Estrogen increases nitric-oxide production in human bronchial epithelium

Sex hormones and allergies: exploring the gender differences in immune responses

Allergies are closely associated with sex-related hormonal variations that influence immune function, leading to distinct symptom profiles. Similar sex-based differences are observed in other immune disorders, such as autoimmune diseases. In allergies, women exhibit a higher prevalence of atopic conditions, such as allergic asthma and eczema, in comparison to men. However, age-related changes play a significant role because men have a higher incidence of allergies until puberty, and then comes a switch ratio of prevalence and severity in women. Investigations into the mechanisms of how the hormones influence the development of these diseases are crucial to understanding the molecular, cellular, and pathological aspects. Sex hormones control the reproductive system and have several immuno-modulatory effects affecting immune cells, including T and B cell development, antibody production, lymphoid organ size, and lymphocyte death. Moreover, studies have suggested that female sex hormones amplify memory immune responses, which may lead to an excessive immune response impacting the pathogenesis, airway hyperresponsiveness, inflammation of airways, and mucus production of allergic diseases. The evidence suggests that estrogens enhance immune humoral responses, autoimmunity, mast cell reactivity, and delayed IV allergic reactions, while androgens, progesterone, and glucocorticoids suppress them. This review explores the relationship between sex hormones and allergies, including epidemiological data, experimental findings, and insights from animal models. We discuss the general properties of these hormones, their effects on allergic processes, and clinical observations and therapeutic results. Finally, we describe hypersensitivity reactions to these hormones.

Obesity and hormonal influences on asthma: Mechanisms, management challenges, and emerging therapeutic strategies

Obesity and hormone dysregulation, common comorbidities of asthma, not only influence asthma risk and onset but can also complicate its management. The pathobiologic characteristics of obesity, such as insulin resistance and metabolism alterations, can impact lung function and airway inflammation while highlighting potential opportunities for therapeutic intervention. Likewise, obesity alters immune cell phenotypes and corticosteroid pharmacokinetics. Hormones such as sex hormones, incretins, and thyroid hormones can also affect asthma. This review highlights the mechanisms underlying obesity-related asthma and hormonal pathologies while exploring potential therapeutic strategies and the need for more research and innovative approaches in managing these comorbid conditions.

Sex differences in sociodemographic, clinical, and laboratory variables in childhood asthma: A birth cohort study

BACKGROUND

There are marked sex differences in the prevalence and severity of asthma, both during childhood and adulthood. There is a relative lack of comprehensive studies exploring sexdifferences in pediatric asthma cohorts.

OBJECTIVE

To identify the most relevant sex differences in sociodemographic, clinical, and laboratory variables in a well-characterized large pediatric asthma cohort.

METHODS

We performed a cross-sectional analysis of the Mayo Clinic Olmsted County Birth Cohort. In the full birth cohort, we used a natural language-processing algorithm based on the Predetermined Asthma Criteria for asthma ascertainment. In a stratified random sample of 300 children, we obtained additional pulmonary function tests and laboratory data. We identified the significant sex differences among available sociodemographic, clinical, and laboratory variables.

RESULTS

Boys were more frequently diagnosed with having asthma than girls and were younger at the time of asthma diagnosis. There were no sex differences in relation to socioeconomic status. We identified a male predominance in the presence of a tympanostomy tube and a female predominance in the history of pneumonia. A higher percentage of boys had a forced expiratory volume in 1 second/forced vital capacity ratio less than 0.85. Blood eosinophilia and atopic sensitization were also more common in boys. Finally, boys had higher levels of serum periostin than girls.

CONCLUSION

This study described significant sex differences in a large pediatric asthma cohort. Overall, boys had earlier and more severe asthma than girls. Differences in blood eosinophilia and serum periostin provide insights into possible mechanisms of the sex bias in childhood asthma.

Chinese expert consensus on the diagnosis, treatment, and management of asthma in women across life

Background

The epidemiology and severity of asthma vary by sex and age. The diagnosis, treatment, and management of asthma in female patients are quite challenging. However, there is hitherto no comprehensive and standardized guidance for female patients with asthma.

Methods

Corresponding search strategies were determined based on clinical concerns regarding female asthma. Search terms included "sex hormones and lung development", "sex hormone changes and asthma", "hormones and asthma immune response", "women, asthma", "children, asthma", "puberty, asthma", "menstruation, asthma", "pregnancy, asthma", "lactation, asthma", "menopause, asthma", "obesity, asthma", and "women, refractory, severe asthma". Literature was retrieved from PubMed/Medline, Embase, Cochrane Library, China Biology Medicine disc, China National Knowledge Infrastructure, Wanfang Data with the search date of July 30, 2022 as the last day. This consensus used the Grading of Recommendations Assessment, Development, and Evaluation to evaluate the strength of recommendation and quality of evidence.

Results

We collected basic research results and clinical evidence-based medical data and reviewed the effects of sex hormones, classical genetics, and epigenetics on the clinical presentation and treatment response of female patients with asthma under different environmental effects. Based on that, we formulated this expert consensus on the management of female asthma throughout the life cycle.

Conclusions

This expert consensus on the management of asthma in women throughout the life cycle provides diagnosis, treatment, and research reference for clinical and basic medical practitioners.

