The multi-faceted influences of estrogen on lymphocytes: toward novel immuno-interventions strategies for autoimmunity management

[Sex-specific differences of special tumor diseases]

BACKGROUND

Numerous data show that sex and gender have gained increasing importance in precision medicine as relevant modulators of specific oncological and hematological diseases. The purpose of this article is to provide a summary of the current state of knowledge on sex differences in the incidence and outcome of specific malignancies and to further elucidate possible underlying causes.

MATERIAL AND METHODS

Evaluation and discussion of basic research studies, meta-analyses, and clinical trials.

RESULTS

There are significant sex-specific differences in the incidence, response rates, and mortality for a variety of oncological diseases. For the most part, men have poorer outcomes, whereas women have higher treatment-associated toxicities and distinct presentations at younger ages. Hormonal, immunological, and pharmacological causes are suspected.

CONCLUSION

Advanced patient-individualized treatment in oncology and hematology will be measured in the future by the implementation of the existing relevant sex differences in the clinical practice and further investigations on underlying mechanisms in studies in order to guarantee and to optimize the best possible treatment for oncological patients in the future.

Effects of Hormone Therapy and Flavonoids Capable on Reversal of Menopausal Immune Senescence

Menopause, probably the most important natural change in a woman’s life and a major component of female senescence, is characterized, inter alia, by cessation of ovarian estrogen and progesterone production, resulting in a gradual deterioration of the female immune system. Hormone replacement therapy (HRT) is used in postmenopausal women to relieve some of the peri- and postmenopausal symptoms, while there is also evidence that the therapy may additionally partially reverse menopausal immune senescence. Flavonoids, and especially isoflavones, are widely used for the treatment of menopausal symptoms, although it is not at present clear whether they can reverse or alleviate other menopausal changes. HRT reverses the menopausal CD4/CD8 ratio and also limits the general peri- and postmenopausal inflammatory state. Moreover, the increased levels of interleukins (IL)-1β, IL-6, and IL-8, as well as of tumor necrosis factor-α (TNF-α) are decreased after the initiation of HRT. However, some reports show no effect of HRT on IL-4, IL-10, and IL-12. It is thus evident that the molecular pathways connecting HRT and female immune senescence need to be clarified. Interestingly, recent studies have suggested that the anti-inflammatory properties of isoflavones possibly interact with inflammatory cytokines when applied in menopause treatments, thereby potentially reversing immune senescence. This narrative review presents the latest data on the effect of menopausal therapies, including administration of flavonoid-rich products, on age-associated immune senescence reversal with the aim of revealing possible directions for future research and treatment development.

Whole-exome sequencing reveals the major genetic factors contributing to neuromyelitis optica spectrum disorder in Chinese patients with aquaporin 4-IgG seropositivity

BACKGROUND AND OBJECTIVE

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease. Although genetic factors are involved in its pathogenesis, limited evidence is available in this area. The aim of the present study was to identify the major genetic factors contributing to NMOSD in Chinese patients with aquaporin 4 (AQP4)-IgG seropositivity.

METHODS

Whole-exome sequencing (WES) was performed on 228 Chinese NMOSD patients seropositive for AQP4-IgG and 1400 healthy controls in Guangzhou, South China. Human leukocyte antigen (HLA) sequencing was also utilized. Genotype model and haplotype, gene burden, and enrichment analyses were conducted.

RESULTS

A significant region of the HLA composition is on chromosome 6, and great variation was observed in DQB1, DQA2 and DQA1. HLA sequencing confirmed that the most significant allele was HLA-DQB1*05:02 (p < 0.01, odds ratio [OR] 3.73). The genotype model analysis revealed that HLA-DQB1*05:02 was significantly associated with NMOSD in the additive effect model and dominant effect model (p < 0.05). The proportion of haplotype "HLA-DQB1*05:02-DRB1*15:01" was significantly greater in the NMOSD patients than the controls, at 8.42% and 1.23%, respectively (p < 0.001, OR 7.39). The gene burden analysis demonstrated that loss-of-function mutations in NOP16 were more common in the NMOSD patients (11.84%) than the controls (5.71%; p < 0.001, OR 2.22). The IgG1-G390R variant was significantly more common in NMOSD, and the rate of the T allele was 0.605 in patients and 0.345 in the controls (p < 0.01, OR 2.92). The enrichment analysis indicated that most of the genetic factors were mainly correlated with nervous and immune processes.

CONCLUSIONS

Human leukocyte antigen is highly correlated with NMOSD. NOP16 and IgG1-G390R play important roles in disease susceptibility.

Safety and efficacy analysis of pembrolizumab dosing patterns in patients with advanced melanoma and non-small cell lung cancer

AIM

To evaluate the impact of discrepancy between prescribed and recommended fixed 200 mg dose (P-F discrepancy) on immune-related adverse events (irAEs) and treatment efficacy in patients with advanced melanoma and NSCLC.

METHODS

This retrospective study included 177 patients with advanced melanoma or non-small cell lung cancer (NSCLC) who received at least one cycle of single-agent pembrolizumab. We defined P-F discrepancy as the differences between prescribed pembrolizumab dose and 200 mg recommended dose, expressed in percentages. Our primary outcome was immune-related adverse events (irAEs), and our secondary outcomes included overall survival (OS) and progression free survival (PFS).

