Estrogen augments the T cell-dependent but not the T-independent immune response

Sex-based difference in immune responses and efficacy of the pneumococcal conjugate vaccine

Vaccine-mediated protection and susceptibility to Streptococcus pneumoniae (pneumococcus) infections are influenced by biological sex. The incidence of invasive pneumococcal disease remains higher in males compared to females even after the introduction of the pneumococcal conjugate vaccine (PCV). However, sex-based differences in the immune response to this conjugate vaccine remain unexplored. To investigate those differences, we vaccinated adult male and female mice with PCV and assessed cellular and humoral immune responses. Compared to females, male mice displayed lower levels of T follicular helper cells, germinal center B cells and plasmablasts, which are all required for antibody production following vaccination. This was linked to lower IgG and IgM levels against pneumococci and lower isotype switching to IgG3 in vaccinated males. Due to lower antibody levels, sera of vaccinated male mice had lower efficacy in several anti-pneumococcal functions including neutralization of bacterial binding to pulmonary epithelial cells as well as direct cytotoxicity against S. pneumoniae. Importantly, while the vaccine was highly protective in females, vaccinated males succumbed to infection more readily and were more susceptible to both lung-localized infection and systemic spread following S. pneumoniae challenge. These findings identify sex-based differences in immune responses to PCV that can inform future vaccine strategies.

Sex-Dependent T Cell Dysregulation in Mice with Diet-Induced Obesity

Obesity is an emerging public health problem. Chronic low-grade inflammation is considered a major promotor of obesity-induced secondary diseases such as cardiovascular and fatty liver disease, type 2 diabetes mellitus, and several cancer entities. Most preliminary studies on obesity-induced immune responses have been conducted in male rodents. Sex-specific differences between men and women in obesity-induced immune dysregulation have not yet been fully outlined but are highly relevant to optimizing prevention strategies for overweight-associated complications. In this study, we fed C57BL/6 female vs. male mice with either standard chow or an obesity-inducing diet (OD). Blood and spleen immune cells were isolated and analyzed by flow cytometry. Lean control mice showed no sex bias in systemic and splenic immune cell composition, whereas the immune responses to obesity were significantly distinct between female and male mice. While immune cell alterations in male OD mice were characterized by a significant reduction in T cells and an increase in myeloid-derived suppressor cells (MDSC), female OD mice displayed preserved T cell numbers. The sex-dependent differences in obesity-induced T cell dysregulation were associated with varying susceptibility to body weight gain and fatty liver disease: Male mice showed significantly more hepatic inflammation and histopathological stigmata of fatty liver in comparison to female OD mice. Our findings indicate that sex impacts susceptibility to obesity-induced T cell dysregulation, which might explain sex-dependent different incidences in the development of obesity-associated secondary diseases. These results provide novel insights into the understanding of obesity-induced chronic inflammation from a sex-specific perspective. Given that most nutrition, exercise, and therapeutic recommendations for the prevention of obesity-associated comorbidities do not differentiate between men and women, the data of this study are clinically relevant and should be taken into consideration in future trials and treatment strategies.

Gender differences in measles incidence rates in a multi-year, pooled analysis, based on national data from seven high income countries

Background

Gender differences in a number of infectious diseases have been reported. The evidence for gender differences in clinical measles incidence rates has been variable and poorly documented over age groups, countries and time periods.

Methods

We obtained data on cases of measles by sex and age group over a period of 11–27 years from seven countries. Male to female incidence rate ratios (IRR) were computed for each year, by country and age group. For each age group, we used meta-analytic methods to combine the IRRs. Meta-regression was conducted to the estimate the effects of age, country, and time period on the IRR.

Results

In the age groups < 1, 1–4, 5–9, 10–14, 15–44, and 45–64 the pooled IRRs (with 95% CI) were 1.07 (1.02–1.11), 1.10 (1.07–1.14), 1.03 (1.00–1.05), 1.05 (0.99–1.11), 1.08 (0.95–1.23), and 0.82 (0.74–0.92) respectively. The excess incidence rates (IR) from measles in males up to age 45 are remarkably consistent across countries and time-periods. In the age group 45–64, there is an excess incidence in women.

Conclusions

The consistency of the excess incidence rates in young males suggest that the sex differences are more likely due to physiological and biological differences and not behavioral factors. At older ages, differential exposure can play a part. These findings can provide further keys to the understanding of mechanisms of infection and tailoring vaccination schedules.

