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-Melanocyte-Stimulating Hormone Inhibits the Nuclear Transcription Factor NF-
B Activation Induced by Various Inflammatory Agents
Cytokine Research Laboratory, Department of Molecular Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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-Melanocyte-stimulating hormone (-MSH) is a
tridecapeptide found mainly in the brain, pituitary, and circulation.
It inhibits most forms of inflammation by a mechanism that is not
known. As most types of inflammation require activation of NF-
B, we
investigated the effect of -MSH on the activation of this
transcription factor by a wide variety of inflammatory stimuli.
Electrophoretic mobility shift assay showed that -MSH completely
abolished TNF-mediated NF-B activation in a dose- and time-dependent
manner. It also suppressed NF-B activation induced by LPS, okadaic
acid, and ceramide. The effect was specific, as the activation of the
transcription factor activating protein-1 by TNF was unaffected.
Western blot analysis revealed that TNF-dependent degradation of the
inhibitory subunit of NF-B, IB, and nuclear translocation of
the p65 subunit of NF-B were also inhibited. This correlated with
suppression of NF-B-dependent reporter gene expression induced by
TNF. The inhibitory effect of -MSH appeared to be mediated through
generation of cAMP, as inhibitors of adenylate cyclase and of protein
kinase A reversed its inhibitory effect. Similarly, addition of
membrane-permeable dibutyryl cAMP, like -MSH, suppressed TNF-induced
NF-B activation. Overall, our results suggest that -MSH
suppresses NF-B activated by various inflammatory agents and that
this mechanism probably contributes to its anti-inflammatory
effects. |
Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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One molecule effecting a link between the two systems is
-melanocyte-stimulating hormone
(-MSH),2 a tridecapeptide
derived from pro-opiomelanocortin and found in pituitary, brain, skin,
and circulation (7). It has been found to interact with various cells
of the immune system and down-regulate either the production or the
action of the proinflammatory cytokines IL-1, TNF-, and IL-6
(8, 9, 10, 11), and thus acts as an anti-inflammatory agent. Receptors for
-MSH have been detected on both monocyte/macrophages and neutrophils
(9, 10). The production of nitric oxide involved in inflammation is
also regulated by -MSH (9). At the molecular level, how -MSH
regulates inflammation induced by different stimuli is not
understood.
One possible link is through another mediator of the immune
response, TNF, and a transcription factor it activates, NF-B. TNF is
a cytokine primarily produced by macrophages that regulates cellular
growth, septic shock, inflammation, and type I human immunodeficiency
viral replication (12). How TNF regulates this wide variety of
functions is not known, but activation of a nuclear transcription
factor, NF-B, appears to play a major role in all these processes.
In its inactive state, NF-B exists as a heterotrimeric complex in
the cytoplasm consisting of p50, p65, and IB (13). Within minutes
of activation by inflammatory agents such as TNF, IB undergoes
phosphorylation, ubiquitination, and proteolytic degradation, thus
unmasking the nuclear localization signal on p65 and allowing
translocation of the p50-p65 complex to the nucleus. NF-B is a
ubiquitous transcription factor, and it plays a critical role in the
immune system by controlling the expression of various inflammatory
cytokines, MHC genes, the nitric oxide synthase gene, and other genes
involved in inflammation. The inappropriate regulation of NF-B and
its dependent genes have been associated with various pathologic
conditions, including septic shock, graft-vs-host reaction, acute
inflammatory conditions, acute phase response, viral replication,
radiation damage, atherosclerosis, and cancer.
The aim of the present study was to determine whether the
anti-inflammatory properties assigned to -MSH are due to its
ability to down-regulate the activation of NF-B by a variety of
inflammatory stimuli in cells of the immune system. Our results
demonstrate that -MSH is a potent inhibitor of the activation of
NF-B by TNF and other agents. It also blocked NF-B-dependent gene
transcription. This suppression of NF-B activation by -MSH was
found to be dependent on cAMP. Thus, -MSH is a potential candidate
for modulation of NF-B-dependent pathologic conditions.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Penicillin, streptomycin, RPMI 1640 medium, and FCS were
obtained from Life Technologies (Grand Island, NY). -MSH, glycine,
NaCl, H-7, and BSA were obtained from Sigma (St. Louis, MO). Adenosine
cyclic 3',5'-phosphorothiolate triethylammonium salt (Rp-cAMPS) and H-8
((methylamino)ethyl-5-isoquinolinesulfonamide, HCl) were obtained from
Calbiochem (San Diego, CA). H-8 was dissolved in water at a
concentration of 2 mM and kept at -20°C. Dideoxyadenosine and
dibutyryl cAMP were obtained from LC Laboratory (San Diego, CA).
