| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
But Not IL-1
mRNA in Human Epithelial Cells1
Division of Clinical Immunology, Department of Medicine, Johns Hopkins University School of Medicine, Asthma and Allergy Center, Baltimore, MD 21224
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
and IL-1
. dsRNA, which is
a common factor present during the life cycle of both DNA and RNA
viruses, is known to induce TNF- and IL-1 in a variety of cells.
In this work we provide data showing that dsRNA treatment induces
TNF- and IL-1 in human lung epithelial cells via two different
mechanisms. Our data show that dsRNA activation of dsRNA-activated
protein kinase (PKR) is associated with induction of TNF- but not
IL-1 expression. An inhibitor of PKR activation blocked the
dsRNA-induced elevations in TNF- but not IL-1 mRNA in epithelial
cells. Data obtained from infection of epithelial cells with a vaccinia
virus lacking the PKR inhibitory polypeptide, E3L, revealed that PKR
activation was essential for TNF- but not for IL-1 expression. In
this report, we provide experimental support for the differential
regulation of proinflammatory cytokine expression by dsRNA and viral
infections in human airway epithelial cells. |
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The epithelium is the primary target for respiratory viruses, and thus these cells are likely to play a pivotal role in viral-induced lung inflammation. In this regard, it is interesting to note that in vitro studies have demonstrated that viral infection of lung epithelial cells leads to the production of a variety of proinflammatory cytokines and chemokines (2, 3, 4, 5, 6, 7). However, the signaling pathways induced by viruses leading to cytokine production in human epithelial cells are not well understood.
TNF- and IL-1 both exert key regulatory functions with regard to
pathogenesis of many inflammatory diseases including bronchial
inflammation. They can up-regulate adhesion molecules, induce cell
activation, enhance cytotoxicity of macrophages and neutrophils, and
induce bronchial responsiveness (8, 9, 10, 11, 12). In addition,
severe lung pathologies are associated with inflammatory
cytokine-induced mucin secretion and lung fibrosis
(13, 14, 15, 16).
At high doses, TNF- causes tissue damage by inducing wasting
(cachexia) and ultimately death (17). Exposure of cultured
endothelial cells to TNF- resulted in the endothelin-1 secretion,
which is known to induce smooth muscle cell constriction, which leads
to airway narrowing (18). Interestingly, in a guinea pig
model, preincubation of naive tracheas with IL-1 and TNF- could
mimic -adrenoceptor dysfunction observed during Ag challenge
(19). This is significant because the -adrenoceptor is
a critical factor in the airway tone.
A rational hypothesis for respiratory virus-induced cytokine gene
expression in lung epithelial cells involves the presence of
dsRNA. dsRNA has been shown to induce several cytokines including
TNF- and IL-1 in monocytic cell lines (20, 21).
dsRNA is present as a virus genomic fragment, a replicative
intermediate, or a stem and loop structure in cells infected by most
viruses (22). Regardless of its source, dsRNA is a potent
activator of dsRNA-activated protein kinase
(PKR)3
(23, 24, 25). Activated PKR has been shown in several cell
types, including airway epithelial cells, to phosphorylate inhibitor of
NF-
B and thus activate NF-B (26, 27, 28, 29). Inasmuch as
NF-B is known to lead to the induction of several proinflammatory
genes (30), it is reasonable to hypothesize that this
pathway may lead to the expression of proinflammatory cytokines in
human airway epithelial cells.
In the present study, we address the hypothesis that the presence of
dsRNA in human epithelial cells leads to TNF- and IL-1
expression. Our data support our hypothesis that dsRNA-induced TNF-
gene expression is mediated via a PKR-dependent pathway, whereas
dsRNA-induced IL-1 mRNA expression occurs via a novel
PKR-independent pathway. This provides a molecular mechanism of
differential regulation of TNF- and IL-1 by dsRNA in human lung
epithelial cells.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The human epithelial cell line BEAS-2B was grown as a monolayer in RPMI 1640 supplemented with 5% FCS and 10 µg/ml gentamicin at 37°C in a 5% CO2 humidified chamber. The ssRNA poly(I), poly(C), and dsRNA poly(I:C) were purchased from Sigma-Aldrich (St. Louis, MO), were dissolved in PBS, and were used at concentrations indicated in each figure. Because we have observed significant differences in the capability of synthetic dsRNA poly(I:C) to activate PKR, we routinely test the fidelity of poly(I:C) by in vitro kinase assays detecting autophosphorylation of PKR.
