,
* Bonfils Blood Center, and the Departments of
Medicine,
Surgery, and Pediatrics, University of Colorado School of Medicine, Denver
Correspondence: Christopher C. Silliman, M.D., Ph.D., Research Department, Bonfils Blood Center, 717 Yosemite Circle, Denver, CO 80230. E-mail: chistopher.silliman{at}uchsc.edu
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Key Words: inflammation • cytokines • translocation of oxidase components
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
IL-18 is a proinflammatory cytokine with multiple immunomodulating properties [13 14 15 16 17 18 19 20 21 ]. A recent report documented that IL-18 (100 ng/ml) primed formyl-Met-Leu-Phe (fMLP) activation of the reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase of PMNs at 60 min and also caused increased expression of CD11b and release of specific granule components, and was not proapoptotic [22 ]. We hypothesize that IL-18 primes the PMN oxidase at physiologic concentrations and stimulates multiple PMN functions through cellular reorganization of oxidase components and activation of p38 mitogen-activated protein (MAP) kinase, respectively. In the present study, we examined the effects of IL-18 on multiple PMN functions, IL-18-mediated translocation of cytosolic oxidase components (p47phox and p67phox), and IL-18 activation of p38 MAP kinase.
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
PMN isolation and IL-18 priming of the fMLP-activated respiratory burst
PMNs were isolated from healthy human donors by standard techniques [23
]. IL-18 was suspended in saline to working concentrations. The priming activity of IL-18 was measured by incubating PMNs with saline or IL-18 (0.001–100 ng/ml) for 5–60 min at 37°C, followed by activation of the oxidase with saline, 1 µM fMLP, or 200 ng/ml phorbol myristate-13-acetate (PMA). The maximal rate of superoxide anion production was measured by the superoxide dismutase (SOD)-inhibitable reduction of cytochrome c [23
24
25
]. Priming activity was determined as the augmentation, in response to IL-18, of the maximal rate of O2- by fMLP or PMA. To assess synergistic priming with IL-12, PMNs were incubated for 30 min with IL-12 (1 ng/ml) and IL-18 (1 ng/ml), followed by activation with fMLP and measurement of the maximal rate O2-.
Translocation of p47phox and p67phox by digital microscopy
Isolated PMNs were incubated with IL-18 (10–100 ng/ml) or saline controls for 15–60 min, fixed with 4% paraformaldehyde, and smeared onto slides. All manipulations with these slides, unless otherwise indicated, occurred at room temperature. Slides were washed three times with phosphate-buffered saline (PBS), pH 7.4, for 10 min, and the PMNs were porated with 30% acetone, 70% methanol for 3 min. After washing with PBS for 10 min, the slides were blocked with goat serum (the animal vector for the secondary antibody) for 60 min. The serum was replaced with primary antibody to p47phox or p67phox and incubated overnight at 4°C. The slides were washed three times with PBS and then incubated with bis-benzimide, wheat germ agglutinin (WGA), and Cy3-conjugated goat anti-rabbit secondary antibodies for 60 min. The PMNs were washed and mounted in antiquenching media.
The PMNs were imaged at 100x (Zeiss NA1.4, working depth, 2.2 µm), and the data from three epifluorescence channels were digitized on a cooled CCD camera at 1280 x 1024 pixels with 12-bit fidelity. The images were examined to ensure that intensity data were not saturated. Regions of interest, cell body, and cell membrane, were selected by threshold masking on the WGA intensity and by subselection of the highest intensity edge, respectively. The individual cells were separated and counted (submasking), each by total area and membrane area. In each region, area (cellular footprint), mean intensities, and total intensities were calculated for each channel. The data for the two regions of interest (7x2) in each cell (30 PMNs per treatment group) were loaded onto Statview software (4.5; Cupertino, CA) and analyzed by ANOVA for the effect of treatments (control, IL-18, and LPS). Translocation was derived from the membrane enrichment of p47phox or p67phox (total protein staining intensity in the membrane region) relative to the total intensity over the entire cell [26 27 28 ]. Selection of the regions of interest with the intensity of WGA staining for sialo-membranes (FITC channel) removed bias in assessing the integrated intensity of p47phox and p67phox (Cy-3 channel) contained in those regions. PMNs from four healthy donors were treated and processed identically and analyzed as a replicate.