Bacteria-derived recombinant human TNF, purified to homogeneity with a
sp. act. of 5 x 107 U/mg was provided by Genentech
(South San Francisco, CA). Abs against IB, p65, p50, cyclin D1,
and c-Rel, and double-stranded oligonucleotide with AP-1 consensus
sequence were obtained from Santa Cruz Biotechnology (Santa Cruz, CA).
NF-B oligonucleotides from the HIV long terminal repeat,
5'-TTGTTACAAGGGACTTTCCGCTGGGGACTTTCCAGGGAGGCGTGG-3'
(14), and a double-stranded mutated oligonucleotide,
5'-TTGTTACAACTCACTTTCCGCTGCTCACTTTCCAGGGAGGCGTGG-3',
were synthesized and supplied by Life Technologies (Grand Island, NY).
(Underlined regions represent a concensus NF-B binding sequence.)
The rat plasmids -243RMICAT (wild) and -243RMICAT-m (mutant),
containing the chloramphenicol acetyltransferase (CAT) gene with either
the wild-type or mutated NF-B binding site were supplied by Dr. M.
Tien Kuo of the M. D. Anderson Cancer Center (Houston, TX). The
characterization of these plasmids has been described previously in
detail (15). The well-characterized human histiocytic lymphoma U-937
cell line (16) was obtained from American Type Cell Culture Collection
(Manassas, VA) and used in mycoplasma-free cultures.
Electrophoretic mobility shift assays (EMSAs)
Cells (2 x 106/ml) were treated separately with different concentrations of TNF at 37°C. Nuclear extracts were then prepared according to the method of Schreiber et al. (17). Briefly, 2 x 106 cells were washed with cold PBS and suspended in 0.4 ml of lysis buffer (10 mM HEPES (pH 7.9), 10 mM KCl, 0.1 mM EDTA, 0.1 mM EGTA, 1 mM DTT, 0.5 mM PMSF, 2 µg/ml leupeptin, 2 µg/ml aprotinin, and 0.5 mg/ml benzamidine). The cells were allowed to swell on ice for 15 min, after which 12.5 µl of 10% Nonidet P-40 was added. The tube was then vigorously mixed on a vortex machine for 10 s, and the homogenate was centrifuged for 30 s in a microfuge. The nuclear pellet was resuspended in 25 µl of ice-cold nuclear extraction buffer (20 mM HEPES (pH 7.9), 0.4 M NaCl, 1 mM EDTA, 1 mM EGTA, 1 mM DTT, 1 mM PMSF, 2.0 µg/ml leupeptin, 2.0 µg/ml aprotinin, and 0.5 mg/ml benzamidine), and the tube was incubated on ice for 30 min with intermittent mixing. The tube was then centrifuged for 5 min in a microfuge at 4°C, and the supernatant (nuclear extract) was either used immediately or stored at -70°C for later use. The protein content was measured by the method of Bradford (18).
EMSAs were performed by incubating 4 µg of nuclear extract with 16
fmol of 32P end-labeled 45-mer double-stranded NF-B
oligonucleotide from the HIV long terminal repeat,
5'-TTGTTACAAGGGACTTTCCGCTGGGGACTTTCCAGGGAGGCGTGG-3'
(14), for 15 min at 37°C (the NF-B binding sites are underlined).
The incubation mixture included 2–3 µg of poly (dI-dC) in a binding
buffer (25 mM HEPES pH 7.9, 0.5 mM EDTA, 0.5 mM DTT, 1% Nonidet P-40,
5% glycerol, and 50 mM NaCl) (19, 20). The DNA-protein complex formed
was separated from free oligonucleotide on 6.6% native polyacrylamide
gel using buffer containing 50 mM Tris, 200 mM glycine pH 8.5, and 1 mM
EDTA (21), and then the gel was dried. A double-stranded mutated
oligonucleotide,
5'TTGTTACAACTCACTTTCCGCTGCTCACTTTCCAGGGAGGCGTGG-3',
was used to examine the specificity of binding of NF-B to the DNA.
The specificity of binding was also examined by competition with the
unlabeled oligonucleotide.
The EMSAs for AP-1 were performed as described for NF-B using
32P end-labeled double-stranded oligonucleotides. The
specificity of binding was determined routinely by using an excess of
unlabeled oligonucleotide for competition as described previously (22).
Visualization and quantitation of radioactive bands were conducted with a PhosphorImager (Molecular Dynamics, Sunnyvale, CA) using ImageQuant software.
Western blotting for IB, p50, and p65
After the NF-B activation reaction described above,
postnuclear extracts were resolved on 10% SDS-polyacrylamide gels for
IB. To determine the p50 and p65 levels, nuclear and postnuclear
(cytoplasmic) extracts were resolved on 8% SDS-PAGE. The proteins were
electrotransferred from the gels to nitrocellulose filters; probed with
rabbit polyclonal Abs against IB, p50, and p65; and then detected
by chemiluminescence (ECL, Amersham, Arlington Heights, IL) (23). The
bands obtained were quantitated on a Personal Densitometer Scan version
1.30 using ImageQuant software version 3.3 (Molecular Dynamics).
