Effects of S100A9 in a rat model of asthma and in isolated tracheal spirals

Research on the Mechanism and Application of Acupuncture Therapy for Asthma: A Review

Asthma is a high-risk disease based on airway hyperresponsiveness (AHR). In this review, we found that there are many studies on clinical therapy for asthma that focus on the efficacy of acupuncture therapy and its mechanisms, including the functional connectivity of different brain regions, with the aid of functional magnetic resonance imaging (fMRI), immune responses/cell recognition (innate lymphoid cells and balance of Th1/Th2 and Treg/Th17), intracellular mechanism (autophagy, endoplasmic reticulum stress, and epigenetic alteration), and ligand-receptor/chemical signaling pathway (neurotransmitter, hormone, and small molecules). In this review, we summarized the clinical and experimental evidence for the mechanisms of acupuncture therapy in asthma to offer insights into drug discovery and clinical therapy. Given the paucity of clinical studies on the mechanisms of acupuncture in the treatment of asthma, this review notably included studies based on animal models to investigate the mechanisms of acupuncture in the treatment of asthma.

Clinical features and nasal inflammation in asthma and allergic rhinitis

Asthma and allergic rhinitis (AR) are widely considered to be the most common chronic inflammatory disorders. This study was performed to investigate the clinical features, disease severity, and upper airway inflammation among patients with asthma, AR, and asthma comorbid AR. Blood and nasal lavage fluid samples were collected from patients with isolated asthma (n = 23), isolated AR (n = 22), and asthma comorbid AR (n = 22). Demographic data, symptom evaluation, and spirometry were obtained from all subjects. The levels of interleukin (IL)-4, IL-5, IL-13, IL-17, IL-25, IL-33, and S100 proteins were measured in the nasal lavage fluid. Compared with isolated asthma, patients with asthma comorbid AR showed a lower quality of life according to the asthma quality-of-life questionnaire (AQLQ) score (6.11 ± 0.47 vs. 6.45 ± 0.35, P = 0.007). Additionally, no significant difference in the levels of IL-4 (P = 0.116), IL-25 (P = 0.235), and S100A12 (P = 0.392) was observed in nasal lavage fluid among three groups. However, miniscule levels of IL-5, IL-17, IL-13, IL-33, S100A8, and S100A9 were detected in nasal lavage fluid in all three groups. Patients with asthma comorbid AR showed an increased level of systemic cytokine in plasma than that of patients with isolated AR or asthma alone. The finding from our study may help clinicians to better understand the airway inflammation among asthma patients with or without AR.

Inhibitory Effect of S100A11 on Airway Smooth Muscle Contraction and Airway Hyperresponsiveness

OBJECTIVE

S100A11 is a member of the S100 calcium-binding protein family and has intracellular and extracellular regulatory activities. We previously reported that S100A11 was differentially expressed in the respiratory tracts of asthmatic rats as compared with normal controls. Here, we aimed to analyze the potential of S100A11 to regulate both allergen-induced airway hyperresponsiveness (AHR) as well as acetylcholine (ACh)-induced hypercontractility of airway smooth muscle (ASM) and contraction of ASM cells (ASMCs).

METHODS

Purified recombinant rat S100A11 protein (rS100A11) was administered to OVA-sensitized and challenged rats and then the AHR of animals was measured. The relaxation effects of rS100A11 on ASM were detected using isolated tracheal rings and primary ASMCs. The expression levels of un-phosphorylated myosin light chain (MLC) and phosphorylated MLC in ASMCs were analyzed using Western blotting.

RESULTS

Treatment with rS100A11 attenuated AHR in the rats. ASM contraction assays showed that rS100A11 reduced the contractile responses of isolated tracheal rings and primary ASMCs treated with ACh. In addition, rS100A11 markedly decreased the ACh-induced phosphorylation of the myosin light chain in ASMCs. Moreover, rS100A11 also suppressed the contractile response of tracheal rings in calcium-free buffer medium.

