (APN/CD13) and caveolin 1 (CAV1). However, co-localization between CD13 and CAV1 was observed when cells were incubated with an anti-CD13 antibody or TPIC. As compared with antibody treatment, TPIC accelerated the speed and enhanced the degree of co-localization. TPIC entered HUVEC not only together with CD13 but also together with CAV1. However, this internalization was not dependent on the enzyme activity of CD13 but could be inhibited by methyl--eyclodextfin (MCD), further identifying the involvement of caveolae-mediated endocytosis (CvME). This conclusion was also verified by endocytosis inhibitor experiments.

Value of Heparin Blocking Attachment of Respiratory Syncytial Virus to Human Airway Epithelial Cells / 实用儿科临床杂志

Objective To investigate the mechanisms of attachment of respiratory syncytial virus(RSV) to human airway epithelial cells.Methods Attachment of RSV to CFBE was quantitatively assessed by flow cytometry.Various polyclonal and monoclonal antibodies to RSV and heparin were pre-incubated with RSV.The blocking effects of these antibodies and heparin on attachment were evaluated.Results CFBE cells reduced capacity being bound by RSV.All the antibodies used were failed to block attachment of RSV on CFBE,whereas heparin blocked RSV attachment in a dose-response manner and the blokade by heparin was almost complete at the concentration of 0.4 mg/L.Conclusions Flow cytometry provides direct evaluation of attachment without growth of virus.Heparin-like molecules on cell surface of CFBE appears to be involved in attachment between RSV and human epithelial cells.