Estrogen Receptor-α Exacerbates EGF-Inducing Airway Remodeling and Mucus Production in Bronchial Epithelium of Asthmatics

PURPOSE

Although estrogen receptors (ERs) signal pathways are involved in the pathogenesis and development of asthma, their expressions and effects remain controversial. This study aimed to investigate the expressions of ERα and ERβ as well as their mechanisms in airway remodeling and mucus production in asthma.

METHODS

The expressions of ERα and ERβ in the airway epithelial cells of bronchial biopsies and induced sputum cells were examined by immunohistochemistry. The associations of ERs expressions with airway inflammation and remodeling were evaluated in asthmatic patients. In vitro, the regulations of ERs expressions in human bronchial epithelial cell lines were examined using western blot analysis. The epidermal growth factor (EGF)-mediated ligand-independent activation of ERα and its effect on epithelial-mesenchymal transitions (EMTs) were investigated in asthmatic epithelial cells by western blot, immunofluorescent staining, and quantitative real-time polymerase chain reaction.

RESULTS

ERα and ERβ were expressed on both bronchial epithelial cells and induced sputum cells, and the expressions showed no sex difference. Compared to controls, male asthmatic patients had higher levels of ERα on the bronchial epithelium, and there were cell-specific expressions of ERα and ERβ in induced sputum. The expression of ERα in the airway epithelium was inversely correlated to forced expiratory volume in 1 second (FEV1) % and FEV1/forced vital capacity. Severe asthmatic patients had significantly greater levels of ERα in the airway epithelium than mild-moderate patients. ERα level was positively correlated with the thickness of the subepithelial basement membrane and airway epithelium. In vitro, co-stimulation of interleukin (IL)-4 and EGF increased the expression of ERα and promoted its nuclear translocation. EGF activated the phosphorylation of ERα via extracellular signal-regulated kinase and c-Jun N-terminal kinase pathways. ERα knockdown alleviated EGF-mediated EMTs and mucus production in airway epithelial cells of asthma.

CONCLUSIONS

ERα contributes to asthmatic airway remodeling and mucus production through the EGF-mediated ligand-independent pathway.

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.

Sex Plays a Multifaceted Role in Asthma Pathogenesis

Sex is considered an important risk factor for asthma onset and exacerbation. The prevalence of asthma is higher in boys than in girls during childhood, which shows a reverse trend after puberty—it becomes higher in adult females than in adult males. In addition, asthma severity, characterized by the rate of hospitalization and relapse after discharge from the emergency department, is higher in female patients. Basic research indicates that female sex hormones enhance type 2 adaptive immune responses, and male sex hormones negatively regulate type 2 innate immune responses. However, whether hormone replacement therapy in postmenopausal women increases the risk of current asthma and asthma onset remains controversial in clinical settings. Recently, sex has also been shown to influence the pathophysiology of asthma in its relationship with genetic or other environmental factors, which modulate asthmatic immune responses in the airway mucosa. In this narrative review, we highlight the role of sex in the continuity of the asthmatic immune response from sensing allergens to Th2 cell activation based on our own data. In addition, we elucidate the interactive role of sex with genetic or environmental factors in asthma exacerbation in women.

Role of Sex Hormones at Different Physiobiological Conditions and Therapeutic Potential in MBD2 Mediated Severe Asthma

Sex hormone has become a “hot topic” to evaluate the hormonal therapeutic potential in severe asthma. Th17 cell is one of the main influencing factors involved in the pathogenesis of severe asthma, hence also called as kernel of severe asthma, and Th17 subtype of non-T2 asthma is less responsive (resistance) to inhaled corticosteroid (ICS), so severe in nature. Methyl-CpG binding domain protein 2 (MBD2) is overexpressed and regulates the Th17 differentiation, showing the possibility of therapeutic target in treating Th17 mediated severe asthma. Sex hormone fluctuates at the different physiobiological conditions of the human body and affects the asthma pathobiology showing its role in asthma prevalence, severity, remission, and therapy. This review briefly overviews the sex hormones, their influence in asthma at the different physiobiological conditions of human body, and MBD2 severe asthma connection with the possible therapeutic potential of sex steroids in MBD2 mediated Th17 predominant severe asthma. Male sex hormone tends to show a beneficial effect and possibly downregulates the expression of Th17 cells via regulating MBD2 through a mechanism distinct from corticosteroid treatment and guides us towards discovery of new therapeutic agent, reduces the asthma-related complications, and promotes long-term survival by lowering the risk of therapy-resistant issues of old age severe asthma.