Transient transfection and CAT assay
U-937 cells were transiently transfected with -243RMICAT (wild)
and -243RMICAT-m (mutant) genes for 6 h using the calcium
phosphate method, according to the instructions supplied by the
manufacturer (Life Technologies). After transfection, the cells were
incubated for 24 h at 37°C, treated with -MSH (50 nM) for
24 h, stimulated with 100 pM TNF for 1 h, then washed with
PBS and examined for CAT activity as previously described (24).
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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-MSH on the activation of
transcription factor NF-B. We used human monocytic U937 cells for
these studies because their response to NF-B activation by various
stimuli has been well characterized in our laboratory (22, 25). These
cells were treated with up to 100 nM -MSH for 24 h and then
examined for cell viability by the trypan blue dye exclusion method. A
viability of 94.6% was noted in 100 nM -MSH-treated cells compared
with 97.8% in untreated cells. Thus, the time of incubation and the
concentration of hormone used in our studies had no significant effect
on cell viability.
-MSH inhibits TNF-dependent NF-B activation
U-937 cells were preincubated for 24 h with different
concentrations of -MSH and then treated with TNF (100 pM) for 30 min
at 37°C. They were then examined for NF-B activation by EMSA. The
results shown in Figure 1
A
indicate that 25 to 50 nM hormone inhibited most of the TNF response.
-MSH by itself did not activate NF-B. We next tested the kinetics
of inhibition. Cells were exposed to -MSH for 0 to 24 h and
then activated by TNF for 30 min. TNF-mediated NF-B activation was
inhibited maximally when the cells were pretreated for 24 h with
the hormone (Fig. 1B).
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B within 5 min and that
this induction is more intense than that obtained with cells using
100-fold lower concentrations for longer times (25). To determine the
effect of -MSH on NF-B activation, both untreated and
hormone-pretreated cells were incubated with various concentrations of
TNF (0–10,000 pM) for 30 min, and then NF-B was assayed by EMSA
(Fig. 1
C). Although the activation of NF-B by 10,000 pM
TNF was strong, -MSH completely inhibited it, just as it did at 100
pM TNF. These results show that -MSH is a very potent inhibitor of
NF-B activation.
To determine the effect of -MSH on the kinetics of NF-B
activation, both untreated and hormone-pretreated cells were incubated
with TNF (100 pM) for different times, and then EMSA was conducted. The
activation of NF-B by TNF was detected with the increased time of
incubation in control cells, whereas in -MSH-pretreated cells, no
activation of NF-B was detected even after up to 60 min of TNF
stimulation (Fig. 1D).
NF-B inhibited by -MSH consists of p50 and p65 subunits
Various combinations of Rel/NF-B proteins can constitute an
active NF-B heterodimer that binds to specific DNA sequences. To
show that the retarded band visualized by EMSA in TNF-treated cells was
indeed NF-B, we incubated nuclear extracts from TNF-activated cells
with Ab to either p50 (NF-BI) or p65 (Rel A) subunits, or both, and
then conducted EMSA. Abs to either subunit of NF-B decreased the
migration of the band on the gel (Fig. 2A), thus suggesting that the
TNF-activated complex consisted of p50 and p65 subunits. Both Abs
together induced the migration of all the activated NF-B bands to a
high m.w. complex. Neither preimmune serum nor the irrelevant Abs,
anti-c-Rel or anti-cyclin DI, had any effect on the mobility of
NF-B. Competition with excess unlabeled NF-B probe (100-fold)
produced complete disappearance of the band, indicating the specificity
of NF-B.
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-MSH does not inhibit TNF-induced AP-1 activation
Whether -MSH specially blocks the activation of NF-B or also
affects activation of other transcription factors such as AP-1 (26) was
investigated. The cells were treated with different concentrations of
the hormone, then treated with TNF (1 nM for 1 h) for AP-1
activation; the nuclear extracts were prepared, incubated with the
labeled AP-1 probe, and subjected to EMSA. Figure 2B shows
that -MSH had no effect on the activation of AP-1 transcription
factors. Thus, -MSH specially blocks the activation of NF-B.
-MSH blocks LPS-, okadaic acid-, and ceramide-mediated
activation of NF-B
Besides TNF, NF-B activation is also induced by several other
inflammatory stimuli, including phorbol ester, hydrogen peroxide, LPS,
okadaic acid, and ceramide. The signal transduction pathway leading to
NF-B activation induced by these agents may differ. We therefore
examined the effect of -MSH on the activation of the transcription
factor by these agents. The results shown in Figure 3 indicate that the hormone completely
blocked the activation of NF-B induced by all these agents except
PMA and H2O2, whose activities were partially
inhibited. The partial inhibition observed in some cases could be
because the time and dose of -MSH used were those optimized for TNF.
