Steady-state estradiol triggers a unique innate immune response to allergen resulting in increased airway resistance

17β-estradiol induces hyperresponsiveness in guinea pig airway smooth muscle by inhibiting the plasma membrane Ca2+-ATPase

High serum estrogen concentrations are associated with asthma development and severity, suggesting a link between estradiol and airway hyperresponsiveness (AHR). 17β-estradiol (E2) has non-genomic effects via Ca2+ regulatory mechanisms; however, its effect on the plasma membrane Ca2+-ATPases (PMCA1 and 4) and sarcoplasmic reticulum Ca2+-ATPase (SERCA) is unknown. Hence, in the present study, we aim to demonstrate if E2 favors AHR by increasing intracellular Ca2+ concentrations in guinea pig airway smooth muscle (ASM) through a mechanism involving Ca2+-ATPases. In guinea pig ASM, Ca2+ microfluorometry, muscle contraction, and Western blot were evaluated. Then, we performed molecular docking analysis between the estrogens and Ca2+ ATPases. In tracheal rings, E2 produced AHR to carbachol. In guinea pig myocytes, acute exposure to physiological levels of E2 modified the transient Ca2+ peak induced by caffeine to a Ca2+ plateau. The incubation with PMCA inhibitors (lanthanum and carboxyeosin, CE) partially reversed the E2-induced sustained plateau in the caffeine response. In contrast, cyclopiazonic acid (SERCA inhibitor), U-0126 (an inhibitor of ERK 1/2), and choline chloride did not modify the Ca2+ plateau produced by E2. The mitochondrial uniporter activity and the capacitative Ca2+ entry were unaffected by E2. In guinea pig ASM, Western blot analysis demonstrated PMCA1 and PMCA4 expression. The results from the docking modeling demonstrate that E2 binds to both plasma membrane ATPases. In guinea pig tracheal smooth muscle, inhibiting the PMCA with CE, induced hyperresponsiveness to carbachol. 17β-estradiol produces hyperresponsiveness by inhibiting the PMCA in the ASM and could be one of the mechanisms responsible for the increase in asthmatic crisis in women.

Prenatal inflammation remodels lung immunity and function by programming ILC2 hyperactivation

Here, we examine how prenatal inflammation shapes tissue function and immunity in the lung by reprogramming tissue-resident immune cells from early development. Maternal, but not fetal, type I interferon-mediated inflammation provokes expansion and hyperactivation of group 2 innate lymphoid cells (ILC2s) seeding the developing lung. Hyperactivated ILC2s produce increased IL-5 and IL-13 and are associated with acute Th2 bias, decreased Tregs, and persistent lung eosinophilia into adulthood. ILC2 hyperactivation is recapitulated by adoptive transfer of fetal liver precursors following prenatal inflammation, indicative of developmental programming at the fetal progenitor level. Reprogrammed ILC2 hyperactivation and subsequent lung immune remodeling, including persistent eosinophilia, is concomitant with worsened histopathology and increased airway dysfunction equivalent to papain exposure, indicating increased asthma susceptibility in offspring. Our data elucidate a mechanism by which early-life inflammation results in increased asthma susceptibility in the presence of hyperactivated ILC2s that drive persistent changes to lung immunity during perinatal development.

Sex differences in airway disease: estrogen and airway surface liquid dynamics

Biological sex differences exist for many airway diseases in which females have either worse or better health outcomes. Inflammatory airway diseases such as cystic fibrosis (CF) and asthma display a clear male advantage in post-puberty while a female benefit is observed in asthma during the pre-puberty years. The influence of menstrual cycle stage and pregnancy on the frequency and severity of pulmonary exacerbations in CF and asthma point to a role for sex steroid hormones, particularly estrogen, in underpinning biological sex differences in these diseases. There are many ways by which estrogen may aggravate asthma and CF involving disturbances in airway surface liquid (ASL) dynamics, inappropriate hyper-immune and allergenic responses, as well as exacerbation of pathogen virulence. The deleterious effect of estrogen on pulmonary function in CF and asthma contrasts with the female advantage observed in airway diseases characterised by pulmonary edema such as pneumonia, acute respiratory distress syndrome (ARDS) and COVID-19. Airway surface liquid hypersecretion and alveolar flooding are hallmarks of ARDS and COVID-19, and contribute to the morbidity and mortality of severe forms of these diseases. ASL dynamics encompasses the intrinsic features of the thin lining of fluid covering the airway epithelium which regulate mucociliary clearance (ciliary beat, ASL height, volume, pH, viscosity, mucins, and channel activating proteases) in addition to innate defence mechanisms (pathogen virulence, cytokines, defensins, specialised pro-resolution lipid mediators, and metabolism). Estrogen regulation of ASL dynamics contributing to biological sex differences in CF, asthma and COVID-19 is a major focus of this review.

