| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Published online before print October 5, 2004
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Cardiovascular Research Unit, University of Sheffield, United Kingdom
1 Correspondence: University of Sheffield, Clinical Sciences Centre, Northern General Hospital, Herries Road, Sheffield S5 7AU, UK. E-mail: k.norman{at}sheffield.ac.uk
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Key Words: inflammation • neutrophils • in vivo animal models • intravital microscopy • venules • sialyl LewisX • flow-based adhesion assay
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
(TNF-), lipopolysaccharide], facilitates low-velocity leukocyte rolling [7
], resulting in long transit times, which are essential for efficient leukocyte adhesion [8
]. P-selectin can be up-regulated by cytokines but is also found preformed and stored in Weibel-Palade bodies of endothelial cells and -granules of platelets. P-selectin appears on the surface of stimulated cells within minutes [2
, 9
]. The selectins interact with glycoprotein ligands, post-translationally modified to express fucosylated, sialylated glycans [e.g., sialyl LewisX (sLeX)]. Inhibiting the selectins with molecules that mimic natural selectin ligands has the potential to treat inflammatory diseases. TBC-1269, a low molecular weight, nonoligosaccharide selectin inhibitor, was discovered using sLex as a lead and has been shown to inhibit P-, E-, and L-selectin-dependent adhesion in vitro [10 , 11 ]. Preclinical studies have demonstrated anti-inflammatory actions of TBC-1269, but a recent phase II clinical trial for asthma failed to show any benefit [12 ]. Results of a trial for psoriasis have yet to be reported. Although leukocyte rolling is the proposed mechanistic target for TBC-1269 [13 14 15 ], effects on rolling in vivo have not been demonstrated. The aim of the present study was to evaluate the effects of TBC-1269 in well-characterized murine models of inflammation and to determine whether the anti-inflammatory activity of this molecule can be related directly to effects on leukocyte rolling.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
were purchased from R&D Systems (Abingdon, UK). Anti-human IgG1 Fc fragment antibody was purchased from Calbiochem (Nottingham, UK). Rat anti-mouse P-selectin antibody RB40.34 (rat IgG1) was purchased from PharMingen (Oxford, UK). Rat anti-mouse E-selectin 10E6 (rat IgG2b) and control antibodies (10A10, nonblocking anti-P-selectin IgG1, and 2-4A1, isotype control for 10E6) were kind gifts from Dr. Barry A. Wolitzky (Hoffman-La Roche Inc., Nutley, NJ).
TBC-1269
TBC-1269 was used at concentrations up to 1000 µg/ml in vitro. P-selectin-coated microslides and 32DCl3 cell suspensions were treated with TBC-1269 at the indicated concentration, ensuring that TBC-1269 concentration remained constant throughout experiments. Initial in vivo experiments were performed using doses of 25 mg/kg TBC-1269. Selection of this dose was based on previously published studies in which anti-inflammatory effects were seen [13
, 15
]. In some experiments, we also tested 100 mg/kg. TBC-1269 was administered as a subcutaneous (s.c.) pretreatment when studying thioglycollate-induced peritonitis. s.c. dosing allowed treatment of a large number of mice with close control of injection times, which we find to be essential for reproducible responses. In initial, intravital microscopy experiments, rolling was allowed to develop before administration of TBC-1269, which was given intravenously (i.v.). Later, intravital microscopy experiments studied the consequence of i.v. pretreatment with TBC-1269 on leukocyte rolling.
32DCl3 cells
The mouse neutrophilic progenitor cell line 32DCl3 was cultured in Iscove’s modified Dulbecco’s medium (Gibco-BRL, Grand Island, NY) containing 1 ng/ml interleukin-3 (Peprotech, London, UK), 100 U/ml penicillin and streptomycin, and 10% fetal calf serum (Advanced Protein Products, Brierly Hill, UK). Before use in the flow-based adhesion assay, cells were resuspended at a concentration of 1 x 106 cells/ml in phosphate-buffered saline (PBS; containing 1 mM Ca2+ and 0.5 mM Mg2+; Gibco-BRL) and 0.15% bovine serum albumin (BSA; fraction IV, Sigma Chemical Co., St. Louis, MO). TBC-1269, at the appropriate concentration, was added to the cells immediately before use.
