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* Division of Respiratory Medicine, City Hospital, University of Nottingham, Nottingham, United Kingdom
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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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Prostanoid synthesis is mediated by two isoforms of COX, the constitutive COX-1 and the inducible COX-2, whose expression is regulated by cytokines (21). Reports from synovial fibroblasts showing that derived CSFs are modulated by endogenous and exogenous prostanoids (22, 23) suggest that prostanoids, in addition to their role as inflammatory mediators, may be important modulators of cytokine production. Although increased prostanoid release following COX-2 induction in cultured human ASM cells has recently been reported (18, 19, 20), the effect of prostanoids on cytokine release in human ASM cells has not been investigated.
Bradykinin (BK), which is a potent inflammatory mediator in patients with bronchial asthma (24, 25, 26), has recently been shown to stimulate cytokine expression. BK increases the expression of IL-1ß, IL-2, and IL-6 from isolated guinea pig lung strips (27), IL-1ß from cultured human fibroblasts (28), and IL-8 from human decidua-derived cells (29). Recently, we have reported that BK, like IL-1ß, causes the induction of COX-2 and the release of prostanoids from human ASM cells (19). Since IL-1ß reportedly causes IL-8 release from human ASM cells (16) and PGE2 enhances IL-8 and IL-6 production by IL-1-stimulated human synovial fibroblasts (23), we postulated that BK might also cause IL-8 release from human ASM cells, and that the high concentration of prostanoids following COX-2 induction could play a modulating role in this process.
The present study investigated whether BK could cause IL-8 production in human ASM cells and determined whether COX products and COX-2 isoenzyme induction were involved in this process.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Human tracheas were obtained from two postmortem individuals (one 44-yr-old male and one 52-yr-old female) within 12 h of death; neither individual had any evidence of airway diseases. Primary cultures of human ASM cells were prepared from explants of ASM according to previously reported methods (18, 19). Cells at passage three to four were used for all experiments. We have shown previously that cells grown in this manner depict the immunohistochemical and light microscopic characteristics of typical ASM cells (18).
Experiment protocol
The cells were cultured to confluence in 10% FCS (Seralab, Crowly Down, U.K.)/DMEM (Sigma, Poole, U.K.) in humidified 5% CO2/95% air at 37°C in 24-well culture plates and growth-arrested in serum-deprived medium for 24 h before experiments. Immediately before each experiment, fresh serum-free medium containing BK (Sigma) was added. In the time-course experiments, the cells were incubated with BK (10 µM) for 1 to 24 h, whereas in the concentration response experiments, the cells were incubated for 16 h with 0.01 to 100 µM of BK. In most experiments thereafter, the cells were incubated with 10 µM of BK for 16 h. At the indicated times, the culture media were harvested and stored at -20°C until the RIA for PGE2 content as a representative of prostanoid generation (18) and/or an ELISA for IL-8. The anti-PGE2 antiserum (Sigma) had negligible cross-reactivity in our study (18). To test the inhibition of various drugs on the effect of BK, the nonselective COX inhibitors indomethacin (IND) and flurbiprofen (FLU), the protein synthesis inhibitors cycloheximide (CHX) and actinomycin D (ACT), the antiinflammatory steroid dexamethasone (DEX), the B1 receptor antagonist desArg9, (Leu8)-BK (Sigma), the selective COX-2 inhibitor NS-398 (N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulfonamide) (Cayman Chemical, Ann Arbor, MI), and the B2 receptor antagonist DArg(Hyp3,Thi5,Dtic7,Oic8)-BK (HOE-140) (a kind gift of Drs. R. N. Zahlten and B. A. Scholkens, Hoechst Aktiengesellschaft, Frankfurt, Germany) were added 30 min before the addition of BK. Experiments with the selective BK B1 receptor agonist desArg9-BK, the B2 receptor agonist (Tyr(Me)8)-BK, COX substrate arachidonic acid (AA), calcium ionophore A23187, and exogenous PGE2 (all from Sigma) were conducted in the same way as those for BK.