Measurement of CD11b and fMLPr surface expression and changes in PMN size and complexity
PMNs (1x106) were warmed to 37°C and incubated for 30 min with saline or IL-18 (0.01–100 ng/ml), and positive controls consisted of identical PMNs incubated with 200 ng/ml PMA or 1 µM fMLP for 5 min. The PMNs were rapidly cooled to 4°C, and saturating concentrations (1 µg/106 PMNs) of PE-labeled mAb to CD11b or to the fMLPr were added. Following 30 min incubation at 4°C, the PMNs were fixed with paraformaldehyde. CD11b and fMLPr surface expression, cell size, and cell complexity were measured by flow cytometry [23
, 24
, 29
, 30
]. Smears of fixed PMNs incubated with an antibody to the fMLPr were made and examined by digital microscopy.
Determination of elastase release
Elastase release was measured as previously described using 1.5 x 106 PMNs per treatment and an IL-18 incubation of 30 min, followed by activation with buffer or 1 µM fMLP [31
]. Elastase release was reported as the percentage of total cellular elastase as determined by 0.1% Triton X-paired treatment of an identical number of PMNs.
Measurement of activated p38 MAP kinase
PMNs were treated with IL-18 (0.01–100 ng/ml) or saline for 15 s–15 min and immediately placed in Laemmli digestion buffer with freshly prepared protease inhibitors [32
]. The proteins from these lysates were separated by sodium dodecyl sulfate (SDS) gel electrophoresis, transferred to nitrocellulose, and immunoblotted with antibodies to dual-phosphorylated p38 MAP kinase [32
]. The bands of immunoreactivity were visualized using a horseradish peroxidase-labeled secondary antibody and enhanced chemiluminescence. Identical numbers of cell equivalents were used for each treatment as determined by cell counting (Sysmex K-1000, Roche Diagnostics, Indianapolis, IN). As controls, identical lysates were immunoblotted with an antibody to p38 MAP kinase. No differences were observed in the resulting blots, irrespective of treatment group (results not shown).
IL-18-mediated changes in cytosolic Ca2+ concentration
PMN cytosolic Ca2+ levels were determined by indo-1-AM loading of PMNs, washing the PMNs with fresh buffer, and direct measurement over real time as previously reported [24
, 32
, 33
].
Inhibition of IL-18 priming by BAPTA and SB203580
PMNs were pretreated for 15 min at 37°C with dimethyl sulfoxide (DMSO), 50 µM BAPTA-AM, or 1–2.5 µM SB203580. The PMNs were then incubated for 15–30 min with saline or IL-18 (0.01–100 ng/ml) and then activated with 200 ng/ml PMA. The maximum rate of superoxide anion production was measured [23
24
25
, 34
, 35
]. PMA was chosen as the activating agent, as it does not require p38 MAP kinase or changes in cytosolic Ca2+ for activation of the oxidase. BAPTA at 50 µM was used, as this concentration completely chelates the rise in cytosolic Ca2+ in response to fMLP, platelet-activating factor (PAF), or ionomycin [32
].
Statistical analysis
The data are presented as the mean ± SEM. Statistical differences between the groups were determined by a paired ANOVA followed by a Tukey post hoc analysis for multiple comparisons.