Flow-based adhesion assay
Microslides (glass capillary tubes, 5 cm long, with a rectangular cross-section of 3x0.3 mm) were coated with 3-aminopropyltriethoxysilane (APES) as described [16
]. Anti-human IgG1 antibody (20 µg/ml) was introduced into the microslides and allowed to bind to the APES at 4°C overnight. The following morning, the microslides were washed and filled with 1% BSA in PBS and incubated at 37°C for a further 2 h to block any free, protein-binding sites. The BSA was replaced with fresh 1% BSA, 1 h into this incubation. Murine P-selectin/Fc chimera (5 µg/ml) in PBS was then aspirated into the microslides and incubated at 37°C for 60 min to allow binding to the anti-IgG1 antibody. TBC-1269 was introduced into the P-selectin-coated microslides and incubated at 37°C for 30 min, before being held at room temperature until use.
The assay system was as described previously [17 ]. Microslides were connected at one end to a syringe pump, which drew fluid through the microslide at a flow rate equivalent to a wall shear stress of 0.1 Pa (1 dyn/cm2). The other end was connected to an electronic valve, which allowed switching between perfusion of cells or PBS/BSA. The microslides were mounted on a phase-contrast video-microscope, enclosed at 37°C. 32DCl3 cells were perfused over the P-selectin for 4 min, followed by 2 min of wash buffer. Adhesive interactions could be visualized directly and were also video-recorded. Video recordings were analyzed off-line.
Animals
Male, wild-type C57BL/6 (Harlan), P-selectin–/– (in-house, colony-derived from C57BL/6J-Selptm1Bay, The Jackson Laboratory, Bar Harbor, ME), and E-selectin–/– mice (in-house, colony-derived from breeding pairs supplied by Dr. B. A. Wolitzky) [18
], weighing between 25 and 35 g, were used in these experiments. All procedures were approved by the University of Sheffield Ethics Committee (UK) and by the Home Office Animals (Scientific Procedures) Act of 1986.
Neutrophil accumulation in thioglycollate-induced peritonitis
TBC-1269 (25 mg/kg), vehicle, or antibodies were injected (s.c.) into wild-type or selectin–/– mice, and 1 ml intrperitoneal (i.p.) injections of 3% thioglycollate broth or 0.9% saline were administered 15 min later. Four hours after thioglycollate, mice were killed by cervical dislocation. Heparinized saline (5 ml, 10 U/ml) was injected into the peritoneum, the abdomen gently massaged, and lavage fluid recovered via a small incision into the abdominal cavity. Total leukocyte counts were performed using a modified Neubauer haemocytometer, and differential counts were performed on Giemsa-stained cytospin slides. Neutrophil accumulation data are presented, and the response given by saline was subtracted.
Intravital microscopy
Mice were anaesthetized with an i.p. injection (12.5 µl/g) of anesthetic mixture consisting of 10 mg/ml ketamine hydrochloride (Ketaset; Willows Francis Veterinary, Crawley, UK), 1 mg/ml xylazine hydrochloride (Bayer, Suffolk), and 0.02 mg/ml atropine sulfate (Phoenix Pharmaceuticals Ltd., UK). Mice were given additional anesthesia (pentobarbital 5 mg/ml, i.v.) as required (Sagatal, Rhone Merieux Ltd., Australia). Some mice received an intrascrotal injection of murine TNF- (500 ng in 200 µl saline) 2 h before intravital microscopy. Before exteriorization of the cremaster for intravital microscopy, the following cannulations were performed: the trachea to facilitate breathing; the jugular vein to allow i.v. injection of TBC-1269, antibodies, and additional anesthesia; and the carotid artery to permit blood sampling and for injection of microspheres. Body temperature was maintained at 37°C using a thermocontrolled heat pad (PDtronics, Sheffield, UK). The cremaster muscle was prepared for microscopic observation as described [19
, 20
]. During this preparation and subsequent intravital microscopy, the cremaster muscle was superfused with thermocontrolled (36°C) bicarbonate buffer solution (131.9 mM NaCl, 18 mM NaHCO3, 4.7 mM KCl, 2.0 mM CaCl2, and 2 mM MgSO4) through which a gas mixture of 5% CO2 in N2 was bubbled.