The wild-type vaccinia and the mutant vaccinia virus lacking E3L polypeptide were a generous gift from Dr. B. L. Jacobs (Arizona State University, Tempe, AZ). BEAS-2B cells at 70% confluency were infected, at the multiplicity of infection (MOI) indicated in each figure, in RPMI 1640 supplemented with 2% FCS. After 1 h of incubation at 37°C, complete medium was added and the cells were allowed to incubate for 15 h before harvesting.
RNA extraction and RT-PCR
RNA was isolated using the TRIzol total RNA isolation reagent
(Life Technologies, Gaithersburg, MD). First-strand cDNA synthesis was
performed using superscript reverse transcriptase (Life Technologies).
The cDNA was then amplified in the presence of 2 µg/ml primers, 100
µM dNTPs, 0.25 U of Taq polymerase (AmpliTaq; PE Applied
Biosystems, Foster City, CA), 10 mM Tris-HCl (pH 9), 50 mM KCl, 1–2.5
mM MgCl2 (optimized for each primer set), and
0.001% gelatin in a final volume of 25 µl. The sequences of primers
used in the PCR were as follows: IL-1 forward,
5'-AAACAGATGAAGTGCTCCTTCAGG-3'; IL-1 reverse,
5'-TGGAGAACACCACTTGTTGCTCCA-3'; TNF- forward,
5'-CAGAGGGAAGAGTTCCCCAG-3'; TNF- reverse,
5'-CCTTGGTCTGGTAGGAGACG-3'; GAPDH forward,
5'-CACAGTCCATGCCATCACTG-3'; and GAPDH reverse,
5'-TACTCCTTGGAGGCCATGTG-3'. To collect the PCR products at the linear
range, the number of PCR cycles was optimized for each primer
set.
In vitro phosphorylation assays and ION
Reactions for in vitro trans-autophosphorylation were
performed as previously described (31). Briefly, cell
lysates were prepared from IFN--treated (100 U/ml) BEAS-2B
epithelial cells using a lysis buffer containing 20 mM HEPES (pH 7.5),
90 mM KCl, 5 mM magnesium acetate, and 1 mM DTT. Mixtures for in vitro
phosphorylation of detergent cellular extracts contained 20 mM HEPES
(pH 7.5), 90 mM KCl, 5 mM magnesium acetate, 1 mM DTT, 100 mM
[
-32P]ATP (sp. act., 1 Ci/mM; Amersham,
Arlington Heights, IL), 100 mM ATP (Sigma-Aldrich), and equal amounts
of detergent extract prepared from 1 x 106
cells, in a final volume of 25 µl. dsRNA was added to the reaction
mixtures at indicated concentrations followed by incubation at 30°C
for 15 min. The proteins were then subjected to electrophoresis through
10% SDS-PAGE and visualized by autoradiography.
The PKR inhibitor was designed to consist of a 20-mer (GGCC)5 RNA oligonucleotide and was synthesized by Dharmacon Research (Boulder, CO). The ssRNA was self-hybridized by heating to 80°C for 5 min and slow cooling to room temperature. The dsRNA oligonucleotide was then used in the experiments or was aliquoted and frozen at -80°C. To treat BEAS-2B cells, the inhibitor at a 25 and 50 µg/ml final concentration was mixed with 20 µl of Lipofectamine (Life Technologies) in a final volume of 500 µl OptiMEM (Life Technologies). After 2 h of treatment at 37°C, RPMI 1640 medium containing 10% FCS was added to the cells. After a 16-h incubation, cells were treated with poly(I:C) at 1 µg/ml and total cellular RNA was extracted.
