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Pulmonary and Critical Care Medicine Division, Department of Internal Medicine, Ann Arbor Veterans Affairs Medical Center and University of Michigan Medical Center, Ann Arbor, MI 48109
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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We reasoned that if uPAR plays a physiologically important role in neutrophil recruitment in response to infectious agents, it would likely be through the modulation of ß2 integrin function. Pseudomonas aeruginosa is a common pulmonary pathogen and is a leading cause of nococomial pneumonia in the United States and Europe (15). Neutrophil recruitment to the lung in response to P. aeruginosa pneumonia is ß2 integrin dependent, as Ab blockade of ß2 integrin function has been shown to substantially reduce neutrophil recruitment in response to this pathogen (16). We show that mice deficient in uPAR, while having comparable numbers of bronchoalveolar lavage cells and bronchoalveolar neutrophils as WT mice when uninfected, have profoundly diminished neutrophil recruitment in response to P. aeruginosa lung infection compared with WT mice. WT mice have markedly diminished recruitment in response to P. aeruginosa lung infection when treatment with anti-CD11b mAb is given i.v. before inoculation with the pathogen, while recruitment of uPAR-/- neutrophils is unaffected by mAb pretreatment. From these studies we conclude that uPAR expression plays a physiologically relevant role in the recruitment of neutrophils in response to P. aeruginosa, a pathogen that recruits neutrophils to the pulmonary parenchyma by a ß2 integrin-dependent mechanism.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Mice were housed in specific pathogen-free isolation rooms in the University of Michigan Department of Laboratory Animal Medicine, which is fully accredited by the American Association for Accreditation of Laboratory Animal Care. This study was approved by the University of Michigan committee on use and care of animals. Mice were periodically checked for murine hepatitis virus and were found to be negative; they were fed standard animal chow (Rodent Lab Chow 5008, Ralston Purina, St. Louis, MO) and chlorinated tap water ad libitum. Mice were used at 8–12 wk of age.
Transgenic uPAR-deficient mice (uPAR-/-), uPA-deficient mice (uPA-/-), and background-matched control mice (WT) were gifts from Dr. Peter Carmeliet (Center for Molecular and Vascular Biology, Leuven, Belgium). These mice were developed as previously described (17, 18). Briefly, the uPAR or uPA gene was knocked out by homologous recombination with a uPAR/neomycin or uPA/neomycin construct in ES cells derived from strain 129 mice. The ES cells were then injected into C57/B6 blastocysts, and the resulting chimeric males were bred with C57/B6 females to produce transgenic mice heterozygous for the uPAR or the uPA gene, respectively. Breeding of these progeny resulted in mice that were homozygous for the knockout or the normal gene or were heterozygous. The homozygous mice were used to establish the uPAR-/-, the uPA-/-, and the WT lines used to generate our colonies. The genotypes of the uPA-/-, uPAR-/-, and WT mice were confirmed by PCR or RT-PCR analysis as described previously (18, 19). Mice of this background (C57B6/129) are immunocompetent, and have preservation of complement-dependent acute lung injury (20).
Antibodies
Anti-murine CD11b (M1/70.15) mAbs and rat IgG (control) were obtained from PharMingen (San Diego, CA).
Harvesting of elicited peritoneal macrophages (M
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uPAR-/- and WT
mice were injected i.p. with 1 ml of 5% thioglycolate. Seven days
later peritoneal macrophages were harvested by serial i.p. lavage with
5 mM EDTA in normal saline. The M were washed and resuspended in
RPMI 1640 (Life Technologies, Grand Island, NY) containing 5% FBS
(Life Technologies). M were 51Cr (Amersham,
Arlington Heights, IL) labeled using standard techniques.
Preparation of murine endothelial cells
Murine endothelial cells (IP-1B, American Type Culture Collection, Manassas, VA) were cultured according to the supplier’s instructions and grown to confluent monolayers in 24-well plates.
M adhesion assay
51Cr-labeled M (1 x
106/ml) were dispensed upon and permitted to
adhere to confluent endothelial monolayers for 30 min at 37°C in 5%
CO2 and humidified air. Following adherence, the
endothelial cells were vigorously washed with warm RPMI 1640 to remove
nonadherent M. The contents of each well were lysed, and the counts
per minute, as a reflection of number of adhered M, was determined
on a scintillation counter.