Microscopic observations were made using a light microscope (Nikon Eclipse E600-FN, Nikon UK Ltd., Surrey) equipped with a water immersion objective (40x/0.80 W). Venules between 20 and 50 µm diameter were selected for observation, and images of transilluminated rolling leukocytes were recorded using a 3-chip 1/3'' charged-coupled device camera (Dage MTI DC-330, DAGE MTI, Inc., Michigan City, IN) on an s-VHS video recorder (Panasonic AG4700, Quadrant Visual Solutions, Derby). The video recorder was linked to a video timer, accurate to 1/100th of a second, allowing addition of a time/date function to the recorded images (VT330, FORA, Natick, MA). Venules were typically recorded in 1-min segments, except where antibodies and treatments were applied, in which case recordings began 1 min before treatment and continued until 5 min after injection. After recording leukocyte rolling in a given vessel, the microscope was adjusted to observe passage of fluorescent microspheres (1.0 µm, Molecular Probes, Junction City, OR) through the same vessel by dual flash stroboscopic (Strobex 236, Chadwick Helmuth, Mountain View, CA) epifluorescence illumination. Activation of the Strobex lamp (used for epifluorescent illumination of microspheres) was controlled by the video camera. Two brief, high-intensity flashes were produced for each video frame, giving two high-resolution images of fast, free-flowing microspheres. Images of fluorescent microspheres were also recorded onto sVHS videocassettes via a silicon-intensified target camera (Series 66, Hammamatsu Photonics, Enfield). Blood samples (10 µl) were drawn from the carotid artery at 10-min intervals and 2 min before and after treatments and were analyzed for total leukocyte concentration.
Off-line analysis
After collection of data, sequences of interest were digitized (Miromotion DC30, Pinnacle Systems, Mountain View, CA) and stored on a Macintosh G3/400 computer prior to analysis using the public domain National Institutes of Health Image program (available on the internet at http://rsb.info.nih.gov/nih-image).
For flow-based adhesion assay experiments, the percentage of adherent neutrophils, which were rolling or stationary, was determined. Velocities of cells rolling during the last minute of inflow were measured by a custom, written macro, which records x–y positions of moving objects over successive video frames as described [21 ]. During the last minute of the wash-phase, the number of cells was counted in a series of microscope fields along the centerline of the microslide and was expressed as cells bound/mm2/106 perfused.
For analysis of in vivo experiments, diameters and lengths of observed vessel segments were measured using the built-in line tool. Velocities of microspheres and rolling leukocytes were measured as above. As the flash rate of the Strobex was known (two flashes, 10 ms apart on each video frame), we were able to accurately determine microsphere velocity by measuring the distance between images. We measured the velocities of 10 microspheres appearing to occupy the centerline of blood flow and took the mean velocity of the three fastest as an estimate of centerline velocity.
To compare leukocyte rolling before and after different treatments, rolling flux was determined by counting the number of cells rolling past a plane perpendicular to the vessel axis. Vessel diameter together with blood flow velocity and whole blood leukocyte concentration were used to estimate total leukocyte flux (assuming cylindrical vessel geometry and uniform distribution of leukocytes in the microcirculation). Leukocyte rolling data are presented as rolling flux percent, which is defined as the rolling leukocyte flux expressed as a percentage of total leukocyte flux. Where rolling was observed before and after treatment, data are expressed as percentage of control rolling.
In each vessel studied, rolling flux percent and rolling velocities were determined immediately before and after i.v. injection of TBC-1269 or at fixed times after pretreatment with TBC-1269 or drug vehicle. Rolling flux percent and rolling velocities were also determined immediately before and after i.v. injection of P-selectin (RB40.34)- and E-selectin (10E6)-blocking antibodies.
