Estrogen receptor alpha (ERalpha) deficiency in macrophages results in increased stimulation of CD4+ T cells while 17beta-estradiol acts through ERalpha to increase IL-4 and GATA-3 expression in CD4+ T cells independent of antigen presentation

17-β Estradiol (E2) distinctly regulates the expression of IL-4 and IL-13 in Th2 cells via modulating the interplay between GATA3 and PU.1

17-β Estradiol (E2) has long standing known functions in regulating human physiology as well as immune system. E2 is known to elicit a protective role against experimental autoimmune encephalomyelitis (EAE) and has been used as a drug for treatment against multiple sclerosis. Moreover, E2 regulates the adaptive immune system by directly affecting the T helper cell subsets differentiation and antibody secretion mediated by B cells. Reports have shown that E2 promotes Th1 and Treg cell differentiation; whereas it attenuated the Th17 and Tfh cell differentiation. Albeit multiple and contrasting studies, the mechanisms of behind E2 action on Th2 cells remained understudied. Hence, we sought to dissect the impact of E2 in Th2 cell differentiation. In this study, we elucidated the molecular mechanisms behind E2-mediated regulation of the differentiation of Th2 cells. We observed that E2 significantly attenuated the IL-4-secreting Th2 population in an ERα-dependent manner. We validated these findings using ICI 182, 780, an antagonist to ERα, not ERβ and ectopically overexpressing ERα in Th2 cells. We further determined that ERα alters the recruitment of GATA3 and PU.1 to Il4 gene by directly interacting with them. This altered recruitment was observed to be stronger at Il4 than Il13 locus. Interestingly, we detected a distinct recruitment of GATA3 and PU.1 at Il13 gene; however, there was no E2-mediated broad alteration in the recruitment of histone-modifiers at Il13 locus. These findings suggest that E2 regulates Il4 in a distinctly separate mechanism as opposed to Il13 locus in Th2 cells.

Sex differences in a murine model of asthma are time and tissue compartment dependent

CONCLUSION

Sexual dimorphism in lung inflammation is both time and tissue compartment dependent. Spatiotemporal variability in sex differences in a murine model of asthma must be accounted for when planning experiments to model the sex bias in allergic inflammation.

Sex and gender differences in myocarditis and dilated cardiomyopathy: An update

In the past decade there has been a growing interest in understanding sex and gender differences in myocarditis and dilated cardiomyopathy (DCM), and the purpose of this review is to provide an update on this topic including epidemiology, pathogenesis and clinical presentation, diagnosis and management. Recently, many clinical studies have been conducted examining sex differences in myocarditis. Studies consistently report that myocarditis occurs more often in men than women with a sex ratio ranging from 1:2-4 female to male. Studies reveal that DCM also has a sex ratio of around 1:3 women to men and this is also true for familial/genetic forms of DCM. Animal models have demonstrated that DCM develops after myocarditis in susceptible mouse strains and evidence exists for this progress clinically as well. A consistent finding is that myocarditis occurs primarily in men under 50 years of age, but in women after age 50 or post-menopause. In contrast, DCM typically occurs after age 50, although the age that post-myocarditis DCM occurs has not been investigated. In a small study, more men with myocarditis presented with symptoms of chest pain while women presented with dyspnea. Men with myocarditis have been found to have higher levels of heart failure biomarkers soluble ST2, creatine kinase, myoglobin and T helper 17-associated cytokines while women develop a better regulatory immune response. Studies of the pathogenesis of disease have found that Toll-like receptor (TLR)2 and TLR4 signaling pathways play a central role in increasing inflammation during myocarditis and in promoting remodeling and fibrosis that leads to DCM, and all of these pathways are elevated in males. Management of myocarditis follows heart failure guidelines and there are currently no disease-specific therapies. Research on standard heart failure medications reveal important sex differences. Overall, many advances in our understanding of the effect of biologic sex on myocarditis and DCM have occurred over the past decade, but many gaps in our understanding remain. A better understanding of sex and gender effects are needed to develop disease-targeted and individualized medicine approaches in the future.

Dual activation of estrogen receptor alpha and glucocorticoid receptor upregulate CRTh2-mediated type 2 inflammation; mechanism driving asthma severity in women?

BACKGROUND

Type 2-high asthma is characterized by elevated levels of circulating Th2 cells and eosinophils, cells that express chemoattractant-homologous receptor expressed on Th2 cells (CRTh2). Severe asthma is more common in women than men; however, the underlying mechanism(s) remain elusive. Here we examined whether the relationship between severe asthma and type 2 inflammation differs by sex and if estrogen influences Th2 cell response to glucocorticoid (GC).

METHODS

Type 2 inflammation and the proportion of blood Th2 cells (CD4⁺ CRTh2⁺ ) were assessed in whole blood from subjects with asthma (n = 66). The effects of GC and estrogen receptor alpha (ERα) agonist on in vitro differentiated Th2 cells were examined. Expression of CRTh2, type 2 cytokines and degree of apoptosis (Annexin V⁺ , 7-AAD) were determined by flow cytometry, qRT-PCR, western blot and ELISA.

RESULTS

In severe asthma, the proportion of circulating Th2 cells and hospitalizations were higher in women than men. Women with severe asthma also had more Th2 cells and serum IL-13 than women with mild/moderate asthma. Th2 cells, eosinophils and CRTh2 mRNA correlated with clinical characteristics associated with asthma control in women but not men. In vitro, GC and ERα agonist treated Th2 cells exhibited less apoptosis, more CRTh2 as well as IL-5 and IL-13 following CRTh2 activation than Th2 cells treated with GC alone.

CONCLUSION

Women with severe asthma had higher levels of circulating Th2 cells than men, which may be due to estrogen modifying the effects of GC, enhancing Th2 cell survival and type 2 cytokine production.

The hormonal environment and estrogen receptor signaling alters Chlamydia muridarum infection in vivo

Genital Chlamydia is the most common bacterial sexually transmitted infection in the United States and worldwide. Previous studies indicate that the progression of chlamydial infection is influenced by various factors, including the female sex hormones estrogen and progesterone. Sex hormone levels naturally fluctuate in women throughout their menstrual cycle. Varying concentrations of estrogen and progesterone may impact the progression of chlamydial infection and the host's immune response to Chlamydia. Estrogen signals through estrogen receptors (ERs), ERα and ERβ. These receptors are similar in structure and function, but are differentially expressed in tissues throughout the body, including the genital tract and on cells of the immune system. In this study, we used ovariectomized (OVT) BALB/c mice to investigate the impact of long-term administration of physiologically relevant concentrations of estrogen (E2), progesterone (P4), or a combination of E2/P4 on the progression of and immune response to C. muridarum infection. Additionally, we used ERα and ERβ knockout C57/BL6 mice to determine the how ERs affect chlamydial infection and the resulting immune response. Estrogen exposure prevented C. muridarum infection in vaginally infected OVT mice exposed to E2 alone or in combination with P4, while OVT or Sham mice exposed to hormone free, P4 or depo-medroxyprogesterone acetate shed similar amounts of chlamydiae. The hormonal environment also altered T cell recruitment and IFNϵ production the genital tracts of infected OVT and Sham mice on day 10 post infection. The absence of ERα, but not ERβ, in ER knockout mouse strains significantly changed the timing of C. muridarum infection. ERαKO mice shed significantly more chlamydiae at day 3 post infection and resolved the infection faster than WT or ERβKO animals. At day 9 post infection, flow cytometry showed that ERαKO mice had more T cells present and targeted RNA sequencing revealed increased expression of CD4 and FOXP3, suggesting that ERαKO mice had increased numbers of regulatory T cells compared to ERβKO and WT mice. Mock and chlamydia-infected ERαKO mice also expressed more IFNϵ early during infection. Overall, the data from these studies indicate that sex hormones and their receptors, particularly ERα and ERβ, differentially affect C. muridarum infection in murine models of infection.