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
 View larger version (33K): [in a new window] |
Figure 1. Time- and concentration-dependent IL-18 priming of the fMLP-activated respiratory burst in isolated PMNs. PMNs were incubated with 0.01–100 ng/ml IL-18 for a time course of 5–60 min and activated with 1 µM fMLP, and the maximal rate of superoxide anion production was measured as the SOD-inhibitable reduction of cytochrome c. As compared with saline-treated controls activated with fMLP ( ), priming of the oxidase became significant at 15 min (100 ng/ml,  ; 10 ng/ml,  ), reached a relative maximum at 30 min (100 ng/ml, ; 10 ng/ml, ; 1 ng/ml,  ; 0.1 ng/ml,  ), and decreased for all concentrations at 45 and 60 min of priming, respectively. Each time point represents a sample size of seven separate, healthy donors (*, P<0.05 as compared with buffer-treated PMNs).
|
 View larger version (34K): [in a new window] |
Figure 2. IL-18-mediated translocation of p47phox. PMNs were incubated with saline (Control), IL-18, or LPS for 30 min at 37°C. The PMNs were triple stained with bis-benzimide (blue, nuclear), WGA (green, membrane), and p47phox (red). (A) Representative 100x images of stained PMNs ± the green channel (WGA). IL-18 and LPS caused translocation of the p47phox to the cell membrane, visualized as an increase in a yellow color in the membrane. (B) Data from the PMNs of four separate, healthy donors depicting IL-18- and LPS-induced increases in membrane content of p47phox (integrated intensities as determined by digital-image processing) relative to the content in the same cell, i.e., the cellular translocation of p47phox and the loss of total cellular p47phox in the LPS-treated PMNs. *, Statistical differences (P<0.05) between control and treated PMNs [control (Ctrl), n=32 cells; LPS, n=28 cells; IL-18, n=29 cells].
|
 View larger version (33K): [in a new window] |
Figure 3. IL-18-mediated changes in the cellular location of p67phox. PMNs were incubated with saline (Control), IL-18, or LPS for 30 min at 37°C. The PMNs were triply stained with bis-benzimide (blue, nuclear), WGA (green, membrane), and p67phox (red). (A) Representative 100;tx images of stained PMNs ± the green channel (WGA). LPS but not IL-18 caused translocation of the p67phox to the cell membrane, visualized as an increase in a yellow color in the membrane. (B) Data from the PMNs of four separate, healthy donors depicting LPS-induced increases in membrane content of p67phox (integrated intensities as determined by digital image processing) relative to the content in the same cell, i.e., the cellular translocation. In addition, demonstrated is the loss of total cellular p67phox in LPS-treated PMNs but a relative increase in cellular content of p67phox in response to IL-18 (B). *, Statistical differences (P<0.05) between control and treated PMNs [control (Ctrl), n=24 cells; LPS, n=16 cells; IL-18, n=16 cells].
|
Surface expression of CD11b and the fMLPr and changes in PMN size and complexity
IL-18 elicited changes in CD11b surface expression in a concentration- and time-dependent fashion, paralleling its priming activity (Fig. 1
, Fig. 4
). At 15 min, IL-18 (10 and 100 ng/ml) significantly augmented CD11b surface expression as compared with controls (Fig. 4
; P<0.05). IL-18 concentrations of 0.1–100 ng/ml significantly increased the surface expression of CD11b at 30 min, but only the highest concentration of IL-18 increased CD11b expression at 60 min (P<0.05, n=8; Fig. 4
). IL-18 concentrations of 0.001–0.01 ng/ml did not affect the surface expression of CD11b at any of the incubation times tested (results not shown).