CONCLUSION

These results indicate that S100A11 protein can relieve AHR by relaxing ASM independently of extracellular calcium. Our data support the idea that S100A11 is a potential therapeutic target for reducing airway resistance in asthma patients.

Cyclophilin A Plays Potential Roles in a Rat Model of Asthma and Suppression of Immune Response

Purpose

Cyclophilin A (CypA) inhibits CD4⁺ T cell signal transduction via interleukin-2-inducible T-cell kinase (Itk), a tyrosine kinase required for T helper (Th) 2 cells function. Furthermore, mice with CypA silencing developed allergic diseases associated with increased Th2 cytokines production. CD4⁺ T cells with a Th2-cytokine pattern have been demonstrated to have a pivotal role in the pathogenesis of asthma. However, the effects of CypA in regulating immunity in asthma and in relieving asthmatic symptoms in vivo are entirely unknown.

Methods

Recombinant CypA protein (rCypA) was generated and purified. Ovalbumin (OVA)-challenged asthmatic rats model and acetylcholine chloride (ACh)-induced contraction of tracheal spirals were established. The pulmonary resistance (RL) value of asthmatic rats in vivo and the isometric tension of tracheal spirals ex vivo were recorded by MFLab 3.01 software. The levels of Th1 and Th2 cytokines and the quantities of immunoglobulin (IgA, IgG, IgM and IgE) in the supernatants of rat spleen lymphocytes were detected and analysed by bio-plex Suspension Array System and ELISA, respectively. CD4⁺ T cells were separated by MicroBeads, and the levels of interleukin (IL)-4 and interferon-γ (IFN-γ) were detected by ELISA.

Results

rCypA (10 ng/kg) significantly reduced RL within 2–7 min in OVA-challenged asthmatic rats in vivo, and there were no significant differences compared with terbutaline (TB) and hydrocortisone (HC). Furthermore, rCypA (10 ng/mL) significantly reduced the isometric tension in the ACh-induced contraction of the tracheal spiral ex vivo, and the effect of rCypA was better than that of TB. Additionally, rCypA suppressed the secretion of both Th1 and Th2 cytokines, and the suppressive effects of rCypA were stronger than those of HC, especially on Th2 cytokines.

Conclusion

These findings indicate that CypA may serve as a potential novel therapeutic strategy for asthma.

The axis of the receptor for advanced glycation endproducts in asthma and allergic airway disease

Asthma is a generalized term that describes a scope of distinct pathologic phenotypes of variable severity, which share a common complication of reversible airflow obstruction. Asthma is estimated to affect almost 400 million people worldwide, and nearly ten percent of asthmatics have what is considered "severe" disease. The majority of moderate to severe asthmatics present with a "type 2-high" (T2-hi) phenotypic signature, which pathologically is driven by the type 2 cytokines Interleukin-(IL)-4, IL-5, and IL-13. However, "type 2-low" (T2-lo) phenotypic signatures are often associated with more severe, steroid-refractory neutrophilic asthma. A wide range of clinical and experimental studies have found that the receptor for advanced glycation endproducts (RAGE) plays a significant role in the pathogenesis of asthma and allergic airway disease (AAD). Current experimental data indicates that RAGE is a critical mediator of the type 2 inflammatory reactions which drive the development of T2-hi AAD. However, clinical studies demonstrate that increased RAGE ligands and signaling strongly correlate with asthma severity, especially in severe neutrophilic asthma. This review presents an overview of the current understandings of RAGE in asthma pathogenesis, its role as a biomarker of disease, and future implications for mechanistic studies, and potential therapeutic intervention strategies.