Western blot analysis
After each treatment indicated in figures, BEAS-2B cells were washed once in PBS and an equal number of cells were lysed using 1x SDS-sample buffer containing 2.5% 2-ME. The proteins were denatured and reduced by heating the samples at 95°C for 5 min. The chromosomal DNA was then sheared by passing the samples through a 26-gauge needle. The proteins were resolved on a 12% SDS-PAGE and were electrotransferred onto nitrocellulose membranes. Polyclonal rabbit anti-vaccinia virus (Accurate Chemical, Westbury, NY), mAb to PKR (Santa Cruz Biotechnology, Santa Cruz, CA), or mAb to vaccinia E3L polypeptide (a generous gift from Dr. J. R. Bennink, National Institutes of Health, Bethesda, MD) were added at an optimal concentration, as determined by titration assays, and the blots were incubated for 1 h at room temperature. The immunoblotted proteins were visualized using HRP-conjugated anti-rabbit or anti-mouse IgG (Sigma-Aldrich) and the ECL Western blot detection system (Amersham).
Cloning and transient transfections of negative dominant mutant of PKR
The full-length cDNA for human PKR was isolated by RT-PCR of
total cellular RNA isolated from human T lymphocytes. For eukaryotic
expression, the cDNA was cloned into pSG-5 vector (Stratagene, La
Jolla, CA). For site-directed mutagenesis, we used specific primers
that amplified PKR lacking six amino acids (aa 361–366) in the
catalytic domain (
6PKR) according to Koromilas et al.
(32). The primer sequences to generate 6PKR were as
follows: forward, 5'-gcacttagtctttgaccttgaac-3'; and reverse,
5'-ttctgtgataaagggaccttgg-3'. The identity of the mutant was verified
by DNA sequencing.
For transient transfections, BEAS-2B cells were grown to 
60%
confluency on a 100-mm tissue culture plate. Ten micrograms of either
pSG-5 or pSG-6PKR was mixed with 25 µl of Lipofectamine (Life
Technologies) in a final volume of 500 µl OptiMEM (Life Technologies)
at room temperature. The mixture was allowed to incubated with the
cells for 4 h and then complete medium was added to the cells.
After 24 h, cells were divided and were allowed to adhere for an
additional 24 h. Cells were then treated with dsRNA at indicated
concentrations. Total cellular RNA was extracted after 2 h and was
subjected to RT-PCR.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
and IL-1 mRNA expression
Induction of inflammatory cytokines represents one of the early
events during the pathogenesis of respiratory viral infections. To test
for the induction of proinflammatory cytokines in epithelial cells,
primary human lung epithelial cells were isolated, treated with the
synthetic dsRNA poly(I:C) (1 µg/ml), and harvested at various times
after treatment. Total cellular RNA was extracted and semiquantitative
RT-PCR was performed using specific primers to the human TNF- and
IL-1. The data revealed that treatment of epithelial cells with
poly(I:C) resulted in a rapid time-dependent increase in TNF- and
IL-1 mRNA levels (Fig. 1
).
|
and IL-1 mRNA in BEAS-2B cells. In
both the primary epithelial and BEAS-2B cells, expression of TNF-
and IL-1 were detected as early as 30 min after dsRNA treatment. The
maximal levels were reached at 1–2 h after treatment. Whereas
TNF- mRNA levels returned to background level after 6 h,
IL-1 mRNA levels were sustained up to the 24-h time point (Fig. 1
B).
Because the synthetic dsRNA (poly(I:C)) is made up of two homopolymers
of inosinic and cytidylic acids, we determined whether each of these
polymers could induce proinflammatory cytokines. Treatment of the cells
with ssRNA (poly(I) or poly(C)) resulted in very little change in
TNF- and IL-1 expression; however, after hybridization, poly(I:C)
could efficiently induce the expression of both cytokines (Fig. 1C). These data suggest that the presence of RNA with
double-stranded structures is required for the induction of
proinflammatory cytokines in human epithelial cells. Furthermore, the
data showed that the expression of inflammatory cytokines was not due
to LPS contamination in the RNA preparation, which is a potent inducer
of proinflammatory cytokines (33).
