Secretory Phospholipases A2 Induce β-Glucuronidase Release and IL-6 Production from Human Lung Macrophages

Triggiani, Massimo; Granata, Francescopaolo; Oriente, Alfonso; Marino, V. De; Gentile, Marco; Calabrese, Cecilia; Palumbo, Cristiana; Marone, Gianni

doi:10.4049/jimmunol.164.9.4908

Cited by 87 publications

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“…␤-Glucuronidase release in cell-free supernatants or in cell lysates was measured by a colorimetric assay (28). Briefly, 200 l of supernatants or 100 l of cell lysates was incubated (37°C, 18 h) with 400 l of 0.1 M acetate buffer, pH 4.5, containing 1 mol of phenolphthalein glucuronide.…”

Section: ␤-Glucuronidase Assaymentioning

confidence: 99%

Histamine Induces Exocytosis and IL-6 Production from Human Lung Macrophages Through Interaction with H1 Receptors

Triggiani

Gentile

Secondo

et al. 2001

The Journal of Immunology

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135

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Increasing evidence suggests that a continuous release of histamine from mast cells occurs in the airways of asthmatic patients and that histamine may modulate functions of other inflammatory cells such as macrophages. In the present study histamine (10−9–10−6 M) increased in a concentration-dependent fashion the basal release of β-glucuronidase (EC50 = 8.2 ± 3.5 × 10−9 M) and IL-6 (EC50 = 9.3 ± 2.9 × 10−8 M) from human lung macrophages. Enhancement of β-glucuronidase release induced by histamine was evident after 30 min and peaked at 90 min, whereas that of IL-6 required 2–6 h of incubation. These effects were reproduced by the H1 agonist (6-[2-(4-imidazolyl)ethylamino]-N-(4-trifluoromethylphenyl)heptane carboxamide but not by the H2 agonist dimaprit. Furthermore, histamine induced a concentration-dependent increase of intracellular Ca2+ concentrations ([Ca2+]i) that followed three types of response, one characterized by a rapid increase, a second in which [Ca2+]i displays a slow but progressive increase, and a third characterized by an oscillatory pattern. Histamine-induced β-glucuronidase and IL-6 release and [Ca2+]i elevation were inhibited by the selective H1 antagonist fexofenadine (10−7–10−4 M), but not by the H2 antagonist ranitidine. Inhibition of histamine-induced β-glucuronidase and IL-6 release by fexofenadine was concentration dependent and displayed the characteristics of a competitive antagonism (Kd = 89 nM). These data demonstrate that histamine induces exocytosis and IL-6 production from human macrophages by activating H1 receptor and by increasing [Ca2+]i and they suggest that histamine may play a relevant role in the long-term sustainment of allergic inflammation in the airways.

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Section: ␤-Glucuronidase Assaymentioning

confidence: 99%

Histamine Induces Exocytosis and IL-6 Production from Human Lung Macrophages Through Interaction with H1 Receptors

Triggiani

Gentile

Secondo

et al. 2001

The Journal of Immunology

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135

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“…These include the release of preformed granule proteins (exocytosis) [26,42] and the production of proinflammatory cytokines and chemokines [42][43][44][45]. Therefore, we evaluated the effects of Na 1 -free medium on the release of b-glucuronidase -a lysosomal enzyme used as a marker of exocytosis [42,46] -from HLM. Figure 7 shows that incubation of HLM with the Na 1 -free medium for 4 h did not influence the basal release of b-glucuronidase, whereas a secretory phospholipase A 2 (sPLA 2 ), used as a positive control [46], induced its release from HLM.…”

Section: Effect Of Cb-dmb On the [Ca 21 ] I Increase Induced By Histamentioning

confidence: 99%

“…b-Glucuronidase release in cell-free supernatants or in cell lysates was measured by a colorimetric assay [46]. Briefly, 100 mL of supernatant or cell lysate were incubated (371C, 18 h) with 200 mL of 0.1 M acetate buffer, pH 4.5, containing 1 mmol of phenolphthalein glucuronide.…”

Section: B-glucuronidasementioning

confidence: 99%

“…Therefore, we evaluated the effects of Na 1 -free medium on the release of b-glucuronidase -a lysosomal enzyme used as a marker of exocytosis [42,46] -from HLM. Figure 7 shows that incubation of HLM with the Na 1 -free medium for 4 h did not influence the basal release of b-glucuronidase, whereas a secretory phospholipase A 2 (sPLA 2 ), used as a positive control [46], induced its release from HLM. The lack of effect on exocytosis was not due to Na 1 removal because stimulation of HLM with sPLA 2 in Na-free 1 medium induced b-glucuronidase release comparable to that induced by sPLA 2 in Na 1 -containing medium (Fig.…”

mentioning

confidence: 99%

“…At the end of incubation, the supernatant was collected and centrifuged (1000g, 41C, 5 min). b-Glucuronidase release was determined using a colorimetric technique [46]. The values are expressed as a percentage of the total cellular content determined in cell aliquots lysed with 0.1% Triton X-100.…”

