Nitric Oxide Is an Important Regulator of Heme Oxygenase-1 Expression in the Lipopolysaccharide and Interferon-γ-Treated Murine Macrophage-Like Cell Line J774.1/JA-4

Abstract

1,2) Macrophages use a wide variety of pattern recognition receptors including Toll-like receptors (TLRs) that bind to these agents.3,4) Such receptors recognize various microbial components. 5) Once TLRs sense the presence of invading pathogens, their engagement with them activates macrophages, which then produce and release various sets of effector molecules aimed at destroying the foreign agents. Reactive oxygen species (ROS), such as superoxide anion (O 2 − ), hydrogen peroxide (H 2 O 2 ), and nitric oxide (NO), are their front line effector molecules.6-11) These highly diffusive products exert strong cytotoxic activities against micro-organisms and many neighboring cells, including against the macrophages themselves. However, macrophages and most of the aerobic host cells can protect themselves by enhancing the expression of heme oxygenase (HO). HO, a cellular antioxidant, is one of the key enzymes catalyzing the degradation of heme-containing molecules to biliverdin, free iron, and carbon monoxide.12,13) Three HO isozymes, including HO-1 (HSP32), HO-2, and HO-3, have been identified 14) ; although HO-3 may be a pseudo gene derived from HO-2 transcripts. 15)HO-1 is an inducible enzyme, whereas HO-2 is constitutive one.16) HO-1 is induced by various molecules and environmental factors, such as heme, radiation, cytokine, oxidative, and heat stresses. [17][18][19][20][21] Previous studies reported that lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria, also induces the expression of both the HO-1 gene and its protein in macrophages.22-24) Exposure of HO-1-deficient mice to LPS leads to increased hepatocellular necrosis, increased splenic proinflammatory cytokine secretion, and higher mortality of septic shock when compared with wild-type animals. 25,26) These studies suggest that HO-1 plays an important role in reducing the deleterious increase in oxidative damage. Srisook et al. reported that both O 2 − and NO are related to HO-1 induction in macrophages by using an O 2 − generator and a NO donor. 27) However, it is not easy to study the role of O 2 − and NO separately in HO-1 induction in activated macrophages which produce both of these molecules simultaneously after LPS-treatment. Thus, among ROS, the important regulators of HO-1 in the activated macrophages have not been clear. The aim of the present work was to identify the regulator of HO-1 induction in activated macrophages. In this study, we sought to identify the regulator of HO-1 induction of the activated macrophages by using 2 types of macrophages, i.e., cells of the murine macrophage-like cell line J774.1/JA-4 and their LPS-resistant mutant, LPS1916. 7) This mutant cell line is characterized by a specific defect in the induction of ROS after LPS treatment. Our recent study reported that LPS1916 cells have the phenotype of mal-expression of CD14, a key molecule required for LPS-induced activation of cells, on the macrophage cell surface, leading to reduced responses to LPS. 28) Interestingly, this defect i...

Edaravone protects rats and human pulmonary alveolar epithelial cells against hyperoxia injury: heme oxygenase-1 and PI3K/Akt pathway may be involved

“…that derived from increased eNOS expression, but without peroxynitrite (ONOO-) generation [44]. NO can sequentially affect the Akt and HO-1 systems profoundly [45,46]. A serious limitation of the present study is that the interaction between edaravone, eNOS, NO and the Akt/HO-1 pathway is not investigated.…”

Simultaneous Addition of Shikonin and Its Derivatives with Lipopolysaccharide Induces Rapid Macrophage Death

“…11,12,21,27) However, we consider that the cytotoxicity of SHK in LPS-treated macrophages may also contribute to the anti-inflammatory effect. Because, in progression of inflammation, it is important that although activated macrophages secretion of inflammatory cytokines, newly activated macrophages participate in amplifying the inflammatory response; our present findings may suggest that SHK derivatives inhibit the aggravation of inflammatory response by inducing cell death of newly activated macrophages.…”

“…Some of the latest research has focused on SHK's beneficial effect in anti-inflammatory treatment. 11,12) These reports stated that SHK may exhibit anti-inflammatory effects in various inflammatory stages through regulation of macrophage activation. However, there have been a limited number of reports on the direct cytotoxic effects of SHK on macrophages.…”

Expression of Cyclooxygenase-2, Nitric Oxide Synthase 2 and Heme Oxygenase-1 mRNA Induced by Bis-Eugenol in RAW264.7 Cells and their Antioxidant Activity Determined Using the Induction Period Method

“…HO-1 has also been shown to be an oxidative stress-responsive gene that may exert important roles in cytoprotection and the resolution of inflammation to maintain tissue homeostasis (12,38). In most cell types, HO-1 is inducible by heme, radiation, cytokines, inflammatory stimuli, and oxidative and heat stress (39). Recent studies have demonstrated that overexpression of HO-1 prior to stimulation with LPS markedly inhibits the production of subsequent inflammatory mediators such as nitric oxide (NO), interleukin-6, and monocyte chemoattractant protein (MCP-1) (40,41).…”