IL-8 assay
The concentration of IL-8 in the culture medium was determined
by ELISA (CLB, Amsterdam, The Netherlands) according to the
manufacturer’s instructions. Briefly, ELISA plates were coated
overnight at room temperature with 200 µL of anti-human
IL-8-coating Ab that had been diluted in 0.1 M carbonate/bicarbonate
buffer (pH 9.6). Plates were then washed five times with PBS (pH
7.2–7.4) containing 0.05% Tween 20 and blocked for 1 h at room
temperature with 200 µL of blocking buffer. Plates were washed again,
and 100 µL of samples containing standard amounts of human rIL-8 as
well as study samples were added in duplicate to individual wells and
incubated at room temperature for 1 h. After five washes, 100 µL
of biotinylated IL-8 Ab diluted in dilution buffer was added for 1
h. After another five washes, 100 µL of streptavidin-horseradish
peroxidase (HRP) conjugate that had been diluted to 1/10,000 in
dilution buffer was added for 30 min. After a final wash, 100 µL of
the substrate buffer containing the HRP substrate tetramethylbenzidine
dihydrochloride and hydrogen peroxide in 0.05 M phosphate-citrate
buffer (pH 5.0) was added for 30 min in the dark and color-developed in
proportion to the amount of IL-8 present. The reaction was stopped by
adding 100 µL of stop solution (1.8 M sulfuric acid), and the degree
of color that had been generated was determined by measuring the OD at
450 nm in a Dynatech MR5000 microplate reader (Billinghurst, U.K.). The
standard curve was linearized and subjected to regression analysis. The
IL-8 concentration of unknown samples was extracted using the standard
curve. The results were expressed as picograms per milliliter of
culture medium. The sensitivity of the ELISA kit in our study was at
least 5 pg/ml, which was consistent with the manufacturer’s
specifications. According to the kit insert, the anti-IL-8 Ab does
not cross-react with IL-1 through IL-7, IL-9 through IL-11, TNF,
IFN-
, GM-CSF, and RANTES. All of the reagents used in the assay were
supplied by the ELISA manufacturer, with the exception of the HRP
substrate tetramethylbenzidine dihydrochloride, which was obtained from
Sigma.
Cell viability
The toxicity of all the chemicals used in this study as well as their vehicles (dimethyl sulfoxide and ethanol) (Sigma, final concentration 1.0% v/v) to human ASM cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (18, 19). After a 24-h incubation with the chemicals, 20 µl of 5 mg/ml thiazolyl blue (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (Sigma) was added to the culture medium in 96-well plates and incubated for 1 h at 37°C. After removing the medium, 200 µl of DMSO was added to solubilize the blue-colored tetrazolium, the plates were shaken for 5 min, and the OD550 values were read in a Dynatech MR5000 microplate reader. Viability was set as 100% in control cells.
Statistical analysis
Data were expressed as the mean ± SEM from n determinations. The statistical analysis was performed using the statistical software from SPSS Inc. (Chicago, IL) (30). A one-way ANOVA and/or an unpaired, two-tailed Student’s t test were used to determine the significant differences between the means. The results were adjusted for multiple testing using Bonferroni’s correction. p values of <0.05 were accepted as statistically significant.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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To investigate the time course of IL-8 production, human ASM cells
were cultured in the presence or absence of BK (10 µM). Cell culture
supernatants from control cells were collected at 2, 8, and 24 h;
supernatants from BK-treated cells were collected at 0.25, 0.5, 1, 2,
4, 8, 16, and 24 h. As shown in Figure 1
A, basal (0 h) IL-8 release
was 5.92 pg/ml. There was a slight increase in IL-8 production from
control cells over the 24-h incubation (6.15 pg/ml at 2 h, 6.48
pg/ml at 8 h, and 11.34 pg/ml at 24 h). There was a marked
and time-dependent increase in IL-8 release following stimulation with
BK; a significant difference was observed after 2 h of stimulation
as compared with IL-8 production from control cells
(p < 0.01), and the highest IL-8 concentration
was achieved after 16 h of stimulation (p
< 0.001). When the cells were cultured with BK at concentrations of
0.01, 0.1, 1.0, 10, and 100 µM for 16 h, a
concentration-dependent increase in IL-8 production was also observed
that was significant from 0.01 µM (p <
0.001) (Fig. 1B).
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The effect of the nonselective COX inhibitor IND, the selective
COX-2 inhibitor NS-398, the protein synthesis inhibitors CHX and ACT,
and the steroid DEX was assessed on BK-induced PGE2 release
and IL-8 production from human ASM cells. As shown in Figure 2A, BK (10 µM) caused a
marked increase in PGE2 release; this increase was
inhibited in a strong and concentration-dependent manner by both IND
and NS-398 and was abolished at a concentration of 10 µM.