P. aeruginosa intratracheal (IT) inoculation
P. aeruginosa strain UI-18 (Parke-Davis, Ann Arbor, MI) was the pathogen used in experiments. P. aeruginosa was grown in trypsin soy broth (Difco, Detroit, MI) for 18 h at 37°C. The concentration of bacteria was determined by measurement of absorbance at 600 nm compared with a standard absorbance curve based on known CFU. Bacteria were pelleted by centrifugation at 3000 rpm for 15 min, washed twice in normal saline, and resuspended at the indicated concentration. Mice were lightly anesthetized with pentobarbital (64 mg/kg i.p.; Butler, Columbus, OH) and restrained on a small board. Each mouse received an IT inoculum of 1 x 107 P. aeruginosa in 30 µl of PBS as previously described (21). Aliquots of the inoculum were serially diluted and plated out to confirm the number of CFU of P. aeruginosa delivered. Control mice that received an IT inoculation with PBS were examined histologically at various times after inoculation and showed no evidence of pulmonary inflammation.
Ab treatment
In some experiments mice were injected i.v. with anti-murine CD11b mAb (rat) or control rat IgG (2 mg/kg) 15 min before IT inoculation with P. aeruginosa.
Determination of neutrophil recruitment
At the indicated times following IT inoculation, the mice were killed with an overdose of pentobarbital (250 mg/kg i.p.). After opening the thoracic cavity and the trachea, a polyethylene catheter was inserted into the trachea, and the lungs were lavaged with warmed calcium- and magnesium-free PBS containing 0.6 mM EDTA in 0.5-ml aliquots (22). The bronchoalveolar lavage (BAL) was centrifuged at 500 x g for 10 min at 4°C, an aliquot of the fluid was removed for determination of CFU, the cell pellets were washed twice in PBS, and the cells were enumerated using a hemocytometer. To determine cell differentials, aliquots were cytocentrifuged onto glass slides and stained with Wright-Giemsa (Biochemical Sciences, Swedesboro, NJ). Blinded differential counts were performed on at least 200 cells/slide.
CFU assay
The CFU assay was performed as previously described (21). Briefly, serial 10-fold dilutions of BAL fluid were plated on soy-blood agar base (Difco) supplemented with 5% defibrinated sheep blood (Colorado Serum Co., Denver, CO) in duplicate and incubated at 37°C. P. aeruginosa colonies were counted 18 h later, and the number of CFU was calculated on a per lung basis.
Preparation of histologic specimens
For histologic sections, the trachea was cannulated, and the lungs were inflated in situ with 10% formalin in PBS. Next, the entire thoracic contents were dissected and fixed by immersion in 10% formalin in PBS for 18–24 h. The fixed tissues were transferred to 70% ethanol. Parasagittal sections through the fixed lungs were cut, embedded in paraffin, and sectioned at 5-µm thickness. The slides, each representative of both lungs from a single mouse, were stained serially with hematoxylin and eosin or were Gram stained for identification of P. aeruginosa. Each slide was scanned at low power, and representative sections were identified.
Statistical analysis
Comparisons between group means were performed using unpaired
Student’s t test. Where appropriate, data were log
transformed to ensure equivalent variances between groups. Statistical
calculations were made using StatView 4.5 software (Abacus Concepts,
Berkeley, CA). The number of mice in each experimental group is
indicated (n). Data are expressed as the mean ± SEM.
Statistical difference was accepted at p 
0.05.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Peritoneal macrophages were harvested following thioglycolate
elicitation from the peritoneal cavities of WT and
uPAR-/- mice. The
macrophages were labeled with 51Cr and then
layered over confluent wild-type murine pulmonary capillary endothelial
cell monolayers and allowed to adhere. Nonadhered macrophages were
rinsed from the endothelial cell monolayer, and the relative number of
adherent macrophages was determined by lysis and quantitation of counts
per minute of 51Cr. As shown in Fig. 1
, the
uPAR-/- macrophages
adhered significantly more poorly than did the WT macrophages to the
endothelial cells (p = 0.0088). Because M
adherence to endothelial cells is largely CR3 dependent, this suggests
that the lack of uPAR expression inhibits CR3-mediated adherence.