To determine the optimal dsRNA concentration, BEAS-2B cells were
treated with increasing concentrations of dsRNA and the cells were
harvested at 2 h posttreatment. RT-PCRs were performed and the
results revealed that dsRNA induction of TNF- reproducibly followed
a bell-shaped curve (Fig. 1, D and E). This
biphasic induction is consistent with the dsRNA activation curve of PKR
in BEAS-2B (Fig. 2A) and other
cells (23, 24, 25). In contrast, dsRNA induction of IL-1
did not follow a similar bell-shaped curve, suggesting that expression
of these cytokines may follow different signaling pathways.
|
but not IL-1
expression
The induction of proinflammatory cytokines by dsRNA has been
demonstrated in a variety of cells (20, 34, 35, 36, 37, 38). Also, PKR
is ubiquitously expressed in many cell types, but the presence of PKR
in human lung bronchial epithelial cells has not been well
studied.Therefore, to further study the role of PKR in the induction of
proinflammatory cytokines in human epithelial cells, we performed in
vitro kinase assays detecting PKR trans-autophosphorylation.
Cell extracts were subjected to in vitro kinase reactions in the
presence of increasing concentrations of dsRNA (Fig. 2A).
The data, which are in agreement with previous reports, showed that PKR
is present in an inactive form and, to be activated, it requires
interaction with low concentrations (0.001–1 µg/ml) of dsRNA (the
identity of PKR was determined by Western blot analysis; data not
shown). As previously reported in other cell types and as indicated in
Fig. 2A, high concentrations of dsRNA (>10 µg/ml) are not
as effective in PKR activation (23, 24, 25). The lack of PKR
activation at high dsRNA concentrations is due to monomeric binding of
PKR to dsRNA and hence no trans-autophosphorylation
(39, 40, 41).
To determine the role of PKR in TNF- and IL-1 expression we
synthesized a competitive inhibitor of PKR activation. Short dsRNA
molecules (<30 bp) are known to bind but selectively inhibit PKR
activity (42, 43); therefore, a 20-mer oligonucleotide was
designed to bind to PKR in a monomeric fashion and block PKR
trans-autophosphorylation. To verify inhibition of PKR by
this inhibitory oligonucleotide (ION), we performed in vitro kinase
assays in the presence of 1 µg/ml dsRNA. The data showed that ION
blocked the dsRNA activation of PKR in a concentration-dependent manor
(Fig. 2B). At 100 µg/ml, ION virtually abolished
dsRNA-induced PKR activation (Fig. 2B). We then tested the
effect of ION on proinflammatory cytokine expression. BEAS-2B cells
were treated with 25 or 50 µg/ml of the inhibitor before treatment
with 1 µg/ml poly(I:C). After 2 h, total cellular RNA was
prepared and the data from RT-PCR experiments revealed that the
presence of ION significantly reduced the level of TNF- but had
little effect on IL-1 mRNA expression (Fig. 2C).
To more definitively characterize the role of PKR in proinflammatory
cytokine expression, BEAS-2B cells were transiently transfected with a
plasmid carrying a negative dominant mutant of PKR (pSG-6PKR), and
as a control the cells were transfected with the vector alone (pSG-5).
After 24 h cells were removed and aliquoted into several dishes.
The transfected cells were then allowed to adhere and incubate for an
additional 24 h. The cells were left untreated or were treated
with poly(I:C) at 0.3 µg/ml or 1 µg/ml. After 2 h, total
cellular RNA was extracted and subjected to RT-PCR. First, the presence
of PKR in the cells transfected with pSG-6PKR was determined by
Western blot analysis of cellular proteins using a PKR-specific mAb
(Fig. 3A). The data from
RT-PCR showed a significant decrease in the level of dsRNA induction of
TNF- but not IL-1 mRNA in the cells that were transfected with
the pSG-6PKR as compared with the control plasmid (Fig. 3B). These data are consistent with our hypothesis that
dsRNA induction of proinflammatory cytokines follows different
signaling pathways.
|
but not IL-1
expressionAlthough the antiviral effects of PKR are well studied, viruses can escape this putative host defense mechanism. Several viruses including reovirus, influenza virus, adenovirus, and vaccinia virus have been described to possess such inhibitors (31, 42, 44, 45). Vaccinia virus-associated PKR inhibitory activity is achieved by stoichiometric interaction of E3L polypeptide with dsRNA, thus sequestering the dsRNA from PKR. Deletion of E3L results in a mutant vaccinia virus that, upon infection of eukaryotic cells, can activate PKR (29, 46, 47).
