Acute actions of tumor necrosis factor-α on intracellular Ca2+ and K+ currents in human microglia

McLarnon, James G.; Franciosi, Sonia; Wang, X; Bae, Jae Hoon; Choi, Hyun B.; Kim, S.U

doi:10.1016/s0306-4522(01)00119-1

Cited by 44 publications

(40 citation statements)

References 45 publications

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“…The procedures used in Ca 2ϩ -sensitive fluorescence microscopy in this laboratory have been described previously (Khoo et al, 2001;McLarnon et al, 2001). In brief, the fluorescent Ca 2ϩ indicator fura 2-AM was added with pluronic acid (both agents at 1 M) to cultured human microglia bathed in physiological saline solution (PSS) at room temperature for 30 min.…”

Section: Methodsmentioning

confidence: 99%

Modulation of the Purinergic P2X₇Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Choi

Ryu²,

Kim³

et al. 2007

J. Neurosci.

153

119

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We investigated the involvement and roles of the ionotropic purinergic receptor P2X 7 R in microglia in mediating lipopolysaccharide (LPS)-induced inflammatory responses and neuronal damage in rat striatum. A detailed in vivo study showed that LPS injection into striatum markedly increased the expression of P2X 7 R in microglia compared with control (saline)-injected animals. Additionally, LPS injection upregulated a broad spectrum of proinflammatory mediators, including inducible nitric oxide synthase (nitric oxide production marker), 3-nitrotyrosine (peroxynitrite-mediated nitration marker), 4-hydroxynonenal (lipid peroxidation marker), and 8-hydroxy-2Ј-deoxyguanosine (oxidative DNA damage marker), and reduced neuronal viability. The P2X 7 R antagonist oxidized ATP (oxATP) was effective in attenuating expressions of all inflammatory mediators and in addition inhibited LPS-induced activation of the cellular signaling factors p38 mitogen-activated protein kinase and transcriptional factor nuclear factor B.

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Section: Methodsmentioning

confidence: 99%

Modulation of the Purinergic P2X₇Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Choi

Ryu²,

Kim³

et al. 2007

J. Neurosci.

153

119

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“…Ca 2+ spectrofluorometry Some of the procedures used in Ca 2+ -sensitive fluorescence microscopy in this laboratory have been previously described (Wang et al 2000;Khoo et al 2001;McLarnon et al 2001). Cultured human microglia were loaded for 25 min with the Ca 2+ indicator Fura-2 acetoxymethylester (Fura-2/AM).…”

Section: Preparation and Culture Of Human Microgliamentioning

confidence: 99%

Inhibition of lipopolysaccharide‐induced cyclooxygenase‐2, tumor necrosis factor‐α and [Ca²⁺]_i responses in human microglia by the peripheral benzodiazepine receptor ligand PK11195

Choi¹,

Khoo²,

Ryu³

et al. 2002

Journal of Neurochemistry

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The anti-inflammatory actions of the mitochondrial peripheral benzodiazepine receptor (PBR) agonist PK11195 [1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carboxamide] were investigated in human microglia. Application of the microglial inflammatory stimulus lipopolysaccharide (LPS, at 100 ng/mL for 3 h), induced enhancement of the expressions of the inducible enzyme, cyclooxygenase-2 (COX-2) and the pro-inflammatory cytokine, tumor necrosis factor-a (TNF-a). PK11195 (at 50 lM) significantly inhibited the LPSinduced up-regulation of both inflammatory factors; at a lower concentration of PK11195 (2 lM) expression of TNF-a, but not COX-2, was reduced. Production of both factors, using immunocytochemistry for COX-2 and ELISA for TNF-a, was markedly reduced with 50 lM of PK11195 added to LPS solution. Acute application of LPS induced a transient increase in intracellular Ca 2+ [Ca 2+ ] i exhibiting both a slow development and recovery in kinetic behavior. This increase in [Ca 2+ ] i consisted primarily of a Ca 2+ influx component accompanied by a smaller mobilization from intracellular Ca 2+ stores. In the presence of PK11195, the amplitude of the [Ca 2+ ] i response induced by LPS was reduced by 54%. Another mitochondrial agent cyclosporin A (CsA), which also acts at the permeability transition pore (PTP) of mitochondrial membrane but at a site different from the PBR, was ineffective in reducing either the LPS-induced expression of COX-2 and TNF-a or the endotoxin increase in [Ca 2+ ] i . These results indicate that the mitochondrial effector PK11195 is a specific and effective agent for inhibiting LPS-induced microglial expressions of COX-2 and TNF-a and that modulation of Ca 2+ -mediated signaling pathways could be involved in the anti-inflammatory actions. Keywords: cyclooxygenase-2, human microglia, intracellular calcium, lipopolysaccharide, mitochondrial effector, PK11195, tumor necrosis factor-a. Microglia are resident cells of the CNS that serve a functional role as scavenger cells similar to that of peripheral macrophages. These cells have been implicated as key mediators of inflammation in the CNS, during which microglia proliferate and contribute to the inflammatory process by phagocytosis and secretion of cytokines, eicosanoids and other agents (McGeer and McGeer 1995). Although inflammation of the CNS is intended as a homeostatic means to contain damage to neural tissue, such damage may occur from the inflammatory process itself (McGeer and McGeer 1995;Rogers and Griffin 1998). In this case microglial responses to inflammatory stimuli in the brain may actually exacerbate, rather than inhibit, neuronal damage. Abbreviations used: [Ca 2+ ] i , intracellular calcium concentration; COX-2, cyclooxygenase-2; CsA, cyclosporin A; DAPI, 4,6-diaminodino-2-phenylindole; DMEM, Dulbecco's modified Eagle's medium; ER, endoplasmic reticulum; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; LPS, lipopolysaccharide; PBS, phosphate-buffered saline; PBR, peripheral benzodiazepine receptor; PK11195...