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Encouraged by the above findings, we moved to an in vivo model
where pulmonary neutrophil recruitment was assessed in response to
P. aeruginosa inoculation. P. aeruginosa was
chosen as a pathogen because neutrophil recruitment has been previously
demonstrated to be dependent on ß2 integrin
function when this pathogen is inoculated into the lung
(16). WT and
uPAR-/- mice were
inoculated with diluent (PBS), and the number of cells obtained by BAL
was determined at 4 h. The total number of cells obtained by BAL
was comparable in response to IT inoculation with PBS comparing WT and
uPAR-/- mice. In both
instances, the number of neutrophils was 
5% of the total number of
BAL cells. Thus, in the absence of inoculation of P.
aeruginosa, both WT animals and
uPAR-/- mice had
comparable numbers of total cells and neutrophils in the pulmonary
alveolar space.
WT and uPAR-/- mice were
IT inoculated with 107 P. aeruginosa
organisms suspended in PBS. Animals were sacrificed and subjected to
BAL at 4 and 8 h post-IT inoculation. As demonstrated in Fig. 2A, at 4 h post-IT
inoculation WT mice had a significantly greater neutrophil recruitment
into the alveolar space, determined by analysis of BAL, compared with
uPAR-/-
(p = 0.0003). Further, at 8 h the
uPAR-/- mice continued to
have markedly diminished neutrophil recruitment to the alveolar space
compared with WT mice (p = 0.0011). This work
demonstrates that the recruitment of neutrophils to the pulmonary
alveolar space in response to P. aeruginosa pneumonia is
dependent upon the expression of uPAR.
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10 times the number of neutrophils in response to P.
aeruginosa as did the
uPAR-/- mice
(p = 0.0001; n = 5). Thus, the
requirement for uPAR in neutrophil recruitment to the lung during
Pseudomonas pneumonia is independent of the protease
uPA. The uPAR-/- mice have impaired pulmonary clearance of P. aeruginosa compared with the WT mice
To determine whether the reduced neutrophil recruitment seen in
the uPAR-/- mice impaired
pulmonary clearance of the pathogen, WT and
uPAR-/- mice were IT
inoculated with P. aeruginosa as described above. Four hours
later the animals were sacrificed, and P. aeruginosa CFU was
determined. As shown in Fig. 2
B,
uPAR-/- mice had markedly
reduced P. aeruginosa clearance compared with WT mice
(6.43 ± 1.10 vs 3.05 ± 0.36 x
105 CFU; p = 0.027). The absence
of uPAR impairs P. aeruginosa clearance.
Anti-CD11b Ab diminishes neutrophil recruitment in WT mice, but not in uPAR-/- mice
To elucidate the mechanism of impaired neutrophil recruitment, we
next determined the effects of anti-CD11b (anti-CR3, Mac-1) mAb
on neutrophil recruitment in WT and
uPAR-/- mice. As
demonstrated in Fig. 3, pretreatment of
WT mice with the anti-CD11b mAb profoundly diminished neutrophil
recruitment at 4 h post-IT inoculation of P. aeruginosa
compared with that in control Ab-treated WT mice
(p = 0.0011). In contrast, pretreatment of
uPAR-/- mice with
anti-CD11b mAb had no effect on the number of neutrophils recruited
to the alveolar space compared with that in control Ab-treated
uPAR-/- mice (not
significant). The control animals in these experiments were treated
with rat IgG injection by tail vein 15 min before IT inoculation with
P. aeruginosa at the same dose as the anti-CD11b mAb.
From these data we conclude that blockade with an anti-CD11b mAb
profoundly diminishes the recruitment of neutrophils to the lung in
response to P. aeruginosa (a ß2
integrin-dependent pathogen) in WT mice, but has no effect on
neutrophil recruitment in
uPAR-/- mice. This
suggests the recruitment of neutrophils in response to P.
aeruginosa requires both uPAR and ß2
integrin expression, and that these two receptors act by a common
mechanism.