Sex bias in lymphocytes: Implications for autoimmune diseases

Autoimmune diseases are characterized by a significant sex dimorphism, with women showing increased susceptibility to disease. This is, at least in part, due to sex-dependent differences in the immune system that are influenced by the complex interplay between sex hormones and sex chromosomes, with contribution from sociological factors, diet and gut microbiota. Sex differences are evident in the number and function of lymphocyte populations. Women mount a stronger pro-inflammatory response than males, with increased lymphocyte proliferation, activation and pro-inflammatory cytokine production, whereas men display expanded regulatory cell subsets. Ageing alters the immune landscape of men and women in differing ways, resulting in changes in autoimmune disease susceptibility. Here we review the current literature on sex differences in lymphocyte function, the factors that influence this, and the implications for autoimmune disease. We propose that improved understanding of sex bias in lymphocyte function can provide sex-specific tailoring of treatment strategies for better management of autoimmune diseases.

Sex—the most underappreciated variable in research: insights from helminth-infected hosts

The sex of a host affects the intensity, prevalence, and severity of helminth infection. In many cases, one sex has been found to be more susceptible than the other, with the prevalence and intensity of helminth infections being generally higher among male than female hosts; however, many exceptions exist. This observed sex bias in parasitism results primarily from ecological, behavioural, and physiological differences between males and females. Complex interactions between these influences modulate the risk of infection. Indeed, an interplay among sex hormones, sex chromosomes, the microbiome and the immune system significantly contributes to the generation of sex bias among helminth-infected hosts. However, sex hormones not only can modulate the course of infection but also can be exploited by the parasites, and helminths appear to have developed molecules and pathways for this purpose. Furthermore, host sex may influence the efficacy of anti-helminth vaccines; however, although little data exist regarding this sex-dependent efficacy, host sex is known to influence the response to vaccines. Despite its importance, host sex is frequently overlooked in parasitological studies. This review focuses on the key contributors to sex bias in the case of helminth infection. The precise nature of the mechanisms/factors determining these sex-specific differences generally remains largely unknown, and this represents an obstacle in the development of control methods. There is an urgent need to identify any protective elements that could be targeted in future therapies to provide optimal disease management with regard to host sex. Hence, more research is needed into the impact of host sex on immunity and protection.

The CRTh2 polymorphism rs533116 G > A associates with asthma severity in older females

Background

CRTh2 is G protein coupled receptor for prostaglandin D2 (PGD)₂ expressed by immune cells that drive type 2 inflammation such as CD4⁺ T cells (Th2), eosinophils and group 2 innate lymphoid cells (ILC2) as well as structural cells including smooth muscle and epithelium. CRTh2-expressing cells are increased in the blood and airways of asthmatics and severe asthma is characterized by increased activity of the PGD₂-CRTh2 pathway. The CRTh2 single nucleotide polymorphism (SNP) rs533116 G > A is associated with development of asthma and increased Th2 cell differentiation.

Objective

To examine whether CRTh2 rs533116G > A associates with asthma severity. Since severe asthma is more common in females than males, we performed a sex-stratified analysis.

Methods

Clinical data from asthmatics (n = 170) were obtained from clinic visits and chart review. Asthma severity was assessed according to ERS/ATS guidelines. Peripheral blood cells were characterized by flow cytometry and qRT-PCR. Genotyping was performed by TaqMan assay.

Results

Older females (≥45 years) homozygous for minor A allele of rs533116 were more likely to have severe asthma, lower FEV₁, a higher prescribed dose of inhaled corticosteroid and more type 2 inflammation than females carrying GA or GG genotypes. Comparing females and males with the AA genotype also revealed that women had more type 2 inflammation.

Conclusions and significance

The polymorphism CRTh2 rs533116 G > A associates with severe asthma and type 2 inflammation in older females. This study reveals a gene-sex-aging interaction influencing the effect of CRTh2 on asthma severity.

Effects of sex steroids on thymic epithelium and thymocyte development

Sex steroid hormones have major effects on the thymus. Age-related increases in androgens and estrogens and pregnancy-induced increases in progestins all cause dramatic thymic atrophy. Atrophy can also be induced by treatment with exogenous sex steroids and reversed by ablation of endogenous sex steroids. Although these observations are frequently touted as evidence of steroid lymphotoxicity, they are often driven by steroid signaling in thymic epithelial cells (TEC), which are highly steroid responsive. Here, we outline the effects of sex steroids on the thymus and T cell development. We focus on studies that have examined steroid signaling in vivo, aiming to emphasize the actions of endogenous steroids which, via TEC, have remarkable programming effects on the TCR repertoire. Due to the dramatic effects of steroids on TEC, especially thymic involution, the direct effects of sex steroid signaling in thymocytes are less well understood. We outline studies that could be important in addressing these possibilities, and highlight suggestive findings of sex steroid generation within the thymus itself.

Hormonal Effects on Asthma, Rhinitis, and Eczema

Hormones significantly influence the pathogenesis of asthma, rhinitis, and eczema. This review aims to summarize relevant clinical considerations for practicing allergists and immunologists. The first section reviews the effects of sex hormones: estrogen, progesterone, and testosterone. The second concerns insulin production in the context of type 1 and type 2 diabetes. The third concludes with a discussion of thyroid and adrenal pathology in relationship to asthma, rhinitis, and eczema.

The anti-inflammatory effect of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice

AIMS

Allergic rhinitis (AR), a major chronic inflammatory disease of the respiratory system, is a public health issue because of its substantial negative impact on quality of life and work efficiency alongside its high prevalence and costs. Dapsone is a sulfone chemical with reported anti-inflammatory and antibacterial properties. Accordingly, we investigated the anti-inflammatory impact of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice.

MAIN METHODS

Intraperitoneal ovalbumin and hydroxide aluminum injection followed by intranasal ovalbumin administration sensitized female Balb/c mice. Mice received intraperitoneal dapsone either acute (5, 10, 20 mg/kg) 30 min before the last ovalbumin challenge, or chronic (20 mg/kg) on days 21 to 35.

KEY FINDINGS

Both acute and chronic intraperitoneal usage of dapsone showed a considerable decrease in the nasal scratching behavior, the number of sneezing, serum IL-4 and IgE levels of ovalbumin-induced AR in balb/c mice, but there was a significant increase in serum IFNγ level. Histopathological analysis demonstrated a significant reduction of eosinophil numbers, following dapsone injection. Goblet cell hyperplasia and respiratory epithelial-thickness decreased significantly in the acute and chronic 20 mg/kg dapsone groups compared to the ovalbumin-induced controls.

SIGNIFICANCE

This study shows that there is an association between acute and chronic dapsone treatment and some anti-allergic effects through an inflammation cascade.

The Impact of Estrogens and Their Receptors on Immunity and Inflammation during Infection

Simple Summary

Human health is significantly affected by microbial infections. One of the largest determinants of the outcomes of such infections is the host immune response. Too weak of a response can lead to enhanced spread by the pathogen, while an overstimulated response can lead to immune-induced tissue damage. Thus, to effectively treat infected individuals, it is critical to understand the regulators that control inflammatory responses. Recently, it has become widely accepted that estrogens, a class of sex hormones, are capable of dramatically altering the responses of host cells to microbes. In this review, we discuss how estrogens change the host immune response, as well as how these changes can alter the outcome of the infection for the individual.

Abstract

Sex hormones, such as estrogen and testosterone, are steroid compounds with well-characterized effects on the coordination and development of vertebrate reproductive systems. Since their discovery, however, it has become clear that these “sex hormones” also regulate/influence a broad range of biological functions. In this review, we will summarize some current findings on how estrogens interact with and regulate inflammation and immunity. Specifically, we will focus on describing the mechanisms by which estrogens alter immune pathway activation, the impact of these changes during infection and the development of long-term immunity, and how different types of estrogens and their respective concentrations mediate these outcomes.

Novel systemic treatments in atopic dermatitis: Are there sex differences?

Atopic dermatitis (AD) is a common inflammatory skin disease with a significant global disease burden. Several mechanisms underlie AD, such as epidermal barrier dysfunction and immune dysregulation, which have led to innovative systemic treatment options. Other inflammatory disorders, as well as innate and adaptive immune responses, have noted sex differences, but our article highlights a paucity of data on the impact of sex, gender, and gender identity on the pathophysiology and systemic treatments of AD.

Can Digit Ratio (2D:4D) Be Indicative of Predispositions to Autoimmune Thyroid Diseases in Women - Hashimoto Thyroiditis and Graves' Disease?

