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Environmental Estrogens Induce Mast Cell Degranulation and Enhance IgE-Mediated Release of Allergic Mediators

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Prevalence and morbidity of allergic diseases have increased over the last decades. Based on the recently recognized differences in asthma prevalence between the sexes, we have examined the effect of endogenous estrogens on a key element of the allergic response. Some lipophilic pollutants have estrogen-like activities and are termed environmental estrogens. These pollutants tend to degrade slowly in the environment and to bioaccumulate and bioconcentrate in the food chain; they also have long biological half-lives. Our goal in this study was to identify possible pathogenic roles for environmental estrogens in the development of allergic diseases. We screened a number of environmental estrogens for their ability to modulate the release of allergic mediators from mast cells. We incubated a human mast cell line and primary mast cell cultures derived from bone marrow of wild type and estrogen receptor alpha (ER-alpha)-deficient mice with environmental estrogens with and without estradiol or IgE and allergens. We assessed degranulation of mast cells by quantifying the release of beta-hexosaminidase. All of the environmental estrogens tested caused rapid, dose-related release of beta-hexosaminidase from mast cells and enhanced IgE-mediated release. The combination of physiologic concentrations of 17beta-estradiol and several concentrations of environmental estrogens had additive effects on mast cell degranulation. Comparison of bone marrow mast cells from ER-alpha-sufficient and ER-alpha-deficient mice indicated that much of the effect of environmental estrogens was mediated by ER-alpha. Our findings suggest that estrogenic environmental pollutants might promote allergic diseases by inducing and enhancing mast cell degranulation by physiologic estrogens and exposure to allergens.
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48
VOLUME 115 | NUMBER 1 | January 2007
Environmental Health Perspectives
Research
The prevalence and morbidity of asthma and
other allergic diseases have increased dramati-
cally during the last 30 years, particularly in
industrial countries (Burr et al. 2006). The
onset of asthma most commonly occurs in
early childhood (Yunginger et al. 1992).
Asthma is more common in males during
infancy, childhood, and preadolescence
(Yunginger et al. 1992). However, from late
adolescence to middle age, females have a
higher prevalence and morbidity from asthma
(De Marco et al. 2002; Yunginger et al.
1992). Although the increase in overall preva-
lence and the cause of these pattern differ-
ences between the sexes are not well
understood, we questioned whether female
gonadal hormones and their mimetics might
be involved.
We recently found that physiologic con-
centrations of estradiol (E
2
) rapidly stimulate
murine and human mast cell lines (RBL-2H3
and HMC-1) and primary cultures of bone
marrow–derived mast cells (BMMC) to release
β-hexosaminadase (β-hex), a marker for the
granules that contain preformed allergic medi-
ators (Zaitsu et al. 2006). These low doses of
E
2
also enhanced the synthesis and release of
leukotriene C
4
(LTC
4
) by RBL-2H3 cells. In
addition to these direct effects, E
2
potentiated
IgE-dependent synthesis and release of β-hex,
and particularly LTC
4
. The finding that the
estrogen receptor (ER) antagonists tamoxifen
and ICI 182,780 inhibited these effects sug-
gested that these estrogenic effects were medi-
ated through specific ERs (ER-α or ER-β).
This proposition was substantiated by demon-
strating that BMMCs derived from ER-α
knockout (KO) mice did not degranulate in
response to E
2
. We also analyzed the expres-
sion of ER-α and ER-β by reverse transcrip-
tase-polymerase chain reaction and could
detect only ER-α on RBL-2H3, HMC-1,
and BMMCs (Zaitsu et al. 2006). Another
recent study provided evidence for estrogen
effects on allergic sensitization/reactions by
showing a relationship between an ER-α gene
(ESR1) polymorphism and airway hypersensi-
tivity, and an age-related decline in lung
function in females with asthma (Dijkstra
et al. 2006).
Estrogens and other steroid hormones use
two different major cellular pathways to exert
their regulatory effects. One pathway is via
genomic receptors acting as transcription fac-
tors on gene expression. However, an alterna-
tive pathway acting via plasma membrane
receptors is more often involved in the rapid
effects of steroids occurring within seconds to
minutes (Watson et al. 1999; Watson and
Gametchu 2003). This nongenomic pathway
is involved in secretory responses to both
physiologic and nonphysiologic estrogens
(Bulayeva et al. 2005).
Many environmental pollutants have
estrogen-like activities and thus are termed
environmental estrogens or xenoestrogens
(Newbold et al. 2006; Wozniak et al. 2005).
These components can be involved in both
genomic and nongenomic pathways of estro-
gen action, but have recently been shown to
be very potent when acting via the non-
genomic pathway (Wozniak et al. 2005),
although they are very weak activators of the
genomic pathway. If environmental estrogens
act at such low levels, then the widespread
presence of these compounds in our environ-
ment are of concern as causes for the increas-
ing prevalence of diseases such as asthma.
Examples of environmental estrogens
include the dioxins, dichlorodiphenyl-
trichloroethane (DDT) and its metabolite
dichlorodiphenylethylene (DDE), hexachloro-
cyclohexane, polychlorinated biphenyls
(PCBs), and alkylphenols and their derivatives
(nonylphenol, octylphenol, bisphenol A). The
most common source of these pollutants is
through contaminated water and foods
(Aravindakshan et al. 2004; Falconer et al.