 View larger version (52K): [in a new window] |
Figure 4. IL-18 enhancement of CD11b surface expression on PMNs. PMNs were treated for 5–60 min with IL-18 (0.01–100 ng/ml) or buffer control. Following incubation, the PMNs were rapidly cooled to 4°C, incubated with a PE-labeled mAb to CD11b, and fixed with paraformaldehyde. The amount of surface CD11b was measured by flow cytometry (*, P<0.05 as compared with buffer-treated PMNs). The data in this figure represent the results from six different donors.
|
 View larger version (30K): [in a new window] |
Figure 5. Digital microscopy of IL-18-induced changes in fMLPr expression in PMNs. Isolated PMNs were pretreated with 0.5% DMSO or 2.5 µM SB203580, a specific p38 MAP kinase inhibitor for 15 min at 37°C in low light. The PMNs were then incubated with differing concentrations of IL-18 (0.01–100 ng/ml) for 15 and 30 min at 37°C and were then immediately cooled to 4°C, washed, and incubated for 30 min with a PE-labeled mAb to CD11b at 4°C. The PMNs were then visualized by digital microscopy at 100x. The figure depicts IL-18-mediated changes in the fMLP at 15 min. The figure is representative of three separate experiments from different donors.
|
|
View this table: [in a new window] |
Table 1. IL-18 Induced Changes in fMLPr Surface Expression and PMN Size and Complexity
|
Release of elastase from PMNs exposed to IL-18
A previous report documented that incubation of PMNs with IL-18 caused release of the contents from specific granules [22
]. Because of the importance of the proteases from azurophilic granules, especially elastase, in human disease, we investigated if IL-18 directly caused the release of elastase from isolated PMNs [3
, 31
]. At concentrations of 0.1–10 ng/ml, IL-18 directly caused elastase release from isolated PMNs as compared with vehicle-treated controls (P<0.05), and the amount of elastase released by IL-18 was similar to fMLP-activated PMNs (Table 2
). Concentrations of IL-18 less than 0.1 ng/ml did not yield significant elastase release, and IL-18 did not augment fMLP-mediated release of elastase from PMNs.
|
View this table: [in a new window] |
Table 2. IL-18-Mediated Elastase Release from Isolated PMNs
|
 View larger version (25K): [in a new window] |
Figure 6. IL-18-mediated changes in cytosolic Ca2+. PMNs were loaded with 5 µM indo-1-AM for 10 min at 37°C and washed with fresh, warm KRPD buffer, and the changes in cytosolic Ca2+ in response to IL-18 (0.01–10 ng/ml) were measured in a dual-wavelength spectrofluorimeter. The data represent one of three identical experiments.
|
(TNF-), and other receptor-linked PMN priming agents, we examined IL-18-induced activation of p38 MAP kinase [32
, 43
]. Previous results from this and other laboratories have demonstrated that dual phosphorylation (Thr 180/Tyr 182) is required for p38 MAP kinase activity, and detection of the dual phosphorylated form of p38 MAP kinase correlates with enzyme activity [32
, 43
44
45
]. Therefore, in these experiments, p38 MAP kinase activation was investigated by immunoblotting the separated proteins from whole cell extracts of PMNs incubated with 1 ng/ml IL-18 for 15 s–15 min with an antibody to activated p38 MAP kinase. IL-18 activated p38 MAP kinase at 5 min, which became maximal at 10 min, and a mild decrease was at 15 min (Fig. 7A
). This pattern of p38 MAP kinase activation was identical for all IL-18 concentrations tested that primed the PMN oxidase (0.1–100 ng/ml). The effect of IL-18 on p38 MAP kinase activation was concentration-dependent with a significant activation at 0.1 ng/ml and 1 ng/ml; although a band of activity could be visualized at 10 pg/ml, the densitometry was not statistically different from buffer-treated controls (results not shown; Fig. 7B
). Higher concentrations of IL-18 (10 and 100 ng/ml) also caused activation of p38 MAP kinase at identical time points (results not shown).
