1‐Nitropyrene Induced Reactive Oxygen Species–Mediated Apoptosis in Macrophages through AIF Nuclear Translocation and AMPK/Nrf‐2/HO‐1 Pathway Activation

Abstract

1-Nitropyrene (1-NP), one of the most abundant nitropolycyclic aromatic hydrocarbons (nitro-PAHs), is generated from the incomplete combustion of carbonaceous organic compounds. 1-NP is a specific marker of diesel exhaust and is an environmental pollutant and a probable carcinogen. Macrophages participate in immune defense against the invasive pathogens in heart, lung, and kidney infection diseases. However, no evidence has indicated that 1-NP induces apoptosis in macrophages. In the present study, 1-NP was found to induce concentration-dependent changes in various cellular functions of RAW264.7 macrophages including cell viability reduction; apoptosis generation; mitochondrial dysfunction; apoptosis-inducing factor (AIF) nuclear translocation; intracellular ROS generation; activation of the AMPK/Nrf-2/HO-1 pathway; changes in the expression of BCL-2 family proteins; and depletion of antioxidative enzymes (AOE), such as glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) These results indicate that 1-NP induced apoptosis in macrophages through AIF nuclear translocation and ROS generation due to mitochondrial dysfunction and to the depletion of AOE from the activation of the AMPK/Nrf-2/HO-1 pathway.

Proinflammatory Responses of 1-Nitropyrene against RAW264.7 Macrophages through Akt Phosphorylation and NF-κB Pathways

“…After 1-NP was incubated with RAW264.7 cells for 12 h, the cytotoxicity was approximately 10, 20, and 35% at concentrations of 10, 30, and 50 µM, respectively. After 1-NP was incubated with RAW264.7 cells for 24 h and 48 h, more serious levels of cytotoxicity were generated [11,12]. Based on these findings, we suggest that cytotoxicity induced by 1-NP cannot be recovered.…”

“…These findings suggest that the cytotoxicity induced by 1-NP cannot be recovered. In addition, the cytotoxicity and genotoxicity induced by 1-NP may occur via intracellular accumulation and metabolism [11,12]. Based on these findings, we hypothesise that the proinflammatory response is higher than the toxic effects after 1-NP is incubated with RAW264.7 cells for 12 h.…”

“…RAW264.7 murine macrophage-like cells purchased from the Bioresource Collection and Research Centre (BCRC, Hsinchu, Taiwan) were cultured in DMEM supplemented with 50 IU/mL penicillin and 100 µg/mL streptomycin at 37 • C in an atmosphere of 5% CO 2 and 95% air. RAW264.7 cells were plated at a density of 5 × 10 5 cells/mL for 12 h, then the medium was replaced with a serum-free DMEM medium [11,12]. After cell incubation with 1-NP at the concentrations of 0, 3, 10, 30, and 50 µM for 30 min or 12 h, supernatants were collected for an enzyme-linked immunosorbent assay (ELISA) and Griess reaction assays; the cells were harvested for a protein expression assay.…”

“…Known as a nitro-polycyclic aromatic hydrocarbon and the most abundant nitroarene in diesel engine exhaust, 1-nitropyrene (1-NP) results from the incomplete combustion of carbonaceous organic substances [6,7]. Genotoxicity and apoptosis are induced by 1-NP in macrophages, liver and lung epithelial cells, and hepatoma cells [8][9][10][11][12]. Chronic inflammation in pulmonary fibrosis is induced by 1-NP through endoplasmic reticulum stress in mice [13].…”

ICA69 aggravates ferroptosis causing septic cardiac dysfunction via STING trafficking

“…It is well-known that lipopolysaccharide (LPS) is an effective activator of sepsis to release a good amount of pro-inflammatory cytokines in monocytes [ 19 ]. Macrophages are a group of mononuclear phagocytes that participate in immune defense against invasive pathogens in heart, lung, and kidney infections [ 20 ]. RAW264.7 cells incubated by LPS is a widely accepted in vitro model for discovering sepsis [ 21 ].…”