Metabolic Impact of 4-Hydroxynonenal on Macrophage-Like RAW 264.7 Function and Activation

Abstract

Metabolic profiling of macrophage metabolic response upon exposure to 4-hydroxynonenal (HNE) demonstrates that HNE does not simply inactivate superoxide generating enzymes but could also be responsible for the impairment of downfield signaling pathways. Multianalyte microphysiometry (MAMP) was employed to simultaneously measure perturbations in extracellular acidification, lactate production and oxygen consumption for the examination of aerobic and anaerobic pathways. Combining the activation of oxidative burst with phorbol myristate acetate (PMA) and the immunosuppression with HNE, the complex nature of HNE toxicity was determined to be concentration- and time-dependent. Further analysis was utilized to assess the temporal effect of HNE on reactive oxygen species (ROS) production and on protein kinase C (PKC). Increased levels of HNE with decreasing PKC activity suggest PKC is a target for HNE adductation prior to oxidative burst. Additionally, localization of PKC to the cell membrane was prevented with the introduction of HNE, demonstrating a consequence of HNE adductation on NADPH activation. The impairment of ROS by HNE suggests HNE has a greater role in foam cell formation and tissue damage than is already known. Although work has been performed to understand the effect of HNE’s regulation of specific signaling pathways, details regarding its involvement in cellular metabolism as a whole are generally unknown. This study examines the impact of HNE on macrophage oxidative burst and identifies PKC as a key protein for HNE suppression and eventual metabolic response.

<i>Gsta</i>4 Null Mouse Embryonic Fibroblasts Exhibit Enhanced Sensitivity to Oxidants: Role of 4-Hydroxynonenal in Oxidant Toxicity

“…The observed hypersensitivity of Gsta 4 null MEF cells to oxidants and the correlation of this sensitivity with increased accumulation of 4-HNE-protein adducts is consistent with previous findings [44, 45], suggesting that oxidative damage to cells leads to significant increases in 4-HNE adducts and overexpres-sion or induction of GSTA4–4 prevents such accretion [13]. Rapid release of reactive oxygen species such as superoxide radical and hydrogen peroxide during oxidative stress leads to formation of the lipid peroxidation product 4-HNE, which could be responsible for the impairment of downfield protective mechanisms in the cellular system [46]. Increased sensitivity of Gsta 4 null MEF towards unrelated substrates (H 2 O 2 and paraquat) of GSTA4–4 during in vitro treatment is possibly due to excessive production of 4-HNE by treated cells.…”

Lipid Peroxidation: Production, Metabolism, and Signaling Mechanisms of Malondialdehyde and 4-Hydroxy-2-Nonenal

“…Phagocytes, such as granulocytes and monocytes/macrophages which engulf microbial intruders and effectively kill and eradicate the foreign bodies, contain a membrane-associated NADPH oxidase that produces superoxide leading to other ROS with microbicidal, tumoricidal, and inflammatory activities [ 294 ]. In RAW 264.7 mouse macrophage cells, 4-HNE exhibited a concentration-dependent inhibition of ROS by adduction to PKC, a protein vital in the assembly and activation of NADPH oxidase [ 295 ]. In rat hepatocyte PKC- isoforms activity is differentially regulated by concentrations 4-HNE.…”

Pleiotropic effects of 4-hydroxynonenal on oxidative burst and phagocytosis in neutrophils

“…Previous studies have shown that 4-HNE can modify neutrophil and macrophage oxidative burst responses in human and mouse samples [29] , [30] . Compromised oxidative burst responses to the bacterial peptide N-formylmethionyl-leucyl-phenylalanine (fMLP) and PMA by 4-HNE treated macrophages have also been shown in vitro studies, suggesting oxidative damage to these cell types [31] . However, the mechanisms of these responses are not well established.…”