| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* Graduate School of Biotechnology, Korea University, Anam-dong, Seoul, Korea;
Department of Life Science, Kwangju Institute of Science and Technology, Kwangju, Korea; and
Department of Oncology/Hematology, Ewha Woman’s University, College of Medicine, Seoul, Korea
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
45% amino acid identity with BLT1 (5, 6, 7). Neutrophils are the primary targets of LTB4, and their recruitment to sites of inflammation is one of the principal ways in which LTB4 contributes to inflammatory responses. In particular, the influx of neutrophils into the airway is a common feature of several inflammatory diseases, including acute bronchitis, adult respiratory distress syndrome (ARDS), and chronic obstructive pulmonary disease (COPD) (8, 9), as well as severe asthma (10, 11). Once leukocytes are beyond the endothelial barrier, chemotactic signals frequently lead to their accumulation near mucosal epithelial cells and in the lumen of the airway. Airway epithelial cells may thus be important regulators not only of retention and activation of leukocytes, but also of their passage into the airway itself. It has therefore been suggested that LTB4-induced transepithelial migration of neutrophils plays a crucial role in the pathogenesis of ARDS, COPD, and severe asthma. Yet despite this implication, the signaling pathway via which LTB4 mediates transepithelial migration of neutrophils remains largely unknown.
In the present study, therefore, we investigated the signaling pathway by which LTB4 induces transepithelial migration of neutrophil-like granulocytes (differentiated HL-60 neutrophils (dHL-60)) differentiated from HL-60 cells, which have been shown to be a valid model system for the analysis of human neutrophilic migration and chemotaxis (12), and by human polymorphonuclear neutrophils (PMNs) isolated from healthy volunteers. Our results indicate that LTB4-induced transepithelial migration is accomplished via an ROS-extracellular signal-regulated kinase (ERK)-linked pathway. In addition, the physiological relevance of this pathway was validated in vivo by demonstrating that ROS generation and ERK activation are both required for transmigration of peripheral blood neutrophils across the airway epithelium of BALB/c mice.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
2',7'-Dichlorofluorescin diacetate (DCFDA) was purchased from Molecular Probes (Eugene, OR). LTB4APA, LY1718, genistein, and AACOCF3 were obtained from Biomol (Plymouth Meeting, PA). LTB4 and U75302 were purchased from Cayman Chemical Co. (Ann Arbor, MI). BSA, DMSO, PMA, GF109203X, wortmannin, diphenylene iodonium (DPI), and N-acetylcysteine (NAC) were obtained from Sigma-Aldrich (St. Louis, MO). FBS, DMEM, phenol red-free DMEM, gentamicin, and nonessential amino acids were purchased from Life Technologies (Gaithersburg, MD). All other chemicals were obtained from standard sources and were molecular biology grade or higher.
Cell culture and differentiation
Human promyelocytic HL-60 cells obtained from American Type Culture Collection (Manassas, VA; CCL-240) were grown in RPMI 1640 medium supplemented with 10% heat-inactivated FBS, 0.1 mM nonessential amino acids, 50 U/ml penicillin, and 50 µg/ml streptomycin at 37°C under a humidified 95%/5% (v/v) mixture of air and CO2. To induce cells to undergo differentiation along the neutrophil lineage, aliquots of HL-60 cell suspension (5 x 105 cells/ml) were seeded onto dishes and grown for 5 days in the absence or the presence of 1.25% DMSO. Cell differentiation was then evaluated using four criteria (13, 14, 15): 1) morphological changes (nuclear segmentation and granules formation) were analyzed microscopically using H&E cytochemical staining; 2) cell proliferation was assayed with 0.4% trypan blue exclusion; 3) the capacity to reduce nitro blue tetrazolium, a property associated with myeloid cell maturation, was determined spectrophotometrically at 540 nm; and 4) surface expression of differentiation-related Ags was evaluated by flow cytometry using FITC-conjugated mAbs against CD11b, CD16, and CD33. A549 human lung epithelial cells were grown in RPMI containing 10% FBS, 0.1 mM nonessential amino acids, 50 U/ml penicillin, and 100 µg/ml streptomycin. Human PMNs were isolated from blood samples collected from healthy volunteers in heparin sodium salt (100 U; Sigma-Aldrich; H-3149). PMNs were separated on a Ficoll-Paque density gradient (1.077 ± 0.001 g/ml), followed by 2% dextran sedimentation to remove the majority of RBCs (Amersham Pharmacia Biotech, Uppsala, Sweden). Any remaining RBCs were lysed in 0.15 M ammonium chloride solution. The remaining PMNs were suspended in RPMI and used for transepithelial migration assays.