Benefits of Airway Androgen Receptor Expression in Human Asthma

Rationale: Androgens are potentially beneficial in asthma, but AR (androgen receptor) has not been studied in human airways.Objectives: To measure whether AR and its ligands are associated with human asthma outcomes.Methods: We compared the effects of AR expression on lung function, symptom scores, and fractional exhaled nitric oxide (Fe_NO) in adults enrolled in SARP (Severe Asthma Research Program). The impact of sex and of androgens on asthma outcomes was also evaluated in the SARP with validation studies in the Cleveland Clinic Health System and the NHANES (U.S. National Health and Nutrition Examination Survey).Measurements and Main Results: In SARP (n = 128), AR gene expression from bronchoscopic epithelial brushings was positively associated with both FEV₁/FVC ratio (R² = 0.135, P = 0.0002) and the total Asthma Quality of Life Questionnaire score (R² = 0.056, P = 0.016) and was negatively associated with Fe_NO (R² = 0.178, P = 9.8 × 10^-6) and NOS2 (nitric oxide synthase gene) expression (R² = 0.281, P = 1.2 × 10^-10). In SARP (n = 1,659), the Cleveland Clinic Health System (n = 32,527), and the NHANES (n = 2,629), women had more asthma exacerbations and emergency department visits than men. The levels of the AR ligand precursor dehydroepiandrosterone sulfate correlated positively with the FEV₁ in both women and men.Conclusions: Higher bronchial AR expression and higher androgen levels are associated with better lung function, fewer symptoms, and a lower Fe_NO in human asthma. The role of androgens should be considered in asthma management.

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.

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.

Sex-Steroid Signaling in Lung Diseases and Inflammation

Sex/gender difference exists in the physiology of multiple organs. Recent epidemiological reports suggest the influence of sex-steroids in modulating a wide variety of disease conditions. Sex-based discrepancies have been reported in pulmonary physiology and various chronic inflammatory responses associated with lung diseases like asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and rare lung diseases. Notably, emerging clinical evidence suggests that several respiratory diseases affect women to a greater degree, with increased severity and prevalence than men. Although sex-specific differences in various lung diseases are evident, such differences are inherent to sex-steroids, which are major biological variables in men and women who play a central role to control these differences. The focus of this chapter is to comprehend the sex-steroid biology in inflammatory lung diseases and to understand the mechanistic role of sex-steroids signaling in regulating these diseases. Exploring the roles of sex-steroid signaling in the regulation of lung diseases and inflammation is crucial for the development of novel and effective therapy. Overall, we will illustrate the importance of differential sex-steroid signaling in lung diseases and their possible clinical implications for the development of complementary and alternative medicine to treat lung diseases.

Androgen receptor activation alleviates airway hyperresponsiveness, inflammation, and remodeling in a murine model of asthma

Epidemiological studies demonstrate an apparent sex-based difference in the prevalence of asthma, with a higher risk in boys than girls, which is reversed postpuberty, where women become more prone to asthma than men, suggesting a plausible beneficial role for male hormones, especially androgens as a regulator of pathophysiology in asthmatic lungs. Using a murine model of asthma developed with mixed allergen (MA) challenge, we report a significant change in airway hyperresponsiveness (AHR), as demonstrated by increased thickness of epithelial and airway smooth muscle layers and collagen deposition, as well as Th2/Th17-biased inflammation in the airways of non-gonadectomized (non-GDX) and gonadectomized (GDX) male mice. Here, compared with non-GDX mice, MA-induced AHR and inflammatory changes were more prominent in GDX mice. Activation of androgen receptor (AR) using 5α-dihydrotestosterone (5α-DHT, AR agonist) resulted in decreased Th2/Th17 inflammation and remodeling-associated changes, resulting in improved lung function compared with MA alone challenged mice, especially in GDX mice. These changes were not observed with Flutamide (Flut, AR antagonist). Overall, we show that AR exerts a significant and beneficial role in asthma by regulating AHR and inflammation.

Is COVID-19 Gender-sensitive?

While clinical characteristics exhibit that susceptibility to COVID-19 infection is equally likely between males and females, clinical outcomes show that males experience both a higher severity and fatality for COVID-19 infection than females. This review examines the evidence for these sex and gender differences and aims to illustrate possible mechanisms behind such sensitivity. Successful entry of SARS-CoV-2 into the body is dependent on the angiotensin-converting enzyme 2 (ACE2) receptor and the transmembrane protease serine 2 (TMPRSS2). Thus, sex-based differences in the expression of the ACE2 receptor and TMPRSS2 may explain the disparities in COVID-19 severity and fatality. Furthermore, these disparities may also be attributed to sex-based difference in immunological responses. Finally, the differences in clinical outcomes of COVID-19 infections between men and women may be due to gendered differences in behaviors, such as smoking, and prevalence to comorbidities. An understanding of the sex and gender sensitivities of COVID-19 infection is a necessary component towards the creation of effective treatment options and therapies for the virus. Graphical abstract.

The impact of 17β-estradiol and progesterone therapy on peripheral blood mononuclear cells of asthmatic patients

There is a significant fluctuation in clinical symptoms of asthmatic females during their life course, suggesting that the reproductive status and the level of sex hormones may affect the development of asthma and its exacerbation. In this study, we aimed to assess the biological effects of 17β-estradiol (E2) and progesterone (P4), alone or in combination form, on the transcription factors and production of cytokines in peripheral blood mononuclear cells (PBMCs). PBMCs of the mild-to-moderate asthmatic patients and healthy controls (HCs) were treated with equivalent serum levels of E2 or P4 maintained during hormone replacement therapy (HRT). The expression levels of T-bet, GATA-3, RORγt, PU.1, and Foxp3 were assessed by quantitative PCR. We also measured the concentration of IL-4, IL-9, IL-10, IFN-γ, and TGF-β in cell culture supernatants using ELISA. IL-4 production and GATA-3 expression levels slightly increased when asthmatic PBMCs were treated with E2 (p < 0.01), P4 (p < 0.01), or E2 + P4 (p < 0.001) compared to the untreated cells. IL-9 secretion (p < 0.001) and PU.1 gene expression levels (p < 0.05) were slightly higher in asthmatic patients' PBMCs before treatment but hormone therapy did not affect the level of them. Although the untreated asthmatic PBMCs produced a lower amount of IFN-γ compared to HCs (p < 0.01), hormone treatment did not affect the levels of IFN-γ secretion in patient groups. Moreover, we did not observe any significant changes in IL-10 and TGF-β secretion in the supernatant of hormone treated cells. We found that the common applied HRT may faintly increase GATA-3 expression and IL-4 production levels in PBMCs of asthmatic patients and can slightly increase asthma severity.

