Bradykinin B2 receptor expression in the bronchial mucosa of allergic asthmatics: the role of NF-kB

Clinically relevant effects of Mindfulness-Based Stress Reduction in individuals with asthma

Background

Psychological distress and comorbid psychopathology contribute to exacerbation risk in patients with asthma. Thus, interventions designed to reduce stress and improve emotion regulation, such as Mindfulness-Based Stress Reduction (MBSR), may augment standard care. Few studies have addressed this question and a paucity of data exists to determine the ability of MBSR to impact clinical outcomes in asthma.

Methods

This randomized controlled trial investigated effects of MBSR training on asthma control and airway inflammation, in relation to psychological symptoms, in adults with asthma. Participants were randomized to an 8-week MBSR training (n = 35) or wait-list control group (n = 34). Clinically relevant asthma assessments, including Asthma Control Questionnaire and inflammatory biomarkers, were collected at baseline and six approximately-monthly follow-ups. Self-reported mindfulness, distress, depression, and anxiety symptoms were assessed at baseline, post-intervention, and study completion. Chronic stress level was determined at baseline only.

Results

Asthma control improved significantly in individuals randomized to MBSR, relative to wait-list controls (p = .01; effect size d = 0.76), which was maintained at 4mo post-intervention. 32% of MBSR participants achieved a clinically significant improvement, based on the ACQ6 Minimally Important Difference, relative to 12% of wait-list participants. Moreover, MBSR-related improvement in asthma control was associated with a reduction in distress (p = .043) and the intervention was most efficacious for those with the highest baseline depressive symptoms (p = .023). Importantly, MBSR also reduced levels of exhaled nitric oxide, a biomarker of airway inflammation, relative to wait-list controls (p < .05).

Conclusion

Supporting and extending extant evidence of mind-body relationships in asthma and the benefits of stress reduction for these patients, this is, to the best of our knowledge, the first RCT to demonstrate that training in MBSR improves clinically relevant asthma outcomes. MBSR may thus be a valuable addition to optimal asthma management, particularly for those with comorbid psychopathology.

Clinical trial registration

NCT02157766.

Transcriptomic Analysis Exploring the Molecular Mechanisms of Hanchuan Zupa Granules in Alleviating Asthma in Rat

Objective

To investigate the molecular mechanisms of HCZP treatment of asthma.

Materials and Methods

Thirty Sprague Dawley (SD) rats were divided into normal, asthma, and HCZP groups (n = 10). The asthma model was sensitized by 1 mg ovalbumin (OVA)/aluminum hydroxide Al(OH)₃mixture and then challenged with 1% aerosolized OVA for four weeks. Rats in the HCZP group received 10.08 g/kg/d HCZP for four weeks during OVA challenge. Then, lung tissues of rats in each group were collected for RNA sequencing. Moreover, the expression level of some core genes was detected by using western blotting and immunohistochemistry.

Results

Inflammatory cell infiltration and pathological damage of the lungs improved in the HCZP group. Compared with the asthma group (0.049 ± 0.002 mm²/mm; 0.036 ± 0.006 mm²/mm; and 0.014 ± 0.001 mm²/mm), total wall thickness (0.042 ± 0.001 mm²/mm), inner wall thickness (0.013 ± 0.001 mm²/mm), and smooth muscle layer thickness (0.012 ± 0.001 mm²/mm) significantly decreased in the HCZP group. Bioinformatics analysis showed that hub genes such as bradykinin receptor B2 (Bdkrb2) and CD4 molecule (Cd4) had different expression patterns between model and HCZP groups. Two transcription factors, forkhead box Q1 (Foxq1) and nuclear factor of activated T cells 2 (Nfatc2), served important regulatory roles in asthma. Compared with the model group, Bdkrb2 protein expression increased and Nfatc2 protein expression decreased in the HCZP group. Discussion and Conclusion. HCZP could alleviate asthma via regulating the expression of several hub genes, which might serve as therapeutic targets for asthma. However, the mechanism of these genes will be studied in the future.