Calprotectin in Lung Diseases

Calprotectin (CLP) is a heterodimer formed by two S-100 calcium-binding cytosolic proteins, S100A8 and S100A9. It is a multifunctional protein expressed mainly by neutrophils and released extracellularly by activated or damaged cells mediating a broad range of physiological and pathological responses. It has been more than 20 years since the implication of S100A8/A9 in the inflammatory process was shown; however, the evaluation of its role in the pathogenesis of respiratory diseases or its usefulness as a biomarker for the appropriate diagnosis and prognosis of lung diseases have only gained attention in recent years. This review aimed to provide current knowledge regarding the potential role of CLP in the pathophysiology of lung diseases and describe how this knowledge is, up until now, translated into daily clinical practice. CLP is involved in numerous cellular processes in lung health and disease. In addition to its anti-microbial functions, CLP also serves as a molecule with pro- and anti-tumor properties related to cell survival and growth, angiogenesis, DNA damage response, and the remodeling of the extracellular matrix. The findings of this review potentially introduce CLP in daily clinical practice within the spectrum of respiratory diseases.

Serum Calprotectin Is a Potential Marker in Patients with Asthma

BACKGROUND

Calprotectin is the major cytosolic protein in neutrophil granulocytes. Although asthma is known to cause eosinophilic inflammation, some patients with asthma have non-eosinophilic inflammation, which is characterized by local neutrophilic inflammation. The aim of this study was to assess calprotectin expression levels in a mouse model of asthma, and to observe the relationship of serum calprotectin level and clinical variables in patients with asthma.

METHODS

Mice were sensitized and challenged with 10 μg and 20 μg of Aspergillus fumigatus, respectively; mice treated with saline were used as a control. The levels of calprotectin were determined using enzyme-linked immunosorbent assay, immunoblotting, and immunohistochemical analysis. The serum levels of calprotectin were also assessed in patients with asthma. The relationship between calprotectin and clinicopathological characteristics was determined.

RESULTS

Calprotectin, S100A8, and S100A9 expression was elevated in the mouse lungs, calprotectin levels were higher in the serum of patients with asthma (n = 33) compared with those of healthy individuals (n = 28). Calprotectin levels correlated with forced expiratory volume in one second/forced vital capacity (r = -0.215, P = 0.043), smoke amount (r = 0.413, P = 0.017), body mass index (r = -0.445, P = 0.000), and blood neutrophil percentage (r = 0.300, P = 0.004) in patients with asthma.

CONCLUSION

Our data suggest that calprotectin could potentially be used as a biomarker for asthma.

Cathelicidin and Calprotectin Are Disparately Altered in Murine Models of Inflammatory Arthritis and Airway Inflammation

Cationic host defense peptides (CHDP) are immunomodulatory molecules that control infections and contribute to immune homeostasis. CHDP such as cathelicidin and calprotectin expression is altered in the arthritic synovium, and in the lungs of asthma and COPD patients. Recent studies suggest a link between airway inflammation and the immunopathology of arthritis. Therefore, in this study we compared the abundance of mouse cathelicidin (CRAMP), defensins, and calprotectin subunits (S100A8 and S100A9) in murine models of collagen-induced arthritis (CIA) and allergen house dust mite (HDM)-challenged airway inflammation. CRAMP, S100A8, and S100A9 abundance were significantly elevated in the joint tissues of CIA mice, whereas these were decreased in the lung tissues of HDM-challenged mice, compared to naïve. We further compared the effects of administration of two different synthetic immunomodulatory peptides, IG-19 and IDR-1002, on cathelicidin and calprotectin abundance in the two models. Administration of IG-19, which controls disease progression and inflammation in CIA mice, significantly decreased CRAMP, S100A8, and S100A9 levels to baseline in the joints of the CIA mice, which correlated with the decrease in cellular influx in the joints. However, administration of IDR-1002, which suppresses HDM-induced airway inflammation, did not prevent the decrease in the levels of cathelicidin and calprotectin in the lungs of HDM-challenged mice. Cathelicidin and calprotectin levels did not correlate with leukocyte accumulation in the lungs of the HDM-challenged mice. Results of this study suggest that endogenous cathelicidin and calprotectin abundance are disparately altered, and may be differentially regulated, within local tissues in airway inflammation compared to arthritis.