Bitter taste receptors stimulate phagocytosis in human macrophages through calcium, nitric oxide, and cyclic-GMP signaling

Bitter taste receptors (T2Rs) are GPCRs involved in detection of bitter compounds by type 2 taste cells of the tongue, but are also expressed in other tissues throughout the body, including the airways, gastrointestinal tract, and brain. These T2Rs can be activated by several bacterial products and regulate innate immune responses in several cell types. Expression of T2Rs has been demonstrated in immune cells like neutrophils; however, the molecular details of their signaling are unknown. We examined mechanisms of T2R signaling in primary human monocyte-derived unprimed (M0) macrophages (M[Formula: see text]s) using live cell imaging techniques. Known bitter compounds and bacterial T2R agonists activated low-level calcium signals through a pertussis toxin (PTX)-sensitive, phospholipase C-dependent, and inositol trisphosphate receptor-dependent calcium release pathway. These calcium signals activated low-level nitric oxide (NO) production via endothelial and neuronal NO synthase (NOS) isoforms. NO production increased cellular cGMP and enhanced acute phagocytosis ~ threefold over 30-60 min via protein kinase G. In parallel with calcium elevation, T2R activation lowered cAMP, also through a PTX-sensitive pathway. The cAMP decrease also contributed to enhanced phagocytosis. Moreover, a co-culture model with airway epithelial cells demonstrated that NO produced by epithelial cells can also acutely enhance M[Formula: see text] phagocytosis. Together, these data define M[Formula: see text] T2R signal transduction and support an immune recognition role for T2Rs in M[Formula: see text] cell physiology.

[Woman's asthma throughout life: Towards a personalized management?]

In a woman's life, asthma can affect her in a variety of ways, with the onset of premenstrual asthma currently under-diagnosed. It is estimated that about 20% of women with asthma have premenstrual asthma, which is more common in patients with severe asthma. Women with asthma are at high risk of exacerbations and of severe asthma. Asthma is the most common chronic disease during pregnancy with potential maternal and foetal complications. Asthma medications are safe for the foetus and it is essential to continue pre-existing treatment and adapt it to the progress of asthma during the pregnancy. Sex steroids modulate the structure and function of bronchial and immune cells. Understanding their role in asthma pathogenesis is complicated by the ambivalent effects of bronchodilating and pro-inflammatory oestrogens as well as the diversity of response to their association with progesterone. Menopausal asthma is a clinical entity and is part of one of the phenotypes of severe non-allergic and low steroid-sensitive asthma. Targeted assessment of the domestic and professional environment allows optimization of asthma management.

Caveolae, caveolin-1 and lung diseases of aging

INTRODUCTION

Flask-shaped plasma membrane (PM) invaginations called caveolae and their constitutive caveolin and cavin proteins regulate cellular function via plasma membrane and intracellular signal transduction pathways. Caveolae are present in a variety of cells in the lung including airway smooth muscle (ASM) where they interact with other proteins, receptors, and ion channels and thereby have the potential to affect both normal and disease processes such as inflammation, contractility, and fibrosis. Given their involvement in cell signaling, caveolae may play important roles in mediating and modulating aging processes, and contribute to lung diseases of aging. Areas covered: This review provides a broad overview of the current state of knowledge regarding caveolae and their constituent proteins in lung diseases in the elderly and identifies potential mechanisms that can be targeted for future therapies. Expert Commentary: Caveolin-1 may play a protective role in lung disease. What is less clear is whether altered caveolin-1 with aging is a natural process, or a biomarker of disease progression in the elderly.

Knob protein enhances epithelial barrier integrity and attenuates airway inflammation

BACKGROUND

Altered epithelial physical and functional barrier properties along with TH1/TH2 immune dysregulation are features of allergic asthma. Regulation of junction proteins to improve barrier function of airway epithelial cells has the potential for alleviation of allergic airway inflammation.

OBJECTIVE

We sought to determine the immunomodulatory effect of knob protein of the adenoviral capsid on allergic asthma and to investigate its mechanism of action on airway epithelial junction proteins and barrier function.

METHODS

Airway inflammation, including junction protein expression, was evaluated in allergen-challenged mice with and without treatment with knob. Human bronchial epithelial cells were exposed to knob, and its effects on expression of junction proteins and barrier integrity were determined.

RESULTS

Administration of knob to allergen-challenged mice suppressed airway inflammation (eosinophilia, airway hyperresponsiveness, and IL-5 levels) and prevented allergen-induced loss of airway epithelial occludin and E-cadherin expression. Additionally, knob decreased expression of TH2-promoting inflammatory mediators, specifically IL-33, by murine lung epithelial cells. At a cellular level, treatment of human bronchial epithelial cells with knob activated c-Jun N-terminal kinase, increased expression of occludin and E-cadherin, and enhanced epithelial barrier integrity.