Interestingly, BK-induced IL-8 production was also markedly inhibited
by the same concentration range of IND and NS-398 in a
concentration-dependent fashion, although production could not be
abolished by either inhibitor (Fig. 2B); this finding
suggests that BK-induced IL-8 production is mediated by the COX
products, including those from the inducible COX-2 isoform, after BK
treatment. We have shown before that BK-induced long-term (4 h)
PGE2 release and COX-2 induction are inhibited by CHX, ACT,
and DEX (19); BK-induced IL-8 production was also abolished by
CHX, ACT, and DEX in this past study (all 1.0 µM, Fig. 3).
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If COX products are involved in BK-stimulated IL-8 production,
then such products should be able to cause IL-8 production on their
own. To prove this, we examined whether the exogenously applied COX
substrate AA, which was in turn converted to prostanoids by the
existing COX-1, could result in similar IL-8 production from these
cells. Human ASM cells were cultured in the presence of AA (10 µM),
and cell culture supernatants were collected at 0, 1, 2, 4, 8, 12, 16,
20, and 24 h. As shown in Figure 4A, there was a time-dependent
accumulation of PGE2 that became significant after
1 h (p < 0.01) and peaked after 12 h
of treatment (p < 0.001). When the cells were
treated with AA at concentrations of 0.01, 0.1, 1.0, 10, and 100 µM
for 16 h, a concentration-dependent increase in PGE2
generation was also observed; this increase was significant from 0.01
µM (p < 0.05), and the highest concentration
was obtained at 100 µM (p < 0.001, Fig. 4B). In the meantime, AA also stimulated IL-8 production in
a time- and concentration-dependent manner (Fig. 5, A and B) that
was similar to that seen for PGE2 generation; however, in
the time course studies, the highest concentration of IL-8 was observed
after 16 h of treatment, which was 4 h later than the time at
which the highest concentration was observed for
PGE2.
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To investigate whether COX products mediated the effect of AA on
IL-8 production, we studied the effect of two of the nonselective COX
inhibitors IND and FLU as well as other inhibitors such as NS-398, CHX,
ACT, and DEX on AA-induced PGE2 and IL-8 production from
human ASM cells. AA (10 µM) markedly increased PGE2
release, while both IND and FLU inhibited the increase in a strong and
concentration-dependent fashion and abolished it at a concentration of
10 µM (Fig. 6A). Conversely,
NS-398, CHX, ACT, and DEX (all 1 µM) had no significant
effect on the increase, as shown in Figure 6B. These results
suggest that only the constitutive COX-1 isoenzyme is involved in
converting AA to prostanoids. Again, the same concentration range of
IND and FLU also markedly inhibited AA-induced IL-8 production in a
concentration-dependent fashion but did not abolish its effect (Fig. 7A). In addition, NS-398, had
no effect on AA induced IL-8 generation, similar to its ineffectiveness
on PGE2 release. However, CHX, ACT, and DEX suppressed IL-8
production (Fig. 7B), suggesting that AA-induced IL-8
production is mediated by COX products from the COX-1 isoform and that
the modulation of IL-8 expression by COX products is at the IL-8 gene
transcription level.
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To further clarify the role of COX products in BK-induced IL-8
production, we examined whether exogenously applied PGE2
and calcium ionophore A23187, which has a similar effect to BK in
causing free calcium increase and the release of endogenous AA, could
result in similar IL-8 production. As shown in Figure 8, PGE2 (1.0 µM) caused a
sixfold increase in IL-8 production. A23187 was found to cause a
concentration-dependent generation of PGE2 after a 16-h
incubation with human ASM cells. The maximum effect was observed with
10 µM of A23187, with which a 16-fold increase over basal
PGE2 was obtained (data not shown) and a nearly 18-fold
increase of IL-8 production was also achieved (Fig. 8). Like
that with AA, the IL-8 increase was strongly inhibited by IND, CHX,
ACT, and DEX. These results consequently provide further evidence that
COX products can cause IL-8 production from human ASM cells and are
mainly responsible for the IL-8 production caused by BK.
