Small, Thin Graphene Oxide Is Anti-inflammatory Activating Nuclear Factor Erythroid 2-Related Factor 2 via Metabolic Reprogramming

Abstract

Graphene oxide (GO), an oxidized form of graphene, has potential applications in biomedical research. However, how GO interacts with biological systems, including the innate immune system, is poorly understood. Here, we elucidate the effects of GO sheets on macrophages, identifying distinctive effects of GO on the inflammatory phenotype. Small, thin (s)-GO dose-dependently inhibited release of interleukin (IL)-1β and IL-6 but not tumor necrosis factor α. NLRP3 inflammasome and caspase-1 activation was not affected. The effect of s-GO was pretranslational, as s-GO blocked Toll-like receptor 4-dependent expression of Il1b and Il6 but not Nlrp3 or Tnf mRNA transcripts. s-GO was internalized by immortalized bone-marrow-derived macrophages, suggesting a potential intracellular action. Uptake of polystyrene beads with similar lateral dimensions and surface charge did not phenocopy the effects of s-GO, suggesting that s-GO-mediated inhibition of interleukin expression was not simply due to particle phagocytosis. RNA-Seq analysis established that s-GO had profound effects on the immunometabolism of the cells, leading to activation of the transcription factor nuclear factor erythroid 2-related factor 2, which inhibited expression of cytokines such as IL-1β and IL-6. Thus, we have identified immunometabolic effects of GO that reveal another dimension to its effects on cells. These findings suggest that s-GO may be used as a valuable tool to generate further insights into inflammatory mechanisms and indicate its potential applications in biomedicine.

Interactions of graphene oxide and graphene nanoplatelets with the in vitro Caco-2/HT29 model of intestinal barrier

“…In our study, we have found a decrease in the expression of the major pro-inflammatory IL-1 cytokines after the exposure to both GO and GNPs. This would agree with the observations made on macrophages exposed to GO, where a dose-dependent inhibition of interleukin IL-1 and IL-6 were observed 45 . This would also agree with the results obtained using a nanocomposite formed by GO and AgNPs, where the primary murine macrophages exposed did not produce inflammatory cytokines 46 .…”

Cytotoxicity and Immune Dysfunction of Dendritic Cells Caused by Graphene Oxide

“…Hoyle et al found that GO had no significant inflammatory response to macrophages cells. However, GO inhibited Toll-like receptor 4 (TLR4) receptor-mediated interleukin production, but did not inhibit activation of inflammatory bodies (Hoyle et al, 2018). However, little is known about the effect of GO on dendritic cells (DCs), which were the most powerful professional antigen-presenting cells (APCs).…”

Carbon Nanomaterials Applied for the Treatment of Inflammatory Diseases: Preclinical Evidence

“…- [64] GO Sepsis iNKT cells/regulatory T cells/DCs -Galactosylceramidetreated mice [65] GQDs Inflammation DCs, phytohemagglutinin-stimulated PBMCs - [66] GQDs…”

“…For instance, GO with a lateral dimension between 30 nm and 3 µm showed no toxicity and displayed no proinflammatory effect at concentrations up to 25 µg mL −1 . [64] GO was able to significantly inhibit the release of proinflammatory cytokines such as IL-1 and IL-6 in murine immortalized bone-marrow-derived macrophages (iBMDMs) (Figure 7). To better understand the mechanism of action of GO, RNAsequence analyses were performed on iBMDMs treated with GO prior to lipopolysaccharide (LPS) priming.…”