Graphene Oxide Quantum Dots-Induced Mineralization via the Reactive Oxygen Species-Dependent Autophagy Pathway in Dental Pulp Stem Cells

Abstract

As an important recycling and degradation system, autophagy is considered to be critical in regulating stem cell differentiation. It has been shown that graphene oxide quantum dots (GOQDs) are a robust biological labelling tool for stem cells with little cytotoxicity. In this study, we explored the role of autophagy in regulating the impact of GOQDs on the odontoblastic differentiation of DPSCs during autophagy. Western blotting and immunofluorescence staining were used to evaluate the autophagic activity of DPSCs. Quantitative PCR, alizarin red S staining, and alkaline phosphatase staining were used to examine DPSC odontoblastic differentiation. The impacts of ROS scavengers on autophagy induction and reactive oxygen species (ROS) levels were also measured. Lentiviral vectors carrying Beclin1 siRNA sequences, as well as autophagy inhibitors (3-MA and bafilomycin A1), were used to inhibit autophagy. Initial exposure to GOQDs increased autophagic activity and enhanced DPSC mineralization. Autophagy inhibition suppressed GOQD-induced odontoblastic differentiation. Moreover, GOQD treatment induced autophagy in a ROS-dependent manner. GOQDs promoted differentiation, which could be modulated via ROS-induced autophagy.

Modulation of Cancer Cell Autophagic Responses by Graphene-Based Nanomaterials: Molecular Mechanisms and Therapeutic Implications

“…Nevertheless, as it is still expected that a certain number of healthy cells will be exposed to GNM during the therapy, it is important to assess the responses of normal cells to autophagy-modulating action of GNM. While in some studies cytotoxicity was observed [95][96][97][98][99], GNM-induced autophagy in healthy, non-transformed primary cells was usually not associated with significant cell death [100][101][102][103][104][105][106]. The certain types of normal cells such as mouse lymphocytes and monkey fibroblasts were apparently resistant to both autophagy-modulating and cytotoxic action of GNM [107,108].…”

Graphene Family Nanomaterials for Stem Cell Neurogenic Differentiation and Peripheral Nerve Regeneration

“…Similarly, both graphene oxide quantum dots (GOQDs) and reduced graphene oxide quantum dots (rGOQDs) show negligible cytotoxicity, thus being used as a biological labeling tool for stem cells. 50,51 It turned out to be a promising way to reduce toxicity.…”

“…What’s more, Lee et al proved that GQDs could protect the body from excessive inflammation by promoting macrophage polarization from activated M1 to M2. Similarly, both graphene oxide quantum dots (GOQDs) and reduced graphene oxide quantum dots (rGOQDs) show negligible cytotoxicity, thus being used as a biological labeling tool for stem cells. , It turned out to be a promising way to reduce toxicity.…”

New insights into the safety assessment of quantum dots: potential release pathways, environmental transformations, and health risks

“…302–305 CdTe QDs can trigger mitochondrial dysfunction in hepatocytes via ROS, leading to apoptosis, 306 and CdSe/ZnS QDs can lead to ROS accumulation, altered phagocytosis, and increased apoptosis in macrophages. 211 The excessive accumulation of ROS generated by QDs which can mediate not only the induction of apoptosis but also other forms of ROS-mediated cell death can also be triggered, such as autophagy, 307–312 inflammation, 201,203,216,313–316 pyroptosis, 203,214,316 necrosis, 317–319 and ferroptosis. 320…”