IgE-mediated asthma: New revelations and future insights

Limosilactobacillus fermentum modulates the gut-airway axis by improving the immune response through FOXP3 activation on combined allergic rhinitis and asthma syndrome (CARAS)

Combined allergic rhinitis and asthma syndrome (CARAS) is an allergic airway inflammatory disorder orchestrated by the type 2 immune response. The close gut-lung relationship has been described, however, the effect of gut-modulating agents such as probiotics in allergic airway disorder is unclear. Thus, the goal of this study was to evaluate theLimosilactobacillus fermentumsupplementation in animals with CARAS. Therefore, BALB/c mice were ovalbumin (OVA) -sensitized and -challenged after being supplemented withL. fermentum. Animals, previously probiotic supplemented, showed a decrease (p < 0.05) of inflammatory cell migration, mainly eosinophil, into the nasal (NALF) and the bronchoalveolar (BALF) fluids as well as reduction of the allergic signs such as sneezing, nasal rubbings, and nasal hyperreactivity induced by histamine as compared with non-supplemented animals. In the systemic context,L. fermentumreduced eosinophilia and the serum levels of OVA-specific IgE. The altered histological aspects of nasal and lung tissues of animals with CARAS were effectively ameliorated byL. fermentum. In the BALF, the immunomodulatory effect was due to the decreasing of type 2 and 3 cytokines (IL-4, IL-13, IL-5 and IL-17A) dependent on type 1 (IFN-γ) and Treg (IL-10) cytokine increasing. Indeed,L. fermentumimproved the FOXP3 activation. Additionally, these effects correlate with the amplification of the gut response as increasing short-chain fatty acids (SCFAs) levels, gut epithelium barrier (ZO-1) maintenance, and colon tissue integrity. These data pointed out that animals' probiotic supplemented presented immunomodulatory responses in CARAS experimental model by activating the intracellular transduction signal underlying the IL-10 gene transcription.

PM2.5 exposure regulates Th1/Th2/Th17 cytokine production through NF-κB signaling in combined allergic rhinitis and asthma syndrome

BACKGROUND

Particulate matter (PM) is a major component of air pollution from emissions from anthropogenic and natural sources and is a serious problem worldwide due to its adverse effects on human health. Increased particulate air pollution increases respiratory disease-related mortality and morbidity. However, the impact of PM with an aerodynamic diameter of ≤ 2.5 μm (PM2.5) on combined allergic rhinitis and asthma syndrome (CARAS) remains to be elucidated. Accordingly, in the present study, we investigated the effect of PM2.5 in an ovalbumin (OVA)-induced CARAS mouse model with a focus on NF-κB signaling.

METHODOLOGY

We established an OVA-induced mouse model of CARAS to determine the effects of exposure to PM2.5. BALB/c mice were randomly divided into four groups: (1) naive, (2) PM2.5, (3) CARAS, and (4) CARAS/PM2.5. Mice were systemically sensitized with OVA and challenged with inhalation of ultrasonically nebulized 5% OVA three times by intranasal instillation of OVA in each nostril for 7 consecutive days. Mice in the PM2.5 and CARAS/PM2.5 groups were then exposed to PM2.5 by intranasal instillation of PM2.5 for several days. We then examined the impacts of PM2.5 exposure on histopathology and NF-κB signaling in our OVA-induced CARAS mouse model.

RESULTS

PM2.5 increased infiltration of eosinophils in bronchoalveolar lavage fluid (BALF) samples and inflammatory cells in lung tissue. It also increased production of GATA3, RORγ, IL-4, IL-5, IL-13, and IL-17 in nasal lavage fluid (NALF) and BALF samples in the CARAS mouse model, but secretion of IL-12 and IFN-γ was suppressed. Exposure to PM2.5 increased OVA-specific IgE and IgG₁ levels in serum, inflammatory cell infiltration in the airways, and fibrosis in lung tissue. It also activated the NF-κB signaling pathway, increasing Th2/Th17 cytokine levels while decreasing Th1 cytokine expression, thereby inducing an inflammatory response and promoting inflammatory cell infiltration in nasal and lung tissue.

CONCLUSION

Our results demonstrate that PM2.5 can aggravate OVA-induced CARAS.

Ginsenoside Rh1 attenuates ovalbumin-induced asthma by regulating Th1/Th2 cytokines balance

Ginsenoside Rh1 (Rh1) has anti-inflammatory effects in asthma mice, but the underlying mechanism remains unclear. BALB/c mice were sensitized and challenged with ovalbumin (OVA) to construct asthma model. Mice received Rh1 or tiotropium bromide 0.5 h before OVA challenge. Airway morphology and airway remodeling were assessed by HE staining and Masson's trichrome staining, respectively. Th1/Th2 cytokines in serum or broncho alveolar lavage fluid (BALF) were measured by ELISA kits. Rh1 significantly alleviated the lung resistance and airway resistance, and reduced the number of total inflammation cells, eosinophils, neutrophils, and lymphocytes in BALF of the asthmatic mice. The morphological changes and collagen deposition of airway were also reduced by Rh1 in asthmatic mice. The increase of Eotaxin, IL-4, IL-5, IL-13, and IL-33 and the decrease of IL-12 and IFN-γ in both BALF and serum of OVA exposed mice were reversed by Rh1. Rh1 attenuates OVA-induced asthma in the mice model by regulating Th1/Th2 cytokines balance.