Statistical analysis
The rolling velocities and number of adherent 32DCl3 cells in vitro were compared using one-way ANOVA followed by the Newman-Keuls multiple comparison test. Leukocyte rolling fluxes and velocities in vivo were compared using Student’s unpaired t-test, and differences between data in peritonitis experiments compared using the Mann-Whitney test or the Kruskal-Wallis test followed by a Dunn’s post-test for nonparametric data. All statistical tests were performed using GraphPad Prism (San Diego, CA, www.graphpad.com) software according to the manufacturer’s instructions.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
TBC-1269 inhibited 32DCl3 adhesion to P-selectin in a concentration-dependent manner (Fig. 1a ). The highest concentration of TBC-1269 reduced adhesion by 86% compared with untreated control. A trend for increased rolling velocity at high concentrations of TBC-1269 was also observed (Fig. 1b) , although results did not reach statistical significance, possibly as a result of the low number of cells still rolling in the 1000 µg/ml group.
|
|
2x106) neutrophils to the peritoneal cavities of P-selectin–/– than wild-type mice (Fig. 2b)
, which is consistent with published studies [22
]. TBC-1269 inhibited neutrophil recruitment in P-selectin–/– mice by 78% compared with 97% inhibition given by anti-E-selectin antibody 10E6. The control antibody 2-4A1 had no significant effect on neutrophil recruitment in P-selectin–/– mice. E-selectin–/– mice developed a slightly more intense response to thioglycollate than P-selectin–/– mice (Fig. 2c)
. This was reduced 75% by the anti-P-selectin antibody RB40.34, whereas the control antibody had no significant effect (Fig. 2c)
. It is interesting that TBC-1269 did not inhibit neutrophil accumulation in E-selectin–/– mice (Fig. 2c)
, suggesting that E-selectin expression may be required for TBC-1269 to exert its anti-inflammatory effect.
Effect of TBC-1269 on established leukocyte rolling
We also studied effects of TBC-1269 on leukocyte rolling in vivo. Surgery to the cremaster stimulated P-selectin-dependent rolling in postcapillary venules as described [20
]. Baseline rolling was measured in each observed venule 30 min after surgery and was set to 100% (Fig. 3a
). Subsequent injection of TBC-1269 did not alter the number of rolling cells. To confirm that rolling in our model was P-selectin-dependent, mice were treated with an anti-P-selectin antibody, RB40.34 (10 µg i.v.), which reduced rolling substantially. As weak selectin antagonists increase leukocyte-rolling velocities [23
], we also measured this parameter before and after treatment with TBC-1269, which did not change leukocyte-rolling velocities (Fig. 3b)
in surgically stimulated mice (a shift to the right would indicate increased velocity of the rolling population).
|
(500 ng intrascrotal, 2 h) induced E- and L-selectin-dependent leukocyte rolling in postcapillary venules as described [20
, 24
]. Leukocyte rolling under these conditions can be inhibited partially by the anti-L-selectin antibody MEL-14 [20
] and almost abolished by the E-selectin-blocking antibody 10E6 [25
]. In addition, TNF--stimulated L-selectin-deficient mice have reduced rolling and are more sensitive to P-selectin-blocking antibody compared with wild-types [7
]. Baseline rolling was measured in each observed venule 150 min after TNF- and set to 100%. Subsequent addition of TBC-1269 did not affect number of rolling cells or alter leukocyte rolling velocity (Fig. 3c
and 3d)
in P-selectin–/– mice, prestimulated with TNF-, contrasting with the effects of 10E6, which strongly inhibited leukocyte rolling in observed venules (Fig. 3c)
.
TBC-1269 did not affect established leukocyte rolling in surgically stimulated wild-type or TNF--stimulated P-selectin–/– mice, suggesting that it does not competitively inhibit P-, L-, or E-selectin in vivo.
Effect of TBC-1269 pretreatment on leukocyte rolling
As reported above and by others [13
, 14
], anti-inflammatory effects of TBC-1269 have been seen when given as a pretreatment. We therefore studied whether pretreatment with TBC-1269 could affect leukocyte rolling. TBC-1269 (25 mg/kg i.v.) was given 15 min before surgical stimulation of tissue, and rolling was observed and recorded 30 min after surgery. TBC-1269 pretreatment had no significant effect on the number of rolling leukocytes (Fig. 4a
). P-selectin dependence was confirmed using RB40.34 (10 µg i.v.), which abolished rolling in vehicle- and TBC-1269-pretreated groups. TBC-1269 pretreatment had no significant effect on rolling velocity in these experiments (Fig. 4b)
.
|
-stimulated leukocyte rolling in P-selectin–/– mice. TNF- was injected intrascrotally 15 min after i.v. pretreatment with TBC-1269, and leukocyte rolling in cremasteric venules was observed 150 min later. TBC-1269 pretreatment had no significant effect on the number or velocity of rolling leukocytes in TNF--stimulated P-selectin–/– mice (Fig. 4c
and 4d)
. E-selectin dependency was confirmed using 10E6 (10 µg i.v.), which reduced numbers of rolling cells in vehicle- and TBC-1269-pretreated groups.
