Automobile diesel exhaust particles induce lipid droplet formation in macrophages in vitro

J of Applied Toxicology

et al. 2019

Self Cite

We recently synthesized ZnO nanomaterials (denoted as ZnO nanorods [NRs] and Mini‐NRs) and suggested that their cytotoxicity could be related with the activation of endoplasmic reticulum (ER) stress apoptosis. However, in a complex biological microenvironment, the ER stress‐apoptosis pathway could also be modulated by biological molecules, such as free fatty acids, leading to unpredicted biological effects. In this study, we investigated the combined toxicity of ZnO NRs/Mini‐NRs and palmitate (PA) to THP‐1 macrophages. PA influenced the zeta potential and solubility of ZnO NRs and ZnO Mini‐NRs in water, which indicated a change of colloidal stability. Exposure to ZnO NRs and Mini‐NRs dose‐dependent decreased cellular viability and release of soluble monocyte chemotactic protein 1 (sMCP‐1), and these effects were significantly promoted with the presence of PA. However, ZnO NR‐ and Mini‐NR‐induced intracellular Zn ions or reactive oxygen species were not significantly affected by PA. ZnO NRs and ZnO Mini‐NRs significantly promoted the expression of ER stress genes HSPA5, DDIT3, XBP‐1s and apoptotic gene CASP3, whereas PA also modestly promoted the expression of HSPA5, DDIT3 and CASP3. Interestingly, the ER stress inducer thapsigargin showed a similar effect as PA to promote the cytotoxicity of ZnO NRs and ZnO Mini‐NRs. It is suggested that PA might promote the cytotoxicity of ZnO NRs and ZnO Mini‐NRs possibly by promoting ER stress.

Section: Methodsmentioning

confidence: 99%

Palmitate enhanced the cytotoxicity of ZnO nanomaterials possibly by promoting endoplasmic reticulum stress

Chen

Yang

J of Applied Toxicology

et al. 2019

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“…The intracellular ROS was measured using a general ROS indicator dichloro‐dihydro‐fluorescein diacetate as previously described (Cao et al, ). Briefly, HepG2 cells grown on to 96‐well black plates were exposed to various concentrations of ZnO NMs for 3 hours.…”

Section: Methodsmentioning

confidence: 99%

The toxicity of ZnO nanomaterials to HepG2 cells: the influence of size and shape of particles

Yan

J of Applied Toxicology

Liu

et al. 2018

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Understanding the possible role of physicochemical properties in determining the toxicity of ZnO nanomaterials (NMs) is crucial for the safe use of ZnO-based materials. In this study, we synthesized four types of ZnO NMs, and characterized them as ZnO nanorods (NRs; length 400-500 nm, diameter 150-200 nm), ZnO Mini-NRs (length 50-100 nm, diameter 15-20 nm), amorphous ZnO microspheres (a-ZnO MS) and crystalline ZnO MS (c-ZnO MS; the a/c-ZnO MS are nanoflowers with an extensive growth of sheet-like structures). ZnO NMs and ZnO Mini-NRs were significantly more cytotoxic than a/c-ZnO MS, and this trend was similar in both HepG2 cells and human umbilical vein endothelial cells. Intracellular reactive oxygen species was only modestly induced by c-ZnO MS, whereas intracellular Zn ions were dose-dependently increased in HepG2 cells by the exposure of all types of ZnO NMs. The expression of endoplasmic reticulum stress marker DDIT3 was induced following an order of ZnO NRs > a-ZnO MS > c-ZnO MS > ZnO Mini-NRs, and the apoptosis gene CASP12 was induced following an order of a-ZnO MS > ZnO NRs > c-ZnO MS > ZnO Mini-NRs. Combined, these results suggested that ZnO NM-induced cytotoxicity and expression of endoplasmic reticulum stress-apoptosis genes could be influenced by the size and shape of ZnO NMs.

“…The assay was done as previously described. 13 Briefly, HASMCs were seeded at a density of 10 4 per well in 96-well black plates. After being grown for 2 days, cells were incubated with 0 µg/mL (control), 4 µg/mL, 8 µg/mL, 16 µg/mL, 32 µg/mL, and 64 µg/mL NPs.…”

Section: Intracellular Rosmentioning

confidence: 99%

A comparative study of toxicity of TiO<sub>2</sub>, ZnO, and Ag nanoparticles to human aortic smooth-muscle cells

Wang

Yang

et al. 2018

IJN

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PurposeTo evaluate the adverse vascular effects of nanoparticles (NPs) in vitro, extensive studies have investigated the toxicity of NPs on endothelial cells, but the knowledge of potential toxicity on human smooth-muscle cells (SMCs) is currently limited.MethodsThis study compared the toxicity of TiO2, ZnO, and Ag NPs to human aortic SMCs.ResultsOnly ZnO NPs significantly induced cytotoxicity, accompanied by increased intracellular reactive oxygen species, Zn ions, and endoplasmic reticulum stress biomarkers (DDIT3 expression and p-Chop proteins). All the NPs significantly promoted the release of soluble VCAM1 and soluble sICAM1, but not IL6, which suggested that metal-based NPs might promote inflammatory responses. Furthermore, KLF4 expression (a transcription factor for SMC-phenotype switch) was significantly induced by TiO2 NPs and modestly by ZnO NPs, but the expression of CD68 remained unaltered.ConclusionOur data indicated that ZnO NPs were more cytotoxic to human aortic SMCs than TiO2 and Ag NPs at the same mass concentrations, which might have been associated with intracellular reactive oxygen species, Zn ions, and endoplasmic reticulum stress.