S100A4 is secreted by airway smooth muscle tissues and activates inflammatory signaling pathways via receptors for advanced glycation end products

S100A4 is a low-molecular-mass (12 kDa) EF-hand Ca²⁺-binding S100 protein that is expressed in a broad range of normal tissue and cell types. S100A4 can be secreted from some cells to act in an autocrine or paracrine fashion on target cells and tissues. S100A4 has been reported in the extracellular fluids of subjects with several inflammatory diseases, including asthma. Airway smooth muscle plays a critical role in airway inflammation by synthesizing and secreting inflammatory cytokines. We hypothesized that S100A4 may play an immunomodulatory role in airway smooth muscle. Trachealis smooth muscle tissues were stimulated with recombinant His-S100A4, and the effects on inflammatory responses were evaluated. S100A4 induced the activation of Akt and NF-κB and stimulated eotaxin secretion. It also increased the expression of RAGE and endogenous S100A4 in airway tissues. Stimulation of airway smooth muscle tissues with IL-13 or TNF-α induced the secretion of S100A4 from the tissues and promoted the expression of endogenous receptors for advanced glycation end products (RAGE) and S100A4. The role of RAGE in mediating the responses to S100A4A was evaluated by expressing a mutant nonfunctional RAGE (RAGEΔcyto) in tracheal muscle tissues and by treating tissues with a RAGE inhibitor. S100A4 did not activate NF-κB or Akt in tissues that were expressing RAGEΔcyto or treated with a RAGE inhibitor, indicating that S100A4 mediates its effects by acting on RAGE. Our results demonstrate that inflammatory mediators stimulate the synthesis and secretion of S100A4 in airway smooth muscle tissues and that extracellular S100A4 acts via RAGE to mediate airway smooth muscle inflammation.

The Innate Immune Protein S100A9 Protects from T-Helper Cell Type 2-mediated Allergic Airway Inflammation

Calprotectin is a heterodimer of the proteins S100A8 and S100A9, and it is an abundant innate immune protein associated with inflammation. In humans, calprotectin transcription and protein abundance are associated with asthma and disease severity. However, mechanistic studies in experimental asthma models have been inconclusive, identifying both protective and pathogenic effects of calprotectin. To clarify the role of calprotectin in asthma, calprotectin-deficient S100A9^-/- and wild-type (WT) C57BL/6 mice were compared in a murine model of allergic airway inflammation. Mice were intranasally challenged with extracts of the clinically relevant allergen, Alternaria alternata (Alt Ext), or PBS every third day over 9 days. On Day 10, BAL fluid and lung tissue homogenates were harvested and allergic airway inflammation was assessed. Alt Ext challenge induced release of S100A8/S100A9 to the alveolar space and increased protein expression in the alveolar epithelium of WT mice. Compared with WT mice, S100A9^-/- mice displayed significantly enhanced allergic airway inflammation, including production of IL-13, CCL11, CCL24, serum IgE, eosinophil recruitment, and airway resistance and elastance. In response to Alt Ext, S100A9^-/- mice accumulated significantly more IL-13⁺IL-5⁺CD4⁺ T-helper type 2 cells. S100A9^-/- mice also accumulated a significantly lower proportion of CD4⁺ T regulatory (Treg) cells in the lung that had significantly lower expression of CD25. Calprotectin enhanced WT Treg cell suppressive activity in vitro. Therefore, this study identifies a role for the innate immune protein, S100A9, in protection from CD4⁺ T-helper type 2 cell hyperinflammation in response to Alt Ext. This protection is mediated, at least in part, by CD4⁺ Treg cell function.