2006). We therefore questioned whether envi-
ronmental estrogens could have effects on
allergic sensitization and clinically relevant
reactions, such as for asthma. The goal of the
present study was to identify possible mecha-
nisms by which environmental estrogens,
alone or in combination with endogenous
Address correspondence to T. Midoro-Horiuti, Child
Health Research Center, University of Texas Medical
Branch, 2.300 Children’s Hospital, 301 University
Blvd., Galveston, TX 77555-0366 USA. Telephone:
(409) 772-3832. Fax: (409) 772-1761. E-mail:
tmidoro@utmb.edu
This work was a pilot project supported by the
NIEHS (National Institute of Environmental Health
Sciences) Center for Environmental Science at the
University of Texas Medical Branch (pilot project
grant P30 E06676 to T.M.H.) and by grants R01
AI052428 (R.M.G.) and K08 AI055792 (T.M.H.)
from the National Institute of Allergy and Infectious
Diseases.
The authors declare they have no competing
financial interests.
Received 25 May 2006; accepted 3 October 2006.
Environmental Estrogens Induce Mast Cell Degranulation and Enhance
IgE-Mediated Release of Allergic Mediators
Shin-ichiro Narita,
1
Randall M. Goldblum,
1
Cheryl S. Watson,
2
Edward G. Brooks,
1
D. Mark Estes,
1
Edward M. Curran,
1
and Terumi Midoro-Horiuti
1
1
Department of Pediatrics, Child Health Research Center; and
2
Department of Biochemistry and Molecular Biology, University of Texas
Medical Branch, Galveston, Texas, USA
BACKGROUND: Prevalence and morbidity of allergic diseases have increased over the last decades.
Based on the recently recognized differences in asthma prevalence between the sexes, we have exam-
ined the effect of endogenous estrogens on a key element of the allergic response. Some lipophilic
pollutants have estrogen-like activities and are termed environmental estrogens. These pollutants
tend to degrade slowly in the environment and to bioaccumulate and bioconcentrate in the food
chain; they also have long biological half-lives.
O
BJECTIVES: Our goal in this study was to identify possible pathogenic roles for environmental
estrogens in the development of allergic diseases.
M
ETHODS: We screened a number of environmental estrogens for their ability to modulate the
release of allergic mediators from mast cells. We incubated a human mast cell line and primary
mast cell cultures derived from bone marrow of wild type and estrogen receptor α (ER-α)–deficient
mice with environmental estrogens with and without estradiol or IgE and allergens. We assessed
degranulation of mast cells by quantifying the release of β-hexosaminidase.
R
ESULTS: All of the environmental estrogens tested caused rapid, dose-related release of
β-hexosaminidase from mast cells and enhanced IgE-mediated release. The combination of physi-
ologic concentrations of 17β-estradiol and several concentrations of environmental estrogens had
additive effects on mast cell degranulation. Comparison of bone marrow mast cells from ER-α
sufficient and ER-α–deficient mice indicated that much of the effect of environmental estrogens
was mediated by ER-α.
C
ONCLUSIONS: Our findings suggest that estrogenic environmental pollutants might promote
allergic diseases by inducing and enhancing mast cell degranulation by physiologic estrogens and
exposure to allergens.
K
EY WORDS: allergy, asthma, β-hexosaminidase, environmental estrogen, estradiol, estrogen
receptor α, IgE, mast cells. Environ Health Perspect 115:48–52 (2007). doi:10.1289/ehp.9378 avail-
able via http://dx.doi.org/ [Online 3 October 2006]
estrogens, might promote the development of
allergic diseases.
Materials and Methods
Cells and cell culture. We obtained the
HMC-1 human mast cell line from J.H.
Butterfield (Mayo Clinic, Rochester, MN)
(Butterfield et al. 1988). Cells were cultured
in Iscove's modified Dulbecco's medium
(IMDM; Cellgro, Kansas City, MO) with
10% iron-supplemented calf serum (Hyclone,
South Logan, UT). To avoid exposure to
estrogens during culture, we used steroid-
stripped fetal calf serum (FCS) and phenol
red–free media throughout this study, as
described previously (Lambert et al. 2005).
We developed primary cultures of bone
marrow-derived mast cells (BMMC) from the
marrow of the femurs of C57B6 mice, as
described by Odom et al. (2004). We
obtained wild type (WT) C57B6 mice from
the Jackson Laboratory (Houston, TX) and
produced ER-α KO mice by back-cross of the
previously generated heterozygous ER-α KO
mice (Lambert et al. 2005). BMMC cultures
contained > 98% pure mast cells after
4 weeks, as assessed by toluidine blue staining.
For the last 48 hr before harvesting, we cul-
tured these BMMCs in medium with estro-
gen-stripped FCS (Invitrogen, Carlsbad,
CA). We used BMMCs to confirm that the
effects of E
2
were through ER-α, by compar-
ing the cells from WT and ER-α KO mice.
All animal experimental protocols were
approved by the University of Texas Medical
Branch Institutional Animal Care and Use
Committee. The animals were treated
humanely and with regard for alleviation of
suffering.
Estrogens. We obtained 17β-estradiol from
Sigma-Aldrich Corporation (St. Louis, MO).
We used the following environmental estro-
gens in our studies: organochloride pesticides
or their metabolites (endosulfan, dieldrin, and
DDE); a by-product of plastics manufacturing
(nonylphenol); and the PCBs Aroclor 1242
and Aroclor 1254. We obtained DDE and
endosulfan from Ultra Scientific (North
Kingstown, RI) and nonylphenol, dieldrin,
Aroclor 1242, and Aroclor 1254 from Sigma.