Taking advantage of the vaccinia system, we examined the role of virus
activation of PKR in TNF- and IL-1 expression. We infected
BEAS-2B cells with wild-type vaccinia virus or the E3L-deleted mutant
at MOI indicated in the figures. After 15 h, both protein and
total cellular RNA were harvested. We first verified the viral
infection of BEAS-2B cells with vaccinia virus (wild-type and
E3L-deleted) by Western blot analysis. The presence of viral proteins
in the infected cells was examined using a polyclonal anti-vaccinia
virus Ab (Fig. 1A). Next, the presence of E3L polypeptide in
the infected cells was confirmed by Western blot analysis using a
specific anti-E3L mAb (Fig. 4B). As indicated in Fig. 4A, vaccinia virus can infect BEAS-2B cells; however, the
level of protein synthesis is lower in cells infected with E3L-deleted
mutant. This is expected because this mutant can activate PKR and
activated PKR is known to down-regulate protein synthesis
(46). The activation of PKR in vaccinia virus-infected
cells was examined by in vitro kinase assays (Fig. 4C). The
data revealed that, in extracts prepared form wild-type vaccinia
virus-infected cells, PKR could not be activated in the presence of
exogenous dsRNA. In contrast, in extracts prepared from
E3L-deleted vaccinia virus-infected cells, PKR was activated in the
absence of exogenous dsRNA. These data suggest that expression of E3L
polypeptide in the infected cells can regulate dsRNA activation of
PKR.
|
mRNA. In contrast, TNF- was only induced
when the cells were infected with the E3L-deleted mutant (Fig. 4D). These data, which support our hypothesis, suggest that
induction of IL-1 is PKR independent and that viral induction of
TNF- requires PKR activation. |
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
In this study, we demonstrate that dsRNA is an effective inducer of two
important proinflammatory cytokines, TNF- and IL-1, in human
bronchial epithelial cells. Interestingly, the data support the
hypothesis that dsRNA induces expression of TNF- mRNA by a signaling
mechanism different from that involved in the induction of IL-1. One
of the key signaling steps for dsRNA induction of TNF- expression is
trans-autophosphorylation and activation of PKR. This
contention is supported by our observations. First, our data showed a
similar bell-shaped concentration-response relationship between
dsRNA-induced PKR activation and TNF- expression. Similar to other
reports, low concentrations of dsRNA (0.01–10 µg/ml) effectively
activate PKR, but at higher concentrations (>10 µg/ml) dsRNA is much
less effective (23, 24, 25). In our in vitro assays, indeed,
30 µg/ml dsRNA had very little effect on PKR activation (Fig. 2). It
is known that PKR dimerization is required for activation, and these
dimers are formed when bound to the optimal concentrations of dsRNA. At
large concentrations of dsRNA, monomeric binding of PKR occurs and
hence no activation (39, 40, 41, 53).
Although these experiments provided suggestive evidence for a role for
PKR in dsRNA-induced TNF- expression, a selective inhibitor was
needed to more directly address this hypothesis. Oligonucleotides below
30-bp dsRNA are known to bind to PKR in a monomeric fashion and,
therefore, act as a specific competitive inhibitor of PKR activation
(43, 54, 55, 56). Accordingly, to inhibit PKR activation, we
designed an ION consisting of (GGCC)5 dsRNA
oligomers. We found that the presence of ION effectively inhibited
dsRNA-induced PKR activation. At relevant concentrations, pretreatment
of BEAS-2B cells with ION also significantly blocked the dsRNA-induced
TNF- expression. Considered with the concentration response analysis
discussed above, these data support a role for PKR in the induction of
TNF- gene expression by dsRNA.