CONCLUSION

Increased expression of junction proteins mediated by knob leading to enhanced epithelial barrier function might mitigate the allergen-induced airway inflammatory response, including asthma.

Studying allergic inflammation and spirometry over menstrual cycles in well-controlled asthmatic women: Changes in progesterone and estradiol affect neither FENO levels nor lung function

It has been reported that female sex hormones influence on allergic inflammation and ventilation parameters in asthma but conclusions drawn by different researchers are divergent. The aim of our study was to assess the impact of progesterone (Pg) and estradiol (E) on the dynamics of allergic inflammation and spirometry test results in regularly menstruating women with stable allergic asthma. 13 women (28 days menstrual cycle), aged 18-45, taking no hormonal contraceptives, with mild and moderate asthma, without reported exacerbations at the near-ovulation and/or menstruation time, were monitored during two consecutive menstrual cycles. They had 4 visits per cycle (the first day of menstruation was assumed to be day 1 of the cycle; visits were carried out on days: 3-4, 10-11, 13-14 and 23-24). At each visit asthma symptoms, asthma control test (ACT) results, asthma treatment, fractioned nitric oxide (FENO) levels, spirometry test results, Pg and E, levels were analyzed. As a result of the study, no essential variability in FENO values and ventilation parameters' values in the course of menstruation cycle were observed. Negative correlation between FENO values and Pg concentrations was demonstrated (r = 0.27), but no correlation between FENO values and E levels was shown. No relationship between the ACT values and ventilation parameters and the levels of the sex hormones under investigation was detected. We conclude that changing levels of estradiol and progesterone (regardless of the negative correlation of progesterone and FENO values) affect neither the dynamics of allergic inflammation nor pulmonary function in women with stable allergic mild/moderate asthma.

Differential Expression of Estrogen Receptor Variants in Response to Inflammation Signals in Human Airway Smooth Muscle

The prevalence of asthma is higher in pre-pubescent and aging males, and in post-pubertal females, strongly indicating that sex steroids (especially estrogen) may be an important modulator in lung disease. We recently demonstrated that airway smooth muscle (ASM) expresses both alpha and beta forms of the estrogen receptor (ERα and ERβ) in males and females, and that these receptors regulate intracellular [Ca²⁺ ] and ASM contractility. Although both ERα and ERβ have multiple splice variants, it is unclear if and how the expression of these variants is modulated under conditions such as chronic inflammation/asthma. In order to test the hypothesis that the differential expression of ERα and ERβ variants contributes to the pathogenesis of asthma, we profiled the expression of various ERα and ERβ genes in asthmatic and inflamed (TNFα- or IL-13-treated) ASM. Gene expression was assessed at both the mRNA and protein levels in asthmatic ASM cells or non-asthmatic cells treated with TNFα (20 ng/ml) or IL-13 (50 ng/ml). We observed marked variation in the expression of ER isoforms in response to inflammatory stimuli, and in non-asthmatic versus asthmatic ASM. Changes in protein levels of ERα and ERβ corresponded with the observed differential mRNA patterns. Pharmacological studies implicate cytosolic (p42/44 MAPK and PI3 K) and nuclear (NFκB, STAT6, and AP-1) signaling pathways as putative mechanisms that mediate and/or regulate effects of inflammation on ER expression. We conclude that variations in ASM ER expression profiles occur with inflammation and that ER variants could contribute to estrogen signaling in airway diseases such as asthma. J. Cell. Physiol. 232: 1754-1760, 2017. © 2016 Wiley Periodicals, Inc.

Association between asthma and female sex hormones

CONTEXT AND OBJECTIVE:

The relationship between sex hormones and asthma has been evaluated in several studies. The aim of this review article was to investigate the association between asthma and female sex hormones, under different conditions (premenstrual asthma, use of oral contraceptives, menopause, hormone replacement therapy and pregnancy).

DESIGN AND SETTING:

Narrative review of the medical literature, Universidade Federal do Tocantins (UFT) and Universidade Federal de São Paulo (Unifesp).

METHODS:

We searched the CAPES journal portal, a Brazilian platform that provides access to articles in the MEDLINE, PubMed, SciELO, and LILACS databases. The following keywords were used based on Medical Subject Headings: asthma, sex hormones, women and use of oral contraceptives.

RESULTS:

The associations between sex hormones and asthma remain obscure. In adults, asthma is more common in women than in men. In addition, mortality due to asthma is significantly higher among females. The immune system is influenced by sex hormones: either because progesterone stimulates progesterone-induced blocking factor and Th2 cytokines or because contraceptives derived from progesterone and estrogen stimulate the transcription factor GATA-3.

CONCLUSIONS:

The associations between asthma and female sex hormones remain obscure. We speculate that estrogen fluctuations are responsible for asthma exacerbations that occur in women. Because of the anti-inflammatory action of estrogen, it decreases TNF-α production, interferon-γ expression and NK cell activity. We suggest that further studies that highlight the underlying physiopathological mechanisms contributing towards these interactions should be conducted.