The pharmacokinetics of PEGylated liposomal doxorubicin are not significantly affected by sex in rats or humans, but may be affected by immune dysfunction

PEGylated liposomal doxorubicin (PLD, Caelyx®, Doxil®) has been suggested to show significant sex-based differences in plasma clearance, as well as high inter-individual variability that may be driven by monocyte counts in cancer patients. This study aimed to establish if these differences are similarly observed in rats, which exhibit similar liposome clearance mechanisms to humans, and to use this model to identify sources of inter-individual and sex-based pharmacokinetic variability. The plasma and lymphatic pharmacokinetics of PLD were evaluated in male and female rats by quantifying doxorubicin as well as the ³H-labelled liposome. In general, the pharmacokinetics of doxorubicin and the ³H-liposome did not differ significantly between male and female rats when corrected for body surface area. Female rats did, however, show significantly higher doxorubicin concentrations in lymph compared to male rats. With the exception of serum testosterone concentrations in males, none of the physiological parameters evaluated correlated with plasma clearance. Further, reanalysis of published human data that formerly reported sex-differences in PLD plasma clearance similarly revealed no significant differences in PLD plasma clearance between males and females with solid tumours, but increased plasma clearance in patients with Kaposi's sarcoma (generally HIV+/immunocompromised). These data suggest that with the exception of lymphatic exposure, there are unlikely to be significant sex effects in the pharmacokinetics of liposomes, but immune function may contribute to inter individual variability.

Estrogen/ER in anti-tumor immunity regulation to tumor cell and tumor microenvironment

As the essential sexual hormone, estrogen and its receptor has been proved to participate in the regulation of autoimmunity diseases and anti-tumor immunity. The adjustment of tumor immunity is related to the interaction between cancer cells, immune cells and tumor microenvironment, all of which is considered as the potential target in estrogen-induced immune system regulation. However, the specific mechanism of estrogen-induced immunity is poorly understood. Typically, estrogen causes the nuclear localization of estrogen/estrogen receptor complex and alternates the transcription pattern of target genes, leading to the reprogramming of tumor cells and differentiation of immune cells. However, the estrogen-induced non-canonical signal pathway activation is also crucial to the rapid function of estrogen, such as NF-κB, MAPK-ERK, and β-catenin pathway activation, which has not been totally illuminated. So, the investigation of estrogen modulatory mechanisms in these two manners is vital for the tumor immunity and can provide the potential for endocrine hormone targeted cancer immunotherapy. Here, this review summarized the estrogen-induced canonical and non-canonical signal transduction pathway and aimed to focus on the relationship among estrogen and cancer immunity as well as immune-related tumor microenvironment regulation. Results from these preclinical researches elucidated that the estrogen-target therapy has the application prospect of cancer immunotherapy, which requires the further translational research of these treatment strategies.

Gender differences in food allergy depend on the PPAR γ/NF-κB in the intestines of mice

AIMS

Epidemiology shows that gender affects the incidence of food allergy. However, there is a lack of evidence of gender differences in food allergies and little is known about the mechanisms. The aim of this study was to excavate potential reasons for gender differences in food allergy based on estrogen.

MAIN METHODS

Female and male BALB/c mice sensitized with ovalbumin (OVA) were established to analyze the difference in food allergy. The systemic anaphylactic, including OVA-specific IgE, OVA-specific IgG, histamine, and cytokines, was assessed using an enzyme-linked immunosorbent assay (ELISA). ELISA also detected the estradiol in serum. Western blotting and immunofluorescence were used to detect the estrogen receptor. Peroxisome proliferator-activated receptor gamma (PPARγ) implicated in immune homeostasis and nuclear factor kappa-B (NF-κB) were determined by western blotting. Immunohistochemistry and hematoxylin-eosin (H&E) staining were used to detect zonula occludens-1 (ZO-1), tryptase, forkhead box protein P3 (Foxp3), and intestinal morphology, respectively.

KEY FINDINGS

Female mice were more vulnerable to food allergy. Female mice treated with OVA did exhibit more serious systemic anaphylaxis than male mice. We observed increased levels of estradiol in serum, estrogen receptor, NF-κB, and decreased levels of PPAR γ in female mice. Furthermore, the intestinal mucosal integrity and intestinal permeability were more impaired in female mice treated with OVA than male mice.

SIGNIFICANCE

Clarify the mechanism of gender differences in food allergies can provide targets in female mice and provide personalized diagnosis, management, and treatment of food allergy for female mice.

Effects of CD4+ T lymphocytes from ovariectomized mice on bone marrow mesenchymal stem cell proliferation and osteogenic differentiation

The present study was designed to investigate the effects of T cells on the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs). BMMSCs were co-cultured with CD4⁺ T cells that had been pretreated with anti-TNF-α or controls and were derived from ovariectomized (OVX) mice or sham control mice. MTT was used to assess the proliferative ability of BMMSCs and flow cytometry was used to analyze the BMMSC cell cycle. Following the induction of osteogenic differentiation in BMMSCs, calcium nodules were observed using alizarin red staining and alkaline phosphatase (ALP) staining. The expression levels of the osteogenesis-associated genes, runt related transcription factor 2 (Runx2) and osteocalcin (OCN) in BMMSCs were quantified using reverse transcription-quantitative PCR and western blotting. Osteogenesis-related signaling pathways, including ERK, JNK and p38 MAPK were also examined by western blotting. BMMSCs co-cultured with CD4⁺ T cells from OVX mice exhibited reduced proliferative ability compared with sham mice and the cell cycle was arrested at the G2/M phase. Additionally, BMMSCs co-cultured with CD4⁺ T cells from OVX mice presented with reduced levels of osteogenic differentiation and lower ALP activity, less calcium deposition and reduced expression of Runx2 and OCN compared with sham mice. The reduced levels of proliferation and osteogenic differentiation of BMMSCs induced by CD4⁺ T cells were not seen when the T cells were had been pretreated with anti-TNF-α. The results indicated that CD4⁺ T cells from OVX mice inhibited the proliferation and osteogenic differentiation of BMMSCs by producing high levels of TNF-α and may provide a novel insight into the dysfunction of BMMSCs caused by estrogen deficiency.

