Autophagic and apoptotic changes in macrophages in response to graphene oxides with or without chemical modification

Abstract

Fine dust particles can derived from desert and industrial derivatives. The graphene, an allotrope of carbon, has the honeycombing structure of one-atom-thick planar sheets, is widely used for the modern electronics, informative technologies including medical devices. It may provoke various immune responses. We tested the autophagic and apoptotic response of macrophages in response to graphene and its chemically modified compounds. Raw264.7 cells were treated with graphene oxide(GO), reduced GO(RGO), SDS-GO, dodecyl amine(DA)-GO with different concentrations and times. MTT assay and Western blotting for PU.1, mTOR, NBR1, p62, Beclin-1 and LC3-A/B-I/II. The cell viability was reduced after treatment of 4 kinds of GO compounds in macrophages in light microscopy and MTT assay. PU.1 decrease was more remarkable in response to treatment of GO compounds- dose dependent manner than R-, DA- and SDS-GO. LC3-A/B-I to LC3A/B-II conversion was dose-dependently decreased after treatment of four GO’s. The expressional levels of mTOR and NBR1 showed similar manner in GO but not remarkable in other three compounds.P62 and Bec-1 were not remarkably changed in four GO compounds. Although the cell viability decreased in GO-treated macrophages, autophagy, apoptosis and PU.1 decreased in higher concentrations of GO compounds. These findings may suggest the other important complicated mechanisms of cellular injury in macrophages. Further evaluation may be necessary.