Transepithelial migration assays
Transepithelial migration assays were conducted as previously described (8). Briefly, a collagen-coated, polycarbonate filter insert (5-µm pore size) was placed inside each well of several Transwell 12-well tissue culture plates to create a well within a well, after which 5.2 ml of medium was added to completely submerge the insert. Using sterilized forceps, the insert was then inverted, ensuring that no air bubbles were trapped under it, and exactly 0.8 ml of medium was removed from each well. The insert was then moved to the center of its well to avoid an overlapping meniscus at the edge. Each inverted insert was then gently seeded with a total of 0.5 x 106 A549 cells in two 50-µl aliquots of cell suspension, yielding a configuration in which the cells were growing on the microporous membrane with air above and medium below. The plates were then incubated at 37°C under a 5% CO2 atmosphere for 4–5 days, at which time the inserts were returned to their original orientation for the transmigration experiments. For experimentation, HL-60 cells or PMNs were seeded into the upper chambers of the Transwell system to a density of 5 x 105/well, and the indicated concentrations of LTB4 or saline were added to the lower chambers. After incubating at 37°C in 95%/5% (v/v) mixture of air and CO2 for 6 h, the amount of basal to apical transepithelial migration of dHL-60 or human PMNs was determined by counting the migrated cells on the underside of the insert. When assessing the effects of inhibitors, cells were pretreated with the inhibitor of interest for 20 min before the addition of LTB4.
Measurement of intracellular H2O2
Intracellular H2O2 was measured as a function of DCF fluorescence using a fluorometer. Briefly, HL-60 cells were grown for 5 days in the presence of 1.25% DMSO and then were serum-starved for 6 h in phenol-red free RPMI supplemented 0.5% FBS. To measure intracellular H2O2, cells were then incubated for 10 min with the H2O2-sensitive fluorophore DCFDA (5 µg/ml), which, when taken up, fluorescently labels intracellular H2O2 with DCF. After incubation with DCFDA, cells were exposed to LTB4 or PMA for 5 min and immediately observed under a fluorometer from Molecular Devices (SpectraMAX GeminiXS; Sunnyvale, CA). DCF fluorescence was excited at 488 nm, and the evoked emission was filtered with a 515-nm long-pass filter.
SDS-PAGE and immunoblot analysis
Protein samples were heated at 95°C for 5 min and then subjected by SDS-PAGE on 10% acrylamide gels, followed by transfer to polyvinylidene difluoride membranes using a wet transfer unit (NOVEX, San Diego, CA; for 2 h at 100 V). The membranes were then blocked for 1 h with TBS containing 0.05% (v/v) Tween 20 plus 5% (w/v) nonfat dry milk and incubated, first for 2 h with the primary Ab (1/2000 dilutions of anti-phospho-ERK or anti-p38) in TBS containing 0.05% (v/v) Tween 20 plus 3% (w/v) BSA, and then for 1 h with HRP-conjugated secondary Ab. The bands were developed using an ECL kit and were visualized on XAR-5 film (Eastman Kodak, Rochester, NY).
RNA isolation and RT-PCR
Total cellular RNA was extracted from dHL-60 cells using RNAzol B (Tel-Test, Friendswood, TX), dissolved in diethylpyrocarbonate-treated water, and quantified by UV scanning. One microgram of the extracted RNA was then reverse transcribed by incubating it for 60 min at 37°C in 20 µl in buffer containing 10 mM Tris (pH 8.3); 50 mM KCl; 5 mM MgCl2; 1 mM each of dATP, dCTP, dGTP, and dTTP; and oligo(dT) primers. Hot-start PCR was used to increase the specificity of the amplification with specific primers for human BLT1 (sense, 5'-TATGTCTGCGGAGTCAGCATGTACGC; antisense, 5'-CCTGTAGCCGACGCCCTATGTCCG), human BLT2 (sense, 5'-AGCCTGGAGACTCTGACCGCTTTCG; antisense, 5'-GACGTAGAGCACCGGGTTGACGCTA), and human GAPDH (15). The PCR protocol entailed 25 cycles of denaturation at 94°C for 30 s and elongation at 68°C for 2 min in a Mygenie Thurmal Block from Bioneer (Taejon, Korea). The amplified products were subjected to electrophoresis on 1.8% agarose gels, after which the bands were visualized by ethidium bromide staining and photographed using Polaroid 667 film (Cambridge, MA).