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As shown in Fig. 4A,
under low and high power photomicroscopy, the WT (A and
B) and uPAR-/-
(C and D) mice have similar pulmonary
architecture and cellular composition following PBS IT inoculation.
Inoculation with P. aeruginosa IT (Fig. 4B)
results in markedly different recruitment of neutrophils to the
pulmonary parenchyma comparing WT (A and B) and
uPAR-/- (C and
D) mice. As is clearly evident, WT mice have robust
recruitment of neutrophils to the alveolar parenchyma in response to
P. aeruginosa pneumonia. In contrast, there is little
evidence of inflammatory changes and markedly few neutrophils recruited
to the alveolar space in the
uPAR-/- mice. In Fig. 4C, high power photomicrographs clearly show the robust
recruitment of neutrophils to the alveolar space in the WT mice
(A) and the marked paucity of neutrophil recruitment in the
uPAR-/- mice
(B).
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To demonstrate that the inoculum of P. aeruginosa
widely dispersed in both the WT and
uPAR-/- mice, histologic
sections were subjected to Gram staining. As clearly evident (Fig. 5A, arrows), there are
organisms present at 4 h post-IT inoculation in the alveolar space
of WT mice. Further, the areas of Pseudomonas deposition are
accompanied by a robust inflammatory response, with marked recruitment
of neutrophils to the alveolar space and evidence of internalization of
the organisms by the neutrophils. In contrast, in the
uPAR-/- mice, sheets of
P. aeruginosa (Gram-negative rods) are evident within the
alveolar spaces (Fig. 5B, arrows); however, there is a
profound paucity of neutrophil recruitment to these areas despite the
heavy bacillary load in the alveolar spaces. Thus, the diminished
recruitment seen in the
uPAR-/- mice occurs
despite a large pathogen burden in the lung. These histologic data are
fully consistent with the diminished P. aeruginosa clearance
demonstrated by comparing CFU in
uPAR-/- and WT mice in
Fig. 2B.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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uPAR and CR3 associate on PMN and M cell membranes (9, 23). Previous in vitro work has demonstrated that uPAR plays an
obligate role in leukocyte chemotaxis. We have shown that treating
leukocytes with an anti-uPAR mAb or antisense oligonucleotides
against uPAR blocks chemotaxis (8, 11). This effect was
independent of uPA enzyme activity, because blocking the catalytic site
of uPA or, alternatively, saturating the cell surface with
catalytically active high molecular weight uPA had no effect on
chemotaxis (11). The importance of uPAR in cell migration
has been extended to many other cell types, including invasive breast
carcinoma, vascular smooth muscle cells, and endothelial cells
(24, 25, 26). The partnering of uPAR with CR3 also regulates
other CR3-mediated functions, such as adhesion (9). Thus,
uPAR is an important receptor in regulating cell movement in vitro and
does so, at least in leukocytes, by forming a modulatory
partner-protein interaction with CR3.
Cellular recruitment to sites of infection in vivo is far more complex than chemotaxis in vitro, as a variety of selectins and various adhesion molecules must be sequentially used and multiple tissue planes and matrix proteins traversed. The instillation of bacteria into the lung results in an acute inflammatory response, which includes the induction of expression of a plethora of chemokines and cytokines, and in complement activation. Determination of the mechanism of leukocyte recruitment to the lung in response to acute inflammation poses an unusual addition level of complexity, because in the lung, unlike other organs, the requirement for ß2 integrin activity varies depending on the recruitment stimulus (27, 28). Therefore, conclusions reached in other organ systems or in vitro regarding the requirement for specific receptors for leukocyte immigration may be irrelevant to lung biology. Selection of the infectious agent for the induction of pneumonia was critical in this study, because neutrophil recruitment even in response to various bacterial pathogens can be CR3 independent or CR3 dependent (29). We chose to study innate host defense against P. aeruginosa pneumonia for the following reasons: 1) recruitment is established to be CR3 dependent; 2) the model is well established, and recruitment parameters have been delineated in our laboratories; and 3) Pseudomonas pneumonia is of substantial clinical importance (15, 16, 21).