Fine particulate matter increases airway hyperresponsiveness through kallikrein-bradykinin pathway

Epidemiological studies have reported short-term fine particulate matter (PM2.5) exposure to increase incidence of asthma, related to the increase of airway hyperresponsiveness (AHR); however, the underlying mechanism remains unclear. Aim of this study was to elucidate the role of kallikrein in PM2.5-induced airway hyperresponsiveness and understand the underlying mechanism. Nose-only PM2.5 exposure system was used to generate a mouse model of airway hyperresponsiveness. Compared with the control group, PM2.5 exposure could significantly increase airway resistance, lung inflammation, kallikrein expression of bronchi-lung tissue and bradykinin (BK) secretion. However, these changes could be alleviated by kallikrein inhibitor. In addition，PM2.5 could increase the viability of human airway smooth muscle cells (hASMCs), accompanied by increased expression of kallikrein 14 (Klk14), bradykinin 2 receptor (B2R), bradykinin secretion and cytosol calcium level, while kallikrein 14 gene knockdown could significantly amelioratethe above response induced by PM2.5. Taken together, the data suggested kallikrein to play a key role in PM2.5-induced airway hyperresponsiveness, and that it could be a potential therapeutic target in asthma.

Systemic Administration of Calea pinnatifida Inhibits Inflammation Induced by Carrageenan in a Murine Model of Pulmonary Neutrophilia

Objective

The aim of this study was to investigate the anti-inflammatory effects of the crude extract (CE), derived fraction, and isolated compounds from Calea pinnatifida leaves in a mouse model of pulmonary neutrophilia.

Methods

The CE and derived fractions, hexane, ethyl acetate, and methanol, were obtained from C. pinnatifida leaves. The compounds 3,5- and 4,5-di-O-E-caffeoylquinic acids were isolated from the EtOAc fraction using chromatography and were identified using infrared spectroscopic data and nuclear magnetic resonance (¹H and ¹³C NMR). Leukocytes count, protein concentration of the exudate, myeloperoxidase (MPO) and adenosine deaminase (ADA), and nitrate/nitrite (NO _x ), tumor necrosis factor-alpha (TNF-α), interleukin-1-beta (IL-1β), and interleukin-17A (IL-17A) levels were determined in the pleural fluid leakage after 4 h of pleurisy induction. We also analyzed the effects of isolated compounds on the phosphorylation of both p65 and p38 in the lung tissue.

Results

The CE, its fractions, and isolated compounds inhibited leukocyte activation, protein concentration of the exudate, and MPO, ADA, NO _x , TNF-α, IL-1β, and IL-17A levels. 3,5- and 4,5-di-O-E-caffeoylquinic acids also inhibited phosphorylation of both p65 and p38 (P < 0.05).

Conclusion

This study demonstrated that C. pinnatifida presents important anti-inflammatory properties by inhibiting activated leukocytes and protein concentration of the exudate. These effects were related to the inhibition of proinflammatory mediators. The dicaffeoylquinic acids may be partially responsible for these anti-inflammatory properties through the inhibition of nuclear transcription factor kappa B and mitogen-activated protein kinase pathways.

Bradykinin contributes to immune liver injury via B2R receptor-mediated pathways in trichloroethylene sensitized mice: A role in Kupffer cell activation