Patient serum samples. We obtained sam-
ples of sera from patients who had a history of
asthma and had a positive skin prick test to
house dust mites (DM). We complied with
all applicable U.S. requirements and/or inter-
national regulations (including institutional
review board approval), and human partici-
pants gave written informed consent prior to
the study.
Mast cell activation experiments. We har-
vested cells by trypsinization, cultured them
on 96-well plates for 2 days to allow mem-
brane receptors to be resynthesized, and then
stimulated cells with various concentrations of
E
2
and environmental estrogens for 30 min.
To examine the interaction between exposure
to environmental estrogens and allergens in
the release of allergic mediators, we sensitized
BMMC for 1 hr with 100 ng/mL mouse
anti-dinitrophenyl (DNP) IgE antibody
(Sigma-Aldrich) and HMC-1 cells for 90 min
with a 1:5 dilution of patient serum. After
washing away unbound IgE, we stimulated
cells with DNP-bovine serum albumin (BSA)
complexes (10 haptenes per carrier molecule
used at 10 ng/mL; Biosearch Technologies,
Inc., Novato CA) or 0.75 AU/mL of dust
mite allergen extract (Dermatophagoides fari-
nae; Hollister-Stier, Spokane, WA) for 30 min
in the presence or absence of E
2
or environ-
mental estrogens. We performed all mediator
measurements in duplicate.
Assessment of degranulation by release of
the granular protein β-hex. Enzymatic assays
for β-hex have been used extensively to assess
the extracellular release of mast cell and
basophil granule contents (Dastych et al.
1999). We stimulated cells (2 × 10
4
) in
Tyrode’s buffer (Dastych et al. 1999) contain-
ing various concentrations of E
2
. We meas-
ured β-hex release as previously described
(Dastych et al. 1999), using p-nitrophenyl-N-
acetyl-β-
D
-glucopyranoside (8 mM; Sigma-
Aldrich) as the substrate. We expressed the
amount of β-hex release into media as the per-
centage of the total amount of β-hex originally
in the cells [% release = 100 × (experimental
β-hex release – spontaneous β-hex release)
÷ total cellular β-hex].
Statistical analyses. Data were expressed as
the mean ± SE. Statistical analysis was per-
formed by one-way analysis of variance.
Where differences between groups were pre-
sent, they were further analyzed by the multi-
ple comparisons (Bonferroni) for Figure 1 and
Student t-test for Figures 2–5. A p-value of
< 0.05 was defined as statistically significant.
Results
Environmental estrogens induce degranulation
of HMC-1 cells. We performed a series of
experiments to screen for the effects of various
concentrations (1 × 10
–12
–10
–8
M) of E
2
and
six different environmental estrogens on mast
Environmental estrogens enhance mast cell degranulation
Environmental Health Perspectives
VOLUME 115 | NUMBER 1 | January 2007
49
20
15
10
5
0
EE [log(M)]
β-hex (% release)
10
–12
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
E
2
Dieldrin
Endosulfan
DDE
Nonylphenol
Aroclor 1254
Aroclor 1242
10
–11
10
–10
10
–9
10
–8
Figure 1. Release of β-hex from HMC-1 after incu-
bation with six different environmental estrogens
(EEs): E
2
, dieldrin, endosulfan, DDE, nonylphenol,
Aroclor 1254, and Aroclor 1242. Experiments were
conducted in triplicate and expressed as mean ± SE.
*
p
< 0.05 vs. phosphate buffered saline control.
20
15
10
5
0
E
2
alone
β-hex (% release)
Dieldrin
Endosulfan
DDE
Nonylphenol
Aroclor 1254
Aroclor 1242
*
*
10
–11
E
2
EE
EE + E
2
Figure 2. Additive effects of environmental estro-
gens (EEs) and E
2
on β-hex release from HMC-1
cells incubated with 10
–11
M E
2
, dieldrin, endosulfan,
DDE, nonylphenol, Aroclor 1254, or Aroclor 1242
alone; or each EE plus E
2
. Experiments were con-
ducted in triplicate and expressed as mean ± SE.
*
p
< 0.05 compared with EE alone.
Figure 3. Effects of environmental estrogens (EEs) on IgE-dependent degranulation from HMC-1 cells and
BMMC. (
A
) Release of β-hex from HMC-1 cells by 0.75 AU/mL DM alone; 10 pM of dieldrin, endosulfan, DDE,
nonylphenol, Aroclor 1254, or Aroclor 1242 alone; or each EE plus DM. (
B
) Release of β-hex from BMMC by
anti-DNP IgE/DNP-BSA alone; 10
–13
M dieldrin, 10
–12
M endosulfan, 10
–11
M DDE, 10
–11
M nonylphenol,
10
–9
M Aroclor 1254, or 10
–12
M Aroclor1242 alone; or each EE plus anti-DNP IgE/DNP-BSA. Experiments
were conducted in triplicate and expressed as mean ± SE.
*
p
< 0.05 compared with EE alone.
12
10
8
6
4
2
0
DM alone
β-hex (% release)
Dieldrin
Endosulfan
DDE
Nonylphenol
Aroclor 1254
Aroclor 1242
*
*
*
*
*
A
DM
EE
EE + DM
DNP alone
Dieldrin
Endosulfan
DDE
Nonylphenol
Aroclor 1254
Aroclor 1242
15
10
5
0
*
*
*
*
*
B
β-hex (% release)
DNP-BSA
EE
EE + DNP-BSA
cell degranulation, using release of β-hex from
HMC-1 cells as a marker for degranulation
and release of allergic mediators. Figure 1
shows that all of the environmental estrogens
tested except Aroclor 1254 caused the release
of a significant portion of intracellular β-hex at
concentrations ranging from 10
–11
to 10
–8
M
after 30 min of stimulation. For comparison, a
Ca
2+
ionophore induced approximately 30%
release of intracellular β-hex (data not shown),
presumably because not all β-hex resides in
releasable granules. Therefore the environmen-
tal estrogens alone released up to 50% of the
releasable granular contents.