Inhibition of phosphodiesterase suppresses allergic lung inflammation by regulating MCP-1 in an OVA-induced asthma murine model with co-exposure to lipopolysaccharide

Objective

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Conclusion

Exposure to formaldehyde at low temperatures aggravates allergic asthma involved in transient receptor potential ion channel

Studies have indicated that formaldehyde and low temperature are considered to be the factors associated with several respiratory diseases. However, the effect of co-exposure to formaldehyde and low temperature on allergic asthma, and the potential mechanisms, are unknown. In this study, an allergic asthma mouse model was built and mice were exposed to 0.8 mg/m³ formaldehyde and/or subjected to low temperatures of 16 °C. The data showed that exposure to either low temperature or formaldehyde did not induce a significant aggravation on allergic asthma. However, simultaneous exposure to formaldehyde and low temperature was shown to aggravate mucus hypersecretion and inflammation in the lung, lead to an exacerbation of allergic asthma. After blocking the TRPM8 and TRPA1 ion channels, the levels of inflammatory factors reduced. These results demonstrated that co-exposure to formaldehyde and low temperature exacerbate allergic asthma, and that TRPM8 and TRPA1 are involved in this process.

Warifteine and methylwarifteine inhibited the type 2 immune response on combined allergic rhinitis and asthma syndrome (CARAS) experimental model through NF-кB pathway

CARAS is an airway inflammation of allergic individuals, with a type 2 immune response. The pharmacotherapy is based on drugs with relevant side effects. Thus, the goal of this study evaluated the alkaloids warifteine (War) and methylwarifteine (Mwar) from Cissampelos sympodialis in CARAS experimental model. Therefore, BALB/c mice were ovalbumin (OVA) sensitized and challenged and treated with both alkaloids. Treated animals showed a decrease (p < 0.05) of allergic signs as sneezing and nasal rubbings, histamine nasal hyperreactivity, and inflammatory cell migration into the nasal (NALF) and the bronchoalveolar (BALF) fluids, main eosinophils. In the systemic context, only Mwar reduced eosinophilia, however, both alkaloids reduced the serum levels of OVA-specific IgE. Histological analysis revealed that the alkaloids decreased the inflammatory cells into the subepithelial and perivascular regions of nasal tissue and the peribronchiolar and perivascular regions of lung tissue. Hyperplasia/hypertrophy of nasal and lung goblet cells were reduced in alkaloid treated animals; however, the treatment did not change the number of mast cells. The lung hyperactivity was attenuated by reducing hyperplasia of fibroblast and collagen fiber deposition and hypertrophy of the lung smooth muscle layer. The immunomodulatory effect was by decreasing of type 2 and 3 cytokines (IL-4/IL-13/IL-5 and IL-17A) dependent by the increasing of type 1 cytokine (IFN-γ) into the BALF of treated sick animals. Indeed, both alkaloids reduced the NF-кB (p65) activation on granulocytes and lymphocytes, indicating that the alkaloids shut down the intracellular transduction signals underlie the transcription of T_H2 cytokine gens.

Exposure to both formaldehyde and high relative humidity exacerbates allergic asthma by activating the TRPV4-p38 MAPK pathway in Balb/c mice

Some studies have indicated that formaldehyde, a ubiquitous environmental pollutant, can induce or aggravate allergic asthma. Epidemiological studies have also shown that the relative humidity indoors may be an independent and a key factor associated with the aggravation of allergic asthma. However, the synergy of humidity and formaldehyde on allergic asthma and the mechanism underlying this effect remain largely unknown. In this study, we aim to determine the effect of high relative humidity and/or formaldehyde exposure on allergic asthma and explore the underlying mechanisms. Male Balb/c mice were modeled with ovalbumin (OVA) and exposure to 0.5 mg/m³ formaldehyde and/or different relative humidity (60%/75%/90%). Histopathological changes, pulmonary function, Th1/Th2 balance, the status of mucus hypersecretion and the levels of inflammatory factors were detected to assess the exacerbation of allergic asthma. The levels of the transient receptor potential vanilloid 4 (TRPV4), calcium ion and the activation of p38 mitogen-activated protein kinases (p38 MAPK) were detected to explore the underlying mechanisms. The results showed that exposure to high relative humidity or to 0.5 mg/m³ formaldehyde alone had a slight, but not significant, affect on allergic asthma. However, the pathological response and airway hyperresponsiveness (AHR) were greatly aggravated by simultaneous exposure to 0.5 mg/m³ formaldehyde and 90% relative humidity. Blocking TRPV4or p38 MAPK using HC-067047 and SB203580 respectively, effectively alleviated the exacerbation of allergic asthma induced by this simultaneous exposure to formaldehyde and high relative humidity. The results show that when formaldehyde and high relative humidity are present this can enhance the activation of the TRPV4 ion channel in the lung leading to the aggravation of the p38 MAPK activation, resulting in the exacerbation of inflammation and hypersecretion of mucus in the airways.

