More serious autophagy can be induced by ZnO nanoparticles than single‐walled carbon nanotubes in rat tracheal epithelial cells

Abstract

Metal oxide nanoparticles and carbon nanoparticles, as common nanoparticles (NPs), can cause autophagy in certain cells, which will lead to biohealth risk issues. This study determined the difference in autophagy induced by zinc oxide nanoparticles (ZnO NPs) and single‐walled carbon nanotubes (SWCNTs) in respiratory epithelial cells. ICP‐OES results showed that NPs uptake as well as the intercellular contents of particles affected cytotoxicity in a dose‐dependent manner. ZnO NPs‐30 nm had a distinct green dot structure representing autophagy, the SWCNTs exposure group had a few green light spots at a concentration of 10 μg/L. The ROS content of the ZnO NP‐30 nm exposure group had the greatest increase at a concentration of 1000 μg/L, which was 2.5 times higher than that of the control, the SWCNTs exposure group showed a 2.2‐fold increase. A slight downregulation of p‐mTOR was detected, and the ZnO NPs‐30 nm treatment group had the significant downregulation rate. The gene and protein expression levels of Beclin‐1 and LC3B were upregulated as the exposure concentration increased. The protein expression of Beclin‐1 and LC3B in the 1000 μg/L ZnO NPs‐30 nm exposure group were 5.21 times and 4.12 times that of the control, respectively. The mRNA expression of Beclin‐1 and LC3B in the 1000 μg/L ZnO NPs‐30 nm exposure group were 5.04 times and 3.61 times that of the control, respectively. At any concentration, the effect of ZnO NPs‐30 nm was greater than that of the SWCNTs. Interaction and crosstalk analysis showed that exposure to ZnO NPs‐30 nm caused autophagy through the aggregation of undegraded autophagosomes, whereas SWCNTs exposure induced diminished intercellular oxidative stress to inhibit autophagy. Therefore, this study demonstrated that the effects of autophagy induced by ZnO NPs‐30 nm and SWCNTs were different. The health risks of ZnO‐30 nm NPs are higher than those of SWCNTs.

Zinc Oxide Nanoparticles Exacerbate Epileptic Seizures by Modulating the TLR4-Autophagy Axis

“…And it has also been reported that the effect of ZnO NPs on autophagy is crucial. [29][30][31] Interestingly, we found that TLR4 expression was altered in the autophagy pathway. In previous studies, the activation of TLR4 has been reported to affect autophagy through different signaling pathways.…”

Zinc Oxide Nanoparticles (ZnO-NPs) Suppress Fertility by Activating Autophagy, Apoptosis, and Oxidative Stress in the Developing Oocytes of Female Zebrafish

“…More than 20 genes, including the Atg5, Atg7, and atg12 genes, can encode the proteins necessary for the autophagy field execution [ 69 ]. Numerous works have shown that ZnO-NPs can increase the expression of atg genes, particularly atg5 and atg7, and the proteins involved in the production of the autophagosome [ 68 , 70 , 71 ].…”

Nanosized copper particles induced mesangial cell toxicity via the autophagy pathway

“…Autophagy has been shown to be involved in the toxicity of nanoparticles, and ROS are known inducers of autophagy ( 26 , 27 ). Zinc oxide nanoparticles and single-walled carbon nanotubes (SWCNTs) have been reported to cause autophagy in rat tracheal epithelial cells ( 28 ), and silver nanoparticles can induce cytotoxicity in mouse hippocampal neuronal HT22 cells by increasing autophagy ( 29 ). We were interested in knowing whether autophagy is involved in the nano Cu-induced apoptosis of MCs.…”