Alternatively, PMA and H2O2 may activate
NF-B by a different mechanism. These results also suggest that
-MSH may act at a step where LPS, okadaic acid, and ceramide
converge in the signal transduction pathway leading to NF-B
activation.
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B activation by -MSH is not cell type
specific
Besides myeloid cells, we also examined the ability of -MSH to
block TNF-induced NF-B activation in epithelial (HeLa), glioma (H4),
and lymphoid (Jurkat) cells. The results of these experiments (Fig. 4) indicate that -MSH inhibited
NF-B in all three cell types. Almost complete inhibition was
observed with epithelial and glioma cells, and partial inhibition was
observed with Jurkat cells, thus suggesting that this effect of -MSH
is not cell type specific. The NF-B binding in all cells was
abrogated by a 25-fold molar excess of unlabeled oligonucleotide.
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-MSH inhibits TNF-dependent degradation of IB and nuclear
translocation of the p65 subunit of NF-B
The translocation of NF-B to the nucleus is preceded by the
phosphorylation and proteolytic degradation of IB (27). To
determine whether the inhibitory action of -MSH was due to its
effect on IB degradation, the cytoplasmic levels of IB
proteins was examined by Western blot analysis. Treatment of cells for
24 h with -MSH alone had no effect on the synthesis of IB
(Fig. 5A). The IB band,
however, was decreased in intensity within 5 min of TNF treatment of
cells and then disappeared within 10 min. The band reappeared by 30
min. When the hormone was present, the band did not diminish,
indicating that -MSH blocked the TNF-mediated degradation of
IB (Fig. 5A).
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B activation also requires nuclear translocation of the
p65 subunit of NF-B, we measured the levels of p65 in the cytoplasm
and nucleus. As expected upon TNF treatment, the level of p65 declined
in the cytoplasm and concurrently increased in the nucleus (Fig. 5B). Treatment of cells with -MSH abolished the
TNF-dependent change in the nuclear and cytoplasmic p65 levels. These
results show that -MSH inhibited the TNF-induced translocation of
p65 to the nucleus, which is consistent with the inhibition of
TNF-dependent degradation of IB. Besides p65, the effect of the
hormone on the cytoplasmic and nuclear pools of the other member of the
Rel family of proteins was also examined. The results shown in Figure 5C indicate that neither TNF by itself nor its combination
with -MSH had any effect on the p50 level. An equal level of p50
protein noted in Figure 5C also indicates that equal amounts
of protein were loaded for the results shown in A,
B, and C.
-MSH represses reporter-NF-B-CAT gene expression
The MDR promoter containing the NF-B binding site linked
to the CAT gene was used to examine gene expression after stimulation
by TNF. We used a transient expression assay to determine the effect of
-MSH on the TNF-induced MDR gene linked to the CAT gene. Almost a
threefold increase in CAT activity was noted upon stimulation with TNF
(Fig. 6), but this was reduced by almost
90% when the wild-type gene-transfected cells were pretreated with the
hormone for 24 h before TNF treatment. As a control, transfection
with the reporter gene containing the mutated NF-B binding site did
not result in induction of CAT by TNF. These results demonstrate that
-MSH represses NF-B-dependent reporter gene expression induced by
TNF.
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-MSH-mediated inhibition of NF-B activation is mediated
through cAMP
It has been reported that -MSH transduces its signal through
cAMP. To examine the role of cAMP, we used dideoxyadenosine (ddAdo), a
potent inhibitor of adenylate cyclase (28), the enzyme responsible for
the generation of cAMP. Cells were exposed to different concentrations
of ddAdo for 2 h and then to -MSH for 24 h, and then were
stimulated with TNF (100 pM) for 30 min. The results shown in Figure 7A show that ddAdo did not
interfere with TNF-induced NF-B activation, but it protected against
-MSH-mediated suppression of NF-B stimulated by TNF. Treatment of
cells with exogenous cAMP (dibutyryl cAMP) mimicked -MSH, in that it
induced a gradual decrease in TNF-induced NF-B activation with
increases in its concentration (Fig. 7B).
