Monocyte adhesion induced by multi-walled carbon nanotubes and palmitic acid in endothelial cells and alveolar–endothelial co-cultures

Abstract

Free palmitic acid (PA) is a potential pro-atherogenic stimulus that may aggravate particle-mediated cardiovascular health effects. We hypothesized that the presence of PA can aggravate oxidative stress and endothelial activation induced by multi-walled carbon nanotube (MWCNT) exposure in vitro. We investigated the interaction between direct exposure to MWCNTs and PA on THP-1 monocyte adhesion to human umbilical vein endothelial cells (HUVECs), as well as on indirect exposure in an alveolar-endothelial co-culture model with A549 cells and THP-1-derived macrophages exposed in inserts and the effect measured in the lower chamber on HUVECs and THP-1 cells. The exposure to MWCNTs, including a short (NM400) and long (NM402) type of entangled fibers, was associated with elevated levels of reactive oxygen species as well as a decrease in the intracellular glutathione concentration in HUVEC and A549 monocultures. Both effects were found to be independent of the presence of PA. MWCNT exposure significantly increased THP-1 monocyte adhesion to HUVECs, and co-exposure to PA aggravated the NM400-mediated adhesion but decreased the NM402-mediated adhesion. For the co-cultures, the exposure of A549 cells did not promote THP-1 adhesion to HUVECs in the lower chamber. When THP-1 macrophages were present on the cell culture inserts, there was a modest increase in the adhesion and an increase in interleukin-6 and interleukin-8 levels in the lower chamber whereas no tumor necrosis factor was detected. Overall, this study showed that direct exposure of HUVECs to MWCNTs was associated with oxidative stress and monocyte adhesion and the presence of PA increased the adhesion when exposed to NM400.

The Interactions between ZnO Nanoparticles (NPs) and α-Linolenic Acid (LNA) Complexed to BSA Did Not Influence the Toxicity of ZnO NPs on HepG2 Cells

“…However, it is expected that BSA or LNA will show similar effects on the hydrodynamic sizes and Zeta potential of ZnO NPs when added into the cell culture medium. Previously, it was shown that the salt of SFA or SFA complexed to BSA may coat NPs, showing as altered hydrodynamic sizes and/or zeta potential of NPs [10,11,12,13]. The results from the present study further indicated that the presence of BSA or LNA complexed to BSA could coat ZnO NPs and, consequently, stabilize the NPs.…”

“…For example, the presence of a typical saturated fatty acid (SFA), palmitic acid (100 µM) promoted multi-walled carbon nanotube-mediated adhesion of THP-1 monocytes onto human endothelial cells without an effect on production of the intracellular reactive oxygen species (ROS) or depletion of glutathione (GSH) [10]. In contrast, co-exposure to 200 µM palmitate and ZnO NPs did not significantly affect THP-1 monocyte adhesion, but induced higher cytotoxicity to human endothelial cells due to combined toxicity of palmitate and ZnO NPs [11].…”

The use of human umbilical vein endothelial cells (HUVECs) as an in vitro model to assess the toxicity of nanoparticles to endothelium: a review

“…ICAM‐1, VCAM‐1 and selectins) have been observed in HUVECs after exposure to a variety of NPs, including carbonaceous NPs (CB NPs and carbon nanotubes) (Vesterdal et al, ; Cao et al, , ), metal‐based NPs (Ag, ZnO and TiO 2 NPs) (Li et al, ; Montiel‐Davalos et al, ; Shi et al, ; Suzuki et al, ; Danielsen et al, ;) and silica NPs (Corbalan et al, ; Duan et al, ; Guo et al, ). Some studies also showed increased monocyte adhesion to NP‐exposed HUVECs, which is in agreement with the increased expression of adhesion molecules (Danielsen et al, ; Cao et al, ; Cao et al, ; Shi et al, ; Suzuki et al, ). However, it should be noticed that monocyte adhesion to HUVECs is not always correlated with the expression of adhesion molecules.…”

“…Besides proteins, the interactions between NPs and excessive nutrients may also need further investigations (Cao et al, ). For example, it has been shown that the presence of palmitic acid, a saturated fatty acid, coated MWCNT and promoted MWCNT‐induced monocyte adhesion to HUVECs without an effect on oxidative stress (Cao et al, ). In our recent study, we showed that the presence of palmitate could coat ZnO NPs but did not significantly affect ZnO NP‐induced monocyte adhesion or the release of inflammatory cytokines in HUVECs.…”

A Flow Cytometry‐based Method for the Screening of Nanomaterial‐induced Reactive Oxygen Species Production in Leukocytes Subpopulations in Whole Blood

“…This approach is common in toxicological studies on primary cell cultures. For instance, we have used pooled batches of endothelial cells from several donors for studies on liposomes and carbon nanotubes [58][59][60]. The flow cytometry-based detection of ROS production in blood samples can be further developed for investigations of interindividual differences in response to NMs in healthy individuals, susceptible groups or patients with specific diseases.…”