Synaptic plasticity in hippocampal CA1 neurons and learning behavior in acute kidney injury, and estradiol replacement in ovariectomized rats

Background

Neurological complications may occur in patients with acute or chronic renal failure; however, in cases of acute renal failure, the signs and symptoms are usually more pronounced, and progressed rapidly. Oxidative stress and nitric oxide in the hippocampus, following kidney injury may be involved in cognitive impairment in patients with uremia. Although many women continue taking hormone therapy for menopausal symptom relief, but there are also some controversies about the efficacy of exogenous sex hormones, especially estrogen therapy alone, in postmenopausal women with kidney injury. Herein, to the best of our knowledge for the first time, spatial memory and synaptic plasticity at the CA1 synapse of a uremic ovariectomized rat model of menopause was characterized by estradiol replacement alone.

Results

While estradiol replacement in ovariectomized rats without uremia, promotes synaptic plasticity, it has an impairing effect on spatial memory through hippocampal oxidative stress under uremic conditions, with no change on synaptic plasticity. It seems that exogenous estradiol potentiated the deleterious effect of acute kidney injury (AKI) with increasing hippocampal oxidative stress.

Conclusions

Although, estrogen may have some positive effects on cognitive function in healthy subjects, but its efficacy in menopause subjects under uremic states such as renal transplantation, needs to be further investigated in terms of dosage and duration.

β‑estradiol alleviates hypertension‑ and concanavalin A‑mediated inflammatory responses via modulation of connexins in peripheral blood lymphocytes

Gap junctions (GJs) formed by connexins (Cxs) in T lymphocytes have been reported to have important roles in the T lymphocyte-driven inflammatory response and hypertension-mediated inflammation. Estrogen has a protective effect on cardiovascular diseases, including hypertension and it attenuates excessive inflammatory responses in certain autoimmune diseases. However, the mechanisms involved in regulating the pro-inflammatory response are complex and poorly understood. The current study investigated whether β-estradiol suppresses hypertension and pro-inflammatory stimuli-mediated inflammatory responses by regulating Cxs and Cx-mediated GJs in peripheral blood lymphocytes. Male, 16-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) rats were randomly divided into the following three groups: WKY rats, vehicle (saline)-treated SHRs, and β-estradiol (20 µg/kg/day)-treated SHRs. β-estradiol was administered subcutaneously for 5 weeks. Hematoxylin and eosin staining was performed to evaluate target organ injury. Flow cytometry and ELISA were used to measure the populations of T lymphocyte subtypes in the peripheral blood, and expression of Cx40/Cx43 in T cell subtypes, and pro-inflammation cytokines levels, respectively. ELISA, a dye transfer technique, immunofluorescence and immunoblotting were used to analyze the effect of β-estradiol on pro-inflammatory cytokine secretion, Cx-mediated GJs and the expression of Cxs in concanavalin A (Con A)-stimulated peripheral blood lymphocytes isolated from WKY rat. β-estradiol significantly decreased blood pressure and inhibited hypertension-induced target organ injury in SHRs. Additionally, β-estradiol treatment significantly improved the immune homeostasis of SHRs, as demonstrated by the decreased percentage of cluster of differentiation (CD)4⁺/CD8⁺ T-cell subset ratio, reduced serum levels of pro-inflammatory cytokines and increased the percentage of CD4⁺CD25⁺ T cells. β-estradiol also markedly reduced the expression of Cx40/Cx43 in T lymphocytes from SHRs. In vitro, β-estradiol significantly suppressed the production of pro-inflammatory cytokines, reduced communication via Cx-mediated gap junctions and decreased the expression of Cx40/Cx43 in Con A-stimulated lymphocytes. These results indicate that β-estradiol attenuates inflammation and end organ damage in hypertension, which may be partially mediated via downregulated expression of Cxs and reduced function of Cx-mediated GJ.

Oestrogen differentially modulates lymphoid and myeloid cells of the European sea bass in vitro by specifically regulating their redox biology

