Abstract 3921: Single Wall Carbon Nanotubes (SWNT)-COOH Mediate Mesenchymal Stem Cell Proliferation and Differentiation
Background: The combination of the exquisite mechanical and electric properties of SWNT-COOH with mesenchymal stem cells (MSC) provides a promising three-dimensional microenvironment for facilitating the use of MSC in tissue engineering. However, little is known about the impact of SWNT-COOH on MSC proliferation, differentiation and survival.
Methods: Cell proliferation was measured by MTS assay, and differentiation of MSCs with and without SWNT-COOH in the presence of 5-azacytidine (5-aza) was analyzed using specific cardiac markers. Cell survival was studied by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. In addition, we traced the intracellular movement of SWNT on cellular ultra structure. The expression of Akt, Bcl-2, Bax, and cleaved caspase-9 was detected using Western blot analysis.
Results: Proliferation of MSCs was significantly enhanced in the group with SWCNT-COOH present as compared to the vehicle control (p<0.05). The optimal concentration was found to be between 0.0015 and 0.0075 mg/ml (Fig. 1A⇓). GATA4, an early marker of cardiac cell lineages, was observed when co-cultured MSC with SWCNT-COOH in the presence of 5-aza (p<0.05 vs. vehicle control) (Fig. 1B⇓). SWNT-COOH promoted Akt phosphorylation in MSC and wortmannin (100 nM), an inhibitor of phosphatidylinositol 3-kinase, significantly suppressed BMS-induced Akt phosphorylation (Fig. 1C⇓). In addition, the intracellular movement of SWNT-COOH and effects on cellular ultra structures were assessed.
Conclusion: SWNT-COOH promoted MSC proliferation, differentiation and enhanced cell survival via PI-3K/Akt signaling pathway.