In vitro and in vivo modulation of Hematopoietic Stem Cell (HSCs) differentiation into T and B cells by poly dispersed acid-functionalized single-walled carbon nanotubes (AF-SWCNTs)

Abstract

Abstract Background AF-SWCNTs are known to have significant effect on the immune function. There is not much information available on the effect of carbon nanotubes (CNTs) on the differentiation of the HSCs. In the present study we have focused on studying the modulatory effects of AF-SWCNTs on the differentiation of HSCs into T & B cells. Methods Single-walled CNTs were acid-functionalized by treating with concentrated sulfuric & nitric acid; thus, tagged with Alexa Fluor 633 to get fluorescent AF-SWCNTs (FAF-SWCNTs). To study internalization, magnetic beads enriched C57bl/6 mouse bone marrow (BM) HSCs (Lin− Sca1+cKit+) were incubated with FAF-SWCNTs & studied using flow cytometry & confocal microscopy. HSCs were cultured with a cocktail of cytokines to induce differentiation to T & B cells, in (+/−) AF-SWCNTs & monitored by live cell imaging. For in vivo ontogenesis study, mice were lethally irradiated (gamma irradiation) & reconstituted using syngeneic BM cells pretreated (+/−) AF-SWCNTs. At different time points, appearance of T & B cells in the spleen was monitored. Results Our results indicate that HSCs internalized significant amounts of FAF-SWCNTs in vitro that remained essentially localized in cytoplasm. Differentiation of cytokines stimulated HSCs to T & B cell was significantly suppressed by AF-SWCNTs. Results of our in vivo experiments indicated that after 17th day of BM transplantation, significant numbers of T & B cells appeared in the reconstituted mouse spleen. However, when AF-SWCNTs pretreated BM cells used to reconstitute irradiated mice, significant decline in both of their percentage & absolute recovery was noted. These results indicate that CNTs may significantly modulate the differentiation of HSCs into lymphocytes.