Besides their obvious role in sex determination and reproduction, oestrogens display a prominent and complex immunomodulatory role across all vertebrates. To date, our knowledge on the oestrogenic immunomodulation in non-mammalian species is, however, scarce. In both teleosts and mammals, the direct immunomodulatory function of oestrogen is underscored by the presence of multiple oestrogen receptor subtypes in the various immune cells. For a better understanding of the regulatory processes, we investigated the oestrogen receptor expression in two major lymphoid organs of European sea bass: the head-kidney and the spleen. All oestrogen receptor subtypes, including nuclear and membrane oestrogen receptors, were present in both immune organs as well as in the isolated leucocytes. The same findings have been previously made for the thymus. To determine the oestrogen responsiveness of the different immune cell populations and to evaluate the importance of non-genomic and genomic pathways, we assessed the kinetics and the concentration dependent effects of 17β-oestradiol on isolated leucocytes from the head-kidney, the spleen and the thymus in vitro. Given the importance of reactive oxygen species as signalling and defence components in mammalian immune cells, the oxidative burst capacity, the redox status and the viability of both lymphoid and myeloid cells were measured by flow cytometry. The treatment with 17β-oestradiol specifically modulated these parameters depending on (1) the time kinetic, (2) the concentration of 17β-oestradiol, (3) the immune cell population (lymphoid and myeloid cells) as well as (4) the lymphoid organs from which they originated. The observed in vitro oestrogenic effects as well the presence of various oestrogen receptor subtypes in the immune cells of sea bass suggest a complex and direct oestrogenic action via multiple interconnected oestrogen-signalling pathways. Additionally, our study suggests that the oestrogenic regulation of the sea bass immune function involves a direct and tissue specific modulation of the immune cell redox biology comprising redox signalling, NADPH-oxidase activity and H₂O₂-permeability, thus changing oxidative burst capacity and immature T cell fate because oestrogen impacted thymocyte viability. Importantly, immune cells from both primary and secondary lymphoid organs have shown specific in vitro oestrogen-responsiveness. As established in mammals, oestrogen is likely to be specifically and directly involved in immature T cell differentiation and mature immunocompetent cell function in sea bass too.

Sex Differences in Older Adults' Immune Responses to Seasonal Influenza Vaccination

Background: Sex differences in immune responses to influenza vaccine may impact efficacy across populations. Methods: In a cohort of 138 older adults (50-74 years old), we measured influenza A/H1N1 antibody titers, B-cell ELISPOT response, PBMC transcriptomics, and PBMC cell compositions at 0, 3, and 28 days post-immunization with the 2010/11 seasonal inactivated influenza vaccine. Results: We identified higher B-cell ELISPOT responses in females than males. Potential mechanisms for sex effects were identified in four gene clusters related to T, NK, and B cells. Mediation analysis indicated that sex-dependent expression in T and NK cell genes can be partially attributed to higher CD4+ T cell and lower NK cell fractions in females. We identified strong sex effects in 135 B cell genes whose expression correlates with ELISPOT measures, and found that cell subset differences did not explain the effect of sex on these genes' expression. Post-vaccination expression of these genes, however, mediated 41% of the sex effect on ELISPOT responses. Conclusions: These results improve our understanding of sexual dimorphism in immunity and influenza vaccine response.

Sex hormone-binding globulin provides a novel entry pathway for estradiol and influences subsequent signaling in lymphocytes via membrane receptor

The complex effects of estradiol on non-reproductive tissues/cells, including lymphoid tissues and immunocytes, have increasingly been explored. However, the role of sex hormone binding globulin (SHBG) in the regulation of these genomic and non-genomic actions of estradiol is controversial. Moreover, the expression of SHBG and its internalization by potential receptors, as well as the influence of SHBG on estradiol uptake and signaling in lymphocytes has remained unexplored. Here, we found that human and mouse T cells expressed SHBG intrinsically. In addition, B lymphoid cell lines as well as both primary B and T lymphocytes bound and internalized external SHBG, and the amount of plasma membrane-bound SHBG decreased in B cells of pregnant compared to non-pregnant women. As potential mediators of this process, SHBG receptor candidates expressed by lymphocytes were identified in silico, including estrogen receptor (ER) alpha. Furthermore, cell surface-bound SHBG was detected in close proximity to membrane ERs while highly colocalizing with lipid rafts. The SHBG-membrane ER interaction was found functional since SHBG promoted estradiol uptake by lymphocytes and subsequently influenced Erk1/2 phosphorylation. In conclusion, the SHBG-SHBG receptor-membrane ER complex participates in the rapid estradiol signaling in lymphocytes, and this pathway may be altered in B cells in pregnant women.

The Role of Interleukin-10 in Mediating the Effect of Immune Challenge on Mouse Gonadotropin-Releasing Hormone Neurons In Vivo

Immune challenge alters neural functioning via cytokine production. Inflammation has profound impact on the central regulation of fertility, but the mechanisms involved are not clearly defined. The anti-inflammatory cytokine interleukin (IL)-10 is responsible for balancing the immune response in the brain. To examine whether IL-10 has an effect on the function of the gonadotropin-releasing hormone (GnRH) neurons, we first examined the effect of immune responses with distinct cytokine profiles, such as the T cell-dependent (TD) and T cell-independent (TI) B-cell response. We investigated the effect of the TD and TI immune responses on ERK1/2 phosphorylation in GnRH neurons by administering fluorescein isothiocyanate/keyhole limpet hemocyanin (KLH-FITC) or dextran-FITC to female mice. Although dextran-FITC had no effect, KLH-FITC induced ERK1/2 phosphorylation in GnRH neurons after 6 d. KLH-FITC treatment increased the levels of IL-10 in the hypothalamus (HYP), but this treatment did not cause lymphocyte infiltration or an increase in the levels of proinflammatory cytokines. In IL-10 knock-out (KO) mice, KLH-FITC-induced ERK1/2 phosphorylation in the GnRH neurons was absent. We also showed that in IL-10 KO mice, the estrous cycle was disrupted. Perforated patch-clamp recordings from GnRH-GFP neurons, IL-10 immunohistochemistry, and in vitro experiments on acute brain slices revealed that IL-10 can directly alter GnRH neuron firing and induce ERK1/2 phosphorylation. These observations demonstrate that IL-10 plays a role in influencing signaling of GnRH neurons in the TD immune response. These results also provide the first evidence that IL-10 can directly alter the function of GnRH neurons and may help the maintenance of the integrity of the estrous cycle.