Hashimoto thyroiditis and Graves' disease are autoimmune thyroid diseases which occur much more frequently in women than in men. Estrogen receptors are found in the thyroid gland and can modulate the gland's function. Digit ratio (2D:4D) is thought to be a negative correlate of prenatal testosterone and a positive correlate of prenatal estrogen. This study aimed to examine a relationship between right and left 2D:4D in women with Hashimoto thyroiditis and Graves' disease. The cross-sectional study included 106 women with autoimmune thyroid disease: 73 women diagnosed with Hashimoto thyroiditis and 33 women with Graves' disease, together with 70 healthy women as controls. Second and fourth digit length, weight, height were measured directly, and 2D:4D and BMI were calculated. Compared to controls, right and left 2D:4D were significantly higher in women with Hashimoto thyroiditis and lower in women with Graves' disease, the effects were higher for right 2D:4D. The mean length of right 4D was significantly lower in the examined women with Hashimoto thyroiditis than in Graves' disease. Higher right and left 2D:4D in women with Hashimoto thyroiditis suggests that prenatal exposure to high levels of estrogens relative to testosterone may play a role in the development of this disease. Lower right and left 2D:4D in women with Graves' disease suggest a role of high prenatal androgens relative to estrogens in Graves' disease pathogenesis.

Nonrespiratory Comorbidities in Asthma

Asthma is a chronic heterogeneous airway disease. Common comorbid conditions are often disproportionately present in severe asthma. Optimal care of patients with asthma requires the recognition and treatment of these comorbid conditions. This review outlines the pathophysiological mechanisms between nonrespiratory comorbid conditions and asthma and their effect on asthma outcomes. They include: type 2 diabetes mellitus, hypertension, atherosclerotic cardiovascular disease, adrenal and thyroid gland diseases, pregnancy, osteoporosis, adverse effects from medications, and mental health disorders. Studies indicate how poor glycemic control of type 2 diabetes mellitus is associated with not only greater health care utilization but poorer asthma outcomes. Also, a large health care claims database indicates that a substantial proportion of pregnant women have uncontrolled asthma and are prescribed suboptimal controller therapy. Additional data about these nonrespiratory comorbidities and medications known to benefit both nonrespiratory comorbidities and asthma are necessary.

Multispecies Q Fever Outbreak in a Mixed Dairy Goat and Cattle Farm Based on a New Bovine-Associated Genotype of Coxiella burnetii

A Q fever outbreak on a dairy goat and cattle farm was investigated with regard to the One Health concept. Serum samples and vaginal swabs from goats with different reproductive statuses were collected. Cows, cats, and a dog were investigated with the same sample matrix. The farmer's family was examined by serum samples. Ruminant sera were analyzed with two phase-specific enzyme-linked immunoassays (ELISAs). Dominant immunoglobulin G (IgG) phase II levels reflected current infections in goats. The cows had high IgG phase I and II levels indicating ongoing infections. Feline, canine, and human sera tested positive by indirect fluorescent antibody test (IFAT). Animal vaginal swabs were analyzed by qPCR to detect C. burnetii, and almost all tested positive. A new cattle-associated C. burnetii genotype C16 was identified by the Multiple-Locus Variable-number tandem repeat Analysis (MLVA/VNTR) from ruminant samples. Additionally, a possible influence of 17ß-estradiol on C. burnetii antibody response was evaluated in goat sera. Goats in early/mid-pregnancy had significantly lower levels of phase-specific IgGs and 17ß-estradiol than goats in late pregnancy. We conclude that the cattle herd may have transmitted C. burnetii to the pregnant goat herd, resulting in a Q fever outbreak with one acute human case. The influence of placentation and maternal pregnancy hormones during pregnancy on the immune response is discussed.

Sensory Neurons, Neuroimmunity, and Pain Modulation by Sex Hormones

The inclusion of women in preclinical pain studies has become more commonplace in the last decade as the National Institutes of Health (NIH) released its "Sex as a Biological Variable" mandate. Presumably, basic researchers have not had a comprehensive understanding about neuroimmune interactions in half of the population and how hormones play a role in this. To date, we have learned that sex hormones contribute to sexual differentiation of the nervous system and sex differences in behavior throughout the lifespan; however, the cycling of sex hormones does not always explain these differences. Here, we highlight recent advances in our understanding of sex differences and how hormones and immune interactions influence sensory neuron activity to contribute to physiology and pain. Neuroimmune mechanisms may be mediated by different cell types in each sex, as the actions of immune cells are sexually dimorphic. Unfortunately, the majority of studies assessing neuronal contributions to immune function have been limited to males, so it is unclear if the mechanisms are similar in females. Finally, pathways that control cellular metabolism, like nuclear receptors, have been shown to play a regulatory role both in pain and inflammation. Overall, communication between the neuroimmune and endocrine systems modulate pain signaling in a sex-dependent manner, but more research is needed to reveal nuances of these mechanisms.

Sex, Cells, and Asthma

There are marked sex differences in asthma prevalence and severity. Sex hormones play a central role in these sex biases and directly interact with multiple key cells involved in the pathogenesis of asthma. Here we review the known effects of estrogen, progesterone, and testosterone on airway epithelial cells, airway smooth muscle cells, the mononuclear phagocyte system, innate lymphoid cells, eosinophils, mast cells, T cells, and B cells, all in the context of asthma. Furthermore, we explore unresolved clinical questions, such as the role of sex hormones in the link between asthma and obesity.

Estrogenic bias in T-Lymphocyte biology: Implications for cardiovascular disease

Gender bias in cardiovascular disease has been extensively documented in epidemiological and clinical studies. Despite this, the precise molecular mechanisms underlying these disparities between men and women are poorly understood. It is clear that physiological concentrations of estradiol, such as those present in pre-menopausal women, exert cardioprotective effects that are absent in men or in post-menopausal women. These cardioprotective effects, in part, are due to the estrogen receptor-mediated modulation of the immune system including T-cells. Estrogen receptors (ERs) are widely expressed in different T-cell subsets which are known to play an indispensable role in the progression of cardiovascular disease. Because T-cells can be polarized into several distinct subsets depending on the activation milieu, they can have many different, potentially opposing functions, and it is unclear what roles estrogen receptor signaling may play in mediating these functions. This is further complicated by the discrete and often antagonistic actions of different ERs on T-cell biology which dictate the balance between numerous ER-dependent signaling pathways. While myriad effects of estrogen in T-cells are relevant for many cardiovascular diseases, their widespread effects on several other (patho)physiological systems introduce several obstacles to understanding ER signaling and its precise effects on the immune system. This review aims to provide a more comprehensive summary of the mechanisms of estrogen receptor-mediated modulation of T-cell function, polarization, and cytokine production in the context of cardiovascular disease.

Sex Hormones and Lung Inflammation

Inflammation is a characteristic marker in numerous lung disorders. Several immune cells, such as macrophages, dendritic cells, eosinophils, as well as T and B lymphocytes, synthetize and release cytokines involved in the inflammatory process. Gender differences in the incidence and severity of inflammatory lung ailments including asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (PF), lung cancer (LC), and infectious related illnesses have been reported. Moreover, the effects of sex hormones on both androgens and estrogens, such as testosterone (TES) and 17β-estradiol (E2), driving characteristic inflammatory patterns in those lung inflammatory diseases have been investigated. In general, androgens seem to display anti-inflammatory actions, whereas estrogens produce pro-inflammatory effects. For instance, androgens regulate negatively inflammation in asthma by targeting type 2 innate lymphoid cells (ILC2s) and T-helper (Th)-2 cells to attenuate interleukin (IL)-17A-mediated responses and leukotriene (LT) biosynthesis pathway. Estrogens may promote neutrophilic inflammation in subjects with asthma and COPD. Moreover, the activation of estrogen receptors might induce tumorigenesis. In this chapter, we summarize the most recent advances in the functional roles and associated signaling pathways of inflammatory cellular responses in asthma, COPD, PF, LC, and newly occurring COVID-19 disease. We also meticulously deliberate the influence of sex steroids on the development and progress of these common and severe lung diseases.