Transgelin-2 as a therapeutic target for asthmatic pulmonary resistance

There is a clinical need for new bronchodilator drugs in asthma, because more than half of asthmatic patients do not receive adequate control with current available treatments. We report that inhibition of metallothionein-2 protein expression in lung tissues causes the increase of pulmonary resistance. Conversely, metallothionein-2 protein is more effective than β₂-agonists in reducing pulmonary resistance in rodent asthma models, alleviating tension in tracheal spirals, and relaxing airway smooth muscle cells (ASMCs). Metallothionein-2 relaxes ASMCs via transgelin-2 (TG2) and induces dephosphorylation of myosin phosphatase target subunit 1 (MYPT1). We identify TSG12 as a nontoxic, specific TG2-agonist that relaxes ASMCs and reduces asthmatic pulmonary resistance. In vivo, TSG12 reduces pulmonary resistance in both ovalbumin- and house dust mite-induced asthma in mice. TSG12 induces RhoA phosphorylation, thereby inactivating the RhoA-ROCK-MYPT1-MLC pathway and causing ASMCs relaxation. TSG12 is more effective than β₂-agonists in relaxing human ASMCs and pulmonary resistance with potential clinical advantages. These results suggest that TSG12 could be a promising therapeutic approach for treating asthma.

Involvements of p38 MAPK and oxidative stress in the ozone-induced enhancement of AHR and pulmonary inflammation in an allergic asthma model

Background

Exposure to ambient ozone (O₃) increases the susceptivity to allergens and triggers exacerbations in patients with asthma. However, the detailed mechanisms of action for O₃ to trigger asthma exacerbations are still unclear.

Methods

An ovalbumin (OVA)-established asthmatic mouse model was selected to expose to filtered air (OVA-model) or 1.0 ppm O₃ (OVA-O₃ model) during the process of OVA challenge. Next, the possible involvements of p38 MAPK and oxidative stress in the ozone actions on the asthma exacerbations were investigated on the mice of OVA-O₃ model by treating them with SB239063 (a p38 MAPK inhibitor), and/or the α-tocopherol (antioxidant). Biological measurements were conducted including airway hyperresponsiveness (AHR), airway resistance (Raw), lung compliance (CL), inflammation in the airway lumen and lung parenchyma, the phosphorylation of p38 MAPK and heat shock protein (HSP) 27 in the tracheal tissues, and the malondialdehyde (MDA) content and the glutathione peroxidase (GSH-Px) activity in lung tissues.

Results

In OVA-allergic mice, O3 exposure deteriorated airway hyperresponsiveness (AHR), airway resistance (Raw), lung compliance (CL) and pulmonary inflammation, accompanied by the increased oxidative stress in lung tissues and promoted p38 MAPK and HSP27 phosphorylation in tracheal tissues. Administration of SB239063 (a p38 MAPK inhibitor) on OVA-O3 model exclusively mitigated the Raw, the CL, and the BAL IL-13 content, while α-tocopherol (antioxidant) differentially reduced the BAL number of eosinophils and macrophages, the content of BAL hyaluronan, the peribronchial inflammation, as well as the mRNA expression of TNF-α and IL-5 in the lung tissues of OVA-O3 model. Administration of these two chemical inhibitors similarly inhibited the AHR, the BAL IFN-γ and IL-6 production, the perivascular lung inflammation and the lung IL-17 mRNA expression of OVA-O3 model. Interestingly, the combined treatment of both compounds together synergistically inhibited neutrophil counts in the BALF and CXCL-1 gene expression in the lung.

Conclusions

O₃ exposure during the OVA challenge process promoted exacerbation in asthma. Both p38 MAPK and oxidative stress were found to play a critical role in this process and simultaneous inhibition of these two pathways significantly reduced the O₃-elicited detrimental effects on the asthma exacerbation.