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-MSH-induced inhibition of NF-B activation. For this, cells were
pre-exposed to either Rp-cAMPS isomer (100 µM) or 2 µM H-8 for
1 h at 37°C and then treated with -MSH for 24 h, were
exposed simultaneously to Rp-cAMPS isomer or to 2 µM H-8 and -MSH
for 24 h, or were treated after the hormone exposure and then
examined for TNF-induced NF-B activation. Pretreatment with
both PKA inhibitors blocked the inhibitory effects of -MSH, while
coincubation with the hormone was partially effective. After treatment
with Rp-cAMPS isomer or of H-8 there was almost no protection of
-MSH-mediated inhibition of NF-B activation (Fig. 7, C
and D). These results indicate that the effects of -MSH
are mediated through activation of PKA. In contrast to PKA inhibitor,
the PKC inhibitor H7 had no effect on -MSH-mediated inhibition of
NF-B activation (Fig. 7E), suggesting that the effect of
the PKA inhibitor is specific. |
Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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-MSH, have anti-inflammatory effects, the mechanism is not
understood. In this study we found that -MSH specifically
down-regulates a transcription factor, NF-B, whose activation is
induced by a wide variety of inflammatory stimuli, including TNF,
endotoxin, ceramide, and okadaic acid. This suppression of NF-B
activation by -MSH was found not to be cell type specific and
was mediated through generation of cAMP and activation of PKA.
-MSH is primarily produced by the cells in the brain and pituitary.
It stimulates melanocytes and other cell types. This hormone interacts
with different cells through five distinct G protein-coupled
receptors (MC-1 to MC-5) (30, 31). All except the MC-2 receptor have
been found in brain tissue; the MC-2 receptor was found only in the
adrenal cortex. Recently, it was reported that both human and murine
macrophage cell lines and human neutrophils express MC-1 receptor (8, 9). Thus, it is highly likely that the effects of -MSH described
here in the human monocytic cell line U-937 and others are mediated
through activation of the MC-1 receptor. Like other G protein-coupled
receptors, it has also been shown that -MSH mediates its effects in
neutrophils and other cell types through an increase in intracellular
cAMP. In our studies, we found that inhibitors of adenylate cyclase
blocked the suppressive effect of -MSH, suggesting a critical role
of cAMP in inhibition of NF-B activation. In addition, treatment of
cells with dibutyryl cAMP blocked NF-B activation.
How cAMP generated by activation of cells with -MSH inhibits NF-B
activation was also investigated. That inhibitors of PKA reversed the
suppressive effect of -MSH suggests that cAMP may act by activating
this kinase. This possibility is intriguing because it has been shown
that PKA-mediated phosphorylation of NF-B is involved in inducible
and constitutive activation of NF-B (32, 33). It was also shown that
the catalytic subunit of PKA associates with IB, the inhibitory
subunit of NF-B, in the cytoplasm (34). On stimulation of cells with
either LPS or IL-1, PKA is activated, leading to phosphorylation of the
p65 subunit of NF-B and, in turn, to NF-B’s translocation to the
nucleus (34). As the PKA activation observed in these studies was cAMP
independent, it is unlikely that this is a mechanism of suppression of
NF-B activation by -MSH. Besides, in our studies PKA activation
resulted not in activation of NF-B, as shown by Zhong et al. (34),
but, rather, in its suppression. Also, an inhibitor of PKC, H7, had no
effect on the suppressive effect of -MSH, indicating specificity.
Our results, however, are consistent with those of other reports, which
show that elevation of cAMP reduces NF-B activity (35, 36, 37, 38). How
elevation of cAMP reduces NF-B activity, however, is controversial.
Ollivier et al. (37) found inhibition of NF-B-mediated transcription
by elevated cAMP or by overexpression of PKA without any inhibition of
the IB degradation or nuclear translocation of p65. In contrast,
Chen and Rothenberg (35) and Neumann et al. (36) reported that the
effects of cAMP are mediated through stabilization of IB and
impairment of the nuclear transport of p65. Similar to the latter
observations, we found that elevation of intracellular cAMP induced by
-MSH inhibits IB degradation and p65 translocation to the
nucleus as well as gene transcription. It is possible that cAMP
inhibits NF-B activation through inhibition of the mitogen-activated
protein kinase kinase-c-Jun N-terminal kinase pathway, as
overexpression of mitogen-activated protein kinase kinase reversed the
inhibitory effects of cAMP on NF-B activation (38).
We found that, besides that induced by TNF, NF-B activation induced
by LPS, ceramide, and okadaic acid was also inhibited by -MSH. That
the NF-B activation induced by PMA and H2O2
was inhibited only partially suggests a difference in the mechanisms of
activation. This is in agreement with studies showing that PMA
activates NF-B by a mechanism different from that of TNF and okadaic
acid (39). For instance, inhibitors of PKC block PMA-induced, but not
TNF-induced, activation of NF-B (40). Our data indicate that various
signals leading to activation of NF-B converge at or before the
IB target, which, in turn, suggests the possibility of a common
upstream effector.