Important non-disease-related determinants of exhaled nitric oxide levels in mild asthma - results from the Swedish GA(2) LEN study

BACKGROUND

Fractional exhaled nitric oxide (FeNO) has a potential clinical role in asthma management. Constitutive factors such as age, height and gender, as well as individual characteristics, such as IgE sensitization and smoking, affect the levels of FeNO in population-based studies. However, their effect on FeNO in subjects with asthma has been scarcely studied.

OBJECTIVE

To study the effects on FeNO of these commonly regarded determinants, as demonstrated in healthy subjects, as well as menarche age and parental smoking, in a population of asthmatics.

MATERIAL AND METHODS

Fractional exhaled nitric oxide was measured in 557 subjects with asthma from the Swedish GA(2) LEN study. Allergic sensitization was assessed by skin prick tests to most common aeroallergens. Upper airway comorbidities, smoking habits, smoking exposure during childhood and hormonal status (for women) were questionnaire-assessed.

RESULTS

Male gender (P < 0.001), greater height (P < 0.001) and sensitization to both perennial allergens and pollen (P < 0.001) are related to higher FeNO levels. Current smoking (P < 0.001) and having both parents smoking during childhood, vs. having neither (P < 0.001) or only one parent smoking (P = 0.002), are related to lower FeNO. Women with menarche between 9 and 11 years of age had lower FeNO than those with menarche between 12 and 14 years of age (P = 0.03) or 15 and 17 years of age (P = 0.003).

CONCLUSIONS AND CLINICAL RELEVANCE

Interpreting FeNO levels in clinical practice is complex, and constitutional determinants, as well as smoking and IgE sensitisation, are of importance in asthmatic subjects and should be accounted for when interpreting FeNO levels. Furthermore, menarche age and parental smoking during childhood and their effects on lowering FeNO deserve further studies.

Sexual Dimorphism in the Regulation of Estrogen, Progesterone, and Androgen Receptors by Sex Steroids in the Rat Airway Smooth Muscle Cells

The role of sex hormones in lung is known. The three main sex steroid receptors, estrogen, progesterone, and androgen, have not been sufficiently studied in airway smooth muscle cells (ASMC), and the sex hormone regulation on these receptors is unknown. We examined the presence and regulation of sex hormone receptors in female and male rat ASMC by Western blotting and flow cytometry. Gonadectomized rats were treated with 17β-estradiol, progesterone, 17β-estradiol + progesterone, or testosterone. ASMC were enzymatically isolated from tracheas and bronchi. The experiments were performed with double staining flow cytometry (anti-α-actin smooth muscle and antibodies to each hormone receptor). ERα, ERβ, tPR, and AR were detected in females or males. ERα was upregulated by E2 and T and downregulated by P4 in females; in males, ERα was downregulated by P4, E + P, and T. ERβ was downregulated by each treatment in females, and only by E + P and T in males. tPR was downregulated by P4, E + P, and T in females. No hormonal regulation was observed in male receptors. AR was downregulated in males treated with E + P and T. We have shown the occurrence of sex hormone receptors in ASMC and their regulation by the sex hormones in female and male rats.

Sex Steroids Influence Brain-Derived Neurotropic Factor Secretion From Human Airway Smooth Muscle Cells

Brain derived neurotropic factor (BDNF) is emerging as an important player in airway inflammation, remodeling, and hyperreactivity. Separately, there is increasing evidence that sex hormones contribute to pathophysiology in the lung. BDNF and sex steroid signaling are thought to be intricately linked in the brain. There is currently little information on BDNF and sex steroid interactions in the airway but is relevant to understanding growth factor signaling in the context of asthma in men versus women. In this study, we assessed the effect of sex steroids on BDNF expression and secretion in human airway smooth muscle (ASM). Human ASM was treated with estrogen (E2 ) or testosterone (T, 10 nM each) and intracellular BDNF and secreted BDNF measured. E2 and T significantly reduced secretion of BDNF; effects prevented by estrogen and androgen receptor inhibitor, ICI 182,780 (1 μM), and flutamide (10 μM), respectively. Interestingly, no significant changes were observed in intracellular BDNF mRNA or protein expression. High affinity BDNF receptor, TrkB, was not altered by E2 or T. E2 (but not T) significantly increased intracellular cyclic AMP levels. Notably, Epac1 and Epac2 expression were significantly reduced by E2 and T. Furthermore, SNARE complex protein SNAP25 was decreased. Overall, these novel data suggest that physiologically relevant concentrations of E2 or T inhibit BDNF secretion in human ASM, suggesting a potential interaction of sex steroids with BDNF in the airway that is different from brain. The relevance of sex steroid-BDNF interactions may lie in their overall contribution to airway diseases such as asthma.

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 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.