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“…The procedures used in Ca 2ϩ -sensitive fluorescence microscopy in this laboratory have been previously described (Wang et al, 2000;Khoo et al, 2001;McLarnon et al, 2001). In brief, the fluorescent Ca 2ϩ indicator fura-2 acetoxymethylester (Fura-2/AM) was added with pluronic acid (both agents at 1 M) to human microglia bathed in physiological saline solution (PSS) at room temperature (20-22°C) for 30 min.…”

Section: Calcium Spectrofluorometrymentioning

confidence: 99%

Differential activation of subtype purinergic receptors modulates Ca²⁺ mobilization and COX‐2 in human microglia

Choi

Hong

Ryu

et al. 2003

Glia

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KEY WORDShuman microglia; adenosine triphosphate; P 2Y and P 2X receptors; COX-2, store-operated channel Ca 2ϩ entry ABSTRACTWe have studied modulation of purinergic receptors (P 2Y and P 2X subtypes) on changes in intracellular Ca 2ϩ [Ca 2ϩ ] i and expression and production of COX-2 in human microglia. Measurements using Ca 2ϩ -sensitive spectrofluorometry showed adenosine triphosphate (ATP) to cause rapid transient increases in [Ca 2ϩ ] i . Application of ATP plus the P 2X antagonist, pyridoxal-phosphate-6-azophenyl-2Ј,4Ј-disulfonic acid (PPADS), or treatment with adenosine diphosphate-␤-S (ADP-␤-S), a selective P 2Y agonist, led to a considerable prolongation in [Ca 2ϩ ] i responses compared with ATP. The prolonged time courses were consistent with sustained activation of store-operated channels (SOC) since SKF96365, an inhibitor of SOC, blocked this component of the response. RT-PCR data showed that microglia expressed no COX-2 either constitutively or following treatment of cells with ATP (100 M for 8 h). However, treatment using ATP plus PPADS or with ADP-␤-S led to marked expression of COX-2. The enhanced COX-2 with ATP plus PPADS treatment was absent in the presence of SKF96365 or using Ca 2ϩ -free solution. Immunocytochemistry, using a specific anti-COX-2 antibody, also revealed a pattern of purinergic modulation whereby lack of P 2X activation enhanced the production of COX-2 protein. These results suggest that modulation of subtypes of purinergic receptors regulates COX-2 in human microglia with a link involving SOCmediated influx of Ca 2ϩ .

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Acute actions of tumor necrosis factor-α on intracellular Ca2+ and K+ currents in human microglia

Cited by 44 publications

References 45 publications

Modulation of the Purinergic P2X₇Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Modulation of the Purinergic P2X₇Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Inhibition of lipopolysaccharide‐induced cyclooxygenase‐2, tumor necrosis factor‐α and [Ca²⁺]_i responses in human microglia by the peripheral benzodiazepine receptor ligand PK11195

Differential activation of subtype purinergic receptors modulates Ca²⁺ mobilization and COX‐2 in human microglia

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Acute actions of tumor necrosis factor-α on intracellular Ca2+ and K+ currents in human microglia

Cited by 44 publications

References 45 publications

Modulation of the Purinergic P2X7Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Modulation of the Purinergic P2X7Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Inhibition of lipopolysaccharide‐induced cyclooxygenase‐2, tumor necrosis factor‐α and [Ca2+]i responses in human microglia by the peripheral benzodiazepine receptor ligand PK11195

Differential activation of subtype purinergic receptors modulates Ca2+ mobilization and COX‐2 in human microglia

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Modulation of the Purinergic P2X₇Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Modulation of the Purinergic P2X₇Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain

Inhibition of lipopolysaccharide‐induced cyclooxygenase‐2, tumor necrosis factor‐α and [Ca²⁺]_i responses in human microglia by the peripheral benzodiazepine receptor ligand PK11195

Differential activation of subtype purinergic receptors modulates Ca²⁺ mobilization and COX‐2 in human microglia