Transient transfection and luciferase assay
Transient transfection was conducted by plating 2 x 105 cells in 60-mm dishes and then adding Lipofectamine Plus/DNA complex prepared with 1.8 µg of DNA/dish. To control for variations in cell number and transfection efficiency, all clones were cotransfected with 0.4 µg of pSV40-
GAL, a eukaryotic expression vector containing the Escherichia coli -galactosidase (lacZ) structural gene under transcriptional control of the SV40 promoter. The amount of DNA used in each transfection was held constant (1.8 µg) by adding sonicated calf thymus DNA. To measure ERK’s kinase activity using a PathDetect trans-reporting system (catalog no. 219005; Stratagene, La Jolla, CA), Elk1 fused to trans-activator plasmid was cotransfected with pFR-Luc reporter plasmid according to the manufacturer’s protocol. After incubating for 3 h with the Lipofectamine Plus/DNA complex, the cells were rinsed with serum-free medium and incubated in fresh RPMI 1640 supplemented with 10% FBS for an additional 24 h. The cells in each dish were then treated with LTB4 or control buffer for 6 h, after which they were harvested, lysed in 0.1 ml of lysis solution (0.2 M Tris-Cl (pH 7.6) and 0.1% Triton X-100), and spun for 1 min. The resultant supernatants were assayed for protein and -galactosidase activity. Luciferase activity was assayed in 10-µl samples of extract. Luciferase luminescence was counted in a luminometer (Turner Design, Sunnyvale, CA; TD-20/20) and normalized to cotransfected -galactosidase activity (16). Transfection experiments were performed in triplicate using two independently isolated sets of cells, and the results were averaged.
LTB4-challenged mouse model
Pathogen-free female BALB/c mice (8 wk old) were purchased from the Korea Research Institute of Chemistry Technology (Daejon, Korea). The mice were housed throughout the experiments in a laminar flow cabinet and were provided with standard laboratory chow and water ad libitum. For intratracheal administration, mice were anesthetized by i.p. injection of 150 µl of saline containing 13 mg/ml ketamine HCl (Yuhan, Seoul, Korea) and 88.6 µg/ml xylazine (Bayer, Seoul, Korea). LTB4 (Cayman Chemicals, Ann Arbor, MI) was prepared in PBS containing 20% ethanol to a final concentration of 20 µg/ml, and 50 µl was injected intratracheally. After 6 h, bronchoalveolar lavage (BAL) fluid was collected from the lung space as previously described (17). Briefly, the chest cavity was exposed to allow for expansion, after which the trachea was carefully intubated, and the catheter was secured with ligatures. Eight hundred microliters of prewarmed 0.9% NaCl solution was slowly infused into the lung and withdrawn. The aliquots were then pooled and then kept at 4°C. To obtain differential cell counts, the BAL fluid was cytospun and stained with Diff-Quik (Dade Diagnostics, Aguada, Puerto Rico). Two independent, blinded investigators then counted the cells using a hemocytometer. Approximately 400 cells were counted in each of four randomly selected locations. The percentage of neutrophils was multiplied by the total cell number to obtain the neutrophil count. To evaluate lung histology, the lungs were removed from mice 6 h after LTB4 challenge, cut into sections, and stained with H&E (Sigma-Aldrich) (18).
Data analysis and statistics
Data are expressed as mean percentages of control ± SD. Statistical comparisons between groups were made using Student’s t tests. Values of p < 0.01 were considered significant.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Human promyelocytic HL-60 cells induced with DMSO to differentiate toward neutrophil-like granulocytes (dHL-60) have been shown to be a valid model system for the analysis of human neutrophil migration and chemotaxis, (12, 19, 20). In the present study LTB4 induced migration of dHL-60 cells, but not the parental HL-60 cells, across a monolayer of A549 human type II alveolar epithelial cells (Fig. 1). The effect was concentration dependent, with 2.3-fold more migration occurring in the presence of 100 nM LTB4 than control buffer.