RESULTS

The median P-F discrepancy was -21.5%, with the 25th and 75th percentile at -32% and -5.0% respectively. ROC curve analyses did not show any optimal cutoffs to prognosticate irAEs (AUC = 0.558 for all patients) or cancer mortality (AUC = 0.583 for melanoma; AUC = 0.539 for NSCLC) in either cancer type. Separate multivariable Cox analyses suggested no statistically significant association between P-F discrepancy and overall survival in patients with melanoma (HR 1.012, 95%CI 0.987-1.038, P = 0.362) or NSCLC (HR 0.998, 95%CI 0.978-1.019, P = 0.876).

CONCLUSION

There was no optimal pembrolizumab cut-off point to predict irAEs or treatment efficacy. We supported the use of weight-based pembrolizumab dosing, given the potential cost-saving and no differences in terms of irAEs or treatment efficacy in patients with advanced melanoma or NSCLC. Future studies on province- or national-level would be important to validate our findings.

Lead alters intracellular protein signaling and suppresses pro-inflammatory activation in TLR4 and IFNR-stimulated murine RAW 264.7 cells, in vitro

Lead (Pb) is a persistent environmental pollutant that has a structure and charge similar to many ions, such as calcium, that are essential for normal cellular function. Pb may compete with calcium for protein binding sites and inhibit signaling pathways within the cell affecting many organ systems including the immune system. The aim of the current study was to assess whether the calcium/calmodulin pathway is a principal target of environmentally relevant Pb during pro-inflammatory activation in a RAW 264.7 macrophage cell line. RAW 264.7 cells were cultured with 5 μM Pb(NO₃)₂, LPS, rIFNγ, or LPS+rIFNγ for 12, 24, or 48 hr. Intracellular protein signaling and multiple functional endpoints were investigated to determine Pb-mediated effects on macrophage function. Western blot analysis revealed that Pb initially modulated nuclear localization of NFκB p65 and cytoplasmic phosphorylation of CaMKIV accompanied by increased phosphorylation of STAT1β at 24 hr. Macrophage proliferation was significantly decreased at 12 hr in the presence of Pb, while nitric oxide (NO) was significantly reduced at 12 and 24 hr. Cells cultured with Pb for 12, 24, or 48 hr exhibited altered cytokine levels after specific stimuli activation. Our findings are in agreement with previous reports suggesting that macrophage pro-inflammatory responses are significantly modulated by Pb. Further, Pb-induced phosphorylation of CaMKIV (pCaMKIV), observed in the present study, may be a contributing factor in metal-induced autophagy noted in our previous study with this same cell line.

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.

Predictors of immunotherapy-induced immune-related adverse events

Purpose

We aimed to elucidate predictive factors for the development of immune-related adverse events (iraes) in patients receiving immunotherapies for the management of advanced solid cancers.

Methods

This retrospective study involved all patients with histologically confirmed metastatic or inoperable melanoma, non-small-cell lung cancer, or renal cell carcinoma receiving immunotherapy at the Cancer Centre of Southeastern Ontario. The type and severity of iraes, as well as potential protective and exacerbating factors, were collected from patient charts.

Results

The study included 78 patients receiving ipilimumab (32%), nivolumab (33%), or pembrolizumab (35%). Melanoma, non-small-cell lung cancer, and renal cell carcinoma accounted for 70%, 22%, and 8% of the cancers in the study population. In 41 patients (53%) iraes developed, with multiple iraes developing in 12 patients (15%). In most patients (70%), the iraes were of severity grade 1 or 2. Female sex [adjusted odds ratio (or_adj): 0.094; 95% confidence interval (ci): 0.021 to 0.415; p = 0.002] and corticosteroid use before immunotherapy (or_adj: 0.143; 95% ci: 0.036 to 0.562; p = 0.005) were found to be associated with a protective effect against iraes. In contrast, a history of autoimmune disease (or_adj: 9.55; 95% ci: 1.34 to 68.22; p = 0.025), use of ctla-4 inhibitors (or_adj: 6.25; 95% ci: 1.61 to 24.25; p = 0.008), and poor kidney function of grade 3 or greater (or_adj: 10.66; 95% ci: 2.41 to 47.12; p = 0.025) were associated with a higher risk of developing iraes. A Hosmer-Lemeshow goodness-of-fit test demonstrated that the logistic regression model was effective at predicting the development of iraes (chi-square: 1.596; df = 7; p = 0.979).

Conclusions

Our study highlights several factors that affect the development of iraes in patients receiving immunotherapy. Although future studies are needed to validate the resulting model, findings from the study can help to guide risk stratification, monitoring, and management of iraes in patients given immunotherapy for advanced cancer.

Sex Hormones in Acquired Immunity and Autoimmune Disease

Women have stronger immune responses to infections and vaccination than men. Paradoxically, the stronger immune response comes at a steep price, which is the high incidence of autoimmune diseases in women. The reasons why women have stronger immunity and higher incidence of autoimmunity are not clear. Besides gender, sex hormones contribute to the development and activity of the immune system, accounting for differences in gender-related immune responses. Both innate and adaptive immune systems bear receptors for sex hormones and respond to hormonal cues. This review focuses on the role of sex hormones particularly estrogen, in the adaptive immune response, in health, and autoimmune disease with an emphasis on systemic lupus erythematosus.