Our results corroborate the CR3 dependence of neutrophil recruitment in
response to P. aeruginosa, as demonstrated by the marked
diminution of recruitment seen in the anti-CR3 Ab-treated WT mice
(Fig. 3). We demonstrate the novel finding that
uPAR-/- mice have reduced
neutrophil recruitment in response to the pathogen, similar to
anti-CR3 Ab-treated WT mice. This markedly diminished recruitment
is demonstrated by the paucity of neutrophils recruited to the alveolar
space and quantified in BAL at 4 and 8 h post-IT inoculation (Fig. 2A). Histologically, while the WT and
uPAR-/- mice have lungs
that appear to be identical when uninfected (Fig. 4A), the
utter lack of neutrophil response in the
uPAR-/- mice compared
with the WT response to infection at 4 h post-IT inoculation is
striking (Fig. 4, B and C). This difference is
not due to inhomogeneity of the bacillary inoculum, as on histologic
Gram staining it is clearly evident that the
uPAR-/- mice fail to
recruit neutrophils to regions of the lung with a substantial pathogen
burden, while WT mice respond with robust neutrophil recruitment
(Fig. 5).
uPAR-/- neutrophil
recruitment is not further reduced by anti-CR3-Ab treatment,
suggesting that uPAR and CR3 participate in recruitment by a common
mechanism (Fig. 3). The similarity of recruitment seen in the
uPAR-/- mice and the
anti-CR3 Ab-treated WT mice has substantial implications for our
understanding of integrin biology. It is interesting that the genetic
deletion of uPAR impairs CR3-mediated neutrophil recruitment, while the
genetic deletion of CD18 itself results in an animal with an unknown
compensatory mechanism for lung neutrophil recruitment in response to
classic CR3-dependent stimuli (30, 31). This would suggest
that manipulation of an integrin "partner protein" may be an
efficacious target for therapeutic modulation of integrin function.
The role of uPAR in neutrophil recruitment is independent of uPA in this model. Neutrophil recruitment in the uPA-/- mice was no different from that in WT mice and was 10-fold more than recruitment in uPAR-/- mice. This suggests that the proteolytic activity of uPA, a serine protease, is not required for neutrophil recruitment to the lung. This is not surprising. Although neutrophils express many potent proteases capable of matrix degradation, the requirement for proteases (particularly serine proteases) in neutrophil emigration is disputed by some studies and remains controversial (32). The current observation is also consistent with our previous studies using uPA-/- mice. We have shown that the number of lung Mac1+ cells at times points classic for neutrophil recruitment in response to C. neoformans IT inoculation and the number of neutrophils recruited to the lung in response to P. carinii pneumonia were no different from those in WT mice (19, 33). These results are contrary to some previous work investigating the role of uPA in chemotaxis, where a uPA-dependent conformational charge was found to be induced in uPAR uncovering a chemotactic epitope. The uPA binding in this chemotaxis model is thought to transform uPAR into a pleiotropic ligand for other still unidentified cell surface molecules, which then cause cytoskeletal changes, activation of kinases, and directional cell migration (34). Apparently none of these effects of uPA on uPAR is required for cell recruitment in our in vivo model. Since the above-described conformational change in uPAR also occurs on cleavage between uPAR domains D1 and D2, (a known uPA cleavage site) (34), an alternative possibility is that a protease other than uPA may cleave uPAR between domains D1 and D2, thus activating uPAR in a uPA-independent manner.
Although our work demonstrates that uPA is not required for neutrophil
recruitment to the lung, uPA may still play a role in pulmonary host
defense against P. aeruginosa. The binding of uPA to uPAR
generates signals that enhance cellular activation, inducing serine
phosphorylation in epithelial cells (35), activation of
the Jak/Stat1 pathway and induction of Src-like protein tyrosine
kinases in smooth muscle cells (36), and tyrosine
phosphorylation in a macrophage cell line (37). Although
this study was designed to evaluate recruitment, we observed that while
the uPA-/- mice recruited
neutrophils comparably to the WT mice, the uPA mice tended to have
higher CFUs than the WT mice (5.9 ± 1.7 vs 3.05 ± 0.4
x 105), although statistical significance was
not reached. This suggests that antibacterial neutrophil activation is
impaired in the absence of uPA. This observation is consistent with the
in vitro demonstration that uPA binding to uPAR primed neutrophils for
superoxide anion release (10). By contrast,
Pseudomonas clearance is severely reduced in the
uPAR-/- mice
(p = 0.027). This is probably due, firstly, to
the paucity of neutrophils recruited in response to the bacillary
challenge (Fig. 5) and, secondly, to the loss of uPAR-mediated
activation signaling.