Combined effects of E
2
and environmen-
tal estrogens on degranulation of HMC-1
cells. To analyze the effect of combinations of
endogenous estrogen with environmental
estrogens, we incubated HMC-1 cells with
combinations of suboptimal concentrations of
E
2
(1 × 10
–11
M) and varying concentrations
of all six estrogenic compounds. We used
suboptimal concentrations to test for additive
effects, because the release of β-hex from cells
incubated with an optimal dose of the estro-
genic compounds was not significantly
increased by other estrogens (data not shown).
Figure 2 shows that these combinations of
estrogenic compounds induced degranulation
more effectively than either of the compounds
alone at these concentrations. The resulting
stimulations were approximately additive and
again were fairly rapid (< 30 min).
Environmental estrogens enhance IgE-
mediated degranulation of HMC-1 cells and
BMMC. We then evaluated the effect of envi-
ronmental estrogens on IgE-dependent
degranulation using our responsive cell sys-
tems, which were sensitized with IgE anti-
bodies from the appropriate species. When
HMC-1 cells sensitized with human IgE were
subsequently exposed to combination of DM
allergen and 10
–13
–10
–9
M environmental
estrogens, the release of β-hex was signifi-
cantly enhanced compared to cells exposed to
the same concentration of DM allergen alone
(Figure 3A). This was the case for all of the
environmental estrogens tested.
We also tested the effects of environmental
estrogens on IgE-induced degranulation of pri-
mary cultures of BMMCs. We sensitized
BMMCs with monoclonal IgE anti-DNP anti-
bodies and stimulated them with DNP-BSA in
the presence of 10
–13
–10
–9
M concentrations
of our six test environmental estrogens. Each
of these environmental estrogens, except
nonylphenol, significantly enhanced the β-hex
release induced by DM (Figure 3B). We
assessed the dose–response relationship
for one of these environmental estrogens
(Aroclor 1242) to define the concentrations
that had the strongest additive effects on IgE-
mediated degranulation and the shape of the
dose–response curve. Concentrations of
Aroclor 1242 of 10
–14
–10
–12
M significantly
enhanced the effect of IgE cross-linking,
whereas higher concentrations of Aroclor 1242
also appeared to increase the response, but not
to significant levels (Figure 4).
ER-α is required for β-hex release induced
by some concentrations of environmental estro-
gens. To determine which types of ERs were
involved in the degranulation of mast cells by
environmental estrogens, we performed a
dose–response analysis on BMMCs derived
from WT versus ER-α KO mice. Figure 5
indicates that some concentrations of environ-
mental estrogens induce significantly more
degranulation of mast cells from the WT com-
pared with the ER-α KO mice (Figure 5).
However, the degranulation response to some
concentrations of environmental estrogens was
not significantly reduced by the absence of
ER-α expression. In fact, many of the concen-
trations of environmental estrogens alone cause
significant degranulation of ER-α–deficient
mast cells. This is in contrast to the effects of
E
2
, which seems to require ER-α, because E
2
did not induce significant degranulation from
BMMC derived from ER-α KO mice (Zaitsu
et al. 2006).
Discussion
In this study, we examined the effects of envi-
ronmental estrogens—alone and in combina-
tion with physiologic concentrations of
E
2
—on the activation of a human mast cell
line and primary cultures of murine mast cells.
We found that, like E
2
, low concentrations of
environmental estrogens caused a rapid, partial
Narita et al.
50
VOLUME 115 | NUMBER 1 | January 2007
Environmental Health Perspectives
20
15
10
5
0
β-hex (% release)
10
0
10
–14
10
–13
10
–12
10
–11
10
–10
*
*
*
Aroclor 1242 [log (M)]
DNP-BSA
Aroclor 1242
Aroclor 1242 + DNP-BSA
Figure 4. Dose–response effects of DNP-BSA,
Aroclor 1242, and Aroclor 1242 plus DNP-BSA on
IgE-mediated degranulation of BMMCs from WT
mice. Experiments were conducted in triplicate
and expressed as mean ± SE.
*p
< 0.05 compared with Aroclor 1242 alone.
Figure 5. Requirement for ER-α expression for degranulation of BMMCs from WT and ER-α KO mice shown by the release of β-hex by various concentrations of
endosulfan (
A
), DDE (
B
), dieldrin (
C
), nonylphenol (
D
), Aroclor 1254 (
E
), and Aroclor 1242 (
F
). Experiments were conducted in triplicate and expressed as mean ± SE.
*p
< 0.05 WT compared with KO.