Decreased S100A9 Expression Promoted Rat Airway Smooth Muscle Cell Proliferation by Stimulating ROS Generation and Inhibiting p38 MAPK

Background. Asthma is a disease with a core abnormality in airway smooth muscle function, and the proliferation of airway smooth muscle cells (ASMCs) plays a pivotal role in asthma airway remodeling. Our previous study showed that S100A9 (S100 calcium-binding protein A9; 400 and 800 ng/mL) significantly inhibited rat ASMCs proliferation at 48 h, and 50–800 ng/mL S100A9 (50, 100, 200, 400, and 800 ng/mL) also induced a lasting effect by significantly inhibiting rat ASMCs proliferation at 72 h in a dose-dependent manner. However, the intracellular effects of S100A9 on ASMCs proliferation remain unknown. Methods. Rat ASMCs with stable S100A9 knockdown were generated using short hairpin RNA. The effects of decreased S100A9 expression on cellular proliferation, the production of reactive oxygen species (ROS), and p38 MAPK pathway protein expression were examined. Results. Decreased intracellular S100A9 expression significantly promoted platelet-derived growth factor-induced rat ASMCs proliferation and increased ROS production. The antioxidative agent N-acetylcysteine significantly inhibited rat ASMCs proliferation. Western blot results showed that the decreased intracellular S100A9 expression significantly inhibited p38 MAPK phosphorylation. Conclusion. Decreased S100A9 expression promoted rat ASMCs proliferation by stimulating ROS generation and inhibiting p38 MAPK. Our study may provide novel insights into the regulation of asthma airway remodeling.

Exogenous S100A8 protein inhibits PDGF-induced migration of airway smooth muscle cells in a RAGE-dependent manner

S100A8 is an important member of the S100 protein family, which is involved in intracellular and extracellular regulatory activities. We previously reported that the S100A8 protein was differentially expressed in the asthmatic respiratory tracts. To understand the potential role of S100A8 in asthma, we investigated the effect of recombinant S100A8 protein on the platelet-derived growth factor (PDGF)-induced migration of airway smooth muscle cells (ASMCs) and the underlying molecular mechanism by using multiple methods, such as impedance-based xCELLigence migration assay, transwell migration assays and wound-healing assays. We found that exogenous S100A8 protein significantly inhibited PDGF-induced ASMC migration. Furthermore, the migration inhibition effect of S100A8 was blocked by neutralizing antibody against the receptor for advanced glycation end-products (RAGE), a potential receptor for the S100A8 protein. These findings provide direct evidence that exogenous S100A8 protein inhibits the PDGF-induced migration of ASMCs through the membrane receptor RAGE. Our study highlights a novel role of S100A8 as a potential means of counteracting airway remodeling in chronic airway diseases.

Dexamethasone sodium phosphate intercalated layered double hydroxides and their therapeutic efficacy in a murine asthma model

Schematic diagram showing the intercalation of Dexa into the MgAl–LDH interlayers.

Simultaneous application of BrdU and WST-1 measurements for detection of the proliferation and viability of airway smooth muscle cells

Background

BrdU is a commonly used reagent in cell proliferation assays, and WST-1 measurement is widely used to detect cell viability. However, no previous study has formally reported the combination of the two assays, which may be used to detect the proliferation and viability simultaneously. In this study, we examined the effect of adding BrdU 2 h prior to the WST-1 assay and tried to test the possibility of the combined detection using rat airway smooth muscle cells.

Results

The WST-1 measurements obtained from the combined detection were consistent with those obtained from the separate detection, which suggested that the addition of BrdU 2 h prior to the WST-1 analysis did not affect the WST-1 results. The BrdU measurements obtained from the combined detection also demonstrated the same trend as that obtained from the separate detection, and dosages of 200, 400 and 800 ng/ml testing reagent significantly inhibited the proliferation of rat airway smooth muscle cells.

Conclusions

Our study suggests that the BrdU and WST-1 measurements can be applied simultaneously without mutual interference, which may increase the efficacy and consistency of these measurements to a certain extent.