In summary, this study demonstrates that uPAR is necessary for normal neutrophil recruitment to the lung in response to the clinically relevant pathogen P. aeruginosa. The requirement for uPAR in this system is independent of the protease uPA, its natural ligand; further, we show that uPAR shares a common functional mechanism with CR3. This is the first study demonstrating a role for uPAR in innate pulmonary host defenses in vivo. This work suggests that manipulation of uPAR expression or function may be a target for immunomodulation.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Margaret R. Gyetko, 3916 Taubman Center, Medical Center Drive, Ann Arbor, MI 48109-0360.
3 Abbreviations used in this paper: uPA, urokinase; uPAR, uPA receptor; CR3, CD1b/CD18; M, macrophage; WT, wild type; BAL, bronchoalveolar lavage; IT, intratracheal.
Received for publication March 20, 2000. Accepted for publication May 18, 2000.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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mß2, CD11b/CD18) and FC
RIII cooperate in generation of a neutrophil respiratory bust: requirement for FcRII and tyrosine phosphorylation. J. Cell Biol. 125:1407.This article has been cited by other articles:
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E. East, D. Baker, G. Pryce, H. R. Lijnen, M. L. Cuzner, and D. Gveric A Role for the Plasminogen Activator System in Inflammation and Neurodegeneration in the Central Nervous System during Experimental Allergic Encephalomyelitis Am. J. Pathol., August 1, 2005; 167(2): 545 - 554. [Abstract] [Full Text] [PDF]
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B. Degryse, M. Resnati, R.-P. Czekay, D. J. Loskutoff, and F. Blasi Domain 2 of the Urokinase Receptor Contains an Integrin-interacting Epitope with Intrinsic Signaling Activity: GENERATION OF A NEW INTEGRIN INHIBITOR J. Biol. Chem., July 1, 2005; 280(26): 24792 - 24803. [Abstract] [Full Text] [PDF]
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 T. J. Koh, S. C. Bryer, A. M. Pucci, and T. H. Sisson Mice deficient in plasminogen activator inhibitor-1 have improved skeletal muscle regeneration Am J Physiol Cell Physiol, July 1, 2005; 289(1): C217 - C223. [Abstract] [Full Text] [PDF]
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 N. Shushakova, N. Tkachuk, M. Dangers, S. Tkachuk, J.-K. Park, K. Hashimoto, H. Haller, and I. Dumler Urokinase-induced activation of the gp130/Tyk2/Stat3 pathway mediates a pro-inflammatory effect in human mesangial cells via expression of the anaphylatoxin C5a receptor J. Cell Sci., June 15, 2005; 118(12): 2743 - 2753. [Abstract] [Full Text] [PDF]
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R. T. Sadikot, T. S. Blackwell, J. W. Christman, and A. S. Prince Pathogen-Host Interactions in Pseudomonas aeruginosa Pneumonia Am. J. Respir. Crit. Care Med., June 1, 2005; 171(11): 1209 - 1223. [Abstract] [Full Text] [PDF]
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C. J. G. de Almeida, L. B. Chiarini, J. P. da Silva, P. M. R. e Silva, M. A. Martins, and R. Linden The cellular prion protein modulates phagocytosis and inflammatory response J. Leukoc. Biol., February 1, 2005; 77(2): 238 - 246. [Abstract] [Full Text] [PDF]
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J. R. Schurr, E. Young, P. Byrne, C. Steele, J. E. Shellito, and J. K. Kolls Central Role of Toll-Like Receptor 4 Signaling and Host Defense in Experimental Pneumonia Caused by Gram-Negative Bacteria Infect. Immun., January 1, 2005; 73(1): 532 - 545. [Abstract] [Full Text] [PDF]