The Natural Agonist of Estrogen Receptor β Silibinin Plays an Immunosuppressive Role Representing a Potential Therapeutic Tool in Rheumatoid Arthritis

Estrogens, in particular 17β-estradiol (E2), have a strong influence on the immune system and also affect pathological conditions such as autoimmune diseases. The biological effects of E2 are mediated by two intracellular receptors, i.e., estrogen receptor (ER)α and ERβ, which function as ligand-activated nuclear transcription factors producing genomic effects. Immune cells express both ERα and ERβ that play a complex role in modulating inflammation. Phytoestrogens display estrogen-like effects. Among them, silibinin, the major active constituent of silymarin extracted by the milk thistle (Silybum marianum), has been suggested to have an ERβ selective binding. Silibinin is known to have anti-inflammatory, hepatoprotective, and anticarcinogenic effects; however, the role of silibinin in modulating human immune responses and its impact on autoimmunity remains unclear. Aim of this study was to dissect the ability of the ERβ natural ligand silibinin to modulate T cell immunity, taking into account possible differences between females and males, and to define its possible role as therapeutic tool in immune-mediated diseases. To this purpose, female and age-matched male healthy subjects and patients with active rheumatoid arthritis (RA) were recruited. We evaluated the ability of silibinin to modulate ERβ expression in T lymphocytes and its effects on T cell functions (i.e., apoptosis, proliferation, and cytokine production). We also analyzed whether silibinin was able to modulate the expression of microRNA-155 (miR-155), which strongly contributes to the pathogenesis of RA driving aberrant activation of the immune system. We demonstrated that silibinin upregulated ERβ expression, induced apoptosis, inhibited proliferation, and reduced expression of the pro-inflammatory cytokines IL-17 and TNF-α, through ERβ binding, in T lymphocytes from female and male healthy donors. We obtained similar results in T lymphocytes from patients with active RA in term of apoptosis, proliferation, and cytokine production. In addition, we found that silibinin acted as an epigenetic modifier, down-modulating the expression of miR-155. In conclusion, our data demonstrated an immunosuppressive role of silibinin, supporting its application in the treatment of autoimmune diseases as drug, but also as dietary nutritional supplement, opening new perspective in the field of autoimmune disease management.

Peripheral Lymphocyte Subsets as a Marker of Parkinson's Disease in a Chinese Population

In this study, we conducted a clinical analysis of lymphocyte subtypes in 268 patients with Parkinson's disease (PD) to assess their clinical impact as a potential marker of advanced PD in Chinese patients. The participants comprised 268 sporadic PD patients and 268 healthy controls. The numbers of natural killer (NK) cells and CD3+, CD3+CD4+, CD3+CD8+, and CD19+ lymphocytes from peripheral blood were determined by immunostaining and flow cytometric analysis and the percentages of these CD+ T cells were calculated. The ratio of regulatory T (Treg)/helper T 17 (Th17) lymphocytes from 64 PD patients and 46 controls was determined by flow cytometric analysis. The results showed that the percentage of NK cells was higher in advanced PD patients than in controls (22.92% ± 10.08% versus 19.76% ± 10.09%, P = 0.006), while CD3+ T cells are decreased (62.93% ± 9.27% versus 65.75% ± 9.13%, P = 0.005). The percentage of CD19+ B cells in male patients was lower (P = 0.021) than in female patients, whereas NK cells were increased (P < 0.0001). The scores on the Unified Parkinson's Disease Rating Scale (UPDRS) and the Non-Motor Symptoms Scale in late-onset PD patients were significantly higher than those in early-onset patients (P = 0.024 and P = 0.007, respectively). The percentage of CD19+ B cells in patients with UPDRS scores >24 was lower than in those with scores <24 (10.17% ± 4.19% versus 12.22% ± 5.39%, P = 0.009). In addition, the Treg/Th17 ratio in female patients was higher than that in female controls (13.88 ± 6.32 versus 9.94 ± 4.06, P = 0.042). These results suggest that the percentages of NK cells, CD3+ T cells, and CD19+ B cells along with the Treg/Th17 ratio in peripheral blood may be used to predict the risk of PD in Chinese individuals and provide fresh avenues for novel diagnostic biomarkers and therapeutic designs.

Estrogens Promote the Production of Natural Neutralizing Antibodies in Fish through G Protein-Coupled Estrogen Receptor 1

Natural antibodies play crucial roles in pathogen elimination, B-cell survival and homeostasis, and inflammatory and autoimmune diseases. Although estrogens are able to regulate both innate and adaptive immune responses, their role in the production of natural antibodies is unknown. Here, we show that the dietary intake of the synthetic estradiol analog, 17α-ethinylestradiol (EE₂), one of the most potent pharmaceutical estrogens and intensively used in human therapeutics as a component of most oral contraceptives, regulates the abundance and proliferation of T and IgM⁺ B lymphocytes in the teleost fish gilthead seabream (Sparus aurata L.). Furthermore, for the first time in vertebrates, it is shown that estrogen signaling through G protein-coupled estrogen receptor 1 (GPER1) induces the production of polyreactive natural antibodies, which are able to crossreact with unrelated antigens and commensal and pathogenic bacteria. In addition, the serum from fish treated with EE₂ or the GPER1 agonist G1 shows higher complement-dependent bactericidal activity than that from non-treated specimens. These results demonstrate that estrogens and GPER1 are the key regulators of natural antibody production and pathogen clearance in fish, paving the way for future studies in other vertebrate classes.