The research of acupuncture effective biomolecules: retrospect and prospect

Acupuncture is an effective, safe and convenient therapy that has been applied for 2,500 years. The acupuncture researches have obtained significant improvement with the technical support of the life sciences and the studies of acupuncture have in turn accelerated the development of biomedical science. The effects of acupuncture influence important physiopathologic and biological activities, including gene expression, protein-protein interactions, and other biological processes. Cerebrospinal fluid, serum, organs, and tissues are reported to be carriers of the biomolecules of the effects of acupuncture. The paper summarized the progress of acupuncture effective biomolecules researches and found that biomolecules play important roles in the mechanism of acupuncture. With the development of omics technologies and translational medicine, the acupuncture research will meet both opportunities and challenges.

Functions of S100 proteins

The S100 protein family consists of 24 members functionally distributed into three main subgroups: those that only exert intracellular regulatory effects, those with intracellular and extracellular functions and those which mainly exert extracellular regulatory effects. S100 proteins are only expressed in vertebrates and show cell-specific expression patterns. In some instances, a particular S100 protein can be induced in pathological circumstances in a cell type that does not express it in normal physiological conditions. Within cells, S100 proteins are involved in aspects of regulation of proliferation, differentiation, apoptosis, Ca2+ homeostasis, energy metabolism, inflammation and migration/invasion through interactions with a variety of target proteins including enzymes, cytoskeletal subunits, receptors, transcription factors and nucleic acids. Some S100 proteins are secreted or released and regulate cell functions in an autocrine and paracrine manner via activation of surface receptors (e.g. the receptor for advanced glycation end-products and toll-like receptor 4), G-protein-coupled receptors, scavenger receptors, or heparan sulfate proteoglycans and N-glycans. Extracellular S100A4 and S100B also interact with epidermal growth factor and basic fibroblast growth factor, respectively, thereby enhancing the activity of the corresponding receptors. Thus, extracellular S100 proteins exert regulatory activities on monocytes/macrophages/microglia, neutrophils, lymphocytes, mast cells, articular chondrocytes, endothelial and vascular smooth muscle cells, neurons, astrocytes, Schwann cells, epithelial cells, myoblasts and cardiomyocytes, thereby participating in innate and adaptive immune responses, cell migration and chemotaxis, tissue development and repair, and leukocyte and tumor cell invasion.

An In Vivo and In Vitro Evaluation of the Mutual Interactions between the Lung and the Large Intestine

One of the most important theories of the traditional Chinese medicine is the exterior-interior relationship between the lung and the large intestine; so far, little direct experimental evidence has been reported to support such relationship. Here we for the first time investigated the mutual interactions between the lung and the large intestine by examining the relevancies between the pulmonary functions and the rectal resting pressure in the rat models of asthma and constipation. We also evaluated the effects of the lung homogenate and the large intestine homogenate on the isolated large intestine muscle strip and the isolated tracheal spiral, respectively. Our results showed that the pulmonary resistance and pulmonary compliance were closely related to the rectal resting pressure in the asthmatic rat model, while the rectal resting pressure was much correlated with the pulmonary resistance in the rat model of constipation. Moreover, it was shown that the lung homogenate could specifically contract the isolated large intestine muscle strip. Overall, this study provided new lines of evidence for the theory and highlighted the potential application in the treatment of the corresponding diseases.

Long term and standard incubations of WST-1 reagent reflect the same inhibitory trend of cell viability in rat airway smooth muscle cells

The WST-1 assay is an efficient test for cell viability measurement and the standard incubation time is 2h. In order to test if one-time addition of WST-1 reagent can reflect the relative cell viability trend of the testing agents at different time points, the effects of 2h standard incubation time and long term incubation time (2h+24h, 2h+48h) of WST-1 were compared in the rat airway smooth muscle cells (ASM cells) after adding of the testing protein MRP-14. Our study demonstrated that the effect of different dosages of the protein after 2h WST-1 incubation on ASM cells showed a tendency of inhibition and achieved the maximal inhibition effect at 72h. The relative cell viability trend of the 2h+24h group was the same to that of the 2h WST-1 incubation, which means that 24h prolonged incubation time of WST-1 reagent could still reflect the relative cell viability trend. In conclusion, the study suggested that the WST-1 is a proper candidate reagent for continuous monitation of cell viability.