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A. de Paulis, N. Montuori, N. Prevete, I. Fiorentino, F. W. Rossi, V. Visconte, G. Rossi, G. Marone, and P. Ragno Urokinase Induces Basophil Chemotaxis through a Urokinase Receptor Epitope That Is an Endogenous Ligand for Formyl Peptide Receptor-Like 1 and -Like 2 J. Immunol., November 1, 2004; 173(9): 5739 - 5748. [Abstract] [Full Text] [PDF]
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M. R. Gyetko, D. Aizenberg, and L. Mayo-Bond Urokinase-deficient and urokinase receptor-deficient mice have impaired neutrophil antimicrobial activation in vitro J. Leukoc. Biol., September 1, 2004; 76(3): 648 - 656. [Abstract] [Full Text] [PDF]
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S. L. Mueller-Ortiz, S. M. Drouin, and R. A. Wetsel The Alternative Activation Pathway and Complement Component C3 Are Critical for a Protective Immune Response against Pseudomonas aeruginosa in a Murine Model of Pneumonia Infect. Immun., May 1, 2004; 72(5): 2899 - 2906. [Abstract] [Full Text] [PDF]
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M. R. Gyetko, S. Sud, and S. W. Chensue Urokinase-Deficient Mice Fail To Generate a Type 2 Immune Response following Schistosomal Antigen Challenge Infect. Immun., January 1, 2004; 72(1): 461 - 467. [Abstract] [Full Text] [PDF]
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N. Beaufort, D. Leduc, J.-C. Rousselle, V. Magdolen, T. Luther, A. Namane, M. Chignard, and D. Pidard Proteolytic Regulation of the Urokinase Receptor/CD87 on Monocytic Cells by Neutrophil Elastase and Cathepsin G J. Immunol., January 1, 2004; 172(1): 540 - 549. [Abstract] [Full Text] [PDF]
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J. L. Coleman and J. L. Benach The Urokinase Receptor Can Be Induced by Borrelia burgdorferi through Receptors of the Innate Immune System Infect. Immun., October 1, 2003; 71(10): 5556 - 5564. [Abstract] [Full Text] [PDF]
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Y. Li, D. A. Lawrence, and L. Zhang Sequences within Domain II of the Urokinase Receptor Critical for Differential Ligand Recognition J. Biol. Chem., August 8, 2003; 278(32): 29925 - 29932. [Abstract] [Full Text] [PDF]
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J. Sato, J. Schorey, V. A. Ploplis, E. Haalboom, L. Krahule, and F. J. Castellino The Fibrinolytic System in Dissemination and Matrix Protein Deposition During a Mycobacterium Infection Am. J. Pathol., August 1, 2003; 163(2): 517 - 531. [Abstract] [Full Text] [PDF]
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A. W. Rijneveld, S. Florquin, P. Bresser, M. Levi, V. de Waard, R. Lijnen, J. S. Van der Zee, P. Speelman, P. Carmeliet, and T. van der Poll Plasminogen activator inhibitor type-1 deficiency does not influence the outcome of murine pneumococcal pneumonia Blood, August 1, 2003; 102(3): 934 - 939. [Abstract] [Full Text] [PDF]
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E. Abraham, M. R. Gyetko, K. Kuhn, J. Arcaroli, D. Strassheim, J. S. Park, S. Shetty, and S. Idell Urokinase-Type Plasminogen Activator Potentiates Lipopolysaccharide-Induced Neutrophil Activation J. Immunol., June 1, 2003; 170(11): 5644 - 5651. [Abstract] [Full Text] [PDF]
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 G. Zhang, H. Kim, X. Cai, J. M. Lopez-Guisa, P. Carmeliet, and A. A. Eddy Urokinase Receptor Modulates Cellular and Angiogenic Responses in Obstructive Nephropathy J. Am. Soc. Nephrol., May 1, 2003; 14(5): 1234 - 1253. [Abstract] [Full Text] [PDF]
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E. Pluskota, D. A. Soloviev, and E. F. Plow Convergence of the adhesive and fibrinolytic systems: recognition of urokinase by integrin alpha Mbeta 2 as well as by the urokinase receptor regulates cell adhesion and migration Blood, February 15, 2003; 101(4): 1582 - 1590. [Abstract] [Full Text] [PDF]