|
|
ROS is critical for the transepithelial migration of dHL-60 cells
Recently, a ROS-dependent pathway was shown to mediate LTB4-induced chemotaxis of Rat-2 fibroblasts (22). To determine whether ROS is similarly involved in the transepithelial migration of dHL-60 cells induced by LTB4, we examined the effect on LTB4-mediated transepithelial migration of ROS inhibition by DPI, an inhibitor of NADPH oxidase-like flavoenzymes, or by NAC, a ROS scavenger. We found that transmigration induced by 100 nM LTB4 was significantly diminished by pretreating dHL-60 cells with DPI and NAC (Fig. 3A). In a similar fashion, pretreatment with DPI or NAC also diminished transmigration induced by PMA. To determine whether LTB4 in fact triggers intracellular ROS generation in dHL-60 cells, we assessed H2O2 levels using DCF. As shown in Fig. 3B, LTB4 elicited a concentration-dependent increase in the level of ROS, and this effect was abolished by pretreating the cells with DPI or NAC (Fig. 3C).
|
We also observed that in dHL-60 cells LTB4 (100 nM) induced phosphorylation of ERK (Fig. 4A), but not p38 or c-Jun amino-terminal kinase (not shown). To further evaluate ERK stimulation by LTB4, ERK’s kinase activity was assessed using an Elk-luciferase trans-reporter system. We found that LTB4 (100 nM) clearly enhanced ERK/Elk-luciferase activity in differentiated dHL-60 cells, but not in wild-type HL-60 cells (Fig. 4B). Moreover, pretreating the cells with 10 or 20 µM PD98059, a specific mitogen-activated protein kinase kinase inhibitor that blocks ERK activation, dose-dependently inhibited the transepithelial migration induced by 100 nM LTB4 (Fig. 4C). Pretreatment with genistein (10 µM), a nonspecific tyrosine kinase inhibitor, had a similar inhibitory effect.
|
We further investigated the mediators contributing to LTB4 signaling by testing the effects of inhibitors of phosphatidylinositol 3-kinase (PI 3-kinase), protein kinase C (PKC), and cytosolic phospholipase A2(cPLA2) on transepithelial migration and ERK activation. We found that LTB4-induced transmigration was completely blocked by pretreatment with 0.1 µM wortmannin, a PI 3-kinase inhibitor, or 0.1 µM GF109203X, a PKC inhibitor (Fig. 5A), and there was a corresponding decrease in the level of ERK activation (Fig. 5B), which suggests that both PI 3-kinase and PKC are situated upstream of ERK in the LTB4 signaling pathway. By contrast, AACOCF3 (10 µM), a specific cPLA2 inhibitor, had no effect on either transmigration or ERK activation (Fig. 5).
|
The functional importance of this ROS-ERK-linked pathway was further confirmed by investigating its presence in human PMNs obtained from peripheral blood of healthy volunteers. As in dHL-60 cells, LTB4 induced significant transepithelial migration of human PMNs, and the effect was significantly diminished by pretreatment with NAC, DPI, or PD98059 (Fig. 6).
|
To investigate the physiological function of ROS-ERK-linked signaling in vivo, BALB/c mice were subjected to intratracheal instillation of LTB4. Analysis of BAL fluid revealed that very few neutrophils were present in the airways following intratracheal instillation of saline (Fig. 7); mostly alveolar macrophages were detected. Following instillation of 1 µg of LTB4 in 50 µl of saline, however, the number of neutrophils in the BAL fluid increased significantly within 6 h (Fig. 7, A and B). This effect was blocked by prior i.p. administration of NAC, DPI, PD98059, or the BLT inhibitor CP105696 (Fig. 7C), suggesting that in vivo a ROS-ERK-linked signaling pathway governs LTB4-mediated neutrophil trafficking into the airway.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
A growing body of evidence suggests that oxygen-derived radicals (e.g., O2- and H2O2) serve as intracellular signaling molecules for a variety of agonists, including LTB4, TNF-
(16, 23, 24), IL-1 (25), and TGF-1 (27), as well as various growth factors (27, 28, 29, 30). In the context of the present study it is notable that a ROS-linked cascade was recently shown to mediate LTB4-induced chemotaxis and proliferation of Rat-2 fibroblasts (22), that oxidant stress generated by LTB4 reportedly induces transendothelial migration of monocytes (31, 32), and that ROS reportedly contribute to integrin-dependent cell adhesion (33, 34). Given the inhibitory effect of DPI on LTB4-induced cell migration and ERK activation, we suggest that NADPH oxidase is the primary source of the ROS generated in response to LTB4. Consistent with that idea, several studies have shown that LTB4 promotes robust, receptor-mediated activation of NADPH oxidase (35, 36, 37), which in eosinophils mediates activation of PKC, phospholipases C and D, and cPLA2 (35, 38).