Guidance for the identification of endocrine disruptors in the context of Regulations (EU) No 528/2012 and (EC) No 1107/2009

This Guidance describes how to perform hazard identification for endocrine-disrupting properties by following the scientific criteria which are outlined in Commission Delegated Regulation (EU) 2017/2100 and Commission Regulation (EU) 2018/605 for biocidal products and plant protection products, respectively.

GPR54 deficiency reduces the Treg population and aggravates experimental autoimmune encephalomyelitis in mice

GPR54 is highly expressed in the central nervous system and plays a crucial role in pubertal development. However, GRP54 is also expressed in the immune system, implying possible immunoregulatory functions. Here we investigated the role of GPR54 in T cell and immune tolerance. GPR54 deficiency led to an enlarged thymus, an increased number of thymocytes, and altered thymic micro-architecture starting around puberty, indicating GPR54 function in T-cell development through its regulatory effect on the gonadal system. However, flow cytometry revealed a significant reduction in the peripheral regulatory T cell population and a moderate decrease in CD4 single-positive thymocytes in prepubertal Gpr54^-/- mice. These phenotypes were confirmed in chimeric mice with GPR54 deficient bone marrow-derived cells. In addition, we found elevated T cell activation in peripheral and thymic T cells in Gpr54^-/- mice. When intact mice were immunized with myelin oligodendrocyte glycoprotein, a more severe experimental autoimmune encephalomyelitis (EAE) developed in the Gpr54^-/- mice. Interestingly, aggravated EAE disease was also manifested in castrated and bone marrow chimeric Gpr54^-/- mice compared to the respective wild-type control, suggesting a defect in self-tolerance resulting from GPR54 deletion through a mechanism that bypassed sex hormones. These findings demonstrate a novel role for GPR54 in regulating self-tolerant immunity in a sex hormone independent manner.

Comparative Analysis of Zearalenone Effects on Thyroid Receptor Alpha (TRα) and Beta (TRβ) Expression in Rat Primary Cerebellar Cell Cultures

Thyroid receptors play an important role in postnatal brain development. Zearalenone (ZEN), a major mycotoxin of Fusarium fungi, is well known to cause serious health problems in animals and humans through various mechanisms, including the physiological pathways of thyroid hormone (TH). In the present study, we aimed to investigate the expression of thyroid receptors α (TRα) and β (TRβ) in primary cerebellar neurons in the presence or absence of glia and following ZEN treatment, using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot. Primary cerebellar granule cells were treated with low doses of ZEN (0.1 nM) in combination with physiologically relevant concentrations of l-thyroxine (T4), 3,3′,5-triiodo-l-thyronine (T3) and 17β-estradiol (E2). Expression levels of TRα and TRβ at mRNA and protein levels were slightly modified by ZEN administered alone; however, along with thyroid and steroid hormones, modelling the physiological conditions, expression levels of TRs varied highly depending on the given treatment. Gene expression levels were also highly modulated by the presence or absence of glial cells, with mostly contrasting effects. Our results demonstrate divergent transcriptional and translational mechanisms involved in the expression of TRs implied by ZEN and hormonal milieu, as well as culturing conditions.

Immunohistochemical expression of ER-α and PR in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer with multiple risk factors including exposure to ionising radiation. Oestrogens contribute to papillary carcinoma development by promoting cell proliferation and invasion of mutated epithelial follicular cells. The present study aimed to assess ER-α and PR expression in PTC and to correlate their expression with the clinicopathological parameters in this cancer. This study included 62 primary and six metastatic papillary thyroid carcinoma cases. Nineteen and 38.7% of primary PTC cases showed positive nuclear expression for ER and PR, respectively. Metastatic cases showed 66.7% positive ER expression and all were negative for PR. Oestrogen receptor expression showed significant higher positivity in metastatic compared to primary PTC (p = 0.02) and it was significantly associated with primary PTC associated with thyroiditis (p = .002). Progesterone receptor expression was significantly associated with old age in primary PTC (p = .003) and it showed significant coparallel expression with ER (p = .000). Oestrogen and progesterone receptors expressed in papillary thyroid carcinoma opening the door for further studies to verify if those patients could benefit from hormonal therapy. Oestrogen receptor seems to have a role in metastatic process of PTC as malignant cells express it in metastatic more than primary site. The presence of lymphocytes in the stroma may promote ER expression in adjacent PTC, necessitating further studies on PTC cases associated with Hashimoto thyroiditis to verify this assumed relationship.