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Expression and function of Na⁺/Ca²⁺ exchangers 1 and 3 in human macrophages and monocytes

et al. 2009

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The Na 1 /Ca 21 exchanger (NCX) is a membrane transporter that can switch Na 1 and Ca 21 in either direction to maintain the homeostasis of intracellular Ca 21 . Three isoforms (NCX1, NCX2, and NCX3) have been characterized in excitable cells, e.g. neurons and muscle cells. We examined the expression of these NCX isoforms in primary human lung macrophages (HLM) and blood monocytes. NCX1 and NCX3, but not NCX2, are expressed in HLM and monocytes at both mRNA and protein levels. Na 1 -free medium induced a significant increase in intracellular calcium concentration ([Ca 21 ] i ) in both cell types. This response was completely abolished by the NCX inhibitor 5-(N-4-chlorobenzyl)-20,40-dimethylbenzamil (CB-DMB). Moreover, inhibition of NCX activity during Ca 21 -signaling induced by histamine caused a delay in restoring baseline [Ca 21 ] i . Na 1 -free medium induced TNF-a expression and release in HLM comparable to that caused by LPS. TNF-a release induced by Na 1 -free medium was blocked by CB-DMB and greatly reduced by RNAi-mediated knockdown of NCX1. These results indicate that human macrophages and monocytes express NCX1 and NCX3 that operate in a bidirectional manner to restore [Ca 21 ] i , to generate Ca 21 -signals, and to induce TNF-a production. Therefore, NCX may contribute to regulate Ca 21 homeostasis and proinflammatory functions in human macrophages and monocytes.Key words: Ca 21 -signaling . Macrophages . Monocytes . Na 1 /Ca 21 exchanger IntroductionThe Na 1 /Ca 21 exchanger (NCX) is a plasma membrane protein involved in the homeostasis of intracellular Ca 21 [1]. NCX is a bidirectional ion transporter that catalyzes the exchange of Na 1 and Ca 21 depending on their electrochemical gradients [2]. Under physiological conditions, NCX's primary role is to extrude Ca 21 from cells using the Na 1 gradient across the cell membrane (forward mode of operation) [3]. However, in some cases it can contribute to the Ca 21 influx into the cells by working in the reverse mode (i.e. coupling Ca 21 influx with Na 1 efflux) [4][5][6].Three isoforms of NCX, NCX1, NCX2, and NCX3 have been cloned in mammals, outlining a multigene family whose members share a similar molecular structure [7]. NCX is modeled with nine transmembrane segments involved in ion transport and a long central cytoplasmic loop that has regulatory functions [8]. However, truncated forms lacking certain transmembrane segments, but still possessing NCX activity, have also been Eur. J. Immunol. 2009. 39: 1405-1418 DOI 10.1002 Leukocyte signaling 1405 described as the result of alternative splicing of the three genes [9][10][11]. NCX1 is largely predominant in mammalian tissues such as heart, brain, and kidney while the expression of NCX2 and NCX3 appears to be limited to the brain and skeletal muscle [7]. NCX is a key element regulating intracellular Ca 21 concentrations ([Ca 21 ] i ) in many excitable cells, including myocardiocytes, retinal rod photoreceptors, smooth muscle cells, and neurons [3]. Non-excitable cells such as renal epithelial ce...

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Group IIA secretory phospholipase A2 stimulates inducible nitric oxide synthase expression via ERK and NF-κB in macrophages

et al. 2001

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Secretory Phospholipases A2 Induce β-Glucuronidase Release and IL-6 Production from Human Lung Macrophages

Cited by 87 publications

References 59 publications

Histamine Induces Exocytosis and IL-6 Production from Human Lung Macrophages Through Interaction with H1 Receptors

Histamine Induces Exocytosis and IL-6 Production from Human Lung Macrophages Through Interaction with H1 Receptors

Expression and function of Na⁺/Ca²⁺ exchangers 1 and 3 in human macrophages and monocytes

Group IIA secretory phospholipase A2 stimulates inducible nitric oxide synthase expression via ERK and NF-κB in macrophages

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Secretory Phospholipases A2 Induce β-Glucuronidase Release and IL-6 Production from Human Lung Macrophages

Cited by 87 publications

References 59 publications

Histamine Induces Exocytosis and IL-6 Production from Human Lung Macrophages Through Interaction with H1 Receptors

Histamine Induces Exocytosis and IL-6 Production from Human Lung Macrophages Through Interaction with H1 Receptors

Expression and function of Na+/Ca2+ exchangers 1 and 3 in human macrophages and monocytes

Group IIA secretory phospholipase A2 stimulates inducible nitric oxide synthase expression via ERK and NF-κB in macrophages

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Expression and function of Na⁺/Ca²⁺ exchangers 1 and 3 in human macrophages and monocytes