Although there are several small molecule and nonpeptide inhibitors of
cell signaling known to block NF-B activation, there are very few
normal physiologic peptide hormones reported to block NF-B
activation. It was recently shown that IL-4, IL-10, and growth hormone
can block NF-B activation, but their mechanisms of action were not
reported (6, 41, 42).
We demonstrated that -MSH inhibits the NF-B-dependent gene
transcription activated by TNF. There are a large number of genes
involved in cellular inflammation that require NF-B activation,
including MHC-1, TNF, IL-1, IL-6, granulocyte colony-stimulating
factor, chemokines, cyclo-oxygenase, lipoxygenase, complement receptor,
cell adhesion proteins, and nitric oxide synthase (13). -MSH has
been shown to inhibit nitric oxide synthesis (9), TNF production (8),
neutrophil migration, and PG synthesis (10), all of which are
NF-B-dependent and are involved in inflammation. In addition, the
p65 subunit of NF-B has been colocalized with -MSH in the rat
brain, suggesting a close relationship (43). As inhibitors of NF-B
activation have been exploited to treat various inflammatory diseases
(44), -MSH may be useful in those situations. Overall, we conclude
that because it has no known pharmacologic toxicity and is able to
suppress NF-B activation by various agents, -MSH has potential
for use in conditions initiated through NF-B activation, such as
inflammatory diseases, HIV replication in AIDS, and septic shock.
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Acknowledgments |
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Footnotes |
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2 Abbreviations used in this paper: -MSH, -melanocyte-stimulating hormone; IB, inhibitory subunit of nuclear factor-B; H-7, 1-(5-isoquinolinyl sulfonyl)-2-methyl piperazine; Rp-cAMPS, adenosine cyclic 3',5'-phosphorothiolate triethylammonium salt; AP-1, activating protein-1; CAT, chloramphenicol acetyltransferase; EMSA, electrophoretic mobility shift assay; ddAdo, 3',5'-dideoxyadenosine; PKA, protein kinase A; PKC, protein kinase C; MDR, multidrug resistance.
Received for publication January 16, 1998. Accepted for publication May 15, 1998.
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References |
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 S. J. Getting, C. W. Lam, G. Leoni, F. N. E. Gavins, P. Grieco, and M. Perretti [D-Trp8]-{gamma}-Melanocyte-Stimulating Hormone Exhibits Anti-Inflammatory Efficacy in Mice Bearing a Nonfunctional MC1R (Recessive Yellow e/e Mouse) Mol. Pharmacol., December 1, 2006; 70(6): 1850 - 1855. [Abstract] [Full Text] [PDF]
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S. J. Getting, C. W. Lam, A. S. Chen, P. Grieco, and M. Perretti Melanocortin 3 receptors control crystal-induced inflammation FASEB J, November 1, 2006; 20(13): 2234 - 2241. [Abstract] [Full Text] [PDF]
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L. Kang, K. W. McIntyre, K. M. Gillooly, Y. Yang, J. Haycock, S. Roberts, A. Khanna, T. F. Herpin, G. Yu, X. Wu, et al. A selective small molecule agonist of the melanocortin-1 receptor inhibits lipopolysaccharide-induced cytokine accumulation and leukocyte infiltration in mice J. Leukoc. Biol., October 1, 2006; 80(4): 897 - 904. [Abstract] [Full Text] [PDF]
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 C Maaser, K Kannengiesser, C Specht, A Lugering, T Brzoska, T A Luger, W Domschke, and T Kucharzik Crucial role of the melanocortin receptor MC1R in experimental colitis Gut, October 1, 2006; 55(10): 1415 - 1422. [Abstract] [Full Text] [PDF]
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 N. R. Vulliemoz, E. Xiao, L. Xia-Zhang, M. Ferin, and S. L. Wardlaw Melanocortin Modulation of Inflammatory Cytokine and Neuroendocrine Responses to Endotoxin in the Monkey Endocrinology, April 1, 2006; 147(4): 1878 - 1883. [Abstract] [Full Text] [PDF]
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G.-S. Liu, L.-F. Liu, C.-J. Lin, J.-C. Tseng, M.-J. Chuang, H.-C. Lam, J.-K. Lee, L.-C. Yang, J. H. Y. Chan, S.-L. Howng, et al. Gene Transfer of Pro-opiomelanocortin Prohormone Suppressed the Growth and Metastasis of Melanoma: Involvement of {alpha}-Melanocyte-Stimulating Hormone-Mediated Inhibition of the Nuclear Factor {kappa}B/Cyclooxygenase-2 Pathway Mol. Pharmacol., February 1, 2006; 69(2): 440 - 451. [Abstract] [Full Text] [PDF]