We have previously shown trichloroethylene (TCE) induced occupational medicamentosa-like dermatitis due to TCE (OMLDT) with immune liver injury, and kallikrein-kinin system (KKS) activation as a probably mechanism underlying the immune damage. Bradykinin (BK) is an important active component of KKS system function, but the specific role of BK in the immune liver injury has never been examined. The present study aimed to explore the important role of BK and mechanisms of action in immune liver injury induced by TCE. TCE sensitization significantly increased the expression of BK receptor (B2R) in the liver. Compared to blank and vehicle control group, TCE sensitization positive mice developed exacerbated liver injury evidenced by elevated AST, ALT levels and hepatocyte damage. TCE sensitization also stimulated MAPK and STAT3 activation in liver tissue. B2R antagonist HOE140 ameliorated these changes. Kupffer cells (KCs) of the liver were also activated following TCE sensitization; both CD68⁺ KCs and CD16/CD32⁺ M1 type KCs were increased in TCE positive group. Further experiments isolated the KCs from the liver in each group and showed that TCE sensitization resulted activation of MAPK signal pathway which in turn caused release of the pro-inflammatory cytokines, IL-1β, IL-6, TNF-α, in KCs; the antagonist HOE140 again decreased these changes in KCs. These results uncover a novel role of BK and B2R cross-talk in KCs activation in TCE sensitized mice, mediated by pro-inflammatory cytokine release via MAPK and STAT3 activation, contributing to the immune liver injury.

Peptidoglycan induces bradykinin receptor 1 expression through Toll-like receptor 2 and NF-κB signaling pathway in human nasal mucosa-derived fibroblasts of chronic rhinosinusitis patients

Numerous studies have demonstrated that Gram-positive microbiomes play an important role in the pathogenesis and in the way of treatment of chronic rhinosinusitis (CRS). Kinins are inflammatory mediators and one of their receptors, namely bradykinin receptor 1 (BKR1 or B1R), is believed to be induced and involved in inflammation in pathophysiological conditions. In the present study, we investigated the effect of peptidoglycan (PGN), a major cell wall component of G(+) bacteria, on BKR expression and its signaling pathway in nasal fibroblasts from CRS without nasal polyp (CRSsNP). The PGN induced increases in B1R mRNA and protein production. The induction was abolished by the NF-κB and protein kinase A inhibitor. In parallel, the PGN treatment directly activated IκB/NF-κB signaling and CREB phosphorylation. Interestingly, a further analysis suggested no involvement of cAMP/PKA/CREB pathway in this induction. The B1R expression and IκB/NF-κB signaling pathway could be attenuated by Toll-like receptor-2 (TLR2) blocking/neutralizing Ab. In a functional assay, the addition of B1R selective agonist (Des-Arg¹⁰ -kallidin) to the fibroblasts after PGN stimulation led to an increase in CXCL8 release and p38 MAPK and ERK1/2 phosphorylation, which could be inhibited by the B1R antagonist. Taken together, our results revealed for the first time that PGN can increase B1R expression in human nasal mucosa-derived fibroblasts through TLR2 activation and NF-κB signaling pathway. This induction functionally leads to MAPKs activation and CXCL8 release upon B1R stimulation. Our results also suggest that a major component of G(+) bacteria can participate in B1R upregulation in nasal mucosa during CRSsNP progression.

Bradykinin in asthma: Modulation of airway inflammation and remodelling

Bradykinin, a pro-inflammatory molecule, and its related peptides have been studied for their effects on acute reactions in upper and lower airways, where they can be synthesised and metabolized after exposure to different stimuli including allergens and viral infection. Bradykinin B₁ and B₂ receptors are constitutively expressed in the airways on several residential and/or immune cells. Their expression can also be induced by inflammatory mediators, usually associated with eosinophil and neutrophil recruitment, such as IL-4, IL-13, TNF-α, IL-6 and IL-8, via intracellular MAPK and NF-κB signalling. In turn, the latters up-regulate both bradykinin receptors. Bradykinin activates epithelial/endothelial and immune cells, neurons and mesenchymal cells (such as fibroblasts, myofibroblasts and smooth muscle cells), which are implicated in the development of airway chronic inflammation, responsiveness and remodelling (a major feature of severe asthma). This review highlights the role of bradykinin and its receptors in respect to chronic inflammatory response involving eosinophils/neutrophils and to vascular/matrix-related airway remodelling in asthmatic airways. This scenario is especially important for understanding the mechanisms involved in the pathogenesis of eosinophilic and/or neutrophilic asthma and hence their therapeutic approach.