The phytogestrogenic stilbenes, arachidin-1 and resveratrol, modulate regulatory T cell functions responsible for successful aging in aged ICR mice

CD4+CD25+ regulatory T cells (Tregs) are recognized as a distinctive T helper cell population which controls immunosuppression during the maintenance of immunological self-tolerance and immunohomeostasis. Sex steroids modulate fundamental immune functions, including immune cell development, differentiation and polarization, and facilitate specific immunophysiological microenvironments, such as pregnancy. The supplementation of exogenous phytoestrogens is beneficial to post-menopausal women. Stilbenes are a potent group of phytoestrogens, of which resveratrol (Res) is a well-known representative exhibiting a variety of immunomodulatory activities, including the attenuation of autoimmune diseases and boosting anti-tumor immunity. In the present study, arachidin-1 (Ara‑1) and Res, primary stilbenes, enriched in peanut sprouts as phytoalexins, were investigated for their immunomodulatory properties for successful aging. We found that similar to 17-β-estradiol (E2), Ara‑1 or Res significantly inhibited concanavalin A (ConA)-activated lymphoblastogenesis of cell repertories from splenic or thymic origins. However, these inhibitory effects were partially reversed by the E2 receptor blocker, tamoxifen. While the ratios of the CD4+CD25+ cell population of ConA-activated T cell repertories were not significantly altered, treatment with E2, Ara‑1 or Res led to an increase in the number of cytotoxic T-lymphocyte associated protein 4 (CTLA-4; also known as CD152)-positive cells and in the gene expression levels of CTLA-4, Forkhead box P3 (FoxP3), interleukin (IL)-10 and transforming growth factor-β (TGF-β). When low (L-S-PNT) and high (H-S-PNT) levels of stilbene-enriched peanut sprout-fortified diets were provided ad libitum to 12‑week-old ICR mice for 48 weeks, their circulating Treg populations were assessed following magnetic bead enrichment. The gene expression levels of CTLA-4 and TGF-β were significantly (P<0.05) elevated, as assessed by semi-quantitative RT-PCR. The findings of the present study support the beneficial roles of the phytoestrogenic stilbenes, Res and Ara‑1, in facilitating a successful aging immune status which may attribute to longevity.

Membrane lipid rafts and estrogenic signalling: a functional role in the modulation of cell homeostasis

It has become widely accepted that along with their ability to directly regulate gene expression, estrogens also influence cell signalling and cell function via rapid membrane-initiated events. Many of these signalling processes are dependent on estrogen receptors (ER) localized to the plasma membrane. However, the mechanisms by which ER are able to trigger cell signalling when targeted to the membrane surface have to be determined yet. Lipid rafts seem to be essential for the plasma membrane localization of ER and play a critical role in their membrane-initiated effects. In this review, we briefly recapitulate the localization and function of ER in different cell types and mostly discuss the possible role of lipid rafts in this context. Further studies in this field may disclose new promising therapeutic avenues by the disruption of lipid rafts in those diseases in which membrane ER activation has been demonstrated to play a pathogenetic role.

A dynamic network of estrogen receptors in murine lymphocytes: fine-tuning the immune response

The actual level of circulating estrogen (17β-estradiol, E2) has a serious impact on regulation of diverse immune cell functions, where their classical cytoplasmic receptors, ERα and ERβ, act as nuclear transcriptional regulators of multiple target genes. There is growing evidence, however, for rapid, "non-nuclear" regulatory effects of E2 on lymphocytes. Such effects are likely mediated by putative membrane-associated receptor(s) (mER), but the mechanistic details and the involved signaling pathways still remained largely unknown because of their complexity. Here, we show that in lymphocytes, mERs can signalize themselves, and upon ligation, they are able to coordinate translocation of other E2Rs to the PM. Our data firmly imply existence of a complex, dynamic network of at least seven ER forms in murine lymphocytes: cytoplasmic and membrane-linked forms of ERα, ERβ, or GPR30 and a mER that can receive extracellular E2 signals. The latter mERs are likely palmitoylated, as they are enriched in lipid-raft microdomains, and their E2 binding is also cholesterol dependent. The data also support that ligation of mERs can induce rapid regulatory signals to lymphocytes and then internalize and let the E2 liberate in lysosomes. In addition, they can dynamically control the cell-surface linkage of other cytoplasmic ERs. As demonstrated by the differential effects of mER or cytoplasmic ER ligation on the proliferation of activated T and B lymphocytes, such a dynamic E2R network can be considered as a tool to manage accommodation/fine-tuning of lymphocytes to rapidly changing hormone levels.