An overview of Betacoronaviruses-associated severe respiratory syndromes, focusing on sex-type-specific immune responses

Emerging beta-coronaviruses (β-CoVs), including Severe Acute Respiratory Syndrome CoV-1 (SARS-CoV-1), Middle East Respiratory Syndrome-CoV (MERS-CoV), and Severe Acute Respiratory Syndrome CoV-2 (SARS-CoV-2, the cause of COVID19) are responsible for acute respiratory illnesses in human. The epidemiological features of the SARS, MERS, and new COVID-19 have revealed sex-dependent variations in the infection, frequency, treatment, and fatality rates of these syndromes. Females are likely less susceptible to viral infections, perhaps due to their steroid hormone levels, the impact of X-linked genes, and the sex-based immune responses. Although mostly inactive, the X chromosome makes the female's immune system more robust. The extra immune-regulatory genes of the X chromosome are associated with lower levels of viral load and decreased infection rate. Moreover, a higher titer of the antibodies and their longer blood circulation half-life are involved in a more durable immune protection in females. The activation rate of the immune cells and the production of TLR7 and IFN are more prominent in females. Although the bi-allelic expression of the immune regulatory genes can sometimes lead to autoimmune reactions, the higher titer of TLR7 in females is further associated with a stronger anti-viral immune response. Considering these sex-related differences and the similarities between the SARS, MERS, and COVID-19, we will discuss them in immune responses against the β-CoVs-associated syndromes. We aim to provide information on sex-based disease susceptibility and response. A better understanding of the evasion strategies of pathogens and the host immune responses can provide worthful insights into immunotherapy, and vaccine development approaches.

The Challenge by Multiple Environmental and Biological Factors Induce Inflammation in Aging: Their Role in the Promotion of Chronic Disease

The aging process is driven by multiple mechanisms that lead to changes in energy production, oxidative stress, homeostatic dysregulation and eventually to loss of functionality and increased disease susceptibility. Most aged individuals develop chronic low-grade inflammation, which is an important risk factor for morbidity, physical and cognitive impairment, frailty, and death. At any age, chronic inflammatory diseases are major causes of morbimortality, affecting up to 5-8% of the population of industrialized countries. Several environmental factors can play an important role for modifying the inflammatory state. Genetics accounts for only a small fraction of chronic-inflammatory diseases, whereas environmental factors appear to participate, either with a causative or a promotional role in 50% to 75% of patients. Several of those changes depend on epigenetic changes that will further modify the individual response to additional stimuli. The interaction between inflammation and the environment offers important insights on aging and health. These conditions, often depending on the individual's sex, appear to lead to decreased longevity and physical and cognitive decline. In addition to biological factors, the environment is also involved in the generation of psychological and social context leading to stress. Poor psychological environments and other sources of stress also result in increased inflammation. However, the mechanisms underlying the role of environmental and psychosocial factors and nutrition on the regulation of inflammation, and how the response elicited for those factors interact among them, are poorly understood. Whereas certain deleterious environmental factors result in the generation of oxidative stress driven by an increased production of reactive oxygen and nitrogen species, endoplasmic reticulum stress, and inflammation, other factors, including nutrition (polyunsaturated fatty acids) and behavioral factors (exercise) confer protection against inflammation, oxidative and endoplasmic reticulum stress, and thus ameliorate their deleterious effect. Here, we discuss processes and mechanisms of inflammation associated with environmental factors and behavior, their links to sex and gender, and their overall impact on aging.

Long-term exposure to low 17α-ethinylestradiol (EE2) concentrations disrupts both the reproductive and the immune system of juvenile rainbow trout, Oncorhynchus mykiss

Estrogenic endocrine disrupting compounds (EEDCs), such as ethinylestradiol (EE2), are well studied for their impact on the reproductive system of fish. EEDCs may also impact the immune system and, as a consequence, the disease susceptibility of fish. It is currently not yet known whether the low concentrations of EEDCs that are able to disrupt the reproductive system of trout are effective in disrupting the immune system and the fish host resistance towards pathogens, too, or whether such immunodisruptive effects would occur only at higher EEDC concentrations. Therefore, in the present study we compare the effect thresholds of low 17α-ethinylestradiol concentrations (1.5 and 5.5 EE2 ng/L) on the reproductive system, the immune system, the energy expenditures and the resistance of juvenile rainbow trout (Oncorhynchus mykiss) against the parasite Tetracapsuloides bryosalmonae - the etiological agent of proliferative kidney disease (PKD) of salmonids. The parasite infection was conducted without injection and under low pathogen exposure concentrations. The disease development was followed over 130 days post infection - in the presence or absence of EE2 exposure. The results show that the long-term EE2 exposure affected, at both concentrations, reproductive parameters like the mRNA levels of hepatic vitellogenin and estrogen receptors. At the same concentrations, EE2 exposure modulated the immune parameters: mRNA levels of several immune genes were altered and the parasite intensity as well as the disease severity (histopathology) were significantly reduced in EE2-exposed fish compared to infected control fish. The combination of EE2 exposure and parasite infection was energetically costly, as indicated by the decreased values of the swim tunnel respirometry. Although further substantiation is needed, our findings suggest that EE2 exerts endocrine disruptive and immunomodulating activities at comparable effect thresholds, since reproductive and immune parameters were affected by the same, low EE2 concentrations.

Equally Interchangeable? How Sex and Gender Affect Transplantation

Organ transplantation as an option to overcome end-stage diseases is common in countries with advanced healthcare systems and is increasingly provided in emerging and developing countries. A review of the literature points to sex- and gender-based inequity in the field with differences reported at each step of the transplant process, including access to a transplantation waiting list, access to transplantation once waitlisted, as well as outcome after transplantation. In this review, we summarize the data regarding sex- and gender-based disparity in adult and pediatric kidney, liver, lung, heart, and hematopoietic stem cell transplantation and argue that there are not only biological but also psychological and socioeconomic issues that contribute to disparity in the outcome, as well as an inequitable access to transplantation for women and girls. Because the demand for organs has always exceeded the supply, the transplant community has long recognized the need to ensure equity and efficiency of the organ allocation system. In the spirit of equity and equality, the authors call for recognition of these inequities and the development of policies that have the potential to ensure that girls and women have equitable access to transplantation.

Elevated circulating Th2 but not group 2 innate lymphoid cell responses characterize canine atopic dermatitis

Atopic dermatitis (AD) is an allergic skin disease that causes significant morbidity and affects multiple species. AD is highly prevalent in companion dogs, and the clinical management of the disease remains challenging. An improved understanding of the immunologic and genetic pathways that lead to disease could inform the development of novel treatments. In allergic humans and mouse models of AD, the disease is associated with Th2 and group 2 innate lymphoid cell (ILC2) activation that drives type 2 inflammation. Type 2 inflammation also appears to be associated with AD in dogs, but gaps remain in our understanding of how key type 2-associated cell types such as canine Th2 cells and ILC2s contribute to the pathogenesis of canine AD. Here, we describe previously uncharacterized canine ILC2-like cells and Th2 cells ex vivo that produced type 2 cytokines and expressed the transcription factor Gata3. Increased circulating Th2 cells were associated with chronic canine AD. Single-cell RNA sequencing revealed a unique gene expression signature in T cells in dogs with AD. These findings underline the importance of pro-allergic Th2 cells in orchestrating AD and provide new methods and pathways that can inform the development of improved therapies.

Oestrogen amplifies pre-existing atopy-associated Th2 bias in an experimental asthma model

BACKGROUND

The prevalence and severity of asthma, particularly the most common (atopic) form of the disease, increase amongst females but not males after puberty, and asthma activity also changes throughout the menstrual cycle and during pregnancy. The contribution of female sex hormones to asthma pathogenesis is incompletely understood.

OBJECTIVE

To obtain insight into the role of oestrogen (E2) in experimental atopic asthma, and guide future research on sex-related variations in atopic asthma susceptibility/intensity in humans.

METHODS

We utilized an experimental model comprising rat strains expressing dichotomous Th2-high vs Th2-low immunophenotypes exemplified by eosinophilia, mirroring differences between human atopics/non-atopics. We compared the efficiency of Th2-associated immunoinflammatory mechanisms, which differed markedly between the two strains, and between sexes in the Th2-high strain, and determined the effects of E2 administration on these differences.

RESULTS

Unique to the Th2-high strain, eosinophil: neutrophil ratios in the airways at baseline and following sensitization/aeroallergen challenge were logfold higher in females relative to males, and this was reflected by higher baseline blood eosinophil numbers in females. Pretreatment of Th2-high males with E2 abrogated this sex difference by selectively boosting Th2-associated genes in the airways and eosinophilia, but was without corresponding effect in the Th2-low strain. In contrast, parallel E2 effects on myeloid and lymphoid cell populations were relatively modest.