 View larger version (51K): [in a new window] |
Figure 7. IL-18-induced p38 MAP kinase activation and the effect of cytosolic Ca2+ chelation. (A) PMNs were treated with 1.0 ng/ml IL-18 or buffer control for 15–900 s. The proteins from the cell lysates were separated by 10% SDS-polyacrylamide gel electrophoresis (PAGE) and were Western blotted with an antibody to active, dual-phosphorylated (Tyr180/Thr182) p38 MAP kinase. The Western blot represents one of three separate experiments. (B) PMNs were treated with IL-18 in concentrations 0.001–1 ng/ml or buffer for 10 min. The proteins from the cell lysates were separated by 10% SDS-PAGE and immunoblotted with an antibody to activated, dual-phosphorylated (Tyr180/Thr182) p38 MAP kinase. The Western blot represents one of four separate experiments. (C) PMNs were pretreated with DMSO or 50 µM BAPTA (B) for 15 min at 37°C and then incubated with IL-18 (0.1–1.0 ng/ml) for 10 min. The PMNs were extracted, and the proteins were separated by SDS-PAGE. The proteins were transferred to nitrocellulose and immunoblotted with an antibody to active, dual-phosphorylated (Tyr180/Thr182) p38 MAP kinase. These data are representative of two identical experiments.
|
The effect of p38 MAP kinase inhibition on IL-18-mediated priming of the PMN oxidase and changes in fMLPr expression
As IL-18 caused activation of p38 MAP kinase, we tested the ability of the specific p38 MAP kinase inhibitor SB203580 (2.5 µM) on IL-18 priming of the respiratory burst and IL-18-mediated increases in fMLPr surface expression [34
, 35
, 46
]. In the oxidase experiments, 200 ng/ml PMA was used as the activator of the oxidase, as PMA-mediated oxidase assembly does not require activation of p38 MAP kinase [32
]. IL-18 primed the PMA-activated respiratory burst by 1.3- to 2.0-fold as compared with saline-primed, PMA-activated PMNs (n=15, P<0.05; Table 3
). Pretreatment of PMNs with SB203580 (2.5 µM) inhibited IL-18 priming (10–100 ng/ml) at 15 min by 82±7% and 100±10% (n=6 for all groups; P<0.05; results not shown), and at 30 min, SB203580 inhibited IL-18 priming (0.1–100 ng/ml) of PMA activation by 88 ± 12% to 97 ± 4% (n=5 for all groups; P<0.05). In analogous experiments, SB203580 (2.5 µM) inhibited IL-18-mediated up-regulation ofthe fMLPr, visually (Fig. 5)
and by flow cytometry (54±8% to 73±9%) at the 10 ng/ml and 100 ng/ml IL-18 concentrations, respectively.
|
View this table: [in a new window] |
Table 3. SB203580 and BAPTA Inhibition of IL-18 Priming of the PMA-Activated Respiratory Burst
|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
(IFN-) production in natural killer cells and T lymphocytes [14
, 15
, 17
18
19
, 21
, 39
]. These studies focused on IL-18 induction of IFN- and its role in host defense [14
, 15
, 17
18
19
, 21
, 39
]. Moreover, IL-18 appeared to effectively stimulate lymphocytes in the picomolar range, as a single agent or as a cofactor [14
, 15
, 17
18
19
, 21
, 39
]. In addition, bacterial infections, especially Mycobacterium tuberculosis, resulted in significant increases of IL-18 in vivo [19
]. From animal data and clinical cases of sepsis and acute lung injury, increased levels of IL-18 appeared to correlate with tissue injury/inflammation [7
, 8
, 13
, 20
, 47
]. The data presented in this report arose from the hypothesis that physiologic concentrations of IL-18 would stimulate PMNs to facilitate their emigration from the vasculature and augment their microbicidal activity. Distinct from previous work, this report documented that IL-18 caused translocation of the cytosolic protein p47phox to the cell membrane, which appeared to correlate with the observed time course of IL-18-priming activity. Furthermore, LPS also caused similar translocation of the p47phox to the membrane, despite the observed loss of p47phox. This loss of p47phox was presumably a result of membrane secretion and was supported by the loss of WGA staining in LPS-treated PMNs (data not shown). However, LPS also caused translocation of p67phox to the PMN membrane contrary to a previous report [40 ]. Such differences may have been a result of the distinct methods used. First, the present study used LPS concentrations of 2 µg/ml, tenfold higher than the previous study. Second, the present study used an LPS incubation time of 30 min not 60–70 min as used by the previous study. Finally, the present study used fixed, porated PMNs for digital microscopy, whereas the previous studies used immunoblots of subcellular fractions separated by gradient centrifugation [40 ]. Digital microscopy is a well-accepted method of quantifying the cellular locality and content of a number of proteins, requires fewer cells for study, and may be more desirable for some studies because it does not destroy the cellular architecture [26 27 28 ]. Despite the observed differences, both studies implicated a role for LPS-mediated translocation of p47phox to the membrane; moreover, the current study demonstrated an identical role of p47phox translocation in IL-18 priming of the NADPH oxidase [40 ].
