Mechanisms For Cellular Internalization Of Tat And Tat-nanoparticles Conjugates

Cell penetrating Peptide (CPP), derived from the Tat protein sequence of human immune deficiency virus type-1 (HIV-1), is one of the most promising tools for its membrane transduction potential and efficient delivery cargoes, including nucleic acids, polypeptides, and nanoparticles into cells. However, the cellular uptake mechanism of Tat peptide and its couples is not very clear by now.This thesis is to clearify the mechanism of penetration, and cargo delivery of Tat peptide into both rabbit bone marrow stem cells (BMSCs) and Hela cells. The main results of this thesis are as follows:1) BMSCs were isolated via density gradient centrifugation, and could be differentiated into osteoblasts in vitro.2) Tat peptide could be internalized into BMSCs and Hela cells via a lipid raft-mediated endocytosis pathway efficiently at 37℃, where it can reach includes the cytoplasm and vicinity of the nucleus. Internalization of Tat peptide into cells is depended on concentration, serum, temperature and ATP.3) Tat mediated gelatin-silica nanoparticles were internalized into BMSCs via a lipid raft-mediated endocytosis pathway, whearas via a recepter-dependent and lipid raft-dependent endocytosis pathway into Hela cells. Its internalization was inhibited at 4℃and deletion of ATP.4) Tat mediated Au-Au₂S nanoparticles were internalized into BMSCs via a lipid raft-dependent and recepter-depentdent endocytosis pathway, whearas via a clathrin mediated endocytosis pathway into Hela cells. Its internalization was inhibited at 4℃and deletion of ATP.