CONCLUSIONS AND CLINICAL RELEVANCE

E2 acts to amplify the eosinophilic component of pre-existing Th2-high immunophenotype, possibly acting at the level of the common eosinophil/neutrophil precursor in bone marrow to preferentially drive eosinophil differentiation. Constitutive granulocyte profiles in which the balance between eosinophils and neutrophils is skewed towards eosinophils have been identified in independent cohort studies as markers of asthma risk, and these findings suggest that more detailed studies on the role of E2 in this context, and in relation to asthma pathogenesis in post-pubertal females in particular, appear warranted.

Abnormal Expression of ERα in Cholangiocytes of Patients With Primary Biliary Cholangitis Mediated Intrahepatic Bile Duct Inflammation

ERα, one of the classical receptors of estrogen, has been found to be abnormally up-regulated in patients with primary biliary cholangitis (PBC), which is an important factor leading to ductopenia. ERα-mediated signaling pathways are involved in proliferation of human intrahepatic biliary epithelial cells (HiBECs) and portal inflammation. Our previous studies have shown that the expression levels of ERα in the liver tissues of PBC patients are positively correlated with the levels of serum pro-inflammatory cytokines. The present study was designed to assess the relationship between abnormal ERα expression in small bile ducts and the progression of PBC. We examined the levels of multiple cytokines and analyzed their relationship with clinical parameters of livers functions in a cohort of 43 PBC patients and 45 healthy controls (HC). The levels of ERα expression and the relation with the levels of cytokines were further assessed. The localization of cytokines and ERα-mediated signaling pathways in liver were examined using immunohistochemistry. The possible underlying mechanisms of these alterations in PBC were explored in vitro. Our results demonstrated that the levels of IL-6, IL-8, and TNF-α were increased in PBC patients, and positively correlated with the serum AKP levels and ERα expression levels. Moreover, the expression of these cytokines were up-regulated in HiBECs that were stimulated with 17β-estradiol and PPT (an ERα agonist) and they also were positive in intrahepatic bile duct of PBC patients. The ERα-mediated expression of pro-inflammatory cytokines was induced by JNK, P38, and STAT3 phosphorylation in HiBECs. In addition, the CD54 expression was increased in HiBECs after ERα activation, which induced peripheral blood monouclear cells (PBMCs) recruitment. In conclusion, the present study highlighted a key role of abnormal ERα expression in inducing an inflammatory phenotype of HiBECs, which was critical in the development of inflammation and damage in small bile duct.

Antiestrogens in combination with immune checkpoint inhibitors in breast cancer immunotherapy

Breast cancers (BCs) with expression of estrogen receptor-alpha (ERα) occur in more than 70% of newly-diagnosed patients in the U.S. Endocrine therapy with antiestrogens or aromatase inhibitors is an important intervention for BCs that express ERα, and it remains one of the most effective targeted treatment strategies. However, a substantial proportion of patients with localized disease, and essentially all patients with metastatic BC, become resistant to current endocrine therapies. ERα is present in most resistant BCs, and in many of these its activity continues to regulate BC growth. Fulvestrant represents one class of ERα antagonists termed selective ER downregulators (SERDs). Treatment with fulvestrant causes ERα down-regulation, an event that helps overcome several resistance mechanisms. Unfortunately, full antitumor efficacy of fulvestrant is limited by its poor bioavailability in clinic. We have designed and tested a new generation of steroid-like SERDs. Using ERα-positive BC cells in vitro, we find that these compounds suppress ERα protein levels with efficacy similar to fulvestrant. Moreover, these new SERDs markedly inhibit ERα-positive BC cell transcription and proliferation in vitro even in the presence of estradiol-17β. In vivo, the SERD termed JD128 significantly inhibited tumor growth in MCF-7 xenograft models in a dose-dependent manner (P < 0.001). Further, our findings indicate that these SERDs also interact with ER-positive immune cells in the tumor microenvironment such as myeloid-derived suppressor cells (MDSC), tumor infiltrating lymphocytes and other selected immune cell subpopulations. SERD-induced inhibition of MDSCs and concurrent actions on CD8+ and CD4 + T-cells promotes interaction of immune checkpoint inhibitors with BC cells in preclinical models, thereby leading to enhanced tumor killing even among highly aggressive BCs such as triple-negative BC that lack ERα expression. Since monotherapy with immune checkpoint inhibitors has not been effective for most BCs, combination therapies with SERDs that enhance immune recognition may increase immunotherapy responses in BC and improve patient survival. Hence, ERα antagonists that also promote ER downregulation may potentially benefit patients who are unresponsive to current endocrine therapies.

The Roles of Sex Hormones in the Course of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by T helper 2 cell (Th2)-shifted abnormal immunity, skin barrier impairment, and pruritus. The prevalence of AD in childhood is slightly higher in boys than in girls; after puberty, the sexual difference is reversed. The female preponderance in all generations exists in intrinsic AD with enhanced Th1 activity and nickel allergy, lacking increased serum IgE or filaggrin mutation. AD is often deteriorated before menstruation. We review the effects of sex hormones on immune responses and skin permeability barrier and propose possible hypotheses for the above phenomena. After puberty, the immune responses of patients are remarkably influenced by sex hormones. Estrogen and progesterone enhance the activities of Th2/regulatory T cell (Treg) but suppress Th1/Th17. Androgens suppress Th1/Th2/Th17 and induce Treg. The skin permeability barrier is fortified by estrogen but is impaired by progesterone and androgens. Dehydroepiandrosterone suppresses Th2 but enhances Th1. The amount of steroid sulfatase converting dehydroepiandrosterone sulfate to dehydroepiandrosterone is higher in women than in men, and thus, women might be more susceptible to the influence of dehydroepiandrosterone. The balance of modulatory effects of sex hormones on immune responses and skin barrier might regulate the course of AD.

Estrogen receptor α in T cells suppresses follicular helper T cell responses and prevents autoimmunity

Estrogen receptor alpha (ERα) is a sex hormone nuclear receptor that regulates various physiological events, including the immune response. Although there have been some recent studies on ERα regarding subsets of T cells, such as Th1, Th2, Th17, and Treg cells, its role in follicular helper T (TFH) cells has not yet been elucidated. To determine whether ERα controls TFH response and antibody production, we generated T cell-specific ERα knockout (KO) mice by utilizing the CD4-Cre/ERα flox system (CD4-ERα KO) and then analyzed their phenotype. At approximately 1 year of age, CD4-ERα KO mice spontaneously showed mild autoimmunity with increased autoantibody production and CD4⁺CD44⁺CXCR5⁺Bcl-6⁺ TFH cells in the mesenteric lymph nodes and spleen. We next immunized 6-8-week-old CD4-ERα KO mice with sheep red blood cells (SRBCs), which resulted in an increased proportion of TFH cells and germinal center (GC) responses. In addition, 17β-estradiol (E2) treatment decreased TFH responses in wild-type mice and suppressed the mRNA expression of Bcl-6 and IL-21. Finally, we confirmed that the production of high-affinity antigen-specific antibodies and isotype class switching induced by NP-conjugated ovalbumin immunization were elevated in CD4-ERα KO mice under sufficient estrogen conditions. These results collectively demonstrate that the female sex hormone receptor ERα inhibits the TFH cell response and GC reaction to control autoantibody production, which was related to estrogen signaling and autoimmunity.

Immune Tumor Microenvironment in Breast Cancer and the Participation of Estrogen and Its Receptors in Cancer Physiopathology

Breast cancer is characterized by cellular and molecular heterogeneity. Several molecular events are involved in controlling malignant cell process. In this sense, the importance of studying multiple cell alterations in this pathology is overriding. A well-identified fact on immune response is that it can vary depend on sex. Steroid hormones and their receptors may regulate different functions and the responses of several subpopulations of the immune system. Few reports are focused on the function of estrogen receptors (ERs) on immune cells and their roles in different breast cancer subtypes. Thus, the aim of this review is to investigate the immune infiltrating tumor microenvironment and prognosis conferred by it in different breast cancer subtypes, discuss the current knowledge and point out the roles of estrogens and its receptors on the infiltrating immune cells, as well as to identify how different immune subsets are modulated after anti-hormonal treatments in breast cancer patients.