Acute effects of estradiol on lung inflammation due to intestinal ischemic insult in male rats

Intestinal ischemia and reperfusion (intestinal I/R) causes acute lung inflammation that is characterized by leukocyte migration, increased lung microvascular permeability, and, in severe forms, noncardiogenic pulmonary edema and acute respiratory distress syndrome. Female sex hormones interfere with immune response, and experimental and clinical evidence shows that females are more resistant than males to organ injury caused by gut trauma. To reduce the lung inflammation caused by intestinal I/R, we have acutely treated male rats with estradiol. Intestinal I/R was performed by the clamping (45 min) of the superior mesenteric artery (SMA), followed by 2 h of intestinal reperfusion (unclamping SMA). Groups of rats received 17β estradiol (E2, 280 µg/kg, i.v., single dose) 30 min after the SMA occlusion (ischemia period) or 1 h after the unclamping of SMA (reperfusion period). Leukocytes influx into the lung and microvascular leakage were assessed by lung myeloperoxidase activity and Evans blue dye extravasation, respectively. The lung expression of adhesion molecules (intercellular adhesion molecule 1, platelet endothelial cell adhesion molecule 1, and vascular cell adhesion molecule [VCAM]) was evaluated by immunohistochemistry. Interleukin 1β (IL-1β), IL-10, and NOx concentrations were quantified in supernatants of cultured lung tissue. We have found that intestinal I/R increased the lung myeloperoxidase activity and Evans blue dye extravasation, which were reduced by treatment of rats with E2. Intestinal I/R increased ICAM-1 expression only, and it was decreased by E2 treatment. However, E2 treatment reduced the basal expression of platelet endothelial cell adhesion molecule 1. E2 treatment during intestinal ischemia was effective to reduce the levels of IL-10 and IL-1β in explant supernatant, but only IL-10 levels were reduced by E2 at reperfusion phase. The treatment with E2 did not affect NOx concentration. Taken together, our data suggest that estradiol modulates the lung inflammatory response induced by lung injury, likely by acute effects. Thus, acute estradiol treatment could be considered as a potential therapeutic agent in ischemic events.

Airway smooth muscle in airway reactivity and remodeling: what have we learned?

It is now established that airway smooth muscle (ASM) has roles in determining airway structure and function, well beyond that as the major contractile element. Indeed, changes in ASM function are central to the manifestation of allergic, inflammatory, and fibrotic airway diseases in both children and adults, as well as to airway responses to local and environmental exposures. Emerging evidence points to novel signaling mechanisms within ASM cells of different species that serve to control diverse features, including 1) [Ca(2+)]i contractility and relaxation, 2) cell proliferation and apoptosis, 3) production and modulation of extracellular components, and 4) release of pro- vs. anti-inflammatory mediators and factors that regulate immunity as well as the function of other airway cell types, such as epithelium, fibroblasts, and nerves. These diverse effects of ASM "activity" result in modulation of bronchoconstriction vs. bronchodilation relevant to airway hyperresponsiveness, airway thickening, and fibrosis that influence compliance. This perspective highlights recent discoveries that reveal the central role of ASM in this regard and helps set the stage for future research toward understanding the pathways regulating ASM and, in turn, the influence of ASM on airway structure and function. Such exploration is key to development of novel therapeutic strategies that influence the pathophysiology of diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis.

A network-based systematic study for the mechanism of the treatment of zhengs related to cough variant asthma

Traditional Chinese medicine (TCM) has shown significant efficacy in the treatment of cough variant asthma (CVA), a special type of asthma. However, there is shortage of explanations for relevant mechanism of treatment. As Zhengs differentiation is a critical concept in TCM, it is necessary to explain the mechanism of treatment of Zhengs. Based on TCM clinical cases, this study illustrated the mechanism of the treatment of three remarkably relevant Zhengs for CVA: “FengXieFanFei,” “FeiQiShiXuan”, and “QiDaoLuanJi.” To achieve this goal, five steps were carried out: (1) determining feature Zhengs and corresponding key herbs of CVA by analyses of clinical cases; (2) finding out potential targets of the key herbs and clustering them based on their functional annotations; (3) constructing an ingredient-herb network and an ingredient network; (4) identifying modules of the ingredient network; (5) illustrating the mechanism of the treatment by further mining the latent biological implications within each module. The systematic study reveals that the treatment of “FengXieFanFei,” “FeiQiShiXuan,” and “QiDaoLuanJi” has effects on the regulation of multiple bioprocesses by herbs containing different ingredients with functions of steroid metabolism regulation, airway inflammation, and ion conduction and transportation. This network-based systematic study will be a good way to boost the scientific understanding of mechanism of the treatment of Zhengs.

Estrogen replacement therapy and asthma

A growing body of clinical and experimental evidence indicates that female sex hormones, particularly estrogen, have significant effects on normal airway function as well as on respiratory disorders, such as asthma. These effects are very complex and are exerted at several levels, directly on airway reactivity or indirectly through regulation of the immune and inflammatory responses in the lung. They can have relevant clinical implications not only according to the phases of the reproductive life in women, but also in relation to the therapeutical administration of estrogen, as in the case of menopausal hormone therapy. Clinical evidence suggests that administration of estrogen to menopausal women is associated with increased rates of newly diagnosed asthma. Conversely, functional studies show that estrogen can improve objective indexes of respiratory functionality.

Sex and race factors in early-onset COPD

PURPOSE OF REVIEW

Unlike other major diseases, mortality for chronic obstructive pulmonary disease (COPD) continues to increase. In recent years, COPD has evolved to increasingly affect women, minorities, and individuals from low socioeconomic groups. In women and African-Americans, evidence exists supporting the earlier development of COPD after less lifetime smoking. This review highlights new information on racial and sex differences in COPD.

