(562d) Graduate Student Award Session: Effects of Nanoscale Magnetite on Human Forebrain-like Tissue Development in Stem Cell-Derived Cortical Spheroids
AIChE Annual Meeting
2021 Annual Meeting
Materials Engineering and Sciences Division
Biomaterials: Graduate Student Award Session
Thursday, November 11, 2021 - 8:54am to 9:12am
Methods: Human brain cortical organoids were derived by sequentially treating human iPSK3 cells with dual SMAD inhibitors to promote neural progenitors, followed by the combination of basic fibroblast growth factor 2 and sonic hedgehog inhibitor cyclopamine. The iron oxide nanoparticles (NP) of 8 nm and 15 nm were added to the culture from day 4-30 at concentrations of 0.00 Âµg/mL, 0.023 Âµg/mL, 2.3 Âµg/mL, and 23 Âµg/mL. The spheroids were characterized with iron staining assay, as well as RT-PCR, immunocytochemistry, and flow cytometry for various markers of cellular stress and neurons.
Results: Regardless of the size, the higher magnetite concentration treatment showed higher accumulation in the cells. Cellular death was not significantly different when compared with the control. The 15 nm NP treatment only increased the SOD2 and Î²-tubulin III expression for the 2.34 µg/mL. In general, gene expression for the 8 nm NP treated spheroids showed an increase in the markers of cellular stress and ROS response with a minor increase in DNA damage but not the apoptosis markers. On the other hand, the 15 nm NP-treated spheroids did not show significant changes for cellular stress markers and the DNA repair marker. Tp53 was similar across all the treatment and slightly higher for the 2.3 µg/mL group. The cellular stress and ROS response were comparable or lower to the untreated group.
Conclusion: Although the cell viability was not significantly different across the tested conditions, the neuronal spheroids exposed to 8 nm iron oxide showed negative effects (i.e., increased inflammation and ROS response genes), whereas those exposed to 15 nm iron oxide treatment demonstrate a slightly positive effect (i.e., decreased inflammation, apoptosis, and ROS response, and cleaned up genes). It is postulated that the cells treated with 8 nm may have higher number of iron oxide particles, and these excessive iron oxide particles may disturb the cellular iron metabolism and cause adverse effects. This hypothesis remains to be investigated in the future.