Estradiol Attenuates the Severity of Primary Toxoplasma gondii Infection-Induced Adverse Pregnancy Outcomes Through the Regulation of Tregs in a Dose-Dependent Manner

Estradiol (E2) plays a crucial and intricate role during pregnancy to mediate several aspects of the pregnancy process. A perplexing phenomenon in congenital toxoplasmosis is that the severity of Toxoplasma gondii (T. gondii)-mediated adverse pregnancy outcome is closely related with time of primary maternal infection during pregnancy. In this study, the results showed that T. gondii infection in early pregnancy was more likely to induce miscarriage in mice than in late pregnancy, which may be related to inflammation of the maternal–fetal interface. Meanwhile, the T. gondii infection-induced-apoptotic rate of Tregs was higher and the expression of programmed death-1 (PD-1) on Tregs was lower in early pregnancy than in late pregnancy. As the level of E2 in mouse serum gradually increased with the development of pregnancy, we proposed that E2 may contribute to the discrepancy of Tregs at different stages of pregnancy. Thus, we investigated in vitro and in vivo effects of E2 in regulating Tregs. We found that E2 in vitro could protect Tregs against apoptosis and upregulate the expression of PD-1 on Tregs in a dose-dependent manner through ERα. Likewise, the simulated mid-pregnancy level of E2 in nonpregnant mice also alleviated the T. gondii infection-induced apoptosis of Tregs and potentiated the PD-1 expression on Tregs. Therefore, in the pathogenesis of T. gondii-induced abnormal pregnancy, E2 helped maintain the immune balance and improve the pregnancy outcome through regulating Tregs. This finding illustrates the intricate working of hormone–immune system interaction in infection-induced abnormal pregnancy.

Immune-Specific Expression and Estrogenic Regulation of the Four Estrogen Receptor Isoforms in Female Rainbow Trout (Oncorhynchus mykiss)

Genomic actions of estrogens in vertebrates are exerted via two intracellular estrogen receptor (ER) subtypes, ERα and ERβ, which show cell- and tissue-specific expression profiles. Mammalian immune cells express ERs and are responsive to estrogens. More recently, evidence became available that ERs are also present in the immune organs and cells of teleost fish, suggesting that the immunomodulatory function of estrogens has been conserved throughout vertebrate evolution. For a better understanding of the sensitivity and the responsiveness of the fish immune system to estrogens, more insight is needed on the abundance of ERs in the fish immune system, the cellular ratios of the ER subtypes, and their autoregulation by estrogens. Consequently, the aims of the present study were (i) to determine the absolute mRNA copy numbers of the four ER isoforms in the immune organs and cells of rainbow trout, Oncorhynchus mykiss, and to compare them to the hepatic ER numbers; (ii) to analyse the ER mRNA isoform ratios in the immune system; and, (iii) finally, to examine the alterations of immune ER mRNA expression levels in sexually immature trout exposed to 17β-estradiol (E2), as well as the alterations of immune ER mRNA expression levels in sexually mature trout during the reproductive cycle. All four ER isoforms were present in immune organs—head kidney, spleen-and immune cells from head kidney and blood of rainbow trout, but their mRNA levels were substantially lower than in the liver. The ER isoform ratios were tissue- and cell-specific, both within the immune system, but also between the immune system and the liver. Short-term administration of E2 to juvenile female trout altered the ER mRNA levels in the liver, but the ERs of the immune organs and cells were not responsive. Changes of ER gene transcript numbers in immune organs and cells occurred during the reproductive cycle of mature female trout, but the changes in the immune ER profiles differed from those in the liver and gonads. The correlation between ER gene transcript numbers and serum E2 concentrations was only moderate to low. In conclusion, the low mRNA numbers of nuclear ER in the trout immune system, together with their limited estrogen-responsiveness, suggest that the known estrogen actions on trout immunity may be not primarily mediated through genomic actions, but may involve other mechanisms, such as non-genomic pathways or indirect effects.

Estrogen Stimulation Differentially Impacts Human Male and Female Antigen-Specific T Cell Anti-Tumor Function and Polyfunctionality

Sex-specific differences exist in innate and adaptive immune responses and are mediated by hormone signaling. Estrogen is able to differentially modulate the development and differentiation of immune cells, including T cells. However, the effect of estrogen on T cell function, especially at concentrations other than physiological, remains controversial and incompletely understood. Immunotherapy is one of the most promising cancer treatments to date with a high probability of future enhancements. The adoptive transfer of genetically modified T cells can mediate tumor regression but there are still many hurdles to enhancing the proficiency of this treatment. This study demonstrates for the first time that one major aspect to consider for designing potent immunotherapies for cancer is the impact of the patient's sex. Herein, using two different Ag-specific T cell groups, we investigated the effect of sex and estrogen in antitumor effector responses, T helper cytokine secretion, and, importantly, on T cell whole polyfunctionality important for memory T cell development and survival. Major differences were observed in T cell function and polyfunctionality between sexes and on E2 treatment. The findings of this study may be critical to understand the results of immunotherapy on different patients and for the enhancement of immunotherapy for cancer.

Prospective cohort study on the efficacy and safety of telbivudine used throughout pregnancy in blocking mother-to-child transmission of hepatitis B virus

Women with chronic hepatitis B should maintain nucleotide analogue treatment to prevent disease progression during pregnancy. The aim of this study was to prospectively evaluate the efficacy and safety of telbivudine used throughout pregnancy for preventing hepatitis B virus (HBV) mother-to-child transmission (MTCT). From January 2012 to June 2014, women who were receiving telbivudine therapy and became pregnant were enrolled in group A at 28 weeks of gestation. Pregnant women with an HBV DNA level >10⁶  IU/mL were enrolled in either group B (telbivudine started at 28 weeks of gestation) or group C (control group without treatment). MTCT was defined as infants who were positive for serum hepatitis B surface antigen at 7 months after birth. There were 41, 179 and 177 pregnant women (397 infants) enrolled in groups A, B and C, respectively. The HBV DNA load at 28 weeks of gestation and delivery was 1.50 ± 0.62 vs 1.45 ± 0.61, 8.05 ± 0.37 vs 4.24 ± 0.89 and 7.94 ± 0.62 vs 7.86 ± 0.73 log₁₀ IU/mL in groups A, B and C, respectively. The rate of MTCT in group C was 4.60%, which was significantly higher than the rates in groups A and B (0% and 0.6%, respectively) (P = .043). The difference between group A and group B was not significant. The rates of neonatal congenital abnormalities were 2.4%, 0.6% and 2.3% in groups A, B and C, respectively, and there were no significant differences (P = .140). Telbivudine used throughout pregnancy may be safe and effective for mothers and infants, but it may not enhance the efficacy of an HBV MTCT block compared with treatment starting at 28 weeks of gestation (NCT02253485).

Sex- and Dose-Specific Effects of Maternal Bisphenol A Exposure on Pancreatic Islets of First- and Second-Generation Adult Mice Offspring

BACKGROUND

Exposure to the environmental endocrine disruptor bisphenol A (BPA) is ubiquitous and associated with the increased risk of diabetes and obesity. However, the underlying mechanisms remain unknown. We recently demonstrated that perinatal BPA exposure is associated with higher body fat, impaired glucose tolerance, and reduced insulin secretion in first- (F1) and second-generation (F2) C57BL/6J male mice offspring.

OBJECTIVE

We sought to determine the multigenerational effects of maternal bisphenol A exposure on mouse pancreatic islets.

METHODS

Cellular and molecular mechanisms underlying these persistent changes were determined in F1 and F2 adult offspring of F0 mothers exposed to two relevant human exposure levels of BPA (10μg/kg/d-LowerB and 10mg/kg/d-UpperB).

RESULTS

Both doses of BPA significantly impaired insulin secretion in male but not female F1 and F2 offspring. Surprisingly, LowerB and UpperB induced islet inflammation in male F1 offspring that persisted into the next generation. We also observed dose-specific effects of BPA on islets in males. UpperB exposure impaired mitochondrial function, whereas LowerB exposure significantly reduced β-cell mass and increased β-cell death that persisted in the F2 generation. Transcriptome analyses supported these physiologic findings and there were significant dose-specific changes in the expression of genes regulating inflammation and mitochondrial function. Previously we observed increased expression of the critically important β-cell gene, Igf2 in whole F1 embryos. Surprisingly, increased Igf2 expression persisted in the islets of male F1 and F2 offspring and was associated with altered DNA methylation.