Immunology of neuromyelitis optica during pregnancy

Anti–aquaporin-4 (AQP4) autoantibody plays a key role in the pathogenesis of neuromyelitis optica (NMO). Studies have shown increased relapse rates in patients with NMO during pregnancy and postpartum. High estrogen levels during pregnancy can increase activation-induced cytidine deaminase expression, which is responsible for immunoglobulin production. Additionally, sex hormones may influence antibody glycosylation, with effects on antibody function. Estrogen decreases apoptosis of self-reactive B cells, through upregulation of antiapoptotic molecules. Furthermore, high estrogen levels during pregnancy can boost B-cell activating factor and type 1 interferon (IFN) production, facilitating development of self-reactive peripheral B cells in association with increased disease activity. Elevated levels of estrogen during pregnancy decrease IFN-γ generation, which causes a shift toward T helper (Th) 2 immunity, thereby propagating NMO pathogenesis. Women with NMO have an elevated rate of pregnancy complications including miscarriage and preeclampsia, which are associated with increased Th17 cells and reduction of T-regulatory cells. These in turn can enhance inflammation in NMO. Increased regulatory natural killer cells (CD56⁻) during pregnancy can enhance Th2-mediated immunity, thereby increasing inflammation. In the placenta, trophoblasts express AQP4 antigen and are exposed to maternal blood containing anti-AQP4 antibodies. Animal models have shown that anti-AQP4 antibodies can bind to AQP4 antigen in placenta leading to complement deposition and placental necrosis. Reduction of regulatory complements has been associated with placental insufficiency, and it is unclear whether these are altered in NMO. Further studies are required to elucidate the specific mechanisms of disease worsening, as well as the increased rate of complications during pregnancy in women with NMO.

Impact of Estrogen Therapy on Lymphocyte Homeostasis and the Response to Seasonal Influenza Vaccine in Post-Menopausal Women

It is widely recognized that changes in levels of ovarian steroids modulate severity of autoimmune disease and immune function in young adult women. These observations suggest that the loss of ovarian steroids associated with menopause could affect the age-related decline in immune function, known as immune senescence. Therefore, in this study, we determined the impact of menopause and estrogen therapy (ET) on lymphocyte subset frequency as well as the immune response to seasonal influenza vaccine in three different groups: 1) young adult women (regular menstrual cycles, not on hormonal contraception); 2) post-menopausal (at least 2 years) women who are not receiving any form of hormone therapy (HT) and 3) post-menopausal hysterectomized women receiving ET. Although the numbers of circulating CD4 and CD20 B cells were reduced in the post-menopausal group receiving ET, we also detected a better preservation of naïve B cells, decreased CD4 T cell inflammatory cytokine production, and slightly lower circulating levels of the pro-inflammatory cytokine IL-6. Following vaccination, young adult women generated more robust antibody and T cell responses than both post-menopausal groups. Despite similar vaccine responses between the two post-menopausal groups, we observed a direct correlation between plasma 17β estradiol (E2) levels and fold increase in IgG titers within the ET group. These findings suggest that ET affects immune homeostasis and that higher plasma E2 levels may enhance humoral responses in post-menopausal women.

Environmental estrogen bisphenol A and autoimmunity

Over the past few years, there has been evidence of the increasing prevalence of autoimmune diseases. Autoimmune diseases consist of many complex disorders of unknown etiology resulting in immune responses to self-antigens. The immune system, and its function, is under complex and integrated control and its disruption can be triggered by multiple factors. Autoimmunity development is influenced by multiple factors and is thought to be a result of interactions between genetic and environmental factors. Here, we review the role of a specific environmental factor, bisphenol A (BPA), in the pathogenesis of autoimmune diseases. BPA belongs to the group of environmental estrogens that have been identified as risk factors involved in the development of autoimmune diseases.

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.

Sex, the aging immune system, and chronic disease

The immune systems of men and women differ in significant ways, especially after puberty. In particular, females are generally more prone to autoimmunity, but experience lower rates of infections and chronic inflammatory disease. Sex hormones, genes encoded on the sex chromosomes, and gender-specific behaviors likely contribute to these differences. The aging process is associated with changes in the composition and function of the immune system and these changes may occur at an accelerated rate in men as compared to women. Moreover, after the age of menopause, the incidence of chronic inflammatory disease in women approaches or exceeds that observed in males. At the same time, the incidence of autoimmunity in post-menopausal women is decreased or equivalent to the rates observed in similarly-aged men. Additional studies addressing the influence of sex on the pathogenesis of chronic and autoimmune diseases in the aged are warranted.

Prolactin and natural killer cells: evaluating the neuroendocrine-immune axis in women with primary infertility and recurrent spontaneous abortion

PROBLEM

An association between serum prolactin (PRL) and peripheral blood natural killer (NK) cells has been described in healthy women. We explored for the first time the PRL response to the thyrotrophin-releasing hormone (TRH) test and the association between PRL and NK cells in women with reproductive failure.

METHODS

A total of 130 women [31 primary infertility, 69 recurrent spontaneous abortion (RSA), and 30 fertile women] were evaluated by a TRH test to analyze the following: basal PRL (bPRL), peak-time PRL, PRL absolute and relative increase, decline-time PRL. Hyperprolactinaemia (HPRL) was defined as bPRL ≥15 ng/mL. NK cells were characterized by immunophenotyping.

RESULTS

Significantly higher bPRL levels were found in the infertile women than in controls. Both the infertile and the RSA women showed significantly elevated NK levels. bPRL levels correlated with NK cells in HPRL-infertile women.

CONCLUSIONS

In patients with HPRL, an association between NK cell and bPRL results. The dynamic test in the infertile women would help in the management of the pregnancy impairment.