Progesterone amplifies allergic inflammation and airway pathology in association with higher lung ILC2 responses

Perimenstrual worsening of asthma occurs in up to 40% of women with asthma, leading to increased acute exacerbations requiring clinical care. The role of sex hormones during these times remains unclear. In the current study, we used a translational approach to determine whether progesterone exacerbates allergic inflammation in the traditional chicken egg ovalbumin (OVA) model in BALB/c mice. Simultaneously, we used peripheral blood mononuclear cells (PBMC) from healthy human donors to assess the effects of progesterone on circulating group 2 innate lymphoid cells (ILC2). Briefly, lungs of ovariectomized (OVX) or sham-operated female (F-Sham) controls were implanted with a progesterone (P4, 25 mg) (OVX-P4) or placebo pellet (OVX-Placebo), followed by sensitization and challenge with ovalbumin (OVA). Progesterone increased total inflammatory histologic scores, increased hyper-responsiveness to methacholine (MCh), increased select chemokines in the bronchoalveolar lavage (BAL) and serum, and increased ILC2 and neutrophil numbers, along the airways compared with F-Sham-OVA and OVX-Placebo-OVA animals. Lung ILC2 were sorted from F-Sham-OVA, OVX-Placebo-OVA and OVX-P4-OVA treated animals and stimulated with IL-33. OVX-P4-OVA lung ILC2 were more responsive to interleukin 33 (IL-33) compared with F-Sham-OVA treated, producing more IL-13 and chemokines following IL-33 stimulation. We confirmed the expression of the progesterone receptor (PR) on human ILC2, and showed that P4 + IL-33 stimulation also increased IL-13 and chemokine production from human ILC2. We establish that murine ILC2 are capable of responding to P4 and thereby contribute to allergic inflammation in the lung. We confirmed that human ILC2 are also hyper-responsive to P4 and IL-33 and likely contribute to airway exacerbations following allergen exposures in asthmatic women with increased symptoms around the time of menstruation.NEW & NOTEWORTHY There is a strong association between female biological sex and severe asthma. We investigated the allergic immune response, lung pathology, and airway mechanics in the well-described chicken egg ovalbumin (OVA) model with steady levels of progesterone delivered throughout the treatment period. We found that progesterone enhances the activation of mouse group 2 innate lymphoid cells (ILC2). Human ILC2 are also hyper-responsive to progesterone and interleukin 33 (IL-33), and likely contribute to airway exacerbations following allergen exposures in women with asthma.

Neuroinflammation is dependent on sex and ovarian hormone presence following acute woodsmoke exposure

Woodsmoke (WS) exposure is associated with significant health-related sequelae. Different populations can potentially exhibit varying susceptibility, based on endocrine phenotypes, to WS and investigating neurological impacts following inhaled WS is a growing area of research. In this study, a whole-body inhalation chamber was used to expose both male and female C57BL/6 mice (n = 8 per group) to either control filtered air (FA) or acute WS (0.861 ± 0.210 mg/m3) for 4 h/d for 2 days. Neuroinflammatory and lipid-based biological markers were then assessed. In a second set of studies, female mice were divided into two groups: one group was ovariectomized (OVX) to simulate an ovarian hormone-deficient state (surgical menopause), and the other underwent Sham surgery as controls, to mechanistically assess the impact of ovarian hormone presence on neuroinflammation following FA and acute WS exposure to simulate an acute wildfire episode. There was a statistically significant impact of sex (P ≤ 0.05) and statistically significant interactions between sex and treatment in IL-1β, CXCL-1, TGF-β, and IL-6 brain relative gene expression. Hippocampal and cortex genes also exhibited significant changes in acute WS-exposed Sham and OVX mice, particularly in TGF-β (hippocampus) and CCL-2 and CXCL-1 (cortex). Cortex GFAP optical density (OD) showed a notable elevation in male mice exposed to acute WS, compared to the control FA. Sham and OVX females demonstrated differential GFAP expression, depending on brain region. Overall, targeted lipidomics in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) serum and brain lipids demonstrated more significant changes between control FA and acute WS exposure in female mice, compared to males. In summary, male and female mice show distinct neuroinflammatory markers in response to acute WS exposure. Furthermore, ovarian hormone deficiency may impact the neuroinflammatory response following an acute WS event.