The data presented support the hypothesis that IL-18 affected the following PMN functions: oxidase activation, chemotaxis, and azurophilic granule release at concentrations found in septic patients. Furthermore, IL-18 caused changes in PMN size but not cellular complexity, similar to PMA and fMLP. IL-18 also primed the oxidase and stimulated PMN chemotaxis (CD11b expression) in a shorter time course than previously reported (15–30 min vs. 60 min). IL-18 priming of the NADPH oxidase and stimulation of other PMN functions (15–30 min) were similar to other physiologic priming agents, including IL-1ß (5–30 min), LPS (20–60 min), and TNF- (5–60 min) [36
, 38
, 48
49
50
]. However, IL-18 activation of PMNs differed from TNF- and IL-1ß by its ability to cause a modest release of elastase [36
, 38
, 48
49
50
]. Common PMN activation profiles by IL-18 and IL-1ß would be expected as a result of their structural similarities, for both cytokines are primarily all ß-pleated, sheet-folded molecules and, more importantly, because of the structural similarities of the receptors, which have a common, intracellular domain [39
, 51
, 52
]. Such comparable activity for IL-18 and IL-1ß has previously been reported in lymphocytes [39
]. In addition, unlike lymphocytes, coincubation of PMNs with IL-12 did not potentiate the effects of IL-18 [53
]. These results were surprising, as granulocytes express the IL-12 receptor, and IL-12 has been reported to affect PMN proinflammatory function [54
, 55
]. Thus, it appeared that the observed effects on PMNs were a result of IL-18 alone and not secondary to synergistic action with IL-12.
From investigation of IL-18 signaling, we demonstrated that IL-18 activated p38 MAP kinase in a Ca2++-dependent manner. This p38 MAP kinase activation was directly influenced by the IL-18 concentration and the incubation time, with maximal activity occurring at 10 min. Previous work from this laboratory has demonstrated that dual phosphorylation of p38 MAP kinase signifies p38 MAP kinase activation, further supported by specific in vitro phosphorylation of activating transcription factor-2 [32
]. In addition, the inhibition of active p38 MAP kinase by SB 203580 or the inhibition of Ca2+-dependent MAP kinase activation with BAPTA directly influenced PMN function. As compared with TNF- and LPS, both of which require p38 MAP kinase for maximal priming activity, IL-18 activated p38 MAP kinase earlier than LPS (5–10 min vs. 20 min) and was similar to TNF- (10 min) [43
, 45
]. Investigation of IL-18 signal transduction also demonstrated that IL-18 directly caused changes in cytosolic Ca2+ similar to IL-1ß [37
]. This increase in cytosolic Ca2+ was required for p38 MAP kinase activation, and such Ca2+-dependent activation of p38 MAP kinase has been shown for other receptor-linked chemoattractants [32
]. Furthermore, only those concentrations of IL-18 that affected PMN physiology elicited significant activation of p38 MAP kinase.