Autoantibodies to estrogen receptors and their involvement in autoimmune diseases and cancer

The involvement of estrogens, which influence many physiologic processes, has been shown in the development or progression of several diseases including some cancers, most notably breast cancer, and autoimmune disorders. Estrogenic signal is transferred via estrogen receptors (ER) which have dual localization, predominantly intracellular but also in plasma membrane. The discovery of membrane-associated ER (mER) has greatly expanded our understanding of estrogen action; upon ligand binding, mER rapidly activate different signaling pathways inducing downstream transcription factors. Some target genes of the mER pathway may be activated independently of the intracellular ER. Additionally, intracellular ER action can be modulated by mER-initiated signaling. Most notably, the identification of autoantibodies reacting with ER (ERAB) and their possible pathogenic role in autoimmunity and cancer have opened a new path for the research in the estrogen-related receptor activity. In this review, we briefly recapitulate the localization and function of ER and mostly discuss the possible role of ERAB as novel potential prognostic and/or predictive tools in autoimmunity and cancer.

Sex-specific association of estrogen receptor 2 polymorphisms with hepatitis C virus infection outcomes in a high-risk Chinese Han population

Hepatitis C virus (HCV) has different clinical and biological characteristics in women versus men, which suggests the potential involvement of estrogen. Estrogen signaling is mediated by the estrogen receptor, and genetic variations in the estrogen receptor gene might affect the pathology of HCV infection. We performed logistic regression analysis to explore the associations between rs1256049, rs4986938 and rs944459 polymorphisms of the estrogen receptor 2 gene (ESR2) and HCV infection outcomes. The variant A allele of rs4986938 was associated with an increased HCV infection susceptibility in the males (additive model: adjusted OR=1.493, P=0.010) and a significantly reduced risk of HCV infection in the female subgroup (GA vs. GG: adjusted OR=0.710, P=0.012; dominant model: adjusted OR=0.686, P=0.004; additive model: adjusted OR=0.703, P=0.002). In addition, females carrying the rs4986938 AA genotype appeared to clear HCV spontaneously more readily (adjusted OR=0.237, P=0.011), and additive model analyses showed that each additional allele contributed a decreased risk of approximately 34% for HCV chronicity (adjusted OR=0.659, P=0.006). Furthermore, a significant multiplicative interaction between the combined rs1256049 and rs4986938 genotypes was found to decrease HCV infection risk (adjusted OR=0.583, P=3.000×10(-4)). The area under the curve, based on the model and including age, gender, HCV genotypes and the three SNPs, was significantly related to the clearance of HCV (P=0.003). We provide here the first report that rs4986938 in the ESR2 gene played a potential sex-specific role in the etiology of HCV infection in a high-risk Chinese Han population, suggesting that ESR2 is a candidate susceptibility gene for HCV infection and viral clearance.

Serine protease inhibition attenuates rIL-12-induced GZMA activity and proinflammatory events by modulating the Th2 profile from estrogen-treated mice

Estrogen has potent immunomodulatory effects on proinflammatory responses, which can be mediated by serine proteases. We now demonstrate that estrogen increased the extracellular expression and IL-12-induced activity of a critical member of serine protease family Granzyme A, which has been shown to possess a novel inflammatory persona. The inhibition of serine protease activity with inhibitor 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride significantly diminished enhanced production of proinflammatory interferon-γ, IL-1β, IL-1α, and Granzyme A activity even in the presence of a Th1-inducing cytokine, IL-12 from splenocytes from in vivo estrogen-treated mice. Inhibition of serine protease activity selectively promoted secretion of Th2-specific IL-4, nuclear phosphorylated STAT6A, signal transducer and activator of transcription (STAT)6A translocation, and STAT6A DNA binding in IL-12-stimulated splenocytes from estrogen-treated mice. Inhibition with 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride reversed the down-regulation of Th2 transcription factors, GATA3 and c-Maf in splenocytes from estrogen-exposed mice. Although serine protease inactivation enhanced the expression of Th2-polarizing factors, it did not reverse estrogen-modulated decrease of phosphorylated STAT5, a key factor in Th2 development. Collectively, data suggest that serine protease inactivity augments the skew toward a Th2-like profile while down-regulating IL-12-induced proinflammatory Th1 biomolecules upon in vivo estrogen exposure, which implies serine proteases as potential regulators of inflammation. Thus, these studies may provide a potential mechanism underlying the immunomodulatory effect of estrogen and insight into new therapeutic strategies for proinflammatory and female-predominant autoimmune diseases.

Associations of IFN-γ rs2430561 T/A, IL28B rs12979860 C/T and ERα rs2077647 T/C polymorphisms with outcomes of hepatitis B virus infection: a meta-analysis

Several studies investigated associations of IFN-γ rs2430561 T/A, IL28B rs12979860 C/T and ERα rs2077647 T/C gene polymorphisms with outcomes of hepatitis B virus (HBV) infection, but the results were controversial. Therefore, we performed a meta-analysis of all published observational studies to address this inconsistency. Literature was searched in online database and a systematic review was conducted based on the search results. A total of 24 studies were included and dichotomous data were presented as odds ratio (OR) with a 95% confidence interval (CI). The rs2430561 T allele was associated with reduced persistent HBV infection risk (T vs. A: OR, 0.690; 95% CI, [0.490, 0.971]), while the rs2077647 T allele significantly increased the risk of persistent HBV infection (T vs. C: OR, 1.678; 95% CI, [1.212, 2.323]). Rs 2077647 CC might play a role in protecting individuals against HBV persistence (TT vs. CC: OR, 4.109; 95% CI, [2.609, 6.473]). Furthermore, carriers of the rs2430561 TT genotype were more likely to clear HBV spontaneously compared with those of the AA genotype (TT vs. AA: OR, 0.555; 95% CI, [0.359, 0.856]). For rs12979860 C/T polymorphism, no significant correlation with HBV infection outcomes was found. In subgroup analyses, the results were similar to those of overall analysis. However, for rs2077647 TT vs. TC+CC, significantly increased risks were observed in the Asian and hospital-based population, but not in the overall analysis. IFN-γ rs2430561 T/A and ERα rs2077647 T/C genetic polymorphisms were associated with outcomes of HBV infection, but no association was found between IL28B rs12979860 C/T and HBV infection.