6
5
4
3
2
1
0
β-hex (% release)
A
10
–12
10
–11
10
–10
*
10
–9
10
–8
Endosulfan [log (M)]
WT
ER-α KO
6
5
4
3
2
1
0
*
*
Nonylphenol [log (M)]
D
B
6
5
4
3
2
1
0
*
*
*
DDE [log (M)]
*
6
5
4
3
2
1
0
Aroclor 1254 [log (M)]
E
6
5
4
3
2
1
0
Aroclor 1242 [log (M)]
F
6
5
4
3
2
1
0
C
*
*
*
*
Dieldrin [log (M)]
β-hex (% release)
β-hex (% release)
β-hex (% release)
β-hex (% release)
β-hex (% release)
10
–12
10
–11
10
–10
10
–9
10
–8
10
–12
10
–11
10
–10
10
–9
10
–8
10
–13
10
–12
10
–11
10
–10
10
–9
10
–8
10
–11
10
–10
10
–9
10
–8
10
–7
10
–12
10
–11
10
–10
10
–9
10
–8
Environmental estrogens enhance mast cell degranulation
Environmental Health Perspectives
VOLUME 115 | NUMBER 1 | January 2007
51
degranulation of mast cells. The range of envi-
ronmental estrogen concentrations that
induced β-hex release was somewhat broader
for environmental estrogens (10
–8
–10
–12
) com-
pared to that of E
2
[10
–9
–10
–11
(Zaitsu et al.
2006)]. However, the dose–response curves for
the environmental estrogens were similar to
that for E
2
, in that they are biphasic (inverted
U-shaped) curves. This type of response is also
typical for other steroid-induced responses
(Watson et al. 1999; Welshons et al. 2003).
Exposing HMC-1 cells to a combination of
suboptimal concentrations of E
2
and an envi-
ronmental estrogen had an additive effect on
degranulation. Environmental estrogens also
enhanced the release of β-hex induced by aller-
gen cross-linking of IgE on the surface of these
cells. However, when these mast cells were
incubated with an optimal dose of environ-
mental estrogens, the addition of E
2
did not
enhance the effects of the environmental estro-
gen alone (data not shown). Finally, BMMCs
deficient in ER-α expression had significantly
reduced responses to some concentrations of
environmental estrogens, suggesting that at
least part of the degranulating activity of envi-
ronmental estrogens on mast cells is mediated
through ER-α.
These findings taken together suggest that
the mechanisms of activation of mast cells by
environmental estrogens are similar to those
of the endogenous estrogen E
2
. Key charac-
teristics of that response are high sensitivity
and rapid onset (minutes), partial degranula-
tion, biphasic dose response, requirements for
ER-α and extracellular Ca
2+
, and additivity or
synergy with IgE cross-linking (Zaitsu et al.
2006). Many of these characteristics are also
consistent with those described for activation
of the nongenomic (membrane) form of
ER-α (Watson et al. 1999; Watson and
Gametchu 2003). However, some of the envi-
ronmental estrogens had residual activity at
some concentrations in ER-α KO mast cells.
These might be due to compound-specific
binding to truncated ER-α in the KO cells
(Kos et al. 2002) or to nonclassical ERs, such
as the newly described estrogen-binding pro-
tein GPR30 (Bologa et al. 2006; Thomas
et al. 2005), or other unrecognized receptors.
For instance, we previously described low-
dose and rapid effects of environmental estro-
gens via a membrane-resident ER-α in
pituitary tumor cells (Bulayeva and Watson
2004; Wozniak et al. 2005). In that model,
environmental estrogens in nanomolar (parts
per billion) to picomolar (parts per trillion)
concentrations induced extracellular-regulated
kinase-1 (ERK-1) and ERK-2 activation via
ER-α and Ca
2+
elevations, leading to rapid
prolactin secretion. We have not studied the
effects of environmental estrogens on these
specific signaling pathways of mast cells, but
our recent data suggests that intracellular
Ca
2+
levels rise within 1 min of exposure to
E
2
(Zaitsu et al. 2006).
In the present study, we chose endogenous
and environmental estrogen concentrations
that would mimic tissue levels that occur in
individuals after typical environmental expo-
sures (Ayotte et al. 2003; Ibarluzea et al. 2004;
Metcalfe et al. 2001; Solomon and Weiss
2002; Vartiainen et al. 1997; Wang et al.
2004). However, an additional concern is that
most environmental estrogens are present in
the environment and in tissues and fat stores in
combinations, because of their long half-lives
and co-prevalence in the environment. Our
demonstrations of additive effects between
environmental and endogenous estrogens are
the first steps toward understanding exposure
to complex mixtures of estrogenic compounds.
The results of these experiments are consistent
with the hypothesis that the effects of both
xenoestrogens and physiologic estrogens
together will determine the estrogenic impact
on an individual. This estrogenic impact is
likely to be important both for rapid disease-
promoting responses, such as mast cell activa-
tion, and for more long-term pathogenesis,
such as estrogen-induced cancers.
Some chemicals that accumulate in
women’s tissues are also transferred to their
infants during breast-feeding. This is espe-
cially true for environmental lipid-soluble
pollutants such as polyhalogenated com-
pounds, because these chemicals tend to
degrade slowly in the environment, to bio-
accumulate and bioconcentrate in the food
chain, and to have long half-lives in humans.
Although the World Health Organization
(WHO) strongly supports breast-feeding,
breast milk–monitoring studies suggest that
environmental chemicals that may affect chil-
dren’s health are transmitted through breast-
feeding (Solomon and Weiss 2002; Wang
et al. 2004). Because the fat content of breast
milk is relatively high, the concentration of
some of these pollutants is 100 times higher
in milk than in plasma (Dewailly et al. 1993).
As the final consumers in the food chain,
human infants may consume the highest con-
centrations of lipid-soluble environmental
pollutants, which might enhance their risk of
developing asthma or other allergic diseases.
Our findings on the effects of environ-
mental estrogens on mast cell degranulation
may help explain the increasing prevalence of
asthma and other allergic diseases in recent
decades. A number of sex-steroid effects on
immune system functions have been described
(Watson and Gametchu 2001), yet relatively
few have been explored mechanistically. The
results described here indicate that we must
also consider the possible impact of environ-
mental estrogens on normal immune function
and on the development and morbidity of
immunologic diseases such as asthma.