In conclusion, at physiologic concentrations, IL-18 stimulated PMNs through Ca2+-dependent activation of p38 MAP kinase. Increased levels of IL-18 have been associated with models of traumatic injury, human sepsis, and clinical acute lung injury, a syndrome of PMN-mediated organ injury [8 , 13 , 47 ]. Thus, IL-18 may be involved in syndromes of PMN-elicited organ injury; however, further studies are required to delineate the role of this cytokine in normal PMN physiology and syndromes of PMN-mediated organ injury [56 57 58 59 ].
Received August 27, 2001; revised March 27, 2002; accepted March 29, 2002.
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
This article has been cited by other articles:
 |
|
 |
|
  C. C. Silliman, M. R. Kelher, F. Gamboni-Robertson, C. Hamiel, K. M. England, C. A. Dinarello, T. H. Wyman, S. Y. Khan, N. J. D. McLaughlin, R. S. Bercovitz, et al. Tumor necrosis factor-{alpha} causes release of cytosolic interleukin-18 from human neutrophils Am J Physiol Cell Physiol, March 1, 2010; 298(3): C714 - C724. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Akhtar, X. Li, I. H. Chaudry, and M. A. Choudhry Neutrophil chemokines and their role in IL-18-mediated increase in neutrophil O2- production and intestinal edema following alcohol intoxication and burn injury Am J Physiol Gastrointest Liver Physiol, August 1, 2009; 297(2): G340 - G347. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Venkatesan, A. J. Valente, V. S. Reddy, D. A. Siwik, and B. Chandrasekar Resveratrol blocks interleukin-18-EMMPRIN cross-regulation and smooth muscle cell migration Am J Physiol Heart Circ Physiol, August 1, 2009; 297(2): H874 - H886. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Venkatachalam, S. D. Prabhu, V. S. Reddy, W. H. Boylston, A. J. Valente, and B. Chandrasekar Neutralization of Interleukin-18 Ameliorates Ischemia/Reperfusion-induced Myocardial Injury J. Biol. Chem., March 20, 2009; 284(12): 7853 - 7865. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. F. Fortin, T. Ear, and P. P. McDonald Autocrine role of endogenous interleukin-18 on inflammatory cytokine generation by human neutrophils FASEB J, January 1, 2009; 23(1): 194 - 203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. J. D. McLaughlin, A. Banerjee, S. Y. Khan, J. L. Lieber, M. R. Kelher, F. Gamboni-Robertson, F. R. Sheppard, E. E. Moore, G. W. Mierau, D. J. Elzi, et al. Platelet-Activating Factor-Mediated Endosome Formation Causes Membrane Translocation of p67phox and p40phox That Requires Recruitment and Activation of p38 MAPK, Rab5a, and Phosphatidylinositol 3-Kinase in Human Neutrophils J. Immunol., June 15, 2008; 180(12): 8192 - 8203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Westermann, S. Van Linthout, S. Dhayat, N. Dhayat, F. Escher, C. Bucker-Gartner, F. Spillmann, M. Noutsias, A. Riad, H.-P. Schultheiss, et al. Cardioprotective and Anti-Inflammatory Effects of Interleukin Converting Enzyme Inhibition in Experimental Diabetic Cardiomyopathy Diabetes, July 1, 2007; 56(7): 1834 - 1841. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Bachmann, C. Dragoi, M. A. Poleganov, J. Pfeilschifter, and H. Muhl Interleukin-18 directly activates T-bet expression and function via p38 mitogen-activated protein kinase and nuclear factor-{kappa}B in acute myeloid leukemia-derived predendritic KG-1 cells Mol. Cancer Ther., February 1, 2007; 6(2): 723 - 731. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Li, S. N. Rana, M. G. Schwacha, I. H. Chaudry, and M. A. Choudhry A novel role for IL-18 in corticosterone-mediated intestinal damage in a two-hit rodent model of alcohol intoxication and injury J. Leukoc. Biol., August 1, 2006; 80(2): 367 - 375. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. R. Sheppard, M. R. Kelher, E. E. Moore, N. J. D. McLaughlin, A. Banerjee, and C. C. Silliman Structural organization of the neutrophil NADPH oxidase: phosphorylation and translocation during priming and activation J. Leukoc. Biol., November 1, 2005; 78(5): 1025 - 1042. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. R. Woldbaek, J. B. Sande, T. A. Stromme, P. K. Lunde, S. Djurovic, T. Lyberg, G. Christensen, and T. Tonnessen Daily administration of interleukin-18 causes myocardial dysfunction in healthy mice Am J Physiol Heart Circ Physiol, August 1, 2005; 289(2): H708 - H714. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Chandrasekar, S. Mummidi, A. J. Valente, D. N. Patel, S. R. Bailey, G. L. Freeman, M. Hatano, T. Tokuhisa, and L. E. Jensen The Pro-atherogenic Cytokine Interleukin-18 Induces CXCL16 Expression in Rat Aortic Smooth Muscle Cells via MyD88, Interleukin-1 Receptor-associated Kinase, Tumor Necrosis Factor Receptor-associated Factor 6, c-Src, Phosphatidylinositol 3-Kinase, Akt, c-Jun N-terminal Kinase, and Activator Protein-1 Signaling J. Biol. Chem., July 15, 2005; 280(28): 26263 - 26277. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. N. Rana, X. Li, I. H. Chaudry, K. I. Bland, and M. A. Choudhry Inhibition of IL-18 reduces myeloperoxidase activity and prevents edema in intestine following alcohol and burn injury J. Leukoc. Biol., May 1, 2005; 77(5): 719 - 728. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Elbim, C. Guichard, P. M. C. Dang, M. Fay, E. Pedruzzi, H. Demur, C. Pouzet, J. El Benna, and M.-A. Gougerot-Pocidalo Interleukin-18 Primes the Oxidative Burst of Neutrophils in Response to Formyl-Peptides: Role of Cytochrome b558 Translocation and N-Formyl Peptide Receptor Endocytosis Clin. Vaccine Immunol., March 1, 2005; 12(3): 436 - 446. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Chandrasekar, S. Mummidi, W. C. Claycomb, R. Mestril, and M. Nemer Interleukin-18 Is a Pro-hypertrophic Cytokine That Acts through a Phosphatidylinositol 3-Kinase-Phosphoinositide-dependent Kinase-1-Akt-GATA4 Signaling Pathway in Cardiomyocytes J. Biol. Chem., February 11, 2005; 280(6): 4553 - 4567. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-K. Lee, S.-H. Kim, E. C. Lewis, T. Azam, L. L. Reznikov, and C. A. Dinarello Differences in signaling pathways by IL-1{beta} and IL-18 PNAS, June 8, 2004; 101(23): 8815 - 8820. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Chandrasekar, K. Vemula, R. M. Surabhi, M. Li-Weber, L. B. Owen-Schaub, L. E. Jensen, and S. Mummidi Activation of Intrinsic and Extrinsic Proapoptotic Signaling Pathways in Interleukin-18-mediated Human Cardiac Endothelial Cell Death J. Biol. Chem., May 7, 2004; 279(19): 20221 - 20233. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Bellocchio, C. Montagnoli, S. Bozza, R. Gaziano, G. Rossi, S. S. Mambula, A. Vecchi, A. Mantovani, S. M. Levitz, and L. Romani The Contribution of the Toll-Like/IL-1 Receptor Superfamily to Innate and Adaptive Immunity to Fungal Pathogens In Vivo J. Immunol., March 1, 2004; 172(5): 3059 - 3069. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. M. Hillyer and B. Woodward Interleukin-10 concentration determined by sandwich enzyme-linked immunosorbent assay is unrepresentative of bioactivity in murine blood Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2003; 285(6): R1514 - R1519. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