Epigenetic regulation of cytokine expression in systemic lupus erythematosus with special focus on T cells

Epigenetic events play a central role in the priming, differentiation and subset determination of T lymphocytes. Through their influence on chromatin conformation and DNA-accessibility to transcription factors and RNA polymerases, epigenetic marks allow or prevent gene expression and control cellular functions including cytokine expression. CpG-DNA methylation and post-translational modifications to histone tails are the two most well accepted epigenetic mechanisms. The involvement of epigenetic mechanisms in the pathogenesis of systemic lupus erythematosus (SLE) has been suggested by the development of lupus-like symptoms by individuals who received procainamide or hydralazine treatment resulting in a reduction of CpG-DNA methylation. To date, a growing body of literature indicates that the deregulation of cytokine expression through epigenetic disturbances can result in altered immune responses and autoimmune reactions. Over the past decade, various global and regional epigenetic alterations have been reported in immune cells from patients with SLE and other autoimmune disorders. More recently, the molecular mechanisms that result in epigenetic disturbances have been addressed, and deregulated transcription factor networks have been demonstrated to mediate epigenetic alterations in B and T lymphocytes from SLE patients. A better understanding of the molecular events that contribute to epigenetic alterations and subsequent immune imbalance is essential for the establishment of disease biomarkers and identification of potential therapeutic targets.

The dopaminergic system in autoimmune diseases

Bidirectional interactions between the immune and the nervous systems are of considerable interest both for deciphering their functioning and for designing novel therapeutic strategies. The past decade has brought a burst of insights into the molecular mechanisms involved in neuroimmune communications mediated by dopamine. Studies of dendritic cells (DCs) revealed that they express the whole machinery to synthesize and store dopamine, which may act in an autocrine manner to stimulate dopamine receptors (DARs). Depending on specific DARs stimulated on DCs and T cells, dopamine may differentially favor CD4⁺ T cell differentiation into Th1 or Th17 inflammatory cells. Regulatory T cells can also release high amounts of dopamine that acts in an autocrine DAR-mediated manner to inhibit their suppressive activity. These dopaminergic regulations could represent a driving force during autoimmunity. Indeed, dopamine levels are altered in the brain of mouse models of multiple sclerosis (MS) and lupus, and in inflamed tissues of patients with inflammatory bowel diseases or rheumatoid arthritis (RA). The distorted expression of DARs in peripheral lymphocytes of lupus and MS patients also supports the importance of dopaminergic regulations in autoimmunity. Moreover, dopamine analogs had beneficial therapeutic effects in animal models, and in patients with lupus or RA. We propose models that may underlie key roles of dopamine and its receptors in autoimmune diseases.

Association of genetic variants in estrogen receptor α with HCV infection susceptibility and viral clearance in a high-risk Chinese population

The purpose of this study was to test the hypothesis that genetic variants of estrogen receptor α (ERα) are associated with the outcomes of hepatitis C virus (HCV) infection. We genotyped the seven single nucleotide polymorphisms (SNPs) (rs2077647, rs9340799, rs2234693, rs1801132, rs9322354, rs2228480 and rs3798577) of ERα and conducted a case-control study in a high-risk Chinese population, including 429 HCV spontaneous clearance cases, 880 persistent infection cases and 1,174 uninfected controls. The C allele of rs2234693 was significantly associated with increased susceptibility to HCV infection [dominant model: adjusted odds ratio (OR) = 1.377, 95% confidence interval (CI) =1.126-1.778], and the risk effect remained significant among the younger (≤55 years) and hemodialysis subjects (all P < 0.007). The other three SNPs variant genotypes also showed significant correlation with elevated risk of HCV infection in different strata (rs2077647 in males; rs9340799 in blood donors; rs1801132 in younger subjects; all P < 0.007). It was also discovered that carriage of rs2228480 A allele was more prone to develop persistent HCV infection (dominant model: adjusted OR = 1.203, 95% CI = 1.154-1.552), and the risk effect was more evident in females and blood donors (all P < 0.007). Haplotype analyses (rs2077647, rs9340799 and rs2234693) showed that, compared with the most frequent haplotype TAT, CAC played a risk effect in subgroups of younger (P = 3.24 × 10(-3)) and male (P = 5.51 × 10(-4)), whereas CAT expressed a protective effect in females (P = 2.27 × 10(-4)) for HCV infection susceptibility. We first report that these SNPs (rs2077647, rs9340799, rs2234693, rs1801132 and rs2228480) in ERα can influence the outcomes of HCV infection in a high-risk Chinese population.