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To characterize the BK receptor(s) involved in BK-induced IL-8
production, we examined the effect of the selective BK B1
receptor agonist desArg9-BK and the selective
B2 receptor agonist (Tyr(Me)8)-BK on this
event. (Tyr(Me)8)-BK mimicked the effect of BK by causing
IL-8 production in a concentration-dependent manner that was similar to
that seen for BK; the increase was significant from 0.01 µM
(p < 0.001), and maximum effect was observed
at 1.0 µM (p < 0.001) (Fig. 9). In contrast, pretreating the cells
with the B1 receptor agonist desArg9-BK had
only a weak effect on IL-8 formation at high concentrations; this
effect was significant from 1.0 µM (p
< 0.01) and reached a peak at 10 µM (p <
0.001) as compared with the control cells (Fig. 9). These results
suggest that the B2 receptor is responsible for the effect.
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Pretreating human ASM cells with the selective B2
receptor antagonist HOE-140 (1–100 µM) strongly antagonized BK (10
µM)-induced IL-8 production in a concentration-dependent fashion and
abolished the effect of BK at 10 and 100 µM (Fig. 10); Over half (53%) of IL-8
production was inhibited by 0.1 µM HOE-140, and the IL-8
concentration was 138.67 ± 9.07 pg/ml. However, pretreatment with
the B1 receptor antagonist
desArg9,(Leu8)-BK over the same concentration
range did not show any significant effect (Fig. 10). Therefore, these
data provide further evidence that B2 receptors are
responsible for mediating BK-induced IL-8 production from human ASM
cells.
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Cell viability after 16 h (some 24 h) of treatment with
most of the chemicals used in this study was consistently >95%
compared with cells that had been treated with the vehicles. However,
the viability was reduced to 
90% after the cells were treated with
100 µM of BK or 100 µM of AA for 16 h; therefore, 10 µM for
both BK and AA was chosen for additional experiments in this study.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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We found that stimulating human ASM cells with BK resulted in a time- and concentration-dependent release of IL-8 protein. ASM cells have long been studied largely from the perspective of target cells whose contractile and proliferational states are altered by local inflammatory events underlying the pathogenesis of asthma. Recently, however, a growing body of data has emerged to support the notion that human ASM cells have the potential to act as effector cells in perpetuating airway inflammation by expressing and secreting inflammatory products including prostanoids (18, 19, 20) and cytokines such as GM-CSF (15), IL-11, IL-6 (16), and RANTES (17). Our present observations that BK and AA cause IL-8 production from human ASM cells provide further evidence to support this notion. Thus, ASM may contribute directly to the recruitment of inflammatory cells such as neutrophils and eosinophils to the airways.
The most interesting finding of our study was that BK-induced IL-8 release was dependent upon COX products. This has not been previously reported in any cell system and may be relevant to the mechanism of action of BK in inflammatory diseases. Both the nonselective COX inhibitor IND and the selective COX-2 inhibitor NS-398 inhibited not only BK-induced prostanoid generation but also BK-induced IL-8 production in a similar manner. These findings were strengthened by experiments showing that the COX substrate AA alone also mimicked the effect of BK on prostanoid and IL-8 release; like that of BK, the effect of AA was also strongly inhibited by nonselective COX inhibitors as well as the protein synthesis inhibitors CHX and ACT and the steroid DEX. The effect of CHX, ACT, and DEX on BK- and AA-induced IL-8 release is likely to represent an effect on the transcription and translation of the IL-8 gene itself rather than an effect on COX-2 induction, since AA alone does not induce COX-2. The effectiveness of NS-398 on BK-induced prostanoid and IL-8 production and the ineffectiveness of NS-398 on AA-induced prostanoid and IL-8 production can be explained by the induction of COX-2 in BK- but not AA-treated human ASM cells. Since we have recently reported the details regarding BK-stimulated PGE2 release and COX-2 induction in human ASM cells (19), Western blot results were not shown here. Our previous study showed that BK causes early PGE2 release from constitutive COX-1 followed by later PGE2 release due to COX-2 induction (19). We did not see a biphasic response with IL-8 production, which may reflect the time lag involvement in transcription and translation. The time allowance for the transcription and translation processes of IL-8 production could also explain why the peak for IL-8 release was 4 h later than that for PGE2 release after AA treatment. The fact that IND produced a greater effect than NS-398 in the present study suggests that the prostanoids produced by constitutive COX-1 isoenzyme, in addition to those produced by inducible COX-2, play a role in BK-induced IL-8 production. Therefore, our findings provide the first direct evidence that BK induces IL-8 expression in human ASM cells and that COX products and COX-2 induction contribute to this process.