To more definitively examine our hypothesis, we used a negative
dominant mutant of PKR. Our data from the transient transfection
studies revealed that the presence of this mutant significantly blocked
the expression of TNF- but did not have a significant effect on
IL-1 expression. Finally, we took advantage of a recombinant
vaccinia virus system in which the PKR inhibitory polypeptide (E3L) was
deleted. In these experiments, the wild-type vaccinia virus, which does
not activate PKR, did not induce TNF- but induced IL-1
efficiently. However, the E3L-deleted vaccinia virus, which is known to
activate PKR, induced both TNF- and IL-1 (Fig. 4) (29, 46, 47).
Collectively, based on our data, we favor the hypothesis that dsRNA
activation of PKR leads to induction of TNF-. However, the
possibility exists that inhibition of PKR may result in the release of
a specific inhibitor of TNF- expression. The exact mechanisms by
which dsRNA and viral infections can lead to IL-1 expression
independent of PKR are currently being investigated. It is interesting
to note that a report by Osman et al. (57) showed that PKR
activation may be necessary for splicing of precursor TNF- RNA into
mature transcripts. At this point we have not examined the effect of
dsRNA on TNF- RNA splicing in human lung epithelial cells. The
Toll-like receptor 3 was recently reported to recognize dsRNA and
activate NF-B in murine macrophages, but the relevance of this
receptor in our observations is not yet understood
(58).
In addition to the beneficial proinflammatory and immunoregulatory
activities of TNF- and IL-1, the presence of these cytokines may
also be deleterious to the host during viral infections. The wasting
associated with HIV-infected individuals is due to chronic presence of
TNF- (59, 60). Also, the morbidity and mortality of
asthma are commonly associated with viral induction of proinflammatory
cytokines such as TNF-, IL-1, IL-6, IL-8, GM-CSF, and RANTES
(7, 13, 61, 62, 63, 64, 65). Considered together, our data support
divergent signaling mechanisms leading to the expression of cytokines
with similar proinflammatory effects. This can enhance the ability of
the host to mount an effective immune response toward viruses that have
evolved to subvert any single pathway. These findings may provide a
strategy aimed at selective and specific down-regulation of
viral-induced TNF- or IL- production.
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Farhad Imani, Division of Clinical Immunology, Department of Medicine, Johns Hopkins University School of Medicine, Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224. E-mail address: fimani{at}mail.jhmi.edu
3 Abbreviations used in this paper: PKR, dsRNA-activated protein kinase; MOI, multiplicity of infection; ION, inhibitory oligonucleotide.
Received for publication January 23, 2002. Accepted for publication April 16, 2002.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
by lower airway epithelial cells and eosinophils infected with respiratory syncytial virus. J. Virol. 72:4756. in asthma. Clin. Exp. Allergy 23:247.[Medline]
on expression of ICAM-1 in human airway epithelial cells in vitro: signaling pathways controlling surface and gene expression. Am. J. Respir. Cell Mol. Biol. 22:685. to rat lung induces severe pulmonary inflammation and patchy interstitial fibrogenesis with induction of transforming growth factor-1 and myofibroblasts. Am. J. Pathol. 153:825. (TNF-) gene expression in parainfluenza type 1 (Sendai) virus-induced bronchiolar fibrosis. Am. J. Pathol. 152:513.[Abstract]
. Eur. J. Pharmacol. 284:221.[Medline]
stimulates mucin secretion and cyclic GMP production by guinea pig tracheal epithelial cells in vitro. Am. J. Respir. Cell Mol. Biol. 20:413.. Am. J. Physiol. 262:C854.-adrenoceptor-mediated relaxation in tracheas of a guinea pig antigen model. Am. J. Respir. Cell Mol. Biol. 8:153.