Neutrophils function in the front line of cellular host defense against microorganisms. This function relies in part on their ability to generate large amounts of O2- and related ROS through activation of NADPH oxidase on the plasma membrane, a phenomenon known as respiratory bursting (14, 36, 39). Thus, ROS generation by NADPH oxidase appears to have a dual function, host defense and intracellular signaling, although it remains unknown how the two functions are respectively regulated. The fact that the level of ROS generated by LTB4 is substantially lower than those seen during respiratory bursts suggests that the regulatory mechanisms are quite different.
We were able to demonstrate that ERK mediates ROS signaling to transepithelial migration of neutrophils both in vitro and in vivo (Figs. 4 and 7). In vivo, the process of transepithelial neutrophil migration occurs through a series of steps orchestrated by the interaction of adhesion molecules on the surface of the neutrophils and proteins secreted by the bronchial epithelial cells. Inhibition of ROS or ERK may interfere with any one or more of these steps.
Recently, we and others reported that PI 3-kinase acts as an upstream mediator of ROS generation, leading to chemotaxis and ERK activation (40, 41). Herein we showed that pretreating dHL-60 cells with wortmannin or GF109203X, inhibitors of PI 3-kinase and PKC, respectively, diminished both LTB4-induced transmigration and ERK phosphorylation, suggesting that PI 3-kinase and PKC act upstream of ERK to regulate LTB4 signaling. Consistent with that idea, PMA, an activator of several PKC isoforms, stimulated transepithelial migration of dHL-60 cells, and the effect was significantly diminished by pretreatment with antioxidants.
ROS generation in response to external stimuli has been related to the activation of transcription factors AP-1 and NF-
B (34), which appear to be involved in the stimulation of the integrins LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18). Although neutrophil adherence and subsequent migration out of postcapillary venules during systemic inflammation are largely dependent on CD18, the existence of CD18-independent neutrophil migration has also been demonstrated (42, 43, 44, 45). For example, when Doerschuk and co-workers (43) compared neutrophil migration in the systemic and pulmonary circulations of rabbits exposed to HCl, Streptococcus pneumonia, E. coli endotoxin, or PMA, they found that migration into the abdominal wall was always CD18 dependent, but migration into the lung was not. Similarly, analysis of neutrophil migration into the inflamed joints of rats with adjuvant arthritis showed that migration could only be completely blocked by combining an anti-CD18 Ab with an Ab recognizing 1 very late Ag 4 (CD49d/CD29). Likewise, monocytes are capable of CD18-independent migration mediated in part by members of the 1 integrin family, very late Ag 4 in particular (44, 45). In addition to integrins, chemokines and proteases, such as elastase, would also seem to be likely downstream targets of ROS-ERK-linked signaling. With further study we anticipate complete clarification of the molecular linkage between the ROS-ERK-linked pathway and its various potential targets. Considering a critical role of LTB4 as a major mediator of PMN transepithelial migration and neutrophil-induced lung injury, specific blockade of the ROS-ERK-linked pathway may have therapeutic value in the treatment of inflammatory diseases such as acute bronchitis, ARDS, COPD, and severe asthma.
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Jae-Hong Kim, Graduate School of Biotechnology, Korea University, 5-1 Anam-dong, Sungbuk-gu, Seoul 136-701, Korea. E-mail address: jhongkim{at}korea.ac.kr
3 Abbreviations used in this paper: LTB4, leukotriene B4; ARDS, adult respiratory distress syndrome; BAL, bronchoalveolar lavage; BLT, LTB4 receptor; COPD, chronic obstructive pulmonary disease; cPLA2, cytosolic phospholipase A2; DCFDA, 2',7'-dichlorofluorescin diacetate; dHL-60, differentiated HL-60 neutrophils; DPI, diphenylene iodonium; ERK, extracellular signal-regulated kinase; NAC, N-acetylcysteine; PMN, polymorphonuclear neutrophil; PI 3-kinase, phosphatidylinositol 3-kinase; PKC, protein kinase C; ROS, reactive oxygen species.
