Autophagy in RAW264.7 Cells Treated with Surface‐Functionalized Graphene Oxides

Abstract

This study investigated cytotoxicity, particularly autophagy, in RAW264.7 cells exposed to graphene oxide (GO) and its derivatives (dodecylamine-GO (DA-GO), reduced GO (rGO), and sodium dodecyl sulfate-rGO (SDS-rGO)). Appearance of amine stretching bands, out-of-plane C-H stretching vibrations, and S=O stretching bands in infrared spectra indicated the formation of DA-GO, rGO, and SDS-rGO, respectively. Light microscopy and microculture tetrazolium assay showed that all the GO types exerted cytotoxic effects on RAW264.7 cells in a concentration-dependent manner. Higher concentrations of the GO types downregulated the expression of PU.1, a unique transcription factor in monocytes and macrophages, and decreased the conversion of LC3A/B-I to LC3A/B-II, suggesting that PU.1 was associated with autophagy in RAW264.7 cells. These results suggested that surface-functionalized GOs exerted cytotoxic effects in a concentration-dependent manner by changing the expression of critical genes and inducing autophagy in macrophages.

Cytotoxicity-Related Bioeffects Induced by Nanoparticles: The Role of Surface Chemistry

“…In A549 cells, NH 2 -graphene quantum dots (GQDs) induced cellular autophagy as evidenced by LC3 fluorescence tracking, LC3-II conversion, and autophagosome accumulation, while COOH-GQDs had no impact of autophagy (Xie Y. et al, 2019). In another study, the autophagy level induced by GO-decorated NPs with neutrally charged ligands was slightly higher than that of the negatively charged decorated NPs in RAW264.7 cells (Park et al, 2015). Therefore, it seems that positively and neutrally charged NPs are more likely to induce autophagy than are negatively charged NPs.…”