Although it has been well documented that cytokines can act as stimuli for IL-8 expression, the effect of other stimuli on IL-8 production is poorly understood. A limited number of reports have shown that calcium ionophore (31), ß-adrenoceptor agonist isoproterenol (ISO) (32), and leukotriene (LT) B4 (33) stimulate IL-8 release from various cell systems. Only one previous study has shown that BK can release IL-8; however, the study examined human decidua-derived cells and did not characterize the mechanism(s) involved (29). Our finding that BK can induce IL-8 production in airway cells may be of great relevance for asthma. In the present study, we used selective B1 and B2 receptor agonists and antagonists to show that BK causes IL-8 production via the B2 receptor. This observation is consistent with the report that the BK-stimulated synthesis of IL-1ß, IL-2, and IL-6 from isolated lung strips can be blocked by a B2 receptor antagonist (27) and is also consistent with our previous study showing that the BK-mediated induction of COX-2 and the release of prostanoids from human ASM cells was mediated by the B2 receptor (19). Therefore, B2 receptor antagonists may play a role in controlling asthmatic airway inflammation.
Although the precise mechanisms of the effect of BK on IL-8 release are
not fully understood, the results of our current study clearly
demonstrate that prostanoid generation largely mediates the process.
Prostanoids are generated by the oxidation of AA by COX. They are
multifunctional mediators, but little is known about their effect on
cytokine production. A recent report has shown that PGE2
alone has little effect on IL-8 or GM-CSF but enhances IL-6 expression
in human synovial fibroblasts; PGE2 and iloprost
(PGI2 analogue) also enhance IL-8 production in
IL-1
-stimulated cells (23). Our present study is the first to
show that both endogenous (from AA) and exogenous prostanoids
(PGE2) directly cause IL-8 release from human ASM cells;
their mechanism(s), however, remain to be investigated. It is known
that the ß-adrenoceptor agonist ISO enhances IL-8 release in airway
epithelial cells via an increase in intracellular cAMP (32); our
preliminary study has also shown increased IL-8 release after ISO
stimulation of human ASM cells (our unpublished observations).
Prostanoids (mainly PGE2 and PGI2) activate the
PG EP2 and EP4 receptors that, like ß-adrenoceptors, are coupled to
adenylyl cyclase to increase intracellular cAMP production in human ASM
cells (34). Thus, prostanoids share a similar receptor-mediated signal
transduction system with ß-adrenoceptor agonists. Consequently, it is
reasonable to speculate that prostanoid-induced IL-8 release also
occurs via the increase of intracellular cAMP. The same mechanism may
also apply to IL-8 production caused by calcium ionophore (Ref. 31 and
this study), because it also increases prostanoid generation. BK
clearly alters airway function by several mechanisms that are in
addition to the COX product-mediated effects on IL-8 seen in our paper.
These include the stimulation of neural pathways and nitric
oxide release. The relative role of these mechanisms remains to
be elucidated.
Nonselective COX inhibitors were only partially effective on BK- (IND)
and AA- (IND and FLU) induced IL-8 production (maximum inhibition of
80% for both inhibitors) despite completely blocking
PGE2 release from human ASM cells; this observation
suggests that other products of AA may also be involved. The other
major pathway for AA metabolism, apart from the COX pathway, is the
generation of LTs via lipoxygenase. Inhibiting the COX pathway with COX
inhibitors may result in the shunting of AA to the lipoxygenase pathway
to produce more LTs. One of the major lipoxygenase products,
LTB4, possesses neutrophil chemotactic properties and has
been shown to stimulate human polymorphonuclear leukocytes to
synthesize and release IL-8 (33). Our preliminary investigation has
also unveiled that exogenous LTB4 alone induces IL-8
expression in a concentration-dependent manner with greater magnitude
as compared with the same concentration of exogenous PGE2
(our unpublished observations). Thus, it is likely that
lipoxygenase products, to some extent, also mediate BK- and AA-induced
IL-8 production in human ASM cells. Additional studies are needed to
explore the lipoxygenase pathway of AA metabolism in human ASM cells
under both resting and stimulated conditions.