Hemodynamic factors
As hemodynamic factors, such as vessel diameter and blood-flow velocity, can influence leukocyte rolling directly, these factors were measured in each intravital microscopy experiment. In most experiments, any effect of hemodynamic variation on leukocyte rolling was avoided by making comparisons in the same vessels before and after treatment. In these experiments, TBC-1269 did not alter blood flow velocity or systemic leukocyte counts (not shown). In experiments where comparison of the same vessels before and after treatment was not possible (i.e., pretreatment studies), we attempted to select vessels with similar diameter and blood-flow velocities. Blood flow in TBC-1269-pretreated P-selectin knockout mice was lower than vehicle-treated mice (Table 1
) but was within a generally normal range for this type of experiment. Systemic white blood cell concentrations did not vary between vehicle- and TBC-1269-pretreated animals (Table 1)
.
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
We find that TBC-1269 inhibits rolling of a murine cell line (32DCl3) on murine P-selectin in vitro and has pronounced, anti-inflammatory activity in mice when given prior to induction of thioglycollate-induced peritonitis. These findings extend work of others who have demonstrated effects of TBC-1269 against human neutrophil rolling/adhesion in vitro [11 ] and anti-inflammatory effects in various species, including rats, sheep, and dogs [13 14 15 , 31 ]. In contrast, we were surprised to find that TBC-1269 failed to influence established leukocyte rolling in vivo at doses that match or exceed those with pronounced, anti-inflammatory activity. We have tested a number of other selectin antagonists [recombinant P-selectin glycoprotein ligand (PSGL)-Ig, glycosulfopeptides, sLex mimetics], which inhibit established leukocyte rolling at similar or lower doses to TBC-1269 [23 , 29 , 30 , 32 ]. Bioavailability should not have limited the activity of TBC-1269 in studies of leukocyte rolling, as it was applied i.v., and effects were determined immediately after injection. These results suggest that TBC-1269 limits inflammation by a mechanism other than direct competition with cell-bound selectin ligands. Considering data from our own peritonitis experiments and previously published investigations [13 , 14 ], we hypothesized that pretreatment with TBC-1269 may be required for an anti-inflammatory effect to be seen. Pretreatment with TBC-1269 also failed to influence leukocyte rolling, however.
As TBC-1269 was rationally designed to mimic the natural selectin ligand sLex, we considered the possibility that it might act via the selectins, although it failed to greatly alter established leukocyte rolling. P-selectin and E-selectin knockout mice retain the ability to recruit neutrophils in response to irritant-induced peritoneal inflammation [18
, 22
], offering the potential to study the effects of TBC-1269 on this response in the absence of one or other of its potential ligands. TBC-1269 was shown to inhibit neutrophil recruitment in P-selectin–/– but not E-selectin–/– mice, indicating that TBC-1269 may require E-selectin but not P-selectin for anti-inflammatory effect. Ours is not the first demonstration that an agent directed against E-selectin can have anti-inflammatory activity without influencing leukocyte rolling. The E-selectin antibody 10E9.6 has no effect on leukocyte rolling in TNF--stimulated mouse cremaster muscle but inhibits thioglycollate-induced peritonitis more effectively than antibody 9A9 [28
], which does block E-selectin-dependent rolling. Taken together, these results suggest that E-selectin has an important function beyond leukocyte rolling and that agents directed against this molecule can have a marked, anti-inflammatory effect without altering rolling. Although the mechanism of this effect is not clear, signaling functions of E-selectin have been proposed and may offer some explanation.