REFERENCES
Aravindakshan J, Gregory M, Marcogliese DJ, Fournier M,
Cyr DG. 2004. Consumption of xenoestrogen-contaminated
fish during lactation alters adult male reproductive function.
Toxicol Sci 81:179–189.
Ayotte P, Muckle G, Jacobson JL, Jacobson SW, Dewailly É.
2003. Assessment of pre- and postnatal exposure to poly-
chlorinated biphenyls: lessons from the Inuit Cohort Study.
Environ Health Perspect 111:1253–1258.
Bologa CG, Revankar CM, Young SM, Edwards BS, Arterburn JB,
Kiselyov AS, et al. 2006. Virtual and biomolecular screening
converge on a selective agonist for GPR30. Nat Chem Biol
2:207–212.
Bulayeva NN, Watson CS. 2004. Xenoestrogen-induced ERK-1
and ERK-2 activation via multiple membrane-initiated sig-
naling pathways. Environ Health Perspect 112:1481–1487.
Bulayeva NN, Wozniak AL, Lash LL, Watson CS. 2005.
Mechanisms of membrane estrogen-α-mediated rapid
stimulation of Ca
2+
levels and prolactin release in a pituitary
cell line. Am J Physiol Endocrinol Metab 288:E388–E397.
Burr ML, Wat D, Evans C, Dunstan FD, Doull IJ. 2006. Asthma
prevalence in 1973, 1988 and 2003. Thorax 61:296–299.
Butterfield JH, Weiler D, Dewald G, Gleich GJ. 1988. Establishment
of an immature mast cell line from a patient with mast cell
leukemia. Leuk Res 12:345–355.
Dastych J, Walczak-Drzewiecka A, Wyczolkowska J,
Metcalfe DD. 1999. Murine mast cells exposed to mer-
curic chloride release granule-associated
N
-acetyl-β-D-
hexosaminidase and secrete IL-4 and TNF-α. J Allergy
Clin Immunol 103:1108–1114.
De Marco R, Locatelli F, Cerveri I, Bugiani M, Marinoni A,
Giammanco G. 2002. Incidence and remission of asthma:
a retrospective study on the natural history of asthma in
Italy. J Allergy clin Immunol 110:228–235.
Dewailly É, Ayotte P, Bruneau S, Laliberté C, Muir DCG,
Norstrom RJ. 1993. Inuit exposure to organochlorines
through the aquatic food chain in arctic Quebec. Environ
Health Perspect 101:618–620.
Dijkstra A, Howard TD, Vonk JM, Ampleford EJ, Lange LA,
Bleecker ER, et al. 2006. Estrogen receptor 1 polymorphisms
are associated with airway hyperresponsiveness and lung
function decline, particularly in female subjects with
asthma. J Allergy Clin Immunol 117:604–611.
Falconer IR, Chapman HF, Moore MR, Ranmuthugala G. 2006.
Endocrine-disrupting compounds: a review of their chal-
lenge to sustainable and safe water supply and water
reuse. Environ Toxicol 21:181–191.
Ibarluzea JJ, Fernandez MF, Santa-Marina L, Olea-Serrano MF,
Rivas AM, Aurrekoetxea JJ, et al. 2004. Breast cancer risk
and the combined effect of environmental estrogens.
Cancer Causes Control 15:591–600.
Kos M, Denger S, Reid G, Korach KS, Gannon F. 2002. Down but
not out? A novel protein isoform of the estrogen receptor α
is expressed in the estrogen receptor α knockout mouse.
J Mol Endocrinol 29:281–286.
Lambert KC, Curran EM, Judy BM, Milligan GN, Lubahn DB,
Estes DM. 2005. Estrogen receptor α (ERα) deficiency in
macrophages results in increased stimulation of CD4
+
T
cells while 17β-estradiol acts through ERα to increase
IL-4 and GATA-3 expression in CD4
+
T cells independent of
antigen presentation. J Immunol 175:5716–5723.
Metcalfe CD, Metcalfe TL, Kiparissis Y, Koenig BG, Khan C,
Hughes RJ, et al. 2001. Estrogenic potency of chemicals
detected in sewage treatment plant effluents as determined
by in vivo assays with Japanese medaka (
Oryzias latipes
).
Environ Toxicol Chem 20:297–308.
Newbold RR, Padilla-Banks E, Jefferson WN. 2006. Adverse
effects of the model environmental estrogen diethyl-
stilbestrol are transmitted to subsequent generations.
Endocrinology 147(suppl 6):S11–S17.
Odom S, Gomez G, Kovarova M, Furumoto Y, Ryan JJ, Wright HV,
et al. 2004. Negative regulation of immunoglobulin E-
dependent allergic responses by Lyn kinase. J Exp Med
199:1491–1502.
Solomon GM, Weiss PM. 2002. Chemical contaminants in
breast milk: time trends and regional variability. Environ
Health Perspect 110:A339–A347.
Thomas P, Pang Y, Filardo EJ, Dong J. 2005. Identity of an
estrogen membrane receptor coupled to a G protein in
human breast cancer cells. Endocrinology 146:624–632.
Vartiainen T, Saarikoski S, Jaakkola JJ, Tuomisto J. 1997.
PCDD, PCDF, and PCB concentrations in human milk from
two areas in Finland. Chemosphere 34:2571–2583.
Narita et al.
52
VOLUME 115 | NUMBER 1 | January 2007
Environmental Health Perspectives
Wang SL, Lin CY, Guo YL, Lin LY, Chou WL, Chang LW. 2004.