Immunoglobulin E as a Biomarker in Asthma

Asthma is a chronic disease that affects children and adults with significant morbidity and mortality. It is multifactorial, with genetic and environmental factors affecting the overall course of the disease. Both specific and total immunoglobulin (Ig)E can be used in specific phenotypes such as allergic asthma. Using IgE as a biomarker for asthma provides a target for management and treatment. Biotherapeutics continue to emerge as important advances in asthma treatment, and their effect on IgE and its biomarker role continue to be studied.

Type 2 immunity in asthma

Type 2-immunity represents the typical adaptive response to allergen exposure in atopic individuals. It mainly involves Th2 cells and immunoglobulin E, as the main orchestrators of type 2-inflammation. Recently, it has been highlighted that allergens may be responsible for a Th2 response beside specific IgE activation and that a number of other environmental stimuli, such as viruses and pollutants, can trigger the same pattern of inflammation beyond atopy. Emerging data sustain a substantial role of the so-called epithelial dysfunction in asthma pathogenesis, both from anatomic and functional point of view. Furthermore an increasing amount of evidence demonstrates the relevance of innate immunity in polarizing a Th2 impaired response in asthmatic patients. Under this perspective, the complex cross-talking between airway epithelium, innate and adaptive immunity is emerging as a major determinant of type 2-inflammation beyond allergens.

This review will include an update on the relevance of dysregulation of innate and adaptive type 2-immunity in asthma pathogenesis, particularly severe asthma, and on the role of the allergens that are associated with severe asthma. Type 2-immunity also will be reviewed in the light of the current and upcoming targeted treatments for severe asthma.

Sensing and responding to allergic response cytokines through a genetically encoded circuit

While constantly rising, the prevalence of allergies is globally one of the highest among chronic diseases. Current treatments of allergic diseases include the application of anti-histamines, immunotherapy, steroids, and anti-immunoglobulin E (IgE) antibodies. Here we report mammalian cells engineered with a synthetic signaling cascade able to monitor extracellular pathophysiological levels of interleukin 4 and interleukin 13, two main cytokines orchestrating allergic inflammation. Upon activation of transgenic cells by these cytokines, designed ankyrin repeat protein (DARPin) E2_79, a non-immunogenic protein binding human IgE, is secreted in a precisely controlled and reversible manner. Using human whole blood cell culturing, we demonstrate that the mammalian dual T helper 2 cytokine sensor produces sufficient levels of DARPin E2_79 to dampen histamine release in allergic subjects exposed to allergens. Hence, therapeutic gene networks monitoring disease-associated cytokines coupled with in situ production, secretion and systemic delivery of immunomodulatory biologics may foster advances in the treatment of allergies.

The standard treatment for an allergic response is anti-histamines, steroids and anti-IgE antibodies. Here the authors present a genetic circuit that senses IL-4 and IL-13 and responses with DARPin production to bind IgE.

Asthma Biomarkers: Do They Bring Precision Medicine Closer to the Clinic?

Measurement of biomarkers has been incorporated within clinical research of asthma to characterize the population and to associate the disease with environmental and therapeutic effects. Regrettably, at present, there are no specific biomarkers, none is validated or qualified, and endotype-driven choices overlap. Biomarkers have not yet reached clinical practice and are not included in current asthma guidelines. Last but not least, the choice of the outcome upholding the value of the biomarkers is extremely difficult, since it has to reflect the mechanistic intervention while being relevant to both the disease and the particular person. On the verge of a new age of asthma healthcare standard, we must embrace and adapt to the key drivers of change. Disease endotypes, biomarkers, and precision medicine represent an emerging model of patient care building on large-scale biologic databases, omics and diverse cellular assays, health information technology, and computational tools for analyzing sizable sets of data. A profound transformation of clinical and research pattern from population to individual risk and from investigator-imposed subjective disease clustering (hypothesis driven) to unbiased, data-driven models is facilitated by the endotype/biomarker-driven approach.

Clinical Toxicology and Its Relevance to Asthma and Atopy

Although both the prevalence of asthma and the prescription drug use, notably the opiate analgesic class, epidemics are increasing, there is a complex interplay between both disorders, with both protective and exacerbating factors involved in the effect of opiates on asthma pathogenesis and clinical severity. This review examines the airway effects, both immunologic and neurologic, of opiates, which may interact and result in protection or exacerbation of asthma.