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 J. Deng, X. Hu, P. S. T. Yuen, and R. A. Star {alpha}-Melanocyte-stimulating Hormone Inhibits Lung Injury after Renal Ischemia/Reperfusion Am. J. Respir. Crit. Care Med., March 15, 2004; 169(6): 749 - 756. [Abstract] [Full Text] [PDF]
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 A. Catania, S. Gatti, G. Colombo, and J. M. Lipton Targeting Melanocortin Receptors as a Novel Strategy to Control Inflammation Pharmacol. Rev., March 1, 2004; 56(1): 1 - 29. [Abstract] [Full Text] [PDF]
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 M. Bohm, M. Raghunath, C. Sunderkotter, M. Schiller, S. Stander, T. Brzoska, T. Cauvet, H. B. Schioth, T. Schwarz, and T. A. Luger Collagen Metabolism Is a Novel Target of the Neuropeptide {alpha}-Melanocyte-stimulating Hormone J. Biol. Chem., February 20, 2004; 279(8): 6959 - 6966. [Abstract] [Full Text] [PDF]
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A. Catania, G. Colombo, A. Carlin, L. Garofalo, S. Gatti, R. Buffa, N. Carboni, L. Rosso, L. Santambrogio, L. Cantalamessa, et al. Autocrine inhibitory influences of {alpha}-melanocyte-stimulating hormone in malignant pleural mesothelioma J. Leukoc. Biol., February 1, 2004; 75(2): 253 - 259. [Abstract] [Full Text] [PDF]
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 K. Shiratori, K. Ohgami, I. B. Ilieva, Y. Koyama, K. Yoshida, and S. Ohno Inhibition of Endotoxin-Induced Uveitis and Potentiation of Cyclooxygenase-2 Protein Expression by {alpha}-Melanocyte-Stimulating Hormone Invest. Ophthalmol. Vis. Sci., January 1, 2004; 45(1): 159 - 164. [Abstract] [Full Text] [PDF]
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K. Abeyama, K.-i. Kawahara, S. Iino, T. Hamada, S.-i. Arimura, K. Matsushita, T. Nakajima, and I. Maruyama Antibiotic cyclic AMP signaling by "primed" leukocytes confers anti-inflammatory cytoprotection J. Leukoc. Biol., November 1, 2003; 74(5): 908 - 915. [Abstract] [Full Text] [PDF]
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E. Xiao, L. Xia-Zhang, N. R. Vulliemoz, M. Ferin, and S. L. Wardlaw Leptin Modulates Inflammatory Cytokine and Neuroendocrine Responses to Endotoxin in the Primate Endocrinology, October 1, 2003; 144(10): 4350 - 4353. [Abstract] [Full Text] [PDF]
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S.-W. Yoon, S.-H. Goh, J.-S. Chun, E.-W. Cho, M.-K. Lee, K.-L. Kim, J.-J. Kim, C.-J. Kim, and H. Poo {alpha}-Melanocyte-stimulating Hormone Inhibits Lipopolysaccharide-induced Tumor Necrosis Factor-{alpha} Production in Leukocytes by Modulating Protein Kinase A, p38 Kinase, and Nuclear Factor {kappa}B Signaling Pathways J. Biol. Chem., August 29, 2003; 278(35): 32914 - 32920. [Abstract] [Full Text] [PDF]
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 S. J. Getting, H. B. Schioth, and M. Perretti Dissection of the Anti-Inflammatory Effect of the Core and C-Terminal (KPV) {alpha}-Melanocyte-Stimulating Hormone Peptides J. Pharmacol. Exp. Ther., August 1, 2003; 306(2): 631 - 637. [Abstract] [Full Text] [PDF]
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E. Xiao, L. Xia-Zhang, N. R. Vulliemoz, M. Ferin, and S. L. Wardlaw Agouti-Related Protein Stimulates the Hypothalamic-Pituitary-Adrenal (HPA) Axis and Enhances the HPA Response to Interleukin-1 in the Primate Endocrinology, May 1, 2003; 144(5): 1736 - 1741. [Abstract] [Full Text] [PDF]
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 S. J. Getting, H. C. Christian, C. W. Lam, F. N. E. Gavins, R. J. Flower, H. B. Schioth, and M. Perretti Redundancy of a Functional Melanocortin 1 Receptor in the Anti-inflammatory Actions of Melanocortin Peptides: Studies in the Recessive Yellow (e/e) Mouse Suggest an Important Role for Melanocortin 3 Receptor J. Immunol., March 15, 2003; 170(6): 3323 - 3330. [Abstract] [Full Text] [PDF]
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T. E. Scholzen, C. Sunderkotter, D.-H. Kalden, T. Brzoska, M. Fastrich, T. Fisbeck, C. A. Armstrong, J. C. Ansel, and T. A. Luger {alpha}-Melanocyte Stimulating Hormone Prevents Lipopolysaccharide-Induced Vasculitis by Down-Regulating Endothelial Cell Adhesion Molecule Expression Endocrinology, January 1, 2003; 144(1): 360 - 370. [Abstract] [Full Text] [PDF]