Infant exposure to polychlorinated dibenzo-
p
-dioxins,
dibenzofurans and biphenyls (PCDD/Fs, PCBs)—correlation
between prenatal and postnatal exposure. Chemosphere
54:1459–1473.
Watson CS, Campbell CH, Gametchu B. 1999. Membrane
oestrogen receptors on rat pituitary tumour cells: immuno-
identification and responses to oestradiol and xeno-
estrogens. Exp Physiol 84:1013–1022.
Watson CS, Gametchu B. 2001. Membrane estrogen and gluco-
corticoid receptors—implications for hormonal control of
immune function and autoimmunity. Int Immunopharmacol
1:1049–1063.
Watson CS, Gametchu B. 2003. Proteins of multiple classes
may participate in nongenomic steroid actions. Exp Biol
Med (Maywood ) 228:1272–1281.
Welshons WV, Thayer KA, Judy BM, Taylor JA, Curran EM,
Vom Saal FS. 2003. Large effects from small exposures. I.
Mechanisms for endocrine-disrupting chemicals with
estrogenic activity. Environ Health Perspect 111:994–1006.
Wozniak AL, Bulayeva NN, Watson CS. 2005. Xenoestrogens at
picomolar to nanomolar concentrations trigger membrane
estrogen receptor-α-mediated Ca
2+
fluxes and prolactin
release in GH3/B6 pituitary tumor cells. Environ Health
Perspect 113:431–439.
Yunginger JW, Reed CE, O’Connell EJ, Melton LJ III,
O’Fallon WM, Silverstein MD. 1992. A community-based
study of the epidemiology of asthma. Incidence rates,
1964–1983. Am Rev Respir Dis 146:888–894.
Zaitsu M, Narita S, Lambert KC, Grady JJ, Estes DM, Curran EM,
et al. 2006. Estradiol activates mast cells via a non-genomic
estrogen receptor-α and calcium influx. Mol Immunol
doi:10.1016/j.molimm.2006.09.030 [Online 3 November 2006].
... However, the current literature often overlooks the potential influence of oestrogen on the female microbiota, despite previous studies revealing its impact [50][51][52]. There is also evidence that oestrogen affects mast cells [53,54]. A plausible pathomechanism implicated in IC/BPS centres on the overactivation of mast cells, subsequently stimulating unmyelinated C-fibres, and thereby triggering bladder pain and the release of neuropeptides. ...
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... Concerning mast cells, it has also been shown that an increase in the estrogenic environment promotes its degranulation and histamine release via Erα [73]. Indeed, estrogen reduces the activity of the enzyme diamine oxidase, which breaks down histamine and may contribute to the increase of its half-life [74]. ...
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Purpose of review Hormones such as estrogen, progesterone, and testosterone can contribute to differences in allergy prevalence and severity between men and women by affecting the immune system. This review aims to analyze what is currently known about the role of hormones as cofactors in food allergy. Recent findings Studies on rodents indicate immunological differences between males and females, with females generally exhibiting a more robust immune response. Estrogens are associated with enhanced humoral immunity and antibody synthesis, while androgens and progesterone suppress immunity and inflammation. Studies suggest that estrogens can exacerbate a pre-existing bias towards Th2 immune responses associated with atopy. Summary The complex relationship between the immune response and hormones significantly influences allergic disease outcomes, contributing to gender differences.
... Numerous hormonal changes occur during pregnancy, including increased secretion of estrogens and progesterone, with both hormones also having immunomodulatory effects [23]. In animal models, it has also been shown that estrogens can increase histamine release, so a possible pathogenetic effect on chronic urticaria has been suggested [28,29]. Data regarding the influence of sex hormones on acute urticaria, for example in terms of increased susceptibility, do not exist, but two clinical pictures have been described that may be associated with hormone-associated urticarial changes and should also be considered differentially in patients who are pregnant. ...
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... These cytokines bind to corresponding receptors on C-type sensory neurons leading to the sensation of itching [27]. In addition, estrogen is known to act, inter alia, on mast cells and induce IgE-mediated degranulation, reinforcing the stimulatory effect of this hormone on allergic diseases [28,29]. It is therefore believed that women with pruritus gravidarum develop the condition from having higher estrogen levels; a hypersensitivity to estrogen receptors; or an abnormal estrogen metabolism [23]. ...
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Background: Mast cells, by virtue of their location within the skin, respiratory tract, and gastrointestinal system, are considered as potential targets for environmental agents with immunotoxic effects. Mercuric chloride (HgCl2 ), is a xenobiotic, which induces autoimmune glomerulonephritis and stimulates polyclonal IgE production. Objective: We sought to determine the ability of HgCl2 to degranulate murine mast cells and promote cytokine secretion and whether this was an active biologic process. Methods: Bone marrow–derived murine mast cells were exposed to HgCl2 , and the release of N-acetyl-β-D-hexosaminidase and secretion of IL-4 and TNF-α were measured. Results: HgCl2 was found to directly activate murine mast cells to release the granule-associated enzyme N-acetyl-β-D-hexosaminidase and to secrete the proinflammatory cytokines IL-4 and TNF-α. Cytokine secretion occurred hours after exposure to HgCl2 and required transcription and protein synthesis. The secretion of cytokines mediated by HgCl2 was additive to that which followed FcϵRI-induced mast cell activation. The IL-4 secretion by mast cells occurred at concentrations of HgCl2 (10–6 mol/L to 10–5 mol/L) comparable with those required to induce upregulation of IgE production in experimental animals. Conclusion: These findings demonstrate that HgCl2 will directly activate mast cells, which is followed by degranulation and IL-4 and TNF-α synthesis and secretion. These findings are consistent with recognition of HgCl2 as a biologically important environmentally derived immunotoxic agent for mast cells. (J Allergy Clin Immunol 1999;103:1108-14.)