CONCLUSION

These findings demonstrate that maternal BPA exposure has dose- and sex-specific effects on pancreatic islets of adult F1 and F2 mice offspring. The transmission of these changes across multiple generations may involve either mitochondrial dysfunction and/or epigenetic modifications. https://doi.org/10.1289/EHP1674.

Estrogen Signaling Contributes to Sex Differences in Macrophage Polarization during Asthma

Allergic asthma is a chronic Th2 inflammation in the lungs that constricts the airways and presents as coughing and wheezing. Asthma mostly affects boys in childhood and women in adulthood, suggesting that shifts in sex hormones alter the course of the disease. Alveolar macrophages have emerged as major mediators of allergic lung inflammation in animal models as well as humans. Whether sex differences exist in macrophage polarization and the molecular mechanism(s) that drive differential responses are not well understood. We found that IL-4-stimulated bone marrow-derived and alveolar macrophages from female mice exhibited greater expression of M2 genes in vitro and after allergen challenge in vivo. Alveolar macrophages from female mice exhibited greater expression of the IL-4Rα and estrogen receptor (ER) α compared with macrophages from male mice following allergen challenge. An ERα-specific agonist enhanced IL-4-induced M2 gene expression in macrophages from both sexes, but more so in macrophages from female mice. Furthermore, IL-4-stimulated macrophages from female mice exhibited more transcriptionally active histone modifications at M2 gene promoters than did macrophages from male mice. We found that supplementation of estrogen into ovariectomized female mice enhanced M2 polarization in vivo upon challenge with allergen and that macrophage-specific deletion of ERα impaired this M2 polarization. The effects of estrogen are long-lasting; bone marrow-derived macrophages from ovariectomized mice implanted with estrogen exhibited enhanced IL-4-induced M2 gene expression compared with macrophages from placebo-implanted littermates. Taken together, our findings suggest that estrogen enhances IL-4-induced M2 gene expression and thereby contributes to sex differences observed in asthma.

Self-renewal and phenotypic conversion are the main physiological responses of macrophages to the endogenous estrogen surge

Beyond the physiology of reproduction, estrogen controls the homeostasis of several tissues. Although macrophages play a key role in tissue remodeling, the interplay with estrogen is still ill defined. Using a transcriptomic approach we first obtained a comprehensive list of genes that are differentially expressed in peritoneal macrophages in response to physiological levels of 17β-estradiol (E₂) injected in intact female mice. Our data also showed the dynamic nature of the macrophage response to E₂ and pointed to specific biological programs induced by the hormone, with cell proliferation, immune response and wound healing being the most prominent functional categories. Indeed, the exogenous administration of E₂ and, more importantly, the endogenous hormonal surge proved to support macrophage proliferation in vivo, as shown by cell cycle gene expression, BrdU incorporation and cell number. Furthermore, E₂ promoted an anti-inflammatory and pro-resolving macrophage phenotype, which converged on the induction of genes related to macrophage alternative activation and on IL-10 expression in vivo. Hormone action was maintained in an experimental model of peritoneal inflammation based on zymosan injection. These findings highlight a direct effect of estrogen on macrophage expansion and phenotypic adaptation in homeostatic conditions and suggest a role for this interplay in inflammatory pathologies.

The immunomodulatory role of the hypothalamus-pituitary-gonad axis: Proximate mechanism for reproduction-immune trade offs?

The present review discusses the communication between the hypothalamic-pituitary-gonad (HPG) axis and the immune system of vertebrates, attempting to situate the HPG-immune interaction into the context of life history trade-offs between reproductive and immune functions. More specifically, (i) we review molecular and cellular interactions between hormones of the HPG axis, and, as far as known, the involved mechanisms on immune functions, (ii) we evaluate whether the HPG-immune crosstalk serves as proximate mechanism mediating reproductive-immune trade-offs, and (iii) we ask whether the nature of the HPG-immune interaction is conserved throughout vertebrate evolution, despite the changes in immune functions, reproductive modes, and life histories. In all vertebrate classes studied so far, HPG hormones have immunomodulatory functions, and indications exist that they contribute to reproduction-immunity resource trade-offs, although the very limited information available for most non-mammalian vertebrates makes it difficult to judge how comparable or different the interactions are. There is good evidence that the HPG-immune crosstalk is part of the proximate mechanisms underlying the reproductive-immune trade-offs of vertebrates, but it is only one factor in a complex network of factors and processes. The fact that the HPG-immune interaction is flexible and can adapt to the functional and physiological requirements of specific life histories. Moreover, the assumption of a relatively fixed pattern of HPG influence on immune functions, with, for example, androgens always leading to immunosuppression and estrogens always being immunoprotective, is probably oversimplified, but the HPG-immune interaction can vary depending on the physiological and envoironmental context. Finally, the HPG-immune interaction is not only driven by resource trade-offs, but additional factors such as, for instance, the evolution of viviparity shape this neuroendocrine-immune relationship.

Effects of xenoestrogens in human M1 and M2 macrophage migration, cytokine release, and estrogen-related signaling pathways

Bisphenol A (BPA), bis(2-ethylhexyl)phthalate (DEHP) and di(n-butyl)phthalate (DBP) are environmental estrogens that have been associated with a wide range of adverse health outcomes for which inflammation has also been hypothesized as a potentially involved mechanism and where macrophages play a central role. This study was carried out to evaluate if xenoestrogen (XE) treatment of classically (M1) or alternatively (M2) activated macrophages could affect their behavior. For this purpose, human peripheral blood monocyte-derived macrophages either unstimulated or activated with lipopolysaccharide (100 ng/mL, M1) or with interleukin (IL) 4 (15 ng/mL, M2) were treated with 17β-estradiol (E₂ ), BPA, DEHP and DBP alone or in combination with selective ERα or ERβ antagonists. Migratory capability, cytokine release, and estrogen-associated signaling pathways were evaluated to assess macrophage function. All tested XEs had a tendency to stimulate M2 migration, an effect that followed the same direction than E₂ . Moreover, all XEs significantly induced IL10 in M1 and decreased IL6 and globally decreased IL10, IL6, TNFα, and IL1β release by M2 macrophages. However, DEHP and DBP significantly increased IL1β release in M1 and M2 macrophages, respectively. Some of the effects described above were shown to be mediated by either ERα or ERβ and were simultaneous to modulation of NF-κB, AP1, JNK, or ERK signaling pathways. We provide new evidence of the effect of XE on macrophage behavior and their mechanisms with relevance to the understanding of the action of environmental chemicals on the immune system and inflammation-associated diseases. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1496-1509, 2016.

Effect of Depot Medoxyprogesterone Acetate on Immune Functions and Inflammatory Markers of HIV-Infected Women

OBJECTIVES

Depot medroxyprogesterone acetate (DMPA) was associated with increased HIV transmission and accelerated disease progression in untreated women. The potential underlying mechanisms include immune modulation. We evaluated the effect of a single DMPA injection on cell-mediated immunity (CMI), T-cell activation, T-cell regulation (Treg), and inflammation in HIV-infected women on combination antiretroviral regimen (cART).

METHODS

Women with HIV plasma RNA ≤ 400 copies per milliliter on stable cART received DMPA and had immunologic and medroxyprogesterone acetate (MPA) measurements at baseline, 4 weeks [peak MPA concentration (Cmax)], and 12 weeks [highest MPA area under the concentration curve].

RESULTS

At baseline, among 24 women with median age of 32 years and 622 CD4(+) cells per microliter, ≥ 68% had HIV, varicella-zoster virus, phytohemagglutinin A and CD3/CD28 CMI measured by lymphocyte proliferation, and/or IFNγ/IL2 dual-color fluorospot. CMI did not significantly change after DMPA administration except for a 1.4-fold increase in IL2/IFNγ varicella-zoster virus fluorospot at week 12. T-cell activation decreased after DMPA administration, reaching statistical significance at week 12 for CD4(+)CD25+%. Treg behaved heterogeneously with an increase in CD8+FOXP3+% at week 4 and a decrease in CD4+IL35+% at week 12. There was a decrease in TGFβ at week 12 and no other changes in plasma biomarkers. Correlation analyses showed that high MPA Cmax and/or area under the concentration curve were significantly associated with increases of IFNγ HIV enzyme-linked ImmunoSpot, CD4+IL35+%, and CD4+TGFβ+% Treg and decreases of plasma IL10 from baseline to weeks 4 and/or 12.