LINC00158 modulates the function of BEAS-2B cells via targeting BCL11B and ameliorates OVA-LPS-induced severe asthma in mice models

Persistent type (T) 2 airway inflammation plays an important role in the development of severe asthma. However, the molecular mechanisms leading to T2 severe asthma have yet to be fully clarified. Human normal lung epithelial cells (BEAS-2B cells) were transfected with LINC00158/BCL11B plasmid/small interfering RNA (siRNA). Levels of epithelial-mesenchymal transition (EMT)-related markers were measured using real-time qPCR (RT-qPCR) and western blot. A dual luciferase reporter assay was used to validate the targeting relationship between LINC00158 and BCL11B. The effects of LINC00158-lentivirus vector-mediated overexpression and dexamethasone on ovalbumin (OVA)/lipopolysaccharide (LPS)-induced severe asthma were investigated in mice in vivo. Our study showed that overexpression of LINC00158/BCL11B inhibited the levels of EMT-related proteins, apoptosis, and promoted the proliferation of BEAS-2B cells. BCL11B was a direct target of LINC00158. And LINC00158 targeted BCL11B to regulate EMT, apoptosis, and cell proliferation of BEAS-2B cells. Compared with severe asthma mice, LINC00158 overexpression alleviated OVA/LPS-induced airway hyperresponsiveness and airway inflammation, including reductions in T helper 2 cells factors in lung tissue and BALF, serum total- and OVA-specific IgE, inflammatory cell infiltration, and goblet cells hyperplasia. In addition, LINC00158 overexpression alleviated airway remodeling, including reduced plasma TGF-β1 and collagen fiber deposition, as well as suppression of EMT. Additionally, overexpression of LINC00158 enhanced the therapeutic effect of dexamethasone in severe asthmatic mice models. LINC00158 regulates BEAS-2B cell biological function by targeting BCL11B. LINC00158 ameliorates T2 severe asthma in vivo and provides new insights into the clinical treatment of severe asthma.

The role of hormones in ILC2-driven allergic airway inflammation

Group 2 innate lymphoid cells (ILC2s) are a type of innate immune cells that produce a large amount of IL-5 and IL-13 and two cytokines that are crucial for various processes such as allergic airway inflammation, tissue repair and tissue homeostasis. It is known that damaged epithelial-derived alarmins, such as IL-33, IL-25 and thymic stromal lymphopoietin (TSLP), are the predominant ILC2 activators that mediate the production of type 2 cytokines. In recent years, abundant studies have found that many factors can regulate ILC2 development and function. Hormones synthesized by the body's endocrine glands or cells play an important role in immune response. Notably, ILC2s express hormone receptors and their proliferation and function can be modulated by multiple hormones during allergic airway inflammation. Here, we summarize the effects of multiple hormones on ILC2-driven allergic airway inflammation and discuss the underlying mechanisms and potential therapeutic significance.

Role of G-protein-coupled estrogen receptor in the pathogenesis of chronic asthma

BACKGROUND AND AIM

G protein-coupled estrogen receptor (GPER) is an estrogen receptor located on the plasma membrane. We previously reported that the administration of G-1, a GPER-specific agonist, suppressed development of acute ovalbumin (OVA)-induced asthma in a mouse model. Herein, we evaluate the involvement of GPER in a mouse model of chronic OVA asthma.

METHODS

G-1 or saline was administered subcutaneously to BALB/c mice with chronic OVA asthma, and pathological and immunological evaluation was performed. In addition, Foxp3-expressing CD4-positive T-cells in the spleen and ILC2 in the lungs were measured using flow cytometry.

RESULTS

We observed a significant decrease in the number of inflammatory cells in the bronchoalveolar lavage fluid (BALF) in the G-1 treated group. In the airways, inflammatory cell accumulation, Th2 cytokines (IL-4, IL-5, IL-13, and eotaxin) and epithelial cytokine TSLP were suppressed, while in the BALF, anti-inflammatory cytokines (IL-10 and TGF-β) were increased. Furthermore, in splenic mononuclear cells, Foxp3-expressing CD4-positive T-cells were increased in the G-1 group, whereas treatment with G-1 did not change the percentage of ILC2 in the lungs.

CONCLUSION

G-1 administration suppressed allergic airway inflammation in mice with chronic OVA asthma. GPER may be a potential therapeutic target for chronic allergic asthma.

Prenatal inflammation reprograms hyperactive ILC2s that promote allergic lung inflammation and airway dysfunction

Allergic asthma is a chronic respiratory disease that initiates in early life, but causal mechanisms are poorly understood. Here we examined how prenatal inflammation shapes allergic asthma susceptibility by reprogramming lung immunity from early development. Induction of Type I interferon-mediated inflammation during development provoked expansion and hyperactivation of group 2 innate lymphoid cells (ILC2s) seeding the developing lung. Hyperactivated ILC2s produced increased IL-5 and IL-13, and were associated with acute Th2 bias, eosinophilia, and decreased Tregs in the lung. The hyperactive ILC2 phenotype was recapitulated by adoptive transfer of a fetal liver precursor following exposure to prenatal inflammation, indicative of developmental programming. Programming of ILC2 function and subsequent lung immune remodeling by prenatal inflammation led to airway dysfunction at baseline and in response to papain, indicating increased asthma susceptibility. Our data provide a link by which developmental programming of progenitors by early-life inflammation drives lung immune remodeling and asthma susceptibility through hyperactivation of lung-resident ILC2s.

One Sentence Summary

Prenatal inflammation programs asthma susceptibility by inducing the production of hyperactivated ILC2s in the developing lung.