Although the most widely accepted function of E-selectin is in the maintenance of slow leukocyte rolling, which maximizes contact of neutrophils with chemokine-expressing endothelial cells and thus, the transition from rolling to firm adhesion, a number of investigations point to a second potential function. Clustering of L-selectin or PSGL-1 by cross-linking antibodies is well known to activate leukocytes inducing multiple activation markers, including calcium release, mitogen-activated protein kinase (MAPK) signaling pathway activation, ß2-integrin activation, and adhesion [33 34 35 36 ]. Although the physiological relevance of antibody-induced clustering is not clear, recent studies have demonstrated that recognition of L-selectin or PSGL-1 by E-selectin induces leukocyte activation by similar mechanisms. Simon and co-workers [37] have demonstrated that neutrophils rolling on cell lines expressing E-selectin and intercellular adhesion molecule-1 (ICAM-1) undergo ß2-integrin activation and arrest via a mechanism that involves p38 and p42/44 MAPK signaling and are independent of G-proteins traditionally associated with chemoattractant receptors. This activation mechanism was associated with E-selectin-dependent concentration of L-selectin and PSGL-1 into membrane caps that form at the trailing edge of rolling neutrophils [38 ]. It is interesting that the same group also demonstrated that TBC-1269 not only inhibited coclustering of L-selectin and PSGL-1 induced by E-selectin but also, arrest of human neutrophils rolling on L-cells transfected with ICAM-1 and E-selectin. Considered alongside our own findings that TBC-1269 inhibits thioglycollate-induced peritonitis but not leukocyte rolling in vivo, this suggests that inhibition of E-selectin-dependent neutrophil activation rather than rolling may explain the anti-inflammatory properties of TBC-1269.
As well as suggesting an alternative mechanism of action for designed selectin inhibitors, our studies indicate that findings from in vitro assays of selectin inhibitor function do not necessarily predict effects on leukocyte rolling in vivo. TBC-1269 was selected and characterized on the basis of its ability to bind to selectins and inhibit binding to synthetic selectin ligands in vitro. It inhibits rolling of human neutrophils and eosinophils [11 ] as well as murine 32DCl3 cells in vitro but has no effect on in vivo leukocyte rolling, which is known to be selectin-dependent. These differences might be attributed to numerous factors, including effects of the whole organism on bioavailability, differences between murine and human selectins, different densities of selectin ligands on different leukocytes or leukocytes from different species, and influences of physiological conditions (e.g., blood flow) on selectin function. We consider bioavailability to be a minor consideration for our studies, as leukocyte rolling is observed prior to, during, and immediately after i.v. injection of compound. We have tested other agents that are cleared rapidly (sLex mimetics [32 ], glycosulfopeptides [29 ]), and routinely detect at least transient effects on rolling, as injected inhibitors make their first pass through the cremaster circulation. Species differences are also unlikely to be a factor, as we have demonstrated that TBC-1269 is effective against murine selectins in vitro. We [39 , 40 ] and others [41 ] have also performed a number of studies investigating interaction of human selectin ligands with murine selectins, and find them to be functionally similar.
TBC-1269 is more effective against rolling of human neutrophils than eosinophils, which is suggested to be a result of a higher density of PSGL-1 on eosinophils [11 ]. We showed previously that murine neutrophils express considerably more PSGL-1 than human neutrophils [40 ], raising the possibility that mouse neutrophils are resistant to the effects of TBC-1269 because of greater ligand density. Although this may partially explain the discrepancy between effects of TBC-1269 in vitro and in vivo, it does not account for the complete absence of activity of TBC-1269 against leukocyte rolling, even at doses fourfold higher than the anti-inflammatory dose.
In conclusion, we have demonstrated that as for other species, TBC-1269 has pronounced, anti-inflammatory activity in mice and inhibits murine leukocyte rolling in vitro. TBC-1269 does not inhibit selectin-dependent leukocyte rolling in vivo at the doses tested, however, suggesting an alternate mechanism of action for its anti-inflammatory effect. Peritonitis experiments with selectin-deficient mice suggest E-selectin as a potential molecular target for the anti-inflammatory effects of TBC-1269, although further studies are required to determine the mechanism of this effect.
|
ACKNOWLEDGEMENTS |
|---|
Received November 19, 2003; revised August 13, 2004; accepted September 14, 2004.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
-D- mannopyranosyloxy)phenyl]hexane (TBC-1269) J. Med. Chem. 41,1099-1111[CrossRef][Medline]
This article has been cited by other articles:
|
|
 |
|
  B. P. O'Sullivan and A. D. Michelson The Inflammatory Role of Platelets in Cystic Fibrosis Am. J. Respir. Crit. Care Med., March 1, 2006; 173(5): 483 - 490. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