The cystic fibrosis gender gap: potential roles of estrogen

Cystic fibrosis (CF) is a complex, multi-system, autosomal recessive disease predominantly affecting Caucasians that leads to vigorous airway inflammation and chronic respiratory infection, commonly with Pseudomonas aeruginosa. A variety of factors significantly modify the progression and severity of CF lung disease and the timing of the resulting mortality. We summarize here data indicating that there is in CF a female disadvantage in survival and morbidity, called the "CF gender gap". Although controversy exists regarding the nature and relative importance of the various contributing mechanisms involved, gender affects the progression of CF disease with respect to lung infection, decline in pulmonary function and nutritional status. These interrelated factors in turn have a negative impact on survival. This review will emphasize the increasing evidence that suggest a role for the effects of gender, and particularly the female sex hormone estrogen, on infection, inflammation and transepithelial ion transport, all major determinants of CF lung disease. Future elucidation of the pathophysiology of hormonal aggravation of CF lung disease may pave the way for novel therapeutic interventions. This, combined with the magnitude of the gender gap in CF mortality, strongly suggests that further work in this field is well justified.

Zearalenone, an estrogenic mycotoxin, is an immunotoxic compound

The aim of this study was to assess the toxic effects of zearalenone (ZEA) on the immune function. Ovariectomised rats were treated daily by gavage with 3.0 mg/kg of ZEA for 28 days. Body weight gain, food consumption, haemotological parameters, lymphoid organs, and their cellularities were evaluated. Moreover, acquired immune responses and macrophage activity were also assessed. ZEA promoted reduction in body weight gain, which is not fully explained by diminished food consumption. Despite no effect on haematological parameters, ZEA caused thymic atrophy with histological and thymocyte phenotype changes and decrease in the B cell percentage in the spleen. With respect to acquired and innate immune responses, no statistically significant differences in delayed-type hypersensitivity were noticed; however, in the ZEA-treated rats, antibody production and peroxide release by macrophages were impaired. The observed results could be related to ZEA activity on ERs; thus, ZEA is an immunotoxic compound similar to estrogen and some endocrine disruptors.

Integrating multiple oestrogen receptor alpha ChIP studies: overlap with disease susceptibility regions, DNase I hypersensitivity peaks and gene expression

BACKGROUND

A wealth of nuclear receptor binding data has been generated by the application of chromatin immunoprecipitation (ChIP) techniques. However, there have been relatively few attempts to apply these datasets to human complex disease or traits.

METHODS

We integrated multiple oestrogen receptor alpha (ESR1) ChIP datasets in the Genomic Hyperbrowser. We analysed these datasets for overlap with DNase I hypersensitivity peaks, differentially expressed genes with estradiol treatment and regions near single nucleotide polymorphisms associated with sex-related diseases and traits. We used FIMO to scan ESR1 binding sites for classical ESR1 binding motifs drawn from the JASPAR database.

RESULTS

We found that binding sites present in multiple datasets were enriched for classical ESR1 binding motifs, DNase I hypersensitivity peaks and differentially expressed genes after estradiol treatment compared with those present in only few datasets. There was significant enrichment of ESR1 binding present in multiple datasets near genomic regions associated with breast cancer (7.45-fold, p = 0.001), height (2.45-fold, p = 0.002), multiple sclerosis (5.97-fold, p < 0.0002) and prostate cancer (4.47-fold, p = 0.0008), and suggestive evidence of ESR1 enrichment for regions associated with coronary artery disease, ovarian cancer, Parkinson's disease, polycystic ovarian syndrome and testicular cancer. Integration of multiple cell line ESR1 ChIP datasets also increases overlap with ESR1 ChIP-seq peaks from primary cancer samples, further supporting this approach as helpful in identifying true positive ESR1 binding sites in cell line systems.

CONCLUSIONS

Our study suggests that integration of multiple ChIP datasets can highlight binding sites likely to be of particular biological importance and can provide important insights into understanding human health and disease. However, it also highlights the high number of likely false positive binding sites in ChIP datasets drawn from cell lines and illustrates the importance of considering multiple independent experiments together.

Humoral immune responses are maintained with age in a long-lived ectotherm, the red-eared slider turtle

Aging is typically associated with a decrease in immune function. However, aging does not affect each branch of the immune system equally. Because of these varying effects of age on immune responses, aging could affect taxa differently based on how the particular taxon employs its resources towards different components of immune defense. An example of this is found in the humoral immune system. Specific responses tend to decrease with age while non-specific, natural antibody responses increase with age. Compared with mammals, reptiles of all ages have a slower and less robust humoral immune system. Therefore, they may invest more in non-specific responses and thus avoid the negative consequences of age on the immune system. We examined how the humoral immune system of reptiles is affected by aging and investigated the roles of non-specific, natural antibody responses and specific responses by examining several characteristics of antibodies against lipopolysaccharide (LPS) in the red-eared slider turtle. We found very little evidence of immunosenescence in the humoral immune system of the red-eared slider turtle, Trachemys scripta, which supports the idea that non-specific, natural antibody responses are an important line of defense in reptiles. Overall, this demonstrates that a taxon's immune strategy can influence how the immune system is affected by age.