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 E. M. Powell, D. B. Campbell, G. D. Stanwood, C. Davis, J. L. Noebels, and P. Levitt Genetic Disruption of Cortical Interneuron Development Causes Region- and GABA Cell Type-Specific Deficits, Epilepsy, and Behavioral Dysfunction J. Neurosci., January 15, 2003; 23(2): 622 - 631. [Abstract] [Full Text] [PDF]
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Y. Xia, G. Borland, J. Huang, I. F. Mizukami, H. R. Petty, R. F. Todd III, and G. D. Ross Function of the Lectin Domain of Mac-1/Complement Receptor Type 3 (CD11b/CD18) in Regulating Neutrophil Adhesion J. Immunol., December 1, 2002; 169(11): 6417 - 6426. [Abstract] [Full Text] [PDF]
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A. E. May, R. Schmidt, S. M. Kanse, T. Chavakis, R. W. Stephens, A. Schomig, K. T. Preissner, and F.-J. Neumann Urokinase receptor surface expression regulates monocyte adhesion in acute myocardial infarction Blood, November 15, 2002; 100(10): 3611 - 3617. [Abstract] [Full Text] [PDF]
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 A. A. Eddy Plasminogen activator inhibitor-1 and the kidney Am J Physiol Renal Physiol, August 1, 2002; 283(2): F209 - F220. [Abstract] [Full Text] [PDF]
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A. W. Rijneveld, M. Levi, S. Florquin, P. Speelman, P. Carmeliet, and T. van der Poll Urokinase Receptor Is Necessary for Adequate Host Defense Against Pneumococcal Pneumonia J. Immunol., April 1, 2002; 168(7): 3507 - 3511. [Abstract] [Full Text] [PDF]
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S. Suzuki, M. Kobayashi, K. Chiba, I. Horiuchi, J. Wang, T. Kondoh, S. Hashino, J. Tanaka, M. Hosokawa, and M. Asaka Autocrine production of epithelial cell-derived neutrophil attractant-78 induced by granulocyte colony-stimulating factor in neutrophils Blood, March 1, 2002; 99(5): 1863 - 1865. [Abstract] [Full Text] [PDF]
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M. R. Gyetko, S. Sud, J. Sonstein, T. Polak, A. Sud, and J. L. Curtis Cutting Edge: Antigen-Driven Lymphocyte Recruitment to the Lung Is Diminished in the Absence of Urokinase-Type Plasminogen Activator (uPA) Receptor, but Is Independent of uPA J. Immunol., November 15, 2001; 167(10): 5539 - 5542. [Abstract] [Full Text] [PDF]
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J.-i. Nishimura, K. L. Phillips, R. E. Ware, S. Hall, L. Wilson, T. L. Gentry, T. A. Howard, Y. Murakami, M. Shibano, T. Machii, et al. Efficient retrovirus-mediated PIG-A gene transfer and stable restoration of GPI-anchored protein expression in cells with the PNH phenotype Blood, May 15, 2001; 97(10): 3004 - 3010. [Abstract] [Full Text] [PDF]
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L. Kjoller and A. Hall Rac Mediates Cytoskeletal Rearrangements and Increased Cell Motility Induced by Urokinase-Type Plasminogen Activator Receptor Binding to Vitronectin J. Cell Biol., March 19, 2001; 152(6): 1145 - 1158. [Abstract] [Full Text] [PDF]
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 M. Resnati, I. Pallavicini, J. M. Wang, J. Oppenheim, C. N. Serhan, M. Romano, and F. Blasi The fibrinolytic receptor for urokinase activates the G protein-coupled chemotactic receptor FPRL1/LXA4R PNAS, February 5, 2002; 99(3): 1359 - 1364. [Abstract] [Full Text] [PDF]
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, WT mice; 
,
uPAR-/-. Data are expressed as the mean
± SEM. *, p = 0.0088 (n =
14).
