Effects of IFN-γ on intracellular trafficking and activity of macrophage NADPH oxidase flavocytochrome b558

We generated and studied CLIC1 null (C1KO) mice to investigate the physiological role of this protein. C1KO and matched wild‐type (WT) mice were studied in two models of acute toxic tissue injury. CLIC1 expression is upregulated following acute injury of WT kidney and pancreas and is absent in C1KOs. Acute tissue injury is attenuated in the C1KOs and this correlates with an absence of the rise in tissue reactive oxygen species (ROS) that is seen in WT mice. Infiltration of injured tissue by inflammatory cells was comparable between WT and C1KOs. Absence of CLIC1 increased PMA‐induced superoxide production by isolated peritoneal neutrophils but dramatically decreased PMA‐induced superoxide production by peritoneal macrophages. CLIC1 is expressed in both neutrophils and macrophages in a peripheral pattern consistent with either plasma membrane or the cortical cytoskeleton in resting cells and redistributes away from the periphery following PMA stimulation in both cell types. Absence of CLIC1 had no effect on redistribution or dephosphorylation of Ezrin/ERM cytoskeleton in macrophages. Plasma membrane chloride conductance is altered in the absence of CLIC1, but not in a way that would be expected to block superoxide production. NADPH oxidase redistributes from an intracellular compartment to the plasma membrane when WT macrophages are stimulated to produce superoxide and this redistribution fails to occur in C1KO macrophages. We conclude that the role of CLIC1 in macrophage superoxide production is to support redistribution of NADPH oxidase to the plasma membrane, and not through major effects on ERM cytoskeleton or by acting as a plasma membrane chloride channel.

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“…; Casbon et al. ). We assessed subcellular distribution of NOX2 in WT and matched C1KO macrophages (Fig.…”

Section: Resultsmentioning

confidence: 97%

CLIC1 null mice demonstrate a role for CLIC1 in macrophage superoxide production and tissue injury

Ulmasov

Bruno

Oshima

et al. 2017

Physiological Reports

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“…To demonstrate further the involvement of NADPH oxidase in IFNγ-induced ROS production, double immunocytochemical staining showed translocation of p47phox from cytoplasm to membrane and co-localized with the gp91phox after treating cells with IFNγ (Figure 8). In a study with macrophages, IFNγ was shown to activate NADPH oxidase through increase in intracellular trafficking and expression of gp91phox [40]. …”

Section: Discussionmentioning

confidence: 99%

Magnolia polyphenols attenuate oxidative and inflammatory responses in neurons and microglial cells

Chuang

Chan

Zong

et al. 2013

J Neuroinflammation

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BackgroundThe bark of magnolia has been used in Oriental medicine to treat a variety of remedies, including some neurological disorders. Magnolol (Mag) and honokiol (Hon) are isomers of polyphenolic compounds from the bark of Magnolia officinalis, and have been identified as major active components exhibiting anti-oxidative, anti-inflammatory, and neuroprotective effects. In this study, we investigate the ability of these isomers to suppress oxidative stress in neurons stimulated by the ionotropic glutamate receptor agonist N-methyl-D-aspartate (NMDA) and oxidative and inflammatory responses in microglial cells activated by interferon-γ (IFNγ) and lipopolysaccharide (LPS). We also attempt to elucidate the mechanism and signaling pathways involved in cytokine-induced production of reactive oxygen species (ROS) in microglial cells.MethodsDihydroethidium (DHE) was used to assay superoxide production in neurons, while CM-H2DCF-DA was used to test for ROS production in murine (BV-2) and rat (HAPI) immortalized microglial cells. NADPH oxidase inhibitors (for example, diphenyleneiodonium (DPI), AEBSF, and apocynin) and immunocytochemistry targeting p47phox and gp91phox were used to assess the involvement of NADPH oxidase. Western blotting was used to assess iNOS and ERK1/2 expression, and the Griess reaction protocol was employed to determine nitric oxide (NO) concentration.ResultsExposure of Hon and Mag (1–10 μM) to neurons for 24 h did not alter neuronal viability, but both compounds (10 μM) inhibited NMDA-stimulated superoxide production, a pathway known to involve NADPH oxidase. In microglial cells, Hon and Mag inhibited IFNγ±LPS-induced iNOS expression, NO, and ROS production. Studies with inhibitors and immunocytochemical assay further demonstrated the important role of IFNγ activating the NADPH oxidase through the p-ERK-dependent pathway. Hon and, to a lesser extent, Mag inhibited IFNγ-induced p-ERK1/2 and its downstream pathway for ROS and NO production.ConclusionThis study highlights the important role of NADPH oxidase in mediating oxidative stress in neurons and microglial cells and has unveiled the role of IFNγ in stimulating the MAPK/ERK1/2 signaling pathway for activation of NADPH oxidase in microglial cells. Hon and Mag offer anti-oxidative or anti-inflammatory effects, at least in part, through suppressing IFNγ-induced p-ERK1/2 and its downstream pathway.

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“…IFN-γ can regulate NAPDH oxidase activity in different cell types 8 . O 2 - is rapidly converted to H 2 O 2 by spontaneous and enzymatic dismutation.…”

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confidence: 99%

Phagocyte nicotinamide adenine dinucleotide phosphate oxidase activity in patients with inherited IFN-γR1 or IFN-γR2 deficiency

Conti

Aragão-Filho

Prando³

et al. 2015

Journal of Allergy and Clinical Immunology

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Effects of IFN-γ on intracellular trafficking and activity of macrophage NADPH oxidase flavocytochrome b558

Cited by 37 publications

References 55 publications

CLIC1 null mice demonstrate a role for CLIC1 in macrophage superoxide production and tissue injury

CLIC1 null mice demonstrate a role for CLIC1 in macrophage superoxide production and tissue injury

Magnolia polyphenols attenuate oxidative and inflammatory responses in neurons and microglial cells

Phagocyte nicotinamide adenine dinucleotide phosphate oxidase activity in patients with inherited IFN-γR1 or IFN-γR2 deficiency

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