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V. Gavrilyuk, C. Dello Russo, M. T. Heneka, D. Pelligrino, G. Weinberg, and D. L. Feinstein Norepinephrine Increases Ikappa Balpha Expression in Astrocytes J. Biol. Chem., August 9, 2002; 277(33): 29662 - 29668. [Abstract] [Full Text] [PDF]
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 T. R. Bernik, S. G. Friedman, M. Ochani, R. DiRaimo, L. Ulloa, H. Yang, S. Sudan, C. J. Czura, S. M. Ivanova, and K. J. Tracey Pharmacological Stimulation of the Cholinergic Antiinflammatory Pathway J. Exp. Med., March 18, 2002; 195(6): 781 - 788. [Abstract] [Full Text] [PDF]
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 T. Ichiyama, M. Nishikawa, T. Yoshitomi, S. Hasegawa, T. Matsubara, T. Hayashi, and S. Furukawa Clarithromycin Inhibits NF-{kappa}B Activation in Human Peripheral Blood Mononuclear Cells and Pulmonary Epithelial Cells Antimicrob. Agents Chemother., January 1, 2001; 45(1): 44 - 47. [Abstract] [Full Text]
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S. J. Getting, G. H. Allcock, R. Flower, and M. Perretti Natural and synthetic agonists of the melanocortin receptor type 3 possess anti-inflammatory properties J. Leukoc. Biol., January 1, 2001; 69(1): 98 - 104. [Abstract] [Full Text]
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W. Barcellini, G. Colombo, L. La Maestra, G. Clerici, L. Garofalo, A. T. Brini, J. M. Lipton, and A. Catania {alpha}-Melanocyte-stimulating hormone peptides inhibit HIV-1 expression in chronically infected promonocytic U1 cells and in acutely infected monocytes J. Leukoc. Biol., November 1, 2000; 68(5): 693 - 699. [Abstract] [Full Text]
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 N. Ouchi, S. Kihara, Y. Arita, Y. Okamoto, K. Maeda, H. Kuriyama, K. Hotta, M. Nishida, M. Takahashi, M. Muraguchi, et al. Adiponectin, an Adipocyte-Derived Plasma Protein, Inhibits Endothelial NF-{kappa}B Signaling Through a cAMP-Dependent Pathway Circulation, September 12, 2000; 102(11): 1296 - 1301. [Abstract] [Full Text] [PDF]
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 L. Airaghi, L. Garofalo, M. G. Cutuli, R. Delgado, A. Carlin, M. T. Demitri, S. Badalamenti, G. Graziani, J. M. Lipton, and A. Catania Plasma concentrations of {alpha}-melanocyte-stimulating hormone are elevated in patients on chronic haemodialysis Nephrol. Dial. Transplant., August 1, 2000; 15(8): 1212 - 1216. [Abstract] [Full Text] [PDF]
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 A. Slominski, J. Wortsman, T. Luger, R. Paus, and S. Solomon Corticotropin Releasing Hormone and Proopiomelanocortin Involvement in the Cutaneous Response to Stress Physiol Rev, July 1, 2000; 80(3): 979 - 1020. [Abstract] [Full Text] [PDF]
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 S. K. Manna, N. K. Sah, R. A. Newman, A. Cisneros, and B. B. Aggarwal Oleandrin Suppresses Activation of Nuclear Transcription Factor-{{kappa}}B, Activator Protein-1, and c-Jun NH2-Terminal Kinase Cancer Res., July 1, 2000; 60(14): 3838 - 3847. [Abstract] [Full Text]
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S. K. Manna, A. Mukhopadhyay, and B. B. Aggarwal Human Chorionic Gonadotropin Suppresses Activation of Nuclear Transcription Factor-kappa B and Activator Protein-1 Induced by Tumor Necrosis Factor J. Biol. Chem., April 28, 2000; 275(18): 13307 - 13314. [Abstract] [Full Text] [PDF]
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M. Delgado and D. Ganea Vasoactive Intestinal Peptide and Pituitary Adenylate Cyclase-activating Polypeptide Inhibit Interleukin-12 Transcription by Regulating Nuclear Factor kappa B and Ets Activation J. Biol. Chem., November 5, 1999; 274(45): 31930 - 31940. [Abstract] [Full Text] [PDF]
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S. Adachi, T. Nakano, H. Vliagoftis, and D. D. Metcalfe Receptor-Mediated Modulation of Murine Mast Cell Function by {alpha}-Melanocyte Stimulating Hormone J. Immunol., September 15, 1999; 163(6): 3363 - 3368. [Abstract] [Full Text] [PDF]
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