gene regulation by virus and lipopolysaccharide. Proc. Natl. Acad. Sci. USA 87:9769.B activation by double-stranded-RNA-activated protein kinase (PKR) is mediated through NF-B-inducing kinase and IB kinase. Mol. Cell. Biol. 20:1278.B by phosphorylating IB. Proc. Natl. Acad. Sci. USA 91:6288.B-NF-B structures: at the interface of inflammation control. Cell 95:729.[Medline]
3 protein. Proc. Natl. Acad. Sci. USA 85:7887. gene. J. Biol. Chem. 270:25426.B and IFN-regulatory factor transcription factors. J. Immunol. 164:5352. kinase. Cell 45:195.[Medline]
mRNA renders splicing dependent on the activation of protein kinase PKR. Genes Dev. 13:3280.B by Toll-like receptor 3. Nature 413:732.[Medline]
from AIDS sera. AIDS Res. Hum. Retroviruses 7:545.[Medline]
. Am. J. Physiol. 273:L749.-interferon in lower respiratory tract infections of children. Pediatr. Infect. Dis. J. 15:883.[Medline]
/, MxA, 2',5'-oligoadenylate synthetase, and HLA gene expression in influenza A-infected human lung epithelial cells. J. Immunol. 158:2363.[Abstract]This article has been cited by other articles:
|
|
 |
|
  C. Myskiw, J. Arsenio, R. van Bruggen, Y. Deschambault, and J. Cao Vaccinia Virus E3 Suppresses Expression of Diverse Cytokines through Inhibition of the PKR, NF-{kappa}B, and IRF3 Pathways J. Virol., July 1, 2009; 83(13): 6757 - 6768. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Chakrabarti, A. J. Sadler, N. Kar, H. A. Young, R. H. Silverman, and B. R. G. Williams Protein Kinase R-dependent Regulation of Interleukin-10 in Response to Double-stranded RNA J. Biol. Chem., September 12, 2008; 283(37): 25132 - 25139. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. V. Limmon, M. Arredouani, K. L. McCann, R. A. C. Minor, L. Kobzik, and F. Imani Scavenger receptor class-A is a novel cell surface receptor for double-stranded RNA FASEB J, January 1, 2008; 22(1): 159 - 167. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. C. L. Spurrell, S. Wiehler, R. S. Zaheer, S. P. Sanders, and D. Proud Human airway epithelial cells produce IP-10 (CXCL10) in vitro and in vivo upon rhinovirus infection Am J Physiol Lung Cell Mol Physiol, July 1, 2005; 289(1): L85 - L95. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Vijay-Kumar, J. R. Gentsch, W. J. Kaiser, N. Borregaard, M. K. Offermann, A. S. Neish, and A. T. Gewirtz Protein Kinase R Mediates Intestinal Epithelial Gene Remodeling in Response to Double-Stranded RNA and Live Rotavirus J. Immunol., May 15, 2005; 174(10): 6322 - 6331. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Homma, A. Kato, N. Hashimoto, J. Batchelor, M. Yoshikawa, S. Imai, H. Wakiguchi, H. Saito, and K. Matsumoto Corticosteroid and Cytokines Synergistically Enhance Toll-Like Receptor 2 Expression in Respiratory Epithelial Cells Am. J. Respir. Cell Mol. Biol., October 1, 2004; 31(4): 463 - 469. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Proud, S. P. Sanders, and S. Wiehler Human Rhinovirus Infection Induces Airway Epithelial Cell Production of Human {beta}-Defensin 2 Both In Vitro and In Vivo J. Immunol., April 1, 2004; 172(7): 4637 - 4645. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. R. Meusel and F. Imani Viral Induction of Inflammatory Cytokines in Human Epithelial Cells Follows a p38 Mitogen-Activated Protein Kinase-Dependent but NF-{kappa}B-Independent Pathway J. Immunol., October 1, 2003; 171(7): 3768 - 3774. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H.-R. Zhou, A. S. Lau, and J. J. Pestka Role of Double-Stranded RNA-Activated Protein Kinase R (PKR) in Deoxynivalenol-Induced Ribotoxic Stress Response Toxicol. Sci., August 1, 2003; 74(2): 335 - 344. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
