title: Paramagnetic particles carried by cell-penetrating peptide tracking of bone marrow mesenchymal stem cells, a research in vitro.
abstract: The ability to track the distribution and differentiation of stem cells by high-resolution imaging techniques would have significant clinical and research implications. In this study, a model cell-penetrating peptide was used to carry gadolinium particles for magnetic resonance imaging of the mesenchymal stem cells. The mesenchymal stem cells were isolated from rat bone marrow by Percoll and identified by osteogenic differentiation in vitro. The cell-penetrating peptides labeled with fluorescein-5-isothiocyanate and gadolinium were synthesized by a solid-phase peptide synthesis method and the relaxivity of cell-penetrating peptide-gadolinium paramagnetic conjugate on 400 MHz nuclear magnetic resonance was 5.7311 +/- 0.0122 m mol(-1) s(-1), higher than that of diethylenetriamine pentaacetic acid gadolinium (p < 0.05). Fluorescein imaging confirmed that this new peptide could internalize into the cytoplasm and nucleus. Gadolinium was efficiently internalized into mesenchymal stem cells by the peptide in a time- or concentration-dependent fashion, resulting in intercellular T1 relaxation enhancement, which was obviously detected by 1.5 T magnetic resonance imaging. Cytotoxicity assay and flow cytometric analysis showed the intercellular contrast medium incorporation did not affect cell viability and membrane potential gradient. The research in vitro suggests that the newly constructed peptides could be a vector for tracking mesenchymal stem cells.
authors.affiliation: Imaging Center, The 2nd Affliated Hospital of Medical School, Xi'An Jiao Tong University, Xi'An City ShaanXi Province, China.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: You-min
authors.initials: YM
authors.lastname: Guo
authors.forename: Qi-fei
authors.initials: QF
authors.lastname: Wu
authors.forename: Jun-le
authors.initials: JL
authors.lastname: Yang
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Si-cen
authors.initials: SC
authors.lastname: Wang
authors.forename: Xiao-juan
authors.initials: XJ
authors.lastname: Guo
authors.forename: Yong-qian
authors.initials: YQ
authors.lastname: Qiang
authors.forename: Xiao-yi
authors.initials: XY
authors.lastname: Duan
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002478:Cells, Cultured; D003287:Contrast Media; D019786:Gadolinium DTPA / Q000737:chemistry; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D010316:Particle Size; D010455:Peptides; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003287:Contrast Media; D010455:Peptides; D019786:Gadolinium DTPA