Specific and non-overlapping functions of testosterone and 11-ketotestosterone in the regulation of professional phagocyte responses in the teleost fish gilthead seabream

Sex hormones, both estrogens and androgens, have a strong impact on immunity in mammals. In fish, the role of androgens in immunity has received little attention and contradictory conclusions have been obtained. However, it is well known that sex steroids are involved in fish growth, osmoregulation and gonad remodelation. In this study, we examine the in vitro effects of testosterone and 11-ketotestosterone, the two main fish androgens, on the professional phagocytes of the teleost fish gilthead seabream (Sparus aurata L.). Although both testosterone and 11-ketotestosterone failed to modulate the respiratory burst of seabream phagocytes, testosterone but not 11-ketotestosterone was able to increase the phagocytic ability of non-activated phagocytes. Curiously, 11-ketotestosterone was more powerful than testosterone at inducing the expression of its own receptor, namely androgen receptor b (ARb), in acidophilic granulocytes (AGs), but none of them affected the basal ARb expression levels in macrophages (MØ). Furthermore, although physiological concentrations of testosterone exerted a pro-inflammatory effect on both AGs and MØs, 11-ketotestosterone showed an anti-inflammatory effect in AGs and a strong pro-inflammatory effect in MØs. Interestingly, both androgens modulated the expression of toll-like receptors in these two immune cell types, suggesting that androgens might regulate the sensitivity of phagocytes to pathogens and damage signals. Testosterone and 11-ketotestosterone have a competitive effect, at least, on the modulation of the expression of some genes. Therefore, our results show for the first time a non-overlapping role for testosterone and 11-ketotestosterone in the regulation of professional phagocyte functions in fish.

Sex-hormone receptors pattern on regulatory T-cells: clinical implications for multiple sclerosis

Cellular mechanisms underlying sexual dimorphism in the immune response remain largely unknown. Concerning the interactions among the nervous, endocrine and immune systems, we reported that during gestation, a period during which multiple sclerosis (MS) clearly ameliorates, there is a physiological expansion of regulatory T-lymphocytes (T(Reg)). Given that alterations in T(Reg) proportions and suppressive function are involved in MS pathophysiology, we investigated the in vitro effect of sex hormones on T(Reg). Here, we show that both E2 and progesterone (P2) enhance T(Reg) function in vitro, although only E2 further induces a T(Reg) phenotype in activated responder T-cells (CD4(+)CD25(-)) (P < 0.01). E2 receptor beta (ERβ) percentages and mean fluorescence intensity (MFI) on T(Reg) were lower in MS patients than in controls (P < 0.05), in parallel with lower E2 plasma levels (P < 0.05). Importantly, percentages and MFI of ERβ were higher in T(Reg) than in T-responder cells (P < 0.0001) both in MS patients and controls. We show a unique differential pattern of higher ER and PR levels in T(Reg), which may be relevant for the in vivo responsiveness of these cells to sex hormones and hence to MS physiopathology.

Estrogen aggravates inflammation in Pseudomonas aeruginosa pneumonia in cystic fibrosis mice

BACKGROUND

Among patients with cystic fibrosis (CF), females have worse pulmonary function and survival than males, primarily due to chronic lung inflammation and infection with Pseudomonas aeruginosa (P. aeruginosa). A role for gender hormones in the causation of the CF "gender gap" has been proposed. The female gender hormone 17β-estradiol (E2) plays a complex immunomodulatory role in humans and in animal models of disease, suppressing inflammation in some situations while enhancing it in others. Helper T-cells were long thought to belong exclusively to either T helper type 1 (Th1) or type 2 (Th2) lineages. However, a distinct lineage named Th17 is now recognized that is induced by interleukin (IL)-23 to produce IL-17 and other pro-inflammatory Th17 effector molecules. Recent evidence suggests a central role for the IL-23/IL-17 pathway in the pathogenesis of CF lung inflammation. We used a mouse model to test the hypothesis that E2 aggravates the CF lung inflammation that occurs in response to airway infection with P. aeruginosa by a Th17-mediated mechanism.

RESULTS

Exogenous E2 caused adult male CF mice with pneumonia due to a mucoid CF clinical isolate, the P. aeruginosa strain PA508 (PA508), to develop more severe manifestations of inflammation in both lung tissue and in bronchial alveolar lavage (BAL) fluid, with increased total white blood cell counts and differential and absolute cell counts of polymorphonuclear leukocytes (neutrophils). Inflammatory infiltrates and mucin production were increased on histology. Increased lung tissue mRNA levels for IL-23 and IL-17 were accompanied by elevated protein levels of Th17-associated pro-inflammatory mediators in BAL fluid. The burden of PA508 bacteria was increased in lung tissue homogenate and in BAL fluid, and there was a virtual elimination in lung tissue of mRNA for lactoferrin, an antimicrobial peptide active against P. aeruginosa in vitro.

CONCLUSIONS

Our data show that E2 increases the severity of PA508 pneumonia in adult CF male mice, and suggest two potential mechanisms: enhancement of Th17-regulated inflammation and suppression of innate antibacterial defences. Although this animal model does not recapitulate all aspects of human CF lung disease, our present findings argue for further investigation of the effects of E2 on inflammation and infection with P. aeruginosa in the CF lung.