Novel non-canonical TGF-β signaling networks: emerging roles in airway smooth muscle phenotype and function

The airway smooth muscle (ASM) plays an important role in the pathophysiology of asthma and chronic obstructive pulmonary disease (COPD). ASM cells express a wide range of receptors involved in contraction, growth, matrix protein production and the secretion of cytokines and chemokines. Transforming growth factor beta (TGF-β) is one of the major players in determining the structural and functional abnormalities of the ASM in asthma and COPD. It is increasingly evident that TGF-β functions as a master switch, controlling a network of intracellular and autocrine signaling loops that effect ASM phenotype and function. In this review, the various elements that participate in non-canonical TGF-β signaling, including MAPK, PI3K, WNT/β-catenin, and Ca(2+), are discussed, focusing on their effect on ASM phenotype and function. In addition, new aspects of ASM biology and their possible association with non-canonical TGF-β signaling will be discussed.

Enhanced bioavailability and efficiency of curcumin for the treatment of asthma by its formulation in solid lipid nanoparticles

Curcumin has shown considerable pharmacological activity, including anti-inflammatory, but its poor bioavailability and rapid metabolization have limited its application. The purpose of the present study was to formulate curcumin-solid lipid nanoparticles (curcumin-SLNs) to improve its therapeutic efficacy in an ovalbumin (OVA)-induced allergic rat model of asthma. A solvent injection method was used to prepare the curcumin-SLNs. Physiochemical properties of curcumin-SLNs were characterized, and release experiments were performed in vitro. The pharmacokinetics in tissue distribution was studied in mice, and the therapeutic effect of the formulation was evaluated in the model. The prepared formulation showed an average size of 190 nm with a zeta potential value of -20.7 mV and 75% drug entrapment efficiency. X-ray diffraction analysis revealed the amorphous nature of the encapsulated curcumin. The release profile of curcumin-SLNs was an initial burst followed by sustained release. The curcumin concentrations in plasma suspension were significantly higher than those obtained with curcumin alone. Following administration of the curcumin-SLNs, all the tissue concentrations of curcumin increased, especially in lung and liver. In the animal model of asthma, curcumin-SLNs effectively suppressed airway hyperresponsiveness and inflammatory cell infiltration and also significantly inhibited the expression of T-helper-2-type cytokines, such as interleukin-4 and interleukin-13, in bronchoalveolar lavage fluid compared to the asthma group and curcumin-treated group. These observations implied that curcumin-SLNs could be a promising candidate for asthma therapy.

S100A12 and the Airway Smooth Muscle: Beyond Inflammation and Constriction

Airway inflammation, lung remodeling, and Airway Hyperresponsiveness (AHR) are major features of asthma and Chronic Obstructive Pulmonary Disease (COPD). The inflammatory response to allergens, air pollutants, and other insults is likely to play a key role in promoting structural changes in the lung including the overabundance of Airway Smooth Muscle (ASM) seen in asthmatics. These alterations or remodeling could, in turn, impact the immunmodulatory actions of the ASM, the ASM's contractile properties, and the development of AHR. New evidences suggest that airway inflammation and AHR are not tightly related to each other and that the structural component of the airway, mainly the ASM, is a chief driver of AHR. Members of the S100/calgranulins family have been implicated in the regulation of inflammation and cell apoptosis in various systems. S100A12 is highly expressed in neutrophils and is one of the most abundant proteins in the lungs of patients with asthma or COPD. Studies with genetic engineered mice with smooth muscle cell-targeted expression of human S100A12 revealed that S100A12 reduces airway smooth muscle amounts and dampens airway inflammation and airway hyperreactivity in a model of allergic lung inflammation. Thus, targeting airway smooth muscle for instance through delivery of pro-apoptotic S100A12 could represent an attractive means to promote ASM apoptosis and to reduce ASM abundance in asthmatics.