RECENT FINDINGS

Sex and related hormonal changes affect T-cell phenotypes, immunity, and smoking-related metabolism of toxic intermediate metabolites. Alterations in the bronchoalveolar lavage proteome of women, but not of men, have allowed the differentiation of healthy female smokers from smokers with COPD. Sex significantly influences levels of inflammatory cytokines and correlates with different clinical and physiological parameters in female COPD patients. African-Americans with COPD are younger, smoke less, are more likely to currently smoke, and have worse health-related quality of life (QOL). African-Americans are more likely to report hospitalized exacerbations that impact QOL. African-Americans with COPD and asthma are nearly four times more likely to experience exacerbations.

SUMMARY

There are sex-specific and race-related differences in the manifestation of COPD. These differences warrant further physiologic, biologic, and genetic investigations.

Estrogen effects in allergy and asthma

PURPOSE OF REVIEW

Asthma prevalence and severity are greater in women than in men, and mounting evidence suggests this is in part related to female steroid sex hormones. Of these, estrogen has been the subject of much study. This review highlights recent research exploring the effects of estrogen in allergic disease.

RECENT FINDINGS

Estrogen receptors are found on numerous immunoregulatory cells and estrogen's actions skew immune responses toward allergy. It may act directly to create deleterious effects in asthma, or indirectly via modulation of various pathways including secretory leukoprotease inhibitor, transient receptor potential vanilloid type 1 ion channel and nitric oxide production to exert effects on lung mechanics and inflammation. Not only do endogenous estrogens appear to play a role, but environmental estrogens have also been implicated. Environmental estrogens (xenoestrogens) including bisphenol A and phthalates enhance allergic sensitization in animal models and may enhance development of atopic disorders like asthma in humans.

SUMMARY

Estrogen's role in allergic disease remains complex. As allergic diseases continue to increase in prevalence and affect women disproportionately, gaining a fuller understanding of its effects in these disorders will be essential. Of particular importance may be effects of xenoestrogens on allergic disease.

Caveolin-1 knockout mice exhibit airway hyperreactivity

Caveolae are flask-shaped plasma membrane invaginations expressing the scaffolding caveolin proteins. Although caveolins have been found in endothelium and epithelium (where they regulate nitric oxide synthase activity), their role in smooth muscle is still under investigation. We and others have previously shown that caveolae of human airway smooth muscle (ASM), which express caveolin-1, contain Ca(2+) and force regulatory proteins and are involved in mediating the effects of inflammatory cytokines such as TNF-α on intracellular Ca(2+) concentration responses to agonist. Accordingly, we tested the hypothesis that in vivo, absence of caveolin-1 leads to reduced airway hyperresponsiveness, using a knockout (KO) (Cav1 KO) mouse and an ovalbumin-sensitized/challenged (OVA) model of allergic airway hyperresponsiveness. Surprisingly, airway responsiveness to methacholine, tested by use of a FlexiVent system, was increased in Cav1 KO control (CTL) as well as KO OVA mice, which could not be explained by a blunted immune response to OVA. In ASM of wild-type (WT) OVA mice, expression of caveolin-1, the caveolar adapter proteins cavins 1-3, and caveolae-associated Ca(2+) and force regulatory proteins such as Orai1 and RhoA were all increased, effects absent in Cav1 KO CTL and OVA mice. However, as with WT OVA, both CTL and OVA Cav1 KO airways showed signs of enhanced remodeling, with high expression of proliferation markers and increased collagen. Separately, epithelial cells from airways of all three groups displayed lower endothelial but higher inducible nitric oxide synthase and arginase expression. Arginase activity was also increased in these three groups, and the inhibitor nor-NOHA (N-omega-nor-l-arginine) enhanced sensitivity of isolated tracheal rings to ACh, especially in Cav1 KO mice. On the basis of these data disproving our original hypothesis, we conclude that caveolin-1 has complex effects on ASM vs. epithelium, resulting in airway hyperreactivity in vivo mediated by altered airway remodeling and bronchodilation.

Sex differences and sex steroids in lung health and disease

Sex differences in the biology of different organ systems and the influence of sex hormones in modulating health and disease are increasingly relevant in clinical and research areas. Although work has focused on sex differences and sex hormones in cardiovascular, musculoskeletal, and neuronal systems, there is now increasing clinical evidence for sex differences in incidence, morbidity, and mortality of lung diseases including allergic diseases (such as asthma), chronic obstructive pulmonary disease, pulmonary fibrosis, lung cancer, as well as pulmonary hypertension. Whether such differences are inherent and/or whether sex steroids play a role in modulating these differences is currently under investigation. The purpose of this review is to define sex differences in lung structure/function under normal and specific disease states, with exploration of whether and how sex hormone signaling mechanisms may explain these clinical observations. Focusing on adult age groups, the review addresses the following: 1) inherent sex differences in lung anatomy and physiology; 2) the importance of certain time points in life such as puberty, pregnancy, menopause, and aging; 3) expression and signaling of sex steroid receptors under normal vs. disease states; 4) potential interplay between different sex steroids; 5) the question of whether sex steroids are beneficial or detrimental to the lung; and 6) the potential use of sex steroid signaling as biomarkers and therapeutic avenues in lung diseases. The importance of focusing on sex differences and sex steroids in the lung lies in the increasing incidence of lung diseases in women and the need to address lung diseases across the life span.