Autoantibodies to estrogen receptor α in systemic sclerosis (SSc) as pathogenetic determinants and markers of progression

Systemic sclerosis (SSc) is a multisystem autoimmune disease of unknown etiology characterized by inflammation, autoantibody production, and fibrosis. It predominantly affects women, this suggesting that female sex hormones such as estrogens may play a role in disease pathogenesis. However, up to date, the role of estrogens in SSc has been scarcely explored. The activity of estrogens is mediated either by transcription activity of the intracellular estrogen receptors (ER), ERα and ERβ, or by membrane-associated ER. Since the presence of autoantibodies to ERα and their role as estrogen agonists interfering with T lymphocyte homeostasis were demonstrated in other autoimmune diseases, we wanted to ascertain whether anti-ERα antibodies were detectable in sera from patients with SSc. We detected anti-ERα antibody serum immunoreactivity in 42% of patients with SSc (30 out of 71 analyzed). Importantly, a significant association was found between anti-ERα antibody values and key clinical parameters of disease activity and severity. Fittingly, anti-ERα antibody levels were also significantly associated with alterations of immunological features of SSc patients, including increased T cell apoptotic susceptibility and changes in T regulatory cells (Treg) homeostasis. In particular, the percentage of activated Treg (CD4⁺CD45RA⁻ FoxP3^brightCD25^bright) was significantly higher in anti-ERα antibody positive patients than in anti-ERα antibody negative patients. Taken together our data clearly indicate that anti-ERα antibodies, probably via the involvement of membrane-associated ER, can represent: i) promising markers for SSc progression but, also, ii) functional modulators of the SSc patients’ immune system.

Parabens: potential impact of low-affinity estrogen receptor binding chemicals on human health

Parabens, alkyl esters of p-hydroxybenzoic acid, are widely used in cosmetics, pharmaceuticals, personal care products and as food additives to inhibit microbial growth and extend product shelf life. Consumers of these compounds are frequently exposed via the skin, lips, eyes, oral mucosa, nails, and hair. Parabens are estrogenic molecules but exert weaker activity than natural estrogens, which would imply a low risk. Consistent with this idea, a number of recent commission reports from different countries suggested that parabens pose a negligible endocrine-disrupting risk at the recommended doses. However, individuals are not routinely exposed to a single paraben, and most of the available paraben toxicity data, reviewed in these reports, are from single-exposure studies. Further, assessing the additive and cumulative risk of multiple paraben exposure from daily use of multiple cosmetic and/or personal care products is presently not possible based on current studies. In this review, current and recent studies of paraben exposure and public health policies as well as critical gaps in the knowledge are discussed and new research directions regarding multiple exposures and novel target cohorts are recommended.

Gender differences in cancer susceptibility: an inadequately addressed issue

The gender difference in cancer susceptibility is one of the most consistent findings in cancer epidemiology. Hematologic malignancies are generally more common in males and this can be generalized to most other cancers. Similar gender differences in non-malignant diseases including autoimmunity, are attributed to hormonal or behavioral differences. Even in early childhood, however, where these differences would not apply, there are differences in cancer incidence between males and females. In childhood, few cancers are more common in females, but overall, males have higher susceptibility. In Hodgkin lymphoma, the gender ratio reverses toward adolescence. The pattern that autoimmune disorders are more common in females, but cancer and infections in males suggests that the known differences in immunity may be responsible for this dichotomy. Besides immune surveillance, genome surveillance mechanisms also differ in efficiency between males and females. Other obvious differences include hormonal ones and the number of X chromosomes. Some of the differences may even originate from exposures during prenatal development. This review will summarize well-documented examples of gender effect in cancer susceptibility, discuss methodological issues in exploration of gender differences, and present documented or speculated mechanisms. The gender differential in susceptibility can give important clues for the etiology of cancers and should be examined in all genetic and non-genetic association studies.

Distorted expression of dopamine receptor genes in systemic lupus erythematosus

Several observations suggest that alterations in the neurotransmitter dopamine and/or its receptors could be associated with the pathophysiology of lupus. We therefore assessed expression of the five dopamine receptor genes in a cohort of patients. We found that all receptors are expressed in lupus peripheral blood cells. We also discovered that dopamine receptor 2 gene (DR2) was underexpressed, and that DR4 was overexpressed in lupus patients, as compared to controls. Cell sorting of peripheral T- and B-lymphocytes disclosed that the altered DR2 and DR4 expressions were borne by T-cells. These distorted expressions of DR2 and DR4 could influence immune functions in lupus through several mechanisms. Since DR2 can be effective in regulating the activation and differentiation of naive CD4⁺ cells by promoting polarization toward regulatory T-cells, the underexpression of DR2 we have observed may account, at least in part, for the reduction of regulatory T-cell function and/or numbers in lupus. In addition to providing novel insight into disease pathogenesis, our findings may have therapeutic implications. Because DR4 can be effective in triggering T-cell quiescence, its overexpression on lupus T cells suggests that inducing quiescence using DR4-specific agonists may represent a useful strategy in the treatment of lupus.

Menstrual and reproductive factors, and hormonal contraception use: associations with non-Hodgkin lymphoma in a pooled analysis of InterLymph case-control studies

BACKGROUND

The two most common forms of non-Hodgkin lymphoma (NHL) exhibit different sex ratios: diffuse large B-cell lymphoma (DLBCL) occurs more frequently in men and follicular lymphoma (FL) more frequently in women. Looking among women alone, this pooled analysis explores the relationship between reproductive histories and these cancers.