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Our laboratory has identified plasma membrane oestrogen receptors on a GH3/B6 rat pituitary tumour cell line and several sublines which produce rapid (within minutes), non-genomic responses to oestrogens. Oestrogen receptors have been identified by their binding to nine different antibodies (Abs) which together recognize at least seven epitopes on the oestrogen receptor-α. GH3/B6/F10 cells, a membrane oestrogen receptor-enriched subline, elevate intracellular calcium levels in response to 10 nM oestradiol. Prolactin release in these cells is triggered by both 1 pM and 1 nM oestradiol and diethylstilbestrol (DES). A membrane oestrogen receptor-α immunocyto-chemical signal rapidly disappears (at 3 min) and reappears (at 12-15 min) when 1 nM oestradiol, 10 nM diethylstilbestrol, or 10 nM nonylphenol is applied to the cells. This suggests that both oestrogens and xenoestrogens can utilize this alternative pathway for oestrogenic action. Xenoestrogens, which have so far shown weak effects in genomic assay systems, should now be retested for activity in eliciting membrane-initiated oestrogenic responses.
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Although nonclassical estrogen actions initiated at the cell surface have been described in many tissues, the identities of the membrane estrogen receptors (mERs) mediating these actions remain unclear. Here we show that GPR30, an orphan receptor unrelated to nuclear estrogen receptors, has all the binding and signaling characteristics of a mER. A high-affinity (dissociation constant 2.7 nm), limited capacity, displaceable, single binding site specific for estrogens was detected in plasma membranes of SKBR3 breast cancer cells that express GPR30 but lack nuclear estrogen receptors. Progesterone-induced increases and small interfering RNA-induced decreases in GPR30 expression in SKBR3 cells were accompanied by parallel changes in specific estradiol-17beta (E2) binding. Plasma membranes of human embryonic kidney 293 cells transfected with GPR30, but not those of untransfected cells, and human placental tissues that express GPR30 also displayed high-affinity, specific estrogen binding typical of mERs. E2 treatment of transfected cell membranes caused activation of a stimulatory G protein that is directly coupled to the receptor, indicating GPR30 is a G protein-coupled receptor (GPCR), and also increased adenylyl cyclase activity. The finding that the antiestrogens tamoxifen and ICI 182,780, and an environmental estrogen, ortho,para-dichlorodiphenyldichloroethylene (o,p'-DDE), have high binding affinities to the receptor and mimic the actions of E2 has important implications for both the development and treatment of estrogen-dependent breast cancer. GPR30 is structurally unrelated to the recently discovered family of GPCR-like membrane progestin receptors. The identification of a second distinct class of GPCR-like steroid membrane receptors suggests a widespread role for GPCRs in nonclassical steroid hormone actions.
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To determine whether the incidence of asthma had increased in Rochester, Minnesota, from January 1, 1964 through December 31, 1983, we used a population-based computer-linked medical diagnosis system to identify individual medical records with diagnosis of asthma or other conditions mimicking asthma. All records were reviewed using explicit predetermined diagnostic criteria; we identified 3,622 incident cases of asthma, including definite asthma (n = 1,547), probable asthma (n = 952), and single wheezing episodes (n = 1,123). The annual age- and sex-adjusted incidence of definite + probable asthma rose from 183 per 100,000 in 1964 to 284 per 100,000 in 1983. This rise was entirely accounted for by increased incidence rates in children and adolescents (age range, 1 to 14 yr); incidence rates for infants younger than 1 yr of age and for adults remained constant. For definite + probable asthma cases, the incidence rates for males were higher than for females from infancy through 9 yr of age and for persons older than 50; incidence rates for females were higher than for males from 15 through 49 yr of age. The median age at onset was 3 yr for males and 8 yr for females. We conclude that asthma begins in early childhood, with a higher incidence and earlier onset in males, and that the increase in incidence rates seen from 1964 to 1983 occurred only in children and in adolescents.
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A cell line showing many characteristics of immature mast cells has been established from the peripheral blood of a patient with mast cell leukemia. Cultured cells contain low levels of histamine, are stained metachromatically by toluidine blue, and contain chloroacetate esterase, aminocaproate esterase and tryptase activities. The cells lack T and B lymphocyte, as well as myeloid cell markers, and do not possess IgE receptors. Solid tumors of metachromatically positive cells have been successfully induced and serially passed in nude mice using 5-azacytidine transformed cells. This cell line may be useful for future studies of mast cells and their constituents.
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Inuit people (Eskimos) are likely exposed to persistent organochlorine compounds because their traditional diet includes fatty tissues of the arctic marine biota. Here we present the results of organochlorine compound analysis in milk fat samples from arctic Québec Inuit women and in fat tissues from various animal species inhabiting that region. The total concentration of polychlorinated biphenyl congeners in Inuit milk fat was similar to that of the beluga, while the profile of the 10 congeners resembled that of the polar bear. Mean concentrations of various organochlorines in milk-fat samples from Inuit women were between 2 and 10 times greater than those found in samples previously collected from southern Québec women. The Inuit mothers exhibit the greatest body burden known to occur from exposure to organochlorine residues present in the environment by virtue of their location at the highest trophic level of the arctic food web. Images p618-a