In summary, this study examined the role of COX-2 induction and COX products in BK-induced IL-8 production in human ASM cells. Our results demonstrate that: 1) BK caused IL-8 production in cultured human ASM cells, and the effect was strongly inhibited by both nonselective and selective COX-2 inhibitors; 2) the COX substrate AA alone also stimulated IL-8 expression in a pattern that was similar to that seen for BK; 3) exogenously applied PGE2 and calcium ionophore A23187 also caused IL-8 release; and 4) BK-induced IL-8 production was mimicked and abolished by a selective B2 receptor agonist and antagonist, respectively. Collectively, these findings indicate that endogenous COX products, including those from COX-2 induction, are critically involved in mediating BK-induced IL-8 production in human ASM cells, and that human ASM may contribute directly to the recruitment of inflammatory cells in the airway and play a critical role in asthma pathogenesis. The mechanisms may be important in a number of other inflammatory diseases in which BK acts as a mediator.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Alan J. Knox, City Hospital, University of Nottingham, Hucknall Road, Nottingham NG5 1PB, U.K.
3 Abbreviations used in this paper: ASM, airway smooth muscle; GM-CSF, granulocyte-macrophage CSF; COX, cyclooxygenase; AA, arachidonic acid; BK, bradykinin; IND, indomethacin; CHX, cycloheximide; ACT, actinomycin D; DEX, dexamethasone; FLU, flurbiprofen; HRP, horseradish peroxidase; ISO, isoproterenol; LT, leukotriene.
Received for publication February 11, 1998. Accepted for publication April 27, 1998.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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and interferon- on the induction of cyclo-oxygenase-2 in cultured human airway smooth muscle cells. Br. J. Pharmacol. 121:579.[Medline]
B activation and interleukin 1ß gene expression in cultured human fibroblasts. J. Clin. Invest. 98:2042.[Medline]
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 H. El-Haroun, D. Bradbury, A. Clayton, and A. J. Knox Interleukin-1{beta}, Transforming Growth Factor-{beta}1, and Bradykinin Attenuate Cyclic AMP Production by Human Pulmonary Artery Smooth Muscle Cells in Response to Prostacyclin Analogues and Prostaglandin E2 by Cyclooxygenase-2 Induction and Downregulation of Adenylyl Cyclase Isoforms 1, 2, and 4 Circ. Res., February 20, 2004; 94(3): 353 - 361. [Abstract] [Full Text] [PDF]
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 M. Nie, L. Pang, H. Inoue, and A. J Knox Transcriptional Regulation of Cyclooxygenase 2 by Bradykinin and Interleukin-1{beta} in Human Airway Smooth Muscle Cells: Involvement of Different Promoter Elements, Transcription Factors, and Histone H4 Acetylation Mol. Cell. Biol., December 15, 2003; 23(24): 9233 - 9244. [Abstract] [Full Text] [PDF]
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Y. M. Zhu, D. A. Bradbury, L. Pang, and A. J. Knox Transcriptional Regulation of Interleukin (IL)-8 by Bradykinin in Human Airway Smooth Muscle Cells Involves Prostanoid-dependent Activation of AP-1 and Nuclear Factor (NF)-IL-6 and Prostanoid-independent Activation of NF-{kappa}B J. Biol. Chem., August 1, 2003; 278(31): 29366 - 29375. [Abstract] [Full Text] [PDF]
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S. Baraldo, D. S. Faffe, P. E. Moore, T. Whitehead, M. McKenna, E. S. Silverman, R. A. Panettieri Jr., and S. A. Shore Interleukin-9 influences chemokine release in airway smooth muscle: role of ERK Am J Physiol Lung Cell Mol Physiol, June 1, 2003; 284(6): L1093 - L1102. [Abstract] [Full Text] [PDF]
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A. Kumar, A. J. Knox, and A. M. Boriek CCAAT/Enhancer-binding Protein and Activator Protein-1 Transcription Factors Regulate the Expression of Interleukin-8 through the Mitogen-activated Protein Kinase Pathways in Response to Mechanical Stretch of Human Airway Smooth Muscle Cells J. Biol. Chem., May 23, 2003; 278(21): 18868 - 18876. [Abstract] [Full Text] [PDF]
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C.-D. Huang, O. Tliba, R. A. Panettieri Jr., and Y. Amrani Bradykinin Induces Interleukin-6 Production in Human Airway Smooth Muscle Cells: Modulation by Th2 Cytokines and Dexamethasone Am. J. Respir. Cell Mol. Biol., March 1, 2003; 28(3): 330 - 338. [Abstract] [Full Text] [PDF]
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