MATERIALS AND METHODS

Self-reported reproductive histories from 4263 women with NHL and 5971 women without NHL were pooled across 18 case-control studies (1983-2005) from North America, Europe and Japan. Study-specific odd ratios (ORs) and confidence intervals (CIs) were estimated using logistic regression and pooled using random-effects meta-analyses.

RESULTS

Associations with reproductive factors were found for FL rather than NHL overall and DLBCL. In particular, the risk of FL decreased with increasing number of pregnancies (pooled OR(trend) = 0.88, 95% CI 0.81-0.96). FL was associated with hormonal contraception (pooled OR = 1.30, 95% CI 1.04-1.63), and risks were increased when use started after the age of 21, was used for <5 years or stopped for >20 years before diagnosis. DLBCL, on the other hand, was not associated with hormonal contraception (pooled OR = 0.87, 95% CI 0.65-1.16).

CONCLUSIONS

Hormonal contraception is associated with an increased risk of FL but not of DLBCL or NHL overall.

ERα36, a new variant of the ERα is expressed in triple negative breast carcinomas and has a specific transcriptomic signature in breast cancer cell lines

Triple negative breast cancer is deprived of estrogen receptor alpha (ERα), progesterone receptor (PR) and HER-2 protein. It constitutes the most heterogeneous and aggressive group of breast carcinomas, for which identification of novel characteristics and characterization of putative targets becomes very demanding. In the present work we have assayed the expression of ERα36, a recently identified ERα variant of 36kDa, in a series of triple negative breast cancers, in relation to the clinical behavior and other clinico-pathological features of the tumors. While widely expressed within the cytoplasm in almost all tumors, we found that exclusively the membrane/submembrane expression of the receptor exhibits a correlation with patient's survival. Moreover, membrane ERα36 correlates in an inverse manner with the expression of miRNA210, a pro-angiogenic miR, with high prognostic relevance in triple negative carcinomas. A thorough transcriptomic, pharmacological-based approach in breast cancer cell lines, revealed an early (direct) transcriptional signature of the receptor activation, related to immune system processes and T-cell differentiation, RNA biosynthesis, regulation of metabolism, VEGF signaling and regulation of the cell cycle, with a down-regulation of CREB, NFκB and STATs transcription factors. Finally, ERα36 expression is not limited within breast cancer epithelial linen, but is equally identified in tumor vasculature, peritumoral fat tissue, lymphocytic infiltrate and stromal fibroblasts. In light of the above, ERα36 could represent a major counterpart in triple negative breast cancer.

Autoantibodies to estrogen receptor α interfere with T lymphocyte homeostasis and are associated with disease activity in systemic lupus erythematosus

OBJECTIVE

Estrogens influence many physiologic processes and are also implicated in the development or progression of numerous diseases, including autoimmune disorders. Aberrations of lymphocyte homeostasis that lead to the production of multiple pathogenic autoantibodies, including autoantibodies specific to estrogen receptor (ER), have been detected in the peripheral blood of patients with systemic lupus erythematosus (SLE). This study was undertaken to assess the presence of both anti-ERα and anti-ERβ antibodies in sera from patients with SLE, to analyze the effect of these antibodies on peripheral blood T lymphocyte homeostasis, and to evaluate their role as determinants of disease pathogenesis and progression.

METHODS

Anti-ER antibody serum immunoreactivity was analyzed by enzyme-linked immunosorbent assay in samples from 86 patients with SLE and 95 healthy donors. Phenotypic and functional analyses were performed by flow cytometry and Western blotting.

RESULTS

Anti-ERα antibodies were present in 45% of the patients with SLE, whereas anti-ERβ antibodies were undetectable. In healthy donors, anti-ERα antibodies induced cell activation and consequent apoptotic cell death in resting lymphocytes as well as proliferation of anti-CD3-stimulated T lymphocytes. A significant association between anti-ERα antibody values and clinical parameters, i.e., the SLE Disease Activity Index and arthritis, was found.

CONCLUSION

Our data suggest that anti-ERα autoantibodies interfere with T lymphocyte homeostasis and are significantly associated with lupus disease activity.

Reproductive immunology: a focus on the role of female sex hormones and other gender-related factors

Reproductive immunology has attracted the attention of researchers interested in fertility and pregnancy as well as those interested in immunity and autoimmunity. Over the past couple of decades, a wealth of data on the immune-reproductive interactions has been generated. This issue of the Journal will examine several topics including the role of immune factors in the induction of anti-Ro antibody-mediated autoimmunity in neonates and the immunological effects of gender and sex hormones. The possible implications of the research reviewed here for the development of novel therapeutic approaches are also addressed.

Estrogen receptors in immunity and autoimmunity

Due to the female predominance of autoimmune diseases, the role of gender and sex hormones in the immune system is of long-term interest. Estrogen's primary effects are mediated via estrogen receptors alpha and beta (ER α/β) that are expressed on most immune cells. ERs are nuclear hormone receptors that can either directly bind to estrogen response elements in gene promoters or serve as cofactors with other transcription factors (i.e., NFkB/AP1). Cytoplasmic ER and membrane associated ER impact specific kinase signaling pathways. ERs have prominent effects on immune function in both the innate and adaptive immune responses. Genetic deficiency of ERα in murine models of lupus resulted in significantly decreased disease and prolonged survival, while ERβ deficiency had minimal to no effect in autoimmune models. The protective effect of ERα in lupus is multifactoral. In arthritis models, ERα agonists appears to mediate a protective effect. The modulation of ERα function appears to be a potential target for therapy in autoimmunity.