Received for publication November 15, 2002. Accepted for publication April 14, 2003.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
generates reactive oxygen species via a cytosolic phospholipase A2-linked cascade. J. Biol. Chem. 275:32357.B activation. J. Biol. Chem. 277:17871.B in the induction of eosinophilia in allergic airway inflammation. J. Exp. Med. 188:1739.1 and its involvement in induction of egr-1 in mouse osteoblastic cells. J. Cell Biol. 126:1079.2-integrin CD11b/CD18 activation. Eur. J. Immunol. 29:3419.[Medline]
in rat-2 fibroblasts. J. Biol. Chem. 274:24372.-Amyloid activates the O2- forming NADPH oxidase in microglia, monocytes, and neutrophils: a possible inflammatory mechanism of neuronal damage in Alzheimer’s disease. J. Biol. Chem. 274:15493.2 (CD18) and 1 (CD29) integrin mechanisms in migration of human polymorphonuclear leucocytes and monocytes through lung fibroblast barriers: shared and distinct mechanisms. Immunology 92:527.[Medline]
This article has been cited by other articles:
|
|
 |
|
  D. Rittirsch, M. A. Flierl, D. E. Day, B. A. Nadeau, S. R. McGuire, L. M. Hoesel, K. Ipaktchi, F. S. Zetoune, J. V. Sarma, L. Leng, et al. Acute Lung Injury Induced by Lipopolysaccharide Is Independent of Complement Activation J. Immunol., June 1, 2008; 180(11): 7664 - 7672. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Kuribayashi, K. Nakamura, M. Tanaka, T. Sato, J. Kato, K. Sasaki, R. Takimoto, K. Kogawa, T. Terui, T. Takayama, et al. Essential role of protein kinase C {zeta} in transducing a motility signal induced by superoxide and a chemotactic peptide, fMLP J. Cell Biol., March 26, 2007; 176(7): 1049 - 1060. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. A. Lundeen, B. Sun, L. Karlsson, and A. M. Fourie Leukotriene B4 Receptors BLT1 and BLT2: Expression and Function in Human and Murine Mast Cells. J. Immunol., September 1, 2006; 177(5): 3439 - 3447. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. Sela, N. Mauermann, R. Hershkoviz, H. Zinger, M. Dayan, L. Cahalon, J. P. Liu, E. Mozes, and O. Lider The Inhibition of Autoreactive T Cell Functions by a Peptide Based on the CDR1 of an Anti-DNA Autoantibody Is via TGF-{beta}-Mediated Suppression of LFA-1 and CD44 Expression and Function J. Immunol., December 1, 2005; 175(11): 7255 - 7263. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Edderkaoui, P. Hong, E. C. Vaquero, J. K. Lee, L. Fischer, H. Friess, M. W. Buchler, M. M. Lerch, S. J. Pandol, and A. S. Gukovskaya Extracellular matrix stimulates reactive oxygen species production and increases pancreatic cancer cell survival through 5-lipoxygenase and NADPH oxidase Am J Physiol Gastrointest Liver Physiol, December 1, 2005; 289(6): G1137 - G1147. [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]
|
|
|
|
 |
|
 C. H. C. Serezani, D. M. Aronoff, S. Jancar, P. Mancuso, and M. Peters-Golden Leukotrienes enhance the bactericidal activity of alveolar macrophages against Klebsiella pneumoniae through the activation of NADPH oxidase Blood, August 1, 2005; 106(3): 1067 - 1075. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Iizuka, T. Yokomizo, K. Terawaki, M. Komine, K. Tamaki, and T. Shimizu Characterization of a Mouse Second Leukotriene B4 Receptor, mBLT2: BLT2-DEPENDENT ERK ACTIVATION AND CELL MIGRATION OF PRIMARY MOUSE KERATINOCYTES J. Biol. Chem., July 1, 2005; 280(26): 24816 - 24823. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. Sela, R. Hershkoviz, L. Cahalon, O. Lider, and E. Mozes Down-Regulation of Stromal Cell-Derived Factor-1{alpha}-Induced T Cell Chemotaxis by a Peptide Based on the Complementarity-Determining Region 1 of an Anti-DNA Autoantibody via Up-Regulation of TGF-{beta} Secretion J. Immunol., January 1, 2005; 174(1): 302 - 309. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-H. Woo, J.-H. Lim, and J.-H. Kim Lipopolysaccharide Induces Matrix Metalloproteinase-9 Expression via a Mitochondrial Reactive Oxygen Species-p38 Kinase-Activator Protein-1 Pathway in Raw 264.7 Cells J. Immunol., December 1, 2004; 173(11): 6973 - 6980. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Huang, A. Zhao, F. Wong, J. M. Ayala, M. Struthers, F. Ujjainwalla, S. D. Wright, M. S. Springer, J. Evans, and J. Cui Leukotriene B4 Strongly Increases Monocyte Chemoattractant Protein-1 in Human Monocytes Arterioscler. Thromb. Vasc. Biol., October 1, 2004; 24(10): 1783 - 1788. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