CONCLUSIONS

A single dose of DMPA did not have immune-suppressive or pro-inflammatory effects in HIV-infected women on cART. Additional studies need to assess the effect of multiple doses.

The Immune System Is a Natural Target for Estrogen Action: Opposing Effects of Estrogen in Two Prototypical Autoimmune Diseases

Analogous to other physiological systems, the immune system also demonstrates remarkable sex differences. Although the reasons for sex differences in immune responses are not precisely understood, it potentially involves differences in sex hormones (estrogens, androgens, and differential sex hormone receptor-mediated events), X-chromosomes, microbiome, epigenetics among others. Overall, females tend to have more responsive and robust immune system compared to their male counterparts. It is therefore not surprising that females respond more aggressively to self-antigens and are more susceptible to autoimmune diseases. Female hormone (estrogen or 17β-estradiol) can potentially act on all cellular subsets of the immune system through estrogen receptor-dependent and -independent mechanisms. This minireview highlights differential expression of estrogen receptors on immune cells, major estrogen-mediated signaling pathways, and their effect on immune cells. Since estrogen has varied effects in female-predominant autoimmune diseases such as multiple sclerosis and systemic lupus erythematosus, we will mechanistically postulate the potential differential role of estrogen in these chronic debilitating diseases.

Estrogen Signaling Modulates Allergic Inflammation and Contributes to Sex Differences in Asthma

Asthma is a chronic airway inflammatory disease that affects ~300 million people worldwide. It is characterized by airway constriction that leads to wheezing, coughing, and shortness of breath. The most common treatments are corticosteroids and β2-adrenergic receptor antagonists, which target inflammation and airway smooth muscle constriction, respectively. The incidence and severity of asthma is greater in women than in men, and women are more prone to develop corticosteroid-resistant or “hard-to-treat” asthma. Puberty, menstruation, pregnancy, menopause, and oral contraceptives are known to contribute to disease outcome in women, suggesting a role for estrogen and other hormones impacting allergic inflammation. Currently, the mechanisms underlying these sex differences are poorly understood, although the effect of sex hormones, such as estrogen, on allergic inflammation is gaining interest. Asthma presents as a heterogeneous disease. In typical Th2-type allergic asthma, interleukin (IL)-4 and IL-13 predominate, driving IgE production and recruitment of eosinophils into the lungs. Chronic Th2-inflammation in the lung results in structural changes and activation of multiple immune cell types, leading to a deterioration of lung function over time. Most immune cells express estrogen receptors (ERα, ERβ, or the membrane-bound G-protein-coupled ER) to varying degrees and can respond to the hormone. Together these receptors have demonstrated the capacity to regulate a spectrum of immune functions, including adhesion, migration, survival, wound healing, and antibody and cytokine production. This review will cover the current understanding of estrogen signaling in allergic inflammation and discuss how this signaling may contribute to sex differences in asthma and allergy.

Sex differences in immune responses to infectious diseases

PURPOSE

The influence of sex hormones is recognized to account for the susceptibility and distinct outcomes of diverse infectious diseases.

METHODS

This review discusses several variables including differences in behavior and exposure to pathogens, genetic, and immunological factors.

CONCLUSION

Understanding sex-based differences in immunity during different infectious diseases is crucial in order to provide optimal disease management for both sexes.

Sex steroid signaling: implications for lung diseases

There is increasing recognition that sex hormones (estrogen, progesterone, and testosterone) have biological and pathophysiological actions in peripheral, non-reproductive organs, including the lung. Clinically, sex differences in the incidence, morbidity and mortality of lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, lung cancer and pulmonary hypertension have been noted, although intrinsic sex differences vs. the roles of sex steroids are still not well-understood. Accordingly, it becomes important to ask the following questions: 1) Which sex steroids are involved? 2) How do they affect different components of the lung under normal circumstances? 3) How does sex steroid signaling change in or contribute to lung disease, and in this regard, are sex steroids detrimental or beneficial? As our understanding of sex steroid signaling in the lung improves, it is important to consider whether such information can be used to develop new therapeutic strategies to target lung diseases, perhaps in both sexes or in a sex-specific manner. In this review, we focus on the basics of sex steroid signaling, and the current state of knowledge regarding how they influence structure and function of specific lung components across the life span and in the context of some important lung diseases. We then summarize the potential for sex steroids as useful biomarkers and therapeutic targets in these lung diseases as a basis for future translational research in the area of gender and individualized medicine.

ERβ and ERα Differentially Regulate NKT and Vγ4+ T-cell Activation and T-regulatory Cell Response in Coxsackievirus B3 Infected Mice

OBJECTIVES

Coxsackievirus B3 (CVB3) induced myocarditis is sex dependent with males developing more severe disease than females. Previous studies had shown that sex-associated hormones determine the sex bias with testosterone and progesterone promoting myocarditis while estrogen (E2) is protective. There are two major estrogen receptors: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). The goal of the current study was to determine the relative role of these receptors to myocarditis susceptibility and the mechanism of their action.

METHODS

Female C57Bl/6 wild-type mice and C57Bl/6 mice deficient in ERα, or ERβ were infected intraperitoneally with 102 plaque forming units CVB3. After 7 days, hearts were evaluated for virus titers by plaque forming assay and myocardial inflammation. Lymphoid cells either from the spleen or infiltrating the heart were characterized by labeling with antibodies including CD4, CD25, FoxP3, IFNγ, IL-4, CD11b, CD1d, Vγ4, TCRβ, or with CD1d-tetramer and evaluated by flow cytometry. To confirm that signaling through distinct estrogen receptors controlled myocarditis susceptibility and T-regulatory cell response, male C57Bl/6 mice were treated with the ERα-specific agonist, propyl pyrazole triol (PPT), ERβ agonist, diarylpropionitrile (DPN), or 17-β-estradiol (E2) as a non-specific estrogen receptor agonist.

RESULTS

Myocarditis, cardiac virus titers, and CD4⁺ Th1 (IFNγ) bias were increased in infected ERαKO and decreased in infected ERβKO mice compared to C57Bl/6 controls. CD4⁺Th1 bias and myocarditis severity correlated inversely with numbers of CD4⁺CD25⁺FoxP3⁺ T regulatory cells which were decreased in ERαKO and increased in ERβKO mice. Increased T-regulatory cells corresponded to a preferential activation of natural killer T (NKT) cells in ERβKO mice. Male C57Bl/6 mice treated with DPN showed increased myocarditis while those treated with PPT and E2 showed decreased myocarditis corresponding to either decreased (DPN) or increased (PPT/E2) T-regulatory cell responses in male C57Bl/6 mice. DPN and PPT treatment had no effect on T-regulatory cell responses in NKT KO or γδKO mice.

CONCLUSION

These results demonstrate that ERα and ERβ both modulated CVB3 myocarditis susceptibility but in opposite directions and that their predominant effect is mediated through their ability to alter NKT and Vγ4⁺ innate T cell responses in the infected host. It is these innate T cells which positively or negatively modulate T-regulatory cell responses.

Estrogen signaling in metabolic inflammation

There is extensive evidence supporting the interference of inflammatory activation with metabolism. Obesity, mainly visceral obesity, is associated with a low-grade inflammatory state, triggered by metabolic surplus where specialized metabolic cells such as adipocytes activate cellular stress initiating and sustaining the inflammatory program. The increasing prevalence of obesity, resulting in increased cardiometabolic risk and precipitating illness such as cardiovascular disease, type 2 diabetes, fatty liver, cirrhosis, and certain types of cancer, constitutes a good example of this association. The metabolic actions of estrogens have been studied extensively and there is also accumulating evidence that estrogens influence immune processes. However, the connection between these two fields of estrogen actions has been underacknowledged since little attention has been drawn towards the possible action of estrogens on the modulation of metabolism through their anti-inflammatory properties. In the present paper, we summarize knowledge on the modification inflammatory processes by estrogens with impact on metabolism and highlight major research questions on the field. Understanding the regulation of metabolic inflammation by estrogens may provide the basis for the development of therapeutic strategies to the management of metabolic dysfunctions.